Light Field Near-Eye Display Brightness Compensation
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Solution Overview
Problem
Light field near-eye displays experience uneven brightness distribution and a limited eye box size due to the overlap and coverage of sub-images, resulting in 'broken images' when the eyeball deviates from the convergence area of light beams.
Innovation Solution
Incorporating an eye tracking module to provide eye movement parameters, which are used to shift and adjust the display image, and calculate a compensation mask with opposite brightness distribution to superimpose on the target image, thereby improving brightness uniformity and expanding the eye box size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If sub-images are overlapped and covered by multiple sub-lenses to form a three-dimensional virtual image, then the spatial three-dimensional effect is improved, but the brightness distribution becomes uneven
Solution Approach 1:
The patent applies local quality by assigning different brightness compensation values to different regions of the display image. The compensation mask is generated with spatially varying transparency values that correspond to the local brightness characteristics of each sub-image region, allowing precise local adjustment without changing the overall device structure.
Solution Approach 2:
The patent changes the brightness parameter of different regions by applying a compensation mask with varying transparency values. This parameter change approach adjusts the perceived brightness distribution through digital processing rather than physical modification of the optical system.
2Area of stationary object
If the eye box size is limited by the convergence area of light beams from sub-lenses, then the optical system remains simple, but the user cannot view the complete image when the eyeball deviates from the eye box
Solution Approach 1:
The patent extends the eye box in the horizontal direction by arranging sub-lenses in both horizontal and vertical directions and adjusting their respective eye boxes. This dimensional approach allows the system to achieve a larger effective viewing area without fundamentally changing the optical convergence mechanism.
Solution Approach 2:
The patent makes each sub-lens serve multiple functions by adjusting the eye box parameters of sub-lenses in different directions. The same sub-lens array structure is used to achieve both vertical and horizontal eye box extension, reducing the need for additional specialized optical components.
3Illumination intensity
If a compensation mask is calculated and superimposed on the target image to compensate for brightness, then the brightness uniformity is improved, but the processing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating the compensation mask based on the simulated image brightness distribution before the actual display. This pre-processing approach allows the system to compensate for brightness non-uniformity in advance, reducing the need for complex real-time adjustment mechanisms.
4Adaptability or versatility
If the display image is shifted according to eye movement parameters, then the eye tracking capability is improved, but the system complexity increases
Solution Approach 1:
The patent implements feedback by using the eye tracking module to detect eye movement parameters and using this information to dynamically adjust the display image position. This closed-loop feedback mechanism allows the system to adapt to user eye movements while maintaining a relatively simple overall architecture through software-based image shifting.
Data Source
AI summary
A method for generating virtual reality images and used in a light field near-eye display includes steps of: shifting a display image according to at least one change vector of a plurality of eye movement parameters, and calculating a compensation mask according to a simulated image and superimposing the compensation mask on a target image to generate a superimposed target image, wherein brightness distributions of the simulated image and the compensation mask are opposite to each other. The light field near-eye display is also provided. In this way, the light field near-eye display for generating virtual reality images and the method thereof can achieve the purpose of improving the uniformity of the image and expanding the eye box size.