HMD Diopter Correction for Non-Telecentric Optical Systems
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Solution Overview
Problem
Head-mounted displays (HMDs) with non-telecentric optical systems face challenges in diopter adjustment, leading to differences in image size and distortion between the left and right sides, causing user fatigue due to unsynchronized magnification corrections.
Innovation Solution
The HMD incorporates separate diopter adjustment and image correction devices for each eye, allowing independent diopter adjustments and image corrections using drive mechanisms and image conversion tables to ensure synchronized image display and minimize distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a non-telecentric optical system is used for HMD miniaturization, then the HMD size is reduced, but image size difference and distortion occur between left and right sides during diopter adjustment
Solution Approach 1:
The patent divides the image correction process into separate left-eye and right-eye correction operations. Each eye's image is corrected independently using separate correction tables, allowing precise control over image size and distortion for each side without affecting the other, thus resolving the image consistency issue while maintaining miniaturization benefits
Solution Approach 2:
The patent dynamically changes image parameters (size, distortion) based on diopter adjustment values. By storing multiple correction tables corresponding to different diopter settings and selecting the appropriate table based on current adjustment state, the system compensates for optical distortions while maintaining compact non-telecentric optics
2Ease of operation
If diopter adjustment is performed in a non-telecentric optical system, then focus adjustment is achieved, but screen distortion and magnification changes occur
Solution Approach 1:
The patent pre-calculates and stores correction data in correction tables for various diopter adjustment positions. Before actual viewing, the appropriate correction table is selected based on the diopter setting, and image correction is applied in advance, preventing distortion from affecting the user experience during operation
Solution Approach 2:
The system establishes a feedback loop where diopter adjustment state is continuously monitored, and image correction parameters are automatically adjusted based on this state. The correction amount is determined by the difference between reference and actual diopter values, creating a closed-loop system that maintains image quality throughout adjustment range
3Device complexity
If the same correction table is used for both left and right sides, then correction process is simplified, but image size difference between eyes persists causing user fatigue
Solution Approach 1:
The patent implements separate correction tables and correction processes for left and right eyes. This segmentation allows each eye's image to be optimized independently, eliminating inter-ocular image size differences that cause fatigue, while the overall system remains manageable through modular architecture
Solution Approach 2:
The patent applies different correction parameters to different sides (left vs. right eye) based on their specific optical characteristics and adjustment states. By tailoring correction quality locally to each side's needs rather than applying uniform correction, the system eliminates fatigue-causing discrepancies while maintaining reasonable overall complexity
Data Source
AI summary
A head-mounted display includes a display device configured to display an image, a diopter adjustment device configured to adjust a diopter, and a correction processing circuit serving as an image correction device configured to correct a display image in accordance with a degree of diopter adjustment. In the adjustments made on a left side and a right side, respectively, after diopter adjustment, the display image is corrected in accordance with the degree of diopter adjustment.