Planar Lighting Device With Intermittent Optical Elements
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Solution Overview
Problem
Conventional planar lighting devices for liquid crystal display devices face challenges in achieving uniform brightness at a low cost due to the increased mold processing costs and time required for forming optical elements like dome-shaped projections and linearly extending uneven structures on light-guiding plates.
Innovation Solution
The planar lighting device incorporates optical elements with unevenly shaped parts, such as recesses and projections, arranged intermittently on the light-guiding plate's principal faces, which are manufactured using a mold with a specific groove processing method that allows for efficient and cost-effective production, providing both light exit and diffusion patterns with varying recessed and projected amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple types of optical elements (dome-shaped projections and linearly extending uneven structures) are formed on the light-guiding plate to improve brightness uniformity, then the brightness uniformity is improved, but the mold processing costs and time increase
Solution Approach 1:
The patent combines multiple types of optical elements (dome-shaped projections and linearly extending uneven structures) into a single integrated optical element formed by one continuous groove processing operation. This merging approach maintains the brightness uniformity benefits of having multiple optical element types while eliminating the need for separate processing steps, thereby reducing mold processing cost and time.
Solution Approach 2:
The groove processing method creates a multi-functional optical element that simultaneously provides light exit functionality (through dome-shaped projections) and light diffusion functionality (through linearly extending uneven structures). This single optical element performs multiple functions that would traditionally require separate elements, reducing overall manufacturing complexity and cost while maintaining improved brightness uniformity.
2Manufacturing precision
If conventional separate processing methods are used for different optical elements, then each element can be precisely formed, but the overall production time and cost increase
Solution Approach 1:
The groove processing method performs preliminary shaping of all optical elements in a single continuous operation. The groove is formed that encompasses both dome-shaped projections and linearly extending uneven structures in one action, ensuring precise formation of all elements simultaneously while eliminating sequential processing steps, thereby maintaining manufacturing precision while significantly reducing production time.
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 enhances the uniformity of illuminating light exiting from the light-guiding plate, reduces brightness unevenness, and allows for the formation of optical elements with dual functions using a single processing method, thereby achieving improved brightness uniformity at reduced costs.
Implementation Method 1
optical elements that are provided on at least one of the pair of the principal faces and include a plurality of first elements each having an unevenly shaped part in which recesses and/or projections are repeatedly arranged
Implementation Method 2
light-guiding plate including: a light incident end face on which the light source is arranged; a facing end face facing the light incident end face; and a pair of principal faces that couple the light incident end face and the facing end face with each other
Data Source
AI summary
A planar lighting device includes: a light source; a light-guiding plate including: a light incident end face on which the light source is arranged; a facing end face facing the light incident end face; and a pair of principal faces that couple the light incident end face and the facing end face with each other; and plurality of optical elements that are provided on at least one of the pair of the principal faces and include a plurality of first elements each having an unevenly shaped part in which recesses and/or projections are repeatedly arranged, the plurality of the first elements being arranged intermittently from the light incident end face toward the facing end face.