JP2014002476A - Coordinate input device and coordinate input system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coordinate input device that can obtain good signal quality and enables stable signal detection without deformation of a light guide plate even when an environment is changed.SOLUTION: A coordinate input device 3A includes: a device body including a tabular light guide member 10, light sources for making light incident on the light guide member, at least two light-receiving means, and detection means for detecting coordinates of a position of a touch to the surface of the light guide member by a body to be detected on the basis of output from the light-receiving means having detected light propagated into the light guide member when the body to be detected touches the surface of the light guide member; and a frame member 9 provided at an edge portion of the light guide member in the device body. The device body is provided with a relaxation member 14 that relaxes stress produced on the frame member by expansion and contraction of the light guide member and that changes relative positions of the device body and the frame member.

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. 21A and 21B, 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, and 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.

  Moreover, in 3rd Embodiment of patent document 1, as shown to Fig.23 (a) (b), the light source 102a, the light receiving element 104a, the light source 102b, and the light receiving element 104b are respectively set to the opposing end surface 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. 16, there are a plurality of possible combinations of contact positions on the detection object 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)

  By the way, the touch panel provided with the coordinate input device generally includes a frame member that holds at least the edge portion of the light guide plate with the coordinate input device as the device main body. However, in the technique of the above-mentioned Patent Document 1, no consideration is given to this frame member.

  Here, when a member having a different linear expansion coefficient, such as a light guide plate or a frame member, is fastened with a screw or bonded with an adhesive, an environmental change (for example, a change to a high temperature environment or a change to a low temperature environment) ), Each member expands and contracts due to a difference in linear expansion coefficient. As a result, the light guide plate may be deformed and the signal quality may be degraded.

  The present invention has been made in view of the above problems, and its purpose is to obtain a good signal quality and stable signal detection even when the environment changes, the light guide plate is not deformed. An object is to provide a coordinate input device and a coordinate input system.

  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 position of the light guide member in contact with the surface of the light guide member based on the output of the light receiving means that has detected the propagation light in the light guide member when contacting the target object; A coordinate input device comprising an apparatus main body and a frame member provided at an edge of the light guide member in the apparatus main body, wherein stress generated in the frame member by expansion and contraction of the light guide member And a relaxation member that changes the relative position between the apparatus main body and the frame member is provided.

  According to the above configuration, the apparatus main body is provided with a relaxation member that relieves stress generated in the frame member due to expansion and contraction of the light guide member and changes a relative position between the apparatus main body and the frame member. Even when an environmental change (for example, a change to a high temperature environment or a change to a low temperature environment) occurs and the light guide member expands or contracts, the stress generated in the frame member is reduced by the relaxation member. And since the relative position of an apparatus main body and a frame member changes by this, a light guide member does not deform | transform. Therefore, according to the above configuration, even when the environment changes, the light guide member is not deformed, and a coordinate input device capable of obtaining a good signal quality and stable signal detection is realized. can do.

  In the coordinate input device according to the present invention, the coordinate input device is provided on the back side of the device main body and includes at least a housing for supporting the device main body, and the frame member is held by the relaxation member on the housing. Is preferred. The relaxation member relieves stress caused by a difference in linear expansion coefficient between the frame member and the holding member.

  According to the above configuration, since the frame member and the housing are held by the relaxation member, the frame member and the housing are relative to each other even when an environmental change occurs. The positional relationship changes. Therefore, the difference in expansion and contraction that occurs between the frame member and the housing is reduced. Therefore, according to the above configuration, even when the environment changes, the light guide member is not deformed, and good signal quality is obtained and stable signal detection is possible.

  The relaxation member may be a double-sided tape.

  In this case, the stress caused by the difference in expansion and contraction caused by the difference in linear expansion coefficient between the holding member and the frame member is alleviated by deformation of the double-sided tape as the relaxing member. As a result, according to said structure, the stress which generate | occur | produces with a frame member can be reduced.

  In the coordinate input device according to the present invention, the casing and the frame member are each formed with first and second openings that communicate with each other, and the relaxation member includes the first and second openings. The rivet is inserted into both of the first and second openings, and one of the first and second openings is used to lock the rivet. The dimension may be smaller than the other opening.

  According to said structure, the said relaxation member is a rivet inserted in both the said 1st and 2nd opening part, and latched by either one of the said 1st and 2nd opening part. Since one opening for locking the rivet has a smaller size than the other opening, the first and second rivets are inserted in the first and second openings. A clearance is formed between the other opening of the two openings that does not lock the rivet and the rivet. Even when an environmental change occurs due to this clearance, the relative positional relationship between the frame member and the housing changes. Therefore, the difference in expansion and contraction that occurs between the frame member and the housing is reduced. Therefore, according to the above configuration, even when the environment changes, the light guide member is not deformed, and good signal quality is obtained and stable signal detection is possible.

  In the coordinate input device of the present invention, it is preferable that the light guide member is held on the frame member by the relaxation member. The relaxation member relieves stress caused by a difference in linear expansion coefficient between the frame member and the light guide member.

  Thereby, even when the environmental change occurs, the relative positional relationship between the frame member and the light guide member changes. Therefore, according to the above configuration, even when the environment changes, the light guide member is not deformed, and good signal quality is obtained and stable signal detection is possible.

  In the coordinate input device of the present invention, it is preferable that the relaxation member is a double-sided tape and is provided on both the front surface and the back surface of the light guide member.

  In this case, the stress resulting from the difference in expansion and contraction caused by the difference in linear expansion coefficient between the light guide member and the frame member is alleviated by deformation of the double-sided tape as the relaxation member. As a result, according to said structure, the stress which generate | occur | produces with a frame member can be reduced.

  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.

  When the coordinate input system of the present invention includes a plate-like holding member that is disposed on the back side of the apparatus main body and holds the frame member, the coordinate input system includes an image display module, and the housing includes the image It is preferable that the display module and the apparatus main body are configured to be supported.

  According to the above configuration, it is possible to realize a coordinate input system in which a light guide member is not deformed even when an environmental change occurs, a good signal quality is obtained, and stable signal detection is possible. it can.

  As described above, in the coordinate input device of the present invention, the apparatus body has a relaxation member that relieves stress generated in the frame member due to expansion and contraction of the light guide member and changes a relative position between the apparatus body and the frame member. It is the structure provided.

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

  Therefore, even when the environment changes, the light guide member is not deformed, and it is possible to obtain a good signal quality and to enable stable signal detection.

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. 9 illustrates a configuration of a coordinate input system, and is a cross-sectional view taken along line AA in FIG. 8. It is a top view which shows the irradiation area | region to the light-guide plate in one LED. (A) (b) is sectional drawing which shows the structure of the optical coupling member provided between the light-guide plate and LED. It is a perspective view which shows the optical path of scattered light when a finger touches a light-guide plate. It is sectional drawing which shows the structure of the coordinate input device provided with the frame member and the housing | casing. The other example of the fixing member which fixes a housing | casing and a frame holding member is shown, (a) is sectional drawing, (b) is a top view. It is sectional drawing which shows schematic structure of the modification of the coordinate input device shown in FIG. (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.

[Embodiment 1]
An 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 of the present embodiment includes a liquid crystal display module 2 as an image display module, and a coordinate input device (device main body) 3A provided on the front side of the liquid crystal display module 2. It has.

  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. 7A and 7B are cross-sectional views showing the configuration of the optical coupling member provided between the light guide plate 10 and the LED 4a. FIG. 8 is a perspective view showing an optical path of scattered light when the finger 8 touches the light guide plate 10.

  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 at the outer peripheral end of the light guide plate 10 as compared with the imaging unit 20, and the light source unit 4 </ b> B is guided as compared with the imaging unit 40. It is provided at the outer peripheral end of the optical 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.

  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 of each LED 4a of the light source units 4A and 4B is vertically incident on the light guide plate 10, the incident light does not guide the inside of the light guide plate 10 and remains on the front surface of the light guide plate 10 as it is. Go through. Therefore, in this 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. 7 (a) and 7 (b). In addition, the light from the LEDs 4a of the light source units 4A and 4B is incident on the light guide plate 10 through the optical coupling members 5 and 5 at an angle.

  Specifically, as shown in FIG. 7A, the optical coupling member 5 may be composed of, for example, a triangular prism 5a. The prism 5a can be bonded to the light guide plate 10 using, for example, a double-sided tape 5b or an adhesive. Then, by adhering the LED 4a to the inclined surface of the prism 5a, light can be incident obliquely on the light guide plate 10 as shown in FIG.

  As shown in FIG. 7B, a bullet-type LED 4a can be used as the LED 4a. In this case, as the optical coupling member 5, a transparent block 5 c that can obliquely fix the bullet-type LED 4 a with respect to the light guide plate 10 can be used. This also allows light to enter the light guide plate 10 at an angle.

  Next, as shown in FIG. 8, 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.

(Characteristic configuration of coordinate input device)
By the way, the coordinate input device normally includes a frame member that holds at least the edge of the light guide plate 10 in the coordinate input device 3A with the above-described coordinate input device 3A as the device main body. FIG. 9 is a cross-sectional view showing a configuration of a coordinate input device including such a frame member.

  As shown in FIG. 9, the frame member 9 includes a frame main body 91 and a frame holding member 92 for holding the frame main body 91. The frame main body 91 and the light guide plate 10 are bonded by an adhesive (bonded portion in FIG. 9). Further, the frame main body 91 and the frame holding member 92 are fastened by screws (screw fastening portion in FIG. 9). The frame holding member 92 is supported by the housing 12. The housing 12 is disposed on the rear surface side of the coordinate input device 3A, more specifically, on the rear surface side of the liquid crystal display module 2, and accommodates various members of the liquid crystal display module 2 and various members of the coordinate input device 3A. It is configured to do. It can be said that the housing 12 is a support member that supports at least various members of the coordinate input device 3A from the back side.

  Note that the housing 12 may have a configuration integrated with the liquid crystal display module 2. That is, the coordinate input device 3A includes a configuration including an independent liquid crystal display module 2 and a housing 12, and a frame holding member 92, a composite module in which the liquid crystal display module 2 and the housing 12 are integrated, and a frame holding member. 92. When the coordinate input device 3A has the latter configuration, it is possible to realize a coordinate input device with a narrow frame (the frame width is narrow).

  Here, when members having different linear expansion coefficients such as the light guide plate 10, the frame main body 91, the frame holding member 92, and the housing 12 are fastened with screws or bonded with an adhesive, environmental changes (for example, When a change to a high temperature environment or a change to a low temperature environment occurs, each member expands and contracts due to a difference in linear expansion coefficient. As a result, the light guide plate 10 may be deformed and the signal quality may be deteriorated.

  Therefore, in the coordinate input device 3A, the light guide plate 10 and the frame main body 91 are made of materials having linear expansion coefficients close to each other. The coordinate input device 3 </ b> A is provided with a relaxation member that relieves stress generated in the frame member 9 due to the expansion and contraction of the light guide plate 10.

  Specifically, as shown in FIG. 9, the casing 12 and the frame holding member 92 are fixed by a double-sided adhesive tape 14 that is stretchable and strongly adhesive. The double-sided tape 14 functions as a relaxation member that relieves stress generated in the frame member 9 (specifically, the frame holding member 92) due to expansion and contraction of the light guide plate 10. The double-sided tape is a tape in which a flexible adhesive made of acrylic or the like is applied to both sides of a base material made of paper, cellophane, acrylic foam or the like. In the coordinate input device 3A, a particularly preferable double-sided tape is a tape in which an acrylic adhesive is applied to an acrylic foam base material.

  That is, since the housing 12 and the frame holding member 92 are held by the double-sided tape 14, the housing 12 and the frame holding member 92 are relatively relative to each other even when an environmental change occurs. The positional relationship changes. Therefore, the expansion / contraction difference generated between the housing 12 and the frame holding member 92 is reduced. That is, when the environment changes, the stress caused by the difference in expansion and contraction caused by the difference in linear expansion coefficient between the housing 12 and the frame holding member 92 is relieved by the deformation of the double-sided tape 14.

  The housing 12 and the frame holding member 92 are held together by the adhesive applied to both surfaces of the base material of the double-sided tape 14. For example, when the casing 12 and the frame holding member 92 are bonded by an adhesive, the adhesive has a function of bonding the members by solidifying. The relative position does not change. On the other hand, the base material (for example, acrylic foam base material) to which the adhesive in the double-sided tape 14 is applied can be deformed according to the expansion and contraction of the light guide plate 10 due to environmental changes, unlike the above-described screw fastening or adhesive. The coordinate input device 3A can cope with environmental changes by the deformation of the base material. That is, even if the light guide plate 10 expands and contracts, the relative positions of the frame main body 91 and the frame holding member 92 and the housing 12 change, so that the stress generated in the frame main body 91 and the frame holding member 92 can be reduced. . Therefore, according to the configuration of FIG. 9, even when the environment changes, the light guide plate 10 is not deformed, and good signal quality is obtained and stable signal detection is possible. Note that the amount of deformation of the substrate can be controlled by the outer size, thickness, etc. of the substrate.

  Further, the member (relaxation member) for fixing the housing 12 and the frame holding member 92 is not limited to the above-described “double-sided tape 14”, and the linear expansion coefficient between the frame holding member 92 and the housing 12 is not limited. Any structure may be used as long as the stress due to the difference is relaxed. 10 shows another example of a member (relaxation member) for fixing the housing 12 and the frame holding member 92, FIG. 10 (a) is a cross-sectional view, and FIG. 10 (b) is a plan view. FIG. In FIG. 10B, the push rivet 15 is omitted.

  As shown in FIG. 10A, the housing 12 and the frame holding member 92 are fixed by the push rivet 15. The push rivet 15 is inserted into an opening 12 a (first opening) formed in the housing 12 and an opening 92 a (second opening) formed in the frame holding member 92. The opening 12a and the opening 92a communicate with each other. And the housing | casing 12 and the frame holding member 92 are fixed by the push rivet 15 being latched by one opening part 12a among the opening parts 12a and the opening parts 92a.

  Here, as shown in FIG. 10B, the opening 92 a formed in the frame holding member 92 is larger in size than the opening 12 a formed in the housing 12. That is, of the opening 12a and the opening 92a, one opening 12a that locks the push rivet 15 is smaller in size than the other opening 92a.

  Therefore, in a state where the housing 12 and the frame holding member 92 are fixed, a clearance is formed between the side wall that forms the opening 92 a and the push rivet 15. Even when an environmental change occurs due to this clearance, the relative positional relationship between the casing 12 and the frame holding member 92 changes. That is, when the environment changes, the stress caused by the difference in expansion and contraction caused by the difference in linear expansion coefficient between the housing 12 and the frame holding member 92 is relieved by this clearance. As a result, stress generated in the light guide plate 10, the frame main body 91, and the like can be reduced. Therefore, according to the configuration of FIGS. 10A and 10B, the light guide plate 10 is not deformed even when the environment changes, and a good signal quality is obtained and stable signal detection is possible. It becomes possible.

  The coordinate input device 3A is not limited to the configuration shown in FIGS. 10A and 10B, and the push rivet 15 is locked to one of the opening 12a and the opening 92a. Any configuration may be used. For example, the housing 12 and the frame holding member 92 may be fixed by locking the push rivet 15 to one of the openings 12a and 92a. In this case, of the opening 12a and the opening 92a, one opening 92a that locks the push rivet 15 is smaller in size than the other opening 12a. However, from the viewpoint of securing the fixing strength between the housing 12 and the frame holding member 92, the configuration shown in FIGS. 10A and 10B is particularly preferable.

  In the coordinate input device 3A described above, the member for fixing the housing 12 and the frame holding member 92 functions as a relaxation member that relieves stress generated in the frame member 9 due to expansion and contraction of the light guide plate 10. It was. However, the coordinate input device 3 </ b> A is not limited to this configuration, and may be any configuration provided with a relaxation member that relaxes the stress generated in the frame member 9 due to the expansion and contraction of the light guide plate 10.

  FIG. 11 is a cross-sectional view showing a schematic configuration of a modified example of the coordinate input device 3A. As shown in FIG. 11, the frame member 9 may be configured to be sandwiched from both the front and back surfaces of the light guide plate 10. In this case, the double-sided tape 14 as a relaxation member is provided between the frame member 9 and the light guide plate 10. As described above, the frame member 9 and the light guide plate 10 are held by the stretchable strong adhesive double-sided tape 14, so that the frame member 9 and the light guide plate 10 can be connected to each other even when an environmental change occurs. The relative positional relationship of changes. Therefore, the difference in expansion and contraction that occurs between the frame member 9 and the light guide plate 10 is alleviated. That is, when the environment changes, the stress caused by the difference in expansion and contraction caused by the difference in linear expansion coefficient between the frame member 9 and the light guide plate 10 is relieved by the deformation of the double-sided tape 14. Therefore, according to the configuration of FIG. 11, even when the environment changes, the light guide plate 10 is not deformed, and good signal quality is obtained and stable signal detection is possible. In the configuration shown in FIG. 11, the double-sided tape 14 provided on both the front and back surfaces of the light guide plate 10 can function as a light absorbing member that absorbs light propagating through the light guide plate 10.

(Coordinate detection principle of coordinate input device)
Next, 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 will be described with reference to FIGS. 5, 8, 12A, 12B, and 13A. A description will be given based on (b). FIG. 12A is a plan view showing the detection principle of the coordinate input device 3A, and FIG. 12B is a waveform diagram showing an optical signal of the image sensor in the imaging unit of the coordinate input device 3A. FIG. 13A is a plan view showing a contact position when a finger is in contact with various places on the surface of the light guide plate, and FIG. 13B 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. 8, 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. 12B, 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 illustrated in FIG. 13A, when the finger 8 is in contact with each of the points P ₁ to P ₉ on the light guide plate 10, the imaging element 43 of the imaging unit 40 has the imaging element 43 illustrated 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. 13B, it can be generally 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 location 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. 14A is a perspective view showing an imaging state in the imaging unit 20 in the coordinate input device 3A, and FIG. 14B is a plan view showing an image in the imaging element 23 of the imaging unit 20. . 14 (a) and 14 (b), 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. 5 and 14A, 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. 14 (a), the time the finger 8 is in the position of point P _1, as shown in FIG. 14 (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. 14B 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 (device main body) of the present embodiment, three or more light receiving means are provided on the first edge portion along the longitudinal direction of the light guide plate 10 and the light guide plate 10 is guided. The difference is that three or more light receiving means are also provided on the second edge portion of the optical plate 10 facing the first edge portion along the longitudinal direction.

  The configuration of the coordinate input device 3B according to the present embodiment will be described with reference to FIGS. FIG. 15 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. 16 is a plan view showing a defect when the finger is simultaneously touched at two places in the coordinate input device 3A of the first embodiment. FIG. 17 is a perspective view showing the configuration of the coordinate input device 3B in the present embodiment. FIG. 18 is a plan view showing a lighting control method for the light source units 4A and 4B of the coordinate input device 3B. FIG. 19 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. 20 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. 15, in the light guide plate 10, it is possible to easily detect the coordinate position of the contact position P ₁ of the finger 8 away from the imaging units 20 and 30. However, as shown in FIG. 15, in the light guide plate 10, the coordinates of the contact position P < _b > ₂ of the finger 8 close to the imaging units 20 and 30 are small in the viewing direction from the imaging units 20 and 30. 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. 16, for example, two fingers 8A and 8B are placed on the surface of the light guide plate 10 at a point P _1.
And when contacted simultaneously to the point P _2, the imaging unit 20, 30, two fingers 8A-8B is likely to erroneously recognize that the present point P ₃ and the point P _4.

  Therefore, in the coordinate input device 3B of the present embodiment, as shown in FIG. 17, 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. 18, 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. 19, 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 image unit 70 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. 20, 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. 16 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.

  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 (device main body)
3B coordinate input device (device main unit)
4A Light source unit (light source)
4B Light source unit (light source)
4a LED
5 Optical coupling member 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)
9 Frame member 10 Light guide plate (light guide member)
11 Through-hole 11a Wall surface 12 Housing 12a Opening (first opening)
13a Propagating light 14 Double-sided tape (relaxation member)
15 Push rivet (relaxation member)
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)
91 Frame body (frame member)
92 Frame holding member (frame member)
92a opening (second opening)
L interval

Claims (8)

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 Provided on the edge of the light guide member in the apparatus body, and a device body having a 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 output of the light receiving means A coordinate input device provided with a frame member,
The coordinate input device according to claim 1, wherein the device main body is provided with a relaxation member that relieves stress generated in the frame member due to expansion and contraction of the light guide member and changes a relative position between the device main body and the frame member. It is arranged on the back side of the device body, and at least includes a housing for supporting the device body,
The coordinate input device according to claim 1, wherein the frame member is held in the casing by the relaxation member.   The coordinate input device according to claim 2, wherein the relaxation member is a double-sided tape. The casing and the frame member each have first and second openings that communicate with each other, and the relaxation member is inserted into both the first and second openings, A rivet locked to one of the first and second openings,
The coordinate input device according to claim 2, wherein, of the first and second openings, one of the openings that locks the rivet is smaller in size than the other opening.   The coordinate input device according to claim 1, wherein the light guide member is held by the frame member by the relaxation member.   The coordinate input device according to claim 5, wherein the relaxation member is a double-sided tape and is provided on both the front surface and the back surface of the light guide member. A coordinate input system comprising the coordinate input device according to any one of claims 1 to 6,
A coordinate input system comprising an image display module. A coordinate input system comprising the coordinate input device according to any one of claims 2 to 4,
It has an image display module,
The coordinate input system, wherein the casing is configured to support the image display module and the apparatus main body.

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