Watch LCD Polarizer Bonding with Alignment Targets and Cut Marks
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Solution Overview
Problem
Existing manufacturing processes for liquid crystal display devices in watches result in misalignment of polarizers, leading to visible silvery crescents at the edge of the LCD screen, indicating poor quality.
Innovation Solution
A precise manufacturing process for liquid crystal display devices that allows for the accurate alignment of front and rear polarizers relative to the electrodes, ensuring they only partially cover the visible area, using targets and alignment marks for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If polarizers are made smaller than the display window to create a floating display area, then the floating display effect is achieved, but misalignment between polarizers becomes clearly visible at the edge of the LCD screen
Solution Approach 1:
The patent applies preliminary action by pre-positioning alignment marks and targets before the polarizer assembly process. Alignment marks are formed on the substrate before the polarizers are applied, and targets are created on the polarizer support structure. This allows for precise alignment to be established in advance, ensuring that when the polarizers are assembled, they will be correctly positioned relative to each other and to the display window, thereby resolving the misalignment issue while maintaining the floating display effect.
Solution Approach 2:
The patent uses an intermediary approach by introducing a polarizer support structure with targets as a mediator between the alignment marks and the final polarizer positioning. This support structure with its specifically formed targets serves as an intermediate reference system that facilitates precise alignment. The targets on the support structure are aligned with the alignment marks on the substrate, and this intermediary structure ensures that the polarizers are correctly positioned without requiring direct precise positioning during assembly.
2Manufacturing precision
If polarizers are precisely aligned to eliminate visible misalignment, then manufacturing precision is improved, but the complexity of the manufacturing process increases
Solution Approach 1:
The patent applies self-service by designing a manufacturing process where the alignment marks and targets are self-aligning features that automatically guide the polarizer positioning. The alignment marks formed on the substrate and the corresponding targets on the polarizer support structure are designed to be mutually aligned through the manufacturing process itself, eliminating the need for complex external alignment procedures. The process is self-regulating, where the geometry of the alignment features ensures precise positioning without requiring additional complex alignment steps or equipment.
3Adaptability or versatility
If polarizers partially cover the visible area to create display area, then the floating display effect is achieved, but alignment precision becomes more difficult to maintain
Solution Approach 1:
The patent applies the color changes principle by using visually distinct alignment marks and targets that can be easily detected and measured. The alignment marks and targets are designed with specific optical characteristics that make them visible and measurable during the alignment process. This allows for precise measurement and verification of the polarizer positioning, ensuring that the partial coverage required for the floating display effect is achieved with high alignment precision. The optical visibility of the alignment features enables accurate measurement without requiring complex measurement equipment.
Data Source
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AI summary
The process for manufacturing a liquid crystal display (LCD) cell, forming a clock display device, comprises forming a base assembly (32), including two transparent plates on which the electrodes (28, 29) are structured, and a cover assembly (66) including a working portion (50) formed by a polarizer and a layer of adhesive for fixing the polarizer to one of the transparent plates. To ensure precise deposition of the polarizer, targets (30a, 30c) are formed in the base assembly, and corresponding alignment marks (48a, 48c) are cut into at least one working portion of the cover assembly, so that the targets can be seen through the alignment marks when the cover assembly is placed on the base assembly during the bonding of the polarizer to the base assembly.Preferably, at least one working portion of the target is removed from the LCD cell after the polarizer has been bonded to the transparent plate, at least partially above the electrodes. Otherwise, the targets and at least one working portion of the target are advantageously arranged outside a usable area of the LCD cell.