Mini-LED Bezel Bonding for Seamless Spliced LCD Panels
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Solution Overview
Problem
The seams between display areas of adjacent LCD display panels in spliced display devices are large, limiting their market presence to middle to low-end segments due to temperature-related issues during reflow soldering, which affect the liquid crystal molecules and polarizers, and also result in a ghosting phenomenon due to uncontrolled solder paste printing.
Innovation Solution
A manufacturing method for display devices that involves creating pad units and conductive units on the bezel area of the LCD display panel, where mini-LEDs are then attached. This method uses either anisotropic conductive adhesive or solder paste for the conductive units, and employs hot pressing or laser heating to form the conductive connections, allowing for local heating and avoiding the issues associated with reflow soldering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If reflow soldering is used to bond mini-LEDs to LCD display panels, then the bonding strength is improved, but the liquid crystal molecules are irreversibly decomposed and polarizers lose effectiveness due to high temperature
Solution Approach 1:
The patent changes the temperature parameter from high-temperature reflow soldering (>180°C) to low-temperature processing (<120°C) to avoid decomposing liquid crystal molecules and degrading polarizers, while still achieving adequate bonding strength through alternative methods
Solution Approach 2:
The patent replaces the thermal field (reflow soldering) with a mechanical field (cold pressing) to achieve bonding without high temperature, thereby protecting the temperature-sensitive liquid crystal and polarizer components
2Area of stationary object
If the size of steel mesh is increased for printing solder pastes on large-size LCD display panels, then the coverage area is improved, but the steel mesh bends due to its own weight causing uncontrolled solder paste amount and ghosting phenomenon
Solution Approach 1:
The patent divides the large-size LCD display panel into multiple smaller printing regions, allowing the steel mesh to be used at an appropriate size for each region without bending, thereby maintaining printing precision while covering the entire panel through multiple printing passes
Solution Approach 2:
The patent performs multiple printing passes on different regions of the panel rather than attempting to print the entire large area in one pass, ensuring precise control of solder paste amount in each region while achieving complete coverage
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 method effectively eliminates seams between display areas of adjacent LCD panels, improves the screen ratio of the display device, and enhances product competitiveness by preventing the ghosting phenomenon and maintaining the effectiveness of the liquid crystal layers and polarizers.
Implementation Method 1
manufacturing a plurality of conductive units spaced apart from each other on one side of the pad units away from the LCD display panel, wherein, the conductive units are correspondingly electrically connected to the pad units by one to one, and a material of the conductive units is an anisotropic conductive adhesive or a solder paste
Implementation Method 2
employs hot pressing or laser heating to form the conductive connections
Data Source
AI summary
A manufacturing method of a display device, the display device, and a spliced display device are disclosed. The display device includes a liquid crystal display panel (LCD display panel), a plurality of pad units, a plurality of conductive units, and a plurality of mini light-emitting diodes (mini-LEDs). The mini-LEDs are manufactured in a bezel area of the LCD display panel to allow the bezel area of the LCD display panel which does not emit light and display originally to display by the mini-LEDs, thereby improving a screen ratio of the display device and improving product competitiveness of the spliced display device.