Light Guide With Opaque Peripheral Part For Uniform Illumination
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Solution Overview
Problem
Existing light guides for liquid crystal display devices in timepieces suffer from light leaks and non-homogeneous illumination, making them difficult to produce industrially and resulting in unsatisfactory aesthetic and functional performance.
Innovation Solution
A light guide is designed with a transparent central part for light extraction and an opaque peripheral part that surrounds the central element, eliminating lateral light leaks and integrating mounting and fixing components, thus avoiding complex painting operations and enhancing illumination intensity and homogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a point light source is placed on the back of the liquid crystal display device, then the display device can be illuminated, but the illumination is non-uniform with intense halos at the light source location
Solution Approach 1:
A light guide plate is introduced as an intermediary component between the point light source and the liquid crystal display device. The light guide plate receives light from the point source and redistributes it uniformly across the display surface through its optical properties and microstructures, eliminating the halo effect while maintaining illumination intensity.
Solution Approach 2:
The light guide plate is segmented into a transparent central part for light extraction and an opaque peripheral part for containing stray light. This segmentation allows the central region to provide uniform illumination while the peripheral region prevents light leakage, resolving the contradiction between illumination quality and structural simplicity.
2Object-affected harmful factors
If the upper surface of the light guide is split into peripheral and useful surfaces with absorbent material applied, then light leakage is reduced, but the manufacturing process becomes long and complex
Solution Approach 1:
The opaque peripheral part is integrated into the light guide plate structure during the molding process itself, before the illumination function is activated. This preliminary incorporation of light-controlling functionality eliminates the need for subsequent painting operations, reducing manufacturing time while effectively preventing light leakage.
Solution Approach 2:
The light guide plate combines multiple functions into a single component: the transparent central part provides light extraction, while the opaque peripheral part contains stray light. This merging of illumination and light containment functions into one molded piece eliminates separate manufacturing steps for applying absorbent material, reducing both time and complexity.
3Object-affected harmful factors
If the lateral edge of the light guide is chamfered, then light leakage is partially reduced, but light leaks cannot be completely avoided and the aesthetic appearance is compromised
Solution Approach 1:
Different regions of the light guide plate are assigned different optical properties: the central part remains transparent for light extraction, while the peripheral part is made opaque to contain stray light. This local differentiation ensures that light leakage is completely prevented at the edges without compromising the illumination quality in the central region, achieving both aesthetic appearance and reliable light containment.
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 provides more intense and homogeneous illumination by preventing light leaks and simplifying the manufacturing process, reducing production time and costs while maintaining high-quality light distribution.
Implementation Method 1
an opaque peripheral part made of a material absorbing the light in the mass which surrounds the central element
Implementation Method 2
Optical microstructures called light extractors, the function of which is to uniformly extract over the entire surface of the light guide the light injected into the light guide by the light source
Data Source
Figure 1
Figure 2~4
Figure 5
AI summary
Light guide into which is injected the light produced by a light source (38) optically coupled with the light guide (24), the light guide (24) comprising a first central part (26) made of a transparent material in which are structured light extractors (36) through which the light produced by the light source (38) is extracted from the light guide, and a second peripheral part (28) made of a light-absorbing material and surrounding the central part (26), the peripheral part (28) being integral with the central part (24).