Light Guide Plate Tilted Separation Surfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image display apparatuses with light guide plates suffer from low light utilization efficiency due to a large amount of unnecessary light being generated in the effective area at the observer's pupil, resulting in a smaller overlap area of light beams compared to the light beam width from the exit portion.
Innovation Solution
A light guide plate with parallel first and second surfaces and tilted separation surfaces that separate incident light into reflected and transmitted components, with specific reflectance inequalities satisfied to optimize light distribution and reduce unnecessary light, thereby enhancing light utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional light guide plate is used, then light beams can be guided to observer's pupil, but light utilization efficiency significantly decreases due to large amount of unnecessary light being generated in the effective area
Solution Approach 1:
The patent applies local quality by configuring different separation surfaces with different tilt angles and reflectance characteristics at different locations within the light guide plate. Each separation surface is designed with specific local properties (different ψ angles and Rs values) to selectively reflect or transmit light rays based on their incident angles, thereby locally controlling light distribution to eliminate unnecessary light in specific regions while maintaining useful light paths.
Solution Approach 2:
The patent employs parameter changes by systematically varying the tilt angle (ψ) and reflectance (Rs) parameters of multiple separation surfaces. By adjusting these parameters across different separation surfaces, the patent optimizes the light reflection and transmission characteristics to achieve high light utilization efficiency. The specific parameter relationships (θn, ψ, Rs1mn) are carefully controlled to ensure that only necessary light reaches the observer's pupil.
2Use of energy by moving object
If multiple separation surfaces with different reflectances are used, then light distribution can be optimized, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the light guide plate into multiple regions with distinct separation surfaces, each having specific tilt angles and reflectance characteristics. This segmentation allows independent optimization of light paths for different incident angles while maintaining overall system coherence. The separation surfaces are strategically positioned to handle specific light ray bundles, reducing the complexity of managing all light paths simultaneously.
Solution Approach 2:
The patent implements multi-functionality by designing separation surfaces that can simultaneously perform multiple functions: reflecting certain incident angle ranges while transmitting others, and doing so across multiple wavelength bands. The separation surfaces are configured to handle both spatial light distribution and spectral selectivity, reducing the need for additional separate components and thereby managing device complexity while optimizing light 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 proposed solution achieves improved light utilization efficiency by optimizing the reflectance characteristics of the separation surfaces, reducing unnecessary light, and ensuring uniform light intensity distribution at the observer's pupil.
Implementation Method 1
a first separation surface, a second separation surface, and a third separation surface, each configured to separate incident light into reflected light and transmitting light
Implementation Method 2
Light beams L10, L20, and L30 emitted from pixels of an image display element 110 pass through a projection optical system 1200, enter an entrance portion 1310 at different incident angles, are deflected, and then propagate inside a light guide plate 130 at different total reflection angles
Implementation Method 3
propagate inside a light guide plate 130 at different total reflection angles α10, α20, and α30
Data Source
AI summary
A light guide plate includes a first surface and a second surface that are parallel to each other, and a first separation surface, a second separation surface, and a third separation surface, each configured to separate incident light into reflected light and transmitting light, and each tilted relative to the first surface. Predetermined inequalities are satisfied.