Optical Sheet Foot Fixing Backlight Noise Reduction
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Solution Overview
Problem
Liquid crystal display devices with edge-lit backlight assemblies experience noise due to movement of optical sheets when shaken, as they lack a fixing structure, leading to interference and wrinkles during high-temperature reliability tests.
Innovation Solution
A liquid crystal display device with a modified structure featuring a top sheet with a foot that extends over the light guide plate and is half-fixed between light emitting elements and the bottom cover, creating a guide slot for the foot to be inserted, thereby minimizing sheet movement and preventing wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If optical sheets are not fixed in the backlight assembly, then assembly is simple and manufacturing is easy, but the sheets move when the device is shaken causing noise and interference
Solution Approach 1:
The optical sheet is divided into a body portion and a separate foot portion. The foot extends from the body and is inserted into a groove on the light guide plate, creating a modular fixing structure that prevents sheet movement while maintaining assembly simplicity.
Solution Approach 2:
A groove structure on the light guide plate serves as an intermediary element between the optical sheet and the backlight assembly. The foot of the optical sheet fits into this groove, providing stable positioning without requiring complex fixing mechanisms.
2Reliability
If gaps are made between optical sheets and other components to prevent wrinkles, then wrinkle prevention is improved, but the device structure becomes more complex and assembly is more difficult
Solution Approach 1:
Instead of creating gaps in the horizontal plane, the solution extends the fixing structure vertically by adding a foot that protrudes downward from the optical sheet body. This foot inserts into a groove on the light guide plate, providing wrinkle prevention through vertical constraint rather than horizontal spacing.
Solution Approach 2:
The foot is pre-formed as an integrated part of the optical sheet during manufacturing. This preliminary formation of the fixing structure eliminates the need for separate assembly steps to create gaps or add fixing components, simplifying the overall assembly process while preventing wrinkles.
3Reliability
If a foot structure is added to the top sheet to fix it in place, then sheet movement is reduced and noise is minimized, but the manufacturing process becomes more complex
Solution Approach 1:
The foot is merged with the optical sheet as a single integrated component. This combining of the fixing structure with the functional sheet eliminates the need for separate fixing parts and simplifies the manufacturing process, as the foot can be formed during the same lamination or molding process as the optical sheet itself.
Data Source
AI summary
Described is a liquid crystal display device including an edge light source array or a direct-type light source array and a group of optical sheets disposed over a light guide plate. The liquid crystal display device has at least one foot that extends towards the side of the bottom cover from one edge of a top sheet among the group of optical sheets. The at least one foot partially fixes the group of optical sheets to prevent movement in the vertical and horizontal directions in an upright display orientation, while allowing for expansion of the optical sheets during manufacturing.