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Input and Output Devices
Published in Julio Sanchez, Maria P. Canton, Embedded Systems Circuits and Programming, 2017
Julio Sanchez, Maria P. Canton
Depending on the positioning of the light source, an LCD can be either transmissive or reflective. A transmissive LCD is illuminated from the back and viewed from the front. This type is common in applications that require high levels of illumination, as is the case with computer displays and television sets. Reflective LCDs, on the other hand, are illuminated by an external source. This type finds use in digital watches and calculators. Reflective technology produces a darker black color than the transmissive type, as light is forced to pass twice through the liquid crystal layer. Because reflective LCDs do not require a light source they consume less power than the transmissive ones. A third type, called transflective LCDs, works either as a transmissive or a reflective LCD, depending on the ambient light.
Liquid crystal displays
Published in John P. Dakin, Robert G. W. Brown, Handbook of Optoelectronics, 2017
There remain several display markets where no display technology has yet delivered, whether LCD or alternative. Although reflective color and transflective displays have been marketed, solutions to date have not been adequate to gain market acceptance. LCDs have a natural advantage for transflective mode operation, being based on transparent media that modulates ambient light. Electrophoretics absorb light preventing transmissive operation and OLEDs emit and so cannot modulate reflected light. Solutions to achieving the required performance at a suitably low cost have yet to be commercialized; perhaps the developments of new nematic modes [e.g., 180] or the application of a new LC phase, such as the blue phase III [205], will prove successful.
Electro-optic Ceramics and Devices
Published in Lionel M. Levinson, Electronic Ceramics, 2020
PLZT devices are very simple in construction, generally consisting of an electroded plate sandwiched between two crossed or parallel polarizers oriented at 45° to the electrode direction. The arrangement for a transmissive (back-lit) device is illustrated in Fig. 33A. For a front-lit, reflective device, a diffuse solid reflector is placed behind the second polarizer. Transflective devices employ a semitransmissive (≃30% transmissive and 70% reflective) diffuse reflector with both front and back lighting for both day and night viewing.
Transflective blue-phase liquid crystal display with dielectric protrusion
Published in Liquid Crystals, 2019
Li-Lan Tian, Fan Chu, Hu Dou, Lei Li, Qiong-Hua Wang
Transflective liquid crystal display (TR-LCD) is attractive for its desirable sunlight readability outdoors and low power consumption. BPLC has been considered for single-cell-gap and double-cell-gap sequential TR-LCDs [18–22]. In this paper, we propose a single-cell-gap TRBP-LCD with dielectric protrusions fixed on the IPS electrodes. To balance the optical phase retardation between the transmissive (T) and reflective (R) regions and obtain well-matched VT and VR curves, we intentionally design the T and R regions to have different heights of the dielectric protrusions. This display exhibits a reasonable high transmittance while keeping a low operating voltage compared with the conventional IPS structure. What is more, it could also achieve a wide viewing angle and submillisecond response time.
Step-shaped electrode for low-voltage and high-optical-efficiency blue-phase transflective liquid crystal displays
Published in Liquid Crystals, 2019
In recent years, mobile and wearable devices have become popular. For these devices, transflective LCD (TR-LCD) is an important and attractive display mode as they can provide very low power consumption and allow much better outdoor readability under strong sunlight [8,9]. In these displays, the pixel is divided into transmissive T and reflective R regions. The T region uses backlight whereas R region uses ambient light for displaying the image. Recently, many researchers have proposed TR-LCDs that are based on PSBP liquid crystals [10–17]. However, without suitable electrode designs, these PSBP TR-LCDs tend to require high operation voltage V and have low light efficiency. Moreover, in TR-LCDs, matching of electro-optic curves for T and R is required since reflected light transverses the cell gap twice, whereas transmitted light transverses the cell gap only once.