JPH02253221A - Autofocusing device for microscope - Google Patents

Abstract

PURPOSE:To perform accurate focusing even in the case of a substance whose reflected light quantity is not constant like a living body sample by changing the profile of a beam spot by the use of the focusing knob driving means of an objective lens and controlling so that the detected value may be the maximum brightness. CONSTITUTION:A laser beam 12 is inducted from an image-formation lens 4 and projected from the objective lens 2 to be converged on the surface of the sample 3. The reflected object light passes through a microscope 1 again and is inputted in a TV camera 6 through the image-formation lens 4. Based on data from the TV camera 6, the beam spot 13 is displayed on a CRT display device 7. The beam spot 13 of the TV image is scanned by a scanning line and data on the spread of beam sigma<2> and the intensity of beam Ip is transmitted to a CPU 10. Then, a step motor being the focusing knob driving means 11 is controlled with a control signal from the CPU 10 to adjust a focusing knob. It is a focusing state that Ip is maximum and sigma<2> is minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an autofocus device for a biological microscope.

``Prior art'' Autofocus devices in biological microscopes use triangulation autofocus using parallax in low magnification areas, and autofocus that maximizes the contrast and spatial frequency of a focused image. There is a device.

"Problems to be Solved by the Invention" Such a microscope autofocus device is based on the premise that an object (sample) exists within the field of view of the autofocus sensor. For this reason, it was necessary for the observer to move the sample stage and bring the object (sample) into the effective area of the autofocus sensor. This procedure is the same as the operation of placing an object in the focus sensor area of an autofocus single-lens reflex camera and pressing the shutter button.

When operating autofocus while moving the sample stage under computer control in a microscope, the sample may not come within the field of view of the autofocus sensor.

In this way, if there is no sample within the field of view (biological samples are developed on a glass slide, the sample is dispersed on the slide glass, and 2. There are many cases where there is no sample within the field of view), and the object is largely out of focus and cannot be seen. It cannot be determined whether the sample is missing or there is no sample, and it becomes impossible to focus.

The purpose of the present invention is to enable autofocus even when there is no sample within the field of view.

"Means for Solving the Problems" The present invention provides a means for introducing a light beam to be converged on the focal plane of an objective lens, a means for detecting the profile of a beam spot reflected from a slide glass or a sample on the slide glass, and an objective lens. and a control means for controlling the focus knob drive means so that the detection value of the profile detection means reaches a maximum brightness. It is.

"Operation" A beam such as a laser is introduced from the light beam introduction means, and the beam spot converged on the sample surface is detected by the profile detection means. Further, the focus knob is driven by the focus knob driving means of the objective lens to change the profile of the beam spot, and the control means outputs a control signal so that the detected value becomes the maximum brightness.

"Example" An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, (1) is a microscope equipped with a laser introduction device, and a sample (3) is set facing the objective lens (2) of this microscope fi (1), and the specimen (3) is set facing the imaging lens (4). Additionally, a light beam introducing means (5) such as a laser and a TV camera (6) are provided. This TV camera (6) has C
The RT display section (7) is combined to constitute beam spot profile detection means (8). Also, (9
) is an input means into which focus characteristics of various objective lenses are input. The input means (9) and the profile detection means (8) are coupled to a control means (10) such as a CPU, and a focus knob drive means (11) such as a step motor is connected to the output side of the control means (10). ) are combined. The control means (10) obtains control signals based on various types of information.

In the above configuration, the laser (12) is introduced through the imaging lens (4), exits from the objective lens (2), and converges on the sample surface (3). The reflected object light returns to the microscope 1.
! (1), passes through the imaging lens (4) and then passes through the TV camera (
6). Based on the data from the TV camera (6), the data is displayed on the CRT display device (7) as shown in FIG. It is assumed that the electric current p corresponding to the light intensity for the scanning line passing through the TV image beam spot (13) has a characteristic as shown in FIG. The position of the sample surface (3) is the objective lens (
The beam spot (
13) becomes the minimum diameter, but if the beam intensity p detected by the TV camera (6) becomes I p (
Xi, I i).

Bi 4 spread , x , XllX1” (Σ
l1Xi)”.

ΣIi ΣIi Beam intensity IP: Expressed as I&lX - Imin. Data on this beam spread σ2 and beam intensity IP are sent to CPU (10). In addition to these data, focus characteristics of various objective lenses are also input to the CPU (10) from an input device (9). Then, the step motor of the focus knob driving means (11) is controlled by a control signal from the CPU (10) to adjust the focus knob. That is, the position of the focus knob is determined by counting pulses sent to the step motor. As a result of moving the focus knob to either side, C
When the data Ip from the RT display device (7) decreases and σ2 changes to become slightly larger, the step motor (11) is slightly rotated in the opposite direction. After repeating this several times, when Ip is the maximum and σ2 is the minimum, the focus is in alignment.

"Effects of the Invention" Since the present invention is constructed as described above, it can be used even if the amount of reflected light is not a constant ratio as in the case of biological samples.

Accurate focusing is possible. Additionally, laser-introduced microscopes allow microscopic processing such as cells.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an autofocus device according to the present invention, FIG. 2 is a front view of a CRT display device,
FIG. 3 is a light intensity characteristic diagram. (1)...Microscope, (2)...Objective lens, (3)
...Sample surface. (4)...Imaging lens, (5)...Light beam introduction means, (6)...TV camera, (7)...CRT display section, (8)...Profile detection means, (9)...
Input means, (10)... Control means, (11)...
Focus knob driving means, (12)...laser, (1
3)...beam spot. Applicant: Hamamatsu Photonics Co., Ltd. Model Salesperson i-sho (spontaneous) July 26, 1989

Claims (2)

[Claims] (1) A means for introducing a light beam from the eyepiece side of the objective lens that converges on the focal plane of the objective lens, a means for detecting the profile of the beam spot reflected from the sample surface, and a focal point between the objective lens and the sample surface. A microscope autofocus device comprising: a focus knob drive means for adjusting the brightness; and a control means for controlling the focus knob drive means so that the detection value of the profile detection means reaches a maximum brightness. . (2) The microscope autofocus device according to claim (1), wherein the light beam introducing means comprises one for introducing a laser beam.