JP5263660B2 - Alignment device and optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alignment device capable of aligning a main mirror and a sub mirror in spite of simple and inexpensive constitution. <P>SOLUTION: The alignment device is a device for aligning the main mirror 10 and the sub mirror 20 in an optical system including the main mirror 10 having an aperture 10a formed on an optical axis AX and the sub mirror 20 arranged oppositely on the optical axis AX of the main mirror 10, and includes an optical member 30 having a light reflecting function, and a detection system 40 detecting misalignment between the main mirror 10 and the sub mirror 20 based on alignment light which is made incident from the aperture 10a of the main mirror 10 in a state of parallel beams parallel with the optical axis AX, passes through a reflection surface 21 of the sub mirror 20 and a reflection surface 11 of the main mirror 10 in this order, is reflected and folded by the optical member 30, passes through the reflection surface 11 of the main mirror 10 and the reflection surface 21 of the sub mirror 20 in this order and is emitted from the aperture 10a of the main mirror 10. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an alignment apparatus, and more particularly to alignment (positioning) between a primary mirror and a secondary mirror provided in a laser optical apparatus such as a laser irradiation apparatus and a laser distance measuring apparatus.

As this type of laser optical device, for example, as described in Japanese Patent Application Laid-Open No. 2002-121724, a light transmission optical system that transmits laser light toward the sky, and scattering of laser light transmitted from the light transmission optical system 2. Description of the Related Art A laser radar device including a light receiving optical system that receives laser light is known. In addition, an alignment optical system that can be used to align the primary mirror and the secondary mirror of the Cassegrain optical system in a laser optical apparatus that employs a large-aperture reflection optical system, such as a laser radar apparatus, is disclosed.
US Patent Application Publication No. 2006 / 0279838A1

  By the way, Patent Document 1 proposes an alignment optical system using an annular spherical mirror as a null optical system laid so as to be in close contact with the peripheral portion of the secondary mirror. However, this configuration has the disadvantage that it is difficult to manufacture a spherical mirror and a secondary mirror that are in close contact with each other. Further, there is an inconvenience that the central shielding amount of the light flux increases by the area of the null spherical mirror.

  Patent Document 1 proposes an alignment optical system using a perforated plane mirror having a large aperture comparable to that of the main mirror and a large central through-hole. However, this configuration has a disadvantage in that the amount of transmitted light and the amount of received light are impaired by the area of a large-diameter perforated plane mirror. In addition, it is difficult to manufacture and install a large-diameter perforated plane mirror with a desired accuracy, resulting in a large cost.

  The present invention has been made in view of such a problem, and an object thereof is to provide an alignment apparatus capable of aligning a primary mirror and a secondary mirror with a simple and low-cost configuration. .

In order to achieve such an object, according to a first aspect illustrating the present invention, in an optical system having a primary mirror and a secondary mirror arranged to face each other along the optical axis, the primary mirror An alignment device for aligning the secondary mirror with the secondary mirror, an optical member having a light reflecting function, and a parallel beam parallel to the optical axis is incident on the secondary mirror, and the reflective surface of the secondary mirror And the primary mirror and the secondary mirror based on the alignment light that passes through the reflective surface of the primary mirror in order, is reflected by the optical member and is folded back, and sequentially passes through the reflective surface of the primary mirror and the reflective surface of the secondary mirror. The alignment apparatus is provided , wherein the secondary mirror is fixedly held by the optical member .

  Moreover, according to the 2nd aspect which illustrates this invention, the optical system which has a primary mirror and a submirror arrange | positioned so that it may oppose along an optical axis, and the alignment apparatus of a 1st aspect are provided. An optical device is provided.

  As described above, according to the present invention, it is possible to provide an alignment apparatus capable of aligning a primary mirror and a secondary mirror with a simple and low-cost configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a configuration of an alignment apparatus according to the present embodiment. The alignment apparatus according to the present embodiment includes a primary mirror having an opening formed on an optical axis, such as a laser optical apparatus such as a laser radar apparatus, and a secondary mirror disposed to face the optical axis of the primary mirror. 1 is an alignment device for aligning the primary mirror and the secondary mirror, and as shown in FIG. 1, the primary mirror 10, the secondary mirror 20, and the optical member 30 And a detection system 40 and an attitude control mechanism 50.

  The primary mirror 10 is a concave mirror having an opening 10a formed on the optical axis AX and a concave reflecting surface 11 formed on the front side (sub mirror 20 side). The secondary mirror 20 is a convex reflecting mirror having a convex reflecting surface 21 that is disposed opposite to the optical axis AX of the primary mirror 10 and formed on the front side (primary mirror 10 side). That is, the primary mirror 10 and the secondary mirror 20 constitute a so-called Cassegrain optical system.

  The optical member 30 has a reflection function and a transmission function with respect to light incident on the member.

  The alignment apparatus according to the present embodiment is housed in a housing 60 having a window 60a through which light transmitted through the optical member 30 can pass, and the optical member 30 is disposed in the window 60a. According to this configuration, the airtightness of the housing 60 can be improved, and the optical system and electrical components (not shown) housed in the housing 60 can be protected from external factors such as wind and rain and condensation.

  The optical member 30 holds the secondary mirror 20 in a fixed manner. With this configuration, a truss or the like for holding the secondary mirror 20 becomes unnecessary, a simple device configuration can be achieved by reducing the number of parts, and cost can be reduced.

  The surface shapes of the primary mirror 10, the secondary mirror 20, and the optical member 30 are such that the alignment light incident from the opening 10a of the primary mirror 10 passes through the reflective surface 21 of the secondary mirror 20 and the reflective surface 11 of the primary mirror 10 in order. The incident light path reaching 30 and the alignment light reflected and folded back by the optical member 30 sequentially pass through the reflecting surface 11 of the primary mirror 10 and the reflecting surface 21 of the secondary mirror 20, and then reach the opening 10a of the primary mirror 10. Is set to match.

  The detection system 40 is provided on the optical axis AX, and a beam splitter 41 that divides the alignment light emitted from the opening 10a of the main mirror 10, and a collector that condenses the alignment light divided by the beam splitter 41 on a predetermined surface. A detection surface is positioned on the predetermined surface by the optical optical system 42, and a detection position of the alignment light on the detection surface is detected. For example, a photodetector 43 such as a two-dimensional CCD, and detection by the photodetector 43 By comparing the focused position of the alignment light with a preset reference position, a positional deviation between the primary mirror 10 and the secondary mirror 20 (for example, a shift in a direction perpendicular to the optical axis AX, or an optical axis AX) And a data processing device 44 that generates an alignment adjustment signal such that the difference between the light collection position and the reference position is “zero”.

  Specifically, the attitude control mechanism 50 adjusts the alignment adjustment signal output by the data processing device 44 so that the optical axes of the primary mirror 10 and the secondary mirror 20 match based on the detection result of the detection system 40. Based on the above, at least the position and orientation of either the primary mirror 10 or the secondary mirror 20 are controlled (in FIG. 1, an example in which the control target is the primary mirror 10 is given).

  The alignment apparatus further includes a light source L and a dichroic mirror M. The light source L supplies alignment light having an annular cross section, for example. The dichroic mirror M is provided between the light source L and the beam splitter 41 on the optical axis AX, transmits the alignment light, and reflects the use light of the Cassegrain optical system including the primary mirror 10 and the secondary mirror 20. To do.

  In the usage state of the laser radar device in the present embodiment, as shown in FIG. 2, when light is transmitted, the laser light supplied from a laser light source (not shown) is reflected by the dichroic mirror M and passes through the beam splitter 41. Then, the light is guided to the Cassegrain optical system (primary mirror 10 and secondary mirror 20). The laser light guided to the Cassegrain optical system (primary mirror 10 and secondary mirror 20) is incident from the opening 10a of the primary mirror 10 and sequentially passes through the reflective surface 21 of the secondary mirror 20 and the reflective surface 11 of the primary mirror 10. After passing through the optical member 30, for example, the light is transmitted toward the sky in the target direction in the state of a light beam parallel to the optical axis AX).

  In the case of receiving light, the scattered laser light from the target irradiated with the laser light passes through the optical member 30 and sequentially passes through the reflective surface 11 of the primary mirror 10 and the reflective surface 21 of the secondary mirror 20. 10 passes through the aperture 10a, passes through the beam splitter 41, is reflected by the dichroic mirror M, and then received by a light receiving unit (not shown). In the light receiving unit, for example, the intensity and return time of the received scattered laser light is detected to detect the state of the measurement target.

  In the alignment apparatus of the present embodiment, as shown in FIG. 3, the alignment light emitted from the light source L sequentially passes through the dichroic mirror M and the beam splitter 41, and is parallel to the optical axis AX from the opening 10a of the main mirror 10. It enters in the state of a parallel light beam, passes through the reflecting surface 21 of the secondary mirror 20 and the reflecting surface 11 of the primary mirror 10 in order, is reflected by the optical member 30 and is folded back, and is reflected by the reflective surface 11 of the primary mirror 10 and the secondary mirror 20. After passing through the surface 21 in order, the light exits from the opening 10 a of the primary mirror 10 and then enters the beam splitter 41. The alignment light reflected by the beam splitter 41 is condensed on the detection surface of the photodetector 43 via the condensing optical system 42, and the photodetector 43 detects the condensing position of the alignment light on the detection surface. The detection result is output to the data processing device 44. The data processing device 44 calculates the positional deviation between the primary mirror 10 and the secondary mirror 20 by comparing the focusing position of the alignment light detected by the photodetector 43 with a preset reference position. An alignment adjustment signal is generated based on the result.

  For example, in a laser radar apparatus, when the primary mirror 10 and the secondary mirror 20 are accurately aligned along the optical axis AX, the beam is emitted from the secondary mirror 20 (through the opening 10a of the primary mirror 10). The alignment light that has returned to the splitter 41 is in a state of a parallel light beam with respect to the optical axis AX, as is the case with the alignment light that has entered the secondary mirror 20 from the beam splitter 41 (through the opening 10a of the primary mirror 10). Therefore, the alignment light forms a small spot light at a predetermined reference position (for example, the center position of the detection surface) intersecting the optical axis AX on the detection surface of the photodetector 43 by the condensing optical system 42. At this time, since the condensing position of the alignment light (spot light position) detected by the photodetector 43 matches the reference position, the data processing device 44 determines that the condensing position of the spot light and the reference position are the same. An alignment adjustment signal indicating that the difference is “zero” is generated and output to the attitude control mechanism 50.

  On the other hand, in a state where the primary mirror 10 and the secondary mirror 20 are relatively displaced, the alignment light forms spot light on the detection surface of the photodetector 43 at a position deviating from a predetermined reference position. At this time, the light detector 43 detects the condensing position of the alignment light (spot light position information), and the data processor 44 determines whether the alignment light and the predetermined reference position are based on the detection result of the light detector 43. The positional deviation, that is, the positional deviation between the primary mirror 10 and the secondary mirror 20 is calculated, and an alignment adjustment signal is generated so that the difference between the condensing position of the alignment light and the reference position becomes “zero”, and the attitude control mechanism 50 Output to.

  The attitude control mechanism 50 controls the position and attitude of at least one of the primary mirror 10 and the secondary mirror 20 (primary mirror 10 in FIG. 1) based on the alignment adjustment signal output from the data processing device 44. The mirror 10 and the secondary mirror 20 can be aligned, and as a result, the radar accuracy can be ensured.

  In the laser radar device according to the present embodiment, for example, focusing on a target at a finite distance may be performed by moving the secondary mirror 20 along the optical axis AX. At that time, in the alignment apparatus, the focusing optical system 42 is also moved along its own optical axis so that the spot light formed on the detection surface of the photodetector 43 is sufficiently small. For example, the primary mirror 10 and the secondary mirror 20 can be aligned.

  In the present embodiment, the alignment (alignment) between the primary mirror 10 and the secondary mirror 20 is automatically performed via the attitude control device 50 that operates based on the detection result of the detection system 40. You may go on.

  Thus, in the alignment apparatus according to the present embodiment, the primary mirror 10 and the secondary mirror 20 can be aligned while suppressing the light amount loss while having a simple and low-cost configuration. The first example, which is a specific numerical example of the embodiment, will be described below.

(First embodiment)
Table 1 below lists the values of the specifications of the Cassegrain optical system (see FIG. 2) when the laser radar device is used with respect to an infinite target. In Table 1, the surface number is the order of the surfaces on which the light used by the laser radar device (wavelength 1064 nm) is incident, r is the radius of curvature of each surface (unit: mm, apex radius of curvature in the case of an aspheric surface), d Indicates the on-axis interval of each surface, that is, the surface interval to the next surface (unit: mm), and κ indicates the conic coefficient (conic constant) that defines the aspherical shape of each surface. Note that, in the curvature radius r, the curvature radius of the convex surface toward the light source side is positive, the curvature radius of the concave surface toward the light source side is negative, and “0.0000” indicates a plane. The notation in Table 1 is the same in the following Table 4, Table 7 and Table 10.

  In the aspheric surface, the height in the direction perpendicular to the optical axis is y, and the distance (sag amount) along the optical axis from the tangent plane at the apex of the aspheric surface to the position on the aspheric surface at the height y is z. When the apex radius of curvature is r and the cone coefficient is κ, it is expressed by the following equation (a). Also in the table described later, when the lens surface is an aspheric surface, the surface number is marked with *.

z = (y ² / r) / [1+ {1- (κ + 1) · y ² / r ² } ^1/2 ] (a)

  In the Cassegrain optical system of the first example, the entrance pupil diameter is 40 mm, the center shielding diameter of the used light is 10 mm, and the beam magnification is 8 times.

(Table 1)
Surface number r d κ
1 125.0000 -437.50 (d1) -1 (Reflecting surface 21 of secondary mirror 20)
2 1000.0000 452.50 (d2) -1 (Reflecting surface 11 of primary mirror 10)
3 0.0000 15.00 0 (incident surface 30a of optical member 30)
4 0.0000 ∞ (d3) 0 (Ejection surface 30b of optical member 30)

  Table 2 below lists values of specifications of the alignment optical system (see FIG. 3) of the alignment apparatus applied to the alignment of the Cassegrain optical system in the usage state with respect to the target at infinity. In Table 2, the surface number is the order of the surfaces on which the alignment light is incident, r is the radius of curvature of each surface (unit: mm, apex radius of curvature in the case of an aspheric surface), and d is the axial spacing of each surface, The distance to the next surface (unit: mm), κ is the conic coefficient (conic constant) that defines the aspheric shape of each surface, and n is the refractive index of the alignment light of the medium from each surface to the next surface Respectively.

  Note that, in the curvature radius r, the curvature radius of the convex surface toward the light source side is positive, the curvature radius of the concave surface toward the light source side is negative, and “0.0000” indicates a plane. However, in the condensing optical system 42, the curvature radius r has a negative curvature radius toward the light incident side and a concave curvature radius toward the light incident side. Also, the surface interval d changes its sign each time it is reflected.

  In the alignment optical system of the first example, the entrance pupil diameter is 40 mm, the center shielding diameter of the alignment light is 10 mm, and the wavelength of the alignment light is 632.8 nm. The notation in Table 2 is the same in the following Table 5, Table 8, and Table 11.

(Table 2)
Surface number r d κ
1 125.0000 -437.50 (d1) -1 (Reflecting surface 21 of secondary mirror 20)
2 1000.0000 452.50 (d2) -1 (Reflecting surface 11 of primary mirror 10)
3 0.0000 -452.50 (d4) 0 (incident surface 30a of optical member 30)
4 1000.0000 437.50 (d5) -1 (Reflecting surface 11 of primary mirror 10)
5 125.0000 -537.50 (d6) -1 (Reflecting surface 21 of secondary mirror 20)
6 0.0000 -50.00 (d7) 0 (Beam splitter 41)
7 -59.8164 -10.00 0 1.457021 (Condensing optical system 42)
8 272.6586 -100.00 (d8) 0

  Table 3 below lists the values of the surface spacing in the Cassegrain optical system and alignment optical system for a target at infinity, and the values of the surface spacing in the Cassegrain optical system and alignment optical system for a target at a finite distance (300 m). .

  In Table 3, the surface interval d1 is a distance along the optical axis AX from the reflecting surface 21 of the secondary mirror 20 to the reflecting surface 11 of the primary mirror 10, as shown in Tables 1 and 2. The surface interval d2 is a distance along the optical axis AX from the reflecting surface 11 of the main mirror 10 to the incident surface 30a of the optical member 30, as shown in Tables 1 and 2. As shown in Table 1, the surface interval d3 is a distance from the exit surface 30b of the optical member 30 to the target at infinity. As shown in Table 2, the surface interval d4 is a distance along the optical axis AX from the incident surface 30a of the optical member 30 to the reflecting surface 11 of the primary mirror 10. As shown in Table 2, the surface interval d5 is a distance along the optical axis AX from the reflective surface 11 of the primary mirror 10 to the reflective surface 21 of the secondary mirror 20. The surface interval d6 is a distance along the optical axis AX from the reflecting surface 21 of the secondary mirror 20 to the beam splitter 41 as shown in Table 2. The surface interval d7 is a distance along the optical axis of the condensing optical system 42 from the beam splitter 41 to the incident surface of the condensing optical system 42 as shown in Table 2. The surface interval d8 is a distance along the optical axis of the condensing optical system 42 from the exit surface of the condensing optical system 42 to the detection surface of the photodetector 43 as shown in Table 2.

(Table 3)
Surface distance Infinite distance target Finite distance target
d1 -437.50 -438.36
d2 452.50 453.36
d3 ∞ 300000.00
d4 -452.50 -453.36
d5 437.50 438.36
d6 -537.50 -538.36
d7 -50.00 -55.05
d8 -100.00 -94.95

  From Table 3, in the Cassegrain optical system of the laser radar apparatus according to the first example, the main mirror 10 is moved 300 m from the target at infinity by moving 0.86 mm to the left in FIG. 1 along the optical axis AX. It is possible to perform focusing on a target having a finite distance. At this time, in the alignment optical system of the first embodiment, if focusing is performed by moving the condensing optical system 42 downward along the optical axis by 5.05 mm in FIG. Alignment adjustment (positioning) with 20 is possible.

(Second embodiment)
The second embodiment will be described below. The alignment apparatus of the second embodiment has the same basic configuration as that of the first embodiment. However, the alignment apparatus of the first embodiment is different from the alignment apparatus in that the secondary mirror 20 is movably attached to the housing 60 by the secondary mirror holding spider 22 (not integrated with the optical member 30). The configuration and operation of the alignment apparatus according to the second embodiment will be described by focusing on the fact that the position and orientation of the secondary mirror 20 (not the primary mirror 10) are controlled by the control mechanism 50. In addition, about the thing which has the same function of 1st Example, the same number is attached | subjected and the description may be abbreviate | omitted.

  As shown in FIG. 4, the alignment apparatus of the second embodiment has a light transmission and a secondary mirror 20 that are disposed opposite to each other on the optical axis AX of the primary mirror 10 such as a laser optical apparatus such as a laser radar apparatus. In the optical system capable of receiving light, the primary mirror 10 and the secondary mirror 20 are aligned.

  The primary mirror 10 is a concave mirror having an opening 10a formed on the optical axis AX and a concave reflecting surface 11 formed on the front side (sub mirror 20 side). The secondary mirror 20 is a convex reflecting mirror having a convex reflecting surface 21 that is disposed opposite to the optical axis AX of the primary mirror 10 and formed on the front side (primary mirror 10 side). That is, the primary mirror 10 and the secondary mirror 20 constitute a so-called Cassegrain optical system.

  The optical member 30 has a reflection function and a transmission function with respect to light incident on the member.

  The alignment apparatus is housed in a housing 60 formed with a window 60a through which light transmitted through the optical member 30 can pass, and the optical member 30 is disposed in the window 60a.

  The secondary mirror 20 is attached to the housing 60 by a secondary mirror holding spider 22 so that the position and posture can be adjusted via a posture control mechanism 50 described later.

  The surface shapes of the primary mirror 10, the secondary mirror 20, and the optical member 30 are such that the alignment light incident from the opening 10a of the primary mirror 10 passes through the reflective surface 21 of the secondary mirror 20 and the reflective surface 11 of the primary mirror 10 in order. The incident light path reaching 30 and the alignment light reflected and folded back by the optical member 30 sequentially pass through the reflecting surface 11 of the primary mirror 10 and the reflecting surface 21 of the secondary mirror 20, and then reach the opening 10a of the primary mirror 10. Is set to match.

  Therefore, in the usage state of the laser radar apparatus in the second embodiment, as shown in FIG. 5, when light is transmitted, the laser light supplied from the laser light source (not shown) is reflected by the dichroic mirror M, and the beam splitter. The light passes through 41 and is guided to the Cassegrain optical system (the primary mirror 10 and the secondary mirror 20). The laser light guided to the Cassegrain optical system (primary mirror 10 and secondary mirror 20) is incident from the opening 10a of the primary mirror 10 and sequentially passes through the reflective surface 21 of the secondary mirror 20 and the reflective surface 11 of the primary mirror 10. After passing through the optical member 30, for example, the light is transmitted toward the sky in the target direction in the state of a light beam parallel to the optical axis AX.

  In the case of receiving light, the scattered laser light from the target irradiated with the laser light passes through the optical member 30 and sequentially passes through the reflective surface 11 of the primary mirror 10 and the reflective surface 21 of the secondary mirror 20. 10 passes through the aperture 10a, passes through the beam splitter 41, is reflected by the dichroic mirror M, and then received by a light receiving unit (not shown). The light receiving unit detects the state of the measurement target by detecting the intensity and return time of the received scattered laser light.

  As in the first embodiment, in the alignment apparatus in the second embodiment, the alignment light emitted from the light source L sequentially passes through the dichroic mirror M and the beam splitter 41 as shown in FIG. Is incident in the form of a parallel light beam parallel to the optical axis AX, sequentially passes through the reflecting surface 21 of the secondary mirror 20 and the reflecting surface 11 of the primary mirror 10, and is reflected by the optical member 30 and folded back. After passing through the reflecting surface 11 and the reflecting surface 21 of the secondary mirror 20 in this order, the light exits from the opening 10a of the primary mirror 10 and then enters the beam splitter 41. The alignment light reflected by the beam splitter 41 is condensed on the detection surface of the photodetector 43 via the condensing optical system 42, and the photodetector 43 detects the condensing position of the alignment light on the detection surface. The detection result is output to the data processing device 44. The data processing device 44 calculates the positional deviation between the primary mirror 10 and the secondary mirror 20 by comparing the focusing position of the alignment light detected by the photodetector 43 with a preset reference position. Based on the result, an alignment adjustment signal is generated so that the difference between the focusing position of the alignment light and the reference position is “zero”, and is output to the attitude control mechanism 50. The attitude control mechanism 50 controls the position and attitude of the secondary mirror 20 based on the alignment adjustment signal output from the data processing device 44.

  As described above, even with the alignment apparatus according to the second embodiment, the primary mirror 10 and the secondary mirror 20 can be aligned while suppressing loss of light amount, with a simple and low-cost configuration.

  Table 4 below lists the values of the specifications of the Cassegrain optical system (see FIG. 5) when the laser radar device in the second embodiment is in use with respect to an infinite target. In the Cassegrain optical system of the second embodiment, the entrance pupil diameter is 40 mm, the center shielding diameter of the used light is 10 mm, and the beam expansion magnification is 8 times.

(Table 4)
Surface number r d κ
1 125.0000 -437.50 (d1) -1 (Reflecting surface 21 of secondary mirror 20)
2 1000.0000 497.50 -1 (Reflecting surface 11 of primary mirror 10)
3 0.0000 15.00 0 (incident surface 30a of optical member 30)
4 0.0000 ∞ (d3) 0 (Ejection surface 30b of optical member 30)

  Table 5 below lists values of specifications of the alignment optical system (see FIG. 6) of the alignment apparatus applied to the alignment of the Cassegrain optical system in the use state with respect to the infinity target. In the alignment optical system of the second embodiment, the entrance pupil diameter is 40 mm, the center shielding diameter of the alignment light is 10 mm, and the wavelength of the alignment light is 632.8 nm.

(Table 5)
Surface number r d κ
1 125.0000 -437.50 (d1) -1 (Reflecting surface 21 of secondary mirror 20)
2 1000.0000 497.50 -1 (Reflecting surface 11 of primary mirror 10)
3 0.0000 -497.50 0 (incident surface of optical member 30)
4 1000.0000 437.50 (d5) -1 (Reflecting surface 11 of primary mirror 10)
5 125.0000 -537.50 (d6) -1 (Reflecting surface 21 of secondary mirror 20)
6 0.0000 -50.00 (d7) 0 (Beam splitter 41)
7 -59.8164 -10.00 0 1.457021 (Condensing optical system 42)
8 272.6586 -100.00 (d8) 0

  Table 6 below lists the surface spacing values in the Cassegrain optical system and alignment optical system for a target at infinity, and the surface spacing values in the Cassegrain optical system and alignment optical system for a finite distance (300 m) target. .

  In Table 6, the surface interval d1 is a distance along the optical axis AX from the reflecting surface 21 of the secondary mirror 20 to the reflecting surface 11 of the primary mirror 10, as shown in Tables 4 and 5. As shown in Table 4, the surface interval d3 is a distance from the exit surface 30b of the optical member 30 to the target at infinity. As shown in Table 5, the surface interval d5 is a distance along the optical axis AX from the reflective surface 11 of the primary mirror 10 to the reflective surface 21 of the secondary mirror 20. The surface interval d6 is a distance along the optical axis AX from the reflecting surface 21 of the secondary mirror 20 to the beam splitter 41 as shown in Table 5. The surface interval d7 is a distance along the optical axis of the condensing optical system 42 from the beam splitter 41 to the incident surface of the condensing optical system 42 as shown in Table 5. The surface interval d8 is a distance along the optical axis of the condensing optical system 42 from the exit surface of the condensing optical system 42 to the detection surface of the photodetector 43 as shown in Table 5.

(Table 6)
Surface distance Infinite distance target Finite distance target
d1 -437.50 -438.36
d3 ∞ 300000.00
d5 437.50 438.36
d6 -537.50 -538.36
d7 -50.00 -55.05
d8 -100.00 -94.95

  From Table 6, in the Cassegrain optical system of the laser radar apparatus according to the second example, the secondary mirror 20 is moved 300 m from the target at infinity by moving 0.88 mm along the optical axis AX to the right in FIG. It is possible to perform focusing on a target having a finite distance. At this time, in the alignment optical system of the second embodiment, if focusing is performed by moving the condensing optical system 42 downward along the optical axis by 5.05 mm in FIG. 4, the primary mirror 10 and the secondary mirror Alignment adjustment (positioning) with 20 is possible.

  As described above, in the case of the alignment apparatus according to the second embodiment, focusing adjustment and shift tilt adjustment can be performed by the compact secondary mirror 20 alone, and the weight of the movable parts constituting the attitude control mechanism 50 can be significantly reduced.

(Third embodiment)
The third embodiment will be described below. The alignment apparatus of the third embodiment has the same basic configuration as that of the first embodiment. However, the configuration and operation of the alignment apparatus according to the third embodiment will be described, focusing on the difference from the alignment apparatus according to the first embodiment in that the diameter of the optical member 30 that fixes and holds the secondary mirror 20 is small. In addition, about what has the same function of 1st Example, the same number may be attached | subjected and the description may be abbreviate | omitted.

  As shown in FIG. 7, the alignment apparatus of the third embodiment is a laser optical device such as a laser radar device, and has a sub-mirror 20 disposed opposite to the optical axis AX of the primary mirror 10 and In the optical system capable of receiving light, the primary mirror 10 and the secondary mirror 20 are aligned.

  The primary mirror 10 is a concave mirror having an opening 10a formed on the optical axis AX and a concave reflecting surface 11 formed on the front side (sub mirror 20 side). The secondary mirror 20 is a convex reflecting mirror having a convex reflecting surface 21 that is disposed opposite to the optical axis AX of the primary mirror 10 and formed on the front side (primary mirror 10 side). That is, the primary mirror 10 and the secondary mirror 20 constitute a so-called Cassegrain optical system.

  The optical member 30 is a small plane mirror having a function of reflecting light incident on the member.

  The alignment apparatus is housed in a housing 60 formed with a window 60a through which light emitted from the reflecting surface 11 of the primary mirror 10 can pass.

  The secondary mirror 20 is attached to the housing 60 by the secondary mirror holding spider 22 so that the position and posture of the secondary mirror 20 can be adjusted by a posture control mechanism 50 described later.

  The surface shapes of the primary mirror 10, the secondary mirror 20, and the optical member 30 are such that the alignment light incident from the opening 10a of the primary mirror 10 passes through the reflective surface 21 of the secondary mirror 20 and the reflective surface 11 of the primary mirror 10 in order. The incident light path reaching 30 and the alignment light reflected and folded back by the optical member 30 sequentially pass through the reflecting surface 11 of the primary mirror 10 and the reflecting surface 21 of the secondary mirror 20, and then reach the opening 10a of the primary mirror 10. Is set to match.

  Therefore, in the usage state of the laser radar apparatus in the third embodiment, as shown in FIG. 8, when light is transmitted, the laser light supplied from the laser light source (not shown) is reflected by the dichroic mirror M, and the beam splitter. The light passes through 41 and is guided to the Cassegrain optical system (the primary mirror 10 and the secondary mirror 20). The laser light guided to the Cassegrain optical system (primary mirror 10 and secondary mirror 20) is incident from the opening 10a of the primary mirror 10 and sequentially passes through the reflective surface 21 of the secondary mirror 20 and the reflective surface 11 of the primary mirror 10. For example, light is transmitted toward the sky in the target direction in the state of a light beam parallel to the optical axis AX.

  When receiving light, the scattered laser light from the target irradiated with the laser light passes through the reflective surface 11 of the primary mirror 10 and the reflective surface 21 of the secondary mirror 20 in order, and passes through the opening 10a of the primary mirror 10. After passing through the beam splitter 41 and reflected by the dichroic mirror M, the light is received by a light receiving unit (not shown). The light receiving unit detects the state of the measurement target by detecting the intensity and return time of the received scattered laser light.

  Similar to the first embodiment, according to the alignment apparatus in the third embodiment, as shown in FIG. 9, the alignment light emitted from the light source L sequentially passes through the dichroic mirror M and the beam splitter 41, and It enters in the state of a parallel light beam parallel to the optical axis AX from the opening 10a of the mirror 10, passes through the reflecting surface 21 of the secondary mirror 20 and the reflecting surface 11 of the primary mirror 10 in order, and is reflected by the optical member 30 and folded back. The light passes through the reflective surface 11 of the mirror 10 and the reflective surface 21 of the secondary mirror 20 in order, and is emitted from the opening 10 a of the primary mirror 10 and then enters the beam splitter 41. The alignment light reflected by the beam splitter 41 is condensed on the detection surface of the photodetector 43 via the condensing optical system 42, and the photodetector 43 detects the condensing position of the alignment light on the detection surface. The detection result is output to the data processing device 44. The data processing device 44 calculates the positional deviation between the primary mirror 10 and the secondary mirror 20 by comparing the focusing position of the alignment light detected by the photodetector 43 with a preset reference position. Based on the result, an alignment adjustment signal is generated so that the difference between the focusing position of the alignment light and the reference position is “zero”, and is output to the attitude control mechanism 50. The attitude control mechanism 50 controls the position and attitude of the secondary mirror 20 based on the alignment adjustment signal output from the data processing device 44.

  Thus, even with the alignment apparatus according to the third embodiment, the primary mirror 10 and the secondary mirror 20 can be aligned with a simple and low-cost configuration.

  Table 7 below lists the values of the specifications of the Cassegrain optical system (see FIG. 8) when the laser radar device is used with respect to an infinite target. In the Cassegrain optical system of the third example, the entrance pupil diameter is 40 mm, the center shielding diameter of the used light is 20 mm, and the beam expansion magnification is 8 times.

(Table 7)
Surface number r d κ
1 125.0000 -437.50 (d1) -1 (Reflecting surface 21 of secondary mirror 20)
2 1000.0000 ∞ (d3) -1 (reflection surface 20 of primary mirror 10)

  Table 8 below lists values of specifications of the alignment optical system (see FIG. 9) of the alignment apparatus applied to the alignment of the Cassegrain optical system in the use state with respect to the infinity target. In the alignment optical system of the third example, the entrance pupil diameter is 16 mm, the center shielding diameter of the alignment light is 8.75 mm, and the wavelength of the alignment light is 632.8 nm.

(Table 8)
Surface number r d κ
1 125.0000 -437.50 (d1) -1 (Reflecting surface 21 of secondary mirror 20)
2 1000.0000 452.50 (d2) -1 (Reflecting surface 11 of primary mirror 10)
3 0.0000 -452.50 (d4) 0 (incident surface 30a of optical member 30)
4 1000.0000 437.50 (d5) -1 (Reflecting surface 11 of primary mirror 10)
5 125.0000 -537.50 (d6) -1 (Reflecting surface 21 of secondary mirror 20)
6 0.0000 -50.00 (d7) 0 (Beam splitter 41)
7 -58.4057 -10.00 0 1.457021 (Condensing optical system 42)
8 -270.4231 -100.00 (d8) 0

  Table 9 below shows the values of the surface separation in the Cassegrain optical system and alignment optical system for the target at infinity in the third embodiment, and the surface separation in the Cassegrain optical system and alignment optical system for the target of finite distance (300 m). The value of

  In Table 9, the surface interval d1 is a distance along the optical axis AX from the reflecting surface 21 of the secondary mirror 20 to the reflecting surface 11 of the primary mirror 10, as shown in Tables 7 and 8. As shown in Table 8, the surface interval d2 is a distance along the optical axis AX from the reflecting surface 11 of the main mirror 10 to the incident surface 30a of the optical member 30. As shown in Table 7, the surface interval d3 is a distance from the exit surface 30b of the optical member 30 to the target at infinity. The surface interval d4 is a distance along the optical axis AX from the incident surface 30a of the optical member 30 to the reflecting surface 11 of the primary mirror 10, as shown in Table 8. The surface interval d5 is a distance along the optical axis AX from the reflecting surface 11 of the primary mirror 10 to the reflecting surface 21 of the secondary mirror 20 as shown in Table 8. The surface interval d6 is a distance along the optical axis AX from the reflecting surface 21 of the secondary mirror 20 to the beam splitter 41 as shown in Table 8. As shown in Table 8, the surface distance d7 is a distance along the optical axis of the condensing optical system 42 from the beam splitter 41 to the incident surface of the condensing optical system 42. As shown in Table 8, the surface interval d8 is a distance along the condensing optical system 42 from the exit surface of the condensing optical system 42 to the detection surface of the photodetector 43.

(Table 9)
Surface distance Infinite distance target Finite distance target
d1 -437.50 -438.36
d2 452.50 453.36
d3 ∞ 300000.00
d4 -452.50 -453.36
d5 437.50 438.36
d6 -537.50 -538.36
d7 -50.00 -56.27
d8 -100.00 -93.73

  From Table 9, in the Cassegrain optical system of the laser radar apparatus according to the third example, the secondary mirror 20 is moved 300 m from the target at infinity by moving 0.88 mm along the optical axis AX to the right in FIG. It is possible to perform focusing on a target having a finite distance. At this time, in the alignment optical system of the third embodiment, if focusing is performed by moving the condensing optical system 42 by 6.27 mm along its own optical axis downward in FIG. 7, the primary mirror 10 and the secondary mirror Alignment adjustment (positioning) with 20 is possible.

  As described above, in the case of the alignment apparatus according to the third embodiment, the optical member 30 is a small and simple plane mirror, and can be manufactured at a very low cost. Further, since the plane mirror (which is the optical member 30) is not a large component like the secondary mirror 20, it can be easily joined, and even if it is fixed and held integrally with the secondary mirror 20, there is no heavy burden on the alignment. Driving for adjustment, tilt adjustment, and focusing adjustment can be easily performed.

(Fourth embodiment)
The fourth embodiment will be described below. The alignment apparatus of the fourth embodiment has the same basic configuration as that of the first embodiment. However, unlike the alignment apparatus of the first embodiment, this is applied to a so-called Gregory optical system in which the primary mirror 10 is a concave mirror and the secondary mirror is a concave mirror. In the description of the configuration and operation of the alignment apparatus according to the fourth embodiment, components having the same functions as those of the first embodiment are denoted by the same reference numerals, and the description thereof may be omitted.

  As shown in FIGS. 10 and 11, the alignment apparatus of the fourth embodiment includes a secondary mirror 120 that is disposed opposite to the optical axis AX of the primary mirror 110 in a laser optical apparatus such as a laser radar apparatus. In the optical system capable of transmitting and receiving light, the primary mirror 110 and the secondary mirror 120 are aligned.

  The primary mirror 110 is a concave mirror having an opening 110a formed on the optical axis AX and a concave reflecting surface 111 formed on the front side (sub mirror 120 side). The secondary mirror 120 is a concave reflecting mirror that has a concave reflecting surface 121 that is oppositely disposed on the optical axis AX of the primary mirror 110 and formed on the front side (primary mirror 110 side). That is, the primary mirror 110 and the secondary mirror 120 constitute a so-called Gregory optical system.

  The optical member 30 has a reflection function and a transmission function with respect to light incident on the member.

  The surface shapes of the primary mirror 110, the secondary mirror 120, and the optical member 30 are such that the alignment light incident from the opening 110a of the primary mirror 110 passes through the reflective surface 121 of the secondary mirror 120 and the reflective surface 111 of the primary mirror 110 in order. The incident light path reaching 30 and the alignment light reflected and folded back by the optical member 30 sequentially passes through the reflecting surface 111 of the primary mirror 110 and the reflecting surface 121 of the secondary mirror 120 to reach the opening 110a of the primary mirror 110. Is set to match.

  Therefore, in the usage state of the laser radar apparatus in the fourth embodiment, as shown in FIG. 10, when light is transmitted, the laser light supplied from the laser light source (not shown) is reflected by the dichroic mirror M, and the beam splitter. 41 is transmitted to the Gregory optical system (primary mirror 110, secondary mirror 120). The laser light guided to the Gregory optical system (primary mirror 110, secondary mirror 120) enters from the opening 110a of the primary mirror 110, passes through the reflective surface 121 of the secondary mirror 120 and the reflective surface 111 of the primary mirror 110 in order, After passing through the optical member 30, for example, the light is transmitted toward the sky in the target direction in the state of a light beam parallel to the optical axis AX.

  In the case of receiving light, the scattered laser light from the target irradiated with the laser light passes through the optical member 30 and sequentially passes through the reflective surface 111 of the primary mirror 110 and the reflective surface 121 of the secondary mirror 120, and then the primary mirror. The light passes through the opening 110a of 110, passes through the beam splitter 41, is reflected by the dichroic mirror M, and then received by a light receiving unit (not shown). The light receiving unit detects the state of the measurement target by detecting the intensity and return time of the received scattered laser light.

  As in the first embodiment, according to the alignment apparatus in the fourth embodiment, the alignment light emitted from the light source L sequentially passes through the dichroic mirror M and the beam splitter 41 as shown in FIG. 110 enters in the state of a parallel light beam parallel to the optical axis AX from the opening 110a of 110, passes through the reflecting surface 121 of the secondary mirror 120 and the reflecting surface 111 of the primary mirror 110 in order, is reflected by the optical member 30, and is folded back. After passing through the reflecting surface 111 of 110 and the reflecting surface 121 of the secondary mirror 120 in order, the light exits from the opening 110 a of the primary mirror 110 and then enters the beam splitter 41. The alignment light reflected by the beam splitter 41 is condensed on the detection surface of the photodetector 43 via the condensing optical system 42, and the photodetector 43 detects the condensing position of the alignment light on the detection surface. The detection result is output to the data processing device 44. The data processing device 44 calculates the positional deviation between the primary mirror 110 and the secondary mirror 120 by comparing the focusing position of the alignment light detected by the photodetector 43 with a preset reference position. Based on the result, an alignment adjustment signal is generated so that the difference between the focusing position of the alignment light and the reference position is “zero”, and is output to the attitude control mechanism 50. The attitude control mechanism 50 controls the position and attitude of the secondary mirror 120 based on the alignment adjustment signal output from the data processing device 44.

  As described above, even with the alignment apparatus according to the fourth embodiment, the primary mirror 110 and the secondary mirror 120 can be aligned while suppressing the light loss while having a simple and low-cost configuration.

  Table 10 below lists values of specifications of the Gregory optical system (see FIG. 10) in a use state of the laser radar device with respect to an infinite target. In the Gregory optical system of the fourth example, the entrance pupil diameter is 40 mm, the diameter of the central shield for the used light is 10 mm, and the beam expansion magnification is 8 times.

(Table 10)
Surface number r d κ
1 -125.0000 -562.50 (d11) -1 (Reflecting surface 121 of secondary mirror 120)
2 1000.0000 577.50 (d12) -1 (Reflecting surface 111 of primary mirror 110)
3 0.0000 15.00 0 (incident surface 30a of optical member 30)
4 0.0000 ∞ (d13) 0 (Ejection surface 30b of optical member 30)

  Table 11 below lists values of specifications of the alignment optical system (see FIG. 11) of the alignment apparatus applied to the alignment of the Gregory optical system in the use state with respect to the object at infinity. In the alignment optical system of the fourth example, the entrance pupil diameter is 40 mm, the center shielding diameter of the alignment light is 10 mm, and the wavelength of the alignment light is 632.8 nm.

(Table 11)
Surface number r d κ
1 125.0000 -562.50 (d11) -1 (Reflecting surface 121 of secondary mirror 120)
2 1000.0000 577.50 (d12) -1 (Reflecting surface 111 of primary mirror 110)
3 0.0000 -577.50 (d14) 0 (incident surface 30a of optical member 30)
4 1000.0000 562.50 (d15) -1 (Reflecting surface 111 of primary mirror 110)
5 125.0000 -662.50 (d16) -1 (Reflecting surface 121 of secondary mirror 120)
6 0.0000 -50.00 (d17) 0 (Beam splitter 41)
7 -59.8164 -10.00 0 1.457021 (Condensing optical system 42)
8 272.6586 -100.00 (d18) 0

  Table 12 below lists the surface separation values in the Gregory optical system and the alignment optical system for a target at infinity, and the surface separation values in the Gregory optical system and the alignment optical system for a target at a finite distance (300 m). .

  In Table 12, the surface interval d11 is a distance along the optical axis AX from the reflecting surface 121 of the secondary mirror 120 to the reflecting surface 111 of the primary mirror 110, as shown in Tables 10 and 11. The surface interval d12 is a distance along the optical axis AX from the reflecting surface 111 of the main mirror 110 to the incident surface 30a of the optical member 30 as shown in Table 10 and Table 11. As shown in Table 10, the surface interval d13 is a distance from the exit surface 30b of the optical member 30 to the target at infinity. The surface interval d14 is a distance along the optical axis AX from the incident surface 30a of the optical member 30 to the reflecting surface 111 of the primary mirror 110, as shown in Table 11. The surface interval d15 is a distance along the optical axis AX from the reflective surface 111 of the primary mirror 110 to the reflective surface 121 of the secondary mirror 120, as shown in Table 11. The surface interval d16 is a distance along the optical axis AX from the reflecting surface 121 of the secondary mirror 120 to the beam splitter 41 as shown in Table 11. As shown in Table 11, the surface distance d17 is a distance along the optical axis of the condensing optical system 42 from the beam splitter 41 to the incident surface of the condensing optical system 42. The surface interval d18 is a distance along the optical axis of the condensing optical system 42 from the exit surface of the condensing optical system 42 to the detection surface of the photodetector 43, as shown in Table 11.

(Table 12)
Surface distance Infinite distance target Finite distance target
d9 -562.50 -563.36
d10 577.50 578.36
d11 ∞ 300000.00
d12 -577.50 -578.36
d13 562.50 563.36
d14 -662.50 -663.36
d15 -50.00 -55.03
d16 -100.00 -94.97

  From Table 12, in the Gregory optical system of the laser radar device according to the fourth example, the secondary mirror 20 is moved 300 m from the target at infinity by moving 0.88 mm along the optical axis AX to the right in FIG. It is possible to perform focusing on a target having a finite distance. At this time, in the alignment optical system of the fourth embodiment, if focusing is performed by moving the condensing optical system 42 by 5.03 mm along its own optical axis to the lower side in FIG. Alignment adjustment (positioning) with 20 is possible.

  In addition, in order to make this invention intelligible, although demonstrated with the component requirement of embodiment, it cannot be overemphasized that this invention is not limited to this.

  In the above description, the present invention is applied to a Cassegrain optical system of a laser optical system such as a laser radar apparatus and an alignment apparatus for aligning a primary mirror and a secondary mirror in a Gregory optical system. However, the present invention is not limited to this, and in an optical system having a primary mirror and a secondary mirror that are opposed to each other along the optical axis, the present invention is compared with an alignment device for aligning the primary mirror and the secondary mirror. The invention can be applied.

It is a figure which shows schematically the structure of the alignment apparatus which concerns on 1st Example. It is a figure which shows the use condition of the laser radar apparatus with which the alignment apparatus of 1st Example is applied. It is a figure which shows the state to which the alignment apparatus of 1st Example is applied. It is a figure which shows schematically the structure of the alignment apparatus which concerns on 2nd Example. It is a figure which shows the use condition of the laser radar apparatus with which the alignment apparatus of 2nd Example is applied. It is a figure which shows the state to which the alignment apparatus of 2nd Example is applied. It is a figure which shows schematically the structure of the alignment apparatus which concerns on 3rd Example. It is a figure which shows the use condition of the laser radar apparatus with which the alignment apparatus of 3rd Example is applied. It is a figure which shows the state to which the alignment apparatus of 3rd Example is applied. It is a figure which shows the use condition of the laser radar apparatus with which the alignment apparatus of 4th Example is applied. It is a figure which shows the state to which the alignment apparatus of 4th Example is applied.

Explanation of symbols

10,110 primary mirror
10a, 110a Aperture 11, 111 Reflection surface of primary mirror 20, 120 Secondary mirror 21, 121 Reflection surface of secondary mirror 30 Optical member 40 Detection system 50 Attitude control mechanism 60 Housing 60a Window

Claims (9)

In an optical system having a primary mirror and a secondary mirror arranged so as to face each other along the optical axis, an alignment apparatus for aligning the primary mirror and the secondary mirror,
An optical member having a light reflection function;
A parallel light flux parallel to the optical axis is incident on the secondary mirror, sequentially passes through the reflective surface of the secondary mirror and the reflective surface of the primary mirror, is reflected by the optical member, is folded, and the reflective surface of the primary mirror and Based on alignment light that has passed through the reflecting surface of the secondary mirror in order, a detection system that detects a positional deviation between the primary mirror and the secondary mirror ;
The secondary mirror is fixedly held by the optical member . Surface shapes of the primary mirror, the secondary mirror, and the optical member are as follows:
The alignment light passes through the reflecting surface of the secondary mirror and the reflecting surface of the primary mirror in order, and an incident optical path that reaches the optical member as a parallel light beam,
The alignment light reflected by the optical member and turned back is set so that an exit optical path that sequentially passes through the reflective surface of the primary mirror and the reflective surface of the secondary mirror is matched. 2. The alignment apparatus according to 1. The optical member has a light transmission function,
The alignment device, the alignment device according to claim 1 or 2, characterized in that light transmitted through the optical member is accommodated in a housing in which the window portion is formed can pass through. The alignment apparatus according to claim 3 , wherein the optical member is disposed in the window portion. The detection system is
A beam splitter for dividing the alignment light;
A condensing optical system for condensing the alignment light split by the beam splitter on a predetermined surface;
A detection surface positioned on the predetermined surface, and a light detection means for detecting a focusing position of the alignment light on the detection surface;
Data processing means for calculating a positional deviation between the primary mirror and the secondary mirror by comparing the focusing position of the alignment light detected by the light detection means with a preset reference position. The alignment apparatus according to any one of claims 1 to 4 , wherein: At least a posture control means for controlling the position and posture of at least one of the primary mirror and the secondary mirror so that the optical axes of the primary mirror and the secondary mirror match based on the detection result by the detection system. It has, The alignment apparatus as described in any one of Claims 1-5 characterized by the above-mentioned. The primary mirror is a concave mirror, the secondary mirror alignment apparatus according to any one of claims 1 to 6, characterized in that a convex mirror. The primary mirror is a concave mirror, the secondary mirror alignment apparatus according to any one of claims 1 to 6, characterized in that a concave mirror. Optical device comprising an optical system having a primary mirror and a secondary mirror disposed so as to face each other along the optical axis, to have an alignment device according to any one of claims 1-7.

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