Area sensor and liquid crystal display device with area sensor
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 ( 31 A) each containing light sensor elements ( 30 ) that detect the intensity of received visible light and infrared light sensors ( 31 B) each containing light sensor elements ( 30 ) that detect the intensity of received infrared light, which detects an input position by the visible light sensors ( 31 A) and the infrared light sensors ( 31 B) 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.
1. An area sensor for detecting the position of an input from an outside source by detecting an image on a detector surface, the area sensor comprising:
a position detecting section comprising visible light sensors each comprising light sensor elements that detect the intensity of received visible light and infrared light sensors each comprising light sensor elements that detect the intensity of received infrared light, the position detection section being configured to detect an input position by the visible light sensors and the infrared light sensors separately detecting an image on the detector surface; and
a light-emitting section configured to irradiate the position detecting section with light containing infrared light from behind;
wherein the light sensor elements comprising each of the infrared light sensors are each comprise an optical filter configured to block visible light; and
wherein the optical filter comprises a laminated structure comprising a red color filter and a blue color filter.
2. The area sensor as set forth in claim 1 , wherein:
if the intensity of infrared rays in an environment where the area sensor is placed is greater than or equal to a predetermined value, the position detecting section carries out position detection by using the visible light sensors; and
if the intensity of infrared rays in an environment where the area sensor is placed is less than the predetermined value, the position detecting section carries out position detection by using the infrared light sensors.
3. The area sensor as set forth in claim 2 , wherein the predetermined value of intensity of infrared light falls within a range of 1.00 to 1.80 mW/cm 2 , based on the integrated radiant intensity of light at wavelengths of 800 to 1,000 nm.
4. The area sensor as set forth in claim 1 , further comprising:
a light intensity sensor configured to measure the intensity of infrared rays in an environment where the area sensor is placed; and
a sensor switching section which, if the intensity of infrared rays measured by the light intensity sensor is greater than or equal to a predetermined value, is configured to use information obtained from the visible light sensors as position information and which, if the intensity of infrared rays measured by the light intensity sensor is less than the predetermined value, is configured to use information obtained from the infrared light sensors as position information.
5. The area sensor as set forth in claim 4 , wherein the predetermined value of intensity of infrared light falls within a range of 1.00 to 1.80 mW/cm 2 , based on the integrated radiant intensity of light at wavelengths of 800 to 1,000 nm.
6. The area sensor as set forth in claim 1 , wherein:
if the illuminance of an environment where the area sensor is placed is greater than or equal to a predetermined value, the position detecting section carries out position detection by using the visible light sensors; and
if the illuminance of an environment where the area sensor is placed is less than the predetermined value, the position detecting section carried out position detection by using the infrared light sensors.
7. The area sensor as set forth in claim 1 , further comprising:
an illuminance sensor configured to measure the illuminance of an environment where the area sensor is placed; and
a sensor switching section which, if the illuminance measured by the illuminance sensor is greater than or equal to a predetermined value, is configured to use information obtained from the visible light sensors as position information and which, if the illuminance measured by the illuminance sensor is less than the predetermined value, is configured to use information obtained from the infrared light sensors as position information.
8. The area sensor as set forth in claim 1 , wherein:
the visible light sensors and the infrared light sensors are disposed in rows and columns in a matrix pattern; and
the visible light sensors and the infrared light sensors are disposed alternately in a checkered pattern.
9. The area sensor as set forth in claim 8 , wherein:
the visible light sensors and the infrared light sensors are disposed in rows and columns in a matrix pattern; and
the visible light sensors and the infrared light sensors are disposed alternately in a checkered pattern.
10. A liquid crystal display device comprising a liquid crystal panel comprising an area sensor as set forth in claim 1 .
11. An area sensor for detecting the position of an input from an outside source by detecting an image on a detector surface, the area sensor comprising:
a position detecting section comprising visible light sensors each comprising light sensor elements that detect the intensity of received visible light and infrared light sensors each comprising light sensor elements that detect the intensity of received infrared light, the position detecting section being configured to detect an input position by the visible light sensors and the infrared light sensors separately detecting an image on the detector surface;
a light-emitting section configured to irradiate the position detecting section with light containing infrared light from behind;
wherein if the intensity of infrared rays in an environment where the area sensor is placed is greater than or equal to a predetermined value, the position detecting section carries out position detection by using the visible light sensors; and
if the intensity of infrared rays in an environment where the area sensor is placed is less than the predetermined value, the position detecting section carries out position detection by using the infrared light sensors.
12. The area sensor as set forth in claim 11 , wherein the light sensor elements comprising each of the infrared light sensors each comprise an optical filter for blocking visible light.
13. The area sensor as set forth in claim 12 , wherein the optical filter comprises a mixture of a red pigment, a green pigment, and a blue pigment.
14. The area sensor as set forth in claim 11 , wherein:
the visible light sensors and the infrared light sensors are disposed in rows and columns in a matrix pattern; and
the visible light sensors and the infrared light sensors are disposed alternately in a checkered pattern.
15. A liquid crystal display device comprising a liquid crystal panel comprising an area sensor as set forth in claim 11 .
16. An area sensor for detecting the position of an input from an outside source by detecting an image on a detector surface, the area sensor comprising:
a position detecting section comprising visible light sensors each comprising light sensor elements that detect the intensity of received visible light and infrared light sensors each comprising light sensor elements that detect the intensity of received infrared light, the position detection section being configured to detect an input position by the visible light sensors and the infrared light sensors separately detecting an image on the detector surface; and
a light-emitting section configured to irradiate the position detecting section with light containing infrared light from behind;
an illuminance sensor configured to measure the illuminance of an environment where the area sensor is placed; and
a sensor switching section which, if the illuminance measured by the illuminance sensor is greater than or equal to a predetermined value, is configured to use information obtained from the visible light sensors as position information and which, if the illuminance measured by the illuminance sensor is less than the predetermined value, is configured to use information obtained from the infrared light sensors as position information.
17. The area sensor as set forth in claim 16 , wherein the light sensor elements comprises each of the infrared light sensors each comprise an optical filter for blocking visible light.
18. The area sensor as set forth in claim 17 , wherein the optical filter comprises a mixture of a red pigment, a green pigment, and a blue pigment.
19. A liquid crystal display device comprising a liquid crystal panel comprising an area sensor as set forth in claim 16 .