Display Device, Viewing Angle Control Device, And Electronic Device

• US 20080055221A1
• Filed: 09/12/2005
• Published: 03/06/2008
• Est. Priority Date: 09/17/2004
• 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: Fukushima, Hiroshi, Imai, Akira, Yabuta, Koji, Takatani, Tomoo
• Granted Patent: US 8,031,273 B2
• Time in Patent Office: Days
• US Class Current: 345/90
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0444 using a single conductive element covering the whole sensing surface, e.g. by sensing the electrical current flowing at the corners
• CPC Class Codes: G09G 2320/028 by changing the viewing angle properties, e.g. widening the viewing angle, adapting the viewing angle to the view direction
• CPC Class Codes: G09G 2320/068 for control of viewing angle adjustment
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A first transparent electrode film, which is a component of a SW-LCD for viewing angle control, is used as a touch panel. When a contacting object contacts the surface of the first transparent electrode film, a position detector detects currents flowing from plural parts of the first transparent electrode film so as to detect the contacting position of the contacting object, with reference to the detection result. With this, it is possible to provide a built-in touch sensor display device which is thin, lightweight, and low-cost, a viewing angle control device, and an electronic device.

Claims

1. :

A display device, comprising;

display switching means for electrically switching an image to be viewed, between a single image display mode and a plural image display mode; and

image display means for displaying the image,

the display switching means keeping a liquid crystal layer between a pair of substrates and including a front-side first transparent conductive film for applying a voltage to the liquid crystal layer and a back-side second transparent conductive film,

the display device further comprising position detection means for detecting, when a contacting object contacts a front surface of the display switching means, a contacting position of the contacting object by detecting currents flowing from plural parts of the first transparent conductive film.

2. :

The display device as defined in claim 1, wherein,

in the single image display mode, an image displayed by the image display means is viewable in any directions, whereas, in the plural image display mode, when viewed in a certain direction, another image overlaps the image displayed by the image display means, on account of birefringence caused by the display switching means.

3. :

The display device as defined in claim 1, wherein,

the display switching means further includes first polarizing means for outputting unidirectional linearly polarized light and second polarizing means for allowing the linearly polarized light, which has been output from the display switching means, to pass through,

in the liquid crystal layer, a longitudinal axis direction of liquid crystal molecules is always in parallel to or orthogonal to a linear polarization direction of light incident to the liquid crystal molecules, when the liquid crystal molecules are projected in a direction orthogonal to surfaces of said pair of substrates,

in the single image display mode, a longitudinal axis direction of at least some of the liquid crystal molecules is aligned to be in parallel to or orthogonal to the surfaces of said pair of substrates, and

in the plural image display mode, the longitudinal axis direction of said at least some of the liquid crystal molecules is aligned to be tilted with respect to the surfaces of said pair of substrates.

4. :

The display device as defined in claim 1, wherein,

(i) display switching by the display switching means between the single image display mode and the plural image display mode and (ii) detection of the contacting position of the contacting object by the position detection means are alternately switchable.

5. :

The display device as defined in claim 1, further comprising;

a first circuit which supplies to the first transparent conductive film a voltage or current for display switching; and

a second circuit which supplies to the first transparent conductive film a voltage or current for position detection,

a frequency of the voltage or current supplied from the first circuit to the first transparent conductive film being different from a frequency of the voltage or current supplied from the second circuit to the first transparent conductive film.

6. :

The display device as defined in claim 5, further comprising frequency detection means for obtaining only a voltage or current which has a particular frequency.

7. :

The display device as defined in claim 1, wherein,

the first transparent conductive film is divided so as to have plural regions, and a current flowing between at least two of the regions is detected by the position detection means.

8. :

The display device as defined in claim 3, wherein,

a polarization transmission axis of the first polarizing means is in parallel to a polarization transmission axis of the second polarizing means, and

the polarization transmission axes are in parallel to or orthogonal to the longitudinal axis direction of the liquid crystal molecules, when the liquid crystal molecules are projected in the direction orthogonal to the surfaces of said pair of substrates.

9. :

The display device as defined in claim 1, wherein,

the second transparent conductive film is a pattern electrode with a particular shape, and

alignment of the liquid crystal molecules in the liquid crystal layer changes at a region where a voltage or current is applied to the pattern electrode.

10. :

The display device as defined in claim 3, further comprising third polarizing means for causing unidirectional linearly polarized light to enter the image display means,

the third polarizing means being provided on one surface of the image display means, whereas the first polarizing means is provided on the other surface of the image display means,

the second polarizing means being provided on one surface of the display switching means, and

the other surface of the display switching means, on which the second polarizing means is not provided, being pasted onto the image display means.

11. :

The display device as defined in claim 1, wherein,

in the plural image display mode, a longitudinal axis direction of liquid crystal molecules forms an angle of not less than 40° and

not more than 50°

with surfaces of said pair of substrates.

13. :

An electronic device comprising the display device defined in claim 1.

14. :

An electronic device comprising the viewing angle control device defined in claim 13.

12. :

A viewing angle control device which controls a viewing angle of incident light and outputs the incident light, and which also detects a contacting position of a contacting object on a surface of a device,

the viewing angle control device comprising;

a liquid crystal element;

a linear polarization plate provided on the liquid crystal element; and

a position detection element,

the liquid crystal element including an opposing transparent electrode,

when the contacting object contacts, the position detection element detecting the contacting position of the contacting object by detecting currents flowing from plural parts of the opposing transparent electrode,

a longitudinal axis direction of liquid crystal molecules in the liquid crystal element being in parallel to a plane formed by (i) a direction of either a transmission axis or an absorption axis of the linear polarization plate and (ii) a traveling direction of light, and

the liquid crystal molecules being either;

in parallel to or orthogonal to the traveling direction of the light;

or tilted with respect to the traveling direction of the light.