Non-Rectangular LCD Backlight Uniform Illumination
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Solution Overview
Problem
Conventional liquid crystal display devices with non-rectangular backlight shapes, particularly those with corners greater than 90°, suffer from uneven brightness due to light distribution issues, where light tends to concentrate in the center rather than reaching the corners effectively.
Innovation Solution
The liquid crystal display device employs a light guide plate matching the backlight's shape, with LEDs aligned along the corners to ensure light propagation in the same direction, and includes a deflection mechanism to redirect light, ensuring uniform illumination across the screen by aligning LEDs on two sides to emit light perpendicular to the sides and using a refractive or reflective deflection means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If light emitting diodes are aligned along two sides forming a corner with angle greater than 90° perpendicular to the sides, then the structure matches the non-rectangular backlight shape, but the corner regions become low-brightness areas due to light concentration in the center
Solution Approach 1:
The backlight unit is divided into multiple light guide plates, each responsible for a specific region. By segmenting the light guide into multiple plates with different shapes and sizes, the patent achieves both non-rectangular overall shape and uniform brightness distribution, as each segment can be optimized for its specific function
Solution Approach 2:
Different regions of the backlight unit are assigned different optical properties and LED arrangements. The patent applies local quality by having LEDs arranged perpendicular to long sides for edge illumination, while corner regions use different arrangements, and each light guide plate has region-specific optical characteristics to ensure uniform brightness throughout
2Ease of manufacture
If light emitting diodes are aligned perpendicular to the sides of the light guide plate, then the LED arrangement is simple, but the light propagates mainly towards the center causing uneven brightness distribution
Solution Approach 1:
The patent employs asymmetric LED arrangements where LEDs are positioned and oriented differently based on their location. LEDs along long sides are arranged perpendicular to those sides, while LEDs in corner regions and along short sides have different orientations, creating an asymmetric but optimized light distribution pattern that prevents center concentration
Solution Approach 2:
The patent transitions from simple one-dimensional LED alignment to a two-dimensional arrangement strategy. By considering both the position and orientation of LEDs in multiple dimensions, and by stacking multiple light guide plates in the vertical dimension, the system achieves comprehensive light coverage and uniform brightness distribution
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 achieves uniform brightness distribution across the screen, preventing low-brightness regions at corners by directing light to reach the edges rather than concentrating it in the center, thereby enhancing overall illumination quality.
Implementation Method 1
the main light for illumination from the light emitting diodes aligned along the above-described two sides propagates through the light guide plate in a same direction
Implementation Method 2
a deflection means for changing the direction of the light emitted from the light emitting diodes is provided between the light guide plate and the light emitting diodes along one of the above-described two sides of the light guide plate
Data Source
AI summary
The liquid crystal display device has a liquid crystal display panel, a backlight for illuminating the liquid crystal display panel where the outer shape of the backlight in a plane has at least one corner of which the angle is greater than 90°, and a light guide plate LG having approximately the same form as the outer shape of the backlight, wherein a number of light emitting diodes are aligned along two sides (s1, s3) of the light guide plate LG that form a corner A of which the angle is greater than 90°, and the main light for illumination (L2 to L4, L6 and L7) from the light emitting diodes aligned along the two sides propagates through the light guide plate LG in the same direction.