Compression Molded Light Guide Plate Burr Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing spread illuminating apparatuses for liquid crystal display devices face issues with dimensional accuracy and assemblability due to burrs formed during the injection compression molding process, leading to defects such as optical sheets riding up and insufficient adherence of light blocking members, which become more pronounced with further thickness reductions.
Innovation Solution
The apparatus incorporates a light guide plate with protruding and recessed parts on its surfaces to determine the thickness accurately, reducing the occurrence of burrs and ensuring proper alignment and adherence of optical sheets and light blocking members, while also reducing light leakage and enhancing light emission uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the light guide plate thickness is reduced to meet the thinness requirement, then the overall apparatus thickness is reduced, but burrs formed during injection compression molding become a more significant factor leading to dimensional inaccuracies and assembly defects
Solution Approach 1:
The patent converts the harmful burr formation during injection compression molding into a beneficial feature by deliberately designing protruding parts on the light guide plate that utilize the burr material. The burrs are redirected to form functional protrusions that engage with corresponding recesses in the frame, creating positive positioning features that improve assembly precision rather than causing defects
Solution Approach 2:
The patent changes the parameters of the injection compression molding process to control burr formation and location. By adjusting molding pressure, temperature, and cavity design, the burrs are consistently formed in specific locations and quantities that match the designed protruding parts, transforming an unpredictable defect into a controlled manufacturing feature
2Area of stationary object
If the frame edge is narrowed to reduce the apparatus size, then the overall dimensions are reduced, but the adherence of light blocking members becomes insufficient due to reduced contact area
Solution Approach 1:
The patent transitions from relying solely on the two-dimensional contact area between the light blocking member and frame to a three-dimensional mechanical interlocking system. Protruding parts on the light guide plate engage with recesses in the frame, creating vertical engagement that supplements the horizontal adhesive bonding, thereby maintaining reliability even with reduced frame edge width
Solution Approach 2:
The patent segments the adherence function into multiple mechanisms: adhesive bonding between the light blocking member and frame surface, and mechanical interlocking through protruding-recess engagements. This segmentation allows the system to maintain overall adherence strength even when the adhesive contact area is reduced due to narrower frame edges
3Illumination intensity
If optical sheets are stacked on the light guide plate to improve light diffusion, then light emission uniformity is enhanced, but the sheets may ride up on burrs causing assembly defects
Solution Approach 1:
The patent converts the harmful burrs into beneficial protruding parts that serve as positioning features. These controlled protrusions engage with corresponding recesses in the frame to create a mechanical stop that prevents optical sheets from riding up during assembly, transforming the original defect into an anti-rider mechanism
Solution Approach 2:
The protruding parts and recesses act as intermediary mechanical features between the light guide plate and the optical sheets/frame assembly. This intermediary mechanism provides positive positioning and prevents misalignment or riding up of the optical sheets, ensuring reliable assembly without requiring additional adhesives or complex fixing mechanisms
Data Source
AI summary
The illumination apparatus includes a light guide plate, a light source disposed opposing an incident light surface of the light guide plate, at least one optical sheet stacked on a light emitting surface of the light guide plate, and a frame for accommodating the light guide plate. On principal surfaces of the light guide plate, a protruding part and a recessed part are provided so as to form a pair at least along an end surface of the light guide plate extending in a direction that intersects an end surface serving as the incident light surface of the light guide plate, or along an end surface that opposes the incident light surface of the light guide plate.