Flexible Circuit Feedback Electrode for Touch Noise Compensation
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Solution Overview
Problem
In LCD devices with touch screens, noise in the common voltage affects the sensing signal, reducing the touch sensitivity of the touch IC due to the complexity and increased cost of adding noise compensation functions to the touch IC.
Innovation Solution
An FPC with a feedback compensation signal electrode and touch lines is used to connect the touch screen and touch board, receiving a feedback compensation signal to counteract noise in the panel, thereby improving touch sensitivity without complicating the touch IC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If noise compensation function is added to the touch IC, then touch sensitivity is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces an FPC as an intermediary component between the touch screen and touch IC. The FPC includes a feedback compensation signal electrode that receives the feedback compensation signal from the main board and transmits it to the touch IC, thereby separating the noise compensation function from the touch IC itself. This allows the touch IC to remain simple while still achieving noise compensation and improved touch sensitivity through the intermediary FPC structure.
Solution Approach 2:
The patent implements a feedback mechanism where the main board generates a feedback compensation signal based on noise detected from the panel, and this signal is transmitted through the FPC to the touch IC. The touch IC then uses this feedback signal to compensate for noise in the sensing signal, achieving continuous noise cancellation and maintaining high touch sensitivity without requiring complex internal noise compensation circuits in the touch IC.
2Measurement precision
If noise compensation function is added to the touch IC, then touch sensitivity is improved, but manufacturing cost increases
Solution Approach 1:
By using the FPC as an intermediary to carry the feedback compensation signal, the patent avoids the need to manufacture complex noise compensation circuits within the touch IC. The noise compensation function is implemented in the main board and transmitted through the FPC, which simplifies the touch IC manufacturing process and reduces overall system cost while maintaining improved touch sensitivity.
3Object-generated harmful factors
If feedback compensation signal electrode is added to FPC, then noise removal capability is improved, but FPC structure becomes more complex
Solution Approach 1:
The patent applies local quality by adding the feedback compensation signal electrode only at specific locations within the FPC where it is needed to transmit the compensation signal. The FPC maintains its basic flexible circuit structure with touch lines for signal transmission, while locally incorporating the feedback compensation signal electrode to receive and transmit the noise compensation signal. This localized addition minimizes overall FPC structural complexity while achieving effective noise removal.
Data Source
AI summary
Discussed is a Flexible Printed Circuit (FPC). The FPC includes a plurality of touch lines respectively connected to a plurality of touch electrode lines, a first film adhered to the touch lines, a second film overlapping the first film at an upper end surface of the first film and covering the touch lines, and a feedback compensation signal electrode adhered to a lower end surface of the first film, and receiving a feedback compensation signal for removing noise.