Laser Crystallization Vibration for Energy Uniformity
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Solution Overview
Problem
The existing silicon crystallization methods using laser beams face challenges in maintaining energy uniformity in the longer-axis direction, leading to degradation in display quality and the formation of stripe pattern blurs in polycrystalline silicon thin films due to optical system defects and increasing size of flat panel displays.
Innovation Solution
A silicon crystallization system that includes a vibration device to periodically and randomly change the vibration frequency of the laser beam in the longer-axis direction, using a vibration frequency controller and optical system with a homogenizer array and lens groups to ensure uniform energy distribution and prevent pattern blurs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the laser beam is made longer in the longer-axis direction to enhance productivity, then the productivity is improved, but the energy uniformity in the longer-axis direction degrades
Solution Approach 1:
The patent applies mechanical vibration to the optical system components (mirrors or homogenizer arrays) to dynamically modulate the laser beam path. This vibration causes the laser energy to be distributed more uniformly across the longer-axis direction, preventing concentration of energy in specific regions while maintaining the extended beam length required for high productivity.
Solution Approach 2:
The patent introduces dynamic elements into the optical system, making components movable rather than fixed. By dynamically adjusting the position of mirrors or homogenizer arrays during laser irradiation, the system maintains energy uniformity across the extended beam length, resolving the contradiction between beam length and energy distribution uniformity.
2Area of stationary object
If the divided laser beams overlap in a larger area to cover larger display devices, then the coverage area is improved, but the energy uniformity degrades due to optical characteristics and system defects
Solution Approach 1:
The patent employs mechanical vibration of optical components to dynamically redistribute laser energy across the overlap region. This vibration effect compensates for optical system defects and characteristic non-uniformities, ensuring uniform energy distribution even when beams overlap over large areas to cover extended display devices.
Solution Approach 2:
The patent incorporates feedback mechanisms that monitor the energy distribution of overlapping laser beams and dynamically adjust the vibration parameters or optical component positions. This feedback control compensates for deviations caused by optical characteristics and system defects, maintaining energy uniformity across the expanded coverage area.
3Device complexity
If a fixed vibration frequency is used to simplify the control system, then the device complexity is reduced, but stripe pattern blurs form due to laser beam vibration
Solution Approach 1:
The patent changes the frequency parameter of laser beam vibration from a fixed value to a randomly varying value. This parameter change prevents the formation of stationary interference patterns that cause stripe blurs, while the random variation is simple enough to implement without significantly increasing control system complexity.
Solution Approach 2:
The patent employs periodic vibration of the laser beam with randomly varying frequencies. This periodic action with random frequency modulation effectively eliminates stripe pattern blurs by preventing consistent interference patterns, while maintaining a relatively simple control architecture through the use of random number generators or frequency modulation circuits.
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 system enhances energy uniformity and reduces stripe pattern blurs, improving the quality of polycrystalline silicon thin films and preventing instability and delay in data input/output, thus improving display characteristics.
Implementation Method 1
a vibration device configured to vibrate a linear laser beam in a longer-axis direction of the linear laser beam, the vibration device being configured to periodically generate and randomly change a vibration frequency
Implementation Method 2
An optical system using the homogenizer serves to divide a laser beam in particular directions by a homogenizer array and make the respective divided layer beams overlap on the same plane, to thereby make the energy distribution of the laser beam more uniform
Implementation Method 3
irradiating a high energy laser beam onto an amorphous silicon thin film deposited on a glass substrate. Upon receiving the laser beam, the amorphous silicon thin film is melted by the heat and then solidified so as to be crystallized
Implementation Method 4
the amorphous silicon thin film is melted by the heat and then solidified so as to be crystallized
Implementation Method 5
the amorphous silicon thin film is melted by the heat and then solidified so as to be crystallized
Data Source
AI summary
A silicon crystallization system includes a vibration device for vibrating a linear laser beam along a longer-axis direction of the linear laser beam. A vibration frequency at which the laser beam is vibrated is periodically generated and randomly changes within a predetermined range.