Dual Optical Sensor Display Device Illuminance Adaptation
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Solution Overview
Problem
As screen size and resolution of active matrix display devices increase, they face issues with power consumption and display quality due to increased wiring resistance and parasitic capacitance, as well as variations in ambient illuminance and color temperature, which affect the performance of existing optical sensors.
Innovation Solution
A display device utilizing an amorphous thin film optical sensor with high sensitivity to visible light and a polycrystalline thin film optical sensor with lower sensitivity to visible light but infrared sensitivity, which adjusts luminance and color tone based on detected illuminance and color temperature, and includes a switching transistor to optimize power usage and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single optical sensor is used for illuminance detection, then the device complexity is reduced, but the measurement precision deteriorates at different illuminance levels
Solution Approach 1:
The optical sensing function is segmented into two distinct sensors: a first optical sensor optimized for low illuminance detection and a second optical sensor optimized for high illuminance detection. Each sensor is tailored to specific illuminance ranges, allowing precise measurement across the full spectrum without requiring a single complex sensor to handle all conditions.
Solution Approach 2:
The patent changes the optical parameters of the sensors by using different optical sensitivities for the first and second optical sensors. The first sensor has higher sensitivity for low light conditions, while the second sensor has lower sensitivity to avoid saturation in bright conditions. This parameter differentiation enables accurate detection across varying illuminance levels.
2Reliability
If the optical sensor operates continuously to detect ambient conditions, then the display quality is maintained, but the power consumption increases
Solution Approach 1:
The control device periodically determines whether to switch between the first and second optical sensors based on detected illuminance levels, rather than operating a single sensor continuously. This periodic switching strategy maintains display quality by ensuring appropriate sensor activation while reducing overall power consumption by keeping sensors in low-power states when not actively detecting.
Solution Approach 2:
The patent extracts the illuminance detection function from a single continuous-operating sensor and separates it into two sensors that are activated only when needed for specific illuminance ranges. This extraction allows the system to maintain reliability by having dedicated sensors for different conditions while reducing power consumption by not continuously operating both sensors at full capacity.
3Measurement precision
If the display device uses higher sensitivity optical sensor for low illuminance, then the detection capability at low light is improved, but the output becomes saturated at high illuminance
Solution Approach 1:
The optical detection range is segmented into two distinct operational zones: low illuminance detection handled by the first optical sensor with high sensitivity, and high illuminance detection handled by the second optical sensor with lower sensitivity. This segmentation allows each sensor to operate within its optimal range without saturation, expanding the overall adaptability of the system across different lighting conditions.
Solution Approach 2:
The patent changes the sensitivity parameter of the optical sensors by using two different sensitivity levels. The first sensor uses high sensitivity for low illuminance detection, while the second sensor uses lower sensitivity to prevent saturation at high illuminance levels. This parameter variation enables the system to maintain measurement precision across the full illuminance spectrum.
4Adaptability or versatility
If the display device uses lower sensitivity optical sensor for high illuminance, then the saturation issue is reduced, but the detection capability at low illuminance deteriorates
Solution Approach 1:
The patent segments the optical sensing responsibilities by assigning low illuminance detection to the first optical sensor and high illuminance detection to the second optical sensor. This segmentation ensures that the lower sensitivity sensor (second sensor) is not used for low illuminance detection, thereby preserving detection capability at low light levels while maintaining adaptability for high illuminance conditions.
Solution Approach 2:
The system changes the sensitivity parameter assignment by using the first optical sensor with high sensitivity for low illuminance and the second optical sensor with lower sensitivity for high illuminance. This parameter differentiation resolves the contradiction by ensuring each sensor operates in its optimal sensitivity range, maintaining both measurement precision and adaptability.
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 reduces power consumption and enhances display quality by accurately detecting ambient conditions and adjusting the display image accordingly, maintaining optimal performance across varying illuminance and temperature ranges.
Implementation Method 1
an amorphous thin film optical sensor 391 having high optical sensitivity to visible light
Implementation Method 2
a polycrystalline thin film optical sensor 392 having lower optical sensitivity to visible light than the amorphous thin film optical sensor 391 but also having optical sensitivity to infrared light
Data Source
AI summary
An object is to provide a display device with low power consumption and good display quality. A first substrate is provided with a terminal portion, a pixel electrode, a switching transistor including an oxide semiconductor, a first optical sensor having high optical sensitivity to visible light, and a second optical sensor having optical sensitivity to infrared light and having lower optical sensitivity to visible light than the first optical sensor. The illuminance or color temperature around a display device is detected using the first and second optical sensors, and the luminance or color tone of a display image is adjusted. A second substrate is provided so as to face the first substrate, and is provided with a counter electrode. In a period for displaying a still image, the switching transistor is turned off so that the counter electrode is brought into a floating state.