JP3131826B2 - Upright / branch optical system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an erecting / branching optical system used for telescopes, surveying instruments, and the like.

[0002]

2. Description of the Related Art Conventional telescope optical systems used in telescopes, surveying instruments and the like have an erecting optical system between an objective optical system and an eyepiece optical system. In such a telephoto optical system in which an automatic focusing device is mounted, a branching optical system is arranged in the middle of the telephoto optical system, and a part of the object field light beam is branched toward the automatic focusing device. FIG. 8 shows an optical configuration of a collimating telescope of a conventional surveying instrument equipped with an automatic focus detection device. In this collimating telescope, a collimating objective lens group 11, a focusing lens group 12, an erecting optical system (type 2 Porro prism) 13, a branch optical system 15, a reticle (focusing plate) ) 17 and an eyepiece 19. The object light beam transmitted through the objective optical system 11 is erected by the erecting optical system 13 and
5, an erect real image is formed on the reticle 17 in a focused state. The surveyor magnifies and observes the erect object image on the reticle 17 via the eyepiece lens 19 while superimposing the image on the reticle.

On the other hand, an AF sensor unit 21 for detecting a focus state of a subject image on a predetermined focal plane a equivalent to the focal plane A on the reticle 17 is arranged for the subject light beam branched by the branch optical system 15. . This AF sensor unit 21
Has a well-known configuration, and detects a defocus amount, a front focus, and a rear focus of a subject by, for example, a phase difference method. Then, based on the detection result, the control means (microcomputer) 23 drives the motor M, and the rack & pinion mechanism 2
The focus adjustment is performed by moving the focus adjustment lens group 12 back and forth along the optical axis via the control unit 5.

In a surveying instrument, maintenance of an optical system, for example, an erecting optical system 13, a branching optical system 15, a reticle 1
The cleaning and replacement of the reticle 7 and the position adjustment of the reticle 17 may be performed. If such maintenance is performed, these optical axes may be out of order, so that the axis adjustment may be required. At the time of such adjustment, in the conventional optical system configuration, adjustment of the erecting optical system 13 and the branching optical system 15 is particularly troublesome.
That is, when the erecting optical system 13 is moved, the erecting optical system 13 is moved.
Since the position of the chief ray incident on the branch optical system 15 behind is shifted, the position of the chief ray split by the split optical system 15 and incident on the AF sensor unit 21 is also shifted. Therefore, the adjustment of the position of the erecting optical system 13 must be performed simultaneously with the adjustment of the reticle 17 and the adjustment of the position of the AF sensor unit 21 having an equivalent relationship, and the adjustment is troublesome.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problem of a telephoto optical system having an automatic focusing device, and is suitable for a telephoto optical system having an automatic focusing device, and has an easy position adjustment. -To provide a branch optical system.

[0006]

According to the first aspect of the present invention, which achieves the above object, an entrance end face of a type 2 Porro prism is closely attached to an exit end face of a type 1 Porro prism as an erecting optical system, and from the entrance end face. A diverging optical element that forms a luminous flux splitting surface that divides the luminous flux incident on the reflecting surface by reflection and transmission outside the reflecting surface on which the luminous flux incident on the type 2 Porro prism is first reflected; Is formed on a plane parallel to the incident end face of the 2-type Porro prism.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an embodiment of an optical configuration of a collimating telescope provided with an automatic focusing device of a surveying instrument to which the present invention is applied. Members having the same functions as those of the optical elements and electronic components shown in FIG. 8 are denoted by the same reference numerals, and description thereof will be omitted. This collimating telescope, in order from the object side,
A collimating objective lens group 11 and a focus adjusting lens group 12, an erecting / branching optical system 31 having functions as an erecting optical system and a branching optical system, a reticle (focusing plate) 17, and an eyepiece 19 as an objective optical system. Have. The object light beam transmitted through the objective optical system 11 is erected by the erecting / branching optical system 31, and is mostly transmitted therethrough. The object light beam is erected on the reticle 17 in the focused state, and at the front and rear positions in the unfocused state. A real image (focused state) is formed. The surveyor uses the eyepiece 19
The magnified observation of the erect object image on the reticle 17 is performed by superimposing the image on the reticle.

On the other hand, the light beam for focus detection is branched from the observation light beam in the erecting / branching optical system 31, exits from the erecting / branching optical system 31 via another optical path, and is transmitted to the AF sensor unit 21. Incident. The AF sensor unit 21 detects the focus state of the subject image on the secondary imaging plane of the scheduled focal plane a equivalent to the reticle 17 at a position equivalent to the reticle 17. There are various known focus detection methods. For example, a defocus amount, a front focus, and a rear focus of a subject are detected by a phase difference method. Then, based on the detection result, the control means (microcomputer) 23 drives the motor M to move the focus adjustment lens group 12 back and forth along the optical axis via the rack and pinion mechanism 25 to perform focus adjustment. .

A more detailed configuration of the erecting / branching optical system 31 will be described with reference to the first embodiment shown in FIGS. In the first embodiment, a 2-type Porro prism (Poro-prism type 2) 33 as an erecting optical system includes
This is an embodiment to which a mold Porro prism 35 (Poro prism 1 type) is applied. FIG. 2 is a perspective view of the erecting / branching optical system 31, and FIG. 3 is an exploded perspective view showing a prism of the erecting / branching optical system 31.

The two-type Porro prism 33 is formed by three right-angle prisms P1, P2 and P3,
5 is formed of two right-angle prisms P4 and P5. In this embodiment, the incident end face I2 of the first type Porro prism 35 is bonded to the exit end face E1 of the second type Porro prism 33. The light exits from the exit end face E1 of the second type Porro prism 33, and the incident end face I2 of the first type Porro prism 35.
On the outer surface of the reflection surface R5 where the light beam incident from the first is reflected, the transmitted light beam toward the reticle 17 and the reflection in the 1-type porro prism 35 are repeated to output the AF sensor unit 21 from the exit end face E2 of the 1-type porro prism 35. A branching prism P6 that forms a light beam splitting surface by transmission and reflection is bonded to the reflected light beam that is emitted toward.

Each prism P1 of the erecting / branching optical system 31
The prism P6 reflects and transmits the incident light beam as described below. A description will be given with the symbol L attached to the axial rays of the collimating objective lens group 11 and the focus adjusting lens group 12, that is, the principal rays that are perpendicularly incident on the center of the incident end face I1. In FIG. 2, the optical axis is the Z axis, the horizontal direction is the X axis, and the vertical direction is the Y axis.

The incident principal ray L1 transmitted through the collimating objective lens group 11 and the focusing lens group 12 enters the erecting / branching optical system 31 from the entrance end face I1 of the type 2 Porro prism 33, and the first reflecting surface. R1 reflects downward at a right angle and travels parallel to the Y axis (principal ray L2), and is reflected at a right angle in the horizontal direction at the second reflection surface R2 and travels parallel to the X axis (principal ray L3).
The light is reflected upward at a right angle on the reflection surface R3 (reflects and travels parallel to the Y axis (principal ray L4)), and reflected at a right angle forward on the fourth reflection surface R4 and travels toward the eyepiece lens 19 parallel to the Z axis (emission). The principal ray L5) emerges from the exit end face E1 of the second type Porro prism 33 and enters the first type Porro prism 35 at the incident end face I2 (prism P
4 bottom surface).

A part of the principal ray L5 incident on the type 1 Porro prism 35 (prism P4) is transmitted through the fifth reflecting surface R5 and the incident end face I3, and is perpendicular to the reticle 1 from the exit end face E3.
7. The light exits toward the eyepiece lens 19 (the emission principal ray L
5). On the other hand, the remaining part of the principal ray L5 incident on the fifth reflecting surface R5 is reflected upward at a right angle and travels parallel to the Y axis (branch principal ray L6), and the other sixth reflection of the prism P4. The light is reflected rearward at right angles on the surface R6, travels in parallel with the Z-axis, enters the prism P5 (branch principal ray L7), and is reflected at right angles in the horizontal direction on the seventh reflection surface R7 of the prism P5 and parallel to the X-axis. (Branch principal ray L8), reflected forward at a right angle on the eighth reflecting surface R8, and travels parallel to the Z-axis (branch exit principal ray L8).
9) The light exits perpendicularly from the exit end face E2 and enters the AF sensor unit 21.

Here, the principal rays L3 and L8 are parallel to the X axis, and the principal rays L2, L4 and L6 are coincident with or parallel to the Y axis.

FIG. 6 shows the state of the emitted light beams L5 and L9 when the erecting / branching optical system 31 is moved in a direction (XY axis direction) perpendicular to the optical axis for position adjustment. A),
Description will be made based on (B). The erecting / branching optical system 31
Although not shown, an X orthogonal to the optical axis is set with respect to the lens barrel.
The axis and Y-axis directions can be adjusted, and the reticles 17 and 21 are fixed to the lens barrel and do not move.

When the erect / branch optical system 31 (33, 35) is moved by .DELTA.x to the right in the horizontal direction (along the X axis) in the figure, the exit chief ray L5 is changed to the erect / branch optical system. It moves twice in the same direction as 31 (33), that is, it moves 2Δx to the right in the figure. However, the branch exit light beam L9 is 3
Since it moves 2Δx in the opposite direction with respect to 5, the movement amount is eventually canceled out and it does not move in the horizontal direction.

Similarly, when the erecting / branching optical system 31 moves in the vertical direction (along the Y axis) by Δy, the emission principal ray L5 moves twice, ie, 2Δy, in the same direction as the erecting / branching optical system 31. However, the branched exit light beam L9 is relatively shifted by 2Δy in the opposite direction.
Since it moves, the movement amount is offset and does not move.

As described above, in the first embodiment, even if the erecting / branching optical system 31 is moved in parallel in a direction perpendicular to the Z axis, the emission chief ray L
Since 9 does not move, it is not necessary to coordinate the position adjustment of the reticle 17 and the eyepiece lens 19 and the position adjustment of the AF sensor unit 21 with each other, and these position adjustments become very easy.

FIGS. 4 and 5 show still another embodiment of the present invention. The second embodiment is an erecting / branching optical system 41 in which a 2-type Porro prism 45 is applied to a 1-type Porro prism 43 as an erecting optical system.

The 1-type Porro prism 43 is formed by two right-angle prisms P21 and P22,
Is formed by three right-angle prisms P23, P24 and P25. In the second embodiment, the entrance end face I22 of the second type Porro prism 45 is bonded to the exit end face E21 of the first type Porro prism 43. The luminous flux emitted from the exit end face E21 of the first type Porro prism 43 and incident on the incident end face I22 of the second type Porro prism 45 is transmitted to the reticle 17 on the outer surface of the reflection surface R25 where the light flux is first reflected. A splitting prism that forms a light beam splitting surface that is split by transmission and reflection into a reflected light beam that is reflected in the second type Porro prism 45 and emitted from the exit end face E22 of the second type Porro prism 45 toward the AF sensor unit 21 P26 is adhered.

Each prism P21 of the erecting / branching optical system 41
-Prism P26 reflects and transmits the incident light beam as follows. A description will be given with the symbol L attached to the axial rays of the collimating objective lens group 11 and the focusing lens group 12, that is, the principal ray that is perpendicularly incident on the center of the incident end face I21. 4 and 5, the optical axis is the Z axis, the horizontal direction is the X axis,
Let the vertical direction be the Y axis.

The incident principal ray L21 transmitted through the collimating objective lens group 11 and the focusing lens group 12 is transmitted to the erecting / branching optical system 41 by the entrance end face I21 of the type 1 Porro prism 43.
From the first reflecting surface R21, the light is reflected at right angles in the horizontal direction at the first reflecting surface R21, and travels in parallel with the X axis (principal ray L22).
2, the light is reflected backward at a right angle and travels parallel to the Z axis (the principal ray L
23), the light is reflected upward at a right angle by the third reflecting surface R23 and travels parallel to the Y axis (principal ray L24), and is reflected at a right angle forward by the fourth reflecting surface R24 and travels parallel to the Z axis (primary ray). Ray L2
5) The light exits from the exit end face E21 of the first type Porro prism 43 and enters the second type Porro prism 45 (prism P23) from the incident end face I22.

The principal ray L incident on the type 2 Porro prism 45
25 is a reticle 17, a part of which passes through the prism P23 and the prism P26 from the exit end face E23, and the eyepiece 1;
Inject toward 9 On the other hand, the type 2 Porro prism 45
The remaining portion of the principal ray L25 incident on the (prism P23) is reflected at a right angle on the boundary surface between the prisms P23 and P24, advances parallel to the Y axis (principal ray L26), enters the prism P24, The light is reflected at a right angle by the reflecting surface R26 and travels in parallel with the X axis (principal ray L27), and the seventh reflecting surface R27
Reflected downward at a right angle and travels parallel to the Y axis (chief ray L2
8) The light is reflected forward at a right angle on the eighth reflection surface R28, travels in parallel with the Z axis, and exits from the exit end surface E22 of the prism P25 toward the AF sensor unit 21 (the exit principal ray L29).

Thus, the incident principal rays L21, L23,
The exit chief rays L25 and L29 are coincident or parallel with the Z axis, the principal rays L22 and L27 are coincident or parallel with the X axis, and the principal rays L26 and L28 are coincident or parallel with the Y axis. When the erect / branch optical system 41 is moved in a direction perpendicular to the Z axis for position adjustment, the emitted light L
The states of 25 and L29 will be described with reference to FIGS.

The erecting / branching optical system 41 (porro prism 4)
3, 45) in the horizontal direction (along the X-axis) in the figure to the position indicated by the broken line by Δx, the emission principal ray L
25 moves twice in the same direction as the erecting / branching optical system 41, that is, moves 2Δx to the right. However, the branch exit light beam L29 is
Since it moves 2Δx in the opposite direction with respect to the type 2 porro prism 45, the moving amount is eventually canceled out and it does not move in the horizontal direction. Similarly, the erecting / branching optical system 41 (porro prism 4
(3, 45) in the vertical direction (along the Y axis) by Δy, the exit principal ray L25 moves twice, that is, 2Δy, in the same direction as the type 1 Porro prism 43. However, the branch exit light beam L29 is 2Δ in the opposite direction with respect to the type 2 Porro prism 45.
Since it moves by y, the amount of movement is eventually cancelled, and it does not move in the horizontal direction.

As described above, according to the present embodiment, the erecting
Even if the branch optical system 31 and the erecting / branching optical system 41 are moved in a direction perpendicular to the optical axis, the light beam incident on the reticle 17 moves, but the light beam incident on the AF sensor unit 21 does not move. If the position adjustment of the AF sensor unit 21 is performed, even if the position adjustment with respect to the reticle 17 and the eyepiece 19 is performed, the incident position of the principal ray on the AF sensor unit 21 will not be out of order. Therefore, the position adjustment of the erecting / branching optical systems 31 and 41 becomes very easy.

In the illustrated embodiment, the present invention is applied to a surveying instrument equipped with an automatic focusing device. However, the present invention is not limited to this embodiment, and a telescope equipped with an automatic focusing device, binoculars, etc. It can be easily understood that the present invention is applied to the optical device. Also, instead of the AF sensor unit 21,
Alternatively, instead of the reticle 17 and the eyepiece optical system 21,
The present invention can also be applied to an optical device that includes an image pickup device such as a CCD image pickup device and observes an image picked up by the image pickup device. In the embodiment, the 1-type Porro prism and the 2-type Porro prism are used. However, 1-type Porro prism and 2-type Porro prism can be used.
The relative orientation of the type 1 Porro prism and the type 2 Porro prism is free as long as the exit end face and the entrance end face are in close contact.

[0028]

As is clear from the above description, the present invention
The incident end face of the type 2 Porro prism or the type 1 Porro prism is closely adhered to the exit end face of the type 1 Porro prism or the type 2 Porro prism as the erecting optical system, and from the incident end face to the type 2 Porro prism or the type 1 Porro prism. A branch optical element for forming a light beam splitting surface for splitting a light beam incident on the reflecting surface by reflection and transmission is arranged outside a reflecting surface on which the incident light beam is first reflected. Since it is formed parallel to the exit end face of the type Porro prism or type 2 Porro prism, even if the type 1 and type 2 Porro prisms and the branch optical element are moved in the direction perpendicular to the optical axis, the light exits from the exit end face of the branch optical element. The luminous flux that travels in parallel moves, but the luminous flux emitted from the exit end face of the 2-type Porro prism or the 1-type Porro prism does not move. Adjustment of the position of the splitting optical system becomes easy.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment in which an erect / branch optical system of the present invention is applied to a surveying instrument provided with an automatic focusing device.

FIG. 2 is a perspective view showing an appearance of the erecting / branching optical system according to the first embodiment.

FIG. 3 is a perspective view showing an appearance of the erecting / branching optical system according to the first embodiment, with a prism separated.

FIG. 4 is a perspective view showing an appearance of an erect / branch optical system according to the second embodiment.

FIG. 5 is a perspective view showing an appearance of the erecting / branching optical system according to the second embodiment, with a prism separated.

FIGS. 6A and 6B are views for explaining the position adjustment of the erect / branch optical system when the erect / branch optical system according to the first embodiment is applied, wherein FIG. 6A is a plan view and FIG. () Is a view of the erecting / branching optical system viewed from the eyepiece side.

FIGS. 7A and 7B are views for explaining the position adjustment of the erect / branch optical system when the erect / branch optical system according to the second embodiment is applied, wherein FIG. 7A is a plan view and FIG. () Is a view of the erecting / branching optical system viewed from the eyepiece side.

FIG. 8 is a diagram illustrating an outline of an optical system of a surveying instrument including a conventional automatic focusing device.

[Explanation of symbols]

 17 Reticle 19 Eyepiece 21 AF Sensor Unit (Focus Detecting Means) 31 Erect / Branch Optical System 33 2 Type Porro Prism 35 1 Type Porro Prism P6 Right Angle Prism (Branch Optical Element) 41 Erect / Branch Optical System 43 1 Type Polo Prism 45 Type 2 Porro prism P26 Right angle prism (branching optical element)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI G02B 23/04 G02B 23/04 27/10 27/10 (58) Investigated field (Int.Cl. ⁷ , DB name) G02B 5 / 04 G02B 23/04 G02B 27/10

Claims (11)

(57) [Claims] An incident end face of a type 2 Porro prism is closely attached to an exit end face of a type 1 Porro prism as an erecting optical system, and a reflecting surface from which a light beam incident on the type 2 Porro prism from the incident end face is first reflected. A branching optical element that forms a light beam splitting surface that splits a light beam incident on the reflecting surface by reflection and transmission is disposed outside the light source, and the exit end face of the splitting optical element is parallel to the incident end face of the 2-type Porro prism. An erecting / branching optical system characterized by being formed on a flat surface. 2. A principal ray which is perpendicularly incident on the incident end face of the 1-type Porro prism, and among the principal rays, an exit ray which passes through the light beam splitting surface and exits, and which is reflected by the light beam splitting surface. 2. The erecting / branching optical system according to claim 1, wherein the light beams emitted from the emission end face of the two-type Porro prism are parallel to each other. 3. The erecting / branching optical system according to claim 1, wherein the branch optical element is a right-angle prism having a bottom surface at the exit end face and a slope at a surface in close contact with the reflection surface. 4. A telephoto optical system comprising the erecting / branching optical system according to claim 1, wherein the telephoto optical system includes an objective optical system and the A focus detection unit that includes a branching optical system and an observation optical system, and that receives a light beam emitted from the light-emitting surface of the two-type Porro prism and reflected by the light beam branch surface to detect and focus.
A telephoto optical system equipped with an erecting / branching optical system. 5. A telephoto optical system comprising the erecting / branching optical system according to claim 1, wherein the telephoto optical system includes an objective optical system and the An erecting device comprising: a branching optical system and an observation optical system; and an imaging means for receiving and imaging an exiting light beam reflected from the light beam branching surface and exiting from the exit end surface of the type 2 Porro prism. -A telephoto optical system with a branch optical system. 6. An incident end face of a 1-type Porro prism is closely attached to an exit end face of a 2-type Porro prism as an erecting optical system, and a reflecting surface from which a light beam incident on the 1-type Porro prism from this incident end face is first reflected. A branching optical element that forms a light beam splitting surface that splits a light beam incident on the reflecting surface by reflection and transmission is disposed outside the light source, and the exit end face of the splitting optical element is parallel to the incident end face of the 2-type Porro prism. An erecting / branching optical system characterized by being formed on a flat surface. 7. A principal ray that is perpendicularly incident on the incident end face of the type 2 Porro prism, and among the principal rays, an exit ray that passes through the light beam splitting surface and exits, and is reflected by the light beam splitting surface. 7. The erecting / branching optical system according to claim 6, wherein the light rays emitted from the exit end face of the 1-type Porro prism are parallel to each other. 8. The erecting / branching optical system according to claim 7, wherein the branch optical element is a right-angle prism having the exit end surface as a bottom surface and a surface in close contact with the reflection surface as a slope. 9. A telephoto optical system comprising the erecting / branching optical system according to claim 6, wherein the telephoto optical system includes, in order from an object side, an objective optical system, A focus detection unit that includes a splitting optical system and an observation optical system, and that receives a light beam emitted from the light-emitting surface of the 1-type Porro prism and reflected by the light beam branch surface, and focus-detects the light beam;
A telephoto optical system equipped with an erecting / branching optical system. 10. A telephoto optical system comprising the erecting / branching optical system according to claim 6, wherein the telephoto optical system includes an objective optical system and the An erecting device comprising: a branching optical system and an observation optical system; and an imaging means for receiving and imaging an exiting light beam reflected from the light beam branching surface and exiting from the exit end face of the 1-type Porro prism. -A telephoto optical system with a branch optical system. 11. An entrance end face of another Porro prism is closely adhered to an exit end face of a Porro prism as an erecting optical system, and a light beam incident on the other Porro prism from this entrance end face is outside a reflection surface for first reflection. In this, a branching optical element forming a light beam branching surface that branches the light beam incident on the reflecting surface by reflection and transmission is arranged, and the exit end face of the branching optical element is
An erect / branch optical system formed on a plane parallel to the entrance end face of the Porro prism.