RU2162616C2 - Laser projection microscope - Google Patents

Abstract

FIELD: quantum electronics, laser projection systems. SUBSTANCE: laser projection microscope can be used for non-destructive test of large integrated circuits, for inspection of processes of treatment of materials with concentrated energy fluxes in industry, for examination of microobjects in medicine and biology. It has laser amplifier, objective lens, TV camera matched with computer placed coaxially. Image of observed object is formed on receiving unit of camera with the use of image forming system. Image forming system can include three lenses. First and second lenses are rigidly fixed relative each other so that rear focus of first lens is matched to front focus of second lens, third lens is made fast with regard to receiving unit of image recording system. Distance l₁ from observed object to first lens is chosen from condition l₁>(f₁+f₂)×f₁/f₂, where f₁ and f₂ are focal distances of first and second lenses accordingly. With movement of observed object along optical axis image of object of observation is displaced after second lens and distance from it to third lens changes. By movement of system of first and second lenses with reference to third lens this distance is brought to initial state, that is size of image of observed object on receiving unit of TV camera is also brought to initial position. Required displacement of system of first and second lenses is strictly proportional to displacement of object of observation with proportionality factor K = (f₂/f₁)/(1-(f₂/f₁)). EFFECT: preservation of stable size of image of observed object on receiving unit with change of its position along optical axis and consequently increased accuracy of test. 2 dwg

Description

 The invention relates to the field of quantum electronics, namely to laser projection systems, and can be used for non-destructive testing of large integrated circuits, processes for processing various materials with concentrated energy flows in industry, the study of micro-objects in medicine and biology.

 A device is known for laser processing of objects with visual inspection in the lumen [1], comprising a screen arranged in series along the optical axis, a laser amplifier, two lenses and a reflector. A device for recording and observing objects [2] is also known, which contains an object placement element, a focusing optical system, a superradiant laser medium, a feedback mirror, a beam splitter, a quarter-wave plate, and a recorder.

 The disadvantage of these devices is the lack of a simple and convenient imaging system that allows you to keep the image size of the object under observation unchanged when its position is changed.

 Closest to the proposed device is a device for processing, recording and observing objects using a superradiant laser medium [3], containing a superradiant laser medium, on the one hand from which a focusing optical system and an object are installed along the optical axis, and on the other hand from a superradiant The laser medium has a beam splitting element, a reflecting element and a recording medium. The radiation of a superradiant laser medium is directed through a focusing optical system to an object and, after reflection from it, is returned to a superradiant laser medium using a focusing optical system, where it is amplified and then transmitted to a beam splitting element, which splits it into two parts, one of which is directed to the recording medium, and the other on the reflective element, which returns part of the radiation incident on it back into the superradiant laser medium and then through the focusing optical istemu to the object. However, using this device it is impossible to keep the image size of the object of observation on the recording medium unchanged when its position is changed.

 The problem solved by the invention is to maintain the image size of the observed object at the receiving device unchanged when changing its position along the optical axis and, as a result, increasing the accuracy of the control.

This problem is solved in that the laser projection microscope containing the coaxially mounted lens, the laser amplifier and the image recording system is equipped with a three-lens image forming system, the first and second lenses being rigidly fixed relative to each other so that the rear focus of the first lens is aligned with the front focus of the second lenses, the third lens is rigidly fixed relative to the receiver of the image registration system, the distance l ₁ from the observed object to the first lens is selected from the condition l ₁ > (f ₁ + f ₂ ) · f ₁ / f ₂ , where f ₁ and f ₂ are the focal lengths of the first and second lenses, respectively, and the system of the first and second lenses is made moving relative to the third lens in strict proportion to the movement of the object with a proportionality coefficient K = (f ₂ / f ₁ ) / (1- (f ₂ / f ₁ )).

Rigid fixing of the first and second lens relative to each other and rigid fixing of the third lens relative to the receiving device of the image registration system reduces the number of elements whose position must be adjusted, and thus facilitates the solution of the problem. The combination of the foci of the first and second lenses and the above ratio between the distance l ₁ from the observed object to the first lens with focal lengths f ₁ and f ₂ allows you to get a real image of the object of observation at the receiver of the registration system. The movement of the system of the first and second lenses is proportional to the movement of the object of observation with a proportionality coefficient K, which makes it possible to keep the size of the object of observation at the receiver of the registration system constant.

 In FIG. 1 shows a diagram of the proposed device.

 In FIG. 2 is a diagram of an image forming system.

 The laser projection microscope contains a laser amplifier 1, on one side of which the lens 2 and the object 3 of observation are located along the optical axis, and on the other hand, a television camera 4 connected to the computer 5, on the receiving device of which an image is formed using the image forming system 6 object 3 observation.

The device operates as follows. The radiation of a laser amplifier 1 operating in a super-luminosity mode (without mirrors) is focused on the observed object 3 using a lens 2. The radiation reflected from the object 3 of the observation is partially collected and sent to the input of the laser amplifier 1 with the same lens 2. Next, the radiation passes through the active medium laser amplifier 1, amplifying in it and using the image forming system 6, an image of the observed object 3 is formed on the receiving device of the television camera 4. The laser imaging system 6 The projection microscope is made three-lens (Fig. 2). The lenses F ₁ and F _{2 are} rigidly fixed relative to each other so that the rear focus of the lens F _{1 is} aligned with the front focus of the lens F ₂ . Then, under the condition l ₁ > (f ₁ + f ₂ ) · f ₁ / f ₃ , where l ₁ is the distance from the lens F ₁ to the image of the observed object h created by lens 2, f ₁ and f ₂ are the focal lengths of the lenses F ₁ and F _2, respectively, the image of the object after the lens F ₂ is imaginary, and its size h ₂ is constant and equal to h ₂ = h · f ₂ / f ₁ , where h is the size of the image created by lens 2, otherwise it is impossible to obtain an image h ₂ imaginary and inverted relative to the object 3 of observation, which is necessary to obtain a valid image h ₃ on the receiving device cameras 4. The lens F _{3 is} rigidly fixed relative to the stationary receiver of the camera 4. When moving the object 3 of the observation along the optical axis, the image h ₂ moves and the distance L from it to the lens F ₃ changes, which means that the size of the image h _{3 of the} object 3 of the observation on the receiver of the television camera 4. By moving the lens system F ₁ -F ₂ relative to the lens F ₃ by Δl _{3, the} distance L and the image size h _{3 are} restored to the initial state, and therefore, the image size of the observed object 3 on the receiver of the camera 4 h ₃ also cited in source. The required displacement Δl lens system ₃ F ₁ -F ₂ strictly proportional to the displacement Δl of the object ₁ and 3 cases linked to it by the relation Δl ₃ = K · Δl _1, wherein the proportionality coefficient K = (f ₂ / f ₁₎ / (1- (f ₂ / f ₁ )).

 The manufacture of the claimed laser projection microscope is possible at any enterprise focused on the manufacture of optical devices using traditional equipment.

Sources of information
1. A.S. USSR N 1583911, MKI G 02 B 21/00 / L.S. Glinkin, V.A. Gorbarenko, V.N. Epikhin, V.V. Korolev. Device for laser processing of objects with visual inspection in clearance; Claim 03.16.87. Publ. 07.08.90, BI N29.

 2. A. p. USSR N 1659960, MKI G 02 B 6/00 / Yu.P. Vasiliev, K.I. Zemskov, M.A. Ghazaryan, G.G. Petrash, V.V. Chvykov. Device for recording and monitoring objects; Claim 07.27.89, Publ. 06/30/91, BI N24.

 3. International application N WO 81/02951, MKI H 01 S 3/00; B 23 K 26/00 / K.I. Zemskov, V.A. Burmakin, V.V. Savin et al. A method for processing, recording and observing objects using a super-emitting laser medium and a device for its implementation; Claim 08/22/80, Publ. 10/15/81.

Claims (1)

A laser projection microscope comprising a coaxially mounted lens, a laser amplifier and an image recording system, characterized in that the microscope is equipped with a three-lens imaging system, the first and second lenses being rigidly fixed relative to each other so that the rear focus of the first lens is aligned with the front focus of the second lens , the third lens is rigidly fixed relative to the receiver of the image registration system, the distance from the observed object to the first lens l _{1 is} selected from the condition
l ₁ > (f ₁ + f ₂ ) f ₁ / f ₂ ,
where f ₁ and f ₂ are the focal lengths of the first and second lenses, respectively,
and the system of the first and second lenses is made moving relative to the third lens along the optical axis in strict proportion to the movement of the object of observation with a proportionality coefficient
K = (f ₂ / f ₁ ) / [1- (f ₂ / f ₁ )].

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