JP2013156861A - Coordinate input device, coordinate correcting method of coordinate input device and coordinate input system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical coordinate input device using a light guide member capable of preventing degradation of the coordinate detection accuracy by automatically calibrating and correcting detected coordinates due to an elongation/compaction or a displacement of the light guide member, a coordinates correcting method of the coordinate input device and a coordinate input system.SOLUTION: The optical coordinate input device includes: a calibrating light source 4 provided to a predetermined position for inputting a beam of light from the surface of a light guide plate 10 to calibrate the touch position with a touch pen 40 on the surface of the light guide plate 10 due to an elongation/compaction and a displacement of the light guide plate 10; a coordinate calibrating correction section 50 that calculates a displacement amount by comparing the coordinates of an incident position of the light from the calibrating light source 4 which is detected by turning on the calibrating light source 4 to the known precise coordinates of the calibrating light source 4; and a coordinate calibrating correction section 50 that corrects the detected coordinates on the basis of the displacement amount when the coordinates of the touch position are detected by bringing the touch pen 40 into contact with the surface of the light guide plate 10.

Description

  The present invention includes a light guide member, and detects the propagating light propagating through the light guide member by bringing the operation tool into contact with the surface of the light guide member, and detects the surface of the light guide member in the operation tool. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coordinate input device that detects the coordinates of a contact position to a coordinate system, a coordinate correction method for the coordinate input device, and a coordinate input system. Related to calibration and correction.

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

  In the coordinate input system, the coordinate input device or the position detection device obtains the coordinates of the approached or touched position of the pen by bringing the pen close to or in contact with the coordinate input region of the coordinate input device. The obtained coordinates are for displaying an object such as a point image or a straight line image on a display screen such as a liquid crystal display separate from the coordinate input device or a liquid crystal panel integrally laminated on the coordinate input device. Used for etc.

  For example, as shown in FIGS. 12A and 12B, the position detection device 100 disclosed in Patent Document 1 includes a light guide plate 101 that is a light guide member made of a translucent material, and side surfaces of the light guide plate 101. Light sources 102 such as semiconductor infrared lasers that make light incident in a plurality of rows in the X direction and the Y direction, a lighting control unit 103 that controls the lighting by sequentially scanning the light sources 102, and the light guide plate 101 And a touch pen 110 that detects the contact position when touched. In addition, as shown in FIG. 12C, the touch pen 110 is brought into contact with the light guide plate 101 to introduce light that guides light inside the light guide plate 101, and the introduction portion 111 introduces the touch pen 110. Based on the detection unit 112 that detects light and outputs a detection signal, and the detection signal output from the detection unit 112 and the scanning position by the lighting control unit 103, the coordinate position where the touch pen 110 contacts the light guide plate 101 is calculated. A coordinate calculation unit 113, an identification signal generation unit 114, and a transmission unit 115.

  In the position detection apparatus 100, the light sources 102 are sequentially controlled to be lit from the left to the right of the light guide plate 101 and from the bottom to the top. At this time, when the touch pen 110 is pressed against a certain position of the light guide plate 101, the introduction part 111 of the touch pen 110 is brought into close contact with the light guide plate 101, whereby the total reflection condition of the light totally reflected on the surface of the light guide plate 101 is satisfied. It collapses and is introduced into the introduction part 111. The light introduced into the introduction unit 111 is detected by the detection unit 112 and outputs a detection signal. Based on this output, the coordinate calculation unit 113 calculates the coordinates of the contact point. Specifically, the two-dimensional coordinate position on the light guide plate 101 can be calculated by calculating from which light source 102 the detected light beam is detected from the detection signal output from the detection unit 112. . The calculated two-dimensional coordinate position is generated by the identification signal generation unit 114 so that a different signal frequency is generated for each of the touch pens 110 and 110, and is transmitted from the transmission unit 115 to a receiving device (not shown) at the signal frequency. It has become.

JP 2008-158616 A (released July 10, 2008)

  However, since the position detection apparatus 100 disclosed in the above-described conventional Patent Document 1 uses the light guide plate 101, when the light guide plate 101 expands or contracts, the coordinate position with which the touch pen 110 contacts is determined. There is a problem that the accurate coordinate position is shifted and the coordinate detection accuracy is lowered.

  In addition, if an infrared light shielding type coordinate input device is employed, if an object such as a finger other than the touch pen touches the detection area during calibration, the infrared light in the vicinity thereof is blocked. Therefore, accurate calibration cannot be performed, and as a result, the coordinate detection accuracy may also decrease.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to automatically detect detected coordinates accompanying expansion / contraction or positional deviation of a light guide member in an optical coordinate input device using the light guide member. An object of the present invention is to provide a coordinate input device, a coordinate correction method for a coordinate input device, and a coordinate input system that can be calibrated and corrected to prevent deterioration of coordinate detection accuracy.

  In order to solve the above-described problem, the coordinate input device of the present invention includes a light guide member, and a light receiving unit transmits propagating light propagating through the light guide member by bringing an operation tool into contact with the surface of the light guide member. A coordinate input device that detects and detects the coordinates of the position of contact with the surface of the light guide member in the operation tool, to the surface of the light guide member in the operation tool accompanying expansion and contraction of the light guide member In order to calibrate the contact position, a calibration light source that is provided at a predetermined position and makes light incident from the surface of the light guide member, and an incident position of light in the calibration light source detected by turning on the calibration light source And the coordinate calibration means for comparing the known accurate coordinates of the light source for calibration to obtain the amount of positional deviation, and the coordinates of the contact position were detected by bringing the operating tool into contact with the surface of the light guide member. Sometimes the above displacement amount And coordinate correcting means for correcting the detected coordinates based is characterized by being provided.

  According to the above invention, the coordinate input device includes the light guide member, and detects the propagating light propagating through the light guide member at the light receiving unit by bringing the operation tool into contact with or close to the surface of the light guide member. The coordinates of the position of contact with the surface of the light guide member in the operation tool are detected.

  In an optical coordinate input device provided with such a light guide member, the light guide member may be stretched or displaced in use. In this case, the positional relationship between the operation tool and the light receiving unit is shifted, and the coordinate detection accuracy is lowered.

  In order to prevent a decrease in the coordinate detection accuracy, for example, when the operation tool is a touch pen having a light emitting unit, the position of the operation tool and the light receiving unit is brought into contact with a predetermined position by touching the touch pen. It is possible to calibrate the relationship. However, such a calibration method requires the user to bring the touch pen into contact with a predetermined position, which is cumbersome and burdensome for the user.

  Therefore, in the present invention, in order to calibrate the contact position of the operation tool with the surface of the light guide member accompanying the expansion and contraction of the light guide member, light is emitted from the surface of the light guide member. The amount of positional deviation is obtained by comparing the calibration light source incident on the calibration light source, the coordinates of the light incident position in the calibration light source detected by turning on the calibration light source, and the known accurate coordinates in the calibration light source. And a coordinate correction means for correcting the detected coordinates based on the amount of displacement when the operation tool is brought into contact with the surface of the light guide member and the coordinates of the contact position are detected. ing.

  As a result, at the time of calibration, the coordinates serving as a reference are not automatically detected by the user and are automatically detected from a fixed location. For this reason, a user's burden does not generate | occur | produce.

  In addition, if an infrared light shielding type coordinate input device is employed, if an object such as a finger other than the touch pen touches the detection area during calibration, the infrared light in the vicinity thereof is blocked. Therefore, there is a risk of malfunction. However, in the present invention, a coordinate input device using a light guide member is employed, and light from a calibration light source is incident on the light guide member. For this reason, since light does not pass through the air, calibration is not inaccurate due to external influences such as a finger during calibration.

  Therefore, in an optical coordinate input device that uses a light guide member, a coordinate input device that can automatically calibrate and correct detected coordinates accompanying the expansion or contraction of the light guide member to prevent a decrease in coordinate detection accuracy. Can be provided.

  In the coordinate input device according to the aspect of the invention, the operation tool includes a light emitting unit that causes light to enter the light guide member by contacting the surface of the light guide member. It can be assumed that there is provided an optical path changing unit that linearly emits the propagating light that is incident from the tool and guides the inside of the light guide member to the light receiving units provided in at least two places.

  Thereby, light is emitted from a light emitting unit in, for example, a touch pen as an operation tool. The light is incident on the light guide member, and the propagating light is emitted to the outside of the light guide member via the optical path changing portions provided at least at two locations, and linearly transmitted to the light receiving portions provided at at least two locations. Is emitted.

  For this reason, in each light-receiving part, since the interval between each light-receiving part and two angles in the triangle connecting each light-receiving part and the contact position of the touch pen to the light-guiding member can be known, the light guide member of the touch pen is obtained by triangulation. The coordinates of the contact position can be obtained.

  Therefore, it is possible to provide a coordinate input device that uses a triangulation method to obtain coordinates of a contact position of the touch pen with respect to the light guide member by using the light guide member and causing light to enter the light guide member from the touch pen. .

  In order to solve the above problems, a coordinate correction method for a coordinate input device according to the present invention includes a light guide member, and propagates light propagating through the light guide member by bringing an operation tool into contact with the surface of the light guide member. A coordinate correction method for a coordinate input device that is detected by a light receiving unit and detects coordinates of a position of contact with the surface of the light guide member in the operation tool, wherein the light guide is turned on in a power-on state of the coordinate input device. By illuminating a calibration light source provided at a known accurate coordinate position on the member, the light from the calibration light source is incident on the light guide member, and the propagation light propagating through the light guide member is detected by the light receiving unit. A calibration light source coordinate detection step for detecting the coordinates of the light incident position in the calibration light source, the coordinates of the light incidence position in the calibration light source obtained in the calibration light source coordinate detection step, and the calibration Known in light sources A positional deviation amount calculating step for obtaining a positional deviation amount by comparing with accurate coordinates, and a propagating light propagating through the light guide member by contact with the operation tool is detected by the light receiving unit, and guided in the operation tool. A coordinate correction step of correcting the detected coordinates based on the positional deviation amount when the coordinates of the position of contact with the surface of the optical member are detected.

  According to the above invention, the coordinate input device includes the light guide member, and detects the propagating light propagating through the light guide member by bringing the operation tool into contact with the surface of the light guide member. The coordinate of the contact position on the surface of the light guide member in the operation tool is detected.

  In an optical coordinate input device provided with such a light guide member, the light guide member may be stretched or displaced in use. In this case, the positional relationship between the operation tool and the light receiving unit is shifted, and the coordinate detection accuracy is lowered.

  Therefore, when the operation tool is a touch pen having a light emitting unit, for example, it is conceivable to calibrate the positional relationship between the operation tool and the light receiving unit by bringing the touch pen into contact with a predetermined position. However, such a calibration method requires the user to bring the touch pen into contact with a predetermined position, which is cumbersome and burdensome for the user.

  In order to solve this problem, in the present invention, when the coordinates of the coordinate input device are calibrated, in the calibration light source coordinate detection step, when the power of the coordinate input device is turned on, the known accurate coordinates of the light guide member The calibration light source is turned on so that the light from the calibration light source is incident on the light guide member, and the propagating light propagating through the light guide member is detected by the light receiving unit. The coordinates of the light incident position at are detected.

  Next, in the positional deviation amount calculation step, the positional deviation is made by comparing the coordinates of the incident position of the light in the calibration light source obtained in the calibration light source coordinate detection step with the known accurate coordinates in the calibration light source. Find the amount.

  Thereafter, in the coordinate correction process, the light that propagates through the light guide member is detected by the light receiving unit by contacting the operation tool, and the coordinates of the contact position of the operation tool on the surface of the light guide member are detected. When detected, the detected coordinates are corrected based on the amount of positional deviation.

  As a result, at the time of calibration, the coordinates serving as a reference are not automatically detected by the user and are automatically detected from a fixed location. For this reason, a user's burden does not generate | occur | produce.

  In addition, if an infrared light shielding type coordinate input device is employed, if an object such as a finger other than the touch pen touches the detection area during calibration, the infrared light in the vicinity thereof is blocked. Therefore, there is a risk of malfunction. However, in the present invention, a coordinate input device using a light guide member is employed, and light from a calibration light source is incident on the light guide member. For this reason, since light does not pass through the air, calibration is not inaccurate due to external influences such as a finger during calibration.

  Therefore, in an optical coordinate input device that uses a light guide member, a coordinate input device that can automatically calibrate and correct detected coordinates accompanying expansion or contraction of the light guide member to prevent a decrease in coordinate detection accuracy. A coordinate correction method can be provided.

  In the coordinate correction method of the coordinate input device of the present invention, it is preferable that the calibration light source coordinate detection step and the positional deviation amount calculation step are performed when the power of the coordinate input device is turned on and thereafter every predetermined time.

  Thus, when the power of the coordinate input device is turned on, the light guide member is automatically calibrated automatically in the calibration light source coordinate detection step and the positional deviation amount calculation step. As a result, when the coordinate input device is dropped when the power is turned off in the coordinate input device and the light guide member is misaligned, even if the operator does not know the fact, the detected coordinates are It is possible to provide a coordinate correction method for a coordinate input device that can automatically calibrate and correct to prevent a decrease in coordinate detection accuracy.

  In the present invention, the calibration light source coordinate detection step and the positional deviation amount calculation step are performed at regular intervals while the power of the coordinate input device is turned on.

  For this reason, even if the light guide member expands due to thermal expansion due to the long-term use of the coordinate input device, the coordinate input can automatically calibrate and correct the detected coordinates to prevent a decrease in coordinate detection accuracy. An apparatus coordinate correction method can be provided.

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

  According to said invention, a coordinate input device can be functioned as a touchscreen which inputs with a touch pen or a finger, seeing the image of an image display panel. Therefore, in an optical coordinate input device that uses a light guide member, a coordinate input device that can automatically calibrate and correct detected coordinates accompanying the expansion or contraction of the light guide member to prevent a decrease in coordinate detection accuracy. A coordinate input system can be provided.

  As described above, the coordinate input device of the present invention is provided at a predetermined position to calibrate the contact position of the operation tool with the surface of the light guide member in accordance with the expansion and contraction of the light guide member. Compare the calibration light source that makes light incident from the surface of the member, the coordinates of the light incident position in the calibration light source detected by turning on the calibration light source, and the known accurate coordinates in the calibration light source Coordinate correction means for obtaining a displacement amount, and coordinate correction for correcting the detected coordinates based on the displacement amount when the operation tool is brought into contact with the surface of the light guide member and the coordinates of the contact position are detected. Means.

  As described above, the coordinate correction method of the coordinate input device according to the present invention is to turn on the calibration light source provided at the known accurate coordinate position in the light guide member in the power-on state of the coordinate input device. The calibration light source detects the coordinates of the incident position of the light in the calibration light source by causing the light from the calibration light source to enter the light guide member and detecting the propagation light propagating through the light guide member by the light receiving unit. Misalignment to determine the amount of misalignment by comparing the coordinates of the incident position of light in the calibration light source obtained in the coordinate detection step and the calibration light source coordinate detection step with known accurate coordinates in the calibration light source When the light receiving unit detects the propagation light propagating through the light guide member by bringing the operation tool into contact with the amount calculation step, and detects the coordinates of the contact position on the surface of the light guide member in the operation tool , The amount of displacement A method and a coordinate correction step of correcting the detected coordinates based.

  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, in an optical coordinate input device that uses a light guide member, a coordinate input device that can automatically calibrate and correct detected coordinates accompanying the expansion or contraction of the light guide member to prevent a decrease in coordinate detection accuracy. The coordinate correction method of the coordinate input device and the coordinate input system are provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view illustrating an overall configuration of a coordinate input system including a coordinate input device according to an embodiment of a coordinate input device and a coordinate input system according to the present invention. 1 shows the overall configuration of the coordinate input system, and is a cross-sectional view taken along line AA in FIG. 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. It is sectional drawing which shows the structure of the light-scattering member provided in the front-end | tip of the said touch pen. (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. (A) is a top view which shows arrangement | positioning of the light source for calibration in the said coordinate input device, (b) is sectional drawing which shows arrangement | positioning of the light source for calibration in the said coordinate input device. It is a main flowchart which shows the coordinate calibration method in the coordinate input device using the said calibration light source, and the coordinate correction method based on the calibration. It is a subroutine flowchart which shows the flow of the coordinate calibration process in the coordinate input device using the said light source for a calibration. It is a subroutine flowchart which shows the flow of the coordinate correction process in the coordinate input device using the said calibration light source. It is a perspective view which shows the modification in the said coordinate input device, Comprising: The whole structure of a coordinate input device. FIG. 11 is an overall configuration of a coordinate input system including the coordinate input device according to the modified example, and is a cross-sectional view taken along line BB in FIG. 10. (A) is a top view which shows the structure of the position detection apparatus as a conventional coordinate input device, (b) is sectional drawing which shows the structure of the said position detection apparatus, (c) is the housing | casing of the upper surface in a touch pen It is a top view which removes and shows.

  One embodiment of the present invention will be described below with reference to FIGS.

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

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

  The liquid crystal display panel 2 has a liquid crystal layer sandwiched between a pair of substrates (not shown), and each substrate is provided with at least various electrodes for changing the orientation of liquid crystal molecules of the liquid crystal layer by applying a voltage. . Then, by changing the orientation of the liquid crystal molecules by applying a voltage, the amount of light transmitted through the liquid crystal layer of each pixel is adjusted to perform a desired display. As the configuration of the liquid crystal display panel 2, a conventionally known liquid crystal display panel can be used.

  In the coordinate input system 1, for example, a touch pen 40 as an operation tool is placed on a light guide plate 10 (to be described later) of the coordinate input device 3 provided on the upper side of the liquid crystal display panel 2 while viewing the screen displayed on the liquid crystal display panel 2. By 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 3 provided in the coordinate input system 1 will be described in detail below based on FIG. 1 and FIG. FIG. 2 is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 1, the coordinate input device 3 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. 10 and a touch pen 40 as an operation tool to be contacted.

  The light guide plate 10 is made of a single flat plate made of a translucent material, and is disposed so as to overlap the display surface side of the liquid crystal display panel 2. The size of the light guide plate 10 is a quadrangle having substantially the same size as the liquid crystal display panel. Specifically, as shown in FIG. 1, one side where the imaging units 20 and 30 are disposed is configured to be larger than the liquid crystal display panel 2. Accordingly, at least a part of the imaging units 20 and 30 can be disposed on the back side of the light guide plate 10. As a result, an increase in the size of the coordinate input device 3 in the direction of spreading along the contact surface to the light guide plate 10 in the touch pen 40 is suppressed, contributing to the realization of a compact size of the coordinate input device 3.

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

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

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

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

  The imaging unit 20 includes a lens 21, a visible light cut filter 22, and an imaging element 23 as a light receiving unit. Similarly, the imaging unit 30 includes a lens 31, a visible light cut filter 32, and an imaging element 33 as a light receiving unit. The light receiving surfaces of the image sensors 23 and 33 are arranged so as to be parallel to the surface of the light guide plate 10.

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

  In the present embodiment, the notch 11 is configured in a conical surface shape, but the present invention is not limited to this and may be configured in a polygonal surface shape.

(Configuration of touch pen)
Next, the configuration of the touch pen according to the present embodiment will be described with reference to FIGS. FIG. 3 is a plan view showing the configuration of the touch pen 40 of the present embodiment. In FIG. 3, for convenience of explanation, a part of the housing is removed to expose the internal structure. FIG. 4 is a cross-sectional view showing the configuration of the light scattering member provided at the tip of the touch pen.

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

  As shown in FIG. 3, 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 42a that emits light and the light emitted from the light emitting element 42a into a housing 41 that forms an 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 an 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 3, 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, as shown in FIG. 4, 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 exit surface of the light scattering member 45 has a curved surface as shown in FIG. 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, when the light scattering member 45 is used in contact with the light guide plate 10 of the coordinate input device 3, there is a possibility that light that can ensure a sufficient contact area is not sufficiently introduced into the surface of the light guide plate 10. On the other hand, when the diameter exceeds 5.5 mm, the diffused light may be excessively spread and it may be difficult to perform accurate position detection. Further, when the light scattering member 45 is brought into contact with the light guide plate 10 of the coordinate input device 3, since the contact area is too large, the frictional resistance becomes too large and the operability may be impaired. As a result, if the diameter is 2.5 to 5.5 mm, the position coordinates can be detected with high accuracy while light can be diffused efficiently. In addition, a smooth writing taste, that is, a touch feeling can be realized. Note that the curved surface does not need to be configured with a uniform curvature, and the curvature may be different between the region that is the most distal end portion of the touch pen 40 and the region that surrounds the region.

  Further, the curved surface may be provided with a fine uneven shape on the surface. Light can be diffused by this fine uneven shape. Further, when the light scattering member 45 is used in contact with the light guide plate 10 of the coordinate input device 3, the contact area with the light guide plate 10 is reduced by this fine uneven shape, and the frictional force when sliding is reduced. Therefore, a smooth writing taste, that is, a touch feeling can be realized. In addition, in the case of a mode in which a fine concavo-convex shape is provided in this way, the light scattering member 45 is configured by a single resin without including a light diffusing material, and the fine concavo-convex shape in the region facing the light guide plate 10 in the resin is provided. By providing the light diffusion effect, a light diffusion effect can be achieved. In other words, if a fine uneven shape is formed in addition to including the light diffusion material, the light diffusion effect can be further enhanced. The fine uneven shape can be formed by molding, but is not limited to this method. Although the contact area with the light guide plate 10 is reduced by providing a fine concavo-convex shape, the reduction in the amount of introduced light is about 5%, so that the position coordinate detection is not greatly affected.

  Further, the light emitting surface of the light scattering member 45 is preferably subjected to wear resistance processing. This is unnecessary when the light scattering member 45 is made of a fluororesin such as polytetrafluoroethylene, but when the light scattering member 45 itself is made of another material that is not excellent in wear resistance. It is effective to subject the light emitting surface to wear-resistant processing. Although there is no restriction | limiting in particular with an abrasion-resistant process, For example, the process which coats fluororesins, such as polytetrafluoroethylene, on the light-projection surface of the light-scattering member 45 is mentioned.

  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. Moreover, compared with the structure which replace | exchanges touch pen 40 itself, use can be continued at low cost. Further, since it is detachable, the introduction portion 42b, which is a member to which the light scattering member 45 is attached, is provided with a groove structure, an occlusal structure, or a fitting structure at a portion in contact with the light scattering member 45. On the other hand, the light scattering member 45 is preferably provided with a structure that matches the structure. In the present embodiment, the light scattering member 45 is attached to the introduction portion 42b. However, the present invention is not limited to this, and may be an aspect in which the light scattering member 45 is attached to the housing 41, or another aspect.

  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. 2, the propagation lights 10 a and 10 b propagating through the light guide plate 10 enter the imaging units 20 and 30 through the notches 11, respectively. In the imaging units 20 and 30, an angle formed with the imaging units 20 and 30 in the two-dimensional plane of the light guide plate 10 at a location where the touch pen 40 contacts is obtained from each image obtained from the imaging element 13. 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. 1 and 2 and FIGS. 5 (a) and 5 (b). FIG. 5A is a perspective view illustrating an imaging state of the imaging unit 20 in the coordinate input device 3, and FIG. 5B is a plan view illustrating an image of the imaging element 23 of the imaging unit 20.

As shown in FIG. 2, 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, 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
sinθ _P <1 / N
The light flux that satisfies the conditions shown in FIG. 5 is confined in the light guide plate 10, and is repeatedly reflected on the front and back surfaces of the light guide plate 10, and travels in the light guide plate 10.

  Here, as shown in FIG. 1, 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. The propagating lights 10a and 10b in a part of the luminous flux are also guided to the end face of the conical cutout 11, and the reflected light of the end face is received by the imaging units 20 and 30. Specifically, the reflected light on the end face of the notch 11 is collected by the lenses 21 and 31, and then passes through the visible light cut filters 22 and 32 and finally received by the image sensors 23 and 33. . 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, the processing of the imaging units 20 and 30 will be described with reference to FIGS. 5A and 5B, only the imaging unit 20 will be described, but the same processing is performed in the imaging unit 30 as well.

  As shown in FIGS. 1 and 5A, the light incident on the imaging units 20 and 30 passes through lenses 21 and 31 to form a linear image 25 on the imaging elements 23 and 33. 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 10a and 10b 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. 5 (a), the case where the touch pen 40 is in the position of point P _1, as shown in FIG. 5 (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 in the state of 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 10a 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. 5B changes depending on the position of the contact point at the pen tip of the touch pen 40, and when the position of the contact point of the pen tip is changed, the linear image 25 becomes 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 23, 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 23 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 3.

  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.

(Coordinate position calibration using calibration light source and coordinate correction based on calibration values)
The coordinate input device 3 of the present embodiment includes a light guide plate 10, and propagating light 10 a and 10 b propagating through the light guide plate 10 by bringing the touch pen 40 into contact with the surface of the light guide plate 10 by the imaging elements 23 and 33. It detects and detects the coordinates of the contact position of the touch pen 40 on the surface of the light guide plate 10.

  In the optical coordinate input device 3 including such a light guide plate 10, the light guide plate 10 may be expanded or contracted or displaced in use. That is, since the light guide plate 10 is made of acrylic, for example, it expands and contracts due to expansion. In addition, when the coordinate input system 1 is dropped, the relationship between the light guide plate 10 and the liquid crystal display panel 2 may be misaligned compared to the time of shipment. In that case, the positional relationship between the touch pen 40 and the image sensors 23 and 33 is shifted, and the coordinate detection accuracy is lowered.

  In order to prevent the deterioration of the coordinate detection accuracy, for example, when the operation tool is the touch pen 40 having the light emitting unit 42 as in the coordinate input device 3 of the present embodiment, the touch pen 40 is predetermined. It is conceivable to calibrate the positional relationship between the touch pen 40 and the image pickup devices 23 and 33, that is, to calibrate the coordinate position by contacting the touched position. However, such a calibration method requires the user to bring the touch pen into contact with a predetermined position, which is cumbersome and burdensome for the user.

  Therefore, in the present embodiment, the following configuration is provided to calibrate the contact position of the touch pen 40 on the surface of the light guide plate 10 that accompanies expansion and contraction and displacement of the light guide plate 10.

First, as shown in FIGS. 6A and 6B, a calibration light source 4 is provided below the light guide plate 10 so that light enters the light guide plate 10 from a known accurate coordinate position on the light guide plate 10. It has been.
A plurality of calibration light sources 4 are provided near the end of the light guide plate 10, for example. In the present invention, the number of calibration light sources 4 is not limited to a plurality, and may be one. Also, the calibration light source 4 may be installed at the center instead of the vicinity of the end portion of the light guide plate 10.

  As the calibration light source 4, for example, an LED or an LD that emits light such as infrared light can be used. Further, the calibration light source 4 may be configured such that light is incident on the light guide plate 10 by lighting a part of the liquid crystal display panel 2. According to this configuration, it is not necessary to provide the calibration light source 4 separately.

  As shown in FIG. 1, the coordinate input system 1 is provided with a coordinate calibration correction unit 50 including a CPU.

  The coordinate calibration correction unit 50 compares the coordinates of the incident position of the light in the calibration light source 4 detected by turning on the calibration light source 4 with the known accurate coordinates in the calibration light source 4, and the amount of positional deviation. It has the function as the coordinate calibration means of this invention which calculates | requires.

  The coordinate calibration correction unit 50 is configured to correct the detected coordinates based on the amount of displacement when the touch pen 40 is brought into contact with the surface of the light guide plate 10 and the coordinates of the contact position are detected. It has a function as the coordinate correction means of the present invention.

  A coordinate calibration method using the calibration light source 4 and a coordinate correction method based on the calibration will be described with reference to FIG. FIG. 7 is a main flowchart showing a coordinate calibration method using the calibration light source 4 and a coordinate correction method based on the calibration.

  As shown in FIG. 7, a coordinate calibration method using the calibration light source 4 and a coordinate correction method based on the calibration include a preparation step (S1) performed before shipment, a coordinate calibration step (S2) performed after shipment, and It is roughly divided into a coordinate correction step (S3).

  In the preparatory step (S1), a process for obtaining the exact coordinate position of the installed calibration light source 4 on the light guide plate 10, or correctly, the position of the incident light on the light guide plate 10 of the calibration light source 4 is performed (S1). ). Specifically, before the coordinate input system 1 is shipped, calibration is performed in advance by a human hand, and the position, that is, the angle of the calibration light source 4 viewed from the image sensors 23 and 33 when the calibration is accurate is recorded. Keep it.

  Then, after shipment, in the coordinate calibration step (S2), the calibration light source 4 is turned on when the coordinate input system 1 is turned on, and the calibration light source coordinate detection step and the positional deviation amount calculation step are performed. Then, when the actual touch pen 40 is in contact with the light guide plate 10, a coordinate correction step (S3) is performed based on the calculated displacement amount.

  The flow of the coordinate calibration process will be described with reference to FIG. FIG. 8 is a subroutine flowchart showing the flow of the coordinate calibration process.

  As shown in FIG. 8, after the coordinate input system 1 is shipped, the coordinate input system 1 is powered on (S11). Next, the calibration light source 4 is turned on to emit light for a predetermined time (S12). In this process, the calibration light source 4 is preferably turned on in synchronization with the power supply of the coordinate input system 1 being turned on.

  Thereby, the light from the calibration light source 4 enters the light guide plate 10, the propagating lights 10 a and 10 b propagating through the light guide plate 10 are detected by the image sensors 23 and 33, and the light incident position in the calibration light source 4 is detected. Coordinates are detected (S13).

  S11 to S13 correspond to the calibration light source coordinate detection step.

  Next, as the positional deviation amount calculation step, the coordinates of the incident position of the light in the calibration light source 4 obtained in the calibration light source coordinate detection step (S11 to S13) and the calibration obtained in the preparation step (S1). The positional deviation amount is calculated by comparing with the exact coordinates in the light source 4 (S14).

  Here, in the present embodiment, while the power of the coordinate input system 1 is turned on, for example, the processes of S12 to S14 are performed at regular intervals of one hour. Thereby, even if the light guide plate 10 expands with time due to the lighting of the liquid crystal display panel 2, coordinate detection with high accuracy can be performed regardless of the expansion.

  Next, the flow of the coordinate correction process will be described with reference to FIG. FIG. 9 is a subroutine flowchart showing the flow of the coordinate correction process.

  In the coordinate correction process, as shown in FIG. 9, the touch pen 40 is brought into contact (S21). Thereby, the light from the touch pen 40 enters the light guide plate 10, and the propagating lights 10 a and 10 b propagating through the light guide plate 10 are detected by the imaging elements 23 and 33, and the touch position on the surface of the light guide plate 10 in the touch pen 40. Are detected (S22).

  Next, the detected coordinates are corrected based on the positional deviation amount calculated in the positional deviation amount calculation step (S23).

  Here, specific processing in the coordinate calibration process and the coordinate correction process will be described. For example, when there is one calibration light source 4, the amount of misalignment is calculated by proportional distribution of the distance between the installation position of the calibration light source 4 and the imaging elements 23 and 33 except for the installation position of the calibration light source 4. Is done.

  Further, when there are a plurality of calibration light sources 4, the amount of positional deviation at each calibration light source 4 is obtained. Then, the width of the positional deviation amount can be obtained by correlation. For example, an average value of the respective positional deviation amounts can be used as the positional deviation amount. Alternatively, for example, the light guide plate 10 is partitioned in a lattice shape, and one calibration light source 4 is installed in each partition, and the amount of positional deviation is obtained. When the touch pen 40 is brought into contact with the section, it is possible to correct the detected coordinates of the touch pen 40 using the positional deviation amount in the section.

  As described above, the coordinate input device 3 according to the present embodiment includes the light guide plate 10, and transmits the propagation light 10 a and 10 b propagating through the light guide plate 10 by bringing the operation tool into contact with the surface of the light guide plate 10. Detecting at 33, the coordinates of the contact position of the operation tool on the surface of the light guide plate 10 are detected. Then, a calibration light source that is provided at a predetermined position and allows light to enter from the surface of the light guide plate 10 in order to calibrate the contact position of the operation tool with the surface of the light guide plate 10 that accompanies expansion and contraction and displacement of the light guide plate 10. 4 and the coordinates of the light incident position in the calibration light source 4 detected by turning on the calibration light source 4 and the known accurate coordinates in the calibration light source 4 to obtain a positional deviation amount A calibration correction unit 50 and a coordinate calibration correction unit 50 that corrects the detected coordinates based on the amount of displacement when the operation tool is brought into contact with the surface of the light guide plate 10 to detect the coordinates of the contact position are provided. ing.

  As a result, at the time of calibration, the coordinates serving as a reference are not automatically detected by the user and are automatically detected from a fixed location. For this reason, a user's burden does not generate | occur | produce.

  In addition, if an infrared light shielding type coordinate input device is employed, if an object such as a finger other than the touch pen touches the detection area during calibration, the infrared light in the vicinity thereof is blocked. Therefore, there is a risk of malfunction. However, in the present embodiment, the coordinate input device 3 using the light guide plate 10 is employed, and light from the calibration light source 4 is incident on the light guide plate 10. For this reason, since light does not pass through the air, calibration is not inaccurate due to external influences such as a finger during calibration.

  Therefore, in the optical coordinate input device 3 that uses the light guide plate 10, the coordinate input device that can automatically calibrate and correct the detected coordinates accompanying the expansion or contraction of the light guide plate 10 and prevent a decrease in coordinate detection accuracy. 3 can be provided.

  Further, in the coordinate input device 3 of the present embodiment, the touch pen 40 as an operation tool has a light emitting unit 42 that makes light incident on the light guide plate 10 by making contact with the surface of the light guide plate 10. The light guide plate 10 emits propagating light 10a and 10b that is incident from the touch pen 40 and guides the inside of the light guide plate 10 to the image pickup devices 23 and 33 provided in at least two locations, respectively. A notch 11 is provided as a part.

  Thereby, light is emitted from the light emitting unit 42 in the touch pen 40 as an operation tool. The light is incident on the light guide plate 10, and the propagation lights 10 a and 10 b are respectively emitted to the outside of the light guide plate 10 through the notches 11 provided in at least two places, and image pickup devices 23 provided in at least two places.・ Linearly emitted to 33 respectively.

  For this reason, in each image pick-up element 23 * 33, the space | interval L between each image pick-up element 23 * 33 in the triangle which connects each image pick-up element 23 * 33 and the contact position to the light guide plate 10 of the touch pen 40, and two angle (alpha) * (beta). Therefore, the coordinates of the contact position of the touch pen 40 with respect to the light guide plate 10 can be obtained by the triangulation method.

  Accordingly, the coordinate input device 3 is provided which uses the light guide plate 10 and makes light incident on the light guide plate 10 from the touch pen 40 to obtain the coordinates of the contact position of the touch pen 40 on the light guide plate 10 by triangulation. be able to.

  In addition, the coordinate correction method of the coordinate input device 3 according to the present embodiment includes the light guide plate 10, and transmits the propagation lights 10 a and 10 b propagating through the light guide plate 10 by bringing an operation tool into contact with the surface of the light guide plate 10. 23 is a coordinate correction method of the coordinate input device 3 that detects the coordinates of the position of contact with the surface of the light guide plate 10 in the operation tool. Then, in the power-on state of the coordinate input device 3, the light of the calibration light source 4 is made incident on the light guide plate 10 by turning on the calibration light source 4 provided at a known accurate coordinate position on the light guide plate 10. A calibration light source coordinate detection step of detecting the propagation light 10a and 10b propagating through the light guide plate 10 by the image sensors 23 and 33 and detecting the coordinates of the light incident position in the calibration light source 4, and the calibration light source coordinates The positional deviation amount calculating step for obtaining the positional deviation amount by comparing the coordinates of the light incident position in the calibration light source 4 obtained in the detection step with the known accurate coordinates in the calibration light source 4 and the operation tool are brought into contact with each other. When the propagating lights 10a and 10b propagating through the light guide plate 10 are detected by the image sensors 23 and 33, and the coordinates of the contact position of the operation tool with the surface of the light guide plate 10 are detected, And a coordinate correction step of correcting the detected coordinates on the basis of which the amount.

  As a result, in the optical coordinate input device 3 that uses the light guide plate 10, coordinate input that can automatically calibrate and correct the detected coordinates accompanying the expansion or contraction of the light guide plate 10 to prevent a decrease in coordinate detection accuracy. A coordinate correction method for the device 3 can be provided.

  Further, in the coordinate correction method of the coordinate input device 3 of the present embodiment, the calibration light source coordinate detection step and the positional deviation amount calculation step are performed when the power of the coordinate input device 3 is turned on and thereafter at regular intervals. .

  Thus, when the power of the coordinate input device 3 is turned on, the light guide plate 10 is automatically calibrated in the calibration light source coordinate detection step and the positional deviation amount calculation step. As a result, when the coordinate input device 3 is dropped when the power of the coordinate input device 3 is turned off and the light guide plate 10 is misaligned, the detection is possible even when the operator does not know the fact. It is possible to provide a coordinate correction method for the coordinate input device 3 that can automatically calibrate and correct the coordinates to prevent a decrease in coordinate detection accuracy.

  In the present embodiment, the calibration light source coordinate detection step and the positional deviation amount calculation step are performed at regular intervals while the power supply of the coordinate input device 3 is turned on.

  For this reason, even when the light guide plate 10 is expanded due to thermal expansion due to long-time use of the coordinate input device 3, the coordinates that can automatically calibrate and correct the detected coordinates to prevent a decrease in coordinate detection accuracy. A coordinate correction method for the input device 3 can be provided.

  A coordinate input system 1 according to the present embodiment is a coordinate input system 1 including the coordinate input device 3 according to the present embodiment, and includes a liquid crystal display panel 2. For this reason, the coordinate input device 3 can be made to function as a touch panel which inputs with the touch pen 40, seeing the image of the liquid crystal display panel 2. FIG. Therefore, in the optical coordinate input device 3 that uses the light guide plate 10, the coordinate input device that can automatically calibrate and correct the detected coordinates accompanying the expansion or contraction of the light guide plate 10 and prevent a decrease in coordinate detection accuracy. The coordinate input system 1 with 3 can be provided.

  In addition, this invention is not limited to said embodiment, A various change is possible within the scope of the present invention. For example, in the above embodiment, the touch pen 40 as an operation tool having the light emitting unit 42 is contacted with the light guide plate 10 to detect the coordinates of the contact position. However, in the present invention, the present invention is not necessarily limited thereto. For example, as shown in FIGS. 10 and 11, the finger 60 as an operation tool is contacted with the light guide plate 10 to detect the coordinates of the contact position. Is possible. In this case, as shown in FIGS. 10 and 11, the light source unit 5 is provided around the light guide plate 10.

  That is, the coordinate input device 3 is provided around the at least one side of the light guide plate 10 along the one side with a light source unit 5 in which LEDs 5a serving as a plurality of light sources that allow light to enter the light guide plate 10 are arranged. The light guide plate 10 serves as an optical path conversion unit that linearly emits propagating light that enters from the plurality of LEDs 5a and guides the inside of the light guide plate 10 to the image pickup devices 23 and 33 provided in at least two places. A notch 11 is provided. The operation tool includes a finger 60 that attenuates the amount of propagating light in the light guide plate 10 by being brought into contact with the surface of the light guide plate 10. Further, it can be assumed that some of the LEDs 5a in the plurality of LEDs 5a can be used as calibration light sources.

  In the coordinate input device 3 having this configuration, light is incident on the light guide plate 10 from a plurality of LEDs 5 a provided along the periphery of at least one side of the light guide plate 10. The light incident on the light guide plate 10 is guided as propagating light inside the light guide plate 10, and is emitted linearly to the image pickup devices 23 and 33 provided in at least two places through the notches 11. At this time, when the finger 60 as an operation tool is brought into contact with the surface of the light guide plate 10, the propagation light at the contact position is disturbed, and scattered light is generated. Part of this scattered light also propagates in the direction of the image sensors 23 and 33 and is received by the image sensors 23 and 33. As a result, the azimuth angle is measured from the linear images of the image sensors 23 and 33 and the scattered light is generated by the triangulation method, that is, the coordinates of the contact position of the finger 60 with the light guide plate 10. Is identified.

  Therefore, it is possible to provide a coordinate input device 3 that uses the light guide plate 10 to obtain the coordinates of the contact position of the finger 60 on the light guide plate 10 by triangulation by bringing the finger 60 into contact with the light guide plate 10. it can.

  In the present embodiment, a part of the plurality of LEDs 5a can be used as a calibration light source. For this reason, even if the calibration light source 4 is not separately provided as the calibration light source, the calibration can be performed using the existing LED 5a. Therefore, an increase in cost associated with calibration can be suppressed.

  Also, with this configuration, the coordinate input device 3 can function as a touch panel that is input with the finger 60 while viewing the image on the liquid crystal display panel 2. Therefore, in the optical coordinate input device 3 that uses the light guide plate 10, the coordinate input device that can automatically calibrate and correct the detected coordinates accompanying the expansion or contraction of the light guide plate 10 and prevent a decrease in coordinate detection accuracy. The coordinate input system 1 with 3 can be provided.

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

  The present invention includes a light guide member, and detects the propagating light propagating through the light guide member by bringing the operation tool into contact with the surface of the light guide member, and detects the surface of the light guide member in the operation tool. The present invention can be applied to an optical coordinate input device that detects the coordinates of the contact position to the coordinate system, a coordinate correction method for the coordinate input device, and a coordinate input system. Further, the coordinate input device can be applied to both a touch pen type and a finger type.

1 Coordinate input system 2 Liquid crystal display panel (image display panel)
3 Coordinate Input Device 10 Light Guide Plate (Light Guide Member)
10a Propagating light 10b Propagating light 11 Notch (optical path changing unit)
20 Imaging unit 21 Lens 22 Visible light cut filter 23 Imaging device (light receiving unit)
25 Image 27 Image 30 Imaging unit 31 Lens 32 Visible light cut filter 33 Imaging element (light receiving unit)
40 Touch pen (operation tool)
42 Light Emitting Unit 45 Light Scattering Member 50 Coordinate Calibration Correction Unit (Coordinate Calibration Unit, Coordinate Correction Unit)
60 fingers (operation tools)
L interval

Claims (5)

A light guide member is provided, and by detecting the propagating light propagating through the light guide member by bringing the operation tool into contact with the surface of the light guide member, the contact position of the operation tool with the surface of the light guide member A coordinate input device for detecting the coordinates of
A calibration light source that is provided at a predetermined position and allows light to enter from the surface of the light guide member in order to calibrate the contact position of the operation tool with the surface of the light guide member accompanying expansion and contraction of the light guide member. When,
Coordinate calibration means for comparing the coordinates of the incident position of light in the calibration light source detected by turning on the calibration light source and the known accurate coordinates in the calibration light source to obtain a positional deviation amount;
Coordinate correction means is provided for correcting the detected coordinates based on the amount of displacement when the operation tool is brought into contact with the surface of the light guide member and the coordinates of the contact position are detected. Coordinate input device. The operation tool has a light emitting unit that makes light incident on the light guide member by contacting the surface of the light guide member, and
The light guide member is provided with an optical path conversion unit that linearly emits the propagating light that is incident from the operation tool and guides the inside of the light guide member to the light receiving units provided in at least two places. The coordinate input device according to claim 1, wherein the coordinate input device is provided. A light guide member is provided, and by detecting the propagating light propagating through the light guide member by bringing the operation tool into contact with the surface of the light guide member, the contact position of the operation tool with the surface of the light guide member A coordinate correction method for a coordinate input device that detects the coordinates of
By turning on a calibration light source provided at a known accurate coordinate position in the light guide member in a power-on state in the coordinate input device, the light from the calibration light source is incident on the light guide member, A calibration light source coordinate detection step of detecting the propagation light propagating through the light guide member at the light receiving unit and detecting the coordinates of the incident position of the light in the calibration light source;
A positional deviation amount calculating step for obtaining a positional deviation amount by comparing the coordinates of the incident position of light in the calibration light source obtained in the calibration light source coordinate detection step with known accurate coordinates in the calibration light source;
When the light that propagates through the light guide member by contacting the operation tool is detected by a light receiving unit and the coordinates of the contact position of the operation tool with the surface of the light guide member are detected, the amount of displacement A coordinate correction method for a coordinate input device, comprising: a coordinate correction step of correcting detected coordinates based on   4. The coordinate correction method for a coordinate input device according to claim 3, wherein the calibration light source coordinate detection step and the positional deviation amount calculation step are performed when the power of the coordinate input device is turned on and thereafter at regular intervals. . A coordinate input system comprising the coordinate input device according to claim 1,
A coordinate input system comprising an image display panel.

Images