Eye-Tracking Device Using Light Guide Plate for Compact VR
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Solution Overview
Problem
Current eye-tracking devices for VR, AR, and MR applications face challenges in accurately and rapidly tracking the angle of rotation of an observer's eye, often requiring complex calculations and high-power light sources, which can lead to bulky and power-intensive systems.
Innovation Solution
An eye-tracking device comprising a light source, a light guide plate, a photodetector array, and a signal processor that uses infrared light and a beam splitter to determine the angle of rotation based on a 2D intensity distribution, with a compact and efficient design that includes holographic optical elements and a varifocal lens for improved focus and tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex calculations and high-power light sources are used in eye-tracking devices, then measurement precision and tracking accuracy are improved, but device complexity and power consumption increase
Solution Approach 1:
The patent replaces complex computational algorithms with a simplified optical detection system. The eye-tracking device uses a light guide plate with specific optical properties and a photodetector array that directly measures eye position through light reflection patterns, eliminating the need for complex image processing and calculations while maintaining high tracking accuracy
Solution Approach 2:
The patent changes the operational parameters by using low-power infrared light sources instead of high-power visible light sources. The system operates in the infrared spectrum with reduced power consumption, achieving accurate eye tracking through optimized optical path design and photodetector sensitivity rather than increasing light source power
2Measurement precision
If high-power light sources are used in eye-tracking devices, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The patent substitutes high-power light sources with low-power infrared LEDs combined with an optimized optical system. The light guide plate enhances light distribution efficiency, and the photodetector array is optimized for infrared detection, allowing accurate eye tracking with minimal power consumption from the light source
Solution Approach 2:
The patent changes the wavelength parameter to infrared spectrum and reduces the power parameter of the light source. By operating in the infrared range with low-power LEDs and using optical enhancement techniques, the system achieves high measurement precision while consuming minimal energy
3Measurement precision
If complex optical systems are used in eye-tracking devices, then measurement precision is improved, but device complexity and size increase
Solution Approach 1:
The patent replaces complex mechanical optical components with a planar light guide plate-based optical system. The light guide plate integrates light distribution, guidance, and detection functions in a single flat component, eliminating the need for multiple lenses, mirrors, and adjustment mechanisms while maintaining high tracking accuracy
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
The solution enables accurate and rapid tracking of the observer's eye angle over a wide range, reducing power consumption and system size while maintaining high accuracy, making it suitable for compact and lightweight applications in VR, AR, and MR systems.
Implementation Method 1
a light guide plate configured to transmit the illumination light emitted from the light source to an observer's eye and transmit the illumination light reflected from the observer's eye
Implementation Method 2
a beam splitter configured to transmit the illumination light emitted from the light source to the first input/output coupler and transmit the illumination light incident from the first input/output coupler to the photodetector array
Implementation Method 3
a photodetector array configured to detect the illumination light reflected from the observer's eye
Data Source
AI summary
Provided are an eye-tracking device that may rapidly and accurately track an observer's eye and may be made compact, and a display apparatus including the eye-tracking device. The eye-tracking device includes: a light source configured to emit an illumination light; a light guide plate configured to transmit the illumination light emitted from the light source to an observer's eye and transmit the illumination light reflected from the observer's eye in a direction opposite to a propagation direction of the illumination light emitted from the light source; a photodetector array configured to detect the illumination light reflected from the observer's eye; and a signal processor configured to determine an angle of rotation of the observer's eye based on a two-dimensional (2D) intensity distribution of the illumination light detected by the photodetector array.