Shift Register Bridge Stages for Touch Panel Stage Rotation
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Solution Overview
Problem
In in-cell type liquid crystal display panels, certain stages of the shift register deteriorate due to repeated enablement during touch sensing periods, leading to horizontal line defects and display failures, which affect product reliability.
Innovation Solution
A shift register design with bridge stages between adjacent block regions allows stages to be driven in association with each other during touch sensing periods, preventing deterioration by alternating image display and touch sensing periods within each frame period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If scan pulses are sequentially supplied to gate lines during touch sensing periods, then touch sensing can be performed, but certain stages of the shift register deteriorate due to repeated enablement
Solution Approach 1:
The shift register is divided into multiple block regions (first block region, second block region, etc.), with each block containing multiple stages. Bridge stages are inserted between adjacent block regions to enable independent control and operation of each block, allowing rotation of which block is active during touch sensing periods.
Solution Approach 2:
The shift register operates in periodic cycles where different block regions are activated alternately during image display periods and touch sensing periods. During each touch sensing period, a specific block region is enabled while others remain disabled, and this pattern rotates across different blocks over time, ensuring periodic rest for all stages.
2Productivity
If the same stages are repeatedly kept in enabled state during each touch sensing period, then touch sensing operation continues, but horizontal line defects occur due to repeated deterioration
Solution Approach 1:
The bridge stages are pre-configured to receive carry pulses from the last stage of each block region and to enable the first stage of the next block region. This preliminary setup allows seamless transition between blocks and ensures that when one block is disabled for touch sensing, the next block is already prepared to take over, preventing continuous stress on the same stages.
Solution Approach 2:
During touch sensing periods, certain block regions are temporarily discarded (disabled) while others are used. After the touch sensing period ends, the previously discarded blocks are recovered and re-enabled for image display, while other blocks are disabled. This continuous rotation ensures all blocks get periodic rest and recovery time.
Data Source
AI summary
A shift register provided to an in-cell touch panel, an image display including the same, and a method of driving the same. The shift register has a plurality of stages dependently connected to one another and includes first to nth stages dependently connected to one another in each of a plurality of block regions divided according to an image display period and a touch sensing period alternating plural times during each frame period; and first and second bridge stages disposed between each pair of adjacent block regions. According to the present invention, the shift register includes a plurality of bridge stages between each adjacent pair of adjacent stages among a plurality of stages divided according to an image display period and a touch sensing period to allow the plurality of stages to be driven in association with one another even during the touch sensing period, thereby preventing deterioration of specific stages. The shift register can prevent an abnormal screen such as a horizontal line defect in an image display panel, reduce a defect rate, and enhance customer satisfaction, thereby improving reliability of a product.