Overlapping Diffractive Light Guides for Display Brightness Range
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Solution Overview
Problem
Optical apparatuses, such as exit pupil expanders, struggle to maintain high dynamic range across varying light conditions, particularly in environments like nighttime or bright sunlight, affecting the brightness and clarity of images in displays.
Innovation Solution
The apparatus employs a stacked configuration of light guiding means with in-coupling and out-coupling diffractive elements, allowing for the overlay of images from multiple light engines to control brightness, with one engine operating independently to enhance image contrast and brightness levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single light engine is used in the optical apparatus, then the device complexity is reduced, but the dynamic range and brightness control capability deteriorate
Solution Approach 1:
The optical apparatus is divided into multiple light guiding means (first light guiding means 101A and second light guiding means 101B), each with its own light engine. This segmentation allows independent control of brightness for different portions of the output beam, enabling dynamic range adjustment without requiring complete system redesign.
Solution Approach 2:
The patent introduces a temporal dimension by enabling alternating operation of multiple light engines. The system can switch between different light guiding means or operate them in sequence, adding time-based control to the spatial arrangement of optical components. This allows dynamic brightness adjustment without increasing physical complexity.
2Adaptability or versatility
If multiple light guiding means are used to improve dynamic range, then the brightness control capability is improved, but the device complexity increases
Solution Approach 1:
Multiple light guiding means are merged into a single optical apparatus with overlapping output beams. The first and second light guiding means are positioned such that their out-coupled beams combine, allowing additive brightness control. This merging approach achieves dynamic range improvement while sharing common optical infrastructure.
Solution Approach 2:
Each light guiding means is designed to be multi-functional, capable of operating independently or in combination with others. The overlapping beam configuration allows the system to function as a single unit or as multiple independent channels, providing versatility without requiring completely separate systems for each function.
3Illumination intensity
If the out-coupling diffractive means of different light guiding means overlap, then the image brightness is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The overlapping region of the out-coupled beams is specifically optimized for additive brightness enhancement. Rather than requiring perfect alignment across the entire beam path, the design focuses precision requirements on the localized overlap region where brightness enhancement occurs. This allows tolerance in other areas of the optical path.
Solution Approach 2:
The system incorporates automatic brightness adjustment capability that can compensate for minor alignment variations. By detecting ambient light levels and user preferences, the control system automatically adjusts the operation of individual light guiding means to maintain optimal brightness, reducing the impact of manufacturing tolerances on final performance.
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 configuration enables adjustable brightness control, improving the dynamic range and image quality by allowing independent operation of light engines based on ambient light, user preference, or content importance, resulting in enhanced image clarity and reduced color breakup.
Implementation Method 1
in-coupling diffractive means configured to in-couple one or more input beams of light into the first light guiding means from a first light engine
Implementation Method 2
expanding means configured to expand the one or more input beams of light
Implementation Method 3
out-coupling diffractive means configured to out-couple the one or more expanded beams of light from the first light guiding means
Data Source
AI summary
An apparatus for controlling brightness of images includes: a first light guide including an in-coupling diffraction grating configured to in-couple input beams of light from a first light engine, an expanding grating configured to expand the input beams of light, and an out-coupling diffraction grating configured to out-couple the expanded beams of light; and a second light guide including at least; an in-coupling diffraction grating configured to in-couple input beams of light from a second light engine, an expanding grating configured to expand the input beams of light, and an out-coupling diffraction grating configured to out-couple the expanded beams of light. The out-coupling diffraction grating of the first light guide at least partially overlaps the out-coupling diffraction grating of the second light guide so that images are overlaid to control brightness of images provided by the apparatus.