We previously studied methods leveraging pixel-level visible light communication (PVLC) that embeds imperceptible information for human eyes in each pixel of an image. The PC computation load and amount of data transferred between the PC and projector in previous PVLC systems were excessive because the PC executed both the video and data encoding processes. As a result, it was impossible to achieve both high-dynamic-range images and dynamic updates of the images and data. In this paper, we propose a dynamic PVLC system that offers high video quality and interactively updates the PVLC information through hardware encoding processing. Our system can project a 24-bit gradation color PVLC video that contains 64-bit data at 120 fps by synchronously controlling the ON/OFF states of the DMD and LED light sources at the given performance limit of the projector.
We have developed a fast switching twisted-vertically aligned (TVA)-mode reflective liquid crystal display (LCD) using a mortar-shaped pixel structure. We realized an axially symmetric pretilt angle in each pixel using the mortar-shaped pixel structure fabricated using UV pattern exposure. We experimentally confirmed that the axis-symmetric alignment from the mortar-shaped structure controls the start point of the alignment change in the voltage-on state over the entire surface of the pixel region, and is effective in improving the response speed of the TVA-mode LCD.
The addition of a UV absorber to the resin prior to curing was examined as a means of controlling the internal polymer structure and refractive index distribution of an anisotropic light diffusing film. The bending of columnar polymer structures inside the film could be controlled by the amount of UV absorber and the UV irradiation conditions. Light diffusing films with bent polymer structures exhibited wide diffusion areas. When applied to reflective displays, the range of incident angles wherein ambient light is diffused was significantly larger.
We measured the thickness of the LC layer of flexible liquid crystal displays (LCDs) in non-curved and curved states and evaluated a capability to maintain the thickness of the LC layer of flexible LCDs with bonding polymer spacers. We found that both the rigid spacers suppressing a compressive force and the spacers bonding two substrates were required to maintain the thickness of the LC layer of curved LCDs. We developed the composite spacer structure using the columnar photo spacer and the bonding polymer spacer; these maintained a constant thickness of LC layer over the entire liquid crystal cell and will improve the contrast ratio of flexible LCDs even in a small radius of curvature.
We report the novel low-temperature fabrication method of an interdigitated spacer structure for flexible liquid crystal displays. An interdigitated structure was fabricated on a polycarbonate substrate in the absence of any thermal process. Liquid crystal cells having curvature radius of 25mm had good flex durability.