Type of LCD Mode
Transmissive LCD Display
The transmissive display module is simply composed of a backlight and display panel. The display panel cannot emit light and relies on the stable light source provided by the backlight.
Most transmissive displays are suitable in indoor and low-light environments and are also used in applications that pursue high-quality and high-resolution images, and videos, that is why most TFT LCDs are commonly in transmissive display mode.
Reflective LCD Display
The reflective display, as its name implies, is designed to reflect ambient light to illuminate the screen and create visible images. It relies on the principle of reflection, where light incident on the display surface is reflected back to the viewer’s eyes.
Reflective LCDs are mainly used outdoors and indoors with good lighting. Since this display does not require the backlight, it’s thinner and has lower power consumption, however, it comprises the imaging quality, and some small handheld devices use this technology.
Transflective LCD Display
In between, Transflective LCD displays combine the benefits of transmissive and reflective ones, making them equally readable in bright sunlight and low-light conditions.
Figure 1. Three types of LCD display modes
Structure of Transflective Display
The secret of the transflective display is the transflective film. Just like the glass on some buildings, the front is a mirror（which can reflect sunlight and provide a light source for reading in the sun); while the back of the mirror can see through the mirror（providing a channel for the screen backlight）.
A pixel unit of transflective display is divided into a transmission area and a reflection area. When the ambient light is dark, the light from the backlight passes through the transmission area and enters the transmissive display mode. When the ambient light is bright, the backlight is turned off, and the external light is reflected in the reflective area.
Figure 2. The structure of a transflective LCD display
Advantage
Visibility in Bright Sunlight
Transflective displays use ambient light to reflect images, making them more visible than other display technologies.
Low power consumption
Transflective LCD displays use ambient light to reflect images, reducing the need for the backlight, which consumes less power than other display technologies. This makes them ideal for portable devices that require longer battery life.
Improve the Durability
The reflective layer of the transflective LCD screen can protect the screen from damage.
More Comfortable to the Eyes
In addition, since the transflective screen not only emits its own light but also uses external light, even looking at this screen for a long time, the eyes are not tired like the transmissive screen.
Drawback
Of course, this display mode not as popular as the transmissive way is for reasons:
Limited Brightness and Color
Transflective displays may not achieve the same brightness and color vibrancy as purely transmissive displays, especially when used indoors. This is because they rely on ambient light for reflection.
Complex Design
Transflective displays require a complex design that combines reflective and transmissive elements. This complexity can make them more challenging and expensive to manufacture compared to simpler display technologies.
Viewing Angle Limitations
While transflective displays are designed to improve visibility in outdoor conditions, they may still have limitations in terms of viewing angles. The angle of the incident light can influence the effectiveness of the reflective layer.
Cost
Implementing a transflective display can be more expensive than using a standard transmissive display technology. The additional layers and components needed to achieve the reflective and transmissive properties contribute to the overall cost.
Trade-Offs in Power Consumption
While transflective displays can be more power-efficient in certain lighting conditions due to their reliance on ambient light, the trade-off is that they may consume more power when used in dark or low-light environments where the backlight needs to compensate.
Complexity in Adjustment
Achieving the optimal balance between reflective and transmissive elements may require more sophisticated control systems. This complexity can make it challenging to fine-tune the display for different lighting conditions.
Summary
Considering the features of the transflective LCD displays, they are still more commonly used in industrial and medical equipment, as they allow for lower power consumption in bright environments and provide readability in any lighting condition.
Above is the introduction to the principle and structure of transflective TFT LCD. For more display knowledge, please contact Tailor Pixels.
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