JP4590296B2 - 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 disposed at a corner end of the coordinate input area and a light receiving unit that receives the light are used in the coordinate input area. Discloses a configuration in which an angle between a light shielding unit and a light shielding unit that shields light such as a finger is detected, and an instruction position of the shielding material 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 combinations of the angles of the respective sensors. Furthermore, a technique for discriminating the actually input coordinates from the 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. In addition to the first and second sensors installed apart from each other, the first and second sensors are separated from each other by a distance sufficient to accurately calculate the coordinates indicated in the input area from the first and second sensors. A third sensor is provided at a position between the 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, there is a possibility that a shadow to be detected at a predetermined position is not detected, that is, 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 for detecting a designated position on a coordinate input area,
A plurality of sensor means provided around the coordinate input area, comprising: a light projecting unit that projects light to the coordinate input area; and a light receiving unit that receives incoming light;
A plurality of retroreflective means provided around the coordinate input region and 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;
A light shielding detection window in which the upper side of the member constituting the retroreflective means forms a common first plane, and the lower side of the member forms a common second plane, and is a light shielding detection range of the sensor means The sensor means and the retroreflective means are arranged such that the upper end portion of the light shielding detection window is located on the first plane and the lower end portion of the light shielding detection window is located on the second plane,
The three-dimensional shading detection area related to the plurality of sensor means is a space sandwiched between the first plane and the second plane, and has a common three-dimensional solid shape corresponding to the coordinate input area. .

In a preferred embodiment, the three-dimensional shielding detection region, the shape of the retroreflector facing the sensor means is a three-dimensional solid defined by the light shielding sensing window.

  Preferably, the light shielding detection window is either a lower end of a light projecting window that is a light projecting range of a light projecting unit provided in the sensor means or a lower end of a light receiving window that is a light receiving range of a light receiving unit provided in the sensor means. The higher position is defined as the lower end, and the upper end of the light projecting window or the upper end of the light receiving window is defined as the upper end.

  Preferably, the sensor means includes a retroreflective means related to the sensor means with respect to a direction perpendicular to the coordinate input area, and the visual field range of the light receiving part is the sensor. Includes retroreflective means associated with the means.

  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 4a to 4c denote retroreflective portions having retroreflective surfaces for reflecting incident light in the direction of arrival, which are arranged on the three outer sides of the coordinate input effective area 3 as shown in the figure, and are approximately 90 ° from the respective sensor units 1L and 1R. The light projected in the range is retroreflected 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. The light projected from the light projecting part is blocked (light-shielding part), and the light of the light-shielding part (recursive reflection) is received at the light-receiving parts of the optical units L1 and L2 and the optical units R1 and R2 in the sensor units 1L and 1R, respectively. As a result, it is possible 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). Then, 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, and the calculated direction (angle), sensor unit 1L (optical units L1 and L2) and 1R ( From the distance information between the optical units R1 and R2), the light shielding position of the pointing tool on the coordinate input effective area 3 is geometrically calculated, and the interface 7 is connected to an external terminal such as a host computer connected to the display device. The coordinate value is output via USB (for example, USB, IEEE1394, 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, the direction perpendicular to the coordinate input effective area 3 is defined as the height direction (Z direction), and the case close to the coordinate input effective area 3 is expressed as “down” and the case distant from the coordinate input effective area 3 is expressed as “upper”. Further, in FIG. 1A, the sensor units 1L (optical units L1 and L2) and 1R (optical units R1 and R2) are areas where light shielding is effectively detected (light shielding range), that is, the actual existence of a light shielding detection window. Expressed. In particular, the width in the height direction means the width of the upper and lower ends of the light shielding detection window.

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

  In particular, in the first embodiment, as shown in FIG. 1B, the upper sides of the retroreflective portions 4a to 4c and the effective upper ends of the sensor units 1L and 1R form substantially the same plane S_top. Further, the lower sides of the retroreflective portions 4a to 4c and the effective lower ends of the sensor units 1L and 1R constitute substantially the same plane S_bottom.

  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.

  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, in FIGS. 3 to 23, the case of the monocular configuration of FIGS. 2A and 2B will be described as an example, but the compound eye (two eyes) of FIGS. 1A and 1B will be described. The present invention can also be applied to a configuration or a compound eye configuration 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. In other words, in the case of a monocular configuration, the sensor unit and one optical unit incorporated therein can be described with the same view. However, in the case of a compound eye configuration, each of the plurality of optical units constituting the sensor unit is illustrated. Note that the description of 3 to 23 applies.

<Explanation of issues>
Here, the problem in the present invention will be described again 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. And a coordinate input device that is assumed to be as parallel (collimated) as possible with respect to light projection / light reception.

  Here, it is assumed that the light projection / light reception is completely parallel to the thickness direction (here, the thickness direction means a direction (Z direction) perpendicular to the coordinate input surface (coordinate input effective area 3)). If the retroreflective part is set to have a shape and size so as to include the light directivity range (field range) and the light reception directivity range (field range) in the thickness direction, a three-dimensional shading detection region It can be said that this is determined only by the light path of light projection or light reception, regardless of the shape of the retroreflective portion.

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

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

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

  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.

  In fact, when such a light-shielding coordinate input device is incorporated into or overlaid on a display device, this arrangement is often used.

  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 feeling uncomfortable. For this reason, the elongated retroreflective portions are accommodated in the black frame of the display screen, that is, arranged close to the display surface.

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

  First, regarding the sensor unit 1L, the light projected from the sensor unit 1L is retroreflected only at the retroreflective portions 4a and 4c and returns to the sensor unit 1L again. Here, as long as the light projecting / receiving optical system of the sensor unit 1L is not substantially collimated along the coordinate input surface, a three-dimensional shading detection region as shown in FIG. 4 is practically formed. It will be.

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

  Here, as is apparent from FIGS. 4 and 5, the three-dimensional light-shielding region related to the sensor unit 1L and the three-dimensional light-shielding region related 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 point C in FIG.

  At point C, as shown in FIG. 4, the three-dimensional shading detection area related to the sensor unit 1L is close to the sensor unit 1L, and therefore is at a relatively high position (position away from the coordinate input surface).

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

  Here, the “pen tip height vs. light blocking ratio” characteristic as shown in FIG. 6 is considered. In FIG. 6, the horizontal axis is 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 ratio of 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 FIG.

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

  When the pointing tool is inserted at the point C, the broken line is a locus indicating the displacement of the light shielding rate related to the sensor unit 1L, and the solid line is related to the sensor unit 1R.

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

  On the other hand, since the three-dimensional shading detection region related to the sensor unit 1R is at a low position, the part where the solid line locus shown in FIG.

  And it can be said that the part which changes greatly is a part which passes the three-dimensional shading detection area | region of each sensor unit of the sensor units 1L and 1R.

  3 to 5, in the vicinity of the point C, the three-dimensional shading detection area related to the sensor unit 1L is higher than the three-dimensional shading detection area related to the sensor unit 1R. In FIG. 6, 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, 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. 6, and each of the sensor units 1L and 1R is Assume that it is determined that there is a shadow when the intensity of the shadow to be detected, that is, the light shielding rate exceeds a 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.

  This is a big problem especially when a plurality of inputs are performed.

  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 point C, 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. As this erroneous detection pattern (1), as shown in FIG. 12, when a plurality of inputs are made at point P12 (corresponding to point C in FIG. 7) and point P21, and the height H of the indicator at each point Consider the case of Hth_R ≦ H ≦ Hth_L shown in FIG.

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

  In this case, in fact, although two inputs are made at the positions of point C (P12) and P21, only θR1 is detected and θR2 is not detected from the sensor unit 1R (ie, the 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, as shown in FIG. 14, there are a plurality of false detection patterns (2) at point P12 (corresponding to point C in FIG. 7) and point P21 (point C ′ approximately symmetrical with respect to point C). When the input is performed and the height H of the pointing tool at the position of the point C is Hth_R ≦ H ≦ Hth_L shown in FIG. 6, the height H of the pointing tool at the position of the point C ′ is as shown in FIG. Consider the case of Hth_L (C ′) ≦ H (C ′) ≦ Hth_R (C ′) with the relationship between the sensor units 1L and 1R being exchanged.

  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 they are input to C (P12) and C ′ (P21), the intersections of the angles θL1 and θR1 actually detected, that is, P11 in FIG. It is 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 point C), the shadow that should be originally detected by both the sensor units 1L and 1R Since the three-dimensional shading detection areas are different from each other, the coordinate input points cannot be detected by a correct combination from the coordinate candidate points detected at the time of a plurality of inputs.

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

  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. 4 and 5 the same space.

  First, it is conceivable that, for example, the cross section of the optical path in the vicinity of the left side of the sensor unit 1L and the shape of the retroreflective portion 4b related to the sensor unit 1R are made substantially the same. Similarly, the cross section of the optical path in the vicinity of the right side of the sensor unit 1R and the shape of the retroreflective portion 4a related to the sensor unit 1L are substantially the same.

  In this way, a three-dimensional shading detection region as shown in FIG. 2A can be formed, and this region is common to the sensor units 1L and 1R. That is, it becomes a common three-dimensional solid shape corresponding to the coordinate input effective area.

  In FIG. 2A, the retroreflective portion 4c is rectangular, the retroreflective portions 4a and 4b are the same trapezoid, and the sensor units 1L and 1R are symmetrical. 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.

<Effective sensor unit shading detection window>
As described above, in FIG. 2A, the sensor units 1L and 1R is the shading including light emitting / receiving of light as actual existence of the light shielding detection window for detecting effectively, in particular, it makes sense in the height direction It is expressed as follows. That is, the thickness of the semi-cylindrical shape of the sensor units 1L and 1R is the size of the effective light shielding detection window defined in the height direction.

  Hereinafter, a cross section of the light shielding detection region (light shielding detection window) will be described with reference to FIGS.

  16 to 19, the effective light projecting unit 102 constituting the sensor unit is represented by a lattice pattern, and the effective light receiving unit 106 is represented by an oblique stripe pattern. Each of the widths shown in the drawing represents the width of light emission (effective window width) and the width of light reception (effective window width). Here, the description will be given focusing on the sensor unit 1L.

  The sensor unit is composed of a light projecting unit and a light receiving unit, which are ideal if they are originally arranged at the same position, but in reality, this is often not possible due to limitations such as cost and accuracy. Therefore, the following arrangement configuration is actually employed.

(1) When the light projecting unit 102 is disposed on the light receiving unit 106 (FIG. 16)
(2) When the light receiving unit 106 is disposed on the light projecting unit 102 (FIG. 17)
(3-a) if the light projecting portion 102 and the light receiving portion 106 is disposed side by side, towards the light projecting portion 102 is large (Fig. 18)
(3-b) when the light projecting portion 102 and the light receiving portion 106 is disposed side by side, greater in the light receiving portion 106 (FIG. 19)
(4) Using a half mirror, the light projecting unit and the light receiving unit may be equivalently arranged at the same position.

  In the present invention, since only the height direction from the coordinate input surface is a problem, the arrangement configurations of (3) and (4) are handled in the same way.

  Next, how the light shielding detection window of the sensor unit is defined will be described.

  16 to 19, H_led_1 is not the actual size of the light projecting unit, but the height of the upper end of the eye of the effective light projecting unit, and H_led_2 is the height of the lower end. H_sense_1 is not the actual size of the light receiving portion, but the height of the upper end of the range in which an image is effectively formed on the photoelectric conversion portion of the sensor in the light receiving portion, and H_sense_2 is the height of the lower end.

  H_ref_1 is the effective upper end height of the retroreflective portion 4a facing the sensor unit. H_ref_2 is an effective lower end height of the retroreflective portion 4a facing the sensor unit.

  According to the insertion of the pointing tool, the position where the shadow first appears (distance between the pointing tool and the coordinate input surface) is H_A, and the position where the shadow depth (shading rate) reaches approximately 100% (the pointing tool and the coordinate input surface) ) Is indicated by H_B.

  Further, as an important point, in the thickness direction (direction perpendicular to the coordinate input surface), the visual field range of the light projecting unit is wider than and includes the retroreflective areas H_ref_1 to H_ref_2. Similarly, the visual field range of the light receiving unit is wider than and includes the retroreflective regions H_ref_1 to H_ref_2.

  16 to 19, the effective light path of the light projecting unit is an area sandwiched between line_led_1 and line_led_2, that is, the light projection window is defined by H_led_1 and H_led_2. Similarly, the effective optical path of the light receiving unit is a region sandwiched between line_sens_1 and line_sens_2, that is, the light receiving window is defined by H_sense_1 and H_sense_2.

  In the case of the configuration of the sensor unit in FIG. 16, when the pointing tool approaches the position of line_led_1, the effective light path of the light projecting unit is blocked, and here, the shadow of the light shielding is observed for the first time. Furthermore, when the pointing tool reaches the position of line_led_2, the effective light path of the light projecting unit is blocked by approximately 100%. Therefore, even if the portion below line_led_2 is left here, that is, even if the light receiving portion is not completely blocked, the shadow shading rate reaches approximately 100%.

  Therefore, the light blocking detection region is between line_led_1 and line_led_2. That is, the light shielding detection window of the sensor unit has an upper end of H_led_1 and a lower end of H_led_2. It should be noted that H_led_2 and H_sens_1 are the same even if their order is changed.

  Next, in the case of the configuration of the sensor unit in FIG. 17, when the pointing tool approaches the position of line_sens_1, the effective optical path of the light receiving unit is blocked. Furthermore, when the pointing tool reaches the position of line_sens_2, the effective light path of the light receiving unit is blocked by approximately 100%. Therefore, even if the portion below line_sens_2 is left here, that is, the light shielding ratio of the shadow reaches approximately 100% even if the light projecting portion is not completely blocked.

  Accordingly, the light shielding detection region is between line_sens_1 and line_sens_2. That is, the light shielding detection window of the sensor unit has an upper end of H__sens_1 and a lower end of H_sens_2. Note that H_sens_2 and H_led_1 are the same even if their order is changed.

  Next, in the case of the configuration of the sensor unit in FIG. 18, when the pointing tool approaches the position of line_led_1, the effective light path of the light projecting unit is blocked, and here, the shadow of the light shielding is observed for the first time. Further, when the pointing tool reaches the position of line_sens_2, this time, the effective optical path of the light receiving unit is blocked by approximately 100%. Therefore, even if the portion below line_sens_2 is left here, that is, the light shielding ratio of the shadow reaches approximately 100% even if the light projecting portion is not completely blocked.

  Therefore, the light-shielding detection region is between line_led_1 and line_sens_2. That is, the light shielding detection window of the sensor unit has an upper end H_led_1 and a lower end H_sens_2.

  Next, in the case of the configuration of the sensor unit in FIG. 19, when the pointing tool approaches the position of line_sens_ 1, the effective optical path of the light receiving unit is blocked. Further, when the pointing tool reaches the position of line_led_2, this time, the effective light path of the light projecting unit is blocked by approximately 100%. Therefore, even if the portion below line_led_2 is left here, that is, even if the light receiving portion is not completely blocked, the shadow shading rate reaches approximately 100%.

  Accordingly, the light blocking detection region is between line_sens_1 and line_led_2. That is, the light shielding detection window of the sensor unit has an upper end of H_sens_ 1 and a lower end of H_led_2.

  In addition, as described above, for example, as in Patent Document 2, the configuration of the sensor unit that virtually arranges the light paths of the light projecting unit or the light receiving unit using a half mirror and is disposed at the same position is as follows. 18 and FIG. 19 are included.

  As described above, considering all the positional relationship between the light projection window that is the light projection range of the light projecting unit and the light reception window that is the light reception range of the light receiving unit, "The upper end is equal to the higher of the upper end of the effective light projection window and the upper end of the effective light reception window", and "the lower end of the effective light shielding detection window of the sensor unit is equal to the lower end of the effective light emission window. It is equivalent to the higher of the lower ends of the target light receiving windows.

  This can be organized as follows:

H_opt_1 = Higher (H_led_1, H_sens_1) (1)
H_opt_2 = Higher (H_led_2, H_sens_2) (2)
here,
H_opt_1: Upper end of effective light shielding detection window of sensor unit H_opt_2: Lower end of effective light shielding detection window of sensor unit H_led_1: Upper end of effective light projection window of sensor unit H_led_2: Lower end of effective light projection window of sensor unit H_sens_1: Lower end of effective light receiving window of sensor unit H_sens_2: Lower end of effective light receiving window of sensor unit Higher (* 1, * 2): Calculation to select higher one from * 1, * 2

<Extended definition of common 3D shading detection area>
As described so far, for example, in the configuration of FIG. 2A, two planes S_top and S_bottom as shown in FIG. 2B are defined, and the upper ends of the effective light-shielding detection windows of the two sensor units 1L and 1R are the plane S_top. In addition, if the lower end substantially coincides with the plane S_bottom, the three-dimensional shading detection area related to the sensor units 1L and 1R can be made common, and the depth of shading shadow (light shielding) observed by each sensor unit can be made common. Rate) is observed as approximately the same value.

  This is not limited to the case of the two sensor units described above, and generally, in a coordinate input device composed of three or more sensor units, the upper ends of effective light shielding detection windows of all sensor units are flat. If the lower end of S_top substantially matches the plane S_bottom, all three-dimensional shading detection areas can be made common.

  In the case of the compound eye configuration of FIG. 1A, planes S_top and S_bottom as shown in FIG. 1B are defined. In this case, in the optical units L1, L2, R1, and R2 built in the sensor units 1L and 1R, the upper end of the effective light-shielding detection window of each optical unit substantially coincides with the plane S_top, and the lower end substantially coincides with the plane S_bottom. If so, all three-dimensional shading detection areas can be made common, and the depth (shading ratio) of the shading shadow observed by each optical unit is observed as substantially the same value.

  Hereinafter, some application examples in the configuration of FIG. 2B will be described.

  For example, FIG. 20 is configured so that two coordinates can be input by arranging a new sensor unit 1C on the same straight line of the sensor units 1L and 1R. Also in this case, if the upper end of the effective shading detection window of each sensor unit substantially coincides with the plane S_top and the lower end substantially coincides with the plane S_bottom, all three-dimensional shading detection areas can be made common, respectively. The depth of the light-shielding shadow (light-shielding rate) observed by the optical unit is observed as substantially the same value.

  Further, as shown in FIG. 21, even when the shape of the retroreflective portion 4c is trapezoidal and the planes S_top and S_bottom have a gradient in the X direction, the effective light shielding detection window of each sensor unit is If the upper end substantially coincides with the plane S_top and the lower end substantially coincides with the plane S_bottom, all three-dimensional shading detection areas can be made common, and the depth of shading shadow (light shielding ratio) observed by each optical unit can be made. ) Are observed as substantially the same value.

  Furthermore, as shown in FIG. 20 and FIG. 21, when the sensor units are not aligned on a straight line, for example, as shown in FIG. 22, the sensor unit 1C is located in the coordinate input effective area 3 more than the sensor units 1L and 1R. Even when the sensor units are arranged at positions separated from each other, if the upper end of the effective light shielding detection window of each sensor unit substantially coincides with the plane S_top and the lower end substantially coincides with the plane S_bottom, all the three-dimensional light shielding detection regions. The depth of the light shielding shadow (light shielding rate) observed by each optical unit is observed as substantially the same value.

  Further, as shown in FIG. 23, even if new sensor units 2C, 3C, etc. are added, the upper end of the effective light-shielding detection window of each sensor unit is substantially coincident with the plane S_top, and the lower end is substantially coincident with the plane S_bottom. For example, all three-dimensional shading detection areas can be made common, and the depth (shading rate) of the shading shadow observed by each optical unit is observed as substantially the same value.

  That is, the upper side and the lower side of the effective retroreflective portion have a relationship forming the first plane and the second plane, respectively, and each sensor unit has an effective light-shielding detection window at that position, It suffices to fill the gap between the first and second planes.

  Here, both the first and second planes need to be flat surfaces, not curved surfaces or creased surfaces. However, these first and second planes do not necessarily have to be parallel. Furthermore, the retroreflecting unit and the sensor unit do not necessarily have to be positioned along the periphery of the coordinate input effective area, and are arranged from a position slightly separated (down) as long as a predetermined condition is satisfied. Also good.

  As described above, the condition described so far is that the shadow depth (light-shielding rate) observed by the sensor unit when there is an input from the pointing tool can be observed at substantially the same value by all the sensor units. Yes, it is not a condition for calculating correct coordinates.

  That is, in order to calculate correct coordinates, each retroreflecting unit and each sensor unit are arranged in a plane in an appropriate relationship in the coordinate input plane direction substantially parallel to the first and second planes. Needless to say, you have to.

  Of course, Embodiments 1 and 2 of the present invention also satisfy the above conditions.

In other words, the characteristic condition that characterizes the configuration of the coordinate input device according to the present invention is most generalized as follows. The lower side of the retroreflective part constitutes a substantially common second plane,
Observation by each sensor unit when the upper end of the effective shading detection window of each sensor unit substantially coincides with the first plane and the lower end of the effective shading detection window substantially coincides with the second plane. The depth of the shaded shadow (shading rate) is observed as approximately the same value. "
It can be expressed as

<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. In the following description, when referring to FIG. 1A (or FIG. 2A) or 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 the light and provides an electrical shield, light receiving lenses (for example, fθ lenses) 106A and 106B as a condensing optical system, It comprises diaphragms 108A and 108B that roughly limit the incident direction of incident light, and infrared filters 107A and 107B that prevent the incidence of extraneous light (disturbance light) such as visible light.

  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 throttles 108A and 108B are formed integrally with the lower hood 109. However, it goes without saying that the diaphragms 108A and 108B may be separate parts, and further, the throttle 108A is disposed on the upper hood 103 side. And 108B and the light receiving lenses 106A and 106B are provided to facilitate positioning of the light receiving portion with respect to the light emission center of the light projecting portion (that is, all the main optical components are arranged only by the upper hood 103). Can also be realized.

  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 portions in the sensor unit 1L (1R) are arranged so that the principal ray directions thereof are substantially parallel with a predetermined distance d apart, and each light projecting lens. Each of 102A and 102B is configured to project light in a range of approximately 90 °.

  FIG. 26B is a cross-sectional view of the portion indicated by the thick arrow in FIG. 26A. The light from the infrared LED 101A (101B) is a light beam that is limited to be approximately parallel to the coordinate input surface by the projection lens 102A (102B). As described above, the light is projected mainly on the retroreflective portion 4.

  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 Embodiment 1, the light projecting unit and the light receiving unit have an arrangement configuration (see FIG. 26B) that is overlapped with the vertical direction of the coordinate input effective area 3 that is the coordinate input surface, and the front direction (coordinates). When viewed from the direction perpendicular to the input surface, it corresponds to the light emission center of the light projecting unit and the reference position of the light receiving unit (that is, the reference point position for measuring the angle. In the first embodiment, the diaphragm 108A (108B). ), Which is the point where the light rays intersect in the figure).

  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 configured to be 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. The light is reflected, 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. Although the light condensing region is used to share components, the present invention is not limited to this, and it goes without saying that 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, a digital signal obtained by demodulating the pen signal is output from the pen signal receiving unit 5 that receives the pen signal from the pen, and is input to the sub CPU 24 as a pen signal detection circuit. After the signal is analyzed, 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 (the light projecting unit and the 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 °, and of course the range is, for example, 100 °. Although it is possible to set and design the effective visual field range to be larger, for example, the optical distortion of optical components (for example, lenses) constituting the optical unit increases, and the optical system is configured at low cost. This is disadvantageous.

  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 of the first embodiment, in order to make the casing frame determined by the coordinate input effective area 3 and the casing 172 as small as possible, one light receiving unit in the sensor unit 1L (1R) All areas of the effective area 3 are stored in the effective field of view, but the other light receiving unit is set so that the area defined by the area 173 in the figure is outside the effective field of view.

  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.

  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 shadow position (angle) obtained by each optical unit are calculated from the light intensity distribution, and the optical unit L1 or L2 constituting the sensor unit 1L and the optical unit constituting the sensor unit 1R. Four types of combinations obtained from R1 or R2, 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, the detection state of the number of shadows in each optical unit is determined based on the “LR combination” and the number of shadows detected by each optical unit, and coordinate candidate points used for coordinate calculation are determined based on the determination result. A coordinate candidate point determination routine (steps S103 to S114) 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 (step S103 to step S105, step S108, and step S109), and a coordinate calculation method [1] to a predefined coordinate calculation method according to the determined detection state is performed. The coordinates are calculated in [4] (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 processing 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 disposed around the coordinate input effective area is configured so as to satisfy the above-described feature condition and the expressions (1) and (2). A shadow detected by each sensor unit with the same input is prevented from being detected with a difference in level (light shielding ratio) in each sensor unit, and is always 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. 10 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. However, the structure of the built-in optical unit (light receiving unit and light projecting unit) is different, and the visual field range of the sensor units 1L and 1R is different. Is approximately 90 degrees, whereas the field of view of the sensor unit 1C is approximately 180 degrees.

The most important thing is that the configuration of the sensor units 1L, 1R, and 1C and the retroreflective unit arranged around the coordinate input effective area 3 is the characteristic condition in the first embodiment and the expressions (1) and (2). Satisfied.

  That is, also in the second embodiment, the upper sides of all effective retroreflective portions located around the coordinate input effective area form one plane (first plane), and the effective retroreflective portions The lower side forms one plane (second plane), and the upper end of the effective light shielding detection window of each sensor unit substantially coincides with the first plane, and the lower end substantially coincides with the second plane. It is.

  With this configuration, when the input is performed by the pointing tool, the shaded shadow depth (shielded rate) observed in each of the sensor units 1L, 1R, and 1C is observed as substantially the same value. .

  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), and the coordinate calculation methods [5a] to [5c defined in advance according to the determined detection state. ] To calculate coordinates (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 embodiments have been described in detail above, the present invention can take an embodiment as, for example, a system, an apparatus, a method, a program, or a storage medium, and specifically includes a plurality of devices. The present invention may be applied to a system that is configured, or may be applied to an apparatus that includes 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 embodiment is directly or remotely supplied to the system or apparatus, and the computer of the system or 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.

  As a recording medium for supplying the program, for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card ROM, DVD (DVD-ROM, DVD-R) and the like.

  As another program supply method, a client computer browser is used to connect to an Internet homepage, and the computer program of the present invention itself or a compressed file including an automatic installation function is downloaded from the homepage to a recording medium such as a hard disk. Can also be supplied. 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. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS running on the computer based on an instruction of the program is a part of the actual processing. Alternatively, the functions of the above-described embodiment can be realized by performing all of them and performing the processing.

  Furthermore, after the program read from the recording medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion board or The CPU or the like provided in the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are also 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 characteristic of the retroreflection part 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 characteristic of the retroreflection part 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 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 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 the input operation of FIG. 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 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 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 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 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 (6)

A coordinate input device for detecting a designated position on a coordinate input area,
A plurality of sensor means provided around the coordinate input area, comprising: a light projecting unit that projects light to the coordinate input area; and a light receiving unit that receives incoming light;
A plurality of retroreflective means provided around the coordinate input region and 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;
A light shielding detection window in which the upper side of the member constituting the retroreflective means forms a common first plane, and the lower side of the member forms a common second plane, and is a light shielding detection range of the sensor means The sensor means and the retroreflective means are arranged such that the upper end portion of the light shielding detection window is located on the first plane and the lower end portion of the light shielding detection window is located on the second plane,
The three-dimensional shading detection area related to the plurality of sensor means is a space sandwiched between the first plane and the second plane, and has a common three-dimensional solid shape corresponding to the coordinate input area. A coordinate input device characterized by that. The three-dimensional shielding detection region, the shape of the retroreflector facing the sensor means, the coordinate input device according to claim 1, wherein a three-dimensional stereoscopic defined by the light shielding sensing window . The light-shielding detection window is a higher one of the lower end of the light projecting window that is the light projecting range of the light projecting unit provided in the sensor means and the lower end of the light receiving window that is the light receiving range of the light receiving unit provided in the sensor means. The coordinate input device according to claim 1, wherein the coordinate input device is defined as a lower end, and the upper end of the light projecting window and the upper end of the light receiving window is set as the upper end. The sensor means includes retroreflective means in which the field of view of the light projecting unit relates to the sensor means with respect to a direction perpendicular to the coordinate input area, and the field of view of the light receiving unit relates to retroreflection to the sensor means. The coordinate input device according to claim 1, further comprising: means. 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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