KR20170036271A

KR20170036271A - Distance measuring apparatus using image division prism

Info

Publication number: KR20170036271A
Application number: KR1020150135228A
Authority: KR
Inventors: 차정원; 이동희
Original assignee: 신한대학교 산학협력단; 주식회사 동인광학
Priority date: 2015-09-24
Filing date: 2015-09-24
Publication date: 2017-04-03

Abstract

The present invention relates to a distance measuring apparatus using an image split prism, comprising: a cylindrical housing with open front and back sides; a doublet object lens composed of two aspheric lenses disposed on a front end portion of the housing to face an object, a distance to which is measured; a display means providing an image of the object lens side to a user; an image split prism disposed between the object lens and the display means to split the image of the object lens side and form an image, and installed to be able to move along an optical axis within the housing to adjust a distance between the split images; and a distance display unit displaying a distance to the object being measured in accordance with the position of the image split prism while a position of the image split prism is adjusted such that the distance between the split images is set at a reference position. As such, it is possible to accurately measure a distance to a flagpole even with an occurrence of vibration such as that from the hands.

Description

[0001] DISTANCE MEASURING APPARATUS USING IMAGE DIVISION PRISM [0002]

The present invention relates to a distance measuring apparatus using a phase-division prism, and more particularly, to a distance measuring apparatus using a phase-division prism capable of measuring a distance to a distance measuring object such as a flagpole or a flag located in a hole with a telescope easily and precisely To a distance measuring instrument.

In general, the competition rules of golf are to check the distance of a hole and then use a golf club corresponding to the distance of the hole to put it in the hole with a minimum number of balls.

At this time, a flagpole having a height of about 2.2 m is set up in the hole so that the golfer can easily check the distance and direction of the hole.

Therefore, a technique of measuring the distance by applying the height of a general flagpole is known from the Utility Model Publication (Publication No. 91-2959: Distance meter for golf flagpole) and will be described as follows.

In the conventional distance measuring device, a fixed upper case and a lower case are fastened and fixed to each other to form a main body, and a fixing part and a supporting part are protruded in a lower case having a projection on one side, and a reflecting mirror and a fixing part A prism mirror was adhered and fixed to one side. A convex mirror was attached to one side support and a transparent glass was closely inserted into one side support. A microfilm with a scale and a reference line was formed on one side of the transparent glass.

However, in the conventional configuration as described above, the flagpole is used by aligning the reference line to measure the distance. Therefore, as the distance increases, the scale becomes denser and there is a problem that the measurement is impossible because the measurement is impossible to make a measurement by comparing with a flagstick which is seen from a long distance.

In order to solve such a problem, a telescope as shown in FIG. 1 and a reticle 40 having a number of the conventional configuration scale and reference lines may be used. However, depending on the enlargement magnification of the telescope, It was difficult to confirm the scale according to the size of the flagpole because it react sensitively.

That is, when the telescope is applied as disclosed in Japanese Laid-Open Patent Application No. 10-2001-0084094, the movement of the image due to the hand tremor or the movement of the body increases in proportion to the magnification of the telescope, It is difficult to confirm the scale by matching the shaky image images, and the accuracy of the distance measurement is lowered, and the use thereof is inconvenient.

On the other hand, the laser distance measuring device which measures the distance by using the reflected light by shooting the laser on the flagpole has the advantage of high accuracy, but it has a disadvantage that the price is high and the distance from the center or the edge of the golfer and the green Distance measuring device using GPS to measure distances has to estimate the exact distance to the flagpole, and it is inconvenient to continuously upgrade.

Therefore, it is necessary to develop a distance measuring instrument which is low in cost and high in accuracy of distance measurement.

Patent Document 1: Korean Patent Laid-Open Nos. 10-2001-0084094, Yoo Sangil (2001.09.06)

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve such conventional problems, and it is an object of the present invention to provide a phase split prism which is separated from an objective lens and an eyepiece lens so as to separate an image into two, And a distance measuring device using the phase splitting prism which can precisely measure the distance to the flagpole even when vibrations such as hand tremors occur by allowing the user to move as if they are stuck together.

Another object of the present invention is to provide a distance measuring apparatus using a phase-division prism capable of applying a high magnification telescope or a zoom lens by improving inconvenience of measurement due to hand tremor.

According to an aspect of the present invention, there is provided a double-type objective lens comprising: a cylindrical housing having front and rear openings; a double-letter-type objective lens composed of two aspherical lenses disposed at the front end of the housing to face the distance measurement object; And an objective lens for focusing the image on the objective lens side so as to adjust an interval between the separated images, A prismatic prism disposed movably in a direction of an optical axis; And a distance display unit for displaying the distance from the object to be measured according to the position of the phase division prism in a state in which the position of the phase division prism is adjusted so that the interval between the separated phases is set at the reference position, This is achieved by a distance measuring device using a split prism.

Here, it is preferable that the objective lens of the double-letter type is composed of a BK series and a SF series.

According to the present invention, by using a phase-division prism disposed between an objective lens and an eyepiece lens, an image is separated into two images, and even if the housing swings due to vibration, the two images are moved together as if they are stuck together, There is provided a distance measuring device using a phase splitting prism capable of precisely measuring the distance to the flagpole even when vibration occurs.

1 is a sectional view showing the construction of a conventional optical golf distance measuring instrument,
FIG. 2 is a sectional view showing a configuration of a distance measuring instrument using a phase-division prism according to a first embodiment of the present invention,
3 to 4 are operational cross-sectional views of a distance measuring instrument using a phase-division prism according to a first embodiment of the present invention,
FIG. 5 is a view showing an observation state of a phase in an operation process of a distance measuring device using a phase-division prism according to a first embodiment of the present invention,
6 to 10 are views showing various modified embodiments of the distance measuring device using the phase-division prism according to the first embodiment of the present invention,
11 is a sectional view showing a configuration of a distance measuring instrument using a phase-division prism according to a second embodiment of the present invention,
12 is a view showing an observation state of an image of a distance measuring instrument using a phase-division prism according to a second embodiment of the present invention,
13 is a view showing a first variation of the distance measuring device using the phase-division prism according to the second embodiment of the present invention.

Prior to the description, components having the same configuration are denoted by the same reference numerals as those in the first embodiment. In other embodiments, configurations different from those of the first embodiment will be described do.

Hereinafter, a distance measuring instrument using a phase-division prism according to a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view of a distance measuring device using a phase-division prism according to a first embodiment of the present invention, and FIGS. 3 and 4 are views showing the operation of a distance measuring device using a phase- Fig.

2, the distance measuring apparatus using the phase-division prism according to the first embodiment of the present invention includes a housing 110, an objective lens 120, a display unit, a phase-division prism 140, a distance display unit 150).

The objective lens 120 includes at least one lens and is disposed at a front end of the housing 110 so as to face the flagpole, and the indicator 110 is disposed at a front end of the housing 110. The indicator 110 may include a cylindrical body having front and rear openings, The eyepiece 130 constituting the means is disposed at the rear end of the housing 110 so as to form an image of the objective lens 120 side on the retina.

The objective lens 120 is of a doublet type composed of two aspherical lenses. The objective lens 120 of the doublet type is composed of a BK series and a SF series.

The phase splitting prism 140 separates the paths of light rays in two directions at the intermediate portion of the light rays originating from the external object and passing through the objective lens to the image forming surface of the objective lens, And an optical medium that provides a means for separating and forming an image.

Here, asymmetric-biprism, which is characterized in that the upper and lower apexes of the biprism are different from each other, the shape of the biprism is defined as four slopes, The prism is formed with at least one of the front and rear surfaces of the prism with a modified-biprism (hereinafter referred to as " modified biprism ") having inclined surfaces A half-prism using only the upper half or lower half of the biprism or modified-biprism, and two inclined surfaces having different slopes on at least one surface thereof are alternately repeated to form a triple- (In this embodiment, the phase-division prism is composed of eight inclined surfaces, for example) A multilayer-biprism or the like. Here, the biprism and the asymmetric biprism may be regarded as being included in a form of a modified-biprism, and the multilayer-biprism may be a multilayer biprism, -biprism, multilayer-asymmetric-biprism, and multilayer-modified-biprism.

In addition, all of the phase-splitting prisms 140 may be replaced with a Fresnel prism type to reduce the thickness of the prism, and any one of ordinary skill in the art will understand that the phase- A phase-splitting prism constituted by adopting a Fresnel prism is also considered to be within the scope of the claims of the present invention.

In this embodiment, a plane is formed on the incident surface so that the phase-splitting prism 140 separates one image provided from the objective lens 120 side into two images P1 and P2, A biprism having inclined planes whose inclination directions are opposite to each other are formed on the upper and lower sides with respect to the center of the optical axis. The phase-splitting prism 140 is installed on the optical path between the objective lens 120 and the eyepiece 130 so as to be movable in the direction of the optical axis.

The distance display unit 150 displays the two images P1 and P2 separated by the phase-division prism 140 by moving the phase-division prism 140 in the direction of the optical axis to a predetermined 'reference position' The position of the phase splitting prism 140 is used in the state where the lower end of the upper image P1 and the upper end of the lower image P2 are in contact with each other, And a distance scale 151 is displayed on the outer side of the housing 110 in the direction of the optical axis.

Although not shown in the drawing, a display window for observing the phase-division prism 140 in the housing 110 may be disposed in parallel with the distance display unit 150 to display the position of the housing 110, The reference indicator line 152 connected to the display unit 140 may be configured to pass through the housing 110 to indicate the distance scale 151 of the distance indicator 150.

Hereinafter, the operation of the first embodiment of the distance measuring instrument using the phase-division prism described above with reference to Figs. 2 to 4 will be described.

FIG. 5A shows the observing state of the eyepiece according to the state of FIG. 2. FIG. 5A shows a state where the lower end of the upper image P1 and the lower image of the lower image P1, The state in which the upper ends of the image P2 are in contact with each other becomes the reference position. In this state, since the position of the phase-division prism 140 is determined as shown in FIG. 2, the observer can view the phase-division prism 140 among the distance-based graduations 151 of the distance indicator 150 provided outside the housing 110, It is possible to measure the distance to the flagpole by reading the scale corresponding to the position of the flag, so that accurate measurement results can be obtained through simple manipulation.

Meanwhile, a process of moving the two phases P1 and P2 to the reference position by adjusting the position of the phase-division prism 140 will be described.

3 shows a state in which the flagpole is located at the same distance as in Fig. 2, and the phase-division prism 140 has moved from the proper position to the objective lens 120 side. In this state, (Refer to FIG. 5 (b)) in which the focal positions formed by the two images P1 and P2 separated by the first and second lens groups 140 and 140 are separated from each other. 5 (b), when the observer observes the flagpole through the housing 110 and the two images P1 and P2 separated by the phase prism 140 are observed as shown in FIG. 5 (b) The prism 140 may be moved in a direction away from the objective lens 120 as shown in FIG. 2 so that the two images P1 and P2 reach the reference position as shown in FIG. 5 (a).

Similarly, FIG. 4 shows a state in which the phase-division prism 140 has moved from the proper position to the eyepiece 130 side. At this time, two phases P1 and P2 separated by the phase- (See Fig. 5 (c)) in which the focus positions are shifted in the direction in which they overlap each other. Thus, in this state, the phase-splitting prism 140 is moved toward the objective lens 120 so that the gap between the two phases P1 and P2 is shifted in a widening direction, Can be set to reach.

Accordingly, when the objective lens 120 is collimated so as to face the flagpole and the two images P1 and P2 observed through the eyepiece 130 are spaced apart from each other, When the two images P1 and P2 are superimposed on each other, the phase splitting prism 140 is moved toward the objective lens 120 so that the lower part of the upper image P1 and the image of the lower image P2 It is possible to measure the distance to the flag by reading the scale of the distance display unit 150 corresponding to the setting position of the phase division prism 140 after adjusting the upper part to the reference position.

In other words, in the process of observing the flagpole through the enlarged image, the image is shaken by vibration such as hand tremble. However, since the two images P1 and P2 are moved together as if they are stuck together, Since it is easy to set the two phases P1 and P2 as the reference position and the scale provided outside the housing 110 is read in a state where the reference position setting is completed, not only can the scale be easily checked, Can be accurately measured.

Therefore, not only the conventional telescopic type golf distance measuring device but also the telescope or zoom lens of higher magnification can be applied, so that even if the image moves more severely, the distance can be measured regardless of the hand tremor, However, the distance to the flagpole can be measured quickly, easily, and precisely.

On the other hand, the equation for calculating the scale position of the scale plate for distance measurement as described above can be derived as follows. Assuming the symbols as below,

(

: The height of the flag pole,

: The size of the image formed on the image plane,

: The distance from the objective lens to the flag pole,

: The distance from the objective lens 120 to the image plane,

: The distance from the image plane to the phase splitting prism 140,

: The absolute value of the upper apex angle size of the phase splitting prism 140,

: The absolute value of the size of the lower apex angle of the phase splitting prism,

: A minimum angle of refraction of a ray passing through the upper portion of the phase splitting prism 140,

: A minimum angle of refraction of a ray passing through the lower portion of the phase splitting prism 140,

: Viewing angles looking at the ends of the flagpole,

: The focal length of the objective lens 120,

: The refractive index of the phase splitting prism 140)

--- (1)

The size of the image formed on the image plane

silver

--- (Equation 2)

When the vertex angle (positive angle) of the phase-division prism 140 is small, when the angle of deflection by the phase-division prism 140 is approximated to the minimum angle of refraction,

--- (Equation 3)

And the sum of the amounts of the deviation amounts of the two light beams passed through the lower portion and the upper portion of the phase-division prism 140 in the up-and-down direction on the image-forming surface (the direction in which the upper- (When the upper and lower apex angles of the phase-division prisms are in the same direction)

(4) is satisfied, it becomes a proper position.

Becomes an appropriate position of the prism.

--- (Equation 4)

When we rearrange equation (4)

--- (Equation 5)

Substituting Eqs. (2) and (3) into Eq. (5)

--- (Equation 6)

(Sign + sign is a phase division prism, sign + sign when the direction in which the lower apex angle is up and down is opposite direction, and sign - sign in the same direction)

Therefore, the distance to the flagpole

The proper position of the phase-splitting prism 140 for measuring the distance from the image-forming plane to the phase-splitting prism 140 as shown in equation (6)

. Therefore, based on Equation (6), it is possible to make a scale plate capable of measuring the distance to the object as shown in FIG.

That is, in the case of producing the scale 151 for each distance of the distance display unit 150 using the equation (6), the distance scale 151 of the distance display unit 150 using the equation (6) 1].

here,

(m), the proper position from the image position to the phase-division prism 140 when the flagpole is present is

(mm), and a scale plate can be manufactured using Table 1 as follows.

s (m) x (mm) 50 84.01 60 70.01 70 60.01 80 52.51 90 46.68 100 42.01 110 38.19 120 35.01 130 32.31 140 30.01 150 28.01 160 26.25 170 24.71 180 23.34 190 22.11 200 21.00 210 20.00

(Height of flag pole

, The focal length of the objective lens 120

, The upper apex angle of the phase splitting prism 140

The lower apex angle of the phase splitting prism 140,

, The refractive index of the phase splitting prism 140

Here, since the portion of the flagpole protruding above the ground surface is in a range of usually 2.1 m to 2.3 m, it is possible to use the standard value of the flagpole as a standard. In this embodiment, the average value of 2.2 m is applied I have heard. In addition, in order to measure more accurately, it is possible to measure the distance more precisely because it can reduce the error due to difference in the height of the flag by displaying the line of color which is well visible in the upper part and the lower part of the flagpole, There will be. Also, in order to make the measurement more convenient, the distance can be measured based on the size of the flag attached to the end of the flagpole instead of the flagpole. Also, in the present embodiment, the eyepiece lens is exemplified as a lens having a positive refractive power, but the same effect can be obtained for an eyepiece having a negative refractive power.

Next, modified embodiments of the distance measuring device using the phase-division prism according to the first embodiment of the present invention will be described.

A first modified example according to the first embodiment of the present invention is a modification of the first embodiment shown in Fig. 6A instead of the biprism type phase-division prism 140 used in Fig. 2 of the accompanying drawings, Differs from the first embodiment in that it is used in place of the phase-division prism 140a in the form of a multilayer-biprism-type phase-shifting prism 140a in which two inclined planes are alternately repeated, . When the position of the phase splitting prism is close to the objective lens 120 side, a big problem does not occur even if a biprism is used. However, when the phase-splitting prism approaches the image position of the objective lens (x becomes shorter), the image of the middle part of the flagpole is still divided into two parts as shown in Fig. 6 (b) Only the upper half or the upper half of the phase splitting prism passes through only the upper half or the lower half of the flagpole as shown in (c) of FIG. Therefore, in the area where x value is small, one of the flagpoles that should be separated into two parts looks sharp, while the other part shows a part of the flagpole, which may make the distance measurement inconvenient. In order to compensate for this, as shown in FIG. 6 (d), the phase-splitting prism is formed by alternately repeating two inclined surfaces having different slopes on at least one surface of the multi-layer biprism shown in FIG. 6 (a) differs from the first embodiment in that the image of the flagpole is clearly divided into two images even in the region where the x value is small by replacing the image with the phase-division prism 140a of the multilayer-biprism type.

A second modified example according to the first embodiment of the present invention is a modified example of a reticle 160 (see FIG. 7) in which an image of an objective lens 120 is formed between an eyepiece lens 130 and a phase- And the eyepiece lens 130 is finely adjustable along the optical axis direction so as to adjust the diopter according to the visual acuity of the observer through a reference mark (not shown) formed in the reticle 160, Differs from the above-described first embodiment in that the light source 120 is arranged to be finely adjustable along the optical axis direction so as to compensate for the focal length error according to the distance from the flagpole.

That is, the eyepiece 130 is finely adjusted in the direction of the optical axis according to the visual acuity of the observer to set the reference mark displayed on the reticle 160 to be clearly visible, and then the focal length of the objective lens 120, The objective lens 120 is finely adjusted in the direction of the optical axis so that a clear image is formed on the reticle 160.

Therefore, since the two images P1 and P2 separated by the phase splitting prism 140 can be observed in a clear state, it becomes possible to apply a high magnification telescope or a zoom lens, and the two images P1 , P2), it is possible to precisely measure the distance to the flagpole.

Next, a third modification according to the first embodiment of the present invention includes a control ring (not shown) rotatably installed in the housing 110 to move the phase-division prism 140 in the optical axis direction, A distance indicator 150 'is formed on the outer circumferential surface of the contact surface between the housing 110 and the control ring 170 and includes a reference mark 152 and a plurality of distance- Which is different from the first embodiment.

That is, when the adjustment ring 170 rotatably coupled to the housing 110 is rotated in the forward and reverse directions, the phase-division prism 140 disposed in the housing 110 moves in the optical axis direction, The distance between the two phases P1 and P2 separated by the distance between the two phases P1 and P2 is set as a reference position and the distance to the flagpole is determined by the distance scale 151 indicated by the reference marking line 152, It is possible to measure.

A prismatic prism such as a Schmidt-Pechen Prism may be disposed at an appropriate position between the objective lens 120 and the eyepiece 130 to fix the image when the refractive power of the eyepiece 130 is positive. 180 may be further disposed.

Next, a fourth modified embodiment according to the first embodiment of the present invention will be described with reference to FIG. 9 of the accompanying drawings, in which the distance indicator 150 '' is disposed inside the housing 110, The distance indicator 150 "according to the third modified embodiment is configured such that the distance scale 151 is displayed and the distance between the microlenses < RTI ID = 0.0 > 153 and a reflecting prism or reflector 154 for allowing the observer to observe a distance 151 for the distance between the ruler 153 and the upper prism 140 by the regulating ring 170 in the direction of the optical axis The micro scale 153 connected to the phase splitting prism 140 moves together and a scale 151 for the distance of the moved position is moved by the reflection prism or reflector 154 disposed on the upper side of the scale 153 And the focal length correction lens 155 to be reflected on the observer's retina Such that phase. The focal length correction lens 155 is disposed between the micro scale 153 and the reflective prism or reflector 154 to enlarge the distance scale 151 of the micro scale 153.

Accordingly, when the observer moves the adjustment ring 170 to measure the distance and adjusts the phase-division prism 140, the distance scale 151 according to the position of the phase-division prism 140 is reflected by the reflection prism or the reflector 154, So that it is possible to check the distance scale 151 in the distance measuring process.

In this case, since the distance scale 151 is integrally connected to the phase splitting prism 140, the distance scale 151 is moved together with the two phases separated by the phase splitting prism 140, It becomes possible to measure the distance to the flagpole quickly.

Next, a fifth modified embodiment according to the first embodiment of the present invention is characterized in that, as shown in FIG. 10 of the accompanying drawings, an optical path on the optical axis of the objective lens 120 and the eyepiece lens 130, 193 and 194 are disposed so that the image passing through the first to fourth reflectors 191 to 193 is incident on the center of the eyepiece lens 130 through the fourth reflector 194 .

A focal length correction lens 195 is disposed between the first reflector 191 and the second reflector 192 and a phase separation prism 140 is disposed between the second reflector 192 and the third reflector 193. [ A first diaphragm 196 is disposed between the third reflector 193 and the fourth reflector 194 to pass the central area of the image and to block the peripheral area of the image. 194, a second diaphragm 197 blocking the central area of the image is disposed.

When the optical system is constructed, two portions separated by the phase-splitting prism 140 and visible through the eyepiece 130 to the user's eye are separated into an image of the peripheral region as shown in FIG. 11 (a) And the image of the central region can be separately observed by the phase splitting prism 140. Therefore, in the course of obtaining an enlarged image using the objective lens 120, the environment around the hole can be easily grasped Provides an advantage.

On the other hand, the image observed through the eyepiece lens 130 is observed through the deformation of the first diaphragm 196 and the second diaphragm 197 so that the image of the flagpole is observed upward and downward as shown in FIG. 11 (b) Can be observed on both sides of the center.

In the above-described embodiment, the distance display unit 150 is displayed in the form of a scale. However, it is also possible to display the distance display unit 150 in a digital manner.

The sixth modified embodiment according to the first embodiment of the present invention is not shown in the drawing. Instead of using an eyepiece as the display means, an imaging element may be provided at a position where an image is formed by the objective lens, Which is different from the above-described first embodiment in that an image output unit interlocked with the device can be placed on the screen.

Next, a distance measuring apparatus using a phase-division prism according to a second embodiment of the present invention will be described.

12 is a cross-sectional view showing a configuration of a distance measuring instrument using a phase-division prism according to a second embodiment of the present invention, and Fig. 13 is a cross- Fig.

12, in the second embodiment of the present invention, the phase-splitting prism 140 'has a flat surface on the incident surface, a slant surface on the lower surface of the outgoing surface, and a deformed- Differs from the above-described embodiment in that it is formed of a prism 140 '.

The golf hole distance measuring instrument using the phase-splitting prism 140 'according to the second embodiment of the present invention passes through the upper region of the center of the optical axis through which the slope of the phase-division prism 140' The light beam passes through the plane of the phase splitting prism 140 'and forms an image at the focal position of the objective lens 120 without being refracted. A light ray passing through the lower region of the optical axis passes through the phase splitting prism 140' It is refracted while passing through the inclined plane, and the position of the image is shifted upward.

That is, in the second embodiment, as in the first embodiment, two phases P1 and P2 are formed, but the upper phase P1 is refracted by the objective lens 120 to form an image, The phase difference prism 140 is refracted by the inclined surfaces of the objective lens 120 and the phase splitting prism 140 'to form an image by using the two images P1 and P2. ) Is moved in the direction of the optical axis, only the lower image P2 moves upward and downward.

Therefore, in the process of moving the phase-division prism 140 'in the direction of the optical axis to set the reference position using the two images P1 and P2, the upper image P1 is held in place, (P2) are moved in the upward and downward directions. Since the two phases are prevented from moving as in the first embodiment, it is possible to improve the usability.

However, the present invention is not limited to this, and it is also possible to arrange the inclined surface on the upper surface of the upper surface with reference to the optical axis, It is also possible to form the phase-division prism 140 'in such a manner that a sloped surface is formed on both sides of the prism 140 or the sloped surface is turned upside down.

In addition, a plane that does not refract light is formed on both sides of the opposite side of the center of the optical axis on which the oblique plane of the phase-division prism 140 'is not formed, thereby facilitating the position of the phase-division prism 140' .

If only half of the phase-division prism 140 'is used with reference to the optical axis as shown in FIG. 12, since there is only one vertex angle on the lower side,

Apical

Leave the lower apex .

That is, in the case of producing the scale 151 for each distance of the distance display unit 150 using the equation (6), the distance scale 151 of the distance display unit 150 using the equation (6) 2].

s (m) x (mm) 50 83.96 60 69.96 70 59.97 80 52.47 90 46.64 100 41.98 110 38.16 120 34.98 130 32.29 140 29.99 150 27.99 160 26.24 170 24.69 180 23.32 190 22.09 200 20.99 210 19.99

(Height of flag pole

, The focal length of the objective lens 120

, The upper apex angle of the phase splitting prism 140 '

, The lower apex angle of the phase splitting prism 140 '

, The refractive index of the phase splitting prism 140 '

As shown in Fig.

On the other hand, as shown in Fig. 14, a first modified example according to the second embodiment of the present invention is a modification of the second embodiment of the present invention, in which a phase-division prism 140 "disposed on the optical path between the objective lens 120 and the eyepiece 130, An effect similar to that of the second embodiment can be expected in the case of being disposed at an upper portion or a lower portion of the center and forming an inclined surface whose inclination is opposite to the front and rear of the optical axis.

In addition, although not shown in the drawing, it is also possible to replace the phase-division prisms 140a, 140 ', and 140 "described above with the positions of the phase-division prism 140 of the optical system as shown in FIG.

The scope of the present invention is not limited to the above-described embodiments, but may be embodied in various forms of embodiments within the scope of the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

110: housing, 120: objective lens, 130: eyepiece,
140, 140 ', 140 ": phase-division prism, 150, 150', 150": distance display unit,
151: distance scale, 152: reference line, 153: ruler,
154: reflection prism or reflector, 155: focal length correction lens, 160: reticle,
170: regulating ring, 180: prism, 191: first reflector,
192: second reflector, 193: third reflector, 194: fourth reflector,
195: focal length correction lens, 196: first stop, 197: second stop

Claims

A tubular housing having front and rear openings;
A double-letter-type objective lens composed of two aspherical lenses arranged at the front end of the housing so as to face the distance measurement object;
Display means for providing an image on the objective lens side to a user;
A phase splitting prism disposed between the objective lens and the display means to separate and form an image on the objective lens side and to be movable in the optical axis direction in the housing so as to adjust the interval between the separated images; And
And a distance display unit for displaying the distance from the object to be measured according to the position of the phase division prism in a state in which the position of the phase division prism is adjusted so that the interval between the separated phases is set at the reference position, .

The method according to claim 1,
Wherein the objective lens of the doublet type is composed of a BK series and a SF series of lenses.