Backlight Unit Guide Pin Reflectivity Brightness Uniformity
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Solution Overview
Problem
Conventional backlight units exhibit non-uniform brightness distribution due to differences in reflectivity between the reflective sheet and the fixing part, leading to dark lines and reduced brightness in certain regions.
Innovation Solution
The introduction of a guide pin with reflectivity matching the reflective sheet, which supports an optical sheet and positions the fixing part to ensure uniform light reflection, and the use of stepped or recessed portions on the reflective sheet to maintain a flat surface and enhance brightness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixing part with standard reflectivity (60-70%) is used to secure the reflective sheet and LED module, then the structural stability is improved, but the brightness uniformity deteriorates due to the reflectivity difference creating dark lines
Solution Approach 1:
The patent applies local quality by making the guide pin's reflective surface have the same reflectivity as the reflective sheet (98% or more), while other components maintain their standard reflectivity. This localized enhancement of reflectivity at the guide pin specifically addresses the brightness uniformity issue in the region where the fixing part is positioned, without requiring changes to the entire structure.
Solution Approach 2:
The guide pin acts as an intermediary component between the fixing part and the reflective sheet. It mediates the optical interaction by providing a highly reflective surface that matches the reflective sheet, thereby preventing the formation of dark lines while still allowing the fixing part to perform its structural function.
2Illumination intensity
If the guide pin is positioned to support the optical sheet and position the fixing part, then the brightness uniformity is improved through matched reflectivity, but the device complexity increases due to additional components and positioning requirements
Solution Approach 1:
The guide pin performs multiple functions: it supports the optical sheet, positions the fixing part, and provides a highly reflective surface to maintain brightness uniformity. By combining these functions into a single component, the patent reduces the need for separate elements and minimizes device complexity while achieving the desired optical performance.
Solution Approach 2:
The patent merges the structural support function and the optical reflection function into the guide pin. This consolidation eliminates the need for separate support structures and reflective elements, thereby simplifying the overall device design while maintaining brightness uniformity.
3Illumination intensity
If stepped or recessed portions are added to the reflective sheet to maintain a flat surface, then the brightness uniformity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The stepped or recessed portions are locally implemented only in the region corresponding to the guide pin, rather than modifying the entire reflective sheet. This localized approach minimizes the impact on manufacturing precision requirements while still achieving the desired flat surface effect and brightness uniformity in the critical region.
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 improves brightness uniformity across the backlight unit, ensuring consistent light distribution and high-quality image display in devices like liquid crystal display devices.
Implementation Method 1
The reflective sheet 140 reflects light emitted from the LED 113 in the upward direction
Implementation Method 2
The guide pin 150 has reflectivity substantially identical or similar to that of the reflective sheet 140
Data Source
Figure 1~4
Figure 5
AI summary
A backlight unit according to the embodiment comprises an LED module comprising an LED; a case supporting the LED module; a fixing part fixing the LED module to the case; a reflective sheet comprising an opening for exposing the LED on the LED module and the fixing part; and a guide pin fixing the reflective sheet to the case.