Lcos Technology
ABSTRACT OF LCOS DISPLAY
Modern display technology has made it generally easier and cheaper to create complex visual stimuli than was possible with the older optical systems. However, all of the display types in widespread use have significant limitations. Common CRT displays are inexpensive, have reasonably good spatial and temporal resolution, and reasonably high contrast, but are dim. LCD projectors are brighter, but suffer from low contrast. One-chip micromirror (DLP) devices that temporally cycle through three primaries are inexpensive but suffer from color ghosting problems with eye movements, and three-chip versions are very expensive; worse, there are control issues with both DLP types. A newer technology that offers much promise is the Liquid Crystal On Silicon (LCOS) display, based upon a reflective rather than transmissive liquid crystal. Here we characterize a particular LCOS projector, the JVC DLA-SX21, in terms of its suitability as a display for vision research. Built into a simple rear-projection optical system, the projector produces high light levels. It also produces stimuli of reasonably high contrast, and has a good color gamut. Although the projector accepts a wide range of frame rates of input signals, its on-board processor resamples the signal to produce an output that is always at 60 Hz, limiting its temporal performance. However, this projector is a compelling choice as a stimulus display for applications that do not need high frame rates. LCOS technology will likely prove a useful addition to the vision scientist's armamentarium.
Introduction
Liquid crystal on silicon (LCoS or LCOS) is a "micro-projection" or "micro-display" technology typically applied in projection televisions. It is a reflective technology similar to DLP projectors; however, it uses liquid crystals instead of individual mirrors. By way of comparison,LCD projectors use transmissive LCD chips, allowing light to pass through the liquid crystal. In LCoS, liquid
Modern display technology has made it generally easier and cheaper to create complex visual stimuli than was possible with the older optical systems. However, all of the display types in widespread use have significant limitations. Common CRT displays are inexpensive, have reasonably good spatial and temporal resolution, and reasonably high contrast, but are dim. LCD projectors are brighter, but suffer from low contrast. One-chip micromirror (DLP) devices that temporally cycle through three primaries are inexpensive but suffer from color ghosting problems with eye movements, and three-chip versions are very expensive; worse, there are control issues with both DLP types. A newer technology that offers much promise is the Liquid Crystal On Silicon (LCOS) display, based upon a reflective rather than transmissive liquid crystal. Here we characterize a particular LCOS projector, the JVC DLA-SX21, in terms of its suitability as a display for vision research. Built into a simple rear-projection optical system, the projector produces high light levels. It also produces stimuli of reasonably high contrast, and has a good color gamut. Although the projector accepts a wide range of frame rates of input signals, its on-board processor resamples the signal to produce an output that is always at 60 Hz, limiting its temporal performance. However, this projector is a compelling choice as a stimulus display for applications that do not need high frame rates. LCOS technology will likely prove a useful addition to the vision scientist's armamentarium.
Introduction
Liquid crystal on silicon (LCoS or LCOS) is a "micro-projection" or "micro-display" technology typically applied in projection televisions. It is a reflective technology similar to DLP projectors; however, it uses liquid crystals instead of individual mirrors. By way of comparison,LCD projectors use transmissive LCD chips, allowing light to pass through the liquid crystal. In LCoS, liquid