11 Nov
Displays

Understanding LCD Refresh Rate and Its Engineering Significance

The refresh rate of a Liquid Crystal Display (LCD) is a critical specification that reflects the number of times the display updates its image per second, typically measured in hertz (Hz). It plays a vital role in determining motion smoothness, response to fast-moving visuals, and synchronization with input signals. Understanding how refresh rate interacts with driving circuits, frame memory, and liquid crystal response characteristics is essential for optimizing both performance and power efficiency.

Let’s explores:

  • Real example calculation comparing 16-bit vs 24-bit RGB for a 7.0″ 1024×600 TFT panel
  • Key Parameters That Affect LCD Refresh Rate
  • How it continues to evolve with display technology.

Refresh rate means how many times per second the LCD updates the image on the screen.
It is measured in hertz (Hz) — for example:

  • 60 Hz → the display refreshes 60 times per second
  • 120 Hz → 120 times per second

Even though the image may not always visibly change, the panel still refreshes its pixels at that rate. A higher refresh rate usually gives smoother motion and less flicker.

Key Parameters That Affect LCD Refresh Rate

  1. Interface Bandwidth / Pixel Clock (DCLK or DOTCLK)
    • This is the most important factor.
    • The pixel clock defines how fast pixel data are transmitted from the driver (MCU, GPU, or controller) to the LCD module.
    • Formula (approx.):

Where

Example:
let’s go step by step with a 7.0″ TFT display (1024 × 600 resolution) and compare 16-bit RGB vs 24-bit RGB interface.

Step A. Basic Display Parameters

Item Symbol Typical Value
Active pixels (horizontal) H_active 1024
Active pixels (vertical) V_active 600
Horizontal blanking (porch + sync) H_blank 32
Vertical blanking (porch + sync) V_blank 23
Total horizontal pixels H_total 1024 + 32 = 1056
Total vertical pixels V_total 600 + 23 = 623

So total pixels per frame:

A 1024×600 TFT with a 40 MHz pixel clock →

Step B. Set Target Refresh Rate (e.g., 60 Hz)

We want:

Then pixel clock must be:

Conclusion:  Roughly a 40 MHz dot clock is needed for 60 Hz refresh.

Step C. Calculate Data Bandwidth

Case A: 16-bit RGB (RGB565)

Each pixel = 16 bits = 2 bytes

≈ 79 MB/s

Case B: 24-bit RGB (RGB888)

Each pixel = 24 bits = 3 bytes

≈ 118 MB/s

Step D. Compare

Parameter 16-bit RGB 24-bit RGB Difference
Bits per pixel 16 24 +50%
Bandwidth needed 632 Mbps 948 Mbps +50%
*Refresh rate (if pixel clock fixed at 40 MHz) 60 Hz ~40 Hz ↓ 33%
Color quality 65 K colors 16.7 M colors ↑ massively

*At any fixed interface bandwidth, 24-bit needs 50% more bandwidth than 16-bit, so its achievable refresh rate is 2/3 of 16-bit’s (if everything else is equal).

Step E. Critical Thinking:

  • The refresh rate is limited by the pixel clock (DCLK).
  • If your LCD controller has a fixed bandwidth, using 24-bit RGB means you must lower the refresh rate or use a faster clock / better interface (e.g. LVDS, MIPI-DSI).
  • For small embedded systems, 16-bit RGB is often chosen because it maintains 60 Hz refresh without needing a high-speed interface.

 

 

 

  1. Resolution (number of pixels)
    • Higher resolution = more pixels to refresh → requires a higher pixel clock to keep the same frame rate.
    • For example, 800×480 needs less bandwidth than 1920×1080 for the same refresh rate.
  2. Color Depth (Bits per Pixel)
    • 24-bit RGB (8 bits per color) transfers 50% more data than 16-bit RGB, so it may limit maximum refresh rate if bandwidth is fixed.
  3. Interface Type
    • Parallel RGB (DOTCLK) — refresh rate directly tied to pixel clock.
    • LVDS, eDP, MIPI-DSI — higher data rate interfaces that allow higher refresh rates.
    • SPI/MCU Interface — limited bandwidth, usually for lower resolution displays.
  4. Panel Response Time
    • Response time is how fast the liquid crystal changes state (in milliseconds).
    • Even if the refresh rate is high, slow response time can cause motion blur.

 

Parameter Impact on Refresh Rate Notes
Pixel Clock (DCLK)  Directly determines refresh rate Higher clock = faster refresh
Resolution Inversely proportional More pixels = lower refresh if clock fixed
Color Depth Affects data throughput Higher bit depth = slower if bandwidth limited
Interface Type Sets max possible rate SPI ≪ RGB ≪ LVDS/MIPI
Response Time Doesn’t change refresh rate but affects motion clarity Measured in ms

 

The relationship between refresh rate and refresh time is inversely proportional. As the refresh rate increases, the duration of each frame period decreases, allowing images to be updated more frequently. Table 1 below illustrates this relationship for several common refresh rate values used in LCD panels.

Table 1. Relationship Between Refresh Rate and Frame Refresh Time

Refresh Rate (Hz) Frame Time (milliseconds) Explanation
30 Hz 33.33 ms Each image is displayed for one-thirtieth of a second; suitable for static or low-motion displays.
60 Hz 16.67 ms Standard rate for most consumer LCDs; offers good balance between smoothness and power efficiency.
90 Hz 11.11 ms Provides noticeably smoother motion; used in high-end smartphones and VR headsets.
120 Hz 8.33 ms Common for gaming and automotive displays requiring fast motion response.
240 Hz 4.17 ms Enables extremely fluid motion; mainly used in professional gaming monitors and advanced prototypes.

 

From a performance standpoint, higher refresh rates improve motion fluidity and reduce flicker, resulting in a more stable and comfortable viewing experience. Applications such as gaming, augmented reality, and high-speed instrumentation often benefit from 120 Hz or higher operation. Conversely, static or semi-static displays operate efficiently at lower frequencies, balancing performance with energy savings. Adaptive and variable refresh rate technologies now dynamically adjust the frequency according to displayed content, achieving both visual stability and power optimization.

In summary, the refresh rate embodies a complex interaction between optical materials, electronic architecture, and perceptual quality. Through precise control of refresh timing and signal management, LCD technology continues to evolve toward faster, more power efficient, and more adaptive display performance.

 

Should you have any questions about LCD’s refresh rate, please consult our engineering.

04 Nov
Displays

3M VHB Introduction

What it is VHB?

  • “VHB” stands for Very High Bond. The tape family is a line of double-sided acrylic-foam adhesive tapes that are designed to permanently bond parts without mechanical fasteners.
  • The 5952 version (as an example) has a 0.045 in (≈1.1 mm) thick black foam core with modified acrylic adhesive on both sides.
  • The foam core is “viscoelastic” — meaning it has both viscous (flows to fill gaps) and elastic (resists deformation) properties.
  • The tape is marketed as able to replace rivets, screws, welds, and liquid adhesives in many applications.

Key Features & Benefits

  • Strong bond + structural load capability: Because the adhesive flows into microscopic irregularities and the foam distributes load, you get both peel and shear strength.
  • Weather / environment resistance: The VHB tapes are designed for outdoor use, with resistance to UV, moisture, solvents, temperature cycling.
  • Flexibility / conformability: The viscoelastic foam helps accommodate differences in thermal expansion, slight mismatches in surface, and vibration.
  • Aesthetics & clean finish: Because you avoid visible screws, rivets, or welds, you can get smoother surfaces and cleaner appearance.
  • Simplified assembly: Compared to drilling, welding, screwing, etc., tape is faster and cleaner (no debris, no need to finish welds).

Typical Use-Cases / Applications

  • Construction & Architecture: Bonding exterior panels, metal to metal, glass to metal, etc. The tape distributes load across the full bond area rather than concentrating at fasteners.
  • Transportation: Automotive, trains, buses — where you might want to eliminate rivets or welds for weight savings, smoother surfaces, quieter ride (less vibration).
  • Appliances & Electronics: For joining dissimilar materials (metal, glass, plastics) where aesthetics and sealed bond is important.
  • Signage / Displays: Attaching signs, panels, trim where mechanical fasteners might be unsightly or impractical.

Selecting the Right Tape & Practical Considerations

  • Surface Energy / Material compatibility: Some versions are optimized for high and medium surface energy substrates (metals, glass, rigid plastics). Others target low surface energy plastics. For example, one guide says the “49” family is broad-range, “59” family for powder-coated plastics.
  • Surface Preparation: Critical for good bond. Cleaning, possibly abrasion or priming may be required, especially for plastics or low surface energy materials.
  • Pressure & dwell: After application you should apply firm pressure to get good contact of the foam to surface. Some load-bearing capacity builds over time as the adhesive flows.
  • Temperature limits: For example, 5952 allows short-term use up to ~300 °F (≈149 °C) and long-term up to ~200 °F (≈93 °C) on certain surfaces.
  • Thickness and tolerances: Foam thickness matters (gap-filling ability, bond line). For 5952 the thickness is ~1.1 mm ±10%.
  • Mechanical loads & environment: Though the tape is very strong, design should account for the loads (peel is always the worst for adhesives), possible expansion/contraction, vibration fatigue. The viscoelastic nature helps but you still need good engineering.
  • Removal / permanence: These tapes are intended to be permanent. Removal is difficult without damage to substrate.
  • Cost vs traditional fasteners: Tape may have higher material cost, but installation savings and appearance may offset. Also weight savings for transport applications.

Comparison Chart: Key Families

Family Key Features Typical Use-Cases Example Tape
4941 / 49xx Family General-purpose acrylic foam core; good adhesion to high & medium surface energy substrates (metals, glass, many plastics) with good conformability. Bonding panels, nameplates, trim, sign mounting on common substrates. 3M VHB Tape 4941
5952 / 59xx Family Modified acrylic adhesive + very conformable foam core; broader substrate range including powder-coated paints & many plastics. More challenging surfaces (paint, powder coat, some plastics), bonding dissimilar materials. 3M VHB Tape 5952
RP+ Family Premium version for high strength, large panels, dissimilar materials; good for structural bonding. Structural assemblies, large metal panels, where fasteners would normally be used. 3M VHB Tape RP+ 160GF
Clear / Thin Bond / Specialty Families Variants for aesthetic or specialized requirements: e.g., clear adhesive for glass/transparent parts; thin bond for minimal gap; flame-retardant, low VOC, LSE (low surface energy) plastics. Transparent assemblies, very thin or flush bond lines, bonding plastics with very low surface energy, electronics. Examples: 3M VHB Tape 4910 (clear); 3M VHB Tape 5906 (thin bond)

 

Example Product Variants

Here are some sample variants with different spec and intended uses:

  • 3M VHB Tape 5952: A common black-foam variant for many painted and powder-coated metals, good all-round.
  • 3M VHB Tape 4910 Clear: Clear version – for aesthetic applications where black foam not acceptable.
  • 3M VHB Tape 4611 High‑Temp: Higher temperature capability, suited for pre-paint bonding (metal assemblies).
  • 3M VHB Tape RP+ 160GF: Specialized for dissimilar surfaces and high temperature (e.g., up to ~450 °F short-term).
  • 3M VHB Tape 5958FR Flame Retardant: Flame-retardant version for building codes / electrical enclosures.
  • 3M VHB Tape 4941 General Purpose: General purpose version for many medium-duty applications.
  • 3M VHB Tape 4959 Heavy Duty: For heavier structural bonding, e.g., aluminum skin to steel frames in transportation.
  • 3M VHB Tape 5906 Thin‑Bond: Designed for thin bond lines – when you want minimal thickness between joined parts.

Limitations & Things to Watch

  • While tape is very strong, design still needs to account for peel stresses, differential expansion, and fatigue/vibration. Just sticking things together without considering loads can lead to failure.
  • Surface preparation is vital. Contaminants, insufficient priming, or low surface energy plastics can reduce bond strength significantly.
  • Temperature extremes: Although many versions resist high temps, extreme heat or cold beyond spec will degrade adhesive performance.
  • Bond line thickness: Too thick or too thin a gap may degrade performance. The foam core is chosen partly to compensate for irregular surfaces, but there are limits.
  • Disassembly or repair: If you need to remove or service bonded parts frequently, mechanical fasteners might still be better.
  • Cost & supply: Some VHB variants cost significantly more than standard tapes or mechanical fasteners. For large area bonding, cost-benefit must be considered.

How to decide which family/version to use

Here are some decision factors (especially relevant given your hardware systems work) and what to check:

  • Substrate Materials & Surface Energy
    • High/medium surface energy (HSE/MSE) materials like aluminum, steel, glass, many painted plastics → general-purpose tapes (e.g., 4941 family) often suffice.
    • Low surface energy (LSE) plastics, oily surfaces, powder-coated paints, “hard-to-stick” plastics → go for more specialized (59xx family, LSE versions)
    • If bonding dissimilar materials (e.g., metal to plastic), you might want the higher strength/conformability of RP+ or 59xx families.
  • Gap / Surface Irregularity / Thickness
    • If surfaces are perfectly flat and well matched, a thinner core (e.g., 0.4 mm) may work.
    • If surfaces are irregular or have mismatches (texture, gaps), a thicker or more conformable foam helps (e.g., 1.1 mm typical for many)
    • For very thin bond line requirements (minimal thickness between parts) the “thin bond” specialty versions are an option.
  • Mechanical / Environmental Loads
    • Consider shear vs peel forces: adhesive tapes handle shear (parallel to surface) much better than peeling (perpendicular) so design joint accordingly. The design guide explains this.
    • Temperature: If your bonded assembly sees high bake-cycles, ovens, high ambient temperatures, choose a tape rated for higher temperature (e.g., RP+ or specialty high-temp families)
    • Outdoor, UV, moisture, vibration: All VHB tapes have good durability, but the higher spec versions give more margin.
  • Aesthetics / Hidden Fasteners
    • If you want clean visible surfaces (no screws/rivets) then tape is excellent.
    • If the bond line must be invisible or clear (glass to glass, transparent plastics), use a clear version (4910 family or similar).
  • Serviceability / Future Removal
    • Adhesive tapes are intended as permanent bonds; if you expect to disassemble frequently, you may want mechanical fasteners or hybrid (tape + fastener) approach.
  • Surface Preparation & Application
    • Clean surfaces well (remove grease, oxide, contamination). Some surfaces may need abrasion or priming.
    • Apply sufficient pressure during bonding to ensure full contact. Some dwell time may be required to reach full strength.

 

Should you have any questions about VHB, please consult our engineering.

16 Sep
Displays

Overview of Methods for Driving LED Backlight

1. Operating Principle of LEDs

Before designing a driver circuit, it is important to understand how an LED operates. The brightness of an LED is primarily determined by its forward voltage (VF) and forward current (IF). The current–voltage characteristic curve is shown in Figure 1. Here, VF represents the forward voltage drop, while IF is the forward current.

Once the applied forward voltage exceeds the threshold level (also known as the turn-on voltage, approximately 1.7 V in this case), IF can be considered nearly proportional to VF. As illustrated in the figure, the maximum forward current of an LED can reach up to 1 A, while the typical forward voltage range is about 2 V to 4 V.

 

Figure 1. Relationship between VF and IF

The forward voltage drop of an LED can vary over a relatively wide range (more than 1 V). From the VF–IF curve shown above, it is clear that even a small change in VF can cause a large variation in IF, which in turn leads to significant fluctuations in brightness. For this reason, the luminous characteristics of LEDs are generally described as a function of current rather than voltage.

However, in typical rectifier circuits, the output voltage fluctuates with changes in the mains supply voltage. This means that using a constant-voltage source cannot ensure consistent LED brightness and may negatively affect LED performance. Therefore, LED drivers are usually designed to operate as constant-current sources.

2. LED Driving Techniques

From the operating principle of LEDs, it is clear that to maintain optimal brightness, an LED must be driven by a constant-current source. The driver’s role is not only to ensure this constant-current characteristic but also to achieve low power consumption.

To meet these requirements, the commonly used methods of current control include:

  • Adjusting the value of a current-limiting resistor to regulate the current.
  • Varying the reference voltage across the current-limiting resistor to control the current.
  • Using PWM (Pulse Width Modulation) to achieve current regulation.

The techniques employed in LED drivers are very similar to those used in switch-mode power supplies. In essence, an LED driver is a type of power conversion circuit, but its output is a constant current rather than a constant voltage. Under all conditions, the circuit must deliver a stable, average current, with ripple current kept within a specified range.

(1) Current-Limiting Method
Figure 2 shows the simplest circuit that uses the current-limiting method.

 

Figure 2. Simplest Circuit of the Current-Limiting Method

As shown in Figure 3, this is the traditional circuit configuration. The mains voltage is stepped down, rectified, and filtered, then a series resistor is used for current limiting to keep the LED operating stably and to provide basic protection.

However, the fatal drawback of this approach is that the power dissipated in the resistor R directly reduces system efficiency. Combined with transformer losses, the overall system efficiency is only about 50%. Moreover, when the supply voltage fluctuates within ±10%, the current through the LED can vary by 25% or more, and the power delivered to the LED may change by over 30%.

The main advantage of resistor current limiting is its simplicity, low cost, and lack of electromagnetic interference (EMI). Nevertheless, its disadvantages are significant: the LED brightness changes with variations in VF, the efficiency is very low, and heat dissipation becomes a serious issue.

Figure 3. Traditional Resistor Current-Limiting Circuit

There is also a straightforward article online about the current-limiting method that can be referenced: https://www.ourpcb.com/current-limiting-resistor.html

For more information on constant-current LED backlight driving, see: https://www.orientdisplay.com/wp-content/uploads/2018/07/OrientDisplay-Backlight-Constant-Current-Driver.pdf

(2) Voltage Regulation Method
As shown in Figure 4, this circuit is based on Figure 3, with the addition of an integrated voltage regulator (MC7809). This keeps the output voltage essentially stable at 9 V, allowing the current-limiting resistor R to be made very small, which prevents voltage instability across the LED.

However, the efficiency of this circuit remains low. Since the voltage drop across both the MC7809 and resistor R1 is still significant, the overall efficiency is only about 40%. To achieve both stable LED operation and higher efficiency, low-power current-limiting components and circuits should be used to improve system performance.

The linear voltage regulation method has the advantages of simple structure, few external components, medium efficiency, and relatively low cost.

Figure 4 Voltage Regulation Method

(3) PWM Method
PWM (Pulse Width Modulation) controls LED brightness by adjusting the duty cycle of the driving current pulses. This dimming technique repeatedly switches the LED driver on and off using simple digital pulses. By supplying digital pulses of varying width, the output current can be modulated, thereby changing the brightness of a white LED.

The distinctive feature of this driving circuit is that energy is transferred to the load through an inductor. Typically, a PWM control signal is used to switch a MOSFET transistor on and off. By varying the duty cycle of the PWM signal and the charging/discharging time of the inductor, the ratio between input and output voltage can be regulated.

Common circuit topologies of this type include buck, boost, and buck–boost converters. The advantages of the PWM method are high efficiency and stable performance, but its drawbacks include audible noise, higher cost, and more complex design.

Figure 5. LED Driving Circuit Using PWM Method

As shown in Figure 5, the PWM signal is connected through the base of transistor VQ1 to the gate of a P-channel MOSFET. The gate of the P-channel MOSFET is driven by a simple NPN transistor amplification circuit, which improves the MOSFET’s conduction process and reduces the power consumed by the driver circuit.

If the MOSFET is driven directly by the circuit, the rapid switching on and off of the MOSFET can cause oscillations in the drain–source voltage. This may lead to radio frequency interference (RFI) and, in some cases, expose the MOSFET to excessively high voltages, resulting in breakdown and damage.

To address this problem, a non-inductive resistor is inserted in series between the gate of the driven MOSFET and the driver circuit output. When the PWM signal is at a high level, transistor VQ1 conducts, pulling the MOSFET gate voltage below the source voltage. As a result, the MOSFET turns on, and the LED lights up. Conversely, when the PWM signal is at a low level, VQ1 is cut off, the MOSFET turns off, and the LED is extinguished.

3. LED Driver IC Solutions

LED backlight driver ICs are primarily used in LCD displays (televisions, laptops, mobile phones, automotive screens, etc.) to provide a constant current or constant voltage to the LED modules. Their purpose is to ensure uniform brightness, high efficiency, and long lifetime. Common driver topologies include boost (step-up), buck (step-down), buck–boost, and multi-channel constant-current drivers. Below are several representative categories of LED backlight driver ICs:

(1). Texas Instruments (TI)

  • TPS61169: Single-channel boost constant-current driver, suitable for small-size LCDs (e.g., mobile phones).
  • LP8556: Supports I²C control, multi-channel output (up to 6 channels), and both PWM/analog dimming. Widely used in laptops and automotive displays.

(2). ON Semiconductor (now onsemi)

  • NCP3170 / NCP3170B: High-efficiency buck drivers, suited for small- to medium-size screens.
  • NCV7685: 16-channel constant-current driver, often used in automotive backlighting and dashboards, featuring high reliability and diagnostic functions.

(3). STMicroelectronics (ST)

  • STLED524: Multi-channel LED backlight driver with I²C interface.
  • L5973D: Boost DC-DC converter for medium-power LED backlight systems.

(4). Renesas Electronics

  • ISL98611: Integrates boost and positive/negative charge pump outputs, designed for smartphone power and backlight driving.
  • ISL97900: Multi-channel LED backlight driver with high-precision current matching.

(5). China Manufacturers

  • Macroblock (MBI series): e.g., MBI5030, focused on large-display and backlight drivers, widely used in TVs and advertising panels.
  • Solomon Systech: Has released LED backlight driver solutions for mobile phones and small-to-medium displays.
  1. Summary
  • Small-size screens (phones, tablets): TI TPS/LP series, Renesas ISL series.
  • Medium-to-large screens (laptops, monitors, TVs): Multi-channel constant-current drivers such as TI LP8556, ST STLED524, Macroblock MBI series.
  • Automotive and industrial applications: Require reliability and multi-channel control, typically using onsemi NCV series.

4. Comparison Table of LED Backlight Driver ICs

Manufacturer Model Channels Driving Method Control Interface Typical Applications
TI (Texas Instruments) TPS61169 Single-channel Boost constant-current PWM / Analog Mobile phones, small displays
TI LP8556 6 channels Multi-channel constant-current with boost I²C + PWM Laptops, automotive displays
onsemi (formerly ON Semiconductor) NCP3170 Single-channel Buck constant-current PWM Small- to medium-size screens
onsemi NCV7685 16 channels Constant-current SPI / I²C Automotive backlight, dashboards
ST (STMicroelectronics) STLED524 6 channels Multi-channel constant-current I²C Monitors, televisions
ST L5973D Single-channel Boost DC-DC constant-current PWM / Analog Medium-power backlight
Renesas ISL98611 3 channels + power outputs Boost + charge pump I²C Smartphones, tablets
Renesas ISL97900 Multi-channel Constant-current I²C Laptops, tablets
Macroblock (明微电子) MBI5030 16 channels Constant-current SPI TVs, large advertising displays
Solomon Systech (晶门科技) SSD series (e.g., SSD2805) 6–8 channels Multi-channel constant-current I²C Mobile phones, small-to-medium displays

5. Key Parameter Comparison of LED Backlight Driver ICs

Manufacturer Model Input Voltage Range Output Channels Max Current (per channel) Efficiency Package Typical Applications
TI TPS61169 2.7–18 V 1 1.2 A ~90% SOT-23 Mobile phones, small displays
TI LP8556 2.7–5.5 V 6 30 mA ~90% WQFN Laptops, automotive displays
onsemi NCP3170 4.5–18 V 1 3 A ~90% SOIC-8 Small- to medium-size screens
onsemi NCV7685 6–40 V 16 75 mA ~85% TSSOP Automotive backlight, dashboards
ST STLED524 2.7–5.5 V 6 30 mA ~85–90% QFN Laptops, monitors
ST L5973D 4–36 V 1 2 A ~90% HSOP-8 Industrial / medium-power backlight
Renesas ISL98611 2.5–5.5 V 3 + power rails 30 mA ~90% WLCSP Smartphones, tablets
Renesas ISL97900 2.5–5.5 V 6 25 mA ~90% QFN Laptops, tablets
Macroblock MBI5030 3–5.5 V 16 80 mA ~85% SSOP/QFN Large TVs, advertising panels
Solomon Systech SSD2805 2.7–5.5 V 6–8 25 mA ~85% QFN Mobile phones, small-to-medium displays

 

Key Comparison Points

1.      Number of Channels

o   Small screens → Single-channel (e.g., TPS61169)

o   Medium screens / Automotive → 6-channel (e.g., LP8556, STLED524)

o   Large screens / Televisions → 16 channels or more (e.g., NCV7685, MBI5030)

2.      Driving Method

o   Boost (step-up) → Common in smartphones and tablets, used to raise low supply voltages to higher levels for driving multiple LEDs in series.

o   Buck (step-down) → Better suited for high-voltage power sources driving fewer LEDs.

o   Multi-channel constant-current → Ensures brightness uniformity, ideal for large-screen backlighting.

3.      Control Interface

o   PWM → Simple, widely used in mobile devices.

o   I²C → More flexible, allows adjustable current, voltage, and dimming curves.

o   SPI → High-speed and multi-channel, well-suited for TVs and advertising displays.

 

6. Recommended Application Scenarios for LED Backlight Driver ICs

  • Small-size screens (smartphones / tablets) → Single-channel boost drivers, e.g., TI TPS61169, Renesas ISL98611
  • Medium-size screens (laptops / automotive displays) → 6-channel multi-channel constant-current drivers, e.g., TI LP8556, ST STLED524, Renesas ISL97900
  • Large-size screens (monitors / TVs) → 16-channel or higher constant-current drivers, e.g., Macroblock MBI5030
  • Special scenarios (automotive / advertising displays) → High-reliability multi-channel drivers, e.g., onsemi NCV7685, Macroblock MBI series
26 Aug
Displays

UV Protection Methods for Polarizers

Enhancing UV Resistance (100nm ~ 400nm) in Polarizers

Enhancing UV resistance (100nm ~ 400nm) is essential to prevent the polarizer layer from fading, degrading, yellowing, or failing due to ultraviolet exposure. Additionally, UV can damage the molecular structure of liquid crystals, leading to reduced performance. Once liquid crystal materials degrade, color deviation or yellow spots may occur, affecting display uniformity, image quality, and lifespan.

This time, we will focus on how to improve the UV resistance of polarizers.

 

Understanding Polarizer Structure and Process Flow

To understand how to enhance the UV resistance of a polarizer, we first need a basic understanding of its structure and manufacturing process.

 

General Structure of a Polarizer:

  1. Surface Coating:
    • Optional additional treatments.
    • Functional coatings applied directly to the surface of the TAC film.
    • Examples: Anti-scratch coatings (used in most polarizers), AR (Anti-Reflective), AF (Anti-Fingerprint), AS (Anti-Smudge), UV-blocking.
  2. Functional Film (Surface Protection Layer):
    • Optional additional film bonded to the TAC surface for enhanced performance.
    • Examples: Brightness enhancement film, UV protection, AF/AR/AS coatings, anti-static film.
  3. TAC Film (Triacetyl Cellulose) – Upper TAC:
    • Provides physical protection and structural support.
    • Protects the polarizer layer from scratches, moisture, oxidation, etc.
    • Offers mechanical strength and flexibility.
  4. PVA Polarizer Layer – Polyvinyl Alcohol:
    • The core functional layer.
    • After stretching, PVA molecules align with dye molecules, which selectively absorb light waves in a specific direction, thus achieving polarization.
  5. TAC Film – Lower TAC:
    • Symmetrical structure enhances mechanical strength.
    • Protects the underside of the polarizer layer.
  6. Pressure-Sensitive Adhesive (PSA) or Optical Clear Adhesive (OCA):
    • Bonds the polarizer to the LCD or touch panel glass.
    • Must remain transparent, bubble-free, and resistant to yellowing.
  7. Release Film or Protective Film

From this structure, it’s clear that the PVA polarizer layer is the most critical component. Therefore, to better understand how to enhance UV resistance, we must also understand the manufacturing process of the PVA polarizer layer.

 

PVA Polarizer Layer Manufacturing Steps

  • Dyeing:
    PVA is a water-soluble polymer. It is immersed in a solution containing iodine or organic dyes, which adhere to the film to form the polarizing material.
  • Stretching (Orientation):
    The dyed PVA film is stretched in one direction to align the dye molecules. These molecules selectively absorb light waves aligned with their direction, creating linearly polarized light. The transmitted light is perpendicular to the orientation of the dye.
  • Crosslinking Treatment (to enhance water resistance and stability):
    The stretched film is treated with chemical crosslinking agents such as boric acid and sodium ions to increase mechanical strength and moisture resistance.
  • Drying:
    The film is dried to remove excess moisture and stabilize the polarization effect.

 

Complete Production Flow of a Polarizer

Raw materials → Dyeing → Stretching → Crosslinking → Drying → Lamination → Cutting → Inspection → Packaging

 

Strategies to Enhance UV Resistance

Several structural and process-related measures can be taken to improve UV resistance:

  1. Surface Coating:

  • Apply UV-curable coatings containing UV protection components or nano UV shielding materials.
  • Provides a durable surface protection layer.

  1. Functional Protection Film:

  • Add UV barrier films (e.g., PET + UV coating) to further block short-wave UV rays.

  1. Upper and Lower TAC Films:

  • Use TAC films with UV absorbers to absorb UV rays (especially in the 280–400nm range), preventing penetration and protecting the internal PVA layer.
  • UV-absorbing or UV-reflecting coatings may also be applied to the TAC surface, especially in high-end applications.

  1. PVA Layer – Dyeing and Stretching:

Stretching Process:

  • During polarizer manufacturing, PVA films are dyed, then stretched to align dye molecules.
  • Unstretched PVA resembles tangled threads (random molecular chains), while stretched films have orderly aligned chains—like neatly combed hair—which control light direction.

How Stretching Enhances UV Resistance:

  1. Molecular Orientation Enhances UV Absorption (Indirect UV Protection):
    • Stretched PVA has highly ordered molecular chains, offering better light stability.
    • If UV-absorbing dyes are used (e.g., iodine-based), stretching aligns them for more effective UV absorption.
    • Even without dye, stretched PVA shows slightly enhanced UV absorption.
  2. Improved Structural Stability and UV Aging Resistance:
    • Stretching increases crystallinity and tightens molecular structure, improving UV durability.
    • Crucial for long-term exposure scenarios (e.g., outdoor sunglasses, automotive displays).
  3. Reduced Free Radical Pathways:
    • UV light excites unsaturated bonds in polymers, forming free radicals that cause degradation.
    • Ordered molecular structures reduce free radical diffusion, improving UV resilience.

Dyeing Process:

  • PVA alone absorbs little visible light—even after stretching—so polarization efficiency is low.
  • Dyes (like iodine) absorb light in specific directions and align with PVA chains during stretching to create high polarization efficiency (high transmission + high polarization).
  • Using UV-resistant, highly photostable dyes (e.g., special anthraquinone or azo dyes) prevents fading and extends lifespan.
  • Dye concentration must be controlled to avoid UV-accelerated degradation from overdosing.

Especially in LCDs, where high polarization performance is required, stretched dye films remain the most cost-effective and high-performance solution.

  1. Adhesive Layer (PSA/OCA):

  • Used to bond the two TAC films and the PVA layer.
  • Must be optically clear and durable.
  • Use optical adhesives with UV inhibitors to prevent yellowing, bubbling, or failure under UV.
  • Uniform coating/lamination without bubbles is critical to avoid UV leakage paths.

 

Summary: Key Points on UV Resistance in Polarizers

  1. UV radiation is the main external factor causing polarizer aging, especially for the PVA layer and dye structure. It leads to fading, breakage, contrast loss, and reduced display/module lifespan.
  2. UV resistance design involves both materials and structure:
    • Material level: Use TAC films, optical adhesives, and surface coatings with UV absorbers—mainstream absorbers include benzotriazole and triazine compounds.
    • Structural level: Stack UV-cut films or use UV coatings for enhanced shielding—especially critical for outdoor or in-vehicle applications with high UV exposure.
  3. Working principle of UV absorbers:
    • Convert UV energy into heat or harmless long-wave radiation, protecting the core PVA and dye layers from degradation.
    • UV cut performance is reflected in how well the entire structure limits UV (<400nm) transmission.
  4. Surface protection designs also play a key role:
    • Modern polarizers usually include a hard anti-scratch coating (HC).
    • Additional functional films (AR, anti-smudge, UV-blocking) may be added based on application needs vs. cost.
  5. System-level perspective:
    • Polarizers are just one part of the UV protection system.
    • Liquid crystals, light guide structures, and full module sealing are equally important.
    • UV resistance should be considered at the system design stage—for example, adding front-cover UV filter glass, using UV-resistant liquid crystal materials, etc.

 

Conclusion:

UV resistance is not just the task of a single material, but a multi-layered, multi-material system design strategy that directly affects the long-term stability and reliability of LCD displays.

 

30 Jul
Displays

Enhanced ESD Protection and EMI Shielding for Display Modules

Key Reasons for ESD Requirements for Displays Becoming Increasingly Common

  1. Electronic Components Are Becoming More Precise and Sensitive

    As technology advances, the internal components of displays—such as integrated circuits (ICs), driver chips, and touch panels (TP)—are becoming more miniaturized and low-power. This makes them less tolerant to electrostatic discharge (ESD), where even a small static charge can cause functional abnormalities, shorten the lifespan, or directly damage the components.

 

  1. Applications Are Becoming More Diverse and Complex

    Display usage has expanded beyond traditional indoor environments to more demanding settings, such as:

  • Industrial equipment: frequent friction and dust accumulation easily generate static electricity
  • Medical devices: require high reliability and safety
  • Automotive systems: enclosed environments easily lead to electrostatic induction
  • Outdoor terminals: dry climates increase the risk of static charge build-up

 

  1. Widespread Use of Touch Technology

    As touch displays become more common, users frequently interact directly with the screen. In dry environments or when wearing synthetic fabrics, it is easy to generate static electricity. Discharge directly onto the touch surface poses a greater risk to circuit integrity, so enhancing surface-level ESD protection is essential.

Our standard TFT displays typically meet the following ESD protection levels:

  • Air discharge: ±8KV
  • Contact discharge: ±4KV

These are in line with the specifications described in our datasheets and are essential for ensuring product reliability.

 

  1. With increasing application demands and evolving environmental challenges, higher Electrostatic Discharge (ESD) protection levels are often required for display modules

particularly in industrial, automotive, and outdoor settings. When customers request enhanced ESD performance, such as:

  • Air Discharge: ±15KV
  • Contact Discharge: ±8KV

 

Recommended Solution: Double-sided EMI Shielding

Component: FPC Shielding Layer
Structure: Double-sided EMI (Electromagnetic Interference) Shielding Film

Description:

To improve the Electromagnetic Compatibility (EMC) of the display module, we recommend the use of a Double-sided EMI shielding structure. This design involves applying EMI shielding materials to both the front and back sides of the display module.

 Key Functions:

  • Effectively suppresses internal and external electromagnetic interference
  • Enhances the stability and reliability of signal transmission
  • Helps meet higher ESD immunity levels as specified in IEC 61000-4-2 standards

 

 

 

Additional Recommendations

In addition to the EMI shielding layer, further system-level measures can be considered

  • Grounding design optimization between module and enclosure
  • Use of conductive foam or gasket around the module perimeter
  • Application of anti-static coatings or films on exposed surfaces

EMI shielding material is like an “umbrella” that blocks interference.
Grounding wire is like a “drainpipe” that channels interference away.

Only by combining both can we achieve a true “shielding + discharge” integrated protection.

Examples of Common Grounding Methods:

Application Area Grounding Method
LCM metal backplate Connected to the mainboard GND point
Touch FPC shielding layer Grounded via GND pin or metal frame
Conductive foam/tape Attached to grounding copper foil or metal housing
EMI shielding sticker Connected to grounding point on housing or bracket

 

Signal Ground vs. Chassis Ground

Although both are referred to as “ground,” Signal Ground and Chassis (Physical) Ground have different purposes and characteristics in electronics:

Signal Ground (Logic Ground)

Purpose: Serves as a voltage reference for signal transmission (typically 0V)

Location: Internal circuit ground used by ICs, resistors, capacitors, etc.

Characteristics:

    • Used in logic and analog circuits
    • Not necessarily connected to the earth
    • Typically found in low-noise, low-current environments

Example: The GND pin of an MCU or sensor

Chassis Ground / Earth Ground

Used once the display module is integrated into the full device

Purpose:

    • Discharge static electricity (ESD) to prevent component damage
    • Reduce EMI via housing-level shielding
    • Improve EMC performance through unified grounding

Example: Metal frame, conductive tape, or backlight housing grounded to the device chassis

 

Summary

To meet elevated ESD requirements (±15KV air / ±8KV contact), both EMI shielding and effective grounding are essential.
By combining signal-level reference grounding with chassis-level discharge pathways, and by incorporating double-sided EMI shielding, we can ensure robust protection, greater product reliability, and compliance with industrial EMC/ESD standards.

 

Does your project have special requirements for ESD protection? Feel free to contact our engineer at <tech@orientdisplay.com>—we’re always happy to help.

24 Jul
Displays

How to Estimate Battery Life for Your Device – Even with Sleep Modes

Whether you’re designing a sensor node, a wearable device, or a portable gadget, battery life estimation is a key part of the process. Here’s a simple way to calculate how long your battery will last — even if your device switches between active and sleep modes.

Basic Formula (For Constant Current)

If your device draws a constant current, battery life is easy to estimate:

Battery Life (hours) = Battery Capacity (mAh) / Device Current Consumption (mA)

Example:
– Battery: 2200 mAh
– Device current: 40 mA
Battery Life = 2200 / 40 = 55 hours

When Your Device Has Sleep and Active Modes

In most real-world applications, devices don’t run at full power 24/7. They might wake up briefly, do some work, then return to low-power sleep mode.

To account for this, you’ll need to calculate the average current draw across the full duty cycle (i.e., one full period of activity and sleep).

Step-by-Step Example

Let’s say your device:
– Draws 40 mA when active, and stays active for 2 seconds
– Draws 0.1 mA when sleeping, and sleeps for 8 seconds
– Total cycle = 10 seconds

Step 1: Compute Average Current
Average Current = ((40 * 2) + (0.1 * 8)) / 10 = (80 + 0.8) / 10 = 8.08 mA

Step 2: Estimate Battery Life
Using a 2200 mAh battery:
Battery Life = 2200 / 8.08 ≈ 272.3 hours

Real-World Considerations

While this gives a solid estimate, keep in mind:
– Battery capacity decreases with age and cold temperatures.
– Devices may consume extra current during startup, communication bursts, or sensor sampling.
– Battery cutoff voltage matters — some devices shut down before the battery is truly empty.

Final Tip

Use this method during your design phase to make informed decisions about battery size, duty cycles, and sleep strategies. Optimizing power usage can drastically extend your product’s life between charges.

If you’d like to make this easier, feel free to reach out — our engineers are happy to help.

 

21 Jul
Displays

Peck Model and Lifetime Evaluation: MTTF, MTBF, and Experimental Design

When evaluating the service life of a product, we often inform customers that the expected lifetime is 50,000 hours. However, this number is not derived from actual testing, but rather from theoretical calculations.

 

The method for measuring actual product lifespan is HALT (Highly Accelerated Life Test). HALT is a testing methodology that applies stress conditions far beyond normal usage—such as high/low temperatures, rapid thermal cycling, and vibration—to quickly expose potential weaknesses in a product. The primary purpose of HALT is not to determine the product’s exact lifespan, but to identify design flaws and early failure mechanisms, and to pinpoint which components are most susceptible to damage.

 

In practice, however, we more commonly use MTTF (Mean Time To Failure)-based evaluation strategies. MTTF is a quantitative reliability metric based on statistical lifetime distribution models (such as exponential or Weibull distributions). It estimates the average lifetime of a product by operating a set number of samples under standard or accelerated conditions, recording any failures over time.

 

The following table presents a real-world case we encountered. The accelerated aging model we used for analysis was the Peck model.

 

 

Introduction to the Peck Model

The Peck model is an empirical model used to predict the accelerated aging of electronic components and materials under the combined effects of temperature and humidity. Unlike the traditional Arrhenius model, which considers only temperature, the Peck model introduces a humidity exponent parameter, making it more suitable for simulating the impact of hot and humid environments on product lifetime. Its mathematical expression is:

Where:

  • AF is the acceleration factor,
  • RH is the relative humidity,
  • n is the humidity exponent (typically ranging from 2 to 4; we use 3),
  • E is the activation energy (commonly 0.7 eV for LCDs),
  • k is the Boltzmann constant,
  • T is the absolute temperature in Kelvin.

Using this model, the duration of an accelerated test can be converted into an equivalent lifetime under normal operating conditions.

For example, in our table, by substituting the following values:

RHtest​: test relative humidity (90%)

RHuse​: usage relative humidity (50%)

Ttest​=333.15K

Tuse=298.15K

Ea ​=0.7eV

k=8.617×10−5 eV/K

n=3

AF=102.7

Equivalent Operating Time T=240hrs*102.7=24,648hrs.

Next, we need to substitute T into the MTBF formula.

 

Definition and Difference Between MTTF and MTBF

Both MTTF and MTBF are used to describe product reliability, but they apply to slightly different scenarios.

MTTF (Mean Time To Failure) refers to the average time a device operates before its first failure. It is applicable to non-repairable systems and represents the statistical expected lifetime, reflecting the reliability level of a product.

MTBF (Mean Time Between Failures) is typically used for repairable systems, and indicates the average operating time between two consecutive failures. For non-repairable systems (such as LCDs in our testing, which cannot be repaired once damaged), MTBF can be approximated as MTTF.

 

The formula for MTBF is as follows:

To calculate reliability from MTBF, the formula is as follows:

Experimental Design

Test Objectives:

Achieve the required MTBF lower bound corresponding to a 10-year lifetime, with both 5-year and 10-year reliability exceeding 90% under known conditions.

Equivalent test time per unit: 24,648 hours (based on extrapolation from 240 hours at 60°C / 90% RH using the Peck model).

Confidence levels: Sample size calculations for 90%, 95%, and 99% confidence levels.

Sample Size Requirements (Based on MTBF Reliability Calculation):

Confidence Level Samples for 90% Reliability @ 5 Years Samples for 90% Reliability @ 10 Years
90% 39 78
95% 54 101
99% 83 156

Test Plan Details:

  • Sample Size: Select based on desired reliability and confidence level; it is recommended to include a margin for contingency.
  • Test Conditions: Continuous aging under 60°C / 90% RH for at least 240 hours (widely accepted industry standard).
  • Data Monitoring: All failure events and times must be recorded throughout the test. If any failures occur, recalculate and adjust the plan accordingly.
  • Periodic Assessment: After testing, use the Peck model to convert the test duration to equivalent lifetime. Evaluate MTBF and reliability using appropriate statistical methods.
  • Risk Management: In case of failures, analyze the failure modes, adjust materials or processes, and optimize the design as needed.

 

Expected Conclusion:

If 78 samples are tested under 60°C / 90% RH for 240 hours, and no failures occur, the equivalent 10-year reliability of the product can be estimated at 90% (i.e., only 10% of units are expected to fail), which meets the general standard for consumer electronics (typically 80–90% reliability).

In contrast, if only 5 samples are tested (as shown in the initial table), the 5-year reliability would be just 43.9%, meaning that nearly half the units are expected to fail within 5 years—a conclusion that is not favorable for presentation to customers.

 

Contact our engineering team: tech@orientdisplay.com

07 Jul
Displays

The Complete Guide to Display Coatings: How AG, AF, and AR Solutions Solve Critical Display Problems

Why Do Display Coating Problems Cost Businesses Money?

Every day, businesses lose productivity and customer satisfaction due to display readability issues. Outdoor kiosks become unreadable in sunlight. Medical equipment screens create dangerous glare for healthcare workers. Touch devices accumulate fingerprints, which can be frustrating for users and require regular cleaning. Industrial control panels reflect overhead lighting, making critical information difficult to see.

At Orient Display, we’ve engineered coating solutions to help manufacturers solve these exact problems across automotive, medical, industrial, and consumer applications. The right coating choice can mean the difference between a display that enhances user experience and one that creates operational headaches.

What Are AG, AF, and AR Display Coatings?

Display coatings are specialized surface treatments that solve specific visibility and usability problems. The three most effective solutions are:

AG (Anti-Glare) reduces harsh reflections and eye strain by creating a matte surface that scatters light, making displays more comfortable to view under bright lighting.

AF (Anti-Fingerprint) creates an oil and water-repelling surface that prevents fingerprint buildup and makes displays easier to clean, crucial for touch interfaces.

AR (Anti-Reflection) uses optical interference to eliminate mirror-like reflections while maintaining crystal-clear image quality, essential for outdoor and high-brightness applications.

How Do These Coatings Compare for Performance and Applications?

Based on our extensive testing and customer deployments, here’s how these coatings perform across key metrics:

Coating Type Primary Function Surface Appearance Best Applications Key Benefit
AG (Anti-Glare) Reduces harsh glare and eye strain Matte finish with slight texture Indoor displays, office equipment, reading devices Enhanced visual comfort in bright environments
AF (Anti-Fingerprint) Repels oils and fingerprints Smooth, easy-to-clean surface Touch screens, mobile devices, kiosks Reduced maintenance, improved touch experience
AR (Anti-Reflection) Eliminates reflections, increases light transmission Crystal clear, transparent Outdoor displays, automotive, high-end electronics Maximum clarity and contrast in all lighting

Can You Combine Different Coating Types?

Yes, and many applications benefit significantly from combined treatments. Here’s what our engineering experience has shown works best:

Coating Combination Performance Benefits Best Use Cases Trade-offs to Consider
AG + AR Enhanced visual comfort with improved clarity Automotive displays, industrial HMI Slight reduction in sharpness due to AG matte effect
AG + AF Comfortable viewing plus easy cleaning Office equipment, indoor kiosks AF layer must be matched to AG surface texture
AR + AF Maximum clarity with fingerprint resistance High-end smartphones, tablets, premium displays Higher cost but superior user experience
AG + AR + AF Complete protection and performance Medical equipment, luxury automotive, outdoor industrial displays Highest cost and processing complexity

What’s the Best Coating for Outdoor Displays?

For outdoor applications, AR (Anti-Reflection) coating is typically the superior choice for outdoor use scenarios.

Outdoor displays face direct sunlight, which creates intense reflections that make screens unreadable. AR coating provides enhanced clarity and anti-reflection performance. AR coating can significantly improve visibility in bright outdoor conditions.

However, for cost-sensitive outdoor applications, AG coating is often recommended for cost-sensitive outdoor use, providing a reasonable compromise for glare reduction.

Our Recommendation: For applications requiring maximum clarity and outdoor visibility, choose AR coating. For budget-conscious applications, AG provides good value for outdoor glare reduction.

Which Coating Should Automotive Manufacturers Choose?

Automotive displays require the most demanding performance standards due to safety implications and harsh operating conditions. Based on our automotive partnerships, here’s what works:

For Dashboard and Center Console Displays: For automotive and industrial HMIs, we recommend:

  • AG + AR or AG + AR + AF composite treatment provides optimal performance
  • AG reduces glare and relieves visual fatigue
  • AR reduces reflectance and enhances image clarity
  • AF prevents fingerprint buildup that could obstruct critical information

For HUD (Head-Up Display) Applications:

  • AR coating is essential to prevent double imaging
  • Must achieve very low reflectance for optical clarity
  • Requires high-performance AR treatment for durability

What Coating Works Best for Touch Devices?

Touch devices prioritize feel, cleanliness, and visual quality. Here’s our recommended approach:

For Consumer Electronics (Phones, Tablets):

  • AF + AR combination delivers the best user experience
  • AF coating provides a smooth touch feel and fingerprint resistance
  • AR coating maintains display clarity and reduces battery drain from increased brightness compensation

For Industrial Touch Panels:

  • AG + AF combination handles harsh usage patterns
  • AG reduces glare in industrial lighting environments
  • AF coating must withstand frequent cleaning with industrial solvents

How Are These Coatings Manufactured and Applied?

Understanding the manufacturing process helps explain performance differences and cost variations. Here are the primary methods we use:

AG (Anti-Glare) Processing Methods

Chemical Etching (Glass Applications)

  • Process: Acid etching creates microscopic surface irregularities
  • Performance: 88-91% light transmission, 3-6% reflectance
  • Best for: High-durability applications, harsh environments
  • Cost: Medium

AG Film Application

  • Process: Micro-particle resin coating applied to PET film base
  • Performance: 89-93% light transmission, 2-4% reflectance
  • Best for: Cost-effective applications, easy installation
  • Cost: Medium to high

AF (Anti-Fingerprint) Processing Methods

Physical Vapor Deposition (PVD)

  • Process: Vacuum deposition of fluorinated compounds
  • Performance: Contact angle up to 120°, >6H hardness
  • Best for: High-durability, frequent-touch applications
  • Cost: High

Solvent-Based Coating

  • Process: Solution application of fluorosilane compounds
  • Performance: Contact angle 100-115°, moderate durability
  • Best for: Standard consumer applications
  • Cost: Low to medium

UV-Cured Nanocoating

  • Process: UV-polymerized fluoropolymer coating
  • Performance: Contact angle 95-110°, good weather resistance
  • Best for: Outdoor applications, balanced cost/performance
  • Cost: Medium

AR (Anti-Reflection) Processing Methods

Vacuum Thin-Film Coating

  • Process: Multi-layer optical films (MgF₂, SiO₂, TiO₂) deposited in vacuum
  • Performance: <0.5% reflectance, 97-99% transmission
  • Best for: Premium applications requiring maximum performance
  • Cost: High

Sol-Gel Nanocoating

  • Process: Spray or dip application of nanoscale materials
  • Performance: 1-2% reflectance, 96-98% transmission
  • Best for: Cost-effective AR solution
  • Cost: Medium

Moth-Eye Nanostructure

  • Process: Etched nanoscale surface structures
  • Performance: <0.2% reflectance, 98-99% transmission
  • Best for: Ultra-premium applications, wide viewing angles
  • Cost: Very high

How Long Do Different Coating Types Last?

AF film adhesion and service life depend on the substrate and coating technology; it is prone to wear in environments with frequent wiping. Chemical-etched AG glass provides high durability with abrasion resistance, while AG films depend on the coating quality.

Key Durability Factors:

  • Chemical-etched AG: High durability, abrasion resistant
  • AG Films: Durability depends on coating quality
  • PVD AF: Superior adhesion and longevity compared to other AF methods
  • Solvent-based AF: Average durability, prone to degradation
  • Vacuum AR coating: Excellent stability and long durability

Coating durability directly impacts total cost of ownership and should be considered when selecting treatments for specific applications.

How Much Do Different Coatings Cost?

Coating costs vary but does not provide specific cost multipliers. Cost considerations include initial treatment, durability, and maintenance over the product lifecycle. Different processing methods have varying cost implications:

  • Chemical etching: Medium cost
  • AG Film: Medium to high cost
  • PVD AF: High cost
  • Solvent-based AF: Low to medium cost
  • UV-cured AF: Medium cost
  • Vacuum AR: High cost
  • Sol-Gel AR: Medium cost
  • Moth-Eye nanostructure: Very high cost

High-end products often employ AG + AR + AF three-layer composite films or coatings, which have the highest cost and greatest processing difficulty.

What Makes Orient Display’s Coating Solutions Different?

Our 2 decades of display engineering experience mean we understand both the technical requirements and real-world challenges our customers face. We provide comprehensive technical analysis and application-specific recommendations to help you select the optimal coating solution.

Technical Expertise: We offer detailed guidance on coating selection, processing methods, and performance optimization for specific applications across automotive, medical, industrial, and consumer electronics sectors. Our engineering team understands the critical performance requirements for each application type and can recommend the most effective coating combinations for your specific needs.

Contact our engineering team to request a consultation: tech@orientdisplay.com

How Do I Choose the Right Coating for My Application?

Use this decision framework based on your primary requirements:

Step 1: Identify Your Primary Challenge

  • Glare/Eye Strain: Start with AG coating evaluation
  • Fingerprints/Cleaning: Prioritize AF coating solutions
  • Reflections/Outdoor Visibility: Focus on AR coating options

Step 2: Consider Your Environment

  • Indoor/Controlled Lighting: AG or AF coating often sufficient
  • Outdoor/Variable Lighting: AR coating typically required
  • High-Touch Applications: AF coating essential

Step 3: Evaluate Performance Requirements

  • Consumer Products: Balance cost and performance
  • Professional/Industrial: Prioritize durability and reliability
  • Safety-Critical: Choose proven, high-performance solutions

Step 4: Assess Total Cost of Ownership

  • Initial Cost: Compare coating treatment costs
  • Maintenance: Factor in cleaning and replacement costs
  • User Experience: Consider productivity and satisfaction impacts

What Questions Should I Ask When Selecting a Coating Partner?

When evaluating coating suppliers, these questions reveal technical capability and experience:

Technical Questions:

  • What specific coating processes do you control in-house?
  • Can you provide performance data from similar applications?
  • How do you ensure coating uniformity across large displays?
  • What quality control testing do you perform?

Experience Questions:

  • How many similar projects have you completed?
  • Can you provide customer references in my industry?
  • What technical challenges have you solved for similar applications?
  • How do you handle custom coating requirements?

Support Questions:

  • What engineering support do you provide during design?
  • How do you handle performance testing and validation?
  • What documentation and certification can you provide?
  • How do you support field issues or warranty claims?

Ready to Solve Your Display Coating Challenges?

Whether you’re dealing with outdoor readability issues, fingerprint accumulation, or glare problems, the right coating solution can transform your display performance. Our engineering team has solved these exact challenges across thousands of applications.

Next Steps:

  1. Technical Consultation: Share your application requirements with our engineering team
  2. Performance Testing: We’ll recommend optimal coating solutions and provide test samples
  3. Cost Analysis: Receive detailed pricing and total cost of ownership analysis
  4. Production Planning: Integrate coating solutions into your manufacturing timeline

Contact our engineering team: tech@orientdisplay.com

Request a consultation: Share your display specifications, operating environment, and performance requirements for customized coating recommendations.

Orient Display has been engineering custom display solutions with expertise spanning automotive, medical, industrial, and consumer electronics applications. Our coating solutions are deployed in devices worldwide, from automotive dashboards to medical equipment interfaces.

23 Jun
Displays

Dual-Layer LCD Architecture Balancing Power Efficiency and Visual Performance

Introducing a Smarter Low-Power LCD Design for Small Home Appliances

In the ever-evolving world of smart appliances, power efficiency and user experience are equally vital. We’re excited to introduce our innovative dual-layer LCD solution, designed specifically for small home appliance applications that demand both high-resolution visuals and ultra-low-power standby modes.

The Architecture: Two Displays in One Panel

Our LCD module integrates two independent layers:

Upper Layer: Segment-type SVTN (VA panel)

Lower Layer: High-resolution IPS panel

This unique structure allows the device to switch seamlessly between high-performance display and low-power standby mode:

IPS Display (Active Mode):
When the device is in use, the vibrant IPS panel delivers a crisp, detailed user interface.

SVTN (VA) Display (Standby Mode):
When idle, the device shifts to the VA segment display. This layer consumes extremely low power, and can still display dynamic information like time, temperature, or status updates. To further reduce energy use, the backlight can be dimmed without losing visibility.

 

Why Not Use RAM-LCD ICs Instead?

While an alternative solution is to use a RAM-integrated LCD driver IC, that approach has several limitations:

  1. Static-only content unless the MCU frequently wakes up—leading to more power consumption.
  2. Software complexity increases significantly with real-time content.
  3. Higher BOM cost due to limited IC availability and premium pricing.

In contrast, our SVTN (VA) -based design is:

  1. Software-friendly: Minimal MCU involvement needed.
  2. Cost-effective: SVTN (VA) segments are simpler to drive, and component selection is broader.
  3. Power-efficient with dynamic capability.

Application Scenarios

Smart kettles, cookers, and humidifiers

IoT-enabled thermostats or timers

Battery-powered home gadgets requiring long standby time

 

17 Jun
Displays

E-ink Digital Art Frame Introduction

History of E-Ink Digital Art Frames

 

Early Inspiration (2000s) – E Ink’s Birth and First Uses

E Ink or E-Paper was invented at MIT in the late 1990s  (later commercialized by E Ink Corporation in 1997). Its first major application was eReaders like the Amazon Kindle, thanks to its paper-like readability and low power consumption.

During this time, digital picture frames using LCDs began to appear, but they were power-hungry and always needed to be plugged in. While people loved the idea of dynamic art displays, traditional LCDs weren’t ideal for minimalist or power-efficient decor—enter e-ink.

Niche and Experimental Frames (2010–2015)

In the early 2010s, some DIY enthusiasts and early adopters began using small ePaper displays (like those from Pervasive Displays or Waveshare) to create custom digital frames. These were typically black-and-white, used for line drawings or comics, and updated via Raspberry Pi or Arduino.

Projects like:

  • Framed 2.0 (2014 Kickstarter) tried using e-ink for art but pivoted to high-end LCD.
  • Kindle hacks let people display static images or art on old Kindle screens.

These were creative but limited, due to small screen sizes, low resolution, and lack of color.

Commercial Emergence (2016–2020)

As E Ink technology improved, a few startups began releasing dedicated e-ink digital art frames, emphasizing minimalism, aesthetic calmness, and zero light pollution. Key players included:

  • Modos Paper Monitor – focused on productivity and code/art display
  • Visionect / Joan – used e-ink for signage but inspired display ideas
  • Framestation, Inkplate – DIY-friendly open-source displays

Still, most were DIY or commercial signage rather than high-resolution color frames for digital fine art.

Breakthroughs with Color E Ink (2020–2023)

The launch of E Ink Kaleido (color filter) and Spectra (multi-color particles) marked a turning point. These allowed for limited color digital art, though still with lower saturation than LCDs.

Now, new products like:

  • Lemur Ink – aimed at artists and collectors
  • Color e-ink photo frames from China (Alibaba, Waveshare panels)
  • QuirkLogic and Mudita – focused on lifestyle calmness and intentional display

They emphasized ultra-low power, eco-friendliness, and aesthetic quietness, aligning with modern interior design and wellness trends.

Spectra 6 and the Future (2024+)

With E Ink Spectra 6 in 2023–2024, digital art frames can now display six vivid colors (including blue and green) with high contrast (30:1) and resolutions up to 200 PPI.

This enables:

  • Larger frame sizes (up to 75”)
  • Museum-quality visuals
  • Ultra-low power “always-on” displays
  • Integration with NFT galleries and generative art

Startups and artists are now exploring connected art platforms, where owners can stream curated artworks or generative visuals to their frame via Wi-Fi or blockchain wallets.

 

What is E-Ink Spectra 6

 

E Ink Spectra 6 is the latest generation of color electronic paper (ePaper) display technology developed by E Ink Corporation, designed specifically for retail signage, digital art, and low-power displays. It represents a major leap forward in color richness, contrast, and resolution compared to previous e-ink color technologies.

Key Features of E-Ink Spectra 6

Feature                           Details

🖍️ Color Range          Six pigments: black, white, red, yellow, blue, and green

🌈 Color Accuracy    Capable of displaying over 60,000 colors via advanced dithering

📐 Resolution             Up to 200 PPI (pixels per inch) for detailed, crisp images

🌓 Contrast Ratio      Up to 30:1 — much higher than previous color e-ink generations

⚡ Power Usage         No power required to retain an image (bi-stable); updates use power

🔋 Battery Life            Can last months to years on a single charge depending on usage

🖥️ Sizes Available     Ranges from 4″ to 75″ — popular sizes include 7.3″, 13.3″, 25.3″

🧩 Interface Options              SPI, USB, BLE, or Wi-Fi depending on integration hardware

E Ink Spectra 6 is the most vibrant, color-accurate, and power-efficient ePaper technology available for static displays. It’s opening new doors in digital art, signage, and ambient visual tech—where beauty meets sustainability.

 

How E-ink Spectra 6 works

E Ink Spectra 6 uses microcapsules filled with charged color particles suspended in fluid. By applying different electrical charges, the desired pigment rises to the surface, forming pixels in any of the six colors. Once in place, the image stays without power until the next refresh.

For more information, please visit: https://www.eink.com/tech/detail/How_it_works

 

The Popular E-Ink Digital Art Frames Sizes

Size       Resolution PPI
4″ 600*400 ~180
7.3″ 800*480 127
10” 1600*1200 200
8.14″ 1024*576 144
13.3″ 1200*1600 150
25.3″ 3200*1800 145
28.5”  2160*3080 132
31.5″ 2560*1440 94

 

The Players in E-Ink Digital Art Frames

A lot of startups have been working on E-Ink Digital Art Frames, but all of them use Spectra 6.  The most well known ones are listed as below.

Bloomin8 (by Arpobot)

  • A crowd‑funded digital art frame debuting March 19, 2025 on Kickstarter/Indiegogo.
  • Available in 7.3″, 13.3″, and 28.5″ sizes, battery-powered (up to ~1 year), and Wi‑Fi/Bluetooth/Job‑Assistant compatible

Reflection Frame (Creative Design Worx)

  • A 13.3″ Spectra 6 frame featuring NFC pairing, Bluetooth LE updates via smartphone, Kickstarter‑backed ($249–329 early bird).
  • UI connectivity is optimized for simplicity and power efficiency

InkPoster (PocketBook + Sharp)

  • A digital wall poster/art display available in 13.3″, 28.5″, 31.5″ sizes.
  • Charges once a year, equipped with Wi‑Fi/Bluetooth, app-connected for curated artworks and personal uploads

These platforms illustrate the shift from display hardware to connected art ecosystems—powered by APIs, smartphone apps, and even AI content generation. Whether you’re a collector or creative, these Spectra 6 frames offer nearly silent, power-efficient, and paper-like canvases that softly transform your space.

The full list players are listed below:

Aluratek Kickstarter – https://www.kickstarter.com/projects/…

Bloomin8 – https://bloomin8.com/product/einkcanvas

Reflection Frame – https://www.reflectionframe.com/

Inkposter – https://inkposter.com

Paperless Paper – https://paperlesspaper.de/e

Samsung EDMX

 

What Orient Display is Involved in E-Ink Digital Art Frames Creations?

  • E-ink Spectra 6 EDP sourcing
  • Laminate the protection glass to EDP
  • Touch design, manufacturing and integration.
  • Front Light, design, manufacturing and Integration (if any crazy ideas)
  • EDP driving board includes PCB layout, SMT, testing and firmware. Our engineers are familiar with ESP32.
  • Housing and frame with aluminum, plastic or wood material.
  • The whole assembly and packaging.

 

If you have any questions, please contact our engineering team.

Browse our standard E-Ink products from our online store.

 

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