Integrated Display Sensor Read Circuit Speed Stabilization
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Solution Overview
Problem
Liquid crystal display devices with integrated photoelectric conversion elements face challenges in reliable data reading due to differences in amplifier characteristics, leading to unstable detection results and slow data read speeds, especially when used as operation panels for high-speed touch operations.
Innovation Solution
A display device with a matrix arrangement of display elements and optical sensors, utilizing a read circuit and read signal processing means to efficiently process and transfer sense signals, and an amplifier setup that adjusts input voltage to maintain stability and enhance read speed by effectively utilizing signal lines without increasing components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photoelectric conversion elements are integrated on the array substrate to enable additional image loading function, then the display device gains touch operation sensing capability, but data read speed becomes insufficient for high-speed touch operations
Solution Approach 1:
The patent segments the readout process by introducing separate read signal lines distinct from display signal lines, allowing simultaneous display operation and sensor data reading. This segmentation enables independent optimization of read speed without affecting display performance, resolving the contradiction between touch sensing capability and data read speed.
Solution Approach 2:
The patent implements preliminary charging of capacitors connected to photoelectric conversion elements before readout operations. By pre-charging the capacitors to a reference voltage level, the system prepares the sensor nodes in advance, enabling rapid voltage comparison and faster data reading when touch events occur, thus improving read speed for high-speed touch operations.
2Power
If TFT amplifiers are constructed on the glass substrate to amplify optical sensor outputs, then signal amplification is achieved, but marked differences in characteristics between amplifiers cause unstable detection results
Solution Approach 1:
The patent implements a feedback mechanism where the actual output characteristics of each TFT amplifier are measured and stored. During readout operations, the system retrieves the corresponding amplifier characteristics and uses this feedback information to compensate for variations, normalizing the detection results across all sensors. This feedback approach maintains signal amplification while eliminating the reliability issues caused by amplifier characteristic differences.
Solution Approach 2:
The patent changes the operational parameters of the amplifiers by adjusting bias voltages and operating points to optimize performance. By dynamically adjusting amplifier parameters based on measured characteristics, the system compensates for manufacturing variations and achieves stable detection results while maintaining adequate signal amplification capability.
3Device complexity
If the same signal lines are used for both display data input and sensor data reading to avoid increasing components, then device complexity is reduced, but signal interference and crosstalk occur
Solution Approach 1:
The patent resolves the conflict by adding a temporal dimension to the signal line usage. During display periods, signal lines carry display data; during sensor readout periods, the same lines carry sensor data. This time-division multiplexing approach allows single-use signal lines to handle multiple functions without interference, reducing device complexity while eliminating crosstalk through temporal separation of operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables flexible data processing, improves read speed, and stabilizes detection results by compensating for amplifier differences, ensuring reliable and efficient operation in high-speed touch applications.
Implementation Method 1
a photoelectric conversion element connected to an input of the amplifier
Data Source
AI summary
An input sensor containing a display device including a group of pixel circuits arranged in a matrix, a group of optical sensor circuits arranged in a matrix, a display driving circuit which provides a display signal to the display element group and which provides a driving signal to the display element group, a read circuit which identifies an optical sensor to read a sense signal from this optical sensor, and a read signal processing section which processes the sense signal output by the read circuit in accordance with a command. The read signal processing section has an interface section which transfers, when the command requesting execution of an application is set to the interface section, the command to a command register.