Backlight Unit Bank Mask for Brightness Uniformity
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Solution Overview
Problem
Direct-illumination type backlight units often suffer from non-uniform brightness due to hot spots, and existing manufacturing methods are costly and prone to damaging pre-formed solder parts during the production of backlight units.
Innovation Solution
A method involving a bank mask with a protective groove is used to form a bank on a printed circuit board, surrounding the solder part and light emitting unit, which changes the light path and reduces hot spots, while using a screen printing method to minimize damage to the solder part and enable mass production at lower costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a bank is formed on the printed circuit board using conventional manufacturing methods, then the bank can change the light path to reduce hot spots, but the solder part may be damaged during the bank formation process
Solution Approach 1:
The solder part is formed first on the printed circuit board before the bank is formed. This preliminary action allows the solder part to be in place and protected during subsequent bank formation processes, preventing damage that would occur if banking was done first
Solution Approach 2:
A mask is used as an intermediary tool during bank formation. The mask protects the solder part from direct contact with bank formation materials and processes, allowing the bank to be formed adjacent to the solder part without causing damage
2Ease of manufacture
If conventional manufacturing methods are used for producing backlight units, then production can proceed, but the manufacturing cost is high and mass production is difficult
Solution Approach 1:
The manufacturing process is segmented into distinct sequential steps: first forming the solder part, then forming the bank, and finally assembling the light emitting unit. This segmentation allows each step to be optimized independently and facilitates automation for mass production
Solution Approach 2:
The manufacturing method changes the process parameters by performing bank formation after solder part formation, rather than before. This parameter change in process sequencing enables the use of cost-effective manufacturing techniques that support mass production
3Device complexity
If the bank mask is aligned without a protective groove, then the alignment process is simpler, but the solder part is exposed to damage during bank material application
Solution Approach 1:
The protective groove is pre-formed in the mask structure before bank material application. This preliminary structural preparation ensures that when bank material is applied, it naturally flows into the groove and protects the solder part without requiring complex real-time adjustment mechanisms
Solution Approach 2:
The protective groove acts as an intermediary structure between the mask and the solder part. It provides a physical barrier and containment space that protects the solder part from direct exposure to bank formation processes while maintaining simple mask geometry
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 improves brightness uniformity by reducing hot spots and lowers manufacturing costs through effective protection of solder parts during the production of backlight units, enabling efficient mass production.
Implementation Method 1
a bank on the printed circuit board, adjacent to a side surface of the light emitting unit, covered by the lens part and configured to change a path of a light exiting from the side surface of the light emitting unit
Implementation Method 2
configured to change a path of a light exiting from the side surface of the light emitting unit such that the light travels to outside the lens part
Implementation Method 3
The forming the solder part may be performed by a screen printing method using a solder mask provided with a second opening defined therethrough to correspond to the first area of the printed circuit board
Implementation Method 4
The connecting the light emitting unit and the solder part may be performed by a reflow-soldering process
Data Source
AI summary
A manufacturing method of a backlight unit includes providing a solder paste on a printed circuit board and forming a solder part in a first area of the printed circuit board, aligning a bank mask on the printed circuit board to align a first opening defined through the bank mask with a second area of the printed circuit board not overlapped with the first area, providing a bank material in the first opening and forming a bank on the printed circuit board in an area corresponding to the second area, separating the bank mask from the printed circuit board including the bank thereon, and connecting the solder part of the printed circuit board and a light emitting unit to each other.