Amorphous Silicon Light Sensor with Compensating Unit
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Solution Overview
Problem
Conventional LCD devices face inaccuracies in adjusting brightness due to changes in ambient environment conditions, such as temperature, affecting the photocurrent generated by brightness detectors, and their complex structure makes them bulky and inefficient.
Innovation Solution
A light sensor system comprising a light-sensing unit and a compensating unit with amorphous silicon thin film transistors, where the compensating unit provides a reference current to ensure accurate brightness adjustment, and a black matrix shields the compensating unit from ambient light, allowing the light-sensing unit to accurately measure ambient light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a brightness detector is used to detect ambient light brightness, then the display brightness can be adjusted according to ambient light, but the internal element parameters of the brightness detector change due to ambient environment changes such as temperature, causing the photocurrent to not accurately reflect the brightness of ambient light
Solution Approach 1:
The patent creates a compensating unit that is a copy of the light-sensing portion with identical structure and materials. This compensating unit is shielded from light but exposed to the same temperature and environmental conditions. By copying the sensor structure and exposing it to the same environmental factors except light, the patent generates a reference photocurrent that accounts for environmental drift, thereby maintaining measurement accuracy under varying temperature conditions.
2Extent of automation
If a brightness detector with control circuit and reference values is used to adjust light source brightness, then the display brightness can be automatically adjusted, but the structure becomes complicated and bulky
Solution Approach 1:
The patent merges the brightness detection function and the environmental compensation function into a single integrated light sensor assembly. Both the light-sensing portion and the compensating unit are fabricated together on the same substrate using the same amorphous silicon TFT technology and processing steps. This integration eliminates the need for separate brightness detectors, control circuits, and reference value storage, thereby simplifying the overall structure while maintaining automatic brightness adjustment capability.
3Ease of operation
If multiple components including brightness detector, control circuit, and optical films are used in backlight module, then brightness adjustment function is achieved, but the overall structure of LCD device becomes unduly complicated and bulky
Solution Approach 1:
The patent extracts the environmental compensation function from the traditional separate control circuit and reference value system, and integrates it directly into the sensor assembly itself. By taking out the compensation functionality and embedding it within the sensor structure, the patent eliminates redundant components and reduces the overall device volume while preserving the brightness adjustment functionality.
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
This solution ensures accurate adjustment of backlight brightness based on ambient light conditions, simplifies the display device structure, and reduces bulkiness by using the same material and process for both units, maintaining accuracy across environmental changes.
Implementation Method 1
the light-sensing portion includes at least one amorphous silicon thin film transistor (TFT) configured for sensing light
Implementation Method 2
a black matrix disposed at an inner surface of the first substrate... The black matrix is configured for shielding the compensating unit from ambient light
Data Source
AI summary
An exemplary light sensor (20) includes a supporting base, a light-sensing unit (21) provided at at least one first location of the supporting base where ambient light is received, and a compensating unit (22) provided at a second location of the supporting base shielded from ambient light, the compensating unit having a structure that is the same as the light-sensing portion. The light-sensing portion includes at least one amorphous silicon thin film transistor (TFT) (210) configured for sensing light, and the compensating unit is configured for providing a reference value current for the light-sensing unit. A display device using the light sensor is also provided.