UV-Curable Resin Adhesion for LCD Front Window
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Solution Overview
Problem
The reduced thickness of liquid crystal display panels makes them prone to mechanical destruction, and existing methods for attaching a front window to prevent this, such as using an adhesive with a refractive index similar to glass, require a reduced pressure atmosphere, increasing costs and reducing throughput due to the need for bubble prevention and accurate resin distribution.
Innovation Solution
The method involves using ultraviolet curable resin to adhere the front window to the liquid crystal display panel at atmospheric pressure, with partial temporary curing to maintain flowability, allowing for accurate setting of resin thickness and area, and complete curing later, enabling efficient and bubble-free attachment without the need for reduced pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the liquid crystal display panel thickness is reduced to decrease set size and panel thickness, then the outer dimension and thickness are reduced, but the mechanical strength decreases making the panel prone to destruction
Solution Approach 1:
A front window is attached to the liquid crystal display panel before final assembly, serving as a protective structure that prevents mechanical destruction. This preliminary protective measure allows the panel to be used with reduced thickness without compromising strength.
2Strength
If the front window is attached apart from the liquid crystal display panel to protect it from external force, then mechanical protection is provided, but doubly contoured images occur due to light reflection at the interface
Solution Approach 1:
The refractive index of the adhesive material is changed to match that of the front window and liquid crystal display panel. This parameter adjustment eliminates light reflection at the interfaces, preventing doubly contoured images while maintaining mechanical protection.
Solution Approach 2:
An adhesive material with matched refractive index serves as an intermediary between the front window and liquid crystal display panel. This intermediary eliminates optical interference while providing mechanical bonding and protection.
3Reliability
If ultraviolet curable resin is used to adhere the front window and liquid crystal display panel in reduced pressure atmosphere to prevent bubbles, then bubble-free adhesion is achieved, but device cost increases and throughput decreases
Solution Approach 1:
The mechanical vacuum system is replaced with a chemical/photochemical solution. Ultraviolet curable resin is applied at atmospheric pressure, then cured using ultraviolet light to prevent bubble formation without requiring vacuum equipment, thereby simplifying the system and improving throughput.
Solution Approach 2:
The adhesive material undergoes a phase transition from liquid to solid through ultraviolet light-induced curing. This phase change occurs rapidly at atmospheric pressure, eliminating the need for vacuum drying processes and improving manufacturing efficiency.
4Reliability
If ultraviolet curable resin is used in reduced pressure atmosphere to allow uniform distribution, then bubble-free adhesion is achieved, but the process time increases due to the necessary waiting period
Solution Approach 1:
The ultraviolet curable resin is applied and positioned at atmospheric pressure before curing. The preliminary application step allows rapid uniform distribution without vacuum processing, and subsequent ultraviolet irradiation quickly cures the resin, reducing total process time.
Solution Approach 2:
The vacuum-based distribution process is replaced with ultraviolet light-based curing. This substitution eliminates the time-consuming vacuum chamber operation and drying period, achieving both uniform distribution and bubble-free adhesion more rapidly.
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 allows for accurate and efficient adhesion of the front window to the liquid crystal display panel at atmospheric pressure, improving operational rates and reducing costs by preventing mechanical destruction and ensuring high image quality without the drawbacks of reduced pressure methods.
Implementation Method 1
the adhesive material is cured by ultraviolet light so as to prevent generation of bubbles in the ultraviolet curable resin
Data Source
AI summary
A distance between a liquid crystal display panel set on a lower support mechanism and a front window set on an upper support mechanism is accurately determined by a stopper. An ultraviolet irradiation mask is provided on the front window. A part of the ultraviolet curable resin corresponding to a transmission pattern of the ultraviolet irradiation mask is temporarily cured through ultraviolet irradiation. The temporarily adhered structure of the liquid crystal display panel and the front window is taken from an attachment device to be left standing for a predetermined time period on a tray until an area and a thickness of the ultraviolet curable resin reach respective predetermined values. The ultraviolet light is then irradiated to an entire surface of the ultraviolet curable resin to finalize the adhesion. The time for which the attachment device is occupied is short, thus improving an operation rate of the device.