Plastic Substrate Laser Lift-Off for Active Matrix Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for manufacturing active matrix displays on plastic substrates face challenges such as fragility, wastefulness, and difficulty in producing thin, transparent, and non-birefringent substrates, particularly due to the limitations of polyimide materials used in laser lift-off processes.
Innovation Solution
A method involving a wet casting process to apply a transparent plastic material with a UV-absorbing additive to a rigid carrier substrate, allowing for laser release and forming thin film electronic elements, which enhances substrate handling and processing while maintaining transparency and non-birefringence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polyimide is used as the plastic substrate material for laser lift-off, then high-temperature stability is achieved, but the substrate becomes yellowish and birefringent, making transmissive and polarization-dependent displays difficult to manufacture
Solution Approach 1:
The patent changes the material parameters by selecting transparent plastics (polycarbonate, silicone) with different thermal and optical properties than polyimide, then adjusts the laser wavelength parameter (308-351 nm or 355 nm) to match the absorption characteristics of these new materials through UV doping, achieving both transparency and laser responsiveness
Solution Approach 2:
The patent creates a composite material system by doping transparent plastic substrates with UV-absorbing additives, combining the transparency of the plastic with the laser-absorption capability of the UV dopant, thereby achieving both optical clarity and laser lift-off functionality
2Illumination intensity
If typical transparent materials such as polycarbonate or silicones are used, then transparency is achieved, but they do not absorb sufficient UV energy to be lifted off by a laser release process
Solution Approach 1:
The patent introduces a UV-absorbing additive as an intermediary substance that mediates between the transparent plastic substrate and the laser energy, allowing the transparent material to absorb UV energy indirectly through the dopant molecules without compromising its optical clarity
Solution Approach 2:
The patent modifies the energy absorption parameter of transparent plastics by doping them with UV-absorbing additives, changing their optical absorption characteristics at UV wavelengths (308-351 nm or 355 nm) while maintaining transparency in the visible spectrum
3Strength
If glass substrates are used for AMLCD manufacturing, then structural strength is achieved, but the displays become thick and heavy, and HF thinning process is required which is wasteful and hazardous
Solution Approach 1:
The patent replaces rigid glass substrates with thin plastic film substrates that can be made extremely thin (enabling displays thinner than 0.8 mm) while maintaining sufficient mechanical strength through the plastic material properties and manufacturing process, eliminating the need for HF thinning
Solution Approach 2:
The patent uses plastic substrates that can be manufactured more economically and disposed of or recycled more easily than glass, eliminating the need for hazardous HF etching processes and reducing manufacturing complexity
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
Enables the production of thin, flexible, and transparent active matrix displays using standard manufacturing processes, reducing material waste and environmental hazards, and allowing for the reuse of glass substrates, thus facilitating mass production of plastic displays.
Implementation Method 1
This UV absorber absorbs in the wavelength of the lift-off laser (for example 308-351 nm, or 355 nm) with a very high absorption coefficient μ (for example >104 cm−1)
Data Source
AI summary
A method of manufacturing a thin film electronic device includes applying a plastic coating to a rigid carrier substrate using a wet casting process, the plastic coating forming a plastic substrate and include a transparent plastic material doped with a UV absorbing additive. Thin film electronic elements are formed over the plastic substrate, and the rigid carrier substrate is released from the plastic substrate. This method forms transparent substrate materials suitable for a laser release process, through doping of the plastic material of the substrate with a UV absorber. This UV absorber absorbs in the wavelength of the lift-off laser (for example 308-351 nm, or 355 nm) with a very high absorption.