HMD Optical System Eye Tracking Alignment
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Solution Overview
Problem
Existing head-mounted displays (HMDs) face challenges in accurately detecting and correcting the positional gap between the optical system and the observer's eye, leading to issues like color shift, decreased contrast, and image distortion due to misalignment.
Innovation Solution
An image display apparatus equipped with a positional relationship detecting unit to estimate the eyeball position using methods like sclera reflection or electro-oculogram, and a correcting unit that adjusts the optical system's position based on detected gaps, allowing for precise alignment and correction of the optical system relative to the observer's eye.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual movement adjustment of the optical system is implemented, then the positional gap between the eye and optical system can be corrected, but the observer cannot know the amount of positional gap making optimal adjustment difficult
Solution Approach 1:
The patent implements a feedback mechanism where the detection unit measures the positional gap between the eye and optical system, and this measurement information is fed back to the control unit which then adjusts the optical system position accordingly. This closed-loop feedback enables automatic correction of the positional gap without requiring the observer to manually estimate or guess the adjustment amount, thereby resolving the contradiction between measurement precision and ease of operation.
2Device complexity
If the optical system position is fixed, then the device structure is simple, but image quality deteriorates due to color shift, decreased contrast, and image distortion when a gap exists between the optical system center and eye position
Solution Approach 1:
The patent transforms the fixed optical system into a dynamic, adjustable system. The detection unit continuously monitors the positional relationship between the eye and optical system, and the control unit dynamically adjusts the optical system position to maintain optimal alignment. This dynamic adjustment capability ensures image quality stability (preventing color shift, contrast decrease, and distortion) while adding necessary complexity to the device structure.
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 enables accurate correction of the positional gap between the optical system and the observer's eye, improving image quality by preventing color shift and distortion, and allowing for optimal observation of magnified virtual images.
Implementation Method 1
an eyeball position estimating unit to estimate an eyeball position of the eye of the observer may be further included and the positional relationship detecting unit may detect a positional relationship between the optical system and the eye of the observer based on the eyeball position estimated by the eyeball position estimating unit. The estimation of the eyeball position may be performed, for example, by application of a sclera reflection method
Implementation Method 2
The estimation of the eyeball position may be performed, for example, by application of a sclera reflection method, an electro-oculogram (EOG) method
Data Source
AI summary
It is made possible to correct a positional gap between an optical system and an eye of an observer appropriately.Based on an eyeball position of the eye of the observer, a positional relationship between the optical system, which leads an image displayed on a display element to the eye of the observer, and the eye of the observer, that is, a positional gap therebetween is detected. Based on the positional relationship detected in such a manner, the positional relationship between the optical system and the eye of the observer is corrected. For example, the positional gap is electronically corrected by performing shift control of a position of the image displayed on the display element. Also, for example, the positional gap is mechanically corrected by performing shift control of the optical system including the display element.