Backlight Unit QD Bar Fastening for LCD Color Reproduction
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Solution Overview
Problem
Existing backlight units for LCD devices using white LEDs suffer from limited color reproduction and efficiency due to the use of a single color LED package, and the adhesion methods for quantum dot (QD) bars between LEDs and light guide plates are inconvenient, leading to productivity issues and light distortion.
Innovation Solution
A backlight unit design featuring a blue LED light source with a QD bar positioned between the LED and the light guide plate, where the QD bar is fastened using a supporting frame and fastening units such as printed circuit boards, heat sinking plates, and middle molding parts to prevent heat transfer and light distortion, allowing for improved color reproduction and manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a quantum dot bar is adhered between the blue LED and the light guide plate using optical resin layer or adhesive layer, then the QD bar can be fixed in position, but productivity decreases and light distortion occurs
Solution Approach 1:
The patent removes the optical resin layer or adhesive layer from the assembly process. Instead of adhering the QD bar to the light guide plate, the QD bar is positioned and fixed directly within a groove structure formed in the light guide plate itself, eliminating the need for separate adhesion materials and steps.
Solution Approach 2:
The fixing function and light guide function are merged into a single integrated structure. The groove in the light guide plate serves both as a positioning feature for the QD bar and as part of the light guiding path, combining structural support and optical function into one component.
2Reliability
If optical resin layer or adhesive layer is used to adhere the QD bar, then the QD bar can be fixed, but the light emitted from the LED and QD bar is distorted
Solution Approach 1:
The patent eliminates the optical resin layer or adhesive layer that causes light distortion. By removing this intermediate material, the light path from the LED through the QD bar to the light guide plate becomes direct, preventing distortion while maintaining QD bar fixation through the groove structure.
3Temperature
If heat generated by the LED is transferred to the light guide plate via optical resin layer or adhesive layer, then heat can be dissipated, but the light guide plate twists and damages the QD bar
Solution Approach 1:
The patent removes the optical resin layer or adhesive layer that acts as a thermal insulation barrier. This allows heat generated by the LED to be directly dissipated from the light guide plate, preventing thermal accumulation that would cause twisting and QD bar damage.
Solution Approach 2:
The groove structure in the light guide plate serves as a thermal intermediary, providing a direct thermal pathway from the LED to the light guide plate while simultaneously serving as a mechanical fixation structure for the QD bar, eliminating the need for separate adhesion materials.
4Device complexity
If a single LED package emitting one color is used, then the device structure is simple, but color reproduction is limited to 75% of NTSC area
Solution Approach 1:
The patent changes the wavelength parameter of the light source by using a blue LED combined with a quantum dot bar. The quantum dot bar converts the blue light to other wavelengths, enabling the system to achieve broader color reproduction (100% NTSC area) while maintaining relatively simple device structure.
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 enhances color reproduction and productivity by preventing heat transfer and light distortion, ensuring the QD bar is securely fastened without adhesives, thus improving the backlight unit's performance and manufacturing ease.
Implementation Method 1
a quantum dot (QD) bar which is arranged between the lateral side of the light guide plate and the light source and changes a color of the light emitted from the light source
Implementation Method 2
Light emitted from the LED 10 enters the lateral sides of the light guide plate 20, propagates to the center of the light guide plate 20 by total reflection
Data Source
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AI summary
A backlight unit is provided which includes: a light guide plate which guides incident light from a lateral side of the light guide plate toward a liquid crystal display (LCD) panel placed in front of the light guide plate; a light source unit which includes a light source which emits the light and a light source supporting member which supports the light source and is arranged adjacent to the lateral side of the light guide plate; a supporting frame which is arranged in the backlight unit; a quantum dot (QD) bar which is arranged between the lateral side of the light guide plate and the light source and changes a color of the light emitted from the light source; and a QD-bar fastening unit which fastens the QD bar to at least one of the light source supporting member and the supporting frame.