JP2005346231A - Optical digitizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve detection precision by detecting not only retroreflected light of a pen tip, but a shadow of the pen tip and retroreflected light of its center part. <P>SOLUTION: A pen structure of the present invention is such that coordinates are detected from both pieces of information of a light emission part and a light shield part by using a difference in wavelength range between retroreflected light of a frame and retroreflected light of the pen, but a similar detection waveform can be obtained by providing an ordinary resin material (including a transparent material) around a retroreflective material of the pen, so a (transparent) pen tip cap and a retroreflective material cover of a frame which are realized with higher possibility have wavelength characteristics, respectively. A light shield shadow of the periphery of the pen tip is also detected, so the light shield shadow is prevented from being buried in the retroreflected light of the frame and further the pen and a finger can be discriminated from each other through countermeasures against a hand touch and wavelength-switched light emission. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coordinate input device, and more specifically, coordinates used to control a connected computer or to write characters, figures, etc. by inputting coordinates by pointing to an input surface with an indicator or a finger. The present invention relates to a technology for improving the performance of an input device.

  In particular, the present invention provides a retroreflective light shielding method in which a retroreflective material is provided around the input surface, a retroreflective material is provided on the pointing tool, and the indicated position coordinates are input by detecting a light shielding state by the pointing tool or the like. The present invention relates to a coordinate input device.

  Conventionally, as this type of device, various types of touch panels have been proposed or commercialized, and it can be used widely because it can easily operate a PC on the screen without using special equipment. It has been.

  There are various methods such as a method using a resistance film and a method using ultrasonic waves. As shown in Patent Document 1 as a method using light, the method recurs outside the coordinate input surface. In the configuration in which a reflective sheet is provided, the light from the means for illuminating the light is reflected by the retroreflective sheet, and the light distribution is detected by the light receiving means, the angle of the area within the input area that is shielded by a finger or the like is detected However, it is known to determine the coordinates of the shielding position, that is, the input position.

  Further, as in Japanese Patents Nos. 2 and 3, the retroreflective member is configured around the input region, and a device for detecting the coordinates of the portion where the retroreflected light is shielded is disclosed. .

  In these apparatuses, for example, in Patent Document 2, the angle of the light-shielding part is detected by detecting the peak of the light-shielding part by waveform processing calculation such as differentiation, and in Patent Document 3, comparison with a specific level pattern is performed. Shows a configuration in which one end and the other end of the light shielding portion are detected and the center of the coordinates is detected.

  Further, in Patent Document 1, when each pixel of the RAM imager is read and compared by a comparator, a light-shielding portion is detected, and when there is a light-shielding portion having a certain width or more, the centers of the pixels at both ends thereof are detected. A detection method for detecting (1/2 position) is shown.

On the other hand, Patent Document 4 discloses an apparatus that detects an angle by detecting reflected light from a reflective cursor and detects the coordinates of the cursor.
U.S. Pat.No. 4,507,557 Japanese Unexamined Patent Publication No. 2000-105671 Japanese Patent Laid-Open No. 2001-1472642 Japanese Patent Laid-Open No. 3-5805

  In the conventional method of blocking retroreflected light from the retroreflective material provided around the input surface with an indicator or a finger, a change in the detected light amount due to a simple shading shadow is detected. However, although various ideas have been made, there are naturally limitations, and it has been difficult to further improve the coordinate detection accuracy. In addition, a part of the hand holding the pointing device may be shielded from light during input, resulting in erroneous detection due to a hand. Further, in terms of function, as a characteristic of the light-shielding method, it was originally possible to input coordinates by using a finger or the like in addition to a pen-like pointing tool without selecting a pointing tool. It is difficult to identify whether the input is input, and for example, it is impossible to switch between the pending timing and the application depending on the input method. In the same conventional optical coordinate input method that detects reflected light from an indicator, the amount of increase in the amount of light is simply detected, so the detection accuracy is limited. In this method, In addition, it was impossible to give instructions with fingers other than wearing a special sack.

In the present invention, in order to solve the above problems, a plurality of light receiving detection means are provided at the corners of the coordinate input area surface, and the peripheral frame recursively is provided at the peripheral part of the coordinate input area and recursively reflects incident light. Reflecting means, light projecting means for projecting light onto the peripheral frame retroreflecting means, a specific light wavelength transmitting member provided on the incident side of the peripheral frame retroreflecting means, and the light receiving detecting means It has angle detection means for detecting the direction indicated by the pointing tool or the like from the change in the amount of light from the light projecting means reflected by the peripheral frame retroreflecting means, and based on a plurality of derived angle information, the indication An optical coordinate input device that calculates position coordinates on a coordinate input area surface designated by a tool,
The indicator is reflected by the peripheral frame retroreflecting unit around the indicator retroreflecting unit, and an indicator retroreflecting unit that retroreflects the light from the light projecting unit at the axial center of the indicator. A peripheral member that generates a shading shadow for light in a wavelength band transmitted through a specific light wavelength transmission characteristic member provided on the incident side of the peripheral frame retroreflecting means with the received light, and detected by the light receiving detection means, The position coordinates on the coordinate input area surface designated by the pointing tool or the like are detected from the light quantity change information of the retroreflected light retroreflected by the pointing tool retroreflecting portion and the light shielding shadow by the surrounding members of the pointing tool. It was set as the structure which has a means to do. By detecting the indicated position based on the two light quantity change information of the retroreflected light and the light shielding shadow in the pointing tool of the present invention, it is possible to further improve the coordinate detection accuracy, By distinguishing, the influence of the touch can be eliminated.

  Further, the transmission wavelength band of the specific light wavelength transmitting member provided on the incident side of the peripheral frame retroreflecting means and the peripheral member provided around the indicator retroreflecting portion is differentiated, and the projection is performed. By having means for switching the wavelength band of the light means, it is possible to discriminate between an instruction by an indicator and an instruction by a finger.

As described above, in the present invention, a plurality of light receiving detection means are provided at the corners of the coordinate input area surface, and the peripheral frame retroreflecting means is provided at the periphery of the coordinate input area and recursively reflects incident light. A light projecting means for projecting light onto the peripheral frame retroreflecting means, a specific light wavelength transmitting member provided on the incident side of the peripheral frame retroreflecting means, and the peripheral frame detected by the light receiving detecting means It has an angle detection means for detecting the direction indicated by the pointing tool or the like from the change in the amount of light from the light projecting means reflected by the retroreflecting means, and the pointing tool or the like is based on a plurality of derived angle information. An optical coordinate input device for calculating a position coordinate on a designated coordinate input area surface,
The indicator is reflected by the peripheral frame retroreflecting unit around the indicator retroreflecting unit, and an indicator retroreflecting unit that retroreflects the light from the light projecting unit at the axial center of the indicator. A peripheral member that generates a shading shadow for light in a wavelength band transmitted through a specific light wavelength transmission characteristic member provided on the incident side of the peripheral frame retroreflecting means with the received light, and detected by the light receiving detection means, The position coordinates on the coordinate input area surface designated by the pointing tool or the like are detected from the light quantity change information of the retroreflected light retroreflected by the pointing tool retroreflecting portion and the light shielding shadow by the surrounding members of the pointing tool. It was set as the structure which has a means to do. The indication position is detected by detecting the indication position based on the two light quantity change information of the retroreflected light and the light shielding shadow in the indication tool of the present invention, as compared with the conventional case where the indication coordinates are calculated only from the light quantity distribution by the light shielding shadow. Coordinate detection accuracy can be improved due to the large amount of information regarding, and it is possible to identify whether the pointing state is due to a finger or according to the pointing tool of the present invention, so that it can be distinguished from a simple shading shadow due to a hand. Therefore, it is possible to eliminate the influence of handling. In particular, the tip portion of the characteristic indicator of the present invention has a simple configuration, high industrial feasibility, and at the same time high reliability.

  Furthermore, by giving a difference between the specific light wavelength transmission member provided on the incident side of the peripheral frame retroreflective means and the transmission wavelength band of the peripheral member provided around the indicator retroreflection part, The above characteristics can be utilized more clearly, and further, by having a means for switching the wavelength band of the light projecting means, it is possible to effectively discriminate between an instruction by an indicator and an instruction by a finger. The structure having a specific wavelength characteristic on the incident side of the retroreflective plate around the input region and the input region has a higher light transmission efficiency than the structure having other polarization characteristics and the like. / N can be improved, and a highly reliable coordinate input device can be realized.

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

(First embodiment)
A schematic configuration of a coordinate input device according to the present invention will be described with reference to FIG.

  In the figure, reference numerals 1L and 1R denote sensor units having a light projecting unit and a detecting unit, which are installed at a predetermined distance. The sensor unit is connected to a control / arithmetic unit 2 that performs control / calculation, receives a control signal from the control / arithmetic unit, and transmits a detected signal to the control / arithmetic unit. Reference numeral 3-1 denotes a peripheral frame retroreflective means having a retroreflective surface that reflects incident light in the direction of arrival as shown in FIG. 2, and is projected from the left and right sensor units in a range of approximately 90 °. Light is retroreflected toward the sensor unit. Further, as shown in FIG. 1-3, a specific light wavelength transmitting member 3-2 that transmits only light of a specific light wavelength on the incident side from the light projecting means of the peripheral frame retroreflecting means 3-1. It is arranged. Accordingly, the reflected light obtained by retroreflecting the light from the light projecting means by the peripheral frame retroreflecting means 3-1 has a light wavelength characteristic consisting of only a specific wavelength by the specific light wavelength transmitting member 3-2. It will be. The reflected light is detected one-dimensionally by the detection means of the sensor unit constituted by a condensing optical system and a line CCD, and the light quantity distribution is sent to the control / arithmetic unit. The wavelength region of the light wavelength transmitting member 3-2 is preferably substantially equal to or narrower than the bandwidth of the light wavelength characteristics of the light projecting means and the detecting means of the sensor units 1L and 1R. For example, since this is an infrared light region, the influence of disturbance light centered on visible light can be reduced.

  Reference numeral 5 denotes a coordinate input surface, which is composed of a display screen 4 of a display device such as a PDP, a rear projector, or an LCD panel, or a front plate 4 ′ that is a substantially transparent plate disposed on the front surface of the display screen 4. It can be used as an interactive input device.

  In such a configuration, when an input instruction is given to the input area with the pen-shaped pointing tool 6 shown in the figure, the light projected from the light projecting means is blocked, and the reflected light due to retroreflection cannot be obtained. For this reason, the amount of light cannot be obtained only at the input instruction position. Further, in the pointing tool 6 of the present invention, as shown in FIG. 1-2, the pointing tool retroreflecting portion 6-1 is arranged at the center of the axis of the pointing tool 6 at the tip portion of the pointing tool 6. And it has the structure which provided the surrounding member 6-2 around this indicator retroreflection part 6-1. The peripheral member 6-2 transmits the specific light wavelength transmission characteristic member 3-2 provided on the incident side of the peripheral frame retroreflective means 3-1, with the light reflected by the peripheral frame retroreflective means 3. A shading shadow is generated for light in the selected wavelength band. Details regarding the pointing tool 6 will be described later.

  The arithmetic control means of the main unit detects the light-shielding range of the input instructed part from the light quantity change of the left and right sensor units, specifies the detection point within the same range, and calculates the respective angles. The coordinate position on the input area is calculated from the calculated angle and the distance between the sensor units.

  In this way, PC operations such as drawing lines on the screen and operating switches and icons can be performed using pointing tools.

  Hereinafter, detailed description will be made for each part.

<Explanation on the distal end of the pointing tool as the main point of the present invention>
The general configuration of the pointing tool 6 in the present invention is as described above, but the detailed structure will be described with reference to FIGS. 1-2 is a side view of the distal end portion of the pointing tool 6, and the lower view is a cross-sectional view of the distal end portion of the pointing tool 6. FIG. At the tip portion of the pointing tool 6, the pointing tool retroreflecting portion 6-1 is disposed at the axial center portion of the pointing tool 6 as described above. The pointing tool retroreflective portion 6-1 has, for example, a cylindrical shape in which the axis of the pointing tool 6 is substantially the same, and a retroreflective layer having, for example, a bead structure is formed on the side surface of the cylinder. This retroreflective layer with a bead structure is a bead layer made of glass beads, an aluminum deposited film at an approximate focal point of the lens effect of the bead, or an electrode coating such as silver, or other optical reflective properties. The reflective layer to be formed and a binder resin layer or the like for fixing them are formed so that light incident on the bead surface is reflected in substantially the same direction as the incident direction. These are generally commercially available as retroreflective tape, and may be formed into a cylindrical shape. The indicator retroreflecting portion 6-1 may be formed not only by a bead type but also by a prism or corner cube type.

  Further, a peripheral member 6-2 is provided around the indicator retroreflecting portion 6-1 as shown in the figure. The peripheral member 6-2 is a member made of translucent resin or the like, and the light projected from the light projecting unit and the light reflected by the peripheral frame retroreflecting unit 3-1 are instructed above. It is arranged so as to pass through the peripheral member 6-2 when it enters the retroreflective portion 6-1. In the figure, the shape is shown as a side surface of a truncated cone, but a simple conical shape or other shapes may be used as long as the light-shielding portion has a sufficient thickness and shape to be detected as a light amount change.

  With the configuration of the indicator 6 in the present invention, the light projected from the light projecting means is directly incident on the axial center of the tip of the indicator 6 and, as shown in the figure, the surrounding member 6-2. Is transmitted to the pointing device retroreflecting section 6-1 and retroreflected there, and the reflected wave passes through the surrounding member 6-2 and reaches the sensor unit having the 1L and 1R detecting means. To do. On the other hand, the light reflected by the peripheral frame retroreflecting means 3-1 is transmitted through the specific light wavelength transmission characteristic member 3-2, and is reflected light in a specific wavelength band as a peripheral member 6-2 of the indicator 6. To reach. Here, the light incident on the axial center portion of the peripheral member 6-2 has a high transmittance and a low reflectivity because the incident angle to the peripheral member 6-2 is small as shown in the figure, and the light is transmitted and recurs. The light enters the reflecting portion 6-1, is retroreflected, passes through the surrounding member 6-2 again, and is emitted to the peripheral portion of the coordinate input area. On the other hand, the light incident on the outer side shifted from the axial center of the peripheral member 6-2 has a large incident angle, a high reflectance, and a low transmittance, in relation to the angle of the surface of the peripheral member 6-2. Therefore, the amount of transmitted light decreases as indicated by the dotted arrow, and even a small amount of incident light is refracted and attenuated inside the indicating member, and as a result, reaches the sensor unit having the 1L and 1R detection means. The amount of light to be reduced is detected as a shading shadow. Further, although not shown, the light projected from the light projecting means and directly incident on the outer side shifted from the axial center of the tip of the pointing tool 6 is not transmitted and attenuated as in the case of the reflected light. However, this results in attenuation of the amount of light to the peripheral frame retroreflecting means 3-1, which is eventually detected as a light shielding shadow similar to the above by the attenuation of the retroreflected light in the reverse path.

  As described above, due to the structure of the tip portion of the pointing tool 6 of the present invention, when the coordinate input area is pointed by the pointing tool 6, it is detected by the sensor unit having the 1L and 1R detecting means. The light quantity distribution is a light quantity distribution in which a light quantity increase peak due to retroreflected light exists in the light-shielding shadow. Detailed detection of the light amount distribution will be described later.

  The shape of the surrounding member 6-2 is shown as a cylindrical shape in the figure. However, if the peripheral member 6-2 is made of a constant thickness member, the same incident angle and reflectivity can be obtained even in a polygonal prism structure of about octagon or more. Show the effect.

  As described above, it is desirable that the transmission wavelength region of the light wavelength transmission member 3-2 is substantially equal to or narrower than the bandwidth of the light wavelength characteristics of the light projecting means and the detection means of the sensor units 1L and 1R. However, it is not limited to this. For example, since this is an infrared light region, the influence of disturbance light centered on visible light can be reduced. Furthermore, in order to reduce the influence of disturbance light, a light wavelength transmitting member having a specific wavelength may be provided in the light projecting means and the detecting means of the sensor units 1L and 1R.

  The surrounding member 6-2 provided at the tip of the indicator 6 is formed of acrylic, polycarbonate, other transparent resin, or colored resin. Furthermore, not only a single material but the structure which bonded the film etc. on the said resin may be sufficient.

<Detailed explanation of sensor unit>
FIG. 3 is a configuration example of the light projecting means in the sensor unit.

3-1 is a view of the light projecting unit as viewed from above (perpendicular to the input surface). In the figure, reference numeral 31 denotes an infrared LED that emits infrared light, and the emitted light is projected by a light projection lens 32 in a range of approximately 90 °. On the other hand, 3-2 is a view of the same configuration seen from the side. In this direction (horizontal with respect to the input surface), in this direction, light from the infrared LED 31 is projected as a light beam restricted in the vertical direction,
Mainly, light is projected to the retroreflective means 3.

  FIG. 4 is a view of the detection means in the sensor unit as viewed from the direction perpendicular to the input surface.

  The detection means includes a one-dimensional line CCD 41, lenses 42 and 43 as a condensing optical system, and a diaphragm 44 that limits the incident direction of incident light. As described above, an infrared filter 45 that prevents the incidence of extraneous light such as visible light may be added.

  The light from the light projecting means is reflected by the retroreflective member, passes through the infrared filter 45 and the stop 44, and the light in the approximately 90 ° range of the input surface is incident on the CCD detection surface by the condensing lenses 42 and 43. An image is formed on the pixel depending on the angle, and the light amount distribution for each angle is shown. That is, the pixel number represents angle information.

  FIG. 5 shows a configuration in which the light projecting unit and the detection unit are overlapped to form the sensor unit 1 when viewed from the horizontal direction with the input surface.

  The distance between the optical axes of the light projecting means and the detecting means may be set in a range that can be sufficiently detected from the angular characteristics of the retroreflective member.

<About reflective members>
The retroreflective member 3 of FIG. 1 has a reflection characteristic with respect to an incident angle.

  When the retroreflective tape is configured flat as shown in FIG. 6, the amount of reflected light obtained when the angle from the reflective member exceeds 45 degrees is reduced, and the change occurs when there is a shield. Will not be enough.

  The amount of reflected light is determined by the light amount distribution (illumination intensity and distance), the reflectance of the reflecting member (incident angle, the width of the reflecting member), and the imaging system illuminance (cosine fourth law).

  If the amount of light is insufficient, it is conceivable to increase the illumination intensity. However, if the reflection distribution is not uniform, when a strong portion of light is received, that portion is saturated by the CCD, which is the light receiving means. There is a limit to increasing the illumination intensity.

  In other words, it is possible to increase the amount of light incident on the low light amount portion by making the reflection distribution of the reflecting member as uniform as possible.

  In order to make the angle direction uniform, the member to which the retroreflective member 3 is attached has a shape in which triangular prisms are arranged as shown in FIG. 7, and the retroreflective member 3 is installed thereon. By doing so, the angle characteristics can be improved. The angle of the triangular prism may be determined from the reflection characteristics of the retroreflective member, and the pitch is preferably set to be equal to or less than the detection resolution of the CCD. Note that the structure of the retroreflective member 3 itself is configured by a bead type, a prism, a corner cube type, or the like, similar to the indicator retroreflective portion 6-1 of the indicator 6.

<Description of control / arithmetic unit>
Between the control / arithmetic unit of FIG. 1 and the sensor units 1L and 1R, a CCD control signal, a CCD clock signal and a CCD output signal, and an LED drive signal are exchanged.

  FIG. 8 is a block diagram of the control / arithmetic unit. The CCD control signal is output from an arithmetic control circuit 83 constituted by a one-chip microcomputer or the like, and performs CCD shutter timing, data output control, and the like. The clock for the CCD is sent from the clock generation circuit 87 to the sensor unit, and is also input to the arithmetic control circuit 83 in order to perform various controls in synchronization with the CCD.

  The LED driving signal is supplied from the arithmetic control circuit 83 to the infrared LEDs of the sensor unit through the LED driving circuits 84L and 84R.

  Detection signals from the CCD, which is the detection means of the sensor unit, are input to the AD converters 81L and 81R of the control / arithmetic unit, and are converted into digital values under the control of the arithmetic control circuit.

  The converted digital value is stored in 82 memory and used for angle calculation.

  A coordinate value is obtained from the calculated angle and is output to an external PC or the like via the serial interface 88 or the like.

<Explanation of light intensity distribution detection>
FIG. 9 is a timing chart of control signals.

  Reference numerals 91, 92 and 93 are control signals for CCD control, and the shutter release time of the CCD is determined by the interval of the 91SH signal. Reference numerals 92 and 93 denote gate signals to the left and right sensors, respectively, for transferring the charges of the photoelectric conversion unit in the CCD to the reading unit.

  Reference numerals 94 and 95 denote left and right LED drive signals, and 94 drive signals are supplied to the LEDs via the LED drive circuit in order to light one LED in the first cycle of SH. The other LED is driven in the next cycle. After the driving of both LEDs is completed, the CCD signal is read from the left and right sensors.

  When the signal to be read is not input, a light amount distribution as shown in FIG. 10 is obtained as an output from each sensor. Of course, such a distribution is not necessarily obtained in any system, and the distribution changes depending on the characteristics of the peripheral frame retroreflecting means 3-1, the characteristics of the LED, and changes in time (such as dirt on the reflecting surface). .

  In the figure, the A level is the maximum light amount, and the B level is the lowest level.

  That is, in a state where there is no reflected light, the level obtained is near B, and the direction of the A level is increased as the amount of reflected light increases. Thus, the data output from the CCD is sequentially AD converted and taken into the CPU as digital data.

  FIG. 11A is an example of output when input is performed with a conventional pointing tool or finger, that is, when reflected light is blocked.

  Since the reflected light is blocked by the conventional indicator or finger at the portion C, the amount of light is reduced only at that portion.

  Further, in the present invention, as described above, the indicator retroreflecting portion 6-1 is arranged at the axial center portion of the indicator 6 at the tip portion of the indicator 6, so that retroreflected light is emitted therefrom. As shown in the figure, the surrounding member 6-2 is provided in the periphery, in which the light transmission amount is reduced to become a light-shielding shadow. Therefore, as shown in FIG. In the portion C, the light amount distribution has a light amount increase portion D having a light amount increase peak due to retroreflected light. That is, in the structure of the tip portion of the pointing tool 6 of the present invention, the diameter of the pointing tool retroreflecting portion 6-1 at the axial center portion is smaller than the diameter of the surrounding member 6-2. The pixel width of the shadow light amount decrease portion C is larger than the pixel width of the light amount increase portion D, and a characteristic light amount distribution can be obtained instead of a simple light amount decrease distribution due to the conventional shading shadow. By distinguishing it from a simple light intensity distribution in the case of input, it is possible to distinguish the input between the finger and the pointing tool, or to distinguish the shading shadow caused by a part of the hand holding the pointing tool, thereby removing the influence of the hand. it can. Alternatively, by using this characteristic light intensity decrease portion and increase portion, disturbance light can be detected by detecting retroreflected light in combination with a conventional light intensity decrease portion that is easily affected by disturbance light. Therefore, the coordinate detection can be performed with higher accuracy.

  The following describes an embodiment in which coordinate detection is performed based on the distribution of the light intensity decreasing portion, and when the characteristic light intensity decreasing portion and increasing portion distribution due to the pointing tool appears, it is determined that the input is performed by the pointing tool. .

  Specifically, an initial state with no input as shown in FIG. 10 is stored in advance, and whether there is a change as shown in FIG. 11-1 (or FIG. 11-2) in each sample period. If there is a change, an operation is performed to determine an input angle using that portion as an input point.

<Explanation of angle calculation>
In calculating the angle, it is first necessary to detect the light shielding range. For simplicity of explanation, the light amount distribution related to retroreflected light from the pointing tool retroreflecting unit 6-1 is not considered.

As described above, since the light quantity distribution is not constant due to changes in timekeeping, it is desirable to store it when the system is started. By doing so, for example, even if the retroreflective surface is dirty with dust or the like, it can be used unless it is not completely reflected.
Hereinafter, data of one sensor will be described, but the same processing is performed on the other.

  When the power is turned on, the CCD output is first AD-converted without illumination from the light projecting means without any input, and this is stored in the memory as Bas_data [N]. This is data including variations in CCD bias and the like, and is data near the level B in FIG. Here, N is a pixel number, and a pixel number corresponding to an effective input range is used.

  Next, the light quantity distribution in the state illuminated from the light projecting means is stored. This data is represented by the solid line in FIG. 10 and is Ref_data [N].

  Using these data, it is first determined whether an input has been made or whether there is a light shielding range.

  Data of a certain sample period is assumed to be Norm_data [N].

  First, in order to specify the light shielding range, presence / absence is determined based on the absolute amount of change in data. This is to prevent erroneous determination due to noise or the like and to detect a certain amount of reliable change.

  The absolute amount of change is calculated for each pixel as follows and compared to a predetermined threshold value Vtha.

Norm_data_a [N] = Norm_data [N] − Ref_data [N] (1)
Here, Norm_data_a [N] is an absolute change amount in each pixel.

  Since this process only takes a difference and compares it, it does not use much processing time, and therefore it is possible to determine whether or not there is an input at high speed.

  When the number of pixels exceeding the threshold value Vtha for the first time is detected exceeding a predetermined number, it is determined that there is an input.

Next, in order to detect with higher accuracy, a change ratio is calculated to determine an input point.
Here, assuming that the reflectance of the A region has decreased due to dirt or the like, the distribution of Ref_data [N] at this time has a smaller amount of reflected light in the A region as indicated by 13-1 in FIG. In this state, if an indicator or the like is inserted as shown in FIG. 12 and almost half of the retroreflective member is covered, the amount of reflected light is substantially halved, so the distribution Norm_data [ N] is observed.

  When (1) is applied to this state, the result becomes 14-1 in FIG. Here, the vertical axis represents the differential voltage from the initial state.

  If a threshold is applied to this data, the original input range may be lost. Of course, it can be detected to some extent if the threshold value is lowered, but it may be affected by noise or the like.

  Therefore, if the ratio of change is calculated, the amount of reflected light is the first half in both the A area and the B area, so the ratio is calculated by the following equation.

Norm_data_r [N] = Norm_data_a [N] / (Bas_data [N]-Ref_data [N]) (2)
This calculation result is as shown in FIGS. 14 and 14-2, and is represented by a fluctuation ratio. Therefore, even when the reflectance is different, it can be handled equally and detection can be performed with high accuracy.

  The threshold value Vthr is applied to this data, and the angle is determined from the pixel numbers of the rising and falling portions with the center of both as the input pixel.

  FIG. 14-2 is drawn schematically for the sake of explanation, and does not actually rise like this, but shows a different level for each pixel.

  FIG. 15 shows an example of detection after the ratio calculation is completed. Assume that when the detection is made with the threshold value Vthr, the rising portion of the light shielding area exceeds the threshold value at the Nrth pixel. Furthermore, it is assumed that the voltage falls below Vthr at the Nf-th pixel.

Keep the center pixel Np
Np = Nr + (Nf-Nr) / 2 (3)
However, in this case, the pixel interval becomes the minimum resolution.

  In order to detect more finely, a virtual pixel number across the threshold is calculated using the level of each pixel and the level of the previous pixel.

The level of Nr is now Lr. The level of Nr-1 pixel is Lr-1. Further, if the level of Nf is Lf and the number Nf-1 is Lf-1, the virtual pixel numbers Nrv and Nfv are
Nrv = Nr-1 + (Vthr-Lr-1) / (Lr-Lr-1) (4)
Nfv = Nf-1 + (Vthr-Lf-1) / (Lf-Lf-1) (5)
Virtual center pixel Npv
Npv = Nrv + (Nfv-Nrv) / 2 (6)
Determined by

  Thus, by calculating a virtual pixel number from the pixel number and its level, detection with higher resolution can be performed.

  The method for obtaining the central pixel of the light shielding range from the rise and fall of the light shielding range has been described above for the angle calculation of the present embodiment. However, the object for obtaining the indicated position of the pointing tool 6 is not limited to the light shielding range in the present invention. The light amount distribution detected by the light receiving detection means (sensor) of the present invention is a combination of the light amount distributions of the light shielding portion and the retroreflected light portion shown in FIG. 11-2 as described above. This is a feature of the present invention. However, this light quantity distribution is representative of a specified position on the coordinate input surface of the pointing tool. Actually, the light quantity distribution levels of the light shielding part and the retroreflected light part vary depending on the designated area. The pixel width indicated by C and D in FIG. 11-2 also varies. This is also affected by the positional relationship between the sensor units 1L and 1R and the coordinate input surface 5. As a tendency, the pixel width of the light-shielding range tends to increase when it is close to the sensor units 1L and 1R, and conversely, it becomes narrow when it is far away. At the same time, with respect to the retroreflected light from the pointing tool retroreflecting unit 6-1, the pixel width increases and the light quantity increases when close to the sensor units 1L and 1R. In some cases, saturation occurs when the light is not adjusted. On the other hand, as the distance increases, the pixel width becomes narrower and the peak of the amount of light tends to decrease. Therefore, for example, if the sensor units 1L and 1R are arranged with a sufficient distance from the coordinate input surface 5, the light quantity by the shortest position and the farthest position from the sensor unit 1L or 1R is indicated. The degree of change in the distribution is relatively small. Therefore, it is possible to obtain the central pixel of the light shielding range from the light shielding range in the above embodiment. However, when the sensor units 1L and 1R are arranged at a short distance with respect to the coordinate input surface 5, the shortest position from the sensor unit particularly with respect to the retroreflected light from the pointing tool retroreflecting unit 6-1. In the case of the instruction, the pixel width in the light quantity distribution of the retroreflected light is widened, and as a result, there is a case where the light shielding shadow portion cannot obtain a sufficient range for detecting it. Therefore, in order to prevent this state, depending on the arrangement of the sensor units 1L and 1R, the central pixel of the light shielding range is not obtained from the light shielding range of the above embodiment, but the retroreflection from the pointing tool retroreflecting unit 6-1. A method of obtaining the central pixel of the light quantity peak from the light quantity distribution of light may be used. A specific method for obtaining a pixel is the same as that for obtaining the central pixel from the light shielding range, and only the sign of the light amount distribution is reversed. That is, it is determined whether there is retroreflected light by comparing it with the threshold value. In this case, although detected simultaneously with the light shielding range, the rising and falling states in FIG. 11-2 rise at a, b, c, and d when the retroreflected light is small with respect to a certain threshold. Although two or more downhills can be obtained, when the indicated position is close to the sensor and the retroreflected light is large, only the retroreflected light portions b and c are obtained. In each case, the ratio of the change was calculated from the rise and fall of the light amount distribution of the retroreflected light, and calculated in the above-mentioned light shielding range. Similarly to the above, the virtual pixel number is obtained to obtain the center pixel.

  In order to calculate an actual coordinate value from the obtained center pixel number, it is necessary to convert it into angle information.

  In actual coordinate calculation described later, it is more convenient to obtain the value of the tangent at the angle rather than the angle itself.

  A table reference or a conversion formula is used for conversion from the pixel number to tan θ.

FIG. 16 is a plot of tan θ values against pixel numbers. An approximate expression is obtained for this data, and pixel number and tan θ conversion is performed using the approximate expression.
For example, when a high-order polynomial is used as the conversion formula, the accuracy can be ensured, but the order and the like may be determined in consideration of the calculation capability and accuracy specifications.

  When a fifth order polynomial is used, six coefficients are required, so this data may be stored in a nonvolatile memory or the like at the time of shipment.

If the coefficients of the fifth-order polynomial are now L5, L4, L3, L2, L1, L0,
tanθ is
tanθ = (L5 * Npr + L4) * Npr + L3) * Npr + L2) * Npr + L1) * Npr + L0 (7)
Can be represented.

  If the same thing is done for each sensor, the respective angle data can be determined.

  Of course, in the above example, tan θ is obtained, but the angle itself may be obtained, and then tan θ may be obtained.

<Description of coordinate calculation method>
Coordinates are calculated from the obtained angle data.

  FIG. 17 is a diagram showing a positional relationship with the screen coordinates.

  Each sensor unit is mounted on the left and right sides of the input range, and the distance between them is expressed as Ds.

  The center of the screen is the origin position of the screen, and P0 is the intersection of the angle 0 of each sensor unit.

  The respective angles are θL and θR, and tanθL and tanθR are calculated using the above polynomials.

At this time, the x and y coordinates of point P are
x = Ds * (tanθL + tanθR) / (1+ (tanθL * tanθR)) (8)
y =-Ds * (tanθR-tanθL-(2 * tanθL * tanθR)) / (1+ (tanθL * tanθR)) + P0Y (9)
Calculated by

<Identification of pointing tool and finger input>
The pixel number corresponding to the input point, the angle calculation corresponding to the pixel number, and the coordinate calculation have been described above. Next, the identification of the pointing tool and finger input according to the present invention will be described. In the state of pointing with a finger, the light quantity distribution is as shown in FIG. 11A. However, when the tip of the pointing tool 6 of the present invention has a structure having both retroreflective characteristics and light shielding characteristics as described above, FIG. As shown in -2, a light quantity distribution of the retroreflected light D is generated in the light-shielding portion C of the pointing tool 6. Here, the constant threshold value Vthr is first exceeded at the rising portion a with respect to the light-shielding portion C of the pointing device 6, then below the falling b with respect to the retroreflected light D, exceeded at the rising edge of c, and finally shielded. It falls below the falling part d with respect to the part C. The number of rising and falling edges and the pixel number are stored in a memory. In comparison with a certain threshold value, if it is determined that there is one rise and fall, it can be determined that there is no light quantity distribution of the retroreflected light D, so it is determined that there is an indication state with a finger, and rise and fall. Are determined to be in the instruction state by the pointing tool since it can be determined that the light quantity distribution of the retroreflected light D has occurred. More preferably, as described above, in order to avoid the influence of noise, the above rise and fall are obtained with respect to the change ratio, and the threshold value Vthr is obtained with respect to this ratio.

  In the coordinate calculation, the virtual pixel is calculated by the ratio calculation for the first rising a and the last falling d, the virtual central pixel is calculated, and the coordinate calculation is performed. That is, the rise and fall are stored in advance and distinguished from each other so that the change in the amount of light due to the light shielding of the pointing tool and the change in the amount of light due to the change in the retroreflection characteristics of the pointing tool are determined. Further, although not shown, in the case of an instruction by the pointing tool, in addition to the first rising a and the last falling d, pixel detection is performed for the falling b and the rising c related to the retroreflected light D, and this The value may be used as a correction value for the coordinate calculation value of the light shielding portion. Thereby, the coordinate detection precision by an indicator can be raised.

  In the above embodiment, when a light quantity increase distribution due to the retroreflection characteristic at the tip of the pointing tool 6 as shown in FIG. 11-2 is detected, rising and falling are detected with respect to one threshold value. The coordinate calculation and the pen-up / down detection are performed, but the light quantity increase distribution region by the pointing tool retroreflecting unit 6-1 is different from the surrounding member 6-2 in consideration of the fact that the fluctuation behavior is different. It is good also as judging by.

  Furthermore, the detected light amount distribution regarding the light shielding and retroreflected light may be changed according to the distance from the sensor unit in consideration of the large influence of the distance between the pointing tool and the sensor unit. This distance is obtained from coordinate values. That is, when the distance is closer to the sensor unit, the threshold value is increased because the retroreflected light of the pointing tool increases, and the threshold value is decreased because the retroreflected light of the pointing tool decreases as this distance increases. In this way, by changing the threshold for retroreflected light according to the distance from the sensor unit, it is possible to detect the coordinates and identify the indication state more accurately in the present invention.

<Flow chart showing the process from data acquisition to coordinate calculation>
FIG. 18A is a flowchart showing steps from data acquisition to coordinate calculation, in which coordinates are obtained from the light shielding range.

  When the power is turned on in S101, various initializations such as port setting of the arithmetic control circuit and timer setting are performed. S103 is a preparation for removing unnecessary charges that is performed only at startup. In a photoelectric conversion element such as a CCD, unnecessary charge may be accumulated when it is not operated. If the data is used as it is as reference data, it becomes impossible to detect or causes false detection. In order to avoid this, data is first read multiple times without illumination. In S103, the number of times of reading is set. In S104, unnecessary data is removed by reading data a predetermined number of times without illumination.

  S105 is a determination sentence for repeating a predetermined number of times.

  S106 is fetching of data without illumination as reference data, and corresponds to the above Bas_data.

The data fetched here is stored in the memory and used for calculation thereafter.
Data Ref_data corresponding to the initial light amount distribution when illuminated, which is another reference data, is taken in S108, and this is also stored in the memory.

  Up to this step is the initial setting operation when the power is turned on, and then the normal capturing operation is performed. In S110, the light amount distribution is captured as described above, and in S111, the presence / absence of a light-shielding portion is determined based on the difference value from Ref_data. If it is determined that there is no data, the process returns to S110 and capture is performed.

  At this time, if the repetition period is set to about 10 [msec], the sampling rate is 100 times / second.

  If it is determined in S112 that there is a light shielding area, the ratio is calculated in S113 by the processing of Expression (2). If it is determined in S112 that there is a light shielding area, coordinate calculation is started after this stage. A rising portion and a falling portion are determined by a threshold with respect to the obtained ratio, and the numbers are stored in a memory S114. Next, the center is calculated by the equations (4), (5) and (6). At this time, as described above, the first rising portion and the last falling portion are used in the calculation in S115. Tan θ is calculated from the obtained center value by an approximate polynomial, and x and y coordinates are calculated from the Tan θ values of the left and right sensor units using equations (8) and (9) S116. Next, it is determined whether the instruction is made by the pointing tool or the finger in S117. In the comparison with the above threshold value, when the number of falling parts or the number of falling parts is 1, it is determined as an instruction by a finger, and when this number is larger than 1, that is, when it is 2, it is determined as an input by an indicator. To do. According to this result, the instruction state identification flag is set S118 or reset S119.

  The above is a case where the coordinates are obtained from the light shielding range, but as described above, the coordinates may be provided from the light quantity distribution of the retroreflected light. A flowchart in this case is shown in FIG. After calculating the ratio with the memory data in s113, the number of rising edges and the number of falling edges are detected by a fixed threshold value in step s114-1, and stored in the memory. In step s114-2, it is determined whether the number of rising edges and the number of falling edges are each greater than 1. If it is determined that the number of rising edges is larger, it is determined that a light-shielding range that is sufficient for detection is detected. Except for the last rise and fall, that is, pixel detection is performed based on the light quantity distribution of retroreflected light, and it is determined in step s114-2 that the number of rises and the number of fall are less than 1, respectively, only the retroreflected light is present. It is determined that a range sufficient for detection is detected, and pixel detection is performed using the first and last rising and falling edges, that is, the light quantity distribution of retroreflected light. The following is the same as the case of obtaining coordinates from the light shielding range.

  Since the coordinate value and the instruction state are determined, the data is transmitted to the host PC S120. This may be sent by serial communication such as USB, RS232, etc., or by any interface. On the PC side, the driver interprets the data and moves the cursor, changes the mouse button state, etc. by referring to the coordinate values, flags, etc., so that the PC screen can be operated.

  When the process of S120 is completed, the process returns to the operation of S110, and thereafter this process is repeated until the power is turned off. The host PC can change the cursor type and line type, change the application according to the state, and the like by using the instruction state identification flag indicating whether the instruction tool is an instruction or a finger instruction.

  In the above flowchart, only the determination of the pointing state is performed. However, in the case of the pointing tool pointing state, as described above, a coordinate calculation algorithm to which information on the retroreflected light portion is further added is added to improve the coordinate detection accuracy. May be raised. In addition to the above flow chart, if only the light-shielded shadow part and the light-shielded shadow + the light quantity peak distribution due to retroreflected light are detected at the same time, it is determined that only the light-shielded shadow part is caused by hand. The coordinates may be calculated excluding that part.

(Second embodiment)
In the said Example, the wavelength of the specific light wavelength transmission member 3-2 provided in the incident side from the light projection means of the periphery frame retroreflection means 3-1, and the surrounding member 6-2 of the indicator 6 Although there is no particular limitation on the characteristic relationship, the wavelength transmission light characteristic having a certain relationship may be used. As a second embodiment of the present invention, the specific light wavelength transmission member provided on the incident side of the peripheral frame retroreflecting means has a first transmission wavelength band, and the periphery of the indicator retroreflective portion. If the surrounding member 6-2 provided in the second transmission wavelength band has a second transmission wavelength band, the second transmission wavelength band is narrower than the first transmission wavelength band, and the wavelength of the light receiving means and the light projecting means The band includes a part of the second wavelength transmission region and a portion that is not the second wavelength transmission region but the first wavelength transmission region. For example, as shown in the wavelength spectral characteristic of FIG. 19, the specific light wavelength transmission member provided on the incident side of the peripheral frame retroreflecting means has a transmission limit wavelength of 700 nm in the first transmission wavelength band, The surrounding member provided around the indicator retroreflective portion is configured by an infrared filter of, for example, methacrylic resin (acrylic resin) having a second transmission wavelength band of 950 nm. The sensor units 1L and 1R each having a light projecting unit and a detecting unit are configured to have a transmission band equal to or wider than the first transmission wavelength band. Naturally, in this case, the transmission band is wider than the second transmission wavelength band. Specifically, the device itself of the light projecting means and the detecting means may have this wavelength characteristic, or an optical filter having this characteristic may be arranged.

  According to the second embodiment described above, the wavelength characteristic of the frame retroreflected wave transmitted through the specific light wavelength transmitting member provided on the incident side of the peripheral frame retroreflecting means shown in FIG. When the frame retroreflected wave reaches the peripheral member 6-2 at the tip of the indicator 6, the wavelength band of 700 to 950 nm is obtained by the spectral characteristics of FIG. 19 of the peripheral member 6-2. The amount of light corresponding to this band is not transmitted, but only the amount of light corresponding to the band of 950 nm or more, so that the detected light amount is reduced correspondingly and becomes a shading shadow. As a result, the light quantity increase due to the retroreflected light in the light quantity reduction part of the shading shadow due to the difference in transmittance due to reflection or the like between the axial center part and the outer part shifted from the axial center described in the first embodiment. Since the effect of the characteristic light quantity distribution in which the peak light quantity increasing portion exists is further promoted and appears clearly, the finger and the pointing tool in the first embodiment are identified, the hand is corrected, and the coordinate detection is further performed. The effect on higher accuracy is further promoted. The numerical values of the wavelengths shown above are examples, and it goes without saying that other wavelength bands may be used as long as the relationship between the first wavelength band and the second wavelength band is maintained.

  Furthermore, as shown in FIG. 20, it is provided around the first transmission wavelength band of the specific light wavelength transmission member provided on the incident side of the peripheral frame retroreflective means and the indicator retroreflective portion. Further, the second transmission wavelength band of the peripheral member 6-2 may have a band pass band characteristic having different center wavelength values and having a lower limit and an upper limit of the transmission band. In this case, the bandwidths of the light projecting unit and the light receiving detection unit include at least the center wavelength regions of the first and second transmission wavelength bands. In this configuration, first, the light projected on the distal end portion of the pointing tool 6 passes through the peripheral member 6-2 and is retroreflected from the pointing tool retroreflecting portion 6-1 with respect to the axial center portion. The light again passes through the surrounding member 6-2 and enters the light receiving detection means. In addition to the influence of the reflection angle, the second transmission of retroreflected light in the first transmission wavelength band of the light wavelength transmission member 3-2 is applied to the portion outside the axis of the tip portion of the pointing tool 6. Since the peripheral member 6-2 having the wavelength band hardly transmits light, a clear shading shadow is formed. Therefore, the characteristic light amount distribution effect in which the light amount increase portion of the light amount increase peak due to the retroreflected light exists in the light amount decrease portion of the light-shielding shadow is further promoted and clearly appears. The effect of identifying the pointing tool and correcting the hand movement and further improving the accuracy of coordinate detection are further promoted.

(Third embodiment)
In the above embodiment, it is configured by a single light projecting means having a constant wavelength band, but the first transmission wavelength band of the light wavelength transmission member shown in FIG. 20 in the second embodiment, Projecting means having two transmission wavelength bands corresponding to the bandpass band characteristics of the second transmission wavelength band of the surrounding member 6-2, and projecting by switching between the two light projecting means, in each case A configuration may be adopted in which it is determined whether an instruction is made by a finger or an instruction tool by the detected light amount distribution. In this case, the received light detection means has a detection sensitivity characteristic that combines the first and second transmission wavelength bands.

  A flowchart in this case is shown in FIG. A description of portions common to the previous embodiment is omitted. First, light is projected in the second transmission wavelength band as the light projection wavelength band in the basic state. In this case, since it is not the transmission band of the light wavelength transmitting member 3-2, retroreflected light from the peripheral frame retroreflecting means 3-1 is not generated. If instructed by the pointing tool 6, the light projected on the tip of the pointing tool 6 passes through the peripheral member 6-2 having the second transmission wavelength band with respect to the axial center. Then, the light is retroreflected by the pointing tool retroreflecting unit 6-1, is transmitted through the surrounding member 6-2 again, and is incident on the light receiving detection unit, and the peak of the light amount is detected. Therefore, in step s110, it is determined that there is an input. Hereinafter, coordinates are calculated from the light amount distribution, and at the same time, a flag of input by the pointing tool is set in step S112. On the other hand, when an instruction is made with a finger, the input is not confirmed in step s110, so it is determined that the input is not made by the pointing tool 6, and the projection wavelength is switched to the first transmission wavelength band in step S113. Since this wavelength band is a transmission band of the light wavelength transmission member 3-2, retroreflected light from the peripheral frame retroreflecting means 3-1 is generated, and a light quantity distribution due to a light-shielding shadow by the finger is detected. At the same time that the designated coordinates are calculated, a finger input flag is set in step s115. According to the third embodiment of the present invention described above, coordinates can be input in both the pointing tool and the finger, and the pointing state can be identified, and this identification information is used as in the conventional example. In the host PC, the cursor type and line type can be changed, and the application can be changed according to the state.

  Although not shown in the flowchart, two transmission wavelength bands corresponding to the bandpass band characteristics of the first transmission wavelength band of the light wavelength transmission member and the second transmission wavelength band of the peripheral member 6-2 by the light projecting means. The light is alternately projected, and the presence / absence of an instruction by the finger is determined as described above. In addition, when the light of the first transmission wavelength band is projected, the light shielding shadow as described above is applied in the case of the finger. In addition to being detected, the surrounding member 6-2 does not transmit even when instructed by the pointing tool, so that the shading shadow at the tip of the pointing tool is detected. Therefore, in the case of the input of the pointing tool, the light quantity distribution between the shading shadow of the surrounding member 6-2 and the retroreflected light of the pointing tool retroreflecting unit 6-1 in each of the first and second transmission wavelength bands. By detecting the coordinates by combining the information, the coordinate detection accuracy by the pointing tool can be further improved.

(Fourth embodiment)
Regarding the structure of the pointing tool, the retroreflected light and the shading shadow are as described above in addition to the structure in which the surrounding member 6-2 is provided around the pointing tool retroreflecting portion 6-1 as in the above embodiment. As long as the configuration is detected, a configuration in which only the indicator retroreflecting unit 6-1 has the following characteristics may be used as follows. For example, as shown in FIG. 22, when the pointing device retroreflecting portion 6-1 is formed in a substantially cylindrical shape, the pointing device retroreflecting portion 6-1 having a retroreflective characteristic only for a narrow incident angle may be used. . In other words, the light from the projection light means is retroreflected only with respect to the axial center portion indicated by A in the figure with a small incident angle, and a retroreflective material is attached in a portion away from the central portion. When the incident angle is increased, retroreflection does not occur. On the other hand, the reflected wave from the retroreflection from the peripheral frame retroreflection means 3 is shielded by the width of the indicator in the direction parallel to the coordinate input surface. As shown in FIG. 11B, it is possible to detect the light distribution of the light shielding shadow and the retroreflected light. More preferably, the pointing tool retroreflecting portion is formed in a substantially cylindrical shape, and the incident angle characteristic of the retroreflection with respect to a direction parallel to the coordinate input surface (FIG. B) is a direction perpendicular to the coordinate input surface (FIG. C). If the angle is smaller than the incident angle characteristic of retroreflection, the sufficient retroreflected light can be obtained in the direction perpendicular to the necessary coordinate input surface, and the detection efficiency is improved.

The schematic structure of the coordinate input device which concerns on this invention, and the front-end | tip part of an indicator, and a periphery retroreflection part structure. The block diagram of the reflection means which has a retroreflection surface. The structural example of the light projection means in a sensor unit. The figure which looked at the detection means in a sensor unit from the perpendicular direction with respect to the input surface. A configuration in which the light projecting unit and the detection unit are overlapped to form the sensor unit 1 when viewed from the input surface and the horizontal direction. The relationship between the amount of reflected light and the reflection angle when the retroreflective tape is flat. Retroreflective member with triangular prisms arranged side by side. Block diagram of the control / arithmetic unit. The timing chart of a control signal. The figure which shows light quantity distribution. Light intensity distribution when input is made with an indicator. The figure which shows a light-shielding state. Reflected light quantity distribution diagram. Reflected light quantity distribution diagram. An example of detection after the ratio calculation is finished. The figure which plotted the tan (theta) value with respect to a pixel number. The figure which shows the positional relationship with a screen coordinate. The flowchart which showed the process from data acquisition to coordinate calculation. The figure which shows the transmission wavelength band in a 2nd Example. The figure which shows the transmission wavelength band in a 2nd Example. The flowchart which showed the process from the data acquisition in the 3rd Example to coordinate calculation. The figure which shows a 4th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensor unit 2 Control / arithmetic unit 3-1 Peripheral frame retroreflective member 3-2 Specific wavelength transmission member 5 Coordinate input area 6 Indicator 6-1 Indicator retroreflective part 6-2 Peripheral member

Claims (8)

A plurality of light receiving detection means are provided at the corners of the coordinate input area surface,
A peripheral frame retroreflecting means that recursively reflects incident light provided in a peripheral portion of the coordinate input area; and a light projecting means that projects light onto the peripheral frame retroreflective means;
From a specific light wavelength transmitting member provided on the incident side of the peripheral frame retroreflecting means, and a change in the amount of light from the light projecting means reflected by the peripheral frame retroreflecting means detected by the light receiving detection means And an optical coordinate input for calculating a position coordinate on a coordinate input area surface designated by the pointing tool or the like based on a plurality of derived angle information. A device,
The pointing tool has a pointing tool retroreflective portion and has a width in a direction perpendicular to the axis of the retroreflecting portion that contributes to effective retroreflection of light from the light projecting means in the vicinity of the axial center of the pointing tool. A coordinate input device characterized in that the width in the direction perpendicular to the axis of the light shielding part contributing to light shielding of the reflected light from the peripheral frame retroreflecting means is larger.   In the above-mentioned claim 1, the indicator is an indicator retroreflecting portion retroreflecting the light from the light projecting means at the axial center of the indicator, and around the indicator retroreflecting portion, Providing a peripheral member that shields light in a wavelength band that has passed through a specific light wavelength transmission characteristic member provided on the incident side of the peripheral frame retroreflective means with the light reflected by the peripheral frame retroreflective means. Characteristic coordinate input device.   3. The small incident angle characteristic according to claim 1, wherein the pointing tool retroreflecting portion of the pointing tool is formed in a substantially cylindrical shape, and performs effective retroreflecting on the light from the light projecting means only in the vicinity of the axial center. The coordinate input device characterized by being.   2. The pointing tool retroreflecting portion of the pointing tool according to claim 1, wherein the pointing tool retroreflecting portion is formed in a substantially cylindrical shape, and the incident angle characteristic of retroreflection with respect to a direction parallel to the coordinate input surface is a direction perpendicular to the coordinate input surface. Coordinate input device characterized by being smaller than the incident angle characteristic of retroreflection.   2. The indicator according to claim 1, wherein the indicator is detected based on the light quantity change information of the retroreflected light retroreflected by the indicator retroreflecting unit and the light-shielding shadow by the surrounding members of the indicator detected by the light receiving detector. A coordinate input device comprising means for detecting position coordinates on a coordinate input area surface designated by the above.   In Claim 1, the specific light wavelength transmitting member provided on the incident side of the peripheral frame retroreflecting means has a first transmission wavelength band, and is provided around the indicator retroreflecting portion. The coordinate input device, wherein the surrounding member has a second transmission wavelength band, and the second transmission wavelength band has a transmission wavelength band narrower than the first transmission wavelength band.   In Claim 1, the specific light wavelength transmitting member provided on the incident side of the peripheral frame retroreflective means has a first transmission wavelength band, and is provided around the indicator retroreflecting portion. The surrounding member has a second transmission wavelength band, the center wavelength values of the transmission wavelength bands of the first transmission wavelength band and the second transmission wavelength band are different, and the light projecting means and the light receiving means The wavelength band includes a first wavelength band and a second wavelength band described above.   8. The specific light provided on the incident side of the peripheral frame retroreflecting means according to claim 7, further comprising means for switching light emission of the first wavelength band and the second wavelength band of the light projecting means. The wavelength transmitting member has means for discriminating between the instruction by the pointing tool and the instruction by the finger by utilizing the fact that the light is retroreflected when emitting light in the first wavelength band and is not retroreflected when emitting light in the second wavelength band. Characteristic coordinate input device.

Images