JP4484796B2 - Coordinate input device - Google Patents

Description

  The present invention relates to a coordinate input device that detects a designated position on a coordinate input area.

  A coordinate input device used to control a connected computer or to write characters, figures, etc. by inputting coordinates on a coordinate input surface by pointing with a pointing tool (for example, a dedicated input pen, finger, etc.) Exists.

  Conventionally, as this type of coordinate input device, various types of touch panels have been proposed or commercialized, and it is easy to operate terminals such as personal computers on the screen without using special equipment. Since it can be used, it is widely used.

  There are various coordinate input methods such as those using a resistive film and those using ultrasonic waves. For example, Patent Document 1 discloses a method using light. In Patent Document 1, a retroreflective sheet is provided outside the coordinate input area, and an illumination unit that illuminates light and a light receiving unit that receives the light are disposed at the corner ends of the coordinate input region. With this configuration, the angle between the light shielding unit and the light shielding unit that shields light such as a finger in the coordinate input area is detected, and the designated position of the light shielding object is determined based on the detection result.

  Further, as disclosed in Patent Documents 2 and 3 and the like, a coordinate input device is disclosed in which a retroreflective member is configured around a coordinate input region to detect the coordinates of a portion (light shielding portion) where the retroreflected light is shielded. .

  In these apparatuses, for example, in Patent Document 2, the angle of the light-shielding part relative to the light-receiving part is detected by detecting the peak of the light-shielding part by the shielding object received by the light-receiving part by waveform processing calculation such as differentiation, and the detection The coordinates of the shielding object are calculated from the result. Patent Document 3 discloses a configuration in which one end and the other end of a light shielding part are detected by comparison with a specific level pattern, and the center of those coordinates is detected.

  Here, a method of detecting coordinates and calculating coordinates as in Patent Documents 1 to 3 is hereinafter referred to as a light shielding method.

  Furthermore, in such a coordinate input device of the light shielding method, in particular, when the size of the coordinate input area is large, a plurality of operators are allowed to input simultaneously, improving convenience, There is a demand for more efficient applications such as meetings. Therefore, a coordinate input device corresponding to a plurality of simultaneous inputs has been devised.

  In Patent Documents 4 to 6, in order to input a plurality of coordinates simultaneously, the angles of a plurality of light shielding portions are detected by one light receiving sensor, and several input coordinate candidates are calculated from the combination of the angles of the sensors. . Furthermore, a technique for discriminating the actually input coordinates from the calculated input coordinate candidates is disclosed.

  For example, in the case of two-point input, the coordinates of a maximum of four points are calculated as input coordinate candidates, and two of the four points actually input are determined and output. That is, in this determination, actual input coordinates and false input coordinates are selected from a plurality of input coordinate candidates, and the final input coordinates are determined. This determination will be referred to as “false determination” here.

  As a concrete method of this truth determination, in Patent Document 5 and Patent Document 6, a distance sufficient to accurately calculate the coordinates instructed in the coordinate input area at both ends of one side of the conventional coordinate input area. First and second sensors are provided separately from each other. In addition to this, a third sensor is provided at a position between the first and second sensors at a sufficient distance to accurately calculate the coordinates instructed in the input area from the first and second sensors. . And the technique which performs this truth determination with respect to several angle information detected by the 1st and 2nd sensor based on the angle information different from the angle information of the 1st and 2nd sensor in this 3rd sensor is disclosed. Has been.

On the other hand, by arranging a plurality of sensor units around the coordinate input area with a predetermined interval and observing almost the same direction and almost the same area, even if a plurality of shading shadows overlap, A method has been proposed to avoid detection that is completely hidden behind the shadow of the camera. Also, a method has been proposed in which when a plurality of shadows overlap, the direction in which the shadow exists is detected by observing one end of each shadow.
U.S. Pat. No. 4,507,557 JP 2000-105671 A JP 2001-142642 A JP 2002-055570 A JP 2003-303046 A Patent registration No. 2896183

  In the above-described light shielding type coordinate input apparatus, all sensors must accurately detect shadows formed by blocking light based on standards consistent with each other in terms of the number, position, and shadow intensity. However, due to the positional relationship between the sensor and the retroreflective member, and the positional relationship between the light projecting unit and the light receiving unit in the sensor, the intensity of the shadow viewed from each sensor (the rate of decrease in light intensity due to light shielding) is not always necessarily. Each sensor does not have the same value.

  Hereinafter, the intensity of the shadow (light intensity reduction rate due to light shielding) is expressed as “light shielding depth”, “light shielding ratio”, “light shielding ratio”, and the like.

  In this way, if there is a difference in the shading depth of the shadow, for example, a shadow that should originally be detected simultaneously from a plurality of predetermined sensors is detected at a predetermined position in a specific sensor. In other specific sensors, a shadow to be detected at a predetermined position is not detected. In other words, this shadow may be missed.

  In this way, if any one of the sensors cannot detect a shadow that should be detected, the input coordinates cannot be detected correctly. In particular, this problem has a great effect when a plurality of inputs are performed simultaneously with a plurality of pointing devices. For example, when a shadow that should be detected by a certain sensor cannot be detected, it is erroneously recognized that the shadow overlaps with other shadows as viewed from the sensor. As a result, there is a possibility of detecting a position that is not originally possible and that is different from the position actually input by the pointing tool, that is, the coordinates of an incorrect position.

  In addition, when a plurality of sensors cannot detect a shadow that should originally be detected, there is a possibility that the number of shadows, that is, the number of inputs may be mistaken at the same time that the coordinates are distorted.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a coordinate input device that can accurately detect input coordinates.

In order to achieve the above object, a coordinate input device according to the present invention comprises the following arrangement. That is, a coordinate input device that detects a designated position on a coordinate input area,
A plurality of sensor means comprising: a light projecting unit that projects light to the coordinate input region; and a light receiving unit that receives incoming light;
A plurality of retroreflective means for recursively reflecting incident light;
Calculation means for calculating the coordinates of the indicated position of the instruction means based on the light amount distribution obtained from each of the plurality of sensor means by an instruction by the instruction means;
The three-dimensional shading detection area related to the plurality of sensor means has a common three-dimensional solid shape corresponding to the coordinate input area, and the three-dimensional shading detection area is a rate of change in observed light intensity. Is defined as a three-dimensional region in which a change in position in the height direction of the indicating means can be detected ,
Of the plurality of sensor means, one sensor means faces and the other sensor means does not face the shape of the retroreflective means,
The other sensor means;
A mirror image of the other sensor means with respect to the coordinate input area;
The retroreflective means facing the other sensor means;
A shape defined by a mirror image of the retroreflective means facing the coordinate input area of the other sensor means;
With respect to this shape, the three-dimensional solid shape is defined as a three-dimensional solid corresponding to the cross-sectional shape along the retroreflective means facing the one sensor means .

Also preferably,
The upper end of the first light-shielding detection window, which is a real image, is Opt1, the lower end is Opt2,
The upper end of the second light-shielding detection window that is a mirror image is Opt4 ′, the lower end is Opt3 ′,
The position of the first light shielding detection window on the coordinate input area is Opt0,
Ref1 is the upper end of the real image of the retroreflective means facing, Ref2 is the lower end,
The upper end of the mirror image of the retroreflective means is Ref1 ′, the lower end is Ref2 ′,
The position of the retroreflective means on the coordinate input area is Ref0,
The intersection of the line segment Ref2-Opt3 ′ and the line segment Ref0-Opt0 is defined as Q1,
The intersection of the line segment Ref1′-Opt2 and the line segment Ref0-Opt0 is defined as Q2,
The intersection of the line segment Ref1-Opt3 and the line segment Ref2-Opt1 ′ is defined as Q3,
The intersection of the line segment Ref2-Opt0 and the line segment Ref0_Opt2 is defined as Q4,
If
The upper side of the cross-section is at a position lower than the line segment Ref1-Opt1 and higher than the line segment Ref1-Q3-Opt1;
The lower side of the cross section is at a position lower than the line segment Ref2-Q4-Opt2 and higher than the line segment Ref2-Q1-Q2-Opt2.

Preferably, the Opt 1 is selected from the higher of the upper end of the light projecting window that is the light projecting range of the light projecting unit of the sensor means and the upper end of the light receiving window that is the light receiving range of the light receiving unit,
The Opt 2 is a higher one of the lower end of the light projecting window that is the light projecting range of the light projecting unit of the sensor means and the lower end of the light receiving window that is the light receiving range of the light receiving unit,
The Opt4 ′ is a mirror image of the coordinate input region of the lower selection result of the lower end of the light projecting window that is the light projecting range of the light projecting unit of the sensor means and the lower end of the light receiving window that is the light receiving range of the light receiving unit. Yes,
The Opt3 ′ is a mirror image of the coordinate input region of the selection result of the lower of the upper end of the light projecting window that is the light projecting range of the light projecting unit of the sensor means and the upper end of the light receiving window that is the light receiving range of the light receiving unit. is there.

Preferably, the plurality of sensor means are provided at both ends of one side of the coordinate input area,
The plurality of retroreflective means are provided on a side excluding the one side of the coordinate input area,
Of the plurality of sensor means , one of the sensor means faces and the other sensor means does not face the shape of the retroreflective means , and the other sensor means has an extension of one end of the retroreflective means. The end side of the other retroreflective means such that the light-shielding detection windows coincide with each other coincides with the end side of the retroreflective means opposed in common by the plurality of sensor means, and at least the lower side Is the shape of a bow.

  Preferably, the light-shielding detection window is a higher one of an upper end of a light projection window that is a portion that effectively contributes to light projection in the sensor means and a top end of the light reception window that is a portion that effectively contributes to light reception. The upper end of the light projecting window and the higher end of the lower end of the light receiving window.

  Preferably, the sensor means includes one optical unit including the light projecting unit and the light receiving unit.

  Preferably, the sensor means includes two optical units including the light projecting unit and the light receiving unit.

  ADVANTAGE OF THE INVENTION According to this invention, the coordinate input device which can detect the input coordinate accurately can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Embodiment 1>
FIG. 1A is a diagram showing an external configuration of a coordinate input device according to Embodiment 1 of the present invention.

  In FIG. 1A, L1 and L2 are optical units each having a light projecting unit and a light receiving unit, and a sensor unit 1L is constituted by these two sets of optical units. Similarly, R1 and R2 are optical units each having a light projecting unit and a light receiving unit, and a sensor unit 1R is configured by these two sets of optical units.

  In addition, the optical units L1 and L2 in the sensor unit 1L are arranged so as to project / receive light in substantially the same direction and the same field of view, and observe the incoming light with a predetermined parallax. Similarly, the optical units R1 and R2 in the sensor unit 1R are arranged to project / receive light in substantially the same direction and the same field of view, and observe the incoming light with a predetermined parallax.

  Further, the sensor units 1L and 1R are arranged at a predetermined distance apart in parallel to the X axis of the coordinate input effective area 3 which is a coordinate input surface as shown in the drawing and symmetrical to the Y axis. The sensor units 1L and 1R are connected to the control / arithmetic unit 2, receive a control signal from the control / arithmetic unit 2, and transmit the detected signal to the control / arithmetic unit 2.

  Reference numerals 4 a to 4 c denote retroreflective portions having retroreflective surfaces that reflect incident light in the direction of arrival, and are arranged on the three outer sides of the coordinate input effective area 3 as shown in the figure. The retroreflective portions 4a to 4c retroreflect the light projected from the sensor units 1L and 1R in a range of approximately 90 ° toward the sensor units 1L and 1R.

  The retroreflective portions 4a to 4c have a three-dimensional structure as viewed microscopically. At present, the retroreflective portions 4a to 4c are recursively arranged by regularly arranging mainly bead-type retroreflective tape or corner cubes. Retroreflective tape that causes the phenomenon is known.

  The light retroreflected by the retroreflecting units 4a to 4c is detected one-dimensionally by the sensor units 1L (optical units L1 and L2) and 1R (optical units R1 and R2), and the light quantity distribution is controlled / calculated unit 2. Sent to.

  The coordinate input effective area 3 is configured as a display screen of a display device such as a PDP, a rear projector, or an LCD panel, and can be used as an interactive input device.

  In such a configuration, when an input instruction is given to the coordinate input effective area 3 by an instruction means such as a finger or an indicator, the optical units L1 and L2 and the optical units R1 and R2 in the sensor units 1L and 1R, respectively. Light projected from the light projecting unit is blocked (a light shielding part). In this case, the light of the light shielding portion (reflected light due to retroreflection) cannot be detected by the optical units L1 and L2 and the light receiving portions of the optical units R1 and R2 in the sensor units 1L and 1R, respectively. Therefore, based on this detection status, it becomes possible for each of the optical units L1 and L2 to determine from which direction the light could not be detected.

  Therefore, the control / arithmetic unit 2 detects a plurality of light-shielding ranges of the portion instructed to be input by the pointing tool from the light amount change detected by the sensor units 1L (optical units L1 and L2) and 1R (optical units R1 and R2). To do. Next, the direction (angle) of the end of the light shielding range with respect to each of the sensor units 1L (optical units L1 and L2) and 1R (optical units R1 and R2) is calculated from the information on the light shielding range. When the pointing tool has a signal transmission unit, the pen signal receiving unit 5 receives a pen signal from the pointing tool.

  Then, based on the number of detected light shielding ranges, data obtained from the light shielding ranges used for coordinate calculation is determined. Next, based on the calculated direction (angle) and distance information between the sensor units 1L (optical units L1 and L2) and 1R (optical units R1 and R2), etc., the light of the pointing tool on the coordinate input effective area 3 is blocked. The position is calculated geometrically. Then, the coordinate value is output to an external terminal such as a host computer connected to the display device via the interface 7 (for example, USB, IEEE 1394, etc.).

  In this way, the operation of the external terminal such as drawing a line on the screen or operating an icon displayed on the display device can be performed by the pointing tool.

  In the following description, a direction perpendicular to the coordinate input effective area 3 is expressed as a height direction (Z direction), a direction close to the coordinate input effective area 3 is expressed as “down”, and a direction far from the coordinate input effective area 3 is expressed as “up”. In FIG. 1A, the sensor units 1L (optical units L1 and L2) and 1R (optical units R1 and R2) are expressed as a range where the light shielding is effectively detected, that is, the actual existence of the first light shielding detection window. Is done.

  That is, the semi-cylindrical thickness (Z direction) of the sensor units 1L (optical units L1 and L2) and 1R (optical units R1 and R2) is the size of an effective light shielding detection window defined in the height direction. is there.

  In particular, the definition of the first light shielding detection window in the height direction is not a light projecting window or a light receiving window of the sensor unit. Actually, when the indicator is inserted from the upper side in the very vicinity of the sensor unit to perform light shielding, the height at which the light shielding is actually detected is the upper end of the first light shielding detection window, and the light shielding ratio is substantially The height of 100% is used as the lower end of the first light shielding detection window. Such a window defined by the upper end and the lower end is defined as a first light shielding detection window.

  The light-shielding detection area is a part of the optical path from the time when the light projected from the sensor unit is retroreflected until it is received by the sensor unit. Sometimes it is defined as a region where the intensity of the received light decreases and that can be detected. Therefore, the shading detection area is defined as a height range at a certain coordinate position, and is defined as a three-dimensional area for a coordinate input effective area having a predetermined range. Further, a certain direction viewed from the sensor unit is defined as a two-dimensional region that forms a cross section of a three-dimensional region.

  By configuring in this way, when the light is shielded by the pointing tool, the sensor units 1L and 1R can always detect a shadow with a light shielding ratio of substantially the same level. 1B is a cross-sectional view added for easy understanding of the three-dimensional shape of the three-dimensional shading detection region, and is not a cross section that makes a special meaning in the present invention.

  In FIGS. 1A and 1B, an example of a compound eye (two-lens) configuration in which two optical units are built in one sensor unit is shown. However, as shown in FIGS. 2A and 2B, one sensor A monocular configuration in which one optical unit is built in the unit is also possible.

  Therefore, in the following, in order to simplify the description, FIGS. 3 to 23 will be described by taking the case of the monocular configuration of FIGS. 2A and 2B as an example, but the present invention is not limited to this. For example, the present invention can be applied even to the compound eye (two-eye) structure shown in FIGS. 1A and 1B or the compound eye structure in which three or more optical units are built in one sensor unit.

  However, in the case of a compound eye configuration, the following description is applied to each optical unit constituting the sensor unit. That is, in the case of a monocular configuration, the sensor unit and one optical unit built in the sensor unit can be described as being the same. On the other hand, in the case of a compound eye configuration, it should be noted that the description of FIGS. 3 to 23 is applied to each of a plurality of optical units constituting the sensor unit.

<Explanation of issues>
Here, the problem in the present invention will be described in detail with reference to the drawings.

  FIG. 3 is a diagram for explaining the problem in the present invention.

  Conventionally, the sensor units 1L and 1R and the retroreflective portion 4 (4a to 4c) have been designed to be as close to the coordinate input surface as possible. Further, as can be seen in the above-mentioned Patent Document 2, etc., in the sensor unit, by using an optical member such as a reflection mirror, the light projection position and the light reception position can be set to the same position and height as much as possible. It is mentioned that it approaches. Also, a coordinate input device that assumes that light projection / light reception is as parallel (collimated) as possible is mentioned.

  Here, it is assumed that the light projection / light reception is completely parallel to the thickness direction, and the retroreflective portion includes the light projection directivity range (field range) and the light reception directivity range (field range) in the thickness direction. Suppose that the shape and size are set. In this case, it can be said that the three-dimensional shading detection area is determined only by the light projecting or receiving light path, regardless of the shape of the retroreflective portion.

  Here, the thickness direction means a direction (Z direction) perpendicular to the coordinate input surface (coordinate input effective area 3).

  However, in practice, for example, there are many cases where light projection / light reception is sufficient in the thickness direction due to, for example, the relationship with a display screen that displays echo back, mounting restrictions due to the structure of the entire apparatus, and restrictions on cost, accuracy, etc. It cannot be said that it is in a state when collimation is possible.

  For this reason, in many cases, practically, the light projecting directivity range / light receiving directivity range of the optical unit is configured wider in the thickness direction than the width of the retroreflective portion (width in the thickness direction). In other words, the three-dimensional shading detection region is configured to be determined by the shape of the retroreflective portion by configuring the directivity range in the light emitting / receiving thickness direction to include the retroreflective portion.

  In particular, in the present invention, the directivity range in the thickness direction of light projection / light reception includes not only the retroreflective portion, but also a large part of the coordinate input surface, in particular, most of the portion excluding the vicinity of the sensor unit. It is configured to include.

  Here, there is a configuration in which the directivity range of light projection / directivity range of light reception includes a retroreflective portion and does not include a coordinate input surface, or the coordinate input surface does not reflect light.

  In contrast, in the present invention, the directivity range of light projection / the directivity range in the thickness direction of light reception includes not only the retroreflective portion but also most of the coordinate input surface except the vicinity of the sensor unit. .

  In either case, the actual configuration is established, but the accuracy of the sensor unit itself, the mounting accuracy, the rigidity of the entire structure, the manufacturing cost, and the design are less when the directivity range in the thickness direction is not limited. It is easy to handle in many aspects such as the degree of freedom.

  On the other hand, in such a case, the three-dimensional shading detection areas viewed from the sensor units 1L and 1R have a complicated shape, and the three-dimensional shading detection areas of the sensor units 1L and 1R are not necessarily common areas. There is no current situation.

  For this reason, the three-dimensional shading detection areas viewed from the respective sensor units 1L and 1R are compromised, and the three-dimensional shading detection areas of the sensor units 1L and 1R are not necessarily common areas. Currently.

  The present invention proposes a technique for solving the problems that occur in such a configuration.

  The problem will be described below with reference to FIG.

  In FIG. 3, the sensor units 1 </ b> L and 1 </ b> R are installed at higher positions with respect to the coordinate input effective area 3 that is the coordinate input surface as compared with the retroreflective portions 4 a to 4 c.

  Actually, when such a light-shielding coordinate input device is incorporated in or overlaid on a display device, this arrangement is often unavoidable.

  Since the sensor units 1L and 1R have a certain size, they cannot be installed in the black frame of the display screen (the outer portion that is not displayed on the same plane as the display surface). For this reason, the arrangement is such that it rides on the outer frame of the display device (a part protruding from the display surface, a so-called frame).

  On the other hand, there is a demand for the coordinate input device to make the light-shielding detection region as close as possible to the coordinate input surface in order to make the writing feel comfortable. Further, since there is an advantage of ease of mounting, as shown in FIG. 3, the elongated retroreflective portion is placed in the black frame of the display screen, that is, placed close to the display surface.

  Here, consider the three-dimensional shading detection area of each of the sensor units 1L and 1R.

  First, as shown in FIG. 4, part of the light projected from the light projecting unit of the sensor unit 1 </ b> L (1 </ b> R) reaches the retroreflecting unit 4 directly. Next, part of the retroreflected light directly reaches the light receiving unit, and part of the light is reflected by the coordinate input surface of the coordinate input effective area 3 and then reaches the light receiving unit.

  On the other hand, another part projected from the light projecting unit is reflected by the coordinate input surface of the coordinate input effective area 3 and then reaches the retroreflecting unit 4. Next, part of the retroreflected light directly reaches the light receiving unit, and part of the light is reflected by the coordinate input surface of the coordinate input effective area 3 and then reaches the light receiving unit.

  That is, in the case of this configuration, as shown in FIG. 4, the light to be shielded by the pointing tool can be divided into four optical paths (optical path 1, optical path 2, optical path 3, and optical path 4).

  Here, the retroreflection means that the projected light is reflected in the projected direction as it is, but in reality, the reflection direction is slightly wider than the projected direction. have. For example, even if the performance is quite good, the width at half maximum is about 1 to 2 degrees.

  Therefore, depending on the size of the sensor unit and the size of the coordinate input effective area 3, in many cases, the optical paths 1 to 4 are established, and the observation angles in the optical paths 2 and 3 (relative angle between the light projection and the reflected light). ) May not be negligible for the above half-value width. In this case, the optical paths 1 to 4 are established if the light intensity is considered to have an attenuation coefficient accordingly.

  Therefore, although it is an actual light-shielding detection region, with respect to the sensor unit 1L, the light projected from the sensor unit 1L returns to the light-receiving unit through the optical paths 1 to 4 with the opposing retroreflecting unit 4. Come. For this reason, as shown in FIG. 5A, the retroreflective portion facing the detection window of the sensor unit has a shape that is sandwiched between two surfaces that form a downward convex shape. The original shading detection area has a shape that is substantially in contact with the coordinate input surface.

  Similarly, a three-dimensional shading detection region as shown in FIG. 5B is also formed for the sensor unit 1R.

  As is clear from FIGS. 5A and 5B, the three-dimensional shading detection area relating to the sensor unit 1L and the three-dimensional shading detection area relating to the sensor unit 1R are three-dimensionally different. That is, the same three-dimensional shading detection area is not constituted between the two.

  Here, consider inserting an indicator at points C1 and C2 in FIG.

  At the point C1, as shown in FIG. 5A, the three-dimensional shading detection area related to the sensor unit 1L is close to the sensor unit 1L, and thus is at a relatively high position (a position away from the coordinate input surface).

  On the other hand, as shown in FIG. 5B, the three-dimensional shading detection region relating to the sensor unit 1R is close to the height of the nearby retroreflective portion 4b at the point C1, that is, a relatively low position (on the coordinate input surface). Close position).

  Here, the “pen tip height vs. shading rate” characteristic or “indicator height vs. shading rate” as shown in FIGS. 6A and 6B is considered. 6A and 6B, the horizontal axis represents the pen tip height H (that is, the distance between the effective tip of the pointing tool and the coordinate input surface). On the other hand, the vertical axis represents the light shielding rate in the sensor unit. For example, when the pointing tool is moved closer to the coordinate input surface, the vertical axis moves from right to left in FIGS. 6A and 6B.

  When the pointing tool is not inserted, the light shielding rate is 0% (standardized light intensity 100%). Further, when the pointing tool approaches a certain height position with respect to the coordinate input surface, the light shielding ratio starts to increase (the normalized light intensity starts to decrease). Thereafter, the light shielding rate reaches approximately 100% at a certain position, and then becomes constant.

  First, when the pointing tool is inserted at the position C1, the broken line in FIG. 6A is a locus indicating the displacement of the light shielding rate with respect to the sensor unit 1L, and the solid line is related to the sensor unit 1R.

  In the vicinity of the point C1, since the three-dimensional shading detection region related to the sensor unit 1L is at a high position, the portion where the locus of the broken line shown in FIG.

  On the other hand, since the three-dimensional shading detection region relating to the sensor unit 1R has a relationship that substantially matches the height of the retroreflective portion 4b, the solid line locus shown in FIG.

  That is, it can be said that the part that greatly changes is a part that passes through the three-dimensional shading detection region of each of the sensor units 1L and 1R.

  In the configurations shown in FIGS. 3, 5A, and 5B, the three-dimensional shading detection area for the sensor unit 1L is higher in the vicinity of the point C1 than the three-dimensional shading detection area for the sensor unit 1R. Thin relative to direction. Therefore, in FIG. 6A, the portion where the locus (curve) of the light shielding rate changes is narrower and steeper in the sensor unit 1L than in the sensor unit 1R.

  As described above, in the conventional configuration, the “pen tip height vs. light shielding rate” characteristics detected by the left and right sensor units 1L and 1R are different.

  When the light shielding detection is performed with such characteristics, the following problems occur.

  For example, it is assumed that there is a shadow in the following case. When the pointing tool is inserted into the coordinate input surface from above and its height H reaches the range indicated by Hth_R ≦ H ≦ Hth_L in FIG. 6A, each of the sensor units 1L and 1R detects it. This is the time when the intensity of the shadow, that is, the light shielding rate exceeds the predetermined threshold thsh0.

  In such a configuration, the sensor unit 1L first detects a shadow when H = Hth_L. On the other hand, the sensor unit 1R first detects a shadow when H = Hth_R.

  Therefore, in the range indicated by Hth_R ≦ H ≦ Hth_L, the shadow of the pointing tool is observed in the sensor unit 1L but not in the sensor unit 1R.

  Similarly, the case of point C2 is shown in FIG. 6B. In the vicinity of the point C2, the three-dimensional shading detection area related to the sensor unit 1L is close to the coordinate input surface due to the influence of the reflection of the coordinate input surface. On the other hand, the three-dimensional shading detection area related to the sensor unit 1R has a relationship that substantially matches the height of the retroreflective portion 4b.

  Accordingly, as shown in FIG. 6B, when the pointing tool is inserted at the position of point C2, the broken line in FIG. 6B is a locus indicating the displacement of the light shielding rate with respect to the sensor unit 1L, and the solid line is the sensor unit 1R. It is about.

  In the vicinity of the point C2, the three-dimensional shading detection region related to the sensor unit 1L is close to the coordinate input surface due to the reflection of the coordinate input surface, that is, at a low position. The part where changes greatly is to the left.

  On the other hand, since the three-dimensional shading detection area related to the sensor unit 1R has a relationship that substantially coincides with the height of the retroreflective portion 4b, the locus of the solid line shown in FIG.

  That is, it can be said that the part that greatly changes is a part that passes through the three-dimensional shading detection region of each of the sensor units 1L and 1R.

  When the light shielding detection is performed with such characteristics, the following problems occur.

  In such a configuration, the sensor unit 1L first detects a shadow when H = Hth_L. On the other hand, the sensor unit 1R first detects a shadow when H = Hth_R. Therefore, in the range indicated by Hth_L ≦ H ≦ Hth_R, the shadow of the pointing tool is observed in the sensor unit 1L but not in the sensor unit 1R.

  What has been described so far becomes a serious problem when simultaneous input (multiple input operation) is performed using a plurality of pointing devices.

  Hereinafter, the problem at the time of multiple input will be described. First, in explaining this problem, coordinate detection at the time of single input will be explained.

  FIG. 7 is a top view of the single input operation in FIG.

  In FIG. 7, when an input is made at the position of the point C1, a shadow is usually formed at the positions of θL and θR in FIGS. Here, FIG. 8 shows the shape of the shadow detected by each of the sensor units 1L and 1R when the height of the pointing tool is H ≦ H2_R (that is, when the pointing tool is sufficiently close to the coordinate input surface). . FIG. 9 shows the shadow shapes detected by the sensor units 1L and 1R when Hth_R ≦ H ≦ Hth_L (that is, when the pointing device enters or exits the coordinate input effective area). Yes.

  At this time, as described above, the shadow of the pointing tool is detected from the sensor unit 1L, and the shadow of the pointing tool is not detected from the sensor unit 1R.

  Here, in the case of a single input, there is no problem if it is treated as having an input (no input when only one of the two sensor units detects a shadow).

  However, in the case of multiple inputs, the problem is great. This will be described below.

  FIG. 10 is a view of a multi-input operation as viewed from above.

  FIG. 10 shows a case where a plurality of inputs are performed at points P12 and P21.

  In this case, as shown in FIG. 11, in the sensor unit 1L, a shadow is detected at the positions of θL1 and θL2. In the sensor unit 1R, a shadow is detected at the positions of θR1 and θR2. Based on these two sets of angle data, four coordinate candidate points P11, P12, P21 and P22 are calculated. From these coordinate candidate points, by determining whether the coordinates are true by some means, for example, it is determined that P11 and P22 are virtual images and P12 and P21 are real images, and the coordinate input points are determined. Become.

  Next, an example of a plurality of inputs when a coordinate input point is erroneously detected will be described. The false detection pattern (1) is as follows. That is, as shown in FIG. 12, when a plurality of inputs are made at point P12 (corresponding to point C1 in FIG. 7) and point P21, the height H of the pointing tool at each point is Hth_R ≦ H shown in FIG. Consider the case of ≦ Hth_L.

  At this time, as shown in FIG. 13, the sensor unit 1R does not detect θR2.

  In this case, in practice, although two inputs are made at the positions of C1 point (P12) and P21, only θR1 is detected and θR2 is not detected from the sensor unit 1R (ie, input of P12). Is not observed). For this reason, P12 is erroneously recognized as a point observed from the sensor unit 1R, that is, P11 in FIG. 12 is a coordinate input point. That is, the original coordinate input point P12 is erroneously detected as the coordinate input point P11.

  Next, the false detection pattern (2) is as follows. That is, as shown in FIG. 14, a plurality of inputs are performed at point P12 (corresponding to point C1 in FIG. 7) and point P21 (point C1 'that is approximately symmetrical with respect to point C1). In this case, the height H of the pointing tool at the position of the point C1 is Hth_R ≦ H ≦ Hth_L shown in FIG. 6B, and the height H of the pointing tool at the position of the point C1 ′ is the sensor unit 1L and 1R in FIG. 6B. This is a relationship in which the relationship with is replaced. Further, Hth_L (C1 ′) ≦ H (C1 ′) ≦ Hth_R (C1 ′).

  At this time, as shown in FIG. 15, θL2 is not observed from the sensor unit 1L, and similarly, θR2 is not observed from the sensor unit 1R. In this case, in fact, although the values are input to C1 (P12) and C1 ′ (P21), the intersections of the angles θL1 and θR1 actually detected, that is, P11 in FIG. Misrecognized as an input point. That is, in this case, a single input is erroneously detected.

  As described above, when the height H of the pointing device is within a predetermined range (for example, Hth_R ≦ H ≦ Hth_L in the case of the position of the C1 point), a shadow that should be originally detected by both the sensor units 1L and 1R Each three-dimensional shading detection area is different. For this reason, the coordinate input point cannot be detected by a correct combination from the coordinate candidate points detected at the time of a plurality of inputs.

  Further, this predetermined range (for example, Hth_R ≦ H ≦ Hth_L in the case of the position of the point C1) always exists when the pointing tool enters or leaves the coordinate input effective area. For this reason, erroneous detection of coordinates and erroneous calculation of coordinate candidate points occur.

  The same problem occurs at point C2. In the case of point C2, the relationship between the intensity of the shadow seen from the sensor unit 1L and the intensity of the shadow seen from the sensor unit 1R is opposite.

  Accordingly, the pattern shown in FIG. 16A corresponds to the pattern shown in FIG. 12 at the point C1. In this case, at the moment when no shadow in the θL1 direction is visible from the sensor unit 1L, the coordinates of C2 (P12) are mistakenly detected as P22.

  Further, the pattern shown in FIG. 16B corresponds to the pattern shown in FIG. 14 at the point C1. In this case, at the moment when θL1 cannot be seen from the sensor unit 1L and θR1 cannot be seen from the sensor unit 1R, it is seen at the position of P22 even though it is inputted to C2 (P12) and C2 ′ (P21). It will be detected by mistake.

<Shared 3D shading detection area>
Therefore, the present invention proposes a configuration that solves these problems. In particular, in the present invention, the three-dimensional shading detection areas of the left and right sensor units 1L and 1R are made identical (common). To solve these problems.

<Definition of common 3D shading detection area>
First, the configuration proposed in the present invention is, for example, how to make the three-dimensional shading detection areas of the sensor units 1L and 1R shown in FIGS. 5A and 5B the same space.

  For this reason, in the present invention, the following configuration (characteristic condition) is adopted.

  In a light-shielding coordinate input device composed of two sensor units, a retroreflective portion in which only one of the three-dimensional light-shielding detection areas related to the other is shaped in the shape of a retroreflective portion in which only one of the sensor units faces each other. The cross section in the plane along

  Specifically, the cross section in the vicinity of the left side of the three-dimensional shading detection region related to the sensor unit 1L and the shape of the retroreflective portion 4b facing the sensor unit 1R and not facing the sensor unit 1L are made substantially the same.

  Similarly, the cross section in the vicinity of the right side of the three-dimensional shading detection area related to the sensor unit 1R and the shape of the retroreflective portion 4a facing the sensor unit 1L and not facing the sensor unit 1R are made substantially the same.

  Actually, in order to do this, as shown in FIG. 2A, for example, the shape of the retroreflective portion 4a is such that the extension of one end of the side is not opposed to the first light shielding detection window of the sensor unit 1R. Is approximately the same. Further, the side of the other end substantially coincides with the side of the end of the retroreflective portion 4c facing the sensor unit 1L and the sensor unit 1R in common. Furthermore, the lower side of the retroreflective portion 4a has a bow-like shape, and the middle part is close to (nearly coincident with or close to) the coordinate input surface, and the upper side is a straight line or a bow that falls downward in the middle. It is the shape.

  Similarly, in the shape of the retroreflective portion 4b, the extension of the side of one end portion substantially coincides with the first light shielding detection window of the sensor unit 1L that is not opposed. Further, the side of the other end substantially coincides with the side of the end of the retroreflective portion 4c facing the sensor unit 1L and the sensor unit 1R in common. Furthermore, the lower side of the retroreflective portion 4b has a bow-like shape, which is a shape that substantially matches or approaches the input surface in the middle part, and the upper side is a straight line or a bow-like shape that falls down in the middle. .

  By adopting such a shape, the common three-dimensional shading detection area is such that the surrounding cross-section is a retroreflective portion of each surface, and the upper and lower surfaces are depressed downward in the middle of the coordinate input area. Shape. In addition, the lower surface is formed in the middle of the coordinate input area and in a shape that substantially touches or approaches the coordinate input surface.

  Specifically, the retroreflective portions 4a and 4b in FIG. 2A are shaped as shown in the figure so that the three-dimensional light shielding detection region shown in FIG. 2B, that is, the three-dimensional light shielding common to the sensor units 1L and 1R. A detection region can be formed.

  Here, the vertical stripes in FIG. 2B are sectional views added for easy understanding of the three-dimensional shape of the three-dimensional shading detection region, and are not special in the present invention.

  In addition, as shown to FIG. 2A, the retroreflection part 4c is a rectangle. The retroreflective portions 4a and 4b have the same shape, in which the sides of both ends and the detection position of the sensor unit are connected by a bow-like shape, and the shape is substantially in contact with the coordinate input surface in the vicinity of the central portion. .

  The upper end of the sensor unit 1L is on the extension of the upper side of the retroreflective portion 4b, and the lower end is on the extension of the lower side. The upper end of the sensor unit 1R is on the extension of the upper side of the retroreflective portion 4a, and the lower end is on the extension of the lower side.

<Cross-sectional shape of three-dimensional shading detection area>
Next, a method for determining the shapes of the retroreflective portions 4a and 4b, that is, the cross-sectional shape of the three-dimensional shading detection region will be described.

  As already described, the light that is projected from the light projecting unit of the sensor unit and returned to the light receiving unit is assumed to have four optical paths, that is, optical path 1 to optical path 4, as shown in FIG.

  The order of transmission for each optical path is summarized as follows.

Optical path 1: Projection → Retroreflection → Reception Optical path 2: Projection → Retroreflection → Coordinate input surface reflection → Reception Optical path 3: Projection → Coordinate input surface reflection → Retroreflection → Reception Optical path 4: Projection → Coordinate input surface reflection → Recursive reflection → Coordinate input surface reflection → Light reception Next, the relationship between these optical paths and the light shielding detection area will be described with reference to FIGS. 17A to 17C and FIGS. 18A to 18C.

  About FIG. 17A-FIG. 17C, the optical path 1 and the optical path 2 are shown in the upper part in a figure, and the optical path 3 and the optical path 4 are shown in the lower part in a figure. 18A to 18C, the optical path 1 and the optical path 3 are shown in the upper part of the figure, and the optical path 2 and the optical path 4 are shown in the lower part of the figure.

  For all the figures related here, the effective light passage area on the light emitting side (from the light projecting part to the retroreflective part) is expressed by a lattice pattern, and the effective light receiving side (from the retroreflective part to the light receiving part) is expressed. The light passage area is represented by a gray pattern.

  Regarding the positional relationship between the light projecting unit and the light receiving unit in the sensor unit, FIG. 17A shows a case where the light projecting unit is located higher than the light receiving unit and there is no overlapping portion between the two. FIG. 17B shows a case where the light projecting unit is at a higher position than the light receiving unit, and there is an overlapping portion between them. FIG. 17C illustrates a case where the light projecting unit includes the light receiving unit at a position in the height direction.

  FIG. 18A shows a case where the light receiving unit is at a higher position than the light projecting unit and there is no overlapping portion. FIG. 18B shows a case where the light receiving unit is at a higher position than the light projecting unit and there is an overlapping portion of both. FIG. 18C shows a case where the light receiving unit includes the light projecting unit at a position in the height direction.

  Comparing these figures, FIGS. 17A to 17C and FIGS. 18A to 18C are the same shape except that the positions of the lattice pattern and the gray pattern shown in FIG. 17 are interchanged.

  Next, in each of these cases, the positional relationship between the indicator for detecting light shielding and the light passage region is determined, and by generalizing and integrating the determination results, the left and right light shielding detection regions, that is, A cross-sectional shape in the vicinity of the left and right sides of the three-dimensional shading detection area is determined.

  For the sake of explanation, terms are defined as follows.

  Shielding rate 0% boundary line: A boundary line that first detects light shielding when an indicator is inserted from above in a predetermined optical path.

  Shielding rate 100% boundary line: A boundary line where the shielding rate reaches 100% when an indicator is inserted from above in a predetermined optical path.

  Hereinafter, each case will be described.

  17A shows the optical path 1 and the optical path 2, and the lower figure shows the optical path 3 and the optical path 4. FIG.

  In the upper diagram of FIG. 17A, the 0% light shielding rate boundary line is a line segment (Ref1, Led1) indicated by a two-dot chain line. Further, the 100% light shielding rate boundary line is a line segment (Ref2, Led2) indicated by a dotted line.

  In the upper diagram of FIG. 17A, a gray pattern, that is, a retroreflective → light-receiving portion of the optical path 1 and the optical path 2 exists in a portion below the line segment (Ref2, Led2). However, since the light path on the light projecting side is completely blocked in the line segment (Ref2, Led2), it can be said that this portion is not directly related to determining the 100% light shielding rate boundary line.

  In the lower diagram of FIG. 17A, the 0% light shielding rate boundary line is a dotted line portion determined by the line segment (Ref1, Sens1) and the line segment (Ref2 ′, Led1). Further, the 100% light shielding rate boundary line is a line segment (Ref 2, Sens 1 ′), a line segment (Ref 1 ′, Led 2), and a one-dot chain line portion determined by the coordinate input surface 3.

  In the portion below the one-dot chain line, for example, there is a light path on the light projecting side on the retroreflective side and a light path on the light receiving side on the sensor unit side. Here, in the former, the light-receiving side is completely shielded from the one-dot chain line, and in the latter, the light-projecting side in the one-dot chain line is completely shielded. As a result, the lower part is not directly related to determining the 100% light shielding rate boundary line.

  Actually, by considering both the upper and lower figures, the 100% light shielding rate boundary line and the light shielding rate 0% boundary line in the optical paths 1 to 4 are determined.

  In other words, the 0% light shielding rate boundary line of the optical paths 1 to 4 as a whole is the boundary line of the light shielding rate 0% for the optical path 1 and the optical path 2 (upper figure) and the 0% light shielding rate boundary line for the optical path 3 and the optical path 4 (lower figure) It is determined by the higher position. Similarly, the 100% light shielding rate boundary line of the optical paths 1 to 4 as a whole is the boundary between the light shielding rate 100% of the optical path 1 and the optical path 2 (upper diagram) and the light shielding rate 100% boundary of the optical path 3 and the optical path 4 (lower diagram). Determined by the lower position of the line.

  That is, in each optical path, a position where at least one of the light projecting side or the light receiving side begins to be shielded is a boundary line with a light shielding rate of 0% at that location. Further, the position where one of the light projecting side or the light receiving side is completely shielded is a boundary line with 100% light shielding rate at that place.

  That is, the 0% light shielding rate boundary line at the highest position among the optical paths 1 to 4 at that location is the 0% light shielding rate boundary line as a whole of the light paths 1 to 4 at that location. Further, the 100% light shielding rate boundary line at the lowest position in the optical paths 1 to 4 is the 100% light shielding rate boundary line as a whole of the optical paths 1 to 4 in that place.

  In FIG. 17A, a boundary line with a light shielding rate of 0% for the entire light paths 1 to 4 is indicated by a two-dot chain line, and a boundary line with a light shielding ratio of 100% for the whole light paths 1 to 4 is indicated by a one-dot chain line. Similarly, in FIGS. 17B to 18C, a boundary line with a light shielding rate of 0% for the entire optical paths 1 to 4 is indicated by a two-dot chain line, and a boundary line with a light shielding ratio of 100% for the entire optical paths 1 to 4 is indicated by a one-dot chain line.

  Here, in each figure, the light shielding rate 0% boundary line and the light shielding rate 100% boundary line are Sens1, Sens2, Sens1 ′, Sens2 ′, Led1, Led2, Led1 ′, Led2 ′, and Ref1, Ref2, It is expressed by a combination of Ref1 ′ and Ref2 ′.

Here, terms are defined as follows: Opt1 = higer (Led1, Sens1)
Opt2 = higer (Led2, Sens2)
Opt3 = lower (Led1, Sens1)
Here, higer (* 1, * 2) represents an arithmetic expression that selects a higher position in the Z direction of * 1 and * 2.

  When defined in this way, as shown in FIG. 19A, the 0% light shielding rate boundary line as a whole of the optical paths 1 to 4 is always a line segment (Ref1, Opt1), and the light shielding rate 100% boundary line is always a line segment (Ref2, Q1). , Q2, Opt2).

  Here, as shown in FIG. 19B, a line segment (Ref1, Q3, Opt1) is set as a third light shielding rate boundary line, separately from the light shielding rate 0% boundary line and the light shielding rate 100% boundary line. This is a boundary line in which all of the four optical paths 1 to 4 generate an effective light shielding rate. That is, any one of the optical paths 1 to 4 is shielded according to the height of the pointing tool between the boundary line with the light shielding rate of 0% and the third light shielding ratio boundary line. Further, below the third boundary line, all of the optical paths 1 to 4 are shielded according to the height of the pointing tool.

  Here, as the definition of the first light shielding detection window, the upper end is Opt1 and the lower end is Opt2. In addition, as the definition of the second light shielding detection window that is a mirror image of the coordinate input effective area 3 of the first light shielding detection window, the upper end is Opt4 'and the lower end is Opt3'.

  If it defines in this way, it can be said that the 1st shading detection window actually means the shading detection window in the real image of a sensor unit. Moreover, it can be said that the 2nd light-shielding detection window actually means the light-shielding detection window in the mirror image of a sensor unit. Further, Opt3, Opt4, Ref1, Ref1 ', Ref2, Ref2' and the intersection positions Q1, Q2, Q3 can be referred to as parameter groups for determining the light shielding detection region.

  By configuring as described above, the cross-sectional shape of the three-dimensional shading detection region as a region sandwiched between the two-dot chain line (the light shielding rate 0% boundary line) and the one dot chain line (the light shielding 0% boundary line) in FIG. Can be determined.

  In other words, of the plurality of sensor units 1L and 1R, the shape of the retroreflective portion where one sensor unit faces and the other sensor unit does not face is a shape defined by the following conditions. That is, 1) the other sensor unit, 2) the mirror image of the other sensor unit with respect to the coordinate input effective area, 3) the retroreflective portion facing the other sensor unit, and 4) the retroreflecting portion facing the other sensor unit. This is a shape defined by a mirror image of the coordinate input area. Then, the three-dimensional light-shielding detection region is defined so that the shape of the cross section along the retroreflecting portion facing one sensor unit is substantially equal to this shape.

  More specifically, the shape of the cross section can be expressed as follows.

  First, as the premise, the upper end of the first light-shielding detection window, which is a real image, is Opt1, and the lower end is Opt2. The upper end of the second light-shielding detection window, which is a mirror image, is Opt4 'and the lower end is Opt3'. The position of the first light shielding detection window on the coordinate input effective area is Opt0. Let Ref1 be the upper end of the real image of the retroreflective part facing, and Ref2 be the lower end. The upper end of the mirror image of the retroreflective portion is Ref1 ', and the lower end is Ref2'. The position of the retroreflective portion on the coordinate input effective area is Ref0.

  Further, the intersection of the line segment Ref2-Opt3 'and the line segment Ref0-Opt0 is defined as Q1. Let Q2 be the intersection of the line segment Ref1'-Opt2 and the line segment Ref0-Opt0. The intersection of the line segment Ref1-Opt3 and the line segment Ref2-Opt1 'is defined as Q3. Let Q4 be the intersection of the line segment Ref2-Opt0 and the line segment Ref0_Opt2.

  In this case, the upper side of the cross section is lower than the line segment Ref1-Opt1 and higher than the line segment Ref1-Q3-Opt1. The lower side of the cross section is lower than the line segment Ref2-Q4-Opt2 and higher than the line segment Ref2-Q1-Q2-Opt2.

<Realistic cross-sectional shape>
Here, for example, consider the “indicator height vs. shading rate” characteristic at point B in FIG. 19A. Therefore, this “indicator height vs. shading rate” characteristic is shown in FIG.

  As described above, at the point B, the light shielding detection starts at the point B1 (the height of the boundary line where the light shielding rate is 0% at the point B) and the light is shielded at the point B4 (the height of the boundary line where the light shielding rate is 0% at the point B). It is true that the rate reaches 100%.

  However, at the point B, the manner in which each of the light paths 1 to 4 is related to the light shielding detection is different for each partial section between the points B1 to B4. For example, at the points B1 to B2, there are only two of the optical paths 1 to 4 for the light shielding detection. In addition, although depending on the case, there are cases where the number of optical paths related to the light blocking detection is smaller in the B3 to B4 portion than in the B2 to B3 portion.

  Due to these relationships, the actual “indicator height vs. shading rate” at point B is a curve as shown in FIG. That is, the gradient between B1 and B2 and between B3 and B4 is relatively gentle, and the gradient between B2 and B3 is relatively steep.

  As already described with reference to FIGS. 6A and 6B, in the present invention, the cross-section of the three-dimensional shading detection region and the retroreflective shape positioned in the cross-section are substantially equal to the following. is there. In other words, in FIG. 6A and FIG. 6B, by devising the retroreflective shape of the “indicator height vs. shading rate” curve shown by the broken line, the “indicator height vs. shading rate” curve shown by the solid line It means that the shape will be matched.

  Therefore, when this idea is applied to FIG. 20, the following can be said. In other words, in order to make the straight line indicated by the solid line and the curve indicated by the broken line closest to each other, instead of connecting B1 and B4 and B2 and B3 with a straight line, respectively, a predetermined portion between B1 and B2 and B3 and B4 It is appropriate to connect

  That is, assuming that the point H1_B in FIG. 20 belongs to a boundary line with a light shielding rate of 0% in a practical sense and the point H2_B belongs to a boundary line with a light shielding rate of 100% in a practical sense, the following can be said. . That is, in FIG. 19A, a realistic light shielding rate 0% curve is not a two-dot chain line in the same figure, but passes slightly below the two-dot chain line as it gets away from the points at both ends, Ref1 or Opt1. Become. Further, the actual 100% light-shielding rate curve is not the one-dot chain line in the figure, but passes a little higher than the one-dot chain line as it gets away from the points at both ends, Ref2 or Opt2.

<Extended definition of common 3D shading detection area>
As described so far, the configuration of the present invention is, for example, how to make the three-dimensional shading detection areas of the sensor units 1L and 1R the same space. Therefore, of the sensor units 1L and 1R, the shape of the retroreflective portion facing only one of the sensor units 1L and 1R is substantially equal to the cross section of the surface along the retroreflective portion facing only the one of the three-dimensional shading detection regions related to the other. To do.

  Specifically, the cross section in the vicinity of the left side of the three-dimensional shading detection region related to the sensor unit 1L and the shape of the retroreflective portion 4b facing the sensor unit 1R are made substantially the same. Similarly, the cross section in the vicinity of the right side of the three-dimensional shading detection region related to the sensor unit 1R and the shape of the retroreflective portion 4a facing the sensor unit 1L are made substantially the same.

  Therefore, as shown in FIG. 2A, the shapes of the retroreflective portions 4a and 4b are not necessarily symmetrical. For example, as shown in FIG. 21, when the heights of the sensor units 1L and 1R are different from each other, the height of both ends of the retroreflective portion 4c common to both may be different. Or as shown in FIG. 22, when the sizes of the light-shielding detection windows of the sensor units 1L and 1R are different from each other, the height of both ends of the retroreflective portion 4c common to both may be different.

  The same can be said for a coordinate input apparatus including three or more sensor units as shown in FIG. 23, not limited to the above two sensor units.

By configuring as described above, the three-dimensional shading detection areas for the respective sensor units become substantially the same solid (three-dimensional solid shape), and the depth of the shading shadow observed by the respective sensor units 1L and 1R. The length (light shielding rate) is observed as substantially the same value. In other words, it is possible to detect a change in the position of the indicator in the height direction based on the observed change rate of the light intensity. As described above, the conditions described so far are only when there is an input by the indicator. This means that the shadow depth (light shielding ratio) observed by the sensor units can be observed at substantially the same value by all the sensor units, and is not a condition for calculating the correct coordinates.

  In other words, in order to calculate correct coordinates, it goes without saying that each retroreflecting unit and each sensor unit must be arranged in a plane in an appropriate relationship in the direction of the coordinate input surface.

  Of course, Embodiment 1 of the present invention and Embodiment 2 described later also satisfy the above-mentioned conditions.

<Coordinate detection principle>
The coordinate detection principle in the first embodiment will be described.

  FIG. 24 is a diagram for explaining the principle of coordinate detection according to the first embodiment of the present invention.

  Here, FIG. 24 is a schematic diagram when the coordinate input device of FIG. 1A (or FIG. 2A) is viewed from above. Further, hereinafter, in the description with reference to FIG. 1A (or FIG. 2A) and FIG. 24, the retroreflective portions 4a to 4c are collectively referred to as the retroreflective portion 4 as necessary.

<Detailed description of sensor unit 1>
Next, the configuration in the sensor units 1L and 1R will be described with reference to FIG. Here, a case where the sensor units 1L and 1R have a twin-lens configuration in which the optical units L1 and L2 and the optical units R1 and R2 are incorporated will be described as an example.

  FIG. 25 is a diagram showing a detailed configuration of the sensor unit according to the first embodiment of the present invention.

  In FIG. 25, 101A and 101B are infrared LEDs which emit infrared light, and project light in a range of approximately 90 ° toward the retroreflecting unit 4 by the light projecting lenses 102A and 102B, respectively. Here, the light projecting units in the sensor units 1L and 1R are realized by the infrared LEDs 101A and 101B and the light projecting lenses 102A and 102B. Thereby, each of the sensor units 1L and 1R includes two light projecting units.

  Then, the infrared light projected from the light projecting unit is retroreflected in the arrival direction by the retroreflecting unit 4, and the light is detected by the light receiving units in the sensor units 1L and 1R.

  The light receiving unit includes a one-dimensional line CCD 104 provided with a shield member 105 that restricts the field of view of light and provides an electrical shield. In addition, light receiving lenses (for example, fθ lenses) 106A and 106B as condensing optical systems, diaphragms 108A and 108B that roughly limit the incident direction of incident light, and incident of extraneous light (disturbance light) such as visible light. Infrared filters 107A and 107B for preventing are provided.

  The light reflected by the retroreflecting unit 4 passes through the infrared filters 107A and 107B and the stops 108A and 108B, and is collected on the detection element 110 surface of the line CCD 104 by the light receiving lenses 106A and 106B. Thereby, each of the sensor units 1L and 1R includes two light receiving units.

  The member 103 and the member 109 are arranged to dispose the optical components constituting the light projecting unit and the light receiving unit, and prevent light projected by the light projecting unit from directly entering the light receiving unit, or to cut off external light. It functions as an upper hood 103 and a lower hood 109.

  In the first embodiment, the apertures 108A and 108B are integrally formed with the lower hood 109, but it goes without saying that they may be separate parts. Furthermore, positioning portions for the diaphragms 108A and 108B and the light receiving lenses 106A and 106B may be provided on the upper hood 103 side. Accordingly, it is possible to realize a configuration that facilitates positioning of the light receiving unit with respect to the light emission center of the light projecting unit (that is, a configuration in which all the main optical components are arranged only by the upper hood 103).

  26A is a view of the assembled state of the sensor unit 1L (1R) in the state of FIG. 25 as viewed from the front direction (perpendicular to the coordinate input surface). As shown in FIG. 26A, the two light projecting units in the sensor unit 1L (1R) are arranged so that their principal ray directions are substantially parallel with a predetermined distance d therebetween. These are configured to project light in a range of approximately 90 ° by the light projecting lenses 102A and 102B.

  FIG. 26B is a cross-sectional view of the portion indicated by the thick arrow in FIG. 26A. Here, the light from the infrared LED 101A (101B) is mainly projected onto the retroreflecting unit 4 as a light beam limited substantially parallel to the coordinate input surface by the projection lens 102A (102B). It is constituted so that.

  On the other hand, FIG. 26C is a view of the state in which the infrared LEDs 101A and 101B, the projection lenses 102A and 102B, and the upper hood 103 in FIG. 26A are removed as viewed from the front direction (perpendicular to the coordinate input surface).

  Here, in the case of the first embodiment, the light projecting unit and the light receiving unit have an arrangement configuration (see FIG. 26B) that overlaps the vertical direction of the coordinate input effective area 3 that is the coordinate input surface. In addition, when viewed from the front direction (perpendicular to the coordinate input surface), the light emission center of the light projecting unit matches the reference position of the light receiving unit.

  Here, the reference position corresponds to a reference point position for measuring an angle. In the first embodiment, the reference position is the position of the stop 108A (108B), which is a point where the light rays in the drawing intersect.

  Therefore, as described above, since the two light projecting portions are arranged so as to be substantially parallel to each other in the principal ray direction with a predetermined distance d apart, the two light receiving portions are similarly separated by the predetermined distance d. And each optical axis (optical symmetry axis) is substantially parallel.

  In addition, light that is approximately parallel to the coordinate input surface projected by the light projecting unit and is projected in a direction of approximately 90 ° in the in-plane direction is recursed in the light arrival direction by the retroreflecting unit 4. Reflected. Thereafter, the light passes through the infrared filter 107A (107B), the stop 108A (108B), and the condenser lens 106A (106B), and is condensed and imaged on the detection element 110 surface of the line CCD 104.

  Accordingly, since the output signal of the line CCD 104 outputs a light amount distribution corresponding to the incident angle of the reflected light, the pixel number of each pixel constituting the line CCD 104 indicates angle information.

  Note that the distance L between the light projecting unit and the light receiving unit shown in FIG. 26B is sufficiently smaller than the distance from the light projecting unit to the retroreflective unit 4, and sufficient retroreflection is possible even if the distance L is present. The light can be detected by the light receiving unit.

  As described above, the sensor unit 1L (1R) includes at least two light projecting units and two light receiving units that detect the light projected by each of the light projecting units (in the case of the first embodiment, the light projecting). Part has two sets and the light receiving part has two sets).

  Further, in the first embodiment, the left side portion of the detection elements 110 arranged in a line in the line CCD 104 which is a part of the light receiving unit is the condensing region of the first light receiving unit, and the right side portion is the second light receiving unit. Condensation area. Thus, the parts are shared, but the present invention is not limited to this. Needless to say, a line CCD may be provided for each light receiving unit.

<Description of control / arithmetic unit>
Between the control / arithmetic unit 2 and the sensor units 1L and 1R, the CCD control signal for the line CCD 104 in the light receiving unit, the CCD clock signal and output signal, and the drive signals for the infrared LEDs 101A and 101B in the light projecting unit are mainly used. Are being exchanged.

  Here, a detailed configuration of the control / arithmetic unit 2 will be described with reference to FIG.

  FIG. 27 is a block diagram showing a detailed configuration of the control / arithmetic unit according to the first embodiment of the present invention.

  The CCD control signal is output from an arithmetic control circuit (CPU) 21 constituted by a one-chip microcomputer or the like, and shutter timing of the line CCD 104, data output control, and the like are performed.

  The arithmetic control circuit 21 operates in accordance with the clock signal from the clock generation circuit (CLK) 22. The clock signal for the CCD is transmitted from the clock generation circuit (CLK) 22 to the sensor units 1L and 1R, and arithmetic control is performed to perform various controls in synchronization with the line CCD 104 in each sensor unit. It is also input to the circuit 21.

  The LED drive signal for driving the infrared LEDs 101A and 101B of the light projecting unit is sent from the arithmetic control circuit 21 via the LED drive circuit (not shown) to the infrared LEDs 101A in the light projecting units of the corresponding sensor units 1L and 1R. And 101B.

  Detection signals from the line CCDs 104 in the light receiving portions of the sensor units 1L and 1R are input to the A / D converter 23 and converted into digital values under the control of the arithmetic control circuit 21. The converted digital value is stored in the memory 132 and used for calculating the angle of the pointing tool. Then, a coordinate value is calculated from the calculated angle, and is output to the external terminal via the serial interface 7 (for example, USB, IEEE1394, RS232C interface, etc.).

  When a pen is used as the pointing tool, the pen signal receiving unit 5 that receives the pen signal from the pen outputs a digital signal obtained by demodulating the pen signal. Thereafter, the signal is input to the sub CPU 24 serving as a pen signal detection circuit, the pen signal is analyzed, and the analysis result is output to the arithmetic control circuit 21.

<Detailed description regarding optical arrangement of sensor unit 1>
FIG. 28 is an explanatory diagram for explaining the optical arrangement of the coordinate input device according to the first embodiment of the present invention.

  In FIG. 28, the arrangement of the left sensor unit 1L will be particularly described. The right sensor unit 1R has the same characteristics except for the symmetrical relationship with the left sensor unit 1L with respect to the Y-axis in the drawing, and thus the description thereof is omitted.

  As described above, the sensor unit 1L has two sets of light projecting units and light receiving units (optical units L1 and L2), and their optical axes (optical symmetry axes, the light beam 151, and (Corresponding to the light beam 161) are arranged substantially parallel and separated by a predetermined distance d. Further, the sensor unit 1L is arranged such that its sensor surface is inclined by θs with respect to one side of the coordinate input effective area 3.

  Further, the light projecting range (or the detection angle range of the light receiving unit) of one light projecting unit in the sensor unit 1L is defined as a light beam 152 and a light beam 153, and the other is defined as a light beam 162 and a light beam 163.

  The sensor unit 1R has two sets of light projecting units and light receiving units (optical units R1 and R2).

  The effective visual field range of the two sets of optical units (light projecting unit and light receiving unit) defined by the light beam 152 and the light beam 153 or the light beam 162 and the light beam 163 is approximately 90 °. Of course, the range can be set to, for example, 100 °. However, setting and designing the effective visual field range to be larger may result in, for example, optical distortion of an optical component (for example, a lens) constituting the optical unit. This is disadvantageous in that the optical system is configured at a low cost.

  Accordingly, in order to obtain the pointing position information of the pointing tool that blocks the projected light at each light receiving unit, it is necessary to set the coordinate input effective area within the area defined by the light beam 152 and the light beam 163. This is a preferred form. Therefore, if the coordinate input effective area is set to the area 171 as shown in the figure, the light shielding position of the pointing tool (light shielding object) in the area 171 can be detected by the two sets of light receiving units in the sensor unit 1L. .

  However, by setting in this way, for example, the housing frame determined by the relationship between the housing 172 of the coordinate input device incorporating each component and the area 171 where the coordinates can be input becomes larger, and the coordinates are larger than the operable area. The subject that the magnitude | size of the whole input device will become large arises. In order to solve this problem, it is needless to say that the shape of the sensor unit 1L (1R) is reduced, and furthermore, two sets of optical units (light projecting unit and light receiving unit) defined by the light beam 151 and the light beam 161 are used. It is preferable to make the predetermined distance d of the part) smaller.

  In the coordinate input device according to the first embodiment, in order to make the housing frame determined by the coordinate input effective area 3 and the housing 172 as small as possible, one light receiving unit in the sensor unit 1L (1R) All the areas 3 are within the effective field of view. On the other hand, the other light receiving unit is set so that the region defined by the region 173 in the figure is outside the effective visual field.

  The distance d is determined by the projection component viewed from the direction of the pointing tool when the pointing tool is at the left or right end or upper end of the coordinate input effective area 3, that is, d * cos (θL−θs). It is comprised so that it may become substantially equal to the radius of.

  By doing so, in FIG. 28, the pointing tool behind is configured not to completely enter the region between the light beam 151 and the light beam 161 in the drawing.

<Coordinate calculation procedure>
In the first embodiment, for example, the light intensity distribution obtained from each of the optical units L1, L2, R2, and R1 in FIG. 28 is acquired. Then, the number of shadows and the position (angle) of the shadow obtained by each optical unit are calculated from this light intensity distribution. Then, four types of combinations obtained from the optical unit L1 / L2 constituting the sensor unit 1L and the optical unit R1 / R2 constituting the sensor unit 1R, that is, (L1, R1), (L1, R2), (L2 , R1) and (L2, R2) are selected in order.

  Next, in each combination, the coordinate candidate points are determined or the overlapping situation of the coordinate candidate points is determined, and an appropriate combination of the optical units is selected from them. Thereby, an actual input point is determined from so-called coordinate candidate points (so-called true / false determination), and finally two input coordinates are determined.

Hereinafter, the four combinations (L1, R1), (L1, R2), (L2, R1), and (L2, R2) are expressed as “LR optical unit combinations” or “LR combinations”.
Next, the coordinate calculation process in Embodiment 1 is demonstrated using FIG.

  FIG. 29 is a flowchart showing coordinate calculation processing executed by the coordinate input device according to the first embodiment of the present invention.

  First, in step S101, light intensity distribution data in each optical unit of the optical units L1, L2, R1, and R2 is acquired. Next, in step S102, the number of shadows (light-shielding shadows) detected by each optical unit and the position (angle) of the shadows are calculated from the acquired light intensity distribution data.

  Next, based on the “LR combination” and the number of shadows detected by each optical unit, the detection state of the number of shadows in each optical unit is determined. Based on the determination result, a coordinate candidate point determination routine (step S103 to step S114) for determining a coordinate candidate point used for coordinate calculation is executed.

  In particular, in the first embodiment, the following four types are considered as the detection state of the number of shadows in each optical unit. The combination of the number of shadows for (Ln, Rm) (n = 1, 2, m = 1, 2) is expressed as [XY] (X = 1, 2, Y = 1, 2).

  Detection state [1]: The number of shadows is [1-1] in all LR combinations.

  Detection state [2]: There are two or more LR combinations of [2-2].

  Detection state [3]: There is an LR combination of [2-2] and an LR combination of [2-1].

  Detection state [4]: There are two LR combinations of [2-1].

  In the first embodiment, the detection state of the number of shadows in each optical unit is determined (steps S103 to S105, step S108, and step S109). Next, coordinate calculation is performed by the coordinate calculation methods [1] to [4] defined in advance according to the determined detection state (steps S110 to S113). Then, the coordinate calculation result is output (step S114). On the other hand, if none of the above detection states is determined, it is determined that coordinate detection is impossible, and the process ends (step S106 or step S109).

  The details of each of the coordinate calculation methods [1] to [4] will be described below.

Coordinate calculation method [1] (in the case of step S110: detection state [1])
The case of the detection state [1] is a case where a single input is made. In this case, coordinate calculation can be executed with any LR combination. For example, in the optical unit combination of (L1, R1), coordinate calculation is executed by <coordinate calculation processing (1)> described later.

Coordinate calculation method [2] (in the case of step S111: detection state [2])
The detection state [2] means that there are two or more pairs [2-2] from among the LR combinations (L1, R1), (L1, R2), (L2, R1), and (L2, R2). It is.

  Two sets are selected from these, and the four coordinate candidate points obtained from each are compared.

  Here, as a specific example, the case where (L1, R1) and (L2, R1) are [2-2] will be described with reference to FIGS.

  In FIG. 30, P11, P12, P21, and P22 are determined from the combination of (L1, R1) based on <coordinate calculation processing (1)> described later. Similarly, in FIG. 31, P′11, P′12, P′21, and P′22 are determined from the combination of (L2, R1) based on <Coordinate calculation processing (2)> described later.

  Here, the values of the four coordinate candidate points obtained from the respective LR combinations are compared.

  Among them, the coordinate candidate points based on the actually input coordinates are the same in principle in both LR combinations. On the other hand, coordinates that are not based on the actually input coordinates (so-called coordinate candidate points as virtual images) are different in each combination due to the offset of the optical unit position.

  Therefore, by comparing the values of the four coordinate candidate points obtained from the respective LR combinations, it is possible to determine that the coordinate candidate point whose comparison result substantially matches is the true coordinate value of the two input points. .

  In the example of FIGS. 30 and 31, P11 and P22 are determined as two input points based on actual inputs.

Coordinate calculation method [3] (step S112: detection state [3])
The detection state [3] is a case where the LR combination [2-2] and the LR combination [2-1] exist.

  Here, as a specific example, the case where (L1, R2) is [2-2] and (L1, R1) is [2-1] will be described with reference to FIGS.

In FIG. 32, P11, P12, P21, and P22 are determined from the combination of (L1, R2) based on <coordinate calculation processing (2)> described later. Similarly, FIG. 33 determines PP1 and PP2 from the combination of (L1, R1) based on <coordinate calculation processing (1)> described later.
Here, among P11, P12, P21, and P22 in FIG. 32, one of (P11, P22) and (P12, P21), which is a coordinate candidate point relatively close to (PP1, PP2) in FIG. And determine them as a set of coordinate values of two input points.

  In the example of FIGS. 32 and 33, P12 and P21 are determined as two input points based on actual inputs.

Coordinate calculation method [4] (in the case of step S113: detection state [4])
The detection state [4] is a case where there are two LR combinations of [2-1].

  Here, as a specific example, the case where (L1, R1) and (L1, R2) are [2-1] will be described with reference to FIGS.

  In FIG. 34, the substantially central portions of both ends of one overlapping shadow detected from the optical unit R1 are approximately treated as one angle θR, and PP1 and PP2 are represented based on <coordinate calculation processing (2)>. decide. Alternatively, in FIG. 35, approximately the center portions at both ends of one overlapping shadow detected from the optical unit R2 are approximately treated as one angle θR, and PP ′ is based on <coordinate calculation process (3)>. 1. Determine PP′2.

  In general, as shown in FIG. 35, when the combination with the higher shadow overlap rate is employed, a better calculation result can be obtained in the case of such approximate calculation.

  The coordinate calculation result of one input point or two input points calculated by any one of the coordinate calculation methods [1] to [4] as described above is output to the external terminal via the serial interface 7, and the image display device Displayed on the output device as a cursor movement or locus.

  Next, details of the contents of the coordinate calculation processes (1) to (3) will be described.

<Coordinate calculation process (1)>
Here, a coordinate calculation process (1) for calculating coordinates by a combination of the optical units L1 and R1 will be described with reference to FIG.

  In the sensor units 1L and 1R of FIG. 36, the left and right optical units with respect to the coordinate input effective area 3 are optical units (L1, R1). The left and right inner optical units are optical units (L2, R2).

  The angle data obtained from each optical unit is defined so that the Y axis downward direction is 0 ° when viewed from the corresponding sensor unit, and the angle increases inward and in the left and right target directions. In addition, the coordinate positions where each optical unit exists are P (L1), P (L2), P (R1), and P (R2).

  For example, when calculating coordinates based on the angle data obtained from the optical units L1 and R1, the following functions Xt and Yt are used to determine the X and Y directions as shown in the figure with the point O as the origin. Define.

Xt (θL-45, θR-45)
= (tan (θL-45) -tan (θR-45)) / [2 * (1-tan (θL-45) * tan (θR-45))] (120)
Yt (θL-45, B-45)
= (-1) * [(1-tan (θL-45)) * (1-tan (θR-45))
/(2*(1-tan(θL-45)*tan(θR-45)))-0.5] (121)
When defined in this way, the coordinates of the point P (X, Y) when the point O in FIG.
X = DLR * Xt (θL-45, θR-45) (122)
Y = DLR * Yt (θL-45, θR-45) (123)
It becomes.

<Coordinate calculation process (2)>
Here, a coordinate calculation process (2) for calculating coordinates by a combination of the optical units L2 and R1 will be described with reference to FIG.

  In FIG. 37, the pointing position of the pointing tool is P ′. Further, an intersection of the straight line P (L1) -P (R1) and the straight line P (L2) -P 'is defined as S'.

In FIG. 37, the calculation of the coordinates of P ′ from the positional relationship between the three points S ′, P (R1), and O ′ is performed from the three points P (L1), P (R1), and O to P in FIG. Equivalent to calculating coordinates. Here, the vector O′P ′ is expressed as O ′ → P ′, the X component is expressed as (O ′ → P ′) x, the Y component is expressed as (O ′ → P ′) y, and the equations (120) and (121) are expressed. )
(O '→ P') x = (DLR-ΔD) * Xt (θL-45, θR-45) (130)
(O '→ P') y = (DLR-ΔD) * Yt (θL-45, θR-45) (131)
It becomes.

Here, from FIG. 37, ΔD = Sx + Sy * tan (θL) (132)
However, Sx = d * cos (θs), Sy = d * sin (θs) (133)
Furthermore, as apparent from FIG.
(O → O ') x = ΔD / 2 (134)
(O → O ') y = (-1) * ΔD / 2 (135)
It becomes. Thus, the coordinates of P ′ with the point O as the origin can be calculated as the X component and the Y component of (O → P ′) = (O → O ′) + (O → P ′).

  Here, similarly, when the coordinates are calculated by the combination of the optical unit L1 and the optical unit R2, the calculation can be similarly performed by changing only the above-mentioned X component.

<Coordinate calculation process (3)>
Here, a coordinate calculation process (3) for calculating coordinates by a combination of the optical units L2 and R2 will be described with reference to FIG.

In FIG. 38, calculating the coordinates of P ″ from the positional relationship of the three points P (L2), P (R2), and O ″ is shown in FIG. 36 as three points P (L1), P (R1), It is equivalent to calculating the coordinates of P from O. Here, the vector O ″ P ″ is expressed as O ″ → P ″, the X component is expressed as (O ″ → P ″) x, and the Y component is expressed as (O ″ → P ″) y. Using the equations (120) and (121),
(O '' → P '') x = (DLR-2 * Sx) * Xt (θL-45, θR-45) (141)
(O '' → P '') y = (DLR-2 * Sx) * Yt (θL-45, θR-45) (142)
It becomes. As is clear from FIG.
(O → O ″) x = 0 (143)
(O → O ″) y = (-1) * (Sx + Sy) (144)
It becomes.

  As a result, the coordinates of P ″ with the point O as the origin can be calculated as the X and Y components of (O → P ″) = (O → O ″) + (O → P ″). it can.

  As described above, in the first embodiment, coordinates can be calculated for all LR combinations.

  As described above, according to the first embodiment, the retroreflecting unit arranged around the coordinate input effective area is configured to satisfy the above-described feature condition and the expressions (1) and (2). This prevents a shadow detected by each sensor unit with the same input from being detected with a difference in level (light shielding ratio) in each sensor unit. In addition, detection can always be performed at substantially the same level (light shielding ratio).

  Accordingly, it is possible to prevent the input coordinates from being missed at the time of a single input, and to prevent an erroneous number of input coordinates from being detected by detecting wrong coordinates different from the input coordinates at the time of a plurality of inputs. In particular, when the pointing tool enters and exits the light-shielding input area with input, it is possible to avoid the above-mentioned problem that the frequency of occurrence is high and to realize stable coordinate input.

<Embodiment 2>
In the second embodiment, a configuration in which a sensor unit 1C is newly added as shown in FIG. 39 to the configuration shown in FIG. 2A of the first embodiment will be described.

  FIG. 39 shows a case where a plurality of inputs are performed at points P12 and P21.

  In this case, as shown in FIG. 40A, a shadow is detected at the positions of θL1 and θL2 in the sensor unit 1L. In addition, as shown in FIG. 40B, shadows are detected at the positions of θR1 and θR2 in the sensor unit 1R. Further, as shown in FIG. 40C, shadows are detected at the positions of θC1 and θC4 in the sensor unit 1C. Based on these three sets of angle data, four coordinate candidate points P11, P12, P21 and P22 are calculated. Then, from these coordinate candidate points, by determining whether the coordinates are true by some means, for example, it is determined that P11 and P22 are real images and P12 and P21 are virtual images, and the coordinate input points are determined. Become.

  The sensor unit 1C shown in FIG. 39 has substantially the same configuration as the sensor units 1L and 1R, but the structure of the built-in optical unit (light receiving unit and light projecting unit) is different. Specifically, the visual field range in the coordinate input plane direction of the sensor units 1L and 1R is approximately 90 degrees, whereas the visual field range of the sensor unit 1C is approximately 180 degrees.

  The most important thing is that the sensor units 1L, 1R, and 1C and the retroreflective portion arranged around the coordinate input effective area 3 satisfy the same conditions as the sensor units 1L and 1R in the first embodiment. It is. That is, the condition that the three-dimensional shading detection areas related to both are substantially the same is satisfied.

  Furthermore, in the second embodiment, the three-dimensional shading detection area related to the sensor unit 1C includes the common three-dimensional shading detection area of the sensor units 1L and 1R. In this case, it is not necessary to match the three-dimensional shading detection area relating to the sensor unit 1C and the three-dimensional shading detection areas relating to the sensor units 1L and 1R, and the former only includes the latter.

  With this configuration, when input is performed by the pointing tool, the depth (light shielding ratio) of the light shielding shadow observed by each of the sensor units 1L and 1R is observed as substantially the same value. Thus, when two coordinates are input, the coordinate candidate points can be detected correctly without being erroneously detected. Further, since the three-dimensional shading detection area of the sensor unit 1C includes that of the sensor units 1L and 1R, the shadow of the coordinate candidate point is always observed by the sensor unit 1C. Then, true coordinates can be selected from the coordinate candidate points according to the angle corresponding to the observed shadow.

  Therefore, correct coordinate detection can always be performed from the relationship between the sensor units 1L, 1R, and 1C. In particular, stable coordinate calculation can be performed without erroneously recognizing a light-shielding shadow even when the pointing tool enters or exits the input of the coordinate input effective area.

  In the second embodiment, the coordinate candidate points are detected by the sensor units 1L and 1R, and the actual input point is determined from the coordinate candidate points based on the positional relationship with the shadow detected by the sensor unit 1C (so-called true / false determination). Finally, two input coordinates are determined.

  For example, in FIG. 39, four coordinate candidate points P11, P12, P21, and P22 are observed by the sensor units 1L and 1R. Among these coordinate candidate points, the coordinate candidate points observed in the predetermined direction by the sensor unit 1C are the coordinate candidate points of the actual input points, and these are finally output as two input coordinates. . In particular, in the case of FIG. 39, only the shadows of θC1 and θC4 are observed in the sensor unit 1C, so P11 and P22 are the coordinates of the actual input points.

  Hereinafter, the coordinate calculation process according to the second embodiment will be described with reference to FIG.

  FIG. 41 is a flowchart showing coordinate calculation processing executed by the coordinate input device according to the second embodiment of the present invention.

  First, in step S201, light intensity distribution data in the sensor units 1L, 1R, and 1C is acquired. Next, the number of shadows (light-shielding shadows) detected by each sensor unit and the position (angle) of the shadows are calculated from the acquired light intensity distribution data.

  Next, based on the number of shadows detected by each sensor unit, a detection state of the number of shadows in each sensor unit is determined, and based on the determination result, a coordinate candidate point determination routine for determining coordinate candidate points used for coordinate calculation (Steps S202 to S208) are executed.

  In particular, in the second embodiment, the following three types are considered as the detection state of the number of shadows in each sensor unit. In the second embodiment, the combination of the number of shadows for the sensor unit 1L and the sensor unit 1R is expressed as [XY] (X = 1, 2, Y = 1, 2).

  Detection state [1]: The number of shadows determined by the sensor unit 1L and the sensor unit 1R is [1-1].

  Detection state [2]: The number of shadows determined by the sensor unit 1L and the sensor unit 1R is [2-2].

  Detection state [3]: The number of shadows determined by the sensor unit 1L and the sensor unit 1R is [2-1].

  In the second embodiment, the detection state of the number of shadows in the sensor unit 1L and the sensor unit 1R is determined (steps S202 to S204). Next, coordinate calculation is performed by the coordinate calculation methods [5a] to [5c] defined in advance according to the determined detection state (steps S205 to S207). Then, the coordinate calculation result is output (step S208). On the other hand, if none of the above detection states is determined, it is determined that coordinate detection is impossible, and the process ends (step S209).

  Hereinafter, the details of each of the coordinate calculation methods [5a] to [5c] will be described.

Coordinate calculation method [5a] (in the case of step S205: detection state [1])
The case of the detection state [1] is a case where a single input is made. In this case, the coordinate calculation is executed by the <coordinate calculation process (1)> described in the first embodiment.

Coordinate calculation method [5b] (in the case of step S206: detection state [2])
The case of the detection state [2] is a case where the sensor units 1L and 1R are [2-2].

  In this case, the coordinate values of the obtained four coordinate candidate points are calculated by the <coordinate calculation process (1)> described in the first embodiment. Further, the angle when each coordinate candidate point is observed from the sensor unit 1C is calculated in advance.

  Among these, what is substantially positioned with the shadow angle actually observed by the sensor unit 1C is adopted as two input coordinates.

Coordinate calculation method [5c] (in the case of step S206: detection state [3])
The case of the detection state [3] is a case where the sensor units 1L and 1R are [2-1].

  In this case, it is approximated that there are two input coordinates on the substantially central angle at both ends of the overlapping shadow, and each of them is combined with the other two shadows in the <coordinate calculation described in the first embodiment. Coordinates are determined based on processing (1)>. The light intensity distribution data detected by the sensor unit 1C is not used for true / false determination but is used for verification to improve the accuracy of the determined coordinate value.

  As described above, according to the second embodiment, in addition to the effects described in the first embodiment, by configuring the sensor unit 1C, it is possible to realize the true / false determination related to the coordinate calculation more efficiently and accurately. Can do.

  Although the embodiment has been described in detail above, the present invention can take an embodiment as, for example, a system, apparatus, method, program, or storage medium. Specifically, the present invention may be applied to a system composed of a plurality of devices, or may be applied to an apparatus composed of a single device.

  In the present invention, a software program (in the embodiment, a program corresponding to the flowchart shown in the drawing) that realizes the functions of the above-described embodiments is directly or remotely supplied to a system or apparatus. This includes the case where the system or the computer of the apparatus is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, or the like.

  Examples of the recording medium for supplying the program include a floppy (registered trademark) disk, a hard disk, and an optical disk. Further, as a recording medium, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD-R), etc. is there.

  As another program supply method, a browser on a client computer is used to connect to an Internet home page. Then, the computer program of the present invention itself or a compressed file including an automatic installation function can be downloaded from a homepage of the connection destination to a recording medium such as a hard disk. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, the present invention includes a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. Let It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  Further, the functions of the above-described embodiments are realized by the computer executing the read program. Further, based on the instructions of the program, an OS or the like running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments can be realized by the processing.

  Further, the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing based on the instructions of the program, and the functions of the above-described embodiments are realized by the processing.

It is a figure which shows the external appearance structure of the coordinate input device of Embodiment 1 of this invention. It is a figure for demonstrating the shape of the light-shielding detection area | region in the coordinate input device of Embodiment 1 of this invention. It is a figure which shows the external appearance structure of the coordinate input device of Embodiment 1 of this invention. It is a figure for demonstrating the shape of the light-shielding detection area | region in the coordinate input device of Embodiment 1 of this invention. It is a figure for demonstrating the subject in this invention. It is a figure for demonstrating the concept of the light-shielding detection area | region in this invention. It is a figure for demonstrating the three-dimensional shading detection area | region of each sensor unit in this invention. It is a figure for demonstrating the three-dimensional shading detection area | region of each sensor unit in this invention. It is a figure for demonstrating the "pen-tip height vs. light-shielding rate" characteristic in this invention. It is a figure for demonstrating the "pen-tip height vs. light-shielding rate" characteristic in this invention. It is a figure for demonstrating the single input operation in this invention. It is a figure which shows the light intensity distribution obtained from the sensor unit in input operation of FIG. It is a figure which shows the light intensity distribution obtained from the sensor unit in input operation of FIG. It is a figure for demonstrating the multiple input operation in this invention. It is a figure which shows the light intensity distribution obtained from the sensor unit in input operation of FIG. It is a figure for demonstrating the example of the erroneous detection in this invention. It is a figure which shows the light intensity distribution obtained from the sensor unit in input operation of FIG. It is a figure for demonstrating the example of the erroneous detection in this invention. It is a figure which shows the light intensity distribution obtained from the sensor unit in input operation of FIG. It is a figure for demonstrating the example of the erroneous detection in this invention. It is a figure for demonstrating the example of the erroneous detection in this invention. It is a figure for demonstrating the concept of the light-shielding detection area | region of Embodiment 1 of this invention. It is a figure for demonstrating the concept of the light-shielding detection area | region of Embodiment 1 of this invention. It is a figure for demonstrating the concept of the light-shielding detection area | region of Embodiment 1 of this invention. It is a figure for demonstrating the concept of the light-shielding detection area | region of Embodiment 1 of this invention. It is a figure for demonstrating the concept of the light-shielding detection area | region of Embodiment 1 of this invention. It is a figure for demonstrating the concept of the light-shielding detection area | region of Embodiment 1 of this invention. It is a figure for demonstrating the concept of the light-shielding detection area | region of Embodiment 1 of this invention. It is a figure for demonstrating the concept of the light-shielding detection area | region of Embodiment 1 of this invention. It is a figure for demonstrating the "pen-tip height vs. light-shielding rate" characteristic in this invention. It is a figure for demonstrating the three-dimensional shading detection area | region of each sensor unit in this invention. It is a figure for demonstrating the three-dimensional shading detection area | region of each sensor unit in this invention. It is a figure which shows the example of arrangement | positioning of the sensor unit of the coordinate input device of Embodiment 1 of this invention. It is a figure for demonstrating the coordinate detection principle of Embodiment 1 of this invention. It is a figure which shows the detailed structure of the sensor unit of Embodiment 1 of this invention. It is an optical arrangement | positioning figure of the sensor unit of Embodiment 1 of this invention. It is an optical arrangement | positioning figure of the sensor unit of Embodiment 1 of this invention. It is an optical arrangement | positioning figure of the sensor unit of Embodiment 1 of this invention. It is a block diagram which shows the detailed structure of the control / arithmetic unit of Embodiment 1 of this invention. It is explanatory drawing for demonstrating the optical arrangement | positioning of the coordinate input device of Embodiment 1 of this invention. It is a flowchart which shows the coordinate calculation process which the coordinate input device of Embodiment 1 of this invention performs. It is a figure for demonstrating the coordinate calculation method of Embodiment 1 of this invention. It is a figure for demonstrating the coordinate calculation method of Embodiment 1 of this invention. It is a figure for demonstrating the coordinate calculation method of Embodiment 1 of this invention. It is a figure for demonstrating the coordinate calculation method of Embodiment 1 of this invention. It is a figure for demonstrating the coordinate calculation method of Embodiment 1 of this invention. It is a figure for demonstrating the coordinate calculation method of Embodiment 1 of this invention. It is a figure for demonstrating the coordinate calculation process of Embodiment 1 of this invention. It is a figure for demonstrating the coordinate calculation process of Embodiment 1 of this invention. It is a figure for demonstrating the coordinate calculation process of Embodiment 1 of this invention. It is a figure which shows the structure of the coordinate input device of Embodiment 2 of this invention. It is a figure which shows the light intensity distribution obtained from the sensor unit in input operation of FIG. It is a flowchart which shows the coordinate calculation process which the coordinate input device of Embodiment 2 of this invention performs.

Explanation of symbols

1L, 1R Sensor unit 2 Arithmetic / control unit 3 Coordinate input effective area 4a-4c Retroreflecting unit 5 Pen signal receiving unit

Claims (7)

A coordinate input device for detecting a designated position on a coordinate input area,
A plurality of sensor means comprising: a light projecting unit that projects light to the coordinate input region; and a light receiving unit that receives incoming light;
A plurality of retroreflective means for recursively reflecting incident light;
Calculation means for calculating the coordinates of the indicated position of the instruction means based on the light amount distribution obtained from each of the plurality of sensor means by an instruction by the instruction means;
The three-dimensional shading detection area related to the plurality of sensor means has a common three-dimensional solid shape corresponding to the coordinate input area, and the three-dimensional shading detection area is a rate of change in observed light intensity. Is defined as a three-dimensional region in which a change in position in the height direction of the indicating means can be detected ,
Of the plurality of sensor means, one sensor means faces and the other sensor means does not face the shape of the retroreflective means,
The other sensor means;
A mirror image of the other sensor means with respect to the coordinate input area;
The retroreflective means facing the other sensor means;
A shape defined by a mirror image of the retroreflective means facing the coordinate input area of the other sensor means;
The coordinate input device according to claim 1 , wherein the three-dimensional solid shape is defined as a three-dimensional solid corresponding to the shape of a cross section along the retroreflective means opposed to the one sensor means . The upper end of the first light-shielding detection window, which is a real image, is Opt1, the lower end is Opt2,
The upper end of the second light-shielding detection window that is a mirror image is Opt4 ′, the lower end is Opt3 ′,
The position of the first light shielding detection window on the coordinate input area is Opt0,
Ref1 is the upper end of the real image of the retroreflective means facing, Ref2 is the lower end,
The upper end of the mirror image of the retroreflective means is Ref1 ′, the lower end is Ref2 ′,
The position of the retroreflective means on the coordinate input area is Ref0,
The intersection of the line segment Ref2-Opt3 ′ and the line segment Ref0-Opt0 is defined as Q1,
The intersection of the line segment Ref1′-Opt2 and the line segment Ref0-Opt0 is defined as Q2,
The intersection of the line segment Ref1-Opt3 and the line segment Ref2-Opt1 ′ is defined as Q3,
The intersection of the line segment Ref2-Opt0 and the line segment Ref0_Opt2 is defined as Q4,
If
The upper side of the cross-section is at a position lower than the line segment Ref1-Opt1 and higher than the line segment Ref1-Q3-Opt1;
The coordinate input device according to claim 1, wherein the lower side of the cross section is located at a position lower than the line segment Ref2-Q4-Opt2 and higher than the line segment Ref2-Q1-Q2-Opt2. The Opt1 is selected from the higher one of the upper end of the light projecting window that is the light projecting range of the light projecting unit of the sensor means and the upper end of the light receiving window that is the light receiving range of the light receiving unit,
The Opt 2 is a higher one of the lower end of the light projecting window that is the light projecting range of the light projecting unit of the sensor means and the lower end of the light receiving window that is the light receiving range of the light receiving unit,
The Opt4 ′ is a mirror image of the coordinate input region of the lower selection result of the lower end of the light projecting window that is the light projecting range of the light projecting unit of the sensor means and the lower end of the light receiving window that is the light receiving range of the light receiving unit. Yes,
The Opt3 ′ is a mirror image of the coordinate input region of the selection result of the lower of the upper end of the light projecting window that is the light projecting range of the light projecting unit of the sensor means and the upper end of the light receiving window that is the light receiving range of the light receiving unit. The coordinate input device according to claim 2 , wherein: The plurality of sensor means are provided at both ends of one side of the coordinate input area,
The plurality of retroreflective means are provided on a side excluding the one side of the coordinate input area,
Of the plurality of sensor means , one of the sensor means faces and the other sensor means does not face the shape of the retroreflective means , and the other sensor means has an extension of one end of the retroreflective means. The end side of the other retroreflective means such that the light-shielding detection windows coincide with each other coincides with the end side of the retroreflective means opposed in common by the plurality of sensor means, and at least the lower side The coordinate input device according to claim 1, wherein is a bow shape. The light-shielding detection window has an upper end at the upper end of a light projection window that is a portion that contributes to effective light projection in the sensor means, and a higher end of the light reception window that is a portion that effectively contributes to light reception, and The coordinate input device according to claim 4 , wherein the coordinate input device is a part of a range determined by setting a lower end of the light projection window and a lower end of the light receiving window as a lower end. The coordinate input device according to claim 1, wherein the sensor unit includes one optical unit including the light projecting unit and the light receiving unit. The coordinate input device according to claim 1, wherein the sensor unit includes two optical units including the light projecting unit and the light receiving unit.

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