Stretchable Display Compensation Circuit for Luminance Uniformity
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Solution Overview
Problem
Stretchable displays experience luminance reduction and luminance unevenness due to changes in pixel area and transistor characteristics when the display panel size changes, necessitating a circuit configuration to compensate for these issues.
Innovation Solution
A compensation circuit for stretchable displays that uses a strain sensor to control current flow through light emitting devices, incorporating a capacitive-type strain sensor with a flexible insulating film and a circuit structure that includes storage capacitors and TFTs to compensate for both luminance and threshold voltage changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display panel is stretched to increase its area, then the display coverage is improved, but the luminance of the light emitting device decreases
Solution Approach 1:
The patent employs a feedback mechanism where the drain voltage of the driving TFT is sensed and fed back to adjust the gate voltage. This feedback loop compensates for luminance reduction by dynamically adjusting the driving voltage based on the actual luminance output, ensuring stable brightness even when the display panel is stretched and pixel area changes
Solution Approach 2:
The patent changes the electrical parameters (voltage levels) of the driving TFT to compensate for physical changes in the display panel. By adjusting the gate voltage and drain voltage parameters in response to stretching, the system maintains constant luminance despite changes in pixel area and transistor characteristics
2Area of stationary object
If the display panel is stretched, then the display area increases, but luminance unevenness occurs due to changes in TFT characteristics
Solution Approach 1:
The feedback circuit senses drain voltage variations that indicate luminance unevenness and adjusts gate voltages accordingly. This real-time feedback compensation corrects for TFT characteristic changes caused by stretching, maintaining uniform luminance across the display panel
Solution Approach 2:
The patent performs preliminary compensation by pre-adjusting the gate voltage based on expected TFT characteristic changes during stretching. The circuit is designed to anticipate and counteract luminance unevenness before it fully manifests, maintaining uniformity proactively
3Illumination intensity
If a compensation circuit is added to maintain luminance, then luminance stability is improved, but the device complexity increases
Solution Approach 1:
The driving TFT serves multiple functions: it drives the light emitting device and simultaneously acts as a sensing element for luminance feedback. The gate electrode structure is designed to perform both driving and compensation functions, reducing the need for separate dedicated compensation components and simplifying the overall circuit
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 compensation circuit effectively maintains display luminance and compensates for threshold voltage changes during stretching, facilitating the commercialization of stretchable displays by ensuring even luminance without additional components.
Implementation Method 1
the strain sensor may be a capacitive type, and may be a sandwich structure equipped with a flexible insulating film between two electrodes
Data Source
AI summary
The present invention relates to a micro LED driving circuit comprising a double gate transistor, and comprises: a PWM circuit unit for adjusting the light emission time of a micro LED; and a CCG circuit unit for controlling, on the basis of PWM data voltage, that a certain current is supplied during light emission of the micro LED.