Electro-optical Device Digital Driving Pixel Circuit
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Solution Overview
Problem
Existing organic electro-luminescence (EL) devices in head-mounted displays face challenges in achieving high-resolution, multi-grey-scale, and low power consumption due to variations in voltage-current characteristics and threshold voltages of drive transistors, leading to decreased display quality and increased power consumption.
Innovation Solution
The electro-optical device incorporates a pixel circuit with a memory circuit between potential lines, a second transistor connected to the scan line, and a light emitting element and first transistor in series between high and low potential lines, allowing for digital driving with binary signals, reducing the influence of transistor variations and eliminating the need for a compensating circuit, thus enabling finer pixels and lower power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a compensating circuit is provided to compensate for variations in voltage-current characteristics and threshold voltages of drive transistors, then display quality is improved, but power consumption increases
Solution Approach 1:
The patent extracts and eliminates the compensating circuit from the pixel circuit configuration. By using a memory circuit to store digital signals and a simple drive transistor to drive the light emitting element, the complex compensating circuit is removed entirely, achieving both high display quality and low power consumption without the need for compensation components.
Solution Approach 2:
The patent replaces the analog voltage control mechanism with a digital signal storage and control mechanism. Instead of using analog voltage levels that require compensation for transistor variations, the invention uses digital signals stored in a memory circuit, which are then converted to drive signals by a simple transistor, eliminating the need for compensating circuits.
2Adaptability or versatility
If the capacitance of a capacitor that stores an image signal is increased to achieve more grey-scales of display, then the number of grey-scales is improved, but device area increases and power consumption increases
Solution Approach 1:
The patent segments the grey-scale control into multiple subfields within a single frame period. Instead of using a large capacitor to store analog voltage representing grey-scale levels, the invention divides the display into multiple time-sequential subfields, each controlled by digital signals. This allows multi-grey-scale display without requiring large storage capacitance, thereby reducing device area.
Solution Approach 2:
The patent employs periodic action by dividing each frame into multiple subfields that are displayed in sequence. Each subfield is controlled by digital signals that are periodically updated. This time-sequential approach enables multi-grey-scale display through temporal modulation rather than spatial capacitor sizing, reducing the required device area.
3Adaptability or versatility
If the capacitance of a capacitor that stores an image signal is increased to achieve more grey-scales of display, then the number of grey-scales is improved, but power consumption increases due to charge and discharge of the capacitor
Solution Approach 1:
The patent segments the grey-scale control into multiple subfields within a single frame period. Instead of using a large capacitor to store analog voltage representing grey-scale levels, the invention divides the display into multiple time-sequential subfields, each controlled by digital signals. This allows multi-grey-scale display without requiring large storage capacitance, thereby reducing device area.
Solution Approach 2:
The patent employs periodic action by dividing each frame into multiple subfields that are displayed in sequence. Each subfield is controlled by digital signals that are periodically updated. This time-sequential approach enables multi-grey-scale display through temporal modulation rather than spatial capacitor sizing, reducing the required device area.
4Manufacturing precision
If digital driving is implemented to reduce the influence of transistor variations, then display quality is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the compensating circuit from the pixel circuit configuration. By using a memory circuit to store digital signals and a simple drive transistor to drive the light emitting element, the complex compensating circuit is removed entirely, achieving both high display quality and low power consumption without the need for compensation components.
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 enables the display of brighter, high-resolution, multi-grey-scale images at low power consumption by reducing transistor variation effects and eliminating the need for large capacitors, while allowing for faster operation of the memory circuit and increased light emitting intensity.
Implementation Method 1
an organic EL element emits light at intensity according to the current amount
Data Source
AI summary
An electro-optical device includes scan line, data line, pixel circuit located at a position corresponding to an intersection of the scan line and the data line, a first high potential line supplies a first potential, a low potential line supplies a second potential, and a second high potential line supplies a third potential. The pixel circuit includes a light emitting element, a memory circuit disposed between the first high potential line and the low potential line, a first transistor including a gate electrically connected to the memory circuit, and a second transistor including a gate electrically connected to the scan line. The second transistor is disposed between the memory circuit and f the data line. A potential difference between the first potential and the second potential is smaller than a potential difference between the third potential and the second potential.