JP3419112B2 - microscope - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microscope, and more particularly to a method for adjusting the brightness of a light source for illuminating a sample in a microscope. In addition, the microscope referred to here is not only a normal microscope for obtaining an enlarged image of a minute sample, but also for measuring a transmitted or reflected infrared light spectrum by focusing infrared light on a minute portion of the sample. Includes an infrared microscope. 2. Description of the Related Art In order to make it easy to observe a sample with a microscope, it is necessary to appropriately set the brightness of a light source for illuminating the sample. Conventionally, an observer manually sets the brightness while looking through an eyepiece. Had been adjusted. [0003] However, it is complicated to manually adjust the brightness while looking through the eyepiece of the microscope. In addition, there is a demand for automation of operations for observation and analysis of a sample with a microscope, and microscopes having an autofocus function (function of automatically focusing) already exist, but in order to sufficiently meet the demand. Requires automation of brightness adjustment as well as focusing. Further, in the conventional microscope having the autofocus function, since the automatic focusing operation is performed independently of the brightness adjustment, the amount of illumination light is insufficient or excessive, and the contrast of the image of the sample may be abnormally low. is there. In this case, there arises a problem that the in-focus position cannot be detected, or the stage position (sample position) set by the in-focus operation deviates from the in-focus position. The present invention has been made to solve such a problem, and an object of the present invention is to provide a microscope capable of automatically setting the brightness of a light source for illuminating a sample to an appropriate value. Is to provide. [0005] In order to solve the above-mentioned problems, a microscope according to the present invention comprises: a) an optical device that is mounted on a stage and generates an image of a sample illuminated by a predetermined light source. B) imaging means for outputting an image signal representing the image generated by the optical system; and c) calculating a value indicating the level of contrast of the image based on the image signal output from the imaging means. Calculating means; d) luminance changing means for changing the luminance of the light source; e) moving means for moving the stage in the direction of the optical axis of the optical system; and f) moving and changing the luminance by the luminance changing means. By moving the stage, and calculating the value by a calculating means for various combinations of the brightness and the stage position, the brightness and the brightness at which the value is the maximum Control means for determining a combination with a stage position, setting the light source to the luminance in the determined combination by a luminance changing means, and moving the stage to the stage position in the combination by the moving means. It has a configuration. According to such a configuration, an image of the sample placed and illuminated on the stage is generated by the optical system, and an image signal representing the image is output from the imaging means. The control means changes the brightness of the light source illuminating the sample by the brightness changing means and moves the stage by the moving means, and calculates the value indicating the contrast of the image of the sample by the calculating means for various combinations of the brightness and the stage position. Is calculated. Then, based on the calculation result, a combination of the luminance and the stage position at which the value is maximized is obtained,
The light source is set to the luminance in the obtained combination, and the stage is moved to the stage position in the combination. Here, the stage position at which the value calculated by the calculation means is maximum can be regarded as the focus position. Therefore, by the above operation, the brightness is set so that the contrast of the image of the sample in the focused state is the highest. FIG. 1 is a diagram showing a configuration of a main part of an infrared microscope according to an embodiment of the present invention. This infrared microscope was used for sample 1
The objective optical system 13 is provided above the stage 11 on which 0 is mounted, and the condenser optical system 12 is provided below. The objective optical system 13 and the condenser optical system 12 are both composed of Cassegrain-type reflecting mirrors. As shown in FIG. 2, the stage 11 is moved between these two optical systems by a stage moving mechanism 18 using a stepping motor. Can be. Then, when performing infrared spectrum measurement by a focusing operation described later, the stage 11 moves to a position where the infrared light is condensed (the position of Zf in FIG. 2). At this position, both the objective optical system 13 and the condenser optical system 12 are in focus. Thereby, when measuring the spectrum of the infrared light reflected by the sample 10 (in the case of the reflection type measurement), the infrared light passing through the objective optical system 13 is condensed on the sample 10 and the red light reflected by the sample 10 is reflected. After the external light passes through the objective optical system 13 again, it is guided to a detector by an infrared optical system (not shown) and detected by the detector (not shown).
On the other hand, when measuring the infrared light transmitted through the sample 10 (in the case of the transmission type measurement), the infrared light transmitted through the condenser optical system 12 is focused on the sample 10 and the infrared light transmitted through the sample 10 is measured. After passing through the objective optical system 13, the light is similarly guided to the detector by the infrared light optical system, and is detected by the detector. In the infrared microscope, in order to move the stage 11 to the position where infrared light is focused as described above, focusing is performed using visible light prior to measurement of the infrared spectrum. The infrared microscope according to the present embodiment has an autofocus function, whereby the focusing is automatically performed. The configuration for realizing the autofocus function in this embodiment is basically the same as the configuration disclosed by the present applicant in Japanese Patent Application Laid-Open No. Hei 6-118296. That is, in the focusing, the sample 10
After passing through the objective optical system 13, the light is reflected by the mirror 14 and then enters the video camera 16. The light incident on the video camera 16 is converted into an electric signal,
A luminance signal (image signal) corresponding to the image of the sample 10 is obtained. This luminance signal is input to the electric system board. The electric system board includes a video amplifier 21, A /
It comprises a D converter 22, a static RAM 24, a DMA controller 25, a CPU 26, a motor driver 28, and a data bus connecting these. A luminance signal input from the video camera 16 to the electric system board is first amplified by a video amplifier 21 and then converted into a digital signal by an A / D converter 22. The value of the digital signal is image data corresponding to the image of the sample 10, and the image data is transferred from the A / D converter 22 to the static RAM 24 by the DMA controller 25 and stored therein. The CPU 26 calculates the value of the contrast function at the position of the stage 11 at that point (hereinafter referred to as “stage position”) from the image data for one screen. Then, based on the calculation result, the CPU 26 sends the stage moving mechanism 18 via the motor driver 28.
To the stage 11 toward the in-focus position.
To move. Here, the contrast function is a function of the stage position Zn. In this embodiment, the difference between the maximum value and the minimum value of one screen of image data corresponding to the image of the sample 10 on the stage 11 is determined by the value of the contrast function. And FIG. 4 is a diagram showing the shape of such a contrast function. As described later, the position (Zf in FIG. 4) where the contrast function is maximum is the focus position. As the contrast function, another function indicating the level of the contrast of the image of the sample 10 may be employed. In the infrared microscope according to the present embodiment, the brightness of the light source for illuminating the sample 10 (hereinafter referred to as "illumination light source") is automatically adjusted together with the above focusing. This point is different from the infrared microscope disclosed in JP-A-6-118296. In this embodiment, as shown in FIG. 1, a brightness adjustment driver 100 is connected to a data bus in an electric system board for automatic adjustment of the brightness. CPU2
6 adjusts the luminance by changing the voltage supplied to the illumination light source by the luminance adjusting driver 100. Hereinafter, the details of the operation for adjusting the luminance performed together with the focusing in the infrared microscope of the present embodiment will be described with reference to the flowchart shown in FIG. In the flowchart shown in FIG. 3, a variable n indicates the number of times the luminance of the illumination light source is changed, and L (n) indicates a value of the luminance after the change is performed n times. Note that L (0) indicates the minimum luminance value Lmin that can be set. In this embodiment, the CPU 26 performs focusing at each luminance while sequentially changing the luminance L of the illumination light source from the minimum value Lmin that can be set to the maximum value Lmax that can be set at predetermined intervals as described below. . First, in step S10, a variable n value is set to 0 (initialization), and in step S12, the luminance of the illumination light source is set to L (n). This setting is performed via the luminance adjustment driver 100 described above. After the luminance is set, focusing is performed in step S14. In this focusing, the CPU 26 controls the stage moving mechanism 18 via the motor driver 28 so that the value of the above-mentioned contrast function is maximized, that is, one screen at the luminance L (n). Stage 1 so that the difference between the maximum value and the minimum value of the image data (the image data represents the image of the sample 10) becomes maximum.
Move 1 In general, the contrast of the image of the sample 10 is highest when the position of the sample 10 is at the focus position, and the contrast decreases as the position of the sample 10 moves away from the focus position. Therefore, the amount of light for illumination becomes insufficient or excessive,
The stage position at which the value of the above-mentioned contrast function becomes the maximum is the focus position unless the contrast of the image is abnormally low or the like, and after the execution of step S14, the focus state is usually It has become. In step S16, the value of the contrast function and the position of the stage 11 after the execution of step S14,
That is, the maximum value FMX of the contrast function at the current luminance L (n) and the position Zf of the stage 11 at that time (see FIG. 4) are determined together with the luminance L (n) by the static R
Store it in AM24. In the next step S18, the current luminance L
The maximum value that can be set for (n) (hereinafter referred to as “maximum luminance”)
It is determined whether it is Lmax. If it is determined that the brightness is not the maximum brightness Lmax, the variable n is increased by 1 in step S24, and the process returns to step S12. Thereafter, S12 → S14 → S16 → until L (n) reaches the maximum luminance Lmax.
A loop of S18 → S24 → S12 is repeatedly executed. Thereby, focusing is performed at each luminance in the settable range Lmin to Lmax, and the maximum value of the contrast function (hereinafter, referred to as “maximum contrast value”) FMX at each luminance and the position Zf of the stage 11 at that time are as follows: Static RAM with corresponding luminance L (n)
24. In step S18, the current luminance L
When it is determined that (n) is the maximum luminance Lmax, the process proceeds to step S20. In step S20, the maximum contrast value FMX at each luminance stored in the static RAM 24 as described above is searched for. In step S22, the stage 11 is moved to the stage position stored together with the maximum maximum contrast value, and the illumination light source is set to the luminance stored together with the maximum maximum contrast value. For example, step S20
Assuming that the relationship between the luminance L stored in the static RAM 24 and the maximum contrast value FMX becomes as shown in FIG. 5 at the point in time when the process has proceeded to, the maximum maximum contrast value is FMXmax, and the corresponding luminance is Lf. It is. Therefore, in this case, the luminance of the illumination light source is set to Lf in step S22. When the luminance is set in step S22 in this way, the operation for luminance adjustment ends with the focusing operation. As can be seen from the above, according to this embodiment,
After the processing of the flowchart in FIG. 3 is performed, the brightness is set so that the maximum contrast value (maximum contrast function value) FMX becomes maximum at the stage position Zf where the value of the contrast function is maximized. Therefore,
The brightness is set so that the contrast of the image of the sample 10 in the focused state is the highest, and the set brightness can be considered as the brightness at which the sample is most easily observed, that is, the optimum brightness. Further, since the conventional automatic focusing operation is performed independently of the brightness adjustment, focusing may be performed in a state where the contrast of the image of the sample is abnormally low due to the shortage or excess of the illumination light amount. According to the present embodiment, focusing is finally performed at the luminance Lf at which the contrast is highest. Therefore, the in-focus state can always be achieved with high accuracy. According to the present invention, since the brightness of the light source for illuminating the sample is automatically set to an appropriate value, observation of the sample with a microscope and infrared microscopic measurement can be easily and efficiently performed. be able to. In addition, the automatic focusing operation is performed simultaneously with the automatic adjustment of the luminance, and finally, the focusing is performed at the luminance at which the contrast of the image of the sample is sufficiently high. There is also the advantage that it can be done.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a configuration of a main part of an infrared microscope according to one embodiment of the present invention. FIG. 2 is a diagram showing movement of a stage in the embodiment. FIG. 3 is a flowchart showing processing for brightness adjustment in the embodiment. FIG. 4 is a view showing a contrast function used in a focusing operation in the embodiment. FIG. 5 is a diagram showing the maximum contrast value at each luminance obtained by the processing for luminance adjustment in the embodiment. [Description of Signs] 10 試 料 Sample 11 ス テ ー ジ Stage 12 下部 Condenser optical system (lower Cassegrain) 13 上部 Objective optical system (upper Cassegrain) 16 ビ デ オ Video camera 18 ス テ ー ジ Stage moving mechanism 26 ＣＰＵCPU 28 モ ー タ Motor driver 100 輝 度 Brightness adjustment driver

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B 21/00 G02B 7/28

Claims (1)

(57) Claims 1. a) an optical system for generating an image of a sample mounted on a stage and illuminated by a predetermined light source; and b) representing the image generated by the optical system. Imaging means for outputting an image signal; c) calculation means for calculating a value indicating the level of contrast of the image based on the image signal output from the imaging means; and d) brightness change for changing the brightness of the light source. E) moving means for moving the stage in the direction of the optical axis of the optical system; f) changing the brightness by means of brightness changing means and moving the stage by means of moving means; By calculating the value by the calculating means for the combination of the above, a combination of the luminance and the stage position at which the value is the maximum is obtained, and in the obtained combination, And sets the luminance changing means said light source serial brightness, microscope, characterized by comprising a control means for moving by the moving means the stage to the stage position in the combination.