Light Guide Plate Sag Control Patterns Backlight Unit
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Solution Overview
Problem
Existing methods for manufacturing white dot patterns in backlight units face limitations in fill factor, leading to suboptimal light emission control, efficiency, and uniformity, with challenges in mass production, development lead time, and light loss due to manufacturing complexities and defects.
Innovation Solution
A backlight unit with sag control patterns on a light guide plate, where optical patterns, such as micro lenses, are arranged to increase in sag as they move away from the light source, improving fill factor and light efficiency, and featuring a diffusion and reflection layer for enhanced light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If white dot patterns are manufactured using injection molding, then manufacturing is simple, but mass production is vulnerable to bending and achieves low yield rate
Solution Approach 1:
The patent replaces mechanical injection molding with laser processing to create optical patterns on the light guide plate. This substitution eliminates the mechanical bending issues and improves yield rate while maintaining manufacturing simplicity through direct laser writing capability.
Solution Approach 2:
The patent changes the manufacturing parameters by using laser processing instead of injection molding. This parameter change allows for precise control of optical pattern formation, improving both yield rate and manufacturing flexibility without compromising simplicity.
2Loss of time
If white dot patterns are manufactured using printing method, then development lead time and production period are reduced with excellent reproducibility, but manufacturing process is sophisticated requiring additional facilities and may suffer defect in large volume
Solution Approach 1:
The patent replaces sophisticated printing processes with direct laser processing. This substitution maintains excellent reproducibility and reduces development lead time while simplifying the manufacturing process by eliminating the need for additional printing facilities and reducing defect rates in large volume production.
3Productivity
If white dot patterns are manufactured using stamping method, then reproducibility is excellent and mass production is simplified, but entire development period grows longer when production model is changed
Solution Approach 1:
The patent replaces stamping with laser processing, which maintains excellent reproducibility and mass production capability while significantly reducing development period. The direct laser writing method allows for rapid prototyping and production model changes without the time-consuming stamping tooling processes.
4Ease of operation
If white dot patterns are arranged to control light emission angles, then light emission control is improved, but fill factor is limited and light efficiency decreases
Solution Approach 1:
The patent changes the parameter of optical pattern sag height to improve light efficiency while maintaining light emission control. By optimizing the sag parameter of the optical patterns, the patent achieves better light extraction efficiency without compromising the ability to control emission angles, thereby reducing energy loss.
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 solution enhances light efficiency and uniformity by controlling the sag of optical patterns, allowing for improved light emission angles and areas, reducing manufacturing time and costs, and overcoming limitations in fill factor and light loss.
Implementation Method 1
light emitted from a light source propagates through a light guide plate making total reflection. The critical angle for total reflection is determined by the ratio of a refractive index of a propagation medium to that of air layer
Implementation Method 2
The critical angle for total reflection is determined by the ratio of a refractive index of a propagation medium to that of air layer, which can be derived from Snell's law
Data Source
AI summary
The present invention relates to a backlight unit with sag control patterns, comprising a light source formed in a side surface of a light guide plate; and a plurality of optical patterns formed on a lower surface of the light guide plate, sag of the plurality of optical patterns increasing as the optical patterns become more distant from the light source. By controlling sag of optical patterns formed in a light guide plate, efficiency of light emitted from a backlight unit can be improved and uniformity of the light can be maintained. Also, since sag of optical patterns can be controlled, by increasing the number of optical patterns (by improving fill factor), light efficiency and uniformity can be controlled easily. Also, compared with a conventional method for manufacturing white dot patterns, white dot patterns can be more efficiently manufactured in terms of development time and costs.