Scan Driver Signal Segmentation for Display Sensing
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Solution Overview
Problem
Existing display devices face challenges in accurately sensing the mobility and deterioration of light-emitting elements, particularly when the device is in a powered-on state, as current technologies lack effective methods to differentiate between scan signals and sensing signals.
Innovation Solution
A scan driver is designed with multiple scan signal output circuits, each comprising a driving circuit, a first buffer circuit, and a second buffer circuit, which apply specific driving signals and clock signals to generate scan and sensing signals on separate lines, allowing for accurate mobility and deterioration sensing of light-emitting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If scan signals and sensing signals are transmitted through the same scan line, then the device complexity is reduced, but the measurement precision of mobility and deterioration sensing deteriorates
Solution Approach 1:
The patent divides the single scan line into two separate scan lines: a first scan line for transmitting scan signals and a second scan line for transmitting sensing signals. This segmentation allows the sensing operation to be performed independently without interference from scan signals, thereby improving measurement precision while maintaining reasonable device complexity through dedicated signal paths.
2Measurement precision
If scan signals and sensing signals are transmitted simultaneously through separate lines, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The scan driver is designed to perform multiple functions: it can output scan signals to the first scan line and sensing signals to the second scan line, and can also operate in display mode by outputting scan signals to both lines. This multi-functionality allows the same hardware structure to support both display operations and sensing operations without requiring completely separate circuits, thereby managing device complexity while achieving high measurement precision.
3Productivity
If the display device is in a powered-on state during sensing, then the productivity is improved, but the measurement precision deteriorates due to signal interference
Solution Approach 1:
By segmenting the scan lines into separate channels for scan signals and sensing signals, the patent enables simultaneous operation of display and sensing functions without signal interference. The first scan line carries scan signals for display operation while the second scan line carries sensing signals for mobility and deterioration sensing, allowing both functions to operate concurrently with high precision even when the device is powered on.
Data Source
AI summary
A scan driver includes two or more scan signal output circuits (SSOC), each being coupled to a first scan line (FSL) and a second scan line (SSL), and including a driving circuit, a first buffer circuit (FBC), and a second buffer circuit (SBC). The driving circuit applies a first driving signal (DS) to a first driving node (DN) and applies a second DS to a second DN based on an input signal, a clock signal (CS), a display-on signal, and an on-level voltage. The input signal is a scan start signal or a previous scan signal. The FBC outputs a sensing signal to the SSL based on the first DS, the second DS, an off-level voltage, and a sensing CS. The SBC outputs a scan signal to the FSL based on the first DS, the second DS, the off-level voltage, and a scan CS.