Laminated Light Guide Collimator with Grating Interface
Solution Overview
Problem
Conventional transmissive and reflective electronic displays face challenges in energy efficiency and light distribution, particularly in low-light conditions, due to limitations in backlight and frontlight designs, which affect user experience and display quality.
Innovation Solution
A laminated collimator system that includes a light guide with a composite optical coating and a beam steering structure, capable of distributing light from a small-area light source to a larger display area, modulating light intensity, and correcting excessive light angles, thereby enhancing illumination uniformity and reducing stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional backlights and frontlights are used in LCD displays, then the display can be illuminated, but energy efficiency is compromised and light distribution is uneven
Solution Approach 1:
The light guide is divided into multiple segments with different refractive indices arranged in a laminated structure. Each layer segments the light path and contributes to directional control, achieving both energy efficiency and uniform light distribution through the cumulative effect of multiple segmented interfaces.
Solution Approach 2:
The patent changes the refractive index parameter by using multiple layers with different refractive indices (e.g., 1.49, 1.59, 1.65) to control light propagation. This parameter variation enables precise control over light direction and distribution, resolving the contradiction between energy efficiency and illumination uniformity.
2Area of stationary object
If a light guide is used to direct light from a small-area light source to a larger display area, then illumination coverage is improved, but stray light and back-scattered light increase
Solution Approach 1:
The light guide employs a composite structure with multiple materials of different refractive indices. This composite material approach enables precise control over light propagation by leveraging the specific optical properties of each material, thereby expanding light coverage area while minimizing stray and back-scattered light through optimized material selection and layer configuration.
3Illumination intensity
If traditional blazed gratings are used for light distribution, then light can be directed, but collimation is insufficient and stray light levels remain high
Solution Approach 1:
The patent replaces mechanical grating structures with an optical solution based on refractive index differences. Instead of using physical grooves or mechanical elements to direct light, the invention uses a laminated structure of optical materials with different refractive indices to achieve the same light directionality function, resulting in superior collimation and reduced stray light through pure optical refraction mechanisms.
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 laminated collimator achieves higher collimation and lower stray light levels compared to traditional blazed gratings, providing improved light distribution and reduced back-scattered light, enhancing display quality and user experience across various lighting conditions.
Implementation Method 1
a light guide to direct light from a light source onto or through a display
Implementation Method 2
The appearance and quality of a display can affect the user's experience with the electronic device
Implementation Method 3
a beam steering structure, capable of distributing light from a small-area light source to a larger display area, modulating light intensity
Implementation Method 4
correcting excessive light angles, thereby enhancing illumination uniformity and reducing stray light
Implementation Method 5
The laminated collimator achieves higher collimation and lower stray light levels compared to traditional blazed gratings, providing improved light distribution and reduced back-scattered light
Data Source
AI summary
The subject matter disclosed herein relates to an optical device comprising: a light guide film to transport light rays via total internal reflection; a first optical layer covering at least a portion of a first side of the light guide film, the first optical layer to receive an exiting portion of the light rays; a second optical layer covering at least a portion of the first optical layer; and a grating pattern located at an interface between the first optical layer and the second optical layer to out-couple light rays travelling in the light guide film, wherein the grating pattern is configured so that the exiting portion of the light rays transmit through the grating pattern twice before being total internally reflected by the grating pattern.