Digitizing projection display
AssigneeNCR Corporation
InventorColin C. Isenman
Life of this patent
Estimating the term…
Abstract
The invention relates to a visual display in which a liquid-crystal matrix generates an image on a screen. (The liquid-crystal matrix acts somewhat like a 35 mm slide.) The screen contains a digitizer which detects the position of a hand-held pointer. The detected position can be reported to a computer, which is involved in generating the image. The screen can be small, as in a notebook computer, or the screen can be as large as a drafting table or chalkboard.
Claims9
In an optical projection system, which (A) contains a liquid-crystal shutter which produces an image in response to electric fields applied to pixels, and which modulates light produced by a light source, and (B) projects the modulated light to a display screen, the improvement comprising:
- a) means for producing a signal indicative of location of a hand-held pointer on the display screen;
- and
- b) a liquid coolant for removing heat from the shutter.
A screen upon which an image may be projected, comprising:
- a) a matte surface along which a user can drag a stylus;
- and
- b) a grid of conductors extending over a substantial part of the screen.
In an optical display containing a liquid-crystal shutter, in which transmissivity of pixels is controlled by application of electric fields to the pixels, and a light source for illuminating the shutter, the improvement comprising:
- a) a filter between the light source and the shutter which blocks infra-red radiation from the shutter;
- and said light source containing:
- b) a filament;
- c) a dichroic reflector which
- i) receives light from the filament and
- A) rejects infra-red light from the received light and
- B) reflects visible light toward the shutter;
- and
- ii) receives infra-red light reflected by said filter, and rejects at least part thereof.
A video display, comprising:
- a) an image generation system which includes:
- i) a light source;
- ii) a modulator for modulating the light source, on a pixel-by-pixel basis;
- iii) a screen for displaying the modulated light;
- and
- iv) a holographic diffuser associated with the screen;
- and
- b) means for detecting position of a hand-held pointer on the screen.
A video display, comprising:
- a) a shutter, comprising polymer-dispersed liquid crystal material;
- b) a light source for projecting light through the shutter;
- and
- c) a screen for displaying light received from the shutter;
- and wherein no substantial attenuation of light occurs because of polarizing filters associated with the shutter.
An optical projection system, comprising:
- a) a liquid-crystal shutter, in which transmissivity of pixels is controlled by application of electric fields;
- b) a light source for projecting light through the shutter;
- c) a display screen on which the projected light produces an image;
- and
- d) a plurality of conductors associated with the display screen, for use in detection of position of a stylus;
- and wherein no phase change of liquid crystal occurs during normal operation.
Dependencies are inferred from the claim text.