Tilted Prismatic Retroreflective Elements for Image Brightness
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Solution Overview
Problem
Existing image display devices equipped with retroreflective members suffer from insufficient brightness and difficulty in visual recognition of images due to degraded entrance angle characteristics of prismatic retroreflective elements.
Innovation Solution
An image display device incorporating a retroreflective member with prismatic elements having a tilt angle of the optical axis exceeding zero degrees, specifically designed to enhance entrance angle characteristics, comprising a base material layer and prismatic retroreflective elements such as triangular pyramid or full cube corner elements, with a refractive index of 1.45 to 1.70, and a coefficient of retroreflection of 600 cd·lx·m−2 or more at an observation angle of 0.2° and entrance angle of 5°.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If prismatic retroreflective elements with zero-degree optical axis tilt are used, then the structure is simple and manufacturing is easy, but the entrance angle characteristics are degraded resulting in insufficient brightness
Solution Approach 1:
The patent applies parameter changes by tilting the optical axis of the prismatic retroreflective elements at a specific angle (θ) relative to the normal of the retroreflective member surface. This angular parameter modification improves entrance angle characteristics and image brightness while maintaining the fundamental prismatic structure, thus resolving the contradiction between brightness and structural complexity.
2Area of stationary object
If the image output device size is reduced, then the overall device size decreases, but the image brightness and quality deteriorate
Solution Approach 1:
By modifying the optical axis tilt angle parameter of the retroreflective elements, the system achieves improved light collection and retroreflection efficiency. This allows a smaller image output device to produce sufficiently bright images, effectively resolving the contradiction between device size and image brightness.
3Manufacturing precision
If conventional retroreflective elements are used, then manufacturing is straightforward, but the image forming characteristics are poor due to degraded entrance angle performance
Solution Approach 1:
The invention modifies the optical axis tilt angle parameter of existing retroreflective elements, which can be achieved through standard manufacturing techniques such as molding or coating processes. This parameter adjustment significantly improves image forming characteristics without requiring fundamentally new manufacturing methods, thus resolving the contradiction between manufacturing precision and ease of manufacture.
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 significantly brightens images and improves image forming characteristics, enabling better visibility and maintaining image quality even with reduced image output device size, while reducing the thickness of the display device.
Implementation Method 1
a retroreflective member configured to retroreflect at least one of a light beam mirror-reflected off the one face of the half mirror and a light beam transmitted through the one face of the half mirror
Implementation Method 2
A light beam entered to the prismatic retroreflective element is in turn reflected off the three planes, and then retroreflected to the direction of the light source
Data Source
AI summary
An image display device includes a half mirror, an image output device configured to output a light beam to one face of the half mirror, and a retroreflective member configured to retroreflect at least one of a light beam mirror-reflected off the one face of the half mirror and a light beam transmitted through the one face of the half mirror. The retroreflective member has a base material layer and a plurality of prismatic retroreflective elements formed on one face or two faces of the base material layer. The tilt angle of the optical axis of the prismatic retroreflective element exceeds zero degree.