JP2007279819A - Display device with touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce slippage of a touch position resulted from difference in the visual line direction of a user. <P>SOLUTION: A curved touch panel 13 of a capacitance type touch panel has a curved face-like touch surface T and a light scattering layer on the back surface. An LED 11 and a liquid crystal panel 12 project an image onto the back surface of the curved face touch panel 13. The user touches the touch surface T of the curved face touch panel 13 while viewing the projected image. The light scattering layer can be provided, for example, by applying a coating material containing a white pigment onto the back surface of a curved substrate 14; roughing the back surface of the curved substrate 14 by sand blasting or the like; forming the curved substrate 14 by a translucent glass or the like; providing a translucent screen member 18 on the back surface of the curved substrate 14; or the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device with a touch panel, and more particularly to a display device including a touch panel having a curved touch surface.

  In an in-vehicle electronic device, a game device, and the like, it has been proposed to use a touch panel having a curved touch surface (hereinafter referred to as a curved touch panel) in order to improve the operability of the device. However, for displays used with curved touch panels, at present, even cylindrical surface (arch-shaped) displays obtained by curving flexible flat displays are still in the development stage, and spherical (dome-shaped) ) And any curved surface display will take more time. Therefore, practically, it is considered that there are many forms in which a curved touch panel is used with a flat display.

  FIG. 6 is a diagram illustrating an appearance of a display device with a touch panel including a curved touch panel and a flat display. In FIG. 6, a curved touch panel 1 is a transparent touch panel having a hemispherical touch surface. Below the curved touch panel 1, a display device (for example, a liquid crystal display device) that displays a flat display screen 2 in a space formed by the curved touch panel 1 is provided.

As a technique related to the present invention, Patent Document 1 discloses a coordinate input device including a touch panel with a hemispherical or dome-shaped contact portion. Patent Document 2 discloses an electro-optical panel having a curved touch panel.
JP 2004-94450 A JP 2004-252676 A

  However, the display device with a touch panel shown in FIG. 6 has a problem that the touch position is shifted depending on the direction in which the user views the display device because the curved touch panel 1 is separated from the display screen 2. For example, consider the case where the user touches a point P in the display screen 2 in FIG. The user U1 who sees the point P from directly above the curved touch panel 1 touches the point Q1 located on the top of the curved touch panel 1 in an attempt to touch the point P. On the other hand, the user U2 who sees the point P obliquely touches the point Q2 at a position away from the top of the curved touch panel 1 in an attempt to touch the point P. Thus, if there is a position shift (parallax) caused by the difference in the line-of-sight direction, the touch position is shifted and the input from the user cannot be detected correctly.

  Therefore, an object of the present invention is to provide a display device with a curved touch panel in which a shift in a touch position caused by a difference in line-of-sight direction is reduced.

The first invention is a display device with a touch panel,
A capacitive touch panel having a curved touch surface and a light scattering layer on the back;
An image projection unit that projects an image on the back surface of the touch panel.

According to a second invention, in the first invention,
The touch panel includes a curved substrate formed of a light-transmitting material and having a light-scattering coating applied on the back surface.

According to a third invention, in the first invention,
The touch panel includes a curved substrate that is formed of a light-transmitting material and is roughened on a back surface.

According to a fourth invention, in the first invention,
The touch panel includes a curved substrate formed of a light scattering material.

According to a fifth invention, in the first invention,
The touch panel includes a curved substrate formed of a light transmissive material,
It is characterized by further comprising a screen member made of a material having light scattering properties and disposed along the back surface of the curved substrate.

According to a sixth invention, in the first invention,
The image projection unit includes a light source and a non-light emitting display panel,
The light emitted from the light source is directly projected on the back surface of the touch panel after being transmitted or reflected by the display panel.

According to a seventh invention, in the first invention,
The image projection unit includes a light source, a non-luminous display panel, and a projection lens.
The light emitted from the light source is transmitted or reflected by the display panel and then projected on the back surface of the touch panel by the projection lens.

In an eighth aspect based on the first aspect,
The image projection unit includes a self-luminous display panel and a projection lens,
The light emitted from the display panel is projected onto the back surface of the touch panel by the projection lens.

  According to the first aspect, since the light scattering layer is provided on the back surface of the touch panel, the user can see the image projected on the back surface of the touch panel. Therefore, the user can correctly touch the point on the curved touch panel corresponding to the point to be touched on the display screen while viewing the projected image from any direction. As described above, according to the first aspect, it is possible to reduce the position shift (parallax) due to the difference in the line-of-sight direction and to reduce the touch position shift.

  According to the second to fifth aspects of the present invention, it is possible to obtain a display device with a touch panel in which a light scattering layer is provided on the back surface of the touch panel to reduce touch position deviation.

  According to the sixth aspect of the invention, it is possible to obtain a display device with a touch panel that uses a non-light emitting display panel and reduces the displacement of the touch position with a small number of optical components.

  According to the seventh or eighth invention, it is possible to obtain a display device with a touch panel in which a shift in touch position is reduced by using a non-light emitting display panel or a self light emitting display panel. In addition, since the projection lens is provided, blurring of an image projected on the touch panel can be reduced even when the projection magnification is large.

(First embodiment)
FIG. 1 is a diagram showing a configuration of a display device with a touch panel according to the first embodiment of the present invention. A display device 10 illustrated in FIG. 1 includes a light emitting diode (hereinafter abbreviated as LED) 11, a liquid crystal panel 12, and a curved touch panel 13.

  The curved touch panel 13 is a capacitive touch panel having a curved touch surface T. FIG. 2 is a cross-sectional view showing the basic structure of the curved touch panel 13. As shown in FIG. 2, the curved touch panel 13 is formed by sequentially laminating a transparent conductive film 15 and a protective film 16 on a curved curved substrate 14 formed in a convex shape. In the curved touch panel 13, the surface on which the transparent conductive film 15 and the protective film 16 are formed becomes the touch surface T. Hereinafter, the back surface (surface S in FIG. 2) of the touch surface T is referred to as “rear surface”.

  The curved substrate 14 is a hemispherical (dome-shaped) substrate having a thickness of about 1 to 2 mm. The curved substrate 14 is made of, for example, soda glass, borosilicate glass, heat resistant glass, or the like. Alternatively, the curved substrate 14 may be formed of a plastic material that can withstand a film forming process described later. The shape of the curved substrate 14 is not limited to a hemispherical shape, and may be a convex surface, a concave surface, or an arbitrary relief-shaped uneven surface (for example, the shape of the face of a person or a cartoon character).

The transparent conductive film 15 is a transparent film formed of a conductive material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or SnO ₂ . The transparent conductive film 15 is formed on the curved substrate 14 by a sputtering process. The film thickness of the transparent conductive film 15 is about 10 nm to 20 nm, and the surface resistance of the transparent conductive film 15 is about 1 KΩ / □.

  Note that the transparent conductive film 15 is not necessarily a single continuous film. For example, when the shape of the curved substrate 14 is complicated, the curved substrate 14 is divided into a plurality of regions, a film matching the shape of the region is attached to each region, and the attached films are electrically connected by wiring. May be.

The protective film 16 is a transparent film formed of an insulating material such as SiO ₂ , SiNx, or transparent resin. The protective film 16 is formed on the transparent conductive film 15 by sputtering, CVD (Chemical Vapor Deposition), or coating. The thickness of the protective film 16 is about 100 nm to 1 μm.

  A plurality of lead wires (not shown) are connected to the transparent conductive film 15 for current detection. A position calculation unit (not shown) that calculates a two-dimensional position on the curved touch panel 13 based on the detected current is connected to the lead wire. In order to correctly calculate the two-dimensional position on the curved touch panel 13 in the position calculation unit, it is necessary to provide three or more lead wires on the outer peripheral portion of the curved substrate 14.

  By the way, there are other types of touch panels such as a resistance film method, an electromagnetic induction method, an optical method, and an ultrasonic method in addition to the capacitance method. However, methods other than the capacitive method are not suitable for the curved touch panel 13. The reason is as follows.

  In the resistance film method, it is necessary to hold two substrates on which a resistance film is formed with a slight gap therebetween. However, when the shape of the substrate is a spherical surface or an arbitrary curved surface, it is extremely difficult to adjust the distance between the two substrates to the target value with high accuracy. In the electromagnetic induction method, it is necessary to dispose an opaque sensor substrate on the back surface of the display element. However, when the sensor substrate is arranged at such a position, the sensor sensitivity is lowered. In addition to this, the electromagnetic induction method also has a problem that it is difficult to determine how close the pen is to be touched. Regarding the optical type, it is impossible in principle to detect a touch along a curved surface in consideration of the straightness of light. The ultrasonic method has a problem that it is difficult to manufacture a fine ultrasonic transducer (transmitting / receiving element) on a curved surface.

  Unlike these four methods, the capacitance method has relatively few manufacturing problems even if the substrate has a spherical shape or an arbitrary curved surface. For this reason, the curved touch panel 13 of the present embodiment employs a capacitance method that is more advantageous than the above four methods.

  A light scattering layer is provided on the back surface of the curved touch panel 13 having the basic structure shown in FIG. A method of providing a light scattering layer on the back surface of the curved touch panel 13 will be described with reference to FIG. As a first method, the curved substrate 14 is formed of a light transmissive material (for example, transparent glass or transparent plastic), and the back surface of the curved substrate 14 (the surface serving as the back surface of the curved touch panel 13) has light scattering properties. There is a method of applying a paint (see FIG. 3A). Specifically, a paint containing a white pigment may be spray-coated on the back surface of the curved substrate 14. Thereby, as shown to Fig.3 (a), the light-scattering layer 17 by a coating material can be provided in the back surface of the curved-surface touch panel 13. FIG.

  As a second method, there is a method in which the curved substrate 14 is formed of a light-transmitting material, and a roughening process is performed on the back surface of the curved substrate 14 (see FIG. 3B). Specifically, a sandblasting process or a hydrofluoric acid etching process may be performed on the back surface of the curved substrate 14 as a roughening process. As a result, as shown in FIG. 3B, the back surface portion (the portion with the dot pattern) of the curved substrate 14 can have light scattering properties, and the light scattering layer can be provided on the back surface of the curved touch panel 13.

  As a third method, there is a method of forming the curved substrate 14 with a material having a light scattering property (see FIG. 3C). Specifically, the curved substrate 14 may be formed of milky white glass or translucent plastic. As a result, as shown in FIG. 3C, the entire curved substrate 14 (part with a dotted pattern) can have light scattering properties, and a light scattering layer can be provided on the back surface of the curved touch panel 13.

  As a fourth method, the curved substrate 14 is formed of a light-transmitting material, and the screen member 18 is formed of a light-scattering material separately from this, and the screen member 18 is moved along the back surface of the curved substrate 14. There is a method of providing (see FIG. 3D). Specifically, a semitransparent sheet may be attached to the back surface of the curved substrate 14 as the screen member 18. Alternatively, the thin screen member 18 having the same shape as the back surface of the curved substrate 14 may be formed of translucent plastic, and the formed screen member 18 may be installed along the back surface of the curved substrate 14. Thereby, as shown in FIG.3 (d), the light-scattering layer which consists of the screen member 18 can be provided in the back surface of the curved-surface touch panel 13. FIG.

  In each of the above methods, the transparent conductive film 15 and the protective film 16 may be formed on the back surface side (surface opposite to the touch surface T) of the curved substrate 14.

  Hereinafter, the entire configuration of the display device 10 will be described with reference to FIG. 1 again. The LED 11 and the liquid crystal panel 12 function as an image projection unit that projects an image on the back surface of the curved touch panel 13. More specifically, the LED 11 is a light source that emits light with a predetermined luminance, and is disposed on the opposite side of the curved touch panel 13 with the liquid crystal panel 12 interposed therebetween. The liquid crystal panel 12 is a transmissive liquid crystal panel. The liquid crystal panel 12 displays an image based on a video signal supplied from a drive circuit (not shown).

  Part of the light emitted from the LED 11 passes through the liquid crystal panel 12 and reaches the curved touch panel 13 (see FIG. 1). As described above, since the light scattering layer is provided on the back surface of the curved touch panel 13, the light reaching the curved touch panel 13 is scattered on the back surface of the curved touch panel 13. Thereby, an image displayed on the liquid crystal panel 12 (more precisely, an image displayed in the area A on the liquid crystal panel 12) is projected on the back surface of the curved touch panel 13.

  A user of the display device 10 sees an image projected on the back surface of the curved touch panel 13 (hereinafter referred to as a projected image), not an image displayed on the liquid crystal panel 12. Therefore, the user can correctly touch the point on the curved touch panel 13 corresponding to the point to be touched on the display screen while viewing the projected image from any direction.

  The screen size of the liquid crystal panel 12 included in the display device 10 is determined according to the configuration of the optical system that projects the image, the brightness and resolution of the projected image, and the like. The screen size of the liquid crystal panel 12 is typically 1/10 to 1 times the size of the curved touch panel 13, but may be larger or smaller than that.

  As described above, according to the display device 10 according to the present embodiment, an image is projected on the back surface of the curved touch panel 13, so that a positional shift (parallax) due to a difference in line-of-sight direction is reduced, and the touch position The deviation can be reduced. In particular, in the display device 10, the light transmitted through the liquid crystal panel 12 is directly projected without passing through a lens. However, since the LED 11 plays almost the same function as a point light source, the blur of the projected image is relatively small. Therefore, according to the display device 10, the above-described effect can be obtained by using a small number of optical components.

(Second Embodiment)
FIG. 4 is a diagram showing a configuration of a display device with a touch panel according to the second embodiment of the present invention. A display device 20 shown in FIG. 4 is obtained by adding a condenser lens 21 and a projection lens 22 to the display device (FIG. 1) according to the first embodiment. Among the constituent elements of the present embodiment, the same constituent elements as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The condenser lens 21 collects a part of the light emitted from the LED 11. The light collected by the condenser lens 21 passes through the liquid crystal panel 12 and then reaches the curved touch panel 13 via the projection lens 22 (see FIG. 4). Similar to the first embodiment, since the light scattering layer is provided on the back surface of the curved touch panel 13, the light reaching the curved touch panel 13 is scattered on the back surface of the curved touch panel 13, and on the back surface of the curved touch panel 13. The image displayed on the liquid crystal panel 12 is projected.

  Therefore, according to the display device 20 according to the present embodiment, as in the first embodiment, it is possible to reduce the position shift (parallax) due to the difference in the viewing direction and to reduce the touch position shift. . In particular, since the display device 20 includes the projection lens 22, blurring of the projected image can be reduced even when the projection magnification is large.

  When the curved touch panel 13 has a hemispherical shape (dome shape), as shown in FIG. 5, a fish-eye lens 31 having an intentionally curved image surface may be used as the projection lens. According to the display device 30 including the fisheye lens 31, the length of the optical system from the light source to the projection lens can be shortened, and the display device can be thinned (in FIG. 5, the length in the vertical direction is shortened).

  About the display apparatus with a touch panel of this invention, the modification shown below can be comprised. For example, in the above description, the image projection unit includes the LED 11 as a light source, but may include a halogen lamp, a short arc lamp, or the like instead.

  In the above description, the image projection unit includes the transmissive liquid crystal panel 12 as a non-light-emitting display panel. However, the image projection unit includes a reflective liquid crystal panel as a non-light-emitting display panel. A display panel having a reflective display element such as a DMD (Digital Micromirror Device) may be included. When a non-light emitting display panel is used, it is necessary to provide a light source in the image projection unit, but the display device may or may not be provided with a projection lens.

  Alternatively, the image projection unit includes a self-luminous display panel such as a fluorescent display tube, an inorganic or organic EL display element, or an SED (Surface-conduction Electron-emitter Display) instead of the non-luminous display panel. Also good. When a self-luminous display element is used, it is not necessary to provide a light source in the image projection unit, but it is necessary to provide a projection lens in the display device.

  According to the display device with a touch panel according to these modified examples, as in the first and second embodiments, the positional deviation (parallax) due to the difference in the line-of-sight direction is reduced, and the positional deviation of the touch position is reduced. Can do.

It is a figure which shows the structure of the display apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the basic structure of the curved touch panel contained in the display apparatus shown in FIG. It is a figure which shows the method of providing a light-scattering layer in the back surface of the curved touch panel contained in the display apparatus shown in FIG. It is a figure which shows the structure of the display apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the display apparatus which concerns on the modification of the 2nd Embodiment of this invention. It is a figure which shows the shift | offset | difference of the touch position in a display apparatus with a touch panel.

Explanation of symbols

10, 20, 30 ... display device 11 ... LED
DESCRIPTION OF SYMBOLS 12 ... Liquid crystal panel 13 ... Curved touch panel 14 ... Curved substrate 15 ... Transparent electrically conductive film 16 ... Protective film 17 ... Light-scattering layer 18 ... Screen member 21 ... Condensing lens 22 ... Projection lens 31 ... Fisheye lens

Claims (8)

A display device with a touch panel,
A capacitive touch panel having a curved touch surface and a light scattering layer on the back;
A display device comprising: an image projection unit that projects an image on a back surface of the touch panel.   The display device according to claim 1, wherein the touch panel includes a curved substrate formed of a light-transmitting material and having a back surface coated with a light-scattering paint.   The display device according to claim 1, wherein the touch panel includes a curved substrate that is formed of a light-transmitting material and is roughened on a back surface.   The display device according to claim 1, wherein the touch panel includes a curved substrate formed of a light scattering material. The touch panel includes a curved substrate formed of a light transmissive material,
The display device according to claim 1, further comprising a screen member formed of a material having a light scattering property and disposed along a back surface of the curved substrate. The image projection unit includes a light source and a non-light emitting display panel,
The display device according to claim 1, wherein the light emitted from the light source is directly projected on the back surface of the touch panel after being transmitted or reflected by the display panel. The image projection unit includes a light source, a non-luminous display panel, and a projection lens.
The display device according to claim 1, wherein the light emitted from the light source is transmitted or reflected by the display panel and then projected onto the back surface of the touch panel by the projection lens. The image projection unit includes a self-luminous display panel and a projection lens,
The display device according to claim 1, wherein light emitted from the display panel is projected onto a back surface of the touch panel by the projection lens.

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