Curved Backlight Light Guide Plate Brightness Uniformity
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Solution Overview
Problem
Backlight units for liquid crystal displays with curved panels often experience brightness unevenness due to concentrated light output, leading to local bright spots.
Innovation Solution
A lighting unit with a light guide plate, light collecting pieces, and a total reflection regulator on the curved end surface to control light reflection, reducing the amount of light exiting in directions that cause brightness unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a curved light output area is used to match the curved outer shape of the liquid crystal panel, then the appearance is improved, but local bright portions are generated due to concentrated outgoing light
Solution Approach 1:
The patent applies different properties to different regions of the light guide plate. Specifically, the light guide plate has a curved light output area at the edges to match the curved panel shape, while the center area maintains a different configuration. Additionally, light collecting pieces are selectively positioned in certain regions but not others, creating local variations in light extraction properties that prevent concentrated brightness in specific areas while maintaining the overall curved appearance.
Solution Approach 2:
The light guide plate is divided into multiple functional regions: a curved light output area at the edges and a different configuration in the center. Light collecting pieces are also segmented and positioned at specific locations rather than uniformly distributed. This segmentation allows different regions to serve different purposes - the curved edges provide the desired appearance while the segmented light collecting pieces control light extraction to prevent local bright spots.
2Illumination intensity
If light collecting pieces are added to control light extraction, then light distribution is improved, but device complexity increases
Solution Approach 1:
The light collecting pieces are integrated directly into the light guide plate structure rather than being separate components. The pieces are formed as part of the light guide plate's bottom surface, combining the light guiding function with the light collecting function in a single integrated component. This merging reduces the number of separate parts and simplifies the overall device structure while still achieving improved light distribution.
Solution Approach 2:
The light collecting pieces modify the physical parameters of the light guide plate surface by creating specific geometric features (protrusions or recesses) with particular shapes, sizes, and distributions. By changing the surface parameters of the light guide plate in this way, the light extraction characteristics are controlled to achieve uniform distribution without requiring complex additional components.
3Shape
If the opposite end portion has a curved edge, then the appearance matches the curved panel, but light concentrates in the orthogonal direction causing local bright portions
Solution Approach 1:
The patent applies different properties to different regions of the light guide plate. Specifically, the light guide plate has a curved light output area at the edges to match the curved panel shape, while the center area maintains a different configuration. Additionally, light collecting pieces are selectively positioned in certain regions but not others, creating local variations in light extraction properties that prevent concentrated brightness in specific areas while maintaining the overall curved appearance.
Solution Approach 2:
The light collecting pieces act as an intermediary element between the curved end surface and the light exiting surface. These pieces intercept and redirect the light that would otherwise concentrate in the orthogonal direction from the curved end surface. By introducing this intermediary structure, the patent transforms the light path and distribution, preventing the formation of local bright portions while preserving the beneficial curved appearance.
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 reduces brightness unevenness by regulating light reflection, ensuring a more uniform light distribution across the display panel.
Implementation Method 1
The total reflection regulator is disposed on at least a portion of the curved end surface and configured to regulate an amount of light in the opposite end portion to be totally reflected by the curved end surface
Implementation Method 2
The light collecting portion includes light collecting pieces extending on the light exiting surface in a normal direction with respect to the light entering end surface and arrayed in an orthogonal direction perpendicular to the normal direction
Data Source
AI summary
A backlight unit includes an LED, a light guide plate, a light collecting portion, an opposite end portion, and a total reflection regulator. The light guide plate includes a light entering end surface opposed to the LED and a light exiting surface that is one of plate surfaces. The light collecting portion includes light collecting pieces extending on the light exiting surface in a normal direction to the light entering end surface and arrayed in an orthogonal direction perpendicular to the normal direction. The opposite end portion is on an opposite side from the light entering end surface. A section of the opposite end portion includes a curved end surface. The total reflection regulator is disposed on at least a portion of the curved end surface and configured to regulate the amount of light in the opposite end portion to be totally reflected by the curved end surface.