Eye-Tracking Optics for Virtual Image Center Alignment
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Solution Overview
Problem
Conventional display devices fail to effectively track and adjust the central portion of an image to follow a user's line-of-sight, limiting the user's ability to maintain a clear view of the image.
Innovation Solution
An image following information detecting device with an integrated image light projecting unit, transmissive reflection member, and line-of-sight detection system using invisible light sources, diffractive optical elements, and light receiving elements to detect and adjust the image display system to align with the user's line-of-sight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transmissive reflection member is used to project image light, then the user can visually recognize the image as a virtual image, but the device cannot obtain information for causing the central portion of the image to follow the user's line-of-sight
Solution Approach 1:
The patent divides the optical system into separate functional components: the transmissive reflection member for image projection and the diffractive optical element for line-of-sight detection. This segmentation allows each component to perform its specific function without interfering with the other, enabling both image visibility and line-of-sight information acquisition simultaneously
Solution Approach 2:
The diffractive optical element serves multiple purposes: it detects the user's line-of-sight by receiving invisible light and also works integrally with the transmissive reflection member for image projection. This multi-functionality resolves the contradiction by adding detection capability without removing the imaging function
2Measurement precision
If the reflective diffraction portion size is increased to capture more light, then more line-of-sight information can be obtained, but it may obstruct the user's view of the image
Solution Approach 1:
The patent applies local quality by using invisible light (such as infrared) for line-of-sight detection instead of visible light. This allows the reflective diffraction portion to be positioned and sized appropriately for detection without obstructing the user's view of the visible image, as the detection light is outside the human visual spectrum
Solution Approach 2:
The patent introduces an intermediary medium (invisible light) for line-of-sight detection. This intermediary allows the system to obtain detection information without using visible light that would compete with or obstruct the image projection, resolving the conflict between detection needs and visual field clarity
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
Enables accurate tracking of the image center to follow the user's line-of-sight, maintaining clear visibility and securing a wide visual field without obstructing the user's view.
Implementation Method 1
a diffractive optical element provided integrally with the transmissive reflection member and including a reflective diffraction portion that reflects and diffracts invisible light from the invisible light source toward the eyeball
Implementation Method 2
a diffractive optical element provided integrally with the transmissive reflection member and including a reflective diffraction portion that reflects and diffracts invisible light from the invisible light source toward the eyeball
Implementation Method 3
a transmissive reflection member that reflects a part of the image light projected from the image light projecting unit toward an eyeball
Data Source
AI summary
An image following information detecting device capable of obtaining information for causing a central portion of an image to follow a line-of-sight of a user. The device includes: an image display system including an image light projecting unit, and a transmissive reflection member that reflects a part of the image light toward an eyeball and transmits other parts; and a line-of-sight detection system including at least one invisible light source, a diffractive optical element provided integrally with the transmissive reflection member and including a reflective diffraction portion that reflects and diffracts invisible light toward the eyeball, and a light receiving element that receives the invisible light reflected by the eyeball. A portion irradiated with a central portion of the image light of the transmissive reflection member and the reflective diffraction portion overlap each other when viewed from a thickness direction of the transmissive reflection member.