JP2013232095A - 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 which can prevent deterioration in detection accuracy when a viewing angle to an object to be detected from a light receiving section is small while suppressing an increase in cost, and can simultaneously use a plurality of objects to be detected even for any one object to be detected out of a pen and a finger.SOLUTION: A reflection plate 4 which reflects light emitted from a light guide plate 10 thereon and reflects the reflected light on the light guide plate 10 again is provided on the outer periphery of the light guide plate 10. A detection section 7 determines a coordinate of a contact position P of the surface of the light guide plate 10 by a touch pen 40 by output of imaging units 20 and 30 in transmission lights 13a and 14a which are direct light from the touch pen 40, and transmission lights 13b and 13c and transmission lights 14b and 14c that are reflected light by the reflection plate 4.

Description

  The present invention relates to an optical coordinate input device and a coordinate input system that use a detection object such as a finger or a bar-shaped operation member pen such as a touch pen or a stylus pen. Specifically, the present invention relates to a plurality of detection objects. It is related with the identification when using simultaneously.

  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 An 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 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.

  By the way, in this type of coordinate input device, when a plurality of pens or fingers are simultaneously touched on the display panel, there is a problem of how to identify each pen or finger.

  For example, when two light-emitting pens are used and the touch position of each light-emitting pen is detected using the triangulation method, and the viewing direction of each light-emitting pen from the detector matches, each light-emitting pen Cannot be identified.

  Therefore, for example, the coordinate input device 100 disclosed in Patent Document 1 includes two pairs of detectors, a detector L · R and a detector CL · CR, as shown in FIG. Thereby, the coordinate values P1 (x1, y1) and P2 (x2, y2) of each light emitting pen can be detected.

  Further, for example, in the coordinate input device 200 disclosed in Patent Document 2, as shown in FIG. 13, the light emission periods of a plurality of light emitting pens are different from each other. Thereby, a plurality of types of light emitting pens can be distinguished from each other.

JP 2006-031549 A (published February 2, 2006) JP 2011-128991 A (released on June 30, 2011)

  However, the conventional coordinate input device has the following problems.

  That is, the coordinate input device 100 disclosed in Patent Document 1 includes two pairs of detectors L and R and detectors CL and CR in order to use two types of light emitting pens simultaneously. As a result, two pairs of expensive detectors must be prepared, which causes a problem that the cost of the coordinate input device 100 increases.

  Further, in the coordinate input device 200 disclosed in Patent Document 2, it is necessary to control the light emission periods in a plurality of light emitting pens, and to require a period detection unit for detecting different light emission periods. have. Further, when the object to be detected is a finger, since the light emitting pen is not used, there is no room for different light emission periods, and there is a problem that the coordinate positions of a plurality of fingers cannot be detected.

  Further, even when a plurality of detection objects are not used, if the viewing angle from the pair of light receiving units to the detection object is small, the triangulation method has a problem that the detection accuracy is deteriorated.

  The present invention has been made in view of the above-described conventional problems, and its purpose is to prevent a decrease in detection accuracy when the viewing angle from the light receiving unit to the detected object is small while suppressing an increase in cost. In addition, another object of the present invention is to provide a coordinate input device and a coordinate input system that can enable simultaneous use of a plurality of detection objects in either a pen or a finger detection object.

  In order to solve the above problems, a coordinate input device of the present invention includes a plate-shaped light guide member, at least two light receiving means for receiving propagation light propagating in the light guide member, and a surface of the light guide member. Detecting means for obtaining coordinates of a contact position of the detected body with respect to the surface of the light guide member based on an output of the light receiving means that detects propagation light based on the contact when the detected body is contacted In the coordinate input device, a reflection plate that reflects light emitted from the light guide member and re-enters the light guide member is provided on an outer periphery of the light guide member, and the detection unit Is characterized in that the coordinates of the position of contact of the light guide member on the surface of the detected body with the output of the light receiving means in the direct light from the detected body and the reflected light from the reflecting plate are obtained.

  According to the above invention, the coordinate input device includes a plate-shaped light guide member, at least two light receiving means for receiving propagation light propagating through the light guide member, and a detected object on the surface of the light guide member. Detecting means for obtaining coordinates of a contact position on the surface of the light guide member in the detected body based on the output of the light receiving means that detects the propagation light based on the contact when the light is touched.

  In a coordinate input device using this kind of triangulation method, when the contact position of the detected object is a position near the light receiving means in the light guide member, the detection limit is exceeded, so the detection accuracy is low. That is, in the calculation by the triangulation method, if the incident angle to at least one light receiving means with respect to the line connecting the two light receiving means is too acute, the error will increase even if it is calculated, and the detection accuracy will be low. .

  Therefore, in the present invention, in order to avoid the occurrence of such a region where position detection is difficult, the light emitted from the light guide member is reflected on the outer periphery of the light guide member and re-applied to the light guide member. A reflecting plate for incidence is provided. And a detection means calculates | requires the coordinate of the contact position to the surface of the light guide member in a to-be-detected body by the output of the light-receiving means in the direct light from a to-be-detected body and the reflected light by the said reflecting plate.

  As a result, even when the viewing angle from the two light receiving means to the detected object is small, the incident angle of the reflected light to the light receiving means via the reflector increases.

  In addition, this configuration does not increase the number of expensive detection units, so that it is possible to suppress an increase in cost and, as will be described later, a plurality of detection objects in any detection object of a pen or a finger. Can be easily identified when they are used simultaneously.

  Therefore, while suppressing an increase in cost, it is possible to prevent a decrease in detection accuracy when the viewing angle from the light receiving means to the detected object is small, and in addition, a plurality of detected objects such as a pen or a finger It is possible to provide a coordinate input device that can enable simultaneous use in a detection object.

  In the coordinate input device of the present invention, the plate-shaped light guide member has a square shape, and the at least two light receiving means are provided in the vicinity of one side of the square light guide member. Is preferably provided on one or both of the outer circumference of one side of the light guide member on the side where the at least two light receiving means are provided, or the outer circumference of the opposite side facing the one side.

  Thereby, when the reflection plate is provided on either the outer periphery of one side of the light guide member on the side where at least two light receiving means are provided or the outer periphery of the opposite side opposite to the one side The viewing angle between the detected object and the light receiving means can be obtained from the propagation light in the two directions of the direct light from the detected object and the reflected light from the reflecting plate. Therefore, even when the viewing angle of the direct light from the two light receiving means to the detected body is small, the viewing angle between the detected body and the light receiving means can be obtained accurately by adopting one reflected light. Can do.

  Further, when the reflection plate is provided on either the outer periphery of one side of the light guide member on the side where at least two light receiving means are provided or the outer periphery of the opposite side opposite to the one side, the detected object The viewing angle between the detected object and the light receiving means can be obtained from the propagating light in three directions of the direct light from the body and the reflected light from the two reflecting plates. Therefore, even when the viewing angle of the direct light from the two light receiving means to the detected body is small, the viewing angle between the detected body and the light receiving means is obtained with higher accuracy by adopting the two reflected lights. be able to.

  In the coordinate input device according to the aspect of the invention, the light guide member is provided with a light extraction portion that extracts propagating light propagating through the light guide member from a direction of 360 degrees below the lower surface of the light guide member. The light receiving means preferably receives the propagating light extracted by the light extraction unit below the lower surface of the light guide member.

  Accordingly, the light extraction unit extracts the propagation light propagating through the light guide member from the direction of 360 degrees below the lower surface of the light guide member. For this reason, the light receiving means can receive the propagating light regardless of which direction the propagating light of the reflected light from the reflecting plate is propagated.

  In the coordinate input device of the present invention, the detected object can be used simultaneously with at least two of the first detected object and the second detected object, and the first detected object and the second detected object. The body includes a light-emitting pen having a light-emitting portion that makes light incident on the light guide member by contacting the surface of the light guide member, and the light receiving means includes the first detected body and the second detected body. It is assumed that light emitted from the light guide member in the first propagation light and the second propagation light that are incident on the light guide member from each light emitting portion of the detected body and propagate through the light guide member is received. it can.

  Thereby, the to-be-detected body consists of the light emitting pen which has the light emission part which makes light incident on this light guide member by contacting the surface of a light guide member. In the present invention, the object to be detected can be used simultaneously with at least two of the first object to be detected and the second object to be detected.

  In such a coordinate input device, when two or more light emitting pens are used at the same time and each light emitting pen uses light of the same wavelength region, two light emitting pens are arranged in the line-of-sight direction of the light receiving means. At this time, since the light emitted from the light emitting pen located behind the light receiving means is blocked by the light emitting pen in front, there is a problem that the position cannot be detected by the triangulation method.

  In order to solve this problem, for example, a pair of first light receiving means and second light receiving means which generate light of different wavelengths for two light emitting pens and which are essential for each light emitting pen, If two sets are prepared, the number of parts of the apparatus increases and the cost increases.

  Here, in the present invention, first, even when two or more light emitting pens that allow light to enter the light guide member are used at the same time, the light receiving means is provided only with at least a pair of light receiving means essential for triangulation. Not.

  In this situation, in order to identify the light emission from each light-emitting pen by the two light receiving means, in the present invention, as described above, the light emitted from the light guide member is reflected and re-applied to the light guide member. A reflection plate to be incident is provided, and the detection unit is configured to contact the surface of the light guide member on the detected body with the output of the light receiving unit in the direct light from the detected body and the reflected light from the reflection plate. Find the coordinates of.

  That is, when two light emitting pens are lined up in the line-of-sight direction of the light receiving means, the direct light emitted from the light emitting pen located in the back as viewed from the light receiving means is blocked by the light emitting pen in front, so that the triangulation method In position detection is not possible. However, even in such a case, the reflected lights of the first detection target and the second detection target do not overlap.

  As a result, even when two light emitting pens are arranged in the line-of-sight direction of the light receiving means, the contact position of the light emitting pen can be easily detected.

  Therefore, even when the detected object is a light emitting pen, it is possible to provide a coordinate input device that can simultaneously use a plurality of detected objects.

  In the coordinate input device of the present invention, the detected object can be used simultaneously with at least two of the first detected object and the second detected object, and the illumination light is emitted from the end of the light guide member. A light source to be incident is provided, and the first detected body and the second detected body come to scatter the illumination light propagating through the light guide member by contacting the surface of the light guide member. The light receiving means includes illumination light propagating in the light guide member, first propagation light that is scattered light by the first detected body, and second propagation light that is scattered light by the second detected body. And detecting the change in the output intensity of the light receiving means based on the scattering of the illumination light due to the contact of the first detected body and the second detected body with the light guide member, The contact position of the first detected body and the second detected body to the surface of the light guide member You may be seeking target.

  Thereby, the detected object is made of, for example, a finger, and scatters illumination light propagating through the light guide member by contacting the surface of the light guide member. In the present invention, the object to be detected can be used simultaneously with at least two of the first object to be detected and the second object to be detected.

  In such a coordinate input device, when two or more objects to be detected are used at the same time and two or more objects to be detected are arranged in the line-of-sight direction of the light receiving means, the detected object is located behind the light receiving means. Because the direct light of the light propagating from the light and the direct light of the propagating light from the object to be detected in the foreground form an image at the same position of the light receiving means, which is behind in the triangulation method? The problem that it cannot be detected occurs.

  Here, in the present invention, first, even when a plurality of detection objects such as fingers are used at the same time, the light receiving means is provided with only at least a pair of light receiving means essential in the triangulation method.

  In this situation, in order to identify the light emission from each light-emitting pen by the two light receiving means, in the present invention, as described above, the light emitted from the light guide member is reflected and re-applied to the light guide member. A reflection plate to be incident is provided, and the detection unit is configured to contact the surface of the light guide member on the detected body with the output of the light receiving unit in the direct light from the detected body and the reflected light from the reflection plate. Find the coordinates of.

  That is, when two detection objects such as fingers are arranged in the line-of-sight direction of the light receiving means, direct light emitted from the detection objects located in the back as viewed from the light receiving means is blocked by the detection objects in front. Therefore, the position cannot be detected by the triangulation method. However, even in such a case, the reflected lights of the first detection target and the second detection target do not overlap.

  As a result, even when two detected objects such as fingers are arranged in the line-of-sight direction of the light receiving means, the contact position of the detected object can be easily detected.

  Accordingly, it is possible to provide a coordinate input device that can enable simultaneous use of a plurality of detection objects even when the detection object includes a detection object that does not use a light emitting pen such as a finger.

  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 touch panel which performs pen input and finger input, seeing the image of an image display panel. Therefore, while suppressing an increase in cost, it is possible to prevent a decrease in detection accuracy when the viewing angle from the light receiving means to the detected object is small, and in addition, a plurality of detected objects such as a pen or a finger It is possible to provide a coordinate input system including a coordinate input device that can enable simultaneous use in a detection object.

  As described above, in the coordinate input device of the present invention, the outer periphery of the light guide member is provided with the reflector that reflects the light emitted from the light guide member and re-enters the light guide member. The detecting means obtains the coordinates of the contact position of the light guide member on the surface of the detected body with the output of the light receiving means in the direct light from the detected body and the reflected light from the reflecting plate.

  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, while suppressing an increase in cost, it is possible to prevent a decrease in detection accuracy when the viewing angle from the light receiving means to the detected object is small, and in addition, a plurality of detected objects of either a pen or a finger are used. It is possible to provide a coordinate input device and a coordinate input system that can be used simultaneously in the detected object.

1 is a plan view illustrating a configuration of a coordinate input device according to an embodiment of a coordinate input device according to the present invention. It is a perspective view which shows the whole structure of the coordinate input system provided with the said coordinate input device. It is a principal part top view which shows the structure of the through-hole vicinity in the light-guide plate of the said coordinate input device. FIG. 3 shows a configuration of an imaging unit of the coordinate input device, and is a cross-sectional view taken along line AA in FIG. 3. FIG. 4 is a cross-sectional view taken along line B-B in FIG. 3, showing an optical path of propagation light in the light guide plate of the coordinate input device. It is a top view which shows the position of the through-hole in the said light-guide plate. It is a top view which removes and shows the housing | casing of the upper surface in the touch pen of the said coordinate input device. (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. 7 is a perspective view showing an overall configuration of a coordinate input system including a coordinate input device according to another embodiment of the coordinate input device and the coordinate input system of the present invention. It shows the whole structure of the said coordinate input system, Comprising: It is CC sectional view taken on the line of 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. It is a top view which shows the structure of the conventional coordinate input device. It is a chart which shows the structure of the other conventional coordinate input device, Comprising: The light emission timing of a light emission touch pen.

[Embodiment 1]
One embodiment of the present invention is 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. 2 is a perspective view showing the configuration of the coordinate input system.

  As shown in FIG. 2, 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 3A as a coordinate input device provided on the upper side of the liquid crystal display panel 2. It has.

  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, a touch pen 40 as a detection 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 watching the screen displayed on the liquid crystal display panel 2. By making contact, the coordinates of the contact position on the touch pen 40 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 with reference to FIG.

  As shown in FIG. 2, 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 on both ends of one side of the light guide plate 10. And a touch pen 40 as a light-emitting pen that is in contact with the light guide plate 10.

  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. 2, 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 extending along the contact surface to the light guide plate 10 in the touch pen 40 is suppressed, which contributes to the realization of the compact size of the coordinate input device 3A. In the present embodiment, the light guide plate 10 is made of a rectangular plate material. However, in the present invention, the light guide plate 10 is not necessarily limited to a square shape. Further, the four corners of the light guide plate 10 may not be a right angle, and may be, for example, an arc shape.

  Further, in the vicinity of both ends of the light guide plate 10 near one side where the imaging units 20 and 30 are disposed, through holes 11 are provided as light extraction portions penetrating from the touch surface to the back surface.

  Here, the details of the through hole 11 and the imaging unit 20 will be described with reference to FIGS. 3 is a partially enlarged plan view showing the through-hole 11 and its periphery, and FIG. 4 is a cross-sectional view taken along the line AA in FIG. 5 is a cross-sectional view taken along line BB in FIG. In addition, since the two through-holes 11 and 11 provided on both sides in the vicinity of one side of the light guide plate 10 have the same structure and the imaging units 20 and 30 have the same structure, respectively, in FIGS. For convenience of explanation, one of the two through-holes 11, 11 provided in the light guide plate 10 and one imaging unit 20 arranged below the through-hole 11 will be described, and the other one through-hole 11 and the imaging unit 30 will not be described.

  As shown in FIGS. 3 and 4, the through hole 11 is configured such that the opening diameter on the touch surface side of the light guide plate 10 is larger than the opening diameter on the back surface side, and from the touch surface side toward the back surface side. It has a funnel shape with a continuously decreasing diameter. In other words, the wall surface of the through hole 11 is inclined with respect to the direction perpendicular to the touch surface and the back surface. In the present embodiment, the through hole 11 is not cut out at the end portion of the light guide plate 10, but the through hole 11 is arranged on the inner side of the end portion of the light guide plate 10. 11 is completely included in the light guide plate 10. However, the light extraction portion of the present invention is not necessarily limited to this, and may be cut out at the end portion of the light guide plate 10.

  The imaging unit 20 is disposed immediately below the through hole 11 and its periphery at a position facing the back surface of the light guide plate 10.

  As shown in FIG. 5, the light incident on the light guide plate 10 from the touch pen 40 and combined is propagated through the light guide plate 10 by propagating light 13 a and 14 a while being totally reflected. Then, when reaching the wall surface 11 a of the through hole 11, the optical path of the light is changed by the wall surface 11 a, is directed toward the back surface of the light guide plate 10, is further emitted from the back surface, and is incident on the imaging unit 20.

  Here, the wall surface 11 a of the through hole 11 is inclined with respect to the back surface of the light guide plate 10 at 45 degrees or less, for example, 30 degrees or 45 degrees. As a result, it is possible to break down the total reflection condition of the light propagating through the light guide plate 10 and reaching the wall surface 11 a of the through hole 11. For example, the wall surface 11a of the through-hole 11 allows light that has propagated through the light guide plate 10 to reach the wall surface to change by 90 degrees toward the back surface of the light guide plate 10 and to be emitted further downward from the back surface. it can.

  The funnel-shaped wall surface 11a in the through hole 11 may be mirror coated. By performing mirror reflection and light reflection processing, the optical path can be more effectively converted, and the loss of light quantity can be suppressed.

  As shown in FIG. 5, the imaging unit 20 includes a lens 21, a visible light cut filter 22, and an imaging element 23 in this order from the light incident side of the propagation light 13a. Therefore, the light incident on the imaging unit 20 is first condensed by the lens 21, and then the visible light is blocked by the visible light cut filter 22 and received by the imaging element 23. In the image sensor 23, the received light is photoelectrically converted to form an image. This point will be described later.

  In the present embodiment, the imaging unit 20 is fixed to the light guide plate 10. Specifically, as shown in FIG. 4, the imaging unit 20 and the light guide plate 10 are fixed via a fixing member 20a and an adhesive 20b.

  The fixing member 20a has a cylindrical structure. However, the structure is not limited to this, and the size is not particularly limited. However, it is preferable that it is compact and has sufficient strength. The type of the adhesive 20b is not particularly limited, and a conventionally known adhesive can be used.

  By the way, in this Embodiment, as shown in FIG. 2, the imaging units 20 and 30 are distribute | arranged inside the edge part of the light-guide plate 10. As shown in FIG. Therefore, a part of the entire area on the upper surface of the light guide plate 10 is a coordinate detectable area. Therefore, in the present embodiment, the fixing positions of the imaging units 20 and 30 to the light guide plate 10 are defined using this.

  Below, the fixing position of the imaging units 20 and 30 to the light guide plate 10 will be described with reference to FIG. FIG. 6 is a plan view showing the positions of the through holes 11 and 11 in the light guide plate 10.

  As shown in FIG. 6, the coordinate detectable region 10 a of the light guide plate 10 is a region that narrows from the end of the upper surface of the light guide plate 10 toward the center of the upper surface. In the coordinate detectable region 10a, light propagates and is totally reflected as described above. Therefore, in the coordinate detectable region 10a, the fixing member 20a and the adhesive 20b are located at positions outside the coordinate detectable region 10a. This is preferable because, for example, even when bubbles are included during the formation of the adhesive 20b, the above-described total reflection condition is not broken and detection of position coordinates is not hindered. In other words, when the adhesive 20b is provided in the coordinate detectable region 10a, if there are bubbles in the adhesive 20b, the total reflection condition may break down and the propagation light may leak. In particular, among the areas outside the coordinate detectable area 10a, the non-light-receiving area 10b outside the light-receiving capable area where the imaging units 20 and 30 can receive the propagating light propagated through the light guide plate 10 (in the drawing) It is desirable to provide the fixing member 20a and the adhesive 20b in the hatched portion. If it is the outside light receiving region 10b, the propagation light is not disturbed. Here, the light receivable region is closest to each of the through holes 11 and 11 at the center of each of the two through holes 11 and 11 provided in the light guide plate 10 and the four corners of the rectangular coordinate detectable region 10a. An area closer to the coordinate detectable area 10a than a straight line connecting two corners adjacent to the corner.

  The imaging unit 30 shown in FIG. 2 has the same configuration as that of the imaging unit 20 shown in FIG. The imaging units 20 and 30 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.

  The thickness of the light guide plate 10 is mainly 1 to 3 mm. As the material of the light guide plate 10, for example, acrylic is used, and polycarbonate or glass may be used. Moreover, although the thickness of the light guide plate 10 is mainly 1 to 3 mm, it may be thicker than this. Furthermore, the size of the light guide plate 10 (the size of the touch surface) can be about 1 m square, but is not limited thereto.

  The through hole 11 has a structure similar to a cone. However, the present invention is not limited to this, and may be configured in a polygonal shape.

  The fixing member 20a and the adhesive 20b described above are bonded to the imaging element 23 on the imaging unit 20 side, but the present invention is not limited to this.

(Configuration of touch pen)
Next, the structure of the touch pen of this Embodiment is demonstrated based on FIG. FIG. 7 is a plan view showing the configuration of the touch pen 40 of the present embodiment. In FIG. 7, for convenience of explanation, a part of the casing is removed to expose the internal structure.

  The touch pen 40 is an operation member called a so-called touch pen or stylus pen.

  As shown in FIG. 7, the touch pen 40 introduces light into the light guide plate 10 from the tip of the touch pen 40 into the light emitting element 42 a that emits light and the light emitted from the light emitting element 42 a inside the casing 41 that forms the outer shape. The light-emitting part 42 which has the introduction part 42b to make, the power supply device 43, and the control apparatus 44 are stored. A light scattering member 45 that diffuses light is fixedly attached to the introduction portion 42b on the light emitting tip side of the touch pen 40.

  The light scattering member 45 is made of a resin containing a light diffusing material. Glass beads can be used as the light diffusion material. Moreover, as said resin, fluororesins, such as polytetrafluoroethylene, or a silicon rubber can be used, for example, and it is preferable to have elasticity. By using the elastic material, when the tip of the touch pen 40, that is, the light scattering member 45 is used in contact with the light guide plate 10 of the coordinate input device 3A, the surface of the light guide plate 10 is not damaged and the contact portion is slightly touched by the contact. Can be deformed to increase the contact area with the surface of the light guide plate 10. As a result, the amount of light introduced to the surface of the light guide plate 10 can be increased. That is, light from the touch pen 40 can be incident in a plurality of radial directions with respect to the depth direction inside the light guide plate 10.

  The light emitting surface of the light scattering member 45 has a curved surface. That is, the light scattering member 45 is generally hemispherical and has a diameter of, for example, 2.5 to 5.5 mm. When the diameter is smaller than 2.5, there is a possibility that the sufficiently diffused light cannot be formed.

  Further, the light scattering member 45 is configured to be detachable from the touch pen 40. Thereby, even if the light scattering member 45 is damaged for some reason or is deteriorated with time, the use of the touch pen 40 can be continued only by replacing the light scattering member 45.

  As the light emitting element 42a, for example, an LED (light emitting diode) or an LD (laser diode) emitting light such as infrared light can be used. Note that the number of LEDs or LDs is not limited to one provided for one touch pen 40, and a plurality of LEDs or LDs may be mounted.

  The power supply device 43 may be configured to include a battery, for example, or may be configured to be rechargeable.

  The control device 44 controls light emission of the light emitting element 42a. For example, a mechanism that emits light only when the light emitting element 42a contacts the light guide plate 10 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.

  In the touch pen 40 configured as described above, the light emitting element 42a that receives power from the power supply device 43 emits light of a predetermined wavelength. The light emitted from the light emitting element 42a enters the light scattering member 45 through the introducing portion 42b, and is irregularly reflected by the light diffusing material of the light scattering member 45 and the fine uneven shape. Then, the light is emitted as diffused light from the light emitting surface of the light scattering member 45.

  As described above, the touch pen 40 is provided with the light emitting unit 42 that emits light, and the light is diffused and emitted from the pen tip. Therefore, when the pen tip of the touch pen 40 contacts the light guide plate 10, part of the infrared light emitted from the pen tip is coupled to the light guide plate 10 and propagates through the light guide plate 10. Since the touch pen 40 diffuses and emits light from the pen tip, the light coupled to the light guide plate 10 is guided and propagated through the light guide plate 10 while diffusing and radiating.

  As shown in FIG. 5, the propagation lights 13 a and 14 a propagating through the light guide plate 10 enter the imaging units 20 and 30 through the through holes 11, respectively. In the imaging units 20 and 30, the angle formed with the imaging units 20 and 30 in the two-dimensional plane of the light guide plate 10 at the location where the touch pen 40 contacts is obtained from each image obtained from the imaging element 23. Thereby, based on the calculation principle of the two-dimensional coordinate described below, the position coordinate in the two-dimensional plane can be obtained with high accuracy.

(Calculation of 2D coordinate position)
Using the angle formed with the imaging units 20 and 30 in the two-dimensional plane of the light guide plate 10 at the location where the touch pen 40 comes into contact, the two-dimensional coordinate position at the location where the touch pen 40 comes into contact is obtained. The calculation method will be described below based on FIGS. 2 and 5 and FIGS. 8 (a) and 8 (b). FIG. 8A is a perspective view showing an imaging state of the imaging unit 20 in the coordinate input device 3A, and FIG. 8B is a plan view showing an image on the imaging element 23 of the imaging unit 20. FIG.

As shown in FIG. 5, first, when the pen tip of the touch pen 40 contacts the surface of the light guide plate 10 in the coordinate input device 3 </ b> A, part of the infrared light emitted from the touch pen 40 has a refractive index N. Incident in. 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. 5, the infrared light emitted from the touch pen 40 is diffused radially with respect to the two-dimensional plane of the light guide plate 10 around the pen tip and propagates in the light guide plate 10. A part of the propagation light 13a and 14a of the light flux is guided to the wall surface 11a of the conical surface through-hole 11, and the reflected light of the wall surface 11a is received by the imaging units 20 and 30. Specifically, the reflected light of the wall surface 11a of the through-hole 11 is collected by the lenses 21 and 31, and then passes through the visible light cut filters 22 and 32 and is finally received by the image sensors 23 and 33. The The visible light cut filters 22 and 32 transmit light in the wavelength band emitted from the touch pen 40 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, processing of the imaging units 20 and 30 will be described with reference to FIGS. 8A and 8B, only the imaging unit 20 will be described, but the same processing is performed in the imaging unit 30 as well.

  As shown in FIG. 2 and FIG. 8A, the light incident on the imaging unit 20 passes through the lens 21 and forms a linear image 25 on the imaging device 23. The position of the linear image 25 changes depending on the position of the touch pen 40, and the angles α and β formed by the propagation light 13a and 14a and one side of the light guide plate 10 are obtained by analyzing the acquired image of the imaging unit. Then, with the angles α and β, the position coordinates of the point where the pen tip serving as the light emission source is in contact with each other can be obtained using the triangulation method.

Specifically, in FIG. 8 (a), the case where the touch pen 40 is in the position of point P _1, as shown in FIG. 8 (b), the linear image 25 is formed. Also, the touch pen 40 when moved to the position of the point P _2, the image 27 of the line shape is formed.

  When the pen tip of the touch pen 40 in the state of irradiating light is not in contact with the light guide plate 10, nothing appears in the acquired image of the image sensor 23. On the other hand, when the pen tip of the touch pen 40 that is irradiating light from the light emitting unit 42 contacts the light guide plate 10 and infrared light is coupled to the light guide plate 10, the propagation light in a part of the light flux is Guided to the image sensor 23, a linear image is formed on the imaging surface of the image sensor 23, and a linear image 25 appears on the acquired image.

The position of the linear image 25 shown in FIG. 8B changes depending on the position of the contact point at the pen tip of the touch pen 40. When the position of the contact point of the pen tip is changed, the linear image 25 is changed. It changes like a linear image 27. The trajectories of the linear images 25 and 27 have a fan shape 26 indicated by a one-dot chain line. The inclination angle α ₁ ′ of the line segment connecting the fan-shaped center and the linear image 25 (with the center of the arc as the rotation center) is the above-described certain value of the light guide plate 10 and the line segment connecting the touch pen 40 and the image sensor 23 The angle is the same as the angle α ₁ formed by one side. Therefore, the inclination angle α ₁ ′ is obtained from the acquired image of the image sensor, and the angle α ₁ is obtained from the inclination angle α ₁ ′. Similarly, when the touch pen 40 moves to the position of the point P _2, a linear image 27 is formed, and the angle α ₂ is obtained by obtaining the inclination angle α ₂ ′ of the linear image 27.

  Similarly, for the image sensor 33, 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 touch pen 40 and the image sensor 33 and the certain side of the light guide plate 10 is obtained.

The distance between the image sensor 23 and the image sensor 33 is L, the angle of the bright spot obtained by reading the image from the image sensor 23 is α, and the angle of the bright spot obtained by reading the acquired image from the image sensor 23 is When β is defined, 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) ... Relational expression (2)
Satisfied. Solving this, the coordinates (X, Y) of the bright spot 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 and Y of the point where the pen tip contacts are obtained from the angles α and 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. By obtaining the angles α and β, the coordinates X and Y of the pen input position 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.

  In order to obtain the position coordinates of the touch pen 40 by the above method, the coordinate input system 1 is provided with a position coordinate detection unit (not shown). The position coordinate detection unit can be provided in the coordinate input device 3A.

  Further, based on the position coordinates of the touch pen 40 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 touch pen 40. Is 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.

(Measures in the detection limit area)
In the coordinate input device 3A of the present embodiment, as shown in FIG. 2, the contact position P of the touch pen 40 as the detection target is a region in the vicinity of the imaging units 20 and 30 as the light receiving means in the light guide plate 10. In this case, since the detection limit is exceeded, the detection accuracy is lowered. That is, in the calculation by the triangulation method, if the incident angle to at least one imaging unit 20 or the imaging unit 30 with respect to the line connecting the two imaging units 20 and 30 is too acute, the error is large even if the calculation is performed. Therefore, the detection accuracy is lowered.

  Therefore, in this embodiment, in order to avoid the occurrence of such a region where position detection is difficult, the light emitted from the light guide plate 10 is placed on the outer periphery of the light guide plate 10 as shown in FIG. A reflection plate 4 that reflects and re-enters the light guide plate 10 is provided. And the detection part 7 as a detection means is to the surface of the light-guide plate 10 in the touch pen 40 by the output of the imaging units 20 and 30 in the direct light from the touch pen 40 as a to-be-detected body and the reflected light by the reflecting plate 4. The coordinates of the contact position P are obtained.

  As a result, even when the viewing angle from the two image pickup units 20 and 30 to the touch pen 40 is small, the incident angle of the reflected light to the image pickup units 20 and 30 via the reflector 4 is large.

  Further, with this configuration, an increase in cost can be suppressed because an expensive detection unit is not increased.

  Therefore, it is possible to provide the coordinate input device 3A that can prevent a decrease in detection accuracy when the viewing angle from the imaging units 20 and 30 to the touch pen 40 is small while suppressing an increase in cost.

  Here, in the coordinate input device 3 </ b> A of the present embodiment, the plate-shaped light guide plate 10 has a rectangular shape, and the two imaging units 20 and 30 are provided in the vicinity of one side 10 c of the rectangular light guide plate 10. The reflecting plate 4 is either the outer periphery of one side 10c of the light guide plate 10 on the side where the two imaging units 20 and 30 are provided, or the outer periphery of the opposite side 10d opposite to the one side 10c, or Both are provided.

  Thereby, when the reflecting plate 4 is provided on the outer periphery of the one side 10c of the light guide plate 10 on the side where the two imaging units 20 and 30 are provided, the propagating light 13a · which is direct light from the touch pen 40 is provided. The viewing angle between the touch pen 40 and the imaging units 20 and 30 is obtained from the propagating light 13a and 13b and the propagating light 14a and 14b in two directions, for example, the propagating light 13b and 14b, which are reflected light from the reflecting plate 4. be able to. Therefore, even when the viewing angles of the propagation lights 13a and 14a that are direct light from the two imaging units 20 and 30 to the touch pen 40 are small, for example, the propagation light 13b that is one reflected light by the reflecting plate 4 of the side 10c. By adopting 14b, the viewing angle between the touch pen 40 and the imaging units 20 and 30 can be obtained with high accuracy. In this case, it is also possible to employ, for example, propagating light 13c and 14c, which is one reflected light by the reflecting plate 4 on the opposite side 10d.

  Further, as shown in FIG. 2, the reflectors 4, 4 have an outer periphery of one side 10 c of the light guide plate 10 on the side where the two imaging units 20, 30 are provided, and an outer periphery of the opposite side 10 d facing the one side 10 c , The propagation light 13a, 14a that is direct light from the touch pen 40, the propagation light 13b, 14b, and the propagation light 13c, 14c that are reflection light from the two reflectors 4, 4 are provided. The viewing angle between the touch pen 40 and the imaging units 20 and 30 can be obtained by the propagation lights 13a, 13b, and 13c in the three directions. Therefore, even when the viewing angles of the propagation lights 13a and 14a that are direct light from the two imaging units 20 and 30 to the touch pen 40 are small, the propagation lights 13b and 14b and the propagation lights 13c and 14c that are the two reflected lights. By adopting, the viewing angle between the touch pen 40 and the imaging units 20 and 30 can be obtained with higher accuracy.

  In the present embodiment, two imaging units 20 and 30 have been described. However, the present invention is not limited to this, and three or more imaging units may be provided.

  Further, in the coordinate input device 3A of the present embodiment, the light guide plate 10 receives the propagation light 13a, 13b, 13c and the propagation light 14a, 14b, 14c propagating through the light guide plate 10 from the direction of 360 degrees. Through holes 11 and 11 are provided as light extraction portions that are extracted below the lower surface of the light guide plate 10. The imaging units 20 and 30 receive the propagation lights 13a, 13b, and 13c and the propagation lights 14a, 14b, and 14c extracted through the through holes 11 and 11 below the lower surface of the light guide plate 10, respectively.

  Thereby, the through-hole 11 takes out the propagating light 13a / 13b / 13c and the propagating light 14a / 14b / 14c propagating through the inside of the light guide plate 10 from the direction of 360 degrees below the lower surface of the light guide plate 10. Therefore, regardless of the direction of propagation light 13b / 13c and propagation light 14b / 14c of the reflected light from the reflectors 4 and 4, the imaging units 20/30 receive the propagation light 13b / 13c and propagation light 14b / 14c. 14c can be received.

(Coordinate detection with multiple touch pens)
In the coordinate input device 3A and the coordinate input system 1 according to the present embodiment, even when a plurality of touch pens 40 are used, each touch pen 40 can be easily and reliably identified with a simple configuration. Yes. Below, the structure is demonstrated based on FIG.1 and FIG.2. FIG. 1 is a plan view showing the configuration of the coordinate input device 3A.

  As shown in FIG. 1, the case where two touch pens 40A and 40B are used as the plurality of touch pens 40 in the coordinate input device 3A of the present embodiment will be described. In the present invention, even when three or more touch pens 40 are used, the operation and effect thereof are the same as those when the three touch pens 40A and 40B are used.

  In the coordinate input device 3A of the present embodiment, the detected object can be used simultaneously with at least two touch pens 40A as the first detected objects and the touch pen 40B as the second detected objects. The touch pen 40 </ b> A and the touch pen 40 </ b> B are each a light emitting pen having a light emitting unit 42 that makes light incident on the light guide plate 10 by contacting the surface of the light guide plate 10. In addition, the imaging units 20 and 30 are incident on the light guide plate 10 from the light emitting units 42 and 42 of the touch pen 40A and the touch pen 40B, respectively, and propagate through the inside of the light guide plate 10 and the first propagation light 13a and the second propagation light. 14a, and the light emitted from the light guide plate 10 in the first propagation light 13a ′ and the second propagation light 14a ′ are received.

  In such a coordinate input device 3A, when two or more touch pens 40A and 40B as light emitting pens are used at the same time, and each touch pen 40A and touch pen 40B use light of the same wavelength region, FIG. 1, when two touch pens 40 </ b> A and 40 </ b> B are arranged in the line-of-sight direction of the imaging units 20 and 30, the light emitted from the touch pen 40 </ b> B located in the back as viewed from the imaging unit 20 Since it is interrupted by 40A, there arises a problem that the position cannot be detected by the triangulation method.

  In order to solve this problem, for example, the two touch pens 40A and 40B generate light of different wavelengths, and a pair of imaging units 20. If two sets of 30 are prepared, the number of parts of the apparatus increases and the cost increases.

  Here, in the present embodiment, first, even when two or more touch pens 40A and 40B that allow light to enter the light guide plate 10 are used simultaneously, the imaging units 20 and 30 are indispensable in the triangulation method. Only at least a pair of imaging units 20 and 30 are provided.

  In this situation, in order to identify the light emission from each touch pen 40A and touch pen 40B by the two imaging units 20 and 30, in this embodiment, as described above, the light emitted from the light guide plate 10 is reflected. Reflecting plates 4 and 4 for re-incident on the light guide plate 10 are provided. The reflecting plate 4 is provided on one or both of the outer periphery of one side 10c of the rectangular light guide plate 10 and the outer periphery of the opposite side 10d facing the one side 10c.

Further, the detection unit 7 serving as a detection unit includes propagation light 13a and 14a that are direct light from the touch pen 40A and the touch pen 40B, propagation light 13a 'and 14a', and propagation light 13b The position of the touch pen 40A and the touch pen 40B on the surface of the light guide plate 10 by the output of the imaging units 20 and 30 in the propagation light 13b and the propagation light 14b and 14c, and the propagation light 13b ′ and 13c ′ and the propagation light 14b ′ and 14c ′. The coordinates of P ₁ and P ₂ are obtained.

  That is, when two touch pens 40A and 40B are arranged in the line-of-sight direction of the imaging units 20 and 30, the propagating light 13a ′, which is direct light emitted from the touch pen 40B located behind the imaging unit 20, is Therefore, the position cannot be detected by the triangulation method. However, even in such a case, the propagation lights 13b and 13c and the propagation lights 14b and 14c, which are the reflected lights from the touch pen 40A and the touch pen 40B, and the propagation lights 13b ′ and 13c ′ and the propagation lights 14b ′ and 14c are reflected. 'Does not overlap.

As a result, even when two touch pens 40A and 40B are arranged in the line-of-sight direction of the imaging units 20 and 30, the contact positions P ₁ and P ₂ of the touch pen 40A and the touch pen 40B can be easily detected.

  Therefore, even when the object to be detected includes the touch pen 40A and the touch pen 40B as the light emitting pens, it is possible to provide the coordinate input device 3A that can simultaneously use the plurality of touch pens 40A and the touch pens 40B.

  As described above, the coordinate input device 3A of the present embodiment includes a plate-shaped light guide plate 10, at least two imaging units 20 and 30 that receive propagating light propagating through the light guide plate 10, and the surface of the light guide plate 10. The coordinates of the contact position of the touch pen 40, 40A, 40B on the surface of the light guide plate 10 based on the output of the imaging unit 20, 30 that detects the propagation light based on the touch pen 40, 40A, 40B. The detection part 7 which calculates | requires is provided. A reflection plate 4 that reflects light emitted from the light guide plate 10 and re-enters the light guide plate 10 is provided on the outer periphery of the light guide plate 10. The detection unit 7 detects the position of the touch pen 40, 40 A, 40 B on the surface of the light guide plate 10 by the output of the imaging units 20, 30 in the direct light from the touch pens 40, 40 A, 40 B and the reflected light from the reflector 4. Find the coordinates.

  As a result, even when the viewing angles from the two imaging units 20 and 30 to the touch pens 40, 40A, and 40B are small, the incident angle of the reflected light to the imaging units 20 and 30 via the reflector 4 is large.

  In addition, this configuration does not increase the number of expensive detection units, so that an increase in cost can be suppressed and the identification can be easily performed when a plurality of touch pens 40A and 40B are used simultaneously. it can.

  Therefore, it is possible to prevent a decrease in detection accuracy when the viewing angle from the imaging units 20 and 30 to the touch pen 40 is small while suppressing an increase in cost, and in addition, simultaneous use in a plurality of touch pens 40A and 40B is possible. The coordinate input device 3A can be provided.

  Further, in the coordinate input device 3A of the present embodiment, the plate-shaped light guide plate 10 has a rectangular shape, and at least two imaging units 20 and 30 are located in the vicinity of one side 10c of the rectangular light guide plate 10. The reflecting plate 4 is either the outer periphery of one side 10c of the light guide plate 10 on the side where at least two imaging units 20 and 30 are provided, or the outer periphery of the opposite side 10d facing the one side 10c. One or both are provided.

  Thereby, when the reflecting plate 4 is provided on either the one side 10c of the light guide plate 10 or the outer periphery of the opposing side 10d, direct light from the two imaging units 20 and 30 to the touch pen 40 is used. Even when the viewing angle is small, the viewing angle between the touch pen 40 and the imaging units 20 and 30 can be obtained with high accuracy by employing one reflector 4.

  Further, in the case where the reflection plate 4.4 is provided on both the periphery of the one side 10c and the periphery of the opposing side 10d, the direct light from the touch pen 40 and the two reflection plates 4 and 4 are provided. The viewing angle between the touch pen 40 and the imaging units 20 and 30 can be obtained from the propagating light in three directions with the reflected light from. Therefore, even when the viewing angle of the direct light from the two imaging units 20 and 30 to the touch pen 40 is small, the viewing angle between the touch pen 40 and the imaging units 20 and 30 can be reduced by adopting the two reflected lights. Further, it can be obtained with high accuracy.

  Further, in the coordinate input device 3A of the present embodiment, the light guide plate 10 is provided with a through hole 11 that takes out propagating light propagating through the light guide plate 10 from a direction of 360 degrees below the lower surface of the light guide plate 10. In addition, the imaging units 20 and 30 receive the propagation light extracted by the through holes 11 below the lower surface of the light guide plate 10.

  As a result, the imaging units 20 and 30 can receive the propagating light regardless of the direction in which the propagating light of the reflected light from the reflecting plate 4 propagates.

  In the coordinate input device 3A of the present embodiment, the detected object can be used simultaneously with at least two touch pens 40A and 40B. The touch pen 40A and the touch pen 40B are respectively placed on the surface of the light guide plate 10. It consists of a light emitting pen having a light emitting portion 42 for making light incident on the light guide plate 10 by contact. The imaging units 20 and 30 are incident on the light guide plate 10 from the light emitting units 42 and 42 of the touch pen 40A and the touch pen 40B, respectively, and propagate the first propagation light and the second propagation light propagating through the inside of the light guide plate 10. Light emitted from the optical member is received.

  As a result, even when two touch pens 40A and 40B are arranged in the line-of-sight direction of the imaging units 20 and 30, the contact positions of the touch pen 40A and the touch pen 40B can be easily detected by the reflected light from the reflection plate 4. can do.

  Therefore, even when the detected object includes the touch pen 40A and the touch pen 40B, it is possible to provide the coordinate input device 3A that can enable simultaneous use in the plurality of touch pens 40A and the touch pen 40B.

  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. For this reason, the coordinate input device 3 </ b> A can function as a touch panel that performs pen input while viewing the image of the liquid crystal display panel 2.

  Accordingly, it is possible to prevent a decrease in detection accuracy when the viewing angle from the imaging units 20 and 30 to the touch pen 40 is small while suppressing an increase in cost, and in addition, simultaneous use in the plurality of touch pens 40A and touch pens 40B is possible. The coordinate input system 1 provided with the coordinate input device 3A which can be made possible 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 and the coordinate input system 1 in the first embodiment, the detected object uses the touch pen 40 as the light-emitting pen or the two touch pens 40A and 40B. However, the coordinate input device 3B and the coordinate input system 1 according to the present embodiment are different in that a finger is used as a detection target and two fingers are used simultaneously.

  First, a configuration for detecting a finger as a detection target will be described.

(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. 9 is a perspective view showing the configuration of the coordinate input system.

  As shown in FIG. 9, the coordinate input system 1 according to the present embodiment includes a liquid crystal display panel 2 as an image display panel, and a coordinate input device 3 </ b> B 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, a finger 6 as a detection object is placed on a light guide plate 10 (to be described later) of a coordinate input device 3 </ b> B provided on the upper side of the liquid crystal display panel 2 while watching the screen displayed on the liquid crystal display panel 2. By making contact, 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 3B provided in the coordinate input system 1 will be described in detail below based on FIG.

  As shown in FIG. 9, the coordinate input device 3 </ b> B includes a light guide plate 10 as a rectangular transparent light guide member, imaging units 20 and 30 disposed on both ends of one side of the light guide plate 10, and a light guide plate. For example, a light source unit 5 as a light source provided around two sides, for example, and a detection unit 7 as detection means are provided.

  That is, the coordinate input device 3B of the present embodiment is different from the coordinate input device 3A described in the first embodiment in that the light source unit 5 is provided around the light guide plate 10.

  That is, the coordinate input device 3B of the present embodiment has a light source as a light source in which a plurality of LEDs (light emitting diodes) 5a that allow light to enter the light guide plate 10 are arranged around two sides of the light guide plate 10. Units 5 and 5 are provided along the two sides. These two sides are two 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 units 5 and 5 on the two sides of the light guide plate 10 face each other, and the imaging units 20 and 30 are provided within the illumination range of the illumination light from the light source unit 5. . In the present invention, the light source units 5 and 5 are not necessarily limited to the periphery of the two sides of the light guide plate 10, but are different from one side of the light guide plate 10 in which the imaging units 20 and 30 are provided at both ends, for example. It may be around three sides.

  A plurality of LEDs 5 a arranged in the light source unit 5 emit light such as infrared light. However, it is not necessarily limited to infrared light, and may be visible light or ultraviolet light. Further, the LED 5a is not necessarily used, and an LD (laser diode) or the like can be used.

  Next, as shown in FIG. 9, the coordinate input device 3B is provided with a detection unit 7 as detection means. The detection unit 7 detects a change 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 detected object such as a bar-shaped touch pen that does not emit light.

(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 3B having the above configuration will be described below with reference to FIGS. 10 and 11A and 11B. 10 is a cross-sectional view taken along line B-B in FIG. 9. FIG. 11A 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. 11B is a view in which the finger 6 is in contact with the light guide plate 10. It is a top view which shows the output image of the image pick-up element 23 at the time.

  First, in the coordinate input device 3B, as shown in FIGS. 9 and 10, light is incident on the light guide plate 10 from a plurality of LEDs 5 a... Provided along a periphery of at least one side of the light guide plate 10.

  The light incident on the light guide plate 10 is guided through the inside of the light guide plate 10 as propagating light, and is emitted through the through holes 11 to the image pickup devices 23 and 33 provided in at least two places. In FIG. 9, in addition to the imaging units 20 and 30 as the light receiving means, the imaging units 50 and 60 as the light receiving means are provided, but only the imaging units 20 and 30 may be provided. In other words, in the present invention, it is sufficient that at least two imaging units 20 and 30 as light receiving means are provided.

  With the light incident on the image sensor 23, the image sensor 23 obtains an output image of the fan-shaped bright portion 23a based on the shape of the wall surface 11a of the through hole 11 as shown in FIG. In FIG. 11A, 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 detection target is brought into contact with the surface of the light guide plate 10, the propagation light at the contact position P is disturbed. As a result, the intensity of light received by the image sensors 23 and 33 is reduced. Specifically, as shown in FIG. 11B, a linear dark part BL is generated in the bright part 23a. Therefore, by detecting the dark portion BL indicating the intensity reduction of the amount of received light in the imaging elements 23 and 33, the detection unit 7 can obtain the coordinates of the contact position of the finger 6 on the surface of the light guide plate 10.

  This detection principle will be described in detail.

As shown in FIG. 10, infrared light enters the light guide plate 10 having a refractive index N from one LED 5 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, a part of the light cannot satisfy the total reflection condition and is not confined in the light guide plate 10, and a 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. 11B, a linear dark portion BL appears in the output image that is the fan-shaped bright portion 23a shown in FIG. Therefore, based on the dark part BL, as described later, the detection part 7 can obtain the coordinates of the contact position of the finger 6 on the surface of the light guide plate 10. In FIG. 11B, only the output image of the image sensor 23 is shown, but the output image of the image sensor 33 is the same.

(Calculation method of 2D coordinate position)
Based on the dark portions BL 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 7 will be described with reference to FIGS. A description will be given below based on a) and (b).

  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. 10, infrared light enters the light guide plate 10 having a refractive index N from one LED 5 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. 9, the propagation lights 15a and 16a in a part of the light flux are also guided to the wall surfaces 11a and 11a of the conical surface through-holes 11 and 11, and the wall surfaces 11a and 11a. The reflected light is received by the imaging units 20 and 30. Specifically, as shown in FIG. 10, the reflected light of the wall surfaces 11a and 11a of the through holes 11 and 11 is collected by the lenses 21 and 31, and then passes through the visible light cut filters 22 and 32. Finally, the light is received by the image sensors 23 and 33. The visible light cut filters 22 and 32 transmit light in the wavelength band emitted by the LED 5a, 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 shown in FIG. 11A, the light incident on the imaging unit 20 forms a linear image on the imaging element 23 via the lens 21. Here, a plurality of LEDs 5a... Exist and enter the light guide plate 10 from a wide range of angles. For this reason, a plurality of linear images are gathered on the image sensor 23 to form a fan shape, and appear as an output image of the bright portion 23a in the image sensor 23 as shown in FIG.

  Next, in this state, detection of an output image on the imaging elements 23 and 33 when the finger 6 is in contact with, for example, the contact position P on the light guide plate 10 will be described.

In this case, as shown in FIG. 10, by contact with 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 propagation light 15a with the light amount reduced is guided to the wall surface 11a of the conical surface through hole 11, and the reflected light of the wall surface 11a is received by the imaging unit 20. Then, the light incident on the imaging unit 20 passes through the lens 21 and forms an image of the linear dark part BL in the fan-shaped bright part 23a in the imaging element 23 as shown in FIG.

  Similarly, for the image sensor 33, 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 33 and one side of the light guide plate 10 on the image pickup unit 20/30 side are formed. 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 (5) and relational expression (6)
Y = tan α · X (5)
Y = tan β · (L−X)... (6)
Satisfied. Solving this, the coordinates (X, Y) of the contact point are
X = tan β · L / (tan α + tan β) (7)
Y = (tan α · tan β) · L / (tan α + tan β) (8)
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 coordinates of the contact position P of the finger 6 obtained by the above method, the pixel at the position corresponding to the position coordinate of the liquid crystal display panel 2 is driven, and the user visually recognizes the touch position of the finger 6. It is possible to be able to 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 3B of the present embodiment includes the plate-shaped light guide plate 10, the light source unit 5 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 7 for obtaining the coordinates of the contact position P to the surface of the.

  Here, a conventional touch panel that detects the finger 6 is known to detect a light reception peak of scattered light due to the presence of the finger 6 in a state where the amount of light received by the light receiving means is maintained at zero. However, in this configuration, 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. Therefore, the signal quality of the contact detection in the detection object far away from the light receiving means is lowered, and there is a problem that it is difficult to apply to a large touch panel.

  Therefore, in the present embodiment, the imaging units 20 and 30 as the light receiving means are provided within the illumination light irradiation range, and the detection unit 7 includes the imaging units 20 and 30 based on light scattering by the finger 6. A change in output intensity is detected, and coordinates of the contact position of the finger 6 on the surface of the light guide plate 10 are obtained.

  That is, in this embodiment, the concept is changed from the conventional technique, and in the conventional technique, the received light peak of scattered light due to the presence of the detected object is detected, whereas in this embodiment, the imaging unit is detected. A change in output intensity in the imaging units 20 and 30 is detected based on light scattering due to the presence of the finger 6 in a state where a certain amount of received light is given to the 20 and 30 from the beginning.

  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 7.

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

(Measures in the detection limit area)
In the coordinate input device 3B of the present embodiment, as shown in FIG. 9, the contact position P of the finger 6 as the detected object is a region in the vicinity of the imaging units 20 and 30 as the light receiving means on the light guide plate 10. In this case, since the detection limit is exceeded, the detection accuracy is lowered. That is, in the calculation by the triangulation method, if the incident angle to at least one imaging unit 20 or the imaging unit 30 with respect to the line connecting the two imaging units 20 and 30 is too acute, the error is large even if the calculation is performed. Therefore, the detection accuracy is lowered.

  Therefore, in this embodiment, in order to avoid the occurrence of such a region where position detection is difficult, the light emitted from the light guide plate 10 is emitted to the outer periphery of the light guide plate 10 as shown in FIG. A reflection plate 4 that reflects and re-enters the light guide plate 10 is provided. And the detection part 7 as a detection means to the surface of the light-guide plate 10 in the finger 6 by the output of the imaging units 20 and 30 in the direct light from the finger 6 as a to-be-detected body and the reflected light by the reflecting plate 4 The coordinates of the contact position P are obtained.

  As a result, even when the viewing angle from the two imaging units 20 and 30 to the finger 6 is small, the incident angle of the reflected light to the imaging units 20 and 30 via the reflector 4 is large.

  Further, with this configuration, an increase in cost can be suppressed because an expensive detection unit is not increased.

  Therefore, it is possible to provide the coordinate input device 3B that can prevent a decrease in detection accuracy when the viewing angle from the imaging units 20 and 30 to the finger 6 is small while suppressing an increase in cost.

  Here, in the coordinate input device 3B of the present embodiment, the plate-shaped light guide plate 10 is square, and the two imaging units 20 and 30 are provided in the vicinity of one side 10c of the square light guide plate 10. The reflecting plate 4 is either the outer periphery of one side 10c of the light guide plate 10 on the side where the two imaging units 20 and 30 are provided, or the outer periphery of the opposite side 10d opposite to the one side 10c, or Both are provided.

  Thereby, when the reflection plate 4 is provided on the outer periphery of the one side 10c of the light guide plate 10 on the side where the two imaging units 20 and 30 are provided, the propagation light 15a that is direct scattered light from the finger 6 is provided. The viewing angle between the finger 6 and the imaging units 20 and 30 is determined by the propagation light 15a and 15b and the propagation light 16a and 16b in two directions, for example, propagation light 15b and 16b, which are reflected light from the reflecting plate 4 and 16a. Can be sought. Therefore, even when the viewing angles of the propagation lights 15a and 16a that are direct light from the two imaging units 20 and 30 to the finger 6 are small, for example, the propagation light 15b that is one reflected light by the reflection plate 4 of the side 10c. By adopting 16b, the viewing angle between the touch pen 40 and the imaging units 20 and 30 can be obtained with high accuracy. In this case, it is also possible to employ, for example, propagating light 15c and 16c, which is one reflected light by the reflecting plate 4 on the opposite side 10d.

  Further, as shown in FIG. 9, the reflectors 4 and 4 are arranged so that the outer periphery of the side 10 c on the side of the light guide plate 10 where the two imaging units 20 and 30 are provided and the outer periphery of the opposite side 10 d facing the side 10 c. , The propagation lights 15a and 16a that are direct light from the finger 6, and the propagation lights 15b and 16b and the propagation lights 15c and 16c that are reflection lights from the two reflecting plates 4 and 4 are provided. The viewing angle between the finger 6 and the imaging units 20 and 30 can be obtained by the propagation lights 15a, 15b, and 15c in the three directions. Therefore, even when the viewing angles of the propagation lights 15a and 16a that are direct light from the two imaging units 20 and 30 to the finger 6 are small, the propagation lights 15b and 16b and the propagation lights 15c and 16c that are the two reflected lights. By adopting, the viewing angle between the finger 6 and the imaging units 20 and 30 can be obtained more accurately.

  Further, in the coordinate input device 3B of the present embodiment, the light guide plate 10 receives the propagating light 15a, 15b, 15c and the propagating light 16a, 16b, 16c propagating through the light guide plate 10 from a direction of 360 degrees. Through holes 11 and 11 are provided as light extraction portions that are extracted below the lower surface of the light guide plate 10. The imaging units 20 and 30 receive the propagation lights 15a, 15b, and 15c and the propagation lights 16a, 16b, and 16c extracted by the through holes 11 and 11 below the lower surface of the light guide plate 10, respectively.

  Thereby, the through-hole 11 takes out the propagating light 15a, 15b, 15c and the propagating light 16a, 16b, 16c propagating through the inside of the light guide plate 10 from below the lower surface of the light guide plate 10 from 360 degrees. For this reason, the imaging units 20 and 30 receive the propagation light 15b and 15c and the propagation light 16b and the propagation light 15b and the propagation light 16b and the propagation light 16b and 16c from any direction. 16c can be received.

(Simultaneous use of two fingers)
In the coordinate input device 3B and the coordinate input system 1 of the present embodiment, even when a plurality of fingers 6 are used, each finger 6 can be easily and reliably identified with a simple configuration. Yes.

  In addition, since the structure in the case of using the several finger | toe 6 is the same as the content demonstrated in the said Embodiment 1 (simultaneous use of two touch pens), the description is abbreviate | omitted.

  As described above, the coordinate input device 3B of the present embodiment includes the light guide plate 10 as a plate-shaped light guide member, and at least two imaging units 20 and 30 that receive the propagation light propagating through the light guide plate 10. Based on the output of the imaging units 20 and 30 that detect the propagation light based on the contact when the finger 6 as the detection object contacts the surface of the light guide plate 10, the finger 6 contacts the surface of the light guide plate 10. And a detection unit 7 as detection means for obtaining the coordinates of the position P.

  The outer periphery of the light guide plate 10 is provided with a reflection plate 4 that reflects light emitted from the light guide plate 10 and re-enters the light guide plate 10. The coordinates of the contact position P of the finger 6 with respect to the surface of the light guide plate 10 are obtained by the output of the imaging units 20 and 30 in the light and the reflected light from the reflector 4.

  As a result, even when the viewing angle from the two imaging units 20 and 30 to the finger 6 is small, the incident angle of the reflected light to the imaging units 20 and 30 via the reflector 4 is large.

  In addition, this configuration does not increase the number of expensive detection units, so that an increase in cost can be suppressed and the identification can be easily performed when a plurality of fingers 6 are used at the same time.

  Therefore, it is possible to prevent a decrease in detection accuracy when the viewing angle from the imaging units 20 and 30 to the finger 6 is small while suppressing an increase in cost, and in addition, simultaneous use with a plurality of fingers 6 can be enabled. A coordinate input device 3B can be provided.

  Further, in the coordinate input device 3B of the present embodiment, the plate-shaped light guide plate 10 has a square shape, and at least two imaging units 20 and 30 are provided in the vicinity of one side of the square light guide plate 10. The reflecting plate 4 is either the outer periphery of one side 10c of the light guide plate 10 on the side where at least two imaging units 20 and 30 are provided or the outer periphery of the opposite side 10d facing the one side 10c. Or both.

  Therefore, even when the viewing angle of the direct light from the two imaging units 20 and 30 to the finger 6 is small, by adopting the reflected light, the viewing angle between the finger 6 and the imaging units 20 and 30 can be accurately adjusted. Can be sought.

  Further, in the coordinate input device 3B of the present embodiment, the light guide plate 10 serves as a light extraction unit that extracts propagating light propagating through the light guide plate 10 from a direction of 360 degrees below the lower surface of the light guide plate 10. The through-hole 11 is provided, and the imaging units 20 and 30 receive propagating light extracted by the through-hole 11 below the lower surface of the light guide plate 10.

  As a result, the imaging units 20 and 30 can receive the propagating light regardless of the direction in which the propagating light of the reflected light from the reflecting plate 4 propagates.

  Further, in the coordinate input device 3B of the present embodiment, the finger 6 can be used simultaneously with at least two fingers 6 as the first detected body and fingers 6 as the second detected body, A light source unit 5 is provided as a light source for making illumination light incident from the end of the light guide plate 10, and the fingers 6 and 6 scatter the illumination light propagating through the light guide plate 10 by contacting the surface of the light guide plate 10. The imaging units 20 and 30 are configured such that the illumination light propagating in the light guide plate 10, the first propagation light that is the scattered light by the finger 6, and the second propagation that is the scattered light by the other finger 6. In addition to receiving light, the detection unit 7 detects a change in output intensity of the imaging units 20 and 30 based on scattering of illumination light due to contact of the fingers 6 and 6 with the light guide plate 10, and detects each finger 6 and 6. 6 to obtain the coordinates of the position of contact with the surface of the light guide plate 10 .

  As a result, even when the two fingers 6 and 6 are arranged in the line-of-sight direction of the imaging units 20 and 30, the contact positions P and P of the fingers 6 and 6 can be easily detected.

  Therefore, even when the detected object is a detected object that does not use the light-emitting pen such as the finger 6, the coordinate input device 3 </ b> B that can simultaneously use the plurality of fingers 6 and 6 can be provided.

  A coordinate input system 1 according to the present embodiment is a coordinate input system 1 including the coordinate input device 3B according to the present embodiment, and includes a liquid crystal display panel 2. For this reason, the coordinate input device 3 </ b> B can function as a touch panel for performing finger input while viewing the image of the liquid crystal display panel 2.

  Accordingly, it is possible to prevent a decrease in detection accuracy when the viewing angle from the imaging units 20 and 30 to the finger 6 is small while suppressing an increase in cost, and in addition, simultaneous use with a plurality of fingers 6 and 6 is possible. It is possible to provide a coordinate input system 1 including a coordinate input device 3B.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and the technical means disclosed in the other embodiments are appropriately combined. The obtained embodiment is also included in the technical scope of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be used for an optical coordinate input device and a coordinate input system that simultaneously use a plurality of detection objects such as fingers or a bar-shaped operation member pen such as a touch pen or a stylus pen.

1 Coordinate input system 2 Liquid crystal display panel (image display panel)
3A Coordinate input device 3B Coordinate input device 4 Reflector 5 Light source unit (light source)
5a LED
6 fingers (detected body)
7 Detection part (detection means)
10 Light guide plate (light guide member)
10c One side 10d Opposing side 11 Through hole (light extraction part)
11a Wall surfaces 12a and 13a Propagating light (direct light)
12b / 12c Propagating light [reflected light]
13b / 13c Propagating light [reflected light]
15a, 16a Propagating light (direct light)
15b / 15c Propagating light [reflected light]
16b, 16c Propagating light [reflected light]
20 Imaging unit (light receiving means)
21 Lens 22 Visible Light Cut Filter 23 Image Sensor (Light Receiving Unit)
23a Bright part 25 Image 27 Image 30 Imaging unit (light receiving means)
31 Lens 32 Visible Light Cut Filter 33 Image Sensor (Light Receiving Unit)
40 Touch pen (light emitting pen, object to be detected)
40A touch pen (light emitting pen, object to be detected)
40B Touch pen (light emitting pen, object to be detected)
42 Light Emitting Unit 45 Light Scattering Member 50 Imaging Unit (Light Receiving Unit)
60 Imaging unit (light receiving means)
BL Dark part L interval

Claims (6)

A plate-shaped light guide member, at least two light receiving means for receiving propagation light propagating in the light guide member, and propagation light based on the contact when the object to be detected contacts the surface of the light guide member A coordinate input device comprising detection means for obtaining coordinates of a position of contact of the light guide member with the surface of the light guide member based on the detected output of the light receiving means;
On the outer periphery of the light guide member, a reflection plate that reflects light emitted from the light guide member and re-enters the light guide member is provided.
The detection means obtains the coordinates of the contact position of the light guide member on the detected body with the output of the light receiving means in the direct light from the detected body and the reflected light from the reflector. Input device. The plate-shaped light guide member has a square shape,
The at least two light receiving means are provided in the vicinity of one side of the rectangular light guide member,
The reflector is provided on one or both of the outer periphery of one side of the light guide member on the side where the at least two light receiving means are provided, or the outer periphery of the opposite side opposite to the one side. The coordinate input device according to claim 1, wherein: The light guide member is provided with a light extraction portion that extracts propagation light propagating through the light guide member from a direction of 360 degrees below the lower surface of the light guide member.
The coordinate input device according to claim 1, wherein the light receiving unit receives the propagating light extracted by the light extraction unit below the lower surface of the light guide member. The detected object can be used simultaneously with at least two first detected objects and a second detected object,
The first detected body and the second detected body are each composed of a light emitting pen having a light emitting portion that makes light incident on the light guide member by contacting the surface of the light guide member, and
In the first propagation light and the second propagation light, the light receiving means is incident on the light guide member from the light emitting portions of the first detection body and the second detection body, respectively, and propagates in the light guide member. The coordinate input device according to claim 1, wherein the light emitted from the light guide member is received. The detected object can be used simultaneously with at least two first detected objects and a second detected object,
A light source for allowing illumination light to enter from an end of the light guide member;
The first detected body and the second detected body are adapted to scatter the illumination light propagating through the light guide member by contacting the surface of the light guide member,
The light receiving means includes illumination light propagating in the light guide member, first propagated light that is scattered light by the first detected object, and second propagated light that is scattered light by the second detected object. While receiving light,
The detection means detects a change in output intensity of the light receiving means based on the scattering of the illumination light due to contact of the first detected body and the second detected body with the light guide member, and the first detected body and The coordinate input device according to claim 1, 2, or 3, wherein coordinates of a contact position on the surface of the light guide member in the second detected body are obtained. A coordinate input system comprising the coordinate input device according to claim 1,
A coordinate input system comprising an image display panel.

Images