JP2578507Y2 - Scanning optical microscope - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical microscope.

[0002]

2. Description of the Related Art Conventionally, a scanning optical microscope for dividing light from a sample into two parts and detecting each light is disclosed in
There is a thing as shown in 1-219920 gazette,
Hereinafter, the configuration of the scanning optical microscope will be described with reference to FIG.

In FIG. 5A, a laser beam 2 from a laser 1 is expanded by a beam expander 3 into a light beam of an appropriate size. This laser beam passes through the polarizing beam splitter 4 and enters the first optical deflector 5. The first optical deflector 5 is disposed at a pupil position 53 conjugate with the pupil 10A of the objective lens 10.

The laser beam 2 deflected by the first optical deflector 5 passes through pupil transmission lenses 50 and 51, and is also placed at a pupil position 52 conjugate with the pupil 10 A of the objective lens 10.
Is incident on the optical deflector 6. This second optical deflector 6
If the scanning in the Y direction is performed in the dimensional scanning, the first optical deflector 5 performs the scanning in the X direction.

A laser beam two-dimensionally scanned by the first and second optical deflectors 5 and 6 is incident on a pupil 10A of an objective lens 10 by a pupil projection lens 7 and an imaging lens 8. These light beams are applied to the sample 1 by the objective lens 10.
1 produces a diffraction-limited point-like light. Further, the sample 11 is two-dimensionally scanned by the first and second optical deflectors 5 and 6 by scanning the point light on the sample 11 two-dimensionally.

In the figure, reference numeral 9 denotes a quarter-wave plate through which a laser beam incident on the pupil 10A from the imaging lens 8 passes.
It is used in combination with the polarizing beam splitter 4 to efficiently detect the reflected light from the sample 11. The laser beam reflected from the sample 11 passes through the objective lens 10 and its pupil 1
The light passes through 0A and further passes through the imaging lens 8 to form an image once. This imaging surface is a surface on which an image is observed with a normal optical microscope. Further, the laser beam returns to the optical deflector by the pupil projection lens 7.

As described above, the reflected beam returns to the polarizing beam splitter 4 through exactly the same path as when entering the sample, where it is reflected and passed through the lens 12 to the photodetector 13.
Is collected.

On the other hand, since the reflected light returns after passing through the first and second optical deflectors 5, 6, the reflected light incident on the lens 12 does not move even when scanning is performed off-axis. Since the first and second optical deflectors 5 and 6 and the photodetector 13 are located at the pupil position, the photodetector 13 is composed of two detectors 13a and 13b, and is arranged symmetrically with respect to the optical axis. For example, as shown in FIG. 5B, the reflected light flux does not move in either on-axis or off-axis scanning, so that differential observation is accurately performed.

[0009]

However, in such a conventional scanning optical microscope, accurate differential observation can be performed. However, the first optical deflector is provided by disposing the pupil transmission lenses 50 and 51. Since 5 is conjugated to the pupil 10A of the objective lens 10, there is a problem that the device becomes large.

Therefore, recently, a scanning optical microscope disclosed in JP-A-4-165325 has been proposed as a miniaturized scanning optical microscope. FIG. 6A shows a configuration example of an optical system of such a scanning optical microscope.
The same components as those in (a) are denoted by the same reference numerals, and description thereof will be omitted. Here, different points will be described.

In the optical system shown in FIG.
The pupil transmission lenses 50 and 51 existing in the optical system (a) are removed, and a position conjugate with the pupil 10A of the objective lens 10 is set at an intermediate position 60 between the first and second optical deflectors 5 and 6. Things.

Therefore, in the scanning optical microscope having such a configuration, since the pupil transmission lens is omitted, the size of the apparatus can be reduced, and when the reflected light of the sample 11 is simply observed, There is no particular problem.

However, when trying to perform differential observation, the first
And the second optical deflectors 5 and 6 are pupils 10A of the objective lens 10.
6B, off-axis light moves on the detector 13 as shown in FIG. 6B, and there is a problem that accurate differential observation cannot be performed. The present invention solves the above problems,
It is an object of the present invention to provide a scanning optical microscope capable of reducing the size of an apparatus and performing accurate differential observation.

[0014]

According to the present invention, a light source, a condensing lens for condensing light from the light source on an object, and a condensing lens disposed between the light source and the condensing lens are provided. A scanning optical system comprising: a first light deflecting element for deflecting light from the light source; and a second light deflecting element for deflecting light in a direction orthogonal to the direction of deflection of the first light deflecting element. A scanning optical microscope comprising a photodetector that divides reflected light, fluorescence, and transmitted light from an object into two at a conjugate position with a pupil position of the optical lens and detects each of the two lights; One of the deflection element and the second light deflection element is conjugated to the pupil position of the condenser lens, and the direction of a dividing line for dividing reflected light, fluorescence, and transmitted light from an object into two is defined as the pupil position. Set to be orthogonal to the scanning direction of the first or second optical deflection element conjugate with Is shall.

[0015]

Therefore, in the scanning optical microscope having such a configuration, the direction of division of the two detecting sections for detecting the reflected light, the fluorescent light, and the transmitted light from the object by dividing into two is always conjugate with the pupil position. Since it is located at a position orthogonal to the scanning direction of the first or second light polarizing element, not only on-axis light but also off-axis light can always be positioned on the dividing line, and accurate differential observation can be performed. Can be.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of an optical system of a scanning optical microscope according to the present invention. The same reference numerals are given to the same components as those in FIG. 5A, and the description thereof will be omitted. The point is described.

In this embodiment, as shown in FIG. 1, the first optical deflector 5 is located at a position 14 conjugate with the pupil 10A of the objective lens 10.
And the direction of the dividing line for dividing the reflected light from the object by the two detectors 13a and 13b of the photodetector 13 is orthogonal to the scanning direction of the first optical deflector 5 conjugate to the pupil position. Is set as follows. In this case, the second optical deflector 6 is not conjugate with the pupil 10A of the objective lens 10.

Next, the operation and effect of the above configuration will be described. First, when the first optical deflector 5 is disposed at a position 14 conjugate with the pupil 10A of the objective lens 10, the light beam when two-dimensional scanning is performed. The situation will be described with reference to FIGS. 2, 3, and 4. FIG. FIG. 2 shows a so-called axial light beam in the case of the scanning center. This is true for both light beams of the light deflectors 5 and 6 in FIG.

It is assumed that representative light beams of the incident light beam are 20, 21, 22. Of these, the central ray 20 travels on the optical axis, and the sample 2
It is reflected at 7 and returns to the same position. The light beam 21 is the light deflector 2
The light is reflected by 3 and enters a sample 27 through a pupil projection lens 24, an imaging lens 25, and an objective lens 26. The light reflected by the sample returns in exactly the same optical path as the incident light ray 22.
Similarly, the incident ray 22 returns in the same optical path as the incident ray 21 in reverse.

Therefore, the incident light and the reflected light coincide. Regarding the on-axis light, as is apparent from the figure, even if the conjugate position 28 of the pupil 26A of the objective lens 26 is on the optical deflector 23,
Even if they are not at the conjugate position (position 28 '), the incident light beam and the reflected light beam coincide.

FIG. 3 shows light rays in the case of an off-axis light beam. This applies to the light beam of the first optical deflector 5 disposed at a position 14 conjugate with the pupil 10A of the optical objective lens 10 in FIG. Note that the same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

The central ray 30 among the representative rays 30, 31, and 32 is deflected by the optical deflector 23,
The light enters the sample 27 through the imaging lens 25 and the objective lens 26. In this case, since the central ray 30 is perpendicularly incident on the sample 27, the incident optical path returns to the opposite direction. On the other hand, the incident light beam 31 enters the sample 27 at an angle, but the reflected light coincides with the optical path of the incident light beam 32. Similarly, the reflected light of the incident light beam 32 coincides with the optical path of the incident light 31. Therefore, when the optical deflector is located at a position conjugate with the pupil of the objective lens, the positions of the incident light beam and the reflected light beam coincide. Next, with reference to FIG. 4, a description will be given of a state of light rays when two-dimensional scanning is performed when the optical deflector is not disposed at a position conjugate with the pupil of the objective lens.

FIG. 4 shows the light beam of the optical deflector 6 shifted from the position 14 conjugate with the pupil 10A of the optical objective lens 10 in FIG. Note that the same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

Before the central ray 40 enters the optical deflector, it coincides with the optical axis 43 and enters the optical deflector 23. Then, the light is deflected by the optical deflector 23 and enters the sample 27 through the pupil projection lens 24, the imaging lens 25, and the objective lens 26. At this time, unlike the case of FIG. 3, since the light does not enter the sample 27 vertically, the reflected light returns as a reflected light ray 40 '. Therefore, the light beam reflected by the light deflector 23 and returned is shifted from the optical axis 43. The incident light beam 41 also enters the sample at a certain angle, but the reflected light becomes the incident light beam 41 ′ and does not coincide with the incident light beam 41. Similarly, the reflected light 42 of the incident light beam 42
'Does not coincide with the incident light beam. For this reason, a position shift occurs between the incident light beam and the reflected light beam. The amount of this shift varies depending on the angle of the optical deflector.

In this embodiment, in consideration of these characteristics, the dividing lines of the two detectors 13a and 13b constituting the photodetector 13 are made to coincide with the direction in which the light beam moves by scanning as described above. That is, the first optical deflector 5 performs scanning in the X direction and the second optical deflector 6 performs scanning in the Y direction, and the first optical deflector 5 is located at a position 14 conjugate with the pupil 10A of the objective lens 10. In some cases, if the dividing line of the photodetector 13 is set in the Y direction as shown in FIG. 1B, accurate differential observation can be performed as in FIG. 5B.

In the above embodiment, the case where the first optical deflector 5 is located at a position conjugate with the pupil 10A of the objective lens 10 has been described.
When it is located at a position 14 'conjugate with A, the dividing line of the two detectors 13a and 13b of the photodetector 13 may be set in the X direction as shown in FIG.

In the above embodiment, the reflected light is described. However, if the dividing line of the photodetector is set in the same manner as the reflected light, accurate differential observation can be performed for the light transmitted through the sample. In this case, it goes without saying that the position of the photodetector must be arranged at a position conjugate with the pupil of the objective lens.

[0029]

As described above, according to the present invention, it is possible to provide a scanning optical microscope capable of miniaturizing the apparatus and performing accurate differential observation.

[Brief description of the drawings]

FIGS. 1A and 1B show an embodiment of a scanning optical microscope according to the present invention, in which FIG. 1A is a configuration diagram of an optical system, and FIGS. 1B and 1C are diagrams illustrating a case where a dividing line of a photodetector is scanned.

FIG. 2 is an explanatory view of a state of a light beam of an axial light beam when two-dimensionally scanning an optical deflector located at a position conjugate with a pupil of an objective lens.

FIG. 3 is an explanatory view of a state of a light beam of an off-axis light beam.

FIG. 4 is an explanatory diagram of a state of a light beam when an optical deflector is not disposed at a position conjugate with a pupil of an objective lens.

FIG. 5 shows an example of a conventional scanning optical microscope, and FIG.
FIG. 2B is a configuration diagram of an optical system, and FIG. 2B is an explanatory diagram of on-axis light and off-axis light of a light beam reflected by a detector in which two detection units are arranged symmetrically with respect to the optical axis.

6A and 6B show an example of a conventional miniaturized scanning optical microscope, in which FIG. 6A is a configuration diagram of an optical system, and FIG. 6B is a reflection by a detector in which two detection units are arranged symmetrically with respect to an optical axis. FIG. 4 is an explanatory diagram of on-axis light and off-axis light of a light beam.

[Explanation of symbols]

Reference Signs List 1 laser 2 laser beam 3 beam expander 4 beam splitter 5 first optical deflector 6 second optical deflector 7 pupil projection lens , 8
... An imaging lens, 9 a quarter-wave plate, 10 an objective lens, 10A a pupil. 11 ... sample, 12 ... lens,
13 Detector, 13a, 13b Detector, 14, 1
4 ': Position conjugate with the pupil.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02B 21/00-21/36

Claims (1)

(57) [Scope of request for utility model registration] A light source, a condenser lens for condensing light from the light source on an object, a first light deflecting element disposed between the light source and the condenser lens and deflecting light from the light source; A scanning optical system having a second light deflecting element for deflecting light in a direction orthogonal to the deflecting direction of the first light deflecting element; In a scanning optical microscope including a photodetector that divides reflected light, fluorescence, and transmitted light into two and detects each light, any one of the first light deflecting element and the second light deflecting element is used. Is conjugated to the pupil position of the condenser lens, and the direction of the dividing line that divides the reflected light, the fluorescence, and the transmitted light from the object into two is the scanning direction of the first or second optical deflection element conjugated to the pupil position. A scanning optical microscope, wherein the scanning optical microscope is set so as to be orthogonal to the above.