Microsoft Technology Licensing, LLC

Wenjun Liao

Chuan Pu

Algird Michael Gudaitis

Ruipeng Sun

Seyed Ahmad Mortazavi

Implementations of local demura algorithms for correcting display artifacts are provided. One aspect includes a method comprising: receiving image data; segmenting the image data into a plurality of regions of interest; applying a plurality of demura algorithms to the plurality of regions of interest to generate a plurality of corrected regions of interest by at least: applying a first demura algorithm to a first region of interest; and applying a second demura algorithm different from the first demura algorithm to a second region of interest; and generating a corrected image using at least the plurality of corrected regions of interest.

Local demura algorithms for correcting display artifacts

One example provides a method enacted on a scanning display device comprising an illumination source, and a scanning mirror system including a sense circuit coupled to a scanning mirror. The method comprises operating the scanning mirror system using a drive signal while operating the illumination source to thereby project an image, obtaining a control parameter based at least upon an output of the sense circuit, and comparing the control parameter to a noise threshold condition. The method further comprises, when the control parameter does not meet the noise threshold condition, continuing operating the scanning mirror according to the drive signal. The method also comprises, when the control parameter meets the noise threshold condition, adjusting the drive signal to form an adjusted drive signal to change a trajectory of the scanning mirror.

Utilizing noise threshold conditions for controlling scanning mirrors

A laser beam scanning ('LBS') display device is configured with an optical system that includes a laser beam emitter configured to emit a laser beam. The optical system also includes a driver configured to generate a driving signal for controlling a mirror, such as a microelectromechanical systems (“MEMS”) mirror. The optical system also includes a controller configured to generate a driving signal while rejecting a system disturbance response.

Disturbance rejection for laser beam scanning display

This disclosure provides methods and systems that adaptively adjust the gain of the drive signal to a slow-scan mirror to compensate and stabilize the mirror to achieve desired performance metrics. Non-ideal characteristics of the slow-scan mirror, including the mirror and related assembly, exhibit behaviors that impact the overall gain of the device, which changes over time and operating environment. To compensate for these non-ideal characteristics, the drive signal to the slow-scan mirror may need to be adjusted to achieve the desired beam deflection angle. An adaptive inner loop gain control structure may be employed to dynamically adjust the gain of the inner-control loop to achieve a target gain such that the overall gain variations from the slow scan mirror and other components are scan mirror such that compensated and stabilized. The parameters, logic and blocks of the inner loop gain control may be implemented in hardware, software, or combinations thereof.

Adaptive inner loop gain control for laser beam scanning displays

Techniques are described herein that are capable of adjusting a center frequency of an adaptive voltage controlled oscillator (VCO) that is included in an adaptive phase lock loop (PLL) and/or a phase difference target of the adaptive PLL. An adaptive PLL is a PLL that includes an adaptive VCO. An adaptive VCO is a VCO that is capable of adjusting its center frequency and/or a phase difference target of the adaptive PLL that includes the adaptive VCO. The adaptive PLL may be configured to drive (e.g., control) a device. A drive signal that is used to drive the device and a resulting output signal that is proportional to movement of the device may be fed back to respective inputs of the adaptive PLL so that the phases of those signals may be processed to facilitate adjustment of the center frequency and/or the phase difference target.

Adaptive phase lock loop that adjusts its phase difference target

A laser beam scanning ('LBS') display device is configured with an optical system that includes a laser beam emitter configured to emit a laser beam. The optical system also includes a driver configured to generate a driving signal for controlling a mirror, such as a microelectromechanical systems ('MEMS') mirror. The optical system also includes a controller configured to generate a driving signal while rejecting a system disturbance response.

A laser beam display device that can dynamically control the resonant frequency of a mirror is provided. The increase the reliability of a device by controlling the resonant frequency of a mirror instead of requiring components of a display device to react to changes in the resonant frequency of a mirror. A controller can drive a mirror with an input signal, receive a signal or data indicating a target resonant frequency, and bias the input signal to control the resonant frequency of the mirror. In some embodiments, the controller can also receive a feedback signal from a mirror indicating a current resonant frequency. The controller can also bias the input signal to increase or decrease the current resonant frequency. By dynamically controlling the resonant frequency of a mirror, a device can minimize any difference between the current resonant frequency detected in a feedback signal and the target resonant frequency.

Control loop for stabilizing a resonant frequency of a mirror of a laser beam scanning display

The techniques disclosed herein provide apparatus, methods and systems that adaptively adjust the signal waveform (or waveshape) of the drive signal to a slow-scan mirror to compensate for non-linearities observed in the slow-scan feedback signal from a slow-scan mirror. Over large scan angles and high temperatures, the slow-scan mirror in a laser beam scanning device may exhibit a nonlinear response to the drive signal that results in poor image quality issues such as bright lines, bands in the display image, and image distortion. The presently disclosed technologies track the linearity performance of the overall system by detecting non-linearities in waveform of the slow-scan feedback signal real time, and consequently apply a pre-distortion to the drive waveform to compensate for these detected non-linearities. The parameters, logic and blocks of the control may be implemented in hardware, software or combinations thereof.

Adaptive waveform non-linearity compensation for laser beam scanning displays

A display device, including a display surface, a laser beam emitter, and a processor. The display device may further include a slow-scan MEMS driver configured to drive a slow-scan mirror and a fast-scan MEMS driver configured to drive a fast-scan mirror. The slow-scan mirror and the fast-scan mirror may reflect the laser beam onto an active region of the display surface. The slow-scan period may include a scanning interval in which the slow-scan mirror is configured to move to a final scanning position at one or more scanning ramp rates and a flyback interval in which the slow-scan mirror is configured to return to the initial scanning position. The processor may generate a modified slow-scan drive signal by modifying one or more of the initial scanning position, the final scanning position, and the scanning ramp rate in a blank region of the display surface.

Modified slow-scan drive signal

Adaptive phase lock loop that adjusts center frequency of voltage controlled oscillator therein

The techniques disclosed herein provide methods, devices, and systems to compensate the drive waveform to a slow-scan mirror in a laser beam scanning (LBS) display device. The slow-scan controller generates the drive waveform, which is combined with feedback and coupled to the input of a notch filter in the control loop. Ripple in the slow-scan mirror trajectory, which occurs as a consequence of mismatches between the notch frequency of the notch filter and the resonance of the slow-scan mirror, is effectively suppressed in real time by an adaptive notch compensator. Consequently, the described compensation scheme allows for relaxed notch filter design criteria with high tolerance and mitigation of ripple is achieved at reduced cost. The parameters, logic and blocks of the adaptive notch compensator scheme may be time-domain or frequency domain solutions that are implemented, in hardware, software or combinations thereof.

Closed loop controller for laser beam scanning display with high tolerance to mirror resonance frequency variation

Techniques are described herein that are capable of adjusting a notch frequency of an adaptive notch filter ('filter') to track a resonant frequency of a slow scan MEMS mirror ('mirror'). For instance, an adaptive feedback may be configured to determine one or more resonant frequencies of the mirror based at least in part on a frequency response of an output signal that is proportional to movement of the mirror. The adaptive feedback may be further configured to adjust at least one notch frequency of the filter to track at least one respective resonant frequency of the mirror. The filter may be configured to modify a magnitude of a frequency response of a combination of the filter and the mirror to be substantially constant by suppressing the at least one notch frequency in a frequency response of the mirror.

Adjusting notch frequency of adaptive notch filter to track resonant frequency of slow scan microelectromechanical systems (MEMS) mirror

A resonance system is disclosed, which includes a first resonance device configured to receive a drive signal and generate an output signal, a second resonance device configured to receive a control signal and generate the drive signal based on the received control signal, and a controller configured to generate the control signal based on the output signal such that a phase difference between the control signal applied to the second resonance device and the output signal of the first resonance device corresponds to a predetermined phase shift value.

Phase control device and method for multi-resonance system

The techniques disclosed herein provide methods and systems that adaptively adjust control system update rates to optimize power consumption for laser beam scanning display devices. A display device can adjust an update rate based on changes within the system and/or changes of a surrounding environment, e.g., vibration level, a humidity level, a temperature, a resonant frequency, and/or an age of a device. As variations of the environmental properties change, the device can increase or decrease the control system update rates. Additionally, or alternatively, the system can perform a resonance calibration process to determine a resonant frequency. Based on a change in a determined resonant frequency, the system may increase or decrease the control system update rates. By dynamically controlling the system update rates based on environmental and/or physical properties of a device, the device can optimize power consumption while maintaining a desirable image quality.

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Mountain View, CA, United States of America

Wenjun Liao