Variable Shaped Mask Synchronization for Exposure Efficiency
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Solution Overview
Problem
The existing exposure methods for manufacturing large liquid crystal display devices are inefficient in utilizing light energy, leading to reduced illuminance, increased costs, and decreased processing speed due to the need for high-output light sources or slower scanning speeds to accommodate the unstable operation times of movable mirrors in mask-less exposure apparatus.
Innovation Solution
An exposure method and apparatus that synchronizes light emission with the operation state of a variable shaped mask, using a Q-switch laser to emit pulses only during the stable time of the movable mirrors, thereby optimizing energy usage and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a continuous light source is used in mask-less exposure apparatus, then the light emission covers both operation time and stable time, but the energy during operation time is wasted and illuminance is reduced
Solution Approach 1:
The patent applies periodic action by using a pulsed light source that emits light only during the stable time when micromirrors are positioned correctly, rather than continuous emission. This synchronizes light emission with the operational cycle of the DMD, eliminating waste during operation time while maintaining sufficient illuminance during effective exposure time.
2Use of energy by moving object
If a large output light source is used to ensure energy during stable time, then the cost increases, but the energy utilization efficiency remains low
Solution Approach 1:
By implementing periodic pulsed emission synchronized with mirror stable time, the system achieves high energy utilization efficiency without requiring a large output light source. The light source operates at standard output levels but only emits during productive periods, reducing overall energy consumption and associated costs while maintaining effective exposure energy delivery.
3Productivity
If the scanning speed is lowered to extend stable time, then the processing speed decreases, but the energy utilization improves
Solution Approach 1:
The pulsed light emission approach allows maintaining high scanning speeds because light is emitted only during stable time when exposure is effective. This eliminates the need to slow down scanning to extend stable time, as the system achieves high energy utilization efficiency through temporal synchronization rather than extended exposure duration, thereby preserving productivity.
4Manufacturing precision
If a large mask is used for large liquid crystal display devices, then the mask thickness must be increased to suppress deflection, but the manufacturing cost increases
Solution Approach 1:
The patent extracts the pattern formation function from a physical mask entirely by using a mask-less exposure apparatus with a DMD. The variable shaped mask is formed dynamically by controlling micromirror positions, eliminating the need for thick physical masks and associated costs for mask manufacturing, maintenance, and inspection while achieving the required pattern precision.
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 enhances energy utilization efficiency, maintains illuminance, and increases processing speed while reducing costs, enabling the production of micro devices at a lower cost with improved productivity.
Implementation Method 1
using a Q-switch laser to emit pulses only during the stable time of the movable mirrors
Implementation Method 2
When the mirror is ON, light from a light source is reflected toward a projection optical system
Data Source
AI summary
An exposure device includes: a light source (LS) which emits a pulse light; and a variable shaped mask (8) which has a plurality of aligned micro movable mirrors and forms an arbitrary pattern by selectively changing the operation state of the movable mirrors. A substrate (P) is exposed to the light emitted from the light source and passes through the variable shaped mask. The exposure device further includes a control device (100) which controls the operation timing to change the operation state of the movable mirrors and the pulse application timing of the pulse light emitted from the light source so that they are synchronized.