Area Sensor with Visible and Infrared Light Sensors for Illuminance Adaptation
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Solution Overview
Problem
Conventional liquid crystal display devices with integrated touch panels using light sensor elements face challenges in recognizing images due to ambient brightness, as different light sensor elements with varying sensitivities struggle to detect positions accurately in wide ranges of environmental illuminance, leading to limited usability.
Innovation Solution
An area sensor system incorporating both visible light sensors and infrared light sensors, with a light-emitting section that irradiates the position detecting section with infrared light, allowing for separate image detection and position recognition across a broader range of environmental illuminances by switching between sensor types based on ambient light intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple types of light sensor elements with different light sensitivities are used, then optical information input capability is improved in both strong and weak outside light conditions, but the range of environmental illuminances where accurate image reading is possible remains limited
Solution Approach 1:
The sensor array is segmented into different types of light sensor elements (first type with first sensitivity and second type with second sensitivity) that are spatially distributed across the detector surface. This segmentation allows different regions to specialize in detecting different light intensity ranges, resolving the contradiction between adaptability and reliability.
Solution Approach 2:
Different regions of the detector surface are assigned different local qualities through the use of light sensor elements with different sensitivities. The first type of light sensor elements are optimized for certain illuminance conditions while the second type is optimized for other conditions, allowing the system to maintain reliable image reading across a wide range of environmental illuminances.
2Ease of operation
If light sensor elements are used to detect position through reflected light, then touch panel function is achieved, but image recognition becomes difficult under varying ambient brightness conditions
Solution Approach 1:
The system changes the parameter of light sensitivity by employing multiple types of light sensor elements with different sensitivities. This allows the sensor array to adapt to varying ambient brightness conditions while maintaining both touch panel functionality and image recognition accuracy across different illuminance environments.
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
Enables accurate position detection in a wider range of environmental illuminances by utilizing visible light sensors in bright conditions and infrared light sensors in low-light conditions, reducing circuit complexity and power consumption while maintaining image recognition capabilities.
Implementation Method 1
light sensor elements that detect the intensity of received visible light and infrared light sensors each containing light sensor elements that detect the intensity of received infrared light
Implementation Method 2
a light-emitting section for irradiating the position detecting section with light containing infrared light from behind
Data Source
AI summary
A liquid crystal display device of the present invention includes a liquid crystal panel (20) having an area sensor function of detecting the position of an input from an outside source by detecting an image on a panel surface. The liquid crystal panel (20) (position detecting section), provided with visible light sensors (31A) each containing light sensor elements (30) that detect the intensity of received visible light and infrared light sensors (31B) each containing light sensor elements (30) that detect the intensity of received infrared light, which detects an input position by the visible light sensors (31A) and the infrared light sensors (31B) separately detecting an image on the detector surface. The liquid crystal display device further includes a backlight (light-emitting section) for irradiating the liquid crystal panel (20) with light containing infrared light. This achieves an area sensor capable of accurate position detection in a wide range of environmental illuminances and a liquid crystal display device equipped with such an area sensor.