Optical Element Divergence Angle for Display Brightness Uniformity
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Solution Overview
Problem
Existing display systems for mobile objects, such as vehicles, experience variations in brightness when the viewer's eyepoint location changes, affecting the visibility of projected images.
Innovation Solution
A display system that includes an optical element and an imaging optical system, where the image formed by projecting diverging light through the optical element is designed to maintain sufficient brightness distribution by satisfying the condition tan θ≥(T×B)/(S×O), with θ being the divergence angle, T the distance between the image forming optical system and the formed image, B the eye box range, and S the distance between the formed image and the viewer's viewpoint, and O the distance between the optical element and the image forming optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the divergence angle of the optical element is increased to maintain brightness at the edges of the eye box, then the brightness uniformity improves, but the eye box range becomes larger which may cause light loss
Solution Approach 1:
The patent applies parameter changes by precisely controlling the divergence angle θ of the optical element to satisfy the inequality tan θ≥(T×B)/(S×O). This parameter optimization ensures that light is distributed uniformly across the eye box while minimizing excessive light loss, achieving a balance between brightness uniformity and light efficiency.
2Ease of operation
If the eye box range B is increased to allow greater viewer movement, then the ease of operation improves, but the brightness at the edges of the eye box decreases
Solution Approach 1:
The patent resolves this contradiction by optimizing the divergence angle θ to satisfy tan θ≥(T×B)/(S×O). This parameter adjustment ensures that even as the eye box range B increases to accommodate greater viewer movement, the brightness at the edges of the eye box is maintained at acceptable levels through proper light distribution.
3Manufacturing precision
If the distance T between the image forming optical system and the formed image is increased to improve image quality, then the manufacturing precision improves, but the brightness at the viewer's position decreases
Solution Approach 1:
The patent addresses this contradiction by adjusting the divergence angle θ to satisfy the inequality tan θ≥(T×B)/(S×O). When the distance T is increased to improve image quality, the divergence angle is相应 adjusted to ensure that sufficient light reaches the viewer's position, maintaining acceptable brightness levels despite the increased distance.
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 reduces variations in brightness when the viewer moves their eyepoint, ensuring consistent image brightness across the viewing area, even at the edges of the eye box.
Implementation Method 1
an optical element through which light diverges
Implementation Method 2
an optical element through which light diverges
Data Source
AI summary
A display system includes an optical element through which light diverges and an imaging optical system configured to form an image by projecting diverging light diverging through the optical element. In the display system, the image formed by the imaging optical system is visually recognized by a viewer, and a condition in an equation tan 0≥(T×B)/(S×O) is satisfied, where θ denotes a divergence angle of the optical element, T denotes distance between the image forming optical system and the formed image, B denotes a range of an eye box that is an area through which the formed image can visually be recognized, S denotes distance between the formed image and a viewpoint of the viewer of the formed image, and O denotes distance between the optical element and the image forming optical system. In the above equation, each distance indicates length of an optical path that passes through a center of an image formed by the light when an object is observed from a reference eyepoint.