Display Panel Power Switching for Accurate Electrical Sensing
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Solution Overview
Problem
Electroluminescent display devices face reduced sensing accuracy of electrical characteristics due to sub-pixel division in time-division driving, which affects afterimage compensation performance.
Innovation Solution
A display apparatus with a power management circuit that applies different power voltages in display and sensing modes, using a high potential power voltage in the sensing mode to reduce black grayscale current and improve sensing accuracy of electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sub-pixels are driven in time-division manner to control viewing angle, then viewing angle control is achieved, but sensing accuracy of electrical characteristics deteriorates
Solution Approach 1:
The display panel is divided into multiple sub-pixels that are driven in time-division manner, with each sub-pixel having separate sensing capabilities. This segmentation allows independent sensing operations for each sub-pixel while maintaining viewing angle control through selective driving of different sub-pixel groups.
Solution Approach 2:
The display apparatus alternates between display mode and sensing mode in periodic cycles. During sensing mode, all sub-pixels are driven simultaneously with appropriate voltages to enable accurate electrical characteristic sensing, while during display mode, sub-pixels are driven in time-division manner for viewing angle control. This periodic switching resolves the contradiction by providing dedicated sensing periods.
2Adaptability or versatility
If sub-pixels are divided for time-division driving, then viewing angle control is improved, but capacitance of emitting element is reduced
Solution Approach 1:
Multiple sub-pixels are electrically connected in parallel during sensing operations, effectively merging their capacitances. This combining of capacitance resources compensates for the reduced individual capacitance of each sub-pixel, enabling accurate sensing while maintaining the time-division driving structure for viewing angle control.
3Duration of action of stationary object
If black grayscale current flows through non-sensing sub-pixels, then display continuity is maintained, but sensing accuracy is reduced
Solution Approach 1:
The harmful black grayscale current flowing through non-sensing sub-pixels is extracted and eliminated by applying zero voltage or reversed voltage to these sub-pixels during sensing mode. This removal of interfering current enables accurate sensing of the sensing sub-pixel electrical characteristics while maintaining display continuity through proper timing of sensing operations.
Solution Approach 2:
Before sensing operations begin, preliminary anti-action is applied by setting non-sensing sub-pixels to zero voltage or reversed voltage state, preventing the generation of black grayscale current that would interfere with sensing. This preemptive measure ensures sensing accuracy is not compromised by currents from non-sensing sub-pixels.
Data Source
AI summary
A display apparatus according to an example embodiment of the present disclosure comprises a display panel comprising a plurality of sub-pixels, a first power line shared by the plurality of sub-pixels, and a second power line shared by the pixels; a driver driving the display panel; a power management circuit applying a high potential power voltage to the first power line and applying a low potential power voltage to the second power line; and a sensing circuit sensing electrical characteristics of a sensing area of the display panel through the second power line to output sensing data, wherein the power management circuit applies in a display mode, a first low potential power voltage to the second power line, in a sensing mode, a second low potential power voltage higher than the first low potential power voltage to the second power line.