Laser-Patterned Connection Film Pieces for Micro-LED Transfer
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Solution Overview
Problem
Existing methods for manufacturing mini-LED and micro-LED displays face challenges in achieving excellent light transmissive properties and productivity due to issues with attaching connection films like ACF directly below LEDs, leading to poor transferability and increased tact time.
Innovation Solution
A method involving a mask with a light-shielding portion of a predetermined shape is used to irradiate laser light on a curable resin film, forming individualized pieces with a reaction rate of 25% or less, which are then transferred and mounted onto a wiring substrate to create a display device, utilizing shapes like polygons with obtuse angles, ellipses, or circles to enhance workability and transferability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ACF is entirely pasted to the element mounting surface of the substrate, then the connection between LEDs and substrate is ensured, but the light transmissive properties deteriorate due to adhesive resin and conductive particles remaining between adjacent LEDs
Solution Approach 1:
The connection film is divided into individualized pieces, each corresponding to a specific LED position. This segmentation allows the film to be applied only where needed (directly below LEDs) rather than covering the entire substrate surface, thereby maintaining light transmissive properties between LEDs while ensuring reliable electrical connection at each LED location.
Solution Approach 2:
The adhesive resin and conductive particles are concentrated only in the regions directly below the LEDs, rather than being uniformly distributed across the entire substrate. This local quality approach ensures reliable connection at LED positions while leaving the spaces between LEDs free of obstructions, allowing light to pass through unimpeded.
2Illumination intensity
If ACF is attached only directly below the LEDs, then light transmissive properties are improved, but the transferability and workability deteriorate due to poor shape of individualized pieces
Solution Approach 1:
The individualized pieces are designed with curved or rounded shapes rather than sharp geometric forms. This spheroidality principle improves the transferability of the individualized pieces during the manufacturing process, as curved shapes are more tolerant of handling and positioning variations, thereby enhancing workability while maintaining the light transmissive properties between LEDs.
3Manufacturing precision
If the individualized pieces are attached after forming, then the connection precision can be achieved, but the tact time for display manufacturing increases
Solution Approach 1:
The individualized pieces are pre-formed with their final shapes and positions determined in advance using a mask during the laser irradiation process. This preliminary action allows the pieces to be ready for immediate transfer and attachment, eliminating the need for time-consuming post-formation handling and positioning operations, thereby reducing tact time while maintaining connection precision.
Solution Approach 2:
The mask-based laser irradiation system replaces traditional mechanical cutting or punching methods for forming individualized pieces. This substitution enables precise formation and simultaneous preparation of multiple pieces in a single operation, significantly reducing the time required compared to sequential mechanical processing, thus improving productivity while ensuring connection precision.
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 approach improves the processability and transferability of individualized pieces, reducing tact time and ensuring excellent light transmissive properties in the display device.
Implementation Method 1
A mask having a light-shielding portion of a predetermined shape that blocks laser light within an opening that allows laser light to pass through
Implementation Method 2
irradiating a curable resin film formed on a base material with laser light from the base material side to remove the curable resin film in the irradiated area
Implementation Method 3
forming individualized pieces of a predetermined shape composed of the curable resin film with a reaction rate of 25% or less on the base material
Data Source
Figure 1
Figure 2(A)~2(D)
Figure 3(A)~3(B)
AI summary
Provided is a mask and a method for manufacturing the mask with excellent processability and transferability of individualized pieces, as well as a method for manufacturing a display device and a display device. By using a mask having a predetermined shape of a light-shielding portion that blocks laser light within an opening that transmits laser light, laser light is irradiated from the base material (21) side to the curable resin film (22) formed on the base material (21) to remove the curable resin film (22) in the irradiated portion (removal portion (23)), thereby forming individualized pieces of a predetermined shape composed of a curable resin film (22) with a reaction rate of 25% or less on the base material (21). This allows for excellent workability and transferability of the individualized pieces, thereby improving tact time.