JPH11271632A - Microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely perform automatic focusing without depending on the pattern or the like of a sample. SOLUTION: A light shielding body 19 in a comb shape is inserted to the position (surface indicated by a line A) of a light emitting part in a two-dimensional shape, and a surface light emitting part with the stripe pattern of a bright part and a dark part is formed. Irradiation light from the light emitting part is passed through an optical irradiation system 12 and exposed to a sample 14 and reflected light from the sample 14 is reflected by a half mirror 15, passed through an optical objective system 16 and made incident on a video camera 17. The value of a contrast function is calculated based on image data for one screen with brightness and darkness by the light shielding body 19 in an arithmetic processing part 24 and a control part 25 moves a stage 13 in the optical axis direction of the irradiation light so as to maximize the value of the contrast function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microscope for irradiating a sample with light and obtaining a magnified image of the sample by transmitted or reflected light, or for condensing infrared light on a small area of the sample and transmitting or reflecting the sample. The present invention relates to an infrared microscope for analyzing a sample by measuring a spectrum of infrared light, and more particularly, to an autofocus function in such a microscope.

[0002]

2. Description of the Related Art A microscope has a very shallow depth of focus as compared with a camera or the like and is difficult to focus manually. Therefore, an autofocus function is very useful. Therefore, the present applicant has already proposed an infrared microscope realizing an autofocus function in Japanese Patent Application Laid-Open No. 6-118296. In this infrared microscope, image data corresponding to an image of a sample is acquired by a video camera or the like, and a contrast function value representing the height of the contrast of the image is calculated based on the data, so that this value is maximized. The autofocus function is realized by moving the sample stage and optical system.

[0003] In the autofocus operation, an image of a sample is photographed by a video camera or the like using visible light, and thus such a method can be applied to a microscope other than the infrared microscope.

[0004]

However, in the autofocus function, when the image (eg, pattern) of the sample is not clear, when the sample is entirely white, or
When the entire sample is dark, the value of the contrast function is inaccurate, and it has been difficult to focus on the best state. Therefore, in such a case, it is necessary for the operator to manually perform focusing.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide an autofocus function capable of performing focusing without depending on an image of a sample. It is to provide a microscope.

[0006]

The microscope according to the present invention, which has been made to solve the above-mentioned problems, comprises: a) a light irradiating means for emitting visible light of a region of a predetermined size; An optical system for focusing light on the sample on the stage and forming an image of reflected light or transmitted light from the sample at a predetermined position; c) imaging means for outputting an image signal based on the formed image; d) light-shielding means, which is disposed so as to be freely inserted into the light beam emitted from the light irradiation means, and shields part of the light; e) changes the separation distance between the optical system and the stage; Moving means for moving at least one of the stages in the optical axis direction; andf) calculating a value indicating a contrast height of an image corresponding to the light shielding means based on an image signal output from the imaging means. Computing means; andg) inserting the light blocking means into the emitted light beam; By the computing means while changing the distance by serial moving means calculates the value, it is characterized by comprising a control means for said value to adjust the spacing distance so as to maximize the.

[0007]

In this configuration, when the light shielding means is at a position retracted from the emitted light beam, the light emitted from the light irradiating means passes through the optical system and strikes the sample, and the light reflected from the sample or transmitted therethrough. Light is condensed on the imaging surface of the imaging means by the optical system. Thus, an image signal corresponding to the image of the sample is output from the imaging unit.

At the time of the autofocus operation, the control means inserts the light-shielding means into the emitted light beam. As a result, the image pickup means outputs an image signal corresponding to the image of the light-shielding means, which has a part where the light is shielded by the light-shielding means and a part where the light passes without being shielded. Therefore, the control means obtains a value indicating the level of contrast by the arithmetic means while gradually changing the separation distance between the stage and the optical system by the moving means (for example, at every predetermined step). When this value is maximum, it can be determined that the focal point is in focus, so that the position of the stage and the optical system is determined at such a separation distance.

The light irradiating means may comprise a light source for emitting visible light and an appropriate optical system such as a condenser optical system. According to this, an image of the light source (for example, a filament image) can be diverged, and light can be apparently emitted from the light-emitting portion having a region of a predetermined size. This region may have a one-dimensional or two-dimensional spread.

[0010]

According to the microscope according to the present invention, an accurate image can be automatically obtained without being affected by various factors of the sample such as a case where the image of the sample itself is unclear, and a case where the whole sample is white or dark. Focusing is possible. For this reason, observation and analysis can always be performed at the in-focus point, and the labor of manual focusing conventionally performed when auto-focusing is not sufficient is reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An infrared microscope according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a main part of a reflection type infrared microscope of the present embodiment, and FIG. 2 is a schematic configuration diagram of the entire infrared microscope of the present embodiment. FIG. 1 mainly shows a configuration for realizing an auto-focus function in the infrared microscope, and is used for irradiating a sample with infrared light and extracting and detecting infrared light reflected from the sample. Optical systems and detectors are omitted.

First, the overall configuration of the infrared microscope according to the present embodiment will be described with reference to FIG. This infrared microscope is roughly composed of an infrared analyzer 1 and a personal computer 2. The infrared analyzer 1 irradiates a sample with infrared light and visible light, a stage 13 for mounting the sample, and converges light from the sample to form a sample image. Optical system for outputting the sample image as an electric signal. The imaging unit is a video camera when using visible light as a light source, and an infrared light detector when using infrared light as a light source. Note that in FIG.
Items other than 3 are omitted.

On the other hand, the personal computer 2
It comprises a main body 3 having a U or the like, a display 4 as display means, and a keyboard 5 and a mouse 6 as input means. Of course, other components such as a printer can be additionally provided as necessary. The electric signal output from the imaging unit of the infrared analysis unit 1 is processed in the main unit 3, and an image signal created based on the infrared spectrum or an image signal captured by a video camera is sent to the display 4. Thus, the screen of the display 4 shows the stage 1
An image 7 of the sample placed on 3 is displayed.

Next, the configuration relating to the autofocus function of the infrared microscope will be described in detail with reference to FIG. In FIG. 1, the optical system is mounted on a light source 10 that emits visible light, a light emitting unit optical system 11 for forming a surface light emitting unit, and a stage 13 that can be moved in the irradiation optical axis direction by a stage moving mechanism 18. An irradiation optical system 12 for irradiating the sample 14 with light, a half mirror 15 for extracting reflected light from the sample 14, a video camera 17 using a CCD image pickup device and the like.
And a light shield 19 that is inserted or retracted into the light beam of the irradiation light by the light shield moving mechanism 20, and the like. The light emitting unit optical system 11, the irradiation optical system 12, and the objective optical system 16 can be constituted by a so-called condenser optical system using a plurality of lenses and optical elements such as Cassegrain-type reflecting mirrors.

On the other hand, the electric system drives a video input section 21 for amplifying and A / D converting an image signal from the video camera 17, a stage driving section 22 for driving the stage moving mechanism 18, and a light shielding body moving mechanism 20. Shade driver 2
3. An arithmetic processing unit 24 for calculating a value representing a contrast of an image in an image captured by the video camera 17 by a process described later, a stage driving unit 22, and a light shielding unit driving unit 23.
And a control unit 25 for determining the focus position by judging the value calculated by the arithmetic processing unit 24 while controlling.

In the above configuration, prior to the analysis by irradiation with infrared light, an autofocus operation described later is executed,
Thereby, the stage 13 is moved to a position where both the irradiation optical system 12 and the objective optical system 16 are in focus.
In that state, for example, the irradiation optical system 1 is connected via a reflection mirror or the like.
When the sample 14 is irradiated with the infrared light having passed through the sample 2, the infrared light is focused on the sample 14, and the reflected light passes through the irradiation optical system 12 again (or passes through the objective optical system 16). ),
The light is sent to an infrared light detector by an infrared optical system (not shown).

The autofocus operation of the microscope having the above configuration will be described. Light emitted from the light source 10 is emitted from the light emitting unit optical system 11.
To form a surface light-emitting portion on which the image of the light source 10 is not projected on the plane indicated by the line A. At the time of the autofocus operation, the control unit 25 controls the light-shielding body moving mechanism 20 via the light-shielding body driving unit 23, and inserts the light-shielding body 19 into the optical path near the A-line. The light shielding body 19 has, for example, a comb shape as shown in FIG. 3A, and partially shields the light beam 30 forming the surface light emitting portion when inserted into the optical path. As a result, a portion through which light passes and a portion through which light is blocked occur, and FIG.
As shown in (b), a surface light-emitting portion in which the bright portion 31 and the dark portion 32 are formed in a stripe shape is formed. The shape of the light shield 19 is not limited to this, and may be an appropriate shape capable of forming a bright portion and a dark portion.

The control unit 25 controls the stage moving mechanism 18 via the stage driving unit 22 to move the stage 13 to a position farthest from the irradiation optical system 12. The light emitted from the above-described surface light emitting unit passes through the irradiation optical system 12 and irradiates the sample 14 on the stage 13. Sample 1
The reflected light from 4 passes through the objective optical system 16 after being reflected by the half mirror 15 and enters the video camera 17. The light incident on the video camera 17 is converted into an electric signal, whereby a luminance signal (image signal) corresponding to the image of the sample 14 is normally obtained. , A luminance signal in which a stripe pattern corresponding to is superimposed is obtained. Since such stripes usually appear more clearly than the image of the sample 14 itself, the video camera 17
An image substantially corresponding to the surface light emitting unit shown in FIG. 3B is obtained.

The luminance signal obtained by the video camera 17 is amplified by the video input section 21, converted into digital data, and sent to the arithmetic processing section 24 as image data. The arithmetic processing unit 24 has a data memory for accumulating image data for one screen, and when acquiring image data as described above, calculates a contrast value indicating the level of contrast of an image in one screen. I do. For example, among the image data for one screen, the maximum value of all the image data corresponding to the bright portion 31 of the surface light-emitting portion, and the minimum value of all the image data corresponding to the dark portion 32 of the surface light-emitting portion. Can be used as a contrast value. Then, the stage driving unit 2
The stage moving mechanism 18 is controlled via the
While approaching 3 to the irradiation optical system 12 by a predetermined moving amount, the contrast of the image with respect to the stage position Zn at that time is acquired as the value C (Zn) of the contrast function.

The control unit 25 calculates the value C of this contrast function.
(Zn) are sequentially received, and the magnitude is compared to find a position Zn where the contrast function is maximum.
When the contrast function is maximum, it can be determined that the light source 10 is in focus, so that the stage moving mechanism 1 moves the stage position Zn to that position.
8 is controlled. Here, a method of controlling the movement of the stage 13 to the position where the contrast function is maximized will not be described in detail.
The method disclosed in Japanese Patent Publication No. 296 can be used. Note that, as a contrast function, the bright portion 3 of the surface light emitting portion
Other functions indicating the height of the contrast of the image corresponding to 1 and the dark portion 32 may be adopted.

When the autofocus operation is completed as described above, the control section 25 controls the light-shielding body moving mechanism 20 via the light-shielding body driving section 23 to retract the light-shielding body 19 from the optical path. Accordingly, the light flux from the light source 10 is not blocked, and the image of the sample 14 can be displayed on the display 4 based on the image signal captured by the video camera 17. Further, if infrared light is irradiated instead of the visible light source 10 as described above, infrared light can be focused on a small area of the sample 14 and infrared analysis of the small area can be performed.

Although the above-described embodiment is a reflection type infrared microscope, a transmission type can also realize the same autofocus function. FIG. 4 is a diagram showing an optical path configuration in a transmission infrared microscope. In this configuration, the irradiation optical system 12 and the objective optical system 16 are disposed on both sides of the stage 13, and the light that has passed through the irradiation optical system 12 passes through the sample 14 and the stage 13, and 16 converges on the video camera 17.

The above embodiment is merely an example, and it is apparent that modifications and variations can be made within the spirit of the present invention.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of a reflection type infrared microscope according to one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of the entire infrared microscope of the present embodiment.

FIG. 3 is a schematic diagram showing a shape of a light shield and a state of a surface light emitting portion formed by the light shield.

FIG. 4 is a configuration diagram of an optical path of a transmission infrared microscope according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Light source 11 ... Light emitting part optical system 12 ... Irradiation optical system 13 ... Stage 14 ... Sample 15 ... Half mirror 16 ... Objective optical system 17 ... Video camera 18 ... Stage moving mechanism 19 ... Shielding body 20 ... Shielding body moving mechanism 21 ... Video input unit 22 Stage drive unit 23 Light shield drive unit 24 Arithmetic processing unit 25 Control unit

Claims (1)

[Claims] A) a light irradiating means for emitting visible light of a predetermined size area; and b) focusing the visible light on a sample on a stage, and reflecting reflected light or transmitted light from the sample on a predetermined level. An optical system for forming an image at a position, c) imaging means for outputting an image signal based on the formed image, and d) a part which is disposed so as to be freely insertable in the light beam emitted from the light irradiation means. E) moving means for moving at least one of the optical system and the stage in the direction of the optical axis so as to change the separation distance between the optical system and the stage; Calculating means for calculating a value indicating the level of contrast of an image corresponding to the light-shielding means based on an image signal output from the imaging means; andg) inserting the light-shielding means into the emitted light beam, and Calculating the value by the calculating means while changing the separation distance Microscope characterized by comprising a control means for said value to adjust the spacing distance so as to maximize the.