Pixel density

Abstract: Multiview three-dimensional (3D) displays can project the correct perspectives of a 3D image in many spatial directions simultaneously They provide a 3D stereoscopic experience to many viewers at the same time with full motion parallax and do not require special glasses or eye tracking None of the leading multiview 3D solutions is particularly well suited to mobile devices (watches, mobile phones or tablets), which require the combination of a thin, portable form factor, a high spatial resolution and a wide full-parallax view zone (for short viewing distance from potentially steep angles) Here we introduce a multi-directional diffractive backlight technology that permits the rendering of high-resolution, full-parallax 3D images in a very wide view zone (up to 180 degrees in principle) at an observation distance of up to a metre The key to our design is a guided-wave illumination technique based on light-emitting diodes that produces wide-angle multiview images in colour from a thin planar transparent lightguide Pixels associated with different views or colours are spatially multiplexed and can be independently addressed and modulated at video rate using an external shutter plane To illustrate the capabilities of this technology, we use simple ink masks or a high-resolution commercial liquid-crystal display unit to demonstrate passive and active (30 frames per second) modulation of a 64-view backlight, producing 3D images with a spatial resolution of 88 pixels per inch and full-motion parallax in an unprecedented view zone of 90 degrees We also present several transparent hand-held prototypes showing animated sequences of up to six different 200-view images at a resolution of 127 pixels per inch

Abstract: An image sensor comprised of an array of photo elements (pixels) includes a device for randomly addressing individual pixels and a device for selectively varying the number of pixels which can be read out on any one reading cycle. The random addressing of pixels enables the readout of pixels located in selected regions of interest. Limiting the readout of the images to areas of interest allows an increase in the frame rate of the images. Relatively large groups of pixels can be read out simultaneously and the resulting signals can be merged into superpixel signals to provide high speed data capture, albeit at relatively lower resolution, since there will be a reduced number of data samples in each image. This feature is useful to rapidly scan and analyze a scene being viewed in order to locate an area of interest. Once an area of interest is located, the number of pixels read out on each cycle may be reduced to provide a higher resolution, lower speed, readout of the area of interest.

Abstract: Optical metasurfaces are starting to find their way into integrated devices, where they can enhance and control the emission, modulation, dynamic shaping, and detection of light waves. In this study, we show that the architecture of organic light-emitting diode (OLED) displays can be completely reenvisioned through the introduction of nanopatterned metasurface mirrors. In the resulting meta-OLED displays, different metasurface patterns define red, green, and blue pixels and ensure optimized extraction of these colors from organic, white light emitters. This new architecture facilitates the creation of devices at the ultrahigh pixel densities (>10,000 pixels per inch) required in emerging display applications (for instance, augmented reality) that use scalable nanoimprint lithography. The fabricated pixels also offer twice the luminescence efficiency and superior color purity relative to standard color-filtered white OLEDs.

Abstract: A visual prosthesis for the blind using electrical stimulation of the visual cortex will require the development of an array of electrodes Passage of current through these electrodes is expected to create a visual image made up of a matrix of discrete phosphenes The quality of the visual sense thus provided will be a function of many parameters, particularly the number of electrodes and their spacing We are conducting a series of psychophysical experiments with a portable “phosphene” simulator to obtain estimates of suitable values for electrode number and spacing The simulator consists of a small video camera and monitor worn by a normally sighted human subject To simulate a discrete phosphene field, the monitor is masked by an opaque perforated film The visual angle subtended by images from the masked monitor is 17° or less, depending on the mask, and falls within the fovea of the subject In the study presented here, we measured visual acuity as a function of the number of pixels and their spacing in the mask Visual acuity was inversely proportional to pixel density, and trained subjects could achieve about 20/26 visual acuity with a 1024 pixel image We conclude that 625 electrodes implanted in a 1 cm by 1 cm area near the foveal representation of the visual cortex should produce a phosphene image with a visual acuity of approximately 20/30 Such an acuity could provide useful restoration of functional vision for the profoundly blind