Projector Thermal Compensation for Stable Pixel Illumination
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Solution Overview
Problem
Projectors experience thermal changes due to energy dissipation, affecting the intensity of light incident on pixels and degrading the quality of projected images, particularly in high-brightness projectors used in venues with large screens.
Innovation Solution
A projector system that compensates for thermal changes by using thermal sensors to determine the projector's state and adjust image data accordingly, employing a controller to model lightfield characteristics and adjust illumination based on thermal states, including separate thermal states for different groups of emitters and colors, and optionally adjusting the light source and optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the projector operates at high brightness to illuminate large screens, then the illumination intensity is improved, but thermal changes degrade the quality of projected images
Solution Approach 1:
The controller receives feedback from thermal sensors monitoring the projector's thermal state and dynamically adjusts image data and illumination parameters to compensate for thermal changes, maintaining image quality despite high brightness operation
Solution Approach 2:
The system changes operational parameters (image data, illumination intensity, exposure time) based on detected thermal state, allowing the projector to adapt to thermal changes and maintain reliable image quality at high brightness levels
2Reliability
If thermal compensation is implemented by adjusting image data and illumination parameters, then the quality of projected images is improved, but the device complexity increases
Solution Approach 1:
The projector performs self-diagnosis and self-correction by using onboard thermal sensors to monitor its own thermal state and automatically adjusting its operation through the controller, eliminating the need for external calibration equipment or manual intervention
3Illumination intensity
If the pixel attenuates 95% of illumination light to achieve 5% brightness, then the contrast is improved, but light leakage makes it difficult to achieve dark levels
Solution Approach 1:
The system changes the illumination intensity parameter dynamically based on thermal state and required display level, using lower illumination intensities for dark regions to minimize light leakage while maintaining contrast through precise control of the SLM attenuation
Data Source
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AI summary
An image projector (100) comprising: a spatial light modulator (106), an illumination source (102) arranged to illuminate the spatial light modulator (106), optics (104) disposed between the illumination source (102) and the spatial light modulator (106), and a controller (110) configured to: receive image data to be displayed by the spatial light modulator (106), determine a thermal state of the projector (100), select, from a plurality of different point spread functions, a point spread function of the optics (104) based on the determined thermal state, model an illumination pattern of light incident on the spatial light modulator (106) when illuminated by the illumination source (102) via the optics (104), based on the selected point spread function of the optics, adjust the received image data based on the modelled illumination pattern of light so as to compensate for thermal changes in the illumination source (102) and/or the optics (104) of the image projector (100), and output the thermally adjusted image data to the spatial light modulator (106).