Methods to Increase LCD Display Brightness
Brightness is an important parameter of tft display, and there are many influences of brightness. Not only does it look a bit dark, a low-brightness display cannot be used in an outdoor environment, and a high-brightness sunlight readable display is required, and the brightness will change the color.
Increase LED Backlight Brightness:
An effective approach to boost LCD display brightness is by increasing the number of LED bulbs in the backlight unit. By doing so, the amount of light emitted is augmented, resulting in a more vibrant and vivid display. However, it’s essential to strike a balance between the desired brightness and the limitations posed by available space and power capacity. Careful evaluation is necessary to determine if the display can accommodate additional LED bulbs without compromising other aspects of its functionality.
Different Films for Brightening:
Using brightening films, also known as prism films or light-enhancing films, can improve brightness. These films consist of three layers: a back coating providing a certain level of haze to diffuse incoming light, a transparent PET substrate layer in the middle, and a micro-prism structure on the top emitting surface. It is worth noting that the improvement in brightness has certain limitations.
More Efficient Light Guide Plate:
The light guide plate is a critical optical component within the LED backlight system. Its primary function is to convert the horizontally emitted light from the LED bulbs into vertically directed light, which enhances the overall brightness of the LCD display. As manufacturers strive to make displays thinner and more compact, the challenge lies in maintaining high light conversion efficiency. Designing and implementing an efficient light guide plate that ensures maximum light utilization becomes essential. By utilizing advanced optical technologies and materials, the light guide plate’s efficiency can be improved, resulting in brighter LCD displays.
High-brightness LED Chips or Dual-Core LEDs:
In cases where structural constraints limit the addition of more LED bulbs, alternative options can be explored. One such option is utilizing high-intensity LED bulbs, which generate brighter light output compared to standard LED bulbs. This approach allows for increased brightness without compromising the structural integrity of the display. Another option is implementing dual-core LED bulbs, which effectively double the light emission within a single bulb. However, it’s crucial to consider the corresponding increase in power consumption when opting for these high-intensity or dual-core LED solutions.
Improve the Aperture Ratio of TFT Pixels:
aperture ratioit is the ratio of the effective area through which light can pass.When the light is emitted through the backlight panel, not all the light can pass through the panel, such as the signal traces of the LCD source and the gate , as well as the TFT itself. Therefore, only one effective light-transmitting area remains.
By increasing the aperture ratio through design, more light can pass through, thereby increasing the brightness of the LCD display.
Different Architectural Designs and Their Impact on Aperture Ratio:
TN (Twisted Nematic) and IPS (In-Plane Switching) are two display modes that offer different architectural designs. When comparing displays with the same resolution, TN mode displays can achieve a higher aperture ratio. This means that a larger percentage of light can pass through the pixels, resulting in improved brightness and overall display quality.
Different Semiconductor Materials with Varying Transmittance:
The choice of semiconductor materials, such as a-Si (amorphous silicon) and P-Si (polycrystalline silicon), also plays a significant role in determining the aperture ratio. These materials have different structural characteristics, leading to varying levels of light transmission efficiency.
Comparing a-Si and P-Si:
a-Si and P-Si are two distinct types of non-crystalline silicon structures. P-Si exhibits higher electron mobility, enabling the creation of narrower circuits within the display. This narrower circuitry allows for more light to pass through the pixels, leading to increased brightness and improved aperture ratios.
By considering different architectural designs and utilizing semiconductor materials with higher light transmission efficiency, manufacturers can optimize the aperture ratio of TFT pixels. This optimization results in displays that deliver enhanced brightness, improved image quality, and a superior viewing experience for end-users.
However, it is essential to strike a balance between aperture ratio improvements and other factors such as manufacturing costs, power consumption, and production feasibility. By conducting comprehensive research and development, display manufacturers can achieve the ideal balance between performance and practical considerations, ultimately offering high-quality displays that meet the demands of today’s market.
Use Polarizing Films with APF :
APF is a glass reflective polarizing film that transmits one polarization state and reflects the other. By redirecting the reflected light back into the LED backlight, APF effectively improves brightness, especially in wide viewing angles. Combining APF with other brightness enhancement techniques is a commonly used approach in practical applications. Leveraging the benefits of APF can significantly enhance the visual experience for end-users.
Different Bonding Methods and Touchscreens:
The integration of touchscreens with display panels plays a vital role in maintaining optimal brightness and readability. Different integration methods yield varying results in terms of brightness levels and overall display performance. Let’s explore two common approaches:
a. Resistive Touchscreen:
In a resistive touchscreen, the sensor film and air gap between layers can lead to a decrease of approximately 10% in brightness. While resistive touchscreens offer accurate touch detection, their impact on brightness should be taken into account when designing display systems.
b. Optical Bonding with Capacitive Touchscreen:
Optical bonding is considered the optimal choice when integrating capacitive touchscreens. It involves laminating the cover glass or touchscreen with a layer of resin (liquid Optical Clear Resin) or film (dry lamination process with Optical Clear Adhesive). This process reduces light refraction from the LCD backlight and external light sources, thus improving the readability of TFT screens. One of the key advantages of optical bonding is the elimination of air gaps and the two reflective surfaces associated with them.
Use Negative Liquid Crystals:
Traditional LCDs utilize positive liquid crystals. However, the introduction of negative liquid crystals by Merck, a German company, has opened up new possibilities. Compared to positive liquid crystals, negative liquid crystals offer approximately 20% higher brightness. It is important to note that negative liquid crystals have higher viscosity, which can slightly impact response times. Nevertheless, the advantages of increased brightness make it a viable choice for display manufacturers seeking enhanced visual performance.
Adjust Settings and Disable PWM (Pulse Width Modulation):
Disabling the automatic brightness adjustment feature, which relies on pulse width modulation (PWM), can ensure that the display operates at its maximum brightness. By keeping the display consistently bright, even under varying lighting conditions, users can enjoy optimal visual clarity and readability.
Surface Treatment of Cover Lens:
To further improve readability, especially under direct sunlight, applying anti-reflective (AR) and anti-glare (AG) coatings to the cover lens surface can significantly reduce environmental light reflections. These coatings can be directly applied to the LCD or the substrate materials, such as protective cover glass or touch sensors.
AG (Anti-Glare Coating): AG coatings, often described as matte finishes, reduce surface reflections on the LCD panel’s front surface and soften direct light sources. Consequently, the matte surface may have a slight impact on contrast and color vibrancy.
AR (Anti-Reflective Coating): AR films reduce unnecessary surface reflections caused by ambient light, allowing for clear visibility of the screen.
optical alignment technology：
Liquid crystal molecules need to maintain a stable arrangement in the LCD display. This stable arrangement is achieved by the force between polyimide and liquid crystal molecules. By directional rubbing of the polyimide film, the polyimide molecules can be arranged according to the design. Arrangement in a certain direction, while optical alignment (OA) uses polarized light to illuminate special materials to form a consistent direction.
Because friction orientation uses physical friction, debris will be generated during the production process, and because the surface of TFT or CF is uneven, the friction orientation effect is poor, with bright spots and foreign matter defects, and the contrast is also low, usually at 600 : About 1, while OA technology can achieve faster production efficiency and a purer black screen. The contrast ratio of LCD displays using OA technology is usually above 1200:1.
WRGB pixel arrangement：
Usually the pixel arrangement of LCD display is RGB, that is, each pixel contains 3 sub-pixels. In this mode, adding white sub-pixels will obtain the WRGB structure. The white sub-pixels do not have color filters, and there will be very little loss when light passes through. , this will undoubtedly greatly increase the brightness of the display, but there are also certain problems, that is, the number of white sub-pixels and the timing of display need to be reasonably controlled, otherwise the display effect will be reduced. This technology is generally used in large-size LCDs display.
In summary, increasing the brightness of an LCD display offers many benefits, including an enhanced viewing experience, improved readability in various lighting conditions, and improved overall display performance. Displays that excel in brightness, contrast and color reproduction can be obtained by increasing the brightness of the LED backlight unit, changing the lcd panel design, using innovative technologies such as APF, optical bonding, negative liquid crystal, optimizing the display settings, and applying proper surface treatments . Of course it is important to balance brightness improvement with other factors such as power consumption, cost-effectiveness and production feasibility. By considering these aspects, manufacturers can deliver high-quality displays that meet the demands of today’s consumers.