Optical devices

Abstract

To prevent, by a simple structure, a force in the optical axis direction from being applied to an optical component and suppress the displacement in the optical axis direction to enable precise positioning when fixing the optical axial position of the optical component.SOLUTION: In an optical device provided with a position adjustment fixing device for an optical component (30) of the optical device for adjusting and fixing the optical axial position of the optical component (30), the position adjustment fixing device comprises an elongated hole 34, formed on a side face of the optical component (30), which is long in the optical axis direction, a fixing jig 50 attached to fixing objects (22, 80) of the optical component (30) and capable of moving along the elongated hole 34, a non-penetrating screw hole 54 formed in the fixing jig 50 and divided by a screw slotting 52, and a fixing screw 60 that screws into the screw hole 54 and pushes the screw slotting 52 to expand it when screwed thereinto, causing the outside face of the fixing jig 50 to be pressure contacted with the inside face of the elongated hole 34.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an optical device, and more particularly to an optical device suitable for use in a Mirau-type or Michelson-type white light interferometer used in an image measuring instrument, a measuring microscope, or the like. [Background technology]

[0002] As shown in Figure 1, which illustrates the main configuration of a Mirau-type white light interferometer, non-contact surface shape measurement using a white light interferometer optical head 10, as described in Patent Documents 1 to 5, etc., involves splitting light emitted from a white light source 12 using a beam splitter 16 and a half mirror 18 into reference light directed to a reference mirror 20 and measurement light directed to the surface of a measurement target such as a measurement workpiece W. Interference fringe images generated by the optical path difference between the light reflected from each light source are observed by a camera 26 including a light-receiving element array, and the uneven shape of the measurement workpiece W, etc. is measured based on the intensity of the interference fringes. In the figure, reference numeral 14 denotes a collimating lens, 22 denotes an interference objective lens (hereinafter simply referred to as the objective lens), 24 denotes an imaging lens, and 30 denotes an interference unit for adjusting the position of the reference mirror 20 up and down to generate interference fringes.

[0003] When the white light interferometer optical head 10 is scanned perpendicularly to the surface of the measurement workpiece W, interference fringes are generated around the position where the optical path difference between the reference light and the measurement light is 0. By detecting the peak position of the intensity of these interference fringes with the light receiving element of the camera 26, the three-dimensional surface shape of the measurement workpiece W (hereinafter also simply referred to as the three-dimensional shape) can be obtained.

[0004] White light interferometers include not only the Mirau type, in which the optical axis of the objective lens 22 and the optical axis of the reference mirror 20 are coaxial, as shown in FIG. 1, but also the Michelson type, as described in Patent Documents 5 and 6, in which the optical axis of the objective lens 22 and the optical axis of the reference mirror 20 are perpendicular to each other, as shown in FIG. 6(A) below.

[0005] In such a white light interferometer, when the focus is on the surface of the measurement workpiece W, the position of the interference unit 30 must be adjusted in the optical axis direction and fixed to the objective lens body so that the distances h1 and h2 are equal and the focus is on the reference mirror 20.

[0006] Therefore, various adjustment and fixing methods have been proposed in Patent Documents 7 to 12, but all of them have complicated configurations.

[0007] 2, for example, it is conceivable to provide a plurality of blades 32 facing outward in a direction perpendicular to the optical axis of the interference unit 30, and fix the blades 32 from above and below (left and right in FIG. 2) in the optical axis direction so as to sandwich them with an adjustment ring 42 and a fixing ring 44. That is, it is conceivable to machine taps on the outside of the outer frame 40 of the lens barrel 23 of the objective lens 22 and on the inside of the adjustment ring 42 and the fixing ring 44, turn the adjustment ring 42 to move the reference mirror 20 up and down (left and right in FIG. 2), and fix the blades 32 between the fixing ring 44 and the adjustment ring 42 to fix the interference unit 30. In the figure, reference numeral 46 denotes a spring. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 6508764 [Patent Document 2] Patent Publication No. 2021-9128 [Patent Document 3] Patent No. 6461609 [Patent Document 4] Japanese Patent Application Laid-Open No. 2012-93166 [Patent Document 5] Japanese Patent Application Laid-Open No. 2012-88180 [Patent Document 6] Japanese Patent Publication No. 2020-154167 [Patent Document 7] Japanese Patent Application Laid-Open No. 2009-53339 [Patent Document 8] Japanese Patent Application Laid-Open No. 2011-85655 [Patent Document 9] Patent No. 3342321 [Patent Document 10] Patent No. 4201693 [Patent Document 11] Utility Model Registration No. 2569571 [Patent Document 12] Japanese Patent Application Laid-Open No. 2013-104998 Summary of the Invention [Problem to be solved by the invention]

[0009] However, since white light interferometers require extremely high precision in the positioning accuracy of the interference unit 30, the method of rotating the adjustment ring 42 from above and below the blades 32 and applying force in the optical axis direction where precise positioning is desired to fix the interference unit 30, as shown in Figure 2, causes the interference unit 30 to move in the optical axis direction during fixation, making adjustment and fixation extremely difficult. This type of problem also occurs in optical devices other than white light interferometers when optical components must be fixed precisely.

[0010] The present invention has been made to solve the above-mentioned conventional problems, and its object is to prevent force in the optical axis direction from being applied to an optical component when fixing the position of the optical component in the optical axis direction, suppress displacement in the optical axis direction, and enable precise positioning with a simple configuration. [Means for solving the problem]

[0011] The present invention provides an optical device equipped with a position adjusting and fixing device for an optical component for adjusting and fixing the position of an optical component in an optical axis direction of the optical device, the position adjusting and fixing device comprising: an elongated hole formed on a side surface of the optical component, the elongated hole being long in the optical axis direction; and a fixing member attached to a fixing target of the optical component, the fixing member being movable along the elongated hole. , key long in the optical axis direction And, key and a non-through screw hole formed in the hole and divided by a slot. The screw is screwed into the screw hole, and when screwed in, the slot is expanded, key a fixing screw for pressing the outer surface of the slotted hole against the inner surface of the slotted hole; a through hole for a mounting screw formed in the key, the through hole being aligned with the non-through screw hole in the optical axis direction, for mounting the key to a target object to which the optical component is fixed;The present invention provides an optical device comprising:

[0013] where , the above key A plurality of such elements may be provided in the circumferential direction of the optical component.

[0014] The optical device may be a Mirau-type white light interferometer in which the optical axis of the objective lens, which is the fixed object, and the optical axis of a reference mirror included in the interference unit, which is the optical component, are coaxial.

[0015] The optical device may be a Michelson white light interferometer in which the optical axis of the objective lens, which is the fixed object, and the optical axis of a reference mirror included in the interference unit, which is the optical component, are perpendicular to each other. [Effects of the Invention]

[0016] According to the present invention, with a simple configuration, when fixing the position of an optical component in the optical axis direction, the force applied to the optical component is perpendicular to the optical axis, thereby suppressing displacement in the optical axis direction and enabling precise positioning. [Brief explanation of the drawings]

[0017] [Figure 1] A schematic diagram of the optical path of the optical head of a conventional Mirow-type white light interferometer. [Figure 2] 1A and 1B are a longitudinal cross-sectional view and a cross-sectional view along line BB, respectively, showing an example of a conventional method for fixing an interference unit. [Figure 3] FIG. 1 is a longitudinal cross-sectional view showing a fixing portion of an interference unit in a first embodiment of the present invention applied to a Mirau-type white light interferometer. [Figure 4] 1A is a plan view showing the configuration of a key that is a fixture used in an embodiment, and FIG. 1B is a cross-sectional view taken along line BB. [Figure 5] FIG. 10 is a plan view showing a state in which an interference unit is fixed in the embodiment. [Figure 6]FIG. 10A is a longitudinal cross-sectional view showing a fixed portion of an interference unit in a second embodiment of the present invention applied to a Michelson-type white light interferometer, and FIG. 10B is an enlarged view of a reference optical path portion. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the contents described in the following embodiments. Furthermore, the components in the embodiments described below include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the embodiments described below may be combined as appropriate, or may be selected and used as appropriate.

[0019] The first embodiment of the present invention is an application of the present invention to a position adjusting and fixing device for an interference unit of a Mirau type white interferometer. As shown in FIGS. 3 to 5, in the position adjusting and fixing device for an interference unit of a white interferometer, the position of an interference unit 30, which is an optical component to which a reference mirror 20 is fixed, for generating reference light to be interfered with measurement light reflected on the surface of a measurement object, is adjusted in the optical axis direction of the reference mirror 20 (left and right direction in the drawing) and fixed to a lens barrel 23 of an objective lens 22, which is a fixing object, by adjusting the position of the reference mirror 20 formed on the side of the interference unit 30. 4(B) 。 The interference unit 30 includes a slot 34 that is long in the optical axis direction of the objective lens 22, a cylindrical key 50 with two holes as shown in FIG. 4(A) which is a fixture that is attached to the lens barrel 23 of the objective lens 22 to which the interference unit 30 is fixed and is movable along the slot 34, a non-through screw hole 54 as shown in FIG. 4(B) which is formed in the key 50 and divided by a slot 52, and a fixing screw 60 which screws into the screw hole 54 and spreads the slot 52 when screwed in, thereby pressing the outer surface of the key 50 against the inner surface of the slot 34.

[0020] As shown in detail in Figure 4, the key 50 has a blind screw hole 54 for the fixing screw 60 and a through hole 56 for a mounting screw 70 for attaching the key 50 to the lens barrel 23 of the objective lens 22 formed alongside the blind screw hole 54 for the fixing screw 60.

[0021] In the figure, reference numeral 41 denotes a rotatable adjustment ring disposed outside the interference unit 30. Taps are machined on the inner surface of this adjustment ring 41 and the outer surface of the interference unit 30, so that rotating the adjustment ring 41 moves the interference unit 30 up and down (left and right in FIG. 3). In this case, as shown in FIG. 5, the key 50, together with the elongated hole 34, prevents rotational deviation in the circumferential direction indicated by arrow R about the optical axis when the interference unit 30 moves up and down as indicated by arrow A. Furthermore, the dimension L of the elongated hole 34 in the optical axis direction determines the adjustment stroke for moving the interference unit 30 up and down. In other words, excessive upward movement of the interference unit 30 along the optical axis (to the left in FIG. 5) will result in collision with the main body of the objective lens 22. Conversely, excessive downward movement in the opposite direction of the objective lens 22 (to the right in FIG. 5) will cause it to fall off. However, limiting the adjustment stroke of the interference unit 30 with the elongated hole 34 prevents this.

[0022] When adjusting and fixing the position of the interference unit 30, the key 50 is attached to the lens barrel 23 of the objective lens 22 with the mounting screw 70, and then the interference unit 30 is moved left and right in the figure. When the interference fringes appear at the desired position, the fixing screw 60 is tightened to widen the slot 52 of the key 50 vertically in Figure 5, and the outer surface of the key 50 is pressed against the inner surface of the elongated hole 34 of the interference unit 30, thereby fixing the interference unit 30 to the lens barrel 23 of the objective lens 22. At this time, no force is applied to the interference unit 30 in the optical axis direction of the reference mirror 20 (left and right direction in Figure 3), so the reference mirror 20 can be fixed with high precision without being displaced in the optical axis direction.

[0023] By providing a plurality of keys 50 in the circumferential direction of the interference unit 30, the fixation can be made more reliable.

[0024] Next, a second embodiment of the present invention applied to a position adjusting and fixing device for an interference unit of a Michelson type white light interferometer will be described with reference to FIG.

[0025] In this embodiment, in a Michelson white light interferometer in which the optical axis of the objective lens 22 and the optical axis of the reference mirror 20 are perpendicular to each other as shown in Figure 6(A), a holder 80 for the interference unit 30 holds the interference unit 30, which is equipped with an adjustment ring 41, a key 50, a fixing screw 60, and an attachment screw 70 similar to those in the first embodiment.

[0026] In this embodiment, as in the first embodiment, when the interference unit 30 is moved in the optical axis direction (left and right in Figure 6) and reaches the required position, the fixing screw 60 is tightened to expand the key 50 and press it against the elongated hole 34 of the interference unit 30, thereby fixing the interference unit 30.

[0027] In addition, a Michelson-type white light interferometer requires not only a position adjustment mechanism in the optical axis direction but also a tilt adjustment mechanism.

[0028] In the above embodiment, the present invention is applied to the Mirau-type and Michelson-type white light interferometers, but the application of the present invention is not limited to this, and it can be applied to other interferometers such as laser interferometers, and optical devices in general.

[0029] Furthermore, the shape of the fastener and the method of attaching the fastener are not limited to the key 50 and the attachment screw 70.

[0030] Furthermore, the object to be fixed, such as an objective lens, and the optical component, such as an interference unit, do not need to be separate bodies, and the present invention can also be applied to cases where the optical component is incorporated into the object to be fixed. [Explanation of symbols]

[0031] 20...Reference mirror 22...Objective lens (fixed target) 30...Interference unit (optical component) 34...Slotted hole 41...Adjustment ring 50...Key (fixing device) 52...Slit 54...Non-through screw hole 56...Through hole 60...Fixing screw 70...Mounting screw W: Measurement workpiece

Claims

1. An optical device including an optical component position adjusting and fixing device for adjusting and fixing the position of an optical component of the optical device in the optical axis direction, The position adjustment and fixing device is a slot formed on a side surface of the optical component and extending in the optical axis direction; a key that is attached to a fixing target of the optical component and is movable along the elongated hole and is long in the optical axis direction; a non-through screw hole formed in the key and divided by a slot; a fixing screw that threads into the screw hole and, when screwed in, pushes the slot apart to press the outer surface of the key against the inner surface of the slot; a through hole for a mounting screw formed in the key, the through hole being aligned with the non-through screw hole in the optical axis direction, for mounting the key to a target object to which the optical component is fixed; An optical device comprising:

2. 2. The optical device according to claim 1, wherein a plurality of the keys are provided in the circumferential direction of the optical component.

3. The optical device according to claim 1 or 2, characterized in that the optical device is a Mirau-type white light interferometer in which the optical axis of the objective lens, which is the fixed object, and the optical axis of the reference mirror included in the interference unit, which is the optical component, are coaxial.

4. The optical device according to claim 1 or 2, characterized in that the optical device is a Michelson-type white interferometer in which the optical axis of the objective lens, which is the fixed object, and the optical axis of the reference mirror included in the interference unit, which is the optical component, are perpendicular to each other.

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