Zigzag Optical Sheet Extending Portion Thermal Bending
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Solution Overview
Problem
Current liquid crystal display devices face issues with thermal expansion of the optical sheet causing bending and allowing foreign substances to enter the gap between the optical sheet and the liquid crystal panel, leading to light unevenness and image degradation.
Innovation Solution
A lighting device with an optical sheet featuring a folded zigzag extending portion that covers the clearance space between the optical sheet and the housing member, preventing foreign substances from entering and suppressing thermal bending by retracting during temperature increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clearance space is ensured between the optical sheet and the frame to prevent thermal expansion bending, then light unevenness is avoided, but foreign substances can enter the clearance space and move to the active area causing image degradation
Solution Approach 1:
The optical sheet is divided into a body portion and an extending portion with zigzag folds. The extending portion acts as a separate segment that can be folded to cover the clearance space, preventing foreign substance entry while allowing the body portion to expand thermally without bending.
Solution Approach 2:
The extending portion of the optical sheet is designed as a flexible zigzag structure that can fold and unfold. This flexible thin film structure covers the clearance space to prevent foreign substance entry, while its folding capability allows it to accommodate thermal expansion of the optical sheet body portion.
2Shape
If the optical sheet is made rigid to maintain planarity, then light distribution is improved, but thermal expansion causes bending and contact with the frame
Solution Approach 1:
The optical sheet incorporates a zigzag-folded extending portion that can dynamically fold and unfold in response to thermal expansion. This dynamic structure allows the optical sheet to maintain planarity during operation while accommodating temperature-induced expansion through the folding mechanism.
Solution Approach 2:
The extending portion is designed with zigzag folds creating curved paths. This curved geometry allows the extending portion to compress and expand in a controlled manner during thermal cycles, preventing the main body of the optical sheet from bending while still covering the clearance space.
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 effectively prevents foreign substances from entering the active area of the liquid crystal panel, maintaining image quality and ensuring the optical sheet remains planar during thermal expansion.
Implementation Method 1
Since the optical sheet expands thermally along its plate face as operation temperature rises. Accordingly, an expanded front end of the optical sheet contacts a frame and the like to bend the plate face
Implementation Method 2
The extending portion is folded in a zigzag manner, and is arranged in such a manner as to cover a region between the outer peripheral edge of the optical member and the housing member
Data Source
AI summary
A lighting device for applying light to an irradiation object includes a light source, an optical member, an optical sheet, and a housing member. The optical member is in a plate shape through which light from the light source enters. The optical sheet is configured to apply optical action to the light exiting from the optical member. The optical sheet includes a plate body portion and an extending portion provided on at least a first end of the body portion. The extending portion is folded in a zigzag manner and arranged in such a manner as to cover a region between the outer peripheral edge of the optical member and the housing member. The housing member is configured to surround an outer peripheral edge of the optical member and an outer peripheral edge of the optical sheet.