Pixel Circuit Transistor Count Reduction for Display Uniformity
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Solution Overview
Problem
Conventional pixel circuits for organic EL displays require a large number of transistors, which can reduce the aperture ratio and pose challenges in achieving high-precision displays, especially as resolutions increase, due to variations in transistor characteristics affecting image uniformity.
Innovation Solution
A simplified pixel circuit configuration using four or three transistors and one capacitor element, where specific transistors are selectively conducted in response to scan signals and light emission control signals to compensate for threshold voltage variations, reducing the number of elements while maintaining high picture quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large number of transistors are used in the pixel circuit to compensate for variations in transistor characteristics, then picture quality is improved, but the aperture ratio is reduced
Solution Approach 1:
The patent extracts and removes unnecessary transistors from the pixel circuit while retaining only the essential ones needed for variation compensation. By carefully analyzing which transistors are critical for maintaining picture quality and which can be eliminated, the invention reduces the transistor count from six or more to four or fewer, thereby increasing the aperture ratio while preserving picture quality through the retention of key compensation transistors.
2Manufacturing precision
If the number of transistors in the pixel circuit is increased to achieve high-precision display, then display precision is improved, but the reliability is reduced due to increased failure risk
Solution Approach 1:
The patent removes redundant transistors from the pixel circuit that are not essential for achieving high-precision display. By extracting only the necessary transistors for variation compensation and display functionality, the invention reduces the total transistor count, thereby lowering the probability of failure while maintaining display precision through optimized use of remaining critical transistors.
Solution Approach 2:
The patent changes the operational parameters and control signals of the remaining transistors to compensate for the reduced number of elements. By optimizing the gate signals, scan signals, and light emission control signals for the simplified circuit configuration, the invention maintains display precision despite having fewer transistors, thereby improving reliability without sacrificing picture quality.
3Stability of the object's composition
If more transistors are used in the pixel circuit for variation compensation, then image uniformity is improved, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates redundant transistors from the pixel circuit while preserving the essential transistors needed for image uniformity. By removing unnecessary elements and simplifying the circuit topology, the invention reduces device complexity while maintaining image uniformity through the optimized configuration of remaining transistors that perform variation compensation.
Solution Approach 2:
The patent designs the remaining transistors to perform multiple functions simultaneously. Each transistor in the simplified circuit is configured to handle multiple tasks such as switching, compensation, and signal routing, thereby reducing the total number of transistors needed while maintaining image uniformity. This multi-functionality approach reduces circuit complexity without sacrificing performance.
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 reduced number of elements in the pixel circuit achieves high picture quality by compensating for transistor variations, improving display uniformity and enabling high-precision displays with fewer transistors, thus addressing the limitations of conventional designs.
Implementation Method 1
The electroluminescence phenomenon is a phenomenon in which the state of an electron of a material (an organic EL element) changes from the ground state to the excited state so as to return from the excited state, which is unstable, to the ground state, which is stable, whereby the difference of energy is emitted in the form of light.
Data Source
AI summary
A pixel circuit includes: a light emitting element whose cathode is connected to a first power source for supplying a first power supply voltage; a first transistor having a first terminal connected to a data line and having a gate terminal; a second transistor connected between the gate terminal of the first transistor and a second terminal of the first transistor and having a gate terminal; a third transistor connected between the second terminal of the first transistor and an anode of the light emitting element and having a gate terminal; a fourth transistor connected between the gate terminal of the first transistor and an initialization power source and having a gate terminal; and a capacitor having one end connected to a power source for supplying a voltage having a fixed potential and the other end connected to the gate terminal of the first transistor.