JPS60121410A - Positioning device - Google Patents

Abstract

PURPOSE:To position a sample in the direction of an optical axis and to move it in the direction vertical to the optical axis with high precision by providing a machanical stopper in a position of operation distance from an object lens and jetting compressed air from minute holes of this stopper to a surface to be measured to avoid shock of contacting between the mechanical stopper and the face to be measured. CONSTITUTION:A distance A between an object lens 2 of a microscope and a contacting face 14 of a mechanical stopper 15 is fixed to the operation distance determined by magnifications of the object lens 2. A sample 13 is placed on a sample stage 12, and an air cylinder 7 is moved in the direction of the optical axis of an arrow B to generate a gap between the contacting face 14 and a face 5 to measured while jetting air from minute holes 3 of the mechanical stopper 15, and air jetting is stopped, and thus, the contacting face and the face 5 to be measured are brought into contact with each other without shock by the repulsive force of a spring 6. When the sample 13 is moved in the direction vertical to the optical axis, air is jetted from minute holes 3 to generate a gap between the contacting face 14 and the face 5 to be measured, and the stage is moved in the direction of an arrow C in this state.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for positioning an object to be measured with high precision, such as focusing, in a microscopic dimension measuring device using a microscope.

Conventionally, the focus of a microscope has been adjusted using the following method. In other words, focusing in the optical axis direction is performed using a laser method or an air micrometer method to measure the distance between the microscope objective lens and the object to be measured with submicron accuracy, and then The drive system area that moves the objective lens up and down was achieved by feeding back to the drive system that moves the microscope tube that supports the objective lens up and down. Furthermore, even when updating the measurement location of the object to be measured, even without focusing, there are mechanical limits to the shape accuracy of the object to be measured and the performance of the stage's traversal (direction perpendicular to the optical axis). Since defocusing occurs and accurate measurements cannot be made, the above focusing has to be performed for each measurement location.

Therefore, such a method has the following problems.

■ In order to obtain highly accurate optical axis direction position information for both the laser method and the air micrometer method, a highly sensitive sensor must be used. Generally speaking, a highly sensitive sensor can only output a weak signal, so a high amplification factor is required. amplifier shall be used. Therefore, since there is always a problem with the electric circuit that reduces noise and increases the signal-to-noise ratio, the circuit tends to be complicated in order to obtain position information in the optical axis direction.

■ Even if temporary K and optical axis direction position information are obtained with high precision,
In order to keep the distance between the objective lens and the object to be measured within the focal length of the microscope, that is, the depth of focus, the drive system must be highly accurate, and it takes time to drive with feedback. Met. In the worst case, the driving may exceed the positional information in the optical axis direction, which may result in so-called divergence, in which optimal positioning cannot be achieved forever.

■ In order to reduce the time spent on focusing through feedback control, the stage that traverses the object to be measured needs to have high performance in traversing. Therefore, the stage is designed to be large, but it is possible to save space. It was easy to be at a disadvantage.

■ With this focusing method, the shape accuracy of the object to be measured,
In other words, since the parallelism is not zero, the measurement surface will not be perpendicular to the optical axis even if the stage is installed perpendicular to the optical axis, so it is possible that the area around the focused point will not be in focus. The accuracy of measurement is not affected by pressure.

In order to solve these five problems, the present invention provides high-precision positioning such as focusing of a microscope by providing a mechanical stopper in advance at a working distance from the objective lens, and attaching the mechanical stopper to the object to be measured. This is done by hitting an object against it, and in order to prevent scratches on the surface to be measured when the object to be measured hits it and moves in a direction perpendicular to the hitting direction, the mechanical stopper is provided with the above mechanical stopper. Compressed air is ejected from the surface to be measured through micro holes to create a gap between the mechanical stopper and the surface to be measured, thereby avoiding impact during abutment and mechanical contact during traverse movement, allowing for highly accurate positioning in the optical axis direction. This is a device that moves in a direction perpendicular to the optical axis.

The present invention will be explained below based on examples.

FIG. 1 is a diagram showing an embodiment for carrying out the present invention. In FIG. 1, the distance A between the objective lens 2 of the microscope and the contact surface 14 of the mechanical stopper 15 is the distance A between the objective lens 2 and the contact surface 14 of the mechanical stopper 15.
The working distance A is determined by determining the objective lens's 20 magnification.

On the other hand, a sample 13, which is an object to be measured, is placed on a sample mounting table 12 supported by an elastic member such as a spring 6, with the measurement surface 5 facing the contact surface 14 of the mechanical stopper 15. The spring 6 is used to compensate for the poor shape accuracy of the sample 13 and to keep the measurement surface 5 of the sample 13 and the contact surface 14 of the mechanical stopper 15 parallel. Further, the contact surface 14 of the mechanical stopper 15 is provided with a large number of microholes 3, so that the compressed air 1 can be supplied from behind.

The sample mounting table 12 is driven in the optical axis direction B by an air cylinder 7 or the like. The air cylinder 7 is moved by a CK motor 11 in a direction perpendicular to the optical axis direction B by means of a guide rail 8 and a ball screw 9.

FIG. 2 explains a method for positioning the object to be measured 13 in the optical axis direction B and moving it in a direction C perpendicular to the optical axis direction B. FIG.

In the same figure (a), the sample 13 is placed on the sample mounting stage 12.
4.

This is an example, and air is not blown out from the micro holes 3 of the mechanical stopper 15, and the contact surface 14 of the measurement surface 5 of the sample 13 and the mechanical stopper 15 is , they are not parallel as shown in the figure.

Next, as shown in FIG. 0), when the air cylinder 7 is moved in the original axial direction B while blowing out air from the micro holes 3 of the mechanical stopper 15, the air flow ejected between the contact surface 14 and the measurement surface 50 causes a slight A gap is created and the spring 6 automatically contracts so that the contact surface 14 and the measuring surface 5 are parallel. When this state is reached, the drive of the air cylinder 7 is stopped.

Then, when the air blowout from the mechanical stopper 1 and the microhole 3 is stopped, the gap created between the contact surface 14 and the measurement surface 50 due to the repulsive force of the spring 90 gradually disappears, and the contact surface 14 and the measurement surface 5 are affected by the impact. The result will be as shown in the same figure (C).

When moving the sample 13 in a direction perpendicular to the optical axis, the state shown in
Make more air blow out. Then, a small gap is created between the contact surface 14 of the stopper 15 and the measurement surface 5 of the material 13. In this state, operate the motor 11 to load the sample mounting table 1.
2 by a predetermined distance in the C direction, the measurement surface 5 of the material 13 can be moved without causing any scratches.

The present invention described above has the following effects.

■ Positioning is highly reliable as it does not require any sensors to provide position information and uses a mechanical stopper.

(2) Even though the positioning is performed at a high degree, the control is easy, so there are fewer occurrences of failures, and the operating time is increased accordingly.

■ Since it is not feedback control, there is no divergence and positioning can be done in a short time.

■ It can be used even if the shape accuracy of the sample is low.

(2) When changing the position of the sample to change the measurement point, the sample is moved while blowing air onto the measurement surface of the sample, so there is no possibility of scratches on the measurement surface of the sample.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a positioning device showing an embodiment of the present invention, and FIG. 2 is a diagram showing a positioning procedure. 1: Compressed air, 2: Objective lens, 3: Microhole, 4: Air flowing through the gap, 5: Measurement surface, 6: Spring, 7: Air cylinder, 8 Guide rail, 9: Ball screw, 10:
Air supplied to air pump, 11: Motor, 12:
Sample mounting stage, 13: Sample, 14.7. , 8. (0-) Snake Ru ÷ 1・

Claims (1)

[Claims] In a device for positioning an object to be measured in a measuring device using a microscope, a stopper is installed in front of the objective lens and has a contact surface that contacts the measurement surface of the object and has a large number of microholes. A table movable in the direction of the objective lens and a direction perpendicular thereto is provided in front of the surface, and a mounting base for placing the object to be measured is provided on the table with an elastic material interposed therebetween, and the contact surface of the stopper A positioning device characterized in that air can be blown out from micro holes provided in the.