AR Display Protective Filter for Eye-Tracking IR Blocking
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Solution Overview
Problem
Wearable devices such as HMDs and AR glasses require high-resolution displays to prevent user dizziness, but near-infrared light used for eye tracking can harm the eyes over time.
Innovation Solution
Incorporating a protective filter with a liquid crystal layer that blocks harmful near-infrared light and adjusts transmission areas based on the user's eye shape to protect the eyes while enabling high-resolution foveated rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If near-infrared light is emitted for eye tracking, then eye tracking function is enabled, but harmful effects on user's eyes occur
Solution Approach 1:
A protective filter is introduced as an intermediary component between the near-infrared light source and the user's eyes. This filter selectively blocks harmful near-infrared wavelengths while permitting useful visible light to pass through, thereby enabling eye tracking functionality without exposing the eyes to harmful radiation levels
Solution Approach 2:
The protective filter is designed with specific optical parameters that allow it to differentiate between near-infrared light (harmful) and visible light (useful). By controlling the filter's transmission characteristics in different wavelength ranges, the system maintains eye tracking capability while eliminating harmful effects
2Manufacturing precision
If high-resolution display is provided, then user dizziness is prevented, but device complexity increases
Solution Approach 1:
The system implements variable resolution display where different regions of the display have different resolutions. The central vision area (fovea) receives high-resolution content while peripheral areas use lower resolution, matching the human visual system's characteristics. This approach achieves high effective resolution where needed while reducing overall device complexity and computational load
3Productivity
If foveated rendering is applied, then display efficiency is improved, but transmission area control complexity increases
Solution Approach 1:
The protective filter incorporates a liquid crystal layer that can dynamically change its optical properties in response to control signals. This allows the transmission and blocking areas to be adjusted in real-time based on the user's eye position and gaze direction, enabling efficient foveated rendering while maintaining adaptability to different viewing conditions
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
Protects the user's eyes from near-infrared light while maintaining high-resolution display capabilities through foveated rendering technology.
Implementation Method 1
The liquid crystal layer forms a blocking area blocking a portion of a light path of the near-infrared light emitted towards the user's eyes
Implementation Method 2
a transmission area that does not block the light path of the near-infrared light emitted towards the user's eyes
Implementation Method 3
A reflective member reflects the display light emitted from the display panel in a direction towards the glasses
Data Source
AI summary
A display device includes glasses disposed to correspond to a display area of a lens. A display panel emits display light. A reflective member reflects the display light emitted from the display panel in a direction towards the glasses. A light source unit emits near-infrared light towards a user's eyes for tracking a user's eyes. A protective filter includes a liquid crystal layer. The protective filter blocks a portion of a light path of the near-infrared light emitted towards the user's eyes from the light source unit. A processor controls the liquid crystal layer. The liquid crystal layer forms a blocking area blocking the portion of the light path of the near-infrared light emitted towards the user's eyes and a transmission area that does not block the light path of the near-infrared light emitted towards the user's eyes.