Backlight Module Shading Layer Warping Prevention
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Solution Overview
Problem
Current mobile phone modules face warping issues with diffusers during reliability verification, particularly due to differences in thermal expansion coefficients, which complicates mass production.
Innovation Solution
A backlight module design featuring a shading layer with a middle portion and side portions, where the middle portion is not integrated with the diffuser, allowing for differential expansion and contraction without warping, using a black polyethylene terephthalate (PET) layer and a separation gap to prevent light interference and hotspot formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the diffuser is integrated with the shading layer, then the structure is simplified, but warping occurs after reliability verification due to differential thermal expansion
Solution Approach 1:
The shading layer is divided into a middle portion and side portions that are separated from each other. The side portions are fixed to the diffuser while the middle portion remains unfixed, allowing differential thermal expansion between materials without causing warping of the integrated structure.
2Stability of the object's composition
If the middle portion of the shading layer is fixed to the diffuser, then structural stability is improved, but thermal expansion differences cause warping
Solution Approach 1:
Different portions of the shading layer have different fixation states: the side portions are fixed to provide local structural stability, while the middle portion is unfixed to accommodate thermal expansion differences, thus resolving the contradiction between overall stability and warping resistance.
3Reliability
If extra components are added to prevent warping, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The shading layer structure itself provides the warping prevention function through its segmented design. The side portions fixed to the diffuser and the unfixed middle portion work together to accommodate thermal expansion, eliminating the need for additional warping prevention components.
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 prevents warping of the diffuser and shading layer by allowing for relative movement due to differing thermal expansion coefficients, maintaining the original manufacturing process and cost structure without adding extra components.
Implementation Method 1
a reflecting plate arranged on the reflective surface of the LGP to reflect transmitted light rays by the LGP to the emergent surface of the LGP
Implementation Method 2
a diffuser arranged on the emergent surface of the LGP to diffuse emergent light of the LGP
Implementation Method 3
a separation gap is arranged between the middle portion and the side portions
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A backlight module (100), comprising: a light guide plate (120) which comprises a light incident surface, a light exit surface, and a reflective surface; a reflective plate (110), which is disposed on the reflective surface of the light guide plate (120) and which is used for reflecting a transmitted light in the light guide plate (120) to the light exit surface; a diffusion sheet (130), which is disposed on the light exit surface of the light guide plate (120) and which is used for diffusing a light which is emitted from the light guide plate (120); a prism sheet group (140), which is disposed on a light exit surface of the diffusion sheet (130); a square sealant layer (150), which is disposed around the light exit surface of the light guide plate (120); a light source (170), which is disposed at a light incident surface side of the light guide plate (120); a light shielding layer (160), which is disposed between the diffusion sheet (130) and the square sealant layer (150) and which is disposed at an outer side of the prism sheet group (140), the light shielding layer (160) being disposed in correspondence with a light-incident side of the diffusion sheet (130); the light shielding layer (160) comprises an intermediate section (161) and a lateral section (162) which are separated, the length of the intermediate section (161) being greater than the length of the lateral section (162); two sides of the lateral section (162) are fixedly connected to the diffusion sheet (130) and the square sealant layer (150) respectively, while only one side of the intermediate section (161) is fixedly connected to the square sealant layer (150).