The next-generation display technology is coming up with high-resolution reflective displays. These displays come with motion image capability along with a broad color capability. The reflective displays substantially reduce power consumption, allowing the realization of newer display applications, such as digital textbooks and smartwatches.
E-book applications have been widely using EPD or electrophoretic displays for the past few years. EPDs are low-power displays that form images by the electronic rearrangement of charged pigment particles. However, EPDs are of relatively low reflectivity, as their optical diffusion is essentially Lambertian. Avoiding further reduction in display reflectivity, therefore, requires using narrow color gamut filters, which impacts the display properties negatively.
The use of reflective color liquid crystal displays overcomes this issue of EPDs. Reflective LCDs use a diffusion film and a mirror electrode to diffuse light in its direction of travel. The design of the display system requires a suppression of the chromaticity of the optical components. This establishes a method of controlling the optical diffusion of the reflected light. The net result is a display with high reflectivity and a wide color gamut. This arrangement makes the display optically similar to the white paper.
Sharp makes this low-power, high-resolution reflective display with the technical name IGZO. They offer full color with high-resolution displays, and because of their reflective nature, they are sunlight readable. In fact, their exceptionally high resolution makes them comparable in performance to TFT displays.
Sharp uses unprecedented circuit thinning and transistor miniaturization, leading to a high electron mobility rate. Their design raises the light transmission of each pixel, thereby achieving nearly twice the resolution typically offered by a display of the same transmittance.
IGZO displays achieve power consumption reduction to the order of one-fifth to one-tenth that of conventional displays. This helps to preserve a longer product battery life. Sharp achieves improved pixel performance in their IGZO displays by utilizing a Pause Driving Method that capitalizes on high OFF resistance.
The trend in the electronics industry is towards increasingly thinner and lighter finished products. The IGZO reflective technology meets this demand exceedingly well. This makes IGZO displays ideal for handheld battery-powered products that need full-color, high-resolution displays that perform well in bright outdoor environments. Additionally, the elimination of the backlight opens up the design to a whole new world of possibilities.
The Sharp IGZO reflective displays offer several advantages. The major advantage is they do not require a backlight as they work in a reflective mode, resulting in ultra-low power consumption. The reflective electrode structure results in the displays offering high outdoor readability, with full-color moving images in high contrast. A special design effort from Sharp has resulted in these displays being thin and lightweight. The slim, low-power reflective design enables product design to be made compact.
The IGZO displays support a wide operating temperature range, extending from -20 C to +70 C. Corresponding storage temperatures extend from -30 C to +80 C.
The higher electron mobility of IGZO displays is about 20-50 times faster than those of amorphous silicon displays. This enables them to perform at higher resolution at the same or lower power consumption, as compared to amorphous silicon displays.
