Backlight Unit Light Guide Plate Wedge Groove Design
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Solution Overview
Problem
The light leakage phenomenon in LCD devices with wedge-type light guide plates causes uneven brightness, deteriorating picture quality by making adjacent image display areas brighter than the rest, which is not effectively addressed by existing technologies.
Innovation Solution
A backlight unit with a light guide plate featuring a first thicker portion, a second thinner portion, and a wedge portion, along with a flexible printed circuit board that covers the wedge portion and includes a groove opposite the boundary area between the first and second portions, preventing light leakage by suppressing the elastic strength of the circuit board and ensuring proper contact with the light guide plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a wedge-type light guide plate is used to reduce thickness, then the overall device thickness is reduced, but light leakage occurs at the wedge portion causing uneven brightness
Solution Approach 1:
A groove is introduced as an intermediary structure between the light guide plate and the flexible printed circuit board. This groove acts as a mediator that prevents direct contact between the light guide plate's wedge portion and the circuit board, thereby eliminating the light leakage path while maintaining the thin profile of the device.
Solution Approach 2:
The contact interface between the light guide plate and the flexible printed circuit board is segmented by introducing a groove. This segmentation separates the light guide function from the circuit board support function, preventing light from leaking through the wedge portion while maintaining structural integrity.
2Stability of the object's composition
If the flexible printed circuit board is extended to cover the wedge portion, then structural support is improved, but the board may lift off causing brightness variations
Solution Approach 1:
The groove serves as an intermediary that controls the contact between the flexible printed circuit board and the light guide plate. By preventing direct contact at the wedge portion, it eliminates the lifting off phenomenon that causes brightness variations, while the board still extends to provide structural support.
3Volume of moving object
If the light guide plate is made thinner at the wedge portion, then device slimness is achieved, but light leakage causes adjacent display areas to become brighter
Solution Approach 1:
The groove introduces an intermediary air gap between the light guide plate and the flexible printed circuit board at the wedge portion. This intermediary structure prevents light from leaking through the thin portion, maintaining uniform display brightness while preserving the slim design.
Data Source
AI summary
A backlight unit capable of preventing a light leakage phenomenon caused by using a light guide plate of wedge type is disclosed. The backlight unit includes: at least one light source; a light guide plate configured to include a first portion with a first thickness disposed adjacent to the at least one light source, a second portion of plate shape having a second thickness thinner than the first thickness, and a wedge portion formed to connect the first and second portions and become gradually thinner from the first portion to the second portion; and a flexible printed circuit board loaded with the at least one light source and extended to cover the wedge portion of the light guide plate. The flexible printed circuit board is provided with a groove formed opposite a boundary area between the first portion and the wedge portion.