JP2009026111A - Position detection device, electronic apparatus using the same, and position detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive position detection device for detecting a three-dimensional position of an object. <P>SOLUTION: A game machine 1 comprises a pen 2 and a body 3. The pen 2 is moved by a user as a controller to control the body 3. A three-dimensional position of the pen 2 is detected and the control is based on the position information. A first ultrasonic receiver 5 reflects therein part of ultrasonic waves. First and second ultrasonic receivers 5 and 6 receive reflected waves from opposite directions, and the second ultrasonic receiver 6 detects the incident angle of ultrasonic waves incident in the opposite direction to those on the first ultrasonic receiver 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a position detection device that detects the position of a moving body when a stationary body receives sound waves emitted from the moving body, an electric device using the position detection method, and a position detection method.

  Many devices are used in which a user moves a moving body, a signal is generated according to position information of the moving body, and the fixed body performs various controls in accordance with the signal. For example, in an electronic pen, a user moves a small pen serving as a moving body, and a personal computer serving as a stationary body recognizes the position information and performs control according to the position information. As a result, if the user moves the electronic pen in the same manner as writing characters and figures on paper, characters and figures can be generated on the personal computer by the movements. Further, in the game machine, the user moves the controller serving as the moving body, so that the game machine body serving as the fixed body detects the position and performs various controls accordingly.

  In these, ultrasonic waves are used to detect position information of the moving body. At the same time, light (infrared rays) may be used. That is, the mobile body transmits ultrasonic waves and infrared rays, and these are received by an ultrasonic receiver and an infrared receiver provided on the fixed body, and the position of the mobile body is calculated from the signals. Here, if there are a plurality of ultrasonic receivers in the fixed body, the position of the moving body can be calculated from the difference in the reception timing of the ultrasonic waves between them. In addition, the speed of light is much faster than the speed of sound, and infrared rays can be considered to have arrived instantaneously. Therefore, the received infrared rays are used as a reference signal, and the arrival time of signals received by ultrasonic waves is compared to move with the ultrasonic receiver. The distance of the body can be calculated. By using this, the position of the moving body can be detected.

  For example, Patent Document 1 includes a configuration including an electronic pen (an object to be detected) including an ultrasonic transmitter and an infrared sensor, and a main body (a fixed body) including two ultrasonic receivers and one infrared transmitter. Is described. In this configuration, when the main body transmits infrared light and the electronic pen receives it, it transmits ultrasonic waves, which are received by the two ultrasonic sensors of the main body, and the timing of infrared transmission and the reception of two ultrasonic waves The position on the two-dimensional plane is detected from the difference in timing at which the signal is received.

  Patent Document 2 describes a configuration in which ultrasonic receivers are provided at four corners of a fixed body, and the position of an electronic pen that emits ultrasonic waves is detected from these received signals.

With these configurations, the position of the detected object that emits ultrasonic waves can be recognized in a non-contact manner by the fixed body, and various controls can be performed according to the position information. Thereby, an electronic pen and a game machine could be made to function using this ultrasonic position input device.
JP 2004-102896 A JP-A-2005-300504

  However, in order to detect the three-dimensional position of the detection object using ultrasonic waves, many ultrasonic receivers are required for the fixed body. For example, in the technique described in Patent Document 1, since there are two ultrasonic detectors, the fixed body can detect only the position on the plane of the detected object. Therefore, although it was effective when used for an electronic pen for drawing characters and figures, it was impossible to detect the position of the detected object in three dimensions.

  On the other hand, in the technique described in Patent Document 2, a position in three dimensions can be detected, but four ultrasonic receivers are required. In general, ultrasonic receivers are expensive and account for a high percentage of equipment costs. Therefore, a large number of ultrasonic receivers are required, and the price of the entire apparatus is increased.

  Therefore, it has been difficult to obtain an ultrasonic position detection apparatus that can detect the three-dimensional position of the detection object at a low price.

  The present invention has been made in view of the above problems, and an object thereof is to provide an ultrasonic position detection apparatus and a position detection method that solve the above-described problems.

In order to solve the above problems, the present invention has the following configurations.
The gist of the invention described in claim 1 is a position detection device that detects a position in a three-dimensional position of a detected object on a fixed body separated from the detected object, and is incorporated in the detected object, An electromagnetic wave transmitter that emits an electromagnetic wave modulated by a transmission wave; a sound wave transmitter that emits a sound wave that is modulated by a second transmission wave; and a wave that is modulated by a second transmission wave; An electromagnetic wave receiver for demodulating and a sound wave receiver which is incorporated in the fixed body and receives the sound wave and converts it into an electric signal is fixed to a mounting base made of a sound wave absorber through a support, The position detecting apparatus includes a first and a second sound wave receiver having a structure in which a reflection plate for reflecting the sound wave is provided in part.
The gist of the invention described in claim 2 is the installation direction of the reflector as seen from the sound wave receiver in the first sound wave receiver, and the reflection plate as seen from the sound wave receiver in the second sound wave receiver. The position detecting device according to claim 1, wherein the position detecting device is substantially opposite to the installation direction.
The gist of the invention described in claim 3 resides in the position detection device according to claim 1 or 2, wherein the first transmission wave and the second transmission wave have the same waveform.
The gist of the invention of claim 4 resides in the position detection device according to any one of claims 1 to 3, wherein the second transmission wave is a random signal.
The gist of the invention described in claim 5 resides in the position detection device according to claim 4, wherein the random signal is composed of an M-sequence bit pattern.
The gist of the invention described in claim 6 is that an autocorrelation function of the first and / or second received sound wave generated by the first and / or second sound wave receiver receiving and demodulating the sound wave is obtained. 6. The apparatus according to claim 1, further comprising a control unit that calculates an incident angle of the sound wave incident on the first and / or second sound wave receiver by calculation. It exists in the position detection apparatus of description.
The gist of the invention according to claim 7 is that the control unit calculates a cross-correlation function between the first sound wave reception wave and the second sound wave reception wave, so that the first sound wave receiver of the sound wave is obtained. The position detection device according to claim 6, wherein the difference between the reception time of the sound wave and the reception time of the sound wave to the second sound wave receiver is calculated.
The gist of the invention according to claim 8 is that the control unit has a cross-correlation function between the first and / or second acoustic wave reception wave and the electromagnetic wave reception wave generated by demodulating the electromagnetic wave by the electromagnetic wave receiver. The position detecting apparatus according to claim 6 or 7, wherein a distance from the detected object to the first and / or second acoustic wave receiver is calculated by calculating.
The gist of the invention described in claim 9 resides in the position detection device according to any one of claims 1 to 8, wherein the electromagnetic wave is infrared rays.
The gist of the invention described in claim 10 resides in the position detecting device according to any one of claims 1 to 9, wherein the sound wave is an ultrasonic wave.
The gist of the invention described in claim 11 resides in an electrical apparatus characterized by using the position detection device described in any one of claims 1 to 10.
The gist of the invention described in claim 12 is that a position in a three-dimensional position of a detected object including an electromagnetic wave transmitter that emits electromagnetic waves and a sound wave transmitter that emits sound waves is separated from the detected object and receives the electromagnetic waves. A position detection method for detecting in a fixed body comprising an electromagnetic wave receiver and first and second sound wave receivers for receiving the sound wave, wherein the incident light is incident on the first and second sound wave receivers. A reflection plate that receives a reflected wave that reflects a sound wave is provided in part, and the time when the electromagnetic wave reaches the electromagnetic wave receiver and the time when the sound wave reaches the first and / or second sound wave receiver A distance calculating step of calculating a distance between the detected object and the first and / or second sound wave receiver, a time when the sound wave reaches the first sound wave receiver, and the sound wave Reaching the second acoustic wave receiver A receiver direction position calculating step of calculating a position of the detected object in a direction connecting the first sound wave receiver and the second sound wave receiver based on a difference in time; and the first and second sound waves A sound wave direction calculating step of calculating an incident angle of the sound wave to the first and / or second sound wave receiver by analyzing a signal received by the receiver, and the detected object and the first A distance from the first and / or second sound wave receiver, a position of the detected object in a direction connecting the first sound wave receiver and the second sound wave receiver, and the first and / or second sound wave A position calculating step of calculating a position of the detected object in three dimensions from the incident angle of the sound wave to the sound wave receiver.
The gist of the invention described in claim 13 is that the direction of the reflected wave received by the first sound wave receiver is substantially opposite to the direction of the reflected wave received by the second sound wave receiver. It exists in the position detection method of Claim 12 characterized by the above-mentioned.
The gist of the invention described in claim 14 is that the electromagnetic wave transmitter emits the electromagnetic wave modulated by a first transmission wave, and the acoustic wave transmitter emits the sound wave modulated by a second transmission wave, and the electromagnetic wave. The receiver receives and demodulates the electromagnetic wave to generate an electromagnetic wave reception wave, and the first and second sound wave receivers receive and demodulate the sound wave to demodulate the first and second sound wave reception waves. 14. The position detection method according to claim 12 or claim 13, wherein:
The gist of the invention of claim 15 is characterized in that, in the sound wave direction calculating step, the incident angle of the sound wave is calculated from the peak position in the autocorrelation function of the first and / or second sound wave reception waves. The present invention resides in the position detection method according to claim 14.
The gist of the invention described in claim 16 is that, in the distance calculating step, the detected object and the first are determined from a peak position in a cross-correlation function of the electromagnetic wave reception wave and the first and / or second sound wave reception wave. The distance detection method according to claim 14 or 15, wherein the distance from the second acoustic wave receiver is calculated.
The gist of the invention described in claim 17 is that, in the receiver direction position calculating step, the difference between the arrival times from the peak position in the cross-correlation function between the first sound wave reception wave and the second sound wave reception wave. The position detection method according to any one of claims 14 to 16, wherein the position detection method calculates the position.
The gist of the invention according to claim 18 is the position according to any one of claims 14 to 17, wherein the first transmission wave and the second transmission wave have the same waveform. It exists in the detection method.
The gist of the invention described in claim 19 resides in the position detection method according to any one of claims 14 to 18, wherein the second transmission wave is a random signal.
The gist of the invention described in claim 20 resides in the position detection method according to claim 19, characterized in that the random signal comprises an M-sequence bit pattern.
The gist of the invention described in claim 21 resides in the position detection method according to any one of claims 12 to 20, wherein the electromagnetic wave is infrared rays.
The gist of the invention described in claim 22 resides in the position detection method according to any one of claims 12 to 21, wherein the sound wave is an ultrasonic wave.

  ADVANTAGE OF THE INVENTION According to this invention, the position detection apparatus and electric equipment which can detect the position in the three dimensions of a to-be-detected body can be obtained at low cost.

(First embodiment)
FIG. 1 is a diagram showing a configuration of a game machine 1 in which a position detection device according to a first embodiment of the present invention is incorporated. Here, the game machine 1 includes a pen 2 and a main body 3. The user controls the main body 3 by moving the pen 2 as a controller. At this time, the position of the pen 2 in the three dimensions is detected, and this control is performed based on the position information. Here, the constituent elements of the position detection device are an ultrasonic (sound wave) transmitter 21, an infrared (electromagnetic wave) transmitter 22 incorporated in the pen 2 as a detection target, and a fixed body. The first and second ultrasonic (sound wave) receivers 5 and 6, the infrared (electromagnetic wave) receiver 7 in the main body 3, and a control unit to be described later.

  The pen 2 is provided with an ultrasonic (sound wave) transmitter 21 and an infrared (electromagnetic wave) transmitter 22, which transmit ultrasonic waves and infrared rays, respectively. The ultrasonic transmitter 21 is composed of a piezoelectric material such as PVDF and an electrode, and emits an ultrasonic wave corresponding to an input AC signal, for example, an ultrasonic wave of 40 kHz. However, it is not restricted to the sound wave of this frequency, The sound wave of arbitrary frequencies can be used. The infrared transmitter 22 is composed of an LED (light emitting diode) and transmits infrared rays. Similarly, the present invention is not limited to infrared rays having this wavelength, and electromagnetic waves having an arbitrary wavelength can be used. Further, the ultrasonic transmitter 21 and the infrared transmitter 22 modulate ultrasonic waves and infrared rays with a predetermined transmission wave and output them.

  Therefore, the pen 2 has a function for outputting such a signal. FIG. 2 shows a configuration of the pen 2. The transmission wave is generated by the trigger generation unit 23. The transmission wave generated here is, for example, an M-sequence bit pattern, that is, a signal in which binary values “1” and “0” appear randomly. In the transmission waveform forming unit 24, a signal after the alternating current (for example, 40 kHz) that drives the ultrasonic transmitter 21 is modulated (for example, phase modulated) by this transmission wave is input to the output amplifier 25. The amplified signal is input to the ultrasonic transmitter 21 and ultrasonic waves are transmitted in response thereto. The transmission wave generated by the trigger generation unit 23 is also input to the infrared pattern generation unit 26 at the same time, and the infrared light emitted from the infrared transmitter 22 is modulated by this transmission wave and output. The trigger generating unit 23, the transmission waveform forming unit 24, and the infrared pattern generating unit 26 may be integrally formed as a device having these functions and controlled by a computer. In this position detecting device, there are many places where infrared rays are reflected, and even if there is a difference in arrival time of infrared rays reflected at each place, the difference can be ignored. In addition, even if there are other devices that use infrared rays, transmission waves that modulate infrared rays can be used as long as they can recognize the arrival time of infrared rays without causing interference with the position detection device. The waveform of the transmission wave (second transmission wave) for modulating the ultrasonic wave may be different from the waveform of the first transmission wave). In particular, the first transmission wave may be a simpler pattern, for example, a one-pulse pattern.

  In the main body 3, ultrasonic receivers 5 and 6 are disposed on the left and right of the display 4, and an infrared receiver 7 is disposed on the upper side. These receive ultrasonic waves and infrared rays transmitted as described above. It should be noted that the ultrasonic transmitter 21 and the infrared transmitter 22 in the pen 2 are of a size that can be regarded as a point source that emits ultrasonic waves and infrared rays. It is assumed that the emitted ultrasonic waves and infrared rays reach the main body 3.

  The figure which shows the structure of the 1st ultrasonic receiver 5 is Fig.3 (a) (b). 3A is a view of the ultrasonic receiver 5 as viewed from the front, that is, from the front of the display 4, and FIG. 3B is a view as viewed from the side (the right side of the display 4). In this ultrasonic receiver 5, the ultrasonic receiver 51 receives the ultrasonic wave, converts it into an electric signal, and outputs it. The ultrasonic receiver 51 is fixed to the mounting base 53 via the support column 52 and is fixed to the display 4. Here, as shown in FIG. 3A, the ultrasonic receiver 51 has a disk shape, and the mounting base 53 has a larger disk shape. However, a reflective plate 54 is provided on a part of the mounting base 53 (the lower side in FIG. 3). Here, it is assumed that A and B and C and D are emitted from the same ultrasonic transmitter 21. In the first ultrasonic receiver 5, a part of the ultrasonic wave is reflected inside. By receiving this reflected wave, the incident angle of the received ultrasonic wave can be detected.

  Similar to the ultrasonic transmitter 21, the ultrasonic receiver 51 includes, for example, a thin plate-shaped piezoelectric film and electrodes. The ultrasonic receiver 51 converts the received ultrasonic wave into an electric signal. Further, when the ultrasonic receiver 51 receives ultrasonic waves, there is no directivity. In FIG. 3B, both ultrasonic waves incident from the left side and ultrasonic waves incident from the right side are received. be able to.

  The mounting base 53 is composed of a sound absorber that absorbs ultrasonic waves, such as rubber and sponge. Therefore, the ultrasonic wave (D) incident on the mounting base 53 is absorbed without being reflected.

  Conversely, the reflecting plate 54 is made of a material that reflects ultrasonic waves, such as a metal plate. Therefore, the ultrasonic wave incident on the reflecting plate 54 is reflected thereby.

  Here, if the pen 2 (ultrasonic transmitter 21) is sufficiently small, it can be regarded as a point source. Therefore, in order to detect the position, it is necessary to detect the incident angle of the ultrasonic wave received by the ultrasonic receiver 51. is there.

  In the above configuration, as shown in FIG. 3B, the ultrasonic wave received by the ultrasonic receiver 51 includes the ultrasonic wave (A) emitted from the pen 2 and directly incident on the ultrasonic receiver 51. , There is an ultrasonic wave (B) emitted from the pen 2 and once reflected by the reflecting plate 54 and then incident on the ultrasonic receiver 51. As shown in FIG. 3B, the incident angle of the ultrasonic wave viewed from the vertical direction of the surface of the display 4 is θ. Since the ultrasonic waves of the A path and the ultrasonic waves of the B path are both transmitted from the same ultrasonic transmitter 21, strictly speaking, θ is different between A and B, but the pen 2 (ultrasonic wave) If the distance between the transmitter 21) and the ultrasonic receiver 51 is sufficiently larger than the size of the ultrasonic receiver 5 (the length in the vertical direction in FIG. 3B), θ is equal to A and B. Can be considered equal.

  As shown in FIG. 3B, since the ultrasonic wave of the route B is longer than the ultrasonic wave of the route A, even if the ultrasonic wave of the route A is emitted from the pen 2 at the same time, It arrives later than the ultrasound. This delay time depends on θ. That is, when θ is small (close to 0 degree), the delay time is short, and when θ is large (close to 90 degrees), the delay time is large. Therefore, if the delay time of the reflected wave is detected, θ can be calculated.

  A method for calculating the delay time of the reflected wave will be described below. FIG. 4 is a conceptual diagram showing this method. As described above, the received ultrasonic wave is modulated with a random signal, and a signal (received wave) obtained by demodulating it is this random signal. As shown in FIG. 4, the received wave (direct wave) after passing through the path A and the received wave (reflected wave) after passing through the path B are random waveforms having a similar relationship. The reflected wave reaches the ultrasonic receiver 51 with a delay from the direct wave. However, in actuality, the ultrasonic wave receiver 51 receives both the ultrasonic waves of both paths without any distinction, is converted into an electric signal, and is detected as a received wave. Therefore, as shown in the lower part of FIG. 4, when the autocorrelation function of the detected received wave is calculated, this autocorrelation function takes a maximum value when the delay time is zero, but is strong also at the delay time of the reflected wave. A correlation appears and a corresponding peak is obtained. Here, if there are periodic components in the received wave (transmitted wave), multiple peaks may occur. By making the transmitted wave random, other peaks are less likely to appear, and the clarity of this peak is reduced. Can be increased.

  This delay time is minimized when θ is 0 °, and the value is determined by the height of the support column 52 (the left and right length I in FIG. 3B). If I is small and the minimum delay time is too short, the absolute value of the detected delay time becomes small, and thus detection becomes difficult. Also. If I is large and the minimum delay time is large, even if the ultrasonic signal is random, the peak of the autocorrelation function becomes relatively small, and it becomes difficult to determine the delay time.

  A distance difference corresponding to this delay time (a value obtained by multiplying the delay time by the speed of sound) is 2 × I × cos (θ). Assuming that the maximum effective detection angle is 30 °, this distance difference fluctuates in the range of 2I to √ (3) × I. For example, when an ultrasonic wave having a frequency of 40 kHz is used, its wavelength in the atmosphere is about 8 mm. When the ultrasonic wave is modulated with the M-sequence bit pattern, in order to easily detect the delay time with the autocorrelation function, the distance corresponding to the minimum delay time is preferably about 5 wavelengths or more. Since the minimum value of this distance difference is √ (3) × I, the minimum value of I is about 23 mm.

  If the area of the reflecting plate 54 is too small, the intensity of the reflected wave received by the ultrasonic receiver 51 becomes small, so that it is difficult to detect the peak. Therefore, it is preferable that the size of the reflection plate 54 is at least about three wavelengths, and is about 24 mm when a 40 kHz ultrasonic wave is used.

  Further, for example, when the game machine 1 is used, since the ultrasonic wave emitted from the pen 2 is reflected by various places other than the reflector 54 and then received by the ultrasonic receiver 51, the reflection by this is reflected. Waves will also appear in the autocorrelation function. However, the distance difference due to such an unintended reflected wave is several cm or more, for example, 10 cm or more, and thus is larger than the distance difference caused by the reflecting plate 54. Accordingly, although a plurality of peaks occur in the autocorrelation function in the lower part of FIG. 4, the peak at the shortest time (greater than zero) is generated by the reflector 54, and the peak time is delayed. It will be time.

  For example, in the game machine 1, when playing a music performance game using the pen 2 as a conductor, if the length of the conductor (pen 2) is made sufficiently larger than the minimum value of the distance difference, the reflected wave The delay time caused by 54 can be easily detected. For example, the length of the baton may be 30 cm.

  However, as is apparent from FIG. 3B, the ultrasonic receiver 51 is incident from the horizontal direction in FIG. 3 on the lower side, that is, the direction (A, B) on the side where the reflecting plate 54 is provided. Ultrasonic waves and direct waves (C) incident from the opposite side can be received, but reflected waves (D) incident from the opposite side cannot be received. Therefore, assuming that θ in FIG. 3B is a positive direction, the ultrasonic receiver 5 can detect only a positive value θ.

  Here, the second ultrasonic receiver 6 has the same configuration as that of the first ultrasonic receiver 5, but the installation direction of the reflection plate 64 with respect to the ultrasonic receiver is set in the direction of the first ultrasonic receiver 5. Reverse the case. That is, as shown in FIG. 5, the configuration of the main body 3 at this time is such that, in the first ultrasonic receiver 5 on the left side, the reflecting plate 54 is on the lower side and on the second ultrasonic receiver 6 on the right side. The reflector 64 is provided on the upper side. Thereby, in the 1st, 2nd ultrasonic receivers 5 and 6, the direction of the reflected wave to receive is a mutually reverse direction, and the 2nd ultrasonic receiver 6 is the 1st ultrasonic receiver. The incident angle of the ultrasonic wave incident from the opposite direction to that in the case of 5 can be detected. Therefore, positive θ is detected by the first ultrasonic receiver 5 and negative θ is detected by the second ultrasonic receiver 6. Therefore, the incident angle θ of the ultrasonic wave from the vertical direction of the surface of the display 4 can be detected by the first or second ultrasonic receiver 5 or 6. There will be a pen 2 in the direction of this angle in the vertical direction. When the position range where the pen 2 exists is limited in advance and θ can take only a positive or negative value, the autocorrelation function may be calculated for only one of them.

  On the other hand, the position of the pen 2 in FIG. 1 in the horizontal direction and the distance from the first and second ultrasonic receivers 5 and 6 to the pen 2 are calculated in the same manner as described in Patent Document 1.

  That is, the position of the pen 2 in the horizontal direction can be obtained by analyzing a shift in reception timing of random signals received by the first and second ultrasonic receivers 5 and 6. For example, if the cross-correlation function of the received waves in the first and second ultrasonic receivers 5 and 6 is calculated, the difference in the arrival time of the ultrasonic wave between them from the peak position in the same manner as in FIG. Can be calculated. The pen 2 is present on the side of the ultrasonic receiver that previously received the ultrasonic wave in the horizontal direction, and the horizontal position can be calculated from this.

  In addition, as shown in FIG. 2, when the infrared signal emitted from the infrared transmitter 22 and the ultrasonic signal are modulated with a transmission wave having the same waveform (the first transmission wave and the second transmission wave have the same waveform). In this case, the infrared wave received by demodulating the signal received by the infrared receiver 7 has a random waveform similar to the direct wave received by the ultrasonic receivers 5 and 6. Therefore, if the cross-correlation function between this infrared wave and the wave received by the ultrasonic receivers 5 and / or 6 is calculated, the difference in arrival time between them can be obtained in the same manner as in FIG. Since the speed of light is significantly greater than the speed of sound and infrared light can be considered to have arrived at the infrared receiver 7 instantaneously from the infrared transmitter 22, even if the infrared signal and the ultrasonic signal are not modulated with the same wave transmission wave, these The distance from the pen 2 to the ultrasonic receivers 5 and / or 6 can be calculated from the difference in arrival time between them. In this case, the position of the infrared receiver 7 is not particularly limited as long as it is in the vicinity of the display 4.

  Accordingly, the vertical angle at which the pen 2 exists as viewed from the main body 3, the position of the pen 2 in the horizontal direction, and the distance to the pen 2 are determined by the first and second ultrasonic receivers 5 and 6 and the infrared reception. It can be calculated by analyzing the received wave of the device 7. Thereby, the position in three dimensions of the pen 2 can be calculated.

  In addition, arrangement | positioning of the 1st, 2nd ultrasonic receivers 5 and 6 can also be set as structures other than FIG. For example, the configuration shown in FIG. In this case, the first ultrasonic receiver 5 is provided on the upper side of the display 4 and the reflection plate 54 is provided on the right side thereof. The second ultrasonic receiver 6 is provided on the lower side of the display 4 and the reflection plate 64 is provided on the left side thereof. In this case, the horizontal angle at which the pen 2 exists is calculated using the first and second ultrasonic receivers 5 and 6 by the method shown in FIG. Further, the position of the pen 2 in the vertical direction is calculated by analyzing the cross-correlation function of the received waves of the first and second ultrasonic receivers 5 and 6. Accordingly, the position of the pen 2 in the three dimensions can be calculated as described above.

  This position calculation is performed in the main body 3. For this reason, the main body 3 has a control unit composed of a microcomputer or the like, and performs an analysis using an infrared reception wave and two ultrasonic reception waves. FIG. 7 is a flowchart showing this operation. In addition, the structure of the main body 3 used here shall be what was shown in FIG. 1, FIG. However, the ultrasonic receivers 5 and 6 and the infrared receiver 7 need to be provided in the main body 3, but this control unit does not necessarily have to be provided in the main body 3. May be provided separately.

  First, the control unit determines whether infrared rays and ultrasonic waves are received with reference to the infrared receiver 7 and the ultrasonic receivers 5 and 6 (S1). If these are not received, it is determined that the pen 2 is not operating or the pen 2 is out of the detection range, and waits until it is received.

If they had been detected, the detection time and t _1, the control unit calculates the cross-correlation function between them (S2). That is, the infrared reception wave obtained by demodulating the infrared ray received by the infrared receiver 7 and the ultrasonic reception wave obtained by demodulating the ultrasonic wave received by the ultrasonic receiver 5 (first ultrasonic reception) The cross-correlation function (first cross-correlation function) with the wave is calculated. At the same time, a cross-correlation function (second cross-correlation function) between the infrared reception wave and the ultrasonic reception wave (second ultrasonic reception wave) obtained by demodulating the ultrasonic wave received by the ultrasonic receiver 6 ) Is also calculated. Here, the infrared reception wave and the first and second ultrasonic reception waves used for these processes are stored in, for example, a first-in first-out (FIFO) type memory as time-series data within a predetermined time T before t _1. Has been. This length T needs to be equal to or greater than the bit length of the pseudo random pattern in the M-sequence bit pattern. Specifically, the first cross-correlation function C _IU1 (τ) and the second cross-correlation function C _IU2 (τ) are the infrared reception wave I (t) and the first ultrasonic reception wave U ₁ (t). Using the second ultrasonic reception wave U ₂ (t), the following equation is used.

  Here, the integration is performed on data within a predetermined time T stored in the memory.

Next, in the cross-correlation function calculated above, it is determined whether or not there is a point where a strong correlation is found (S3). Specifically, if there is a point exceeding a preset threshold in the values of the first cross-correlation function C _IU1 (τ) and the second cross-correlation function C _IU2 (τ), a strong correlation is obtained. Judge that there was. Alternatively, this determination may be performed based on the rate of change of C _IU1 (τ) and C _IU2 (τ). If a strong correlation is not recognized, the first ultrasonic reception wave U ₁ (t) and the second ultrasonic reception wave U ₂ (t) are newly sampled, and the process of S2 is performed again.

When a strong correlation is recognized, the distance in the front-rear direction from the pen 2 to the first and second ultrasonic receivers 5 and 6 is calculated from C _IU1 (τ) and C _IU2 (τ) (S4). : Distance calculation step). Specifically, C _IU1 (τ) is the delay time in the first ultrasonic wave receiver 5 from the value of tau has a peak in, C _IU2 (τ) second ultrasonic receiving from the value of tau has a peak in The delay time in the device 6 is calculated. A value obtained by multiplying these delay times by the speed of sound (about 340 m / s in the atmosphere) is the distance in the front-rear direction from the pen 2 to the first and second ultrasonic receivers 5 and 6. That is, in this distance calculation step, the difference between the time when the infrared rays reach the infrared receiver 7 and the time when the ultrasonic waves reach the first and second ultrasonic receivers 5 and 6 is determined based on the difference between the pen 2 and the first time. The distance from the second ultrasonic receivers 5 and 6 is calculated.

Next, a cross-correlation function C _U1U2 (τ) between the two ultrasonic receivers 5 and 6 is calculated (S5). Specifically, C _U1U2 (τ) is calculated by the following equation.

Here, the integration range is the same as C _IU1 (τ) and C _IU2 (τ).

Next, it is determined whether or not there is a point where strong correlation is found in the cross-correlation function C _U1U2 (τ) (S6). This method is the same as the case of S3 performed for C _IU1 (τ) and C _IU2 (τ). If a strong correlation is not recognized, the first ultrasonic reception wave U ₁ (t) and the second ultrasonic reception wave U ₂ (t) are newly sampled, and the process of S5 is performed again.

When a strong correlation is recognized, C _U1U2 (τ), the difference between the arrival times of the ultrasonic waves in the first and second ultrasonic receivers 5 and 6 is calculated, and thereby the first and second The position of the pen 2 in the direction connecting the ultrasonic receivers 5 and 6 (in this case, the horizontal direction) is calculated (S7: receiver direction position calculating step). That is, in this receiver direction position calculation step, the first time is determined by the difference between the time when the ultrasonic wave reaches the first ultrasonic receiver 5 and the time when the ultrasonic wave reaches the second ultrasonic receiver 6. The position of the pen 2 in the direction connecting the ultrasonic receiver 5 and the second ultrasonic receiver 6 is calculated.

Next, the autocorrelation functions C _U1 (τ) and C _U2 (τ) in the received waves of the first and second ultrasonic receivers 5 and 6 are calculated (S8). Specifically, C _U1 (τ) and C _U2 (τ) are calculated by the following equations.

Next, in these autocorrelation functions C _U1 (τ) and C _U2 (τ), it is determined whether or not there is a point where a clear peak is seen (S9). This method is the same as the case of S3 performed for C _IU1 (τ) and C _IU2 (τ). If a clear peak is not recognized, the first ultrasonic reception wave U ₁ (t) and the second ultrasonic reception wave U ₂ (t) are newly sampled, and the process of S8 is performed again.

When a clear peak is recognized in either C _U1 (τ) or C _U2 (τ), the delay time in the first and second ultrasonic receivers 5 and 6 is calculated from the position of this peak. Then, the incident angle θ of the ultrasonic wave in the vertical direction is calculated by the above method (S10: sound wave direction calculating step). That is, in this sound wave direction calculation step, the first and second ultrasonic receivers 5 and 6 analyze the signals received by the sound waves, thereby supplying the first and second ultrasonic receivers 5 and 6 to the sound wave direction calculation step. The incident angle of the sound wave is calculated.

  By the above method, the distance between the pen 2 and the first and second ultrasonic receivers 5 and 6, the position of the pen 2 in the horizontal direction, and the pen viewed from the first and second ultrasonic receivers 5 and 6. An angle of 2 in the vertical direction is calculated. As a result, the position of the pen 2 in the three dimensions is calculated (S11: position calculation step). That is, in this position calculation step, the distance between the pen 2 and the first and second ultrasonic receivers 5 and 6 and the direction connecting the first ultrasonic receiver 5 and the second ultrasonic receiver 6 are determined. The position of the pen 2 in the three dimensions is calculated from the position of the pen 2 and the incident angle of the sound wave to the first and second ultrasonic receivers 5 and 6.

  In addition, since strong correlation was not recognized in S3 and S6, you may provide a time-out process when sampling an ultrasonic reception wave newly. In this case, when the time when no strong correlation is recognized passes a predetermined time, the setting is made so that the processing is performed again from the reception of the infrared signal (S1). The same applies to the case where no clear peak was observed in S9. Thereby, it is possible to detect the position of the pen 2 more accurately.

  In the above embodiment, the position of the pen 2 in the three dimensions is detected by one infrared receiver and two ultrasonic receivers. This is made possible by providing a reflection plate in a part of each ultrasonic receiver and detecting the incident angle of the ultrasonic wave by the above method.

  As shown in FIG. 3, each ultrasonic receiver has a simple structure in which a column 52 and a reflector 54 are provided in a conventional ultrasonic receiver. Therefore, these are easy to manufacture, and their manufacturing costs are not significantly different from those of conventional ultrasonic receivers. Therefore, it is possible to obtain a position detection device capable of detecting the position of the moving body in the three dimensions and an electric device using the position detection device at a low price.

  However, in order to perform position detection more accurately, a configuration using three or more ultrasonic receivers having the same structure may be used. In this case, the cost is higher than in the above embodiment, but more accurate position detection than in the above embodiment is possible.

  In the above example, the transmission wave that modulates infrared rays and ultrasonic waves is composed of random signals, but is not limited thereto. The delay times in the first and second ultrasonic reception waves shown in FIG. 4, the difference in arrival time between the first ultrasonic receiver and the second ultrasonic receiver, and the first and second from the infrared reception wave Any transmission wave having an arbitrary waveform can be used as long as it becomes a reference for detecting a difference in arrival time from the ultrasonic reception wave.

  In the above example, the position input device is incorporated in a game machine and detects the position of the pen. However, the present invention is not limited to this. Similarly, any device that emits ultrasonic waves and infrared rays can be used instead of a pen. For example, it is possible to detect the positions in the three dimensions of the mouse and various controllers in the same manner. Further, the present invention is not limited to a game machine, and can be used by being incorporated into a general personal computer or various electric devices that are remotely operated.

  In the above example, infrared rays and ultrasonic waves are used for position detection. However, the present invention is not limited to these. Any device can be used in the same manner as long as it can emit light from a pen (object to be detected), can modulate a transmission wave, and can be received by a detector in the main body. For example, an arbitrary electromagnetic wave, for example, an electromagnetic wave such as a microwave having a longer wavelength can be used instead of infrared rays.

It is a figure which shows the structure of the game machine with which the position detection apparatus used as embodiment of this invention was integrated. It is a figure which shows the structure of the pen used in the game machine with which the position detection apparatus used as embodiment of this invention was integrated. It is a figure which shows the structure of the ultrasonic receiver used for the position detection apparatus used as embodiment of this invention. It is a figure which shows the outline | summary of the method of detecting the incident angle of an ultrasonic wave in the ultrasonic receiver used for the position detection apparatus used as embodiment of this invention. It is a figure which shows an example of a structure of the game machine main body with which the position detection apparatus used as embodiment of this invention was integrated. It is a figure which shows the other example of a structure of the game machine main body with which the position detection apparatus used as embodiment of this invention was integrated. It is a flowchart which shows the position detection method used as embodiment of this invention.

Explanation of symbols

1 Game console 2 Pen (object to be detected)
3 Body (fixed body)
4 Display 5 First Ultrasonic (Sound) Receiver 6 Second Ultrasonic (Sound) Receiver 7 Infrared (Electromagnetic) Receiver 21 Ultrasonic (Sound) Transmitter 22 Infrared (Electromagnetic) Transmitter 23 Trigger Generation Unit 24 Transmission waveform forming unit 25 Output amplifier 26 Infrared pattern generating unit 51 Ultrasonic wave receiver 52 Strut 53 Mounting base 54, 64 Reflector

Claims (22)

A position detection device for detecting a position in a three-dimensional position of a detected object in a fixed body separated from the detected object,
An electromagnetic wave transmitter that is incorporated in the detected object and emits an electromagnetic wave modulated by a first transmission wave;
A sound wave transmitter that is incorporated in the object to be detected and emits a sound wave modulated by a second transmission wave;
An electromagnetic wave receiver that is incorporated in the fixed body and receives and demodulates the electromagnetic wave;
A sound wave receiver, which is incorporated in the fixed body and receives the sound wave and converts it into an electrical signal, is fixed to a mounting base made of a sound wave absorber through a support, and the sound wave is reflected on a part of the mounting base. First and second acoustic wave receivers having a structure provided with a reflector;
A position detection apparatus comprising:   The installation direction of the reflector as viewed from the sound wave receiver in the first sound wave receiver and the installation direction of the reflector as viewed from the sound wave receiver in the second sound wave receiver are substantially opposite. The position detection device according to claim 1.   The position detection device according to claim 1, wherein the first transmission wave and the second transmission wave have the same waveform.   The position detection device according to any one of claims 1 to 3, wherein the second transmission wave includes a random signal.   The position detection apparatus according to claim 4, wherein the random signal includes an M-sequence bit pattern.   By calculating an autocorrelation function of the first and / or second acoustic wave generated by receiving and demodulating the acoustic wave by the first and / or second acoustic wave receiver, The position detection device according to claim 1, further comprising a control unit that calculates an incident angle of the sound wave incident on the second sound wave receiver. The controller is
By calculating the cross-correlation function between the first sound wave reception wave and the second sound wave reception wave, the reception time of the sound wave to the first sound wave receiver and the sound wave to the second sound wave receiver The position detection device according to claim 6, wherein a difference from the reception time is calculated. The controller is
By calculating a cross-correlation function between the first and / or second acoustic wave reception wave and the electromagnetic wave reception wave generated by demodulating the electromagnetic wave by the electromagnetic wave receiver, the first and 8. The position detection apparatus according to claim 6, wherein a distance to the second sound wave receiver is calculated.   The position detecting device according to any one of claims 1 to 8, wherein the electromagnetic wave is an infrared ray.   The position detecting device according to any one of claims 1 to 9, wherein the sound wave is an ultrasonic wave.   An electrical apparatus using the position detection device according to any one of claims 1 to 10. An electromagnetic wave receiver that receives the electromagnetic wave and a position in a three-dimensional position of the detected object that includes the electromagnetic wave transmitter that emits the electromagnetic wave and the sound wave transmitter that emits the sound wave are separated from the detected object. A position detection method for detecting in a stationary body comprising first and second sound wave receivers,
In the first and second sound wave receivers, a reflection plate for receiving a reflected wave reflecting the incident sound wave is provided in part,
Based on the difference between the time when the electromagnetic wave reaches the electromagnetic wave receiver and the time when the sound wave reaches the first and / or second sound wave receiver, the detected object and the first and / or second A distance calculating step for calculating a distance from the sound wave receiver;
Based on the difference between the time when the sound wave reaches the first sound wave receiver and the time when the sound wave reaches the second sound wave receiver, the first sound wave receiver and the second sound wave receiver are A receiver direction position calculating step for calculating a position of the detected object in a connecting direction;
A sound wave direction calculating step of calculating an incident angle of the sound wave to the first and / or second sound wave receiver by analyzing a signal received by the first and second sound wave receivers; ,
A distance between the detected object and the first and / or second acoustic wave receiver, a position of the detected object in a direction connecting the first acoustic wave receiver and the second acoustic wave receiver, and the A position calculating step of calculating a position in three dimensions of the detected object from an incident angle of the sound wave to the first and / or second sound wave receiver;
A position detection method comprising:   The direction of the reflected wave received by the first acoustic wave receiver and the direction of the reflected wave received by the second acoustic wave receiver are substantially opposite to each other. The position detection method described. The electromagnetic wave transmitter emits the electromagnetic wave modulated by a first transmission wave,
The sound wave transmitter emits the sound wave modulated by a second transmission wave,
The electromagnetic wave receiver receives and demodulates the electromagnetic wave to generate an electromagnetic wave reception wave,
14. The position detection according to claim 12, wherein the first and second sound wave receivers receive and demodulate the sound wave to generate first and second sound wave reception waves. Method. In the sound wave direction calculation step,
The position detection method according to claim 14, wherein an incident angle of the sound wave is calculated from a peak position in an autocorrelation function of the first and / or second sound wave reception wave. In the distance calculating step,
Calculating a distance between the detected object and the first and / or second acoustic wave receiver from a peak position in a cross-correlation function between the electromagnetic wave reception wave and the first and / or second acoustic wave reception wave; The position detection method according to claim 14 or 15, wherein: In the receiver direction position calculating step,
The difference between the arrival times is calculated from the peak position in the cross-correlation function between the first sound wave reception wave and the second sound wave reception wave. 2. The position detection method according to item 1.   The position detection method according to claim 14, wherein the first transmission wave and the second transmission wave have the same waveform.   The position detection method according to claim 14, wherein the second transmission wave is a random signal.   The position detection method according to claim 19, wherein the random signal includes an M-sequence bit pattern.   The position detection method according to any one of claims 12 to 20, wherein the electromagnetic wave is an infrared ray. The position detection method according to any one of claims 12 to 21, wherein the sound wave is an ultrasonic wave.

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