WO2014129210A1

WO2014129210A1 - Distance measuring device and calibration method

Info

Publication number: WO2014129210A1
Application number: PCT/JP2014/000993
Authority: WO
Inventors: 仁大室; 孝雄滝澤; 陽介宮▲崎▼
Original assignee: 株式会社ニコンビジョン
Priority date: 2013-02-25
Filing date: 2014-02-25
Publication date: 2014-08-28
Also published as: DE112014000971T5

Abstract

A distance measuring device comprises a light transmitting unit that transmits a signal light from a light source toward an object, a light receiving unit that has a light receiving component and receives the signal light from the object on a different light axis than the light transmitting unit, a distance measuring unit that measures the distance to the object on the basis of the propagation time, from transmission to reception, of the signal light, and a correcting unit that corrects, when one of either the light path from the light transmitting unit to the light receiving unit and the light path from the object to the light receiving component is fixed, the light path of the signal light by displacing the light path of the other of the light transmitting unit or the light receiving unit.

Description

Ranging device and calibration method

The present invention relates to a distance measuring device and a calibration method.

There is a distance measuring device that measures the distance to an object based on the propagation time of signal light reflected by the object (see, for example, Patent Document 1).
[Patent Document 1] International Publication No. 2009/31550

Sighting the target object with the distance measuring device may be difficult due to image blur.

In the first aspect of the present invention, a light transmission unit that transmits signal light from a light source toward an object and a light receiving element, and the signal light from the object is on an optical axis different from that of the light transmission unit. A light receiving unit for receiving light, a distance measuring unit for measuring a distance to an object based on a propagation time of signal light from light transmission to light reception, an optical path to the light transmission unit and the light receiving unit, and a light receiving element from the object A distance measuring device is provided that includes a correction unit that corrects the optical path of the signal light by displacing the optical path in the other of the light transmitting unit and the light receiving unit in a state in which one of the optical paths up to is fixed.

In the second aspect of the present invention, a light transmitting unit that transmits the signal light from the light source toward the object and a light receiving element, the signal light from the object is on an optical axis different from that of the light transmitting unit. In a state where the optical axis of the light receiving unit, the distance measuring unit for measuring the distance to the object based on the propagation time from the transmission of the signal light to the reception of light, and the one optical axis of the light transmission unit and the light receiving unit are fixed, A calibration method for calibrating a distance measuring device including a correction unit that corrects an optical path of signal light by displacing an optical path at the other of a light transmission unit and a light reception unit, and reflects the light to a known standard object while displacing the optical path There is provided a calibration method comprising the steps of measuring the received light intensity of the received signal light at the light receiving portion and determining the initial position of the optical path by displacing the optical path.

The above summary of the invention does not enumerate all the necessary features of the present invention. Sub-combinations of these feature groups can also be an invention.

1 is a schematic cross-sectional view of a distance measuring device 10. FIG. 3 is a schematic diagram for optically explaining a distance measuring operation of the distance measuring device 10. FIG. 4 is a flowchart showing a procedure of a distance measuring operation of the distance measuring device 10. FIG. 10 is a schematic diagram illustrating a correction operation of the correction unit 300. FIG. 10 is a schematic diagram illustrating a correction operation of the correction unit 300. 4 is a diagram showing a spot image formed on a light receiving element 430. FIG. It is a schematic diagram explaining the displacement conditions of signal light. FIG. 10 is a schematic diagram illustrating a correction operation of the correction unit 300. 5 is a flowchart for explaining the operation of the correction unit 300. 5 is a diagram illustrating an example of a control method of a correction unit 300. FIG. 6 is a schematic diagram illustrating another correction operation of the correction unit 300. FIG. 3 is a schematic diagram illustrating parallax correction in the distance measuring device 10. FIG. It is a schematic diagram explaining parallax correction when a correction unit is arranged in the light transmission unit. 3 is a schematic diagram illustrating parallax correction in the distance measuring device 10. FIG. It is a schematic diagram explaining parallax correction when a correction unit is arranged in the light receiving unit. 2 is a schematic cross-sectional view of a distance measuring device 11. FIG. It is a schematic diagram explaining the correction | amendment operation | movement of the correction | amendment part 301. FIG. 3 is a schematic cross-sectional view of a distance measuring device 12. FIG. It is a schematic diagram explaining the correction | amendment operation | movement of the correction | amendment part 302. FIG. 3 is a schematic cross-sectional view of a distance measuring device 13. FIG. 4 is a diagram showing a spot image formed on a light receiving element 430. FIG. It is a schematic diagram explaining the effect | action of the correction member. It is a schematic diagram which shows the state of the distance measuring device 13 which performs a calibration operation. 6 is a schematic diagram illustrating scanning of signal light by a calibration unit 600. FIG. It is a graph which shows the received light intensity of the signal light which the light receiving element 430 detects. It is a flowchart which shows the procedure of the calibration operation | movement of the calibration part 600. FIG. 6 is a schematic diagram illustrating scanning of signal light by a calibration unit 600. FIG. 5 is a graph showing the intensity of received light of the light receiving element 430. 6 is a schematic diagram of an auxiliary member 700. FIG. 2 is a schematic diagram of a reticle plate 120. FIG.

Subsequently, the present invention will be described through embodiments of the invention. The following embodiments do not limit the invention according to the claims. Not all combinations of features described in the embodiments are essential for the solution of the invention.

FIG. 1 is a schematic cross-sectional view of the distance measuring device 10. The distance measuring device 10 includes a collimating unit 100, a light transmitting unit 200, a correcting unit 300, a light receiving unit 400, and a distance measuring unit 500. In the following description, the side on which the collimation unit 100 is arranged in the distance measuring device 10 is the rear side. In the distance measuring device 10, the side facing the object of distance measurement is the front side.

The collimation unit 100 includes an eyepiece optical system 110, a reticle plate 120, and an erecting prism 130. The collimation unit 100 also serves as the objective optical system 220 and the light transmission unit 200, and the correction member 310 serves as the correction unit 300.

The rear end of the eyepiece optical system 110 is exposed on the rear end surface of the distance measuring device 10. The front end of the eyepiece optical system 110 faces the rear end of the erecting prism 130 inside the distance measuring device 10. The user of the distance measuring device 10 collimates the distance measuring device 10 by visually recognizing the image of the object through the eyepiece optical system 110.

The reticle plate 120 has a reticle formed by printing, etching or the like on a plate transparent to visible light. The reticle has collimation indicators such as a crosshair, a rectangular frame, and a circular frame. The user of the distance measuring device 10 collimates the distance measuring device 10 on the object by superimposing a reticle collimation index on an image observed through the eyepiece optical system 110. As the reticle, a display image of a transmissive liquid crystal display panel can be used.

The erecting prism 130 includes a dichroic reflecting surface 132 that reflects the visible light band and transmits the infrared band, and total reflection surfaces 134 and 136 that have a high reflectance in the infrared band in addition to the visible light band. Have. The erecting prism 130 also has another reflecting surface that is not assigned a reference number, and reverses the inverted mirror image formed by the incident light beam to an erecting erect image. The erecting prism 130 can be formed using a roof prism, a porro prism, or the like.

The light transmitting unit 200 includes a light emitting unit 210 and an objective optical system 220. Further, the light transmitting unit 200 also serves as a collimating unit 100 using a part of the erecting prism 130 including the dichroic reflecting surface 132 and the total reflecting surface 134. Further, the light transmission unit 200 also uses the correction member 310 as the correction unit 300.

The light emitting unit 210 includes a light emitting element such as a semiconductor laser as a light source, and emits pulsed signal light when the distance measuring device 10 performs a distance measuring operation. In the present embodiment, the signal light is, for example, infrared light. The objective optical system 220 is disposed at the front end of the distance measuring device 10, and the front end surface faces the object to be distance-measured. The rear end face of the objective optical system 220 faces the front end face of the erecting prism 130 with the correction member 310 interposed therebetween. The correction member 310 is also an optical member, and forms a light transmission optical system together with the objective optical system 220.

Note that the wavelength of the signal light may be other than the visible band, for example, ultraviolet light. When the signal light is ultraviolet light, the dichroic reflecting surface 132 of the erecting prism 130 reflects the visible light band and transmits the ultraviolet light band. The total reflection surface 134 reflects the visible light band and the ultraviolet band.

The correction unit 300 includes a correction member 310 and a drive unit 320. The correction member 310 includes a lens that forms part of the eyepiece optical system 110 and the objective optical system 220. The drive unit 320 displaces the correction member 310 in a direction that intersects the optical axis of the correction member 310. Further, the drive unit 320 may swing the correction member 310 in the direction in which the main surface swings.

As the correction member 310, a oscillating prism can be used in addition to the displacing lens. In addition, a variable apex angle prism that can change the apex angle formed by the incident surface and the exit surface by swinging a member that forms the entrance surface or the exit surface can also be used as the correction member 310. As the driving unit 320, a voice coil motor, a piezoelectric motor, or the like can be used.

In the distance measuring device 10, among the light reflected or scattered from the object located in front of the distance measuring device 10, a light ray A ₁ propagating within the range of the expected angle of the objective optical system 220 is reflected by the objective optical system 220. Incident through. The light ray A ₁ is transmitted through the correction member 310 and propagates backward as the light ray A ₂ through the distance measuring apparatus 10, and passes through the erecting prism 130, the reticle plate 120, and the eyepiece optical system 110. It is emitted as light a ₃ rearward. Thereby, the user can observe an erect image of the object through the eyepiece optical system 110.

The reticle arranged on the reticle plate 120 is superimposed on the image of the object observed by the user through the eyepiece optical system 110. Therefore, the user can collimate the distance measuring device 10 by displacing the distance measuring device 10 to make the reticle coincide with the object.

Note that an optical member that changes the focal length of the eyepiece optical system 110 may be provided as a part of the eyepiece optical system 110 or in addition to the eyepiece optical system 110. Thereby, it is possible to make the user observe a clear image regardless of the distance to the object. Moreover, diopter correction according to the user's visual acuity can be performed.

For example, the user instructs the distance measuring device 10 to start a distance measuring operation by operating a switch such as a button provided on the distance measuring device 10. When the user instructs the distance measuring device 10 to perform distance measurement, the light emitting unit 210 emits pulsed signal light as a light beam B ₁ toward the upper surface of the erecting prism 130 in the drawing. In the erecting prism 130, the signal light passes through the dichroic reflecting surface 132, is reflected by the total reflecting surface 134, and propagates forward in the distance measuring device 10 as the light beam B ₂ .

Further, the signal light is projected outside through the correction member 310 and the objective optical system 220 toward the front of the distance measuring device 10 as the light beam B ₃ . Signal light projected as rays B ₃ is projected to the object of distance measurement that is collimated by the user. When the distance to the object to be measured is assumed to be several hundred meters, the spread of the projected signal light may be set to about ± 0.05 °, for example.

An optical member that changes the focal length of the objective optical system 220 may be provided as a part of the objective optical system 220 or in addition to the objective optical system 220. As a result, a clearer image can be observed in the collimation unit 100, and an object to be measured can be selected with high accuracy by reducing the beam diameter of the signal light.

The correction member 310 transmits the light beam A ₂ incident on the inside of the distance measuring device 10 and the light beam B ₂ emitted from the distance measuring device 10 in the vicinity of the objective optical system 220. When the optical axis of the correction member 310 is displaced by being driven by the driving unit 320, the optical paths of the light beams A ₂ and B ₂ are displaced, and the propagation directions thereof are changed.

By propagation direction of the light ray A ₂ is displaced, the image for the user to observe through the collimating section 100 is displaced. In other words, when the distance measuring device 10 is displaced, the blurring of the image observed by the user can be stopped by appropriately displacing the correction member 310. Further, the parallax between the optical system of the light transmitting unit 200 and the optical diameter of the light receiving unit 400 is corrected by appropriately displacing the correction member 310 according to the distance from the distance measuring device 10 to the object to be measured. it can.

Furthermore, by the direction of propagation of the light beam B ₂ is displaced when the optical axis of the correcting member 310 is displaced, the direction of propagation of the light beam B ₃ external to the projected signal light is displaced. Therefore, when the distance measuring device 10 is displaced, the signal light irradiation target can be maintained by appropriately displacing the correction member 310.

The light receiving unit 400 includes an objective optical system 410, a band transmission filter 420, and a light receiving element 430 to form a light receiving optical system. The objective optical system 410 of the light receiving unit 400 has an optical axis different from that of the objective optical system 220 of the light transmitting unit 200.

A band transmission filter 420 and a light receiving element 430 are sequentially arranged behind the objective optical system 410. The band transmission filter 420 has a characteristic of transmitting light in a narrow band including signal light and blocking or attenuating light in other bands. The light receiving element 430 includes a photoelectric conversion element such as a photodiode or a phototransistor having sensitivity to a band of signal light. Thereby, the light receiving element 430 detects the incident signal light and generates an electrical signal corresponding to the detected signal light.

The light beam B ₁ reflected or scattered from the object located in front of the distance measuring device 10 enters the objective optical system of the light receiving unit 400. The light beam B ₁ propagates backward as the light beam B ₂ through the distance measuring device 10, passes through the band-pass filter 420, and is received by the light receiving element 430.

Therefore, the light receiving element 430 detects the signal light included in the incident light beams B ₁ and B ₂ with a high S / N ratio and generates an electrical signal. The electric signal generated by the light receiving element 430 is input to the distance measuring unit 500.

In addition, it is preferable that the light receiving area of the light receiving element 430 is smaller from the viewpoint of eliminating the influence of background light in detecting signal light. An optical member that changes the focal length of the optical system may be provided as a part of the objective optical system 410 or in addition to the objective optical system 410. Thereby, a small spot light can be received by the light receiving element 430 by reducing the beam diameter of the received signal light.

In the distance measuring apparatus 10, the distance measuring unit 500 includes a clock unit 510, a distance measuring control unit 520, and a display unit 530. The clock unit 510 measures the time taken from when the light transmitting unit 200 transmits the signal light to when the signal light reflected by the object is received.

The ranging control unit 520 comprehensively controls the ranging operation in the ranging device 10. The objects to be controlled by the distance measurement control unit 520 include the light emitting unit 210 of the light transmission unit 200 and the like. The distance measurement control unit 520 calculates the distance between the distance measurement device 10 and the object based on the time measured by the clock unit 510. When the distance measuring device 10 has a function of detecting inclination or the like, the horizontal distance to the object, the height difference, or the like may be calculated. Further, the clock unit 510 may correct the calculation result based on environmental changes such as temperature.

The display unit 530 places the display image at the reticle position by a transmissive liquid crystal display panel, an organic LED display panel, or an optical system (not shown) disposed at the focal position (reticle position) of the objective optical system 220 of the light transmission unit 200. A reflection type liquid crystal display panel having a guiding structure is provided, and the calculation result of the distance measurement control unit 520 such as the distance to the object is shown to the user by characters, images, and the like. The display unit 530 may display the remaining battery amount, an error message, a clock, and the like in addition to the distance measurement result. The user can obtain a distance measurement result and other information while observing the object through the eyepiece optical system 110 of the collimation unit 100.

Further, the display unit 530 may display a message for urging the user to hold the distance measuring device 10 when the blur amplitude or frequency detected by the blur detection unit 340 exceeds a predetermined threshold. Good. Thereby, the burden of the correction | amendment part 300 can be eased and the electric power of the ranging device 10 can be saved.

FIG. 2 is a schematic diagram for optically explaining the distance measuring operation of the distance measuring device 10. FIG. 2 shows a case where the object 20 located at a position sufficiently away from the distance measuring device 10 is measured by the distance measuring device 10 in the horizontal state.

In the following drawings, the propagation direction of the signal light emitted from the light transmitting unit 200 toward the object 20 is described as the Y direction. Also, the direction perpendicular to the Y direction on the paper surface, the direction from the bottom to the top on the paper surface is the Z direction, and the direction from the front to the back of the paper surface among the directions orthogonal to the paper surface is the X direction. Describe. The directions opposite to the X direction, the Y direction, and the Z direction are referred to as the (−X) direction, the (−Y) direction, and the (−Z) direction.

A user who uses the distance measuring device 10 first collimates the object 20. Among the light reflected or scattered from the object 20, the light ray A ₁ propagating in the (−Y) direction within the range of the expected angle of the objective optical system is a distance measuring device through the objective optical system 220 and the correction member 310. 10 is incident. The incident light ray A ₁ propagates in the distance measuring device 10 as a light ray A ₂ , and passes through the erecting prism 130, reticle plate 120, and eyepiece optical system 110 from the rear end of the distance measuring device 10 in the (−Y) direction in the figure. Is injected into.

A user using the distance measuring device 10 collimates the object 20 by aligning the reticle with the image of the object 20 observed through the eyepiece optical system 110. Thereby, the signal light projected as the light beam B ₃ propagating in the Y direction from the light transmitting unit 200 to the front of the distance measuring device 10 is in a state of being irradiated onto the object 20. If the signal light is projected onto the object 20, the signal light reflected on the object 20 as ray C _1, (- Y) propagating in a direction.

In the distance measuring device 10, a part of the light beam C ₁ propagating within the expected angle of the light receiving unit 400 enters the distance measuring device 10 from the objective optical system 410. When the distance from the distance measuring device 10 to the object 20 is assumed to be several hundred meters, the prospective angle of the objective optical system 410 can be set to about ± 0.35 °, for example.

Of the light beam C ₂ propagated in the (−Y) direction through the distance measuring device 10, the band including the signal light is transmitted through the band transmission filter 420 and is incident on the light receiving element 430. The light beam A ₂ is detected by forming a spot image at the approximate center of the light receiving surface of the light receiving element 430. Thus, the distance measuring unit 500 of the distance measuring device 10 was calculated based on the propagation time of the signal light, to display the distance D _L from the distance measuring device 10 to the object 20 towards the user.

FIG. 3 is a flowchart showing an example of the procedure of the distance measuring operation in the distance measuring device 10. When ranging starts in response to an instruction for ranging by a user operation such as turning on a switch, the ranging control unit 520 first instructs the light emitting unit 210 to emit light (step S101). Thereby, the signal light is projected onto the object through the light transmitting unit 200.

The light transmitting unit 200 may repeatedly project pulsed signal light with a period longer than the propagation time until the light receiving unit 400 receives the reflected light. Thereby, even if the reflected light from the object cannot be received for some reason, it can be retried immediately.

Next, the distance measurement control unit 520 determines whether or not the light receiving unit 400 has received the signal light (step S102). When the light receiving unit 400 has received the signal light (step S102: YES), the time taken from the light emitting unit 210 emitting the signal light to the clock unit 510 until the light receiving element 430 detects the signal light. Is measured (step S103), and then the propagation distance of the signal light is calculated (step S104).

Further, the distance measurement control unit 520 displays the distance calculated by the clock unit 510 on the display unit 530 (step S105). In step S104, the clock unit 510 may detect the inclination of the distance measuring device 10 and convert a calculation result based on the measurement into a horizontal distance, a height difference, or the like.

On the other hand, when the light receiving unit 400 cannot receive the signal light in step S102 (step S102: NO), the distance measurement control unit 520 increments the number of times of instructing the light emitting unit 210 to emit light (step S106). Then, it is determined whether or not the number of times has reached a predetermined number (step S107).

If it is determined that the number of distance measurement trials has reached the predetermined number (step S107: YES), the distance measurement control unit 520 stops the distance measurement operation and the display unit 530 indicates that the distance measurement cannot be performed. Display. On the other hand, when it is determined that the number of distance measurement trials has not reached the predetermined number (step S107: NO), the distance measurement control unit 520 repeats the series of distance measurement operations from step S101 again. Thus, the distance measuring device 10 can complete the distance measuring operation with high probability.

Referring again to FIG. 1, the correction unit 300 includes a shake detection unit 340 and a correction control unit 330 in addition to the correction member 310 and the drive unit 320.

The blur detection unit 340 includes a plurality of angular velocity sensors whose detection directions intersect each other. For example, the plurality of angular velocity sensors are arranged in a direction in which pitching and yawing of the distance measuring device 10 are detected. Each angular velocity sensor outputs a signal corresponding to the direction and amount of displacement when the distance measuring device 10 is displaced.

The correction control unit 330 periodically refers to the output of the blur detection unit 340 to determine the displacement direction and the displacement amount of the correction member 310 that cancels the image blur generated in the collimation unit 100 due to the displacement of the distance measuring device 10. calculate. In addition, the correction control unit 330 transmits the calculated displacement direction and displacement amount to the drive unit 320 to drive the correction member 310.

The driving unit 320 displaces the correction member 310 in a direction intersecting the optical axis based on a command received from the correction control unit 330. Thereby, image blurring in the collimation unit 100 is suppressed and signal light is prevented from deviating from the object.

Further, the correction control unit 330 acquires the displacement amount from the correction member 310 and feedback-controls the drive amount of the correction member 310. As a result, the position of the correction member 310 can be accurately controlled even when a disturbance such as impact or vibration is applied.

In addition, although the correction | amendment part 300 may always perform correction | amendment operation | movement, you may perform correction | amendment operation | movement only in the period when the user is using the distance measuring device 10. FIG. The fact that the user is using the distance measuring device 10 may detect, for example, the eyes of the user looking through the eyepiece optical system 110 and turn the correction unit 300 on / off. Further, the correction unit 300 may start the operation when the user operates a switch or the like. Further, the operation of the correction unit 300 may be stopped when there is no user operation beyond a predetermined time.

FIG. 4 is a schematic diagram for optically explaining the correction operation of the correction unit 300 in the distance measuring device 10. The distance measuring device 10 rotates clockwise from the state shown in FIG. 2 to produce an inclination that forms an angle (+ θ ₀ ) with respect to the horizontal plane H. Thereby, the front end of the distance measuring device 10 is displaced in the Z direction, and the optical axis of the objective optical system 220 points upward in the drawing of the object 20.

In the correction unit 300, the blur detection unit 340 detects the rotation of the distance measuring device 10, and the driving unit 320 displaces the correction member 310 in the Z direction. As a result, the light beam A _{1 that} has propagated horizontally in the (−Y) direction from the object 20 toward the distance measuring device 10 is converted into a light beam A ₂ having the same inclination as the inclination of the distance measuring device 10. Propagate inside. Therefore, the image of the object 20 formed on the eyepiece optical system 110 is not displaced.

Further, the optical path of the signal light beam B ₂ tilted together with the distance measuring device 10 inside the distance measuring device 10 is corrected horizontally by the correction member 310. Thereby, the light beam B ₃ of the signal light emitted from the distance measuring device 10 and propagating in the Y direction is still projected onto the object 20.

The signal light projected on the object 20 is reflected by the object 20. Of the reflected signal light, the light beam C ₁ included in the expected angle of the light receiving unit 400 is incident on the distance measuring device 10 from the light receiving unit 400 and propagates in the (−Y) direction as a light beam C ₂ . Light C ₂ is eventually detected in the light receiving element 430, the distance measurement unit 500 displays toward the distance D _L calculated based on the propagation time of the signal light to a user.

FIG. 5 is a schematic diagram for optically explaining another correction operation of the correction unit 300 in the distance measuring device 10. The distance measuring device 10 rotates counterclockwise in the drawing from the state shown in FIG. 2, and has an inclination that forms an angle (−θ ₀ ) with respect to the horizontal plane H. As a result, the front end of the distance measuring device 10 is displaced in the (−Z) direction, and the optical axis of the objective optical system 220 indicates the lower side of the object 20 in the drawing.

In the correction unit 300, the blur detection unit 340 detects the rotation of the distance measuring device 10, and the drive unit 320 displaces the correction member 310 in the (−Z) direction. As a result, the light beam A _{1 that} has propagated horizontally in the (−Y) direction from the object 20 toward the distance measuring device 10 is converted into a light beam A ₂ having the same inclination as the inclination of the distance measuring device 10. Propagate inside. Therefore, the image of the object 20 formed on the eyepiece optical system 110 is not displaced.

As described above, in the distance measuring device 10, even when the distance measuring device 10 is displaced upward or downward with respect to the horizontal plane H, the optical path of the light beam A ₂ propagating through the distance measuring device 10 is corrected by the correction unit 300. The image of the object 20 observed by the user from the collimation unit 100 is not displaced. Further, the optical path of the light beam B ₃ of the signal light projected by the light transmitting unit 200 toward the object 20 is also corrected horizontally and continuously projected onto the object 20. Therefore, even if a displacement due to a user's hand shake or the like occurs, the object 20 can be easily collimated to perform distance measurement.

In the above example, the case where the distance measuring device 13 is shaken in the Z direction has been described. However, when the distance measuring device 13 is shaken in the (−Z) direction, the correction unit 300 can similarly correct the image shake. Of course. Further, since the driving unit 320 displaces the correction member 310 in the X / −X direction perpendicular to the paper surface, the correction unit 300 can also correct the blur in the X / −X direction of the distance measuring device 13.

FIG. 6 is a diagram schematically showing a spot image of signal light formed on the light receiving element 430. As described with reference to FIG. 2, when the distance measuring device 10 is in a horizontal state, the spot image 432 formed in the light receiving region 431 of the light receiving element 430 by the signal light reflected by the object 20 is Located in the approximate center.

Here, the distance measuring device 10, when the upward displacement as shown in FIG. 4, the optical path of the light beam B ₃ of the signal light is projected onto the object 20 are still horizontally maintained. Therefore, the light beam C ₂ incident on the light receiving element 430 also propagates in the distance measuring apparatus 10 substantially horizontally, reflecting the horizontal optical path of the light beam B ₃ .

However, the light receiving element 430 that receives the light beam C ₂ is displaced downward with the inclination of the distance measuring device 10. For this reason, the light ray C ₂ forms a spot image 434 at an offset position on the upper end side in the light receiving region 431 of the light receiving element 430.

Even when the distance measuring device 10 is displaced downward as shown in FIG. 5, the light ray C ₂ incident on the light receiving element 430 propagates in the distance measuring device 10 substantially horizontally. However, the light receiving element 430 that receives the light beam C ₂ is displaced upward with the inclination of the distance measuring device 10. For this reason, the light beam C ₂ forms a spot image 436 at a biased position on the lower end side in the light receiving region 431 of the light receiving element 430.

Thus, when the correction unit 300 performs the correction operation, the position where the signal light forms a spot image in the light receiving element 430 changes. In the distance measuring device 10, the correction range by the correction unit 300 is limited to a range in which the light receiving element 430 can detect the signal light. Thereby, even when the correction unit 300 is operated, the state in which the distance measuring device 10 can execute the distance measuring operation is continued.

FIG. 7 is a schematic diagram for explaining conditions regarding the range in which the signal light used for ranging is displaced. FIG. 7 is a diagram showing a relative relationship between the light receiving range, the irradiation range, and the like, and does not show the sizes of the light receiving range and the irradiation range. In the same figure, when the image stabilization angle indicating the range in which the signal light is displaced by the correction operation is represented by θv, the light receiving angle indicating the light receiving range of the light receiving element 430 is represented by θR, and the irradiation range of the signal light is represented by θL. Show the relationship.

As shown in the middle part of the figure, the conditions when the light receiving element 430 can receive all the signal light are as shown in the following formula 1.
θv + θL ≦ θR
θv ≦ | θR−θL | (Formula 1)

Further, as shown in the lower part of the figure, the conditions when the light receiving element 430 can receive even part of the signal light are as shown in the following Expression 2.
θv-θL <θR
θv <θR + θL (Formula 2)

Therefore, in the distance measuring device 10, the correction unit 300 performs the correction operation so that the optical path of the signal light is displaced within a range that satisfies at least the above-described Expression 2. In addition, when the correction unit 300 displaces the optical path of the signal light within a range that satisfies the above formula 1, since the high signal intensity is detected from the light receiving element 430, the ranging operation is reliably performed.

Furthermore, the optical path of the signal light may be displaced between the condition of the above expression 2 and the condition of the above expression 1, for example, a range in which the light receiving element 430 detects half of the total signal light intensity. Thus, the range in which the correction unit 300 displaces the signal light may be determined based on the signal intensity of the signal light detected by the light receiving element 430.

In order to make full use of the correction range of the correction member 310, as shown in FIG. 7, in any of the above-described configurations, the center of the image stabilization angle θv indicating the range in which the signal light is displaced by the correction operation, and the light reception It is preferable to perform the image stabilization operation so that the center of the light receiving angle θR indicating the light receiving range of the element 430 coincides.

The correction range can be limited by restricting the amount of displacement of the correction member 310, for example. The displacement amount of the correction member 310 may regulate the range of the command of the drive unit 320 generated by the correction control unit 330. In addition, the driving unit 320 or the correction member 310 may be provided with mechanical or electrical restrictions.

In the correction unit 300, the correction control unit 330 may execute a process of limiting the detection result detected by the shake detection unit 340. For example, when high detection accuracy is required according to the application of the distance measuring device 10, the size of the shake detected by the shake detection unit 340 is limited, and the resources of the shake detection unit 340 are allocated to the detection resolution. Good. In this case, the blur detection unit 340 does not detect a blur amount exceeding a predetermined range.

Alternatively, for the purpose of detecting a larger shake, the correction control unit 330 may lower the resolution of the shake detection unit 340 when detecting a shake. Further, the correction control unit 330 restricts the resolution of the blur detection unit 340 to be high in the range where the blur amount to be detected is small and to decrease the resolution of the blur detection unit 340 as the blur amount to be detected increases. Also good.

As described above, when the correction unit 300 performs the correction operation, the spot image of the signal light is shifted in the light receiving region 431 of the light receiving element 430. Therefore, in the distance measuring apparatus 10 including the correction unit 300, it is preferable to leave a margin that allows a transition when the correction operation is performed around the spot image when the correction operation is not performed. From such a viewpoint, when the calibration unit 600 calibrates the distance measurement range, it is preferable to calibrate in consideration of a margin due to the correction operation.

Further, at least at the time of factory shipment, the distance measuring device 10 has a reflecting surface orthogonal to the optical axis of the signal light as a collimation target, and the spot image of the signal light when the correction member 310 is positioned at the center of the moving range. Is preferably adjusted so as to be positioned at the center of the light receiving region 431 of the light receiving element 430. Thereby, the correction range by the correction unit 300 can be expanded isotropically.

Further, when the distance measuring device 10 greatly exceeds the range that can be corrected by the correction unit 300, the correction cannot be performed, or the signal light may be deviated from the object 20 for distance measurement. A warning unit that warns the user may be provided in the distance measuring device 10. In such a case, the correction control unit 330 may stop driving the correction member 310 by the driving unit 320 and interrupt the correction operation until the shake detected by the shake detection unit 340 is settled.

In addition, when the blur detection unit 340 detects that the blur exceeding the limit that can be corrected is settled, the correction for the blur may be resumed. Further, when the drive unit 320 is not driving the correction member 310, the displacement of the correction member 310 may be locked electrically or mechanically. Further, when the correction member 310 is locked, the position of the correction member 310 may be forcibly returned to the center of the movement range.

Further, the correction control unit 330 may start the correction operation with the position of the correction member 310 when the signal light spot image 434 is formed at the center of the light receiving region 431 as the initial position of the correction member 310. The initial position of the correction member 310 may be adjusted when the distance measuring device 10 is shipped, or may be adjusted immediately before starting the distance measurement. Thereby, the correction | amendment part 300 can perform correction | amendment operation | movement in a wide correction | amendment range using the whole surface of the light-receiving area | region 431. FIG.

Furthermore, in the above example, the case where the distance measuring device 10 swings in the Z / −Z direction has been described. However, the drive unit 320 also includes an actuator that displaces the correction member 310 in the X / −X direction perpendicular to the paper surface. Thereby, the correction unit 300 can also correct the blur in the X / −X direction of the distance measuring device 10.

Furthermore, the displacement of the distance measuring device 10 in any direction can be corrected by combining the correction in the Z / −Z direction and the correction in the X / −X direction. Further, the correction unit 300 may perform another correction by providing another drive unit that swings the correction member 310 and swinging the correction member 310.

Of course, the shape of the light receiving region 431 of the light receiving element 430 is not limited to a rectangle. Rather, considering that the correction range by the correction unit 300 is defined as the shape of the light receiving region 431, the shape of the light receiving region 431 may be a circle having a uniform interval from the center to the edge. Thereby, the correction | amendment range by the correction | amendment part 300 can be made equal about all the surroundings. Further, an optical member having a positive refractive index may be provided in front of the light receiving element 430 so that the signal light ray C ₂ is condensed on the light receiving element 430.

FIG. 8 is a schematic diagram for explaining another correction operation of the correction unit 300 in the distance measuring device 10. The distance measuring device 10 further rotates counterclockwise in the drawing from the state shown in FIG. 6 to produce an inclination that forms a larger angle (−θ ₁ ) with respect to the horizontal plane H. As a result, the front end of the distance measuring device 10 is displaced in the (−Z) direction, and the optical axis of the objective optical system 220 points downward in the drawing of the object 20.

In the correction unit 300, the blur detection unit 340 detects the rotation of the distance measuring device 10, and the drive unit 320 displaces the correction member 310 in the (−Z) direction. As a result, the light ray A ₁ that propagates horizontally in the (−Y) direction from the object 20 toward the distance measuring device 10 is inclined to the same side as the inclination of the distance measuring device 10. However, when the inclination of the distance measuring device 10 increases, the position of the spot image formed by the signal light in the light receiving element 430 reaches the end of the light receiving region 431.

The correction unit 300 in the distance measuring device 10 performs a correction operation in a range where the light receiving element 430 receives the signal light. Therefore, when the spot image of the signal light reaches the end of the light receiving region 431, the displacement of the correction member 310 is stopped. Therefore, the image of the object 20 formed on the eyepiece optical system 110 is displaced upward. Along with this, the projection position of the signal light projected as the light beam B ₃ is also displaced downward with respect to the object 20.

Thereby, the light receiving element 430 continues to receive a signal light reflected by a different position of the target object 20 or by the different target object 20 and continue the distance measurement possible state. As described above, since the distance measuring device 10 includes the correction unit 300, the distance measuring function is maintained even when a large displacement occurs.

The distance measurement control unit 520 may notify the outside through the display unit 530 when the correction amount calculated by the clock unit 510 exceeds the movement range of the correction member 310. Thereby, the user is encouraged to hold the distance measuring device 10 stably, and the burden on the correction unit 300 can be reduced.

FIG. 9 is a flowchart showing a control procedure of the correction control unit 330 that controls the operation of the correction unit 300 as described above. When the correction unit 300 starts the correction operation, the correction control unit 330 determines whether or not the blur detection unit 340 has detected the blur of the distance measuring device 10 (step S201).

When the correction unit 300 starts operating, the correction control unit 330 monitors whether or not the shake detection unit 340 has detected a shake (step S201) and waits (step S201: NO). When the shake detection unit 340 detects a shake of the distance measuring device 10 (step S201: YES), the correction control unit 330 calculates a driving amount of the correction member 310 that can cancel the detected shake, that is, a correction amount. (Step S202).

Next, when the correction member 310 is displaced based on the calculated correction amount, the correction control unit 330 determines whether the correction member 310 is not displaced beyond the correction limit (step S203). The correction limit means a limit where the

spot light

432, 434, 436 formed by the signal light in the light receiving unit 400 is deviated from the light receiving region of the light receiving element 430 when the

spot image

432, 434, 436 is moved by the movement of the correction member 310.

Therefore, as already described with reference to FIG. 7, the anti-vibration angle indicating the range in which the signal light is displaced is represented by θv, the light receiving angle indicating the light receiving range of the light receiving element 430 is represented by θR, and the irradiation range of the signal light is represented by θL. In this case, for example, satisfying the condition shown in Equation 1 determines the correction limit. As already described with reference to FIG. 7, the correction limit is not a limit at which the

spot images

432, 434, and 436 completely go out of the light receiving region of the light receiving element 430, but as shown in Equation 2, You may determine in the position where a part of spot image remains in a light reception area | region. Thereby, when the correction member 310 reaches the correction limit, the light receiving element 430 still receives the signal light, and the state in which the distance can be measured is continued.

Further, as the correction limit referred to by the correction control unit 330, a predetermined value may be held in the correction control unit 330. The correction limit value may be stored in a storage unit that can be referred to by the correction control unit 330.

If it is found in step S203 that the correction member 310 remains within the correction limit even if the correction member 310 is moved by the calculated correction amount (step S203: YES), the correction control unit 330 will correct the correction member 310 according to the calculated correction amount. Is transmitted to the drive unit 320 (step S204). Thereby, the blur detected by the blur detection unit 340 is corrected by the correction member 310, and image blur is prevented in the image of the object 20 observed through the eyepiece optical system 110.

Also, the signal light emitted from the light transmitting unit 200 does not deviate from the target 20 that is initially collimated. Furthermore, since the signal light reflected by the object 20 is maintained in the light receiving element 430, the distance measuring unit 500 can measure the distance from the distance measuring device 10 to the object 20. Will continue.

On the other hand, when the calculated correction amount is to move the correction member 310 beyond the correction limit in step S203 (step S203: NO), the correction control unit 330 stops the blur correction by the correction member 310. Then, the correction member 310 is returned to the initial position (step S205). As a result, image blurring of the object 20 occurs in the collimation unit 100 and signal light may be projected onto something other than the object 20. However, the state in which the distance measuring device 10 can perform distance measurement is maintained.

Next, the correction control unit 330 adjusts the time interval when the shake detection unit 340 periodically detects the shake of the distance measuring device 10 (step S206). That is, when the correction unit 300 can correct the shake of the distance measuring device 10 by a series of correction operations from step S201 to step S204, for example, the detection interval of shake is made longer and the process from step S202 to step S204 is performed. The number of correction operations may be reduced. Thereby, the power consumption by the correction unit 300 can be suppressed.

Further, when the continuous correction operation of the correction unit 300 is interrupted by the operation from step S201 to step S205, for example, the correction operation per unit time from step S202 to step S203 is shortened by reducing the blur detection interval. The number of times may be increased. Thereby, it is possible to increase the possibility that an effective correction operation can be completed before the correction amount reaches the correction limit. Needless to say, the adjustment of the interval in step S206 includes the case where the correction interval is not changed.

Next, the correction control unit 330 determines whether or not the instruction for causing the correction unit 300 to perform the correction operation is still valid (step S207). As a result, when the instruction for the correction operation is still valid (step S207: YES), the correction control unit 330 returns to step S201 again and monitors whether or not the blur detection unit 340 has detected the blur. If it is determined in step S207 that the correction operation instruction is invalid (step S207: NO), the correction control unit 330 ends the operation of the correction unit 300.

In the above example, the correction unit 300 in step S203 determines the correction limit with reference to a value prepared in advance. However, for example, an image sensor may be used as the light receiving element 430, and the operation of the driving unit 320 may be limited when the position of the spot image of the signal light approaches the edge of the light receiving region 431. Thereby, the correction limit can be automatically detected without lowering the received light intensity of the signal light by the light receiving element 430.

FIG. 10 is a diagram illustrating an example of a control method of the correction unit 300, and is a schematic diagram illustrating a locus of a spot of the signal light B ₃ irradiated on the object 20 while being displaced by the correction unit 300. By controlling the correction member 310 as shown in the figure in the direction in which the light receiving intensity detected by the light receiving element 430 is high, the range irradiated with the signal light B ₃ can be concentrated on the region where the object 20 exists. . Therefore, the distance measuring operation can be executed reliably and efficiently.

FIG. 11 is a schematic diagram for explaining another correction operation by the correction unit 300. In FIG. 11, the distance measuring device 10 is in a horizontal state as in the state shown in FIG. However, the distance measuring device 10 is close to the short-distance D _S with respect to the object 20, a parallax occurs that can not be ignored between the light transmission unit 200 and the light receiving portion 400 of the distance measuring device 10. Therefore, the incident angle of the light ray _{C 1} is increased with respect to the light receiving portion 400, the incident position of the light beam _{C 2} is displaced with respect to the light receiving element 430.

On the other hand, as described above, the correction unit 300 can displace the correction member 310 within a range that does not exceed the correction limit. Therefore, by displacing the correcting member 310, changing the direction of the optical path in the beam B ₃ of the signal light to be projected in the Y direction toward the target 20, due to the disparity between the light transmitting unit 200 and the light receiving portion 400 It is possible to compensate for a decrease in received light intensity of signal light.

That is, when the distance D _S from the distance measuring device 10 to the object 20 is short, for example, by an instruction to switch the user ranging scope by the switch operation or the like, the optical path of the light beam B ₃ in (-Z) direction Displace. Thereby, the parallax between the light transmission part 200 and the light-receiving part 400 can be relieved, and the light reception efficiency of the signal light in the light receiving element 430 can be improved.

When the correction member 310 is displaced according to the distance as described above, the amount of displacement of the correction member 310 increases as the measurement object approaches the distance measuring device 10. Therefore, the correction control unit 330 may increase the amount of displacement of the correction member 310 when the object 20 approaches the distance measuring device 10 exceeding a predetermined threshold.

Further, by changing the optical path of the light beam B ₃ of the signal light by the correction unit 300, the signal light is reliably received by the light receiving element 430, so that the area of the light receiving region 431 of the light receiving element 430 can be reduced. As a result, the signal-to-noise ratio of the signal light can be increased and the component cost of the light receiving element 430 can be reduced.

It should be noted that it is preferable to move the correction member 310 to a position where the signal light spot image 434 is formed at the center of the light receiving region 431 before starting correction according to the distance to the object 20. Thereby, the correction operation can be executed in a wide correction range by using the entire light receiving region 431 of the light receiving element 430.

FIG. 12 is a schematic diagram for explaining parallax correction in the distance measuring device 10. When the distance measuring device 10 is viewed from the object 20 side, the objective optical system 220 of the light transmitting unit 200 and the objective optical system 410 of the light receiving unit 400 are vertically arranged in front of the distance measuring device 10. .

FIG. 13 is a schematic diagram for explaining the parallax correction effect when the correction unit 300 is arranged in the light transmission unit 200 (corresponding to the configurations of FIGS. 1, 2, 4, 5, 8, and 11). Here, it is assumed that the signal light is a parallel beam and does not spread. In the drawing, “d” indicates an inter-axis distance between the optical axis of the optical system of the light transmitting unit 200 and the optical axis of the optical system of the light receiving unit 400. “Ds” indicates the distance between the distance measuring device 10 and the object 20.

As shown in the drawing, when the correction member 310 is not displaced, the optical path of the signal light in the light transmitting section 200 and the optical path of the signal light in the light receiving section 400 are parallel to each other. On the other hand, when the correction unit 300 is operated and the correction member 310 is displaced, the optical path of the signal light is displaced in the light transmission unit 200, and the optical path of the signal light is tilted to the correction angle θa.

When the optical path of the signal light is inclined on the light transmitting unit 200 side, if the light receiving angle in the light receiving unit 400 is θR, the light receiving unit 400 cannot receive the signal light when the following Expression 3 is not satisfied.
Ds <d / (tan θR + tan θa) (Formula 3)

Therefore, in the distance measuring device 10, when the signal light is tilted to the correction angle θa for parallax correction, the shortest distance Ds at which the signal light can be received by the light receiving unit 400 can be expressed by the following Expression 4.
Ds = d / (tan θR + tan θa) (Formula 4)

Since the spread of the signal light is small relative to the lens diameter of the optical system of the light transmitting unit 200 at a short distance, the spread angle θL of the signal light is ignored. However, when considering the spread angle θL of the signal light, it can be expressed as the following Expression 6 according to the above Expression 5.
tan θR → tan θR + tan θL (Formula 5)

In this case, the above equation 4 can be expressed as the following equation 7.
Ds = d / (tan θR + tan θL + tan θa) (Expression 6)

In the above formulas 5 and 6, assuming that the correction angle θa is a minute angle, the following formula 7 is established.
tan (α + β) = tan α + tan β (Expression 7)

Now, the inter-axis distance d between the optical axis of the light transmitting unit 200 and the optical axis of the light receiving unit 400 is 35 mm, the spread angle θL of the light source light is 0.05 °, and the light receiving angle θR of the light receiving element is 0.5 °. In this case, in order to measure the distance of 2 m from the distance measuring device to the target, the inclination θa of the optical path by the correction member 310 is about 0.46 °. Therefore, the parallax can be corrected by shifting the correction member 310 so that θa is inclined by 0.46 °. When performing parallax correction and blur correction simultaneously, a lens position that tilts the optical path by θa is set as a reference position, and the lens driving range may be limited so as to be symmetric with respect to the reference position.

FIG. 14 is a schematic diagram for explaining the parallax correction effect when the correction unit 300 is arranged in the light receiving unit 400 (corresponding to the configurations of FIGS. 18 and 19). As shown in the figure, even when the correction unit 300 is arranged in the light receiving unit, the expression is similar to the case shown in FIG. 15 except that the direction in which the correction member 310 moves when performing parallax correction is reversed. 7 is established.

FIG. 15 is a schematic diagram for explaining parallax correction in the distance measuring device 10, and shows a case where the light transmitting unit 200 and the light receiving unit 400 are arranged horizontally. Also in the illustrated case, except that the moving direction of the correction member 310 when correcting the parallax is horizontal, Expression 7 is established as in the case shown in FIGS. 13 and 14, and the light transmitting unit 200 In addition, the parallax can be corrected between the light receiving units 400.

As the correction member 312 for correcting the parallax, in addition to the lens described above, a prism or a variable apex angle prism that can change the angle formed by the incident surface and the exit surface can be used. Furthermore, the position of the light emitting unit 210 or the position of the light receiving element 430 may be shifted according to the amount of parallax, that is, the measurement distance.

In addition, in order to perform correction according to the amount of parallax, that is, the measurement distance, the user may instruct to switch the distance measurement range by a switch operation or the like. Alternatively, if distance measurement cannot be performed even when the number of trials reaches the number of trials described above, it is determined that parallax has occurred, and the correction member 310 is in a direction in which reflected light from the object 20 at a closer distance can be received. A distance measurement operation may be performed while scanning, and distance measurement may be performed at a position where the received light intensity increases. By calibrating in this way, parallax can be corrected without a user switching operation.

When the distance from the distance measuring device 10 to the object 20 is sufficiently long and parallax correction is not required, the drive center of the correction member 310 by the correction control unit 330 of the correction unit 300 matches the center of the light receiving unit 400. It is preferable to set so as to.

In addition, when image stabilization is performed in a state where the inclination of the optical path is adjusted to correct parallax, at least the correction control unit 330 of the correction unit 300 uses the correction member 310 as the light of the light transmission unit 200 and the light reception unit 400. It is preferable to displace symmetrically with respect to a vertical line connecting the axes.

In addition, when light in the infrared band or ultraviolet band is used as the signal light, there is a difference in the image stabilization coefficient between the collimation optical system and the light transmission optical system due to chromatic aberration, and there is an angular difference or parallax in the optical axis during image stabilization. Arise. This parallax causes a shift in the position where the signal light is irradiated with respect to the position aimed by the collimating optical system, which is disadvantageous when measuring a small object.

On the other hand, a light emitting surface of a light emitting element such as a light emitting diode forming the light emitting unit 210 has a finite area. For this reason, even when parallel light is transmitted through the light transmission optical system, it has a certain spread angle, that is, a field angle determined by the size of the light emitting surface and the focal length of the light transmission optical system. Therefore, if the parallax is within the range of the spread angle of the signal light beam, the shift between the collimation position and the signal light irradiation position does not cause a problem in practice.

Note that the light emitting surface of the light emitting element generally has a linear shape or a rectangular shape, so that the beam spread angle is not rotationally symmetric even if it is parallel light by the optical system, and the light spreads greatly within one surface. The angle is a small spread angle in a plane perpendicular to the angle. Therefore, the allowable parallax is considered in the plane on the side where the spread is small.

In the change of the optical path by the correction unit 300, when the ratio of the image movement amount on the imaging surface to the movement amount of the moving lens group including the DOE and the liquid crystal lens is set as the image stabilization coefficient k, the signal light is input to the light receiving element 430. The incident condition can be expressed as in Equation 8 below. However, “kd” is a vibration isolation coefficient for the d line of the correction member 310, “kL” is a vibration isolation coefficient for the signal light of the correction member 310, “a” is the length of the minor axis of the light emitting surface of the light emitting unit 210, “S” represents the maximum amount of eccentricity of the correction member 310.
| Kd−kL | s <a (Expression 8)
As described above, when the optical path is changed by the correction unit 300, there may be a difference between the collimation performed in the visible light band and the displacement of the optical path in the signal light. Therefore, when the correction unit 300 is formed, a range in which parallax between the collimation optical system and the light transmission optical system is allowed may be taken into consideration.

Further, the image stabilization coefficient can be expressed as Equation 9 below by using the magnification βv of the correction member 310 and the overall magnification of the lens group on the image side of the correction member 310 as βr.
Anti-vibration coefficient = | (1−βv) × βr | (Expression 9)

In this case, the image plane movement amount of the collimation system is kd · s, where kd is the anti-vibration coefficient of the correction member 310 with respect to the d line, and s is the eccentricity amount of the correction member 310. Similarly, if the image stabilization coefficient for the transmission wavelength of the signal light is kL, the image plane movement amount is kL · s. As shown in Expression 10 below, if the difference in the image plane movement amount is always smaller than half the length of the light emitting element light emitting surface of the light emitting unit 210, the collimation is performed even when the correction member 310 is displaced. The optical axis of the system does not deviate from the light flux of the signal light.
| Kd−kL | s _max <a / 2 (Expression 10)
However, “s _max ” indicates the maximum eccentricity of the correction member 310.

Further, in the correction unit 300, it is preferable that the following

expressions

11 and 12 are satisfied, where θv is the image stabilization coefficient kd for the d line of the correction member 310 and the maximum camera shake correction angle of the correction member 310.
1.2 <kd <2.2 (Formula 11)
0.3 <θv <0.7 (Expression 12)

As a means for decentering the lens in the vertical direction, many mechanisms are currently used so as to surround the outer periphery of the optical element, and if it falls below the lower limit, it is necessary to obtain a practically sufficient camera shake compensation angle. Since the amount of eccentricity of the optical element increases, the diameter of the eccentric mechanism must be increased, resulting in an increase in the size of the laser rangefinder housing. For example, when the image stabilization coefficient kd is 1.2 and the objective focal length is 100 mm, an eccentricity s of 0.44 mm is set to achieve a correction angle θv of 0.3 °. Therefore, by satisfying the above equation 11, the size of the correction unit 300 can be prevented from increasing.

In addition, if the vibration-proof coefficient kd in the said Formula 11 exceeds said upper limit, the sensitivity of the correction | amendment part 300 will become high too much and manufacture will become difficult. That is, when the distance to the distant object 20 is regarded as infinity and the collimation unit 100, the light transmitting unit 200, and the light receiving unit 400 are mutually independent, the signal light reflected by the object 20 is received. Is required to make the optical axis of the light transmitting unit 200 and the optical axis of the light receiving unit 400 parallel to each other.

However, when the sensitivity of the correction unit 300 is too high, there is a possibility that the optical axis of the light transmission unit 200 is deflected due to the deviation of the center position during manufacturing and the signal light cannot be received. For this reason, when the position of the optical element of the correction unit 300 is adjusted at the time of manufacture, the adjustment takes time due to the sensitivity being too high.

Further, in the above equation 12, when the correction angle θv deviates from the above range, a sufficient correction angle cannot be obtained or the correction unit 300 is enlarged. For example, when the image stabilization coefficient kd is 2.2 and the objective focal length is 100 mm, an eccentricity s of 0.56 mm is set to achieve a correction angle θv of 0.7 °. Therefore, by satisfying the above equation 12, the size of the correction unit 300 can be prevented from increasing.

FIG. 16 is a schematic cross-sectional view of the distance measuring device 11 including another correction unit 301. The distance measuring device 11 has the same structure as the distance measuring device 10 shown in FIG. 1 except for the structure of the correction unit 301 described below. Therefore, common elements are denoted by the same reference numerals, and redundant description is omitted.

The correction unit 301 of the distance measuring apparatus 11 includes a correction member 312 and a drive unit 322 arranged in the light receiving unit 400 in addition to the correction member 310 and the drive unit 320 arranged in the light transmission unit 200. The correction member 312 of the light receiving unit 400 includes a lens that forms part of the optical system of the light receiving unit 400.

Under the control of the correction control unit 330, the drive unit 322 displaces the correction member 312 in a direction that intersects the optical axis of the correction member 312. Thereby, the optical path of the light beam C ₂ propagating in the (−Y) direction through the distance measuring device 10 can be changed, and the position where the spot image of the signal light is formed in the light receiving element 430 can be changed.

In the correction unit 301, the drive unit 322 may be controlled in common by a correction control unit 330 that controls the drive unit 320. Thereby, the correction member 312 can be displaced in synchronization with the correction member 310. Here, “displaced synchronously” means that the pair of

correction members

310 and 312 are moved simultaneously, and that the change in the optical path caused by the movement of the

correction members

310 and 312 is also supported. To do.

A lens or a prism can be used as the auxiliary correction member 312. In addition, a variable apex angle prism that can change the angle formed by the entrance surface and the exit surface can be used.

FIG. 17 is a schematic diagram for explaining the correction operation of the correction unit 301. The distance measuring device 10 rotates clockwise from the state shown in FIG. 2 to produce an inclination that forms an angle (+ θ ₀ ) with respect to the horizontal plane H. Thereby, the front end of the distance measuring device 10 is displaced in the Z direction, and the optical axis of the objective optical system 220 points upward in the drawing of the object 20.

In the correction unit 301, the blur detection unit 340 detects the rotation of the distance measuring device 10, and the driving unit 320 displaces the correction member 310 in the Z direction. As a result, the light beam A _{1 that} has propagated horizontally in the (−Y) direction from the object 20 toward the distance measuring device 10 is converted into a light beam A ₂ having the same inclination as the inclination of the distance measuring device 10. Propagate inside. Therefore, the image blur in the collimation unit 100 is corrected. Further, the projection direction of the signal light projected from the objective optical system 220 is also corrected and does not change.

Signal light projected onto the object 20 is reflected by the object 20, enters the light receiving portion 400 in part as ray C _1, after being corrected propagation path by correcting member 312, measured as ray C ₂ It propagates in the distance device 10. The corrected optical path of the light beam C ₂ is parallel to the light beam A ₂ in the collimation unit 100 and the light beam B ₂ in the light transmission unit 200, and the light beam B ₂ is a spot image at the approximate center of the light receiving region 431 of the light receiving element 430. Form. Thereby, the distance measuring unit 500 displays the distance calculated based on the propagation time of the signal light toward the user.

As described above, in the distance measuring device 11, the propagation optical path of the light beam C ₂ in the light receiving unit 400 is parallel to the light beam A ₂ in the collimation unit 100 and the light beam B ₂ in the light transmission unit 200 by correction by the correction unit 301. It is corrected. Therefore, in the same manner that the displacement of the image of the collimation unit 100 is corrected by the correction member 310, and in the same way as the projection direction of the signal light in the light transmitting unit 200 is corrected, in the light receiving unit 400, The position of the spot image of the signal light in the light receiving element 430 is corrected. Therefore, the correction range of the correction unit 301 is not limited by the light receiving range of the signal light by the light receiving element 430.

In the above example, the correction member 310 of the light transmitting unit 200 and the correction member 312 of the light receiving unit 400 are displaced in synchronization. However, the

correction members

310 and 312 may be controlled individually without fixing the

correction members

310 and 312 in a period in which one of the

correction members

310 and 312 is displaced. For example, when the signal light spot image reaches the end of the light receiving range of the light receiving element 430, the correction member 312 on the light receiving unit 400 side is driven when the correction operation is initially performed by the correction member 310 on the light transmitting unit 200 side. May be. Thus, in effect, the same correction range as in the above example can be achieved, and power can be saved as much as the displacement of one correction member 312 is reduced.

Further, for example, while the camera shake correction is performed using the correction member 310 and the driving unit 320 on the light transmitting unit 200 side, the parallax correction is performed using the correction member 312 and the driving unit 322 on the light receiving unit 400 side. Good. In this case, the correction member 312 on the light receiving unit 400 side is not displaced with respect to camera shake correction, and the correction member 310 on the light transmission unit 200 side is not displaced with respect to parallax correction. Thereby, it is possible to maintain high ranging accuracy particularly for the object 20 at a short distance while preventing image blur.

Further, when the shake correction and the parallax correction are performed together, the shake correction is performed using the correction member 310 and the drive unit 320 on the light transmission unit 200 side in the stage of collimating the object 20, and the user performs When the start of distance measurement is instructed, the camera shake correction may be stopped, and the parallax correction may be performed using the correction member 312 and the driving unit 322 on the light receiving unit 400 side. As a result, it is possible to achieve both prevention of image blur and improvement of distance measurement accuracy while suppressing the peak value of power consumption.

FIG. 18 is a schematic cross-sectional view of the distance measuring device 12 including another correction unit 302. The distance measuring device 12 has the same structure as the distance measuring device 10 shown in FIG. 1 and the distance measuring device 11 shown in FIG. 16 except for the structure of the correction unit 302 described below. Therefore, common elements are denoted by the same reference numerals, and redundant description is omitted.

The correction unit 302 of the distance measuring device 12 does not include the correction member 310 in the collimation unit 100 and the light transmission unit 200, but includes a correction member 312 and a driving unit 322 arranged in the light receiving unit 400. The correction member 312 includes a lens that forms part of an afocal optical system included in the light receiving unit 400.

The drive unit 322 displaces the correction member 312 in a direction that intersects the optical axis of the correction member 312. Thereby, the optical path of the light beam C ₂ propagating in the (−Y) direction through the distance measuring device 10 can be changed, and the position where the spot image of the signal light is formed in the light receiving element 430 can be changed. The drive unit 322 is controlled by a correction control unit 330 that refers to the output of the shake detection unit 340.

FIG. 19 is a schematic diagram for explaining the correction operation of the correction unit 302. The distance measuring device 12 is in a horizontal state as in the state shown in FIG. On the other hand, the object 20 is approaching the distance measuring device 10, and a disparity that cannot be ignored occurs between the light transmitting unit 200 and the light receiving unit 400 of the distance measuring device 10. Therefore, the parallax correction described in the description of FIG. 14 is performed.

Further, the correcting member 312, so that the signal light is received by the light receiving element 430, it is possible to change the optical path of the light beam C _2, it is possible to reduce the area of the light receiving region 431 of the light receiving element 430 to implement. As a result, the signal-to-noise ratio of the signal light can be increased and the component cost of the light receiving element 430 can be reduced. Note that with the above structure, the light receiving element 430 can receive signal light over a wide range of incident angles. Therefore, it is preferable to radiate the signal light emitted from the light transmitting unit 200 at a wide angle and irradiate the signal light over a wide range including the object 20.

As described above, the correction unit 300 can be used for parallax correction when the distance to the object 20 is short. Furthermore, both the correction of the displacement of the distance measuring device 10 due to camera shake and the correction of the parallax due to the position of the object 20 may be executed together.

In the series of

distance measuring devices

10, 11, and 12 described above, the correction operation by the correction units 300, 301, and 302 may be changed according to the state of the distance measuring device 10. That is, for example, during a period in which the user collimates the object 20, the correction range may be increased to make it easier to supplement the object 20.

On the other hand, when the distance measuring unit 500 starts a distance measuring operation, the correction operation may be temporarily suppressed or stopped for the purpose of suppressing a difference in optical conditions between the light transmitting unit 200 and the light receiving unit 400. Since the time required for one distance measurement operation is short, even if the correction operation is interrupted according to the execution of the distance measurement operation, the collimating unit 100 has little influence on the image observed by the user.

One of the causes of the displacement of the distance measuring device 10 is a user's hand shake. However, there are various patterns of camera shake, and a single correction algorithm is not always effective. Therefore, a plurality of correction algorithms executed by the correction control unit 330 may be prepared, and the correction algorithm may be switched according to the blur pattern detected by the blur detection unit 340.

More specifically, the correction algorithm executed by the correction control unit 330 may be switched when at least one of the amplitude and frequency of blur detected by the blur detection unit 340 exceeds a predetermined threshold. More specifically, an operation mode in which the correction range by the correction unit 300 is narrowed may be provided with emphasis on suppression of distance measurement time and power consumption.

On the other hand, assuming a user who is not familiar with the operation of the distance measuring device 10, the operation mode is to widen the correction range as much as possible and to display a message indicating a careful operation of the user when the correction limit is reached. May be provided. The operation mode may be switched according to the user's selection, or may be switched automatically as determined by the correction control unit 330, the distance measurement control unit 520, or the like.

Further, in step S201, when the period during which no blur is detected continues beyond a predetermined time, the correction unit 300 or the entire distance measuring device 10 may be shifted to a state in which power consumption is suppressed.

Furthermore, in the above example, the

correction members

310 and 312 are provided in the objective

optical systems

220 and 410. However, for example, a part or all of the erecting prism 130 can be used as the correction member 310. A part of the eyepiece optical system 110 can also be used as the correction member 310. Furthermore, when a liquid crystal display panel or the like is used for the collimation unit 100, an electronic correction member can also be used.

The correction units 300, 301, and 302 as described above may be provided with a switch for switching on / off so that the distance measurement device 10 can perform distance measurement without a correction operation. Thereby, when the target object 20 is located nearby and is easy to collimate, the operation of the correction units 300, 301, and 302 can be stopped at the user's will to save the power of the distance measuring device 10.

FIG. 20 is a schematic cross-sectional view of the distance measuring device 13. The distance measuring device 13 includes a collimation unit 100, a light transmitting unit 200, a calibration unit 600, a light receiving unit 400, a distance measuring unit 500, and a correction unit 300. In the following description, the side on which the collimation unit 100 is disposed is the rear side of the distance measuring device 13. Further, the side facing the object of distance measurement is the front side of the distance measuring device 13.

The collimation unit 100 includes an eyepiece optical system 110, a reticle plate 120, and an erecting prism 130. The collimation unit 100 shares the objective optical system 220 with the light transmission unit 200. The collimation unit 100 shares the correction member 310 with the calibration unit 600 and the correction unit 300.

The rear end of the eyepiece optical system 110 is exposed on the rear end surface of the distance measuring device 13. The front end of the eyepiece optical system 110 faces the rear end of the erecting prism 130 inside the distance measuring device 13. The user of the distance measuring device 13 collimates the object by visually recognizing the image of the object through the eyepiece optical system 110.

Note that an optical member that changes the imaging position of the eyepiece optical system 110 in the optical axis direction may be provided as a part of the eyepiece optical system 110 or in addition to the eyepiece optical system 110. Thereby, it is possible to make the user observe a clear image regardless of the distance to the object. Moreover, diopter correction can be performed according to the user's visual acuity.

The reticle plate 120 has a reticle formed by printing, etching or the like on a plate transparent to visible light. The reticle has a collimation index having a shape such as a crosshair, a rectangular frame, or a circular frame, and is arranged in a field of view formed by the eyepiece optical system 110. As the reticle plate 120, a transmissive liquid crystal display panel that displays a reticle as an image may be used.

The light transmitting unit 200 includes a light emitting unit 210 and an objective optical system 220. Further, the light transmission unit 200 shares a part of the erecting prism 130 including the dichroic reflection surface 132 and the total reflection surface 134 with the collimation unit 100. Furthermore, as already described, the correction member 310 is shared with the calibration unit 600 and the correction unit 300.

The light emitting unit 210 includes a light emitting element such as a semiconductor laser as a light source, and generates pulsed signal light when the distance measuring device 13 performs a distance measuring operation. In the present embodiment, the signal light is, for example, infrared light.

Note that the wavelength of the signal light may be other than the visible light band, for example, ultraviolet rays. When the signal light is ultraviolet light, the dichroic reflecting surface 132 of the erecting prism 130 reflects the visible light band and transmits the ultraviolet light band. The total reflection surface 134 reflects the visible light band and the ultraviolet band.

The objective optical system 220 is arranged at the front end of the distance measuring device 13, and the front end face is opposed to the object to be measured. The rear end face of the objective optical system 220 faces the front end face of the erecting prism 130 with the correction member 310 interposed therebetween. The objective optical system 220 and the correction member 310 cooperate to form a light transmission optical system.

An optical member that changes the imaging position of the objective optical system 220 in the optical axis direction may be provided as a part of the objective optical system 220 or in addition to the objective optical system 220. As a result, a clearer image can be observed in the collimation unit 100, and an object to be measured can be selected with high accuracy by reducing the beam diameter of the signal light.

The calibration unit 600 and the correction unit 300 share the correction member 310 and the drive unit 320 with each other. The correction member 310 forms an optical system together with the eyepiece optical system 110 and the objective optical system 220. The drive unit 320 displaces the correction member 310 in a direction that intersects the optical axis of the correction member 310. Further, the drive unit 320 may swing the correction member 310 in the direction in which the main surface swings.

As the correction member 310, a displacing lens or a oscillating prism can be used. In addition, a variable apex angle prism that can change the apex angle formed by the incident surface and the exit surface by swinging a member that forms the entrance surface or the exit surface can also be used as the correction member 310. The drive unit 320 includes an actuator such as a voice coil motor or a piezoelectric motor that can electrically control the drive amount.

The light receiving unit 400 includes an objective optical system 410, a band transmission filter 420, and a light receiving element 430. The objective optical system 410 has an optical axis different from that of the objective optical system 220 of the light transmitting unit 200 to form a light receiving optical system.

In the light receiving unit 400, a band transmission filter 420 and a light receiving element 430 are sequentially arranged behind the objective optical system 410. The band transmission filter 420 has a characteristic of transmitting light in a narrow band including signal light and blocking or attenuating light in other bands. The light receiving element 430 includes a photoelectric conversion element such as a photodiode or a phototransistor having sensitivity to a band of signal light. Thereby, the light receiving element 430 detects the incident signal light and generates an electrical signal corresponding to the detected signal light.

In addition, it is preferable that the light receiving area of the light receiving element 430 is smaller from the viewpoint of eliminating the influence of background light in detecting signal light. Further, an optical member that changes the imaging position of the optical system in the optical axis direction may be provided as part of the objective optical system 410 or in addition to the objective optical system 410. Thereby, a small spot light can be received by the light receiving element 430 by reducing the beam diameter of the received signal light.

In the distance measuring device 13 having the structure as described above, among the light reflected or scattered from the object positioned in front of the distance measuring device 13, the light ray A ₁ propagating within the range of the prospective angle of the objective optical system 220. Is incident through the objective optical system 220. The light ray A ₁ passes through the correction member 310, propagates backward as the light ray A ₂ through the distance measuring device 13, and passes through the erecting prism 130, the reticle plate 120, and the eyepiece optical system 110, and passes through the distance measuring device 13. It is emitted as light a ₃ rearward. Thereby, the user can observe an erect image of the object through the eyepiece optical system 110.

The reticle arranged on the reticle plate 120 is superimposed on the image of the object observed by the user through the eyepiece optical system 110. Therefore, the user can collimate the object with the distance measuring device 13 by displacing the distance measuring device 13 to make the reticle coincide with the object.

The user of the distance measuring device 13 instructs the distance measuring device 13 to start a distance measuring operation by operating a switch such as a button provided on the distance measuring device 13, for example. When the user instructs the distance measuring device 13 to perform distance measurement, the light emitting unit 210 emits pulsed signal light as the light beam B ₁ toward the upper surface of the erecting prism 130 in the drawing. In the erecting prism 130, the signal light passes through the dichroic reflecting surface 132, is reflected by the total reflecting surface 134, and propagates forward in the distance measuring device 13 as the light beam B ₂ .

Further, the signal light is projected outside through the correction member 310 and the objective optical system 220 toward the front of the distance measuring device 13 as the light beam B ₃ . Signal light projected as rays B ₃ is projected to the object of distance measurement that is collimated. Assuming that the distance to the object to be measured is several hundred meters, the spread of the projected signal light is, for example, about ± 0.05 °.

The correction member 310 transmits the light beam A ₂ incident on the inside of the distance measuring device 13 and the light beam B ₂ emitted from the distance measuring device 13 in the vicinity of the objective optical system 220. When the optical axis of the correction member 310 is displaced by being driven by the driving unit 320, the optical paths of the light beams A ₂ and B ₂ are displaced, and the propagation directions thereof are changed.

By propagation direction of the light ray A ₂ is displaced, the image for the user to observe through the collimating section 100 is displaced. In other words, the displacement of the image observed by the user can be stopped by appropriately displacing the correction member 310 when the distance measuring device 13 is displaced.

When the optical axis of the correcting member 310 is displaced, the propagation direction of the light beam B ₂ is displaced. Thus, the propagation direction of the light beam B ₃ of the signal light projected to the outside is displaced. Therefore, when the distance measuring device 13 is displaced, the signal light irradiation target can be maintained by appropriately displacing the correction member 310.

A light beam C ₁ reflected or scattered from an object positioned in front of the distance measuring device 13 is incident on the objective optical system of the light receiving unit 400. The light beam C ₁ propagates backward as the light beam C ₂ through the distance measuring device 13, passes through the band-pass filter 420, and is received by the light receiving element 430.

Therefore, the light receiving element 430 detects the signal light included in the incident light beams C ₁ and C ₂ with a high S / N ratio and generates an electrical signal. The electric signal generated by the light receiving element 430 is input to the distance measuring unit 500.

In addition, although the single drive part 320 is described in the figure, the other drive part 320 which changes the correction member 310 in the direction which cross | intersects with respect to a paper surface is also provided together. Thus, the correcting member 310, in a plane intersecting the propagation optical axis of the light beam C ₂ can be displaced in two dimensions.

The ranging unit 500 includes a clock unit 510, a ranging control unit 520, and a display unit 530. The clock unit 510 measures the time taken from when the light transmitting unit 200 transmits the signal light to when the signal light reflected by the object is received.

The ranging control unit 520 comprehensively controls the ranging operation in the ranging device 13. The objects to be controlled by the distance measurement control unit 520 include the light emitting unit 210 of the light transmission unit 200 and the like. Further, the distance measurement control unit 520 calculates the distance between the distance measurement device 13 and the object based on the time measured by the clock unit 510.

When the distance measuring device 13 has a function of detecting an inclination or the like, the distance measuring control unit 520 may calculate a horizontal distance to the object, a height difference, and the like. Further, the clock unit 510 may correct the calculation result based on environmental changes such as temperature.

The display unit 530 has a liquid crystal display panel and the like, and shows the calculation results of the distance measurement control unit 520 such as the distance to the object, etc., by characters, images, and the like. The display unit 530 may display the remaining battery amount, an error message, a clock, and the like in addition to the distance measurement result.

Further, the display unit 530 displays a message for urging the user to hold the distance measuring device 13 when the amplitude or frequency of blur detected by the blur detection unit 340 described later exceeds a predetermined threshold. May be. Thereby, the burden of the calibration part 600 can be reduced and the power consumed by the distance measuring device 13 can be reduced.

The calibration unit 600 includes a calibration control unit 630, an intensity measurement unit 640, and a storage unit 650. Further, the calibration unit 600 shares the drive unit 320 with the correction unit 300.

The intensity measurement unit 640 refers to the output signal of the light receiving element 430 and measures the light intensity of the signal light received by the light receiving element 430. Note that the clock unit 510 of the distance measuring unit 500 detects temporal timing when the light receiving element 430 receives the signal light. On the other hand, the intensity measurement unit 640 measures whether or not a light intensity higher than a predetermined threshold value is detected, for example.

The calibration control unit 630 sends a command to the drive unit 320 to shift the correction member 310. In addition, the calibration control unit 630 specifies the drive amount of the correction member 310 by the drive unit 320 when the light intensity measured by the intensity measurement unit 640 exceeds the threshold value. Further, the calibration control unit 630 stores the specified driving amount of the correction member 310 in the storage unit 650 and saves it.

As described above, the correction unit 300 that corrects the image blur generated in the collimation unit 100 and the light transmission unit 200 can be formed by using the correction member 310 and the drive unit 320 that form part of the calibration unit 600. Since the calibration operation and the distance measuring operation are not executed simultaneously, the use efficiency of parts in the distance measuring device 10 can be improved by the structure as described above.

FIG. 21 is a diagram schematically showing a spot image of signal light formed on the light receiving element 430. As described above, when the distance from the distance measuring object 20 to the distance measuring device 13 changes, the signal light reflected by the object 20 forms a spot image 432 formed on the light receiving region 431 of the light receiving element 430. The position of 434 changes.

For example, as shown in FIG. 2, when the object 20 is in the furthest distance D _L from the distance measuring device 13, the spot image 432 of the signal light is formed in the drawing the upper end side of the light-receiving region 431. Further, as shown in FIG. 11, when the object 20 is in a close distance D _S from the distance measuring device 13, the spot image 434 of the signal light is formed in the figure the lower end of the light-receiving region 431.

Further, when the object 20 is closer to the distance measuring device 13 than in the state shown in the drawing, the signal light spot image 434 moves below the light receiving region 431 and is no longer received by the light receiving element 430. Therefore, the position at which the spot image 434 reaches the lower end of the light receiving region 431 in the figure is the distance measuring limit of the distance measuring device 13.

In view of such a structure of the distance measuring device 13, when calibrating the optical system of the distance measuring device 13, for example, when the object 20 is at the lower limit of the distance measuring range set in the distance measuring device 13, The optical system is adjusted so that the spot image 434 is positioned inside the light receiving region 431 from the lower end of the light receiving region 431 and the light receiving element 430 detects the light intensity of the signal light.

Note that the light beam C ₂ incident on the light receiving element 430 in the distance measuring device 13 due to diffusion on the propagation path is a spot image formed by the straight light beam C ₂ as indicated by the

diffusion lines

433 and 435 in the drawing. It has a larger diameter than 432,434. Thus, even chief ray incident on the light receiving portion 400 is deviated from the light receiving region 431, a portion of light ray C ₁ derived from the signal light can range finding if within the range of viewing angle of the light receiving portion 400 State is maintained. Therefore, when the distance measuring device 13 is calibrated, the optical system may be adjusted in anticipation of a wider range than the range in which the

spot images

432 and 434 are formed in the light receiving region 431.

Needless to say, the shape of the light receiving region 431 of the light receiving element 430 is not limited to a rectangle. Rather, considering that the correction range by the calibration unit 600 is defined as the shape of the light receiving region 431, the shape of the light receiving region 431 may be a circle having a uniform interval from the center to the edge. Thereby, the correction range by the calibration part 600 can be made equal in all directions. Further, an optical member having a positive refractive index may be provided in front of the light receiving element 430 so that the signal light ray C ₂ is condensed on the light receiving element 430.

The manufactured distance measuring device 13 calibrates the optical system so that the signal light reflected by the object to be measured is received by the light receiving element 430 before shipment. Thereby, the distance measuring device 13 ensures the distance measurement accuracy and the distance measurement range as specified. However, even with the calibrated distance measuring device 13, the distance measuring accuracy and the distance measuring range may change due to a cause such as a change in diameter and a shock received from the outside.

The distance measuring accuracy of the distance measuring device 13 can be calibrated by measuring the object set at a known distance and comparing the obtained distance value with the known distance. When the distance measuring range of the distance measuring device 13 is calibrated, the calibration unit 600 provided in the distance measuring device 13 is used.

FIG. 22 is a schematic diagram for explaining the operation of the correction member 310 driven by the drive unit 320 in the distance measuring device 13. When driven by the drive unit 320, the correction member 310 shifts in a direction substantially orthogonal to the propagation direction of the light beam B ₂ of the signal light generated by the light emitting unit 210. Thereby, the propagation direction of the light rays A ₂ and B ₂ transmitted through the correction member 310 changes.

In the illustrated example, the correction member 310 has a negative refractive power. Therefore, as shown by the solid line in the figure, the correction member 310 may have shifted downward in the figure, the propagation optical path of the light beam B ₂ is then shifted upward in the drawing, are projected to the outside as light B ₃ shown by a solid line . In addition, after the light beam A ₁ incident on the objective optical system 220 from above in the drawing passes through the correction member 310, it becomes a light beam A ₂ that propagates horizontally in the distance measuring device 13 in the drawing. When the correction member 310 has a positive refractive index, the deviation direction of the light propagation path with respect to the lens movement direction is opposite to that when the lens is negative.

Further, as shown by a dotted line in the figure, the correction member 310 may have shifted upward in the drawing, the propagation optical path of the light beam B ₂ is then displaced downward in the figure is projected to the outside as light B ₃ shown by a dotted line . In addition, after the light ray A ₁ incident on the objective optical system 220 from below in the figure passes through the correction member 310, it becomes a light ray A ₂ that propagates horizontally in the distance measuring device 13 in the figure.

FIG. 23 is a schematic diagram showing a state in which a calibration operation for matching the distance measurement range of the distance measurement device 13 with a preset range is executed. In the calibration of the distance measurement range, the signal light reflected by the standard object 22 arranged at a known relative position with respect to the distance measurement device 13 is received by the light receiving element 430 over the entire range of the distance measurement range. Adjust the optical system.

The relative positions of the distance measuring device 13 and the standard object 22, in addition to the standard distance D _R in which predetermined the height is aligned with the distance measuring device 13 and the standard object 22, the distance measuring device 13 This includes conditions such that the orientation is perpendicular to the standard object 22. In addition, it is desirable that the distance measuring device 13 that performs the calibration operation is fixed horizontally and the standard object 22 is fixed vertically.

It should be noted that it is desirable to use a standard object 22 that has contrast in reflectance with respect to the signal light of the distance measuring device 13. That is, the standard object 22 having a surface having a remarkably high reflectance or a remarkably low reflectance as compared with the surrounding environment can be used.

Alternatively, the standard object 22 having both a region with a high reflectance and a region with a low reflectance may be used. Further, when the standard object 22 is used, since the distance measuring device 13 is collimated with respect to the standard object 22, it is preferable that the standard object has a high contrast even in the visible light band.

FIG. 24 is a schematic diagram for explaining a scanning pattern related to the distance measuring range of the distance measuring device 13. When calibrating the distance measurement range of the distance measuring device 13 installed as described above, first, the reticle of the collimation unit 100 is visually aligned with the standard object 22. Next, the calibration control unit 630 continuously operates the drive unit 320 to shift the correction member 310.

Thereby, as shown in the drawing, the entire visual field of the collimation unit 100 in the distance measuring device 13 is scanned with the signal light. Therefore, the signal light is projected onto both the area where the standard object 22 exists and the area where the standard object 22 does not exist. A high reflectivity region 24 having a high reflectivity for signal light is provided at the center of the standard object 22 used for the calibration operation.

FIG. 25 is a graph showing the received light intensity of the signal light detected by the light receiving element 430 in the calibration operation. In the example shown in FIG. 24, the visual field of the collimation unit 100 is scanned by the signal light reciprocating 3.5 times.

In the calibration operation, the signal light is not detected by the light receiving element 430 during a period when the signal light is not projected onto the standard object 22. In addition, when the scanned signal light is projected onto the standard object 22, the received light intensity at the light receiving element 430 of the signal light reflected by the standard object is measured.

Further, when the scanned signal light is projected onto the high reflectance region 24 of the standard object 22, a stronger light intensity is measured by the light receiving element 430. Thereby, the intensity measuring unit 640 measures the signal intensity exceeding the predetermined threshold value P _th .

In other words, the intensity measurement unit 640 reflects the received light intensity when the signal light is reflected in the high reflectance region 24 of the standard object 22 and the signal light in a region other than the high reflectance region 24 of the standard object 22. The threshold value P _th is set between the received light intensity and the received light intensity. Thereby, the calibration control unit 630 detects that the signal light has been applied to the center of the standard object 22.

FIG. 26 is a flowchart showing the procedure of the distance measurement range calibration operation by the calibration unit 600 as described above. As shown in the figure, when the calibration operation is started, the calibration control unit 630 first issues a command to the driving unit 320 to scan the visual field of the collimation unit 100 with the signal light (step S201).

Next, the calibration control unit 630 causes the intensity measurement unit 640 to continuously measure the received light intensity of the signal light by the light receiving element 430 (step S202). Furthermore, the calibration control unit 630 monitors whether or not the light intensity of the signal light measured by the intensity measurement unit 640 exceeds a predetermined threshold value P _th (step S203).

Here, when the light reception intensity of the light receiving element 430 does not exceed the threshold value _Pth (step S203: NO), the calibration control unit 630 continues to monitor the measurement value by the intensity measurement unit 640. On the other hand, when the received light intensity of the light receiving element 430 exceeds the threshold value _Pth (step S203: YES), the calibration control unit 630 calculates the position of the correction member 310 at that time (step S204).

The calibration control unit 630 calculates the position of the correction member 310 from the drive amount of the drive unit 320 based on the command generated by the calibration control unit 630 itself. The calibration control unit 630 stores the position of the correction member 310 thus calculated in the storage unit 650 as the calibrated initial position of the correction member 310 (step S205).

The calibrated initial position is held in the storage unit 650 by a series of operations as described above. Therefore, when the distance measuring device 13 starts the distance measuring operation, first, the driving unit 320 is operated to move the correction member 310 to the initial position. Thereby, the distance measuring device 13 can execute the distance measuring operation in a calibrated state.

When the calibration value is acquired as described above, the calibration control unit 630 further continues scanning with the signal light, and changes to a state where the light intensity measured by the intensity measurement unit 640 does not exceed the threshold value P _th again. You may confirm that you did. Furthermore, the calibration control unit 630 may repeat the scanning of the signal light and the calculation of the calibration position until receiving a stop instruction from the outside. On the other hand, the calibration control unit 630 may voluntarily end the calibration operation when the calibration value is acquired.

As described above, the distance measuring device 13 includes the calibration unit 600 that performs the calibration operation by moving the correction member 310, so that not only calibration before shipment is facilitated, but also calibration is easily performed after shipment. it can. Therefore, for example, when the power of the distance measuring device 11 is turned on, a calibration operation may be executed or recommended as a part of initialization. The timing for executing the calibration operation may depend on an external instruction from the user or the like. Further, the calibration control unit 630 may notify the user at predetermined time intervals.

FIG. 27 is a schematic diagram illustrating scanning of signal light by the calibration unit 600. In the example illustrated in FIG. 24, the position of the correction member 310 when the signal light is projected onto the high reflectance region 24 of the standard object 22 by reciprocating scanning of the signal light within the field of view of the collimation unit 100 is determined. Detected.

However, the scanning pattern of the signal light in the calibration operation is not limited to the reciprocating movement. For example, as shown in FIG. 27, the high reflectance region 24 may be searched by scanning with a spiral scanning pattern. Furthermore, when the distance measuring device 13 has already been calibrated, scanning with the spiral scanning pattern may be started from the calibration position specified by the last calibration operation.

FIG. 28 is a graph showing a change in received light intensity in the light receiving element 430 detected when the signal light is scanned by the above scanning pattern. As shown in the drawing, the high reflectance region 24 is detected early by scanning in a spiral shape from the already specified calibration position, and the time required for the calibration operation can be shortened.

FIG. 29 is a schematic diagram of an auxiliary member 700 that can be used when causing the distance measuring device 13 to perform distance measurement accuracy and a distance measurement range calibration operation. The auxiliary member 700 has an auxiliary optical system 710 and a standard object 22.

The auxiliary optical system 710 can make the standard object 22 observed through the objective optical system 220 appear to be located farther than the actual position. Therefore, by using the auxiliary member 700, the calibration operation can be executed without installing the standard object 22 in the distance measuring range of the distance measuring device 13 ranging from several hundred meters to 1 kilometer or more.

FIG. 30 is a schematic diagram of the reticle plate 120. The illustrated reticle plate 120 is formed of a transmissive liquid crystal display panel having a plurality of pixels. The reticle plate 120 can selectively display any one of the plurality of reticles 122 and 124 (122) having different positions by displaying a part of the plurality of pixels.

Thereby, it is possible to correct a deviation between the projection position of the signal light by the light transmission unit 200 and the position of the reticle 122 in the field of view of the collimation unit 100. In addition, when either the calibration unit 600 or the correction unit 300 cannot calibrate or correct the optical system within the movement range of the correction member 310, the reticle 122 can be moved to compensate. It should be noted that the light emitting unit 210 may also be moved to further expand the optical adjustment range of the distance measuring device 13.

As described above, when the reticle plate 120 has the movable reticle 122, the projection position of the signal light and the reticle 122 can be matched without adjusting the optical system of the distance measuring device 13. Therefore, it is possible to provide a method for easily calibrating the position of the reticle 122 before and after shipment of the distance measuring device 13.

For example, when the distance measuring device 13 is not shipped from the factory, the position of the reticle 122 can be adjusted using a calibration facility including a light receiving element. That is, the signal light emitted from the light transmitting unit 200 is received by the light receiving element through the collimating optical system, and the reticle 122 is made to coincide with the position of the light receiving unit within the field of view of the collimating unit 100. Thereby, the reticle 122 can be matched with the projection position of the signal light.

If calibration equipment outside the distance measuring device 13 cannot be used, first, signal light is projected while the correction member 310 is displaced in the light transmitting unit 200. Next, the position of the correction member 310 when the signal light is received at the center of the light receiving region 431 in the light receiving element 430 is specified. Based on the displacement amount of the correction member 310 thus obtained, the deviation amount between the signal light projection position and the reticle 122 can be calculated. Therefore, by moving the position of the reticle 122 so as to cancel out the displacement amount of the correction member 310, the reticle 122 can be made to coincide with the projection position of the signal light.

Of course, the shape of the reticle 122 formed on the reticle plate 120 is not limited to that shown in the figure, and the shape of the reticle 122 can be various shapes such as a cross, a rectangle, and a scale. When a member having a dot matrix display function such as a liquid crystal display plate is used as the reticle plate 120, the shape, size, etc. may be changed in addition to the position of the reticle 122.

In the distance measuring device 13, the case where the calibration unit 600 is formed using the correction member 310 and the drive unit 320 provided on the light transmission unit 200 side has been described as an example. However, as shown in FIG. 16, the calibration unit 600 can also be formed in the distance measuring device 11 in which the

correction members

310 and 312 and the driving

units

320 and 322 are provided in both the light transmitting unit 200 and the light receiving unit 400. In this case, the calibration operation may be executed on both the light transmitting unit 200 side and the light receiving unit 400 side, or the calibration operation may be executed on either side. Further, as shown in FIG. 18, the calibration unit 600 can be formed also in the distance measuring device 12 provided with the correction member 312 and the drive unit 322 only in the light receiving unit 400.

As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

The execution order of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior”. It should be noted that they can be implemented in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for the sake of convenience, it means that it is essential to carry out in this order. is not.

10, 11, 12, 13 Distance measuring device, 20 object, 22 standard object, 24 high reflectivity region, 100 collimation part, 110 eyepiece optical system, 120 reticle plate, 122, 124 reticle, 130 erecting prism, 132, dichroic reflection surface, 134, 136 total reflection surface, 200 light transmission unit, 210 light emission unit, 220, 410 objective optical system, 300, 301, 302 correction unit, 310, 312 correction member, 320, 322 drive unit, 330 correction Control unit, 340 shake detection unit, 400 light receiving unit, 420 band transmission filter, 430 light receiving element, 431 light receiving region, 432, 434, 436 spot image, 433, 435 diffusion region, 500 distance measuring unit, 510 clock unit, 520 measurement Distance control unit, 530 display unit, 600 calibration unit, 630 Positive control unit, 640 intensity measuring unit, 650 storage unit, 700 an auxiliary member, 710 an auxiliary optical system

Claims

A light transmitting section for transmitting signal light from the light source toward the object;
A light receiving unit that has a light receiving element and receives the signal light from the object on an optical axis different from that of the light transmitting unit;
A distance measuring unit for measuring a distance to the object based on a propagation time of the signal light from light transmission to light reception;
In the state where either one of the optical path from the light transmitting unit and the light receiving unit and the optical path from the object to the light receiving element is fixed, the optical path is set in the other of the light transmitting unit and the light receiving unit. A distance measuring device comprising: a correction unit that is displaced to correct the optical path of the signal light.
2. The distance measuring device according to claim 1, wherein the correction unit displaces the optical path so as to receive the signal light within a light receiving range of the light receiving element.
When the light receiving element is located in the center of the range in which the optical path is displaced, the signal light is intersected with a plane including the optical axis of the light transmitting unit and the optical axis of the light receiving unit in the light receiving range, or The distance measuring device according to claim 1, wherein light is received in the vicinity thereof.
The distance measuring device according to any one of claims 1 to 3, further comprising a notification unit that notifies the fact that the optical path cannot be corrected even if the optical path is displaced to a limit.
The distance measuring device according to claim 4, wherein the notifying unit notifies that the displaced optical path has approached a limit of a displacement range.
The correction by the displacement of the optical path is stopped during a period in which the amplitude of the displacement of the optical path in at least one of the light transmitting unit and the light receiving unit exceeds a range that can be corrected by the displacement of the optical path. The distance measuring device according to any one of the above.
The distance measuring device according to any one of claims 1 to 6, wherein the correction unit includes a regulation unit that mechanically regulates a range in which the optical path is displaced.
The distance measuring device according to any one of claims 1 to 7, wherein the correction unit corrects a parallax between the light transmission unit and the light reception unit by displacing the optical path.
The distance measuring device according to any one of claims 1 to 8, wherein the correction unit corrects image blurring in at least one of the light transmission unit and the light reception unit.
The measurement unit according to claim 8 or 9, wherein the correction unit displaces the optical path more greatly when a blur amplitude in at least one of the light transmission unit and the light reception unit exceeds a predetermined threshold. Distance device.
The distance measuring device according to any one of claims 8 to 10, wherein the correction unit displaces the optical path more greatly when a distance to the object is closer than a predetermined threshold value.
The distance measuring device according to any one of claims 1 to 11, wherein the correction unit displaces the optical path based on a received light intensity of the signal light reflected by the object in the light receiving unit. .
13. The distance measuring device according to claim 12, wherein the correction unit displaces a correction member to displace the optical path in a direction in which the intensity of the signal light received by the light receiving element is higher.
The correction unit calibrates the initial position of the optical axis based on the received light intensity of the signal light reflected by a known standard object in the light receiving unit, and shifts from the calibrated initial position to change the initial position. The distance measuring device according to claim 12 or 13, wherein the optical path is corrected.
15. The distance measuring device according to claim 14, wherein the correction unit scans the signal light starting from an initial position calibrated last.
16. The distance measuring device according to claim 14, wherein the correction unit calibrates and updates the initial position of the optical axis when receiving an instruction from the outside.
Comprising a collimation unit for visualizing the object and collimating the light transmission unit;
The distance measuring device according to any one of claims 12 to 16, wherein the correction unit calibrates a position of an optical path with respect to a reticle to be matched with the object in the collimation unit.
18. The distance measuring device according to claim 17, wherein the reticle is formed by a display image selected from a plurality of images and displayed on a display unit.
A light transmitting unit that transmits signal light from the light source toward the object; a light receiving unit that includes a light receiving element; and that receives the signal light from the object on a different optical axis from the light transmitting unit; A distance measuring unit that measures a distance to the object based on a propagation time from light transmission to light reception of the signal light, and one optical axis of the light transmission unit and the light reception unit is fixed. A calibration method for calibrating a distance measuring device including a correction unit that corrects an optical path of the signal light by displacing an optical path in the other of the optical unit and the light receiving unit,
Measuring the received light intensity at the light receiving portion of the signal light reflected by a known standard object while displacing the optical path;
Determining the initial position of the optical path by displacing the optical path.