Display Device Directional Light Control Homogeneous Luminance
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Solution Overview
Problem
Existing display devices face challenges in achieving uniform luminance on a diffusely translucent display face, leading to undesirable light source visibility and irritating contrast transitions, which affect the readability and legibility of information, especially in applications like advertising signs and traffic signs.
Innovation Solution
The solution involves orienting means added to the light source to create a directional characteristic that illuminates a diffusely reflective wall, which then reflects light to the display face, ensuring that less than 10% of the light energy directly reaches the display face, and using optical means like lenses and mirrors to achieve a homogeneous luminance distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If omnidirectional light sources are used to illuminate the display face, then the light source can provide sufficient illumination, but the light sources become visible to observers and create undesirable contrast transitions
Solution Approach 1:
The harmful omnidirectional light emission is extracted and removed, retaining only the useful directional component. The patent uses reflectors and shields to extract and eliminate light emitted in unwanted directions, allowing only light directed at the display face to pass through, thereby preventing light source visibility and contrast transitions.
Solution Approach 2:
The light source is given different emission properties in different spatial directions. By using directional reflectors and shields, the light source effectively emits light uniformly toward the display face while blocking light in other directions, creating local quality variation in the emission pattern.
2Stability of the object's composition
If a diffusely translucent plate with substantial thickness or limited light transmission is used, then luminance homogeneity is improved, but light energy loss becomes very substantial
Solution Approach 1:
Instead of making the display face itself thick or highly diffusing to achieve homogeneity, the patent inverts the approach by using thin directional reflectors and shields to control light distribution. The homogeneity is achieved through directional control rather than through substantial diffusion in the display face material.
3Stability of the object's composition
If multiple diffusely translucent plates are placed at mutual distances, then luminance homogeneity is improved, but light energy loss increases greatly
Solution Approach 1:
The patent extracts and eliminates the need for multiple thick diffusing plates by using thin directional reflectors and shields. These components selectively direct light to achieve homogeneity without the substantial light energy loss that would result from using multiple thick diffusing plates at distances.
4Stability of the object's composition
If the distance from the light source to the display face is increased, then luminance homogeneity improves, but the housing becomes voluminous with great depth
Solution Approach 1:
Instead of achieving homogeneity by increasing distance in one dimension (which会增加 housing depth), the patent uses directional reflectors and shields to control light distribution in multiple dimensions. This allows homogeneity to be achieved within a compact housing depth by manipulating light paths in angular and spatial dimensions.
5Stability of the object's composition
If a light source with a large radiating surface is used, then luminance homogeneity is improved, but costs become prohibitive
Solution Approach 1:
Instead of using a single complex light source with large radiating surface, the patent segments the lighting function into a simple light source combined with separate directional control elements (reflectors and shields). This segmentation achieves homogeneity through geometric light control rather than through a complex expensive light source design.
6Stability of the object's composition
If optical means like lenses and mirrors are designed to achieve constant luminance, then homogeneity is improved, but the design becomes complicated and expensive
Solution Approach 1:
The patent applies local quality by using simple reflectors and shields with specific directional properties positioned at key locations. Rather than designing a complex optical system, the solution uses localized directional control elements that collectively achieve uniform luminance distribution across the display face.
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 approach results in a highly homogeneous luminance on the display face, reducing the visibility of the light source and minimizing contrast transitions, thereby enhancing the visibility and legibility of information, while maintaining energy efficiency and reducing the depth of the housing.
Implementation Method 1
this at least one wall is diffusely reflective such that a part of the light incident thereon is reflected to the display face
Implementation Method 2
orienting means are added to the light source so as to obtain a directional characteristic of the light emitted by the light source
Implementation Method 3
at least one diffusely translucent display face illuminated by the light from this light source
Data Source
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AI summary
A display device such as a light box comprises: a housing; a light source accommodated in this housing; and at least one diffusely translucent display face illuminated by the light from this light source. Orienting means are added to the light source so as to obtain a directional characteristic of the light emitted by the light source such that the light source directly illuminates at least one wall almost exclusively. This at least one wall is diffusely reflective such that a part of the light incident thereon is reflected to the display face. This has an almost constant luminance as a result.