International Business Machines Corporation

Robert Lee Melcher

Evan G Colgan

Kei-Hsiung Yang

Robert J Von Gutfeld

Minhua Lu

Chandrasekhar Narayan

Thomas Mario Cipolla

James L Speidell

James Lawrence Sanford

Frank Benjamin Kaufman

Margaret Paggi Manny

Lubomyr Taras Romankiw

Lawrence Shungwei Mok

Leathen Shi

James McKell Edwin Harper

Norman Steven Shiren

Fuad Elias Doany

Rama Nand Singh

James M Harper

Sheree H Wen

Teruhiro Nakasogi

Frank H Dacol

Thomas Baumann

A reflective spatial light modulator array is described incorporating liquid crystal devices, mirrors, a semiconductor substrate, electrical circuits, and a light blocking layer. The light blocking layer can be a reflector/absorber layer containing titanium. The light blocking layer can be a layer resulting in attenuation of incident light below a certain level at the semiconductor substrate. The invention overcomes the problem of shielding light from semiconductor devices, high optical throughput and contrast, pixel storage capacitance to hold the voltage across the liquid crystal device and precise control of the liquid crystal device thickness without spacers obscuring the mirrors.

Reflective spatial light modulator array including a light blocking layer

A structure (and method) for a reflective-type liquid crystal display includes a first-type electrode, a second-type electrode positioned opposite the first-type electrode and being of an opposite type than the first-type electrode and a liquid crystal material between the first-type electrode and the second-type electrode, wherein at least one of the first-type electrode and the second-type electrode includes an amorphous layer adjacent the liquid crystal material.

Methods of reducing unbalanced DC voltage between two electrodes of reflective liquid crystal display by thin film passivation

Reflective spatial light modulator array is described incorporating liquid crystal devices, mirrors, a semiconductor substrate, electrical circuits, and a reflector/absorber layer for blocking light. The invention overcomes the problem of shielding light from semiconductor devices, high optical throughput and contrast, pixel storage capacitance to hold the voltage across the liquid crystal device and precise control of the liquid crystal device thickness without spacers obscuring the mirrors.

Reflective spatial light modulator array

An optical system for a projection display employing three reflective spatial light modulations (SLM's) is described. Two or the three SLM imaging paths employ typical image combining and projection optical techniques. However, the third SLM imaging path employs a relay lens to produce an intermediate image of the SLM which is subsequently combined with the other two images. Each color component is directed onto one of three SLM's, each through its own polarizing beamsplitter (PBS) cube. In two of the three SLM's, image forming light is reflected from each SLM and passes through its respective PBS, and the two colors are then recombined using a dichroic coating. A lens then images the two-color image, and projects it onto a screens. The third SLM traverses a completely separate path. In this case, the image forming light reflected by the SLM and passing through the PBS is first imaged by a relay lens of approximately unity magnification to produce an intermediate image plane. This intermediate image (of the third colors SLM) is then recombined with the first two color images using PBS or a dichroic coating. The recombination is accomplished in a manner that ensures that the three color images are located at the back focal distance of the projection lens.

Optical system for projection displays using spatial light modulators

A twisted nematic liquid crystal (TNLC) cell used in reflective spatial light modulators (SLMs) of displays is disclosed. The TNLC cell includes front and rear substrates, and a TNLC material having a thickness d and a left-handed or right-handed twist angle .phi.. The TNLC material is sandwiched between the front and rear substrates, and the twist angle .phi. is approximately from 46.degree. to 62.degree.. A direction of directors of the TNLC material located nearest the front substrate forms an initial angle .beta. with a direction of linearly polarized light incident thereon. The initial angle .beta. is approximately from -6.degree. to 60.degree.. A birefringence .DELTA.n of the TNLC material times the thickness d is between approximately 0.7.lambda. to 1.25.lambda., where .lambda. is a wavelength of light incident on the front substrate.

Polarization dependent twisted nematic liquid crystal devices for

A structural principle is described for control of the gap and the area around the periphery of a liquid crystal display by the formation of an insulating layer out of which, gap dimension maintaining posts and contaminant diffusion inhibiting segmented walls, remain after the display area is etched back out of the layer.

Liquid crystal display

A spatial light modulator designed to use a minimum area on the surface of a silicon substrate. This invention comprises a silicon substrate on a back plate with a glass cover that is used to seal liquid crystal between the glass cover and the silicon substrate. Most importantly, the glue seal formed to contain the liquid crystal material is between the cover glass plate and the Si substrate on only one side and the back plate on the remaining three sides. This structure allows a smaller semiconductor substrate to be used.

Substrate structure and assembly method for reduced spatial light

A liquid crystal element, a packaging structure providing thermal and alignment control, a display device including the same, and methods of fabrication and assembly are provided. The liquid crystal element includes: a semiconductor wafer, having microcircuitry and an array of reflective pixels; a layer of electro-optical responsive liquid crystal medium, of uniform thickness, disposed on the reflective pixels; a transparent conductive layer positioned on the liquid crystal, being substantially parallel to the reflective layers, to ensure a uniform thickness of the liquid crystal; and an insulative transparent layer provided on the conductive layer. The liquid crystal element is laminated to an optically flat substrate to limit the out-of-plane distortions thereof. The structure formed by element and substrate are disposed in a substrate holder which is mounted to a wiring board, and coupled to voltage sources for actuating the liquid crystal. During mounting, an aligning fixture is used to ensure proper orientation of the element relative to the related optical elements. Once the element is positioned, a heat sink is coupled to the rear surface of the substrate holder to dissipate heat.

Mechanical packaging and thermal management of flat mirror arrays

A reflective spatial light modulator array is described incorporating liquid crystal devices, mirrors, a semiconductor substrate, electrical circuits, and a reflector/absorber layer for blocking light. The invention overcomes the problem of shielding light from semiconductor devices, high optical throughput and contrast, pixel storage capacitance to hold the voltage across the liquid crystal device and precise control of the liquid crystal device thickness without spacers obscuring the mirrors.

A non-contact thermal imaging system based on infrared radiation detection is described which uses an energy source to provide a beam of energy that strikes a sample to be analyzed. The energy beam produces a thermal wave in the sample, there being infrared radiation emitted from the thermal wave. All of the infrared radiation emitted from the heated area of the sample is collected and directed to an infrared detector, to have a two-dimensional image of the sample. This is used to detect surface and sub-surface structure, defects, etc. The use of a focussed energy beam, such as a laser or electron beam, offers advantages. In this technique, all points of the sample are treated equally and the results are very easily interpreted to know the exact location and type of structure that is imaged in the heated area. An ellipsoidal collector is preferrably used to image the emitted infrared radiation onto the detector, where the sample is located at one focal point of the ellipse, and the detector is located at the other focal point.

Thermal wave microscopy using areal infrared detection

A laser drilling control system utilizing photoacoustic feedback is described. The control system provides an accurate monitoring of the laser drilling of a multilayered printed circuit board thereby allowing uniform drilling through layers of different optical and photoacoustic properties by both analyzing the photoacoustic feedback signals received, and adjusting optimally the laser parameters such as pulse duration, wavelength, energy, pulse repetition rate, and the number of pulses, for each successive layer. The system also provides an end point detection which prevents underdrilling overheating, and overdrilling of underlying layers and associated damages. According to another aspect of this invention, the control system can be used as a sensitive misregistration detector for aligning the laser beam to a selected drill site for subsequent drilling at the selected drill site.

Laser drilling system utilizing photoacoustic feedback

A method for high resolution maskless chemical and electrochemical machining is described. Preferential etching results from exposing those regions where machining is sought to an energy beam. Such exposures can increase the etching rate in the case of electrochemical machining by a factor of 10.sup.3 to 10.sup.4. Such enhancement is sufficient to make masking unnecessary.

Method for maskless chemical machining

A method for high resolution maskless chemical and electrochemical machining is described. Preferential etching results from exposing those regions where machining is sought to an energy beam. Such exposures can increase the ething rate in the case of electrochemical machining by a factor of 10.sup.3 to 10.sup.4. Such enhancement is sufficient to make masking unnecessary.

Method for maskless chemical and electrochemical machining

A method for high resolution maskless electroplating is described. Preferential plating results from exposing those regions where enhanced plating is sought to a collimated energy beam. Such exposure can produce an enhancement in the plating rate of 10.sup.3, which is sufficient to eliminate the necessity of masking the surface.

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Mount Kisco, NY, United States of America

Robert Lee Melcher