OLED Photo Sensor Drive Voltage Control for Standby Power
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Solution Overview
Problem
Organic light emitting display devices continue to consume power when in power saving or stand-by modes due to continuous operation of photo sensors, leading to unnecessary energy expenditure.
Innovation Solution
An organic light emitting display device with a data driver, photo sensor, and scan driver that controls the drive voltage based on ambient light brightness, allowing the photo sensor to adjust luminance and turning off the drive voltage in power saving or stand-by modes to conserve energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the photo sensor continues to operate in power saving mode or stand-by mode, then the ambient light sensing function is maintained, but power consumption increases unnecessarily
Solution Approach 1:
The photo sensor's operation is made dynamic by switching between active and inactive states based on the display device's operating mode. The control unit activates the photo sensor only during normal display operation and deactivates it during power saving mode or stand-by mode, allowing the system to adapt its power consumption to actual operational needs while maintaining sensing capability when required
Solution Approach 2:
The photo sensor operates periodically rather than continuously, being activated only during normal display mode and deactivated during power saving or stand-by modes. This periodic operation pattern reduces overall power consumption while ensuring the ambient light sensing function is available whenever the display is actively showing content
2Adaptability or versatility
If the drive voltage is controlled on during normal mode, then the photo sensor can adjust luminance according to ambient light, but power consumption increases when not needed
Solution Approach 1:
The drive voltage to the photo sensor is dynamically controlled based on the display device's operational state. The control unit applies drive voltage during normal mode to enable luminance adjustment according to ambient light conditions, and removes the drive voltage during power saving mode or stand-by mode to eliminate unnecessary power consumption while preserving the adaptability function when needed
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 solution effectively reduces power consumption by controlling the photo sensor's operation based on the device's mode, enhancing the visible angle and reducing power usage during non-normal operating conditions.
Implementation Method 1
The photo sensor is adapted to: sense a brightness of an ambient light to determine a sensed brightness of the ambient light
Implementation Method 2
The pixel portion is adapted to: receive the data signal and the scan signal; receive the brightness signal; and display an image having a luminance indicative of the brightness signal
Data Source
AI summary
An organic light emitting display device and a driving method for the same is provided. The device includes a pixel portion adapted to receive a scan signal and a data signal and display an image. A scan driver generates and applies the scan signal to the pixel portion. A data driver generates and applies the data signal and a pixel voltage to the pixel portion. When the device is operating in the normal mode, the data driver also applies a drive voltage to a photo sensor also included in the display device. The photo sensor adjusts a luminance of the pixel portion according to a sensed brightness of ambient light. When the device is operating in the power saving or stand-by mode, the data driver controls the drive voltage off and thereby prevents power consumption by the photo sensor.