Abstract: A method for assuring a blazed condition in a DMD device used in telecommunications applications. By meeting certain conditions in the fabrication and operation of the DMD, the device can achieve a blazed condition and be very effective in switching near monochromatic spatially coherent light, thereby opening up a whole new application field for such devices. This method determines the optimal pixel pitch and mirror tilt angle for a given incident angle and wavelength of near monochromatic spatially coherent light to assure blazed operating conditions. The Fraunhofer envelope is determined by convolving the Fourier transforms of the mirror aperture and the delta function at the center of each mirror and then aligning the center of this envelope with a diffraction order to provide a blazed condition.

Abstract: A method for assuring a blazed condition in a DMD device used in telecommunications applications. By meeting certain conditions in the fabrication and operation of the DMD, the device can achieve a blazed condition and be very effective in switching near monochromatic spatially coherent light, thereby opening up a whole new application field for such devices. This method determines the optimal pixel pitch and mirror tilt angle for a given incident angle and wavelength of near monochromatic spatially coherent light to assure blazed operating conditions. The Fraunhofer envelope is determined by convolving the Fourier transforms of the mirror aperture and the delta function at the center of each mirror and then aligning the center of this envelope with a diffraction order to provide a blazed condition.

Abstract: An optical switch ideally suited for use as an optical add drop multiplexer (OADM). A light beam entering the OADM through a first input fiber (402) is separated by wavelength to yield multiple light beams (902, 904). One light beam (902) is reflected by one or more of the mirrors in mirror array (908). Depending on the position of the mirrors struck by light beam (902), the beam is reflected to a first region of a retro-reflector (910) or a second region (912). When light beam (902) is reflected by the second region (912) of the retro-reflector, it again travels to the mirror array (908) and is then reflected to a wavelength combiner (914) and output on the second (“drop”) output fiber (408). While a first wavelength light beam (902) is reflected to the drop output (408), other wavelengths of light from the first input (402), for example light beam (904), are directed to the “out” optical fiber (406).

Abstract: A dichroic spiral color wheel (108) having many spiral-shaped color filters (206). The boundary between adjacent color filters follows the spiral of Archimedes, defined as r=a&thgr;, where r is the radius of the boundary at a given point, a is a constant, and &thgr; is the angle between a radial line through the given point and a reference radial. Using the spiral of Archimedes provides a boundary between adjacent color filters that is nearly parallel to the rows or columns of the modulator and moves across the light path at a constant speed. These two features make the spiral color wheel much more efficient than color wheels having pie shaped segments. The use of dichroic filters, which reflect out of band light is crucial to the operation of a sequential color recycling display system.

Abstract: A family of optical switches. Each switch (400) includes a holder block (402) to hold optical fibers (410, 412) and ferrules (414) in alignment with a micromirror array (406). The holder block 402 has a reflective bottom surface (404). The bottom surface (404) functions as a retro-reflector when the optical switch (400) is assembled. The micromirror array (406) has a substrate on which rows of micromirrors have been fabricated. The ferrules (414) are held at an angle relative to the micromirror array (406). This angle allows the light emitted from the input fiber (410) to traverse the array of micromirrors (406) to the output fiber (412). Light from the input fiber (410) is reflected between a series of mirrors (408) and the retro-reflective surface (404) until reaching the output fiber (412). The rotation of the mirrors determines the path of light across the mirror array (406) and which output fiber (412) the light reaches.

Abstract: An optical switch using an array of mirrors (608) to selectively reflect light from an input fiber (610) to either of a first output fiber (612) or a second output fiber (614). Each fiber is held in a ferrule (616) that aligns the fiber with a focusing device (618). The focusing device associated with the input fiber causes the beam of light to either collimate, diverge, or converge. The focusing device associated with each output fiber collects the beam of light for input into the output fibers. Light from the input fiber (610) strikes a first mirror, or group of mirrors, in the array (608) and is selectively deflected to a second mirror, or group of mirrors, associated with an output fiber (612, 614), by reflecting the beam of light from a retro-reflector (602) between the fibers. The second mirror receives the beam from the retro-reflector (602) and reflects it to the output fiber associated with the second mirror.

Abstract: A frame-addressed bistable micromirror array and method of operation. An analog input signal representing the desired intensity of an image pixel is applied to input 302. An address signal synchronized to the analog input signal is applied to input 304 of a given micromirror cell to store the pixel intensity information on input capacitor 306. After intensity information for each pixel in the video frame or field, or a portion of the frame of field, is stored on the input capacitor 306 of the appropriate micromirror cell, a frame signal is applied to input 308 to enable the transfer of charge between capacitors 306 and 310 and to turn on transistor 314 allowing a voltage applied to input 316 to charge capacitor 318. The pre-charge voltage is chosen to ensure the biased micromirrors are fully deflected to a first state. A ramp voltage is applied to input 322. A ramp voltage is applied to input 322.

Abstract: A method for assuring a blazed condition in a DMD device used in telecommunications applications. By meeting certain conditions in the fabrication and operation of the DMD, the device can achieve a blazed condition and be very effective in switching near monochromatic spatially coherent light, thereby opening up a whole new application field for such devices. This method determines the optimal pixel pitch and mirror tilt angle for a given incident angle and wavelength of near monochromatic spatially coherent light to assure blazed operating conditions. The Fraunhofer envelope is determined by convolving the Fourier transforms of the mirror aperture and the delta function at the center of each mirror and then aligning the center of this envelope with a diffraction order to provide a blazed condition.

Abstract: A wavelength equalizer and method. The wavelength equalizer comprises an input waveguide (302), an output waveguide (322), a wavelength separation device (3 10), and a micromirror array (314). The wavelength separation device (310) divides the input beam of light into sub-beams. A first sub-array of the micromirrors in the micromirror array (314) are operable between a first and second position. The first position directing light in the sub-beam to the output waveguide (322), and the second position excluding the light in the sub-beam from the output waveguide (322). The method of equalizing a plurality of components of an optical input signal comprises: separating the components, directing each component to a sub-array of a micromirror array, positioning micromirrors in each sub-array such that micromirrors in a first position direct incident light to an output waveguide and micromirrors in a second position do not, and combining the sub-beams into an output beam of light.

Abstract: A family of optical switches. Each switch (400) includes a holder block (402) to hold optical fibers (410, 412) and ferrules (414) in alignment with a micromirror array (406). The holder block 402 has a reflective bottom surface (404). The bottom surface (404) functions as a retro-reflector when the optical switch (400) is assembled. The micromirror array (406) has a substrate on which rows of micromirrors have been fabricated. The ferrules (414) are held at an angle relative to the micromirror array (406). This angle allows the light emitted from the input fiber (410) to traverse the array of micromirrors (406) to the output fiber (412). Light from the input fiber (410) is reflected between a series of mirrors (408) and the retro-reflective surface (404) until reaching the output fiber (412). The rotation of the mirrors determines the path of light across the mirror array (406) and which output fiber (412) the light reaches.

Abstract: In an SLM-type display system, a solid state light source can be used to augment a lamp light source in a least two different ways. First, a solid state source can be used to augment deficiencies in a particular spectral region. Typically, lamps are deficient in red, and a red solid state source would be used. However, the same concept applies to augmenting any color region. Multiple solid state sources could be used to augment more than one region. Second, when the SLM system uses a color wheel, a solid state source can be used to eliminate “spoke loss”. Multiple solid state sources can be used for providing different colors during the spokes.

Abstract: In an SLM-type display system, a solid state light source can be used to augment a lamp light source in a least two different ways. First, a solid state source can be used to augment deficiencies in a particular spectral region. Typically, lamps are deficient in red, and a red solid state source would be used. However, the same concept applies to augmenting any color region. Multiple solid state sources could be used to augment more than one region. Second, when the SLM system uses a color wheel, a solid state source can be used to eliminate “spoke loss”. Multiple solid state sources can be used for providing different colors during the spokes.

Abstract: An optical switch ideally suited for use as an optical add drop multiplexer (OADM). A light beam entering the OADM through a first input fiber (402) is separated by wavelength to yield multiple light beams (902, 904). One light beam (902) is reflected by one or more of the mirrors in mirror array (908). Depending on the position of the mirrors struck by light beam (902), the beam is reflected to a first region of a retro-reflector (910) or a second region (912). When light beam (902) is reflected by the second region (912) of the retro-reflector, it again travels to the mirror array (908) and is then reflected to a wavelength combiner (914) and output on the second (“drop”) output fiber (408). While a first wavelength light beam (902) is reflected to the drop output (408), other wavelengths of light from the first input (402), for example light beam (904), are directed to the “out” optical fiber (406).

Abstract: An optical switch using an array of mirrors (608) to selectively reflect light from an input fiber (610) to either of a first output fiber (612) or a second output fiber (614). Each fiber is held in a ferrule (616) that aligns the fiber with a focusing device (618). The focusing device associated with the input fiber causes the beam of light to either collimate, diverge, or converge. The focusing device associated with each output fiber collects the beam of light for input into the output fibers. Light from the input fiber (610) strikes a first mirror, or group of mirrors, in the array (608) and is selectively deflected to a second mirror, or group of mirrors, associated with an output fiber (612, 614), by reflecting the beam of light from a retro-reflector (602) between the fibers. The second mirror receives the beam from the retro-reflector (602) and reflects it to the output fiber associated with the second mirror.

Abstract: A frame-addressed bistable micromirror array and method of operation. An analog input signal representing the desired intensity of an image pixel is applied to input 302. An address signal synchronized to the analog input signal is applied to input 304 of a given micromirror cell to store the pixel intensity information on input capacitor 306. After intensity information for each pixel in the video frame or field, or a portion of the frame of field, is stored on the input capacitor 306 of the appropriate micromirror cell, a frame signal is applied to input 308 to enable the transfer of charge between capacitors 306 and 310 and to turn on transistor 314 allowing a voltage applied to input 316 to charge capacitor 318. The pre-charge voltage is chosen to ensure the biased micromirrors are fully deflected to a first state. A ramp voltage is applied to input 322. A ramp voltage is applied to input 322.

Abstract: A dichroic spiral color wheel (108) having many spiral-shaped color filters (206). The boundary between adjacent color filters follows the spiral of Archimedes, defined as r=a&thgr;, where r is the radius of the boundary at a given point, a is a constant, and &thgr; is the angle between a radial line through the given point and a reference radial. Using the spiral of Archimedes provides a boundary between adjacent color filters that is nearly parallel to the rows or columns of the modulator and moves across the light path at a constant speed. These two features make the spiral color wheel much more efficient than color wheels having pie shaped segments. The use of dichroic filters, which reflect out of band light is crucial to the operation of a sequential color recycling display system.

Abstract: Methods of controlling the illumination source (18) of an SLM-based display system (10). It is assumed that the system (10) displays pixel data formatted into a bit-plane format so that all bits of the same bit-weight can be displayed simultaneously. To provide greyscale, the amplitude of the source (18) may be modulated so that bit-planes having greater bit-weights are displayed with more intense illumination than bit-planes having smaller bit-weights (FIGS. 2 and 3). To avoid visual artifacts, the duty cycle of the bit-plane display times may be shortened relative to the frame period. (FIG. 4A). The latter method can be accompanied by a shortening of the duty time of the illumination on SLM (15). (FIG. 4B). The short duty cycle method may be used together with illumination amplitude modulation, or it may be used with the PWM method of providing greyscale.

Abstract: A forward looking infrared (FLIR) device implemented using complementary metal oxide semiconductor (CMOS) techniques is disclosed. The device includes optics (10) for focusing infrared energy onto a scanner (12) for scanning across a detector array 16; a signal conditioning integrated circuit 18 for producing television compatible video signals from the detector array outputs which are electrical signals representative of the infrared energy impinging thereon; and a monitor (2) for displaying the video signals. The detector array and signal conditioning IC are mounted on a metallized ceramic chip affixed within a DEWAR (19). Electronics (20) ancillary to the signal conditioning IC is located outside the DEWAR.

Abstract: An array of individual elements (10) having reduced control circuitry as compared to existing devices. Sets of elements (11) share a memory cell (12), such that each memory cell (12) has the same fanout as other memory cells (12). Each element (11) in a set is switched to an on or off state via a reset line (13) that is separate from that of the other elements (11) in that set. Data is loaded in split bit-frames during a set time period, such that each split bit-frame contains only the data for elements (11) on one reset line (13). Thus, the same memory cell (12) can be used to deliver data to all elements (11) in its fanout because only one element (11) in the fanout is switched at a time.

Abstract: An improved reticle (20) and method of using it to expose layers of wafers for large integrated circuits (10). The integrated circuit (10) is designed so that nonrepeating patterns are laid out in perimeter areas, distinct from the center area containing contiguous repeating patterns. The reticle (20) is patterned with multiple masks (21-23), with different masks representing the repeating and nonrepeating patterns. The mask (22) representing the repeating pattern may then be stepped and illuminated separately from any mask (21, 23) representing a nonrepeating pattern.