Curved Light Guide Holograms for Uniform Display Luminance
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Solution Overview
Problem
Existing optical waveguides, such as those described in PTL 1, suffer from image unevenness due to varying Fresnel reflection rates when light passes from one waveguide to another, leading to decreased image quality on display mediums like windshields.
Innovation Solution
A display device comprising a system of curved light guides with distinct output hologram elements, each with different light quantity distributions, to compensate for Fresnel losses and maintain uniform image luminance across the display medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple optical waveguides are used to expand the display area, then the display area is increased, but image unevenness occurs due to varying Fresnel reflection rates
Solution Approach 1:
The patent applies local quality by adjusting the light quantity distribution individually for each optical waveguide based on its specific position and Fresnel reflection characteristics. Each waveguide's light guide plate has a tailored light quantity distribution pattern that compensates for its local Fresnel losses, ensuring uniform image appearance across the entire expanded display area despite using multiple waveguides with different reflection rates.
Solution Approach 2:
The patent implements parameter changes by modifying the light quantity distribution parameters for each optical waveguide. By calculating and adjusting the light quantity distribution based on position information and Fresnel reflection rates, the system changes the optical parameters to compensate for varying reflection characteristics across different waveguides, thereby maintaining image uniformity while expanding the display area.
2Adaptability or versatility
If curved light guides are used, then the display can be adapted to curved surfaces, but light quantity distribution becomes non-uniform due to Fresnel losses
Solution Approach 1:
The patent applies local quality by calculating and adjusting the light quantity distribution for each region of the curved light guide based on its specific position and orientation. Different portions of the curved light guide have different light quantity distribution characteristics tailored to their local geometry and Fresnel reflection properties, ensuring uniform illumination across the entire curved display surface.
Solution Approach 2:
The patent implements preliminary action by pre-calculating the light quantity distribution for each optical waveguide before light transmission occurs. The control device determines the appropriate light quantity distribution based on position information and Fresnel reflection rates, and adjusts the light guides accordingly in advance, compensating for expected Fresnel losses before they affect the displayed image.
3Manufacturing precision
If light quantity distribution is adjusted for each waveguide, then image uniformity is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by implementing an automatic control system that autonomously calculates and adjusts the light quantity distribution for each optical waveguide based on its position and Fresnel reflection characteristics. The control device automatically determines the appropriate light distribution parameters and applies them without manual intervention, reducing the operational complexity despite the increased number of adjustable parameters.
Solution Approach 2:
The patent implements parameter changes through a systematic approach where the control device adjusts light quantity distribution parameters based on calculated Fresnel reflection rates and position information. By automating the parameter adjustment process and using position-based calculations, the system manages the complexity of multiple waveguides through a unified control methodology rather than individual manual adjustments.
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 image unevenness and maintains image quality by adjusting light quantity distributions and angles within each light guide, ensuring consistent image projection despite curved shapes and Fresnel losses.
Implementation Method 1
a first output hologram element from which the image light exits; and a second output hologram element from which the image light exits
Implementation Method 2
each of the first light guide and the second light guide is in a curved shape, the image light emitted from the image generating device enters the first light guide
Data Source
AI summary
A display device incudes: an image generating device that generates light that indicates an image (image light); a first light guide that includes a first output hologram element from which the image light exits; and a second light guide that includes a second output hologram element from which the image light exits. Each of the first light guide and the second light guide is in a curved shape. The image light emitted from the image generating device enters the first light guide. A portion of the 10 image light that has entered the first light guide enters the second light guide. A light quantity distribution of the image light exiting the first output hologram element is different from a light quantity distribution of the image light exiting the second output hologram element.