Abstract: A system and method of stabilizing laser output levels includes a laser (10), an injection circuit for injecting a radio frequency waveform, and a control circuit for energizing and stabilizing the laser. The radio frequency waveform injected by the injection circuit has a high duty cycle to maintain high output power while providing a stable multimode spectrum. A back facet photodiode sensor (102) detects radiation emitted from a back facet semiconductor laser (101) and provides a feedback signal to the control circuit (41) for maintaining the laser output power. The response of the photodiode is not fast enough to track intensity variations due to the RF waveform, and thus provides feedback to the control circuit (41) only when there is a substantial need to adjust laser power.

Abstract: The need is met according to the present invention by providing a method of correcting pixel by pixel variations in a display, the method including the steps of creating a defect map of pixel intensity offsets for the display; correcting an input signal according to the defect map; and displaying the corrected input signal on the display, wherein the offset defect map is created by modulating a pixel in the display at a predetermined rate at a predetermined intensity; sensing the display with a photosensor to generate a sensed signal; demodulating the signal with a synchronous demodulator at the predetermined rate to produce a demodulated signal representing a sensed intensity; and employing the sensed intensity and the predetermined intensity to generate a correction offset.

Abstract: A closed loop three color alignment system for a digital projector comprises a light source and an optical engine (50) which splits a beam of light from the light source into first, second, and third wavelength bands. A first, second, and third spatial light modulator (11, 12, 16) imparts image data and a first, second, and third fiducial data to the first, second, and third wavelength bands. A combiner combines the modulated first, second, and third wavelength bands. A diverter diverts a portion of the combined modulated wavelength bands to a sensor. The sensor (21) senses a relative position of each of the fiducials and sends the position information to a microprocessor. The microprocessor then determines an error based on the relative position of the fiducials. The microprocessor then sends a signal to at least one component of the system to resolve the error.

Abstract: An apparatus and method for calibration of each individual driver channel in a multichannel driver circuit for a spatial light modulator used in an image display apparatus. A separate calibration sequence is initiated in which, for each positive and negative half-cycle of the driver circuit, a ramped voltage, applied as the drive circuit voltage (18), is compared against a standard black-video drive voltage. When the ramped voltage equals the standard drive voltage, calibration for this half-cycle is complete and a digital value corresponding to a correction component of the ramped voltage is stored in memory (40). The process is duplicated for each positive and negative half-cycle of the drive voltage signal (18). For gain calibration, a ramped voltage is applied as the drive circuit voltage 18 and compared against a standard white-video signal level.

Abstract: A method and projection system (10) for increasing the color gamut of images projected onto a display surface (140) by using four or more light sources (12), where the light sources (12) are selected for high brightness and narrow wavelength characteristics and are selected from optimal wavelengths for color gamut expansion. Light sources (12) for large-scale projection environments are preferably lasers. Smaller systems may employ LEDs or other relatively saturated, relatively bright light sources (12).

Abstract: A method and projection system (10) for increasing the color gamut of images projected onto a display surface (140) by using four or more light sources (12), where the light sources (12) are selected for high brightness and narrow wavelength characteristics and are selected from optimal wavelengths for color gamut expansion. Light sources (12) for large-scale projection environments are preferably lasers. Smaller systems may employ LEDs or other relatively saturated, relatively bright light sources (12).

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A system and method of stabilizing laser output levels includes a laser (10), an injection circuit for injecting a radio frequency waveform, and a control circuit for energizing and stabilizing the laser. The radio frequency waveform injected by the injection circuit has a high duty cycle to maintain high output power while providing a stable multimode spectrum. A back facet photodiode sensor (102) detects radiation emitted from a back facet semiconductor laser (101) and provides a feedback signal to the control circuit (41) for maintaining the laser output power. The response of the photodiode is not fast enough to track intensity variations due to the RF waveform, and thus provides feedback to the control circuit (41) only when there is a substantial need to adjust laser power.

Abstract: A closed loop three color alignment system for a digital projector comprises a light source and an optical engine (50) which splits a beam of light from the light source into first, second, and third wavelength bands. A first, second, and third spatial light modulator (11, 12, 16) imparts image data and a first, second, and third fiducial data to the first, second, and third wavelength bands. A combiner combines the modulated first, second, and third wavelength bands. A diverter diverts a portion of the combined modulated wavelength bands to a sensor. The sensor (21) senses a relative position of each of the fiducials and sends the position information to a microprocessor. The microprocessor then determines an error based on the relative position of the fiducials. The microprocessor then sends a signal to at least one component of the system to resolve the error.

Abstract: The need is met according to the present invention by providing a method of correcting pixel by pixel variations in a display, the method including the steps of creating a defect map of pixel intensity offsets for the display; correcting an input signal according to the defect map; and displaying the corrected input signal on the display, wherein the offset defect map is created by modulating a pixel in the display at a predetermined rate at a predetermined intensity; sensing the display with a photosensor to generate a sensed signal; demodulating the signal with a synchronous demodulator at the predetermined rate to produce a demodulated signal representing a sensed intensity; and employing the sensed intensity and the predetermined intensity to generate a correction offset.

Abstract: An apparatus and method for calibration of each individual driver channel in a multichannel driver circuit for a spatial light modulator used in an image display apparatus. A separate calibration sequence is initiated in which, for each positive and negative half-cycle of the driver circuit, a ramped voltage, applied as the drive circuit voltage (18), is compared against a standard black-video drive voltage. When the ramped voltage equals the standard drive voltage, calibration for this half-cycle is complete and a digital value corresponding to a correction component of the ramped voltage is stored in memory (40). The process is duplicated for each positive and negative half-cycle of the drive voltage signal (18). For gain calibration, a ramped voltage is applied as the drive circuit voltage 18 and compared against a standard white-video signal level.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A system and method of stabilizing laser output levels includes a laser (10), an injection circuit for injecting a radio frequency waveform, and a control circuit for energizing and stabilizing the laser. The radio frequency waveform injected by the injection circuit has a high duty cycle to maintain high output power while providing a stable multimode spectrum. A back facet photodiode sensor (102) detects radiation emitted from a back facet semiconductor laser (101) and provides a feedback signal to the control circuit (41) for maintaining the laser output power. The response of the photodiode is not fast enough to track intensity variations due to the RF waveform, and thus provides feedback to the control circuit (41) only when there is a substantial need to adjust laser power.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A stabilized laser is comprised of a laser for generating radiation responsive to a control signal. A control circuit connected to the laser provides the control signal and an injection circuit injects a radio frequency into the control circuit and the control signal. A back facet photodiode sensor detects radiation emitted from a back faceted laser diode and provides a feedback signal to the control circuit for adjusting laser output power.

Abstract: A stabilized frequency oscillating circuit outputs a pixel clock signal to an image scanner for controlling pixel rate at various writing positions along a scan line. The circuit includes a synchronization circuit having a first control signal component output to adjust a nominal output frequency of the oscillator; and a frequency profiling circuit having a second control signal component output which varies as a function of writing position along the scan line to determine a corrected output frequency of the oscillator which varies as a function of writing position along the scan line.

Abstract: A laser diode controller (30) having a constant current source (60) which supplies current to a laser diode (90) is disclosed. A current shunt switch (40) directs current to either the laser diode (90) or to a bypass circuit (42). A thermal compensator (70) alters a current level of the constant current source (60) as a function of on-time of the laser diode (90) to compensate for changes in optical power conversion efficiency due to temperature changes in the laser diode. A thermo electric cooler controller (80) maintains a constant temperature of a substrate on which the laser diode is mounted. In one embodiment, an array of sample and hold amplifiers (50) eliminates a need for multiple DACs.