Light Guide Plate Prisms with Reflection Layer for Stray Light Control
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Solution Overview
Problem
Existing aerial display devices suffer from stray light issues, which narrow the viewing angle and result in reduced visibility due to the configuration of light guides and emission structures.
Innovation Solution
A display device is designed with a light guide plate that includes a light reflection or absorption layer on certain optical surfaces to prevent stray light, using prisms to reflect or refract image light rays and a mask with slits to ensure only intended light reaches the viewer, thereby preventing ghost images and allowing wider viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light guide plate with emission structures is used to display images in the air, then image visibility is improved, but stray light is generated that narrows the viewing angle
Solution Approach 1:
The patent applies this principle by converting the harmful stray light into beneficial reflected light. The reflection layer, positioned at specific depths within the light guide plate, captures stray light that would otherwise degrade image quality and redirects it toward the viewer. This transforms the harmful scattering effect into a useful light source that enhances image visibility while maintaining wide viewing angles.
Solution Approach 2:
The reflection layer acts as an intermediary element between the emission structures and the external environment. It mediates the interaction between stray light and the viewer by selectively reflecting light at controlled depths, thereby preventing direct stray light from reaching the viewer while still allowing intended image light to pass through. This intermediary layer resolves the contradiction by filtering harmful effects while preserving beneficial light transmission.
2Illumination intensity
If emission structures are added to the light guide plate to improve image formation, then image quality is enhanced, but device complexity increases
Solution Approach 1:
The patent merges the functions of image formation and stray light control into a single integrated light guide plate structure. The emission structures and reflection layer are combined within the same optical component, eliminating the need for separate stray light filtering elements. This integration maintains image quality while reducing overall device complexity by consolidating multiple functions into one structure.
Solution Approach 2:
The light guide plate is designed with multi-functionality, serving both as the medium for image light transmission and as the structure for stray light reflection. The emission structures and reflection layer work together to perform multiple functions: guiding image light, reflecting stray light, and controlling light distribution. This universal design reduces the need for additional components, thereby simplifying the overall device while enhancing 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 prevents stray light and ghost images, enhancing visibility and maintaining image quality across a broader viewing angle by controlling light reflection and absorption within the display device.
Implementation Method 1
a light guide plate 14 having a light exit surface 14c for emitting the image light ray and a bottom surface 14b facing the light exit surface
Implementation Method 2
emits the image light ray, reflected or refracted by each of a plurality of emission structures provided on the light guide plate
Implementation Method 3
emits the image light ray, reflected or refracted by each of a plurality of emission structures provided on the light guide plate
Implementation Method 4
a light reflection layer or a light absorption layer is formed on at least one optical surface out of the optical surfaces in the emission structure
Implementation Method 5
a light reflection layer or a light absorption layer is formed on at least one optical surface out of the optical surfaces in the emission structure
Data Source
AI summary
Provided is a display device that prevents generation of stray light and has excellent visibility. In a display device (1) that makes an image light ray enter from an end face of a light guide plate (14) and emits the image light ray, reflected or refracted by each of a plurality of emission structures (prisms 141) provided on the light guide plate, from a light exit surface (14c) of the light guide plate, a light reflection layer or a light absorption layer is formed on at least one optical surface among optical surfaces provided on the emission structure (the prism 141) except for an optical surface that reflects or refracts the image light ray.