Common Cathode Display Driving With Variable Off-Voltage
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Solution Overview
Problem
Existing display apparatuses, particularly those with light emitting devices, face challenges in reducing power consumption and improving luminous efficiency while maintaining a simplified structure.
Innovation Solution
The display apparatus integrates a pixel driving circuit on a substrate, utilizing a variable cathode-off voltage and a simplified structure to reduce power consumption and enhance driving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light emitting device is used to achieve faster lighting speed and higher luminance, then display performance is improved, but power consumption increases
Solution Approach 1:
The cathode voltage is made dynamically variable between two states: a first cathode voltage (cathode-on) during light emission and a second cathode voltage (cathode-off) during non-emission. This dynamic voltage switching allows the light emitting device to operate efficiently by adjusting the voltage according to the emission state, reducing power consumption while maintaining high luminance during active display periods
Solution Approach 2:
The patent changes the voltage parameter of the cathode electrode based on the emission state. By switching between a first cathode voltage (higher) for light emission and a second cathode voltage (lower or zero) for non-emission, the system optimizes the balance between achieving high luminance when needed and reducing power consumption during static or dark periods
2Speed
If pixel circuits are directly formed on the substrate to improve driving efficiency, then response speed is improved, but device complexity increases
Solution Approach 1:
The display device is segmented into independent light emitting devices with individually controllable electrodes. Each light emitting device can be controlled separately by the pixel driving circuit, allowing for precise and rapid control of individual pixels while maintaining a relatively simple overall structure through modular design
Solution Approach 2:
The common cathode electrode structure serves multiple functions: it acts as the cathode for light emission, provides a reference voltage level, and enables simplified voltage control for multiple light emitting devices simultaneously. This multi-functionality reduces the need for separate control structures for each device, thereby reducing overall complexity while maintaining fast response capability
Data Source
AI summary
A display apparatus comprises a substrate including a display area and a non-display area, a pixel driving circuit at the display area on the substrate, an insulating layer over the pixel driving circuit, a plurality of light emitting devices spaced apart from each other over the insulating layer and electrically connected to the pixel driving circuit, and a plurality of common cathode electrodes electrically connected to the plurality of light emitting devices and receiving a cathode voltage. The cathode voltage has a cathode-on voltage or a cathode-off voltage, and the cathode-off voltage is variable.