Light Guide Plate Recessed LED Alignment for Display Brightness Uniformity
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Solution Overview
Problem
Conventional illumination units using split light guide plates for areal control in display apparatuses suffer from uneven brightness due to the light emission characteristics of LEDs, particularly at the edges and between LEDs, which are not adequately addressed by existing solutions.
Innovation Solution
A light guide plate with recessed portions for LED placement and a dimming pattern that varies in size and shape along the light emitting surface, with smaller patterns at the edges and larger patterns in the center, to optimize light distribution and reduce uneven brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a light guide plate is split into a plurality of stages for areal control, then local dimming capability is improved, but uneven brightness is generated between regions due to light emission direction
Solution Approach 1:
The patent applies local quality by providing light shielding members at specific locations where uneven brightness occurs (between light guide plates and at light incident portions) rather than uniformly across the entire structure. The light shielding members are strategically positioned to address local brightness issues while preserving the overall areal control functionality.
Solution Approach 2:
The patent introduces asymmetric elements by adding light shielding members that create intentional asymmetry in the light path. This asymmetry compensates for the asymmetric light distribution caused by LED emission characteristics, thereby achieving more uniform brightness across different regions.
2Illumination intensity
If light shielding members are added to reduce uneven brightness, then brightness uniformity is improved, but device complexity increases
Solution Approach 1:
The patent merges the light shielding members with the light guide plate structure itself, making them integral components rather than separate added elements. This integration reduces device complexity while maintaining the brightness uniformity improvement.
Solution Approach 2:
The light shielding members serve multiple functions: they reduce uneven brightness between light guide plates, control light distribution at light incident portions, and work across all regions of the display. This multi-functionality justifies their inclusion without proportionally increasing complexity.
3Ease of manufacture
If the light emitting direction of LED is made uniform across all regions, then manufacturing simplicity is improved, but brightness uniformity deteriorates due to cumulative light effects
Solution Approach 1:
The patent applies preliminary anti-action by pre-positioning light shielding members to counteract the cumulative light effects that would otherwise cause brightness non-uniformity. This allows uniform LED orientation to be maintained while preventing the anticipated brightness problems.
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 effectively reduces uneven brightness across the display surface, ensuring uniform illumination and improved image quality by aligning the optical axis of LEDs with the light guide plate and using dimming patterns that reflect and transmit light to minimize intensity variations.
Implementation Method 1
the light incoming from the light source travels inside the light guide plate by total internal reflection or the like
Implementation Method 2
is scattered by a diffusion/light guide pattern provided on the surface of the light guide plate, and is extracted from the surface of the light guide plate
Data Source
AI summary
An illumination unit includes an LED and a tabular light guide plate having a light emitting surface for emitting light from the LED as planar light, wherein a recessed portion is formed in the opposite surface of the tight emitting surface of the light guide plate, and wherein the LED is provided in the recessed portion so that the optical axis of the LED becomes parallel to the light emitting surface of the light guide plate. Further, a plurality of LEDs are arranged along the longer direction of the recessed portion, a dimming pattern is provided at a location corresponding to each of a plurality of LED of the light emitting surface of the light guide plate, and the shape or the size of the dimming pattern is varied with a location on the light emitting surface of the light guide plate.