JP2013182343A - Coordinate input device and coordinate input system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coordinate input device and a coordinate input system for detecting the coordinate position of a finger even when applying an optical coordinate input device using a light guide member to a large-sized touch panel.SOLUTION: A coordinate input device 3A includes: a light guide plate 10; light source units 4 for making illumination light incident from the edge part of the light guide plate 10; at lease two imaging units 20, 30 for receiving the illumination light propagating in the light guide plate 10; and a detection part 5 for finding the coordinates of the contact position of a finger 6 with the surface of the light guide plate 10 on the basis of the outputs of the imaging units 20 and 30 which have detected light scattering with the finger 6 when the finger 6 comes into contact with the surface of the light guide 10. The imaging units 20 and 30 are disposed within the irradiation range of the illumination light. The detection part 5 detects the decrease in output strength of the imaging units 20 and 30 based on the light scattering with the finger 6, and finds the coordinates of the contact position of the finger 6 with the surface of the light guide plate 10.

Description

  The present invention includes a plate-shaped light guide member, a light source that makes illumination light incident from an end of the light guide member, at least two light receiving means that receive illumination light propagating in the light guide member, and the light guide member. Detecting means for obtaining coordinates of a contact position of the light guide member on the surface of the detected body based on an output of the light receiving means that detects light scattering by the detected body when the surface of the detected object is contacted The present invention relates to an optical coordinate input device and a coordinate input system.

  An optical coordinate input device or position detection device comprising a bar-shaped operation member (hereinafter referred to as “pen”) such as a touch pen or a stylus pen, or a light guide member that receives coordinate input by a finger or the like, and a coordinate input device or A coordinate input system such as a tablet or a touch panel in which a position detection device and a display panel are combined is known.

  In the coordinate input system, the coordinate input device or the position detection device obtains the coordinates of the approached or touched position of the pen or finger by causing the pen or finger to approach or contact the coordinate input area of the coordinate input device. The obtained coordinates are 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 integrally laminated on the coordinate input device. Used for etc.

  For example, as shown in FIGS. 7A and 7B, the touch panel 100 disclosed in Patent Document 1 includes a light guide plate 101, a light source 102 that makes light incident on the light guide plate 101, and a side surface of the light guide plate 101. The light from the light source 102 scattered by the detected object 110 is imaged on the light receiving elements 104 and 105 between the light receiving elements 104 and 105 arranged in part and the side surface of the light guide plate 101 and the light receiving elements 104 and 105. And an imaging means 107. Further, a light absorbing means 108 is disposed on the side surface of the light guide plate 101 on which the light receiving elements 104 and 105 are disposed. The light receiving elements 104 and 105 are located outside the irradiation range of the light source 102 as shown in FIG. Has been placed.

  The principle of coordinate detection of the touch panel 100 is as follows.

  Light emitted from the light source 102 disposed on the side surface of the light guide plate 101 propagates while repeating total reflection inside the light guide plate 101. In a normal state, since the light receiving elements 104 and 105 are arranged outside the irradiation range of the light source 102, they do not receive propagating light propagating through the light guide plate 101. Here, when the detection object 110 such as a finger is touched on the transparent light guide plate 101, the propagation light is disturbed and scattered light is generated. Part of the scattered light also propagates in the direction of the light receiving elements 104 and 105 and is received by the light receiving elements 104 and 105 as shown in FIGS. Thereby, the azimuth angle is measured, and the point where the scattered light is generated by the triangulation method, that is, the point where the detected object 110 such as a finger is touched is specified.

JP 2009-258967 A (published on November 5, 2009)

  However, in the touch panel 100 disclosed in the above-mentioned conventional patent document 1, as a principle of coordinate detection, the scattered light caused by the presence of the detection object 110 is maintained in a state where the light receiving amount of the light receiving elements 104 and 105 is maintained at zero. The light receiving peak is detected. As a result, if the light receiving elements 104 and 105 are not arranged outside the irradiation range of the light source 102, the amount of light received by the light receiving elements 104 and 105 cannot be maintained at 0, and the light receiving peak of the reflected light from the detection target 110 is obtained. Cannot be detected. For this reason, the arrangement positions of the light source 102 and the light receiving elements 104 and 105 are limited.

  Therefore, for example, since the light source 102 and the light receiving elements 104 and 105 cannot be arranged to face each other, when applied to a large touch panel, a contact detection signal in the detected object 110 far from the light receiving elements 104 and 105 is detected. There is a problem that the quality deteriorates.

  The present invention has been made in view of the above-described conventional problems, and its purpose is to detect a finger or the like even when applied to a large touch panel in an optical coordinate input device using a light guide member. To provide a coordinate input device and a coordinate input system capable of detecting a coordinate position of a body.

  In order to solve the above problems, the coordinate input device of the present invention receives a plate-shaped light guide member, a light source that makes illumination light incident from an end of the light guide member, and illumination light that propagates in the light guide member. Based on the output of the light receiving member in the detected body based on the output of the light receiving means that detects light scattering by the detected body when the detected body contacts the surface of the light guiding member A coordinate input device including a detecting unit for obtaining coordinates of a contact position on the surface, wherein the light receiving unit is provided within an illumination range of the illumination light, and the detecting unit is a light beam by a detected object. A decrease in the output intensity of the light receiving means based on the scattering is detected, and the coordinates of the contact position of the detected body with the surface of the light guide member are obtained.

  According to the above invention, the coordinate input device includes a plate-shaped light guide member, a light source that makes illumination light incident from an end of the light guide member, and at least two light sources that receive illumination light propagating in the light guide member. Based on the output of the light receiving means and the light receiving means that detects the light scattering by the detected object when the detected object is brought into contact with the surface of the light guide member, the surface of the light guide member in contact with the detected object is contacted Detecting means for obtaining the coordinates of the position.

  Here, in the touch panel of Patent Document 1, the light reception peak of scattered light due to the presence of the detection target is detected in a state where the light reception amount of the light receiving means is maintained at zero. As a result, if the light receiving means is not arranged outside the irradiation range of the light source, the amount of light received by the light receiving means cannot be maintained at 0, and the amount of scattered light received by the detected object is very small. In the contact detection of the object to be detected at a distance from the means, the signal quality is lowered, and it is difficult to apply to a large touch panel.

  Therefore, in the present invention, the light receiving means is provided within the illumination light irradiation range, and the detection means detects a decrease in the output intensity of the light receiving means based on light scattering by the detected object, and detects the detected light. The coordinates of the contact position on the surface of the light guide member in the body are obtained.

  That is, in the present invention, the concept is changed with respect to Patent Document 1, and in Patent Document 1, the light receiving peak of scattered light due to the presence of the detected object is detected, whereas in the present invention, the light receiving means is fixed. In a state where a large amount of received light is given, a decrease in output intensity in the light receiving means is detected based on light scattering due to the presence of the detected object.

  As a result, since the light receiving means is provided within the illumination light irradiation range, the light receiving means is constantly given a constant amount of light received, and in this state, the light due to the contact of the detected object far away from the light receiving means. Due to the scattering, a decrease in intensity occurs in the certain amount of received light. For this reason, by detecting this decrease in strength, the coordinates of the contact position of the detected body on the surface of the light guide member can be obtained by the detecting means.

  Therefore, an optical coordinate input device using a light guide member can provide a coordinate input device that can detect the coordinate position of a detection object such as a finger even when applied to a large touch panel.

  In the coordinate input device of the present invention, at least three light receiving means may be provided.

  That is, for example, assume that there are two objects to be detected. In this case, when there are only two light receiving means, if the optical paths of the two detection objects overlap, it cannot be specified which of the two detection objects is present in front. .

  However, if there are three light receiving means, the contact position of each detected object can be obtained for each detected object using the light receiving means using two optical paths that do not overlap.

  Further, when there are two light receiving means, there is a possibility that if the detected object comes into contact with the vicinity of the side of the light guide member provided with the two light receiving means, it becomes a blind spot and cannot be detected by the two light receiving means. . In this case, if there are three light receiving means, for example, if they are arranged at the apex of a triangle, the detected object is brought into contact with any part of the light guide member without generating a blind spot. In addition, it is possible to reliably specify the position coordinates of the contact point of the detected object.

  In the coordinate input device according to the aspect of the invention, it is possible that the light source is configured to allow illumination light to enter from an end portion around the entire periphery of the light guide member.

  As a result, when the light receiving means is arranged along one side of the light guide member, the signal quality deteriorates when the contact point of the detected object is far from the light receiving means, but the signal is increased by increasing the number of light receiving means around the Quality deterioration can be prevented. In this case, it is preferable that a light source exists at a position facing the light receiving means.

  For this reason, the light source is disposed at the end portion of the entire periphery of the light guide member, and the light source is configured to allow illumination light to enter from the end portion of the entire periphery of the light guide member. Means that the entire range of the light guide member is provided within the illumination light irradiation range.

  Therefore, it is possible to reliably specify the position coordinates of the contact point of the detected object regardless of where the detected object is brought into contact with the light guide member.

  In the coordinate input device according to the aspect of the invention, the light receiving unit includes a one-dimensional or two-dimensional image sensor, and illumination light propagating in the light guide member is supplied to the light guide member. It can be assumed that an optical path changing unit that emits in a dotted or linear manner is provided.

  As a result, the illumination light propagating in the light guide member and the attenuated light are respectively emitted to the outside of the light guide member via the optical path conversion unit, and emitted to the respective image pickup devices in a dot shape or a line shape, respectively.

  For this reason, in each light receiving means, the interval between each light receiving means and two angles in a triangle connecting each light receiving means and the contact position of the detected object to the light guide member can be known. The coordinates of the contact position of the detected object to the light guide member can be obtained.

  Accordingly, a coordinate input device using a light guide member and obtaining the coordinates of the contact position of the detected object to the light guide member by triangulation by light scattering due to the contact of the detected object with the light guide member is provided. can do.

  In order to solve the above problems, a coordinate input system according to the present invention is a coordinate input system including the coordinate input device described above, and includes an image display panel.

  According to said invention, a coordinate input device can be functioned as a touchscreen which inputs with to-be-detected bodies, such as a finger, seeing the image of an image display panel. Therefore, an optical coordinate input device using a light guide member is provided with a coordinate input system provided with a coordinate input device that can detect the coordinate position of a detected object such as a finger even when applied to a large touch panel. be able to.

  In the coordinate input device of the present invention, as described above, the image sensor is provided in the illumination light irradiation range, and the detection means reduces the output intensity of the image sensor based on light scattering by the detection target. It detects and obtains the coordinates of the contact position of the detected object to the surface of the light guide member.

  As described above, the coordinate input system of the present invention is a coordinate input system including the coordinate input device described above, and includes an image display panel.

  Therefore, an optical coordinate input device using a light guide member is provided with a coordinate input device and a coordinate input system that can detect the coordinate position of a detected object such as a finger even when applied to a large touch panel. There is an effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view illustrating an overall configuration of a coordinate input system including a coordinate input device according to an embodiment of a coordinate input device and a coordinate input system according to the present invention. 1 shows the overall configuration of the coordinate input system, and is a cross-sectional view taken along line AA in FIG. (A) is a top view which shows the output image of an image pick-up element when a finger is not contacting the light guide plate, (b) is a top view which shows the output image of an image pick-up element when a finger is contacted to the light guide plate It is. (A) is a perspective view which shows the imaging condition in the imaging unit in the said coordinate input device, (b) is a top view which shows the image in the image pick-up element of the said imaging unit. FIG. 10 is a perspective view showing an overall configuration of a coordinate input device according to another embodiment of the coordinate input device of the present invention. The modification of the coordinate input device in this invention is shown, Comprising: It is a top view which shows the whole structure of a coordinate input device. (A) is a perspective view which shows the structure of the position detection apparatus as a conventional coordinate input device, (b) is a top view which shows the structure of the principal part of the said position detection apparatus. (A) is a top view which shows the detection principle of the position detection apparatus as the said conventional coordinate input device, (b) is a wave form diagram which shows the optical signal of the light receiving element in the said position detection apparatus.

[Embodiment 1]
One embodiment of the present invention will be described below with reference to FIGS.

(Configuration of coordinate input system)
A configuration of a coordinate input system including the coordinate input device according to the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view showing the configuration of the coordinate input system.

  As shown in FIG. 1, the coordinate input system 1 of the present embodiment includes a liquid crystal display panel 2 as an image display panel, and a coordinate input device 3 </ b> A provided on the upper side of the liquid crystal display panel 2.

  The liquid crystal display panel 2 has a liquid crystal layer sandwiched between a pair of substrates (not shown), and each substrate is provided with at least various electrodes for changing the orientation of liquid crystal molecules of 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.

  In the coordinate input system 1, for example, a finger 6 as a detected object is placed on a light guide plate 10 (to be described later) of a coordinate input device 3 </ b> A provided on the upper side of the liquid crystal display panel 2 while viewing the screen displayed on the liquid crystal display panel 2. By touching, the coordinates of the contact position on the finger 6 are specified, and desired data can be input.

(Configuration of coordinate input device)
Next, the configuration of the coordinate input device 3A provided in the coordinate input system 1 will be described in detail below based on FIG. 1 and FIG. FIG. 2 is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 1, the coordinate input device 3 </ b> A includes a light guide plate 10 as a rectangular transparent light guide member, and imaging units 20 and 30 as light receiving means disposed at both ends of one side of the light guide plate 10. And a light source unit 4 as a light source provided around the three sides of the light guide plate 10 and a detection unit 5 as detection means.

  The light guide plate 10 is made of a single flat plate made of a translucent material, and is disposed so as to overlap the display surface side of the liquid crystal display panel 2. The size of the light guide plate 10 is a quadrangle having substantially the same size as the liquid crystal display panel. Specifically, as shown in FIG. 1, one side where the imaging units 20 and 30 are disposed is configured to be larger than the liquid crystal display panel 2. Accordingly, at least a part of the imaging units 20 and 30 can be disposed on the back side of the light guide plate 10. As a result, an increase in the size of the coordinate input device 3A in the direction of spreading along the contact surface of the finger 6 with the light guide plate 10 is suppressed, contributing to the realization of a compact size of the coordinate input device 3A.

  In addition, notches 11 as concave conical surface light path conversion portions are formed at two corners of the light guide plate 10 where the imaging units 20 and 30 are disposed. The angle (γ shown in FIG. 2) formed by the conical surface of the notch 11 and the back surface of the light guide plate 10 is 45 degrees or less, and 30 degrees or 45 degrees is selected. The conical notch 11 is provided with a mirror coating 11a. As a result, as shown in FIG. 2, the optical path of light propagating through the inside of the light guide plate 10 to the notch 11 is changed by the notch 11 below the light guide plate 10, that is, toward the back surface of the light guide plate 10. Let Even without the mirror coating 11 a, the optical path can be changed below the light guide plate 10 by the conical surface of the notch 11. That is, the light guide plate 10 does not have to be a perfect quadrangle, and may be a substantial quadrangle such that corners are notched or corners are curved as described above.

  In this embodiment, since the light conversion member is provided as the notch 11 in the corner portion of the light guide plate 10, the light conversion member is prevented from protruding from the light guide plate 10.

  The thickness of the light guide plate 10 is mainly 1 to 3 mm. However, it may be thicker than this. In the present embodiment, the thickness is 2 mm, for example. As a material of the light guide plate 10, for example, acrylic is used, and polycarbonate or glass may be used. Further, the size of the quadrilateral of the light guide plate 10 can be, for example, about 1 m square, but is not limited thereto.

  The imaging units 20 and 30 are arranged immediately below the conical cutout 11 of the light guide plate 10. In other words, the imaging units 20 and 30 are disposed at two locations separated from each other at the end of the light guide plate 10. In addition, the imaging units 20 and 30 do not protrude above the surface of the light guide plate 10.

  The imaging unit 20 includes a lens 21, a visible light cut filter 22, and an imaging element 23. Similarly, the imaging unit 30 includes a lens 31, a visible light cut filter 32, and an imaging element 33. The image sensors 23 and 33 according to the present embodiment are constituted by, for example, a two-dimensional image sensor. However, the image sensor is not necessarily limited to two dimensions, and may be a one-dimensional image sensor.

  The light receiving surfaces of the image sensors 23 and 33 are arranged so as to be parallel to the surface of the light guide plate 10.

  The imaging units 20 and 30 are connected to the light guide plate 10 and have a structure in which light that does not propagate through the light guide plate 10 is not coupled to the imaging elements 23 and 33.

  In the present embodiment, the notch 11 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.

  Next, in the present embodiment, a light source unit 4 as a light source is provided around the light guide plate 10.

  That is, in the coordinate input device 3A, a light source unit 4 as a light source in which a plurality of LEDs (light emitting diodes) 4a that allow light to enter the light guide plate 10 are arranged around the three sides of the light guide plate 10. It is provided along the side. These three sides are three sides different from one side of the light guide plate 10 provided with the imaging units 20 and 30 at both ends. As a result, the light source unit 4 on the three sides of the light guide plate 10 faces the imaging units 20 and 30, and the imaging units 20 and 30 are provided within the illumination range of the illumination light from the light source unit 4. It will be. In the present invention, it is not necessarily limited to the periphery of the three sides of the light guide plate 10, for example, the periphery of another side different from the one side of the light guide plate 10 provided with the imaging units 20 and 30 at both ends. Good.

  A plurality of LEDs 4 a arranged in the light source unit 4 emit light such as infrared light. However, it is not necessarily limited to infrared light, and may be visible light or ultraviolet light. Further, it is not always necessary to use the LED 4a, and an LD (laser diode) or the like can also be used.

  Next, as shown in FIG. 1, the coordinate input device 3 </ b> A is provided with a detection unit 5 as detection means. The detection unit 5 detects a decrease in output intensity of the imaging elements 23 and 33 based on light scattering by the finger 6 and obtains coordinates of a contact position of the finger 6 on the surface of the light guide plate 10. Specifically, it consists of a CPU.

  Here, in the coordinate input system 1 of this Embodiment, the finger | toe 6 is used as a to-be-detected body, for example. However, the detection target is not necessarily limited to the finger 6 and may be a detection target such as a stick-shaped touch pen.

(Coordinate detection principle of coordinate input device)
The coordinate detection principle when the finger 6 is brought into contact with the light guide plate 10 in the coordinate input device 3A having the above configuration will be described below with reference to FIGS. 3A is a plan view showing an output image of the image sensor 23 when the finger 6 is not in contact with the light guide plate 10, and FIG. 3B is a view when the finger 6 is in contact with the light guide plate 10. 3 is a plan view showing an output image of an image sensor 23. FIG.

  First, in the coordinate input device 3A, light is incident on the light guide plate 10 from a plurality of LEDs 4a provided along the periphery of at least one side of the light guide plate 10 as shown in FIGS.

  The light incident on the light guide plate 10 is guided as propagating light inside the light guide plate 10, and is emitted to the image pickup devices 23 and 33 provided at least at two locations via the notches 11. Thereby, in the image pick-up element 23, as shown to Fig.3 (a), the output image of the fan-shaped bright part 23a based on the shape of the notch 11 is obtained. In FIG. 3A, only the output image of the image sensor 23 is shown, but the output image of the image sensor 33 is the same.

  In this state, when the finger 6 as the detected body is brought into contact with the surface of the light guide plate 10, the propagation light at the contact position is disturbed. As a result, the intensity of light received by the image sensors 23 and 33 is reduced. Specifically, as shown in FIG. 3B, a linear dark part 23b is generated in the bright part 23a. Therefore, by detecting the dark part 23b indicating the decrease in the intensity of the received light amount in the imaging elements 23 and 33, the detection unit 5 can obtain the coordinates of the contact position of the finger 6 on the surface of the light guide plate 10. When the image sensors 23 and 33 are one-dimensional image sensors, dot images appear.

  This detection principle will be described in detail.

As shown in FIG. 2, infrared light enters the light guide plate 10 having a refractive index N from one LED 4 a provided at an end portion of the light guide plate 10 whose surrounding is air. Of this incident light, the propagation angle θ _P in the light guide plate 10 is
sin (90 ° −θ _P )> 1 / N
The light beam satisfying the condition (total reflection condition) is confined in the light guide plate 10, is repeatedly reflected on the front and back surfaces of the light guide plate 10, and travels in the light guide plate 10.

Here, when a substance having a refractive index Nm contacts the surface of the light guide plate, the total reflection condition is:
sin (90 ° −θ _P )> Nm / N
Therefore, part of the light cannot satisfy the total reflection condition and is not confined in the light guide plate 10, and the part of the light is incident on the material side having the refractive index Nm. For example, since the refractive index of human skin is about 1.37, the amount of light trapped in the light guide plate 10 is reduced when the finger 6 contacts the light guide plate 10.

  That is, if the finger 6 does not contact the light guide plate 10, the illumination light in the light guide plate 10 is totally reflected at the contact position of the finger 6 and is incident on the image pickup elements 23 and 33. Due to the light scattering due to the presence, the amount of propagating light toward the image sensors 23 and 33 decreases. As a result, as shown in FIG. 3B, a linear dark portion 23b appears in the output image that is the fan-shaped bright portion 23a shown in FIG. Therefore, based on the dark portion 23b, the coordinates of the contact position of the finger 6 on the surface of the light guide plate 10 can be obtained by the detection unit 5 as described later. 3B shows only the output image of the image sensor 23, the output image of the image sensor 33 is the same.

(Calculation method of 2D coordinate position)
Based on the dark portions 23b of the image sensors 23 and 33 detected as described above, the calculation method of the two-dimensional coordinate position at the location where the finger 6 is in contact with the detection unit 5 will be described with reference to FIGS. A description will be given below based on a) and (b). FIG. 4A is a perspective view showing an imaging state in the imaging unit 20 in the coordinate input device 3A, and FIG. 4B is a plan view showing an image on the imaging element 23 of the imaging unit 20. FIG.

  First, in the present embodiment, triangulation is performed using the angle formed by the imaging units 20 and 30 and the distance between the imaging elements 23 and 33 in the two-dimensional plane of the light guide plate 10 at the place where the finger 6 is in contact. The two-dimensional coordinate position at the location where the finger 6 is in contact is calculated by the method.

  First, detection of an output image on the image sensors 23 and 33 when the finger 6 is not in contact with the light guide plate 10 will be described.

First, as shown in FIG. 2, infrared light enters the light guide plate 10 having a refractive index N from one LED 4 a provided at the end of the light guide plate 10. Of this incident light, the propagation angle θ _P in the light guide plate 10 is
sin (90 ° −θ _P )> 1 / N
The light flux that satisfies the conditions shown in FIG. 5 is confined in the light guide plate 10, and is repeatedly reflected on the front and back surfaces of the light guide plate 10, and travels in the light guide plate 10.

  Here, as shown in FIG. 1, propagating lights 10 a and 10 b in a part of the light flux are also guided to the end faces of the conical cutouts 11 and 11, and the reflected light from the end faces is reflected by the imaging unit 20. • Light is received at 30. Specifically, the reflected light of the end faces of the notches 11 and 11 is collected by the lenses 21 and 31, and then passes through the visible light cut filters 22 and 32 and finally received by the image sensors 23 and 33. Is done. The visible light cut filters 22 and 32 transmit light in the wavelength band emitted by the LED 4a, and play a role of blocking light in other wavelength bands. Visible light cut filters 22 and 32 block stray light such as sunlight and backlight light for a liquid crystal display panel, thereby increasing the SN ratio.

  Next, as illustrated in FIG. 4A, the light incident on the imaging unit 20 forms a linear image on the imaging element 23 through the lens 21. Here, a plurality of LEDs 4a... Exist and enter the light guide plate 10 from a wide range of angles. For this reason, as shown by the alternate long and short dash line in FIG. 4B, a plurality of linear images are gathered on the image sensor 23 to form a fan shape, and as shown in FIG. It appears as an output image of the part 23a.

Next, in this state, as shown in FIG. 4 (a), the detection will be described of the output image on the imaging element 23, 33 when the finger 6 which is in contact with the position of for example the point P ₁ in the light guide plate 10.

In this case, as shown in FIG. 2, by contact of the light guide plate 10 of the finger 6, the light propagation angle theta _P of the light guide plate 10 is disturbed, as a result, amount of light is Genchijimi. The propagating light 10a with the light amount reduced is guided to the end face of the conical cutout 11, and the reflected light of the end face is received by the imaging unit 20. The light incident on the imaging unit 20 via the lens 21, as shown in FIG. 4 (b), to form a linear image of the dark portion BL ₁ in the fan-shaped light portion 23a in the image pickup device 23 .

Further, the finger 6 when moved to the position of the point P _2, the image of the linear dark portion BL ₂ is formed.

The positions of the linear dark portions BL ₁ and BL ₂ shown in FIG. 4B change depending on the position of the contact point on the finger 6. If the position of the contact point of the finger 6 is changed, the linear dark portion BL is changed. ₁ of the image changes as the image of the linear dark portion BL _2. The locus of the images of the linear dark portions BL ₁ and BL ₂ exists inside the fan-shaped bright portion 23a indicated by the alternate long and short dash line. The inclination angle α ₁ ′ of the line segment connecting the fan-shaped center and the image of the linear dark part BL ₁ (with the center of the arc as the center of rotation) The angle is the same as the angle α ₁ formed by one side of the imaging units 20 and 30 side. Therefore, the inclination angle α ₁ ′ is obtained from the acquired image of the image sensor 23, and the angle α ₁ is obtained from the inclination angle α ₁ ′. Similarly, when the finger 6 is moved to the position of the point P _2, the image of the linear dark portion BL ₂ is formed, by obtaining the inclination angle alpha _{2 'in} its linear dark portion BL ₂ of the image, the angle alpha ₂ Is required.

  Similarly, for the image sensor 23, the position of the contact point of the finger 6 is specified from the analysis of the acquired image, and a line segment connecting the finger 6 and the image sensor 23 is formed by one side of the light guide plate 10 on the image pickup unit 20 or 30 side. An angle β is determined.

Then, the interval between the image sensor 23 and the image sensor 33 is L, the angle of the contact point obtained by reading the image from the image sensor 23 is α, and the angle of the contact point obtained by reading the acquired image from the image sensor 23 is obtained. Where β is the coordinate (X, Y) of the contact point, the following relational expression (1) and relational expression (2)
Y = tan α · X (1)
Y = tan β · (L−X) ... Relational expression (2)
Satisfied. Solving this, the coordinates (X, Y) of the contact point are
X = tan β · L / (tan α + tan β) Equation (3)
Y = (tan α · tan β) · L / (tan α + tan β) (4)
The coordinates X · Y of the point where the finger 6 touches are obtained from the angles α · β obtained as described above and the interval L that can be obtained in advance. Among these, the space | interval L is a space | interval between the image pick-up element 23 and the image pick-up element 33, and is a fixed value. Therefore, by obtaining the angles α and β, the coordinates X and Y of the contact position of the finger 6 can be obtained.

  The distance L between the image sensor 23 and the image sensor 33 is a distance between the optical axis center of the lens 21 and the optical axis center of the lens 31.

  Based on the contact position coordinates of the finger 6 obtained by the above method, the user can visually recognize the touch position of the finger 6 by driving a pixel at a position corresponding to the position coordinate of the liquid crystal display panel 2. It is possible to make it possible. For this purpose, a control unit (not shown) that controls driving of the liquid crystal display panel 2 may acquire information on the position coordinates obtained by the position coordinate detection unit and drive the liquid crystal display panel 2 based on the information.

  As described above, the coordinate input device 3 </ b> A of the present embodiment includes the plate-shaped light guide plate 10, the light source unit 4 that makes the illumination light incident from the end of the light guide plate 10, and the illumination light that propagates in the light guide plate 10. Based on the outputs of the imaging units 20 and 30 that detect light scattering by the finger 6 when the finger 6 comes into contact with the surface of the light guide plate 10 and at least two imaging units 20 and 30 that receive light, the light guide plate 10 in the finger 6. And a detection unit 5 for obtaining coordinates of a position of contact with the surface.

  Here, in the touch panel of Patent Document 1, the light reception peak of scattered light due to the presence of the detection target is detected in a state where the light reception amount of the light receiving means is maintained at zero. As a result, if the light receiving means is not arranged outside the irradiation range of the light source, the amount of light received by the light receiving means cannot be maintained at 0, and the amount of scattered light received by the detected object is very small. In the contact detection of the object to be detected at a distance from the means, the signal quality is lowered, and it is difficult to apply to a large touch panel.

  Therefore, in the present embodiment, the imaging units 20 and 30 as light receiving means are provided within the illumination light irradiation range, and the detection unit 5 includes the imaging units 20 and 30 based on light scattering by the finger 6. The decrease in output intensity is detected, and the coordinates of the contact position of the finger 6 on the surface of the light guide plate 10 are obtained.

  That is, in the present embodiment, the idea is changed with respect to Patent Document 1, and in Patent Document 1, the received light peak of scattered light due to the presence of the detected object is detected, whereas in the present embodiment, In a state where a certain amount of received light is given to the imaging units 20 and 30 from the beginning, a decrease in output intensity in the imaging units 20 and 30 is detected based on light scattering due to the presence of the finger 6.

  As a result, since the imaging units 20 and 30 are provided within the illumination light irradiation range, the imaging units 20 and 30 are constantly given a constant amount of received light, and in that state, far from the imaging units 20 and 30. Due to the light scattering caused by the contact of the finger 6 at this point, the intensity is reduced in the constant amount of received light. For this reason, by detecting this strength reduction, the coordinates of the contact position of the finger 6 on the surface of the light guide plate 10 can be obtained by the detection unit 5.

  Therefore, even when the optical coordinate input device 3A using the light guide plate 10 is applied to a large touch panel, the coordinate input device 3A that can detect the coordinate position of the detected object such as the finger 6 can be provided. .

  In the coordinate input device 3 </ b> A of the present embodiment, the imaging units 20 and 30 have a one-dimensional or two-dimensional image sensor, and the light guide plate 10 has illumination light propagating through the light guide plate 10. Are provided in the image capturing units 20 and 30 in a dotted or linear manner.

  Thereby, the illumination light propagating in the light guide plate 10 and the attenuated light by the finger 6 are respectively emitted to the outside of the light guide plate 10 through the notches 11, and are respectively supplied to the image pickup devices 23 and 33 of the image pickup units 20 and 30. It is emitted in the form of dots or lines.

  For this reason, in each imaging unit 20, 30, since the interval between each imaging unit 20, 30 in the triangle connecting each imaging unit 20, 30 and the contact position of the finger 6 to the light guide plate 10 and two angles are known, The detection unit 5 can obtain the coordinates of the contact position of the finger 6 with the light guide plate 10 by triangulation.

  Accordingly, the coordinate input device 3A is used which uses the light guide plate 10 and obtains the coordinates of the contact position of the finger 6 with the light guide plate 10 by triangulation by light scattering due to the contact of the finger 6 with the light guide plate 10. be able to.

  The coordinate input system 1 of the present embodiment is a coordinate input system including the coordinate input device 3A of the present embodiment, and includes a liquid crystal display panel 2.

  Thereby, coordinate input device 3A can be functioned as a touch panel which inputs with a detected object, such as finger 6, while seeing an image of liquid crystal display panel 2. Therefore, in the optical coordinate input device 3A using the light guide plate 10, even when applied to a large touch panel, the coordinate input system provided with the coordinate input device 3A that can detect the coordinate position of the detected object such as the finger 6 or the like. 1 can be provided.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIGS. The configurations other than those described in the present embodiment are the same as those in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment are given the same reference numerals, and explanation thereof is omitted.

  In the coordinate input device 3A of the first embodiment, two imaging units 20 and 30 as light receiving means are provided.

  However, the coordinate input device 3B according to the present embodiment is different in that three or more imaging units 20, 30 and 40 as light receiving means are provided as shown in FIG. As a result, it is possible to detect the fingers 6A and 6B as the two detection objects.

  That is, for example, as shown in FIG. 5, when there are two fingers 6A and 6B as detection objects, and there are only two imaging units 20 and 30 as light receiving means, the two fingers 6A and 6B When the optical paths overlap, the linear dark portion BL also overlaps, so it is not possible to specify which of the two fingers 6A and 6B is present.

  However, as shown in FIG. 5, if there are three imaging units 20, 30, and 40 as light receiving means, the imaging units 20, 30, and 40 with two optical paths that do not overlap each finger 6 </ b> A and 6 </ b> B. It is possible to obtain the contact position of each finger 6 by using it. The imaging unit 40 includes a lens 41, a visible light cut filter 42, and an imaging element 43.

Specifically, for example, in FIG. 5, when the finger 6B is present at point P _3, overlaps the optical path of the finger 6B finger 6A to the imaging unit 20. In this case, two imaging units 30 and 40 are used to detect the finger 6A, while the imaging units 20 and 40 are used to detect the finger 6B. As a result, the optical paths do not overlap.

  Therefore, even if the two fingers 6A and 6B are brought into contact with any place on the light guide plate 10, the position coordinates of the contact points of the fingers 6A and 6B can be reliably specified.

In general, when there are M fingers 6 as detection objects, the required number N of light receiving means is:
N = M + 1
It becomes.

  On the other hand, when at least three image pickup units 20, 30, and 40 as light receiving means are provided, there are the following merits.

  That is, when there are two light receiving means, that is, the imaging units 20 and 30, when the finger 6A comes into contact with the vicinity of the side of the light guide plate 10 on which the two imaging units 20 and 30 are provided, a blind spot is formed. There is a possibility that the image pickup units 20 and 30 may not detect them. In this case, if there are three light receiving means, for example, if they are arranged at the apex of a triangle, the finger 6A can be brought into contact with any location of the light guide plate 10 without generating a blind spot. The position coordinates of the contact point of the finger 6A can be reliably specified.

  In this case, for example, as shown in FIG. 6, the imaging units 20, 30, 40, and 50 as the light receiving means can be disposed at four corners of the rectangular light guide plate 10. In the present invention, three image pickup units 20, 30, 40 as light receiving means may be used.

  Here, when the four image pickup units 20, 30, 40, and 50 as the light receiving means are arranged at the respective corners of the rectangular light guide plate 10, as shown in FIG. It is preferable that the units 4... Be arranged at the end of the entire periphery of the light guide plate 10 and the light source units 4... Be the coordinate input device 3 </ b> C that allows illumination light to enter from the end of the entire periphery of the light guide plate 10. . As a necessary condition, when the number of imaging units 40 and 50 as light receiving means is increased around the light guide plate 10, it is preferable that a light source exists at a position opposite to the imaging units 40 and 50.

  As a result, the four imaging units 20, 30, 40, and 50 as the light receiving means are all provided in the illumination light irradiation range in the light guide plate 10. Therefore, it is possible to reliably specify the position coordinates of the contact point of the finger 6A, regardless of where the finger 6A is in contact with the light guide plate 10.

  In addition, since the light source units 4 and the imaging units 20, 30, 40, and 50 are arranged to face each other, the degree of freedom in arranging the imaging units 20, 30, 40, and 50 is increased. In addition, the number of image pickup units 20, 30, 40, 50 can be easily increased, and simultaneous detection of contact with a large number of fingers 6A, 6B, etc. is possible, resulting in a decrease in signal quality when applied to a large touch panel. hard.

  Here, when four image pickup units 20, 30, 40, and 50 are provided, any two of the four image pickup units 20, 30, 40, and 50 are used for detection of the finger 6A. can do.

  However, for example, when the imaging units 20 and 30 are arranged along one side of the light guide plate 10, the signal quality is deteriorated when the contact point of the finger 6A is far from the imaging units 20 and 30. Therefore, when the contact point of the finger 6A is far from the imaging units 20 and 30, by increasing the number of imaging units 40 and 50 as light receiving means around the light guide plate 10, the imaging units 40 and 50 close to the finger 6A can be connected. By detecting this, it is possible to detect without degrading the signal quality.

  The determination of whether or not they are close can be made based on whether the signal attenuation is large or small. In other words, it can be said that the closer the signal attenuation, the closer.

  As described above, in the coordinate input device 3B of the present embodiment, at least three light receiving units are provided as the imaging units 20, 30, and 40.

  As a result, the contact positions of the fingers 6A and 6B can be obtained for the fingers 6A and 6B by using the imaging units 30 and 40 and the imaging units 20 and 40 by two optical paths that do not overlap each other.

  Further, by arranging the three imaging units 20, 30 and 40 at the apexes of the triangle, the finger 6A can be brought into contact with any position of the light guide plate 10 without generating a blind spot. It is possible to reliably specify the position coordinates of the point.

  Furthermore, in the coordinate input device 3 </ b> C according to the present embodiment, the light source unit 4 causes illumination light to enter from the entire peripheral end of the light guide plate 10. Thereby, the imaging units 20, 30, 40, and 50 have the entire range in the light guide plate 10 within the illumination light irradiation range.

  Therefore, it is possible to reliably specify the position coordinates of the contact point of the finger 6A, regardless of where the finger 6A is in contact with the light guide plate 10.

  It should be noted that the present invention is not limited to each embodiment, and various modifications are possible within the scope shown in the claims, and obtained by appropriately combining the technical means disclosed in each embodiment. Such embodiments are also included in the technical scope of the present invention.

  The present invention includes a plate-shaped light guide member, a light source that makes illumination light incident from an end of the light guide member, at least two light receiving means that receive illumination light propagating in the light guide member, and the light guide member. Detecting means for obtaining coordinates of a contact position of the light guide member on the surface of the detected body based on an output of the light receiving means that detects light scattering by the detected body when the surface of the detected object is contacted The present invention can be applied to an optical coordinate input device and a coordinate input system. Further, the coordinate input device can be applied to both a finger type and a touch pen type.

1 Coordinate input system 2 Liquid crystal display panel (image display panel)
3A Coordinate input device 3B Coordinate input device 3C Coordinate input device 4 Light source unit (light source)
4a LED
5 Detection part (detection means)
6 fingers (detected body)
10 Light guide plate (light guide member)
10a Propagating light 10b Propagating light 11 Notch (optical path changing unit)
20 Imaging unit (light receiving means)
21 Lens 22 Visible Light Cut Filter 23 Imaging Device 23a Bright Part 30 Imaging Unit (Light Receiving Unit)
31 Lens 32 Visible Light Cut Filter 33 Imaging Device 40 Imaging Unit (Light Receiving Unit)
50 Imaging unit (light receiving means)
BL Dark part BL ₁ Dark part BL ₂ Dark part L Interval

Claims (5)

A plate-shaped light guide member, a light source for making illumination light incident from an end of the light guide member, at least two light receiving means for receiving illumination light propagating in the light guide member, and a surface of the light guide member Coordinates comprising detection means for determining the coordinates of the position of the light guide member in contact with the surface of the light guide member based on the output of the light receiving means that has detected light scattering by the object to be detected when contacting the detection body An input device,
The light receiving means is provided within the illumination light irradiation range,
The detection means detects a decrease in output intensity of the light receiving means based on light scattering by the detected object, and obtains coordinates of a position of contact with the surface of the light guide member on the detected object. apparatus.   The coordinate input device according to claim 1, wherein at least three light receiving means are provided.   The coordinate input device according to claim 1, wherein the light source is configured to allow illumination light to enter from an end portion around the entire periphery of the light guide member. The light receiving means has a one-dimensional or two-dimensional image sensor,
4. The light guide member is provided with an optical path changing unit that emits illumination light propagating in the light guide member to the light receiving means in a dotted or linear manner, respectively. The coordinate input device described. A coordinate input system comprising the coordinate input device according to any one of claims 1 to 4,
A coordinate input system comprising an image display panel.

Images