Edge-Lit Backlight Light Guide Plate Thermal Expansion Support
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Solution Overview
Problem
Existing edge-lighting type backlight devices for liquid crystal display devices face issues with light guide plate thermal expansion and contraction, leading to changes in the distance between the light source and the light-receiving face, which can result in reduced light incidence efficiency and uneven brightness.
Innovation Solution
The illumination device incorporates a light guide plate with a supporting member that has an inclined portion, allowing the light guide plate to thermally expand or contract while maintaining a stable distance between the light source and the light-receiving face, preventing interference and blocking of light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light guide plate is bonded to the inner frame member to hold it in position, then the light guide plate is supported, but the light guide plate cannot accommodate thermal expansion and contraction, causing the light-receiving face to shift toward the light source and reducing light incidence efficiency
Solution Approach 1:
The support structure transitions from a rigid fixed bonding configuration to a dynamic configuration that allows controlled movement. The light guide plate is supported at corner areas while permitting thermal expansion and contraction, enabling the structure to adapt to temperature changes without compromising light incidence efficiency
Solution Approach 2:
The invention changes the physical state and positional parameters of the light guide plate during thermal cycles. By allowing controlled positional changes at the supported corner areas, the system accommodates thermal expansion and contraction while maintaining optimal light-receiving face positioning relative to the light source
2Stability of the object's composition
If the light guide plate is rigidly fixed to prevent movement, then positioning stability is improved, but thermal expansion causes the light guide plate to interfere with or damage the light source
Solution Approach 1:
The support structure is designed with predetermined clearance and flexible support characteristics at the corner areas, providing a cushioning effect before thermal expansion can cause harmful interference. This allows the light guide plate to expand and contract without transmitting damaging forces to the light source
Solution Approach 2:
The rigid fixed bonding is replaced with a dynamic support system that maintains positioning stability while accommodating thermal movements. The light guide plate remains stably positioned during operation but can move freely during thermal expansion and contraction cycles, preventing light source damage
3Ease of manufacture
If bonding is used to hold the light guide plate, then assembly is simplified, but the light guide plate cannot adjust its position during thermal cycles, leading to uneven brightness
Solution Approach 1:
The static bonded configuration is replaced with a dynamic support arrangement at corner areas that maintains assembly simplicity while enabling thermal adaptation. The light guide plate can adjust its position during thermal cycles, ensuring uniform light distribution and preventing uneven brightness
Solution Approach 2:
Instead of uniformly bonding the entire light guide plate, the invention applies localized support only at corner areas. This local quality approach maintains ease of manufacture while allowing the majority of the light guide plate surface to move freely during thermal expansion and contraction, ensuring uniform light emission
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
This configuration stabilizes the light incidence efficiency and prevents uneven brightness, ensuring reliable operation and a narrower frame design for the backlight device.
Implementation Method 1
If the temperature inside the illumination device increases due to the light source turning ON, then the light guide plate thermally expands respectively in the first direction and the second direction
Implementation Method 2
If the temperature in the illumination device decreases, then the light guide plate thermally contracts, and therefore contracts in the first direction and the second direction
Data Source
AI summary
A backlight device is provided with the following: LEDs; a light guide plate formed in a rectangular plate shape and having at the end surfaces thereof a light-receiving face opposing the LEDs and a reflection surface disposed on the side opposite the light-receiving face, and having on the plate surface thereof a light-emitting surface that emits light; a portion to be supported provided to the corner part, from among the corner parts of the light guide plate, that is disposed on the opposite surface side; a supporting portion that supports the light guide plate in a first direction and a second direction by coming into contact with the portion to be supported, when the first direction is a direction in which the LEDs and the light guide plate are lined up, and the second direction is a direction that is orthogonal to the first direction and that follows along the light-emitting surface of the light guide plate; and a inclined portion that is provided to the portion to be supported and that forms a slanted shape with respect to both the first direction and the second direction, and by facing outward in the second direction is distanced from the LEDs in the first direction.