JPH1039199A - Focusing device applied to optical equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a focusing device having high focusing accuracy through the device is inexpensive and compact by deciding information on a distance between an objective lens and a stage based on the thickness of a plate member submitted to measurement and adjusting the distance between the object lens and the stage based on the decided information on the distance. SOLUTION: This device is equipped with an external controller 15 in order to control the start/stop of automatic focusing operation, input the thickness of a slide glass 2 by a microscopic observer and designate the magnification of the objective lens 3. A CPU 16 calculates the moving amount and the moving direction of the stage 1 based on the thickness of the slide glass 2 inputted by the controller 15 so that a sample S may be moved to the focusing position of an optical system, and gives the calculated results to a driving circuit 17 as a control signal. The driving circuit 17 performs focusing by moving in an up-and-down direction on the stage 1 based on the control signal from the CPU 16. Therefore, the influence of dust being the cause of the deterioration of the focusing accuracy in the case of automatic focus detection by an image processor is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus adjusting device applied to an optical instrument such as a microscope.

[0002]

2. Description of the Related Art Factors that reduce the focusing accuracy in automatic focus detection of a microscope include the influence of dust adhering to a subject and dust adhering to a plate member such as a slide glass or a cover glass on which a subject such as a biological tissue is placed. And / or the effects of dust adhering to a condenser lens that projects illumination onto the plate member.

[0003] Thus, the subject, the plate member, and / or
Alternatively, if there is an attached matter such as dust in an optical system such as a condenser lens as a typical example, thousands to hundreds of μm
The image of the deposit is mixed away. The image of this deposit is
The contrast is higher than that of the subject image. At this time, if the automatic focusing operation is performed, the attached matter is focused more on the object than on the subject, and there is a problem that the focusing accuracy for the subject is reduced.

[0004] Such a problem becomes more prominent in relation to the plate member used. That is, in the plate member, the standard slide glass conforming to the JIS standard has a thickness of 1.0 (−0.1 to +0.2) mm, and the cover glass has a thickness of 0.17 (−0.02 mm). ~
+0.01) mm. However, the plate member used for the microscope is not necessarily a standard slide glass and cover glass, but a slide glass and cover glass having a thickness different from that of the standard slide glass and cover glass depending on the wishes of the observer or the properties of the subject. May be used.

On the other hand, the distance between the upper surface position (reference focusing position) of the slide glass placed on the stage and the mounting position of the objective lens on the revolver is generally fixed. This constant value generally corresponds to the reference focal length: 45.
0 mm. In this case, with a standard slide glass having a thickness of 1.0 mm, the distance between the upper surface position of the stage and the mounting position of the objective lens on the revolver is 46.0.
(45.0 + 1.0) mm.

However, the distance between the upper surface of the stage and the mounting position of the objective lens on the revolver is 46.0 (45.
When the slide glass and cover glass having a thickness different from that of the standard slide glass and cover glass are used as they are at 0 + 1.0) mm, the upper surface position (reference focusing position) of the slide glass and the objective lens with respect to the revolver are used. The distance from the mounting position is a value shifted from the reference focal length of 45.0 mm. For this reason, when the automatic focusing operation is started when a slide glass and a cover glass having different thicknesses from the standard slide glass and the cover glass are used, the focusing accuracy for the subject may be reduced. This is because the automatic focusing operation is based on the reference focal length, which is a constant value. In addition, as described above, if an adhering substance is present on a plate member such as a slide glass, there is a problem that focusing accuracy on a subject, such as focusing on the adhering substance, is significantly reduced.

[0007]

As a prior art for solving such a problem, there is an area division type distance measuring system for selecting a place where there is no deposit applied to a video camera or an electronic still camera.

However, such a technique requires complicated control and image processing, and causes an increase in cost when applied to a microscope.
Therefore, an object of the present invention is to use a plate member having a different thickness or a case where there is a deposit on an optical system.
It is an object of the present invention to provide a practical focus adjustment device applicable to optical instruments, which can perform focus adjustment with high accuracy without being affected by these effects.

[0009]

The invention according to claim 1 is
An objective lens, a stage on which a plate member to be used for measurement on which a subject is placed, a providing unit for providing a thickness of the plate member to be used for the measurement, and a plate provided for the measurement provided by the providing unit Determining means for determining distance information between the objective lens and the stage based on a thickness of a member; and the objective lens based on distance information between the objective lens and the stage determined by the determining means. A focusing device for adjusting the distance to the stage, the focusing device being applied to an optical device.

According to a second aspect of the present invention, in the first aspect, the determining means detects an ambient temperature of the objective lens, and the temperature of the plate member used for the measurement provided by the providing means is determined by the detected temperature. The apparatus further comprises means for determining distance information between the objective lens and the stage based on the thickness.

According to a third aspect of the present invention, in the first or second aspect, the determining means determines a range in which the object is searched based on the thickness of the plate member provided for the measurement provided by the providing means. Means for determining the distance between the objective lens and the stage based on the determined search range.

According to the first aspect of the present invention, the distance information between the objective lens and the stage is determined based on the thickness of a plate member such as a slide glass or a cover glass. A focus adjustment device applied to an optical device, which is not affected by the thickness of the plate member or dust attached to the plate member, is inexpensive, is small, and realizes highly accurate focusing adjustment.

According to the second aspect of the present invention, the objective lens and the stage are based on the thickness of a plate member such as a slide glass or a cover glass and the ambient temperature of the objective lens detected by the temperature detecting means. Optical device that is not affected by the thickness of the plate member or dust attached to the plate member, is inexpensive, small, and achieves high-precision focusing adjustment. Can be provided.

According to the third aspect of the present invention, since the high-magnification objective lens has only a very small depth of field, it is difficult to determine the focusing position by the thickness of the slide glass. If the focusing zone is determined based on the thickness of the glass and automatic focus detection is performed by the image processing device, very high-speed and high-precision focus detection can be performed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention uses a plate member made of a slide glass or a cover glass. An object such as a biological tissue is placed on the slide glass, and a cover glass is put on the subject to form a specimen. , A microscope for observing the specimen. Such a microscope includes a stage on which the plate member is mounted, an observation optical system optically provided on the stage, an illumination optical system optically provided on the stage, and a thickness of the plate member used for the measurement. A setting unit that sets the distance, a determining unit that determines distance information between the objective lens and the stage of the observation optical system based on the thickness of the plate member that is provided for the measurement set in the setting unit, And a focusing unit that adjusts the distance between the objective lens and the stage based on the information on the distance between the objective lens and the stage determined by the determination unit.

A microscope as an optical apparatus according to a first embodiment of the present invention and an automatic focus detecting device applied thereto will be described below with reference to the drawings with reference to FIG.

The optical system of the microscope includes an observation optical system and an illumination optical system, and the microscope of the present embodiment has a transmission illumination optical system. As shown in FIG. 1, for an epi-illumination microscope that illuminates a specimen S composed of a slide glass 2, a subject 4, and a cover glass 5 placed on a stage 1 that can move up and down along the optical axis. And a transmission light source 6 'for a transmission microscope. The incident illumination light from the incident light source 6 is
The light passes through the collector lens 7, is reflected by the half mirror 8 toward the sample S, and enters the sample S through the objective lens 3 having a focal depth larger than the thickness of the subject 4. The transmitted illumination light from the transmitted light source 6 ′ passes through the collector lens 7 ′, is reflected toward the specimen S by the mirror 9 installed below the stage 1, and passes through the condenser lens 10 for the optical path opening of the stage 1. After passing through, the specimen S is illuminated from below.

A light beam from the sample S obtained by any one of the light sources 6 and 6 'passes through the objective lens 3 and the half mirror 8 constituting the observation optical system, enters the prism 11, and is guided to the eyepiece 12. I will When the prism 11 is contrasted from the optical path, the light beam passing through the half mirror 8 passes through the shutter 13 and enters the film surface 14.

Further, an external controller 15 is provided for controlling the start / stop of the automatic focusing operation, inputting the thickness of the slide glass 2 by the examiner, and specifying the magnification of the objective lens 3 and the like. The CPU 16 calculates the amount and direction of movement of the stage 1 to move the sample S to the focus position of the optical system based on the thickness of the slide glass 2 input by the external controller 15, and uses the calculated amount as a control signal as a drive circuit. Give 17 The driving circuit 17 uses the CP
Focus adjustment is performed by moving the stage 1 up and down based on a control signal from U16.

Next, the operation of the above embodiment will be described. FIG. 2 details the configuration in particular of the vicinity of the sample S in FIG. 1. The sample S composed of the cover glass 5, the subject 4, and the slide glass 2 is placed on the stage 1 that can move in the vertical direction. Have been. Here, the thickness of the slide glass 2 is ts, and the thickness of a reference slide glass 2A described later is ts.
It is assumed that the focal position of the objective lens 3 is at a fixed distance from the body mounting surface BF of the objective lens 3, for example, at a position of 45.0 mm, and this focal position is a reference focus position BP on the upper surface of the reference slide glass 2A. .

In order to focus on the upper surface of the slide glass 2 of the sample S, assuming that the upward direction in the drawing is plus, from the reference focusing position BP, Δt = t−ts (1) That is, it is only necessary to move the stage 1 by the amount.

Accordingly, if the thickness t of the reference slide glass has been input to the CPU 16 in advance, the speculum operator only needs to input the thickness ts of the slide glass 2 by the external controller 15, and the CPU 16 uses the above equation (1). Can be calculated from Δt. The CPU 16 outputs a control signal using the sign and the absolute value as the moving direction and the moving amount to the driving circuit 17.
And the stage 1 can be moved to achieve accurate focusing.

As described above, when the magnification of the objective lens 3 is relatively low and the depth of focus is deep, that is, when the thickness error of the slide glass 2 or the thickness of the sample S is smaller than the depth of focus of the objective lens 3. Works especially well for
The specimen S is obtained by focusing the surface of the slide glass 2.
Also falls within the depth of focus of the objective lens 3, so that an observation image with accurate focus can be obtained.

As described above, in the present embodiment, since no image processing or the like is performed, even if dust adheres to the cover glass 5 or the slide glass 2, it is not affected at all, and it is inexpensive, small, and highly accurate. Focusing is possible.

Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment is also a microscope having a transmission type illumination optical system as in FIG. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. In FIG. 3, a thermometer 18 for detecting an ambient temperature of the objective lens 3 is provided.
Are arranged, and the temperature data detected by the thermometer 18 is transmitted to the CPU 16.

In such a configuration, the CPU
The control operation by 16 is as follows. That is, FIG. 4 shows the objective lens 3 corresponding to the ambient temperature of the objective lens 3.
This figure shows the change characteristic of the distance from the body mounting surface BF to the sample focal position. From this characteristic diagram, the difference Δt _temp from the reference focus position due to the non-ambient temperature is represented by the following expression: Δt _temp = R × temp (2) ) Where R: temperature coefficient, temp: temperature ° C.

The CPU 16 performs an operation Δt = t−ts−Δt _temp (3) on the basis of the temperature data from the thermometer 18 and the thickness ts of the slide glass 2 input from the external controller 15, and from the calculated result, The moving direction and the moving amount of the stage 1 are determined, a control signal is transmitted to the drive circuit 17, and the stage 1 is moved.

As described above, since the distance from the body mounting surface BF of the objective lens 3 to the sample focal position is corrected by detecting the ambient temperature of the objective lens 3, compared with the case of the first embodiment. The focusing accuracy can be made higher.

Next, a third embodiment of the present invention will be described with reference to FIG. This embodiment is also a microscope having a transmission-type illumination optical system as in FIGS. 5, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. In FIG. 5, a slide glass thickness detector 19 for detecting the thickness of the slide glass 2 constituting the specimen S mounted on the stage 1 is arranged, and the slide glass detected by the slide glass thickness detector 19 is provided. 2 thickness data
The data is transmitted to the PU 16. The slide glass thickness detector 19 measures the thickness of the slide glass 2 placed on the stage 1 or previously measures the thickness of the slide glass 2.
The thickness ts of the slide glass 2 is detected by reading the bar code indicating the thickness attached to the upper end of the
Send to PU16.

The CPU 16 calculates Δt from the thickness ts from the slide glass thickness detector 19 and the thickness t of the reference slide glass 2A set in advance by using the above equation (1). By generating a control signal from the obtained result and sending it to the drive circuit 17, the stage 1 can be moved to the drive circuit 17 and accurate focusing can be achieved.

As described above, in the focus adjustment of this embodiment, since image processing and the like are not performed as in the second embodiment, even if dust adheres to the cover glass 5 or the slide glass 2, there is no influence. In addition, it is possible to provide a high-precision focusing device while being inexpensive and small, and it is possible to eliminate the trouble of the speculative person inputting the thickness of the slide glass 2 from the external controller 15. Reduced, easier to handle and excellent in workability.

Next, a fourth embodiment of the present invention will be described with reference to FIG. This embodiment is also a microscope having a transmissive illumination optical system as in FIGS. 1, 3, and 5. 6, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. This embodiment is an embodiment in which the configurations of the second embodiment and the third embodiment are combined. As shown in FIG. 6, by detecting the ambient temperature of the objective lens 3, the distance from the body mounting surface BF of the objective lens 3 to the sample focal position is corrected,
It is possible to reduce the burden on the examiner by reducing the burden on the observer by inputting the thickness of the slide glass 2 from the external controller 15 while improving the focusing accuracy, and is easier to handle and excellent in workability. It is also possible to make it.

In the first to fourth embodiments,
In any case, the vertical position of the stage 1 is moved by driving the drive circuit 17 based on a control signal from the CPU 16 to change the relative distance between the objective lens 3 and the stage 1, but this is not restrictive. Alternatively, the configuration may be such that the side of the objective lens 3 is moved.

Next, a fifth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the CPU 16, the drive circuit 17, the thickness detection unit 20 for detecting the thickness of the slide glass, the control of start / stop of the automatic focusing operation, etc., and the spectator specify the magnification of the objective lens, etc. An external controller 15 is provided. A thickness detection unit 20 for detecting the thickness of the slide glass 2 is provided on the stage 1 in Kremmel for holding the slide glass 2. The thickness t of the slide glass 2 output from the thickness detection unit 20 is input to the CPU 16, and the CPU 16 determines the position of the stage 1 based on the thickness t and the magnification data of the objective lens 3 input from the external controller 15. The movement amount and movement direction signals are calculated and transmitted to the drive circuit 17. The drive circuit 17 raises and lowers the stage 1 based on a signal from the CPU 15 and performs focus adjustment.

Next, the structure of the Kremmel having a built-in thickness detector 20 for detecting the thickness of the slide glass 2 will be described with reference to FIGS. FIG. 8A is a top view of the crememel of the present invention, and FIG. 8B is a side view of the crememel of the present embodiment.

As shown in FIG.
Are mounted on the guide 1A of the stage 1 by screws 21A. The guide 1A is slidable in the direction of the arrow with respect to the stage 1. Klemmer body 2
1 includes a holding metal fitting 22 for holding the slide glass 2 and a holding metal fitting 2 for holding down and fixing the slide glass 2 from above.
3. A rotary variable resistor 24 and a base 21B are provided. The base 21B is mounted on the Kremmel main body 21 with screws 21C. The rotary variable resistor 24 is mounted on a base 21B with a screw 24A. Further, a torque screw 25 for pressing down the slide glass 2 from above with a certain constant force is a rotary variable resistor 2.
4 and a gear 26. This torque screw 2
Reference numeral 5 is such that the slide glass 2 is pressed from above by a certain load, and cannot be pressed with a load higher than that. Note that the mechanism for moving the crememel may be omitted, and the crememel may be directly fixed to the storage 1.

The sample S composed of the subject 3, the cover glass 4 and the slide glass 2 is placed on the stage 1, and the slide glass 2 is fixed with the holding metal 22 and the holding metal 24. The tip of the torque screw 25 hits the surface of the slide glass 2 and is rotated until it stops. At this time, the variable resistor 24 also rotates, and the resistance value changes according to the thickness of the slide glass 2. By always pressing down the slide glass 2 with a constant pressure, the resistance value r at that time is detected, so that a highly accurate value can be obtained.

Next, the operation of the present embodiment will be described. When a start signal of the automatic focusing operation is sent from the external controller 15 to the CPU 16, the CPU 16
4 is read. The CPU 16 calculates the thickness t of the slide glass 2 based on the resistance value r. The external controller 15 has an objective lens 3 used in advance.
Enter the magnification data of.

First, a case where a low-magnification objective lens 3 having a depth of a subject larger than the thickness of the subject 3 is set will be described with reference to FIG. It is assumed that the thickness of the reference slide glass is t (the thickness t of the reference slide glass 27 is input to the CPU 16 in advance). The focal position of the objective lens 3 is a fixed distance 1 from the surface of the objective lens body. This position is defined as a reference focus position on the upper surface of the reference slide glass 27.

[0040] focusing on the upper surface of the slide glass 2 of the specimen, from the reference focus position, it is sufficient to move the Δt = t-t _s Stage 1. When the thickness t of the slide glass 2 is calculated by the CPU 16, Δt is obtained,
A signal of the moving amount and the moving direction of the stage 1 is transmitted to the drive circuit 17. The stage 1 starts moving to the in-focus position based on the signal. Therefore, there is no influence of dust which causes deterioration of the focusing accuracy of the automatic focus detection by the image processing apparatus, and high-accuracy focus detection can be performed.

Since the distance from the body surface of the objective lens 3 to the focal position is constant, if the stage position corresponding to the thickness is stored as data of the CPU 16, the thickness of the reference slide glass can be reduced. The stage 1 can be moved to the in-focus position without setting the external controller 15.

When the high-magnification objective lens 3 is set, it has a very small depth of field, and it is difficult to determine the focus position by the thickness of the slide glass 2. However, the focusing zone of the objective lens 3 can be determined by the thickness of the slide glass 2. Therefore, if the automatic focus detection is performed by the image processing device in the focusing zone determined by the thickness t of the slide glass, it is possible to perform the focus detection at a very high speed and with high accuracy.

Next, a sixth embodiment of the present invention will be described with reference to FIGS. The configuration of the automatic focus detection device for a microscope according to the present embodiment is the same as that of the fifth embodiment. FIG. 9A is a top view of the crememel of the present embodiment,
FIG. 9B is a side view. As shown in FIG. 9, the Kremmel main body 21 includes a holding fitting 22 for holding the slide glass 2, a holding fitting 23 for holding the slide glass from above, and a torque screw 25 for holding the slide glass from above with a certain force. Is provided.

The torque screw has a disk shape of several tens to
A micrometer 28 having a scale of several hundred micrometer is provided, and a reading device 29 for reading the micrometer 28 is installed in the Kremmel main body 21. The torque screw 24 presses the slide glass 2 from above with a certain load, and cannot press the slide glass 2 with a higher load.

First, in a state where the sample S is not set, the torque screw 25 is rotated until the tip of the torque screw hits the stage and stops. Micrometer 28 at this time
Is read by the external controller 15 and stored as a reference position. Then, the sample S composed of the subject 3, the cover glass 4, and the slide glass 2 is placed on the stage 1
The slide glass 2 is fixed on the slide glass 2 with the holding metal fitting 22 and the holding metal fitting 23.

The tip of the torque screw 25 is the slide glass 2
Rotate until it hits the surface and stops. At this time, the micrometer 28 with the scale is also rotated. By holding down the slide glass 2 with a constant pressure,
Since the scale at that time is detected, a highly accurate value can be obtained.

Next, when a start signal of the automatic focusing operation is sent to the CPU 16 from the external controller 15, the CPU 1
Reference numeral 6 reads the scale moved from the reference position from the reading device 29, and detects the thickness of the slide glass 2. The CPU 16 calculates the direction of movement of the stage 1 based on the thickness, and transmits a signal to the drive circuit 17. as a result,
Stage 1 starts moving to the in-focus position.

Thus, the same effects as in the fifth embodiment can be obtained. Next, a seventh embodiment of the present invention will be described with reference to FIGS. The configuration of the automatic focus detection device for a microscope according to the present embodiment is the same as that of the fifth embodiment. FIG. 10A is a top view of the crememel of the present embodiment,
FIG. 10B is a side view. As shown in FIG. 10, the Kremmel main body 30 is provided with a holding member 23 for holding down and fixing the slide glass from above. Sensor 31 is embedded. The specimen S composed of the subject 3, the cover glass 4 and the slide glass 2 is placed on the stage 1 and pressed to the abutment position A of the Kremmel main body 30. Also, at this time, the holding bracket 23
, The slide glass 2 is fixed.

When a signal for starting the automatic focusing operation is sent from the external controller 15 to the CPU 16, the CPU 16 reads the thickness of the slide glass 2 detected by the displacement sensor 30 incorporated in the Kremmel main body 30. CPU
16 calculates the moving amount and moving direction of the stage 1 and sends a signal to the driving circuit 17. Stage 1 based on that signal
Starts moving to the in-focus position. Thereby, the same effect as in the fifth embodiment can be obtained.

[0050]

As described above in detail, according to the present invention, the influence of dust adhering to a slide glass, a cover glass or the like is eliminated, and a focus which is inexpensive, compact and has high focusing accuracy and is applied to optical equipment. An adjustment device can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration according to a first embodiment of the present invention.

FIG. 2 is a diagram detailing a configuration near a specimen according to the embodiment;

FIG. 3 is a diagram showing a configuration according to a second embodiment of the present invention.

FIG. 4 is a view showing a relationship between an ambient temperature of the objective lens and a distance from a mounting surface of the objective lens to a position between a sample focal position according to the embodiment;

FIG. 5 is a diagram showing a configuration according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a fourth embodiment in which the second embodiment and the third embodiment of the present invention are combined.

FIG. 7 is a diagram showing a configuration according to a fifth embodiment of the present invention.

FIG. 8 is a top view and a side view of a crememel according to a fifth embodiment of the present invention.

FIG. 9 is a top view and a side view of a crememel according to a sixth embodiment of the present invention.

FIG. 10 is a top view and a side view of a cleanmel according to a seventh embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Stage 2 ... Slide glass 2A ... Reference slide glass 3 ... Objective lens 4 ... Subject 5 ... Cover glass 6 ... Epi light source 6 '... Transmission light source 7, 7' ... Collector lens 8 ... Half mirror 9 ... Mirror 10 ... Condenser lens DESCRIPTION OF SYMBOLS 11 ... Prism 12 ... Eyepiece 13 ... Shutter 14 ... Film surface 15 ... External controller 16 ... CPU 17 ... Drive circuit 18 ... Thermometer 19 ... Slide glass thickness detector 20 ... Thickness detector 21 ... Crammel body

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yukiko Saeki 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd.

Claims (3)

[Claims] 1. An objective lens, a stage on which a plate member to be used for measurement on which an object is placed is mounted, an application means for applying the thickness of the plate member to be used for the measurement, and the measurement provided by the application means Determining means for determining the distance information between the objective lens and the stage based on the thickness of the plate member provided for, and based on the distance information between the objective lens and the stage determined by the determining means. A focusing unit for adjusting a distance between the objective lens and the stage. 2. The method according to claim 1, wherein the determining unit detects an ambient temperature of the objective lens, and determines the temperature of the objective lens based on the detected temperature and a thickness of a plate member provided for the measurement provided by the providing unit. The focus adjustment apparatus applied to an optical apparatus according to claim 1, further comprising a unit that determines information on a distance from the stage. 3. The determining means determines a range for searching for the subject based on a thickness of a plate member provided for the measurement provided by the providing means, and determines the range based on the determined search range. 3. The focus adjustment device applied to an optical apparatus according to claim 1, further comprising a unit that determines information on a distance between an objective lens and the stage.