HMD Luminance Control for Yellowing Optical Member Compensation
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Solution Overview
Problem
Head-mounted displays (HMDs) face challenges in maintaining white balance and extending the lifespan of light-emitting elements due to the yellowing of optical components over time, which affects image quality and light emission intensity.
Innovation Solution
Incorporating a yellowing optical member that adjusts luminance based on estimated yellowing degree, using different opening ratios for red, green, and blue light depending on wavelength bands, and employing a yellowing degree estimation unit and luminance adjustment unit to maintain image balance and extend the lifespan of light-emitting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light emission intensity is increased by increasing injection current to adjust white balance, then white balance adjustment is improved, but lifespan of light-emitting element shortens
Solution Approach 1:
The patent applies preliminary action by adjusting the opening ratios of red, green, and blue light-emitting elements in advance to account for the yellowing of optical components over time. Instead of increasing injection current to compensate for yellowing, the system pre-configures different opening ratios that anticipate the optical changes, thereby maintaining white balance without accelerating light-emitting element degradation.
Solution Approach 2:
The patent changes the parameter of opening ratio for each wavelength band (red, green, blue) to compensate for yellowing effects. By adjusting these opening ratios based on predicted yellowing degrees, the system maintains accurate color reproduction without needing to increase light emission intensity through higher currents, thus preserving light-emitting element lifespan.
2Illumination intensity
If opening ratios are adjusted to compensate for yellowing, then white balance is maintained, but device complexity increases
Solution Approach 1:
The patent implements self-service by incorporating a yellowing degree estimation unit that automatically estimates the yellowing of optical components and triggers appropriate luminance adjustments. The system monitors and compensates for its own degradation without external intervention, maintaining white balance through automated opening ratio adjustments based on estimated yellowing degrees.
Solution Approach 2:
The patent applies feedback by using the yellowing degree estimation unit to continuously assess the state of optical components and adjusting the opening ratios of light-emitting elements accordingly. This closed-loop feedback mechanism ensures white balance is maintained by dynamically responding to detected yellowing without requiring manual calibration or complex external control systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively maintains white balance and extends the lifespan of light-emitting elements by adjusting luminance according to the yellowing of optical components, ensuring consistent image quality over time.
Implementation Method 1
a yellowing optical member that is disposed on an optical path of imaging light emitted from the display element, and turns yellow with age
Data Source
AI summary
A panel unit configured to, for imaging light, use different opening ratios depending on a wavelength band for displaying an image, a yellowing optical member that is disposed on an optical path of imaging light emitted from the panel unit, and turns yellow with age, a yellowing degree estimation unit configured to estimate, by prediction, a yellowing degree of the yellowing optical member with age, and a luminance adjustment unit configured to, depending on yellowing of the yellowing optical member, based on data of the yellowing degree estimation unit, adjust luminance of an image in the panel unit, are provided.