Injection Mold Gate Design for Light Guide Plate Uniformity
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Solution Overview
Problem
The existing injection molding process for light guide plates in LCDs results in residual stresses due to resin-filling imbalances and differential cooling rates, leading to deformation and defects such as the ripple phenomenon and white spots in LCD screens.
Innovation Solution
An injection mold with a modified gate portion design, where the width of the first end portion connected to the forming portion is 50%-80% of the forming portion's width, allowing for more even resin flow and reduced pressure, thereby minimizing residual stresses and improving light guide plate uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional injection mold is used for light guide plate fabrication, then the manufacturing process is simple, but residual stresses and deformation occur due to resin-filling imbalance and differential cooling
Solution Approach 1:
The injection mold is divided into multiple blocks (first block, second block, third block) with independent cooling channels. This segmentation allows differential cooling control for different regions of the light guide plate, reducing residual stresses and deformation while maintaining manufacturing precision.
Solution Approach 2:
Different regions of the mold are assigned different cooling rates through separate cooling channels in each block. The gate portion and forming portion have different cooling characteristics to control resin flow and minimize residual stresses, achieving local optimization of the molding process.
2Stability of the object's composition
If the gate portion width is reduced to control resin flow, then resin-filling imbalance is reduced, but the pressure on the light guide plate increases causing deformation
Solution Approach 1:
The gate portion width is specifically designed as 50%-80% of the forming portion width, optimizing the geometric parameter to balance resin flow control with pressure management. This parameter optimization prevents both resin-filling imbalance and excessive pressure-induced deformation.
3Length of moving object
If the light guide plate is made thinner to meet device requirements, then the LCD can be made smaller and lighter, but residual stresses cause deformation and picture quality defects
Solution Approach 1:
The mold design incorporates preliminary cooling channels and optimized gate portions that prevent residual stress generation during the molding process itself. By addressing the stress issue during fabrication rather than after, thin light guide plates can be produced without deformation or picture quality defects.
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 modified injection mold reduces residual stresses and deformation in light guide plates, enhancing the uniformity of the optical pattern and extending the lifetime of the light guide plate, preventing picture quality defects like the ripple phenomenon and white spots.
Implementation Method 1
a gate portion configured to guide the injected resin from the injection portion to the forming portion
Implementation Method 2
cooling the injected resin to form a molded light guide plate
Data Source
AI summary
An injection mold for forming a light guide plate including a first block, a second block configured to face the first block, a forming portion included between the first and second blocks facing each other and having a shape of the light guide plate, an injection portion formed at the first block and configured to receive injected resin for forming the light guide plate, and a gate portion configured to guide the injected resin from the injection portion to the forming portion. Further, a width of a first end portion of the gate portion that is connected to the forming portion is 50%-80% of a width of the forming portion.