Backlight Module Reflector Design for LCD Hot Spot Reduction
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Solution Overview
Problem
Conventional edge-type backlight modules for LCDs face issues with hot spots due to an overly low A/P ratio, which is exacerbated by the requirement for slim border designs, leading to increased manufacturing costs when attempting to uniformize luminance.
Innovation Solution
Incorporating a reflector with first and second reflection parts in the backlight module, where the second reflection parts extend further into the effective illumination region, improving light distribution intensity between LED devices and reducing hot spots without significantly increasing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the distance A from LED devices to the edge of the effective illumination region is shortened to meet slim border design requirements, then the border size is reduced, but hot spots are generated in the effective illumination region
Solution Approach 1:
The reflector is designed with different extension lengths for different regions: first reflection parts extend from beneath individual LED devices, while second reflection parts extend further between adjacent LEDs. This local differentiation in reflection structure creates targeted light redistribution that compensates for the non-uniform luminance distribution caused by shortened distance A, thereby maintaining luminance uniformity while enabling slim border design.
Solution Approach 2:
The reflector acts as an intermediary optical element between the LED devices and the light guide plate. It intercepts light emitted by LEDs and redirects it through the light guide plate to fill dark regions and reduce hot spots, effectively mediating the light distribution to achieve uniform luminance even when distance A is shortened for slim border requirements.
2Manufacturing precision
If the pitch P between adjacent LED devices is shortened to remove hot spots, then luminance uniformity is improved, but the number of LED devices required increases, leading to increased manufacturing costs
Solution Approach 1:
Instead of uniformly reducing pitch P across the entire light bar, the invention applies localized reflection structures: first reflection parts beneath each LED and second reflection parts between adjacent LEDs. This local quality approach allows maintenance of larger pitch P (reducing LED quantity) while still achieving luminance uniformity through targeted light redistribution via the reflector.
Solution Approach 2:
The reflector serves as an intermediary that enables luminance uniformity without requiring reduced pitch. By introducing this optical mediator, the system achieves uniform light distribution through reflection and redirection, eliminating the need to increase LED density and thereby avoiding increased manufacturing costs.
3Length of moving object
If the A/P ratio is reduced to meet slim border design, then the border size is minimized, but dark and bright hot spots are generated requiring more LED devices which increases cost
Solution Approach 1:
The reflector implements local quality by providing different extension lengths in different regions: first reflection parts extend a certain length beneath individual LEDs, while second reflection parts extend further between adjacent LEDs. This localized structural differentiation enables the system to maintain larger pitch P and higher A/P ratio (reducing LED count and cost) while still achieving uniform luminance and eliminating hot spots through targeted light redistribution.
Solution Approach 2:
The reflector acts as an intermediary optical component that enables the system to achieve both slim border design (small distance A) and cost-effectiveness (fewer LEDs). By mediating light distribution through reflection and redirection, it eliminates hot spots without requiring increased LED density, thereby maintaining ease of manufacture and lower manufacturing costs.
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
The solution effectively removes hot spots by enhancing light distribution between LED devices, allowing for a shorter distance between LED devices and the edge of the illumination region, meeting slim border design requirements without substantial cost increases.
Implementation Method 1
The reflector includes a plurality of first reflection parts corresponding to the solid-state light-emitting devices and a plurality of second reflection parts
Data Source
AI summary
A backlight module includes an LGP and a linear light source. The LGP includes a light-incident side surface and a top light-emitting surface that has a peripheral region and an effective illumination region. The linear light source includes a circuit board, solid-state light-emitting devices configured on and electrically connected to the circuit board, and a reflector covering a portion of the peripheral region. Light emitted from each solid-state light-emitting device enters the LGP from the light-incident side surface. The reflector includes first reflection parts that correspond to the solid-state light-emitting devices and second reflection parts. Each second reflection part is connected to two adjacent first reflection parts. Each first reflection part and each second reflection part extend towards the effective illumination region from an edge of the top light-emitting surface. An extension length of each first reflection part is shorter than that of each second reflection part.