JP3154047B2 - Surveying instrument with AF function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surveying instrument having an AF function of a collimating telescope, and more particularly to an arrangement structure of an AF branch optical system.

[0002]

2. Description of the Related Art A surveying instrument such as an optical distance meter or a total station is provided with a collimating telescope for collimating a target (target). The telescope is aimed at a target point, and the focus adjustment knob is manually rotated with respect to the target point to perform focus adjustment on the target point. However, manual focus adjustment has problems such as being unable to concentrate on collimation and having a long time for focus adjustment operation.

Therefore, a surveying instrument having a collimating telescope having an automatic focusing function (AF function) has recently been developed. This AF function guides the object light transmitted through the focusing lens of the collimating telescope to a conjugate plane conjugate with the focal plane,
The focus state on the conjugate plane is detected, the defocus amount of the focus lens is calculated, and the focus lens is moved to the focus position based on the defocus amount. The principle of this AF itself is well known, and A
Widely used in F single-lens reflex cameras.

In a surveying instrument having this AF function, in order to detect a focus state, an optical path for focus detection must be branched from a collimating optical system, and an AF sensor must be provided in the branched optical system. For this reason, a conventional surveying instrument having an AF function is inevitably increased in size.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a surveying instrument having an AF function of a collimating telescope, which can avoid an increase in size.

[0006]

SUMMARY OF THE INVENTION The present invention has been completed as a result of research on the construction of a branch optical system for AF without increasing the size of the surveying instrument as a whole.

A surveying instrument having an AF function according to the present invention
In order from the target object side, an objective lens, a focusing lens system for focus adjustment, a porro prism constituting an erecting optical system, a collimating telescope having a reticle and an eyepiece; and one of the reflecting surfaces of the porro prism A light splitting element adhered to the semi-transmitting face as a semi-transmitting face; and a forward reflection for guiding the split light beam split by the light splitting element substantially parallel to the optical axis of the collimating telescope and forward from the Porro prism. An AF sensor for detecting a focus state in a conjugate plane conjugate with the reticle placed on an optical path behind the front reflection element; and driving the focus lens system according to an output of the AF sensor. A focus lens driving device; wherein the optical axis of the objective lens and the optical axis of the eyepiece are located in the same horizontal plane, and the porro prism is provided with an incident surface orthogonal to the optical axis of the objective lens; First right-angled prism having a reflecting surface that forms a 45 degrees with respect to the optical axis of the objective lens for reflecting an incident beam of light from the surface downward, an exit surface perpendicular to the incident surface;
An entrance / exit surface parallel to the exit surface of the first right-angle prism, a second reflection surface for reflecting a light beam incident from the entrance / exit surface at right angles in a plane orthogonal to the objective lens optical axis, and a second reflection surface A second prism having a third reflecting surface orthogonal to the second reflecting surface, which reflects the light beam reflected by the surface at right angles in a plane orthogonal to the optical axis of the objective lens, and then emits the light from the entrance / exit surface; An entrance surface parallel to the entrance / exit surface of the second prism; a fourth reflection surface for reflecting a light beam incident from the entrance surface so as to coincide with an optical axis of an eyepiece parallel to the optical axis of the objective lens; And a third right-angle prism having an exit surface orthogonal to the light-dividing element;
The AF sensor is attached to the second or fourth reflecting surface of the Porro prism, and the AF sensor is an AF sensor that integrates the AF sensor and a reflecting mirror that reflects an incident light beam and gives the AF beam to the AF sensor. It is characterized by being provided in the unit.

The surveying instrument of the present invention further includes a distance measuring means for measuring the distance to the target; and a distance for driving the focus lens of the collimating telescope based on the distance to the target measured by the distance measuring means. Means for selectively using a priority focusing function; a distance priority focusing function; and an AF function based on an output of an AF sensor.

[0009]

[0010]

1 and 2 show a surveying instrument capable of moving a focus lens to a focus position by an AF function and a focus position based on distance information measured by a distance measuring device. It is an embodiment to which the invention is applied. The present applicant has separately filed a patent application for this surveying instrument (Japanese Patent Application No. 8-258481). First, the surveying instrument will be described with reference to FIG.

The surveying instrument (total station or lightwave rangefinder) shown in FIG. 1 has a lightwave rangefinder and a collimating telescope. The lightwave range finder includes a light transmitting unit 11 for transmitting distance measuring light, a dichroic prism 13 for reflecting the distance measuring light, a light projecting lens for emitting the distance measuring light to a target, and a target (for example, a corner cube) O. The objective lens 15 also functions as a light receiving lens for receiving the distance measuring light reflected by the light source, the mirror 17 that reflects the distance measuring light incident from the objective lens 15 and reflected by the dichroic prism 13, and the light reflected by the mirror 17 Light receiving unit 19 for receiving long-distance light, and light transmitting unit 11
And a distance measurement calculation unit 21 for controlling the light receiving unit 19 and detecting a distance measurement value. The light transmitting unit 11 includes a light emitting diode or a laser diode as a distance measuring beam light emitting unit, and a light transmitting unit including an optical system incorporating these elements. Dichroic prism 13
Is formed so that the distance measurement light is reflected, but natural light (visible light) is transmitted. Therefore, as a distance measuring light,
Light outside the visible light region, for example, in the infrared light region is used. In addition, besides placing the above-mentioned corner cube O and mirrors on the target, non-prism (non-corner cube)
The lightwave rangefinder utilizes the reflection of the surface of the target object.

The distance calculating section 21 is based on the distance measuring light (internal reference light) emitted from the light transmitting section 11 and the distance measuring light received by the light receiving section 19 and is provided with a known method such as a phase difference measuring method or an optical radar method. The distance to the target is calculated by the algorithm described in (1). Although not shown, the calculated distance is displayed on a display panel or the like. The focus lens position calculation unit 23 calculates a movement position of the focus lens 31 necessary for focusing on a target located at the distance based on the distance calculated by the distance measurement calculation unit 21.

[0013] On the other hand, the collimating telescope, in order from the target side,
An objective lens 15, a dichroic prism 13, a focus lens 31, an erect prism (porro prism) 33,
A light splitting prism (light beam splitting system) 34, a focusing plate 35, and an eyepiece 37 are provided. These collimating telescope and the lightwave distance measuring unit are not shown, but are integrally assembled to a surveying instrument main body. This main body is mounted on a base so that the azimuth and the elevation angle can be adjusted with the vertical axis and the horizontal axis as axes. I have.

The target light beam (visible light) incident from the objective lens 15 passes through the dichroic prism 13 and
Through the focus lens 31 and the erecting prism 33, an image is formed on the focusing screen 35 or near the front and rear thereof as an erect real image. The operator observes this image through the eyepiece 37 in an enlarged manner. The focusing screen 35 is provided with a distance measurement mark as a target for irradiating the distance measurement light and other crosshairs necessary for the surveying. The operator can see the image of the target object overlapping the distance measurement mark or the like. And adjust the azimuth and elevation angle of the collimating telescope so that the target enters the distance measurement mark, that is, the distance measuring light hits the collimation object.

An AF sensor (focus detection sensor) 41 for detecting a focus state (defocus amount) on a conjugate plane 35C conjugate with the focusing plate 35 is provided on the optical path branched by the light splitting prism 34. AF sensor 41
The light receiving signal received by the line sensor placed near the conjugate plane 35C is output to the focus state (defocus amount) calculation unit 42, and various specific configurations are known. FIG.
Shows an example of the principle thereof. A condenser lens 41a and a pair of separator lenses 41 are provided behind the conjugate plane 35C.
b and a pair of line sensors 41c such as CCDs located behind the respective separator lenses 41b.

The incident position of the object image on the pair of line sensors 41c is such that when the image of the target is accurately formed on the conjugate plane 35C (in focus), it is formed ahead of the conjugate plane 35C. Respectively (front focus) and when imaging behind the conjugate plane 35C (rear focus), respectively.
The amount of deviation from the in-focus position is also determined by the pair of line sensors 4.
The determination can be made based on the image formation position of the object image on 1c. Focus state calculation unit 4 receiving outputs from a pair of line sensors 41c
2 amplifies this output by a preamplifier (not shown), and then calculates by an arithmetic circuit (not shown) to detect in-focus, out-of-focus, front focus, and rear focus, and to detect on the conjugate plane 35C. And the amount of movement of the focus lens 31 necessary for focusing are detected.

Either of the data of the movement amount (movement position) of the focus lens 31 by the focus lens position calculation unit 23 and the focus state calculation unit 42 is transferred to the focus lens position control unit 45 via a focusing mode selection switch 45. 4
4 given. The focus lens position control unit 44
Focus lens position calculator 23 and focus state calculator 42
Based on one of the outputs and the lens position data of the focus lens 31 detected by the focus lens position detecting device 29, the focus lens driving device 27 using a motor or the like as a driving source is operated to operate the focus lens 3.
1 is moved to the in-focus position.

Therefore, the movement control of the focus lens 31 is performed in the automatic focusing mode when the focus state (defocus amount) calculation section 42 is connected to the focus lens position control section 44 by the focusing mode selection switch 45. In a state in which the focus lens position calculation unit 23 is connected to the focus lens position control unit 44, the focusing is performed in the distance priority focusing mode. Further, the focus lens driving device 27 is provided by the manual focusing device 28.
To move the focus lens 31 to an arbitrary position. Furthermore, a specific distance can be input by the focusing distance input means 30, and the focus lens 31 can be moved via the focus lens position control unit 44 so as to focus on the input distance. In addition,
Input the position information (coordinate values) where the surveying instrument is installed and the target position information (coordinate values), calculate the distance to the target from these coordinate values, and focus on that distance. The focus lens 31 can also be moved via the focus lens position controller 44. Focusing distance input means 30
For example, information read from a keyboard, various memories, or communication information can be used.

The focus mode can be changed by the operator manually switching the focus mode selection switch 45. For example, the focus mode can be changed in the following mode. Before the light receiving unit 19 of the lightwave distance measuring device receives the reflected light from the target, the automatic focusing mode is set. When the light receiving detector 47 detects that the light receiving unit 19 has received the reflected light, the distance priority is set. Switch to focus mode. The fact that the light receiving unit 19 has received the reflected light means that the collimating telescope has correctly collimated the target, so that if the focusing is performed at the distance of the target, the surveying instrument and the target are thereafter During this time, even if an object that becomes noise enters or exits, it is possible to accurately focus on the target. When the surveying instrument is a total station having an angle measurement function and a memory function of the angle measurement information, the mode is switched from the automatic focusing mode to the distance priority focusing mode at a specific angle measurement position. For example, in the paired observation used in reference point surveying or the like, the same target (plural) is collimated and measured a plurality of times, so it is necessary to focus each time. In such a survey, the angle information and the position information at the time of first focusing on each target are stored in the memory unit 46, and when a specific angle measurement position is reached, the distance priority focusing mode is set. The target can be focused on the basis of the distance data to the target.

During the surveying operation, when the light receiving section 19 changes from a state in which it receives the distance measurement reflected light to a state in which it does not receive the distance measurement reflected light, it is assumed that a target (for example, a corner cube O) is being moved. Is done. At this time, the position of the next target often does not largely change from the state where the distance measurement reflected light is received. Therefore, if the focus adjustment range of the automatic focusing function is limited to a narrow range including the distance information immediately before the reflected light is no longer received, based on the distance information immediately before the reflected light is no longer received, the next automatic focusing can be performed. Scorching can be performed more quickly.

The relationship between the distance measurement distance and the lens position of the focus lens 31 that focuses on the target at the distance measurement distance (an image of the target at that distance is formed on the focusing screen 35) is, for example, as follows. Set as follows. These relationships are obtained in advance by calculation from the design values of the optical system or by actual measurement of the target, and these relationships are divided into a number of zones, converted into table data, and stored in a memory means such as a ROM. And
The lens position is obtained by referring to the table data with the distance data calculated by the distance measurement calculation unit 21. In addition, the relationship between the distance measurement distance and the lens position of the focus lens 31 that focuses on the target at that distance is formed into an arithmetic expression, and the arithmetic expression is stored in a ROM or the like. It can also be obtained by calculation.

A focus lens position detecting device 29 for detecting the position of the focus lens 31 includes a code plate extending along the moving direction of the focus lens 31 and an absolute position detecting device for reading a position code formed on the code plate by reading means. The relative position detecting means for detecting the amount of movement of the focus lens 31 from the reference position by counting the number of rotations of the motor of the focus lens driving device 27 can be detected. Further, a configuration is also possible in which the position of the focus lens 31 is roughly detected by the absolute position detection unit and is precisely detected by the relative position detection unit.

The present invention is applied to, for example, a surveying instrument having the above-described AF function. FIG. 3 shows a more specific configuration of a surveying instrument (total station) to which the present invention is applied. FIG. 3 does not show a branch optical system for AF. On the optical axis O1 of the collimating telescope, an objective eyepiece 15, a dichroic prism 13, a focus lens 31, and a Porro prism 33 are provided.
The optical axis O1 of the objective eyepiece 15 and the optical axis O2 of the eyepiece 37 are located in the same horizontal plane. The Porro prism 33 has an optical axis O as shown in detail in FIGS.
A first right-angle prism having an incident surface 33a orthogonal to the first surface 1 and a first reflecting surface 33b that bends a light beam incident from the incident surface 33a downward. A second right-angle prism having a second reflecting surface 33c that reflects in a direction perpendicular to the second reflecting surface, and a third reflecting surface 33d that reflects the light flux reflected by the second reflecting surface 33c upward, and the third reflecting surface 33d. And a third right-angle prism having an exit surface 33f orthogonal to the optical axis O2 and a fourth reflection surface 33e for reflecting the light beam reflected by the optical axis onto an optical axis O2 parallel to the optical axis O1. The eyepiece 37 is arranged on the optical axis O2.

The above elements and each element described in FIG.
The housing 51 is housed in the housing 51.
3 through a horizontal rotation about a vertical rotation axis X1 orthogonal to the optical axis O1, and the intersection of the optical axis O1 and the vertical rotation axis X1.
Can be rotated up and down around a horizontal turning axis X2 perpendicular to the plane of the drawing.

The branch optical system for AF according to the present invention comprises four reflecting surfaces 33b, 33c, 33d of a Porro prism 33,
And 33e, the second reflecting surface 33c or the fourth reflecting surface 33e is a semi-transmissive surface, a light splitting prism (light splitting element) is attached to the semi-transmissive surface, and the light is split by the light splitting element. The split light beam is guided by a front reflection element parallel to the optical axis O1 and forward of the Porro prism 33, and is formed on an optical path behind the front reflection element with an AF sensor. As described above, the branch optical path for AF divided by the Porro prism 33 is guided forward of the Porro prism 33, so that the space in the housing 51 can be effectively used and the housing 51 does not become large. .

FIGS. 8 and 9 show a first embodiment. In this embodiment, the second reflection surface 33c of the Porro prism 33
Is a semi-transmissive surface, and a light splitting prism 52 is adhered to the second reflecting surface 33c. The split optical path O3 split by the light splitting prism 52 is orthogonal to the optical axis O1, and a front reflective prism 53 as a front reflective element is disposed on the split optical path O3. The front reflecting prism 53 bends the divided optical path O3 forward at a right angle, a first reflecting surface (front reflecting surface) 53a, and the first reflecting surface 53a bends the forward optical path O4 further downward at a right angle. It has one reflecting surface 53a and a second reflecting surface 53b that is parallel. The focusing screen 35C is located on the optical path O5 reflected by the second reflecting surface 53b, and the AF sensor unit 60 is located behind the focusing screen 35C. AF sensor unit 60
Are the reflection mirror 61 and the AF sensor 41 described with reference to FIG.
The AF sensor 41 detects the focus state of the reticle 35C.

FIGS. 10 and 11 show a second embodiment. In this embodiment, a light splitting prism 52 and a front reflection prism 53 which are separately installed in the first embodiment are bonded, and other configurations are the same as the first embodiment.

FIGS. 12 and 13 show a third embodiment. In this embodiment, the direction of the AF sensor unit 60 of the second embodiment is changed. That is, the AF sensor unit 60 includes the reflection mirror 61 and the reflection mirror 6.
Even if it is rotated about the point of intersection with the optical axis incident on the optical axis 1, it is optically equivalent. In the first and second embodiments, the optical path from the reflection mirror 61 to the AF sensor 41 is the optical axis O1.
In the third embodiment, the optical path from the reflection mirror 61 to the AF sensor 41 is parallel to the optical axes O1 and O2.
And in a direction (lateral direction) perpendicular to the direction.

FIGS. 14 to 16 show a fourth embodiment. This embodiment corresponds to an embodiment in which the front reflection prism 54 is used instead of the front reflection prism 53 of the second embodiment, and the direction of the AF sensor unit 60 is changed.
The front reflection prism 54 includes a front reflection surface 54a similar to the first reflection surface 53a of the front reflection prism 53, and an emission surface 54b orthogonal to the front optical path O4 reflected by the front reflection surface 54a. The reflection mirror 61 of the AF sensor unit 60 is placed directly on the front optical path O4. The direction of the AF sensor unit 60 can be freely set as described above.

FIGS. 17 to 19 show a fifth embodiment. In this embodiment, the light dividing prism 56 is adhered to the fourth reflection surface 33e of the Porro prism 33 as a semi-transmission surface. The split optical path O6 split by the light splitting prism 56 is orthogonal to the optical axis O1.
Above, the AF sensor unit 60 is arranged. In this embodiment, the reflection mirror 6 of the AF sensor unit 60 is used.
The direction of the AF sensor unit 60 is determined so that the optical path O7 from 1 to the AF sensor 41 forms a forward reflection optical path parallel to the optical axis O1.

The light splitting prisms 52 and 56 are theoretically
Any one of the first reflecting surface 33b to the fourth reflecting surface 33e can be used as a semi-transmissive surface and adhered to this. However, as in each of the above embodiments, by attaching the light splitting prisms 52 and 56 to the second reflecting surface 33c or the fourth reflecting surface 33e of the Porro prism 33, the AF split optical path can be simplified. It can be configured in a configuration.

[0032]

According to the present invention, when incorporating the AF function into a surveying instrument, a small branching optical system for AF can be constructed by using a porro prism as an erecting optical system.
There is no increase in the size of the surveying instrument.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of a surveying instrument to which the present invention is applied.

FIG. 2 is a diagram illustrating a specific example of an AF sensor unit in FIG. 1;

FIG. 3 is a side sectional view showing a specific example of a surveying instrument to which the present invention is applied.

FIG. 4 is a perspective view of a Porro prism of the surveying instrument of FIG. 3;

FIG. 5 is a front view of the same.

FIG. 6 is a plan view of the same.

FIG. 7 is a side view of the same.

FIG. 8 is a front view showing a first embodiment of an AF branch optical system according to the present invention.

FIG. 9 is a side view of the same.

FIG. 10 is a front view showing a second embodiment of an AF branch optical system according to the present invention.

FIG. 11 is a side view of the same.

FIG. 12 is a front view showing a third embodiment of a branching optical system for AF according to the present invention.

FIG. 13 is a side view of the same.

FIG. 14 is a front view showing a fourth embodiment of the branch optical system for AF according to the present invention.

FIG. 15 is a plan view of the same.

FIG. 16 is a side view of the same.

FIG. 17 is a front view showing a fifth embodiment of the AF branch optical system according to the present invention.

FIG. 18 is a plan view of the same.

FIG. 19 is a side view of the same.

[Explanation of symbols]

 15 Objective lens 27 Focus lens driving device 31 Focus lens (focus adjustment optical system) 33 Porro prism 33a Incident surface 33b First reflective surface 33c Second reflective surface 33d Third reflective surface 33e Fourth reflective surface 33f Exit surface 34 Light splitting prism (Beam splitting system) 35 Focusing plate 35C Conjugation surface 37 Eyepiece 41 AF sensor 42 Focusing state (defocus amount) calculation unit 51 Housing 52 56 Light splitting prism 53 54 Forward reflecting prism 60 AF sensor unit 61 Reflecting mirror

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-20468 (JP, A) JP-A-4-20915 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01C 3/00-3/32 G01C 5 / 00,15 / 00 G02B 7/28-7/32 G03B 3/00 G03B 13/18-13/20 G01S 7/48

Claims (4)

(57) [Claims] 1. A collimating telescope comprising an objective lens, a focus lens system for focus adjustment, a Porro prism constituting an erecting optical system, a focusing plate and an eyepiece in order from the target side; A light-splitting element attached to the semi-transmissive surface with any one of the surfaces as a semi-transmissive surface; and a light beam split by the light-splitting element which is substantially parallel to the optical axis of the collimating telescope and a Porro prism. A front reflection element for guiding forward; an AF sensor placed on an optical path behind the front reflection element to detect a focus state on a conjugate plane conjugate with the reticle; A focus lens driving device for driving a focus lens system, wherein the optical axis of the objective lens and the optical axis of the eyepiece lens are in the same horizontal plane.
And the Porro prism has an incident surface perpendicular to the optical axis of the objective lens, and an incident light from the incident surface.
45 with respect to the optical axis of the objective lens that reflects the reflected light beam downward.
反射 and a light exit surface perpendicular to the incident surface.
A first right-angle prism; an input / output surface parallel to the output surface of the first right-angle prism
And the luminous flux incident from the entrance / exit surface is directed to the optical axis of the objective lens.
A second reflecting surface that reflects at right angles in the intersecting plane;
The light beam reflected by the second reflecting surface of
Reflected at right angles in the plane
And a third reflecting surface orthogonal to the second reflecting surface.
Having a second prism; and an entrance / exit surface of the second prism
An incident surface parallel to and a light beam incident from the incident surface are paired.
Reflected according to the eyepiece optical axis parallel to the object lens optical axis
And a light exit surface orthogonal to the light incident surface.
Wherein the light splitting element comprises a second reflecting surface of the Porro prism.
Alternatively, the AF sensor is attached to a fourth reflecting surface , and the AF sensor reflects the incident light beam with the AF sensor.
AF was integrated and a reflecting mirror Ru applied to the AF sensor Te
AF provided in the sensor unit
Surveying instrument with functions. 2. The surveying instrument according to claim 1, wherein said front reflection element has an AF function constituted by a reflection mirror in said AF sensor unit. 3. The surveying instrument according to claim 1, wherein the front reflecting element is constituted by a reflecting element different from a reflecting mirror in the AF sensor unit, and has an AF function. 4. The surveying instrument according to claim 1, further comprising: a distance measuring means for measuring a distance to the target; and a distance measuring means for measuring a distance to the target measured by the distance measuring means. A distance priority focusing function for driving the focus lens of the collimating telescope; and a means for selectively using the distance priority focusing function and the AF function based on the output of the AF sensor. Surveyor.