Light Guide Body Dot Depth Variation for Uniform Illumination

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Solution Overview

Problem

Long light guide bodies face challenges in maintaining uniform light emission, leading to uneven display quality due to the need for very small prisms near the light source, which are difficult to form and result in bright spots at greater distances, causing dark areas near the light source and increased brightness further away.

Innovation Solution

A light guide body with a combination of first and second dots on its lower surface, where the depth of the first dot decreases and the second dot's depth increases as distance from the light source increases, allowing for a gradual adjustment of light emission to achieve uniform luminance without the need for extremely small prisms, thereby improving display quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the depth of prisms on the light guide body lower surface is decreased to maintain uniform light emission in long light guide bodies, then light emission uniformity is improved, but manufacturing difficulty increases due to the need for very minute prisms near the light source

Engineering Contradiction:
Improvelight emission uniformityVSAvoidprism formation difficulty
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The light guide body lower surface is divided into multiple regions along the light propagation direction, with each region having prisms of different depths. Specifically, the surface is segmented into a first region near the light source with shallower prisms and a second region farther from the light source with deeper prisms. This segmentation allows each region to be optimized independently, making manufacturing feasible while maintaining uniform light emission across the entire light guide body.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the light guide body lower surface are given different local properties in terms of prism depth. The prism depth is locally adjusted according to the position along the light propagation direction, with shallower prisms near the light source and deeper prisms farther away. This local quality variation compensates for the natural light intensity distribution, enabling uniform overall emission while avoiding the need for extremely minute prisms that would be difficult to manufacture.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If the depth of prisms is increased to improve light emission control, then light emission uniformity improves, but the arrangement interval of prisms must be increased causing uneven light distribution and deteriorated display quality

Engineering Contradiction:
Improvelight emission uniformityVSAvoidlight distribution uniformity
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The prism depth is locally optimized for each region along the light propagation direction. By making prisms shallower near the light source and deeper farther away, the invention achieves effective light emission control in each local region without needing to increase the overall arrangement interval. This local quality adjustment maintains both manufacturing precision and display quality while achieving uniform light emission.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the parameter of prism depth along the light propagation direction to optimize light emission. By gradually varying the prism depth parameter from shallower near the light source to deeper farther away, the system achieves uniform light distribution without requiring increased arrangement intervals, thereby maintaining high manufacturing precision and display quality.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If very minute prisms are formed near the light source to maintain uniform light emission in long light guide bodies, then light emission uniformity is improved, but manufacturing complexity and difficulty increase significantly

Engineering Contradiction:
Improvelight emission uniformityVSAvoidprism structure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The light guide body lower surface is segmented into multiple regions with different prism depth characteristics. Instead of using uniformly minute prisms throughout, the surface is divided such that the first region near the light source has shallower, easier-to-manufacture prisms, while the second region has deeper prisms. This segmentation reduces device complexity by avoiding the need for extremely minute prisms in the entire structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different local regions are assigned different prism depths appropriate to their position. The first region near the light source uses shallower prisms that are easier to manufacture, while the second region uses deeper prisms. This local quality differentiation eliminates the need for uniformly minute prisms throughout, significantly reducing manufacturing complexity while maintaining light emission uniformity.

Inventive Principle:
Principle #3Local 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

This configuration allows for easier manufacturing of the light guide body by reducing the depth of the second dot near the light source and increasing it further away, resulting in uniform light emission and improved display quality across the length of the light guide body.

Implementation Method 1

light is incident to an edge surface of a light guide body, and the light propagates inside the light guide body through total reflection

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

prism 8 increases spreading of light emitted from light guide body 6

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

curved surfaces 9 between the prisms... the light is diffused

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3330602B1Line illumination display device and light-guiding body
Publication Date: 2020.07.01 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3330602B1 patent drawingFigure 1
  • EP3330602B1 patent drawingFigure 2
  • EP3330602B1 patent drawingFigure 3

AI summary

To easily increase display quality of light even in a case of a long light guide body. Depth h1 of a first dot (106) is larger than depth h2 of a second dot (108) in the vicinity of a light source, and, as a location comes closer to an end on an opposite side to the light source, depth h1 of the first dot (106) is reduced, and depth h2 of the second dot (108) is increased. Therefore, it is possible to easily increase display quality of light even in a case of a long light guide body.