Voltage-Supply Circuit for Touch-Display Initialization
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Solution Overview
Problem
In touch-control display technology, the transition from touch-control mode to display mode is hindered by RC-delay effects, causing horizontal touch line effects due to the slow drop of voltage levels on common-electrode blocks, which affects the display of subpixels.
Innovation Solution
A voltage-supply circuit with a driver integrated circuit (IC) that includes a voltage-supply sub-circuit, a voltage-feedback sub-circuit, and a voltage-comparison sub-circuit to quickly transition from touch-control scan voltage to standard common-electrode voltage by generating a trigger signal based on feedback voltage polarity changes, thereby reducing the initialization period and eliminating horizontal touch line effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If touch-control scan voltage signals are inserted within display time to improve report rate, then touch control report rate is improved, but horizontal touch line effects occur due to RC-delay during voltage transition
Solution Approach 1:
An initialization period is inserted at the beginning of each display time to pre-charge or pre-discharge the common-electrode block to a predetermined initialization voltage before the normal display voltage is applied. This preliminary action ensures that when the common-electrode block transitions from touch-control mode to display mode, the voltage starts from a known state, preventing the RC-delay effect from causing horizontal touch line effects during the transition.
Solution Approach 2:
The voltage level of the common-electrode block is changed in a controlled manner through three stages: initialization voltage (during initialization period), normal display voltage (during normal output period), and touch-control scan voltage (during touch-control period). By introducing an intermediate initialization voltage state and controlling the transition timing through feedback comparison, the patent eliminates the harmful voltage transition effects while maintaining high report rate.
2Speed
If common-electrode block voltage transitions from touch-control scan voltage to standard common-electrode voltage, then display mode operation is achieved, but voltage level drops slowly due to RC-delay effect
Solution Approach 1:
A feedback sub-circuit is configured to detect the actual voltage level of the common-electrode block in real-time. The detected feedback voltage is compared with a reference voltage by a comparison sub-circuit. When the feedback voltage reaches the reference voltage (indicating complete transition), the comparison sub-circuit generates a trigger signal to end the initialization period. This feedback mechanism ensures reliable voltage transition completion detection, preventing display quality issues while achieving fast transition speed.
Solution Approach 2:
The initialization period is established as a predetermined time interval at the beginning of each display time, during which the common-electrode block voltage is actively controlled to transition to the normal display voltage. This preliminary action ensures that the voltage transition is completed before normal display operation begins, eliminating the RC-delay problem while maintaining reliable display quality.
3Object-affected harmful factors
If voltage level on common-electrode block is maintained during transition period, then horizontal touch line effects are eliminated, but initialization period time increases
Solution Approach 1:
The feedback sub-circuit continuously monitors the common-electrode block voltage level during the initialization period. The comparison sub-circuit compares the feedback voltage with the reference voltage and generates a trigger signal immediately when the voltage reaches the reference level. This feedback mechanism allows the initialization period to end as soon as the voltage transition is complete, minimizing the initialization time while ensuring horizontal touch line effects are eliminated.
Solution Approach 2:
The initialization period duration is made dynamic rather than fixed. It automatically adjusts based on the actual voltage transition speed of the common-electrode block, which varies depending on the RC-delay characteristics and circuit conditions. The period ends when the feedback voltage reaches the reference voltage, making the initialization time adaptive to actual circuit behavior, thus minimizing time loss while ensuring display quality.
Data Source
AI summary
The present application discloses a voltage-supply circuit including a voltage-supply sub-circuit coupled to a plurality of common-electrode blocks respectively via a plurality of signal lines in a display panel and configured to provide an initializing common-electrode voltage to each common-electrode block via a respective one signal line during an initialization period of a display time. The voltage-supply circuit further includes a voltage-feedback sub-circuit configured to collect a feedback voltage from the respective one signal line during the initialization period. Additionally, the voltage-supply circuit includes a voltage-comparison sub-circuit configured to compare the feedback voltage and a standard common-electrode voltage and to cause a generation of a trigger signal when a difference between the feedback voltage and the standard common-electrode voltage changes polarity. The trigger signal drives the voltage-supply sub-circuit in a normal output period to supply the standard common-electrode voltage via the respective one signal line to one corresponding common-electrode block.