Photomask Light-Transmission Patterns for Uniform Optical Alignment
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Solution Overview
Problem
Conventional optical alignment methods for liquid crystal displays result in un-exposed or under-exposed areas during the fabrication of Multi-Mode Glass products, leading to issues like mura (non-uniform brightness) and reduced substrate utilization due to the need for increased spacing between substrate units to avoid overlapping exposure zones.
Innovation Solution
A photomask design with interlacing light-transmission patterns of varying heights arranged in a specific pattern to ensure seamless alignment and exposure across substrate units, preventing un-exposed or under-exposed areas by aligning the tail ends of one pattern with the starting ends of another, thereby reducing the necessary spacing between substrate units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple photomasks are combined to cover large substrate areas, then substrate coverage is improved, but overlapping areas receive double light irradiation causing un-exposed or under-exposed regions
Solution Approach 1:
The photomask is divided into multiple independent photomask figures (first photomask figure, second photomask figure, etc.) arranged in different directions on the same photomask body. Each photomask figure can be independently positioned and exposed, allowing precise control over exposure areas without overlapping interference from adjacent figures.
Solution Approach 2:
A spacing structure is introduced between adjacent photomask figures to act as an intermediary element. This spacing structure prevents light from one photomask figure from reaching the overlapping area of adjacent figures, thereby eliminating the double irradiation problem while still allowing the photomask figures to cover large substrate areas.
2Manufacturing precision
If spacing distance between substrate units is increased to avoid overlapping exposure issues, then exposure uniformity is improved, but substrate utilization decreases
Solution Approach 1:
The photomask figures are segmented into distinct directional groups (first direction DX and second direction DY) with spacing structures between them. This segmentation allows adjacent substrate units in different directions to be exposed independently without interference, enabling closer spacing between substrate units while maintaining exposure uniformity.
Solution Approach 2:
Different regions of the photomask are designed with different light transmission characteristics. The spacing structures are strategically placed only where needed to prevent overlapping exposure, while other regions maintain full light transmission. This localized quality adjustment optimizes both exposure uniformity and substrate utilization.
3Adaptability or versatility
If photomask figures are arranged to cover different substrate unit sizes, then adaptability is improved, but alignment precision between different substrate units deteriorates
Solution Approach 1:
The photomask body serves multiple functions by accommodating different types of photomask figures (first photomask figure for first substrate units, second photomask figure for second substrate units) on the same mask. This universal design allows a single photomask to handle substrate units of different sizes and arrangements, improving adaptability while maintaining alignment precision through the spacing structure.
Solution Approach 2:
The spacing structure acts as an intermediary reference that maintains consistent spacing relationships between photomask figures of different types. This intermediary element ensures that regardless of the substrate unit size or configuration, the alignment precision is maintained through uniform spacing patterns.
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 solution ensures uniform exposure across the substrate units, eliminating mura issues and increasing substrate utilization by allowing for closer packing of substrate units without un-exposed areas, thus enhancing the alignment performance and efficiency of the optical alignment process.
Implementation Method 1
Optical alignment is a non-contact alignment technique, which uses linearly polarized light to irradiate, through a photomask, a high-molecule polymer alignment film that is sensitive to light so as to form an alignment microstructure that has a predetermined inclination angle
Data Source
AI summary
A photomask (2) for optical alignment and an optical alignment method. By aligning the tail ends of first light-transmission patterns (313) which form a first photomask figure (3), and aligning the front ends of second light-transmission patterns (413), which form a second photomask figure (4) in the photomask (2), the un-exposed or underexposed areas do not exist at the tail ends of first substrate units (11) and the front end of second substrate units (12) during the process of optical alignment, thereby the problem existed in the traditional optical alignment manufacture process, that the brightness of a display is not uniform due to existing unexposed or underexposed areas, is solved, meanwhile, the reduction of the distance between the first substrate units (11) and the second substrate units (12) on a substrate is facilitated, thereby the utilization rate of the substrate is improved.