Transparent Liquid Crystal Display Research Articles

Perception-Driven Soft-Edge Occlusion for Optical See-Through Head-Mounted Displays.

Systems with occlusion capabilities, such as those used in vision augmentation, image processing, and optical see-through head-mounted display (OST-HMD), have gained popularity. Achieving precise (hard-edge) occlusion in these systems is challenging, often requiring complex optical designs and bulky volumes. On the other hand, utilizing a single transparent liquid crystal display (LCD) is a simple approach to create occlusion masks. However, the generated mask will appear defocused (soft-edge) resulting in insufficient blocking or occlusion leakage. In our work, we delve into the perception of soft-edge occlusion by the human visual system and present a preference-based optimal expansion method that minimizes perceived occlusion leakage. In a user study involving 20 participants, we made a noteworthy observation that the human eye perceives a sharper edge blur of the occlusion mask when individuals see through it and gaze at a far distance, in contrast to the camera system's observation. Moreover, our study revealed significant individual differences in the perception of soft-edge masks in human vision when focusing. These differences may lead to varying degrees of demand for mask size among individuals. Our evaluation demonstrates that our method successfully accounts for individual differences and achieves optimal masking effects at arbitrary distances and pupil sizes.

Low-crosstalk 3D display without color moiré patterns based on a color light source array.

A low-crosstalk 3D display without color moiré patterns based on color light source array is proposed. The proposed 3D display consists of a color light source array, a transparent liquid crystal display (T-LCD) panel, a scattering layer, and a parallax barrier from back to front. The color light source array consists of three primary color light sources that correspond to the sub-pixels on the T-LCD panel. These light sources project the sub-pixels with matching color to the same location on the scattering layer to form new pixels without color moiré patterns. The new pixels have inter-pixel gaps that enhance signal bandwidth and decrease crosstalk. The parallax barrier projects the new pixels of parallax images to different viewpoints, creating a 3D effect. A prototype is developed and evaluated.

P‐4.2: Study on Optical Performances of Transparent LCD with Dichroic Dye‐doped Liquid Crystal

With the development of the Internet of Things, transparent display is playing an increasingly important role in people's lives. The most important optical index of transparent display is transmittance. Due to no need for polarizer, transparent liquid crystal display (TLCD) with dichroic dye‐doped can achieve very high transmittance. In this paper, optical performance and image quality improvement of TLCD with dye‐doped liquid crystal were studied. A new TN pixel design with common electrode of ITO instead of metal to form stored capacitance was used to achieve high aperture ratio (AR). And it was found that bright transmittance of NWSC is higher than that of NBSC due to high anchoring effect of PI to positive liquid crystal. In addition, the transmittance decreases gradually with increasing cell gap due to the increased light absorption by the long axis of dye molecules. The results showed that the TLCD with Dichroic Dye‐doped Liquid Crystal (DDLC) has a good display effect.

38‐2: Invited Paper: 12.3‐in Highly Transparent LCD by Scattering Mode with Direct Edge Light and Field‐Sequential Color‐Driving Method

We have newly developed 12.3‐inch highly transparent color liquid crystal display (LCD) which has no color filter, no polarizer and no back light. For the improvement of optical performance and lager sized panel, the process of scattering liquid crystal, panel structure and driving scheme were optimized. We have successfully achieved high transmittance as 87% and high contrast ratio as 32:1 which is 2 times larger than previous 4‐inch model.

Real-time viewpoint generation-based 3D display with high-resolution, low-crosstalk, and wide view range

A real-time viewpoint generation-based 3D display with low crosstalk and high resolution is proposed. The proposed 3D display consists of a pattern image display (PID), a lenticular lens, and a transparent liquid crystal display (LCD) panel. For each eye of the observer, the PID can provide a pattern image with stripes that have a calculated pitch and displacement according to the eye position. The light from the stripes can be concentrated 3D display eye tracking by the lenticular lens and generate a viewpoint at the eye position. The transparent LCD panel is used to provide parallax images. This transparent LCD panel will not change the direction of light propagation and the location of the generated viewpoints. Then the whole parallax image on the transparent LCD panel can be projected by the PID and the lenticular lens to the viewpoint, so the resolution will not suffer like that in the convention 3D displays. Because the viewpoints are real-time generated according to the position of the observer’s eyes, the observer’s eyes will completely coincide with the position of the generated viewpoint. So crosstalk can be limited at a low level, and the viewing range is almost unlimited.

High-Luminance Mid-Air Image Display for Outdoor Viewing by Focusing Sunlight

The mid-air image is a very powerful method for presenting computer graphics in a real environment, but it cannot be used in bright locations owing to the decrease in brightness during the imaging process. Therefore, to form a mid-air image with a high-brightness light source, a square pyramidal mirror structure was investigated, and the sunlight concentration was simulated. We simulated the tilt angle and combination angle of the condenser as parameters to calculate the luminance of the surface of a transparent liquid crystal display. The light collector was installed at 55∘ from the horizontal plane and mirror. A high level of illumination was obtained when these were laminated together at an angle of 70∘. To select a suitable diffuser, we prototyped and measured the brightness of the mid-air image with an LED lamp to simulate sunlight in three settings: summer solstice, autumnal equinox, and winter solstice. The maximum luminance of the mid-air image displayed by collecting actual sunlight was estimated to be 998.6 cd/m2. This is considerably higher than the maximum smartphone brightness to allow for outdoor viewing, and it can ensure fully compatible visibility.

Large transparent display based on liquid crystal technology.

A large transparent liquid crystal display (LCD) prototype with ultrahigh transmittance and good see-through property is demonstrated in this paper. The transmittance reaches more than 20% by introducing the RGBW pixel arrangement, a thin color filter process, a large aperture ratio design, as well as antireflective polarizer film. The see-through image quality is also greatly improved by suppressing the blurring by using domain reduction pixel design. All these approaches are applicable for large LCD panel products, and we expect broad applications of large transparent LCDs in the near future.

Flat-Panel See-Through Three-Dimensional Display Based on Integral Imaging Using a Transparent Polarized Point Light Source Array

This study proposes a technique to implement see-through three-dimensional (3-D) display based on point light source integral imaging. This display consists of an edge-lit light guide plate, a polarizer array, and a transparent liquid crystal display (LCD) panel without rear polarizer. The combination of the light guide plate and the polarizer array act as a transparent polarized point light source array (PLSA), and reconstructs the 3-D image with the elemental image array loaded on the LCD panel. The background rays passing through the gaps in the polarized PLSA carry the object information and implement see-through property. The experimental system is constructed based on 1-D integral imaging to verify the proposed method. The see-through and superposition capabilities of the proposed method are demonstrated.

透明、白、黒表示が可能な透明液晶ディスプレイ(ディスプレイ材料・製造技術シンポジウム)

透明、白、黒表示が可能な透明液晶ディスプレイ(ディスプレイ材料・製造技術シンポジウム)

Color Transparent Display Using Polymer-Dispersed Liquid Crystal

We have developed a 11.4-inch color active-matrix thin-film transistor (TFT) transparent liquid crystal display (LCD) by using polymer-dispersed liquid crystal (PDLC) technology. The resolution of color transparent LCD was designed to wide screen video graphics array (WSVGA) and the pixel per inch (PPI) is 104. Then, the transmittance of the color transparent LCD can achieve upward 15%. In this paper, the color transparent display has some advantages, such as, good visibility, high transparency, polarizer free, backlight less (environmental light only), and so on.

LCD-based digital eyeglass for modulating spatial-angular information.

Using programmable aperture to modulate spatial-angular information of light field is well-known in computational photography and microscopy. Inspired by this concept, we report a digital eyeglass design that adaptively modulates light field entering human eyes. The main hardware includes a transparent liquid crystal display (LCD) and a mini-camera. The device analyzes the spatial-angular information of the camera image in real time and subsequently sends a command to form a certain pattern on the LCD. We show that, the eyeglass prototype can adaptively reduce light transmission from bright sources by ~80% and retain transparency to other dim objects meanwhile. One application of the reported device is to reduce discomforting glare caused by vehicle headlamps. To this end, we report the preliminary result of using the reported device in a road test. The reported device may also find applications in military operations (sniper scope), laser counter measure, STEM education, and enhancing visual contrast for visually impaired patients and elderly people with low vision.

Polymer-Dispersed Liquid Crystal Applied in Active-Matrix Transparent Display

In this paper, we have developed an active-matrix thin-film transistor (TFT) transparent liquid crystal display (LCD) by using polymer dispersed liquid crystal (PDLC) technology. Also, there are some advantages, such as being polyimide-less, polarizer-free, environmental-light only, and so on. In addition, their transmittance of the transparent state is upward 40%, the transmittance of the scattering state is under 3%, and the driving voltage is under 6 V. The transparent display has high transparency, good visibility, and low electric consumption.