Display Finder Optics: Angled Eye Imaging for Reliable Gaze Detection
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Solution Overview
Problem
Existing camera configurations with a line-of-sight input function face challenges in capturing the user's eye without increasing apparatus size or cost when the optical axes of the eyeball-imaging and finder optical systems are made independent, leading to difficulties in maintaining the eye within the imaging range as the user's eye moves.
Innovation Solution
The optical axes of the eyeball-imaging and finder optical systems are arranged non-parallel and intersect at a small angle, eliminating the need for a light-splitting prism, allowing for improved optical performance without size or cost increases, and the line-of-sight detection system is positioned to minimize vignetting by the eyelid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the optical axis of the eyeball-imaging optical system and the optical axis of the finder optical system are made independent from each other to remove the light-splitting prism, then the apparatus size and cost are reduced, but it becomes more difficult to capture the user's eye with the eyeball image sensor
Solution Approach 1:
The patent positions the eyeball image sensor and imaging optical system at an angle (non-parallel optical axes) relative to the finder optical system, transitioning from a collinear arrangement to a spatially separated angular arrangement. This dimensional change allows the eye imaging function to operate independently without requiring a light-splitting prism, thereby reducing apparatus size and cost while maintaining reliable eye capture through optimized angular positioning
2Adaptability or versatility
If the user's eye moves away from the eye lens, then the pupil center position in the captured eye image changes, but the eye easily moves out of the imaging range of the eyeball image sensor
Solution Approach 1:
The patent changes the angular parameter between the optical axes of the eyeball-imaging system and the finder system from parallel (0 degrees) to a specific non-parallel angle. This parameter change optimizes the imaging geometry to maintain the user's eye within the imaging range even when the eye moves away from the lens, thereby expanding the effective imaging range while adapting to variations in eye position
Data Source
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AI summary
A display apparatus according to the present invention, includes: a display panel; a display optical system for looking at the display panel; an image sensor for capturing an eye of an user looking at the display panel, the image sensor having a rectangular imaging plane; and an imaging optical system for forming an optical image of the eye on the imaging plane, wherein the imaging optical system has an optical axis that is nonparallel to an optical axis of the display optical system, and a projected line of the optical axis of the display optical system on the imaging plane is substantially parallel to a long side of the imaging plane.