VR Eye Tracking Camera Alignment Through Display Lens
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Solution Overview
Problem
Conventional eye tracking techniques in VR glasses suffer from deteriorated accuracy due to miniaturization, which is exacerbated by the need for a hot mirror that increases the size and obstructs the display screen.
Innovation Solution
The eye tracking apparatus is designed with the display screen and eye tracking camera positioned opposite the display lens, with the eye tracking camera adjacent to the edge of the screen, reducing the included angle between their optical axes to 8.5°-9.5°, allowing the camera to receive light directly through the lens and eliminating the need for an inclined hot mirror, thus minimizing size and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional corneal reflection-based eye tracking is used in miniaturized VR glasses, then eye tracking functionality is achieved, but image recognition accuracy deteriorates
Solution Approach 1:
The patent transitions from the conventional hot mirror configuration (requiring inclined arrangement) to a direct optical axis alignment configuration. By changing the spatial dimension of light path arrangement, the system achieves miniaturization while maintaining eye tracking accuracy through optimized optical geometry between the camera, display lens, and cornea reflection points.
Solution Approach 2:
The patent optimizes specific geometric parameters including the included angle between optical axes (set to 8.5°-9.5°), the position of the eye tracking camera relative to the display screen edge, and the focal length relationships. These parameter optimizations enable miniaturized VR glasses to maintain high image recognition accuracy by controlling the RMS radius of imaged spots.
2Measurement precision
If an inclined hot mirror is used for eye tracking, then eye tracking function is achieved, but the size of the apparatus increases
Solution Approach 1:
The patent removes the hot mirror component from the optical path. By extracting this intermediate element, the system eliminates the need for inclined arrangements and reduces the overall apparatus size while maintaining the eye tracking function through direct optical axis alignment between the camera and display lens.
Solution Approach 2:
The patent merges the eye tracking optical path with the display optical path by aligning their optical axes. The eye tracking camera is positioned adjacent to the display screen edge, allowing both functions to share the same optical components and spatial arrangement, thereby reducing the number of separate optical paths and the overall device size.
3Illumination intensity
If the eye tracking camera is positioned to avoid masking the display screen, then display quality is maintained, but the included angle increases reducing spot resolving accuracy
Solution Approach 1:
The patent applies different spatial positioning strategies to different components: the display screen maintains its central position for optimal display quality, while the eye tracking camera is positioned at the edge adjacent to the display screen. This local differentiation allows the camera to capture corneal reflection points without masking the display while controlling the included angle through precise geometric optimization.
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 enhances spot resolving accuracy, reduces the overall size of the apparatus, and maintains high eye tracking performance while ensuring a compact design.
Implementation Method 1
the eye tracking camera receives light passing through the display lens
Implementation Method 2
Conventional eye tracking techniques mainly employ corneal reflection, i.e., enabling eye tracking by computing movements of pupil center based on corneal reflected spots of the light emitted by multiple LEDs
Data Source
AI summary
The disclosure provides an eye tracking apparatus and a virtual reality apparatus. The eye tracking apparatus includes a display screen, a display lens, and an eye tracking camera, the display screen and the display lens being oppositely disposed, and a displaying surface of the display screen facing the display lens; wherein the eye tracking camera is disposed adjacent to an edge of the display screen, a view-finding side of the eye tracking camera faces the display lens, an included angle between an optical axis of the eye tracking camera and an optical axis of the display lens ranges from 8.5° to 9.5°, and the eye tracking camera receives light passing through the display lens.