Retinal Projection Device Single Light Source Beam Positioning
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Solution Overview
Problem
Existing image projection devices that project images onto the retina require separate light sources for image and checking light beams, leading to increased device size.
Innovation Solution
An image projection device with a single light source emitting both image and checking light beams, where the optical system projects these beams onto the eye in a specific positional relation, and a light detector controls the light source or optical system based on reflected light detection, allowing for concurrent projection and adjustment of beam positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate light sources are used for image light beam and checking light beam, then the light detection and control function is achieved, but the device size increases
Solution Approach 1:
The patent combines the image light source and checking light source into a single light source unit. This light source emits both the image light beam (visible light for displaying images) and the checking light beam (infrared light for eye tracking and authentication), thereby reducing the number of components and minimizing device size while maintaining all necessary functions.
Solution Approach 2:
The single light source is designed to perform multiple functions: it emits visible light for image projection onto the retina and simultaneously emits infrared light for eye position detection, authentication, and checking. This multi-functional design eliminates the need for separate light sources and reduces overall device complexity.
2Volume of moving object
If one light source emits both image light beam and checking light beam, then the device size is reduced, but the light projection control complexity increases
Solution Approach 1:
The optical system is segmented into distinct functional units: the light source unit emits both beams, the optical system projects the image light beam onto the retina through the pupil, and a separate checking unit detects the infrared checking light beam reflected from the eye. This segmentation allows independent control and detection pathways, simplifying the overall control architecture despite the multi-functional light source.
Solution Approach 2:
The optical system acts as an intermediary that separates the pathways of the image light beam and checking light beam. It projects the image light beam onto the retina while allowing the checking light beam to be reflected from the eye surface (iris/cornea) to the light detector, enabling simultaneous operation without interference.
3Measurement precision
If the checking light beam is projected onto the iris while the image light beam passes through the pupil, then the beam positioning precision is improved, but the optical system complexity increases
Solution Approach 1:
The optical system is designed with local quality variations: it directs the image light beam (visible light) through the pupil to the retina for high-resolution image projection, while simultaneously directing the checking light beam (infrared light) to illuminate the iris surface for reflection-based detection. This localized optimization of light paths achieves precise beam positioning for different functions using a unified optical system.
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 configuration reduces the size of the image projection device while maintaining control over the light source or optical system during image projection, ensuring effective beam positioning and detection.
Implementation Method 1
an optical system that projects the image light beam emitted from the one light source onto a first surface region of an eye of a user
Implementation Method 2
projects the image light beam emitted from the one light source onto a first surface region of an eye of a user to project the image light beam onto a retina of the user
Implementation Method 3
projects the checking light beam emitted from the one light source onto a second surface region of the eye of the user
Implementation Method 4
a light detector that detects a reflected light that is the checking light beam reflected by the eye of the user
Data Source
AI summary
An image projection device includes: one light source unit emitting an image light beam, which forms an image, of visible light and a checking light beam of visible light; an optical system projecting the image light beam emitted from emitted from the one light source unit onto a first surface region of an eye of a user to project the image light beam onto a retina of the user, and projecting the checking light beam emitted from the one light source unit onto a second surface region, which is distant from the first surface region, of the eye of the user; a light detector detecting a reflected light that is the checking light beam reflected by the eye of the user; and a controller controlling at least one of the one light source unit and the optical stem based on a detection result of the reflected light by the light detector.