JP2008026568A - Optical microscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a polarization prism and tubular member disposed in a slider unit to be easily switchably arranged on the optical axis of an objective lens. <P>SOLUTION: The optical microscope 100 includes the slider unit 16 in which a holding mechanism 301 and an electric drive mechanism 302 are disposed in a slider body 30. The holding mechanism 301 integrally holds: a Nomarski prism 14 that converges or diverges two polarization light rays caused to interfere with each other for differential interference observation; and a light-shield tubular component 15 by which a dark-field illumination optical path OP1 coaxial with the optical axis OA of an objective lens 7 is separated from an observation optical path OP2. The power drive mechanism 302 moves the holding mechanism 301 in the direction of a drive shaft MA perpendicular to the optical axis OA and thus electrically switches the Nomarski prism 14 or light-shield tubular component 15 to the position that is on the optical axis OA. In addition, when the Nomrski prism 14 is disposed on the optical axis OA, the electric drive mechanism 302 electrically moves the Nomarski prism 14 in the direction of the drive shaft MA minutely. The slider unit 16 is inserted into or removed from a revolver device 19 in the vicinity of the pupil of the objective lens 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical microscope capable of performing sample observation by switching at least differential interference observation and dark field observation.

  Conventionally, for example, a sample having a minute unevenness formed on the surface, such as a circuit pattern formed on a semiconductor wafer, and having a substantially uniform reflectivity over the entire surface, the light interference is used to observe the sample. 2. Description of the Related Art An optical microscope capable of performing differential interference observation that forms an observation image by converting a phase difference of light corresponding to various irregularities into a contrast between light and dark is used.

  Usually, such an optical microscope is configured so that sample observation can be performed by switching to bright field observation or dark field observation, which are more general observation methods. In this case, differential interference observation is realized by adding a polarizer, an analyzer, and a polarizing prism as optical elements that generate and interfere with two orthogonal polarized lights to an optical system that performs bright field observation or dark field observation. . As this polarizing prism, a Nomarski prism is generally used, and is disposed on the optical axis in the vicinity of the pupil of the objective lens.

  In differential interference observation, in order to perform retardation adjustment that adjusts the phase difference between two polarized light beams that interfere with each other, the position of the polarizing prism placed on the optical axis of the objective lens is finely adjusted in a direction perpendicular to the optical axis. There is a need to. For this reason, differential interference observation has a problem that it takes time and effort for observation compared to bright field observation and the like. On the other hand, an optical microscope that electrically inserts and removes a polarizing prism and adjusts retardation has been developed (see, for example, Patent Document 1).

  The optical microscope described in Patent Document 1 includes a slider unit in which a Nomarski prism and an actuator are integrally provided, so that labor and time can be saved by electrically operating the Nomarski prism insertion / removal arrangement and retardation adjustment. ing. This slider unit can be inserted into and removed from the microscope main body, and can be used universally between a plurality of optical microscopes.

Japanese Patent Laid-Open No. 9-325281 Japanese Patent Laid-Open No. 11-326777

  However, in the optical microscope described in Patent Document 1, the following problems may occur when switching from differential interference observation to dark field observation. That is, in the optical microscope described in Patent Document 1, when the Nomarski prism is removed from the optical path of the objective lens and dark field observation is performed, a dark field coaxial with the optical axis of the objective lens is located at the insertion / removal position of the Nomarski prism. There is no partition or the like separating the illumination optical path from the observation optical path. For this reason, a part of the dark field illumination light is reflected by the peripheral object and enters the observation optical path, which may cause stray light. In order to solve this problem, for example, it is necessary to additionally arrange a cylindrical member as a partition in the space from which the Nomarski prism is removed.

  In differential interference observation, in order to obtain an image with an appropriate contrast, it is necessary to exchange and use Nomarski prisms having different shearing amounts, which are two polarization shift amounts, according to the objective lens. Furthermore, when observation is performed using an objective lens having a different pupil position, it is necessary to change the arrangement position of the Nomarski prism in the optical axis direction according to the pupil position. However, the optical microscope described in Patent Document 1 does not take into account such exchange and change of arrangement.

  On the other hand, there is an optical microscope described in Patent Document 2. This optical microscope includes a cylindrical member and a plurality of Nomarski prisms having different shearing amounts in a revolver device that holds an objective lens, and each of them can be switched and arranged on the optical axis electrically. Accordingly, it is possible to cope with prevention of stray light when switching to dark field observation, switching to a Nomarski prism having a different shearing amount, and change of the arrangement position of the Nomarski prism.

  However, in the optical microscope described in Patent Document 2, the revolver device becomes large and complicated, is difficult to attach to and detach from the microscope main body, can be used only for a specific optical microscope, and has a problem that versatility is impaired. there were. Further, it is necessary to provide a plurality of Nomarski prisms in advance, and there is a problem that the apparatus cost increases.

  The present invention has been made in view of the above, and easily switches and arranges a polarizing prism and a cylindrical member on the optical axis of an objective lens while maintaining versatility and low cost with a small and simple configuration. An optical microscope equipped with a slider unit that can change the polarizing prism to a polarizing prism having a different shearing amount, etc., and can change the arrangement of the polarizing prism according to the pupil position of the objective lens. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, an optical microscope according to claim 1 is an optical microscope capable of performing specimen observation by switching at least differential interference observation and dark field observation. A holding mechanism that integrally holds a polarizing prism that splits and splits the two polarized light beams that interfere with each other, and a cylindrical member that separates the dark field illumination optical path coaxial with the optical axis of the objective lens and the observation optical path; An electric drive mechanism that moves the holding mechanism in a direction orthogonal to the lens optical axis and electrically switches and arranges the polarizing prism or the cylindrical member on the lens optical axis; And the slider unit is inserted into and removed from the microscope main body in the vicinity of the pupil of the objective lens.

  Further, in the optical microscope according to claim 2, in the above invention, the electric drive mechanism electrically drives the polarizing prism in a direction orthogonal to the lens optical axis when the polarizing prism is disposed on the lens optical axis. It is characterized by fine movement.

  The optical microscope according to a third aspect of the present invention is characterized in that, in the above invention, the holding mechanism holds the polarizing prism interchangeably.

  The optical microscope according to claim 4 is characterized in that, in the above invention, the holding mechanism is capable of changing a holding interval between the polarizing prism and the cylindrical member in the orthogonal direction.

  Further, in the optical microscope according to claim 5, in the above invention, the holding mechanism may be configured such that the deflection prism is more than the holding interval when the cylindrical member is disposed on the lens optical axis. The holding interval when arranged on the lens optical axis is shortened.

  An optical microscope according to a sixth aspect of the present invention is the above invention, wherein, in the above-described invention, the electric drive mechanism switches the deflecting prism and the cylindrical member, and the polarizing prism is disposed on the lens optical axis. And a control means for performing fine control of the deflecting prism in the orthogonal direction.

  According to the optical microscope of the present invention, a slider unit is realized while maintaining versatility and low cost with a small and simple configuration, and the polarizing prism and the cylindrical member disposed in the slider unit are connected to the objective lens. The switching prism can be easily switched on the optical axis, the polarizing prism can be replaced with a polarizing prism having a different shearing amount, and the arrangement of the polarizing prism can be changed according to the pupil position of the objective lens.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of an optical microscope according to the invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment. In the description of the drawings, the same parts are denoted by the same reference numerals.

(Embodiment 1)
First, an optical microscope according to the first embodiment of the present invention will be described. FIG. 1 is a diagram illustrating a main configuration of the optical microscope 100 according to the first embodiment. The optical microscope 100 can perform sample observation by switching at least between differential interference observation and dark field observation, and FIG. 1 shows a configuration particularly in the case of performing differential interference observation.

  As shown in this figure, an optical microscope 100 includes an illumination optical system 10 configured using a light source 1, an illumination lens 2, an aperture stop 3, a field stop 4, an illumination lens 5, an observation cube 6 and an objective lens 7, An observation optical system 11 configured to serve as both the objective lens 7 and the observation cube 6 is provided. The polarizer 12 and the analyzer 13 necessary for differential interference observation are detachably disposed in the illumination optical system 10 and the observation optical system 11 in the vicinity of the observation cube 6, respectively. In addition, the Nomarski prism 14 as a polarizing prism that combines and splits two polarized light beams that interfere with each other in the differential interference observation is disposed in the vicinity of the pupil of the objective lens 7 so as to be detachable on the optical axis OA.

  Illumination light emitted from the light source 1 using a lamp such as a halogen lamp is imaged by the illumination lenses 2 and 5 to form a conjugate image of the light source 1 on the pupil of the objective lens 7. Thereafter, the specimen 8 is irradiated with the illumination light by the objective lens 7. Meanwhile, the aperture stop 3 and the field stop 4 define the numerical aperture and illumination area of the illumination light for the specimen 8, respectively. The polarizer 12 extracts linearly polarized light in a predetermined vibration direction from the illumination light, and the observation cube 6 reflects the linearly polarized light toward the Nomarski prism 14. The Nomarski prism 14 splits the incident linearly polarized light into two linearly polarized lights having vibration directions orthogonal to each other, and emits the two branched linearly polarized lights in different directions. The objective lens 7 irradiates the sample 8 telecentrically with the two linearly polarized lights.

  The two irradiated linearly polarized lights are reflected as observation light by the specimen 8 and enter the Nomarski prism 14 through the objective lens 7. The Nomarski prism 14 combines these two linearly polarized lights coaxially and emits them in parallel with the optical axis OA. The two synthesized linearly polarized light passes through the observation cube 6 and enters the analyzer 13. The analyzer 13 extracts linearly polarized light having a common vibration direction from each of the two synthesized linearly polarized lights. The extracted observation light forms an observation image of the specimen 8 through an imaging optical system (not shown). The formed observation image is picked up by an image pickup device and observed on the image, or visually observed through an eyepiece lens or the like.

  Further, the optical microscope 100 includes a light shielding cylindrical part 15 as a cylindrical member disposed on the optical axis OA in place of the Nomarski prism 14 when switching from differential interference observation to dark field observation. The Nomarski prism 14 and the light shielding cylindrical part 15 are arranged in a slider unit 16 configured using an integral housing. The optical microscope 100 places the slider unit 16 in the vicinity of the pupil of the objective lens 7. It is provided so that it can be inserted into and removed from the microscope body. The slider unit 16 is provided with an electric drive mechanism for switching and arranging the Nomarski prism 14 and the light-shielding cylindrical part 15, and the optical microscope 100 includes a control unit 17 that controls the operation of the electric drive mechanism. ing. The control unit 17 is connected to an input unit 18 for inputting various instruction information, and controls the electric drive mechanism based on the instruction information acquired from the input unit 18. Details of the electric drive mechanism will be described later. The control unit 17 and the input unit 18 are realized using a personal computer, a hand controller, a hand switch, or the like.

  FIGS. 2A and 2B are diagrams illustrating a configuration of the revolver device 19 in which the objective lens 7 is inserted and removed, and shows a state where the slider unit 16 is inserted into the revolver device 19. FIG. 2A is a plan view, and FIG. 2B is a side view. Since the Nomarski prism 14 needs to be arranged in the vicinity of the pupil of the objective lens 7, the optical microscope 100 is provided with a slider insertion / removal hole 19a in a revolver device 19 corresponding to a part of the microscope main body. The Nomarski prism 14, that is, the slider unit 16 is inserted into the hole 19a.

  The slider unit 16 is inserted until it comes into contact with the contact surface 19b at the back of the slider insertion / removal hole 19a, and is fixed by the fixing knob 19c while being in contact with the contact surface 19b. Thus, the slider unit 16 is disposed and fixed at a predetermined position with respect to the revolver device 19, that is, the objective lens 7. After the slider unit 16 is fixed, the arrangement of the Nomarski prism 14 and the light shielding cylindrical part 15 can be switched without moving the slider unit 16 relative to the revolver device 19. Details thereof will be described later.

  On the other hand, FIGS. 3A and 3B are views showing a state in which the slider unit 16 is inserted into the revolver device 19 and the Nomarski prism 14 in the slider unit 16 is retracted from the optical axis OA. Here, FIG. 3A shows a state in which nothing is arranged in the space 20 on the optical axis OA where the Nomarski prism 14 is retracted as a state according to the prior art, and FIG. 3-2 shows the state on the optical axis OA. The state which has arrange | positioned the light shielding cylinder component 15 in the space 20 is shown.

  When performing dark field observation with the Nomarski prism 14 retracted, in the state shown in FIG. 3A, a portion of the dark field illumination light 21 that passes through the annular dark field illumination optical path OP1 along the optical axis OA. May be reflected by objects around the optical path and enter the observation optical path OP2 as stray light 22, for example. On the other hand, in the state shown in FIG. 3B, since the light shielding cylinder part 15 separates the dark field illumination optical path OP1 and the observation optical path OP2, the stray light 22 does not enter the observation optical path OP2. As described above, when switching from differential interference observation to dark field observation, the optical microscope 100 can prevent stray light from being generated and obtain a clear specimen image by arranging the light shielding cylindrical part 15 in place of the Nomarski prism 14. it can.

  When switching to an observation method other than differential interference observation, dark field observation, and bright field observation, the slider unit 16 can be removed from the slider insertion / removal hole 19a as necessary. In addition, when the slider unit 16 is inserted into the slider insertion / removal hole 19a, the slider unit 16 is described as being positioned at the treatment position by contacting the contact surface 19b. However, a dedicated positioning mechanism may be provided separately.

  Note that a conventional optical microscope capable of performing differential interference observation is generally equipped with an insertion / removal hole for inserting / removing a Nomarski prism. The optical microscope 100 according to the first embodiment can use such a general insertion / removal hole as the slider insertion / removal hole 19a. In other words, the slider unit 16 has a general insertion / removal hole. By being inserted into the hole, it can be used for a conventional optical microscope.

  Next, the configuration of the slider unit 16 will be described in detail. 4A and 4B are diagrams illustrating an external configuration of the slider unit 16. FIG. 4-1 is a plan view, and FIG. 4-2 is a side view. The Nomarski prism 14 provided in the slider unit 16, the light shielding cylindrical part 15, and the electric drive mechanism for switching the arrangement thereof are disposed in a slider main body 30 as a casing. The slider body 30 is covered with a cover 32, and the cover 32 is attached to the slider body 30 with four screws 31. In this state, the electric drive mechanism in the slider main body 30 and the control unit 17 (see FIG. 1) provided outside are electrically connected by the cable 33.

  The cover 32 is provided with openings Au1 and Au2 through which dark field illumination light and observation light pass when performing dark field observation. The aperture Au2 allows bright field illumination light and observation light to pass during bright field observation. Similarly, openings Ad1 and Ad2 are provided on the bottom surface of the slider body 30 at positions facing the openings Au1 and Au2 (see FIG. 5A).

  FIG. 5A is a plan view showing the slider unit 16 with the cover 32 removed. As shown in this figure, the internal structure of the slider unit 16 includes a holding mechanism 301 that holds the Nomarski prism 14 and the light-shielding cylindrical part 15, and an electric drive mechanism 302 that moves the holding mechanism 301 along the drive shaft MA. Broadly divided. FIG. 5B is a side sectional view mainly showing the holding mechanism 301, and FIG. 5C is a side sectional view mainly showing the electric drive mechanism 302. FIG. 5-4 is a partial cross-sectional view showing a portion not shown in FIGS. 5-2 and 5-3.

  A linear motion guide 34 is fixed to the slider body 30 with screws 35, and a prism fixing component 36 is fixed on the linear motion guide 34 with screws 37. Thereby, the prism fixing component 36 is provided so as to be movable in the direction of the drive axis MA orthogonal to the optical axis OA. In the linear motion guide 34, driving errors such as pitching and yawing during driving are sufficiently suppressed, and linearity is ensured with high accuracy.

  The Nomarski prism 14 is bonded and fixed to the prism fixing part 36, and the light shielding cylinder part 15 is fixed with screws 39. Thus, the Nomarski prism 14 and the light shielding cylinder part 15 are integrally held by the prism fixing part 36. The holding interval between the Nomarski prism 14 and the light shielding cylinder part 15 is set to a predetermined distance D1. This holding interval corresponds to the inter-axis distance between the central axis OB of the Nomarski prism 14 and the central axis OC of the cylindrical portion 15a in the light shielding cylindrical component 15.

  The electric drive mechanism 302 includes a stepping motor 40. The stepping motor 40 is fixed to the motor mounting part 41 with screws 42, and the motor mounting part 41 is fixed to the slider body 30 with screws 43. The motor shaft 40 a of the stepping motor 40 is coupled to the feed screw 44 through the coupling 45 using screws 46 and 47. Further, a support component 50 including two bearings 48 and 49 is fixed to the slider body 30 with screws 51, and the shaft portion 44 a of the feed screw 44 is supported by the bearings 48 and 49.

  Here, the central axes of the motor shaft 40a, the coupling 45, the bearings 48 and 49, and the shaft portion 44a are provided at the same height with respect to the slider body 30, and the displacement in the direction perpendicular to the central axis is not limited. The inclination is kept small enough. For this reason, the stepping motor 40 can smoothly transmit the driving force to the feed screw 44 and can rotate the feed screw 44. The feed screw 44 is provided with a step portion 44 b so that the feed screw 44 itself does not move in a direction approaching the stepping motor 40. Further, a retaining member 44c is provided at the tip of the feed screw 44 so that the feed screw 44 is not pulled out.

  The male screw portion 44 d of the feed screw 44 meshes with a female screw portion 36 a provided in the prism fixing component 36, whereby the rotational power of the stepping motor 40 is converted into direct acting power and transmitted to the prism fixing component 36. A tension spring 54 is engaged with the spring hooking part 52 fixed to the prism fixing part 36 and the spring hooking part 53 fixed to the slider body 30. As a result, the prism fixing part 36 is always biased toward the spring hooking part 53, so that backlash between the male screw part 44d and the female screw part 36a does not occur. Here, the biasing force by the tension spring 54 is suppressed to such an extent that the torque of the stepping motor 40 is not affected.

  On the other hand, a sensor plate 55 is fixed to one end of the prism fixing part 36 with a screw 56. On the other hand, an origin sensor 57 such as a photo interrupter is fixed to the slider body 30 with screws 58. The origin sensor 57 is disposed at a position where the sensor plate 55 can be detected when the center axis OC of the light shielding cylindrical part 15 and the optical axis OA coincide with each other. Thereby, the origin sensor 57 detects the rotation position of the stepping motor 40 when the sensor plate 55 is detected as the reference position. The internal cable 59 connected to the stepping motor 40 and the internal cable 60 connected to the origin sensor 57 are introduced into the cable 33 and grouped together. The cable 33 is connected to the control unit 17, and power is also supplied through the cable 33. The cable 33 is fixed to the slider body 30 by a cable fixing component 61 and a screw 62.

  The control unit 17 sends various control signals to the stepping motor 40 via the cable 33 and the internal cable 59. Accordingly, the control unit 17 performs control for driving the stepping motor 40. In addition, the stepping motor 40 is driven to rotate by a predetermined amount, and control is performed so that the Nomarski prism 14 and the light shielding cylindrical part 15 are switched and arranged on the optical axis OA. Further, when the Nomarski prism 14 is arranged on the optical axis OA, the control unit 17 causes the stepping motor 40 to perform a minute amount of rotational drive for retardation adjustment, and finely moves the Nomarski prism 14 in the direction of the drive axis MA. Take control.

  Here, the control unit 17 determines the control content for the stepping motor 40 based on the instruction information from the input unit 18. In addition, the control unit 17 acquires the detection result from the origin sensor 57 via the internal cable 60 and the cable 33 and confirms the reference position of the stepping motor 40.

  Next, an operation performed by the electric drive mechanism 302 based on the control by the control unit 17 will be described. First, as an initial operation, when the power is turned on by the control unit 17, the stepping motor 40 rotates and drives the sensor plate 55 to the reference position detected by the origin sensor 57. As a result, as shown in FIG. 5A, a state in which the light shielding cylindrical part 15 is arranged on the optical axis OA, that is, a state (initial state) in which the central axis OC of the light shielding cylindrical part 15 is aligned with the optical axis OA ,Stop.

  Next, when instruction information for switching to differential interference observation is input from the input unit 18 and a control signal for placing the Nomarski prism 14 on the optical axis OA is input from the control unit 17, the stepping motor 40 A predetermined amount of rotational drive is performed from the reference position. This rotational power is transmitted from the coupling 45 to the feed screw 44. As a result, the prism fixing component 36 is moved from the initial state along the drive axis MA by a distance D1 equal to the holding interval between the Nomarski prism 14 and the light shielding cylinder component 15, and the Nomarski prism 14 is moved as shown in FIG. Arranged on the optical axis OA. At this time, the central axis OB of the Nomarski prism 14 coincides with the optical axis OA. The stepping motor 40 rotates to the reference position in the opposite direction to the above-described driving when the Nomarski prism 14 is retracted from the optical axis OA.

  Next, in the state where the Nomarski prism 14 is disposed on the optical axis OA, instruction information for performing retardation adjustment is input from the input unit 18, and a control signal for finely moving the Nomarski prism 14 in the direction of the drive axis MA is received. When input from the control unit 17, the stepping motor 40 performs a minute amount of rotational driving. At this time, the stepping motor 40 finely moves the Nomarski prism 14 within a predetermined distance D2, as shown in FIGS. 7-1 and 7-2, based on the state shown in FIG. In other words, the stepping motor 40 moves the center axis OB once aligned with the optical axis OA by a minute distance within the range of the distance D2 in either direction of the drive axis MA. The moving distance and moving direction are instructed by the control unit 17 based on the instruction information input from the input unit 18.

  Here, in the initial operation, the stepping motor 40 has been described as being temporarily stopped after being rotationally driven to the reference position. However, the stepping motor 40 is not necessarily stopped. For example, if differential interference observation has been performed immediately before the power of the electric drive mechanism 302 is turned off last time, the control unit 17 arranges the Nomarski prism 14 on the optical axis OA following the initial operation, and performs retardation adjustment. It is also possible to drive the stepping motor 40 as is done. In this case, the control unit 17 stores the position of the Nomarski prism 14 in the previous differential interference observation, that is, the rotational drive position of the stepping motor 40, etc. in a storage unit (not shown).

  Further, for example, the control unit 17 stores the optimum retardation amount for each of the plurality of objective lenses 7 arranged to face the specimen 8, that is, the rotational driving position of the stepping motor 40 in the storage unit, and based on the stored information. The Nomarski prism 14 can also be automatically arranged in conjunction with the replacement of the objective lens 7. The arrangement control of the Nomarski prism 14 by the control unit 17 is not limited to the above, and various methods and procedures can be realized.

  As described above, in the optical microscope 100 according to the first embodiment, at least the differential interference observation and the dark field observation can be switched to perform the sample observation, and the two polarized light beams interfered by the differential interference observation can be combined. And a Nomarski prism 14 as a polarizing prism, and a light shielding cylindrical part 15 as a cylindrical member that separates the dark field illumination optical path OP1 and the observation optical path OP2 coaxial with the optical axis OA of the objective lens 7 are integrally held. The holding mechanism 301 and the holding mechanism 301 are moved in the direction of the drive axis MA orthogonal to the optical axis OA, and the Nomarski prism 14 or the light-shielding cylindrical part 15 is electrically switched on the optical axis OA. Is arranged on the optical axis OA, the electric drive mechanism 30 that electrically finely moves the Nomarski prism 14 in the direction of the drive axis MA. When, with the slider unit 16 is disposed in the slider body 30 and the slider unit 16 is inserted into and removed from the revolver unit 19 forming part of the microscope body at near the pupil of the objective lens 7.

  For this reason, in the optical microscope 100, the Nomarski prism 14 and the light shielding cylindrical part 15 can be easily switched and arranged on the optical axis OA of the objective lens 7. In the optical microscope 100, since the holding mechanism 301 and the electric drive mechanism 302 can be realized without using a particularly complicated mechanism, the slider unit 16 can be mounted while maintaining versatility and low cost with a small and simple configuration. Can be realized.

(Embodiment 2)
Next, an optical microscope according to the second embodiment of the present invention will be described. In the first embodiment described above, the slider unit 16 includes the specific Nomarski prism 14, but in the second embodiment, the Nomarski prism 14 can be replaced with a Nomarski prism having a different shearing amount and the like. The arrangement position of the Nomarski prism can be changed according to the objective lens having a different pupil position.

  8A to 8C are diagrams illustrating an external configuration of the slider unit 116 included in the optical microscope according to the second embodiment. 8-1 is a plan view, FIG. 8-2 is a side view, and FIG. 8-3 is a bottom view. As shown in these drawings, the slider unit 116 includes a slider main body 130 instead of the slider main body 30 based on the configuration of the slider unit 16, and is detachably attached to the bottom surface of the slider main body 130 with screws 71. The access panel 70 is provided. As a result, the slider unit 116 can easily access a holding mechanism, which will be described later, disposed in the slider body 130 by simply removing the access panel 70. The optical microscope according to the second embodiment has the same configuration as the optical microscope 100 except that the slider unit 116 is provided instead of the slider unit 16.

  9A and 9B are diagrams illustrating the internal configuration of the slider unit 116. FIG. FIG. 9A is a plan view illustrating a state where the cover 32 is removed. As shown in this figure, the internal configuration of the slider unit 116 includes a holding mechanism 303 instead of the holding mechanism 301 based on the internal configuration of the slider unit 16. That is, it is roughly configured using the holding mechanism 303 and the electric drive mechanism 302. FIG. 9-2 is a side sectional view mainly showing the holding mechanism 303. As shown in these drawings, the holding mechanism 303 includes a prism holding part 72 and a prism fixing part 73 instead of the prism fixing part 36 based on the configuration of the holding mechanism 301. The light shielding cylinder part 15 is fixed to the prism fixing part 73 with screws 39.

  FIGS. 10A and 10B are diagrams illustrating a partial configuration of a peripheral portion of the Nomarski prism 14 and the light shielding cylindrical part 15 in the holding mechanism 303. FIGS. 10-1 is a side view, and FIG. 10-2 is a bottom view. As shown in these drawings, the Nomarski prism 14 is bonded and fixed to a prism holding part 72, and the prism holding part 72 is detachably attached to the prism fixing part 73 by screws 74. Since the prism holding component 72 and the prism fixing component 73 are in contact with the mounting surfaces 72a and 73a, a predetermined positional relationship is always reproduced even when the attachment and detachment is repeated.

  In the holding mechanism 303, the shearing amount and the like can be appropriately changed by attaching / detaching the prism holding component 72 to / from the prism fixing component 73 and replacing the Nomarski prism 14 with another Nomarski prism. Further, by replacing the prism holding component 72 with another prism holding component, the holding position of the Nomarski prism, that is, the arrangement position on the optical axis OA can be appropriately changed.

  Here, an example of the replacement procedure will be described. First, the slider unit 116 is extracted from the slider insertion / removal hole 19a, and the access panel 70 is removed from the slider body 130 as shown in FIG. Next, as shown in FIG. 12A, the prism holding component 72 is removed from the prism fixing component 73 together with the Nomarski prism 14. Then, at least one of the Nomarski prism 14 or the prism holding part 72 is replaced with a corresponding other part and attached to the prism fixing part 73. Thereafter, the access panel 70 is attached to the slider main body 130, and the slider unit 116 is inserted into the slider insertion / removal hole 19a.

  FIGS. 12-2 and 12-3 are diagrams illustrating examples of replacement parts of the Nomarski prism 14. These drawings show a case where a Nomarski prism 14 ′ having a different shearing amount is attached to the prism holding component 72 instead of the Nomarski prism 14. As a result, the slider unit 116 can exhibit a larger amount of shearing. 12-2 is a plan view, and FIG. 12-3 is a side sectional view.

  On the other hand, FIGS. 12-4 and 12-5 are diagrams illustrating an example of a replacement part of the prism holding part 72. FIG. In these drawings, instead of the prism holding component 72, a prism holding component 72 ′ having a thicker outer shape and a different height for holding the Nomarski prism 14 is used, and the Nomarski prism 14 is attached thereto. ing. Thereby, the slider unit 116 can appropriately arrange the Nomarski prism 14 with respect to the objective lens having a pupil position higher than that of the objective lens 7. 12-4 is a plan view, and FIG. 12-5 is a partially cutaway side view.

  As described above, the holding mechanism 303 provided in the slider unit 116 according to the second embodiment is configured such that the Nomarski prism 14 as the polarizing prism and the prism holding component 72 that is the holding component are attached to the prism fixing component 73. Easily replaceable. For this reason, the optical microscope according to the second embodiment can be used by appropriately replacing the Nomarski prism having different shearing amounts and the like, and the Nomarski prism can be appropriately arranged according to the pupil position of the objective lens. it can. Further, these replacements and arrangement changes can be easily performed.

  Thereby, the optical microscope according to the second embodiment can be more functionally used for differential interference observation. The slider unit 116 can also be applied to a conventional optical microscope capable of differential interference observation more functionally and versatilely. In the slider unit 116, the access panel 70 is provided so that the parts can be replaced only by partially opening the slider unit 116, so that the amount of dust and the like entering the inside during the replacement work is reduced. can do.

(Embodiment 3)
Next, an optical microscope according to the third embodiment of the present invention will be described. In the first and second embodiments described above, the holding interval between the Nomarski prism 14 and the light shielding cylindrical part 15 is fixed to a predetermined distance D1, but in the third embodiment, the holding interval can be changed. Yes.

  FIG. 13A is a diagram illustrating an internal configuration of the slider unit 216 included in the optical microscope according to the third embodiment. As shown in this figure, the slider unit 216 includes a holding mechanism 304 instead of the holding mechanism 301 based on the configuration of the slider unit 16. That is, the slider unit 216 includes the holding mechanism 304 and the electric drive mechanism 302 roughly inside the slider body 30. FIG. 13-2 shows a part of the holding mechanism 304 as a side view. The optical microscope according to the third embodiment has the same configuration as the optical microscope 100 except that the slider unit 216 is provided instead of the slider unit 16.

  As shown in FIGS. 13A and 13B, the holding mechanism 304 is based on the configuration of the holding mechanism 301, replacing the light shielding cylinder part 15, the screw 39, and the prism fixing part 36 with the light shielding cylinder part 80, A restriction pin 81 and a prism fixing part 82 are provided, and a spring hooking part 83 and a compression spring 84 are further provided. The light shielding cylindrical part 80 is provided with two elongated holes 80a parallel to the drive shaft MA, and four restricting pins 81 are attached to the prism fixing part 82 through the elongated holes 80a.

  Further, the end 80b of the light shielding cylinder part 80 is bent and provided with a hole 80c. A spring hooking component 83 is attached to the end of the prism fixing component 82 facing the end 80b through the hole 80c. Further, the compression spring 84 is sandwiched between the retaining portion 83 a at the tip of the spring hook component 83 and the end portion 80 b of the light shielding cylinder component 80 in a state where the shaft portion 83 b of the spring hook component 83 is inserted. .

  The holding interval between the Nomarski prism 14 and the light shielding cylinder part 80, that is, the inter-axis distance between the central axis OB of the Nomarski prism 14 and the central axis OC ′ of the cylindrical portion 80 d in the light shielding cylinder part 80 is determined by the biasing force of the compression spring 84. When the end 80b of the light shielding cylindrical part 80 is pressed against the prism fixing part 82, the predetermined distance D1 is obtained as in the first and second embodiments. The urging force of the compression spring 84 is set to a magnitude that does not affect the driving force of the stepping motor 40.

  Further, the light shielding cylinder part 80 is restricted from moving in the vertical direction (optical axis OA direction) with respect to the prism fixing part 82 by the flange part 81a of the restriction pin 81, while the elongated hole part 80a and the four restriction pins 81 The hole 80c and the spring hooking part 83 are provided so as to be movable in the direction of the drive shaft MA.

  Next, operations of the electric drive mechanism 302 and the holding mechanism 304 when the Nomarski prism 14 is arranged on the optical axis OA will be described. First, as an initial operation, when the power is turned on by the control unit 17, the stepping motor 40 is rotationally driven to the reference position to be in the initial state shown in FIG.

  Next, when instruction information for switching to differential interference observation is input from the input unit 18 and a control signal for placing the Nomarski prism 14 on the optical axis OA is input from the control unit 17, the stepping motor 40 A predetermined amount of rotational drive is performed from the reference position. This rotational power is transmitted from the coupling 45 to the feed screw 44. As a result, the prism fixing part 82, that is, the Nomarski prism 14 is moved from the initial state along the drive axis MA by a distance D1 equal to the holding interval.

  At this time, before the prism fixing component 82 finishes moving the distance D1, the cylindrical portion 80d of the light shielding cylindrical component 80 is brought into contact with the inner wall portion 30a of the slider main body 30 as shown in FIG. Assuming that the movement amount of the prism fixing component 82 remains at this point by the distance D3, the holding interval between the Nomarski prism 14 and the light-shielding cylinder component 80, that is, the center is maintained by continuing the movement of the prism fixing component 82 thereafter. The inter-axis distance between the axis OB and the central axis OC ′ is a distance D4 that is shorter than the distance D1 by a distance D3, as shown in FIG. 14-2.

  In this state, the end 80b of the light shielding cylindrical part 80 is separated from the end of the opposing prism fixing part 82 by the distance D3, and the compression spring 84 is compressed by the distance D3 by the end 80b. Further, the position of the long hole portion 80a of the light shielding cylinder part 80 with respect to the regulation pin 81 is shifted by the distance D3 in the direction of the drive axis MA. In contrast, the cylindrical portion 80d does not change its position after being in contact with the inner wall portion 30a.

  On the other hand, when the Nomarski prism 14 is retracted from the optical axis OA, the stepping motor 40 rotates to the reference position in the opposite direction to the above-described driving. At that time, until the Nomarski prism 14, that is, the prism fixing part 82 is moved by the distance D3, the cylindrical portion 80d is kept in contact with the inner wall portion 30a by the urging force of the compression spring 84, while the central axis OB and the central axis OC ′. Is extended to a distance D1 according to the movement distance (see FIG. 14-1). Thereafter, the distance between the axes is maintained at the distance D1, and the cylindrical portion 80d moves together with the prism fixing component 82 and is rearranged on the optical axis OA (see FIG. 13-1).

  Next, in the state where the Nomarski prism 14 is disposed on the optical axis OA, instruction information for performing retardation adjustment is input from the input unit 18, and a control signal for finely moving the Nomarski prism 14 in the direction of the drive axis MA is received. When input from the control unit 17, the stepping motor 40 performs a minute amount of rotational driving. At this time, the stepping motor 40 finely moves the Nomarski prism 14 within a predetermined distance D2, as shown in FIGS. 15-1 and 15-2, based on the state shown in FIG. 14-2. In other words, the stepping motor 40 moves the center axis OB once aligned with the optical axis OA by a minute distance within the range of the distance D2 in either direction of the drive axis MA. The moving distance and moving direction are instructed by the control unit 17 based on the instruction information input from the input unit 18.

  At that time, the cylindrical portion 80d of the light shielding cylindrical component 80 is kept in contact with the inner wall portion 30a and does not change its position. On the other hand, the inter-axis distance between the central axis OB and the central axis OC 'varies within the range of distances (D4-D2) to (D4 + D2). Here, FIGS. 15A and 15B are shown assuming that the distance D2 is equal to the distance D3. The distances D2 and D3 are substantially equal to the widths of the substantially ring-shaped openings Ad1 and Au1 through which dark field illumination light passes. As a result, the distance D1 is set to be approximately equal to the minimum distance mechanically possible.

  As described above, the holding mechanism 304 provided in the slider unit 216 according to the third embodiment has a holding interval between the Nomarski prism 14 as a polarizing prism and the cylindrical portion 80d of the light shielding cylindrical component 80 as a cylindrical member. It can be changed in the direction of the drive axis MA, and in particular, the holding interval when the Nomarski prism 14 is arranged on the optical axis OA is shortened compared to the holding interval when the cylindrical portion 80d is arranged on the optical axis OA. Like to do. For this reason, in the optical microscope according to the third embodiment, the slider unit 216 can be further miniaturized and provided, and space saving of the microscope body configuration can be promoted. Further, the slider unit 216 can be applied more generally to a conventional optical microscope capable of differential interference observation.

  Although the third embodiment has been described as including a mechanism using the compression spring 84 in order to change the holding interval between the Nomarski prism 14 and the cylindrical portion 80d of the light-shielding cylindrical component 80, such a mechanism is described. It is not limited. For example, the cylindrical portion 80d may be configured using an elastic material such as rubber. In this case, the cylindrical portion 80d is deformed so that the cylindrical shape is crushed in the direction of the drive shaft MA when the cylindrical portion 80d is further pressed by the prism fixing component 82 after being in contact with the inner wall portion 30a. The holding interval can be shortened. Further, when the Nomarski prism 14 is retracted, it can be used repeatedly by making its shape recoverable. In addition, for example, when the prism fixing part 82 is pushed in, the retreat space required in the drive axis MA direction is reduced by retreating the cylindrical portion 80d not only in the drive axis MA direction but also in a direction orthogonal thereto. can do.

  Up to this point, the best mode for carrying out the present invention has been described as the first to third embodiments. However, the present invention is not limited to the above-described first to third embodiments, and may be within the scope of the present invention. Various modifications are possible.

  For example, in Embodiments 1 to 3 described above, the electric drive mechanism 302 includes the linear motion guide 34 as a mechanism for linearly moving the prism fixing parts 36, 73, 82, but is limited to the linear motion guide. Instead of this, other guide mechanisms can be used. Further, although one stepping motor 40 is provided as a drive source for moving the prism fixing parts 36, 73, 82, the invention is not limited to the stepping motor, and other actuators may be used. Further, the number of actuators is not limited to one, and a plurality of actuators may be used. For example, a coarse motion actuator for switching and arranging a Nomarski prism and a light shielding cylinder part, and a fine motion actuator for performing retardation adjustment may be provided. .

It is a figure which shows the structure of the optical microscope concerning Embodiment 1 of this invention. It is a figure which shows the structure of the revolver apparatus with which the optical microscope shown in FIG. 1 is equipped, and a slider unit. It is a figure which shows the structure of the revolver apparatus with which the optical microscope shown in FIG. 1 is equipped, and a slider unit. It is a figure explaining the effect | action of a light shielding cylinder component. It is a figure explaining the effect | action of a light shielding cylinder component. FIG. 2 is a diagram illustrating an external configuration of a slider unit according to the first embodiment. FIG. 2 is a diagram illustrating an external configuration of a slider unit according to the first embodiment. FIG. 3 is a diagram illustrating an internal configuration of a slider unit according to the first embodiment. FIG. 3 is a diagram illustrating an internal configuration of a slider unit according to the first embodiment. FIG. 3 is a diagram illustrating an internal configuration of a slider unit according to the first embodiment. FIG. 3 is a diagram illustrating an internal configuration of a slider unit according to the first embodiment. It is a figure explaining the arrangement | positioning switching operation | movement of the Nomarski prism and light shielding cylinder component concerning Embodiment 1. FIG. FIG. 6 is a diagram illustrating a retardation adjustment operation according to the first embodiment. FIG. 6 is a diagram illustrating a retardation adjustment operation according to the first embodiment. FIG. 6 is a diagram illustrating an external configuration of a slider unit according to a second embodiment. FIG. 6 is a diagram illustrating an external configuration of a slider unit according to a second embodiment. FIG. 6 is a diagram illustrating an external configuration of a slider unit according to a second embodiment. FIG. 6 is a diagram illustrating an internal configuration of a slider unit according to a second embodiment. FIG. 6 is a diagram illustrating an internal configuration of a slider unit according to a second embodiment. It is a figure which shows the partial structure of the holding mechanism with which the slider unit concerning Embodiment 2 is provided. It is a figure which shows the partial structure of the holding mechanism with which the slider unit concerning Embodiment 2 is provided. It is a figure which shows the slider unit of the state which removed the access panel shown to FIGS. 8-3. It is a figure which shows the state which isolate | separated the prism holding component and the prism fixing component. It is a figure which shows an example of the replacement part of a Nomarski prism. It is a figure which shows an example of the replacement part of a Nomarski prism. It is a figure which shows an example of replacement parts of a prism holding component. It is a figure which shows an example of replacement parts of a prism holding component. FIG. 6 is a diagram illustrating an internal configuration of a slider unit according to a third embodiment. It is a figure which shows the partial structure of the holding mechanism with which the slider unit concerning Embodiment 3 is provided. It is a figure explaining the arrangement | positioning switching operation | movement of the Nomarski prism and light shielding cylinder component concerning Embodiment 3. FIG. It is a figure explaining the arrangement | positioning switching operation | movement of the Nomarski prism and light shielding cylinder component concerning Embodiment 3. FIG. FIG. 10 is a diagram for explaining a retardation adjusting operation according to the third embodiment. FIG. 10 is a diagram illustrating a retardation adjustment operation according to the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2, 5 Illumination lens 3 Aperture stop 4 Field stop 6 Observation cube 7 Objective lens 8 Specimen 10 Illumination optical system 11 Observation optical system 12 Polarizer 13 Analyzer 14 Nomarski prism 15 Light-shielding cylinder part 15a Tube part 16, 116, 216 Slider unit DESCRIPTION OF SYMBOLS 17 Control part 18 Input part 19 Revolver apparatus 19a Slider insertion / removal hole 19b Contact surface 19c Fixed knob 20 Space 21 Dark field illumination light 22 Stray light 30,130 Slider main body 30a Inner wall part 31,35,37,39,42,43, 46, 47, 51, 56, 58, 62, 71, 74 Screw 32 Cover 33 Cable 34 Linear motion guide 36 Prism fixing part 40 Stepping motor 41 Motor mounting part 44 Feed screw 45 Coupling 48, 49 Bearing 50 Supporting part 52, 5 Spring hooking part 54 Tension spring 55 Sensor plate 57 Origin sensor 59, 60 Internal cable 61 Cable fixing part 70 Access panel 72 Prism holding part 73 Prism fixing part 80 Light-shielding cylinder part 80a Long hole part 80b End part 80c Hole 80d Tube part 81 Restriction Pin 82 Prism fixing part 83 Spring hanging part 84 Compression spring 100 Optical microscope 301, 303, 304 Holding mechanism 302 Electric drive mechanism MA Drive axis OA Optical axis OB, OC, OC 'Central axis OP1 Dark field illumination optical path OP2 Observation optical path

Claims (6)

In an optical microscope that can perform specimen observation by switching at least differential interference observation and dark field observation,
A polarizing prism that combines and splits two polarized light beams that interfere with the differential interference observation and a cylindrical member that isolates the dark field illumination optical path coaxial with the lens optical axis of the objective lens and the observation optical path are integrally held. A holding mechanism;
An electric drive mechanism that moves the holding mechanism in a direction orthogonal to the lens optical axis and electrically switches and arranges the polarizing prism or the cylindrical member on the lens optical axis;
Equipped with a slider unit disposed in the housing,
The optical microscope, wherein the slider unit is inserted into and removed from a microscope main body in the vicinity of the pupil of the objective lens.   2. The optical microscope according to claim 1, wherein when the polarizing prism is arranged on the lens optical axis, the electric driving mechanism electrically moves the polarizing prism in a direction orthogonal to the lens optical axis.   The optical microscope according to claim 1, wherein the holding mechanism holds the polarizing prism interchangeably.   The optical microscope according to claim 1, wherein the holding mechanism can change a holding interval between the polarizing prism and the cylindrical member in the orthogonal direction.   The holding mechanism shortens the holding interval when the deflection prism is arranged on the lens optical axis as compared to the holding interval when the cylindrical member is arranged on the lens optical axis. The optical microscope according to claim 4.   Control means for performing control to finely move the deflecting prism in the orthogonal direction when the electric driving mechanism switches the deflecting prism and the cylindrical member and arranges the polarizing prism on the lens optical axis. The optical microscope according to claim 1, wherein the optical microscope is provided.

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