Light Guide Plate Prism Recesses for Luminance Uniformity
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Solution Overview
Problem
Existing lighting devices with light guide plates suffer from luminance unevenness across the light exit surface, which affects display quality in devices like liquid crystal display devices.
Innovation Solution
Incorporating light collecting portions and exit light reflection portions on the light guide plate, with the exit light reflection portions placed in recessed portions between adjacent light collecting portions, to optimize light distribution and reduce luminance unevenness by controlling the reflection and collection of light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If exit light reflection portions are placed in the apex portions of light collecting portions, then light collection efficiency is improved, but luminance unevenness occurs
Solution Approach 1:
The patent extracts the exit light reflection portions from the apex portions of the light collecting portions and relocates them to the recessed portions between adjacent light collecting portions. This separation prevents the concentration of reflected light at the apex portions, thereby eliminating luminance unevenness while maintaining effective light reflection and collection
Solution Approach 2:
The patent applies different functional characteristics to different regions: the apex portions of light collecting portions are optimized for light collection, while the recessed portions between them are optimized for light reflection. This local differentiation ensures that each region performs its specific function without causing luminance unevenness
2Illumination intensity
If light collecting portions are used to increase front luminance, then luminance unevenness is reduced, but device complexity increases
Solution Approach 1:
The patent merges the light collecting portions and exit light reflection portions into a single integrated light guide plate structure. This combination achieves uniform light distribution and enhanced front luminance without requiring separate components, thereby avoiding increased device complexity
Solution Approach 2:
The light guide plate serves multiple functions simultaneously: it guides light from the light sources, collects light through the light collecting portions, reflects light through the exit light reflection portions, and distributes light uniformly across the light exit surface. This multi-functionality reduces the need for additional components
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 front luminance and reduces luminance unevenness across the light exit surface, improving display quality by ensuring consistent light distribution.
Implementation Method 1
Light emitted by the point light sources enters the light guide plate and travels within the light guide plate. The light guide plate has a lighting surface on a plate surface opposite from the light exit surface. Light is reflected by the lighting surface toward the light exit surface.
Implementation Method 2
an exit light reflection portion provided in a recessed portion that is formed by two adjacent light collecting portions and configured to reflect light travelling within the light guide plate and facilitate exiting of light from the light guide plate
Implementation Method 3
light collecting portions on one of the light exit surface and the opposite plate surface, projecting from the one of the light exit surface and the opposite plate surface and arranged in a predetermined direction and configured to collect light toward in a normal direction of the light exit surface
Data Source
AI summary
A lighting device includes LEDs 17, and a light guide plate 19 including an edge surface and a pair of plate surfaces, a part of the edge surface being a light entrance surface 19B through which light from the LEDs 17 enters, and one of the plate surfaces being a light exit surface 19A through which the light exits and another one of the plate surfaces being an opposite plate surface 19C opposite from the light exit surface 19A. The light guide plate 19 includes prism portions 51 on the opposite plate surface 19C, projecting from the opposite plate surface 19C and arranged in the X-axis direction and configured to collect light toward in a normal direction of the light exit surface 19A, and an exit light reflection portion 60 provided in a recessed portion 52 that is formed by two adjacent prism portions 51 and configured to reflect light travelling within the light guide plate 19 and facilitate exiting of light from the light guide plate 19.