Optical apparatus for performing observations and measurements by using images of measured objects

An optical apparatus including: a stage on which an object is mounted; an observation section including an imaging system forming an image of the object; a shaft rotatable in a first direction and a second direction opposite to the first direction; a drive that moves the observation section or the stage in a third direction defying a gravity according to rotation of the shaft in the first direction and in a fourth direction opposite to the third direction according to rotation of the shaft in the second direction; and a torque controller including a clutch that permits rotation of the shaft in the first direction, inhibits rotation of the shaft in the second direction, and rotates in the second direction with the shaft as a rotation force in the second direction is input to the shaft, and a restriction section restricting rotation of the clutch.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Priority Patent Application JP 2014-230627 filed Nov. 13, 2014, the entire contents of which are incorporated herein by reference.

BACKGROUND

The present disclosure relates to an optical apparatus that performs observations and measurements based on work images.

From the past, optical apparatuses that form images of works by optical systems each including an objective lens and an imaging lens and perform observations and measurements based on the work images have been known. For example, in a measurement projection apparatus, an image of a work is projected by a projection section, and the projected work is visually measured. Also in an image measurement apparatus, an image of a work is projected by a digital camera or the like, and a measurement or the like is performed based on the digital image. In the optical apparatuses as described above, it is important to highly-accurately focus on a work image.

The focusing is performed by relatively moving a stage on which a work is mounted and a measurement head on which an imaging optical system is mounted in a vertical direction, for example. Typically, one of the stage and the measurement head is moved upwardly or downwardly by rotating a rotation handle. By the weight of the stage or the measurement head, a difference may be caused between a rotation torque requisite for the raising and a rotation torque requisite for the lowering. An increase in the difference between the rotation torques requisite for the upward and downward movements induces lowering of operability of the optical apparatus.

Japanese Patent Application Laid-open No. Hei 06-6159 (hereinafter, referred to as Patent Document 1) discloses, though in a totally different field, a brake unit obtained by combining a friction-type brake and a one-way clutch. By using the brake unit, it is possible to equalize the rotation torques requisite for lowering and raising a lifter plate on which an automobile or the like is mounted (see, for example, left column of page 3 in Patent Document 1).

SUMMARY

Also in the optical apparatus, a technique that suppresses a difference between torques requisite for raising and lowering a stage or a measurement head and enables focusing to be performed with high operability is desired.

In view of the circumstances as described above, there is a need for an optical apparatus capable of performing focusing with high operability.

According to an embodiment of the present disclosure, there is provided an optical apparatus including a mounting section, an observation section, a shaft section, a drive section, and a torque control section.

On the mounting section, an object is mounted.

The observation section includes an imaging optical system that forms an image of the object mounted on the mounting section.

The shaft section is rotatable in a first direction and a second direction opposite to the first direction.

The drive section moves one of the observation section and the mounting section in a third direction that defies a gravity according to a rotation of the shaft section in the first direction and in a fourth direction opposite to the third direction according to a rotation of the shaft section in the second direction.

The torque control section includes a clutch section that permits the rotation of the shaft section in the first direction, inhibits the rotation of the shaft section in the second direction, and rotates in the second direction with the shaft section as a rotation force in the second direction is input to the shaft section, and a restriction section that restricts the rotation of the clutch section.

In the optical apparatus, the rotation of the shaft section in the first direction is permitted by the clutch section. Therefore, it is possible to move the observation section or the mounting section in the third direction defying the gravity without increasing requisite torques. On the other hand, when a rotation force in the second direction is input to the shaft section, both of the shaft section and the clutch section rotate, and the rotation of the clutch section is restricted by the restriction section. Accordingly, a torque that acts on the shaft section due to the weight of the observation section or the mounting section can be controlled. As a result, focusing can be performed with high operability.

The clutch section may include a one-way clutch provided in the shaft section and a plate-like section that is formed in a circumferential section of the one-way clutch and rotates with the shaft section in the second direction. In this case, the restriction section may include one or more pressing members that are pressed against the plate-like section to restrict the rotation of the plate-like section.

With this structure, torque control can be performed with a simple structure.

The plate-like section may include at least one surface that is pressed by the one or more pressing members.

With this structure, the rotation of the plate-like section can be restricted sufficiently.

The plate-like section may include a first surface and a second surface that oppose each other in an extension direction of the shaft section. In this case, the restriction section may include a first pressing member that presses the first surface of the plate-like section and a second pressing member that presses the second surface of the plate-like section.

By sandwiching the plate-like section by the first pressing member and the second pressing member, the rotation of the plate-like section can be restricted for sure.

The restriction section may include a first supporting surface that supports the first pressing member toward the first surface and a second supporting surface that is provided while a distance thereof from the first supporting surface is changeable in the extension direction of the shaft section and supports the second pressing member toward the second surface.

By changing the distance between the first and second supporting surfaces, forces with which the first and second pressing members press the plate-like section can be changed. Therefore, torque control can be executed highly accurately.

The restriction section may include a first supporting section including the first supporting surface, a second supporting section including the second supporting surface, whose position with respect to the first supporting section is changeable in the extension direction of the shaft section, and a fixing section that fixes the position of the second supporting section with respect to the first supporting section.

By separately providing the first supporting section including the first supporting surface and the second supporting section including the second supporting surface, the distance between the first and second supporting surfaces can be changed with ease.

The fixing section may include a fixing hole formed on the first supporting section, a through hole formed on the second supporting section, and a fixing member that penetrates the through hole to be inserted into the fixing hole.

Since the fixing member penetrates the through hole formed in the second supporting section to be inserted into the fixing hole of the first supporting section, the position of the second supporting section can sufficiently be prevented from fluctuating.

The plate-like section may be formed annularly about the shaft section. In this case, the first pressing member and the second pressing member may each include one or more washer members.

By using the washer, the torque control section can be realized with a simple structure.

The one or more washer members may include a wave washer.

By using the wave washer, a pressing force with respect to the plate-like section can be controlled. As a result, highly-accurate torque control becomes possible.

As described above, according to the embodiment of the present disclosure, focusing can be performed with high operability. It should be noted that the described effects are not necessarily limited and may be any of the effects described in the disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1are diagrams each schematically showing an outer appearance of a projection apparatus as an optical apparatus according to an embodiment of the present disclosure.FIG. 1Ais a front view of the projection apparatus100(in y direction), andFIG. 1Bis a side view of the projection apparatus100(in x direction).

The projection apparatus100includes a base section10, an observation section20, a stage (mounting section)40, and an illumination section45. The base section10is a part to be mounted on a desk or the like and has a practically cuboid shape in this embodiment.

In an area substantially ¾ the area from a front side (left-hand side inFIG. 1B) to a rear side (right-hand side inFIG. 1B) of an upper surface11of the base section10, the stage40on which a work (object) W is mounted is provided. The stage40is connected to an x-axis movement mechanism and a y-axis movement mechanism (both of which are not shown). As the movement mechanisms are operated by a user or driven automatically, the stage40becomes movable in the x and y directions. Specific structures of the movement mechanisms are not limited.

The observation section20includes a head section21and a supporting column section22. As shown inFIG. 1, the supporting column section22is provided on the rear side of the upper surface11of the base section10at a position next to the stage40. The supporting column section22has a substantially cuboid shape and extends in a z direction.

The head section21is coupled to an upper surface section of the supporting column section22. The head section21includes an imaging optical system25that forms an image of the work W mounted on the stage40and a projection optical system26that projects the formed image of the work W.

As shown inFIG. 1, the imaging optical system25includes an objective lens28provided on a lower surface27of the head section21at a position opposing the stage40. The imaging optical system25also includes various optical members (not shown) such as an imaging lens, that are provided in the head section21. The structure of the imaging optical system25is not limited, and an arbitrary structure may be adopted. Typically, an imaging optical system capable of forming an image while enlarging the image of the work W is used, and the formed enlarged image is projected by the projection optical system.

The projection optical system26includes a display section30provided on a front surface29of the head section21. The display section30is circular, and an enlarged image of the work W is projected onto the display section30, for example. The user visually checks the projected image of the work W to perform a shape inspection and the like.

The projection optical system26also includes various optical members (not shown) such as a reflective mirror provided in the head section21. The structure of the projection optical system26is not limited, and an arbitrary structure may be adopted. For example, a structure in which a part of the imaging optical system25also functions as the projection optical system26may be adopted.

The illumination section45includes a transparent illumination section46and a reflective illumination section47. The transparent illumination section46is provided inside the base section10at a position below the stage40. Light emitted from the transparent illumination section46is irradiated onto the work W via emission ports (not shown) formed on the upper surface11of the base section10and the stage40. The light that has been transmitted through the work W enters the objective lens28so that the image of the work W is projected onto the display section30.

The reflective illumination section47is provided on an upper side of a front surface23of the supporting column section22. Light emitted from the reflective illumination section47is irradiated onto the work W from an oblique direction. The light reflected by the work W enters the objective lens28so that the image of the work W is projected onto the display section30.

Light may be irradiated from the reflective illumination section47toward the objective lens28and reflected by the reflective mirror and the like toward the work W. Accordingly, light can be irradiated vertically from above the work W so that the image of the work W that is based on the reflected light can be observed.

As the transparent illumination section46and the reflective illumination section47, an LED light source, a lamp, and the like are used.

As shown inFIG. 1, on a rear side of a side surface31of the base section10, a handle51that a user is capable of operating and a shaft section52coupled to the handle51are provided. When the user turns the handle51rightwardly (arrow R inFIG. 1B), the shaft section52also turns rightwardly. When the user turns the handle51leftwardly (arrow L inFIG. 1B), the shaft section52also turns leftwardly. The handle51is also an input section for inputting a rotation force to the shaft section52.

FIG. 2is a diagram for explaining upward and downward movements of the observation section20. In this embodiment, the head section21and the supporting column section22integrally move in the vertical direction along the z direction according to a user operation to the handle51(input of rotation force to shaft section52). As shown inFIG. 2, the supporting column section22has a double structure, and an inner-side supporting column section32is fixed to the base section10. The outer-side supporting column section22moves in the vertical direction along the inner-side supporting column section32.

In this embodiment, the observation section20moves upwardly according to the rightward rotation (arrow R) of the handle51and the shaft section52. Further, the observation section20moves downwardly according to the leftward rotation (arrow L) of the handle51and the shaft section52. The rightward and leftward rotations respectively correspond to a first direction and a second direction opposite to the first direction in this embodiment. Further, the upward direction in which the observation section20moves correspond to a third direction that defies a gravity, and the downward direction correspond to a fourth direction opposite to the third direction.

Hereinafter, the elevating mechanism for upwardly and downwardly moving the observation section20will be described in detail. By moving the observation section20by the elevating mechanism, a focal point of the imaging optical system25including the objective lens28can be adjusted. As a result, the focal point can be set on the image of the work W. Therefore, the elevating mechanism can also be referred to as focusing mechanism. It should be noted that in the descriptions below, with the inner-side supporting column section32being a guide section32, those two are denoted by the same reference numeral.

FIG. 3are schematic diagrams showing structural examples of the elevating mechanism of this embodiment. InFIG. 3, the illustration of the stage40is omitted. Further, the base section10shown inFIG. 3schematically shows a cross section of an area where the shaft section52is provided (position on rear side of base section10). In actuality, a supporting structure that rotatably supports the shaft section52and the like, for example, is structured inside the base section10.

The elevating mechanism50includes the handle51, the shaft section52, a torque control section53, a worm wheel gear54, a ball screw mechanism55, and a linear guide56. The worm wheel gear54rotates about the z direction according to the rotation of the shaft section52. The ball screw mechanism55includes a screw shaft57connected to the worm wheel gear54and a ball screw nut58attached to the screw shaft57. The screw shaft57extends in the z direction, and the ball screw nut58moves in the vertical direction according to the rotation of the screw shaft57.

As shown inFIG. 3, the screw shaft57extends upwardly from a bottom surface33of the guide section32. The ball screw nut58is connected to the supporting column section22of the observation section20, and the supporting column section22moves along with the movement of the ball screw nut58. The structure for connecting the ball screw nut58and the supporting column section22is not limited.

It should be noted that by appropriately setting a reduction ratio of the worm wheel gear54, a lead of the ball screw mechanism55, and the like, a feed amount of the observation section20with respect to a rotation amount of the handle51can be determined. In addition, the worm wheel gear54and the ball screw mechanism55function as a drive section in this embodiment.

The linear guide56includes guide rails59provided inside the guide section32and sliders60movably attached to the guide rails59. The guide rails59extend in the z direction from the bottom surface33of the guide section32. The sliders60are connected to the supporting column section22of the observation section20and are movable with the supporting column section22. By providing the linear guide56, raising and lowering of the observation section20can be stabilized.

In this embodiment, two guide rails59are provided, and two sliders60are respectively attached to the guide rails59. However, the structure is not limited thereto, and an arbitrary number of guide rails59and sliders60may be used. The structure that enables the sliders60and the supporting column section22to move integrally is also not limited, and an arbitrary structure may be adopted.

When the user rotates the handle51and a rightward rotation force is input to the shaft section52, the screw shaft57connected to the worm wheel gear54rotates, and the ball screw nut58moves upwardly. Accordingly, the supporting column section22moves upwardly, and the entire observation section20moves upwardly (FIG. 3AtoFIG. 3B). When a leftward rotation force is input to the shaft section52, the ball screw nut58moves downwardly, and the entire observation section20moves downwardly (FIG. 3BtoFIG. 3A).

The torque control section53permits the rightward rotation of the shaft section52and restricts the leftward rotation of the shaft section52. Therefore, the rightward rotation force input to the shaft section52is transmitted to the ball screw mechanism55without being restricted. As a result, the observation section20can be moved upwardly with a small torque without increasing requisite torques.

On the other hand, by restricting the leftward rotation of the shaft section52, it becomes possible to control a leftward torque that acts on the shaft section52due to the weight of the observation section20. In other words, a torque acts on the screw shaft57in a direction in which the ball screw nut58is lowered due to the weight of the observation section20. The torque acts on the shaft section52as the leftward torque via the worm wheel gear54. The torque control section53of this embodiment is capable of restricting the leftward torque.

Consequently, it becomes possible to suppress a difference between torques requisite for raising and lowering the observation section20and perform focusing with high operability. Moreover, it also becomes possible to exert a certain amount of drive weight and subtle stop performance in lowering the observation section20and thus perform highly-accurate focusing. In addition, it becomes possible to prevent the observation section20from gradually lowering due to the weight of the observation section20and the observation section20from lowering more than the movement amount intended by the user to eventually complicate the focusing. As a result, the operability of the projection apparatus100can be improved.

FIG. 4is a schematic diagram showing a structural example of the torque control section53. The torque control section53includes a clutch section65and a restriction section66. The clutch section65permits the rightward rotation of the shaft section52. The clutch section65inhibits the leftward rotation of the shaft section52and when a leftward rotation force is input to the shaft section52, rotates leftwardly with the shaft section52. The torque control is performed by restricting the rotation of the clutch section65by the restriction section66.

As shown inFIG. 4, the clutch section65includes a one-way clutch67provided in the shaft section52and a friction section69connected to a circumferential section68of the one-way clutch67. The shaft section52is inserted into the one-way clutch67so that only the rightward rotation of the shaft section52is permitted. The specific structure of the one-way clutch67is not limited, and a roller-type one-way clutch or the like is used, for example.

The friction section69is integrated with the one-way clutch67, and when the one-way clutch67rotates, the friction section69also rotates with the one-way clutch67. The friction section69includes a cylindrical section70extending in the same direction as the shaft section52and plate-like sections71extending vertically toward the outside from the cylindrical section70. The plate-like sections71each have a flange shape when seen from the cylindrical section70and extend perpendicular to the shaft section52.

It should be noted that it is also possible for the one-way clutch67and the friction section69to be formed separately and connected using an adhesive or the like or connected by being fitted to each other. Various other structures may also be adopted as the structure in which the plate-like sections71are provided in the circumferential section68of the one-way clutch67.

As shown inFIG. 4, the plate-like sections71are formed at substantially the center of the cylindrical section70in the x direction and each include a first surface73and a second surface74that are vertical to the x direction. The first and second surfaces73and74have ring shapes that are substantially the same when seen in the x direction.

By pressing one or more pressing members against the plate-like sections71, the restriction section66restricts the rotation of the plate-like sections71. Accordingly, the leftward rotation of the clutch section65is restricted. As shown inFIG. 4, the restriction section66includes a first supporting section75, a second supporting section76, first washer sections77as first pressing members, and second washer sections78as second pressing members.

The first supporting section75is cylindrical, and the shaft section52is inserted into an inner circumferential side thereof. The first supporting section75includes a first supporting surface79opposing the first surface73of the plate-like section71of the clutch section65. The shape of the first supporting surface79in the x direction is a ring shape that is substantially the same as that of the first surface73.

The first supporting surface79supports the first washer section77interposed between the first supporting surface79and the first surface73toward the first surface73. With this structure, the first washer section77is pressed against the first surface73, and the rotation of the plate-like section71is restricted.

The second supporting section76is also cylindrical, and the shaft section52is inserted into an inner circumferential side thereof. The second supporting section76includes a second supporting surface80opposing the second surface74of the plate-like section71. By the second supporting surface80, the second washer section78is supported toward the second surface74. With this structure, the second washer section78is pressed against the second surface74to restrict the rotation of the plate-like section71. By sandwiching the plate-like section71by the first and second washer sections77and78, the rotation of the plate-like section71can be restricted for sure. In addition, by adjusting pressing forces that act on the surfaces, subtle torque adjustments become possible.

The first and second washer sections77and78each include a wave washer81and two resin washers82sandwiching the wave washer81. By using the wave washer81, a surface pressure can be caused in each of the first and second surfaces73and74. As a result, by a friction resistance between each of the first and second surfaces73and74and the resin washers82, the rotation of the plate-like section71can be restricted for sure. Moreover, by appropriately selecting a different type of wave washer (e.g., having different wave height etc.), the pressing force with respect to the plate-like section71can be controlled.

It should be noted that as the resin washers82, a washer formed of an arbitrary resin material such as a fluorine resin may be used. Also by changing the material of the resin washers82, the pressing force with respect to the plate-like section71can be controlled. The material of the wave washer81is also not limited, and a washer formed of stainless steel, for example, may be used. Alternatively, a spring washer may be used as the pressing member.

For example, by adjusting local pressing at a part where the wave washer81comes into contact with the resin washers82, a deformation of the resin washers82can be suppressed, and uniform pressing with respect to the plate-like section71can be realized. The effects on the deformation of the resin washers82and uniform pressing can be enhanced by increasing the thickness or number of resin washers82. By suppressing the deformation of the resin washers82and enabling uniform pressing to be performed, a local abrasion of the resin washers82can be suppressed, and durability of the members can be raised.

By using the one-way clutch, the washer members, and the like, the torque control section53can be realized with a simple structure. In this case, the torque control section53can also be called one-way clutch section.

Also in this embodiment, a distance t between the first supporting surface79and the second supporting surface80is changeable. Specifically, in this embodiment, the position of the second supporting section76with respect to the first supporting section75is changeable in the x direction, and by changing the position of the second supporting section76, the distance t between the first supporting surface79and the second supporting surface80can be changed.

Although illustrations are omitted, by cutting the screw on the outer circumferential surface of the first supporting section75and the inner circumferential surface of the second supporting section76to cause the second supporting section76to rotate, the second supporting section76becomes movable in the z direction. Instead of such a structure, a groove section and convex section that movably fit with each other may be formed so that the first and second supporting sections75and76can move relatively.

When the distance t between the first and second supporting surfaces79and80becomes small, a pressing force of the first and second washer sections77and78with respect to the plate-like section71becomes large, and a force with which the rotation of the plate-like section71is restricted can be increased. On the other hand, when the distance t increases, the pressing force of the first and second washer sections77and78with respect to the plate-like section71becomes smaller, and a force with which the rotation of the plate-like section71is restricted can be decreased. By changing the distance t between the first and second supporting surfaces79and80as described above, the pressing force that acts on the plate-like section71can be changed. As a result, torque control can be executed highly accurately.

When the distance t between the first and second supporting surfaces79and80is determined, the position of the second supporting section76with respect to the first supporting section75is fixed by a fixing section85. The fixing section85includes a fixing hole86formed on the first supporting section75, a through hole87formed on the second supporting section76, and a bolt (fixing member)88that penetrates the through hole87to be inserted into the fixing hole86.

For example, one fixing hole86is formed at a predetermined position of the first supporting section75. In contrast, a plurality of through holes87are formed on an outer circumference of the second supporting section76. The bolt88is inserted into one of the through holes87positioned above the fixing hole86according to the rotation position of the second supporting section76.

For example, by controlling the number, intervals, and the like of the plurality of through holes87, it also becomes possible to minutely control the rotation position of the second supporting section76. Since the fixing hole86is formed at a predetermined position, a fixing task of the bolt88becomes easy, and a check on whether the bolt88is fixed also becomes easy. However, the structure is not limited thereto, and a plurality of fixing holes86may be formed on the first supporting section75.

For example, a structure in which a hole is not formed on the first supporting section75and a retaining screw is inserted into a through hole formed on the second supporting section76so as to fix the second supporting section76may be adopted instead. With this structure, however, in a case where the retaining screw becomes loose due to oscillations and the like, there is a fear that the second supporting section76rotates accompanying the rotation of the plate-like section71. As a result, the rotation of the plate-like section71may not be restricted appropriately. In contrast, in this embodiment, since the second supporting section76can be fixed sufficiently using the bolt88, it is possible to sufficiently prevent the position of the second supporting section76from fluctuating.

In the projection apparatus100of this embodiment described heretofore, by providing the torque control section53, focusing can be executed with small torques and substantially the same torques when raising and lowering the observation section20. In addition, it becomes possible to prevent variations of the movement amounts due to the weight of the observation section20and maintain high operability for a significantly long period of time.

Other Embodiments

The present disclosure is not limited to the embodiment described above, and various other embodiments can also be realized.

In the descriptions above, the observation section20is raised and lowered by the elevating mechanism50. However, the stage40on which the work W is mounted may be raised and lowered. By applying the present disclosure also in this case, the stage40can be moved with high operability.

Further, the movement direction of the observation section20or the stage40(hereinafter, referred to as movement target section) is not limited to the longitudinal (vertical direction). The present disclosure is applicable also when moving the movement target section in an oblique direction that forms a predetermined angle with respect to the vertical direction. In this case, an upward oblique direction corresponds to the third direction defying the gravity, and the other direction corresponds to the fourth direction.

In the descriptions above, the first and second surfaces73and74of the plate-like section71are pressed by the first and second washer sections77and78so as to sandwich the plate-like section71. However, the method and structure for pressing the pressing members against the plate-like section71are not limited thereto. For example, torque control may be executed by pressing only one surface provided on the plate-like section. On the other hand, three or more surfaces may be provided on the plate-like section and pressed.

In the descriptions above, the first supporting section including the first surface and the second supporting section including the second surface are structured as separate members. Therefore, by changing the relative positions of those members, the distance between the first and second supporting surfaces can be changed easily. However, it is also possible to structure the first and second supporting surfaces such that the distance becomes changeable within a single member. In addition, the shaft section may be subjected to a hardening process so as to enhance an abrasion resistance and a fatigue strength.

In the descriptions above, the projection apparatus is exemplified as the optical apparatus according to the present disclosure. However, the present disclosure is also applicable to various optical apparatuses that perform observations and measurements using formed images of objects. Examples of such apparatuses include a digital microscope and various image measurement apparatuses.

In the descriptions above, the case where the user manually operates the handle is exemplified. However, the present disclosure is not limited thereto. The present disclosure is also applicable to a case where a motor is connected to the shaft section and the movement target section is moved by driving the motor. With this structure, highly-accurate focusing that uses the motor can be realized, and a load on the motor due to the weight of the movement target section can be reduced. Furthermore, since a motor torque requisite for raising and lowering can impart a certain amount of load to the movement target section when being raised and lowered, driving at a stable speed becomes possible.

At least two of the feature portions of the embodiments described above can be combined. In addition, the various effects described above are mere examples, and other effects may be exerted without limitations.