JP2007127475A - Light-wave distance meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform non-prism measurement and prism measurement by only using the means for splitting the light of different wave length into distance measurement light and reference light for a mechanical moving part. <P>SOLUTION: During non-prism measurement, the light of the visible laser diode 12a is emitted to the target and the optical fiber 20 through the dichroic mirrors 22, 30, and the reflection mirror 32, 34. In prism measurement, the light of infrared light laser diode 12b is introduced into the dichroic mirror 22 so as to reflect to the optical fiber 26 side, and the light diverged by the fiber 26 is emitted to the reflection prism 58 and the optical fiber 20 from the dichroic mirror 30 through the reflection mirrors 32 and 34. The reflection light from the target or the reference light from the optical fiber 20 is converted into the distance measurement signal or the reference signal by a light-receiving diode 42. The distance to the target is obtained based on the phase difference between both the signals. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention transmits distance measuring light whose intensity is modulated by a modulation signal to the measurement optical path and the reference optical path, and compares the reflected light reflected by the target on the measurement optical path and the light from the reference optical path. The present invention relates to a light wave rangefinder that can determine the distance to a target.

  As a light wave distance meter, for example, the distance to the target is obtained based on the phase difference between the reflected light by the distance measuring light (laser beam) irradiated toward the target and the reference light irradiated on the internal reference optical path. A phase difference type optical distance meter is known. When distance measurement is performed using this type of lightwave distance meter, non-prism measurement using a low-reflectance wall as a target and prism measurement using a reflective prism as a target are performed.

  When performing non-prism measurement (visible light), the reflectivity of the target is much smaller than that of the reflective prism, so the power of the distance measuring light (laser beam) to be irradiated on the target is very large or small. It is necessary to make the beam diameter of the distance measuring light as small as possible with power and increase the energy density per unit area in the target. However, the intensity of the distance measuring light to be irradiated is limited due to safety. In this case, in the non-prism measurement, considering the necessity of specifying the measurement point and the measurement efficiency, it is desirable to make the beam diameter of the distance measuring light as small as possible. In general, the reflectivity of the target is very low compared to the prism, and therefore the measurement distance is shorter in the non-prism measurement than in the prism measurement.

  On the other hand, prism measurement (invisible light) has a higher target reflectivity than non-prism measurement, so it can be measured over long distances. However, when collimating a target such as a reflective prism, Irradiation makes it easier to catch the target, so it is desirable to use distance measuring light (laser beam) having a relatively large beam spread.

  Thus, while the non-prism measurement (visible light) requires a relatively small beam diameter of the distance measuring light, the prism measurement (non-visible light) requires a relatively large beam diameter of the distance measuring light. Since it is necessary, it is not preferable to use a light wave distance meter configured for non-prism measurement as it is for prism measurement. On the other hand, it is uneconomical if the non-prism measuring light wave distance meter and the prism measuring light wave distance meter are configured separately.

  In view of this, there has been proposed a non-prism measurement and prism measurement that can be performed with a single optical distance meter (see Patent Document 1).

Japanese Patent Laid-Open No. 2004-212059

  In the prior art, when performing non-prism measurement and prism measurement using a single light source, a non-prism measurement optical path and a prism measurement optical path are provided separately, and the optical path is switched during non-prism measurement and prism measurement. Since the optical path is switched using the means, the optical path may be distorted due to errors in the mechanically movable parts constituting the optical path switching means, or a failure may occur due to an abnormality of the movable parts. It is feared to do.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to use a means for distributing light having different wavelengths into ranging light and reference light as a mechanical movable part. It is to perform prism measurement and prism measurement.

  In order to achieve the above object, in the optical distance meter according to claim 1, a light emitting means for emitting a plurality of lights having different wavelengths as light whose intensity is modulated by a modulation signal, and one light from the light emitting means. Introducing and distributing the first distance measuring light or first reference light to the second distance measuring light or second reference light by introducing the other light from the light emitting means and the light distribution means; A first distance measuring light transmitting means for introducing the first distance measuring light from the light distributing means and transmitting it to the measuring optical path; a second distance measuring light from the light distributing means for introducing and diverging; Second distance measuring light transmitting means for transmitting the second distance measuring light to the measurement optical path, and introducing the first reference light or the second reference light from the light distributing means to the reference optical path. A reference light transmitting means that emits light, and reflected with the transmission of the first distance measuring light or the second distance measuring light. When the reflected light is received, photoelectric conversion is performed to generate a ranging signal, and when the first reference light or the second reference light is received from the reference optical path, photoelectric conversion is performed to generate a reference signal. Calculating the distance to the target by comparing the photoelectric conversion means, the ranging signal obtained based on the first ranging light, and the reference signal obtained based on the first reference light A calculation means for calculating a distance to the target by comparing a distance measurement signal obtained on the basis of the second distance measurement light and a reference signal obtained on the basis of the second reference light; Configured.

  (Function) When non-prism measurement is performed when light having different wavelengths is emitted by the light emitting means as light whose intensity is modulated by a modulation signal, the first ranging light is introduced by introducing one light from the light emitting means. Alternatively, the light is distributed to the first reference light, the first ranging light is transmitted to the measurement optical path, the first reference light is transmitted to the reference optical path, and the measurement object is transmitted along with the transmission of the first ranging light. The reflected light reflected by the (target), for example, the reflected light reflected by a low-reflectance wall or the like is photoelectrically converted to generate a ranging signal, and the first reference light from the reference optical path is photoelectrically converted and referenced. A non-prism measurement can be performed by generating a signal and comparing the generated distance measurement signal with a reference signal to obtain a distance to the target. On the other hand, when performing prism measurement, the other light is introduced from the light emitting means and distributed to the second distance measuring light or the second reference light, the second distance measuring light is introduced to diverge, and the diverged second light is emitted. The distance measurement light is transmitted to the measurement optical path, the second reference light is transmitted to the reference optical path, and the reflected light reflected by the measurement object (target) along with the transmission of the second distance measurement light, for example, The reflected light reflected by the reflecting prism is photoelectrically converted to generate a ranging signal, the second reference light from the reference optical path is photoelectrically converted to generate a reference signal, and the generated ranging signal and reference signal are By comparing and calculating the distance to the target, prism measurement can be performed. That is, the light distribution means that distributes the light having different wavelengths to the distance measurement light and the reference light, for example, the optical path switching shutter is excluded, and the distance measurement light is transmitted using a movable part constituted by other mechanical elements. Therefore, it is possible to perform non-prism measurement and prism measurement without switching the optical path, thereby contributing to improvement in reliability.

  According to a second aspect of the present invention, in the optical distance meter according to the first aspect, the light-emitting means includes a first light-emitting element that emits the one light with visible light, and the other the infrared light. A second light emitting element that emits light is provided.

  (Operation) For example, a visible light laser diode is used as the first light emitting element that generates visible light, and the beam diameter of the distance measuring light (laser beam) can be reduced as much as possible. Non-prism measurement can be performed efficiently with the power of light. On the other hand, by using an infrared laser diode, for example, as the second light emitting element that emits the other light with infrared light, divergent distance measuring light can be obtained, and the target (reflecting prism) can be obtained in prism measurement. ) Can be performed roughly to some extent, and the measurement work becomes easy.

  As is clear from the above description, the light wave distance meter according to claim 1 can contribute to the improvement of reliability.

  According to the second aspect, the non-prism measurement can be efficiently performed with less light power, and the measurement work in the prism measurement can be easily performed.

  Hereinafter, embodiments of the present invention will be described based on examples. FIG. 1 is a block configuration diagram of a light wave distance meter according to an embodiment of the present invention during non-prism measurement, and FIG. 2 is a block configuration diagram of a light wave distance meter during prism measurement according to an embodiment of the present invention. FIG. 3 is a main part configuration diagram showing another embodiment of the light source.

  In these drawings, a phase difference type optical wave distance meter 10 includes a two-wavelength laser diode 12, a collimating lens 14, an optical path switching shutter 16, a collimating lens 18, an optical fiber 20, a dichroic mirror 22, a collimating lens 24, and infrared light. Optical fiber 26, collimating lens 28, dichroic mirror 30, reflecting mirrors 32 and 34, objective lens 36, dichroic prism 38, light quantity adjusting diaphragm 40, light receiving diode 42, amplification / frequency converter 44, control unit 46, visible light laser A diode drive circuit 48 and an infrared laser diode drive circuit 50 are provided, and the collimating optical system includes an objective lens 36, a focusing lens 67, a dichroic prism 38, a focusing screen 68, and an eyepiece lens 69. Therefore, the target or collimation point can be confirmed by this collimation optical system. A crosshair is provided on the focusing screen 68, and the intersection of the crosshairs is the collimation axis of the collimation optical system.

  The two-wavelength light emitting laser diode 12 includes, as light sources, a visible light laser diode 12a as a first light emitting element that emits visible light and an infrared light laser diode 12b as a second light emitting element that emits infrared light. The visible light laser diode 12a is connected to the control unit 46 via the visible light laser diode drive circuit 48, and the infrared light laser diode 12b is provided with the infrared light laser diode drive circuit 50. To the control unit 46.

  The control unit 46 has a function as a signal generator that outputs the modulation signal 100 to each of the driving circuits 48 and 50 and outputs a selection signal 102 for driving the driving circuit 48 to the driving circuit 48. At the same time, it has a function as a signal processor that outputs a selection signal 104 for driving the drive circuit 50 to the drive circuit 50. As the modulation signal 100, for example, a signal with a frequency of 75 MHz, 250 kHz, or the like is used. When the modulation signal 100 is output to the drive circuits 48 and 50, when the selection signal 102 is output from the control unit 46 and the visible light LD drive circuit 48 is driven, the visible light laser diode 12a The light whose intensity is modulated by the modulation signal 100, for example, a laser beam having a wavelength of 655 nm, is emitted. On the other hand, when the modulation signal 100 is output, when the selection signal 104 is output from the control unit 46 and the drive circuit 50 for the infrared light LD is driven, the modulation signal is output from the infrared laser diode 12b. Light whose intensity is modulated by 100, for example, a laser beam having a wavelength of 780 nm, is emitted. That is, the visible light laser diode 12a, the infrared light laser diode 12b, the drive circuits 48 and 50, and the control unit 46 are configured as light emitting means for emitting light having different wavelengths as light whose intensity is modulated by the modulation signal. . Two-wavelength laser diodes are commercially available (for example, Sony: SLD6164, Sharp: GH30507T2A, Rohm: RLD2WMUV2, etc.).

  The light emitted by the visible light laser diode 12a or the infrared light laser diode 12b is introduced into the collimator lens 14 and enters the optical path switching shutter 16 as a substantially parallel light beam. The optical path switching shutter 16 includes a plane parallel glass 52, and the plane parallel glass 52 is disposed on the optical axis 54 of the collimator lens 14 with an inclination of 45 °. The plane parallel glass 52 reflects a part of the light (laser beam) that has passed through the collimating lens 14 toward the collimating lens 18 and allows the other light to pass through the optical axis 54 as it is. The optical path switching shutter 16 is rotatably arranged with the central portion of the parallel flat glass 52 as a rotation center so as to shield the light reflected by the parallel flat glass 52.

  Specifically, by utilizing the property of the parallel plane glass 52, the optical path switching shutter 16 allows the light connecting the collimating lens 14 and the dichroic mirror 22 to pass therethrough, and the light connecting the collimating lens 14 and the collimating lens 18 to be transmitted. It is rotated to the first position (vertical position) to be shielded, or the light connecting the collimating lens 14 and the dichroic mirror 22 is shielded, and the light connecting the collimating lens 14 and the collimating lens 18 is passed through. It rotates to a position (90 ° position).

  In this case, when the visible light laser diode 12a emits light and the optical path switching shutter 16 is in the first position (vertical position), the light emitted from the visible light laser diode 12a is converted into the first distance measuring light. As shown, the light is distributed to the dichroic mirror 22 side, and when it is at the second position (90 ° position), the light emitted from the visible light laser diode 12a is distributed to the collimator lens 18 side as the first reference light. Further, when the infrared laser diode 12b emits light and the optical path switching shutter 16 is in the first position (vertical position), the light from the infrared laser diode 12b emits light for the second distance measurement. When the light is distributed to the dichroic mirror 22 side and is at the second position (90 ° position), the light emitted from the infrared laser diode 12b is distributed to the collimator lens 18 side as the second reference light.

  That is, the optical path switching shutter 16 and the parallel flat glass 52 introduce light from the visible light laser diode 12a through the collimator lens 14, and introduce the introduced light (visible light) to the first distance measuring light and the first distance measuring light. The light is distributed to the reference light, and the light emitted from the infrared laser diode 12a is introduced through the collimator lens 14, and the introduced light (infrared light) is converted into the second distance measuring light and the second reference light. It is configured as a light distribution means for distributing.

  The first distance measuring light or the second distance measuring light that has passed through the optical path switching shutter 16 enters the dichroic mirror 22. The dichroic mirror 22 allows only the first ranging light (ranging light generated by the visible light laser diode 12a) out of the first ranging light or the second ranging light that has passed through the optical path switching shutter 16 to pass therethrough. The second ranging light (ranging light by the light emitted from the infrared laser diode 12a) is reflected to the collimating lens 24 side. The first distance measuring light that has passed through the dichroic mirror 22 passes through the dichroic mirror 30 configured in the same manner as the dichroic mirror 22, and then is transmitted toward the measurement optical path 56 through the reflecting mirrors 32 and 34. The dichroic mirrors 22 and 30 have a function of reflecting infrared light and allowing visible light to pass therethrough. The reflecting mirror 34 may be configured on the rear side of the objective lens 36.

  That is, the dichroic mirrors 22 and 30 and the reflecting mirrors 32 and 34 are configured as first distance measuring light transmitting means for transmitting the first distance measuring light distributed by the optical path switching shutter 16 to the measuring optical path 56. As shown in FIG. 1, the first distance measuring light according to the light emitted from the visible light laser diode 12a is emitted as a target such as a wall 57 having a low reflectance existing on the measurement light path 56. ing. In this case, it is used for non-prism measurement.

  On the other hand, the second ranging light (ranging light by the light emitted from the infrared laser diode 12b) that has passed through the optical path switching shutter 16 is reflected by the dichroic mirror 22, condensed by the lens 24, and infrared optical fiber. 26 is diffused in the process of passing through the optical fiber 26, and is emitted through the collimating lens 28 as light having a light emission area of several μm at the time of a laser diode to a light emission area of several hundred μmφ which is the diameter of the optical fiber. The light is emitted toward the dichroic mirror 30, reflected by the dichroic mirror 30, and then transmitted to the measurement optical path 56 through the reflecting mirrors 32 and 34.

  That is, the dichroic mirror 22, the collimating lens 24, the infrared optical fiber 26, the collimating lens 28, the dichroic mirror 30, and the reflecting mirrors 32 and 34 use the second distance measuring light distributed by the optical path switching shutter 16 as the measurement optical path. 2, the second distance measuring light that is transmitted by the infrared laser diode 12 b is present on the measurement optical path 56 as shown in FIG. 2. The reflecting prism 58 is emitted toward the reflecting prism 58 as a target. In this case, it is used for prism measurement.

  The optical fiber for infrared light 26 divides the distance measuring light (second distance measuring light) incident from the collimating lens 24, and the distance measuring light is emitted when the diverging distance measuring light is emitted toward the collimating lens 28. Light is emitted as a divergent beam.

Specifically, when the size of the light emitting surface of the infrared laser diode 12b is about 3 μm ² (≈3 × 1 μm) and the focal length of the collimating lens 14 is 10 mm, the distance measuring light that has passed through the collimating lens 14 The divergence angle is 0 ° 1′2 ″. If a light emitting diode having a light emitting side of about 200 μm is used instead of the infrared laser diode 12b, and the focal length of the collimating lens 14 is 100 mm, the collimating lens 14 is The divergence angle of the distance measuring light that has passed becomes 0 ° 6′53 ″.

  On the other hand, if a 60 μm optical fiber 26 for infrared light is used and the focal length of the collimating lens 24 is 30 mm, the divergence angle of the distance measuring light that has passed through the optical fiber 26 is 0 ° 5′44 ″. That is, by passing the distance measuring light through the optical fiber 26, almost the same divergence angle as when a light emitting diode is used as the light source can be obtained.

  Ranging light accompanying light emission of the visible light laser diode 12a or the infrared light laser diode 12b is transmitted toward the measuring optical path 56, and the ranging light is transmitted to the wall 57 or the reflecting prism 58, etc. existing on the measuring optical path 56. When reflected by the target, the reflected light passes through the reflecting mirror 34 and then enters the dichroic prism 38 via the objective lens 36, and after being reflected by the dichroic prism 38, passes through the light amount adjusting diaphragm 40 and enters the light receiving diode 42. It is supposed to be. As described above, the collimating optical system is configured so that the dichroic prism 38 is provided with a filter film so as to guide part of visible light and infrared light to the light receiving diode 42. It is something to burn. Generally, it is used by being incorporated into a total station, which is a distance measuring / angle measuring instrument.

  The light amount adjusting diaphragm 40 is constituted by, for example, a motor 40a, a rotating plate 40b, and a rotating shaft 40c of the motor 40a. On the rotating plate 40b, for example, a plurality of filters having different light transmittances are arranged along the circumferential direction, and any of the filters is connected to the dichroic prism 38, the light receiving diode 42, and the like with the rotation of the motor 40a. Is inserted into the optical path connecting the two. That is, the amount of reflected light incident on the light receiving diode 42 is always constant by inserting one of the filters of the rotating plate 40b in accordance with the measurement distance in the optical path connecting the dichroic prism 38 and the light receiving diode 42. In this way, the light amount can be adjusted. A known filter can be used as the filter of the rotating plate 40.

  In addition to the reflected light from the target, the reference light from the optical fiber 20 is incident on the light receiving diode 42, and the reference light is incident on the optical fiber 20 from the collimating lens 18. Yes. Specifically, the first reference light or the second reference light distributed by the optical path switching shutter 16 is incident on the collimating lens 18 disposed in the vicinity of the optical fiber 20 constituting the internal reference optical path. It has become. In other words, the collimating lens 18 has the first reference light (reference light emitted from the visible light laser diode 12a) or the second reference light (reference light emitted from the infrared laser diode 12b) distributed by the optical path switching shutter 16. ) To the optical fiber 20 as an internal reference optical path.

  When the light receiving diode 42 receives the reflected light that has passed through the dichroic prism 38, the light receiving diode 42 performs photoelectric conversion on the reflected light to generate a ranging signal, while the first reference light or second light that has passed through the optical fiber 20 is generated. Are configured as photoelectric conversion means for generating a reference signal by performing photoelectric conversion on each reference light when the reference light is received, and the ranging signal or the reference signal output from the light receiving diode 42 is amplified and frequency converted, respectively. Is output to the device 44.

  The amplifier / frequency converter 44 includes an amplifier that amplifies the distance measurement signal or the reference signal, and converts the distance measurement signal or the reference signal into an intermediate frequency distance measurement signal or a reference signal having a frequency lower than those signals. A mixer (mixer) for conversion and a local oscillator are provided, and a ranging signal or reference signal based on an intermediate frequency is supplied to the control unit 46, respectively.

  The control unit 46 includes, for example, a microcomputer having a CPU, RAM, ROM, etc., a signal generator, and the like, and is configured to perform various calculations by inputting a distance measurement signal or a reference signal using an intermediate frequency. . For example, the control unit 46 obtains the phase difference between the distance measurement signal generated based on the light emission of the visible light laser diode 12a and the reference signal, and the wall 57 etc. existing on the measurement optical path 56 based on this phase difference. It has a function as a calculation means for calculating the distance to the target, obtains a phase difference between the distance measurement signal generated based on the light emission of the infrared laser diode 12b and the reference signal, and uses this phase difference And a function as a calculation means for calculating a distance to a target such as a reflecting prism 58 existing on the measurement optical path 56.

  When performing non-prism measurement using the optical wave distance meter 10 having the above-described configuration, as shown in FIG. 1, when an operator performs an operation for causing the visible light laser diode 12a to emit light, the control unit 46 performs control. The selection signal 102 is output from the unit 46 to the drive circuit 48, and the visible light laser diode 12a emits light. At this time, when the optical path switching shutter 16 rotates to the first position (vertical position) that allows the light connecting the collimating lens 14 and the dichroic mirror 22 to pass and shields the light connecting the collimating lens 14 and the collimating lens 18, The light emitted from the visible light laser diode 12a passes through the collimating lens 14, the parallel plane glass 52, and the optical path switching shutter 16, and then is used as distance measuring light (first distance measuring light) as dichroic mirrors 22 and 30 and a reflecting mirror. The light is emitted toward a target such as a wall 57 existing on the measurement optical path 56 via 32 and 34. At this time, the reflected light reflected by the target enters the light receiving diode 42 after passing through the reflecting mirror 34, the objective lens 36, the dichroic prism 38, and the light quantity forced aperture 40.

  Next, the optical path switching shutter 16 is switched to block the light connecting the collimating lens 14 and the dichroic mirror 22 and to pass the light connecting the collimating lens 14 and the collimating lens 18 (90 ° position). , The light emitted from the visible light diode 12a is introduced as reference light (first reference light) to the collimating lens 18 through the collimating lens 14, the parallel flat glass 52, and the optical path switching shutter 16, and then introduced. The reference light enters the light receiving diode 42 via the optical fiber 20.

  The reflected light incident on the light receiving diode 42 is converted into a distance measurement signal, amplified by the amplification / frequency converter 44 and then input to the control unit 46 as an intermediate frequency distance measurement signal. On the other hand, the reference light incident on the light receiving diode 42 is converted into a reference signal, amplified by the amplification / frequency converter 44 and then input to the control unit 46 as an intermediate frequency reference signal. In the control unit 46, the phase difference between the input ranging signal and the reference signal is obtained, and the distance to the target such as the wall 57 is obtained based on this phase difference. In this case, the distance measuring light (first distance measuring light) is emitted to the target with a beam diameter as small as possible, so that the distance to the target can be obtained efficiently.

  Next, when performing prism measurement, as shown in FIG. 2, when an operator performs an operation for causing the infrared laser diode 12 b to emit light to the control unit 46, the control unit 46 changes the drive circuit 50. A selection signal 104 is output, and the infrared laser diode 12b emits light. At this time, when the optical path switching shutter 16 rotates to the first position (vertical position) that allows the light connecting the collimating lens 14 and the dichroic mirror 22 to pass and shields the light connecting the collimating lens 14 and the collimating lens 18, The light emitted from the infrared laser diode 12b passes through the collimating lens 14, the parallel flat glass 52, and the optical path switching shutter 16, and then is reflected by the dichroic mirror 22 as distance measuring light (second distance measuring light). After passing through the lens 24, it is introduced into the optical fiber 26 for infrared light, diverges by this optical fiber 26, and then enters the collimating lens 28. The diverging distance measuring light passes through the collimating lens 28, is reflected by the dichroic mirror 30, and is emitted toward the target such as the reflecting prism 58 existing on the measuring light path 56 via the reflecting mirrors 32 and 34. The reflected light reflected by the reflecting prism 58 enters the light receiving diode 42 after passing through the reflecting mirror 34, the objective lens 36, the dichroic prism 38, and the light quantity forced aperture 40.

  Next, the optical path switching shutter 16 is switched at a constant timing to shield the light connecting the collimating lens 14 and the dichroic mirror 22 and to pass the light connecting the collimating lens 14 and the collimating lens 18 ( 90 ° position), the light emitted from the infrared laser diode 12b passes through the collimating lens 14 and the parallel flat glass 52 and is then introduced into the collimating lens 18 as reference light (second reference light). The reference light that has passed through the optical fiber 20 enters the light receiving diode 42.

  The reflected light incident on the light receiving diode 42 is converted into a distance measurement signal, then amplified by the amplification / frequency converter 44, converted into an intermediate frequency distance measurement signal, and input to the control unit 46. On the other hand, the reference light incident on the light receiving diode 42 is converted into a reference signal, then amplified by the amplification / frequency converter 44, converted into an intermediate frequency reference signal, and input to the control unit 46. In the control unit 46, the phase difference between the inputted distance measurement signal and the reference light is obtained, and the distance to the target such as the reflecting prism 58 existing on the measurement light path 56 is calculated based on this phase difference. Is done. At this time, the distance measuring light according to the light emission of the infrared laser diode 12b is diverged by the optical fiber 26 for infrared light and is emitted toward the reflecting prism 58 as a divergent light transmission beam. Even if 58 is collimated roughly to some extent, prism measurement can be accurately performed, and measurement work can be easily performed.

  As described above, in this embodiment, since the optical path of the distance measuring light is not switched by using the movable part constituted by mechanical elements other than the optical path switching shutter 16, the optical path is distorted by the movable part. Or a failure due to an abnormality of the movable part can be prevented, which can contribute to improvement of reliability.

  Further, according to the present embodiment, by using the visible light laser diode 12a, the beam diameter of the distance measuring light (laser beam) can be made as small as possible, non-prism measurement can be performed efficiently, and red By using the external light laser diode 12b, divergent distance measuring light can be obtained, the target 58 can be collimated to some extent roughly in the prism measurement, and the measurement work is facilitated.

  In this embodiment, the visible light laser diode 12a and the infrared light laser diode 12b are integrated as the two-wavelength light emitting laser diode 12. However, as shown in FIG. The external light laser diodes 12b are individually disposed, the collimating lens 14a and the dichroic mirror 60 are disposed between the visible light laser diode 12a and the optical path switching shutter 16, and the optical path switching shutter 16 and the infrared laser diode 12b. A configuration in which the collimating lens 14b and the dichroic mirror 60 are disposed between them may be employed.

It is a block block diagram at the time of the non-prism measurement of the light wave distance meter which shows one Example of this invention. It is a block block diagram at the time of the prism measurement of the light wave distance meter which shows one Example of this invention. It is a principal part block diagram which shows the other Example of a light source.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light wave rangefinder 12 Two-wavelength light emitting laser diode 12a Visible light laser diode 12b Infrared laser diode 14 Collimating lens 16 Optical path switching shutter 18 Collimating lens 20 Optical fiber 22 Dichroic mirror 24 Lens 26 Optical fiber 28 for infrared light 28 Collimating lens 30 Dichroic mirror 32, 34 Reflective mirror 36 Objective lens 38 Dichroic prism 40 Light quantity adjusting diaphragm 42 Light receiving diode 44 Amplifying / frequency converter 46 Control unit 48, 50 Drive circuit 58 Reflective prism

Claims (2)

  A light emitting means for emitting a plurality of lights having different wavelengths as light whose intensity is modulated by a modulation signal, and introducing one light from the light emitting means and distributing it to the first distance measuring light or the first reference light; A light distribution unit that introduces the other light from the light emitting unit and distributes it to the second distance measuring light or the second reference light, and a first distance measuring light that is introduced from the light distribution unit and transmitted to the measurement optical path. A second distance measuring light transmitting means and a second distance measuring light that is diverged by introducing the second distance measuring light from the light distributing means, and transmits the diverged second distance measuring light to the measurement optical path. A distance light transmitting means, a reference light transmitting means for introducing the first reference light or the second reference light from the light distributing means and transmitting the light to a reference optical path, and the first distance measuring light or the first distance measuring light. When the reflected light reflected by the measurement optical path is received along with the transmission of the distance measurement light of 2, the distance measurement signal is obtained by performing photoelectric conversion. Based on the first distance measuring light and the photoelectric conversion means for generating a reference signal by performing photoelectric conversion when receiving the first reference light or the second reference light from the reference light path Comparing the obtained ranging signal with the reference signal obtained based on the first reference light to calculate the distance to the target, and the ranging obtained based on the second ranging light A light wave distance meter comprising: a calculation means for calculating a distance to the target by comparing a signal and a reference signal obtained based on the second reference light.   2. The light wave distance meter according to claim 1, wherein the light emitting means includes a first light emitting element that emits the one light with visible light, and a second light emitting element that emits the other light with infrared light. A light wave distance meter characterized by comprising.

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