Deposition Mask With Unevenness Region For Alignment Mark Recognition
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Solution Overview
Problem
In organic light emitting diode (OLED) display device manufacturing, aligning masks with transparent substrates is challenging due to small contrast differences between alignment marks, leading to potential alignment errors and increased defective rates.
Innovation Solution
A mask for deposition with a mask alignment mark and an unevenness region having protrusions and depressions is used, which diffuses incident light, and a flat region for reflection, enhancing the recognition of alignment marks and preventing alignment errors by improving light reflection and contrast differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mask for deposition is aligned on a transparent substrate, then the deposition pattern can be formed, but the contrast difference between alignment marks is small due to reflected light from the mask surface, making it difficult to confirm the location of alignment marks
Solution Approach 1:
The patent converts the harmful reflected light into a beneficial effect by creating an unevenness region that intentionally diffuses light. This diffuse reflection from the uneven surface enhances the visibility of alignment marks by creating sufficient contrast between the mark region and surrounding areas, thereby solving the original problem of poor contrast on transparent substrates.
Solution Approach 2:
The patent applies local quality by creating a specific unevenness region with protrusions and depressions only in the area adjacent to alignment marks, while other regions of the mask maintain their original flat surface. This localized modification improves alignment mark recognition without affecting the overall mask function or other areas.
2Measurement precision
If the mask surface is made uneven to improve alignment mark visibility, then the recognition rate of alignment marks increases, but the mask structure becomes more complex
Solution Approach 1:
The unevenness is introduced only in specific regions adjacent to alignment marks rather than across the entire mask surface. This localized approach improves alignment mark recognition while minimizing the increase in overall structural complexity and maintaining simplicity in other mask regions.
Solution Approach 2:
The mask surface is segmented into different functional regions: flat regions for normal deposition and unevenness regions specifically for alignment mark enhancement. This segmentation allows the mask to perform multiple functions with minimal additional complexity, as each region is optimized for its specific purpose.
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 effectively increases the recognition rate of alignment marks, reducing alignment errors and manufacturing costs by improving the accuracy of mask alignment on transparent substrates, thereby decreasing defective OLED display devices.
Implementation Method 1
an unevenness region formed on one surface of the mask member so as to be adjacent to the mask alignment mark and having protrusions and depressions on a surface thereof. The unevenness region may diffused-reflect incident light.
Implementation Method 2
a flat region formed between the mask alignment mark and the unevenness region and having a flat surface. The flat region may reflect incident light.
Data Source
AI summary
A mask for deposition for forming a pattern on a transparent substrate according to the present invention includes a mask member having a mask alignment mark penetratedly formed so as to be aligned with a substrate alignment mark formed on the transparent substrate; and an unevenness region formed on one surface of the mask member so as to be adjacent to the mask alignment mark and having protrusions and depressions on a surface thereof. In accordance with embodiments of the present invention, it is possible to prevent the alignment error of the mask from occurring by increasing the recognition rate of the align marks formed on the substrate and the mask. As a result, it is possible to reduce the manufacturing costs by reducing the defective rate of the organic light emitting diode (OLED) display device.