Eye Movement Tracking Optical Structure for VR Lens Distortion
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Solution Overview
Problem
The issue of optical distortion in VR lens groups leads to errors in eye movement tracking due to the limited number of lenses, affecting the accuracy of signal magnitude received by sensors in VR systems.
Innovation Solution
An eye movement tracking device with a light source, photoelectric sensing elements, and an optical structure that includes optical transparent areas corresponding to the sensing elements, allowing light rays to pass through the center of the optical lens, reducing or eliminating distortion and improving tracking accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a VR lens group is used to improve overall aesthetics and reduce product thickness, then the quantity of lenses is limited, but lens distortion occurs causing error in signal magnitude received by sensor
Solution Approach 1:
A light guide plate is introduced as an intermediary component between the lens and sensor. The light guide plate receives scattered light from the lens and guides it to the sensor through total internal reflection, converting the distorted light paths into accurate positional information for eye tracking without requiring additional lenses
Solution Approach 2:
The patent replaces the traditional optical lens-based eye tracking mechanism with a light guide plate-based system. Instead of using multiple lenses to control light paths, the system uses a planar light guide plate with specific refractive indices and total internal reflection to achieve the same eye tracking function with improved accuracy
2Length of stationary object
If the quantity of lenses is limited to reduce product thickness, then aesthetics and compactness are improved, but optical distortion causes tracking errors
Solution Approach 1:
The light guide plate serves as a mediator that decouples the thickness reduction benefit from the tracking accuracy problem. It allows the system to maintain thin form factor while achieving accurate eye tracking through its light guiding properties rather than relying on complex lens assemblies
Solution Approach 2:
The patent changes the optical parameters by using a light guide plate with specific refractive index (1.4-1.7) and controlling the incident light angles to achieve total internal reflection. This parameter optimization allows accurate light guidance without the need for multiple lenses, maintaining thinness while improving reliability
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 configuration ensures collimated light rays are received by the sensing elements, enhancing the accuracy of eye movement tracking by minimizing lens-induced distortion.
Implementation Method 1
an optical structure, located between the optical lens and the display module, the optical structure comprising a plurality of optical transparent areas which is in one-to-one correspondence to the plurality of photoelectric sensing elements, each of the plurality of optical transparent areas being configured for transmitting the second light ray to a corresponding photoelectric sensing element
Implementation Method 2
a plurality of photoelectric sensing elements, arranged in a non-display region of the display module, the plurality of photoelectric sensing elements being configured for receiving a second light ray to determine a position of a pupil of the eye
Implementation Method 3
a VR lens group is disposed between an eye and a display screen. A diffuse light reflected back by the eyeball will be refracted after passing through the lens group
Data Source
AI summary
An eye movement tracking device includes: a light source located at the light-emitting side of the display module and configured for providing a first light ray for irradiating an eye; a plurality of photoelectric sensing elements arranged in a non-display region of the display module and configured for receiving a second light ray to determine a position of a pupil of the eye; an optical structure located between the optical lens and the display module, including a plurality of optical transparent areas in one-to-one correspondence to the plurality of photoelectric sensing elements, each of the optical transparent areas being configured for transmitting the second light ray to a corresponding photoelectric sensing element; the second light ray being a light ray which passes through a center point of the optical lens after the first light ray is reflected back by the eye. An eye movement tracking method is also disclosed.