Optical device and manufacturing method thereof

Abstract

To improve optical performance by realizing a precise focus adjustment.SOLUTION: An optical device includes an assembled lens including multiple lenses and a sleeve 225, and a cylindrical holder 210. By providing a groove-shaped or slit-shaped deficient section 212a along an axial direction of the holder 210 on an inner surface 212 of the holder 210, a pair of corner sections 214 is provided along the axial direction. The pair of corner sections 214 functions as a guide when positioning the assembled lens relative to the holder 210 in the axial direction by allowing the assembled lens to slide along the axial direction in the holder 210 in a state in which an outer peripheral surface 225a of the sleeve 225 is in contact with the pair of corner sections 214 when inserting the assembled lens into the holder 210.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present disclosure relates to optical instruments and methods for manufacturing same. [Background technology]

[0002] Optical devices such as cameras and projectors are provided with various optical lenses depending on their applications. There are various known assembly structures for assembling these optical lenses to a housing, one of which is an assembly structure in which a lens assembly made up of multiple optical lenses and a sleeve for holding the lenses is held by a cylindrical holder.

[0003] In the manufacture of an optical device employing the above-mentioned assembly structure, first, a lens assembly is prepared by assembling the above-mentioned multiple optical lenses and sleeves together, and then this lens assembly is fixed in a state where it is inserted into a holder.

[0004] When the compound lens is fixed to the holder, the focus is adjusted by aligning the reference surface of the compound lens with the reference surface of the imaging element, such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor, which is pre-assembled in the holder, to the order of a few μm. Highly accurate focus adjustment is extremely important for improving the performance of optical equipment.

[0005] For example, JP 5-196849 A (Patent Document 1) discloses an optical device in which a portion of the inner surface of the holder is configured in an approximately V-shape and the peripheral surface of the lens is abutted against a pair of inclined surfaces of that portion to position the lens radially, thereby enabling high-precision focus adjustment. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 5-196849 Summary of the Invention [Problem to be solved by the invention]

[0007] Here, in order to achieve high-precision focus adjustment, it is important not only to improve the positioning accuracy of the compound lens in the radial direction described above, but also to improve the positioning accuracy of the compound lens in the axial direction of the holder.

[0008] Therefore, an object of the present disclosure is to improve optical performance by achieving high-precision focus adjustment in an optical device comprising a lens assembly and a cylindrical holder for holding the assembly, and to make it possible to manufacture such an optical device. [Means for solving the problem]

[0009] The optical device according to the present disclosure includes a lens assembly including a plurality of lenses and a sleeve for holding the plurality of lenses, and a cylindrical holder for holding the lens assembly. The lenses are aligned along the axial direction of the sleeve and are fixed in a state of being inserted into the sleeve such that the optical axes of the lenses are aligned with the axis of the sleeve. The lens assembly is fixed in a state of being inserted into the holder such that the sleeve is disposed coaxially with the holder. A groove- or slit-shaped cutout portion extending along the axial direction of the holder is provided on the inner surface of the holder, so that a pair of corners positioned to sandwich the cutout portion are provided on the inner surface of the holder so as to extend along the axial direction of the holder. In the optical device according to the present disclosure, when the lens group is inserted into the holder, the outer peripheral surface of the sleeve abuts against the pair of corners and the lens group slides within the holder along the axial direction of the holder, so that the pair of corners function as guides for positioning the lens group relative to the holder in the axial direction of the holder.

[0010] In this way, by configuring the pair of corners to function as guides when positioning the lens assembly relative to the holder in the axial direction of the holder, high-precision focus adjustment can be achieved, thereby improving optical performance.

[0011] In the optical device according to the present disclosure, an elastic biasing member protruding toward the pair of corners may be provided on the inner surface of the holder. In this case, when the lens assembly is inserted into the holder, the lens assembly may be elastically biased toward the pair of corners by the elastic biasing member, so that the outer circumferential surface of the sleeve abuts against the pair of corners.

[0012] With this configuration, when the lens assembly is inserted into the holder, the lens assembly can be temporarily fixed in the axial and radial directions of the holder, which effectively prevents the lens assembly, which has been focus-adjusted with high accuracy, from shifting position before being fixed to the holder, thereby preventing the accuracy of the focus adjustment from decreasing.

[0013] In the optical device according to the present disclosure, a rotation prevention recess may be provided on the outer circumferential surface of the sleeve, in which case, when the lens assembly is inserted into the holder, the elastic biasing member may come into contact with the rotation prevention recess to prevent the lens assembly from rotating relative to the holder.

[0014] With this configuration, the lens assembly can be positioned with high precision relative to the holder in the rotation direction.

[0015] In the optical device according to the present disclosure, a fixing member protruding toward the pair of corners may be provided on the inner surface of the holder. In this case, the lens assembly may be pressed toward the pair of corners by the fixing member, so that the lens assembly is sandwiched and fixed between the fixing member and the pair of corners.

[0016] With this configuration, the lens assembly, which has been subjected to highly accurate focus adjustment, can be fixed to the holder so as not to move in both the axial and radial directions of the holder, thereby providing an optical device with highly accurate focus adjustment.

[0017] In the optical device according to the present disclosure, the fixing member may be configured by a fixing screw.

[0018] With this configuration, the lens assembly can be fixed to the holder with a simple configuration.

[0019] In the optical instrument according to the present disclosure, a tip of the fixing screw may have a substantially planar shape.

[0020] This configuration can disperse the stress applied to the outer peripheral surface of the sleeve when the fixing screw presses the sleeve, thereby reducing the residual stress present in the outer peripheral surface of the sleeve after fixing, thereby preventing the lens assembly from shifting position over time.

[0021] In the optical device according to the present disclosure, the outer circumferential surface of the sleeve in a portion that abuts against the fixing screw may have a substantially planar shape.

[0022] With this configuration, it is possible to disperse the stress applied to the outer circumferential surface of the sleeve when the sleeve is pressed by the fixing screw, thereby making it possible to suppress the occurrence of positional shifting of the compound lens over time.

[0023] In the optical device according to the present disclosure, the sleeve is preferably cylindrical, and in that case, the distance between the pair of corners is preferably equal to or less than half the outer diameter of the sleeve.

[0024] With this configuration, the compound lens including the sleeve can be stably slid along its axial direction within the holder, and the compound lens can be firmly fixed to the holder.

[0025] In the optical device according to the present disclosure, the holder may be made of metal. Such a configuration improves the workability of the holder, making it possible to easily provide the cutout portion therein.

[0026] A manufacturing method of an optical device according to the present disclosure includes a step of preparing a lens assembly including a plurality of lenses and a sleeve for holding the plurality of lenses, a step of preparing a cylindrical holder, and a step of inserting the lens assembly into the holder. In the step of preparing the lens assembly, the lenses are arranged along the axial direction of the sleeve and are fixed in a state of being inserted into the sleeve such that the optical axes of the lenses are aligned along the axial line of the sleeve. In the step of preparing the holder, a groove-like or slit-like cutout portion extending along the axial direction of the holder is provided on the inner surface of the holder, so that a pair of corners positioned to sandwich the cutout portion are provided on the inner surface of the holder so as to extend along the axial direction of the holder. In the step of inserting the lens assembly into the holder, the lens assembly slides within the holder along the axial direction of the holder with the outer peripheral surface of the sleeve abutting against the pair of corners, thereby positioning the lens assembly relative to the holder in the axial direction of the holder.

[0027] With this configuration, the pair of corners function as guides when positioning the lens assembly relative to the holder in the axial direction of the holder, thereby enabling highly accurate focus adjustment and improving optical performance.

[0028] In the manufacturing method of the optical device according to the present disclosure, in the step of preparing the holder, an elastic biasing member protruding toward the pair of corners may be provided on the inner surface of the holder. In that case, in the step of inserting the lens assembly into the holder, the lens assembly may be elastically biased toward the pair of corners by the elastic biasing member, so that the outer circumferential surface of the sleeve abuts against the pair of corners.

[0029] With this configuration, when the lens assembly is inserted into the holder, the lens assembly can be temporarily fixed in the axial and radial directions of the holder, which effectively prevents the lens assembly, which has been focus-adjusted with high accuracy, from shifting position before being fixed to the holder, thereby preventing the accuracy of the focus adjustment from decreasing.

[0030] The manufacturing method of the optical device according to the present disclosure may further include a step of fixing the lens assembly to the holder. In that case, in the step of preparing the holder, a fixing member protruding toward the pair of corners may be provided on the inner surface of the holder. In that case, in the step of fixing the lens assembly to the holder, the lens assembly in a state where it has been positioned relative to the holder may be pressed toward the pair of corners by the fixing member, so that the lens assembly is sandwiched and fixed between the fixing member and the pair of corners.

[0031] With this configuration, the lens assembly, which has been subjected to highly accurate focus adjustment, can be fixed to the holder so as not to move in both the axial and radial directions of the holder, thereby providing an optical device with highly accurate focus adjustment. Effect of the Invention

[0032] According to the present invention, in an optical device comprising a lens assembly and a cylindrical holder for holding the assembly, it is possible to improve the optical performance by achieving high-precision focus adjustment, and also to make it possible to manufacture such an optical device. [Brief description of the drawings]

[0033] [Figure 1] 1 is a schematic diagram of a three-dimensional measuring apparatus according to an embodiment; [Diagram 2] 2 is a schematic diagram showing a functional block configuration of the measurement head shown in FIG. 1. [Diagram 3] 2 is a schematic diagram showing a concept of a specific structure of the measurement head shown in FIG. 1. [Figure 4] FIG. 2 is a schematic perspective view showing the external structure of the measurement head shown in FIG. [Diagram 5] FIG. 2 is a schematic perspective view showing the internal structure of the measurement head shown in FIG. [Figure 6] FIG. 6 is a schematic plan view of the measurement head shown in FIG. 5. [Figure 7] 7 is a schematic cross-sectional view of the projection unit shown in FIG. 6. [Figure 8] 7 is a schematic cross-sectional view of the projection unit shown in FIG. 6. [Figure 9] FIG. 7 is a schematic cross-sectional view of the imaging section shown in FIG. [Figure 10] FIG. 7 is a schematic cross-sectional view of the imaging section shown in FIG. [Figure 11] 6 is an enlarged perspective view of a main part of a holder for a projection unit and a holder for an imaging unit shown in FIG. 5. [Figure 12] 6 is an exploded perspective view showing an assembly structure of the measuring head shown in FIG. 5. [Figure 13] 5 is a schematic cross-sectional view for explaining a stress applied to a sleeve. FIG. [Figure 14] 6A to 6C are schematic cross-sectional views for explaining an assembly procedure of the internal structure of the measurement head shown in FIG. 5. [Figure 15] 6A to 6C are schematic cross-sectional views for explaining an assembly procedure of the internal structure of the measurement head shown in FIG. 5. [Figure 16]It is a schematic cross-sectional view for explaining the assembly procedure of the internal structure of the measurement head shown in FIG. 5. [Figure 17] It is a schematic perspective view showing the external structure of the measurement head according to the modified example. [Figure 18] It is a schematic cross-sectional view of the projection part shown in FIG. 17.

Mode for Carrying Out the Invention

[0034] Hereinafter, embodiments will be described in detail with reference to the drawings. In the embodiments shown below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

[0035] <A. Three-Dimensional Measuring Device> FIG. 1 is a schematic view of a three-dimensional measuring device according to an embodiment. First, with reference to FIG. 1, the three-dimensional measuring device 1 according to the present embodiment will be described.

[0036] As shown in FIG. 1, the three-dimensional measuring device 1 includes a measurement head 10 and an image measuring device 1000. The image measuring device 1000 is also referred to as a sensor controller or a vision sensor.

[0037] The image measuring device 1000 acquires an image (hereinafter, also referred to as an "input image") of the subject imaged by the measurement head 10 in a state where a predetermined projection pattern from the measurement head 10 is projected onto the subject as the measurement object. Typically, as the projection pattern, a projection pattern conforming to structured illumination is adopted. That is, as the projection pattern, a pattern in which a plurality of types of reference patterns each assigned a unique code are arranged according to a predetermined rule is adopted (this type of method is referred to as the unique code method).

[0038] The image measuring device 1000 executes three-dimensional measurement processing using the information of the projection pattern and the information of the projection pattern appearing in the acquired input image, thereby acquiring a three-dimensional measurement result (three-dimensional measurement result image).

[0039] More specifically, the image measurement device 1000 searches for each reference pattern (hereinafter also referred to as "primitive") included in the projected projection pattern within the input image. As a result, the image measurement device 1000 acquires the position irradiated with each primitive and the set of codes indicated by the irradiated primitive. Then, the image measurement device 1000 searches for a corresponding region (hereinafter also referred to as "lattice code pattern") that shows the same array as the array of codes indicated by a predetermined number of reference patterns included in a unit region (hereinafter also referred to as "word") set in the projection pattern from the set of these codes. Finally, the image measurement device 1000 calculates the distances from the irradiation reference plane of the projection pattern to each part of the subject based on the search result of the lattice code pattern. The set of the calculated distances is expressed as a three-dimensional measurement result image.

[0040] The three-dimensional measurement device 1 can be used for various applications. In this example, it is used for the application of measuring the workpiece WK conveyed on the conveyor C and its three-dimensional shape around it. Specifically, a projection pattern is projected from the projection unit 12 provided in the measurement head 10 toward the workpiece WK as the subject and its surroundings, and the workpiece WK onto which the projection pattern is projected and its surroundings are imaged by the imaging unit 13 provided in the measurement head 10.

[0041] <B. Schematic Configuration of Measurement Head> FIG. 2 is a schematic diagram showing the configuration of the functional blocks of the measurement head shown in FIG. 1. FIG. 3 is a schematic diagram showing the concept of the specific structure of the measurement head shown in FIG. 1. Next, with reference to FIGS. 2 and 3, the schematic configuration of the measurement head 10 will be described.

[0042] As shown in FIG. 2, the measurement head 10 includes a processing unit 11, the above-described projection unit 12 and imaging unit 13, a display unit 14, a storage unit 15, and a communication interface (I / F) unit 16. The projection unit 12 projects a projection pattern onto the subject as described above. The imaging unit 13 images the subject onto which the projection pattern is projected. In the present embodiment, the measurement head 10 includes one projection unit 12 and two imaging units 13.

[0043] The processing unit 11 is responsible for the overall processing in the measurement head 10. The processing unit 11 typically includes a processor, a storage for storing instruction codes executed by the processor, and a memory for expanding the instruction codes. In this case, the processor in the processing unit 11 expands the instruction codes in the memory and executes them to realize various processes. All or part of the processing unit 11 may be implemented using a dedicated hardware circuit (for example, an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array)).

[0044] The display unit 14 notifies various pieces of information acquired or calculated in the measurement head 10 to the outside.

[0045] The storage unit 15 stores images captured by the imaging unit 13, preset calibration parameters, and the like.

[0046] The communication interface unit 16 is responsible for exchanging data between the measuring head 10 and the image measuring device 1000 .

[0047] 3, the projection unit 12 has a light source 241 and a photomask 244 which are pattern illumination forming elements serving as optical devices, a lens assembly 226 (described later) which includes a projection lens 220 serving as an optical lens, a projection unit holder 210 (see FIG. 5, etc.), etc. The projection unit 12 is configured as an optical assembly configured by assembling together the light source 241, the photomask 244, the lens assembly 226, the projection unit holder 210, etc., and the detailed structure thereof will be described later.

[0048] The light source 241 irradiates light of a predetermined wavelength in the direction of the photomask 244. A predetermined pattern is formed on the photomask 244. The light that has passed through the photomask 244 is irradiated to the outside via the light projecting lens 220. As a result, the projection pattern is irradiated to the external space.

[0049] The imaging unit 13 includes an imaging device 341 as an optical device, a combined lens 326 described later that includes a light receiving lens 320 as an optical lens, and an imaging unit holder 310 (see FIG. 5 etc.). The imaging unit 13 is configured by an optical assembly in which these imaging device 341, combined lens 326, and imaging unit holder 310 etc. are assembled to each other, but the detailed structure thereof will be described later.

[0050]

[0051] <C. Overall Structure of the Measurement Head> FIG. 4 and FIG. 5 are schematic perspective views showing the external structure and internal structure of the measurement head shown in FIG. 1, respectively. FIG. 6 is a schematic plan view of the measurement head shown in FIG. 5. Next, with reference to FIGS. 4 to 6 and the aforementioned FIG. 3, the overall structure of the measurement head 10 according to the present embodiment will be described. Note that in FIGS. 5 and 6, illustration of some of the internal components is omitted.

[0052] As shown in FIG. 4, the measurement head 10 as an optical device has an outer shape of a substantially rectangular parallelepiped, and includes a housing 100, a projection unit 12 as an optical assembly, and a pair of imaging units 13 located on both sides adjacent thereto. The projection unit 12 and the pair of imaging units 13 are both housed inside the housing 100.

[0053] The housing 100 has a flat bottom plate portion 101 and a box-shaped lid portion 102 with an opening on the lower surface. The housing 100 has a substantially rectangular parallelepiped shape as a whole when the lower surface opening of the lid portion 102 is closed by the bottom plate portion 101. The bottom plate portion 101 and the lid portion 102 are fixed by screws not shown in the figure. Both the bottom plate portion 101 and the lid portion 102 are made of members of a metal with high thermal conductivity, and are preferably formed of an aluminum alloy or the like.

[0054] ​ A total of four windows are provided on the front surface of housing 100: illumination window 110, light projection window 120, and a pair of light receiving windows 130. Light-transmitting plates 111, 121, and 131 are fitted into illumination window 110, light projection window 120, and light receiving window 130, respectively.

[0055] An illumination light source 112, such as an LED (Light Emitting Diode), is disposed inside the housing 100 and at a position behind the illumination window 110. Light emitted from the illumination light source 112 passes through the above-mentioned light-transmitting plate 111 and is irradiated from the illumination window 110 toward the external space, thereby brightly illuminating the measurement area. The illumination light source 112 is provided in consideration of cases where there is no lighting equipment for illuminating the measurement area, and is used as illumination when the above-mentioned three-dimensional measurement is not being performed.

[0056] 5 and 6, the holder assembly 140 is housed inside the housing 100. The holder assembly 140 has a substantially rectangular parallelepiped shape and extends along the direction in which the projection unit 12 and the pair of imaging units 13 are aligned.

[0057] The holder assembly 140 has a projection unit holder 210 as a holder and a pair of image capture unit holders 310. The projection unit holder 210 is a cylindrical part that holds the lens pair 226 of the projection unit 12. The image capture unit holder 310 is a cylindrical part that holds the lens pair 326 of the image capture unit 13.

[0058] 3 to 6, the projection unit 12 is disposed inside the housing 100 and at a position behind the light-projection window 120. A lens assembly 226 is disposed at a position in front of the projection unit 12. The lens assembly 226 includes a light-projecting lens 220, a lens barrel 224 that holds the light-projecting lens 220 therein, and a sleeve 225 that holds the lens barrel 224 therein. The lens assembly 226 is disposed so that the light-projecting lens 220 faces the light-transmitting plate 121 that covers the light-projection window 120 described above.

[0059] Inside the projection unit 12, the light that passes through the photomask 244 and then exits the projection unit 12 through the projection lens 220 irradiates the external space from the light projection window portion 120 by passing through the above-described light-transmitting plate 121. Thereby, the projection pattern is irradiated toward the external space. As described above, three-dimensional measurement becomes possible when the projection pattern irradiated from the projection unit 12 is projected onto the workpiece WK and its surroundings.

[0060] Inside the housing 100 and at a position behind the light-receiving window portion 130, the imaging unit 13 is disposed. In front of the imaging unit 13, an objective lens assembly 326 is arranged. The objective lens assembly 326 includes a light-receiving lens 320, a lens barrel 324 that holds the light-receiving lens 320 inside, and a sleeve 325 that holds the lens barrel 324 inside. The objective lens assembly 326 is arranged such that the light-receiving lens 320 faces the light-transmitting plate 131 that covers the above-described light-receiving window portion 130.

[0061] The reflected light emitted from the workpiece WK onto which the projection pattern is projected and its surroundings enters the imaging unit 13 from the light-receiving window portion 130 by passing through the above-described light-transmitting plate 131, and is irradiated onto the image sensor 341 through the light-receiving lens 320. Thereby, as described above, three-dimensional measurement becomes possible when this light is received by the image sensor 341.

[0062] <D. Detailed Structure of the Measurement Unit> FIG. 7 is a schematic cross-sectional view of the projection part taken along line VII-VII shown in FIG. 6. FIG. 8 is a schematic cross-sectional view of the projection part taken along line VIII-VIII shown in FIG. 6. FIG. 9 is a schematic cross-sectional view of the projection part taken along line IX-IX shown in FIG. 6. FIG. 10 is a schematic cross-sectional view of the projection part taken along line XX shown in FIG. 6. FIG. 11(A) and FIG. 11(B) are enlarged perspective views of the main parts of the projection part holder and the imaging part holder shown in FIG. 5, respectively. FIG. 12 is an exploded perspective view showing the assembly structure of the measurement head shown in FIG. 5. FIG. 13 is a schematic cross-sectional view for explaining the stress applied to the sleeve, FIG. 13(A) is a schematic cross-sectional view when the distance between a pair of corners is smaller than half the outer diameter of the sleeve, and FIG. 13(B) is a schematic cross-sectional view when the distance between a pair of corners is equal to half the outer diameter of the sleeve. Next, a detailed structure of the measurement head 10 according to this embodiment will be described with reference to FIG. 7 to FIG. 13 and the above-mentioned FIG. 5 and FIG. 6.

[0063] 7 omits illustration of internal components of the projection unit 12 other than those related to the assembly of the lens combination 226 and the projection unit holder 210. Similarly, in Fig. 9 omits illustration of internal components of the imaging unit 13 other than those related to the assembly of the lens combination 326 and the imaging unit holder 310.

[0064] As shown in FIGS. 5 to 8 and 11 to 13, the lens assembly 226 of the projection unit 12 includes the light-projecting lens 220, the lens barrel 224, and the sleeve 225 as described above.

[0065] The projection lens 220 is configured as a compound lens in which a plurality of lenses 221-223 are combined. The plurality of lenses 221-223 are arranged inside the lens barrel 224 and aligned in the axial direction of the lens barrel 224 so that their optical axes overlap. Each of the plurality of lenses 221-223 has its periphery supported by the lens barrel 224. That is, the lens barrel 224 surrounds and supports the projection lens 220 in a direction perpendicular to the optical axis of the projection lens 220.

[0066] The sleeve 225 has a cylindrical shape. In this embodiment, a cylindrical sleeve is used as the sleeve 225. The sleeve 225 holds the projection lens 220 via the lens barrel 224 by being fixed in a state in which the lens barrel 224 is inserted therein. In this state, the axis of the sleeve 225 coincides with the axis of the lens barrel 224. That is, the multiple lenses 221 to 223 constituting the projection lens 220 are aligned along the axial direction of the sleeve 225 and are fixed to the sleeve 225 such that the optical axis of each lens overlaps with the axis of the sleeve 225.

[0067] The projection unit holder 210 is a cylindrical portion included in the above-mentioned holder connection body 140, and holds the lens assembly 226 of the projection unit 12. The projection unit holder 210 fixes the lens assembly 226 in a state where the sleeve 225 is inserted into the projection unit holder 210 so as to be arranged coaxially with the projection unit holder 210.

[0068] The projection unit holder 210 is made of a metal member having high thermal conductivity, such as an aluminum alloy, etc. This improves the workability of the projection unit holder 210, and makes it easy to provide the cutout portion 212a described below.

[0069] The projection unit holder 210 includes a substantially plate-shaped portion and a cylindrical portion standing forward from the substantially plate-shaped portion.

[0070] In this embodiment, the substantially flat plate-like portion and the cylindrical portion are provided with a through-hole 211 that penetrates them (see FIG. 11(A) in particular). Therefore, the projection unit holder 210 has a substantially cylindrical shape. The size of the through-hole 211 is configured to be the same as or slightly larger than the outer shape of the sleeve 225 of the lens assembly 226.

[0071] 11(A), a slit-shaped cutout portion 212a extending along the axial direction of the projection unit holder 210 is provided on the inner surface 212 of the projection unit holder 210. As a result, a pair of corners 214 positioned to sandwich the cutout portion 212a are provided on the inner surface 212 of the projection unit holder 210 so as to extend along the axial direction. This configuration makes it possible to achieve high-precision focus adjustment in the measurement head 10 as an optical device, the details of which will be described later.

[0072] It is preferable that the distance d between the pair of corners 214 is equal to or less than half the outer diameter R of the sleeve 225. This allows the lens assembly 226 including the sleeve 225 to slide stably along its axial direction within the projection unit holder 210, as will be described in detail later. Also, the lens assembly 226 can be firmly fixed to the projection unit holder 210.

[0073] The projection unit holder 210 is provided with a first through hole 215, a second through hole 216, and a third through hole 217 that penetrate the projection unit holder 210 so as to reach the inner surface 212 from the outer surface 213. The first through hole 215, the second through hole 216, and the third through hole 217 are arranged in this order along the front-to-rear direction of the projection unit holder 210. The first through hole 215, the second through hole 216, and the third through hole 217 are arranged at positions facing the cut-out portion 212a when viewed along the axial direction of the projection unit holder 210.

[0074] Spring plungers 401, 402 serving as elastic biasing members are inserted into the first through-hole 215 and the third through-hole 217, respectively. As a result, the spring plungers 401, 402 protruding toward the pair of corners 214 are provided on the inner surface 212 of the projection unit holder 210. The lens assembly 226 is elastically biased toward the pair of corners 214 by the spring plungers 401, 402. With this configuration, the lens assembly 226 can be temporarily fixed in the axial and radial directions of the projection unit holder 210 during the assembly process.

[0075] A fixing screw 403 serving as a fixing member is inserted into the second through hole 216. As a result, the fixing screw 403 protruding toward the pair of corners 214 is provided on the inner surface 212 of the projection unit holder 210. The fixing screw 403 abuts against the outer circumferential surface 225a of the sleeve 225 of the compound lens 226 to press the sleeve 225 toward the pair of corners 214.

[0076] Thereby, the compound lens 226 is fixed by being sandwiched between the fixing screw 403 and the pair of corners 214. As a result, the compound lens 226 is fixed in a state of contact with three points, the fixing screw 403 and the pair of corners 214. With this configuration, it becomes possible to firmly fix the compound lens 226 to the projection unit holder 210.

[0077] Furthermore, by using the fixing screw 403 as a fixing member, the lens assembly 226 can be fixed to the projection unit holder 210 with a simple configuration.

[0078] It is preferable that the tip of the fixing screw 403 has a substantially flat shape. This makes it possible to disperse the stress applied to the outer circumferential surface 225a of the sleeve 225 when the fixing screw 403 presses the sleeve 225, compared to when the tip of the fixing screw 403 has a pointed shape. As a result, the residual stress present in the outer circumferential surface 225a of the sleeve 225 after fixing is reduced, making it possible to suppress the occurrence of positional deviation of the lens assembly 226 over time.

[0079] Moreover, it is preferable that the outer circumferential surface 225a of the sleeve 225 has a substantially flat shape at the portion that contacts the fixing screw 403. This also makes it possible to disperse the stress applied to the outer circumferential surface 225a of the sleeve 225 when the fixing screw 403 presses the sleeve 225, thereby making it possible to suppress the occurrence of positional deviation of the lens assembly 226 over time.

[0080] Furthermore, as described above, by configuring the distance d between the pair of corners 214 to be equal to or less than half the outer diameter of the sleeve 225, the lens assembly 226 including the sleeve 225 can be stably slid along its axial direction within the projection unit holder 210. Also, the lens assembly 226 can be firmly fixed to the projection unit holder 210.

[0081] More specifically, as shown in Figures 13(A) and 13(B), when a vertical stress S1 is applied to the outer peripheral surface 225a of the sleeve 225 by the spring plungers 401, 402, a stress S2 is applied to the outer peripheral surface 225a of the sleeve 225 from one of the pair of corners 214, and a stress S3 is applied to the outer peripheral surface 225a of the sleeve 225 from the other of the pair of corners 214.

[0082] 13(A), when the distance d between the pair of corners 214 is smaller than half the outer diameter R of the sleeve 225, the vertical component SV2 of the stress S2 becomes larger than the horizontal component SH2 of the stress S2. Similarly, in this case, the vertical component SV3 of the stress S3 becomes larger than the horizontal component SH3 of the stress S3.

[0083] 13(B), when the distance d between the pair of corners 214 is equal to half the outer diameter R of the sleeve 225, the vertical component SV2 of the stress S2 is equal to the horizontal component SH2 of the stress S2. Similarly, in this case, the vertical component SV3 of the stress S3 is equal to the horizontal component SH3 of the stress S3.

[0084] With the above-mentioned configuration, a balance is achieved between the vertical stress S1 applied to the outer circumferential surface 225a of the sleeve 225 by the spring plungers 401, 402 and the vertical component SV2 of the above-mentioned stress S2 and the vertical component SV3 of the stress S3. As a result, it becomes possible to stably slide the compound lens 226 along its axial direction within the projection unit holder 210.

[0085] The above-mentioned stress relationship also holds true in the case where a vertical stress is applied to the outer circumferential surface 225a of the sleeve 225 by the fixing screw 403. Therefore, by configuring as described above, it becomes possible to firmly fix the lens assembly 226 to the projection unit holder 210.

[0086] As a result of the above, multiple lenses 221 to 223 serving as the projection lens 220 are arranged side by side on the optical axis of the projection lens 220 inside the projection unit 12, making it possible to project a projection pattern from the projection unit 12 towards the outside.

[0087] As shown in FIGS. 5, 6, 9 to 12, the lens assembly 326 of the imaging section 13 includes the light receiving lens 320, the lens barrel 324, and the sleeve 325, as described above.

[0088] Light receiving lens 320 is composed of a compound lens that combines multiple lenses 321-323. Multiple lenses 321-323 are arranged inside barrel 324 and aligned in the axial direction of barrel 324 so that their optical axes overlap. Each of multiple lenses 321-323 has its periphery supported by barrel 324. That is, barrel 324 surrounds and supports light receiving lens 320 in a direction perpendicular to the optical axis of light receiving lens 320.

[0089] Sleeve 325 has a tubular shape. In this embodiment, a cylindrical sleeve is used as sleeve 325. Sleeve 325 holds light receiving lens 320 via lens barrel 324 by being fixed with lens barrel 324 inserted therein. In this state, the axis of sleeve 325 coincides with the axis of lens barrel 324. That is, multiple lenses 321 to 323 constituting light receiving lens 320 are aligned along the axial direction of sleeve 325 and fixed to sleeve 325 such that the optical axis of each lens overlaps with the axis of sleeve 325.

[0090] The pair of imaging unit holders 310 are both cylindrical parts included in the above-mentioned holder connection body 140, and hold the lens assembly 326 of the imaging unit 13. The imaging unit holder 310 fixes the lens assembly 326 in a state where the sleeve 325 is inserted into the imaging unit holder 310 so as to be coaxial with the imaging unit holder 310.

[0091] The imaging unit holder 310 is made of a metal member having high thermal conductivity, such as an aluminum alloy, etc. This improves the workability of the imaging unit holder 310, and makes it easy to provide the cutout portion 312a described below.

[0092] The imaging unit holder 310 includes a substantially plate-shaped portion and a cylindrical portion standing forward from the substantially plate-shaped portion.

[0093] In this embodiment, the substantially flat plate-like portion and the cylindrical portion are provided with a through-hole 311 penetrating them (see FIG. 11(B) in particular). Therefore, the image pickup unit holder 310 has a substantially cylindrical shape. The size of the through-hole 311 is configured to be the same as or slightly larger than the outer shape of the sleeve 325 of the lens assembly 326.

[0094] 11(B), the inner surface 312 of the imaging unit holder 310 is provided with a slit-shaped cutout portion 312a extending along the axial direction of the imaging unit holder 310. As a result, the inner surface 312 of the imaging unit holder 310 is provided with a pair of corners 314 positioned to sandwich the cutout portion 312a and extending along the axial direction. With this configuration, it becomes possible to achieve high-precision focus adjustment in the measurement head 10 as an optical device, the details of which will be described later.

[0095] The distance between the pair of corners 314 is preferably equal to or less than half the outer diameter of the sleeve 325. This allows the lens assembly 326 including the sleeve 325 to slide stably along its axial direction within the image capture unit holder 310, similar to the relationship between the pair of corners 214 of the projection unit holder 210 described above and the sleeve 225. In addition, the lens assembly 326 can be firmly fixed to the image capture unit holder 310.

[0096] The imaging unit holder 310 is provided with a fourth through hole 315, a fifth through hole 316, and a sixth through hole 317 that penetrate the imaging unit holder 310 so as to reach the inner surface 312 from the outer surface 313. The fourth through hole 315, the fifth through hole 316, and the sixth through hole 317 are arranged in this order along the front-to-rear direction of the imaging unit holder 310. The fourth through hole 315, the fifth through hole 316, and the sixth through hole 317 are arranged at positions facing the cut-out portion 312a when viewed along the axial direction of the imaging unit holder 310.

[0097] Spring plungers 404, 405 as elastically biasing members are inserted into the fourth through hole 315 and the sixth through hole 317, respectively. As a result, the spring plungers 404, 405 protruding toward the pair of corners 314 are provided on the inner surface 312 of the imaging unit holder 310. The lens assembly 326 is elastically biased toward the pair of corners 314 by the spring plungers 404, 405. With this configuration, the lens assembly 326 can be temporarily fixed in the axial and radial directions of the imaging unit holder 310 during the assembly process.

[0098] A fixing screw 406 serving as a fixing member is inserted into the fifth through hole 316. As a result, the fixing screw 406 protruding toward the pair of corners 314 is provided on the inner surface 312 of the imaging unit holder 310. The fixing screw 406 abuts against the outer circumferential surface of the sleeve 325 of the compound lens 326 to press the sleeve 325 toward the pair of corners 314.

[0099] As a result, the lens assembly 326 is sandwiched and fixed by the fixing screw 406 and the pair of corner portions 314. Consequently, the lens assembly 326 is fixed in a state of being in contact with three points: the fixing screw 406 and the pair of corner portions 314. By configuring it in this way, it becomes possible to firmly fix the lens assembly 326 to the holder 310 for the imaging unit.

[0100] Moreover, by using the fixing screw 406 as the fixing member, the lens assembly 326 can be fixed to the holder 310 for the imaging unit with a simple configuration.

[0101] The tip of the fixing screw 406 preferably has a substantially planar shape, and the outer peripheral surface 325a of the sleeve 325 at the portion that contacts the fixing screw 406 preferably has a substantially planar shape. Thereby, similar to the case of explaining the outer peripheral surface 225a of the fixing screw 403 and the sleeve 225, it is possible to suppress the occurrence of displacement of the lens assembly 326 over time.

[0102] <E. Assembly Procedure of the Lens Assembly> FIGS. 14 to 16 are schematic cross-sectional views for explaining the assembly procedure of the internal structure of the measurement head shown in FIG. 5. Next, with reference to FIGS. 14 to 16, the assembly procedure of the lens assembly 326 that constitutes the imaging unit 13 of the measurement head 10 with respect to the holder 310 for the imaging unit will be described. Note that since the assembly procedure of the lens assembly 226 that constitutes the projection unit 12 to the holder 210 for the projection unit follows the assembly procedure of the lens assembly 326 to the holder 310 for the imaging unit, the description thereof will not be repeated.

[0103] When assembling the lens assembly 326 that constitutes the imaging unit 13 to the holder 310 for the imaging unit, first, as shown in FIG. 14, a lens assembly 326 in which the light receiving lens 320, the lens barrel 324, and the sleeve 325 are assembled to each other is prepared. At that time, as described above, the plurality of lenses 321 to 323 that constitute the light receiving lens 320 are arranged along the axial direction of the sleeve 325 and are fixed to the sleeve 325 so that the optical axis of each overlaps the axis of the sleeve 325.

[0104] Next, as shown in FIG. 14, an imaging unit holder 310 to which an imaging element 341 is attached is prepared.

[0105] 15, the lens assembly 326 is inserted into the through hole 311 of the image pickup unit holder 310. At this time, the lens assembly 326 is elastically biased toward the pair of corners 314 by the spring plungers 404, 405 as elastic biasing members inserted into the fourth through hole 315 and the sixth through hole 317 provided in the image pickup unit holder 310. This causes the outer circumferential surface 325a of the sleeve 325 to be in contact with the pair of corners 314. As a result, the lens assembly 326 is positioned relative to the image pickup unit holder 310 in the radial direction of the image pickup unit holder 310, and the lens assembly 326 is provisionally fixed in the axial and radial directions.

[0106] In addition, when inserting the lens group 326, the lens group 326 is positioned in the axial direction of the holder 310 for the imaging unit so that the positional relationship between the reference surface of the imaging element 341 pre-assembled in the holder 310 for the imaging unit and the reference surface of the lens group 326 is appropriate, thereby adjusting the focus.

[0107] Here, in the measurement head 10 of this embodiment, as described above, a cut-out portion 312a is provided on the inner surface 312 of the image capturing unit holder 310, so that a pair of corner portions 314 extending along the axial direction of the image capturing unit holder 310 are provided on the inner surface 312.

[0108] With this configuration, the lens assembly 326 slides in the imaging unit holder 310 along its axial direction with the outer circumferential surface 325 a of the sleeve 325 abutting against the pair of corners 314 .

[0109] In this way, the pair of corners 314 function as guides when positioning the lens assembly 326 relative to the imaging unit holder 310 in the axial direction, making it possible to adjust the focus of the imaging unit 13 with high precision.

[0110] In addition, the combined lens 326 in the state where focus adjustment has been performed by the above positioning is elastically biased by the spring plungers 404 and 405 as described above. As a result, the combined lens 326 is temporarily fixed in the axial direction and the radial direction.

[0111] Next, as shown in FIG. 16, the combined lens 326 in the temporarily fixed state as described above is fixed to the imaging unit holder 310.

[0112] More specifically, the combined lens 326 in the temporarily fixed state is pressed toward the pair of corner portions 314 by a fixing screw 406 as a fixing member inserted into a fifth through hole 316 provided in the imaging unit holder 310. As a result, the combined lens 326 is sandwiched and fixed by the fixing screw 406 and the pair of corner portions 314.

[0113] Through the above-described series of steps, the assembly of the combined lens 326 to the imaging unit holder 310 is completed. Further, by positioning the combined lens 326 with respect to the imaging unit holder 310 in this assembly, the focus adjustment of the imaging unit 13 is completed.

[0114] <F. Parentheses> By configuring as described above, in an optical device including a combined lens and a cylindrical holder that holds the combined lens, it is possible to improve the optical performance by realizing highly accurate focus adjustment.

[0115] That is, in the measurement head 10 according to the present embodiment, as described above, by providing the cutout portion 312a on the inner surface 312 of the imaging unit holder 310, a pair of corner portions 314 are formed on the inner surface 312.

[0116] In this configuration, when the lens assembly 326 is inserted into the image capturing unit holder 310, the lens assembly 326 slides along its axial direction inside the image capturing unit holder 310 with the outer peripheral surface 325a of the sleeve 325 abutting against the pair of corners 314. This allows the pair of corners 314 to function as guides when positioning the lens assembly 326 in the axial direction relative to the image capturing unit holder 310. As a result, it becomes possible to adjust the focus of the image capturing unit 13 with high precision. This effect is also achieved in the relationship between the lens assembly 226 and the projection unit holder 210.

[0117] Therefore, by using the measurement head 10 according to the present embodiment, it is possible to improve the optical performance by realizing highly accurate focus adjustment.

[0118] In the measurement head 10 according to this embodiment, the spring plungers 404, 405 serving as elastic biasing members are provided in the image capturing unit holder 310 as described above.

[0119] Thereby, the lens assembly 326 in a state where the focus has been adjusted by positioning is elastically biased toward the pair of corners 314, whereby the outer circumferential surface 325a of the sleeve 325 is brought into contact with the pair of corners 314. As a result, the lens assembly 326 is provisionally fixed in the axial and radial directions of the imaging unit holder 310.

[0120] In this configuration, it is possible to effectively prevent the precision of the focus adjustment from being reduced due to the lens assembly 326, which has been subjected to highly accurate focus adjustment, being displaced before being fixed to the imaging unit holder 310. This effect is also achieved in the relationship between the lens assembly 226 and the projection unit holder 210.

[0121] Furthermore, in the measurement head 10 according to this embodiment, as described above, the fixing screw 406 serving as a fixing member is provided in the imaging unit holder 310.

[0122] As a result, the assembled lens 326 in the temporarily fixed state as described above is pressed toward the pair of corner portions 314 by the fixing screw 406, and thereby the assembled lens 326 is sandwiched and fixed between the fixing screw 406 and the pair of corner portions 314.

[0123] When configured in this way, the assembled lens 326 that has been focused with high precision can be fixed to the imaging unit holder 310 so as to be immovable in both the axial direction and the radial direction of the imaging unit holder 310. Therefore, the measurement head 10 with high-precision focusing can be achieved. Note that this effect is similarly achieved in the relationship between the assembled lens 226 and the projection unit holder 210.

[0124] In the measurement head 10 according to the above-described embodiment, the removed portions 212a provided on the inner surface 212 of the projection unit holder 210 and the removed portions 312a provided on the inner surface 312 of the imaging unit holder 310 have both been exemplified and described as being slit-shaped. However, the removed portions 212a and 312a may be configured in a groove shape.

[0125] <G. Modified Example> FIG. 17 is a schematic perspective view showing the external structure of a measurement head according to a modified example. FIG. 18 is a schematic cross-sectional view of the projection unit shown in FIG. 17. Next, with reference to FIGS. 17 and 18, a three-dimensional measurement apparatus according to a modified example based on the above-described embodiment will be described. Note that in FIG. 18, a cross-section of the projection unit 12A corresponding to the portion in FIG. 8 is shown.

[0126] As shown in FIGS. 17 and 18, the measurement head 10A included in the three-dimensional measurement apparatus according to the modified example is different in that the number of imaging units 13A is one when compared with the measurement head 10 included in the three-dimensional measurement apparatus 1 according to the above-described embodiment.

[0127] In addition, when the measurement head 10A is compared with the measurement head 10, the configuration of the combined lens 226 of the projection unit 12A is different. More specifically, in the measurement head 10A, two anti-rotation recesses 225b are provided on a part of the outer peripheral surface 225a of the sleeve 225A of the combined lens 226. The two anti-rotation recesses 225b are located on the outer peripheral surface 225a of the portion where the spring plungers 401 and 402 abut.

[0128] In the measurement head 10A configured as described above, when the combined lens 226 is inserted into the projection unit holder 210, the spring plungers 401 and 402 come into contact with the anti-rotation recesses 225b. As a result, the rotation of the combined lens 226 with respect to the projection unit holder 210 is prevented.

[0129] Even in the case configured as described above, the same effects as those described in the above-described embodiment can be obtained, and in an optical device including a combined lens and a cylindrical holder that holds the combined lens, it is possible to improve the optical performance by realizing highly accurate focusing adjustment.

[0130] Also, when configured as described above, the rotation of the combined lens 226 with respect to the projection unit holder 210 is prevented as described above. Therefore, the combined lens 226 can be accurately positioned with respect to the projection unit holder 210 in its rotational direction.

[0131] In the above, the configuration of the sleeve 225A of the projection unit 12A has been described, but this configuration is similarly applicable to the combined lens 326 of the imaging unit 13A. That is, in this modification, two anti-rotation recesses are also provided on a part of the outer peripheral surface 325a of the sleeve 325 of the combined lens 326.

[0132] <H. Other Forms, etc.> In the above-mentioned embodiment, the present invention is applied to a measurement head of a three-dimensional measuring device having a single projection unit and two imaging units, and in the modified example based on the above-mentioned embodiment, the present invention is applied to a measurement head of a three-dimensional measuring device having a single projection unit and a single imaging unit, but the scope of application of the present invention is not limited to this type of application. In other words, the present invention can be applied to both a measurement head of a three-dimensional measuring device having multiple projection units and a single imaging unit, and a measurement head of a three-dimensional measuring device having multiple projection units and multiple imaging units.

[0133] In the above-described embodiment and its modified example, the use of the three-dimensional measuring device is exemplified as an use for measuring the three-dimensional shape of a workpiece transported on a conveyor, but the present invention can be applied to a measurement head of a three-dimensional measuring device used for various other uses. Here, examples of other uses include, for example, measuring the three-dimensional shape of a bulk pile of workpieces to individually recognize the three-dimensional position, orientation, etc. of each of the workpieces when the bulk pile of workpieces is individually picked up by a robot hand.

[0134] Furthermore, in the above-mentioned embodiment and its modified examples, a three-dimensional measurement device configured to project a projection pattern onto a subject using light of a predetermined wavelength has been described as an example, but the present invention can naturally be applied to the measurement head of a three-dimensional measurement device configured to project a projection pattern onto a subject by using light of multiple wavelengths or by using white light.

[0135] In the above-described embodiments and their modifications, the case where an LED is used as the light source of the pattern illumination forming element provided in the projection unit has been exemplified and described. However, as the light source, for example, an LD (Laser diode), a mercury lamp, or the like can also be used. As the pattern illumination forming element, for example, a combination of the above-described light source and a liquid crystal device, a combination of the above-described light source and a micromirror array (for example, a DMD (Digital Mirror Device) including a plurality of micromirrors that reflect light from the light source), organic EL (electro-luminescence), a micro LED arranged in an array, or the like can also be used.

[0136] Furthermore, in the above-described embodiments and their modifications, the case where the unique code method is applied to the three-dimensional measurement device has been exemplified and described. However, in addition to this, as the three-dimensional measurement device, there are those to which the random dot method, the phase shift method, the spatial code method, or the like is applied. The present invention can be applied to the measurement heads of any of these three-dimensional measurement devices, and its application is not limited to the measurement head of the three-dimensional measurement device to which the unique code method is applied.

[0137] Note that the application target of the present invention is not limited to the measurement head of the three-dimensional measurement device, and it can be applied to various other types of optical devices. However, even in that case, it goes without saying that it is limited to an optical device in which an optical assembly including a lens barrel that holds an optical lens and a mount member that supports the lens barrel is housed inside a housing.

[0138] <I. Supplementary Note> Summarizing the characteristic configuration of the three-dimensional measurement device according to the above-described embodiment, it is as follows. [Configuration 1] A combined lens (226, 326) including a plurality of lenses (221 to 223, 321 to 323) and sleeves (225, 225A, 325) that hold the plurality of lenses (221 to 223, 321 to 323), and a cylindrical holder (210, 310) for holding the lens pair (226, 326), the plurality of lenses (221-223, 321-323) are aligned along the axial direction of the sleeve (225, 225A, 325) and are fixed in a state of being inserted into the sleeve (225, 225A, 325) such that their optical axes overlap with the axis of the sleeve (225, 225A, 325); the lens assembly (226, 326) is fixed in a state where it is inserted into the holder (210, 310) so that the sleeve (225, 225A, 325) is arranged coaxially with the holder (210, 310); a groove- or slit-shaped cut-out portion (212a, 312a) extending along the axial direction of the holder (210, 310) is provided on the inner surface (212, 312) of the holder (210, 310), whereby a pair of corners (214, 314) positioned to sandwich the cut-out portion (212a, 312a) are provided on the inner surface (212, 312) of the holder (210, 310) and extend along the axial direction of the holder (210, 310); an optical device in which, when the lens group (226, 326) is inserted into the holder (210, 310), the lens group (226, 326) slides within the holder (210, 310) along the axial direction of the holder (210, 310) with the outer peripheral surface (225a, 325a) of the sleeve (225, 225A, 325) abutting against the pair of corners (214, 314), so that the pair of corners (214, 314) function as guides for positioning the lens group (226, 326) relative to the holder (210, 310) in the axial direction of the holder (210, 310). [Configuration 2] The inner surface (212, 312) of the holder (210, 310) is provided with elastic biasing members (401, 402, 404, 405) protruding toward the pair of corners (214, 314), the optical device according to configuration 1, wherein, when the lens group (226, 326) is inserted into the holder (210, 310), the elastic biasing member (401, 402, 404, 405) elastically biases the lens group (226, 326) toward the pair of corner portions (214, 314), thereby bringing the outer circumferential surface (225a, 325a) of the sleeve (225, 225A, 325) into contact with the pair of corner portions (214, 314). [Configuration 3] The outer circumferential surface (225a, 325a) of the sleeve (225, 225A, 325) is provided with a rotation prevention recess (225b), The optical device according to configuration 2, wherein when the lens group (226, 326) is inserted into the holder (210, 310), the elastic biasing member (401, 402, 404, 405) abuts against the anti-rotation recess (225b), thereby preventing rotation of the lens group (226, 326) relative to the holder (210, 310). [Configuration 4] The inner surface (212, 312) of the holder (210, 310) is provided with fixing members (403, 406) protruding toward the pair of corners (214, 314), The optical device according to any one of configurations 1 to 3, wherein the lens pair (226, 326) is pressed toward the pair of corner portions (214, 314) by the fixing member (403, 406), thereby sandwiching and fixing the lens pair (226, 326) between the fixing member (403, 406) and the pair of corner portions (214, 314). [Configuration 5] 5. The optical device according to claim 4, wherein the fixing members (403, 406) are fixing screws. [Configuration 6] 6. The optical device according to claim 5, wherein the tip of the fixing screw has a substantially flat shape. [Configuration 7] 7. The optical device according to configuration 5 or 6, wherein the outer circumferential surface (225a, 325a) of the sleeve (225, 225A, 325) that abuts against the fixing screw has a substantially flat shape. [Configuration 8] The sleeve (225, 225A, 325) is cylindrical, The optical device according to any one of configurations 1 to 7, wherein the distance between the pair of corner portions (214, 314) is equal to or less than half the outer diameter of the sleeve (225, 225A, 325). [Configuration 9] The optical device according to any one of configurations 1 to 8, wherein the holder (210, 310) is made of metal. [Configuration 10] a step of preparing a lens assembly (226, 326) including a plurality of lenses (221-223, 321-323) and a sleeve (225, 225A, 325) for holding the plurality of lenses (221-223, 321-323); A step of preparing a cylindrical holder (210, 310); and inserting the combined lens (226, 326) into the holder (210, 310), in a step of preparing the lens assembly (226, 326), the lenses (221-223, 321-323) are aligned along the axial direction of the sleeve (225, 225A, 325) and are fixed in a state in which the lenses are inserted into the sleeve (225, 225A, 325) such that their optical axes overlap with an axis of the sleeve (225, 225A, 325); in a step of preparing the holder (210, 310), a groove- or slit-shaped cutout portion (212a, 312a) extending along the axial direction of the holder (210, 310) is provided on an inner surface (212, 312) of the holder (210, 310), so that a pair of corner portions (214, 314) positioned to sandwich the cutout portion (212a, 312a) are provided on the inner surface (212, 312) of the holder (210, 310) and extend along the axial direction of the holder (210, 310); a manufacturing method for an optical device, in a step of inserting the lens group (226, 326) into the holder (210, 310), the lens group (226, 326) slides within the holder (210, 310) along the axial direction of the holder (210, 310) with the outer peripheral surface (225a, 325a) of the sleeve (225, 225A, 325) abutting the pair of corners (214, 314), thereby positioning the lens group (226, 326) relative to the holder (210, 310) in the axial direction of the holder (210, 310). [Configuration 11] In a step of preparing the holder (210, 310), elastic biasing members (401, 402, 404, 405) are provided on the inner surface (212, 312) of the holder (210, 310) so as to protrude toward the pair of corner portions (214, 314), 11. The method for manufacturing an optical device according to claim 10, wherein, in a step of inserting the pair of lenses (226, 326) into the holder (210, 310), the pair of lenses is elastically biased toward the pair of corner portions (214, 314) by the elastic biasing members (401, 402, 404, 405), thereby bringing the outer circumferential surface (225a, 325a) of the sleeve (225, 225A, 325) into contact with the pair of corner portions (214, 314). [Configuration 12] The method further includes a step of fixing the lens assembly (226, 326) to the holder (210, 310), in a step of preparing the holder (210, 310), fixing members (403, 406) protruding toward the pair of corner portions (214, 314) are provided on the inner surface (212, 312) of the holder (210, 310); A manufacturing method for an optical device according to configuration 10 or 11, wherein in a step of fixing the pair of lenses (226, 326) to the holder (210, 310), the pair of lenses (226, 326) in a state where they have been positioned relative to the holder (210, 310) is pressed toward the pair of corners (214, 314) by the fixing member (403, 406), thereby sandwiching and fixing the pair of lenses (226, 326) between the fixing member (403, 406) and the pair of corners (214, 314).

[0139] The above-mentioned embodiments disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0140] 1 Three-dimensional measuring device, 10, 10A Measuring head, 11 Processing unit, 12, 12A Projection unit, 13, 13A Imaging unit, 14 Display unit, 15 Memory unit, 16 Communication interface unit, 100 Housing, 101 Bottom plate unit, 102 Lid unit, 110 Illumination window unit, 111 Light-transmitting plate, 112 Illumination light source, 120 Light-projecting window unit, 121 Light-transmitting plate, 130 Light-receiving window unit, 131 Light-transmitting plate, 140 Holder connecting body, 210 Projection unit holder, 211 Through portion, 212 Inner surface, 212a Notch portion, 213 Outer surface, 214 Corner portion, 215 First through hole, 216 Second through hole, 217 Third through hole, 220 Light-projecting lens, 221 to 223 Lens, 224 Lens barrel, 225, 225A sleeve, 225a outer peripheral surface, 225b concave portion for preventing rotation, 226 lens group, 241 light source, 244 photomask, 310 holder for imaging unit, 311 through portion, 312 inner surface, 312a missing portion, 313 outer surface, 314 corner portion, 315 fourth through hole, 316 fifth through hole, 317 sixth through hole, 320 light receiving lens, 321 to 323 lens, 324 lens barrel, 325 sleeve, 325a outer peripheral surface, 326 lens group, 341 imaging element, 401, 402, 404, 405 spring plunger, 403, 406 fixing screw, 1000 image measuring device, C conveyor, WK work.

Claims

1. a lens assembly including a plurality of lenses and a sleeve for holding the plurality of lenses; and a cylindrical holder for holding the lens assembly, the plurality of lenses are aligned along the axial direction of the sleeve and are fixed in a state where they are inserted into the sleeve such that the optical axes of the lenses overlap with the axis of the sleeve; the lens assembly is fixed in a state where the sleeve is inserted into the holder so as to be coaxial with the holder; A groove-shaped or slit-shaped cutout portion extending along the axial direction of the holder is provided on the inner surface of the holder, so that a pair of corner portions positioned to sandwich the cutout portion are provided on the inner surface of the holder so as to extend along the axial direction of the holder, When the lens assembly is inserted into the holder, the outer peripheral surface of the sleeve abuts against the pair of corner portions and the lens assembly slides within the holder along the axial direction of the holder, thereby causing the pair of corner portions to function as guides for positioning the lens assembly relative to the holder in the axial direction of the holder.

2. The holder has an inner surface provided with an elastic biasing member protruding toward the pair of corner portions, 2. The optical device according to claim 1, wherein when the lens assembly is inserted into the holder, the lens assembly is elastically biased toward the pair of corner portions by the elastic biasing member, so that the outer peripheral surface of the sleeve abuts against the pair of corner portions.

3. The outer circumferential surface of the sleeve is provided with a rotation preventing recess, 3. The optical device according to claim 2, wherein when the compound lens is inserted into the holder, the elastic biasing member abuts against the anti-rotation recess, thereby preventing the compound lens from rotating relative to the holder.

4. A fixing member protruding toward the pair of corner portions is provided on the inner surface of the holder, 4. The optical device according to claim 1, wherein the lens assembly is pressed toward the pair of corner portions by the fixing member, so that the lens assembly is sandwiched and fixed between the fixing member and the pair of corner portions.

5. The optical device according to claim 4 , wherein the fixing member is a fixing screw.

6. The optical device according to claim 5 , wherein a tip of the fixing screw has a substantially flat shape.

7. The optical device according to claim 5 , wherein the outer circumferential surface of the sleeve in a portion that abuts against the fixing screw has a substantially flat shape.

8. the sleeve is cylindrical; The optical device according to claim 1 , wherein the distance between the pair of corners is equal to or less than half the outer diameter of the sleeve.

9. The optical instrument of claim 1 , wherein the holder is made of metal.

10. providing a lens assembly including a plurality of lenses and a sleeve for holding the plurality of lenses; A step of preparing a cylindrical holder; and inserting the lens assembly into the holder, In the step of preparing the lens assembly, the plurality of lenses are aligned along the axial direction of the sleeve and are fixed in a state in which the lenses are inserted into the sleeve such that the optical axes of the lenses overlap with an axis of the sleeve; In the step of preparing the holder, a groove-shaped or slit-shaped cutout portion extending along the axial direction of the holder is provided on the inner surface of the holder, so that a pair of corners positioned to sandwich the cutout portion are provided on the inner surface of the holder so as to extend along the axial direction of the holder, a lens assembly that is inserted into the holder and that slides within the holder along the axial direction of the holder with the outer peripheral surface of the sleeve abutting the pair of corner portions, thereby positioning the lens assembly relative to the holder in the axial direction of the holder.

11. In the step of preparing the holder, an elastic biasing member protruding toward the pair of corner portions is provided on the inner surface of the holder, 11. The method for manufacturing an optical device according to claim 10, wherein, in the process of inserting the lens assembly into the holder, the lens assembly is elastically biased by the elastic biasing member toward the pair of corner portions, so that the outer peripheral surface of the sleeve is in contact with the pair of corner portions.

12. The lens assembly may further include a step of fixing the lens assembly to the holder. In the step of preparing the holder, a fixing member protruding toward the pair of corner portions is provided on the inner surface of the holder, 11. The method for manufacturing an optical device according to claim 10, wherein in a step of fixing the compound lens to the holder, the compound lens, which has been positioned relative to the holder, is pressed toward the pair of corner portions by the fixing member, so that the compound lens is sandwiched and fixed between the fixing member and the pair of corner portions.

Images