JP5070696B2 - Autofocus device and microscope having the same - Google Patents

Description

  The present invention relates to a microscope autofocus device and a microscope having the same.

Conventionally, in a biological microscope, a specimen is irradiated with illumination light with a slit-shaped light image, the observation position of the specimen is positioned at the front focal point of the objective lens using the reflected light, and the focus provided in the focus detection optical system An autofocus device that moves the front focal point of the objective lens relative to the sample by moving the position adjustment lens along the optical axis of the focus detection optical system and a microscope having the same are known (for example, Patent Document 1). reference).
JP 2004-70276 A

  However, in the autofocus device disclosed in Patent Document 1, when the focus position adjustment lens is moved along the optical axis of the focus detection optical system, the cover glass used for autofocus control or the cover glass and the specimen are used. It has been found that there is an objective lens that generates another light image (hereinafter referred to as stray light) other than the reflected image at the boundary surface. When autofocus control is performed using such an objective lens, autofocus control is performed based on erroneous focus detection information, and thus there is a possibility that the objective lens may collide with the specimen.

  The present invention has been made in view of the above problems, and provides an autofocus device including a focal position adjusting lens having a function of preventing a collision between an objective lens and a sample during autofocus control, and a microscope having the same. For the purpose.

In order to solve the above problems, the present invention provides:
A light source for focusing;
A focusing illumination optical system that forms an optical image based on light from the light source on an observation object via an objective lens;
A focusing imaging optical system that receives reflected light of the optical image from the observation object via the objective lens and forms a reflected image of the optical image on a light receiving surface of a photoelectric converter;
A focal position adjusting lens which is installed on the optical axis of the focusing imaging optical system and is movable in the optical axis direction;
In an autofocus device that adjusts the focal position of the objective lens according to a signal of the photoelectric converter,
Selectively inserted are different types of the stray light range and stray light stray light does not occur other than said light image of the objective lens for each objective lens is predetermined based on the boundary value of the range to be generated on the optical axis The objective lens collides with the object to be observed by restricting the movement of the focusing position adjusting lens in the optical axis direction of the focusing imaging optical system to a moving range of the focusing position adjusting lens that does not occur. providing an autofocus device comprising a benzalkonium be prevented.

  The present invention also provides a microscope having the autofocus device.

  ADVANTAGE OF THE INVENTION According to this invention, the autofocus apparatus provided with the focus position adjustment lens which has a function which prevents the collision of an objective lens and a sample at the time of autofocus control, and a microscope which has this can be provided.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a microscope equipped with an autofocus device according to the present invention. This microscope forms an enlarged image of a specimen that is an observation object, and is used for observation. As shown in FIG. 3 and the like, the specimen 18 that is an observation object is immersed in a medium such as water. In this state, it is placed between the cover glass 14 and the slide glass 15 and placed on the stage 11.

  In FIG. 1, an optical system of a microscope according to the present invention includes an observation optical system 3 disposed at the top of a specimen, and a focus illumination which is an optical system of an autofocus device according to the present invention disposed on the side thereof. An optical system 5 and a focusing imaging optical system 7 are included.

  The focusing illumination optical system 5 includes, on its optical axis, in order from the LED light source 20 side, a first collector lens 21, a slit plate 22, a second collector lens 23, a first pupil limiting mask 24, a first half mirror 25, A focal position adjusting lens 8 and a visible light cut filter 10 are arranged. A rectangular elongated slit aperture 22a is formed at the center of the slit plate 22, and the slit plate 22 is centered on the optical axis so that the longitudinal direction of the slit aperture 22a extends in a direction perpendicular to the paper surface in FIG. It is arranged.

  Infrared light (near infrared light) emitted from the LED light source 20 is collected by the first collector lens 21 and enters the slit plate 22, and the specimen surface (the boundary between the cover glass 14 and the medium in which the specimen is immersed). The second collector lens 23 converts the light into parallel light and irradiates the first pupil restriction mask 24.

  The first pupil restriction mask 24 shields half of the pupil, and is arranged so that half of the pupil is shielded along the longitudinal center line of the slit-shaped infrared light with the optical axis as the center. . The infrared light La that has passed through the first pupil restriction mask 24 passes through the first half mirror 25. The first half mirror 25 is disposed at a point where the optical axes of the focusing illumination optical system 5 and the focusing imaging optical system 7 intersect, and reflects a part of the infrared light, and the other A part of the light is transmitted through the focusing imaging optical system 7 as will be described later.

  A dichroic mirror 16 is disposed at a point where the optical axes of the focusing illumination optical system 5 and the observation optical system 3 intersect, and is shared by the observation optical system 3 as described later. The dichroic mirror 16 is disposed in an afocal system on the observation optical path of the observation optical system 3 and functions to reflect infrared light and transmit visible light and fluorescence. The infrared light La that has passed through the first half mirror 25 passes through the focal position adjusting lens 8, and then the visible light component contained in the infrared light La is removed by the visible light cut filter 10, and then reflected by the dichroic mirror 16. Then, it is reflected in the direction of the objective lens 12 (infrared light Lb), and is collected and irradiated on the sample by the objective lens 12. The objective lens 12 is shared by the observation optical system 3 as will be described later. The focus position adjusting lens 8 will be described later.

  The observation optical system 3 includes an objective lens 12, a dichroic mirror 16, an infrared light cut filter 18, a second half mirror 17, and a second objective lens 13 arranged in this order from the sample side. Although not shown, an eyepiece lens is disposed at the tip of the objective lens 13.

  Although not shown, an illumination device that illuminates the specimen placed on the stage 11 is provided. This illuminating device is of a transmission type or an epi-illumination type, and is disposed below the stage 11 in the case of the transmissive illumination device, and is disposed above the stage 11 in the case of the epi-illumination type illumination device.

  The light emitted from the illumination device passes through the specimen to become observation light, passes through the objective lens 12, passes through the dichroic mirror 16, and the infrared light is removed by the infrared light cut filter 18, and the second half mirror 17. Is incident on.

  A part of the observation light incident on the second half mirror 17 is reflected, and an observation image of the specimen is formed by the second objective lens 13 and the eyepiece, and is used for observation. Further, a part of the observation light transmitted through the second half mirror 17 passes through the camera objective lens 36 and the camera relay lens 37 to form an image on the imaging surface of the camera CCD sensor 38, and the camera signal processing unit 39. The sample image is projected onto a monitor (not shown).

  The focusing imaging optical system 7 receives slit-like infrared light that is irradiated and reflected from the specimen on the stage 11 by the focusing illumination optical system 5. Here, since the specimen on the stage 11 is covered with the cover glass 14, the infrared light for focus detection imaged by the objective lens 12 is the surface of the cover glass 14 or the boundary surface between the cover glass 14 and the specimen. Reflected at (sample surface). The infrared light reflected by the cover glass 14 or the sample surface is converted into parallel light by the objective lens 12 (infrared light Lc), reflected by the dichroic mirror 16 (infrared light Ld), and further, the visible light cut filter 10. And is incident on the first half mirror 25 that is disposed at an angle of approximately 45 degrees with respect to the optical axis of the focusing illumination optical system 5 and is partially reflected by the first half mirror 25. The light enters the focusing imaging optical system 7.

  The focusing imaging optical system 7 includes a first half mirror 25, an autofocus objective lens 26, an autofocus relay lens 27, and a second pupil restriction mask 28 in order from the focusing illumination optical system 5 side along the optical axis. An autofocus relay lens 27, a cylindrical lens 29, and an autofocus CCD sensor 30 are provided.

  The infrared light Ld reflected by the first half mirror 25 is condensed by the autofocus objective lens 26 and converted into imaging light to form a slit image. The autofocus relay lenses 27, 27 relay the slit image (infrared light Le) formed by the autofocus objective lens 26, pass through the cylindrical lens 29, and slit on the imaging surface of the autofocus CCD sensor 30. Reimage the image.

  The second pupil restriction mask 28 is disposed so as to shield half of the pupil, and the light-shielded area corresponds to the area shielded by the first pupil restriction mask 24. The cylindrical lens 29 is a lens having a refractive action only in a predetermined direction, and compresses the infrared light Le in a direction perpendicular to the paper surface (longitudinal direction of the slit image) in FIG. It functions to form an image on 30 imaging surfaces. The autofocus CCD sensor 30 can be composed of a line sensor in which a plurality of light receiving units are arranged one-dimensionally or an area sensor arranged in a two-dimensional manner.

  In the illumination optical system 5 for focusing, the light emitted from the LED light source 20 is formed into a slit shape through the slit aperture 22a of the slit plate 22, and the image of the slit aperture 22a is irradiated onto the sample. This is because when spot light is used, if there is a step on the sample surface, the reflected light is scattered and an ideal light quantity signal cannot be obtained. It is also possible to eliminate the plate 22 and perform autofocus control by irradiating the sample with the image of the LED light source 20 by the method described above. Further, this can be realized without the first collector lens 21.

  The focus position adjusting lens 8 used in the autofocus device according to the present invention will be described. As shown in FIG. 1, the focal position adjusting lens 8 is positioned on the common optical path of the focusing illumination optical system 5 and the focusing imaging optical system 7 between the dichroic mirror 16 and the first half mirror 25, and is an afocal system. It is arranged.

  A focal position adjusting lens driving unit 9 is attached to the focal position adjusting lens 8, and although not shown, a DC motor for the focal position adjusting lens that allows the focal position adjusting lens 8 to move back and forth along the optical axis. And an electric turret for a focus position adjusting lens that can exchange a plurality of focus position adjusting lenses 8 having different magnifications. The movement of the focal position adjusting lens driving unit 9 is controlled via a focal position adjusting lens movement control unit of the CPU 41 described later. Further, limit sensors HL1 (−) and HL2 (+) (see FIG. 5) for preventing collision between the objective lens 12 and the sample 18 when the focal position adjusting lens 8 is moved in the optical axis direction are provided. ing.

  Further, a focus position adjusting lens operation dial 51 for moving the focus position adjusting lens 8 along the optical axis and a focus position adjusting lens switching switch (not shown) are disposed in the input section of the microscope, which will be described later. When the position adjustment lens operation dial 51 is operated, the focal position adjustment lens 8 can be reciprocated along the optical axis based on a signal from an encoder 61 (see FIG. 6) coupled thereto. Further, an arbitrary focal position adjusting lens 8 can be selected and switched from a plurality of focal position adjusting lenses 8 mounted on the focal position adjusting lens electric turret by the focal position adjusting lens switching switch.

  The operation of the focus position adjusting lens 8 will be described with reference to FIGS. 2 and 3 show only components necessary for the description. In the figure, the illumination light for autofocus is indicated by a straight line, and the observation light in the observation optical system 3 is indicated by a dotted line.

  The focal position adjustment lens 8 shifts the imaging position a of the slit image (autofocus illumination light) focused and irradiated on the sample 18 by the objective lens 12 along the optical axis, and at the same time, reflects the sample 18 to reflect the auto image. It functions to shift the imaging position of the slit image re-imaged on the imaging surface of the focusing CCD sensor 30 along the optical axis.

  Hereinafter, a method for adjusting the focus f of the observation optical system 3 of the objective lens 12 to a position where the specimen 18 is actually observed while performing autofocus control will be described. The focal position adjusting lens 8 includes a convex lens 8a and a concave lens 8b, and one lens is fixed on the optical axis, and the other lens is arranged to be movable along the optical axis. As a modification, the convex lens 8a and the concave lens 8b may be configured to be movable along the optical axis. In the following description, the case where the convex lens 8a is fixed on the object side and the concave lens 8b is arranged behind the convex lens 8b so as to be movable along the optical axis will be described.

  As shown in FIG. 2A, the slit f in a state where the focus f of the observation optical system 3 of the objective lens 12 is aligned with the boundary surface between the cover glass 14 and the sample 18 (hereinafter referred to as “sample surface 14 b”). The focus position a of the autofocus slit image irradiated to the specimen 18 through the aperture 22a is also focused on the specimen surface 14b, and the reflected image is focused on the imaging surface of the autofocus CCD sensor 30. The position of the position adjusting lens 8 (concave lens 8b) is adjusted (this position is referred to as the “offset zero position” of the slit image by the focal position adjusting lens 8). In this state, the slit image is focused on the focal point f of the observation optical system 3 of the objective lens 12, that is, the sample surface 14 b, and the reflected light is focused on the imaging surface of the autofocus CCD sensor 30. In this state, the focal position adjusting lens 8 is simply a telephoto system, and the autofocus illumination light is a parallel light beam before and after the focal position adjusting lens 8. When auto focus control described later is applied in this state, the specimen surface 14b is always controlled so that the focus f of the observation optical system 3 of the objective lens 12 is in focus.

  Next, the focal position adjusting lens 8 (concave lens 8b) is moved back and forth along the optical axis to move the autofocus slit image, and the imaging position a of the autofocus slit image and the observation optical system of the objective lens 12 are moved. 3 is shifted (offset). For example, as shown in FIG. 2B, when the concave lens 8b is moved backward (in a direction away from the convex lens 8a) by a distance x, the imaging position a of the autofocus slit image is closer to the objective lens 12 than the sample surface 14b. It moves by a predetermined distance (this distance is called “offset amount OS”). In this state, when autofocus control, which will be described later, is performed, the sample surface 14b moves because the stage 11 moves, and the imaging position a of the autofocus slit image is set to the sample position as shown in FIG. It coincides with the surface 14b. At this time, the focal point f of the observation optical system 3 of the objective lens 12 moves into the sample by the offset amount OS, and can be made to coincide with a point P in the sample 18, for example, as shown in FIG.

  At this time, the moving amount x of the concave lens 8b constituting the focal position adjusting lens 8 and the offset amount OS on the specimen surface 14b are determined according to the magnification (focal length) of the objective lens 12. The offset amount OS necessary for the microscope apparatus is required to be about 50 μm due to the configuration of the specimen. In the case of an immersion objective lens, the reflectance of the lower surface of the cover glass is almost 0 when the medium is oil, and the same reflectance as that of the upper surface (specimen surface) is obtained when water is used. However, since the focal depth on the specimen side is very shallow, the reflection on the lower surface of the cover glass does not hinder the autofocus control. In addition, the autofocus device according to the present invention can cope with a general so-called dry objective lens, but in the case of a dry system, the reflectance of the lower surface of the cover glass is 10 times or more of the upper surface, and the depth of focus is relatively high. Since it is deep, it is difficult to set the upper surface of the original cover glass as the autofocus reference surface. Therefore, it is appropriate to use the lower surface of the cover glass 10 times or more as a signal as a reference surface. In this case, the offset amount is much larger than the offset amount (50 μm) of the high magnification / immersion objective lens (for example, the cover glass thickness 170 μm + 50 μm). A large offset amount can be set.

  As described above, the focal position adjusting lens 8 is composed of the convex lens 8a and the concave lens 8b, so that the focusing position adjusting lens 8 can be incorporated into a conventional autofocus device and the autofocus illumination light can be simply configured. The imaging position a and the focus f of the observation optical system 3 of the objective lens 12 can be offset.

  Note that the distance that can be shifted (offset) by the focal position adjusting lens 8 is physically limited by the focal length of the focal position adjusting lens 8, so that it is desired to shift beyond the physical limit. Can be handled by exchanging the focal position adjusting lens 8. For example, it is possible to realize a long shift amount by exchanging with a long focal length. When the focal position adjusting lens 8 is replaced with a lens having a different focal length, it is necessary to adjust the position of the focal position adjusting lens 8 in order to determine the position of zero offset.

  In the above configuration, the focal position adjusting lens 8 is disposed between the dichroic mirror 16 and the first half mirror 25, that is, on the common optical path of the focusing illumination optical system 5 and the focusing imaging optical system 7. The focal positions of the focused slit image and the slit image reflected by the sample 18 (sample surface 14b) and re-imaged on the imaging surface of the autofocus CCD sensor 30 are shifted in the optical axis direction. The focal position a of the slit image that is focused and irradiated on the specimen 18 between the first half mirror 25 and the first pupil limiting mask 24, that is, the focal position adjusting lens in the focusing illumination optical system 5, is the optical axis. It can also be realized by shifting in the direction. In addition, a focus position adjusting lens is disposed between the first half mirror 25 and the second autofocus objective lens 26, that is, in the focusing image forming optical system 7, so that the imaging surface of the autofocus CCD sensor 30 is re-applied. It can also be realized by shifting the focal position a of the slit image to be formed in the optical axis direction.

  The control system of the microscope includes an autofocus signal processing unit 31 for detecting a focus position, a stage driving unit 34 for moving the stage 11 up and down, an electric revolver driving unit 35 for driving an electric revolver for exchanging the objective lens 12, and It comprises a CPU 41, a memory 42, and an input unit 43 for controlling them.

  The slit image signal detected by the autofocus CCD sensor 30 is output to the autofocus signal processing unit 31 and processed by the CPU 41 to detect the focus information of the sample 18 with respect to the objective lens 12. A signal related to this focus information is sent to the stage drive unit 34 by the CPU 41, and the specimen is positioned at the focus f of the observation optical system 3 of the objective lens 12 by moving the position of the stage 11 up and down along the optical axis.

  It should be noted that the position where the slit image is formed on the imaging surface of the autofocus CCD sensor 30 corresponds to the position of the specimen 18 or the cover glass 14 that changes due to the vertical movement along the optical axis of the stage 11. Move in the short direction of the slit image. The moving direction of the stage 11 is controlled from the slit image detected by the autofocus CCD sensor 30.

  Although not shown in FIG. 1, the stage drive unit 34 includes a stage drive DC motor attached to the stage 11, a stage drive motor driver that rotates the stage drive DC motor, and a rotation angle of the stage drive DC motor. A rotary encoder to be detected and an up / down counter to count the vertical movement of the stage 11 based on the detection result of the rotary encoder.

  The autofocus control is processed by the CPU 41, and the control signals are output to the stage drive motor driver as a vertical movement control signal and a speed control signal, and the stage drive DC motor is driven based on these signals. The count result of the up / down counter is output to the CPU 41 as a vertical movement position signal. When the stage driving DC motor rotates, the stage 11 moves up and down along the optical axis according to the rotation angle. The specimen placed on the stage 11 also moves up and down together with the cover glass 14 and the slide glass 15, and the positional relationship between the specimen and the objective lens 12 is adjusted.

  Although only one objective lens 12 is shown in FIG. 1, the microscope of the present embodiment can be configured by a plurality of objective lenses 12 having different magnifications. Although not shown, the plurality of objective lenses 12 are attached to an electric revolver, and the electric revolver is connected to an electric revolver driving unit 35 that rotationally drives the objective lens. Although not shown, the electric revolver driving unit 35 includes an electric revolver driving DC motor attached to the electric revolver, and an electric revolver driving motor driver that rotates the electric revolver driving DC motor based on a rotation control signal from the CPU 41. Is provided. The electric revolver rotates according to the rotation of the electric revolver driving DC motor. Then, the plurality of objective lenses 12 attached to the electric revolver also rotate, and any one objective lens 12 is positioned on the observation optical path of the microscope. The electric revolver driving unit 35 is provided with a sensor (not shown) for detecting the number (1 to 6) of the revolver holes positioned on the observation optical path of the microscope among the revolver holes (for example, six) of the electric revolver. It has been.

  The input unit 43 includes a focus position adjustment lens operation dial 51, although not shown, a keyboard, an objective lens changeover switch, an autofocus control start switch, a focus position storage switch, an up / down fine adjustment switch, and the above-described focus position adjustment lens. The switch etc. which operate 8 are provided.

  The keyboard is used when inputting information of the plurality of objective lenses 12 set in the electric revolver. Each data of the plurality of objective lenses 12 input from the keyboard is stored in the memory 42. In-focus position information acquired by the in-focus position storage switch is also stored in the memory 42.

  The objective lens switching switch is used when switching the objective lens 12 positioned on the observation optical path of the microscope to another objective lens 12. The CPU 41 controls the electric revolver driving unit 35 based on the switching signal input from the objective lens switching switch, and positions the objective lens specified by the switching signal on the observation optical path of the microscope.

  The autofocus control start switch is used when instructing the start of autofocus control in the microscope. When the autofocus control start switch is operated, the CPU 41 starts executing the slit projection type autofocus control described above, and the sample 18 is positioned at the focal point of the objective lens 12.

  The up / down fine adjustment switch is used to finely adjust the vertical movement of the stage 11 by manual operation. The CPU 41 positions the stage 11 based on the fine adjustment signal input from the up / down fine adjustment switch. The up / down fine adjustment switch is operated while the operator observes the image of the specimen through the second objective lens 13 and the eyepiece of the microscope. Then, when an image with high contrast can be satisfactorily observed for the operator, the operation of the up / down fine adjustment switch is finished, and the stage 11 is positioned. At this time, in the microscope of the present embodiment, an arbitrary surface in the sample coincides with the focal point f of the objective lens 12.

  According to such a configuration, the focal position adjusting lens 8 is moved along the optical axis while performing autofocus control from the zero offset position, so that the focal position of the objective lens 12 can be freely adjusted and the specimen can be moved. Regardless of the amount of reflection of the autofocus slit image on the surface 14b, it can be shifted to an arbitrary position. Further, since the focal point f of the objective lens 12 can be focused at a position that is always away from the specimen surface 14b in the optical axis direction, the specimen 18 is moved on the stage and another part of the specimen 18 is observed. In this case, it is possible to perform an efficient work when the observation is performed after exchanging with another specimen 18.

  However, when the offset position OS is given by moving the focus position adjusting lens 8 along the optical axis, the reflected light from the focus detection slit image (see FIG. 4) depends on the type of the objective lens 12 inserted in the optical path. Reflected light other than S1) (S2 in FIG. 4) enters the focus detection optical system 7 as stray light and is detected by the autofocus CCD sensor 30. As a result, the autofocus control malfunctions, and the objective lens 12 and the sample 18 are detected. It has been found that there is a risk of collision. Here, FIG. 4 schematically shows an output from the autofocus CCD sensor.

The method of generating stray light due to the difference in the objective lens 12 is classified into the following three types.
(1) An objective lens that does not generate stray light over the entire moving range of the focal position adjusting lens 8.
(2) An objective lens in which stray light is not generated in a limited movement range of the focal position adjusting lens 8, and stray light is generated when the focal position adjusting lens 8 moves beyond this range.
(3) An objective lens that generates stray light in the entire movement range of the focal position detection lens 8.

  Among the objective lenses of the above classification (1) to classification (3), the objective lens of classification (3) cannot be used in the present autofocus control.

  On the other hand, the objective lens of category (1) is an objective lens suitable for this autofocus control, and until now, such an objective lens has been selected and used to prevent collision due to malfunction. However, since the objective lenses are selected and used in this way, there is a problem that the usable objective lenses are limited.

  The objective lens of classification (2) can be used in a limited range of movement. Therefore, by making the objective lens of this classification (2) usable, it becomes possible to widen the selection range of the objective lens. The autofocus device according to the present embodiment makes it possible to use the objective lens of classification (2) in addition to classification (1).

  In the autofocus device according to the present embodiment, the type (classification (1) to (3)) of the objective lens 12 inserted in the optical path is determined, and the focus detection malfunctions due to stray light, causing the objective lens 12 and the specimen 14 to malfunction. It is possible to prevent a collision with the. This is made possible by limiting the range of movement of the focal position adjustment lens 8 on the optical axis to a range where stray light does not occur, depending on the type of the objective lens 12.

FIG. 5 is a diagram conceptually showing processing for preventing a focus detection malfunction due to the movement of the focus position adjusting lens.
In FIG. 5, when the focus position adjusting lens 8 is moved, boundary values SL1 and SL2 between a range where stray light is not generated (range C in FIG. 5) and a range where stray light is generated (ranges B and D in FIG. 5). Is measured in advance for each objective lens and stored in the memory 42, and when the objective lens is selected, these values are read from the memory 42 to limit the movement range of the focal position adjusting lens 8, thereby autofocusing. It is possible to prevent malfunction of control. Here, SL1 and SL2 represent soft limit values that limit the movement of the focal position adjusting lens 8 in terms of software. A range C between SL1 and SL2 is a range in which stray light does not exist and autofocus control can be performed satisfactorily. HL1 and HL2 represent hard limit values, which are determined by the positions of sensors provided in the microscope. The mechanical limit mechanically restricts movement, and the focal position adjusting lens 8 cannot be moved beyond this limit.

  The offset zero position of the focus position adjusting lens 8 is set as the origin, and SL1 is set to the minus side and SL2 is set to the plus side soft limit value. For example, when the PlanApo DM20X (phase difference observation objective lens) is used as the objective lens 12, SL1 is minus 2.1 mm and SL2 is plus 2.2 mm with respect to the zero offset position.

  FIG. 6 is a control block diagram. Based on the objective lens replacement signal from the CPU 41, the electric revolver rotates and the selected objective lens 12 is inserted into the optical path. At this time, the CPU 41 reads the information such as the soft limit values SL1 and SL2 of the objective lens 12 selected by the sensor provided in the revolver hole from the memory 42 and sets the soft limit value of the focal position adjusting lens 8. Further, the position of the focal position adjusting lens 8 on the optical axis is determined based on the position information from the focal position adjusting lens driving unit 9. When the position of the focal position adjusting lens 8 is within the range C, the CPU 41 turns on the rotation signal ON / OFF 62 and based on the signal from the echoer 61 connected to the focal position adjusting lens operation dial 51, the focal position adjusting lens 8. Are moved in the plus or minus direction along the optical axis. When the position of the focal position adjusting lens 8 coincides with the soft limit SL1 or SL2, the rotation signal ON / OFF 62 is turned OFF and the movement of the focal position adjusting lens 8 is stopped regardless of the operation of the focal position adjusting lens operation dial 51. To do. In addition, the prosecutor is notified by an alarm (flashing of red light etc.) that the focal position adjusting lens 8 exceeds the movable range.

  Here, at the position of the soft limit SL1, the movement of the focal position adjusting lens 8 is stopped with respect to the operation of moving the focal position adjusting lens 8 from the range C in the range B direction, and the moving is performed with respect to the operation of returning to the range C direction. Control possible. On the other hand, at the position of the soft limit SL2, the movement of the focal position adjusting lens 8 is stopped with respect to the operation of moving the focal position adjusting lens 8 from the range C in the range D direction, and is movable with respect to the operation of returning to the range C direction. Controlled. When the focus position adjusting lens 8 exists in the range B or the range D, an alarm is displayed to notify the observer.

  As a result, the moving range of the focal position adjusting lens 8 can be limited to a region where no stray light is generated (range C) corresponding to the objective lens 12 inserted in the optical path, so that the objective lens 12 due to a malfunction of autofocus control. And the specimen 18 can be prevented from colliding with each other.

  FIG. 7 is a flowchart for explaining the interlocking of the focal position adjusting lens 8 when the objective lens 12 is switched.

(Step A1)
A signal is sent from the CPU 41 to the electric revolver, and the electric revolver is rotated via the electric revolver driving unit 35 to remove the objective lens 12 from the optical path.

(Step A2)
It is detected that another objective lens 12 is inserted into the optical path via the electric revolver driving unit 35.

(Step A3)
The signal from the address (sensor) of the revolver hole on the electric revolver is read, and the CPU 41 reads the relationship between the revolver hole and the objective lens 12 stored in advance in the memory 42, and determines whether the type of the objective lens 12 is unknown or known. do.

(Step A4)
If the objective lens 12 is unknown (the movable range (range C) of the focal position adjusting lens is not set), the display is made as indicating that autofocus control is impossible, and the switching process of the objective lens 12 is terminated.

(Step A5)
When the switched objective lens 12 is known, it is determined whether or not the movable range (range C) of the focal position adjusting lens 8 is set.

(Step A6)
When the movable range (range C) of the focal position adjusting lens 8 is not set, the focal position adjusting lens 8 is moved to the initial position (offset zero position), and the switching process of the objective lens 12 is ended.

(Step A7)
When the movable range (range C) of the focal position adjustment lens 8 is set, the focal position adjustment lens 8 is set to the position of the focal position adjustment lens 8 stored before switching of the objective lens 12, and further the focal position adjustment is performed. The movable range of the lens 8 is changed and the switching process of the objective lens 12 is ended.

  By performing the processing as described above, the movable range of the focal position adjusting lens 8 accompanying the replacement of the objective lens 12 can be automatically set, the collision between the objective lens 12 and the specimen can be prevented, and the replacement of the objective lens 12 can be performed. Can be performed quickly.

  As described above, according to the present invention, it is possible to use an objective lens having a moving range in which stray light is not generated when the focal position adjusting lens is moved, and the range of selection of the objective lens is widened. It becomes possible to provide an autofocus device and a microscope having the same.

  In addition, according to the present invention, it is possible to determine the movement range of the focal position adjustment lens for each objective lens, and it is possible to prevent collision between the objective lens and the specimen due to excessive movement of the focal position adjustment lens. It becomes possible to provide an apparatus and a microscope having the same.

  In addition, this invention is not limited to the said embodiment. In the embodiment of the present invention, the position of the focus position adjusting lens 8 is moved by the focus position adjusting lens operation dial 51, but it is also possible to operate it manually. Further, although the focal position adjusting lens 8 can be replaced in order to adjust the amount of shifting the focal position, it can also be realized with only the fixed focal position adjusting lens 8. According to such a configuration, the structure for adjusting the focal position can be simplified, the control system can be simplified, the autofocus device can be miniaturized, and the cost can be reduced.

  In the above embodiment, the stage 11 is moved up and down along the optical axis in order to focus the specimen 18 on the focal point f of the objective lens 12. However, the stage 11 is fixed and includes the objective lens 12. The observation optical system 3 may be configured to move up and down along the optical axis.

  The above-described embodiment is merely an example, and is not limited to the above-described configuration and shape, and can be appropriately modified and changed within the scope of the present invention.

It is a figure which shows typically the structure of the optical system and control system of the microscope which concerns on this invention. It is a figure showing the focusing state of a slit image when moving a focus position adjustment lens, (a) is a state of offset amount 0, (b) is a state when moving a focus position adjustment lens, (C) is a state in which the focal position is adjusted. It is a figure which shows typically the state by which the focus position was adjusted with the focus position adjustment lens. 2 schematically shows an image formation signal S1 and a stray light signal S2 in an autofocus CCD sensor. Fig. 4 schematically shows a movable range of a focus position adjustment lens. The block diagram of a focus position adjustment lens drive. It is a flowchart explaining the interlocking of the focus position adjustment lens 8 when the objective lens 12 is switched.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Observation optical system 5 Focusing illumination optical system 7 Focusing imaging optical system 8 Focus position adjustment lens 9 Focus position adjustment lens drive part 10 Visible light cut filter 11 Stage 12 Objective lens 13 Second objective lens 14 Cover glass 15 Slide glass 16 dichroic mirror 17 second half mirror 18 specimen 20 LED light source 21 LED light source 22 slit plate 23 second collector lens 24 first pupil restriction mask 25 first half mirror 26 autofocus objective lens 27 autofocus relay lens 28 second Eye limit mask 29 Cylindrical lens 30 Autofocus CCD sensor 31 Autofocus signal processing unit 34 Stage drive unit 35 Electric revolver drive unit 36 Camera objective lens 37 Camera relay lens 38 Camera CCD sensor Sensor 41 CPU
42 Memory 43 Input section 51 Focal position adjustment lens operation dial 61 Encoder 62 Rotation signal ON / OFF

Claims (5)

A light source for focusing;
A focusing illumination optical system that forms an optical image based on light from the light source on an observation object via an objective lens;
A focusing imaging optical system that receives reflected light of the optical image from the observation object via the objective lens and forms a reflected image of the optical image on a light receiving surface of a photoelectric converter;
A focal position adjusting lens which is installed on the optical axis of the focusing imaging optical system and is movable in the optical axis direction;
In an autofocus device that adjusts the focal position of the objective lens according to a signal of the photoelectric converter,
The stray light predetermined based on a boundary value between a range in which stray light other than the optical image of the objective lens is not generated and a range in which stray light is generated is different for each of different types of objective lenses selectively inserted on the optical axis. The objective lens collides with the object to be observed by restricting the movement of the focusing position adjusting lens in the optical axis direction of the focusing imaging optical system to a moving range of the focusing position adjusting lens that does not occur. An autofocus device characterized by preventing this.   2. The autofocus according to claim 1, wherein the limited movement range of the focal position adjustment lens is within a range of a mechanical limit that mechanically limits movement of the focal position adjustment lens in the optical axis direction. apparatus.   The different types of objective lenses used in the autofocus device may generate stray light over the entire moving range of the focal position adjusting lens corresponding to the objective lens inserted on the optical axis, or adjust the focal position. 3. The autofocus device according to claim 1, wherein stray light is not generated in a limited movement range of the lens. Storage means for storing the movement range for each of the plurality of objective lenses;
Objective lens exchanging means for exchanging the plurality of objective lenses on the optical axis;
Detecting means for detecting the objective lens arranged on the optical axis,
Before SL autofocus device according to the moving range corresponding to the sensed the objective lens by the detection means in any one of claims 1 to 3, and acquires from the storage unit.   A microscope having the autofocus device according to any one of claims 1 to 4.

Images