JP2007328064A - Optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical device designed so as to ensure high accuracy in retaining lens intervals even in the case where lenses can not be cemented by an adhesive and facilitate its assemblage/and adjustment. <P>SOLUTION: The optical device I includes: a first lens holding frame IB1 in which a first lens G1 is fitted; a second lens holding frame IB2 in which a second lens G2 is fitted; and a base material A holding the first and second lens holding frames integrally. In the optical device 1, the first lens holding frame IB1 is fitted in a fitting part a11 formed in the base material and thereby the first lens G1 is positioned in the base material A. In addition, the second lens holding frame IB2 is fitted in a fitting part b12 formed in the first lens holding frame IB1 and thereby the second lens G2 is positioned in the first lens holding frame IB1. Thus, the second lens G2 is positioned in the base material A via the first holding frame IB1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical device including a plurality of lens holding frames each having a lens assembled thereon and a base material that integrally holds these lens holding frames.

  A typical example of the optical apparatus as described above is an objective lens of an optical microscope. The objective lens has a cylindrical barrel as a base material, and a plurality of lenses corresponding to the magnification are integrally held in the barrel. In objective lenses used in high-performance optical microscopes, each lens is configured as a combination lens that combines correction lenses to reduce aberrations in order to reduce aberrations such as coma, astigmatism, and spherical aberration to the limit. Thus, a plurality of lenses are combined and fixed to a lens fixing hardware, and these lens fixing hardware are configured to be positioned and held by fitting into a lens barrel (see, for example, Patent Document 1).

  In the conventional objective lens, as a means for fixing the lenses to be combined, a structure in which an adhesive is appropriately applied to the optical surface and the lenses are bonded to each other is adopted. It was possible to obtain a relatively large tolerance for eccentricity when a plurality of lenses were incorporated into the lens barrel. Therefore, the conventional objective lens is configured to fix the lenses bonded together with an adhesive to the lens fixing hardware, and to position and hold the plurality of lens fixing hardware formed in this manner on the lens barrel. .

JP 2004-219608 A

  However, in order to obtain a high resolution, for example, an objective lens of an optical microscope having an observation wavelength of deep ultraviolet (DUV: Deep Ultra Violet) having a wavelength λ of λ = 193 nm, λ = 248 nm, or the like is used. When they are joined together, there is a problem that the adhesive causes a chemical reaction due to the ultraviolet rays that pass through the joining surfaces, gradually becoming cloudy and lowering the transmittance.

  On the other hand, in order to avoid the above problems, when trying to adopt a lens configuration that does not use an adhesive, extremely high inter-lens holding accuracy (particularly eccentric accuracy) is required, and machining that satisfies this is extremely difficult. there were. In particular, since it is technically difficult to measure the inner diameter of a thin and long lens barrel with high accuracy, it is extremely difficult to reduce the fitting backlash between the lens barrel and the lens fixing hardware to about 5 μm or less. Thus, it is difficult to obtain the required optical performance by fitting the lens barrel and the lens fixing hardware.

  The present invention has been made in view of the above-described problems of the prior art, and even when the lenses cannot be bonded together with an adhesive, a desired inter-lens holding accuracy can be secured, and assembly / It is an object of the present invention to provide an optical device that can be adjusted easily.

  To achieve the above object, a first optical device according to the present invention includes a first lens holding frame in which a first lens is assembled and a second lens holding frame in which a second lens is assembled. And a base material that integrally holds the first lens holding frame and the second lens holding frame, the first lens holding frame is fitted into a fitting portion formed on the base material. Then, the first lens is positioned on the base material, the second lens holding frame is fitted into the fitting portion formed on the first lens holding frame, and the second lens becomes the first lens holding frame. The second lens is configured to be positioned on the base material via the first lens holding frame.

  The second optical device according to the present invention moves in a plane perpendicular to the optical axis of the light transmitted through the first lens and the second lens when the third lens is assembled to the first optical device. A third lens holding frame arranged in a possible manner, and third lens adjusting means for moving the third lens holding frame in a plane perpendicular to the optical axis, the third lens being the first lens With respect to the first lens and the second lens positioned with each other by fitting between the holding frame and the second lens holding frame, the third lens adjusting means is arranged so that the positioning can be adjusted in the direction orthogonal to the optical axis.

  The third lens holding frame is disposed between the first lens holding frame and the second lens holding frame, and the third lens holding frame is positioned between the first lens and the second lens positioned relative to each other. It is preferable that the lens is disposed so as to be positioned and adjustable in a direction orthogonal to the optical axis.

  It is also preferable to provide a locking structure for restricting the movement of the second lens holding frame in the in-plane direction orthogonal to the optical axis.

  According to the present invention, since the second lens holding frame is fitted and positioned on the first lens holding frame that is fitted and positioned on the base material, the first lens and the second lens are arranged. Even when the adhesive cannot be used, it is possible to provide an optical device that can ensure a desired inter-lens holding accuracy and can be easily assembled and adjusted.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As an embodiment of the optical apparatus according to the present invention, FIG. 1 shows a configuration example when the present invention is applied to an objective lens of an optical microscope. The objective lens of the first embodiment is hereinafter referred to with reference to FIG. I will be described. FIG. 1 is a cross-sectional view of the objective lens I along the optical axis LI.

  The objective lens I includes a cylindrical lens barrel A, a first lens holding frame IB1 to an eleventh lens holding frame IB11 each assembled with a first lens G1 to an eleventh lens G11, and these lens holding frames IB1 to IB1. The lens includes a holding ring C for fixing the IB 11 to the lens barrel A, and the plurality of lenses G1 to G11 are fixed to the lens barrel A by the pressing ring C via the lens holding frames IB1 to IB11 and are integrally held.

  The first lens holding frame IB1 is fitted by a fitting portion a11 formed on the inner peripheral side lower end of the lens barrel A and a fitting portion b11 formed on the outer peripheral side of the first lens holding frame IB1. The lens barrel A is positioned. That is, as shown in FIG. 2, the fitting surface a11r of the lens barrel A and the fitting surface of the lens holding frame IB1 as shown in the relationship between the fitting portion a11 of the lens barrel A and the fitting portion b11 of the first lens holding frame IB1. b11r is fitted to define the position of the first lens G1 in the plane orthogonal to the optical axis with respect to the lens barrel, and the supported surface b11f of the lens holding frame IB1 is abutted and supported by the support surface a11f of the lens barrel A. The inclination of the first lens G1 with respect to the optical axis is defined, whereby the first lens G1 is positioned with respect to the lens barrel A.

  On the other hand, the lens holding frames other than the first lens holding frame IB1, that is, the second lens holding frame IB2 to the eleventh lens holding frame IB11 are not fitted to the lens barrel A, and are fitted between the lens holding frames. The mutual positional relationship is defined by the combination. For example, the second lens holding frame IB2 is fitted between a fitting portion b12 formed on the inner peripheral side of the first lens holding frame IB1 and a fitting portion b21 formed on the outer peripheral side of the second lens holding frame IB2. Accordingly, the second lens G2 is positioned relative to the first lens G1 (and the lens barrel A).

  Similarly, the third lens holding frame IB3 is formed by fitting a fitting portion b22 on the inner peripheral side of the second lens holding frame IB2 and a fitting portion b31 on the outer peripheral side of the third lens holding frame IB3, and a fifth lens holding frame IB5. Is the fitting between the inner peripheral side fitting portion b33 of the third lens holding frame IB3 and the outer peripheral side fitting portion b51 of the fifth lens holding frame IB5, and the eighth lens holding frame IB8 is the fifth lens holding frame IB5. Positioning is performed by fitting the lens holding frames together such as fitting between the fitting portion b54 on the inner peripheral side and the fitting portion b81 on the outer peripheral side of the eighth lens holding frame IB8.

  As is clear from FIG. 1, not all the lens holding frames are sequentially stacked in a fitting relationship, but a parent-child relationship positioned in a fitting relationship between lenses positioned in the fitting relationship. A lens holding frame is provided. For example, the third lens holding frame IB3 is formed with a fitting portion b32 for fitting and supporting the fourth lens holding frame IB4 on the inner peripheral side of the fitting portion b33 for fitting and supporting the fifth lens holding frame IB5. Here, the fitting part b41 of the fourth lens holding frame IB4 is fitted here, and the fourth lens G4 is positioned between the third lens G3 and the fifth lens G5.

  Further, the fifth lens holding frame IB5 has a fitting part b52 for fitting and supporting the sixth lens holding frame IB6 and an inner side of the fitting part b54 for fitting and supporting the eighth lens holding frame IB8. A fitting portion b53 for fitting and supporting the seven lens holding frame IB7 is formed, the fitting portion b61 of the sixth lens holding frame IB6 is fitted to the fitting portion b52, and the seventh lens holding is held by the fitting portion b53. The fitting part b71 of the frame IB7 is fitted, and the sixth lens G6 and the seventh lens G7 are positioned between the fifth lens G5 and the eighth lens G8. This configuration is the same for the ninth lens G9 disposed between the eighth lens G8 and the tenth lens G10. The child lens holding frame is fixed inside the lens holding frame as a parent by an adhesive method, a pressing ring method, or a fixing screw described later (see FIG. 5).

  As described above, the parent lens holding frames IB3, IB5, and IB8 (hereinafter referred to as “parent holding frame” for convenience) are used as references, and the child lens holding frames IB4, IB6, IB7, and IB9 (similarly) The objective lens can be miniaturized with a simple configuration in which the number of stacking steps is reduced by the lens configuration in which the “child holding frame” is fitted together. In addition, when the decentering accuracy can be relaxed when viewed as a group lens rather than a single lens combination, the relative positional accuracy between the lenses in the group lens is 2 to 3 μm, for example, as in the case of a combination lens that has been joined by past bonding. However, in some cases, the relative positional accuracy between the group lenses is sufficient to be about 5 to 6 μm. In such a case, it is advantageous to employ the above-described parent-child lens configuration.

  As is clear from the above description, the parent-child lens holding frame can be appropriately provided according to the configuration of the optical device to be applied. For example, a single parent holding frame has a plurality of child holding frames. A configuration in which all the lens holding frames are stacked as a parent holding frame, a configuration in which a plurality of parent holding frames having a child holding frame are fitted and held in the parent holding frame fitted and held in the lens barrel may be used.

  In the objective lens I, the first lens holding frame IB1 to the eleventh lens holding frame IB11 are fitted together to assemble a connecting block of the lens holding frame, and then the connecting block is integrated into the lens barrel A integrally. At this time, as already described with reference to FIG. 2, the fitting portion a11 formed at the lower end on the inner peripheral side of the lens barrel A and the fitting portion formed on the outer peripheral side of the first lens holding frame IB1. By fitting with b11, the first lens holding frame IB1 is positioned in the lens barrel A, and serves as a decentration reference for the entire objective lens I. Finally, the holding ring C is screwed into the inner peripheral screw at the upper end of the lens barrel and tightened, and the connecting block of the first to eleventh lens holding frames is pressed and fixed in the direction of the optical axis LI. As a result, the first lens G1 to the eleventh lens G11 are integrally fixed and held in a state where they are positioned in the lens barrel A.

  In the objective lens I, the second lens holding frame IB2 is fitted and positioned on the first lens holding frame IB1 fitted and positioned on the lens barrel A, and thereafter the lens holding frames below the third lens holding frame are sequentially fitted and positioned. Therefore, even when the lenses cannot be bonded with an adhesive, the desired inter-lens holding accuracy can be ensured and assembly / adjustment can be easily performed.

  Next, in the objective lens I, the first to eleventh lenses G1 to G11 are position-adjusted and fixed to the lens holding frames, and then the lens holding frames IB1 to IB11 are fitted to each other by the fitting portions. Although a configuration for positioning on the machine is employed, the following describes a lens holding frame configuration means that is more effective for improving the positional accuracy of each lens. FIG. 3 is an explanatory diagram of a high-precision processing method using the second lens holding frame IB2 in the objective lens I shown in FIG. 1 as an example.

  The second lens holding frame IB2 has an outer shape that has been processed and molded within a predetermined dimensional accuracy in advance before performing this high-precision processing, and the second lens G2 is caulked or on the outer periphery of the lens (outside the optical path). It is fixed to the second lens holding frame IB2 by fixing means such as bonding. Then, it is attached to the work holding table 2 of the optical precision lathe via an employment tool (fixing jig for processing the lens holding frame) 1 manufactured corresponding to the lens holding frame.

  In the optical precision lathe, the first eccentricity detecting means 5 that detects the position of the reflected light from the R1 surface by irradiating the lens surface R1 of the second lens G2 with the detection light through the axis of the rotation axis in the precision lathe. The second eccentricity detecting means 6 for irradiating the lens surface R2 with detection light and detecting the position of the reflected light from the R2 surface, the state of touching of the reflected light detected by these eccentricity detecting means 5 and 6, and the like Is provided with an arithmetic processing unit for calculating the position and inclination of the optical axis L2 of the second lens G2.

  The optical precision lathe also includes a 6-degree-of-freedom adjustment mechanism for finely adjusting the position and inclination of the second lens holding frame IB2 with respect to the rotation axis of the precision lathe, and an adjustment mechanism based on the calculation result of the arithmetic processing unit. A control device for controlling the operation is provided, and the control device operates the adjustment mechanism based on the position and inclination (deviation from the rotation axis) of the optical axis L2 of the second lens G2 calculated by the arithmetic processing device, The optical axis L2 of the second lens G2 is aligned with the rotational axis of the precision lathe.

  In this way, in the state where the optical axis L2 of the second lens G2 coincides with the rotational axis of the precision lathe, precision cutting of the two fitting portions b21 and b22 of the second lens holding frame IB2 is performed by the cutting tool 3. . That is, the fitting surface b21r and the supported surface b21f of the fitting portion b21 fitting with the fitting portion b12 of the first lens holding frame IB1, and the fitting portion fitting with the fitting portion b31 of the third lens holding frame IB3. The fitting surface b22r and the support surface b22f in b22 are cut with high accuracy under the one chuck. Therefore, with reference to the optical axis L2 of the second lens G2, the diameters of the fitting surfaces b21r and b22r, the parallelism between the supported surface b21f and the supporting surface b22f, and the flange thickness d between these two surfaces are processed with high accuracy. be able to.

  Then, the fitting surfaces b21r and b22r with respect to the optical axis L2 of the second lens G2 serve as the lens decentering, the lens thickness is determined by the flange thickness d, and the optical axis of the lens is tilted by the supporting surface and the supported surfaces 21f and 22f. A second lens holding frame maintained with high accuracy is configured. Since the objective lens I has a structure in which the lens holding frames IB <b> 1 to IB <b> 11 processed with high accuracy in this way are stacked, an objective lens with extremely low aberration can be configured.

  Next, FIG. 4 shows a second configuration example when the present invention is applied to an objective lens of an optical microscope. The objective lens II of the second embodiment will be described below with reference to this figure. FIG. 4 is a sectional view taken along the optical axis LII of the objective lens II. The objective lens II of the present embodiment is mainly different from the objective lens I described above in the configuration of the third lens holding frame to the ninth lens holding frame, and the other components are substantially the same. The first to eleventh lenses G1 to G11, the pressing ring C, etc. are assigned the same reference numerals and redundant description is omitted. On the other hand, for each lens holding frame, in order to avoid confusion with the lens holding frames IB1 to IB11 of the first embodiment, the first, second, tenth and eleventh lens holding frames common to the first embodiment are used. Including the prefix II, it is shown as IIB1 to IIB11.

  The objective lens II includes a cylindrical lens barrel A, a first lens holding frame IIB1 to an eleventh lens holding frame IIB11 each assembled with a first lens G1 to an eleventh lens G11, and these lens holding frames IIB1 to IIB1. A plurality of lenses G1 to G11 are fixed to the lens barrel A by the pressing ring C via the lens holding frames IIB1 to IIB11 and are integrally held. The first lens holding frame IIB1 and the second lens holding frame IIB2 are the same as the first lens holding frame IB1 and the second lens holding frame IB2 described above, respectively.

  On the other hand, the fourth lens holding frame IIB4 to the ninth lens holding frame IIB9 move in a plane perpendicular to the optical axis LII of the light transmitted through the objective lens II, unlike the lens holding frames IB4 to IB9 of the above-described embodiments. A lens adjustment mechanism is provided that is arranged in a movable manner and moves the movable lens holding frame in a plane orthogonal to the optical axis LII. For example, the fourth lens holding frame IIB4 has a loose backlash in the radial direction with respect to the third lens holding frame IIB3 and is arranged to be movable in a direction orthogonal to the optical axis LII. The eccentric position can be adjusted by the provided lens adjustment mechanism.

  FIGS. 5 (1) and 2 (2) show a configuration example of a lens adjustment mechanism of a lens holding frame having a parent-child relationship, taking the third lens holding frame IIB3 and the fourth lens holding frame IIB4 as an example. That is, the fourth lens holding frame IIB4 that is the child holding frame is formed such that the outer peripheral surface b41r thereof has a predetermined adjustment margin (backlash) with respect to the inner peripheral surface b32r of the third lens holding frame IIB3. In the third lens holding frame IIB3, three or more tool holes (or screw holes) 7 extending radially in a plane orthogonal to the optical axis are formed through the collar portion.

  An adjustment tool (for example, an adjustment jig or adjustment screw using a micrometer or the like) is inserted into the tool hole 7, and the fourth lens G4 is fixed by the same eccentricity detection means as the eccentricity detection means 5 and 6 described above. Detecting the optical axis position and adjusting the eccentric position of the fourth lens G4 with respect to the third lens G3 with high precision by adjusting the fourth lens holding frame IIB4 against the third lens holding frame IIB3. Can do.

  After adjusting the eccentric position of the fourth lens G4, in the configuration example shown in FIG. 5A, the third lens holding frame IIB3 and the fourth lens holding frame IIB4 are fixed by the adhesive 8 applied to the outside of the optical path after the eccentricity adjustment. In the configuration example shown in FIG. 5 (2), the pressing ring 9 is tightened after the eccentricity adjustment, and the fourth lens holding frame IIB4 is fixed to the third lens holding frame IIB3. In FIG. 4 (and explanatory diagrams of the objective lenses III to V described below), the description of the fixing means for the child holding frame such as the fourth lens holding frame is omitted in order to avoid complication of the drawing.

  In the objective lens II having such a lens adjustment mechanism, a lens that requires an eccentric accuracy exceeding the mechanical fitting accuracy (for example, about ≦ 3 μm) between the lenses is driven by the above adjustment, and the eccentric accuracy is about 1 μm. Can be improved. The lens holding frames whose eccentric positions are highly adjusted are assembled into a connecting block by fitting the lens holding frames to each other, and the connecting block is incorporated into the lens barrel A to form the objective lens II. Therefore, it is possible to provide an objective lens that secures a desired inter-lens holding accuracy while simplifying the overall configuration of the objective lens.

  Next, FIG. 6 shows a third configuration example when the present invention is applied to an objective lens of an optical microscope. The objective lens III of the third embodiment will be described below with reference to this figure. FIG. 6 is a sectional view taken along the optical axis LIII of the objective lens III. The reference numerals shown in the figure are the same as those of the second embodiment described above, and the prefix III is assigned to each lens holding frame in order to avoid confusion with the lens holding frames of the first and second embodiments. , IIIB1 to IIIB11.

  In the objective lens III, the first lens holding frame IIIB1 to the ninth lens holding frame IIIB9 are sequentially fitted with the lens holding frames IIIB2 to IIIB9 on the basis of the first lens holding frame IIIB1 fitted and positioned on the lens barrel A. In order to reduce the “coma aberration” that is most problematic in the non-junction lens configuration, a holding frame for a predetermined lens having a large influence on the increase / decrease in coma aberration, for example, as shown in FIG. In the embodiment, the lens holding frame IIIB10 of the tenth lens G10 is provided so as to be movable in a plane perpendicular to the optical axis LIII by providing a backlash in diameter between the lens barrel A and the tenth lens holding frame. A lens adjustment mechanism that moves in a plane orthogonal to the axis LII is provided so that fine adjustment is possible.

  In the objective lens III, the outer diameter of the tenth lens holding frame IIIB10 is processed to be smaller than the outer diameters of the other lens holding frames IIIB1 to IIIB9 and IIIB11. The lens barrel A is aligned with the height position where the tenth lens holding frame IIIB10 is disposed, and screw holes (or tool holes) extending radially in a plane perpendicular to the optical axis LIII penetrate the lens barrel A. The eccentric adjusting screw (holoset) 10 for pushing and pulling the tenth lens holding frame IIIB10 is screwed into the screw hole.

  Further, the lens barrel A has three screw holes that are aligned with the height position where the ninth lens holding frame IIIB9 is disposed and extend radially in a plane perpendicular to the optical axis LIII. The locking screws 11 screwed into these screw holes are engaged with the outer peripheral surface of the ninth lens holding frame IIIB9 to fix the ninth lens holding frame IIIB9 in the radial direction. For this reason, when the eccentric adjustment is performed by pushing and pulling the tenth lens holding frame IIIB10 with the eccentricity adjusting screw 10, the ninth lens holding frame IIIB9 and the ninth lens holding frame IIIB9 are brought into surface contact with the tenth lens holding frame IIIB10. The fifth lens holding frame IIIB5 to the second lens holding frame IIIB2 sequentially fitted are prevented from moving by being dragged in a direction orthogonal to the optical axis LIII. In the objective lens III, the eleventh lens G11 which is the final lens is not normally required to have high decentering accuracy. Therefore, in the present embodiment, the eleventh lens holding frame IIIB11 is fitted to the inner wall surface of the lens barrel A. It is configured to be supported together.

  In the case of such a structure having a lens holding frame dedicated for decentration adjustment after assembling the lens, the objective lens III is measured for the coefficient component of the Zernike polynomial using transmitted wavefront aberration measuring means such as a Fizeau interferometer, and the coma aberration is determined. By looking at the values of the specified coefficient components (Z7, Z8, Z14, Z15,...), The adjustment screw 10 can be finely adjusted in the direction of decreasing each coefficient component, and the coma aberration can be driven. Also, by looking at the value of the coefficient component (Z9, Z16, Z25, Z36 ...) that defines the spherical aberration, the interval between the flange portions of the predetermined lens holding frame, for example, a shim is sandwiched or the flange portion is slightly shaved, etc. To adjust to reduce the spherical aberration. Furthermore, look at the value of the coefficient component that defines astigmatism (Z5, Z6, Z12, Z13, Z21, Z22, Z32, Z33 ...), rotate the specified lens holding frame relatively, and drive in the direction to make it smaller It is also possible.

  Next, the objective lens IV of the fourth embodiment will be described with reference to FIG. This objective lens IV is the same as the objective lens II (see FIG. 4) of the second embodiment described in the basic configuration, and the decentering of the lens can be adjusted after the objective lens is assembled. Although it is the same as that of the objective lens III (see FIG. 6), it is configured to be able to adjust the eccentricity of the child holding frame in the eighth lens holding frame IVB8 and the ninth lens holding frame IVB9 that are in a parent-child relationship.

  That is, in the objective lens IV, the ninth lens holding frame IVB9 that is a child holding frame is formed with a predetermined adjustment margin in the radial direction with respect to the eighth lens holding frame IVB8. Three or more screw holes extending radially in the plane orthogonal to the optical axis are formed, and an adjustment screw 12 for pushing and pulling the ninth lens holding frame IVB9 in the direction orthogonal to the optical axis is screwed together. A tool hole 14 for inserting a tool for adjusting the adjusting screw 12 is formed in the lens barrel A so as to match the height position of the adjusting screw 12, and the number 9 of the adjusting screw 12 is formed from the outer periphery of the lens barrel A. The eccentric position of the lens G9 can be adjusted. The tool hole 14 formed in the lens barrel A can be formed as follows. A large number of holes are made in the lens barrel A, and at least some of the holes are assembled so as to match the screw holes into which the adjusting screws 12 are screwed. Alternatively, a long hole is formed along the outer periphery of the lens barrel A so that the tool can access the screw hole into which the adjustment screw 12 is screwed from any position of the long hole.

  The ninth lens holding frame IVB9 is incorporated in advance into the eighth lens holding frame IVB8, the center position of the ninth lens holding frame IVB8 is adjusted by the adjusting screw 12, and the ninth lens holding frame IVB9 is pressed by the pressing ring 13 to form a parent-child lens holding frame. Then, it is assembled into a connection block together with other lens holding frames IVB1 to IVB7, IVB9, and IVB10, and is assembled into the lens barrel A by the pressing ring C to form the objective lens IV.

  In the objective lens IV configured as described above, the assembled objective lens IV is measured using a transmitted wavefront aberration measuring means such as a Fizeau interferometer, and coefficient components (Z7, Z8, Z14, Z15,...) Of the obtained Zernike polynomial are obtained. ), The adjustment screw 12 can be finely adjusted in the direction of decreasing each coefficient component, and the coma aberration can be driven.

  In the objective lens IV, the upper and lower lenses G8 and G10 sandwiching the decentered ninth lens G9 are positioned relative to each other by fitting the eighth lens holding frame IVB8 and the tenth lens holding frame IVB10. The ninth lens G9 can be adjusted in the eccentric position between the eighth lens and the tenth lens in which the mutual positional relationship is positioned as described above. Therefore, according to such a configuration, the intermediate lens (G9) is secured while ensuring high relative position accuracy for the upper and lower lenses (G8, G10) by using the processing means using the optical precision lathe described above. By configuring so that fine adjustment is possible, it is possible to configure an objective lens in which coma aberration and the like that are difficult to define only by the fitting position accuracy are reduced.

  Next, the objective lens V of the fifth embodiment will be described with reference to FIG. The objective lens V has the same basic configuration as the objective lens I of the first embodiment described above (see FIG. 1), and adjusts the eccentricity of the ninth lens holding frame VB9 which is a child holding frame after the objective lens is assembled. This is similar to the objective lens IV of the fourth embodiment (see FIG. 7).

  That is, in the objective lens V, the ninth lens holding frame VB9 is formed with a predetermined adjustment margin in the radial direction with respect to the eighth lens holding frame VB8, and the eighth lens holding frame VB8 is in the plane orthogonal to the optical axis. At least three screw holes extending radially are formed, and adjustment screws 12 for pushing and pulling the ninth lens holding frame VB9 in the direction perpendicular to the optical axis are screwed together. A tool hole 14 for inserting a tool for adjusting the adjusting screw 12 is formed in the lens barrel A so as to match the height position of the adjusting screw 12, and the number 9 of the adjusting screw 12 is formed from the outer periphery of the lens barrel A. The eccentric position of the lens G9 can be adjusted.

  The ninth lens holding frame VB9 is incorporated in advance in the eighth lens holding frame VB8, the center position of the ninth lens holding frame VB9 is adjusted by the adjusting screw 12, and the ninth lens holding frame VB9 is pressed by the pressing ring 13 to form a parent-child lens holding frame. Further, the lens holding frames VB1 to VB7, VB9, and VB10 are fitted and connected to each other to be assembled into a connecting block, and are assembled into the lens barrel A by the pressing ring C to form the objective lens V.

  In the objective lens V configured as described above, the assembled objective lens V is measured using a transmitted wavefront aberration measuring means such as a Fizeau interferometer, and coefficient components (Z7, Z8, Z14, Z15,...) Of the obtained Zernike polynomial are obtained. ), The adjustment screw 12 can be finely adjusted in the direction of decreasing each coefficient component, and the coma aberration can be driven.

  Similarly to the objective lens IV described above, the objective lens V adjusts the eccentricity between the upper and lower lenses G8 and G10 positioned with each other by fitting the eighth lens holding frame VB8 and the tenth lens holding frame VB10. A possible ninth lens holding frame VB9 is provided, and the eccentric position can be adjusted between the eighth lens G8 and the tenth lens G10 in which the ninth lens G9 is positioned relative to each other. Further, in the objective lens V, the parent holding frames (VB1, VB2, VB3, VB5, VB8, VB10, and VB11) are mechanically fitted from the first lens holding frame VB1 to the final 11th lens holding frame VB11. Are configured to be positioned relative to each other.

  According to such a configuration, a large number of lenses incorporated in the objective lens V by using the processing means using the optical precision lathe described above can be positioned in the middle while ensuring high relative position accuracy with a simple configuration. The desired lens (the ninth lens G9 in the present embodiment) can be finely adjusted, and an objective lens with reduced coma and the like that is difficult to define only with the fitting position accuracy can be configured. it can.

  Therefore, according to the present invention described above, it is possible to configure the apparatus with high accuracy and low aberration even in an optical apparatus that uses ultraviolet rays that cannot be bonded to each other with an adhesive as an observation wavelength. In addition, since a complicated adjustment mechanism for each lens is not built in the apparatus main body except for the final aberration adjustment mechanism for correcting aberrations, a small optical device can be provided with a simple and easy configuration.

  In each of the embodiments described above, a configuration example in which the first lens holding frame is fitted to the lens barrel has been shown. However, any of the first to nth lens holding frames can be fitted to the lens barrel as a lens holding frame. Also good. For example, the fifth lens holding frame located in the middle is used as a lens holding frame (first lens holding frame in the claims) that fits into the lens barrel (base material), and is positioned by fitting up and down across this. A lens holding frame (second lens holding frame in claims) may be provided. Similarly, although the configuration example in which the fourth to tenth lens holding frames are adjustable in the direction perpendicular to the optical axis is shown, any of the second to nth lens holding frames may be used as an adjustable lens holding frame.

   In addition, the configuration includes a cylindrical barrel that has a mount screw and a body-mounted surface for attaching the objective lens to the microscope body and surrounds the entire lens holding frame, but each lens holding frame is fitted or mutually connected. It is a structure that can be assembled to the base material as a position-adjusted connection block. By providing a structure that integrates the connection block (for example, a structure that presses and fixes the lens holding frame in the optical axis direction), the lens barrel is eliminated, It is also possible to configure the material in a flange shape.

  Further, in the embodiment, the example in which the present invention is applied to the objective lens of the optical microscope has been described. However, the present invention is not limited to such an embodiment, and a plurality of lenses and a lens holding frame for holding each lens are provided. If it is an optical apparatus having the same, it can be similarly applied to other apparatuses such as a semiconductor device manufacturing apparatus, an inspection apparatus, and an imaging apparatus, and the same effects can be obtained.

It is sectional drawing of the objective lens of 1st Example at the time of applying this invention to an optical microscope. It is explanatory drawing which shows the relationship between the fitting part of a lens-barrel and the fitting part of a 1st lens holding frame in the said objective lens. It is explanatory drawing for demonstrating the processing method of a lens holding frame. It is sectional drawing of the objective lens of 2nd Example. In the objective lens of 2nd Example, it is sectional drawing which showed the structural example of the adjustment mechanism of a lens holding frame, (1) is the structural example which adheres and fixes a lens holding frame after position adjustment, (2) is after position adjustment. It is an example of a structure which fixes a lens holding frame with a pressing ring. It is sectional drawing of the objective lens of 3rd Example. It is sectional drawing of the objective lens of 4th Example. It is sectional drawing of the objective lens of 5th Example.

Explanation of symbols

A Lens tube (base material)
a11 Lens tube side fitting part (fitting part formed on the base material)
B1 to B11 First to eleventh lens holding frames (prefix symbols I to V indicate the first to fifth embodiments)
b11 Outer peripheral side fitting portion of the first lens holding frame b12 Inner peripheral side fitting portion of the first lens holding frame (fitting portion formed on the first lens holding frame)
G1 to G11 1st to 11th lenses I to V Objective lens (optical device)
LI to LV Optical axis 10, 12 Adjustment screw (third lens adjustment means)
11 Locking screw (locking structure)

Claims (4)

A first lens holding frame to which the first lens is assembled;
A second lens holding frame assembled with a second lens;
In an optical device comprising: a base material that integrally holds the first lens holding frame and the second lens holding frame;
The first lens holding frame is fitted to a fitting portion formed on the base material, and the first lens is positioned on the base material,
The second lens holding frame is fitted into a fitting portion formed on the first lens holding frame, and the second lens is positioned on the first lens holding frame;
Accordingly, the optical device is configured such that the second lens is positioned on the base material via the first lens holding frame. A third lens holding frame that is assembled with a third lens and is movably disposed in a plane perpendicular to the optical axis of light transmitted through the first lens and the second lens;
Third lens adjusting means for moving the third lens holding frame in a plane orthogonal to the optical axis;
The third lens is adjusted by the third lens adjusting means with respect to the first lens and the second lens, which are positioned relative to each other by fitting the first lens holding frame and the second lens holding frame. The optical apparatus according to claim 1, wherein the optical apparatus is disposed so as to be positioned and adjustable in a direction orthogonal to the optical axis.   The third lens holding frame is disposed between the first lens holding frame and the second lens holding frame, and between the first lens and the second lens positioned relative to each other. The optical device according to claim 3, wherein the third lens is disposed so as to be positioned and adjustable in a direction orthogonal to the optical axis.   4. The locking structure for restricting movement of the second lens holding frame in an in-plane direction orthogonal to the optical axis is provided on the base material. 5. An optical device according to 1.

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