Backlight Module Reflective Sheet Design for Light Coupling
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Solution Overview
Problem
Current backlight modules in TFT-LCD displays face inefficiencies in light coupling due to temperature and humidity-induced expansion and compression issues with reflective sheets, leading to uneven brightness and reduced light guidance efficiency.
Innovation Solution
A backlight module design featuring a first reflective sheet at the bottom of the light guide plate and a second reflective sheet positioned under the light-emitting element, extending towards the backlight frame, with an elastic supporting member and accommodation recess to secure the second reflective sheet, ensuring light is effectively guided into the light guide plate without gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reflective sheet is bonded to the bottom of the light guide plate and extends to a lower location under the light-emitting element, then the light coupling efficiency increases, but temperature and humidity-induced expansion and compression are restricted, resulting in uneven brightness and wave-shape strips
Solution Approach 1:
The reflective sheet is divided into two separate components: a first reflective sheet bonded to the bottom of the light guide plate, and a second reflective sheet placed in a groove between the light guide plate and backlight frame. This segmentation allows each sheet to perform its specific function independently, preventing the uniform expansion/compression issues that cause wave-shape strips while maintaining effective light coupling.
Solution Approach 2:
A groove is introduced as an intermediary structure between the light guide plate and backlight frame to hold the second reflective sheet. This groove acts as a mediator that prevents direct bonding of the reflective sheet to the light guide plate bottom, allowing thermal expansion and compression to occur freely while still maintaining the reflective function.
2Reliability
If the reflective sheet is placed between the light guide plate and the backlight frame in a free state, then expansion and compression are allowed, but the reflective sheet may be retracted from the lower location under the light-emitting element, failing to enhance light guidance efficiency
Solution Approach 1:
The reflective system is segmented into two parts: the first reflective sheet bonded to the light guide plate bottom for stable light coupling, and the second reflective sheet placed in the groove for thermal accommodation. This segmentation ensures both functions are achieved simultaneously without interference.
Solution Approach 2:
The groove structure replicates the function of a bonded connection while avoiding its harmful effects. The groove holds the second reflective sheet in place without requiring direct bonding to the light guide plate, allowing thermal movement while maintaining positional stability for effective light guidance.
3Productivity
If the reflective sheet is extended to the bottom of the light-emitting element along the vertical direction, then the efficiency of incident light guided into the light guide plate increases, but the structure becomes more complex and prone to deformation
Solution Approach 1:
The extended reflective sheet function is divided between two separate sheets: the first sheet provides base reflection at the light guide plate bottom, while the second sheet in the groove extends further to capture additional light from the light-emitting element. This segmentation achieves extended coverage without creating a single complex deformation-prone structure.
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
Enhances light guidance efficiency by preventing gaps and ensuring consistent light distribution, reducing temperature and humidity-induced issues, and maintaining brightness levels.
Implementation Method 1
a reflective sheet is provided at the bottom of the light guide plate along the vertical direction... the efficiency of incident light guided into the light guide plate from the light-emitting element increases
Implementation Method 2
an elastic supporting member for buffering is provided between a lower location under the light guide plate along the vertical direction and an upper location above the bottom of the backlight frame along the vertical direction
Data Source
AI summary
The present disclosure relates to a backlight module, including a backlight frame and a light guide plate placed inside the backlight frame, wherein a light-emitting element is provided at the inner side of a side wall of the backlight frame, a first reflective sheet is provided at a lower location under the light guide plate along the vertical direction, and a second reflective sheet is provided at a lower location under the light-emitting element along the vertical direction, the second reflective sheet being extended towards the inside of the backlight frame to a lower location under the light guide plate along the vertical direction. Through providing the second reflective sheet located under the light-emitting element and extending to a lower location under the light guide plate, the light scattered out under the light-emitting element can be guided into the light guide plate, thus effectively enhancing the efficiency of incident light guided into the light guide plate from the light-emitting element.