JP6695629B2 - Telecentric optical device - Google Patents

Description

  The present invention relates to a telecentric optical device provided with telecentric lenses on both the object side and the image side.

  In a telecentric optical device in which telecentric lenses are provided on both the object side and the image side, even if the object moves in the optical axis direction (Z direction), the size of the image is changed in the X and Y directions orthogonal to the Z direction. It has the characteristic of not changing. Therefore, it is used as an optical system of a linear scale or an image measuring device, and is widely used for, for example, wide-field collective measurement of an object having a step.

  Patent Document 1 includes a front group having a positive refracting power as a whole and a rear group having a positive refracting power as a whole so that the rear focus of the front group and the front focus of the rear group coincide with each other. And a telecentric optical system in which a diaphragm is arranged at the matching focal position. In these two telecentric optical systems, various aberrations and the telecentricity (degree of telecentricity) of the principal ray of the off-axis light beam are well corrected, so that they are suitably used as an objective lens of an image processing and measuring instrument.

Japanese Patent No. 3708845

  However, in the configuration in which the telecentric lens is provided on both the object side and the image side, and the diaphragm (telecentric diaphragm) is provided at the focal position, the number of components increases and it is necessary to align each part optically with high accuracy. is there. If accurate alignment cannot be performed, there arises a problem that telecentricity is deteriorated or image sharpness is deteriorated.

  An object of the present invention is to provide a telecentric optical device capable of aligning the optical axis with high accuracy while suppressing an increase in the number of parts.

  In order to solve the above-mentioned problems, a telecentric optical device of the present invention includes a first telecentric lens surface provided on the object side and a second telecentric lens surface provided on the image side and having a common focus position with the first telecentric lens surface. Between the lens surface and the first telecentric lens surface and the second telecentric lens surface, it is provided in an outer region outside the light passage region centered on the focal position, and forms the light incident on the outer region. And an optical path changing unit that changes the optical path so as not to contribute to the.

  According to such a configuration, since the optical path changing unit is provided in the outer region that is outside the light passage region around the focus position, the outer region is provided in the outer region without providing a telecentric diaphragm according to the focus position. It is possible to prevent the incident light from contributing to image formation. As a result, it is possible to prevent unwanted light outside the light passage region from being mixed and obtain light with good telecentricity.

  In the telecentric optical device of the present invention, the optical path changing unit may have a refracting surface that refracts the optical path to the outside. Thereby, the light incident on the outer region can be refracted to the outside, and unnecessary light outside the light passage region can be prevented from being mixed.

  In the telecentric optical device of the present invention, the optical path changing portion may have a lens curved surface. Thereby, the light passing through the optical path changing unit is condensed in the optical axis direction of the lens curved surface, and it is possible to prevent unnecessary light outside the light passage region from being mixed.

  In the telecentric optical device of the present invention, the optical path changing unit may have a roughened surface that diffuses the light incident on the outer region. Thereby, the light incident on the outer region can be diffused, and it is possible to prevent unnecessary light outside the light passage region from being mixed.

  The telecentric optical device of the present invention includes a front lens section including a first telecentric lens surface and a rear lens section including a second telecentric lens surface, and the optical path changing section includes at least the front lens section and the rear lens section. It may be provided on one side. Accordingly, the optical path changing unit is provided between the front lens unit and the rear lens unit, and the optical device having the telecentric lens surfaces on both sides can be configured only by combining the two lens units.

  The telecentric optical device of the present invention may further include a fitting portion which is provided between the front lens portion and the rear lens portion and which connects the front lens portion and the rear lens portion by fitting. As a result, the front lens portion and the rear lens portion are positioned by fitting, and the optical axes can be easily and accurately aligned even if they are separate components.

  In the telecentric optical device of the present invention, the fitting portion may have a flat surface provided in the light passage region and orthogonal to the optical axes of the front lens portion and the rear lens portion. As a result, the light passing through the fitting portion travels without being refracted.

  In the telecentric optical device of the present invention, an intermediate region is provided between the front lens unit and the rear lens unit, and the optical path changing unit has a refractive index of a region forming the front lens unit or the rear lens unit, and an intermediate region. The optical path may be refracted according to the difference from the refractive index. As a result, the light passing through the optical path changing unit is refracted to the outside according to the difference in refractive index.

  In the telecentric optical device of the present invention, the light transmittance of the intermediate region may be lower than the light transmittance of the region forming the front lens section or the rear lens section. Thereby, the amount of light passing through the optical path changing unit can be reduced.

  In the telecentric optical device of the present invention, a gap may be provided between the front lens part and the rear lens part in the light passage region. As a result, a minute gap that causes interference fringes does not occur in the light passage region between the front lens unit and the rear lens unit.

  The telecentric optical device of the present invention further includes a positioning mechanism including a reference hole provided in each outer region of the pre-stage lens unit and the post-stage lens unit, and a reference rod inserted into the reference hole. Positioning may be performed in the optical axis direction of the lens unit and the rear lens unit and in a direction orthogonal to the optical axis. As a result, reliable positioning of the front lens unit and the rear lens unit in the optical axis direction and the direction orthogonal to the optical axis is performed.

(A) And (b) is a schematic cross section which illustrates the telecentric optical device which concerns on 1st Embodiment. (A) And (b) is a front view of a front lens part and a back lens part. (A) And (b) is a schematic cross section which illustrates the telecentric optical device which concerns on 2nd Embodiment. (A) And (b) is a schematic cross section which illustrates the telecentric optical device which concerns on 3rd Embodiment. (A)-(c) is a schematic perspective view which illustrates the telecentric optical device which concerns on 4th Embodiment. It is a schematic perspective view which illustrates the telecentric optical device which concerns on 5th Embodiment. (A) And (b) is a schematic cross section which illustrates the telecentric optical device which concerns on 6th Embodiment. It is a schematic perspective view which illustrates the telecentric optical device which concerns on 7th Embodiment. It is a schematic perspective view which illustrates the telecentric optical device which concerns on 7th Embodiment. It is a schematic perspective view which illustrates the telecentric optical device which concerns on 7th Embodiment. It is a schematic diagram which shows an application example. It is a schematic diagram which shows an application example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same members are designated by the same reference numerals, and the description of the members once described is omitted as appropriate.

[First Embodiment]
1A and 1B are schematic cross-sectional views illustrating the telecentric optical device according to the first embodiment.
1A shows an assembled state, and FIG. 1B shows a separated state.
As shown in FIG. 1A, the telecentric optical device 1 according to this embodiment includes a front lens unit 10 arranged on the object side and a rear lens unit 20 arranged on the image side. Each of the front stage lens unit 10 and the rear stage lens unit 20 has a substantially cylindrical shape. A first telecentric lens surface 11 is provided on the object side of the front lens section 10, and a second telecentric lens surface 21 is provided on the image side of the rear lens section 20. The front lens unit 10 and the rear lens unit 20 are connected along the optical axis AX.

  In the telecentric optical device 1, the focal position f1 of the first telecentric lens surface 11 provided on the front lens unit 10 and the focal position f2 of the second telecentric lens surface 21 provided on the rear lens unit 20 coincide with each other. .. Thus, even if the distance to the object changes in the optical axis AX direction, the size of the image does not change in the direction orthogonal to the optical axis AX.

  In the telecentric optical device 1 according to this embodiment, a light passage region TR centered on the focal positions f1 and f2 is provided between the first telecentric lens surface 11 and the second telecentric lens surface 21. The light passage region TR is a region having a predetermined radius centered on the focal positions f1 and f2 on the optical axis AX. Of the light incident from the first telecentric lens surface 11, the light C1 passing through the light passage region TR is emitted from the second telecentric lens surface 21.

  In the telecentric optical device 1, the optical path changing unit 30 is provided in the outer region OR outside the light passage region TR between the first telecentric lens surface 11 and the second telecentric lens surface 21. The optical path changing unit 30 serves to change the optical path so that the light incident on the outer region OR does not contribute to image formation. In this embodiment, the optical path changing unit 30 has a refracting surface 31 that refracts the optical path to the outside.

  Thus, the light C2 emitted from the optical path changing unit 30 out of the light incident from the first telecentric lens surface 11 is refracted to the outside (the side away from the optical axis AX) by the refraction surface 31.

  Here, the shape of the refracting surface 31 may be a lens shape (including a spherical surface, an aspherical surface, a Fresnel lens shape, etc.), a planar shape (including a plane inclined with respect to the optical axis AX), a rough surface shape, etc. Various modes can be adopted as long as the shape can be changed.

  In the telecentric optical device 1, an intermediate region 15 is provided between the front lens unit 10 and the rear lens unit 20, that is, between the refracting surface 31 and the rear lens unit 20. In the example shown in FIG. 1A, the intermediate region 15 has a space. Since the space is provided, the optical path is refracted according to the difference in the refractive index of light between the refracting surface 31 and the space.

  In this way, the optical path is refracted outward due to the shape of the refracting surface 31 and the refractive index difference between the refracting surface 31 and the intermediate region 15, so that the optical path changing portion 30 of the light incident from the first telecentric lens surface 11 is reflected. The light C2 heading for is refracted away from the optical axis AX, and only the light C1 heading for the light passage region TR is emitted from the second telecentric lens surface 21.

  In the telecentric optical device 1, a fitting section 40 is provided between the front lens section 10 and the rear lens section 20. As shown in FIG. 1B, the fitting portion 40 is a portion where the concave portion 45 and the convex portion 46 fit together. The concave portion 45 is provided in the front lens portion 10, and the convex portion 46 is provided in the rear lens portion 20. The concave portion 45 may be provided in the rear lens portion 20, and the convex portion 46 may be provided in the front lens portion 10.

  By fitting the concave portion 45 and the convex portion 46, the front lens unit 10 and the rear lens unit 20 are aligned with each other. The position of the fitting portion 40 corresponds to the position of the light passage region TR in the telecentric optical device 1. Planes 45a and 46a are provided at the portions where the concave portion 45 and the convex portion 46 are fitted and contact each other. The planes 45a and 46a are planes orthogonal to the optical axis AX. The flat surface 45a is the bottom surface of the concave portion 45, and the flat surface 46a is the protruding surface of the convex portion 46. The concave portion 45 and the convex portion 46 are fitted to a position where the flat surfaces 45a and 46a contact each other.

2A and 2B are front views of the front lens unit and the rear lens unit.
FIG. 2A shows a front view of the front lens section 10 as seen from the recess 45 side along the optical axis AX, and FIG. 2B shows the rear lens section 20 as a convex portion along the optical axis AX. The front view seen from the 46 side is shown.
As shown in FIG. 2A, a recess 45 is provided at the center of the front lens unit 10. The recess 45 has an inner diameter D1. The refraction surface 31 of the optical path changing unit 30 is provided around the recess 45.

  As shown in FIG. 2B, a convex portion 46 is provided at the center of the rear lens unit 20. The convex portion 46 has an outer diameter D2. The outer diameter D2 of the convex portion 46 and the inner diameter D1 of the concave portion 45 are provided in such fitting dimensions that the mutual alignment of the convex portion 46 and the concave portion 45 is fixed.

  The front lens part 10 and the rear lens part 20 are molded by, for example, a glass mold or a plastic mold. Since the concave portion 45 of the front lens portion 10 and the convex portion 46 of the rear lens portion 20 are manufactured by molding, they are combined by fitting to form the front lens portion 10 and the rear lens portion based on the optical axis AX. Accurate alignment of 20 can be easily performed.

  According to the telecentric optical device 1 having such a configuration, since the optical path changing unit 30 is provided in the outer region OR which is outside the light passage region TR centered on the focal positions f1 and f2, the focal position is reduced. It is possible to refract light outside the light passage region TR to the outside of the optical path without providing a telecentric diaphragm in accordance with f1 and f2. That is, by simply connecting the front lens unit 10 and the rear lens unit 20 by fitting, unnecessary light outside the light passage region TR can be removed without providing a telecentric diaphragm, and light with good telecentricity can be obtained. You can

[Second Embodiment]
3A and 3B are schematic cross-sectional views illustrating the telecentric optical device according to the second embodiment.
In the telecentric optical device 1B shown in FIG. 3A, the optical path changing unit 30 is provided with a roughened surface (rough surface 32). The rough surface 32 is a surface facing the rear lens unit 20 of the optical path changing unit 30, and diffuses the light C2 incident on the optical path changing unit 30. As a result, it is possible to prevent unnecessary light outside the light passage region TR from entering the rear lens unit 20.
In the illustration of FIG. 3A, the rough surface 32 has a roughened surface orthogonal to the optical axis AX, and refracts the light C2 in various directions depending on the incident position. Therefore, unlike the above-described refracting surface 31, the optical path is not made to be refracted only to the outside, but the refracting surface 31 itself for refracting the optical path to the outside may be roughened.

In the telecentric optical device 1C shown in FIG. 3B, the embedding section 50 is provided between the front lens section 10 and the rear lens section 20. In the embedding portion 50, a material having a light transmittance lower than that of the front lens portion 10 (low transmittance material) is embedded in the intermediate region 15. By embedding a material having a very low light transmittance, the embedding portion 50 becomes a light shielding film. As a result, the amount of light passing through the optical path changing unit 30 is reduced, and it is possible to prevent unnecessary light outside the light passage region TR from entering the rear lens unit 20.
In FIG. 3B, the boundary surface 33 between the optical path changing portion 30 and the embedding portion 50 is represented by a straight line (flat surface), but it may be a refracting surface 31 or a rough surface 32.

[Third Embodiment]
4A and 4B are schematic cross-sectional views illustrating the telecentric optical device according to the third embodiment.
The telecentric optical devices 1D and 1E according to the third embodiment have a configuration in which the front lens unit 10 and the rear lens unit 20 are integrated.
In the telecentric optical device 1D shown in FIG. 4A, an optical path changing unit 30 is provided between the integrated front lens unit 10 and rear lens unit 20. The surface of the optical path changing unit 30 on the front lens unit 10 side is roughened. Furthermore, the surface of the optical path changing unit 30 on the rear lens unit 20 side is also roughened.

  To manufacture the telecentric optical device 1D, a substantially cylindrical member having the first telecentric lens surface 11 on one end side and the second telecentric lens surface 21 on the other end side is formed by glass molding or plastic molding, Make a notch in the outer periphery of the center of this member. By making this notch, the intermediate region 15 of the space is formed and the optical path changing portion 30 is formed. The both surfaces of the optical path changing unit 30 are roughened by the roughness of the surface of the blade used for making the notches.

  In the telecentric optical device 1E shown in FIG. 4B, the embedding part 50 is provided between the integrated front stage lens part 10 and rear stage lens part 20. In the embedding portion 50, a material having a light transmittance lower than that of the front lens portion 10 (low transmittance material) is embedded in the intermediate region 15. As a result, the amount of light passing through the optical path changing unit 30 is reduced.

  To manufacture the telecentric optical device 1E, a substantially cylindrical member having a first telecentric lens surface 11 on one end side and a second telecentric lens surface 21 on the other end side is formed by glass molding or plastic molding, A cut is made halfway around the outer periphery of the central part of this member. By making this notch, the intermediate region 15 of the space is formed. Then, the embedded portion 50 is formed by embedding a low transmittance material in the intermediate region 15.

  In any of the telecentric optical devices 1D and 1E shown in FIGS. 4A and 4B, since the front lens unit 10 and the rear lens unit 20 are integrated, it is not necessary to align the optical axes of the both. Moreover, the number of parts can be reduced.

[Fourth Embodiment]
5A to 5C are schematic perspective views illustrating the telecentric optical device according to the fourth embodiment.
The telecentric optical device 1F according to this embodiment is a lenticular type in which a plurality of lens units are arranged. In the telecentric optical device 1F, four cylindrical lenses are arranged side by side.

  The front lens portion 10 is provided with four first telecentric lens surfaces 11 corresponding to the four cylindrical lenses, and the rear lens portion 20 is provided with four second telecentric lens surfaces 21 corresponding to the four cylindrical lenses. Be done.

5A to 5C, the manufacturing method of the telecentric optical device 1F is shown in order.
First, as shown in FIG. 5A, the front lens unit 10 and the rear lens unit 20 are formed by glass molding or plastic molding, respectively. Convex portions 12 and 22 extending in the lens longitudinal direction are provided at portions of the front lens portion 10 and the rear lens portion 20 corresponding to the respective cylindrical lenses.

  Next, as shown in FIG. 5B, the front lens portion 10 and the rear lens portion 20 are superposed so that the convex portions 12 and 22 of the rear lens portion 20 abut against each other. The front-stage lens unit 10 and the rear-stage lens unit 20 may be fixed with an adhesive or fixed by a holding unit (not shown). The mutual alignment of the front-stage lens unit 10 and the rear-stage lens unit 20 can be determined by the positional relationship between the convex portions 12 and 22. It should be noted that the alignment may be performed by a mark or unevenness (not shown).

  Since the convex portions 12 and 22 of the front lens unit 10 and the rear lens unit 20 are abutted against each other, a gap of the intermediate region 15 is generated between the front lens unit 10 and the rear lens unit 20.

  Next, as shown in FIG. 5C, a low transmittance material is embedded in the gap of the intermediate region 15 to form the embedded portion 50. As a result, the telecentric optical device 1F is completed.

  Even in such a lenticular type telecentric optical device 1F, an optical device having a good telecentricity can be provided with a simple configuration without providing a telecentric diaphragm.

  It should be noted that the front lens part 10 and the rear lens part 20 shown in FIGS. 5A to 5C have been described by way of example in which the convex parts 12 and 22 are provided. The front stage lens unit 10 and the rear stage lens unit 20 may be fitted to each other by the fitting unit 40 according to.

[Fifth Embodiment]
FIG. 6 is a schematic perspective view illustrating the telecentric optical device according to the fifth embodiment.
As shown in FIG. 6, the telecentric optical device 1G according to the fifth embodiment is a lenticular type in which a plurality of lens units are arranged. In the telecentric optical device 1G, four cylindrical lenses are arranged side by side.

  In the telecentric optical device 1G, the light absorbing portion 51 is provided between the plurality of first telecentric lens surfaces 11 and between the plurality of second telecentric lens surfaces 21. The refracting surface 31 provided on each of the plurality of optical path changing portions 30 is a lens surface, and the light passing through the refracting surface 31 is focused on the light absorbing portion 51. With such a configuration, the light whose path has been changed by each optical path changing unit 30 is absorbed by the light absorbing unit 51, and as a result, does not re-enter the adjacent second telecentric lens surface 21.

[Sixth Embodiment]
7A and 7B are schematic cross-sectional views illustrating the telecentric optical device according to the sixth embodiment.
7A shows the assembled state, and FIG. 7B shows the separated state.
In the telecentric optical device 1H, as the fitting part 40 provided between the front lens part 10 and the rear lens part 20, the concave parts 451/452 and the convex parts 461/462 are provided in the front lens part 10 and the rear lens part 20, respectively. It is provided.

  The recess 451 provided in the front lens unit 10 and the recess 452 provided in the rear lens unit 20 have the same shape and the same size. Further, the convex portion 461 provided on the front lens portion 10 and the convex portion 462 provided on the rear lens portion 20 have the same shape and the same size. That is, the front lens section 10 and the rear lens section 20 have the same shape. When the front lens unit 10 and the rear lens unit 20 are fitted together, one of them is rotated about the optical axis AX by 180 degrees with respect to the other so that the concave portion 451 and the convex portion 462 and the concave portion 452 and the convex portion 461 face each other. Fit together. This constitutes the telecentric optical device 1H.

  In the telecentric optical device 1H according to the present embodiment, since the front lens part 10 and the rear lens part 20 have the same shape, the front lens part 10 and the rear lens part 20 can be formed by one mold.

[Seventh Embodiment]
8 to 10 are schematic cross-sectional views illustrating the telecentric optical device according to the seventh embodiment.
The telecentric optical devices 1I, 1J, and 1K according to the seventh embodiment have a configuration in which the front lens unit 10 and the rear lens unit 20 are combined without using the fitting unit 40.

  Here, when the front lens portion 10 having the concave portion 45 and the rear lens portion 20 having the convex portion 46 are molded, the flat surface 45a of the concave portion 45 and the flat surface 46a of the convex portion 46 do not become perfect flat surfaces, and In some cases, minute irregularities of different shapes are formed on each surface. When the flat surfaces 45a and 46a come into contact with each other, a minute gap is formed on the contact surface. Further, since the contact surface is also the light passage region TR, when the light C1 passes therethrough, interference fringes may be generated due to the minute gap, and the light intensity of the light C1 may be attenuated. Therefore, in the telecentric optical devices 1I, 1J, and 1K shown in FIGS. 8 to 10, the front lens unit 10 and the rear lens unit 20 are combined without using the fitting unit 40.

  The telecentric optical device 1I shown in FIG. 8 has a configuration in which the fitting portion 40 of the telecentric optical device 1 shown in FIGS. 1A and 1B is not provided. The telecentric optical device 1J shown in FIG. 9 has a configuration in which the fitting portion 40 of the telecentric optical device 1B shown in FIG. 3A is not provided. The telecentric optical device 1K shown in FIG. 10 has a structure in which the rear lens portion 20 of the telecentric optical device 1J shown in FIG.

  In these telecentric optical devices 1I, 1J, and 1K, the following positioning mechanism is used to combine the front lens unit 10 and the rear lens unit 20 regardless of the fitting unit 40. That is, the reference hole α1 is provided further outside the outer region OR of the front lens unit 10, the reference hole α2 is provided further outside the outer region OR of the rear lens unit 20, and the reference rods are provided in the reference holes α1 and α2. Insert β. This constitutes a positioning mechanism for the front lens unit 10 and the rear lens unit 20. By this positioning mechanism, the pre-stage lens unit 10 and the post-stage lens unit 20 are positioned in the direction along the optical axis AX and the direction orthogonal to the optical axis AX, and the pre-stage lens unit 10 and the post-stage lens in the light passage region TR are formed. A constant gap is provided between the part 20 and the part 20.

  A portion P thicker than the reference holes α1 and α2 is provided in the middle of the reference rod β. The thickness of this portion P determines the distance between the front lens unit 10 and the rear lens unit 20 (positioning in the optical axis AX direction). The thickness of this portion P is determined so that the focal positions of the front lens unit 10 and the rear lens unit 20 coincide with each other.

  According to such a positioning mechanism, a minute gap that causes an interference fringe is not generated in the light passage region TR between the front lens unit 10 and the rear lens unit 20, and it is provided in the outer region OR. Unnecessary light can be excluded by the refracting surface 31 of the optical path changing unit 30.

[Application example]
11 and 12 are schematic diagrams showing application examples.
11 and 12 show an example in which the telecentric optical device 1 according to the present embodiment is applied to the linear scale 100. As shown in FIG. 11, the linear scale 100 includes a detection unit 110 and a scale 120. The scale 120 includes a plurality of measurement grids 121 arranged along the measurement reference line ML. The measurement grid 121 is, for example, a slit. The control unit 130 is connected to the detection unit 110. The linear scale 100 detects the relative positional relationship between the detection unit 110 and the scale 120 along the measurement reference line ML. The signal captured by the detection unit 110 is sent to the control unit 130, and the position of the detection unit 110 with respect to the measurement reference line ML is calculated.

  FIG. 12 shows the structure of the detection unit 110. The detection unit 110 is provided with the light receiving section 112 and the telecentric optical device 1 according to this embodiment. In the linear scale 100, the light emitted from the light emitting unit 111 is transmitted through the measurement grating 121 by the light receiving unit 112 via the telecentric optical device 1, and the displacement amount is measured by detecting the change in the amount of received light.

  By using the telecentric optical device 1 according to this embodiment as the optical system of the detection unit 110 of such a linear scale 100, the configuration of the optical system of the detection unit 110 can be simplified, and good telecentricity can improve accuracy. It is possible to make high measurements.

  As described above, according to this embodiment, it is possible to provide a telecentric optical device capable of aligning the optical axis with high accuracy while suppressing an increase in the number of parts.

  Although the present embodiment has been described above, the present invention is not limited to these examples. For example, although the example in which the optical path changing unit 30 is provided in the pre-stage lens unit 10 has been shown above, the optical path changing unit 30 may be provided in the post-stage lens unit 20, or the pre-stage lens unit 10 and the post-stage lens unit. 20 may be provided in both. Further, those skilled in the art appropriately added, deleted, and changed the design of each of the above-described embodiments, and those obtained by appropriately combining the features of the respective embodiments have the gist of the present invention. As long as it is present, it is included in the scope of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used as an optical system of a linear scale, another measuring device such as an image measuring device, and an optical device such as a microscope.

1, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I, 1J, 1K ... Telecentric optical device 10 ... Pre-stage lens unit 11 ... First telecentric lens surface 12 ... Convex portion 15 ... Intermediate region 20 ... Post-stage lens Part 21 ... Second telecentric lens surface 30 ... Optical path changing part 31 ... Refractive surface 32 ... Rough surface 33 ... Boundary surface 40 ... Fitting part 45 ... Recesses 45a, 46a ... Flat surface 46 ... Convex part 50 ... Embedding part 51 ... Light absorption Part 100 ... Linear scale 110 ... Detection unit 111 ... Light emitting part 112 ... Light receiving part 120 ... Scale 121 ... Measurement grating 130 ... Control part 451 ... Recessed part 452 ... Recessed part 461 ... Convex part 462 ... Convex part AX ... Optical axis OR ... Outer region TR ... Light passing area C1, C2 ... Light f1, f2 ... Focus position

Claims (11)

A first telecentric lens surface provided on the object side,
A second telecentric lens surface which is provided on the image side and has a focal point common to the first telecentric lens surface;
Between the first telecentric lens surface and the second telecentric lens surface, it is provided in an outer region outside the light passage region centered on the focal point position, and forms light incident on the outer region. An optical path changing unit that changes the optical path so that it does not contribute to
A plurality of lens parts having
A telecentric optical device in which a plurality of the lens portions are arranged in one direction to form an integral lenticular lens .   The telecentric optical device according to claim 1, wherein the optical path changing unit has a refracting surface that refracts the optical path to the outside.   The telecentric optical device according to claim 2, wherein the refracting surface has a curved lens surface.   2. The telecentric optical device according to claim 1, wherein the optical path changing unit has a roughened surface that diffuses the light incident on the outer region. A front lens portion including the first telecentric lens surface;
A rear lens section including the second telecentric lens surface,
The telecentric optical device according to any one of claims 1 to 4, wherein the optical path changing unit is provided in at least one of the front lens unit and the rear lens unit.   The telecentric according to claim 5, further comprising a fitting portion provided between the front lens portion and the rear lens portion, the fitting portion connecting the front lens portion and the rear lens portion by fitting. Optical device.   7. The telecentric optical device according to claim 6, wherein the fitting portion has a plane that is provided in the light passage region and is orthogonal to the optical axes of the front lens portion and the rear lens portion. An intermediate region is provided between the front lens unit and the rear lens unit,
The optical path changing unit refracts the optical path according to a difference between a refractive index of a region forming the front lens unit or the rear lens unit and a refractive index of the intermediate region. 7. The telecentric optical device according to any one of items 7.   9. The telecentric optical device according to claim 8, wherein the light transmittance of the intermediate region is lower than the light transmittance of a region forming the front lens unit or the rear lens unit.   The telecentric optical device according to claim 5, wherein a gap is provided between the front lens unit and the rear lens unit in the light passage region. Further comprising a positioning mechanism including a reference hole provided in each of the outer regions of the front lens portion and the rear lens portion, and a reference rod inserted into the reference hole,
The telecentric optical device according to claim 10, wherein the positioning mechanism positions the front-stage lens unit and the rear-stage lens unit in an optical axis direction and a direction orthogonal to the optical axis.

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