DISPLAY DEVICE HAVING OPTICAL SENSORS

• US 20110007047A1
• Filed: 02/16/2009
• Published: 01/13/2011
• Est. Priority Date: 03/03/2008
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kubota, Akinori, Gotoh, Toshimitsu, Uehata, Masaki, Fujioka, Akizumi
• Granted Patent: US 8,416,227 B2
• Time in Patent Office: Days
• US Class Current: 345/207
• CPC Class Codes: G02F 1/13312 Circuits comprising photodetectors for purposes other than feedback
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133509 Filters, e.g. light shielding masks
• CPC Class Codes: G02F 2203/11 involving infrared radiation

Abstract

A liquid crystal panel with built-in sensors 11 includes, in a pixel array 17, a plurality of pixel circuits 1 and a plurality of optical sensors 2 which are arranged two-dimensionally. Infrared light transmitting filters 3 that allow infrared light to pass therethrough and cut off visible light are provided in respective paths of light entering the optical sensors 2. A backlight 15 including white LEDs 4 and infrared LEDs 5 is provided on a back surface of the liquid crystal panel 11. With this, reflected light of backlight light including infrared light is detected by the optical sensors 2 without receiving the influence of visible light, and thus a touch position is detected with high accuracy, irrespective of display data.

Claims

1. A display device including a plurality of optical sensors, the display device comprising:

a display panel including a plurality of pixel circuits and a plurality of optical sensors which are arranged two-dimensionally;

filter portions that are provided in respective paths of light entering the optical sensors and that allow infrared light to pass therethrough and cut off visible light; and

a backlight that is provided on a back surface side of the display panel and that emits at least light passing through the filter portions.

2. The display device according to claim 1, wherein

the pixel circuits and the optical sensors are formed of polysilicon, and

the backlight emits infrared light with a shorter wavelength than a fundamental absorption edge wavelength of silicon.

3. The display device according to claim 1, wherein the backlight emits infrared light having a peak wavelength in an absorption spectrum of an atmosphere.

4. The display device according to claim 3, wherein the backlight emits infrared light having a peak wavelength in a range of 850 nm to 960 nm.

5. The display device according to claim 1, wherein

the backlight includes a first luminous element that emits visible light;

a second luminous element that emits infrared light;

a light guide plate; and

a reflection sheet that is provided on one surface of the light guide plate and that allows infrared light to pass therethrough and reflects visible light,

the first luminous element is arranged along a side surface of the light guide plate, and

the second luminous element is arranged on a side of the surface of the light guide plate where the reflection sheet is provided.

6. The display device according to claim 1, wherein

the backlight includes a first luminous element that emits visible light;

and a second luminous element that emits infrared light, and

the first and second luminous elements are arranged on a same substrate or are enclosed in a same package.

7. The display device according to claim 1, wherein the backlight includes, as a light source, only a luminous element that emits infrared light.

8. The display device according to claim 1, wherein

the filter portions have a pass band suitable for infrared light emitted from the backlight, and

each of the optical sensors is arranged in a position in which the optical sensor overlaps a corresponding filter portion when viewed in a direction perpendicular to the pixel circuits.

9. The display device according to claim 8, wherein the filter portions have a pass band having an upper limit and a lower limit suitable for infrared light emitted from the backlight.

10. The display device according to claim 1, wherein the display panel further includes a filter that allows visible light to pass therethrough and cuts off light with longer wavelengths than infrared light emitted from the backlight.

11. The display device according to claim 1, wherein the display panel further includes a filter whose pass band includes all or part of a visible light range and a wavelength range of infrared light emitted from the backlight.