Optical Device Pupil Position Detection Using Curved Reflector
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Solution Overview
Problem
Current pupil-position detecting devices face challenges in achieving real-time response and reducing size and weight while maintaining detection accuracy, as they often rely on image processing and expand the laser beam diameter due to the curvature of the eyeball, leading to suboptimal detection resolution.
Innovation Solution
The proposed solution involves an off-axis optical system with a VCSEL, a concave mirror, and a PSD, where the laser beam is converged and reflected without expanding, allowing precise detection of the pupil position by canceling out the curvature of the eyeball, and optimizing the diameter of the effective region of the concave mirror to ensure high detection resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image processing is used for pupil position detection, then detection accuracy can be maintained, but device size and weight increase
Solution Approach 1:
The patent replaces complex image processing systems with a simplified optical detection system using a VCSEL, curved reflector, and position-sensitive detector. This substitution maintains detection functionality while significantly reducing device complexity and weight by eliminating the need for heavy image processing hardware.
Solution Approach 2:
The patent changes the detection parameter from analyzing full images to measuring the position of reflected light spots directly. By using a position-sensitive detector to measure spot position rather than processing entire images, the system achieves accurate pupil position detection with minimal hardware, resolving the contradiction between accuracy and device weight.
2Adaptability or versatility
If the laser beam diameter is expanded due to eyeball curvature, then the beam can cover the curved surface, but detection resolution decreases
Solution Approach 1:
The patent uses a curved reflector with a specific radius of curvature that matches the eyeball's curvature. This curved surface reflects the laser beam in a manner that compensates for the eyeball's curvature, keeping the beam diameter small while covering the necessary detection area, thus maintaining high detection resolution.
Solution Approach 2:
The patent employs an off-axis optical configuration where the VCSEL, curved reflector, and position-sensitive detector are arranged asymmetrically relative to the eyeball. This asymmetric arrangement allows the laser beam to follow the curved surface of the eyeball without expanding, maintaining small beam diameter and high detection resolution simultaneously.
3Productivity
If real-time response is achieved through simplified detection, then detection speed improves, but detection accuracy may deteriorate
Solution Approach 1:
The patent replaces slow image processing with direct optical position sensing using a position-sensitive detector. This detector provides real-time positional information of the reflected light spot through direct optical measurement, achieving both high detection speed and maintained accuracy by eliminating processing delays.
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 enables accurate and efficient detection of the pupil position with reduced size and weight, improving real-time response and detection accuracy by minimizing the laser beam diameter on the PSD, thus overcoming the limitations of existing technologies.
Implementation Method 1
a light source section configured to emit light
Implementation Method 2
a converging reflector configured to converge and reflect the light from the light source section
Implementation Method 3
converge and reflect the light from the light source section
Implementation Method 4
a position detector configured to detect a position of the light reflected from the irradiation surface
Data Source
AI summary
An optical device includes a light source section configured to emit light; a converging reflector configured to converge and reflect the light from the light source section to an irradiation surface having a curvature; and a position detector configured to detect a light-receptive position of the light reflected from the irradiation surface.