Abstract: A micromirror capable of analog pulse width modulation, and method thereof. A capacitor (406) in each micromirror element stores a charge representative of one pixel of image data. A comparator (414) compares the image data signal stored on the capacitor (406) to a reference signal from a reference signal generator (416). Depending on the results of the comparison, the address electrodes (418) of the micromirror are biased to deflect the micromirror (412). As either the image data charge stored on the capacitor (406), or the reference voltage changes, the output of the comparator (414) changes to alter the position of the micromirror (412).

Abstract: A micromirror capable of analog pulse width modulation, and method thereof A capacitor (406) in each micromirror element stores a charge representative of one pixel of image data. A comparator (414) compares the image data signal stored on the capacitor (406) to a reference signal from a reference signal generator (416). Depending on the results of the comparison, the address electrodes (418) of the micromirror are biased to deflect the micromirror (412). As either the image data charge stored on the capacitor (406), or the reference voltage changes, the output of the comparator (414) changes to alter the position of the micromirror (412).

Abstract: A sequential color display system using three spatial light modulators and dichroic filters to sequentially provide a primary color light beam to a projection spatial light modulator. A set of dichroic filters separates a white light beam into primary colored light beams. Each primary colored light beam is modulated by a spatial light modulator to selectively allow it to travel to a second set of dichroic filters. The second set of dichroic filters recombines the primary color light beams—only one of which is typically active at any given time—to form a sequential color light beam. A projection spatial light modulator selectively modulates the sequential color light beam to form a sequential color image projected onto an image plane.

Abstract: A new method for phase locking the color wheel in a color field-sequential projection display. At periodic interrupts, the method determines which color wheel index mark should be driven into coincidence with the Vsync signal. It does this by measuring the delay between Vsync and any index mark and then based on the current state of the spoke-sync counter and this delay value, a new next state is determined to drive the nearest index mark to Vsync to the Vsync position. At worst case this technique requires only one-half a color wheel revolution of phase correction to re-lock the system when the TV channel is changed and for the 5/2 and 7/2 spoke-sync modes, popular 50 Hz and 60 Hz modes, only one-quarter revolution of phase correction of the color wheel is required for re-lock.

Abstract: An image data control unit for an SLM-based photofinishing system. The control unit is typically used with a photofinishing system in which the SLM provides an exposure region that is smaller than the image to be printed or otherwise produced. Thus, the output image is in motion relative to the SLM, such as by moving the photographic medium under the SLM. To meet system throughput requirements, such systems use an exposure algorithm that exposes each line of the output image with multiple rows of the SLM. The control unit implements the exposure algorithm by reformatting source image data and loading the SLM with SLM settings. It synchronizes these functions to the motion of the photographic medium upon with the image is printed.

Abstract: An SLM-based video receiver (10) receives a video input of some standardized format at a signal interface unit (11) and passes the input to a processor (12). The processor (12) performs analog-to-digital conversion if the pixel data is analog and also performs other enhancements to prepare the pixel data for loading into a video memory (14). The pixel data from the processor (12), representing a field of pixel data, is stored into the memory (14) for loading into rows of pixel elements of a spatial light modulator (16). The spatial light modulator (16) receives the pixel data in rows and each individual pixel element responds accordingly. The pixel elements of the spatial light modulator (16) emit light or reflect light from a source (18) and generate a video frame for display on a screen (20). By exploiting the addressing functions of the spatial light modulator (16), the SLM-based video receiver (10) displays a video frame using a field of pixel data.

Abstract: A controller (800) for a pulse width modulated display system. The controller (800) periodically determining the output of a light source by sampling the output of a light detector (808) an creating a smoothed approximation of the periodic waveform of the light source. A processor (806) in the controller (800) reads a base bit split sequence from a read only memory (804) and modifies the sequence by lengthening or shortening the bit periods described therein in order to compensate for the periodic variations of the light source. The modified bit split sequence is stored in two-port random access memory (802) where it is later accessed by both the processor (806) and a sequencer (304). The sequencer (304) reads the modified bit split sequence from the two-port random access memory (802) to determine when to load each bit of image data into a modulator an-ay.

Abstract: A method and device for producing an accurate approximation of a digital input word translated by a monotonic transfer function. The digital word is translated into a non-monotonic output word comprised of a closest-approximation component and an error component. The error component is zero for regions in which each consecutive input word produces a unique closest-approximation component. In regions in which each consecutive input word produces the same closest-approximation component, the error signal represents the number of consecutive input words which produce the same closest-approximation component, and the position within that run of consecutive input words occupied by the present input word.

Abstract: A method and device for producing an accurate approximation of a digital input word translated by a monotonic transfer function. The digital word is translated into a non-monotonic output word comprised of a closest-approximation component and an error component. The error component is zero for regions in which each consecutive input word produces a unique closest-approximation component. In regions in which each consecutive input word produces the same closest-approximation component the error signal represents the number of consecutive input words which produce the same closest-approximation component, and the position within that run of consecutive input words occupied by the present input word.

Abstract: A method of controlling the display period of video data, and system thereof, that matches the frame period of displayed video data to the speed of a color wheel. The period of the color wheel is measured to determine the display period. An optimum frame sequence pattern is selected, based on the display period, to minimize the artifacts created in the displayed image while maximizing the portion of the frame period used to display the image data. The display period for each segment of the frame sequence pattern is scaled to fit the period of the color wheel, and each bit of the image data is loaded into the spatial light modulator and displayed at the proper time.

Abstract: A motor control system provides a low-cost method of phase-locking a motor to an input timing signal. Timer circuits 502, 506 measure the period of a timing signal and the relative phase between the timing signal and a motor rotor. A frequency command generator circuit 520 outputs a motor speed command based on the period of the timing signal and the relative phase of the timing signal compared to the motor rotor. The motor speed command controls the output of a motor driver circuit which drives the motor rotor speed synchronously with the input timing signal. The rotor speed is gradually altered to adjust the relative phase between the input timing signal and the motor rotor. This results in a small frequency-lock error being used to maintain a predetermined phase relationship between the timing signal and the motor rotor.

Abstract: A spatial light modulator based imaging system (30) with improved peak white performance characteristics. The apparent dynamic range of the spatial light modulator (74) is increased by adding light to pixels neighboring a saturated pixel. An apparent bloom effect is created with the pixels neighboring the saturated pixel appearing brighter, to give sunlight reflecting from the surface of a lake, for instance, more sparkle or highlights. Charts or equations are utilized to determine the degree to which pixel brightness is increased for neighboring pixels. The closer a pixel to a saturated pixel, and the greater the saturation of a particular pixel, the greater increase in brightness for neighboring pixels.

Abstract: A digital sampling and separation unit (12) for a television receiver (10) of a composite video signal, such as an NTSC signal, which has a color subcarrier. The video signal is sampled at a frequency selected in accordance with the invention. This frequency provides samples having a definite and repeating phase relationship with the subcarrier signal. (FIG. 4). As a result, phase reference values can be used to convert the samples into correct color difference values.

Abstract: A television system 106 and display method for receiving and displaying television broadcasts having various formats. The television system resizes (106) the various received image formats for display on a common display device. Images are resized horizontally by altering the rate at which data is sampled by the television (106). Images are resized vertically by using vertical scaling algorithms which alter the number of lines in an image. Format detection may be done automatically by decoding information contained in the vertical interval of the television broadcast signal, or by counting the number of lines in each frame. The input format may be indicated by a viewer.

Abstract: A tracking filter (10,80) which transitions from a type 2 loop to a type 1 loop as the loop error approaches 0 for fast settling and convergence without overshoot or ringing. The filter can either be implemented as an analog circuit (10) in hardware or digitally (80) in software. A first integrator (30) or first accumulator (82) is utilized to increment or decrement a discriminator (22,96) output error value as long as the sign of its output (32) from the previous iteration is the same as a sign of the error signal provided to its input (26) by the error discriminator (22,96). The first integrator output is limited to a range by a limiter (42) between a minimum and maximum value. If the sign of the first integrator output is different from the sign of the input, the contents of the first integrator or accumulator are dumped. The output from the first integrator or first accumulator has binary scaling (44,94) to scale its value before adding it to a second integrator (50) or second accumulator (88).

Abstract: A method and apparatus (10) of aligning color modulation data to color wheel filter segments (13) in a field sequential color spatial light modulator display system. A color wheel (12) having a plurality of colored segments (13) joined at spokes (14) is rotated before a narrow light beam (20). The colored light (22) is observed until light of a mixed color is detected, this light of mixed color corresponding to light of equal portions from the two segments adjacent the spoke. The time between a wheel marker (42) is detected and when the predetermined mixed color is observed is measured. Optical sensors (50) can be utilized to sense a mixed color, such as magenta derived from the combination of a red/blue transition, but also can be done manually by briefly illuminating the wheel to visually ascertain this predetermined color.

Abstract: A method and structure for a display system having multiple spatial light modulators (SLMs) (16), each of which contributes an image of one color that is perceived by the viewer as a combined image. The SLMs (16) have more rows and columns of pixel elements (42) than rows or columns of pixel data to be displayed. A window of "active" pixel elements (42) can be shifted up and down or right and left by selecting which pixel elements (42) are to receive data. The addressing circuit (31, 31a, 35, 35a) of each SLM 16 can be controlled so as to accomplish this shifting.

Abstract: A color image display system (10, 110, 120, 150) having a lamp power supply (78, 134, 152) switching rate being a multiple of, and synchronized to, a video frame rate. An AC component of a lamp driving waveform which may cause variations in intensity of the lamp output is synchronized to the video frame rate. Synchronizing the lamp power supply switching rate to the frame rate stops the beating and rolling of color bands in the video frame that may be produced by a ripple in light intensity. An odd number of switching cycles per two frame periods is chosen to alternate the phase of the ripple pattern frame-to-frame for ripple cancellation through integration. The lamp driving waveform may be amplitude modulated (90) to balance a lamp (14) that has spectral deficiencies. A DMD spatial light modulator (26) is utilized to modulate the colored light and generate a light image on a display (42) in either a sequential, or non-sequential image display system.

Abstract: A motor control unit (15c) for synchronizing a color wheel (15) to an incoming video signal and for re-synchronizing the color wheel after a channel change. The motor control unit (15c) has an error control unit (31), which detects an out-of-phase condition, and derives a color wheel sync signal from the pixel sample clock adjusted by any phase error. A drive unit (33) phase locks this sync signal to an index signal provided by the color wheel. The result is a tightly controlled re-synchronization that minimizes perceived effects.

Abstract: A SLM-based projection display system (10) samples and processes video data for delivery to a spatial light modulator (SLM) (13c), and uses a color wheel (14a) to color the SLM-generated images. A frame memory (13b) provides data to the SLM (13c) and is managed so that, if the phase of the incoming video signal changes, a desired phase relationship between the color wheel position and the data available to the SLM (13c) can be maintained. Also, a motor control unit (15a) uses a horizontal sync signal to generate a drive signal for the color wheel motor (16a), which limits the transient time during phase-changing events, and which provides a means for adjusting the phase of the drive signal.