Display Device Drive Blocks for Threshold Voltage Correction
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Solution Overview
Problem
Conventional display devices face increased drive circuit output load and difficulty in precise threshold voltage correction as the display panel area increases, leading to luminance unevenness and reduced image quality.
Innovation Solution
The display device is organized into drive blocks with two signal lines per column and control lines per row, featuring a light-emitting element, drive transistor, capacitive elements, and switching transistors, allowing for uniform threshold voltage correction periods within each block, reducing signal switching frequency, and enhancing drive current precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display panel area is increased, then the display device can provide larger display area, but the drive circuit output load increases and threshold voltage correction precision deteriorates
Solution Approach 1:
The display panel is divided into multiple drive blocks, with each block independently correcting threshold voltages for its pixels. This segmentation allows the correction operation to be performed in parallel across multiple blocks, reducing the overall correction time and maintaining precision even as the total display area increases.
Solution Approach 2:
The patent performs threshold voltage correction during the period when the light-emitting element is not emitting light (non-light-emission period). By conducting the correction operation in advance during this idle period, the system ensures that threshold voltage compensation is completed before the next light-emission cycle begins, maintaining image quality without extending the overall frame time.
2Loss of energy
If the drive circuit output load is reduced, then power consumption decreases, but the threshold voltage correction precision may be compromised
Solution Approach 1:
By dividing the display into multiple drive blocks that correct threshold voltages in parallel, the correction operation is distributed across multiple independent circuits. This reduces the peak output load on any single drive circuit while maintaining overall correction precision through simultaneous operation of all blocks.
Solution Approach 2:
The threshold voltage correction is performed periodically during the non-light-emission period of each frame cycle. This periodic action allows the drive circuit to operate at lower average power levels while still achieving precise correction at the required intervals, balancing power consumption with correction precision.
3Measurement precision
If the threshold voltage correction period is extended, then correction precision improves, but the light emission duty ratio decreases
Solution Approach 1:
The threshold voltage correction is performed in advance during the non-light-emission period, before the light-emission period begins. This preliminary action ensures that correction precision is achieved without encroaching on the light-emission time, maintaining high duty ratio while allowing sufficient correction duration.
Solution Approach 2:
By segmenting the display into multiple drive blocks that correct threshold voltages in parallel, the total correction time required for the entire display is reduced. Each block performs correction simultaneously, allowing the system to achieve high precision correction without extending the overall frame time or reducing the light emission duty ratio.
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
This configuration reduces the load on drive circuits, enables precise drive current flow to light-emitting elements, and improves image display quality by extending the threshold voltage correction period within a frame, maintaining high luminance even with increased display area.
Implementation Method 1
Display devices using organic electroluminescence (EL) elements are well-known as display devices using current-driven light-emitting elements
Implementation Method 2
a first capacitive element that includes terminals, one of the terminals being connected to the gate of the drive transistor; a second capacitive element that includes terminals
Data Source
AI summary
A display device including pixels has formed therein at least two drive blocks each made up of pixel rows. Each of the pixels includes: a drive transistor; a first electrostatic capacitor and a second electrostatic capacitor; an organic EL element; a first switching transistor provided between the source and the drain of the drive transistor; and a second switching transistor that supplies a signal current to the organic EL element. Each of the pixels in a kth drive block includes a third switching transistor provided between a first signal line and the first electrostatic storing capacitor, and each of the pixels in a k-th drive block includes a fourth switching transistor provided between a second signal line and the first electrostatic storing capacitor. A second control line for controlling conduction of the first switching transistor is connected to each of the pixels in a same one of the drive blocks.