JPH11119898A - Touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the positional accuracy and also to reduce the size and thickness of a touch panel by reflecting the light at an operating position of an operating member for display of images, irradiating a photoelectric transducer of an optical area sensor with the light and detecting the irradiated photoelectric transducer to detect the position of this transducer as the position of the operation member. SOLUTION: Plural elements consisting of pixel electrodes used for display of a liquid crystal panel, the photoelectric transducers composing an area sensor 21, etc., are laminated on the same substrate. When an optional position of this touch panel is touched by an input pen 11 on the surface of an protective glass 22, i.e., an operating screen, the light 25 is reflected toward an area sensor 21 at the touched position via the tip part of the pen 11 as the incident light 25a of the sensor 21. The light receiving surface of the sensor 21 is irradiated by the light 25a. Thereby, the sensor 21 detects the position of each photoelectric transducer by detecting the incident light 25a and can display the detected position based on the operation locus of the surface of the glass 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a touch panel for detecting a display position by touching an arbitrary position on an image display device.

[0002]

2. Description of the Related Art Conventionally, the position of a display screen of a liquid crystal display device is specified by touching the display screen with an input pen or the like.
Touch panels that allow information input of items and the like at that position have come to be widely used.

A conventional touch panel is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-95701. In the touch panel described in this publication, a tablet that arranges electrode lines along the X axis and the Y axis and performs position detection by pseudo-grounding when a finger or the like touches the image display device is a separate mechanism. The method is common.

In the above arrangement, when an arbitrary display position is touched according to the content displayed on the image display device, the display content corresponding to the touched position is confirmed.
The contents can be input.

[0005]

However, in the above-mentioned conventional touch panel, since the image display device and the pointing position detecting device are separate mechanisms, it is very difficult to improve the positional accuracy. Was.

[0006] Further, since the position where the pointing is performed is quasi-grounded, two or more pointing positions on the same axis cannot be detected. That is,
There is only one point, and a pointing state in the vicinity cannot be detected. For this reason, there is a case where the state cannot be associated with the display and input becomes impossible.

According to the present invention, in order to solve the above-mentioned conventional problems, an image display device and a pointing position detecting device are provided on the same substrate to improve the positional accuracy and to detect a plurality of pointing positions. It is an object of the present invention to provide a touch panel that enables the touch panel.

Another object of the present invention is to make the touch panel as small as possible, especially thin and light.

[0009]

A touch panel according to the present invention for achieving the above-mentioned object is provided on a display panel for displaying an image, and is operated on a displayed image surface with an operating member such as an input pen. By doing so, in the touch panel for detecting the operation position, provided with an area sensor consisting of a number of photoelectric conversion elements that are arranged without being affected by the display of the display panel and react to light to perform position detection, Reflects light for image display at the position operated by the operation member, irradiates the photoelectric conversion element of the optical area sensor, and detects the photoelectric conversion element irradiated with the light to detect the photoelectric conversion element. The position is detected as the position of the operation member.

According to such a configuration, the operation position of the operation member can be reliably detected by the photoelectric conversion element of the area sensor by using the light of the display device as it is. In this case, since it is not necessary to provide a signal line or the like in the operation member, the operability is improved.

In the touch panel having the above-mentioned configuration, the display panel is formed of a liquid crystal display panel, and light from a backlight provided for display on the liquid crystal display panel is reflected by the operation member. By irradiating this to the photoelectric conversion element of the area sensor, the backlight can be used effectively, and even if the means for detecting the operation position is provided, the apparatus does not become large and the thickness is reduced. The thickness can be reduced without increasing the thickness.

Further, in the touch panel constructed as described above, the photoelectric conversion elements of the area sensor are arranged on the same substrate in correspondence with the display pixel electrodes constituting the display panel, so that the display pixels and the position detection can be performed. Element is 1
Providing a one-to-one correspondence eliminates the problem of positional accuracy and enables a reduction in thickness.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a touch panel of the present invention. In FIG. 1, a touch panel 10 outputs an image, that is, displays an image, and detects an arbitrary operation position on the display surface. This shows a state where the image is displayed on the display device on the image display surface of the touch panel 10 in accordance with the position touched by the input pen 11.
By touching the 0 operation surface, an arbitrary trajectory 12 touched is displayed.

FIG. 2 is a diagram showing the structure of the touch panel 10. In FIG. 2, the touch panel includes a liquid crystal display device (liquid crystal panel) 20 for image display, an area sensor 21 provided corresponding to the liquid crystal panel 20, and protection for protecting the operation surfaces of the liquid crystal panel 20 and the area sensor 21. Glass 22, a reflection sheet 23 provided on the lower surface of the liquid crystal panel 20 and reflecting light on the surface of the liquid crystal panel 20 in order to irradiate light so that an image display by the liquid crystal panel 20 can be viewed artificially. And a backlight 24 which is a light source for irradiating light.

The liquid crystal panel 20 and the area sensor 21
Shows a state in which components that are separately configured are stacked, but a pixel electrode for display of a liquid crystal panel and a photoelectric conversion element such as a photo diode that constitutes the area sensor 21 on the same substrate. Are provided in a stacked manner. The details will be described below.

When the backlight 24 is turned on, the light is reflected by the reflection sheet 23. The reflected light 25 reflected by the reflection sheet 23 is emitted from the entire display area of the liquid crystal panel 20 when the liquid crystal panel 20 does not block light. At this time, the entire display area emits light in a substantially uniform state, and a "white" state is displayed.

Therefore, if an arbitrary position is touch-operated with the input pen 11 on the surface of the protective glass 22 which is the operation surface, the light 25 is emitted from the tip of the input pen 11 at the touch position. The light is reflected to the side 21 and becomes the incident light 25a of the area sensor 21. This incident light 2
5a is irradiated on the light receiving surface side of the area sensor 21. Therefore, in the area sensor 21, the incident light 25a
Is detected, the position is detected, and as shown in FIG. 1, it can be displayed according to the trajectory 12 of the operation on the surface of the protective glass 22.

The display at this time is performed by driving the display of the liquid crystal panel 20 as is well known in the related art, and by shielding the light reflected from the reflection sheet 23, the position is displayed as "black".

The above-mentioned protective glass 22 is not limited to glass, but may be any other glass having light transmittance. The tip of the input pen 11 should preferably have a high light reflectance. Therefore, it is preferable to apply a coating process to a member having a high reflectance at the tip.

FIG. 3 shows a state in which the input pen 11 is slightly away from the touch panel 10. In FIG. 3, the reflected light 25 from the reflection sheet 23 is reflected by the tip end region of the input pen 11 and becomes incident light 25a to the area sensor 21, but the incident light 25a is diffused and diffused into the area sensor 21. Irradiation is performed on the area 21 in a predetermined range 25b. This irradiation state is shown in FIG. FIG. 4A shows an irradiation state on the area sensor 21 in a state where the input pen 11 in FIG. 2 is in contact with the protective glass 22 of the touch panel 10.

Therefore, in FIG. 4B, square areas 1aa regularly and vertically arranged are arranged.
Is a photodiode constituting the area sensor 21, and a circular portion indicates light 25 b reflected and diffused by the input pen 11, that is, an irradiation area. Here, the hatched portion of the photodiode 1aa is a portion that has received the incident light 25b.

FIG. 4A shows a state in which the input pen 11 is in contact with the touch panel 10.
The photodiodes 1aa that are detecting light are indicated by oblique lines, and seven photodiodes 1aa are detecting light. Therefore, in FIG. 4B, 28 photodiodes 1aa are detecting light. Therefore, the photodiodes 1 that are vertically and horizontally adjacent
When the number of aa is two or more and less than nine, the input pen 1
Assuming that 1 is in contact with the touch panel 10, FIG.
In the state of (a), the input pen 11 is
You will be in contact with Further, in the detection state of FIG. 4B, a state where the input pen 11 is separated from the touch panel 10 can be detected.

Accordingly, the reflected light (2) from the input pen 11
5a), if the input pen 11 is in contact with the touch panel 10, a plurality of input positions can be detected.
Therefore, the problem of position accuracy can be solved by detecting a plurality of input positions.

FIG. 5 shows a configuration in which the area sensor 21 and the liquid crystal panel 20 are stacked on the same substrate. In FIG. 5, 1aa is a photodiode of amorphous silicon constituting the area sensor 21 as described above, and 1ba is a pixel electrode for display constituting the liquid crystal panel 20. 1bb arranged in the vertical and horizontal directions are lead wires for connecting the pixel electrodes 1ba in a matrix state.

In the liquid crystal panel 20, as is well known, a signal input line (lead line) 1bb in a horizontal direction (X-axis direction) corresponding to the pixel electrode 1ba as shown in FIG. Are electrically connected to the respective pixel electrodes 1ba in the horizontal direction, and on the other substrate side facing the pixel electrodes 1ba, a pixel electrode corresponding to the pixel electrode 1da and a vertical direction (Y-axis). For example, a lead wire 1bb for inputting a scanning signal is formed, and each pixel electrode is connected in the vertical direction. The two substrates are opposed to each other via a spacer so as to be spaced apart from each other by a certain distance, and a liquid crystal is filled between them, and the periphery is sealed to form a liquid crystal display panel 10.

The area sensor 21 is provided on one of the substrates constituting the liquid crystal panel 20 so as to be laminated on the pixel electrode 1ba and the one lead 1bb in a state where the photodiode 1aa and the photodiode 1aa are insulated from each other. Lead wires 1b for matrix connection of 1aa
b, the lead wires (1, 2, 3,.
., A, B, C,...) Are provided.
In particular, the light receiving surface of the photodiode 1aa is
3 is provided so as to be opposite to the surface facing.
In particular, in the photodiode 1aa, the liquid crystal panel 2
0 may be provided on the side facing the protective glass 22. Therefore, the liquid crystal panel 20 may be provided on the side opposite to the substrate on which the liquid crystal and the pixel electrodes are formed.

FIG. 6 shows a state in which light from the backlight 24 is reflected by a touch operation of the input pen 11 according to the present invention.
The circuit configuration for detecting by the photodiode 1aa at the corresponding position of the area sensor 21 as described above is shown. In FIG. 6, each photodiode 1aa is
They are connected in a matrix, 15 is an amplifier for amplifying a minute current obtained from the photodiode 1aa, and 16 is a photodiode 1a in each row direction (lateral direction).
a changeover switch for selecting a group a; 17 is a photodiode 1aa in the row direction selected by the switch 16
A terminal for applying a bias voltage in the column direction (longitudinal direction) for selecting one photodiode 1aa from the group, and the bias voltage is selectively supplied to lead wires indicated by 1, 2, 3,.... Reference numeral 18 denotes a photodiode 1a
This is an output terminal obtained by amplifying the minute current of a by the amplifier 15 and extracting it.

Each of the photodiodes 1aa has lead wires 1, 2, 3,..., A, B, C,
Are connected to each of the intersections (the lead wires are not electrically connected at this position). The terminals of the lead wires A, B, C,... In the row direction are selectively connected to the ground (GND) or the amplifier 15 via the switch 16 described above. Also, bias voltages are sequentially supplied to the lead wires 1, 2, 3,... In the column direction in a time-division manner.

The amplifier 15 amplifies a small current of the photodiode 1aa sent from one of the lead wires A, B, C,... In the row direction selected by the switch 16,
Output to the output terminal 18. When one row-direction lead wire is selected by the switch 16, the bias voltage is sequentially applied to the column-direction lead wires 1, 2, 3,... In order to select each row-direction position one by one. Is supplied. Therefore, if one of the photodiodes 1aa to which the bias voltage is supplied is irradiated with light, at that time, a detection signal is output from the output terminal 18 via the amplifier 15 to a high level signal, and there is no light irradiation. In this case, an L level signal is output.

For example, when a lead B in the row direction is selected, the other leads A, C,... In the other row are connected to GND by the switch 16, and only the lead B is amplified by the switch 16. 15 is connected. And
A bias voltage is supplied to the lead wire 1 in the column direction (the other lead wires B, C,.
Select At this time, since no light is incident on the photodiode 1aa connected to the intersection of the lead wire 1 and the lead wire B, no current flows through the lead wire B. Therefore, no detection signal is output to the output terminal 18. That is, an L-level signal is output to the output terminal 18.

Next, when a lead wire 2 in the column direction is selected and a bias voltage is supplied to the lead wire 2, light is incident on the photodiode 1aa connected to the intersection with the lead wire B. The photodiode 1aa is ON
Then, the current flows. This current is amplified via the amplifier 15 and an H level signal is output from the output terminal 18 as a detection signal. In this manner, the light on the screen is reflected by the operation of the input pen 11, and the reflected light is incident as described above, whereby the position can be detected.

Here, as shown in FIG.
0 indicates lead wires 1bb, 1b arranged in a matrix.
The display pixel electrode 1ba is provided in a region surrounded by b. By arranging these in a plurality of rows and a plurality of columns, an arbitrary image can be displayed. The drive for this display is well known, and as shown in FIG.
By touching “0”, the position can be detected by the detection circuit shown in FIG. 6, and based on this detection, the operated locus 12 can be displayed on the liquid crystal panel 20.

Further, when an input screen for a large number of input items is displayed on the liquid crystal panel, touching the input item screen with the input pen 11 enables information input of the input items. Also in this case, the area of the touch position of the input pen 11 is made incident on the plurality of photodiodes 1aa as shown in FIG. 4 to detect the position, and the item displayed at that position can be input.

At this time, "white" is displayed in the item input display.
It is displayed in a state of “black” mixed, and when the “black” portion is touched, no light is incident on the photodiode 1aa. Therefore, the image display is stopped instantaneously, and the detection can be easily performed by performing the time division processing of the display phase and the position detection phase. In this case, the switching cycle of the time division processing may be considered so that the display does not flicker.

Although the photodiode 1aa made of amorphous silicon has been described for position detection,
The invention is not limited to this, and any device that detects light may be used. That is, any element that can convert light into an electric signal may be used. For example, a solar cell or the like can be used.

Here, the explanation has been made using the liquid crystal panel 20 as a display device. However, a touch panel for detecting an arbitrary position using a display device such as a CRT can be configured.
That is, as described above, an area sensor in which the photoelectric conversion elements are arranged in a matrix, for example, is provided on the display surface of the CRT, and a transparent protective member having an appropriate thickness is stacked from the upper surface of the area sensor. For this reason, light for display on the CRT is reflected by the input pen 11 and becomes incident light, which is applied to an area sensor provided with photoelectric conversion elements in a matrix to detect its position.

[0037]

According to the touch panel of the present invention, the touch position can be easily detected by using the light of the backlight for the liquid crystal display, so that the device can be reduced in size and thickness.

In addition, since the photoelectric conversion element for position detection is provided in the liquid crystal display device, it is possible to reduce the thickness, and it is possible to make the position of the display pixel correspond to the detection position on a one-to-one basis. Go up.

[Brief description of the drawings]

FIG. 1 is a plan view showing a touch panel according to an embodiment of the present invention, showing a display state following a locus of a touch operation.

FIG. 2 shows the structure of the touch panel of the present invention,
FIG. 7 is a diagram for explaining a state of a touch operation.

FIG. 3 shows the structure of the touch panel of the present invention,
It is a figure showing the state where a touch operation is not performed.

FIG. 4 illustrates a state in which light is irradiated on an area sensor for position detection by the touch panel of the present invention.
(A) shows the state when the touch panel is touched, (b)
FIG. 3 is a diagram showing a state where a touch panel is not touched.

FIG. 5 is a diagram showing an arrangement state of an area sensor and a photoelectric conversion element and a display electrode of a liquid crystal panel which constitute the touch panel of the present invention.

FIG. 6 is a circuit diagram for performing position detection by the area sensor of the present invention.

[Explanation of symbols]

 1, 2, 3, lead wire (for position detection) 10 touch panel 11 input pen 15 amplifier (amplifier) 16 changeover switch 18 output terminal 20 liquid crystal panel (liquid crystal display device) 21 area sensor 22 protective glass 23 reflection sheet 24 back Write A, B, C ... Lead wire (for position detection) 1aa Photodiode (photoelectric conversion element) 1ba Display pixel electrode 1bb Lead wire (for liquid crystal display)

Claims (3)

[Claims] 1. A touch panel provided on a display panel for displaying an image, wherein the touch panel detects an operation position by operating an operation member such as an input pen on a displayed image surface. Provide an area sensor consisting of a number of photoelectric conversion elements that are arranged without being affected by the display and that respond to light to perform position detection, and reflect light for image display at the position operated by the operation member Then, the position of the photoelectric conversion element is detected as the position of the operation member by irradiating the photoelectric conversion element of the optical area sensor and detecting the irradiated photoelectric conversion element. Touch panel. 2. The display panel according to claim 1, wherein the display panel is a liquid crystal display panel, and light from a backlight provided for display on the liquid crystal display panel is reflected by the operation member, and is reflected to a photoelectric conversion element of an area sensor. The touch panel according to claim 1, wherein the touch panel is irradiated. 3. The touch panel according to claim 2, wherein photoelectric conversion elements of the area sensor are arranged on the same substrate so as to correspond to the display pixel electrodes constituting the display panel.