Transparent LED Eyepiece Integration for Direct IR Eye Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional infrared LED packages in optical head-mounted displays (OHMDs) are large and obstructive, requiring higher power for indirect illumination, limiting glint patterns and increasing system complexity, while integrated arrays on the eyepiece enable direct illumination but face challenges in precise alignment and visibility.
Innovation Solution
A transparent LED array is integrated onto a transparent substrate with conductive traces and bond pads, encapsulated by a transparent molded material without adhesives, allowing direct illumination and precise alignment for improved eye tracking and display capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional infrared LED packages are used in peripheral frame, then electrical connection is achieved, but field of view is obstructed and eye tracking accuracy is reduced
Solution Approach 1:
The patent transitions LED placement from the peripheral frame (2D plane) to the eyepiece surface (3D integration), allowing LEDs to be positioned in a different spatial dimension that does not obstruct the user's field of view while maintaining electrical connection through conductive traces on the eyepiece substrate
Solution Approach 2:
The patent extracts the LEDs from the peripheral frame structure and integrates them directly onto the eyepiece, separating the illumination function from the structural frame and allowing independent optimization of each component's position and function
2Illumination intensity
If conventional infrared LED packages are used in peripheral frame, then electrical connection is achieved, but higher output power is required for indirect illumination
Solution Approach 1:
The patent positions LEDs in advance on the eyepiece surface to enable direct illumination of the cornea, eliminating the need for indirect light paths and reducing the energy required to achieve the necessary corneal irradiance for accurate eye tracking
Solution Approach 2:
The patent replaces the indirect optical path (mechanical light reflection off frame surfaces) with a direct optical path from LED to cornea, substituting a complex indirect illumination system with a simpler direct illumination approach that consumes less power
3Adaptability or versatility
If conventional infrared LED packages are used in peripheral frame, then electrical connection is achieved, but glint pattern range is restricted
Solution Approach 1:
The patent divides the illumination function into multiple independent mini- or micro-LEDs that can be individually controlled, allowing each LED to contribute to different aspects of glint pattern generation and enabling a wider range of patterns through selective activation
Solution Approach 2:
The patent designs the LED array on the eyepiece to serve multiple functions: generating various glint patterns for eye tracking, providing visible information display to the user, and maintaining electrical connection through the substrate, reducing overall system complexity through multi-functionality
4Measurement precision
If mini- or micro-LEDs are integrated onto eyepiece, then direct illumination is achieved, but alignment precision and visibility are challenged
Solution Approach 1:
The patent merges the LED array integration with the eyepiece manufacturing process itself, incorporating LEDs directly into the optical element during fabrication rather than as a separate assembly step, which ensures precise alignment and maintains visibility while simplifying manufacturing
Solution Approach 2:
The patent uses the transparent conductive oxide traces and bonding structures as intermediary elements that facilitate both precise electrical connection and optical transparency, allowing mini- or micro-LEDs to be aligned and connected with high precision while maintaining the optical properties of the eyepiece
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 approach reduces system power consumption, enhances glint pattern range, and improves cosmetic appearance with high transparency and reduced reflections, while enabling precise alignment and cost-effective manufacturing.
Implementation Method 1
The substrate with the LEDs and the traces, bond pads, or land pads can be inserted into a mold, and either molten thermoplastic material or thermoset material liquid precursors can then be injected into the mold
Implementation Method 2
One technique for tracking eye movement relies on analysis of infrared (IR) light that is directed toward the user's eye, scattered or reflected from the user's eye, and detected by one or more optical detectors
Implementation Method 3
Conventional infrared LED packages can be several square millimeters in size
Implementation Method 4
The electrically conductive layer can be transparent, or the traces, bond pads, or land pads can be sufficiently small and sufficiently sparse, to enable visual observation of a scene through the substrate along a sightline that passes through the traces, bond pads, or land pads
Implementation Method 5
The molded material is molded directly onto the substrate surface, without any intervening adhesive, and encapsulates the LEDs and the traces, bond pads, or land pads
Data Source
AI summary
A light-emitting apparatus includes: a transparent substrate; electrically conductive traces, bond pads, or land pads on the substrate; LEDs; and transparent molded material. The traces, bond pads, and land pads can be transparent, or can be sufficiently small and sufficiently sparse, to enable visual observation of a scene through the substrate and the traces, bond pads, or land pads. The LEDs are connected to the bond pads, and are sufficiently small and sparse so as to enable visual observation of the scene through them. The molded material can be a thermoplastic material or a thermoset material and is molded directly onto the substrate surface, without any intervening adhesive, and encapsulates the LEDs and the traces, bond pads, or land pads. Molten material or liquid precursors are injected into a mold enclosing the substrate with the LEDs and the traces, bond pads, or land pads.