Duke University

Compaq Computer Corporation, Inc.

Other

Fusion Lighting, Inc.

Texas Instruments Corporation

Richard M Knox

Dale S Walker

William Burton Mercer

Kevin F Clancy

Austin L Huang

John R Masters

Douglas A Arego

Kevin J Hathaway

Mark W Welker

Stephan A Mato, Jr

Mehdi Zeinali

Gaylon R Kornfuerhrer

Gaylon R Kornfuehrer

Franklin V Barger, Jr

Jefery R Roberts

Wm Michael Miller

Screen apparatuses are provided which include a first lens or holographic optical element layer and a second mask layer. The first layer substantially collimates image light rays to impinge on the mask layer. The mask layer provides an array or matrix of projecting members. Each of the projecting members receives and focuses the substantially collimated light rays to corresponding focal points. The mask layer includes a mask that blocks light transmission except where openings are located. The openings allow the light focused through the focal joints to substantially pass through the mask to form an image. The screen apparatuses can be advantageously employed in display apparatuses.

Projection screen apparatus

In a reflective mode FLC application, a &frac14;-wave plate compensating FLC is used in series with a &frac14;-wave imaging FLC to compensate for the effects of DC balancing. Alternatively, the compensating wave plate could be any odd &frac14;-wave multiple, such as 3&lgr;/4, 5&lgr;/4, etc. The FLCs are driven in synchronization between on and off states with the total effective retardation for each FLC being either none or one-half wavelength in a double pass.

Methods of compensating liquid crystal displays using DC balancing

A light projection engine uses a wide angle reflecting polarizer material (preferably 3M DBEF brand double brightness enhancement filter) as a polarizing beamsplitter to direct polarized light to beam splitter/combiner (such as an X-cube dichroic reflector). The beam splitter/combiner then splits the directed polarized light into separate reflective LCD panels acting as light valves. The LCD panels alter the polarity of the incident light from 0 degrees up to 90 degrees to control which light is passes from the wide angle reflecting polarizer back towards the light source and which light has the necessary polarization change to allow it to pass from the wide angle reflecting polarizer to the lens system. After reflecting off of the LCD panels, the light goes back through the X-cube dichroic reflector, where it is recombined. The recombined light which is of a first polarity is transmitted from the reflecting polarizer to the lens system, while the recombined light which is of a second polarity is transmitted to the light source. The LCDs are preferably analog polarizing LCDs.

Image projection system engine assembly

An &ldquo;extra-folded&rdquo; projection display system includes a selectively reflective material (e.g., a linear reflecting polarizer) placed immediately behind the system's imaging screen. The display system includes an image projector that projects an image beam containing light of a predetermined linear polarization toward the imaging screen. The linear reflecting polarizer reflects the light in the image beam away from the screen. The reflected image beam then encounters a &frac14;-wavelength achromatic retarder which converts the linear polarization to circular polarization. The image beam next hits a mirror that reflects the light back through the &frac14;-wavelength achromatic retarder, which converts the circular polarization back to linear polarization, with the polarization director rotated 90&deg; from the original polarization director. The linear reflecting polarizer then allows the light to pass through to the image screen.

Projecting images

A full color image projection system is provided using two non-color-specific image sources and color-specific filters. The system is capable of projecting an image using one primary color from one image source and the other two primary colors from another image source. The system uses slower speed image sources than would be required with one source alternating between three colors, and exhibits higher resolution than would be obtained from a color-specific image source.

Image engine having multiple image sources with different response times for color operation

In a color sequential system using LCDs, the LCD must operate faster than the frame rate because red, green, and blue are done sequentially. Ferroelectric LCDs can do this, but they are not analog devices and so cannot provide analog display levels. Instead, a pulse width modulation (PWM) technique is used. In the system of the present invention, each pixel has three storage devices to hold RGB analog levels. A latch is used to load these values in parallel. Then an analog 3:1 multiplexer is used to select the proper storage device for the current sequential color. The multiplexer output goes to a comparator, which has a sawtooth waveform input at much faster than the frame rate. The comparator output changes with the sawtooth level, so that PWM control is provided for each pixel. As an alternative, standard analog LCD pixels can be sequentially switched between three color input storage devices.

Multiplexed display element sequential color LCD panel

A display system for a computer includes an image projector located in the computer and oriented to project a computer-generated image from the computer. Alternatively, the display system includes a screen and an image projector attached to the screen, where the screen is capable of receiving a computer-generated image projected by the image projector. Alternatively, the display system includes an image projector and a screen that is attached to the computer and that is capable of displaying an image projected by the image projector.

Projection display for computers

An electro-optic shutter is provided that includes first and second liquid crystal devices located along an optical path and first and second color-selective layers located between the first and second liquid crystal devices. Each liquid crystal device is adapted to rotate the polarization of incident light to a substantially orthogonal polarization in response to being in a first state, and to not substantially change the polarization of incident light in response to being in a second state. The first color-selective layer is adapted to transmit first and second colors and a first polarization of a third color. The second color-selective layer is adapted to transmit the first and the third colors and a second polarization of the second color that is substantially orthogonal to the first polarization. An electro-optic shutter is also provided that includes a color-selective layer, a liquid crystal device to receive light from the color-selective layer and a polarizer to receive light from the liquid crystal layer. The color-selective layer is adapted to transmit a first color, a first polarization of a second color, and a substantially orthogonal polarization of a third color. The liquid crystal device is adapted to rotate the polarization of light to a substantially orthogonal polarization when in a first state and to not substantially rotate the polarization of light when in a second state. The electro-optic shutter can be employed in projection systems.

Separating white light into polarized, colored light

Methods of projecting images

An &ldquo;extra-folded&rdquo; projection display system includes a selectively reflective material (e.g., a linear reflecting polarizer) placed immediately behind the system's imaging screen. The display system includes an image projector that projects an image beam containing light of a predetermined linear polarization toward the imaging screen. The linear reflecting polarizer reflects the light in the image beam away from the screen. The reflected image beam then encounters a &frac14;-wavelength achromatic retarder which converts the linear polarization to circular polarization. The image beam next hits a mirror that reflects the light back through the &frac14;-wavelength achromatic retarder, which converts the circular polarization back to linear polarization, with the polarization director rotated from the original polarization director. The linear reflecting polarizer then allows the light to pass through to the image screen.

A tiled monitor system is implemented with a single controller that does not provide standard video signals to each of the monitors. Instead, only the changed portions of an image to be displayed are sent to the monitors, which internally maintain a video frame buffer for displaying using a display engine. Preferably, a high speed serial link is used between the monitors and the video controller for transmitting this information.

Multi-tile video display system with distributed CRTC

Compensation for DC balancing of liquid crystal displays

An electrodeless lamp (,) for producing an intense beam of light includes a concave lamp body (,) that surrounds the lamp interior. A gas, such as sulfur or selenium or compounds thereof, is contained within the lamp body (,) for forming a plasma light source. The concave lamp body (,) has a reflecting surface (,). Electrodes (,) are disposed external to the lamp body for producing radio frequency energy exciting the gas. A heat resistant glass plate (,) seals the concave lamp body (,). A frit seal (,) can be used for forming a pressure and temperature resistant seal between the concave lamp body (,) and the glass plate (,). The light beam generated by the plasma exists through the glass plate (,).

Electrodeless lamp with sealed ceramic reflecting housing

A polymer dispersed liquid crystal projection display is provided that has enhanced contrast. In the projection system using a polymer dispersed liquid crystal display (PDLC), polarized light is used as the light source onto the PDLC. The reflected light maintains its polarization, while the scattered light from the off pixels of the PDLC randomize the polarization. The polarized image is then passed through a polarizing filter which eliminates half of the scattered light, whereas practically all of the polarized image is passed onto the display source. In this way, the contrast between the on and off pixels is effectively doubled.

Growing community of inventors

Houston, TX, United States of America

Richard M Knox