In-Cell Touch Display Signal Lines as Sensing Electrodes
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Solution Overview
Problem
The manufacturing of in-cell type touch display devices is hindered by the need for separate masks and increased costs due to the limitations in forming touch wiring near pixel circuits, which requires additional photolithographic processes and incompatible modes for display, readout, and touch functions.
Innovation Solution
The in-cell type touch display device integrates signal lines that function as sensing electrodes without an additional photolithographic process, using time division mode to manage display, readout, and touch operations, with signal lines serving multiple functions and expansions formed from the same material, reducing the need for separate masks and enhancing manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If touch wiring is formed in another metal layer separate from the conventional pixel circuit wiring, then the touch function can be integrated into the display panel, but a separate mask is required in the manufacturing process which increases cost and manufacturing time
Solution Approach 1:
The patent merges the touch wiring formation process with the conventional pixel circuit wiring formation process by using the same mask pattern. The touch wiring is formed simultaneously with the pixel circuit wiring in the same metal layer, eliminating the need for a separate mask and separate manufacturing step. This integration directly resolves the contradiction by maintaining touch function integration while reducing manufacturing process complexity
Solution Approach 2:
The same mask pattern serves dual purposes: it defines both the conventional pixel circuit wiring and the touch wiring in a single manufacturing step. This multi-functionality of the mask pattern eliminates the need for additional photolithographic processes, thereby reducing cost and manufacturing time while maintaining the integrated touch display function
2Ease of manufacture
If the region for forming touch wiring is limited by the conventional pixel circuit wiring region, then the manufacturing process is simplified, but the touch electrode coverage and functionality are reduced
Solution Approach 1:
The patent extends the touch wiring into the peripheral region beyond the conventional pixel circuit wiring region, utilizing the peripheral area of the display panel for additional touch electrode coverage. This dimensional extension allows the touch wiring to cover a larger area without complicating the manufacturing process, as the same mask pattern can be applied across the entire panel including peripheral regions
Data Source
AI summary
A touch display device according to an exemplary embodiment of the present inventive concept includes: a plurality of pixel circuits; a plurality of first signal lines respectively connected to the plurality of pixel circuits and extending in a first direction; and a plurality of second signal lines respectively connected to the plurality of pixel circuits and extending in a second direction, wherein at least one signal line among the plurality of first signal lines and the plurality of second signal lines function as a first sensing electrode and a second sensing electrode in the touch mode, respectively.