Measuring device

Abstract

Provided is a measurement device provided with a small and lightweight movable body. A measurement device (1) is provided with: a movable unit (11) having a mirror (113); a movable unit (12) having a light emission point (121), a light incidence point (122) and an optical system; a drive mechanism (13); and a control unit (14). First light and second light emitted from a light emission point (121) are irradiated to a mirror (113) via an optical system, and first reflected light, which is reflected light of the first light from the mirror (113), and second reflected light, which is reflected light of the second light from the mirror (113), are incident to a light incidence point (122) via the optical system. The control unit (14) adjusts the position of the movable unit (12) by controlling the drive mechanism (13) on the basis of the respective intensities of the first reflected light and the second reflected light incident on the light incident point (122). A first wavelength, which is a peak wavelength of the first light, is different from a second wavelength, which is a peak wavelength of the second light, and the optical power at the first wavelength of the optical system is different from the optical power at the second wavelength of the optical system.

Description

Technical Field

[0001] The present disclosure relates to a measuring device. Background Art

[0002] A contact three-dimensional shape measuring instrument is used for highly precisely measuring shapes such as lenses. The configuration of an optical probe for a contact three-dimensional shape measuring instrument is disclosed in Patent Document 1.

[0003] (Prior Art Documents)

[0004] (Patent Documents)

[0005] Patent Document 1 Japanese Patent No. 3000819 Gazette Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] An object of the present disclosure is to provide a measuring device including a small and lightweight movable body.

[0008] Means for Solving the Problems

[0009] The measuring device according to one aspect of the present disclosure includes: a first movable body having a reflector; a second movable body having a light emission point, a light incident point, and an optical system; a drive mechanism that adjusts the position of the second movable body; and a control unit that controls the drive mechanism. First light and second light emitted from the light emission point are irradiated onto the reflector via the optical system, and first reflected light and second reflected light are each incident on the light incident point via the optical system. The first reflected light is the reflected light of the first light from the reflector, and the second reflected light is the reflected light of the second light from the reflector. The control unit controls the drive mechanism based on the intensities of the first reflected light and the second reflected light incident on the light incident point, and thereby adjusts the position of the second movable body. A first wavelength is different from a second wavelength. The first wavelength is the peak wavelength of the first light, and the second wavelength is the peak wavelength of the second light. The optical power of the optical system at the first wavelength is different from the optical power of the optical system at the second wavelength.

[0010] Advantages of the Invention

[0011] According to the present disclosure, it is possible to provide a measuring device including a small and lightweight movable body. Brief Description of the Drawings

[0012] Figure 1 It is a diagram showing a schematic configuration of the measuring device according to Embodiment 1.

[0013] Figure 2It is a diagram showing a schematic configuration of a measuring device according to a modification of Embodiment 1.

[0014] Figure 3 It is a diagram showing the relationship between the relative positions of two movable parts and the intensity of light.

[0015] Figure 4 It is a diagram showing the relationship between the wavelength of incident light and the focal length of an achromatic lens.

[0016] Figure 5 It is a diagram showing a schematic configuration of a measuring device according to Embodiment 2.

[0017] Figure 6 It is a diagram showing a schematic configuration of a conventional three-dimensional shape measuring instrument.

[0018] Description of Reference Numerals

[0019] 1, 1A, 2 Measuring devices

[0020] 10 Probe

[0021] 11, 12 Movable parts

[0022] 13 Driving mechanism

[0023] 14 Control unit

[0024] 15 Spring

[0025] 16, 17, 18 Optical fibers

[0026] 19 Optical circulator

[0027] 20, 20A Light source units

[0028] 21, 21a, 21b Laser elements

[0029] 22, 22a, 22b Optical systems

[0030] 23 Light combining element

[0031] 30, 30A Light intensity measurement units

[0032] 31a, 31b Photodetectors

[0033] 32 Light separation element

[0034] 33a, 33b AD conversion circuits

[0035] 34 Differential operation circuit

[0036] 40 Interferometer

[0037] 50 Air supply unit

[0038] 111 Probe

[0039] 112 Sliding part

[0040] 113 Mirror

[0041] 120a Guide mechanism

[0042] 120b Probe housing

[0043] 121 Light emission point

[0044] 122 Light incident point

[0045] 123 Collimating lens

[0046] 125 Condensing lens

[0047] 129 Optical element

[0048] 161, 162 Ends. Detailed implementation mode

[0049] (Summary of the present disclosure)

[0050] The inventors of the present invention have found the following problems with the optical probe used in the three-dimensional shape measuring instrument disclosed in Patent Document 1. Hereinafter, with reference to the configuration of the optical probe disclosed in Patent Document 1, the problems of the conventional optical probe will be described.

[0051] Figure 6 It is a schematic configuration diagram showing a conventional three-dimensional shape measuring instrument. As Figure 6 shown, the three-dimensional shape measuring instrument 1x includes an optical probe 10x. The optical probe 10x is composed of two elements, a movable part 11x and a movable part 12x.

[0052] The movable part 11x moves up and down along the shape of the measurement object (not shown). The three-dimensional shape measuring instrument 1x irradiates the movable part 11x with light Lx (shown by a dotted line in Figure 6 ) from the outside of the optical probe 10x, and determines the position of the movable part 11x based on the reflected light thereof. Accordingly, the three-dimensional shape measuring instrument 1x obtains the shape information of the measurement object.

[0053] The movable part 12x has a function of restricting the movement of the movable part 11x in the vertical direction. Further, the movable part 11x and the movable part 12x are connected by a spring 15x. In order to keep the contact strength between the movable part 12x and the measurement object within a certain range, it is necessary to keep the relative position between the movable part 11x and the movable part 12x within a certain range.

[0054] In the configuration of Patent Document 1, the objective lens 125x is placed in the movable part 12x. The objective lens 125x condenses the light incident from the outside of the optical probe 10x onto the mirror 113x on the movable part 11x. The objective lens 125x emits the reflected light reflected by the mirror 113x to a laser length gauge (not shown) outside the optical probe 10x. In order for the reflected light to return to the laser length gauge, it is necessary to position the mirror 113x of the movable part 11x near the focal position of the objective lens 125x of the movable part 12x. From this perspective, in the optical probe 10x, it is necessary to keep the relative position between the movable part 11x and the movable part 12x within a certain range.

[0055] The movable part 12x includes a semiconductor laser 21x, photo detectors 31ax and 31bx, and is used as a unit for measuring the relative position between the movable part 11x and the movable part 12x. The reason why the movable part 12x includes two photo detectors 31ax and 31bx is that the signal intensities of the detected signals have different dependencies on the relative position between the movable part 11x and the movable part 12x. With this configuration, when deviating from the desired relative position, in order to reach the desired relative position, it is possible to calculate in which direction and by how much the movable part 12x needs to be moved.

[0056] As Figure 6 shown, the contact three-dimensional shape measuring instrument 1x includes a drive unit 13x and a relative position measuring unit 14x.

[0057] The relative position measuring unit 14x calculates the relative position between the movable part 11x and the movable part 12x based on the outputs of the photo detectors 31ax and 31bx respectively. The drive unit 13x adjusts the relative position between the movable part 11x and the movable part 12x by changing the position of the movable part 12x while keeping the relative position unchanged.

[0058] In order to measure the three-dimensional shape of the measurement object, the three-dimensional shape measuring instrument 1x changes the relative position in the horizontal direction between the optical probe 10x and the measurement object. In this case, the movable part 11x changes its position in the vertical direction according to the shape of the measurement object. Whenever the relative position in the horizontal direction is changed, in order to keep the relative position between the movable part 11x and the movable part 12x unchanged, it is necessary to measure the relative position and change the position of the movable part 12x.

[0059] However, if the position change speed of the movable part 12x is slow, it will restrict the shape measurement. And when the position change cannot be carried out immediately, the relative position between the movable part 11x and the movable part 12x will exceed the appropriate range. In this case, there will be problems such as the movable part 11x pressing the measurement object excessively, or the movable part 11x leaving the measurement object and unable to perform normal measurement.

[0060] The weight of the movable part 12x affects the position change speed of the movable part 12x. In order to increase the position change speed, it is necessary to make the movable part 12x as light as possible. Further, in order to suppress the physical interference between the measurement object and the movable part 12x, it is necessary to make the movable part 12x as small as possible.

[0061] Accordingly, an object of the present disclosure is to provide a measuring device including a small and lightweight movable body.

[0062] The measuring device according to the first aspect of the present disclosure includes: a first movable body having a reflector; a second movable body having a light emission point, a light incident point, and an optical system; a drive mechanism that adjusts the position of the second movable body; and a control unit that controls the drive mechanism, and first light and second light emitted from the light emission point are irradiated onto the reflector via the optical system, and first reflected light and second reflected light are each incident on the light incident point via the optical system, the first reflected light being the reflected light of the first light from the reflector, the second reflected light being the reflected light of the second light from the reflector, and the control unit controls the drive mechanism based on the intensities of the first reflected light and the second reflected light incident on the light incident point, thereby adjusting the position of the second movable body, a first wavelength being different from a second wavelength, the first wavelength being the peak wavelength of the first light, the second wavelength being the peak wavelength of the second light, and the optical power of the optical system at the first wavelength being different from the optical power of the optical system at the second wavelength.

[0063] Accordingly, by using an optical system having different optical powers at the first wavelength and the second wavelength, it is possible to make the intensities of the first reflected light and the second reflected light incident on the light incident point different. Based on this intensity difference, the relative positions of the first movable body and the second movable body can be calculated and adjusted. Since there is no need to provide light incident points for each wavelength, the number of components arranged on the second movable body can be reduced. Therefore, miniaturization and lightening of the second movable body can be achieved.

[0064] The measuring device according to the second aspect of the present disclosure is the measuring device according to the first aspect, and includes an optical fiber, and both the light emission point and the light incident point are the first end portion of the optical fiber.

[0065] Accordingly, since the light emission point and the light incident point are the ends of the optical fiber, it is possible to miniaturize and lighten the second movable body. This is because the size of the end of the optical fiber is generally smaller than that of the semiconductor laser and the optical detector, so it can contribute to the miniaturization and lightening of the second movable body. Also, when components such as a semiconductor laser and an optical detector are provided, power supply power lines for operating the components and signal lines for extracting signals output from the components are required. In this regard, by using an optical fiber, there is no need to provide power lines and signal lines, thus reducing the number of cables connected to the second movable body. In this respect, the miniaturization and lightening of the second movable body can also be achieved.

[0066] The measuring device according to the third aspect of the present disclosure is the measuring device according to the first aspect or the second aspect, and the wavelength components of the first light and the second light having intensities equal to or higher than a specified value do not overlap with each other.

[0067] Accordingly, it is only necessary to detect the light intensities of the two wavelengths of the first wavelength and the second wavelength. Compared with the case of performing spectroscopy and spectral measurement, the amount of calculation and the calculation time can be reduced, so the relative position between the first movable body and the second movable body can be calculated and adjusted in a short period. Therefore, it can contribute to the high-speed measurement of the measurement object.

[0068] The measuring device according to the fourth aspect of the present disclosure is the measuring device according to any one of the first aspect to the third aspect. In the measurement of the object, the light used is incident on the optical system. The third wavelength is different from both the first wavelength and the second wavelength, and the third wavelength is the peak wavelength of the light used in the measurement of the object. The optical power of the optical system at the third wavelength is approximately equal to one of the optical power of the optical system at the first wavelength and the optical power of the optical system at the second wavelength and different from the other.

[0069] Accordingly, it is possible to easily separate the light used in the measurement of the measurement object from the light used in the measurement of the relative position between the first movable body and the second movable body. In this way, the adverse effects caused by each other's light can be suppressed, and thus the measurement accuracy of each can be improved.

[0070] The measuring device according to the fifth aspect of the present disclosure is the measuring device according to the fourth aspect, and the measuring device includes an interferometer that causes the light used in the measurement of the object to interfere.

[0071] Accordingly, the surface shape of the measurement object can be measured based on the distance measurement using the interference of light.

[0072] The measuring device according to the sixth aspect of the present disclosure is the measuring device according to any one of the first to fifth aspects, and the measuring device includes a light intensity measuring unit that measures the intensity of each of the first reflected light and the second reflected light incident on the light incident point.

[0073] Accordingly, since the light intensity measuring unit can be separately provided from the second movable body, it is easy to replace when the light intensity measuring unit deteriorates.

[0074] The measuring device according to the seventh aspect of the present disclosure is the measuring device according to the sixth aspect, and the light intensity measuring unit includes: a first photodiode that performs photoelectric conversion on the first reflected light and outputs a first signal; a second photodiode that performs photoelectric conversion on the second reflected light and outputs a second signal; a first circuit that performs analog-to-digital conversion on the first signal; and a second circuit that is different from the first circuit and performs analog-to-digital conversion on the second signal.

[0075] Accordingly, it is only necessary to detect the light intensities of only two wavelengths, i.e., the first wavelength and the second wavelength. Compared with the case of performing spectroscopy and spectral measurement, since the amount of calculation and the calculation time can be reduced, the relative position between the first movable body and the second movable body can be calculated and adjusted in a short period. Therefore, it is possible to contribute to the high-speed measurement of the measurement object.

[0076] The measuring device according to the eighth aspect of the present disclosure is the measuring device according to the sixth aspect, and the light intensity measuring unit includes: a first photodiode that performs photoelectric conversion on the first reflected light and outputs a first signal; a second photodiode that performs photoelectric conversion on the second reflected light and outputs a second signal; and a differential operation circuit that receives inputs of the first signal and the second signal respectively.

[0077] Accordingly, it is only necessary to detect the light intensities of only two wavelengths, i.e., the first wavelength and the second wavelength. Compared with the case of performing spectroscopy and spectral measurement, since the amount of calculation and the calculation time can be reduced, the relative position between the first movable body and the second movable body can be calculated and adjusted in a short period. Therefore, it contributes to the high-speed measurement of the measurement object.

[0078] The measuring device according to the ninth aspect of the present disclosure is the measuring device according to the second aspect, and the measuring device includes a light source unit. The light emitted from the light source unit is incident from an end portion of the optical fiber opposite to the first end portion, and is transmitted in the optical fiber and emitted from the first end portion as the first light and the second light.

[0079] Accordingly, since the light source unit can be separately provided from the second movable body, replacement when the light source unit deteriorates becomes easy. Also, it is possible to suppress a decrease in the measurement accuracy of the measurement object due to the heat generated by the light source unit during light emission.

[0080] The measuring device according to the tenth aspect of the present disclosure is the measuring device according to the ninth aspect, and the light source unit includes a first laser light source that emits the first light and a second laser light source that is different from the first laser light source and emits the second light.

[0081] Accordingly, it is possible to independently use the laser light sources that emit light corresponding to the wavelengths.

[0082] The measuring device according to the eleventh aspect of the present disclosure is the measuring device according to the ninth aspect, and the light source unit includes a laser light source having a first active region that emits the first light and a second active region that emits the second light.

[0083] Accordingly, it is possible to make the laser light source one, and thus it is possible to simplify the configuration of the light source unit.

[0084] The measuring device according to the twelfth aspect of the present disclosure is the measuring device according to the ninth aspect, and the light source unit is a gas laser light source that emits the first light and the second light.

[0085] Accordingly, it is possible to make the laser light source one, and thus it is possible to simplify the configuration of the light source unit. Also, in the measuring device of the present disclosure, it is possible to use various light sources without relying on the principle of laser oscillation.

[0086] The measuring device according to the thirteenth aspect of the present disclosure is the measuring device according to any one of the first aspect to the twelfth aspect, and the optical system includes an achromatic lens.

[0087] Accordingly, by the achromatic lens, it is possible to make the third wavelength of the light used for measuring the measurement object almost equal to one of the first wavelength of the first light and the second wavelength of the second light used for measuring the relative position of the first movable body and the second movable body and different from the other. Therefore, it is possible to easily separate the light used for measuring the measurement object from the light used for measuring the relative position of the first movable body and the second movable body. In this way, it is possible to suppress the adverse effects caused by each other's light, and thus it is possible to improve each measurement accuracy.

[0088] Hereinafter, embodiments of the present disclosure will be specifically described with reference to the drawings.

[0089] In addition, the embodiments described below are all general or specific examples. The numerical values, shapes, materials, constituent elements, arrangement positions of the constituent elements, connection methods, steps, order of steps, etc. shown in the following embodiments are all examples, and their main purpose is not to limit the present disclosure. In addition, among the constituent elements of the following embodiments, the constituent elements not described in the independent claims will be described as optional constituent elements.

[0090] Moreover, each figure is only a schematic diagram for conceptual illustration, and is not the actual size, shape, etc. Therefore, for example, the scales in each figure do not have to be the same. In each figure, the same reference numerals are given to substantially the same constituent elements, and repeated descriptions are omitted or simplified.

[0091] In this specification, the light emission point is the part where light exits into the interior of the second movable body and is a part having a predetermined area. For example, the light emission point is the end of an optical fiber or the light emission surface of a light emitting element. The light incidence point is the part where the light propagating inside the second movable body enters the light detector and is a part having a predetermined area. For example, the light incidence point is the end of an optical fiber or a pinhole.

[0092] In this specification, the "vertical direction" refers to the direction in which the relative position of the first movable body and the second movable body can change. Specifically, the direction parallel to the axis of the probe of the first movable body is the vertical direction. Along the axis of the probe, the tip direction is the "downward direction", and the opposite direction is the "upward direction". The tip of the probe contacts the measurement object.

[0093] In this specification, ordinal numbers such as "first" and "second" do not mean the number or order of constituent elements, etc. without special limitations, but are used for the purpose of distinguishing to avoid confusion of the same kind of constituent elements.

[0094] (Embodiment 1)

[0095] First, the measuring device according to Embodiment 1 will be described. The measuring device according to this embodiment has a configuration in which, instead of providing a laser light source and a light detector in the movable part, the end of an optical fiber is connected to the movable part.

[0096] Hereinafter, Figure 1 the specific configuration of the measuring device according to this embodiment will be described. Figure 1 FIG. is a diagram showing a schematic configuration of the measuring device according to this embodiment.

[0097] The measuring device 1 according to this embodiment is a three-dimensional shape measuring instrument. Specifically, the measuring device 1 measures the surface shape of a measurement object (not shown). As Figure 1As shown, the measuring device 1 includes a probe 10, a drive mechanism 13, a control unit 14, a spring 15, optical fibers 16, 17, and 18, and an optical circulator 19. Further, the measuring device 1 includes a light source unit 20, a light intensity measurement unit 30, an interferometer 40, and an air supply unit 50.

[0098] [Probe]

[0099] The probe 10 includes a movable part 11 and a movable part 12. The movable part 11 is an example of a first movable body having a reflector. The movable part 12 is an example of a second movable body having a light emission point, a light incidence point, and an optical system.

[0100] The movable part 11 includes a probe tip 111, a sliding part 112, and a mirror 113. The probe tip 111 is fixed to the sliding part 112. When measuring a measurement object, the tip of the probe tip 111 contacts the measurement object. When the probe tip 111 contacts the measurement object, the movable part 11 changes its position in the vertical direction according to the shape of the measurement object. The sliding part 112 restricts the movement of the movable part 11 in the vertical direction. The mirror 113 is an example of the reflector included in the first movable body. The relative positional relationship among the probe tip 111, the sliding part 112, and the mirror 113 is fixed.

[0101] The movable part 12 includes a guide mechanism 120a and a probe housing 120b. The relative positional relationship between the guide mechanism 120a and the probe housing 120b is fixed. In the present embodiment, the movable part 12 has a light emission point 121 and a light incidence point 122. The light emission point 121 is the same as the light incidence point 122 and is the end 161 of the optical fiber 16. Further, the movable part 12 has an optical system fixed to the probe housing 120b.

[0102] The optical system includes a collimating lens 123, a focusing lens 125, and an optical element 129.

[0103] The collimating lens 123 converts the light emitted from the light emission point 121 into light that is close to parallel (hereinafter referred to as parallel light). Light that is close to parallel means that the light incident on the collimating lens 123, that is, in the present embodiment, light having a divergence angle smaller than the light emitted from the end 161 of the optical fiber 16. Further, the collimating lens 123 condenses the light that enters from the opposite direction, specifically, the reflected light reflected by the mirror 113, near the end 161 of the optical fiber 16 that serves as the light incidence point 122.

[0104] The condenser lens 125 condenses the incident light near the mirror 113. For example, the condenser lens 125 condenses the parallel light transformed by the collimator lens 123 and reflected by the optical element 129 near the mirror 113. Also, the condenser lens 125 transforms the reflected light reflected by the mirror 113 into parallel light and makes it incident on the collimator lens 123 via the optical element 129. And in the present embodiment, the condenser lens 125 condenses the light L for measuring the object to be measured near the mirror 113. Further, the condenser lens 125 transforms the reflected light of the light L that has passed through the mirror 113 into parallel light and makes it incident on the interferometer 40 via the optical element 129.

[0105] The optical element 129 is an optical element that superimposes the optical path of the measurement light L used by the interferometer 40 and the light for measuring the relative positions of the movable parts 11 and 12 and makes it incident on the mirror 113. And the optical element 129 separates the reflected light reflected from the mirror 113 and transmitted through the condenser lens 125 into the reflected light incident on the interferometer 40 and the reflected light for measuring the relative positions of the movable parts 11 and 12. The optical element 129 is, for example, a dichroic mirror, but may also be a semi-transmissive semi-reflective mirror, a beam splitter cube, a cube polarization beam splitter, etc.

[0106] For example, as long as the wavelength of the light L used by the interferometer 40 is different from the wavelength of the light for measuring the relative positions of the movable parts 11 and 12, the optical paths of the two lights can be made to coincide or almost completely separated by an optical element having wavelength dependence such as a dichroic mirror. In Figure 1 the configuration, a dichroic mirror that transmits the light L used by the interferometer 40 and reflects the light for measuring the relative positions of the movable parts 11 and 12 is adopted as the optical element 129.

[0107] Alternatively, as long as the polarization of the light L used by the interferometer 40 is different from the polarization of the light for measuring the relative positions of the movable parts 11 and 12, the optical paths of the two lights can be made to coincide or almost completely separated by an optical element having polarization dependence such as a cube polarization beam splitter. And it may also be that, in the case of adopting an unpolarized beam splitter and having a configuration in which the optical paths of the light used by the interferometer 40 and the light for measuring the relative positions of the movable parts 11 and 12 are superimposed, an optical element that transmits one light and blocks the other light can be arranged on the optical path where the two lights are to be separated. For example, a notch filter, a band-pass filter, a long-pass filter, or a short-pass filter, etc. can be arranged.

[0108] In the present embodiment, the optical system included in the movable part 12 may further include an optical element having optical power in addition to the collimator lens 123 and the condenser lens 125. Also in the present embodiment, an optical element for adjusting the optical path may be provided so that the light passing through the collimator lens 123 is incident on the condenser lens 125.

[0109] In the present embodiment, the light emitted from the light emission point 121 includes first light and second light. The first light and the second light are irradiated onto the mirror 113 via the optical system included in the movable part 12. Specifically, after the first light and the second light are converted into parallel light by the collimator lens 123, they are reflected by the optical element 129 and condensed by the condenser lens 125 near the mirror 113. The first wavelength λ 1 which is the peak wavelength of the first light 2 is different from the second wavelength λ

[0110] which is the peak wavelength of the second light. 1 The reflected light reflected from the mirror 113 includes first reflected light and second reflected light. The first reflected light is the reflected light of the first light from the mirror 113. The second reflected light is the reflected light of the second light from the mirror 113. In the present embodiment, the peak wavelength of the first reflected light is the same as the peak wavelength of the first light, which is the first wavelength λ 2 ; and the peak wavelength of the second reflected light is the same as the peak wavelength of the second light, which is the second wavelength λ

[0111] The optical power of the optical system included in the movable part 12 for the light of the first wavelength λ 1 is different from the optical power of the optical system for the light of the second wavelength λ 2 . Specifically, at least one of the optical elements located on the optical path through which the first light and the second light pass among the optical elements included in the optical system included in the movable part 12 has different optical powers for the light of the first wavelength λ 1 and for the light of the second wavelength λ 2 .

[0112] In addition, the optical power is proportional to the reciprocal of the focal length. In this specification, two optical powers being different means that the two optical powers are not in a state of being almost equal. Two optical powers being almost equal means that the ratio of the difference between the two optical powers is less than 10% with respect to the larger of the two optical powers. Therefore, two optical powers being different means that the ratio of the difference between the two optical powers is 10% or more with respect to the larger of the two optical powers.

[0113] The optical power for the first wavelength λ 1 is different from the optical power for the second wavelength λ 2Although the components with different optical powers are the collimating lens 123 or the condenser lens 125, they can also be optical components other than these lenses. For example, a component with a strong wavelength dependence of optical power such as a diffractive optical element can be arranged on the optical path through which both the first light and the second light pass.

[0114] Alternatively, it can also be configured such that the optical power of the collimating lens 123 is almost the same for the first light and the second light, while the difference in the optical powers of the first light and the second light is increased in other optical components. In the case of adopting this configuration, when the first light and the second light emitted from the end 161 of the optical fiber 16 enter the collimating lens 123, both of them will be transformed into parallel light (collimated light beam). The advantage in this case is that the calculation of the ratio of the first light and the second light returning to the end 161 of the optical fiber 16 due to the change in the relative positions of the movable part 11 and the movable part 12 becomes easy, so the design and adjustment of the device also become easy.

[0115] The relative position of the movable part 12 with respect to the movable part 11 is variable. The guide mechanism 120a of the movable part 12 restricts the movement of the movable part 11 in the vertical direction. An air supply part 50 is connected to the movable part 11. By the air supplied from the air supply part 50, the movement of the movable part 11 can be made smooth.

[0116] In the present embodiment, the movable part 11 and the movable part 12 are connected by a spring 15. The spring 15 is an example of the elastic body included in the measuring device 1. The spring 15 applies a force to the movable part 11 in the direction of pushing the movable part 11 against the measurement object (specifically, the downward direction). Thereby, the contact between the probe 111 and the measurement object can be easily ensured, and the reliability of the measurement can be improved.

[0117] The measuring device 1 may include rubber, which is another example of the elastic body, instead of the spring 15. And the measuring device 1 may not include an elastic body. For example, the movable part 11 and the movable part 12 can be connected by a mechanism using a magnet or the like.

[0118] [Drive mechanism]

[0119] The drive mechanism 13 adjusts the position of the movable part 12. Specifically, the drive mechanism 13 receives a control signal from the control part 14 and changes the position of the movable part 12. The drive mechanism 13 is, for example, a linear motor or the like, but there is no particular limitation as long as it can adjust the position of the movable part 12.

[0120] [Control part]

[0121] The control part 14 controls the drive mechanism 13. The control part 14 is a control signal generation part that generates a control signal output to the drive mechanism 13.

[0122] Specifically, the control unit 14 controls the drive mechanism 13 based on the intensities of the first reflected light and the second reflected light incident on the light incident point 122, and thereby adjusts the position of the movable unit 12. More specifically, the control unit 14 calculates the relative position between the movable unit 11 and the movable unit 12 based on the output signal from the light intensity measurement unit 30. In order to keep the calculated relative position within a specified range, the control unit 14 calculates the distance and direction by which the movable unit 12 should be moved. Then, the control unit 14 sends a control signal for moving the movable unit 12 by the calculated distance in the calculated direction to the drive mechanism 13. The method for calculating the relative position between the movable unit 11 and the movable unit 12 will be described later.

[0123] [Optical fiber]

[0124] The optical fiber 16 has an end portion 161 and an end portion 162.

[0125] The end portion 161 is an example of the first end portion and is the light emission point 121 of the movable unit 12. Also, the end portion 161 is the light incident point 122 of the movable unit 12. The end portion 161 is directly or via other components fixed to the probe housing 120b which is a component of the probe 10.

[0126] The end portion 162 is the end portion of the optical fiber 16 on the side opposite to the end portion 161. The end portion 162 is not fixed to the probe housing 120b. The end portion 162 is connected to the optical circulator 19. One end of the optical fiber 17 and one end of the optical fiber 18 are respectively connected to the optical circulator 19.

[0127] The optical circulator 19 is an example of a directional coupler, which makes the light emitted from the light source unit 20 and transmitted in the optical fiber 17 incident on the optical fiber 16 instead of the optical fiber 18. Also, the optical circulator 19 makes the reflected light incident on the optical fiber 16 from the light incident point 122 and transmitted in the optical fiber 16 incident on the optical fiber 18 instead of the optical fiber 17. In this way, the optical circulator 19 can separate the input / output paths of the light. By using the optical circulator 19, the utilization efficiency of the light emitted from the light source unit 20, the utilization efficiency of the reflected light to be measured, and the signal-to-noise ratio can be improved.

[0128] In addition, the optical circulator 19 is not necessarily used, and a configuration using a non-directional coupler such as a separator may also be adopted. Also, for example, instead of the optical fibers 16, 17, 18, and the optical circulator 19, a bifurcated optical fiber may be used, and one of the two end portions may be fixed to the probe housing 120b.

[0129] The other end of the optical fiber 17 is connected to the light source unit 20, and light from the light source unit 20 is incident thereon. The light emitted from the light source unit 20 propagates in the optical fiber 17, passes through the optical circulator 19, and is incident from the end 162 of the optical fiber 16. After propagating in the optical fiber 16, it is emitted from the end 161.

[0130] The other end of the optical fiber 18 is connected to the light intensity measurement unit 30, and the first reflected light and the second reflected light that propagate in the optical fiber 18 are emitted to the light intensity measurement unit 30.

[0131] In addition, the optical fiber 17 can be a fiber laser in which the optical fiber itself emits light. Alternatively, the optical fiber 17 can be a fluorescent optical fiber or a non-linear optical fiber having a wavelength conversion function. In this case, the optical fiber 17 can emit only the wavelength-converted light, or can emit both the light before wavelength conversion and the wavelength-converted light. In this way, the optical fiber 17 can be integrated with the light source unit 20.

[0132] The optical fibers 16, 17, and 18 can be single-mode optical fibers or multi-mode optical fibers. For example, when the optical fiber 16 is a single-mode optical fiber, the light emission point 121 and the light incident point 122 can be made smaller. By making the light emission point 121 and the light incident point 122 smaller, an optical path with a small divergence angle can be formed by the optical system of the movable part 12. Accordingly, it is easy to assemble a system in which the photodetectors 31a and 31b are sensitive to changes in the light quantity with respect to changes in the relative positions of the movable part 11 and the movable part 12. When the optical fiber 16 is a multi-mode optical fiber, there is an advantage that the light emitted from the light source unit 20 is easily incident on the end 162 of the optical fiber 16. Therefore, it is advantageous from the viewpoint of the signal-to-noise ratio.

[0133] Moreover, the optical fibers 16, 17, and 18 can also be polarization-maintaining optical fibers. By using polarization-maintaining optical fibers, it becomes easy to separate the light L used in the interferometer 40 and the light for measuring the relative positions of the movable part 11 and the movable part 12 by polarization optical elements.

[0134] [Light source unit]

[0135] The light source unit 20 emits light that can be detected by the light intensity measurement unit 30. There is no particular limitation on the wavelength of the light emitted from the light source unit 20. For example, as long as the wavelength is different from the wavelength of the light used in the interferometer 40, the separation of the two by an optical element 129 such as a dichroic mirror becomes easy.

[0136] In this embodiment, the light source unit 20 emits first light and second light. The spectra of the first light and the second light are both lights with a narrow distribution width. The distribution width can be represented by a spectral width having a prescribed intensity or more. For example, the half-width is an example of the distribution width. The narrower the distribution widths of the spectra of the first light and the second light are, the more sensitive the change in the amount of light incident on the optical fiber 16 due to the change in the relative positions of the movable part 11 and the movable part 12 can be made. For example, the half-width of the spectrum of the first light and the half-width of the spectrum of the second light are both 50 nm or less. Alternatively, the half-width of the spectrum of the first light and the half-width of the spectrum of the second light may both be 10 nm or less. For example, the wavelength components of the first light and the second light having a prescribed intensity or more do not overlap with each other. The prescribed intensity is, for example, half of the peak intensity of each light.

[0137] In this way, by making the spectra of the first light and the second light into different narrow distribution widths from each other, the separation between the first light and the second light becomes easy, and the curve indicated by the intensity of the first light and the curve indicated by the intensity of the second light can be made sufficiently different with respect to the relative positions of the movable part 11 and the movable part 12. Accordingly, the accuracy of detecting the relative position can be improved based on the difference between the intensity of the first light and the intensity of the second light.

[0138] As a light source having a narrow distribution width, for example, there is a laser light source. Since the laser light source has a small light-emitting point, light can be effectively made incident on the optical fiber. As the laser light source, for example, a semiconductor laser can be used. The semiconductor laser has the advantages of being small-sized and having a low driving voltage. Also, as the laser light source, a gas laser light source or a diode-pumped solid-state laser (DPSS) can be used. These laser light sources have the advantages of having a narrow line width and being easy to stabilize the peak wavelength. Also, as the laser light source, a fiber laser can be used. The fiber laser has the advantage of being easy to couple with an optical fiber. In particular, although it is difficult to connect a single-mode optical fiber to a light source that emits light into free space, it is easy to connect if it is a fiber laser. Since the present disclosure is not affected by the oscillation principle of the laser, a person who implements the present disclosure can freely select a laser light source.

[0139] As another light source having a narrow spectral width, a light-emitting tube having a line spectrum based on atomic transitions such as a high-pressure mercury lamp can also be used. However, in the implementation of the present disclosure, a laser light source or a light-emitting tube is not essential, and thus a light-emitting diode or the like can also be used.

[0140] In this embodiment, as Figure 1As shown, the light source unit 20 includes laser elements 21a and 21b, optical systems 22a and 22b, and a light combining element 23. The laser element 21a is an example of a first laser light source that emits first light, and is, for example, a semiconductor laser. The laser element 21b is an example of a second laser light source that emits second light, and is, for example, a semiconductor laser.

[0141] The optical system 22a is an optical element for making the light emitted from the laser element 21a enter the light combining element 23. The optical system 22b is an optical element for making the light emitted from the laser element 21b enter the light combining element 23. The light combining element 23 is, for example, a wavelength combiner or a dichroic optical element, etc. Accordingly, the optical paths of the first light and the second light can be unified and enter the optical fiber 17. In addition, the coincidence of the optical paths can be performed in free space or in a fiber element. In addition, the light source unit 20 may not include the optical systems 22a and 22b and the light combining element 23.

[0142] [Light intensity measurement unit]

[0143] The light intensity measurement unit 30 measures the intensity of each of the first reflected light and the second reflected light incident on the light incident point 122. Specifically, the light intensity measurement unit 30 independently measures the intensity of light of the first wavelength λ 1 and the intensity of light of the second wavelength λ 2 . Alternatively, the light intensity measurement unit 30 may measure the intensity ratio of the light of the first wavelength λ 1 to the light of the second wavelength λ 2 , or may measure the intensity difference between the light of the first wavelength λ 1 and the light of the second wavelength λ 2 .

[0144] For example Figure 1 as shown, the light intensity measurement unit 30 includes photodetectors 31a and 31b, a light separation element 32, and AD conversion circuits 33a and 33b.

[0145] The light separation element 32 separates the first reflected light and the second reflected light incident on the light incident point 122 and transmitted through the optical fibers 16 and 18. The light separation element 32 is, for example, an optical fiber beam splitter. In the present embodiment, since the first wavelength λ 1 is separated from the second wavelength λ 2 , they can be simply separated. Alternatively, the light separation element 32 may also be a dichroic mirror or a dichroic cube. And the light separation element 32 may also be a diffraction grating or a prism, etc.

[0146] Alternatively, the optical separation element 32 may include an optical fiber separator, a beam splitter, or the like that divides light at a specific intensity ratio regardless of the wavelength. Accordingly, an optical filter may also be configured to allow only the first wavelength λ 1 or the second wavelength λ 2 to pass through in two optical paths.

[0147] The optical detector 31a is an example of a first photodiode that photoelectrically converts the first reflected light to output a first signal. The AD conversion circuit 33a is an example of a first circuit that performs analog-to-digital conversion on the first signal output from the optical detector 31a. The AD conversion circuit 33a outputs the first signal converted into a digital signal to the control unit 14.

[0148] The optical detector 31b is an example of a second photodiode that photoelectrically converts the second reflected light to output a second signal. The AD conversion circuit 33b is an example of a second circuit that performs analog-to-digital conversion on the second signal output from the optical detector 31b. The AD conversion circuit 33b outputs the second signal converted into a digital signal to the control unit 14.

[0149] In addition, the AD conversion function performed by the AD conversion circuits 33a and 33b may also be provided in the control unit 14. The configuration of the light intensity measurement unit 30 is not limited to the Figure 1 example.

[0150] Thus, in the present embodiment, the light intensity measurement unit 30 can be implemented with a simple configuration including two optical detectors (e.g., two photodiodes) 31a and 31b and two AD conversion circuits 33a and 33b. Assuming that white light is split using a diffraction grating, a prism, or the like and spectral measurement is performed using an array detector, it is difficult to provide an AD converter for each photodiode of the array detector. For this reason, since it is necessary to switch and use a limited number of AD converters, it is difficult to calculate the relative position in a short period.

[0151] In the present embodiment, it is only necessary to measure the intensities of only the two wavelengths, the first wavelength λ 1 and the second wavelength λ 2 . Therefore, the relative position between the movable part 11 and the movable part 12 can be calculated in a short period, and thus the relative position can be controlled.

[0152] In addition, in the Figure 1 example shown, although the two optical detectors 31a and 31b are each connected to the AD conversion circuits 33a and 33b, it is not limited thereto. It may also be as in Figure 2As in the light intensity measurement unit 30A of the measurement device 1A shown, a differential operation circuit 34 is connected to two photodetectors 31a and 31b. Here, Figure 2 The schematic configuration of the measurement device according to the modified example of the present embodiment is shown.

[0153] The differential operation circuit 34 receives the input of the first signal output from the photodetector 31a and the second signal output from the photodetector 31b. The differential operation circuit 34 calculates the difference between the first signal and the second signal, and sends the signal indicating the calculated difference to the control unit 14. The differential operation circuit 34 is realized by a differential amplifier circuit such as an operational amplifier.

[0154] [Interferometer]

[0155] The interferometer 40 measures the position of the mirror 113 of the movable part 11 of the probe 10 using the light L. The mirror 113 is fixed at a position opposite to the probe head 111. Since the position of the probe head 111 in contact with the measurement object changes along the shape of the measurement object, the shape of the measurement object can be measured by measuring the position of the mirror 113.

[0156] The interferometer 40 is used as a light source for the light L for measuring, for example, a wavelength-stabilized He-Ne laser or a frequency-stabilized semiconductor laser. In addition, the probe 10 may independently include a mirror for reflecting the light L for the interferometer 40 and a mirror for reflecting the light for measuring the relative position between the movable part 11 and the movable part 12.

[0157] [Control method for the relative position between the movable part 11 and the movable part 12]

[0158] Next, a control method for the relative position between the movable part 11 and the movable part 12 will be described.

[0159] After the first light and the second light emitted from the light source unit 20 are transmitted through the optical fiber 17, the optical circulator 19, and the optical fiber 16, they are emitted from the end portion 161 as the light emission point 121. The first light and the second light emitted from the end portion 161 of the optical fiber 16 are converted into parallel light by the collimating lens 123 and propagate in the probe housing 120b. Specifically, the parallel light from the collimating lens 123 is reflected by the optical element 129 and then incident on the condenser lens 125.

[0160] Through the condenser lens 125, the first light and the second light, which are parallel lights, are transformed into lights converged near the mirror 113 and reflected by the mirror 113. The reflected lights (i.e., the first reflected light and the second reflected light) reflected by the mirror 113 pass through the condenser lens 125 again to become parallel lights, propagate within the probe housing 120b, and after being incident on the collimating lens 123 again, are converged to a region near the end 161 of the optical fiber 16.

[0161] The paths of the first light and the second light vary depending on the relative positions of the condenser lens 125 provided in the movable part 12 and the mirror 113 provided in the movable part 11. That is, the paths of the first light and the second light depend on the relative positions of the movable part 11 and the movable part 12.

[0162] Through the collimating lens 123, the closer the light is converged to the region near the end 161 of the optical fiber 16, the more light enters the interior of the optical fiber 16. Therefore, the light intensity measured by the light intensity measurement unit 30 is higher. The position where the light is converged by the collimating lens 123 depends on the relative positions of the condenser lens 125 and the mirror 113.

[0163] Therefore, for example, by controlling the movable part 12 so that the intensity of the first light measured by the light intensity measurement unit 30 always remains maximum, the relative positions of the movable part 11 and the movable part 12 can be kept unchanged.

[0164] At this time, when only the intensity of the first light is used, when the intensity is not maximum, it is impossible to determine in which direction the movable part 12 should be driven. Thus, in the measuring device 1 according to the present embodiment, not only the first light but also the second light having a different peak wavelength is used.

[0165] Here, the first light and the second light exit from the end 161 of the optical fiber 16 and are converged as the first reflected light and the second reflected light at the end 161 of the optical fiber 16. The optical system in such a path has at least one different optical power with respect to the first wavelength λ 1 and the second wavelength λ 2 . With this configuration, it is possible to change the relative positions of the movable part 11 and the movable part 12 when the intensity of the first wavelength λ 1 detected by the light intensity measurement unit 30 becomes maximum, and the relative positions of the movable part 11 and the movable part 12 when the intensity of the second wavelength λ 2 detected by the light intensity measurement unit 30 becomes maximum.

[0166] Figure 3 Shows the relationship between the relative positions of the two movable parts and the light intensity. Specifically, Figure 3This is a schematic diagram showing the relative positions of the mirror 113 of the movable part 11 and the condenser lens 125 of the movable part 12, and the relationship between the intensities of the first light and the second light. The light intensities of the first light and the second light respectively reach their maxima at the relative positions where the end 161 as the light emission point 121 and the end 161 that becomes the light incident point via the optical system are optically conjugate. As Figure 3 shown, since the optical power of at least one optical element in the optical system is different for the first wavelength λ 1 and the second wavelength λ 2 , the relative positions at which the intensity of the first wavelength λ 1 reaches its maximum and the relative positions at which the intensity of the second wavelength λ 2 reaches its maximum are different.

[0167] In addition, Figure 3 it shows a case where the optical power for the first wavelength λ 2 is greater than the optical power for the second wavelength λ 1 compared with the condenser lens 125. That is, compared with the focal length of the condenser lens 125 at the first wavelength λ 1 , the focal length of the condenser lens 125 at the second wavelength λ 2 is shorter. Therefore, compared with the relative position that becomes conjugate at the first wavelength λ 1 , it becomes conjugate at a shorter relative position at the second wavelength λ 2 .

[0168] For example, in the case of controlling the relative position so that the intensity of the light at the first wavelength λ 1 reaches its maximum, when the intensities of the light at the first wavelength λ 1 and the light at the second wavelength λ 2 both decrease, the control unit 14 controls the drive mechanism 13 so that the relative positions of the movable part 11 (specifically, the mirror 113) and the movable part 12 (specifically, the condenser lens 125) approach each other. And, when the intensity of the light at the first wavelength λ 1 decreases and the intensity of the light at the second wavelength λ 2 increases, the control unit 14 controls the drive mechanism 13 so that the relative positions of the movable part 11 and the movable part 12 move away from each other. Accordingly, the relative positions of the movable part 11 and the movable part 12 can be maintained within a certain range.

[0169] Alternatively, the control unit 14 may be based on the intensity of the light at the first wavelength λ 1 and the intensity of the light at the second wavelength λ 2The difference in the intensity of light is used to control the drive mechanism 13. For example, the control unit 14 controls the drive mechanism 13 in such a way that the relative position where the difference in intensity becomes 0 is maintained. In this case, when the difference in intensity is positive, the control unit 14 controls the drive mechanism 13 to make the relative position of the movable part 11 and the movable part 12 closer. When the difference in intensity is negative, the control unit 14 controls the drive mechanism 13 to make the relative position of the movable part 11 and the movable part 12 farther away. Accordingly, the relative position of the movable part 11 and the movable part 12 can be maintained within a certain range. This control is an example, and other controls can also be performed.

[0170] In addition, it is desired that the relative position of the movable part 11 and the movable part 12 be controlled to be the position where the interferometer 40 can perform the best measurement. In the case where the light L used by the interferometer 40 is condensed by the condenser lens 125 and reflected by the mirror 113, the control is performed such that the mirror 113 is arranged at the focal position of the condenser lens 125 at the wavelength of the light L used by the interferometer 40.

[0171] This is achieved by setting the focal length of the condenser lens 125 at one of the wavelengths of the first wavelength λ 1 and the second wavelength λ 2 to be almost equal to the focal length of the condenser lens 125 at the wavelength (third wavelength) λ 3 of the light L used by the interferometer 40, so that the detection intensity of the light L with almost equal wavelengths can be maximized by controlling the relative position.

[0172] There are the following two methods to make the focal length of the condenser lens 125 at the wavelength λ 3 of the light L used by the interferometer 40 almost equal to the focal length of the condenser lens 125 at one of the first wavelength λ 1 and the second wavelength λ 2 .

[0173] The first method is to make the wavelengths themselves close.

[0174] One of the first wavelength λ 1 and the second wavelength λ 2 is set to be close to the wavelength λ 3 of the light L used by the interferometer 40. In this case, the focal length of the condenser lens 125 in the probe 10 for the wavelength λ 3 of the light L used by the interferometer 40 is close to the focal length for one of the first wavelength λ 1 or the second wavelength λ 2 . For example, the wavelength λ 3 is made close to the first wavelength λ 1or the second wavelength λ 2 The difference between one of them is set to be 5 nm or less when the wavelength λ 3 is less than 500 nm, and 10 nm or less when it is 500 nm or more. The wavelength λ 3 can be equal to one of the first wavelength λ 1 or the second wavelength λ 2 .

[0175] When the first light or the second light is incident on the interferometer 40, there may be a case where it has an adverse effect on the measurement of the object to be measured. Also, when the light L used by the interferometer 40 is incident on the light intensity measurement unit 30, there may be a case where it has an adverse effect on the measurement of the relative position between the movable part 11 and the movable part 12.

[0176] Therefore, in order to avoid the incidence of unwanted light, the movable part 12 can be provided with a mechanism that does not allow unwanted light to enter. This mechanism can be provided in the condenser lens 125 or the optical element 129, or can be provided as an optical element different from the condenser lens 125 or the optical element 129. For example, when the polarization states of the first light and the second light are different from the polarization state of the light L used by the interferometer 40, a polarization optical element can be used to transmit one light and block the other light.

[0177] Or it can also be that the wavelength λ 3 of the light L used by the interferometer 40 1 and the first wavelength λ 2 or the second wavelength λ do not need to be exactly the same and can have a slight deviation. For example, due to the selection of the optical glass material of the lens and the design of the shape, if the wavelength difference is about 10 nm, the focal lengths are almost the same. More specifically, a lens with a focal length difference within 5% can be designed.

[0178] Also, in a filter using a dielectric multilayer film, it is easy to form a band-pass filter with a pass width of 10 nm or less or a notch filter with a rejection width of 10 nm or less. For example, a band-pass filter that allows the wavelength λ 3 of the light L used by the interferometer 40 to pass through and blocks the first wavelength λ 1 and the second wavelength λ 2 can be arranged on the optical path toward the interferometer 40, and a notch filter that blocks the wavelength λ 3 of the light L used by the interferometer 40 and allows the first wavelength λ 1 and the second wavelength λ 2 to pass through can be arranged on the optical path toward the light intensity measurement unit 30. Accordingly, for the interferometer 40 and the light intensity measurement unit 30, each can avoid the mixing of unwanted light.

[0179] The second method is to use a lens having the same focal length at multiple wavelengths.

[0180] A lens formed by combining multiple optical glass materials with different refractive index distributions can have the same focal length for multiple wavelengths. As an example, the wavelength dependence of the focal length of an achromatic lens combining two optical glass materials is given by Figure 4 shown. Figure 4 The relationship between the wavelength of the incident light and the focal length of the achromatic lens is shown. For example, an achromatic lens having the Figure 4 shown characteristics is used as the condenser lens 125.

[0181] The focal length of the achromatic lens shows characteristics having substantially one pole with respect to the wavelength. For this reason, outside the focal length at the pole, there are two wavelengths having the same focal length. At this time, one wavelength is set as the wavelength λ 3 of the light L used by the interferometer 40, and the other wavelength is set as the wavelength of the first light or the second light. Accordingly, the focal lengths of the condenser lens 125 can be made almost the same for one of the wavelength λ 3 and the first wavelength λ 1 or the second wavelength λ 2 , and the wavelengths of each other can be made quite different.

[0182] In the Figure 4 example, it is shown that the first wavelength λ 1 is a wavelength having the same focal length as the wavelength λ 3 of the light L used by the interferometer 40, and the focal length at the second wavelength λ 2 is relatively short. Of course, other combinations are also possible. For example, the focal length at the second wavelength λ 2 can also be longer than the focal length at the wavelength λ 3 of the light L used by the interferometer 40.

[0183] When using an achromatic lens, since the wavelengths can be made quite different, the separation of the light passing through the dichroic mirror or the dielectric multilayer film filter becomes easy. For example, when both the first wavelength λ 1 and the second wavelength λ 2 are selected to be shorter or longer than the wavelength λ 3 of the light L used by the interferometer 40, the separation of the light L used by the interferometer 40 from the first light and the second light by the dichroic mirror becomes easy.

[0184] In addition, the focal length at the wavelength λ 3 of the light L used by the interferometer 40 does not need to be the same as the focal length at the first wavelength λ 1 or the second wavelength λ 2The focal lengths are exactly the same. As long as the difference in focal lengths is very small, the effect can be obtained. Specifically, for wavelength λ 3 The optical power of the optical element at wavelength λ 1 or λ 2 should be almost equal to the optical power of this optical element at that wavelength.

[0185] [Regarding the effect]

[0186] Next, regarding the effect of the measuring device 1 according to this embodiment, an explanation will be given while comparing it with Figure 6 the conventional optical probe 10x shown.

[0187] Specifically, in the conventional example, in order to measure the relative positions of the movable part 11x and the movable part 12x, a semiconductor laser 21x, two photodetectors 31ax and 31bx, a beam splitter, and two pinholes were provided in the movable part 12x. In contrast, in the measuring device 1, instead of the above configuration, the end 161 of the optical fiber 16 is connected to the movable part 12. The advantages of this configuration will be described below.

[0188] The first advantage is the miniaturization and weight reduction of the movable part 12.

[0189] Generally, the semiconductor laser 21x is housed in a package having a metal housing and a glass window with a size of about several mm in order to suppress deterioration caused by air or the like. However, at the end 162 of the optical fiber 16 serving as the light emission point 121, a metal housing and a glass window are not required. Therefore, by making this omission, the movable part 12 can be made lighter.

[0190] Regarding the size, as long as it is the optical fiber 16, the diameter of the end 161 can be made less than 1 mm. Therefore, the end 162 of the optical fiber 16 can be used as the light emission point 121 instead of the semiconductor laser 21x, and thus the size of the movable part 12 can be reduced.

[0191] Moreover, the optical fiber 16 has high symmetry and emits light from a small-diameter circular cross-section. Especially for single-mode optical fibers, the cross-section is very small. For this reason, the optical fiber 16 can emit light with a unified spatial mode. Therefore, by using a small and lightweight lens with a short focal length as the collimating lens 123, the light emitted from the optical fiber 16 is converted into a collimated beam with a small diameter, and beam divergence can also be suppressed.

[0192] If the diameter of the light can be reduced, each component such as a lens, a prism, and a mirror included in the optical system fixed to the movable part 12 can be made smaller. Therefore, the entire optical system can be miniaturized and lightened, which contributes to the miniaturization of the movable part 12.

[0193] In addition, the optical system of the movable part 12 may also include a GRIN (Graded-Index) lens fixed to the end 161 of the optical fiber 16. By adopting the GRIN lens, the collimating lens 123 can be omitted, and thus the movable part 12 can be further miniaturized and lightened.

[0194] Light with a unified spatial mode can be focused into a smaller range. This means that a component with a small aperture can be used as the pinhole for detecting the relative position between the movable part 11 and the movable part 12. Or it means that the focal length of the lens that focuses light onto the pinhole can be reduced. Therefore, this also contributes to the miniaturization and lightening of the movable part 12.

[0195] However, the semiconductor laser 21x as a conventional light source has spatial diffusivity and emits light asymmetrically in the vertical and horizontal directions. Therefore, divergence is likely to occur in a collimated light beam with a small diameter, making it difficult to miniaturize optical systems such as lenses.

[0196] And the same as in the case of the semiconductor laser 21x, the optical detectors 31ax and 31bx also need to be about several millimeters in diameter for sealing. In this regard, in the present embodiment, the optical detectors 31a and 31b are separately arranged from the movable part 12, and the end 161 of the optical fiber 16 is connected to the movable part 12. In this respect, the movable part 12 can also be miniaturized and lightened. And in the present embodiment, a light-shielding component having a pinhole can be omitted. Therefore, further miniaturization and lightening can be achieved.

[0197] The second advantage is the reduction of wiring.

[0198] When operating the semiconductor laser 21x, different wires are required for the anode and cathode respectively to connect to the power supply. That is, at least two wires are required to connect to the semiconductor laser 21x fixed to the movable part 12. Generally speaking, if the output display installed inside the semiconductor laser 21x is also utilized, another wire is also required. The same applies to the optical detectors 31ax and 31bx, and power supply wires and signal wires are required. The more wires connected to the movable part 12, the more difficult it is to miniaturize the movable part 12.

[0199] In this regard, in the present embodiment, the light source unit 20 and the light intensity measurement unit 30 are separately provided from the movable part 12. Only one optical fiber 16 for light emission needs to be connected to the movable part 12. Therefore, the miniaturization of the movable part 12 can be achieved.

[0200] The third advantage is the reduction of heat generation.

[0201] In semiconductor laser 21x, usually less than half of the consumed power is converted into light. The remaining power is released as heat. The heat discharged from semiconductor laser 21x fixed to movable part 12 causes the temperature inside movable part 12 to rise. The rise in the temperature inside movable part 12 causes the refractive index of the air inside to change, that is, air fluctuations occur. Since light L of the distance measurement mechanism for measuring the shape of the object to be measured also passes through the inside of movable part 12, this fluctuation has an adverse effect on the accuracy of measuring the shape of the object to be measured.

[0202] In this regard, in the present embodiment, a light source unit 20 that becomes a main heat source is not provided in movable part 12. The heat generated in the part of optical fiber 16 connected to movable part 12 that is fixed to movable part 12 can be almost ignored. Therefore, the influence caused by heat can be greatly reduced, and thus the reduction in the measurement accuracy of the object to be measured can be suppressed.

[0203] The fourth advantage is easy replacement.

[0204] Generally speaking, the lifespan of semiconductor laser 21x is about 10,000 hours. This lifespan is about one year when it is constantly lit. When semiconductor laser 21x deteriorates, it becomes difficult to measure the relative position between movable part 11 and movable part 12. Therefore, it is necessary to replace semiconductor laser 21x.

[0205] When semiconductor laser 21x is fixed to movable part 12, each time replacement is carried out, adjustment work of the optical system fixed to movable part 12 needs to be performed. Since a part of the optical system of movable part 12 is also shared in interferometer 40 for measuring the shape of the object to be measured, careful attention is required during adjustment.

[0206] However, in the present embodiment, laser element 21 and movable part 12 are arranged separately. In this case, even if laser element 21 needs to be replaced, only the adjustment of the optical system combined with optical fiber 16 needs to be performed. Therefore, the replacement adjustment work can be made easy.

[0207] (Embodiment 2)

[0208] Next, Embodiment 2 will be described. In the measuring device according to the present embodiment, a light source that can simultaneously generate first light and second light is used as the light source unit.

[0209] Figure 5 The schematic configuration of the measuring device according to the present embodiment is shown. As Figure 5As shown, compared with the measuring device 1 in the first embodiment, the measuring device 2 is provided with a light source unit 20A instead of the light source unit 20. The other configurations are the same as those in the first embodiment. Hereinafter, the description of the common parts will be omitted, and the description will be centered on the differences from the first embodiment.

[0210] The light source unit 20A includes a laser element 21 and an optical system 22. The laser element 21 is an example of a light source that generates the first light and the second light simultaneously. Specifically, the laser element 21 is an example of a laser light source including a first active region that emits the first light and a second active region that emits the second light. The optical system 22 is an element that makes the first light and the second light emitted from the laser element 21 enter the optical fiber 17. For example, the optical system 22 is a condenser lens. The optical system 22 can be a filter that only transmits a desired wavelength.

[0211] For example, the laser element 21 is a semiconductor laser that can oscillate multiple wavelengths simultaneously. As the laser element 21, for example, a dual-wavelength laser for CD-DVD can be used. The dual-wavelength laser for CD-DVD forms a first active region that oscillates at about 650 nm and a second active region that oscillates at about 780 nm in one chip. Although the positions of the active regions that emit light of each wavelength are spatially separated, for a multimode optical fiber, it is relatively easy to make the light of both enter the same core through one optical system.

[0212] In addition, as a light source that can generate the first light and the second light simultaneously, it is not limited to semiconductor lasers.

[0213] A gas laser light source can also be used instead of the laser element 21. For example, a gas laser such as an Ar laser has multiple discrete oscillation wavelengths. Therefore, by carefully designing the resonator, etc., multiple wavelengths can be made to oscillate simultaneously. For example, there is a well-known multi-wavelength Ar laser that can simultaneously oscillate light of 457 nm, 488 nm, and 514 nm. Two desired wavelengths can also be selected from these wavelengths for use. Of course, two desired wavelengths of a multi-wavelength gas laser with other oscillation wavelengths can also be selected.

[0214] Moreover, instead of the laser element 21, a gas discharge lamp can also be used. The gas discharge lamp has multiple discrete bright lines. For example, a high-pressure mercury lamp has strong bright lines at 405 nm and 436 nm respectively. By using an optical filter, a prism, a diffraction grating, etc., light with a specific wavelength can be extracted.

[0215] [Modification Example]

[0216] In Embodiment 2, although an example in which one light source simultaneously generates the first light and the second light is shown, as a method for generating light having other wavelength spectra from one light source, there is a method using fluorescence.

[0217] Fluorescence is a phenomenon in which a phosphor is excited by a certain wavelength and emits light with a longer wavelength. Examples of phosphors include organic molecules such as aromatic compounds, direct-transition type semiconductors, quantum dots including these, glasses or crystals including rare earths, etc. Among the above, phosphors using quantum dots and phosphors including rare earths are effectively used in the measurement device of the present disclosure because of the narrow spectral width of fluorescence. However, even light with a wide spectral width can be implemented by the measurement device of the present disclosure. And a band-pass filter or the like can be used to narrow the spectral width.

[0218] The generation of fluorescence using a phosphor can also be performed in free space. Or it can be that wavelength conversion is performed in an optical fiber having a core or a cladding containing a phosphor. In the configuration in which wavelength conversion is performed in an optical fiber, it is not necessary to make two lights incident on one core respectively, so the device configuration and adjustment become simple.

[0219] Moreover, wavelength conversion means other than phosphors can also be adopted. For example, nonlinear optical crystals can be used, and based on a phenomenon such as SHG (second harmonic generation), light of other wavelengths can be generated based on light of a certain wavelength. Or it can be that based on a combination of lights of two or more wavelengths, light of other wavelength groups can be generated by SFG (sum frequency generation). Or it can be that by using OPO (optical parametric oscillation), light of one wavelength is split into two, and thus two lights of different wavelengths can be obtained. Regarding nonlinear optical crystals, for example, as long as it is waveguide-type PPLN (periodically poled lithium niobate) or the like, it can be easily arranged on an optical fiber path.

[0220] (Other Embodiments)

[0221] The measurement device related to one or more embodiments has been described above based on the embodiments, but the present disclosure is not limited to the above embodiments. Within the scope not departing from the gist of the present disclosure, forms obtained by performing various modifications conceivable by those skilled in the art on the present embodiment, and forms constructed by combining constituent elements in different embodiments are all included in the scope of the present disclosure.

[0222] For example, in the measuring device according to each embodiment, the movable part 11 and the movable part 12 may not be connected at all. The weight of the movable part 11 may be used to change the relative position of the movable part 11 and the movable part 12 in the vertical direction. In this case, by adjusting the posture of the measuring device to align the vertical direction with the plumb line direction, the weight of the movable part 11 can be effectively utilized. In addition, in order to prevent the movable part 11 from detaching from the movable part 12, a restricting part such as a protrusion for restricting the position of the movable part 11 may be provided.

[0223] Moreover, although an example is shown in which the light incident point and the light exit point are the same and are the end of one optical fiber, it is not limited thereto. The light incident point and the light exit point may also be different. For example, the end of the first optical fiber as the light incident point and the end of the second optical fiber as the light exit point may be respectively connected to the movable part 12.

[0224] Furthermore, the present disclosure can be implemented as a control system or a control method for a movable body included in a measuring device. The control system is implemented by, for example, one or more computer devices. Specifically, the control system includes a control unit that controls a drive mechanism that adjusts the position of a second movable body having a light exit point, a light incident point, and an optical system. The first light and the second light emitted from the light exit point are irradiated onto a reflector included in the first movable body via the optical system. The first reflected light and the second reflected light reflected from the reflector are respectively incident on the light incident point via the optical system. The control unit controls the drive mechanism based on the intensities of the first reflected light and the second reflected light incident on the light incident point, thereby adjusting the position of the second movable body. The first wavelength, which is the peak wavelength of the first light, is different from the second wavelength, which is the peak wavelength of the second light. The optical power of the optical system at the first wavelength is different from the optical power of the optical system at the second wavelength.

[0225] Furthermore, the present disclosure can also be implemented as a non-contact measuring device. Specifically, when measuring a measurement object, the first movable body of the measuring device may not contact the measurement object. For example, an interferometer may be configured to irradiate light onto the surface of the measurement object and receive the reflected light of the light from the measurement object.

[0226] In addition, one or more computer devices include, for example, a non-volatile memory storing a program, a volatile memory that is a temporary storage area for executing the program, an input / output port, a processor for executing the program, and the like. Moreover, the control system may be a programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor in which the connection and setting of circuit units in an LSI can be reconfigured. The functions executed by the control system can be implemented by software or by hardware.

[0227] Moreover, a control method for a movable body included in a measuring device includes a step of controlling a drive mechanism that adjusts the position of a second movable body having a light emission point, a light incidence point, and an optical system. First light and second light emitted from the light emission point are irradiated onto a reflector included in the first movable body via the optical system. First reflected light and second reflected light reflected from the reflector are each incident on the light incidence point via the optical system. In the step of performing control, the drive mechanism is controlled based on the intensities of the first reflected light and the second reflected light incident on the light incidence point, whereby the position of the second movable body is adjusted. A first wavelength that is the peak wavelength of the first light is different from a second wavelength that is the peak wavelength of the second light. The optical power of the optical system at the first wavelength is different from the optical power of the optical system at the second wavelength.

[0228] Moreover, the present disclosure can be implemented as a program that causes a computer to execute the control method for the movable body included in the measuring device. Moreover, the present disclosure can be implemented as a non-transitory recording medium that stores the program.

[0229] Moreover, the above-described embodiments can be variously changed, replaced, added, omitted, etc. within the scope of the claims or an equivalent thereof.

[0230] Industrial Applicability

[0231] The present disclosure can be used in various measuring devices such as inspection of industrial products that require high-precision distance measurement.

Claims

1. A measuring device, The measuring device comprises: a first movable body having a reflector; A second movable body, the second movable body having a light exit point, a light incident point and an optical system; A driving mechanism for adjusting the position of the second movable body; and A control unit controls the driving mechanism. The first light and the second light emitted from the light exit point are irradiated onto the reflector via the optical system. A first reflected light and a second reflected light are respectively incident on the light incident point via the optical system, the first reflected light being the reflected light of the first light from the reflector, and the second reflected light being the reflected light of the second light from the reflector, The control unit controls the driving mechanism according to the respective intensities of the first reflected light and the second reflected light incident on the light incident point, thereby adjusting the position of the second movable body. The first wavelength is different from the second wavelength, the first wavelength is the peak wavelength of the first light, and the second wavelength is the peak wavelength of the second light, The optical power of the optical system at the first wavelength is different from the optical power of the optical system at the second wavelength.

2. The measuring device according to claim 1, The measuring device comprises an optical fiber, The light exit point and the light incident point are both the first end of the optical fiber.

3. The measuring device according to claim 1, The wavelength components of the first light and the second light having intensities greater than or equal to a predetermined value do not overlap with each other.

4. The measuring device according to any one of claims 1 to 3, Light used in measuring an object is incident on the optical system. a third wavelength which is different from both the first wavelength and the second wavelength, and is a peak wavelength of light used in measuring the object; The optical power of the optical system at the third wavelength is substantially equal to one of the optical power of the optical system at the first wavelength and the optical power of the optical system at the second wavelength, but different from the other.

5. The measuring device according to claim 4, The measuring device includes an interferometer that causes interference of light used for measuring the object.

6. The measuring device according to any one of claims 1 to 3, The measuring device includes a light intensity measuring unit configured to measure the intensity of each of the first reflected light and the second reflected light incident on the light incident point.

7. The measuring device according to claim 6, The light intensity measuring unit comprises: a first photodiode, performing photoelectric conversion on the first reflected light and outputting a first signal; a second photodiode, performing photoelectric conversion on the second reflected light and outputting a second signal; A first circuit performs analog-to-digital conversion on the first signal; as well as The second circuit, different from the first circuit, performs analog-to-digital conversion on the second signal.

8. The measuring device according to claim 6, The light intensity measuring unit comprises: a first photodiode, performing photoelectric conversion on the first reflected light and outputting a first signal; a second photodiode, performing photoelectric conversion on the second reflected light and outputting a second signal; as well as The differential operation circuit receives inputs of the first signal and the second signal.

9. The measuring device according to claim 2, The measuring device comprises a light source unit, The light emitted from the light source enters the end of the optical fiber on the opposite side to the first end, propagates through the optical fiber, and is emitted from the first end as the first light and the second light.

10. The measuring device according to claim 9, The light source unit comprises: A first laser light source, emitting the first light; as well as The second laser light source, different from the first laser light source, emits the second light.

11. The measuring device according to claim 9, The light source section is a laser light source including a first active region that emits the first light and a second active region that emits the second light.

12. The measuring device according to claim 9, The light source unit is a gas laser light source that emits the first light and the second light.

13. The measuring device according to any one of claims 1 to 3, The optical system includes an achromatic lens.

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