Photo Sensor Circuit for Flat Panel Display Luminance Control
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Solution Overview
Problem
Existing photo sensors used in flat panel displays face challenges with low power output, making it difficult to effectively control image luminance based on ambient light, leading to inefficient power consumption and visibility issues.
Innovation Solution
A photo sensor design incorporating transistors, a photo diode, and capacitors that amplify the light sensing signal to control image luminance, including a specific configuration of transistors and capacitors to enhance power output and dynamic range, allowing for stable operation and improved luminance adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a photo sensor is installed inside a panel of a flat panel display device, then the luminance of the displayed image can be controlled according to ambient light, but the photo sensor produces low power output making it difficult to effectively control image luminance
Solution Approach 1:
The patent combines multiple transistors (first through seventh transistors) and capacitors with the photo diode to form an integrated photo sensor circuit. This merging of components allows the circuit to amplify the weak signal from the photo diode, transforming the low power output limitation into sufficient driving capability for luminance control while maintaining the ambient light sensing function.
Solution Approach 2:
The patent introduces intermediate signal processing components (transistors and capacitors) between the photo diode and the luminance control system. These intermediaries amplify and condition the photo diode's output signal, enabling effective luminance control despite the photo sensor's inherently low power output when installed inside the panel.
2Illumination intensity
If the luminance of the displayed image is increased to improve visibility in high ambient light, then visibility improves, but power consumption increases unnecessarily
Solution Approach 1:
The patent implements a feedback mechanism where the photo sensor continuously monitors ambient light conditions and automatically adjusts the displayed image luminance accordingly. This feedback loop ensures visibility is optimized for current lighting conditions without unnecessary power consumption, as the system only increases luminance when ambient light detection indicates it is needed.
Solution Approach 2:
The patent makes the display luminance dynamic by linking it to real-time ambient light detection. The luminance adjusts automatically based on detected light conditions, allowing the display to consume minimal power in dark environments while providing high visibility in bright environments, thus resolving the contradiction between visibility and power consumption.
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 enhanced photo sensor effectively amplifies the light sensing signal, enabling better control of image luminance in response to ambient light, reducing power consumption and improving visibility across varying light conditions.
Implementation Method 1
a photo diode having a cathode electrode coupled to a third power source and an anode electrode coupled to a fourth node
Data Source
AI summary
A photo sensor in a flat panel display includes a first transistor having first, second, and gate electrodes respectively coupled to first, second, and third nodes; a second transistor having first, second, and gate electrodes, respectively coupled to a fourth node, the first node, and a first control signal line; a third transistor having first, second, and gate electrodes, respectively coupled to the second node, the third node, and the first control signal line; a fourth transistor having first, second, and gate electrodes, respectively coupled to a reset power line, the third node, and a reset signal line; a fifth transistor having first, second, and gate electrodes, respectively coupled to a first power source, the first node, and a second control signal line; a sixth transistor having first, second, and gate electrodes, respectively coupled to the second node, output line, and the second control signal line; and a seventh transistor.