Planar Lighting Device Adhesive Fixing Member
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Solution Overview
Problem
Conventional sidelight planar lighting devices face challenges in reliably and stably fixing flexible printed circuit boards (FPCs) to light guide plates due to insufficient bonding strength of small double-sided tape pieces, especially when exposed to high temperatures and varying materials, leading to reduced workability and yield.
Innovation Solution
A two-layer fixing member is introduced, comprising a single-sided adhesive member and integrated small-piece double-sided adhesive members, which provides a larger adhesive area and allows for separate arrangement, enhancing bonding strength and optical characteristics while preventing light interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If small pieces of double-sided tape are disposed independently and intermittently, then the adhesive area is reduced to match LED spacing, but the bonding strength to FPC becomes insufficient
Solution Approach 1:
The adhesive member is segmented into multiple small-piece double-sided adhesive members disposed intermittently along the light incident surface, with gaps between them matching the LED spacing to prevent light interference while maintaining sufficient bonding strength
Solution Approach 2:
Multiple small-piece double-sided adhesive members are integrated by a single-sided adhesive member that bonds them together to form a unified fixing member, providing both sufficient adhesive area and bonding strength
2Temperature
If the FPC is exposed to high temperature to mount LEDs, then the LEDs can be properly mounted, but the process of fixing the double-sided tape becomes more difficult
Solution Approach 1:
The small-piece double-sided adhesive members are pre-integrated onto the single-sided adhesive member before the FPC is exposed to high temperature for LED mounting, ensuring the adhesive is already in position and reducing manual handling after thermal processing
3Illumination intensity
If the number of LEDs is increased to achieve higher luminance, then the luminance increases, but the pitch between LEDs becomes narrower making fixation more difficult
Solution Approach 1:
The adhesive member is segmented into multiple small pieces spaced to match the narrow LED pitch, with each small-piece adhesive member positioned in gaps between adjacent LEDs to provide fixation without interfering with light emission
Solution Approach 2:
The adhesive members are selectively disposed only in the gaps between adjacent LEDs along the light incident surface, providing localized fixation precisely where needed while maintaining narrow LED pitch for high luminance
4Adaptability or versatility
If small pieces of double-sided tape are used, then the adhesive can be arranged in separated positions, but the pieces may peel off the FPC when the release liner is removed
Solution Approach 1:
Multiple small-piece double-sided adhesive members are merged into a unified structure by bonding them to a single-sided adhesive member, which provides sufficient adhesive area to prevent peeling when the release liner is removed while maintaining the separated arrangement configuration
Solution Approach 2:
The fixing member is constructed as a composite structure combining double-sided adhesive members for light-gap positioning with a single-sided adhesive member for stable bonding to the FPC, achieving both arrangement flexibility and fixation reliability
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 stabilizes the fixation of FPCs to light guide plates, increases luminance by optimizing the arrangement of adhesive members, and improves manufacturing efficiency by allowing pre-production of the fixing member and easier application, reducing the risk of peeling and enhancing structural strength.
Implementation Method 1
a single-sided adhesive member that integrates the plurality of small-piece double-sided adhesive members
Implementation Method 2
small-piece double-sided adhesive members... that fixes the circuit board to the light guide plate
Data Source
AI summary
A planar lighting device includes: a plurality of point light sources; a circuit board provided with the point light sources; a light guide plate including an end surface along which the point light sources are disposed in a facing manner and a surface to which a portion of a front end of the circuit board is fixed; and a fixing member that fixes the circuit board to the light guide plate. The fixing member includes: a plurality of small-piece double-sided adhesive members; and a single-sided adhesive member that integrates the plurality of small-piece double-sided adhesive members.