WO2013128734A1

WO2013128734A1 - Input device, and input system provided with said input device

Info

Publication number: WO2013128734A1
Application number: PCT/JP2012/080854
Authority: WO
Inventors: 岡田　訓明; 藤原　恒夫
Original assignee: シャープ株式会社
Priority date: 2012-02-29
Filing date: 2012-11-29
Publication date: 2013-09-06
Also published as: JP5886080B2; JP2013182345A

Abstract

A/an (coordinate) input device for implementing input coordinate detection with high reliability while having a simple configuration is provided. The input system (50) in one aspect of the present invention is provided with a pen input device (40) and a light-emitting pen (3), the pen input device (40) being provided with: a light-guide plate (1) in which the light of the pen (3) is propagated through the interior; an optical member (60) for removing light from the light-guide plate (1) to modify the optical path thereof; and imaging units (10, 20) for capturing light in which the optical path has been changed by the optical member (60) in mutually differing locations. The optical member (60) is bonded and secured to the side surface or rear surface of the light-guide plate (1).

Description

Input device and input system including the input device

The present invention relates to an input device that detects coordinates of an input position, and an input system including the input device.

An input system that combines an operation member (hereinafter referred to as a pen) such as a touch pen or a stylus pen and a coordinate input device (also referred to as a position detection device) such as a tablet or a touch panel that accepts coordinate input by the pen is known. Yes. The pen is brought into contact with the coordinate input area of the coordinate input device, and the coordinate input device obtains the coordinates of the position where the pen is in contact (hereinafter referred to as touch). The obtained coordinates are, for example, for displaying an object such as a point image or a straight line image on a display screen such as a liquid crystal display separate from the coordinate input device, or a liquid crystal panel laminated integrally with the coordinate input device. Used for.

FIG. 8 is a schematic configuration diagram showing the coordinate input device described in Patent Document 1. As shown in FIG. 8, the four

corners

200a, 200b, 200c, and 200d of the flat plate member 202 formed in a state where the fluorescent dye 201 is uniformly added are formed in a concave surface, and the

light receivers

203a, 203b, and 203c are directed toward the concave surface. , 203d are arranged. The

light receivers

203a, 203b, 203c, and 203d are connected to the detection circuit unit 211, respectively. As a result, of the light that propagates through the flat plate member 202 and reaches the concave surfaces of the four corners 200a to 200d, only the light directed to the light receivers 203a to 203d is emitted toward the light receivers 203a to 203d. Is refracted toward other than the light receivers 203a to 203d when emitted from the concave surface to the outside.

Light absorbing members

204a, 204b, 204c, and 204d are disposed on the four sides of the flat plate member 202. It is used in combination with a light source unit 205 that is moved manually on the upper surface of the flat plate member 202. Specifically, the spot light emitted from the light source unit 205 is incident on the inside from the upper surface of the flat plate member 202. The fluorescent dye 201 added to the inside of the flat plate member 202 is excited and emits light when incident light hits it. At this time, the light is emitted isotropically. And the position which the fluorescent dye 201 excited and light-emitted is specified using

light receiver

203a, 203b, 203c, 203d.

As shown in FIG. 9A, the touch panel described in Patent Document 2 includes a light guide plate 1101, a light source 1102 that makes light incident on the light guide plate 1101, a light receiving element 1104 that is disposed on a part of the side surface of the

light guide plate

1101, 1105 and an image forming unit 1107 that forms an image on the

light receiving elements

1104 and 1105 with light from the light source 1102 scattered by the detection target 1201 between the side surface of the light guide plate 1101 and the light receiving element. Then, a light absorbing means 1108 is arranged on a part of the side surface of the light guide plate 1101 on which the

light receiving elements

1104 and 1105 are arranged. The light receiving

elements

1104 and 1105 are irradiated with a light source 1102 as shown in FIG. Arranged outside the range. As shown in FIG. 9B, the corners of the light guide plate 1101 on which the

light receiving elements

1104 and 1105 are disposed are planar, that is, a notch 1222 having a surface perpendicular to the surface of the light guide plate 1101. Is provided. The light receiving

elements

1104 and 1105 receive light emitted from the surface of the notch 1222.

Japanese Patent Laid-Open No. 11-327769 (published on November 30, 1999) JP 2009-258967 A (published on November 5, 2009)

However, both Patent Documents 1 and 2 described above need to be provided with notches at the corners of the light guide plate, and the manufacturing process of the light guide plate is complicated. In particular, when the light guide plate is made of glass, notch processing is not easy and the cost is high.

The present invention has been made in view of the above problems, and its purpose is to propagate propagating light propagating radially inside the light guide plate without providing a structure for extracting propagating light in the conductive light plate itself. A highly reliable (coordinate) input device capable of detecting the position coordinates of the light incident position on the upper surface of the light guide plate from the plurality of positions separated from each other in the light guide plate, and the input An object of the present invention is to provide an input system including the apparatus.

Therefore, in order to solve the above problems, an input device according to the present invention includes:
A light guide plate capable of bringing a detection object into contact with the upper surface and propagating light therein;
An optical member having an adjacent surface adjacent to the lower surface of the light guide plate, wherein a part of the propagation light of the light guide plate is taken out and incident through the adjacent surface from a plurality of locations separated from each other in the light guide plate, An optical member that emits the incident light downward from the lower surface of the light guide plate, and
A light receiving means for receiving the light extracted from each of the locations and emitted from the optical member;
Detecting means for detecting a change in propagating light due to contact of the detected object with the upper surface based on a light reception result of a light receiving means, and detecting a position coordinate of a contact position of the detected object with the upper surface; It is characterized by having.

According to the above configuration, the optical member extracts a part of the propagation light from the light guide plate and makes it incident, and the incident light is emitted downward from the lower surface of the light guide plate. There is no need to provide a configuration for emitting propagating light downward from the lower surface of the light guide plate, for example, a notch provided in a conventional configuration. For example, even when the light guide plate is made of glass, according to the configuration of the present invention, the manufacturing cost of the light guide plate can be suppressed as compared with the case where the light guide plate itself is provided with a notch.

Moreover, in addition to said structure, one form of the input device which concerns on this invention is
A part of the end surface of the optical member is a conical surface or a hyperboloid,
The optical path of the light incident on the optical member is preferably changed by the conical surface or the hyperboloid.

According to the above configuration, since a part of the end surface of the optical member is a conical surface or a hyperboloid, it is possible to collect light from a wide range and guide the light to the light receiving means. Therefore, the detectable range of the light incident position of the light guide plate can be realized in a wide range on the upper surface of the light guide plate.

Moreover, in addition to said structure, one form of the input device which concerns on this invention is
The optical member is preferably made of a material having the same or higher refractive index than the light guide plate.

According to the above configuration, since the optical member is made of a material having a refractive index higher than that of the light guide plate, the light extraction efficiency from the light guide plate to the optical member can be improved.

Moreover, in addition to said structure, one form of the input device which concerns on this invention is
The light guide plate is preferably made of glass.

According to the above configuration, since the light guide plate functions as a protective glass, it is excellent in environmental resistance and can contribute to the realization of highly accurate position coordinate detection without causing bending.

Moreover, in order to solve said subject, the input system which concerns on this invention
An input device having the above configuration;
An operation member that comes into contact with the upper surface of the light guide plate and emits light from the contacted position.

According to the above configuration, it is possible to provide an input system that performs a highly reliable input coordinate detection with a simple configuration.

Moreover, in addition to said structure, one form of the input system which concerns on this invention is
An image display panel having a plurality of pixels;
It is preferable to drive the pixels of the image display panel based on the position coordinates detected by the detection means.

According to the above configuration, the pixel corresponding to the position coordinate on the image display panel can be driven and viewed.

According to the present invention, it is possible to realize a (coordinate) input device that realizes highly reliable input coordinate detection with a simple configuration, and an input system including the input device.

It is a perspective view which shows the structure of the input system of one Embodiment of this invention. FIG. 2 is a cross-sectional view taken along line AA ′ shown in FIG. It is a figure which shows the optical member of the input system of one Embodiment of this invention. It is a figure which shows the structure of the pen of the input system of one Embodiment of this invention. It is a figure of the acquired image acquired in the image sensor with which the pen input device of the input system of one embodiment of the present invention was equipped. It is a figure which shows the structure of a part of input system of other embodiment of this invention. FIG. 3 is a cross-sectional view taken along line BB ′ shown in FIG. It is a figure of a conventional structure. It is a figure of a conventional structure.

Embodiment 1
An embodiment of an input system according to the present invention will be described with reference to FIGS. Hereinafter, an embodiment of the input system according to the present invention will be mainly described, and a pen input device which is an embodiment of the input device according to the present invention will be described.

FIG. 1 is a perspective view showing the configuration of the input system of this embodiment.

(1) Configuration of Input System As shown in FIG. 1, the input system 50 of the present embodiment includes a pen input device 40 and a pen 3 (operation member), and is the surface of the pen input device 40. When the pen 3 touches (contacts) the touch surface (upper surface), the touch position coordinates on the touch surface can be obtained.

● Pen input device 40
As shown in FIG. 1, the pen input device 40 includes a liquid crystal display panel 2 (image display panel), a rectangular light guide plate 1 disposed on the display surface side of the liquid crystal display panel 2, and a back surface of the light guide plate 1. And an imaging unit 10 and 20 (light receiving means) disposed at a position where light is emitted from the optical member 60, and a detection device (detection means) (not shown).

The liquid crystal display panel 2 has a liquid crystal layer sandwiched between a pair of substrates, and each substrate is provided with at least various electrodes for changing the orientation of liquid crystal molecules in the liquid crystal layer by applying a voltage. Then, by changing the orientation of the liquid crystal molecules by applying a voltage, the amount of light transmitted through the liquid crystal layer of each pixel is adjusted to perform a desired display. As the configuration of the liquid crystal display panel 2, a conventionally known liquid crystal display panel can be used.

The light guide plate 1 is a rectangular flat plate made of a translucent material, and is disposed on the display surface side of the liquid crystal display panel 2 as shown in FIG. As shown in FIG. 1, the light guide plate 1 is configured such that one side where the

imaging units

10 and 20 are disposed is larger than the liquid crystal display panel 2, and at least a part of each of the

imaging units

10 and 20 is provided on the back surface (lower surface). It is arranged on the side. Thereby, the enlargement of the size of the direction which spreads along the touch surface of the pen input device 40 is suppressed, and it contributes to realization of a compact size.

The surface of the light guide plate 1 opposite to the liquid crystal display panel 2 is a touch surface touched by the pen 3. That is, the light guide plate 1 is on the outermost surface of the pen input device 40.

The light guide plate 1 is made of glass. Thereby, compared with the case where it comprises with a plastic, it is excellent in environmental resistance, and a bending does not arise. The present invention is a mechanism that detects the propagation direction of light propagating through the inside of the light guide plate, and based on that, detects the light incident position on the light guide plate, that is, the position coordinates of the touch position. Therefore, aside from environmental resistance, bending causes the detection accuracy to deteriorate. Therefore, when the light guide plate 1 is made of glass as in the present embodiment, there is no bending and it is possible to contribute to the realization of highly accurate position coordinate detection. However, in the present invention, the material of the light guide plate is not limited to glass, and may be configured using plastic or a conventionally known material as a light guide material other than these.

In the light guide plate 1, part of the propagation light is extracted from the back surface of the light guide plate 1 to the optical member 60 described later, so that it is not necessary to provide a notch in the light guide plate as in the conventional configuration. That is, the light guide plate 1 only needs to have a configuration (structure) capable of propagating light therein, and no other processing is necessary.

The optical member 60 is a translucent material disposed between the back surface of the light guide plate 1 and

imaging units

10 and 20 described later.

2 is a view showing the outer shape of the optical member 60, and FIG. 3 is a cross-sectional view taken along the line AA ′ shown in FIG.

The optical member 60 has a flat upper surface (adjacent surface) and is bonded and fixed to the back surface of the light guide plate 1 as shown in FIG. The optical member 60 has a configuration in which light propagating inside the light guide plate 1 is extracted from the back surface of the light guide plate 1, and the extracted light is incident on itself and coupled inside to propagate inside. ing. The bonding method between the optical member 60 and the light guide plate 1 is not particularly limited. However, as described above, since the optical member 60 takes out light from the light guide plate 1 and makes it incident, a method or material that does not hinder this is used. Use to fix.

The optical member 60 is made of a material having the same or higher refractive index than the light guide plate 1. This prevents light propagating in the light guide plate 1 from being reflected at the boundary surface between the optical member 60 and the light guide plate 1 and returning to the inside of the light guide plate 1 again, thereby improving the light extraction efficiency from the light guide plate 1. Can be increased. In this embodiment, since the light guide plate 1 is made of glass, the optical member 60 is made of high refractive index glass or polycarbonate having a higher refractive index than glass. Thereby, it is possible to efficiently extract light from the light guide plate 1 and to enter the optical member 60.

In addition, as mentioned above, since this invention can comprise a light-guide plate from materials other than glass, for example, when a light-guide plate is an acrylic, an optical member is similarly comprised from an acrylic, high refractive index glass, and a polycarbonate. can do.

In the present embodiment, the optical member 60 is made of a material having a refractive index higher than that of the light guide plate 1, but light propagated inside the light guide plate 1 is at the boundary surface between the optical member 60 and the light guide plate 1. The optical member 60 may be made of a material having the same refractive index as that of the light guide plate 1 as long as it does not reflect and return to the inside of the light guide plate 1 again.

As shown in FIGS. 2 and 3, the optical member 60 is provided with a concave conical cutout 60a in a region near the corner of the light guide plate 1 on the end surface adjacent to the upper surface. The angle (γ shown in FIG. 2) formed by the conical surface of the cutout 60a and the back surface of the optical member 60 is 45 degrees or less, and 30 degrees or 45 degrees is selected. The conical cutout 60a may be provided with a mirror coating (optical path changing portion).

Then, as shown in FIG. 2, the light that propagates through the optical member 60 and reaches the notch 60a changes along the optical path toward the lower side of the optical member 60, that is, toward the back surface of the optical member 60. Let That is, the light propagated through the light guide plate 1 travels downward from the lower surface of the light guide plate 1.

In the present embodiment, the cutout 60a is formed in a conical surface shape, but the present invention is not limited to this, and may be formed in a hyperboloid shape or a polygonal surface shape.

In this embodiment, the shape of the optical member 60 is similar to a fan shape as shown in FIG. 3 when viewed from the upper surface side, but is not limited to this.

The manufacturing method of the optical member 60 is not particularly limited, but can be manufactured at low cost by plastic molding or glass molding.

The optical member 60 is disposed on the back surface in the vicinity of two adjacent corners of the four corners of the rectangular light guide plate 1 as shown in FIG. The arrangement position of the optical member 60 is not limited to this. Since the two

imaging units

10 and 20 are arranged apart from each other in order to realize a detection method to be described later, the light that has propagated through the light guide plate 1 corresponds to the arrangement position of the

imaging units

10 and 20. The optical member 60 may be disposed in the middle of the path of light finally incident on each of the imaging units.

The

imaging units

10 and 20 are arranged immediately below the conical cutout 60 a of the optical member 60, and are arranged at two positions apart from each other at the end of the light guide plate 1. Further, the

imaging units

10 and 20 do not protrude above the touch surface of the light guide plate 1. The imaging unit 10 includes a lens 11, a visible light cut filter 12, and an imaging element 13. Similarly, the imaging unit 20 includes a lens 21, a visible light cut filter 22, and an imaging element 23. The

imaging units

10 and 20 are connected to at least one of the light guide plate 1 and the optical member 60, and have a structure in which light that does not propagate through the light guide plate 1 is not coupled to the

imaging elements

13 and 23.

● Pen 3
On the other hand, the pen 3 corresponding to the pen input device 40 is an operation member called a touch pen or a stylus pen. The details of the pen 3 of the present embodiment will be described with reference to FIG.

FIG. 4 is a cross-sectional view showing the configuration of the pen 3. The pen 3 has a light emitting unit 30 that has a light emitting element 31 that emits infrared light and a light guide member 32 that guides the infrared light to the tip of the pen 3, and a power supply device 33. And the control device 34 are stored. As a characteristic configuration of the pen 3 according to the present embodiment, the light emitting unit 30 is arranged at the tip of the pen 3, and a light diffusion member 36 that diffuses light is attached to the light emitting side. There is a point.

The light diffusing member 36 is made of a resin containing a light diffusing material. Glass beads can be used as the light diffusion material. As the resin, a fluororesin (specifically, polytetrafluoroethylene) and silicon rubber can be used, and it is preferable that the resin is configured to have elasticity. By using an elastic material, when the light guide plate 1 of the pen input device 40 is used by contacting the tip of the pen 3, that is, the light diffusion member 36, the surface of the light guide plate 1 is not damaged and slightly touched by contact. Since the portion is deformed and the contact area with the surface of the light guide plate 1 can be increased, the amount of light coupled to the surface of the light guide plate 1 can be increased.

The light exit surface of the light diffusing member 36 has a curved surface as shown in FIG. That is, the light diffusing member 36 is generally hemispherical. Note that the curved surface does not need to be configured with a uniform curvature, and the curvature may be different between the region that is the tip of the pen 3 and the region that surrounds it. The curved surface may have a fine uneven shape on the surface.

Further, it is preferable that the light emitting surface of the light diffusing member 36 is subjected to wear resistance processing. This is unnecessary when the light diffusing member 36 is made of polytetrafluoroethylene, but when the light diffusing member 36 is made of another material that is not excellent in wear resistance, the light emission It is effective to apply a wear resistant process to the surface. Although there is no restriction | limiting in particular with an abrasion-resistant process, For example, the process which coats the polytetrafluoroethylene on the light-projection surface of the light-diffusion member 36 is mentioned.

Furthermore, the light diffusing member 36 is configured to be detachable from the pen 3. Even if the light diffusing member 36 is damaged for some reason (including deterioration with time), the use of the pen 3 can be continued only by replacing the light diffusing member 36. Compared to the configuration in which the pen 3 is replaced, the use can be continued at a low cost. In order to be detachable, the member on the side to which the light diffusing member 36 is attached (in this embodiment, the light guide member 32) has a groove structure, an occlusal structure, or a portion in contact with the light diffusing member 36, or A fitting structure is provided (not shown), and the light diffusion member 36 is provided with a structure that matches the structure (not shown). In the present embodiment, the light diffusion member 36 is attached to the light guide member 32. However, the present invention is not limited to this, and the light diffusion member 36 may be attached to the housing 35. It may be other embodiments.

The light emitting element 31 may be an LED (light emitting diode) or an LD (laser diode) that emits infrared light. The number of LEDs or LDs is not limited to one provided for one pen 3, and a plurality of LEDs or LDs may be mounted.

Infrared light from the light emitting element 31 that receives light from the power supply device 33 and enters the light diffusing member 36 through the light guiding member 32 enters the light diffusing material 36 and the fine light. Diffusely reflected by unevenness. And it is radiate | emitted as diffused light from the light-projection surface of the light-diffusion member 36. FIG.

The power supply device 33 may be configured to include a battery, for example, or may be configured to be rechargeable.

The control device 34 controls the light emission of the light emitting element 31. For example, a mechanism that emits light only when the light emitting element 31 comes into contact with the light guide plate 1 is included. This mechanism is configured by using a pressure-sensitive switch or the like, and can control the light emission time, thereby reducing power consumption and extending battery life.

As described above, the pen 3 is provided with a light source that emits infrared light, and the infrared light is diffused and emitted from the pen tip. When the pen tip of the pen 3 comes into contact with the light guide plate 1, a part of the infrared light emitted from the pen tip is coupled to the light guide plate 1 and propagates through the light guide plate 1. Since the pen 3 diffuses and emits infrared light from the pen tip, the light coupled to the light guide plate 1 diffuses and radiates inside the light guide plate 1. Thereby, a position coordinate can be calculated | required accurately.

The

imaging units

10 and 20 respectively capture infrared light (hereinafter referred to as

propagation light

4a and 4b) propagating inside the light guide plate 1 through the optical member 60 as shown in FIG. From the images obtained from the image sensor 13, the two-dimensional position coordinates of the contact are obtained. The light receiving surface of the image sensor 13 is disposed so as to be parallel to the surface of the light guide plate 1. Hereinafter, the detection principle of pen input will be described in detail.

(2) Pen input detection principle When the pen tip of the pen 3 comes into contact with the touch surface (transparent light guide plate surface) of the pen input device, part of the infrared light emitted from the light pen is guided by the refractive index N ₁ . The light enters the optical plate 1. Of this incident light, the propagation angle θ _P in the light guide plate 1 is expressed by the formula:
sin (90 ° −θ _P )> 1 / N
The light beam satisfying the conditions shown in FIG. 2 is confined in the light guide plate 1, is repeatedly reflected on the front and back surfaces of the light guide plate 1, and travels in the light guide plate 1. Then, when reaching the interface between the light guide plate 1 and the optical member 60, the light propagating through the light guide plate 1 enters the optical member 60 having a refractive index N ₂ (N ₂ > N ₁ ). As shown, the propagation angle θ _P in the optical member 60 is given by the formula;
sin (90 ° −θ _P )> 1 / N
The light beam satisfying the conditions shown in FIG. 5 is confined in the optical member 60, is repeatedly reflected on the front surface and the back surface of the optical member 60, and travels in the optical member 60.

As a result, the infrared light emitted from the pen 3 is diffused radially around the pen tip and propagates in the light guide plate 1, and some of the

light beams

4 a and 4 b (FIG. 1) When guided to the conical surface notch 60 a of the optical member 60, it is reflected by the conical surface, guided below the optical member 60, and received by the

imaging units

10 and 20. In the

imaging units

10 and 20, the emitted light from the optical member 60 is first collected by the

lenses

11 and 21, then passes through the visible light cut filters 12 and 22, and finally received by the

imaging elements

13 and 23. Is done. The visible light cut filters 12 and 22 transmit infrared light emitted from the pen 3 and serve to block light in other wavelength bands. The visible light cut filter 12 blocks sunlight and stray light such as liquid crystal display panel backlight light, and can increase the SN ratio.

Here, FIG. 5 is a diagram for explaining the detection principle.

As shown in FIG. 5A, the light emitted from the pen 3 propagates through the light guide plate 1 and the optical member 60, and the emitted light forms a linear image 15 on the image sensor 13 through the lens 11. . The position of the linear image 15 changes depending on the position of the pen 3, and by analyzing the acquired image of the imaging unit, angles α and β formed by the

light beams

4a and 4b and one side of the light guide plate 1 are obtained, respectively. Using the principle of surveying, the position coordinates of the point where the pen tip serving as the light source contacts is obtained. In FIG. 5A, when the pen is at the position 3a, a linear image 15 is formed. When the pen moves to the position 3b, a linear image 17 is formed.

FIG. 5B shows an acquired image of the image sensor 13. When the pen tip of the pen 3 in the state of irradiating infrared rays is not in contact with the light guide plate 1, nothing appears in the acquired image of the image sensor 13. On the other hand, when the pen tip of the pen 3 in the state of irradiating infrared rays comes into contact with the light guide plate 1 and infrared light is coupled to the light guide plate 1, as shown in FIG. The light beam 4a is guided to the image sensor 13 via the optical member 60, a linear image is formed on the imaging surface of the image sensor 13, and the linear image 15 appears on the acquired image.

The position of the linear image 15 shown in FIG. 5 changes depending on the position of the contact point of the pen tip of the pen 3, and when the position of the contact point of the pen tip is changed, the linear image is a line indicated by a broken line. It changes like the image 17. The locus of the linear image is a fan shape 16 indicated by a one-dot chain line. The rotation angle α ₁ ′ of the line segment connecting the fan-shaped center 18 and the linear image (with the center of the arc as the rotation center) is the line segment connecting the pen 3 and the image sensor 13 and the side A of the light guide plate 1. Is the same angle as the angle α ₁ formed by. Alpha _{1 'is} found, alpha _1' from the acquired image of the imaging element alpha ₁ is obtained from. Similarly, when the pen is moved to the position of the 3b, formed a line-shaped image 17, by obtaining the inclination alpha _{2 'of} the line-shaped image 17, alpha ₂ is calculated.

Similarly, for the image sensor of the image pickup unit 20, the position of the light emitting point is specified from the analysis of the acquired image, and the angle β formed by the line segment connecting the pen 3 and the image sensor and the side A is obtained.

Then, when the interval between the image sensors is L, the displacement angle of the bright spot obtained by reading the image from the image sensor 13 is α, and the displacement angle of the bright spot obtained by reading the acquired image from the image sensor 23 is β, The coordinates (X, Y) of the bright spot are the following relational expressions (1) and (2);
Y = tan α · X (1)
Y = tan β · (L−X) (2)
Satisfied. Solving this, the coordinates (X, Y) of the bright spot are
X = tan β · L / (tan α + tan β) (3)
Y = (tan α · tan β) · L / (tan α + tan β) (4)
The coordinates X and Y of the point where the pen tip contacts are obtained by α and β obtained as described above and L that can be obtained in advance. Among these, L is an interval between the image sensor 13 and the image sensor 23 and is a fixed value. By obtaining α and β, pen input coordinates X and Y (position coordinates) can be obtained.

Note that the interval L between the image pickup elements is a distance between the optical axis center of the lens 11 and the optical axis center of the lens 21.

In order to obtain the position coordinates of the pen 3 by the above method, the input system 50 is provided with a position coordinate detector (not shown). The position coordinate detection unit can be provided in the pen input device 40.

Further, based on the position coordinates of the pen 3 obtained by the above method, the pixel at the position corresponding to the position coordinates of the liquid crystal display panel 2 is driven, and the user visually recognizes the touch position of the pen 3. Is possible. For this purpose, if a control unit (not shown) that controls the driving of the liquid crystal display panel 2 acquires information on the position coordinates obtained by the position coordinate detection unit and drives the liquid crystal display panel 2 based on the information. Good.

As described above, the input system 50 according to the present embodiment can obtain the position coordinates of the pen 3 by capturing the propagated light at at least two locations apart from each other in the light guide plate 1.

Further, according to the configuration of the pen input device 40 of the present embodiment, since the imaging unit is provided at a position that does not protrude upward from the touch surface of the light guide plate 1, the touch surface of the light guide plate 1 is the pen input device 40. The imaging unit does not protrude above the touch surface. Therefore, even when the pen input device 40 of the input system 50 of this embodiment is applied to a table type terminal, the table surface can be made completely flat without the surroundings rising like a bank.

In addition, the input system 50 according to the present embodiment is not a light shielding method, but has a configuration in which light that has propagated inside the light guide plate is received by the imaging device, so that there is no possibility of erroneous recognition due to stray light including sunlight. Accurate position detection can be realized, and therefore it is possible to place the device outdoors or near a window.

In the pen input device 40 of the input system 50 according to the present embodiment, the

imaging units

10 and 20 that receive the light emitted from the tip of the pen 3 are connected to the light guide plate 1 and light that does not propagate through the light guide plate 1 is imaged. The structure is not coupled to the element. Therefore, even if illumination light is applied from the normal direction of the touch surface of the light guide plate 1, the light is not coupled to the light guide plate 1, so stray light is not guided to the imaging element. For this reason, the pen input device 40 is not easily affected by external light, and can be disposed outdoors or near a window.

In the present embodiment, the light emitted from the tip of the pen 3 is configured to diffuse by the light diffusion member 36 provided at the tip of the pen 3. Thereby, a sufficient amount of light can be coupled to the light guide plate 1 without depending on the inclination angle of the pen 3. Therefore, accurate position detection can be realized.

In addition, although this embodiment demonstrated the structure using the image pick-up element 13 and the image pick-up element 23 in total, this invention is not limited to this, Each location in the edge part of the light-guide plate 1 is not limited to this. May be collected in one image sensor using a mirror and a shutter.

In this embodiment, the configuration using one pen 3 has been described. However, the present invention is not limited to this, and even when a plurality of pens are used, for example, the light emission timing of each pen. If a plurality of pens are in contact with the touch surface of the light guide plate 1 at the same time, the respective position coordinates can be obtained.

(3) Effects of this Embodiment According to the configuration of this embodiment, the optical member 60 takes out part of the propagation light from the light guide plate 1 and makes it incident, and the incident light is the lower surface of the light guide plate 1. The light guide plate 1 itself is provided with a configuration for emitting the propagating light downward from the lower surface of the light guide plate 1, for example, a notch provided in the conventional configuration. There is no need. Therefore, the material of the light guide plate 1 is not limited, and the manufacturing cost of the light guide plate 1 can be suppressed as compared with the case where the light guide plate itself is provided with a notch.

[Embodiment 2]
Another embodiment of the input system of the present invention will be described with reference to FIGS. FIG. 6 is a perspective plan view showing the light guide plate 1 and the optical member 60 provided in the pen input device provided in the input system of the present embodiment. FIG. 7 is a cross-sectional view taken along line BB ′ shown in FIG.

The difference between the present embodiment and the first embodiment described above lies in the structure of the optical member and the arrangement position of the imaging unit.

In this embodiment, as shown in FIG. 6, the notch 60a ′ provided in the optical member 60 ′ is not a conical surface but a hyperboloid. The center position of this hyperboloid coincides with the corner position of the light guide plate 1 along the superimposing direction.

As shown in FIG. 7, the optical member 60 ′ takes out light propagating inside the light guide plate 1 from the back surface of the light guide plate 1, makes the extracted light incident on itself, and couples it inside. And is guided to the notch 60a '.

As mentioned above, although embodiment which concerns on this invention was described, this invention is not limited to said embodiment. Various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention.

The present invention can be provided for any type of input system that uses a light emitting pen to determine the coordinate position of the pen.

1 Light guide plate 2 Liquid crystal display panel (image display panel)
3

Pen

4a, 4b Light flux 10 Imaging unit (light receiving means)
DESCRIPTION OF SYMBOLS 11 Lens 12 Visible light cut filter 13 Image pick-up element 16 Fan shape 17 Linear image 18 Center 20 Imaging unit (light-receiving means)
21 Lens 22 Visible Light Cut Filter 23 Image Sensor 30 Light Emitting Unit 31 Light Emitting Element 32 Light Guide Member 33 Power Supply Device 34 Control Device 35 Housing 36 Light Diffusing Member 40 Pen Input Device (Input Device)
50 Input system 60, 60 '

Optical member

60a, 60a' Notch

Claims

A light guide plate capable of bringing a detection object into contact with the upper surface and propagating light therein;
An optical member having an adjacent surface adjacent to the lower surface of the light guide plate, wherein a part of the propagation light of the light guide plate is taken out and incident through the adjacent surface from a plurality of locations separated from each other in the light guide plate, An optical member that emits the incident light downward from the lower surface of the light guide plate, and
A light receiving means for receiving the light extracted from each of the locations and emitted from the optical member;
Detecting means for detecting a change in propagating light due to contact of the detected object with the upper surface based on a light reception result of a light receiving means, and detecting a position coordinate of a contact position of the detected object with the upper surface; An input device characterized by that.
A part of the end surface of the optical member is a conical surface or a hyperboloid,
The input device according to claim 1, wherein an optical path of light incident on the optical member is changed by the conical surface or the hyperboloid.
3. The input device according to claim 1, wherein the optical member is made of a material having the same or higher refractive index than the light guide plate.
The input device according to any one of claims 1 to 3, wherein the light guide plate is made of glass.
An input device according to any one of claims 1 to 4,
An input system comprising: an operation member that contacts the upper surface of the light guide plate and emits light from the contacted position.
An image display panel having a plurality of pixels;
The input system according to claim 5, wherein the pixel of the image display panel is driven based on the position coordinates detected by the detection unit.