Light Bar Adhesive Tape for Backlight Hot Spot Elimination
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Solution Overview
Problem
The existing adhesive tapes for light bars in smartphones fail to effectively eliminate the phenomena of bright bands and hot spots on the incident light side of the backlight source, leading to reduced average brightness and suboptimal optical specifications, even when using black tapes or mesh in the light guide plate.
Innovation Solution
An adhesive tape with a black and white flexible coating layer, where the white coating particles have a larger radius than the black particles, is used to create a seamless contact with the light guide plate, reducing non-effective light luminance and maintaining the luminous efficiency of the LED, thereby eliminating bright bands and hot spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a black adhesive tape of rectangular ring shape is used, then the bright band and hot spot phenomena are reduced, but the average brightness is reduced by about 10%
Solution Approach 1:
The patent applies local quality by using different colored adhesive tapes (black and white) in different spatial locations. The black adhesive tape is positioned at the incident light side to absorb stray light and eliminate bright bands, while the white adhesive tape is positioned at the opposite side to maintain light reflection and preserve average brightness. This spatial differentiation of material properties resolves the contradiction between eliminating harmful optical phenomena and maintaining overall illumination.
Solution Approach 2:
The patent employs composite materials by combining black and white adhesive tapes with different optical properties into a single adhesive tape assembly. The black portion provides light absorption to eliminate bright bands, while the white portion provides light reflection to maintain brightness, creating a composite solution that simultaneously addresses both contradictory requirements.
2Reliability
If press is applied on the incident light side, then assembly is secured, but average brightness is further reduced by 3% to 5%
Solution Approach 1:
The patent applies local quality by positioning the black adhesive tape specifically at the incident light side where pressing occurs. This localized placement ensures that the pressing force is absorbed by the black tape material without transmitting excessive pressure to the LED light source, thereby securing the assembly while minimizing brightness reduction.
3Illumination intensity
If mesh in light guide plate and V-CUT are used, then light distribution is improved, but bright band on incident light side cannot be notably improved
Solution Approach 1:
The patent introduces an intermediary element - the black adhesive tape - positioned between the incident light source and the light guide plate. This intermediary absorbs stray light and prevents it from creating bright bands, complementing the light distribution improvements achieved by mesh and V-CUT structures without interfering with their function.
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 adhesive tape achieves a seamless contact with the light guide plate, reducing non-effective light luminance and maintaining the LED's luminous efficiency, ensuring stable overall light brightness and eliminating bright bands and hot spots on the incident light side.
Implementation Method 1
the radius of the white coating particle is twice of that of the black coating particle... increases the emergent angle on the incident light side of the backlight source and achieves an increasing atomization effect
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The present disclosure relates to a light bar adhesive tape for a backlight source, including: a transparent bonding material layer (110) configured to be bonded to a surface of a light bar flexible circuit board; a black and white flexible coating layer (120)having a black surface on one side and a white surface on the other side, the white surface (120w) of the black and white flexible coating layer (120) being bonded with the transparent bonding material layer (110); and a black and white bonding material layer (130)having a black surface on one side and a white surface on the other side, the black surface (130B) of the black and white bonding material layer (130) being bonded with the black surface (120B) of the black and white flexible coating layer (120). The present disclosure also relates to a backlight module including the light bar adhesive tape as above described and a display device including the backlight module. The phenomena of bright band and hot spot on the incident light side of the backlight source can be eliminated with the light bar adhesive tape of the present disclosure.