Abstract: 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.

Abstract: An electrodeless lamp (10) for producing an intense beam of light includes a concave lamp body (11) that surrounds the lamp interior. A gas, such as sulfur or selenium or compounds thereof, is contained within the lamp body (11) for forming a plasma light source. The concave lamp body (11) has a reflecting surface (12). Electrodes (27, 28) are disposed external to the lamp body for producing radio frequency energy exciting the gas. A heat resistant glass plate (20) seals the concave lamp body (11). A frit seal (23) can be used for forming a pressure and temperature resistant seal between the concave lamp body (11) and the glass plate (20). The light beam generated by the plasma exists through the glass plate (20).

Abstract: 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.

Abstract: A screen apparatus includes a holographic optical element and a diffuser. The holographic optical element may be constructed using standard techniques known in the field of holography. The holographic optical element may be used to replace a typical Fresnel lens used in projection screen apparatuses. In operation, the holographic optical element receives image light from an image engine or projector and redirects the image light to the diffuser for scattering. The holographic optical element can be designed to substantially collimate. converge, or diverge the image light. The combination of the holographic optical element and the diffuser provides improved illumination uniformity that can be perceived by a viewer as the viewer moves in directions transverse to the screen apparatus. The screen apparatus may be designed to provide improved illumination uniformity to optimized or optimal locations in a viewing region. The screen apparatus may be advantageously employed in display apparatuses.

Abstract: Projection lenses and projection lens systems are telecentric between an illumination subsystem and a set of imagers. The lenses and systems can exhibit color fringing correction, uniform imager illumination, athermalization, and component articulation for improved imaging. The lenses and systems may be employed in display apparatuses, such as folded display apparatuses that have decreased footprint size, but long effective projection lengths.

Abstract: 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.

Abstract: A lamp apparatus for producing a beam of light that can be used as a part of a source for a projection system. The lamp apparatus of the present invention produces a beam of light originating from a small aperture. The apparatus includes an electrodeless lamp body in the form of elongated outer tube having a hollow interior. An inner sleeve fits or is deposited inside the outer tube, the inner sleeve having a fill containing generally cylindrically or spherical shaped bore. The sleeve provides temperature resistant and reflection properties. Electrodes positioned either internally or externally of the lamp body are provided for producing radio frequency energy that excite the fill contained in the bore of the inner sleeve to form a plasma light source of intense heat. The light thus generated by the plasma in a relatively large volume is constrained to exit through a small aperture at either one, or both, ends of the apparatus.

Abstract: A lamp apparatus includes an electrodeless bulb that includes a chamber, a gas contained within the chamber in the bulb, and at least one reflector electrode adjacent the bulb for transmitting radio-frequency electromagnetic energy to the gas in the bulb to excite the gas and cause it to radiate light and for reflecting the light radiated from the bulb. Preferably, there are two reflectors electrodes. The bulb can advantageously be made of a tube, in which case the reflectors electrodes can be made shorter than the bulb and centered thereon so that the intense heat caused by the plasma when the gas is excited does not reach the ends of the bulb.

Abstract: An electrodeless lamp apparatus of high efficiency employs a reflection system that allows the lamp to reabsorb light energy. The energy is redirected back to the light to provide increased system efficiency. The redirected light is of the wrong polarization and/or wrong parts of the color spectrum. The lamp efficiency is increased because of the optical pumping as well as the reuse (after some downshifting) of the returned light. In one embodiment, a projection system provides an image source or projection engine that includes the improved high efficiency lamp of the present invention.

Abstract: Light sources include an electrodeless bulb having an interior, a fill contained within the interior of the bulb, an excitation structure that transmits electromagnetic energy to the fill in the bulb, and cooling fins extending radically outward from the bulb. The fill is excited by the electromagnetic energy to a plasma state that causes light emission and generates heat energy. The cooling fins, when rotated, draw air toward the bulb to cool the bulb. Alternatively, cooling may be provided by a rotatable squirrel cage about an electrodeless bulb. The light sources can be used in display systems, such as field sequential color systems.