Input Sensing Circuit With Signal Multiplexing for Low-Noise FOD
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Solution Overview
Problem
Display devices with integrated fingerprint sensors face issues of increased size and manufacturing costs due to the large number of output lines and stage circuits, which also reduce sensing sensitivity due to excessive noise.
Innovation Solution
An input sensing device with a horizontal driver, selection circuit, and vertical driver, incorporating an integration circuit with an amplifier, capacitor, and initialization switch, along with a correlated double sampling circuit, to minimize the size and cost of the reset driver and improve sensing sensitivity by reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of output lines and stage circuits are used to transmit sensing signals from photo sensors, then the FOD can sense biometric information, but the device size increases and manufacturing cost increases
Solution Approach 1:
The patent merges multiple signal transmission functions into a single output line by using time-division multiplexing. The selection circuit sequentially connects multiple photo sensors to one output line, allowing sensing signals from multiple sensors to be transmitted through a single line at different time slots, thereby reducing the number of output lines from many to one.
Solution Approach 2:
The patent segments the signal transmission process into multiple time slots, where each time slot is dedicated to transmitting signals from a specific photo sensor. The selection circuit switches between different sensors in each time slot, enabling sequential transmission of sensing signals through a single output line without signal interference.
2Reliability
If a large number of output lines and stage circuits are used to transmit sensing signals from photo sensors, then the FOD can sense biometric information, but the manufacturing cost increases
Solution Approach 1:
The patent merges multiple signal transmission functions into a single output line by using time-division multiplexing. The selection circuit sequentially connects multiple photo sensors to one output line, allowing sensing signals from multiple sensors to be transmitted through a single line at different time slots, thereby reducing the number of output lines from many to one.
3Reliability
If a large number of output lines and stage circuits are used to transmit sensing signals, then the FOD can sense biometric information, but excessive noise is produced that reduces sensing sensitivity
Solution Approach 1:
The patent extracts and removes the noise problem by using a single output line instead of multiple parallel lines. By consolidating signal transmission into one line with time-division multiplexing, the patent eliminates the crosstalk and interference that occur between multiple adjacent signal lines, thereby reducing noise and improving sensing sensitivity.
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 effectively minimizes the size and manufacturing cost of the input sensing device while enhancing its sensing sensitivity by integrating the sensing signals and reducing external noise.
Implementation Method 1
The capacitor includes a first electrode connected to the first input terminal and a second electrode connected to the output terminal
Implementation Method 2
A fingerprint sensor to sense the biometric information may be embedded within the display device
Data Source
AI summary
An input sensing device includes: sensor pixels, a horizontal driver, a selection circuit, and a vertical driver. Each of the sensor pixels is connected to a plurality of driving lines and a one of a plurality of signal input lines. The horizontal driver sequentially applies a horizontal driving signal to the sensor pixels through the driving lines. The selection circuit is connected to n of the signal input lines (n is a natural number of 2 or more) and to one output line. The selection circuit sequentially outputs n sensing signals received through the n signal input lines to the one output line. The vertical driver receives the n sensing signals through the one output line. The horizontal driver applies the horizontal driving signal n times to a given one of the driving lines to correspond to the n sensing signals.