JP2013250814A - Coordinate input device, and coordinate input system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a coordinate input device having high position detection accuracy of a detected body.SOLUTION: A coordinate input device comprises: a plate-like light guide plate 10; an LED 4a that causes light to be made incident on the light guide plate 10; at least two imaging units; and detection unit that detects, when the surface of the light guide plate 10 is contacted by a finger, coordinates of a contact position of the finger on the surface of the light guide plate 10 on the basis of output of the imaging units that has detected scattering of light caused by the finger. The coordinate input device further includes an optical coupling member 5 that couples light beams emitted from the LED 4a to be made incident obliquely on a back face of the light guide plate 10.

Description

  The present invention includes a plate-shaped light guide member, a light source that makes light incident on the light guide member, a light receiving unit, and light scattering by the detected object when the detected object contacts the surface of the light guide member. The present invention relates to an optical coordinate input device and a coordinate input system provided with detection means for detecting the coordinates of the contact position of the detected body with the surface of the light guide member based on the detected output of the light receiving means. .

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

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

  For example, as shown in FIGS. 20A and 20B, the touch panel 100 disclosed in the first embodiment of Patent Document 1 includes a light guide plate 101, a light source 102 that makes light incident on the light guide plate 101, The light receiving elements 104 and 105 arranged on a part of the side surface of the light guide plate 101 and the light from the light source 102 scattered by the detected object 110 between the side surface of the light guide plate 101 and the light receiving elements 104 and 105 are received by the light receiving element 104. An image forming unit 107 that forms an image on 105 is provided. Further, light absorbing means 108 is disposed on the side surface of the light guide plate 101 on which the light receiving elements 104 and 105 are disposed, and the light receiving elements 104 and 105 are outside the irradiation range of the light source 102 as shown in FIG. Has been placed.

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

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

  In the third embodiment of Patent Document 1, as shown in FIGS. 22A and 22B, the light source 102a, the light receiving element 104a, the light source 102b, and the light receiving element 104b are respectively disposed on the opposite end surfaces of the light guide plate 101. There is described a touch panel 100 ′ that can be arranged and light sources 102a and 102b are alternately turned on to eliminate the influence of light directly reaching the light receiving elements 104a and 104b. Accordingly, it is possible to increase the degree of freedom of arrangement of the light sources 102a and 102b and the light receiving elements 104a and 104b.

  By the way, in such a touch panel 100 ′, there are cases where it is desired to have a plurality of detected bodies such as fingers. In such a case, when there are only two light receiving elements, as shown in FIG. 15, there are a plurality of possible combinations of contact positions on the detection target such as a finger, and the contact positions cannot be determined. In this case, by using at least three light receiving elements, it is possible to determine the contact position on the detection object such as a plurality of fingers.

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

  However, the technique of Patent Document 1 has a problem that the position detection accuracy of the detected object is low.

  In the technique of Patent Document 1, scattered light at the touch position of the detection object 110 is detected, and the more the number of times the propagation light is reflected on the surface of the light guide plate 101, the more the position detection of the detection object 110 is performed. More scattered light components contribute. In the touch panel 100 of Patent Document 1, the light source 102 is disposed on the side surface of the light guide plate 101. Therefore, the light emitted from the light source 102 is incident on the side surface of the light guide plate 101 substantially perpendicularly. Therefore, in the light guide plate 101, the light intensity of the reflection component reflected at an angle close to 0 ° with respect to the front or back surface of the light guide plate 101 is maximized. Since such a reflection component has a very small reflection angle with respect to the front surface or the back surface of the light guide plate 101, the number of total reflections in the light guide plate 101 is small. As a result, the technique of the cited document 1 has a problem that the position detection accuracy of the detected object 110 is lowered because the scattered light component contributing to the position detection of the detected object 110 is small.

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a coordinate input device and a coordinate input system with high position detection accuracy of a detection target.

  In order to solve the above problems, the coordinate input device of the present invention has a plate-shaped light guide member, a light source that makes light incident on the light guide member, at least two light receiving means, and a surface of the light guide member. Detecting means for detecting the coordinates of the contact position of the light guide member on the surface of the light guide member based on the output of the light receiving means that has detected the propagation light in the light guide member when contacting the target object; In the coordinate input device, an optical coupling member that couples the emitted light of the light source so as to be incident obliquely on the back surface of the light guide member is provided.

  According to said structure, a coordinate input device contacts a to-be-detected body to the plate-shaped light guide member, the light source which injects light into a light guide member, at least 2 light-receiving means, and the surface of the said light guide member And detecting means for detecting the coordinates of the contact position of the detected body on the surface of the light guide member based on the output of the light receiving means that detects the propagation light in the light guide member.

  In such a coordinate input device, scattered light at the touch position of the detected object is detected, and the greater the number of times the propagating light is reflected on the surface of the light guide member, the more contributed to the position detection of the detected object. More scattered light components are generated. In the touch panel of Patent Document 1, the light source is disposed on the side surface of the light guide member, and the light emitted from the light source is incident substantially perpendicular to the side surface of the light guide member. Therefore, in the light guide member, the light intensity of the reflection component reflected at an angle close to 0 ° with respect to the front surface or the back surface of the light guide member is maximized. Since such a reflection component has a very small reflection angle with respect to the front surface or the back surface of the light guide member, the number of total reflections in the light guide member is small. As a result, the technique of the cited document 1 has a problem that the position detection accuracy of the detected object is lowered because the scattered light component contributing to the position detection of the detected object is small.

  Therefore, according to the above configuration, the optical coupling member that couples the emitted light of the light source so as to be incident obliquely on the back surface of the light guide member is provided. As a result, the intensity of the reflection component of the light propagating in the light guide member is reflected at an angle close to 0 ° with respect to the front surface or back surface of the light guide member, and total reflection on the front surface or back surface of the light guide member The number of times increases. As a result, according to the above configuration, the scattered light component contributing to the position detection of the detected object increases, and a coordinate input device with high position detection accuracy of the detected object can be realized.

  In the coordinate input device according to the aspect of the invention, the light coupling member may be arranged such that the light coupling member is in contact with the light guide member and the light axis direction of the light emitted from the light source is inclined with respect to the back surface of the light guide member. It is preferable that the light source arrangement part is provided, and the light of the light source is incident on the light guide member through the contact surface.

  Thus, it is possible to reliably combine the light emitted from the light source so as to be incident obliquely with respect to the back surface of the light guide member. A coordinate input device with high position detection accuracy of the detected object can be realized.

In the coordinate input apparatus of the present invention, the light source may be propagated angle theta _p with respect to the rear surface of the light propagating through the light guide member is such that the 25 ° to 48 °, is installed in the optical coupling member preferable.

According to said structure, since the said light source is installed in the said optical coupling member so that propagation angle (theta) _p with respect to the said back surface of the light which propagates the said light guide member may be 25 degrees-48 degrees, When the material of the light guide member is acrylic resin, the amount of change in the amount of light due to scattered light generated by finger contact becomes large, and a coordinate input device with high position detection accuracy of the detection target can be realized.

  In the coordinate input device of the present invention, it is preferable that the refractive index of the optical coupling member is the same as the refractive index of the light guide member.

  Thereby, the optical loss which generate | occur | produces in the interface of an optical coupling member and a light guide member can be eliminated. As a result, according to the above configuration, the light from the light source can be efficiently optically coupled to the light guide member.

  In consideration of the material of the light guide member used in the technical field, the type of the light source, etc., the angle between the optical axis of the emitted light and the normal of the back surface of the light guide member is 45 ± 10 °. It is preferable that the optical coupling member is disposed.

  In order to solve the above-described 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 module.

  According to said structure, since the above-mentioned coordinate input device and an image display panel are provided, a coordinate input system with high position detection accuracy of a to-be-detected body is realizable.

  As described above, the coordinate input device of the present invention includes a plate-shaped light guide member, a light source that causes light to enter the light guide member, at least two light receiving means, and a detection target on the surface of the light guide member. A coordinate input device comprising: a detecting unit that obtains coordinates of a position of contact with the surface of the light guide member in the detected object based on an output of the light receiving unit that detects light scattering by the detected object when contacted; In this configuration, an optical coupling member that couples the emitted light of the light source so as to be incident obliquely with respect to the back surface of the light guide member is provided.

  Moreover, the coordinate input system of this invention is a coordinate input system provided with the said coordinate input device as mentioned above, Comprising: It is the structure provided with the image display module.

  Therefore, there is an effect that the position detection accuracy of the detection object is high.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an embodiment of a coordinate input device and a coordinate input system according to the present invention, and a lighting control method for a light source unit in the coordinate input device. It is a disassembled perspective view which shows the structure of the said coordinate input system. (A) is a top view which shows the structure of a coordinate input system, (b) is side sectional drawing which shows the structure of a coordinate input system. (A) is a side view which shows the structure of a coordinate input system, (b) is a principal part side view which expands and shows the structure of the edge part of a coordinate input system. FIG. 8 shows a configuration of a coordinate input system, and is a cross-sectional view taken along line AA in FIG. 7. It is a top view which shows the irradiation area | region to the light-guide plate in one LED. It is a perspective view which shows the optical path of scattered light when a finger touches a light-guide plate. (A)-(c) is sectional drawing which shows the structure of the optical coupling member provided between the light-guide plate and LED. It is a graph which shows the result of having verified the setting of propagation angle (theta) _p which contributes to finger position detection of the light which propagates a light guide plate, and shows the relationship between the light quantity change by the finger contact of a light guide plate, and propagation angle (theta) _p . It is a top view which shows the positional relationship of a light source unit and an imaging unit, and sectional drawing which shows the structure of the optical coupling member in the light source unit shown by this top view. (A) is a top view which shows the detection principle of a coordinate input device, (b) is a wave form diagram which shows the optical signal of the image pick-up element in the imaging unit of a coordinate input device. (A) is a top view which shows the contact position when a finger | toe contacts the various places in the surface of a light-guide plate, (b) is the pixel number which appears in the detection image of an image pick-up element corresponding to the contact position of this finger | toe It is a wave form diagram which shows the relationship with signal strength. (A) is a perspective view which shows the imaging condition in the imaging unit in the said coordinate input device, (b) is a top view which shows the image in the image pick-up element of the said imaging unit. FIG. 10 is a plan view showing another embodiment of the coordinate input device according to the present invention and showing a state in which a finger is brought into contact with a proximity position of an imaging unit. It is a top view which shows the malfunction when a finger | toe is simultaneously contacted at two places when two imaging units are provided in one 1st edge part of the light-guide plate. It is a perspective view which shows the structure of the coordinate input device in said other embodiment. It is a top view which shows the lighting control method of the light source unit of the coordinate input device in said other embodiment. In the coordinate input device in the other embodiment, it is a plan view showing a detection method when a finger is brought into contact with the proximity position of the imaging unit. It is a top view which shows the detection method when the several finger | toe is contacted with the light-guide plate in the coordinate input device in the said other embodiment. (A) is a perspective view which shows the structure of the position detection apparatus as a conventional coordinate input device, (b) is a top view which shows the structure of the principal part of the said position detection apparatus. (A) is a top view which shows the detection principle of the position detection apparatus as the said conventional coordinate input device, (b) is a wave form diagram which shows the optical signal of the light receiving element in the said position detection apparatus. (A) and (b) are the top views which show the structure of the modification in the position detection apparatus as said conventional coordinate input device, and show the lighting control method of a light source.

  The coordinate input device according to the present invention includes a plate-shaped light guide member, a light source that makes light incident on the light guide member, at least two light receiving means, and a guide when a detected object comes into contact with the surface of the light guide member. Based on the output of the light receiving means that has detected the propagation light in the optical member, the detection means detects the coordinates of the contact position of the detected body to the surface of the light guide member. In the coordinate input device of the present invention, when the detected object comes into contact with the surface of the light guide member, the light receiving means detects the propagation light in the light guide member due to the contact. And a detection means detects the coordinate of the contact position to the surface of the light guide member in a to-be-detected body based on the output of a light-receiving means.

  Here, the “output of the light receiving means” detected by the detecting means refers to the output of the light receiving means when the detected body is not in contact with the surface of the light guide member and the detected body in contact with the surface of the light guide member. This means an output image in which the output difference from the output of the light receiving means can be identified. Therefore, the “output of the light receiving means” means that the output of the light receiving means when the detected body is brought into contact with the surface of the light guide member is the light receiving means when the detected body is not in contact with the surface of the light guide member. Output of the light receiving means when the detected object is in contact with the surface of the light guide member and the output of the light receiving means when the detected object is not in contact with the surface of the light guide member And both smaller output images.

  Moreover, the to-be-detected body should just identify the said output difference by contacting the surface of a light guide member, for example, a finger | toe, a stick-shaped touch pen, a light emitting pen etc. are mentioned.

  In the following embodiments, the output of the light receiving means when the detected body is a finger and the detection means detects that the output of the light receiving means is in contact with the surface of the light guide member. An explanation will be given by taking as an example a configuration in which the output image is larger than the output of the light receiving means when the detection object is not in contact with the surface of the optical member. In this case, the “output of the light receiving means” is “the output of the light receiving means that detects light scattering by the detected object when the detected object is in contact with the surface of the light guide member”, and more specifically, It is a light reception peak of scattered light due to the presence of the detection target.

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

(Configuration of coordinate input system)
A configuration of a coordinate input system including the coordinate input device according to the present embodiment will be described with reference to FIGS. 2 and 3A and 3B. FIG. 2 is an exploded perspective view showing the configuration of the coordinate input system. FIG. 3A is a plan view showing the configuration of the coordinate input system, and FIG. 3B is a side sectional view showing the configuration of the coordinate input system. In this specification, the Z direction in FIG. 2 is the front side of the coordinate input system. 2 is the longitudinal direction of the coordinate input system, and the Y direction in FIG. 2 is the short direction of the coordinate input system.

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

  As shown in FIGS. 3A and 3B, the liquid crystal display module 2 has a liquid crystal layer sandwiched between a pair of substrates (not shown), and the liquid crystal molecules of the liquid crystal layer are aligned on each substrate by voltage application. And a liquid crystal display panel 2a provided with various electrodes for changing. In the liquid crystal display panel 2a, a desired display is performed by adjusting the amount of light transmitted through the liquid crystal layer of each pixel by changing the orientation of the liquid crystal molecules by applying a voltage between the electrodes. The liquid crystal display panel 2a is supported by the chassis 2b, and a protective glass 2c is provided on the front surface of the liquid crystal display panel 2a. Note that a conventionally known liquid crystal display module can be used as the configuration of the liquid crystal display module 2.

  In the coordinate input system 1, for example, a finger as a detection object is brought into contact with the light guide plate 10 of the coordinate input device 3 </ b> A provided on the front side of the liquid crystal display panel 2 a while viewing the screen displayed on the liquid crystal display panel 2 a. Thus, the coordinates of the contact position on the finger 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 below with reference to FIG. 2, FIG. 3 (a) (b), and FIG. 4 (a) (b) to FIG. Detailed description. 4A is a side view showing the configuration of the coordinate input system 1, and FIG. 4B is an enlarged side view showing the configuration of the edge of the coordinate input system 1. As shown in FIG. FIG. 5 shows a configuration of the coordinate input system 1, and is a cross-sectional view taken along line AA in FIG. FIG. 6 is a plan view showing an irradiation area to the light guide plate 10 in one LED. FIG. 7 is a perspective view showing an optical path of scattered light when the finger 8 touches the light guide plate 10. 8A and 8B are cross-sectional views showing the configuration of the optical coupling member provided between the light guide plate 10 and the LED 4a.

  As shown in FIGS. 2 and 3A and 3B, the coordinate input device 3 </ b> A is disposed at a corner portion of the light guide plate 10 as a rectangular transparent light guide member and the rectangular light guide plate 10. From the image pickup units 20, 30, 40, 50 as the received light receiving means, the light source units 4A, 4B as the light sources provided on the back sides of both sides in the longitudinal direction of the light guide plate 10, and the light source units 4A, 4B An optical coupling member 5 that couples light to the light guide plate 10 and a detection unit 6 as detection means described later are provided. Moreover, as shown in FIG.3 (b), the light absorption members 7 and 7 are provided in the surface side and back surface side of the location in which the light source unit 4A * 4B in the edge part in the light-guide plate 10 is arrange | positioned. .

  The light guide plate 10 is made of a single rectangular flat plate made of a translucent material, and is disposed on the display surface side of the liquid crystal display panel 2 a in the liquid crystal display module 2. The light guide plate 10 does not have to be a complete rectangle, and as will be described later, through holes 11 are formed in corners, corners are notched, or corners are curved. It may be a substantially quadrangular shape.

  As shown in FIGS. 3A and 3B, the size of the light guide plate 10 is configured such that the periphery of the four sides is larger than the liquid crystal display panel 2a. Accordingly, the imaging units 20, 30, 40, and 50 can be disposed on the back side of the light guide plate 10. As a result, an increase in the size of the coordinate input device 3A in the direction of spreading along the contact surface with the light guide plate 10 of the finger 8 described later is suppressed, which contributes to the realization of the compact size of the coordinate input device 3A. The size of the rectangular light guide plate 10 may be, for example, a diagonal of 60 inches, but is not limited thereto. For example, it may be larger, such as 60 inches, 70 inches, 80 inches, or 60 inches or less.

  The thickness of the light guide plate 10 is mainly 1 to 3 mm. However, it may be thicker than this. In the present embodiment, the thickness is 3 mm, for example. As a material of the light guide plate 10, for example, acrylic is used, and polycarbonate or glass may be used.

  Further, at the four corners of the light guide plate 10 where the imaging units 20, 30, 40, 50 are disposed, as shown in FIGS. 4 (a) and 4 (b), a concave conical optical path conversion unit is provided. The through-holes 11 are respectively formed. In addition, in this Embodiment, although the through-hole 11 is comprised by the conical surface shape, this invention is not limited to this, You may be comprised by the hyperboloid shape or the polygonal surface shape. Further, the central portion of the through hole 11 does not necessarily have to penetrate. The slope may be formed up to the middle of the thickness of the light guide plate 10. In this case, since the imaging units 20, 30, 40, and 50 are sealed, no foreign matter is mixed into the imaging units 20, 30, 40, and 50.

  As shown in FIG. 5, the angle γ formed between the conical wall surface 11a of the through hole 11 and the back surface of the light guide plate 10 is 45 degrees or less, and for example, 30 degrees or 24 degrees is selected. A mirror coating is applied to the conical surface wall surface 11 a in the through hole 11. As a result, as shown in FIG. 5, the optical path of the light propagating through the inside of the light guide plate 10 and reaching the through hole 11 is changed by the through hole 11 below the light guide plate 10, that is, toward the back surface of the light guide plate 10. Let Even if the wall surface 11 a is not mirror-coated, the optical path can be changed below the light guide plate 10 by the conical surface of the through hole 11. In the present embodiment, since the light conversion member is provided as the through hole 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.

  Next, the imaging units 20, 30, 40, and 50 are disposed immediately below the conical surface through holes 11 at the four corners of the light guide plate 10. Thus, the imaging units 20, 30, 40, and 50 have a structure that does not protrude above the surface of the light guide plate 10.

  Further, in the coordinate input device 3 </ b> A of the present embodiment, the imaging units 20, 30, 40, and 50 are provided at four corners of the light guide plate 10 that are separated from each other. However, in the present invention, the installation locations of the imaging units 20, 30, 40, and 50 are not necessarily limited to the corners. For example, imaging units 20 and 30 are provided in at least two locations on one first edge along the longitudinal direction of the light guide plate 10, and the other of the other edges of the light guide plate 10 facing the first edge. It can be assumed that the imaging units 40 and 50 are provided in at least two places on the second edge. As will be described later, in the coordinate input device 3A of the present embodiment, the reason is that the imaging units 20 and 30 on one first edge of the light guide plate 10 and the second edge of the other side of the light guide plate 10 This is because the imaging units 40 and 50 are used alternately. That is, since triangulation requires at least two light receiving means, two or more imaging units 20 and 30 and imaging units 40 and 50 are provided on each of the first edge and the second edge. It is necessary to provide it.

  As shown in FIG. 5, the imaging units 20 and 40 include lenses 21 and 41, optical filters 22 and 42, and imaging elements 23 and 43. Similarly, the imaging unit 30 also includes a lens 31, an optical filter 32, and an imaging element 33, as shown in FIG. Furthermore, although the imaging unit 50 is not shown, it has the same configuration.

  The optical filters 22 and 42 shown in FIG. 5 transmit the light in the wavelength band emitted from the finger 8 and play the role of blocking the light in the other wavelength bands. The optical filters 22 and 42 and the like block sunlight and stray light such as backlight light for a liquid crystal display panel, and can increase the SN ratio. However, in the detection of scattered light due to the contact of the finger 8, it is sufficient to take a difference from the background video signal, so an optical filter is not necessarily required.

  In addition, the image pickup devices 23, 33, 43, and the like according to the present embodiment are composed of, for example, a two-dimensional image sensor. However, the image sensor is not necessarily limited to two dimensions, and may be a one-dimensional image sensor. Alternatively, a CMOS (Complementary Metal Oxide Semiconductor) camera may be used.

  The light receiving surfaces of the image pickup devices 23, 33, and 43 are arranged so as to be parallel to the surface of the light guide plate 10.

  The imaging units 20, 30, 40, and 50 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, 33, and 43.

  Next, the light source units 4A and 4B provided at the edges of both sides in the longitudinal direction of the light guide plate 10 are each provided with a plurality of LEDs 4a ... arranged in series, as shown in FIG. Each LED 4a emits light such as infrared light. However, it is not necessarily limited to infrared light, and may be visible light or ultraviolet light. Further, it is not always necessary to use the LED 4a, and an LD (laser diode) or the like can also be used.

  Here, in the present embodiment, the light source units 4 </ b> A and 4 </ b> B are provided at the edges of both sides in the longitudinal direction of the light guide plate 10. That is, in the coordinate input device 3A of the present embodiment, the imaging units 20 and 30 and the light source unit 4A are provided on one first edge along the longitudinal direction of the light guide plate 10, and the imaging units 40 and 50 and the light source unit 4B are respectively provided on the other second edge facing the first edge. In this case, since the light source units 4A, 4B and the imaging units 20, 30, 40, 50 are all provided on the back side of the light guide plate 10, the light source units 4A, 4B are the imaging units 20, 30 or imaging units. 40 and 50 are provided between the imaging unit 20 and the imaging unit 30 or between the imaging unit 40 and the imaging unit 50 so that they do not overlap. Further, as shown in FIG. 5, the light source unit 4 </ b> A is provided near the outer peripheral end of the light guide plate 10 compared to the imaging unit 20, and the light source unit 4 </ b> B is compared to the imaging unit 40. It is provided in the vicinity of the outer peripheral end of the light guide plate 10. Therefore, in the imaging units 20, 30, 40, and 50, direct light from the light source units 4 and 4 does not enter the signal detection effective area of the imaging units 20, 30, 40, and 50. Further, the light guide plate 10 is not cut or attached to the portion outside the signal detection effective area, or the light absorbing member 7 is attached, or the through hole 11 that is an optical path changing portion is not formed outside the signal detection effective area. This is preferable because unnecessary light can be reliably blocked.

  As described above, the light source units 4 </ b> A and 4 </ b> B are preferably provided on the first edge and the second edge on both sides along the longitudinal direction of the light guide plate 10. The reason for this is that, as shown in FIG. 6, the LED 4 a is provided on both sides along the longitudinal direction of the light guide plate 10 and on the second edge, and the edges of both sides along the short side of the light guide plate 10. This is because the light reaching distance of the LED 4a in the light guide plate 10 is shorter than the case where the light guide plate 10 is provided. That is, this increases the amount of light from the light source units 4A and 4B, and also reduces the distance from the finger 8 in contact with the light guide plate 10 to the imaging units 20, 30, 40, and 50. This is because the detection intensity of the scattered light from the finger 8 at the imaging units 20, 30, 40, and 50 increases.

  Here, when the scattered light from the finger 8 is detected by the imaging devices 23, 33, 43, etc., it is necessary to increase the output of the scattered light from the imaging devices 23, 33, 43, etc. as much as possible. For this purpose, it is preferable that the amount of propagating light from the LED 4a inside the light guide plate 10 is larger. Therefore, as shown in FIG. 6, the radiation angle δ of one LED 4a is made small. This is because when the radiation angle δ of the LED 4a is large, the light amount density of the irradiation region in one LED 4a decreases.

  Further, as shown in FIG. 7, the coordinate input device 3A is provided with a detection unit 6 as detection means. The detection unit 6 detects outputs from the image pickup devices 23 and 33 based on light scattering by the finger 8 and obtains coordinates of a contact position of the finger 8 on the surface of the light guide plate 10. Specifically, it consists of a CPU.

  Further, light absorbing members 7 and 7 are provided on the first edge and the second edge of the light guide plate 10 so as not to overlap the light source units 4A and 4B and the imaging units 20, 30, 40, and 50. Yes. The light absorbing members 7 and 7 are formed by sticking a high light-shielding film made of, for example, a black polyester film or the like to the light guide plate 10 so that the reflected light at the end of the light guide plate 10 returns to the opposite end. So that the reflected light is absorbed.

  Here, in the coordinate input system 1 of this Embodiment, the finger | toe 8 is used as a to-be-detected body, for example. However, the detection target is not necessarily limited to the finger 8 and may be a detected object such as a stick-shaped touch pen.

(Configuration of optical coupling member 5)
Here, in the present embodiment, the light source units 4 </ b> A and 4 </ b> B are disposed on the back side of the light guide plate 10. In this case, if the light from the LEDs 4a of the light source units 4A and 4B is incident on the light guide plate 10 perpendicularly, the incident light does not guide the inside of the light guide plate 10 and passes through the front surface of the light guide plate 10 as it is. To go. Therefore, in the present embodiment, as shown in FIG. 2, optical coupling members 5 and 5 are provided between the light guide plate 10 and the light source units 4A and 4B, as shown in FIGS. As described above, the light from the LEDs 4a of the light source units 4A and 4B is incident on the back surface of the light guide plate 10 through the optical coupling members 5 and 5 at an angle. More specifically, the optical coupling member 5 has a contact surface that is in contact with the light guide plate 10 via the double-sided tape 5b or an adhesive, and an optical axis direction of light emitted from the LED 4a is inclined with respect to the back surface of the light guide plate 10. And a light source arrangement part for arranging the LEDs 4a. And the optical coupling member 5 makes the emitted light of LED4a inject into the light-guide plate 10 through the said contact surface (double-sided tape 5b or adhesive agent).

  As a result, the intensity of the reflection component of the light propagating in the light guide plate 10 is reflected at an angle close to 0 ° with respect to the front or back surface of the light guide plate 10, and the total reflection on the front or back surface of the light guide plate 10 is thereby achieved. The number of times increases. As a result, the scattered light component contributing to the position detection of the detected object increases, and a coordinate input device with high position detection accuracy of the detected object can be realized.

  Specifically, as shown in FIG. 8A, the optical coupling member 5 can be composed of, for example, a triangular prism block 5a. The block 5a can be bonded to the light guide plate 10 with, for example, a double-sided tape 5b or an adhesive. And LED4a is adhere | attached on the inclined surface 5c (light source arrangement | positioning part) of this block 5a, and the optical axis of the emitted light of LED4a is made to incline with respect to the back surface of the light-guide plate 10. FIG. Thereby, the emitted light of LED4a can be made incident on the light-guide plate 10 diagonally as shown to Fig.8 (a).

  As shown in FIG. 8B, when a bullet-type LED 4 a is used as the LED 4 a, a transparent block 5 a that can fix the bullet-type LED 4 a obliquely with respect to the light guide plate 10 as the optical coupling member 5. 'Can be used. The block 5a 'has a housing part 5c' (light source arrangement part) for housing the LED 4a as a bullet-type LED. The accommodating portion 5 c ′ extends so as to be inclined with respect to the back surface of the light guide plate 10. Also by the block 5 a ′, the light emitted from the LED 4 a can enter the light guide plate 10 obliquely.

  As shown in FIG. 8C, the optical coupling member 5 is a sheet-like member (for example, a prism sheet) having a triangular prism-shaped body 5d bonded (fixed) to the back surface of the light guide plate 10. May be. In this case, as shown in FIG. 8C, the LED 4a and the optical coupling member 5 are separated from each other, and an air gap is provided. The optical coupling member 5 is bonded to the back surface of the light guide plate 10 so that the triangular prism-shaped body 5a faces the LED 4a. The light emitted from the LED 4 a enters the light guide plate 10 by the triangular prism-shaped body 5 d formed on the optical coupling member 5. Then, the light propagates while totally reflecting in the light guide plate 10. As described above, according to the configuration of FIG. 8C, even if the light source unit 4 </ b> A or 4 </ b> B is disposed on the back side of the light guide plate 10 by the optical coupling member 5, It is possible to increase the amount of propagating component to propagate.

In addition, the triangular prism-shaped body 5d may be a shape used for a known prism sheet or the like, but is preferably a right-angled triangular prism shape whose section is a right triangle rather than a triangular prism shape whose section is an isosceles triangle. Specifically, a triangular prism shaped body 5d of the optical coupling member 5, a third side forming a right triangle, the first surface 5d ₁ parallel to the back surface of the light guide plate 10, the perpendicular to the rear surface of the light guide plate 10 2 surface 5d ₂ and a third surface 5d ₃ as an inclined surface. The third surface 5d ₃ of a surface inclined to the propagation direction from the second surface 5d _2. By making the triangular prism-shaped body 5d into the right triangular prism shape as described above, the amount of light propagating in the propagation direction in the light guide plate 10 can be increased. As a result, the directivity of the light emitted from the LED 4a in the propagation direction of the light guide plate 10 can be enhanced. Further, a curved shape body may be used instead of the triangular prism shape body. The shape of the optical coupling member can be appropriately selected according to the conditions of the light source and the propagation inside the light guide plate 10. Here, the propagation direction means a direction from the first edge where the light source unit 4A is provided toward the second edge where the light source unit 4B is provided.

  8A to 8C is a configuration in which the light emitted from the LED 4a is incident on the light guide plate 10 through the optical coupling member 5. However, the coordinate input device 3A is not limited to this configuration, and may be a configuration in which, for example, the optical coupling member 5 and the light guide plate 10 are integrated by welding or the like. The coordinate input device 3A may have a configuration in which the light coupling member 5 is omitted by welding and fixing the light source unit 4A and the light guide plate 10.

Here, the setting of the propagation angle θ _p of the light propagating through the light guide plate 10 contributing to the detection of the position of the finger 8 was verified. In this verification, a light guide plate having a 45 ° inclined surface with one end surface inclined at 45 ° was used. Then, a laser beam (parallel light) having a Lambert distribution is incident from a 45 ° inclined surface to propagate the light into the light guide plate. Then, the amount of change in the amount of light due to the scattered light caused by the finger contact with the light guide plate is measured by a power meter provided on the other end surface opposite to the 45 ° inclined surface. The amount of change in the amount of light due to scattered light generated by finger contact of the light guide plate with respect to each incident angle was measured by changing the incident angle with respect to the 45 ° inclined surface. In this verification, an acrylic light guide plate having a thickness of 1 mm or 2 mm and a length of 330 mm was used as the light guide plate. Figure 9 shows the result of the verification is a graph showing the relationship between amount of light caused by the finger contact of the light guide plate and the propagation angle theta _p. The vertical axis of the graph in FIG. 9 indicates the amount of change by the power meter.

As shown in FIG. 9, when the propagation angle theta _p is 25 ° or more, it can be seen that the light intensity variation due to scattered light produced by the finger contact is increased. Given the critical angle of the acrylic light guide plate is 48 °, among the light propagating in the light guide plate, light angular component propagation angle theta _p is less than 25 ° or 48 ° is, the position detection of the finger It turns out that it contributes greatly. This tendency was observed both when the thickness of the acrylic light guide plate was 1 mm and when the thickness of the acrylic light guide plate was 2 mm.

  From the results shown in FIG. 9, when a light source (LED) that emits a laser beam having a Lambert distribution is used, the intensity peak is 36 to 37 ° with respect to a 45 ° inclined surface in order to improve finger position detection. It can be seen that the incident angle should be set as described above.

  The refractive index of the block 5 a or 5 a ′ as the optical coupling member 5 is preferably larger than or equal to the refractive index of the light guide plate 10. More preferably, the refractive index of the optical coupling member 5 is the same as the refractive index of the light guide plate 10. As a result, it is possible to eliminate the optical loss that occurs at the interface between the block 5a or 5a 'and the light guide plate 10. As a result, the light from the LED 4a can be optically coupled to the light guide plate 10 efficiently.

In consideration of the result of FIG. 9, in the present embodiment, the LED 4 a has the light coupling member 5 so that the propagation angle θ _p with respect to the back surface of the light propagating through the light guide plate 10 is 25 ° or more and less than 48 °. (Block 5a or 5a ′) may be installed. The angle θ ₁ formed by the optical axis of the light emitted from the LED 4a and the normal line of the back surface of the light guide plate 10 is appropriately determined according to the refractive index of the block 5a or 5a ′, the refractive index of the light guide plate 10, the radiation angle of the LED 4a, etc. , the propagation angle theta _p for the back surface of the light propagating through the light guide plate 10 can be designed to be less than 48 ° 25 ° or more. Considering the materials of LED4a type and the light guide plate 10 used in the art, the angle theta _1, preferably 45 ° ± 10 ° (35 ° or 55 ° or less), more preferably 45 ° ± 5 ° ( 40 ° to 50 °).

When the refractive index of the block 5a or 5a ′ is larger than the refractive index of the light guide plate 10, the optical axis of the light propagating through the light guide plate 10 according to Snell's law even if the angle θ ₁ is set relatively large. the angle theta ₂ between the back side of the normal line of the light guide plate 10 is smaller than the angle theta _1. For this reason, even if the angle θ ₁ is set relatively large, the propagation angle θ _p can be increased. As a result, the easily propagation angle theta _p can be less than 48 ° 25 ° or more.

  Further, when the block 5a or 5a ′ as the optical coupling member 5 is disposed in the effective visual field region of the imaging units 20, 30, 40, and 50, the scattered light component from the finger that guides the light toward the imaging unit. May be blocked by the block 5a or 5a ′. This phenomenon occurs, for example, when the finger 8 touches the edge portion of the liquid crystal display panel 2a (display area).

  Therefore, as illustrated in FIG. 10, the block 5 a or 5 a ′ as the optical coupling member 5 is disposed behind the effective field area of the imaging unit 40. In other words, the block 5 a or 5 a ′ as the optical coupling member 5 is arranged avoiding the effective visual field region of the imaging unit 40. Thereby, it is possible to prevent the scattered light component from the finger guided to the imaging unit from being blocked by the block 5a or 5a '.

(Coordinate detection principle of coordinate input device)
With respect to the coordinate detection principle when the finger 8 is brought into contact with the light guide plate 10 in the coordinate input device 3A having the above-described configuration, FIG. 5, FIG. 7, FIG. 11 (a) (b) and FIG. 12 (a) (b) Based on FIG. 11A is a plan view showing the detection principle of the coordinate input device 3A, and FIG. 11B is a waveform diagram showing the optical signal of the image sensor in the imaging unit of the coordinate input device 3A. FIG. 12A is a plan view showing a contact position when a finger is brought into contact with various places on the surface of the light guide plate, and FIG. 12B shows a detection image of the image sensor corresponding to the contact position of the finger. It is a wave form diagram which shows the relationship between the pixel number which appears and signal strength.

  First, in the coordinate input device 3A, as shown in FIG. 5, light is obliquely incident on the light guide plate 10 from the plurality of LEDs 4a of the light source unit 4A provided along at least one edge of the light guide plate 10. The

  As shown in FIG. 5, the light incident on the light guide plate 10 is guided as propagating light to the entire inner surface of the light guide plate 10. That is, light repeats total reflection inside the light guide plate 10 due to the difference between the refractive index of the light guide plate 10 and the refractive index of air. The totally reflected light is emitted from the end face of the light guide plate 10. The light that is reflected by the end face of the light guide plate 10 and returned is absorbed by the light absorbing members 7 and 7 on the front and back surfaces of the light guide plate 10 and does not return to the imaging units 20 and 30 side.

Here, as shown in FIG. 5, when the finger 8 is brought into contact with, or touched with, the surface of the light guide plate 10, the total reflection condition in the light guide plate 10 is broken, and the finger 8 passes through the light guide plate 10 having the refractive index n. Part of the infrared light that is guided is scattered. Of this scattered light, the propagation angle θ _P in the light guide plate 10 is
sin (90 ° −θ _P )> 1 / n
The light beam satisfying the conditions shown in (2) repeats reflection 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. 7, infrared light that is scattered light of the finger 8 is diffused radially with respect to the two-dimensional plane of the light guide plate 10 and propagates in the light guide plate 10. A part of the propagation light 13a / 14a of the luminous flux is also guided to the wall surfaces 11a / 11a of the conical through holes 11/11, and the reflected light of the wall surfaces 11a / 11a is captured by the imaging units 20/30. The light is received at. Specifically, 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 in the imaging units 20 and 30, and then passes through the optical filters 22 and 32, and finally. Light is received by the image sensors 23 and 33. As a result, as shown in FIG. 11B, a light emission peak appears at the pixel number in each of the image sensors 23 and 33. Therefore, the detection unit 6 converts the pixel number in each image obtained from each of the image pickup devices 23 and 33 into an angle, so that the light guide plate 10 at the location where the finger 8 is in contact as shown in FIG. Angles α and β, which are viewing angles from the imaging units 20 and 30 in the two-dimensional plane, are obtained.

For example, as shown in FIG. 12A, when the finger 8 is in contact with each of the points P ₁ to P ₉ on the light guide plate 10, the image sensor 43 of the image pickup unit 40 has the image sensor 43 shown in FIG. As shown, each peak appears at the position of the pixel number corresponding to the points P ₁ to P ₉ . By converting this pixel number into an angle, the angles of the points P ₁ to P ₉ can be obtained. In FIG. 12B, it can be roughly seen that pixel number 100≈angle 80 degrees, pixel number 200≈angle 60 degrees, pixel number 300≈angle 40 degrees, pixel number 400≈angle 20 degrees.

(Calculation method of 2D coordinate position)
Next, a method for calculating the two-dimensional coordinate position of the light guide plate 10 at the place where the finger 8 is in contact will be described with reference to FIGS. This processing is performed by the detection unit 6. Here, FIG. 13A is a perspective view showing an imaging state in the imaging unit 20 in the coordinate input device 3A, and FIG. 13B is a plan view showing an image in the imaging element 23 of the imaging unit 20. . Although only the imaging unit 20 will be described in FIGS. 13A and 13B, the same processing is performed in the imaging unit 30.

  As shown in FIGS. 5 and 13A, the light incident on the imaging unit 20 passes through the lens 21 and forms a linear image 25 on the imaging element 23. The position of the linear image 25 varies depending on the position of the finger 8, and the angle α formed between the propagation light 13 a and one side of the light guide plate 10 is obtained by analyzing the acquired image of the image sensor 23. Similarly, a linear image 25 is formed on the image pickup device 33 through the lens 31 by the light incident on the image pickup unit 30. Then, by analyzing the acquired image of the image sensor 33, an angle β formed by the propagation light 14a and one side of the light guide plate 10 is obtained. Based on the angles α and β, the position coordinates of the point touched by the finger 8 are obtained using triangulation.

Specifically, in FIG. 13 (a), the time the finger 8 is in the position of point P _1, as shown in FIG. 13 (b), the linear image 25 is formed. Also, the fingers 8 when moved to the position of the point P _2, the image 27 of the line shape is formed.

  When the light from the light source unit 4A is irradiated, when the finger 8 is not in contact with the light guide plate 10, no change occurs in the acquired images of the image sensors 23 and 33. On the other hand, when the finger 8 comes into contact with the light guide plate 10 and scattered light is generated, the propagation lights 13a and 14a in a part of the light flux are guided to the imaging elements 23 and 33, and are applied to the imaging surfaces of the imaging elements 23 and 33. A linear image is formed, and a linear image 25 appears on the acquired image.

The position of the linear image 25 shown in FIG. 13B changes depending on the position of the contact point on the finger 8, and when the position of the contact point on the finger 8 is changed, the linear image 25 becomes linear. It changes like an 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 circular arc as the rotation center) is the line segment connecting the finger 8 and the image pickup device 23 and the light guide plate 10 described above. 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 finger 8 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 finger 8 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 finger 8 touches can be 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 in the coordinate input device 3A 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.

  Further, based on the position coordinates of the finger 8 obtained by the above method, the pixel at the position corresponding to the position coordinates of the liquid crystal display panel 2a is driven, and the user visually recognizes the touch position of the finger 8. Is possible. For this purpose, a control unit (not shown) that controls the driving of the liquid crystal display panel 2a may acquire information on the position coordinates obtained by the detection unit 6 and drive the liquid crystal display panel 2a based on the information.

(Coordinate detection method for contact position on multiple fingers)
In the coordinate input device 3A of the present embodiment, even when a plurality of fingers 8 are in contact with the light guide plate 10, the coordinate position of each finger 8 can be detected without hindrance. A configuration for this will be described with reference to FIG. FIG. 1 is an explanatory diagram showing a configuration for enabling detection even when a plurality of fingers 8 touch the light guide plate 10 in the coordinate input device 3A of the present embodiment.

  As described above, the coordinate input device 3A of the present embodiment includes the plate-shaped light guide plate 10, the light source units 4A and 4B that allow light to enter the light guide plate 10, and at least two imaging units 20, 30, 40, and so on. 50 and the light guide plate in the finger 8 based on the output of the imaging units 20, 30, 40, and 50 that detect light scattering by the finger 8 when the detected object such as the finger 8 contacts the surface of the light guide plate 10. And a detection unit 6 that detects the coordinates of the position of contact with the surface of 10.

  In such a coordinate input device 3A, the light reception peak of the scattered light due to the presence of the detection object such as the finger 8 is detected in a state where the light reception change amount of the imaging units 20, 30, 40, and 50 is maintained at zero.

  In the coordinate input device 3A of the present embodiment, the imaging units 20 and 30 and the light source unit 4A are provided at the first edge along the longitudinal direction of the light guide plate 10, and the imaging units 40 and 50 and the light source unit 4B are It is provided on each of the second edges facing the first edge along the longitudinal direction.

  By the way, when it is set as such a structure, when the light source unit 4A of the 1st edge part and the light source unit 4B of the 2nd edge part facing this 1st edge part are lighted simultaneously, an imaging unit Since the light from the light source units 4A and 4B facing each other is incident on the 20 and 30 or the imaging units 40 and 50, the scattered light due to the contact of the finger 8 cannot be detected.

  Therefore, in the present embodiment, as shown in FIG. 1, the light source unit 4A at the first edge and the light source unit 4B at the second edge are lit alternately. That is, the light source unit 4B is turned off while the light source unit 4A is turned on, and the light source unit 4A is turned off while the light source unit 4B is turned on. The blinking speed is alternately turned on at 60 Hz, for example. However, the present invention is not necessarily limited to this, and the blinking speed can be set to 240 Hz, for example, and can be slower than 60 Hz.

  And in the period when the light source unit 4B of the 1st edge part in the light-guide plate 10 is lighting, the contact to the surface of the light-guide plate 10 in the finger | toe 8 in the imaging unit 20 * 30 provided in this 1st edge part Detect position coordinates. On the other hand, in the period when the light source unit 4B at the second edge of the light guide plate 10 is lit, the imaging unit 40, 50 provided at the second edge contacts the surface of the light guide plate 10 with the finger 8. Detect position coordinates.

  As a result, the light from the light source unit 4B facing the imaging units 20 and 30 is prevented from entering, and the light from the light source unit 4A is prevented from entering the imaging units 40 and 50. For this reason, the scattered light by contact of the finger | toe 8 is detectable.

  As a result, for example, when the finger 8A as the first detected body and the finger 8B as the second detected body are simultaneously in contact with the light guide plate 10, the detection signals of the imaging units 20, 30, 40, and 50 are detected. Can be separated and detected. Strictly speaking, since the signal detection of the imaging units 40 and 50 at the second edge that is the upper side and the signal detection of the imaging units 20 and 30 at the first edge that is the lower side are alternated, they are not simultaneous. However, by shortening the blinking cycle or applying signal processing that interpolates movement from the preceding and following data, it is possible to handle the same as in the case of simultaneous detection. Further, if the interpolation data is used only for removing the erroneous recognition point, it is possible to suppress the deviation from the actual contact point.

  For example, the imaging units 20 and 30 detect both the finger 8A that touches first and the finger 8A that touches later. However, by removing the data of the finger 8 detected by the previous lighting of the light source unit 4A, the finger 8A due to the subsequent lighting of the light source unit 4A can be detected. Therefore, the coordinates of the contact position of each finger 8 can be obtained even when three or more fingers 8 are in contact with the light guide plate 10.

  Further, as will be described later in Embodiment 2, it is possible to simultaneously detect three or more fingers 8 by increasing the number of light receiving means.

  As described above, in the coordinate input device 3A of the present embodiment, the imaging units 20 and 30 and the light source unit 4A are provided on one first edge along the longitudinal direction of the light guide plate 10, and the imaging units 40 and 50 are provided. And the light source unit 4B is provided in the other 2nd edge part which opposes the 1st edge part along a longitudinal direction, respectively.

  Moreover, the coordinate detection method of this Embodiment is a coordinate detection method using the coordinate input device 3A of this Embodiment, Comprising: The period when the light source unit 4A of the 1st edge part in the light-guide plate 10 is lighting. The coordinates of the contact position of the finger 8A on the surface of the light guide plate 10 are detected by the imaging units 20 and 30 provided at the first edge portion, while the light source unit 4B at the second edge portion of the light guide plate 10 is detected. The coordinates of the contact position of the finger 8 on the surface of the light guide plate 10 are detected by the imaging units 40 and 50 provided at the second edge during the period when is lit.

  Thereby, in the optical coordinate input device 3A using the light guide plate 10, the coordinate input device 3A and the coordinate detection method capable of detecting the coordinate positions of the plurality of fingers 8 can be provided.

  In the coordinate input device 3A of the present embodiment, the planar light guide plate 10 has a rectangular planar shape, and the imaging units 20, 30, 40, and 50 and the light source units 4A and 4B have a light guide plate. 10 at the edge of the long side.

  That is, in the present embodiment, when a detection target such as the finger 8 is brought into contact with the light guide plate 10, the scattered light is detected by the imaging units 20, 30, 40, and 50. For this reason, the greater the amount of scattered light, the greater the detection intensity of the imaging units 20, 30, 40, 50, and the easier it is to detect. For that purpose, it is necessary to increase the light amount density of the irradiation region to the light guide plate 10 material in the light source units 4A and 4B.

  Therefore, in the present embodiment, since the light guide plate 10 has a rectangular planar shape, the imaging units 20, 30, 40, and 50 and the light source units 4A and 4B are connected to the long side edge of the light guide plate 10. Provided. Thereby, since the distance from the light source units 4A and 4B to the opposite end portion of the light guide plate 10 is reduced, the light amount density of the irradiation region to the light guide plate 10 in the light source units 4A and 4B can be increased.

  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 module 2.

  According to this configuration, the coordinate input device 3 </ b> A can be made to function as a touch panel that inputs with a detected object such as the finger 8 while viewing the image of the liquid crystal display module 2. Therefore, in the optical coordinate input device 3A using the light guide plate 10, even when applied to a large touch panel, the coordinate input system provided with the coordinate input device 3A that can detect the coordinate position of the detected object such as the finger 8 or the like. 1 can be provided.

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

  In the coordinate input device 3A of the first embodiment, the imaging units 20 and 30 and the light source unit 4A are provided at the first edge along the longitudinal direction of the light guide plate 10, and the imaging units 40 and 50 and the light source unit 4B are , And the second edge facing the first edge along the longitudinal direction.

  On the other hand, in the coordinate input device 3B of the present embodiment, three or more light receiving means are provided at the first edge portion along the longitudinal direction of the light guide plate 10 and the longitudinal length of the light guide plate 10 is longer. The difference lies in that three or more light receiving means are also provided on the second edge facing the first edge along the direction.

  The configuration of the coordinate input device 3B according to the present embodiment will be described with reference to FIGS. FIG. 14 is a plan view showing a state in which the finger is in contact with the proximity position of the imaging unit in the coordinate input device 3A of the first embodiment. FIG. 15 is a plan view showing a defect when a finger is simultaneously brought into contact with two places in the coordinate input device 3A of the first embodiment. FIG. 16 is a perspective view showing the configuration of the coordinate input device 3B in the present embodiment. FIG. 17 is a plan view showing a lighting control method for the light source units 4A and 4B of the coordinate input device 3B. FIG. 18 is a plan view showing a detection method when the finger is brought into contact with the proximity position of the imaging unit in the coordinate input device 3B. FIG. 19 is a plan view showing a detection method when a plurality of fingers are in contact with the light guide plate in the coordinate input device 3B.

  That is, when the two imaging units 20 and 30 are provided as the light receiving means at the first edge along the longitudinal direction of the light guide plate 10, detection may be hindered as follows.

For example, as shown in FIG. 14, the light guide plate 10, it is possible to easily detect the coordinates of the contact position P ₁ of the finger 8 away from the imaging unit 20, 30. However, as shown in FIG. 14, the light guide plate 10, for the coordinate contact position P ₂ of the finger 8 in proximity to the imaging unit 20, 30, the angle of the viewing direction from the imaging unit 20, 30 is small The angle change with respect to the position change is small. As a result, there is a problem that detection accuracy is deteriorated.

Further, as shown in FIG. 15, for example, if two fingers 8A-8B are contacted simultaneously to the point _{P 1} and point _{P 2} on the surface of the light guide plate 10, the imaging unit 20, 30, two fingers 8A- There is a possibility that 8B is erroneously recognized as existing at the points P ₃ and P ₄ .

  Therefore, in the coordinate input device 3B of the present embodiment, as shown in FIG. 16, six imaging units 20, 30, 40, 50, 60, and 70 are provided as light receiving means. Specifically, three imaging units 20, 60, and 30 are provided on one first edge portion along the longitudinal direction of the light guide plate 10, and the first edge along the longitudinal direction of the light guide plate 10 is provided. Three imaging units 40, 70, and 50 are provided on the second edge facing the part.

  In this case, the light source units 4A and 4B are not arranged at the locations where the central imaging units 60 and 70 are arranged. Thereby, it can prevent that the light of LED4a injects into the center imaging unit 60 * 70.

  Also in the coordinate input device 3B of the present embodiment, as shown in FIG. 17, the light source unit 4A at the first edge and the light source unit 4B at the second edge are alternately turned on.

Thus, as shown in FIG. 18, the coordinate contact position P ₂ of the finger 8 in proximity to the imaging unit 20, 30, even when the angle β in the viewing direction from the imaging unit 30 is small, the center of By using the imaging unit 70, an angle β ′ in the viewing direction from the imaging unit 70 that is larger than the angle β in the viewing direction from the imaging unit 30 can be obtained.

  Thereby, the problem that the detection accuracy of the contact position of the finger 8 close to the imaging units 20 and 30 is deteriorated can be solved.

Further, as shown in FIG. 19, the case where two fingers 8A · 8B on the surface of the light guide plate 10 is contacted simultaneously at the point P ₁ and point P _2, the two fingers 8A · 8B by using the imaging unit 60 obtaining the viewing angle to the point _{P 1} and point _{P 2.} As a result, when using the imaging unit 20 and the imaging unit 60, apart from the points P ₁ and the point P _2, a possibility that two fingers 8A · 8B is provided and the point P ₅ and the point P ₆ is detected Is done. In this case, the points P ₁ and P ₂ obtained by the imaging units 20 and 30 shown in FIG. 15 coincide with the points P ₁ and P ₂ obtained by the imaging units 20 and 60 shown in FIG. As a result, by using the three imaging units 20, 30, 60 for the two fingers 8 A, 8 B, the points P ₁ and P ₂ that are the contact positions of the two fingers 8 A, 8 B on the light guide plate 10 are obtained. Can be obtained accurately. In this method, generally, if N + 1 light receiving means exist for simultaneous contact of N (N is an integer of 2 or more) points on the light guide plate 10, N (N is an integer of 2 or more). ) It is possible to accurately detect simultaneous contact of points. In addition, as in the present embodiment, the light source units 4A and 4B are alternately controlled to blink using the six imaging units 20, 30, 40, 50, 60, and 70, so that the five points of the finger 8 can be simultaneously controlled. Detection is possible.

  As described above, in the coordinate input device 3B according to the present embodiment, the first and second edges of the light guide plate 10 each have at least three imaging units 20, 60, and 30 as light receiving means. In addition, imaging units 40, 70 and 50 are provided.

  As a result, even when the finger 8 is present at any location on the light guide plate 10, it is possible to prevent the contact position detection accuracy from being lowered. Further, the contact position of each finger 8 can be accurately detected even in simultaneous contact of a plurality of fingers 8.

  In the coordinate input device 3B of the present embodiment, at least two light source units 4A and 4A and light source units 4B and 4B are provided on the first edge and the second edge of the light guide plate 10, respectively. Preferably it is. Thereby, in order to obtain sufficient detection intensity in each of the three or more imaging units 20, 60, and 30 and the imaging units 40, 70, and 50, by increasing the light source units 4A and 4A and the light source units 4B and 4B, It is possible to increase the detection accuracy.

  In the coordinate input device 3A of the present embodiment, the imaging units 20 and 30 and the light source unit 4A are provided at one first edge portion along the longitudinal direction of the light guide plate 10, and the imaging units 40 and 50 and the light source The unit 4B is provided on each of the other second edges facing the first edge along the longitudinal direction.

  Moreover, the coordinate detection method of this Embodiment is a coordinate detection method using the coordinate input device 3B of this Embodiment, Comprising: The period when the light source unit 4A of the 1st edge part in the light-guide plate 10 is lighting. The coordinates of the contact position of the finger 8A on the surface of the light guide plate 10 are detected by the imaging units 20, 30 and 60 provided on the first edge portion, while the light source of the second edge portion of the light guide plate 10 is detected. During the period when the unit 4B is lit, the coordinates of the contact position of the finger 8 on the surface of the light guide plate 10 are detected by the imaging units 40, 50 and 70 provided at the second edge.

  Thereby, in the optical coordinate input device 3B using the light guide plate 10, the coordinate input device 3B and the coordinate detection method capable of detecting the coordinate positions of the plurality of fingers 8 can be provided.

  In the coordinate input device 3A of the present embodiment, the planar light guide plate 10 has a rectangular planar shape, and the imaging units 20, 30, 60, 40, 50, 70 and the light source units 4A, 4B. Is provided at the edge of the light guide plate 10 on the long side.

  That is, in the present embodiment, when a detection target such as the finger 8 is brought into contact with the light guide plate 10, the scattered light is detected by the imaging units 20, 30, 60, 40, 50, and 70. For this reason, the detection intensity in the imaging units 20, 30, 60, 40, 50, and 70 increases as the amount of scattered light increases, and the detection becomes easier. For that purpose, it is necessary to increase the light amount density of the irradiation region to the light guide plate 10 material in the light source units 4A and 4B.

  Therefore, in this embodiment, since the light guide plate 10 has a rectangular planar shape, the imaging units 20, 30, 60, 40, 50, 70 and the light source units 4A, 4B are connected to the long side of the light guide plate 10. It is provided on the side edge. Thereby, since the distance from the light source units 4A and 4B to the opposite end portion of the light guide plate 10 is reduced, the light amount density of the irradiation region to the light guide plate 10 in the light source units 4A and 4B can be increased.

  The coordinate input system 1 according to the present embodiment is a coordinate input system including the coordinate input device 3B according to the present embodiment, and includes a liquid crystal display module 2.

  According to this configuration, the coordinate input device 3 </ b> B can function as a touch panel that inputs with a detection object such as the finger 8 while viewing the image of the liquid crystal display module 2. Therefore, in the optical coordinate input device 3B that uses the light guide plate 10, even when applied to a large touch panel, the coordinate input system including the coordinate input device 3B that can detect the coordinate position of the detection target such as the finger 8 or the like. 1 can be provided.

  The coordinate input device described above is configured to detect a light reception peak of scattered light caused by contact of the detected body with the surface of the light guide member when the light source is turned on. However, the coordinate input device of the present invention is not limited to the above-described configuration, and is based on a light scattering phenomenon caused by contact of the detected body with the surface of the light guide member in a state where a certain amount of received light is given to the light receiving means. In this case, a decrease in output intensity in the light receiving means may be detected.

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

  The present invention includes a plate-shaped light guide member, a light source that makes light incident on the light guide member, a light receiving unit, and light scattering by the detected object when the detected object contacts the surface of the light guide member. The present invention is applied to a coordinate input device, a coordinate detection method, and a coordinate input system that include detection means for detecting the coordinates of the contact position of the detected body with respect to the surface of the light guide member based on the detected output of the light receiving means. be able to. Further, the coordinate input device can be applied to both a finger type and a touch pen type. Furthermore, the coordinate input system can be applied to a personal computer, a television, a white board, a tablet terminal, and the like.

1 Coordinate input system 2 Liquid crystal display module (image display module)
2a Liquid crystal display panel 3A Coordinate input device 3B Coordinate input device 4A Light source unit (light source)
4B Light source unit (light source)
4a LED
5 Optical coupling member 5a, 5a 'Block 5c Inclined surface (light source arrangement part)
5c 'storage part (light source arrangement part)
6 Detection part (detection means)
7 Light Absorbing Member 8 Finger (Detected Object)
8A finger (first detected object)
8B finger (second object to be detected)
10 Light guide plate (light guide member)
11 Through-hole 11a Wall surface 13a Propagating light 20 Imaging unit (light receiving means)
21 Lens 22 Optical filter 23 Imaging device 30 Imaging unit (light receiving means)
31 Lens 32 Optical filter 33 Imaging device 40 Imaging unit (light receiving means)
50 Imaging unit (light receiving means)
60 Imaging unit (light receiving means)
70 Imaging unit (light receiving means)
L interval

Claims (6)

A plate-shaped light guide member, a light source for making light incident on the light guide member, at least two light receiving means, and detecting light propagating in the light guide member when the object to be detected contacts the surface of the light guide member A coordinate input device including detection means for detecting coordinates of a contact position of the detected body with the surface of the light guide member based on the output of the light receiving means,
A coordinate input device comprising an optical coupling member that couples light emitted from a light source so as to be incident obliquely with respect to the back surface of the light guide member.   The optical coupling member includes a contact surface that is in contact with the light guide member, and a light source arrangement portion for arranging the light source so that an optical axis direction of emitted light of the light source is inclined with respect to a back surface of the light guide member. 2. The coordinate input device according to claim 1, wherein the light of the light source is incident on the light guide member through the contact surface. The said light source is installed in the said optical coupling member so that the propagation angle (theta) _p with respect to the said back surface of the light which propagates the said light guide member may be 25 to 48 degrees. The coordinate input device according to 2.   The coordinate input device according to claim 1, wherein a refractive index of the optical coupling member is the same as a refractive index of the light guide member.   The light source is disposed on the optical coupling member so that an angle formed by an optical axis of the emitted light and a normal line on the back surface of the light guide member is 45 ± 10 °. The coordinate input device of any one of -4. A coordinate input system comprising the coordinate input device according to claim 1,
A coordinate input system comprising an image display module.

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