Frameless LCD Driver IC Integration via Substrate Cavity
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Solution Overview
Problem
Existing LCD packaging technologies are complex and costly, leading to dead space in display modules due to the use of anisotropic conductive films and bulky driver IC mounting methods, which reduces the usable display area and increases manufacturing expenses.
Innovation Solution
The implementation of a driver cavity within the TFT array substrate and a redistribution layer (RDL) to integrate the driver IC directly into the LCD panel, eliminating the need for anisotropic conductive films and reducing surface traces, with a flexible printed circuit (FPC) electrically coupled to the driver IC for signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If driver IC is mounted using COG or COF method with anisotropic conductive films, then electrical connection between driver IC and LCD panel is achieved, but dead space is created and display area is reduced
Solution Approach 1:
The driver IC is integrated directly into the LCD panel by forming driver circuit patterns on the same substrate as the pixel array, eliminating the need for separate driver IC mounting. This merging of driver function and display substrate removes the dead space required for external driver mounting while maintaining electrical connectivity through integrated conductive patterns.
Solution Approach 2:
The driver circuit patterns are formed on the back surface of the LCD panel substrate, utilizing the z-dimension (thickness direction) to resolve the spatial conflict. By positioning driver circuits on the opposite side of the pixel array, the design eliminates dead space on the front display surface while providing adequate space for driver IC mounting on the back surface.
2Ease of manufacture
If driver IC is mounted on external PCB or FPC, then driving circuits can be provided, but overall footprint is larger than actual display area
Solution Approach 1:
The driving circuit patterns are merged with the pixel array patterns on the same substrate, creating a unified integrated circuit structure. This eliminates the need for separate external PCB or FPC assemblies, reducing the overall footprint to match the actual display area while maintaining manufacturing feasibility through standard thin-film fabrication processes.
Solution Approach 2:
The LCD panel substrate serves dual functions: as the display surface for pixel array and as the mounting substrate for driver circuits. This multi-functionality eliminates the need for separate dedicated driver mounting substrates, reducing overall footprint while maintaining ease of manufacture through integrated fabrication.
3Reliability
If conventional driver IC mounting methods are used, then driver IC can be connected to LCD panel, but manufacturing cost increases due to complexity
Solution Approach 1:
The driver circuit patterns are formed using the same thin-film fabrication processes as the pixel array, merging two previously separate manufacturing sequences into one. This integration eliminates complex packaging steps such as anisotropic conductive film application, precise alignment, and separate bonding operations, reducing device complexity while maintaining connection reliability.
Solution Approach 2:
The fabrication process parameters are optimized to form both pixel array patterns and driver circuit patterns in the same processing sequence, changing the manufacturing approach from sequential separate fabrication to simultaneous integrated fabrication. This parameter change reduces process complexity and manufacturing cost while ensuring reliable electrical connections.
Data Source
AI summary
Disclosed is a display module and method of manufacturing the same, where the display module comprises a LCD panel, a driver IC for driving the LCD panel, and a FPC electrically coupled to the driver IC. The LCD panel includes an array of TFT pixels on a TFT array substrate. The TFT array substrate defines a driver cavity and one or more die cavities in which the driver IC and one or more other IC dies are disposed. The driver IC includes an image signal input pad and a driving signal output pad. The driver IC is configured to receive image signals from the FPC, to process the image signals into drive signals, and to transmit the drive signals to TFT pixels via an RDL electrical connection and a through-glass via through the TFT array substrate.