Light Guide Plate Cutout Design for Backlight Brightness Uniformity
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Solution Overview
Problem
The presence of a cutout portion near the effective display region in liquid crystal display devices causes uneven brightness due to light leakage and reflection, affecting the brightness of the display area.
Innovation Solution
Incorporating a foreset concave portion with a shallower recess than the engaging concave portion, positioned in front of the cutout portion, to disperse light reflections and reduce the impact on the effective display region's brightness, along with an inclined surface to further disperse reflection positions and directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cutout portion is provided at the edge of the light guide plate to prevent shifting, then the light guide plate can be securely fixed, but light leakage and reflection occur near the effective display region causing uneven brightness
Solution Approach 1:
The cutout portion is divided into two functional areas: a first cutout area extending from the edge for fixation, and a second cutout area with reduced depth positioned between the first cutout area and the effective display region. This segmentation allows the light guide plate to be securely fixed while preventing light leakage into the display area, thus resolving the contradiction between fixation reliability and brightness uniformity.
Solution Approach 2:
The cutout portion has non-uniform depth characteristics: the first cutout area has a greater recess depth for secure fixation, while the second cutout area has a reduced recess depth to minimize light reflection. This local quality variation allows different portions of the same structure to serve different functions, solving both the fixation requirement and the brightness uniformity issue.
2Length of moving object
If the cutout portion is positioned close to the effective display region to maintain a narrow frame, then the frame width is reduced, but brightness unevenness increases due to light reflection at the cutout boundary
Solution Approach 1:
The cutout portion is segmented into a first cutout area for structural fixation and a second cutout area with reduced depth positioned between the first cutout area and the effective display region. This segmentation allows the frame to remain narrow while the second cutout area prevents light reflection from affecting the display region, thus resolving the contradiction between frame width and brightness uniformity.
Solution Approach 2:
The second cutout area acts as an intermediary zone between the first cutout area (fixation region) and the effective display region. This intermediate structure with reduced recess depth serves as a buffer that prevents direct light reflection from reaching the display area, allowing narrow frame design without compromising brightness uniformity.
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 enhances the uniformity of brightness by reducing the effect of the cutout portion on the display region, minimizing noticeable brightness variations.
Implementation Method 1
a light source for emitting illumination light so that the illumination light enters the light guide plate from a lateral surface of the light guide plate; a liquid crystal panel, which is arranged on a front side of the light guide plate and is irradiated with the illumination light guided by the light guide plate
Implementation Method 2
an inclined surface to further disperse reflection positions and directions
Data Source
AI summary
Provided is a liquid crystal display device in which uneven brightness in a side-light type backlight unit is reduced, the uneven brightness being generated through reflection of light from a light source at an interface of an engaging cutout portion for preventing a light guide plate from shifting. A light guide plate (60) includes a cutout portion (82) through which a light guide plate support pin (80) provided upright to a lower frame fitting is inserted, at a lower side adjacent to a left side at which a light bar (64) is arranged. Further, at the lower side, a cutout portion (84) having a shallower recess than that of the cutout portion (82) and positioned in front of the cutout portion (82) when viewed from the light bar (64) is provided.