See-Through Display Optics With Polarizers and Light Traps
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Solution Overview
Problem
Head-mounted displays are sensitive to the effects of stray light, which reduces the sharpness and contrast of the displayed image, causing black areas to appear gray and affecting the see-through view of the environment.
Innovation Solution
Implementing optical configurations that manage stray light by using polarized light sources, reflective polarizers, and light traps to separate image and dark state light paths, ensuring high contrast and deep blacks in the displayed image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional optical configurations are used in head-mounted displays, then the device structure is simple, but stray light reduces image sharpness and contrast
Solution Approach 1:
The optical system is segmented into distinct functional components: polarized light sources for generating image light, reflective polarizers for separating light paths, and light traps for capturing stray light. This segmentation allows each component to be optimized independently while working together to eliminate stray light and improve image quality.
Solution Approach 2:
Polarized light sources and reflective polarizers act as intermediary elements between the light source and the display medium. These intermediaries control and separate the light paths, ensuring that only the intended image light reaches the display while stray light is redirected to light traps.
2Manufacturing precision
If conventional optical configurations are used, then the device structure is simple, but black areas appear gray reducing contrast
Solution Approach 1:
The system converts the potentially harmful stray light into a beneficial component by redirecting it to light traps. The light traps capture what would otherwise be harmful stray light, converting it into a controlled element that improves contrast by ensuring only pure image light reaches the display medium.
Solution Approach 2:
Stray light is extracted from the optical path through reflective polarizers and directed to dedicated light traps. This extraction removes the harmful element from the main light path, preventing it from degrading the contrast of black areas in the displayed image.
3Adaptability or versatility
If stray light is not reduced, then the optical system is simple, but the see-through view of the environment is degraded
Solution Approach 1:
The optical system separates the functions of image display and environmental view transmission through distinct optical paths. The polarized light sources and reflective polarizers create separate pathways that prevent stray light from interfering with either the displayed image or the see-through environmental view.
Solution Approach 2:
Polarized light sources and reflective polarizers serve as intermediary elements that manage light paths carefully. They ensure that light from the environment and light from the display medium travel through separate pathways, preventing interference and maintaining high-quality see-through views.
4Manufacturing precision
If complex optical configurations are used to manage stray light, then image sharpness and contrast improve, but the device complexity increases
Solution Approach 1:
The complex task of stray light management is segmented into manageable components: polarized light sources, reflective polarizers, and light traps. Each component performs a specific function, making the overall complex system easier to design, manufacture, and maintain while achieving superior image quality.
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 solution effectively reduces stray light, enhancing image sharpness and contrast, providing clear see-through views by maintaining deep blacks and high brightness in head-mounted displays.
Implementation Method 1
polarized light sources, reflective polarizers
Implementation Method 2
reflective polarizers
Implementation Method 3
light traps to separate image and dark state light paths
Data Source
AI summary
Aspects of the present invention relate to providing see-through computer display optics. In embodiments, a wearable head device comprises a frame, a first optical module comprising a first reflecting surface, a second optical module, electronic components, and a heat sink. The electronic components may be disposed adjacent to the frame and further disposed between the first reflecting surface and the second optical module. The electronic components may comprise a processor. The electronic components may be configured to rest a first distance from the head of a user of the wearable head device. The heat sink may be disposed between the first reflecting surface and the second optical module and configured to rest a second distance from the head of the user, the second distance greater than the first distance. The heat sink may be thermally coupled to the processor.