Reflective Sheet Support for Mini-LED Alignment Stability
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Solution Overview
Problem
In lighting devices with mini-LEDs, the reflective sheet easily expands and contracts, causing displacement of LED openings and potential short circuits due to contact with solder, and existing solutions either compromise luminance or are impractical due to the small size and tight spacing of LEDs.
Innovation Solution
A lighting device with a reflective sheet having metal film and supports of varying heights to prevent contact between the reflective sheet and solder, where the supports are formed on the reflective sheet or substrate to maintain proper alignment and prevent short circuits, and adhesive materials are used to secure the sheet without air bubbles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the reflective sheet is made thinner to reduce backlight thickness, then the overall device thickness is reduced, but the reflective sheet becomes more prone to expansion and contraction under heat, causing displacement of LED openings from LED positions
Solution Approach 1:
The reflective sheet is segmented into multiple regions: a first reflective region with first LED openings for mini-LEDs, and a second reflective region with second LED openings for conventional LEDs. This segmentation allows each region to be optimized independently for its specific LED type, with the first region having smaller openings arranged in a matrix pattern suitable for mini-LEDs while the second region having larger openings for conventional LEDs
Solution Approach 2:
Different regions of the reflective sheet are assigned different local qualities - the first reflective region has smaller LED openings optimized for mini-LEDs with tight pitches, while the second reflective region has larger LED openings optimized for conventional LEDs. This local differentiation allows each region to maintain proper alignment with its corresponding LEDs despite thermal expansion variations
2Manufacturing precision
If the LED openings are made smaller to accommodate mini-LEDs with narrow pitches, then mini-LEDs can be properly positioned, but the reflective area decreases, leading to reduced luminance
Solution Approach 1:
The reflective sheet is divided into a first reflective region with small LED openings for mini-LEDs and a second reflective region with larger LED openings for conventional LEDs. This segmentation ensures that each region optimizes the reflective area for its specific LED type, maintaining high luminance while accommodating the precise positioning requirements of mini-LEDs
Solution Approach 2:
The reflective sheet functions as a composite structure with two distinct reflective regions having different opening characteristics. The first reflective region uses smaller openings optimized for mini-LEDs while the second reflective region uses larger openings for conventional LEDs, creating a composite reflective surface that optimizes both precision and luminance for different LED types
3Reliability
If a fixing member is used to attach the reflective sheet to the LED substrate, then alignment stability is improved, but the device complexity increases and space is consumed that is needed for mini-LEDs with narrow pitches
Solution Approach 1:
The reflective sheet is designed to be directly attached to the LED substrate without a separate fixing member. The attachment is achieved by bonding the reflective sheet to the LED substrate, integrating the reflective sheet and substrate into a single assembled unit. This merging eliminates the need for additional fixing components, reducing device complexity and freeing up space for mini-LEDs with narrow pitches while maintaining alignment stability through the direct bond
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
Prevents short circuits and maintains luminance by ensuring the reflective sheet does not contact solder, even with thermal expansion, and allows for secure bonding without damaging the LEDs.
Implementation Method 1
a reflective sheet having a plurality of LED openings in which the plurality of LEDs are disposed, respectively, and having a metal film on a surface of the reflective sheet opposite to a surface of the reflective sheet that faces the LED substrate
Data Source
AI summary
[Object] To provide a lighting device and a display device that can prevent contact between a reflective sheet having a metal film and solder firmly fixed to terminal areas of LEDs that are disposed in LED openings of the reflective sheet.[Solution] A lighting device 10 includes: a plurality of LEDs 15 serving as backlight light sources; an LED substrate 11 mounted with the plurality of LEDs 15; a reflective sheet 12 having a plurality of LED openings 13 in which the plurality of LEDs 15 are disposed, respectively, and having a metal film on a surface of the reflective sheet 12 opposite to a surface of the reflective sheet 12 that faces the LED substrate 11; and a support 17 that supports the reflective sheet 12 at a higher position than a height of solder 16 firmly fixed to terminal areas of the LEDs 15 that face the LED substrate 11.