JP2007304103A - Spectroscope and confocal optical system using it, and scanning optical microscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spectroscope whole of which can compactly be assembled and a confocal optical system using it, and a scanning optical microscope. <P>SOLUTION: The spectroscope includes an outgoing end which emits divergent light containing plural wavelengths as a substantial point source, a first optical system for turning the divergent light emitted from the above outgoing end into subparallel light, spectral element for making spectroscopy of the luminous flux turned into subparallel light by the above first optical system, and a second optical system for converging the luminous flux on which spectroscopy is made by the above spectral element in the vicinity of focal plane, comprising first lenses in which the above 1st optical system has negative focal distance and second lenses with positive focal distance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a spectroscope, a confocal optical system using the spectroscope, and a scanning optical microscope.

  Conventionally, as this type of spectroscope, there is one as described in JP-A-11-183249. This configuration is shown in FIG. From FIG. 10, in this spectrometer, the diverging light emitted from the optical fiber is converted into parallel light by the first lens. The parallel light is diffracted by the diffraction grating, and only light having a specific wavelength is guided to the second lens. Then, the light condensed by the second lens is detected through the output slit. In addition, the wavelength of the light to detect can be changed by rotating a diffraction grating (for example, refer patent document 1).

As another conventional technique, there is a spectrum selection device described in JP-A-2002-122787. This configuration is shown in FIG. This spectrum selection device includes means for selecting a predetermined spectrum region, and has a structure in which the spectrally resolved light beam and the detection device can change their relative positions with each other (see, for example, Patent Document 2).
JP 11-183249 A (paragraph number 0021-0028, FIG. 1) JP 2002-122787 A (paragraph number 0006-0028, FIG. 1)

However, the wavelength | Change _{{λ λ 1 <λ <λ} 2} in order to detect at a time, for example, is of the type shown in JP-A-11-183249, an output slit wider width There is a need to. At this time, since there is no guarantee that the converging spot of wavelength λ ₁ condensing at the slit end is good, the converging spot of (λ ₁ −Δλ) may not be sufficiently small. In addition, in this case, there is a problem that the wavelength resolution is not good because a part of the condensed spot of (λ ₁ −Δλ) is located inside the slit and the component passes through the slit. Incidentally, 0 <Derutaramuda«ramuda _1, if the wavelength resolution is poor, FIG 12 (a) the detected light intensity with respect to wavelength when a good, shown in (b).

Further, the type shown in Japanese Patent Application Laid-Open No. 2002-122787 has a configuration in which the light beam is split into parallel light and guided to the detector without being collected, so that the adjacent wavelength components are completely eliminated. Without being separated, it will be detected while being mixed. That is, there is a problem that part of the light of (λ ₁ −Δλ) or (λ ₂ + Δλ) is detected.

  Furthermore, in the spectroscope described in JP-A-11-183249, there is a method for increasing the thickness of the parallel light flux between the first lens and the second lens as a method for increasing the wavelength resolution. . In this method, it is necessary to increase the NA (numerical aperture) of the second lens. For this reason, the spot diameter collected by the second lens is reduced, and as a result, the resolution is increased.

  Here, in order to increase the thickness of the parallel light flux, it is necessary to make the first lens have a long focal length or to increase the NA of the outgoing fiber. However, in the former case, there is a problem that by changing the lens to one having a long focal length, the distance from the output fiber to the lens becomes long and the apparatus becomes large. In the latter case, there is also a problem that the positioning accuracy between the outgoing fiber and the lens becomes severe.

  Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to use a spectroscope capable of configuring the entire apparatus in a compact manner without unnecessarily increasing the placement accuracy of optical elements. It is to provide a confocal optical system and a scanning optical microscope.

In order to solve the above problems, the present invention proposes the following means.
The invention according to claim 1 is an emission end that emits divergent light including a plurality of wavelengths as a point light source, and a first optical system that makes the divergent light emitted from the emission end substantially parallel. The first optical system includes a spectroscopic element that splits a light beam that has been substantially parallel light, and a second optical system that condenses the light beam split by the spectroscopic element in the vicinity of a focal plane. Has proposed a spectroscope comprising a first lens group having a negative focal length and a second lens group having a positive focal length.

According to the present invention, the first optical system is constituted by a first lens group having a negative focal length and a second lens group having a positive focal length, so that a so-called telephoto type is obtained. The distance from the light source to the final lens surface is shorter than the focal length. At this time, since the NA of the light emitted from the point light source is the same, the overall length of the lens system is shortened as compared with other optical systems having the same focal length without changing the positioning accuracy. Therefore, this can make the entire apparatus compact.
Note that the exit end includes a spot condensed by a lens, an opening (slit or pinhole) arranged at the spot position, an end face of an optical fiber, or the like. Alternatively, a so-called substantial point light source in which the area of the opening or the end face of the optical fiber is sufficiently small serves as the emission end.

  According to a second aspect of the present invention, there is provided a light source, an objective lens for condensing the light emitted from the light source on the sample, a spectroscope for spectrally reflecting the reflected light from the sample or the fluorescence generated from the sample, and the spectrum A confocal optical system in which a point optically conjugate with the sample is provided between the sample and the sample, wherein the spectroscope is a spectroscope described in claim 1. ing.

  According to the present invention, since the spectroscope described in claim 1 is used for the photodetecting portion constituting the confocal optical system, the entire apparatus can be made compact. For example, a flow cytometer that analyzes the properties of cells such as the absolute number of cells and the size of particles is given a spectroscopic function by flowing fluorescence-stained cells in a thin water stream and analyzing the fluorescence and scattered light obtained by laser irradiation. A compact device can be realized.

  According to a third aspect of the present invention, there is provided a light source, an objective lens for condensing the light emitted from the light source on the specimen, and the light that is disposed between the light source and the objective lens and is condensed on the specimen. An optical deflector that optically scans a point, and a pupil projection optical system that is disposed between the optical deflector and the objective lens and optically conjugates the optical deflector and the pupil of the objective lens And a confocal pinhole which is disposed at a position optically conjugate with the specimen between the optical deflector and the spectroscope and is substantially a point light source. A scanning optical microscope, which is a spectroscope, has been proposed.

  According to the present invention, since the spectroscope described in claim 1 having excellent wavelength resolution is used as the spectroscope constituting the scanning optical microscope, it is possible to realize a scanning optical microscope whose entire apparatus is compact. .

  According to a fourth aspect of the present invention, there is provided a light source, an objective lens for condensing the light emitted from the light source on the specimen, and the light that is disposed between the light source and the objective lens and is condensed on the specimen. An optical deflector that optically scans a point, and a pupil projection optical system that is disposed between the optical deflector and the objective lens and optically conjugates the optical deflector and the pupil of the objective lens And an entrance end of a single mode fiber disposed at a position optically conjugate with the sample between the optical deflector and the spectroscope, and an exit end of the single mode fiber is a point light source of the spectroscope Then, a scanning optical microscope in which the spectroscope is the spectroscope described in claim 1 is proposed.

  According to the present invention, since it is not necessary to arrange the scanning microscope unit and the spectroscope unit close to each other with such a configuration, the degree of freedom in arrangement is high and the entire apparatus having the spectroscopic function is compactly scanned. Type optical microscope can be realized.

  As described above, according to the present invention, the first optical system in which divergent light from a substantial point light source is substantially parallel light is composed of a lens having a negative focal length and a lens having a positive focal length. Thus, a compact spectroscope can be configured.

Hereinafter, a spectroscope according to an embodiment of the present invention, a confocal optical system using the spectroscope, and a scanning optical microscope will be described in detail with reference to FIGS. 1 to 10 together with reference examples.
As shown in FIG. 1, the spectroscope according to the reference example of the present invention includes a pinhole 1, a first optical system 2, a planar diffraction grating 3, a second optical system 4, a variable width slit 5, and light detection. And a dichroic mirror 7.

  The divergent light transmitted through the pinhole 1 is converted into substantially parallel light by the first optical system 2 and is incident on the planar diffraction grating 3. Note that the diameter of the pinhole in which the light beam transmitted through the pinhole 1 and diverging can be regarded as the light beam substantially emitted from the point light source is determined by the NA and wavelength of the light beam transmitted through the pinhole 1 and diverged. . Numerical data of the first optical system 2 is described in Table 1 (surface numbers 2 and 3) described later. A shape based on the numerical data is shown in FIG.

The planar diffraction grating 3 has a groove formed on the surface thereof, and is configured to be rotatable about an axis substantially parallel to the groove. With this configuration, the wavelength λ ₀ that is parallel to the optical axis of the second optical system 4 can be selected. The light beam having the wavelength λ ₀ diffracted and split by the plane diffraction grating 3 enters the second optical system 4 while being parallel to the optical axis of the second optical system 4. In the second optical system 4, the planar diffraction grating 3 is disposed in the vicinity of the front focal position.

The light beams having the respective wavelengths incident on the second optical system 4 are emitted substantially telecentricly. Then, in the vicinity of the rear focal position of the second optical system 4, the light beams having the respective wavelengths are collected in a plane perpendicular to the optical axis of the second optical system 4. Moreover, the variable width slit 5 is arrange | positioned in the said condensing position, and the photodetector 6 is arrange | positioned in the back. Here, the imaging performance of the second optical system 4 according to the present embodiment is sufficiently good, and particularly the chromatic aberration is corrected well. A specific example is shown in FIG. As shown in FIG. 5, the second optical system 4 is composed of a plurality of (here, two) lenses. Here, it is a cemented lens composed of a negative lens and a positive lens. With such a configuration, the focused spot of each wavelength that can be formed at the slit position is sufficiently small. Therefore, even when Δλ is small, the spots of λ ₁ and (λ ₁ −Δλ) can be separated without overlapping. The numerical data of the second optical system 4 is described in Table 1 (surface numbers 5 to 7) described later.

The slit width of the variable width slit 5 is adjusted so that the λ ₁ spot is transmitted through the slit and the (λ ₁ −Δλ) spot is blocked by the slit. Similarly, the other side, lambda ₂ spots is transmitted, and the position of the slit is determined so as to cut off by a slit spots (λ _{2 +} Δλ). Accordingly, at this time, the wavelengths detected by the photodetector 6 are from λ ₁ to λ ₂ . Thus, the range of wavelengths that can be set can be freely determined by adjusting the rotation angle of the planar diffraction grating 3 and the width of the variable width slit 5.

本参考例においては、ピンホール１を透過し発散する光線のＮＡは０．０１１である。また、第１の光学系の焦点距離が１３５ｍｍであるため、第１の光学系を透過した後、略平行光となった光束の径Ｄは、φ３ｍｍである。さらに、回折面の溝本数は６００本／ｍｍ、第１の光学系の光軸と第２の光学系の光軸のなす角は４０度であり、回折格子の溝方向はこの２本の光軸のどちらとも垂直の関係にある。 In the following, lens data (see Table 1) is shown for the first reference example of the present embodiment.

In this reference example, the NA of the light beam transmitted through and diverging from the pinhole 1 is 0.011. Further, since the focal length of the first optical system is 135 mm, the diameter D of the light beam that has become substantially parallel light after passing through the first optical system is φ3 mm. Further, the number of grooves on the diffraction surface is 600 / mm, the angle formed by the optical axis of the first optical system and the optical axis of the second optical system is 40 degrees, and the groove direction of the diffraction grating is the direction of these two light beams. Both axes are in a vertical relationship.

Under these conditions, the relationship between the rotation angle of the diffraction grating (the incident angle of the light beam on the diffraction surface) and the wavelength λ ₀ parallel to the optical axis of the second optical system is as shown in [Table 2]. Become. Further, the diameter of the spot collected by the second optical system when the wavelength λ ₀ is changed (here, the calculation was performed as the diameter of a region including 90% energy in terms of wave optics), and [Table 3] shows the relationship between the positional deviation amounts of the spots when the wavelength is changed by 1 nm.

FIG. 2 shows a state in which light beams having spots with a wavelength of (λ ₀ −1), λ ₀ , (λ ₀ +1) nm and a diameter of 20 μm are shifted by 18 μm. According to this, the light flux having the wavelength λ ₀ nm and the light flux having the wavelength (λ ₀ +1) nm cannot be separated due to the overlap of the spots, but the light flux having the wavelength (λ ₀ -1) nm and the wavelength (λ ₀ +1) are not separated. ) It can be seen that separation with the beam of nm is possible because there is no overlap of spots. Therefore, it can be seen that the wavelength resolution Δλ in this case is larger than 1 nm and smaller than 2 nm.

In this embodiment, the incident angle α of the light beam incident on the planar diffraction grating 3, the number of gratings N per unit length of the planar diffraction grating 3, the diffraction order m, and the diameter of the light beam after passing through the first optical system. If D is α = 9 °, N = 600 lines / mm, m = 1, D = 3 mm, and this is substituted into the following [Equation 1], it can be seen that the present embodiment satisfies this condition.

ここで、Δλは波長λの光と波長（λ−Δλ）の光を分離できる波長分解能を、βは反射型平面回折格子に入射する光束の出射角を、Ｎは反射型平面回折格子の単位長さあたりの格子本数を、ｍは回折次数を、ｆは第２の光学系の焦点距離を示す。 In the above description, it is assumed that there is no chromatic aberration in the optical system. However, in general, aberration occurs. Therefore, in consideration of this, the diameter of the condensing spot having the wavelength λ ₁ that can be formed at the slit position after passing through the second optical system (here, the diameter of the region including 90% energy in terms of wave optics) .) Is d ₁ , the wavelength of λ ₁ and (λ ₁ −Δλ) can be separated if the following [Equation 2] is satisfied.

Here, Δλ is a wavelength resolution capable of separating light of wavelength λ and light of wavelength (λ−Δλ), β is an emission angle of a light beam incident on the reflective planar diffraction grating, and N is a unit of the reflective planar diffraction grating. The number of gratings per length, m is the diffraction order, and f is the focal length of the second optical system.

If the wavelength resolution Δλ is determined first and the second optical system satisfying the above [Equation 2] is configured, a spectrometer having the wavelength resolution Δλ can be realized. Moreover, when the focused spot diameter of the wavelength lambda ₂ and d _2, can be separated by replacing the d ₁ [Expression 2] to d _2, light of the wavelength lambda ₂ of the light (λ _{2 +} Δλ) . It should be noted that the cemented lens of the 5-6th surface in [Table 1] constituting the second optical system satisfies the following [Equation 3] relationship.

Next, examples according to the embodiment of the present invention will be described. In the first reference example, the spectrometer according to this example is configured by replacing the first optical system (surface numbers 2 to 3 in [Table 1]) with the following lenses in [Table 4]. That is, as shown in FIG. 6, in this embodiment, the first optical system is composed of a first lens group having a negative focal length and a second lens group having a positive focal length. It is a so-called telephoto type, and the distance from the point light source to the final lens surface is shorter than the focal length. Therefore, according to the present embodiment, in the first reference example, the distance from the pinhole 1 to the final surface of the first optical system is 136.1 mm, and the focal length and optical imaging performance are almost the same. It can be shortened by 60 mm or more without changing.

Next, a second reference example will be described with reference to FIG.
The laser scanning microscope according to the second reference example includes a light source 501, a beam expander 502, a beam splitter 503, optical deflectors 504 and 505, a pupil transmission optical system 506, a pupil projection optical system 507, and an objective lens. 508, a specimen 509, a confocal lens 514, a confocal pinhole 515, and a spectroscope (the spectroscope shown in the first embodiment) 516.

  The light beam emitted from the laser light source 501 becomes a light beam having an appropriate diameter by the beam expander 502 and is deflected by the optical deflector 504. The deflected light beam passes through the pupil transmission optical system 506, the second optical deflector 505, the pupil projection optical system 507, and the objective lens 508, and is scanned on the sample 509 to excite the sample 509. Fluorescence emitted from the specimen 509 travels in the optical system in the opposite direction, is descanned, and enters the beam splitter 503.

  The fluorescent component deflected by the beam splitter 503 enters the confocal lens 514, is condensed, and passes through the pinhole 1 in the spectroscope 516. The fluorescence passing through the pinhole 1 is used as a point light source in the spectroscope 516. In this reference example, since the spectroscope described in the first reference example is used as the spectroscope, a laser scanning microscope having a spectroscopic function can be configured thereby.

Next, a third reference example will be described with reference to FIG.
The laser scanning microscope according to the third reference example is an example in which a sample 510 for a flow cytometer is used as a sample.
The light beam emitted from the laser light source 501 becomes a light beam having an appropriate diameter by the beam expander 502, is condensed by the objective lens 508, and is irradiated onto the sample 510. In the specimen 510, cell components such as cells or chromosomes are suspended in a liquid and passed through the fluid system at high speed.

  Fluorescence emitted from the sample 510 by being excited by the laser light travels in the opposite direction to the previous optical system and enters the beam splitter 503. The fluorescent component incident on the beam splitter 503 is deflected, incident on the confocal lens 514, collected, and passes through the pinhole 1 in the spectrometer 516. The fluorescence passing through the pinhole 1 is used as a point light source in the spectroscope 516. In this reference example, the spectroscope described in the first reference example is used as the spectroscope, and thus a flow cytometer having a spectroscopic function can be configured.

Next, a fourth reference example will be described with reference to FIG.
The laser scanning microscope according to the fourth reference example has a configuration in which a single mode fiber 517 is provided between the confocal lens 514 and the spectroscope 516 as compared with the second reference example. Therefore, the optical action is the same as that of the third embodiment until the light beam reaches the confocal lens 514. The light condensed by the confocal lens 514 enters from the incident end of the single mode fiber, and the light emitted from the exit end functions as a point light source of the spectrometer 516.

  In this reference example, since the single mode fiber 517 is provided, if the incident end is disposed at the condensing position of the confocal lens 514 and the output end is disposed at the position of the point light source of the spectroscope 516, the single mode fiber 517 is provided. By changing the length, the positional relationship between the laser scanning microscope and the spectroscope can be freely selected, so that a laser scanning microscope having a degree of freedom in arrangement and having a spectroscopic function can be configured. .

Next, a fifth reference example will be described with reference to FIG.
The fifth reference example shows a two-channel spectrometer. This spectroscope has one of the beam splitter, polarization beam splitter, dichroic mirror 7 or the like disposed between the first optical system 2 and the plane diffraction grating 3 shown in FIG. It is configured by dividing. The tip of the divided optical path, that is, the configuration from the planar diffraction grating 3 to the photodetector 6 is the same as in FIG. With such a configuration, a two-channel spectrometer can be realized. The spectroscope of this reference example can be configured by replacing the spectroscope of the second reference example to the fourth reference example.

The embodiments of the present invention have been described in detail with reference examples with reference to the drawings. However, the specific configuration is not limited to these embodiments, and the design is within the scope not departing from the gist of the present invention. Changes are also included. For example, the laser scanning microscope and the confocal optical system in which the spectroscope in the laser scanning microscope and the confocal optical system of the second reference example to the fourth reference example are replaced with the spectroscope according to the present embodiment may be configured. it can.
Further, for example, in the first reference example, it has been described that the diameter of the pinhole is determined by the NA of the light beam and the wavelength of the light beam. However, in consideration of each component constituting the optical system, the flexibility in the pinhole diameter is increased. You may use a variable diameter pinhole so that it may have.

  Further, in the first reference example and [Table 1], the second optical system has been described as a cemented lens. However, as long as the requirement of [Equation 3] is satisfied, the first optical system includes two or more lenses separated from each other. May be. In the third reference example, the light source of the spectroscope has been described as being a pinhole, but may not be a pinhole.

It is a block diagram of the spectrometer concerning the reference example of this invention. It is the schematic diagram showing a mode that the spot of a different wavelength was located in a line, shifting a position. It is a block diagram of the laser scanning microscope which has a spectral function concerning the 2nd reference example of this invention. It is sectional drawing of the 1st optical system concerning the 1st reference example of this invention. It is sectional drawing of the 2nd optical system concerning the 1st reference example of this invention. It is sectional drawing of the 1st optical system concerning the Example of this invention. It is a block diagram of the flow cytometer which has a spectroscopy function concerning the 3rd reference example of this invention. It is a block diagram of the laser scanning microscope which has a spectroscopy function concerning the 4th reference example of this invention. It is a block diagram of the spectrometer concerning the 5th reference example of this invention. It is a block diagram of the spectrometer concerning a prior art example. It is a block diagram of the spectrum selection apparatus concerning a prior art example. It is a figure which shows the light quantity in a state with bad wavelength resolution, and a favorable state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pinhole, 2 ... 1st optical system, 3 ... Planar diffraction grating, 4 ... 2nd optical system, 5 ... Variable width slit, 6 ... Photodetector , 7 ... Dichroic mirror, 501 ... Light source, 502 ... Beam expander, 503 ... Beam splitter, 504, 505 ... Optical deflector, 506 ... Pupil transmission optical system, 507 ..Pupil projection optical system, 508... Objective lens, 509... Sample, 510... Sample for flow cytometer, 514... Confocal lens, 515. ..Spectroscope, 517 ... Single mode fiber,

Claims (4)

  An exit end that emits divergent light including a plurality of wavelengths as a point light source, a first optical system that makes the divergent light emitted from the exit end substantially parallel, and the first optical system A spectroscopic element that splits the light beam that has become substantially parallel light; and a second optical system that condenses the light beam split by the spectroscopic element in the vicinity of the focal plane, wherein the first optical system has a negative focal length. A spectroscope composed of a first lens group having a second lens group having a positive focal length.   A light source, an objective lens for condensing the light emitted from the light source on the sample, a spectroscope for spectroscopic analysis of reflected light from the sample or fluorescence generated from the sample, and between the spectroscope and the sample A confocal optical system provided with a point optically conjugate with the specimen, wherein the spectroscope is the spectroscope described in claim 1.   A light source, an objective lens for condensing the light emitted from the light source on the specimen, and light that is disposed between the light source and the objective lens and optically scans the light spot collected on the specimen A deflector, a pupil projection optical system disposed between the optical deflector and the objective lens, wherein the optical deflector and the pupil of the objective lens are optically conjugate with each other; and the optical deflector and the spectroscope And a confocal pinhole, which is substantially a point light source, disposed at a position optically conjugate with the sample with respect to the spectroscope, and the spectroscope is the spectroscope according to claim 1. Optical microscope.   A light source, an objective lens for condensing the light emitted from the light source on the specimen, and light that is disposed between the light source and the objective lens and optically scans the light spot collected on the specimen A deflector, a pupil projection optical system disposed between the optical deflector and the objective lens, wherein the optical deflector and the pupil of the objective lens are optically conjugate with each other; and the optical deflector and the spectroscope An entrance end of a single mode fiber disposed at a position optically conjugate with the sample with respect to the spectroscope, and an exit end of the single mode fiber is a point light source of the spectroscope, A scanning optical microscope, which is the spectroscope according to claim 1.

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