Folded-Path Lens Module Layout for VR Eye Tracking
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Solution Overview
Problem
Existing VR glasses with folded optical paths face challenges in integrating an eye tracking function due to limited space within the lens barrel, as conventional solutions require a hot mirror that occupies internal space and affects imaging quality.
Innovation Solution
A lens module design that includes a light emitting unit, lens barrel, and eye camera, where the eye camera is inclined and positioned outside the lens barrel, allowing infrared light reflection and tracking without occupying internal space, and incorporating a mirror reflector to adjust the optical path for eye tracking while minimizing impact on imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a hot mirror is disposed inside the lens barrel to implement eye tracking, then the eye tracking function is achieved, but the lens barrel thickness increases and internal space is occupied
Solution Approach 1:
The eye camera is moved from the internal space of the lens barrel to an external position on the lens barrel surface. The optical axis of the eye camera is inclined relative to the axial direction of the lens barrel, allowing the camera to extend into the inner cavity of the lens barrel without occupying internal space. This dimensional repositioning enables eye tracking functionality while maintaining a thin lens barrel profile suitable for folded optical path VR glasses.
2Adaptability or versatility
If a hot mirror is disposed inside the lens barrel to implement eye tracking, then the eye tracking function is achieved, but the imaging quality is affected
Solution Approach 1:
The hot mirror component is extracted from the optical path and replaced by positioning the eye camera externally on the lens barrel. The eye camera receives infrared light reflected by the human eye that passes through the inner cavity of the lens barrel, eliminating the need for a hot mirror in the visible light optical path. This extraction prevents interference with the imaging quality while achieving eye tracking functionality.
3Volume of stationary object
If the eye camera is disposed outside the lens barrel, then the internal space of the lens barrel is saved, but the optical path alignment becomes more complex
Solution Approach 1:
The lens barrel serves as an intermediary structure that guides infrared light from the light emitting unit through the inner cavity to the eye camera positioned externally. The lens barrel's inner cavity acts as an optical channel that simplifies the alignment between the light source and the external camera, reducing the complexity of optical path alignment while maximizing space utilization.
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 design enables effective eye tracking without compromising imaging quality, facilitates maintenance, and optimizes space utilization within the lens barrel, enhancing user experience.
Implementation Method 1
the eye camera receives infrared light that is from the inner cavity of the lens barrel and that is reflected by a human eye
Implementation Method 2
incorporating a mirror reflector to adjust the optical path for eye tracking
Data Source
AI summary
A lens module and a head mounted electronic device are provided, where the lens module includes a light emitting unit, a lens barrel, and an eye camera. The light emitting unit is disposed at an end of the lens barrel. The lens module further includes a hollow mounting stage, where the mounting stage is connected to the lens barrel, a cavity of the mounting stage communicates with an inner cavity of the lens barrel, and an optical axis of the eye camera is inclined to an axial direction of the lens barrel. The lens module helps implement an eye tracking function of VR glasses based on a folded optical path, and helps reduce impact of the eye tracking function on imaging quality of the lens module.