JP5787151B2 - Spectroscopic unit and scanning microscope - Google Patents

Description

  The present invention relates to a spectroscopic unit and a scanning microscope.

  A spectroscopic unit that spectrally detects signal light detected by a scanning microscope is generally configured to split the light with a spectroscopic element such as a diffraction grating and detect the spectroscopic light with a light receiver such as a line detector. (For example, refer to Patent Document 1). Such a spectroscopic unit disperses the signal light, so that the amount of light at the time of detection becomes very weak. In addition, in order to improve the wavelength resolution, the light from the incident light source is generally limited by a slit, a pinhole, or the like, so that the amount of detected light is further darkened.

JP 2006-153763 A

  However, when using PMTs (photomultiplier tubes) arranged in a line as a line detector in such a spectroscopic unit, it is necessary to increase the length of the line detector in order to improve the wavelength resolution. There was a problem that the unit would become larger.

  The present invention has been made in view of such problems, and an object thereof is to provide a compact spectroscopic unit having a high wavelength resolution and a scanning microscope having the spectroscopic unit.

In order to solve the above problems, a spectroscopic unit according to the present invention includes a collimator optical system that converts light into a substantially parallel light beam, an optical path dividing unit that divides the substantially parallel light beam into a plurality of light beams, and at least one of the plurality of light beams. A spectroscopic element that splits the light, a rotary table on which a plurality of the spectroscopic elements having different spectral characteristics are arranged, and a light receiver that receives the spectroscopic light dispersed by the spectroscopic element. possess a photodetector plurality of light receiving elements are arranged two-dimensionally in a direction perpendicular to the wavelength dispersion direction, and a focusing optical system for focusing the light receiving element surface of the light receiver spectroscopic light from the spectral element A plurality of rotation tables are arranged in a direction orthogonal to the wavelength dispersion direction, and by rotating each of the plurality of rotation tables, at least one of a plurality of light beams is incident on each spectroscopic element arranged on each rotation table. Movably configured location, at least two of the plurality of light beams, characterized in that respectively incident on different placed on the rotary table the said spectral element.

In such a spectroscopic unit, it is preferable that at least two of the plurality of spectroscopic elements on which the plurality of light beams are incident have different wavelength resolutions.

Further, in such a spectroscopic unit, each of the plurality of rotary table is preferably made incident angle of the light beam incident on the spectral element arranged on the rotary table is capable of changing configurations respectively.

  In such a spectroscopic unit, the optical path splitting unit preferably includes a dichroic mirror, and the dichroic mirror is preferably split into light fluxes of at least two different wavelength bands.

  Further, in such a spectroscopic unit, the optical path splitting unit preferably includes a half mirror, and the half mirror is preferably split into at least two light beams having the same wavelength band.

  In such a spectroscopic unit, the light receiving element of the light receiver is preferably a PMT.

  In such a spectroscopic unit, the light receiving element of the light receiver is preferably a CCD.

  In such a spectroscopic unit, the spectroscopic element is preferably a diffraction grating.

  In such a spectroscopic unit, the spectroscopic element is preferably a prism.

  Further, the scanning microscope according to the present invention scans light from a light source, condenses it on a specimen by an objective lens, and collects light emitted from the specimen by an objective lens, and light from the microscope. Any of the above-described spectroscopic units that detect and detect light.

  When the present invention is configured as described above, a compact spectroscopic unit having a high wavelength resolution and a scanning microscope having the spectroscopic unit can be provided.

It is a block diagram which shows an example of a structure of a spectroscopy system. It is explanatory drawing for demonstrating the spectroscopy unit which concerns on 1st Embodiment, (a) shows the top view of this spectroscopy unit, (b) shows the perspective view of a light receiver. It is explanatory drawing for demonstrating the state of the signal light beam which injects into a diffraction grating in 1st Embodiment, (a) shows a top view, (b) shows a side view. It is explanatory drawing for demonstrating the state of the signal light beam which injects into a diffraction grating in the modification of 1st Embodiment, (a) shows a top view, (b) shows a side view. It is explanatory drawing for demonstrating the state of the signal light beam which injects into a diffraction grating in 2nd Embodiment, (a) shows a top view, (b) shows a side view. It is a graph which shows the emission spectrum of GFP (green fluorescent protein), Comprising: (a) shows the case where the wavelength band of 400-700 nm is acquired with a 10 nm pitch, (b) shows the wavelength band of 490-550 nm with a 2 nm pitch. Indicates the acquired case.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, the configuration of a spectroscopic system, which is an example of a scanning microscope with a spectroscopic function, will be described with reference to FIG. The spectroscopic system 1 includes a confocal microscope having a light source system 10, a confocal unit 20, and a microscope 30, a spectroscopic unit 40, and an information processing device 50. In the spectroscopic system 1, the confocal unit 20 and the spectroscopic unit 40 are optically connected by an optical fiber 28 via fiber couplers 29a and 29b.

  The light source system 10 includes a laser device 11, an optical fiber 13, and fiber couplers 12 and 14. The laser device 11 includes, for example, a laser diode, and emits illumination light having a target wavelength characteristic. This illumination light is guided to the confocal unit 20 via the optical fiber 13. In the example of FIG. 1, excitation light for exciting the specimen 33 to emit fluorescence is emitted as illumination light.

  The confocal unit 20 includes a collimating lens 21 that converts illumination light from the light source system 10 into a substantially parallel light beam, a dichroic mirror 22, a scanning unit 23, a scanner lens 24, a condensing lens 25, and a pinhole 26a. A pinhole plate 26 and a relay lens 27 are provided. The microscope 30 includes an objective lens 32 and a second objective lens 31, and a stage 34 on which the sample 33 is placed. The confocal unit 20 and the microscope 30 are combined to form a scanning confocal microscope. The dichroic mirror 22 is configured to reflect the laser light emitted from the light source system 10 toward the microscope 30 and transmit the fluorescence emitted from the specimen 33 excited by the laser light. Further, the image side focal point of the condenser lens 25 is disposed so as to substantially coincide with the pinhole 26 a of the pinhole plate 26.

  The spectroscopic unit 40 includes a collimating optical system 41 that uses signal light (fluorescence in the example of FIG. 1) incident from the optical fiber 28 as a substantially parallel light beam, and diffraction gratings 431 and 432 that are three types of spectroscopic elements having different spectral characteristics. , 433 (collectively referred to as a diffraction grating 43), a rotary table 42 that holds and rotates them, a plurality of light receiving elements 45a arranged in an array to form a line detector, and a diffraction grating 43 A condensing optical system 44 that forms an image of the diffracted light (spectral light) emitted from (any of the diffraction gratings 431 to 433) on the light receiving surface of the light receiver 45 and a power source for driving the light receiver 45 are supplied. A high voltage power supply 46 and a detection circuit 47 that amplifies and digitizes the output of each light receiving element 45a of the light receiver 45 and outputs it as detection data. It should be noted that the preceding optical system (collimating optical system 41 or condensing optical system) is set so that the NA of the signal light (spectral light) incident on the light receiving element 45a is within the range of the effective NA or the optimum NA of the light receiving element 45a. 44) is formed.

  The information processing device 50 includes a frame memory 51 that stores detection data output from the detection circuit 47, a central processing unit (CPU) 52 that calculates target spectral characteristics based on the stored detection data, and a display device. 53, an external storage device 54, an input device 55, and a scanner driving device 56. Here, although not shown, the CPU 52 includes a calculation unit and a main storage unit. For example, a liquid crystal display device is used as the display device 53. As the external storage device 54, for example, a hard disk device, an optical recording medium storage device, a semiconductor storage device, or the like is used. The input device 55 includes devices such as a keyboard and a mouse, for example.

  The external storage device 54 stores an operation program for the CPU 52 and various data. Specifically, it has a function as a storage means for storing spectral characteristics (spectral data) for each of a plurality of optical elements in correspondence with each optical element. Such a program and preliminarily given data are stored in the external storage device 54 by, for example, reading and installing from a storage medium such as a CD-ROM using a reading device (not shown).

  The CPU 52 loads a program stored in the external storage device 54 and performs various controls, arithmetic processing, and the like. The program stored in the external storage device 54 includes means for controlling the operation of the scanning unit 23 via the scanner driving device 56, and means for calculating spectral characteristics based on data obtained from the measurement target. The spectral characteristic information about the optical element to be used, which is stored by the storage unit based on the information for identifying the received optical element, is read out, and the spectral characteristic information of the optical system to be used is obtained. And a program for operating the CPU 52 by means for obtaining the spectral characteristics of the object using the spectral data output from the spectral unit 40 described above. In addition to the storage device, a program for operating the CPU 52 as storage means for storing the spectral characteristics of each of the plurality of optical elements in correspondence with each element is also included.

  The spectroscopic unit 40 will be described in more detail. The spectroscopic unit 40 takes in the signal light through the optical fiber 28, splits it with any of the diffraction gratings 431 to 433, and receives the spectroscopic light at each light receiving element 45 a of the light receiver 45.

  As shown in FIG. 1, the optical fiber 28 is attached to the spectroscopic unit 40 with a fiber coupler 29b. The signal light from the optical fiber 28 is all collimated by the collimating optical system 41 and is incident on the diffraction grating 43 selected from the diffraction gratings 431 to 433. The signal light incident on the diffraction grating 43 is diffracted in the direction of the diffraction angle determined by the wavelength and is split. The split signal light is condensed by the condensing optical system 44, imaged on the light receiving surface of the light receiver 45, and incident on the light receiver 45. From the light receiver 45, an electrical signal corresponding to the amount of signal light incident on each light receiving element 45a is output and processed by the information processing device 50, whereby a spectral signal of wavelength versus intensity can be obtained.

  The diffraction gratings 431 to 433 differ in the number of engraved lines (the number of diffraction grating grooves per 1 mm). Further, these diffraction gratings 431 to 433 are installed on the rotary table 42 at different angular positions. Therefore, the wavelength band detected by the light receiver 45 can be changed by turning the rotary table 42 and changing the angle of incidence on the diffraction gratings 431 to 433. In addition, the wavelength resolution can be changed by switching from one diffraction grating to another among the diffraction gratings 431 to 433.

  The optical fiber 28 is a step index type made of a quartz core, and has a core diameter of 50 μm and an NA of 0.22. Light emitted from the optical fiber 28 via the fiber coupler 29 b is guided into the spectroscopic unit 40. In this embodiment, the light is guided to the dispersion optical system via the collimating optical system 41. At this time, the spectral system 1 according to the present embodiment handles a weak optical signal (fluorescence). For this reason, in order to obtain a high SN ratio, it is necessary to use the signal light beam introduced by the optical fiber 28 with high efficiency. Therefore, the role of the collimating optical system 41 is to take in the signal light beam (diverged light) introduced by the optical fiber 28 without loss and to guide it to the diffraction grating 43 which is a subsequent spectroscopic element.

  The light receiver 45 is composed of, for example, a 32-channel multi-anode line PMT (photomultiplier tube). This PMT has a structure in which the element size of one channel is about 0.8 mm × 7 mm, and 32 channels are arranged at a pitch P (= 1 mm) in the wavelength dispersion direction (the direction in which signal light is dispersed). ing.

  As the condensing optical system 44, a condensing lens can be used, and a condensing mirror can also be used. FIG. 1 shows a case where a condensing lens is used as the condensing optical system 44. If the size of the signal light image (image of the core of the optical fiber) from the optical fiber 28 on the light receiving surface of the light receiver 45 is smaller than the size of the light receiving element 45a of the light receiver 45 in the wavelength dispersion direction or the pitch P. A high wavelength resolution corresponding to the number of elements of the light receiver 45 can be obtained. Furthermore, in consideration of the aberration of the optical system, it is desirable that the size of the signal light image is smaller than this. The condensing optical system 44 is configured such that an image of the light emitted from the diffraction grating on the light receiver 45 is formed with a diameter smaller than the pitch P described above.

  Next, the operation of the spectroscopic system 1 will be described. In this example, the specimen 33 to be observed is irradiated with laser light, and the fluorescence excited in the specimen 33 is captured by the microscope 30 and guided to the spectroscopic unit 40 to obtain spectroscopic data. The procedure of measurement or observation is roughly as follows.

  Laser light (excitation light) emitted from the laser device 11 of the light source system 10 that is a light source is introduced into the optical fiber 13 through the fiber coupler 12. Further, the laser light passing through the optical fiber 13 enters the collimating lens 21 of the confocal unit 20 from the fiber coupler 14. The laser light is converted into substantially parallel light by the collimating lens 21, then reflected by the dichroic mirror 22 to the optical path on the microscope 30 side, and introduced into the scanning unit 23 and the scanner lens 24, which are composed of two orthogonally arranged galvanometers. And scanned two-dimensionally. The scanned laser light passes through the second objective lens 31, is condensed by the objective lens 32, and is condensed at one point on the sample 33. The position on the specimen 33 scanned two-dimensionally by the scanning unit 23 is controlled by controlling the operation of the galvanometer in the scanning unit 23 by the central processing unit 52 via the scanner driving device 56 of the information processing apparatus 50. Is done. Then, the fluorescence (signal light) emitted from the specimen 33 excited by the laser light is converted into substantially parallel light by the objective lens 32, and follows the path opposite to the laser light (excitation light) to the dichroic mirror 22. Incident. The fluorescence that has entered the dichroic mirror 22 passes through the dichroic mirror 22 and is collected by the condenser lens 25 onto the pinhole 26 a of the pinhole plate 26.

  The light that has passed through the pinhole 26a is guided to the optical fiber 28 from the fiber coupler 29a through the relay lens 27. Through the relay lens 27, as shown in FIG. 1, the light that has passed through the pinhole 26a becomes a divergent light beam as it is, and is condensed again, and apparently appears at the opening end of the optical fiber 28. Even with a small aperture diameter, it becomes possible to enter effectively (with little loss).

  Here, since the condensing point formed in the pinhole 26a is an image of a light spot on the specimen 33, even if there is light emitted from another point on the specimen 33, the pinhole 26a. Then, an image is not formed and is blocked by the pinhole plate 26 and hardly reaches the fiber coupler 29a. Therefore, only the light that can pass through the pinhole 26 a can reach the fiber coupler 29 a via the relay lens 27. As a result, the scanning confocal microscope is a microscope capable of observing a specimen not only with high lateral resolution but also with high vertical resolution.

  The fluorescence incident on the fiber coupler 29a passes through the optical fiber 28 and is introduced into the spectroscopic unit 40 via the fiber coupler 29b. The fluorescence introduced into the spectroscopic unit 40 becomes a substantially parallel light beam in the collimating optical system 41 and is introduced into any of the diffraction gratings 431 to 433. In the spectroscopic system 1 according to the present embodiment, as described above, three types of these diffraction gratings 431 to 433 are prepared to make the wavelength resolution variable, and the rotation table 42 is rotated by being controlled by a pulse motor (not shown). Accordingly, any one of the diffraction gratings 43 is selected and used.

  The fluorescence diffracted by the diffraction grating 43 is collected by the condensing optical system 44 and is incident on the light receiver 45 at a spread angle corresponding to the wavelength resolution of the diffraction grating 43. The incident fluorescence is converted into an electric signal by the photoelectric effect of the light receiving element 45a. The converted electric signal is amplified by the amplifier 47a, converted into a digital signal by the A / D converter 47b, sent to the frame memory 51, calculated and processed by the CPU 52, and displayed on the display device 53 as an image.

  Now, the wavelength resolution in the spectroscopic system 1 having such a configuration will be described. Here, the optical fiber 28 has a core diameter φ of 0.05 mm and NA of 0.2, the collimating optical system 41 has a focal length of 30 mm, and the condensing optical system 44 has a focal length of 300 mm. It is assumed that the light receivers 45 are 32-channel multi-anode type lines PMT arranged at a pitch of 1 mm. That is, the magnification in the spectroscopic unit 40 is 10 times the ratio of the focal lengths of the collimating optical system 41 and the condensing optical system 44, and a fiber image having a diameter of 0.5 mm is formed at the condensing position of the light receiver 45. become.

  Here, the spectrum by the diffraction grating 43 has the relationship of the following conditional expression (1).

sin α + sin β = Nmλ (1)
Where α: angle of incidence on the diffraction grating [°] (angle between the normal of the diffraction grating and the fluorescence)
β: exit angle from the diffraction grating [°] (angle formed between the normal line of the diffraction grating and the m-th order diffracted light)
m: Diffraction order N: Number of engraved lines per 1 mm (number of diffraction grating grooves)
λ: wavelength of incident light [nm]

  From this conditional expression (1), for example, the incident angle of the fluorescence to the diffraction grating 43 is 0 °, and the number N of engraving lines per 1 mm of the diffraction grating 43 is 700. When the light receiver 45 receives light of m = 1), the light of λ = 400 nm which is the lower limit of the wavelength to be dispersed is diffracted at 16.2 °, and the light of λ = 750 nm which is the upper limit is diffracted at 31.7 °. The In the optical system under the above conditions, when the angle at which 400 nm light is diffracted is considered as the optical axis, the light of 750 nm is imaged at a position shifted by 45 mm (300 mm × tan 15.5 = 45 mm). Since the PMT has only 32 (channel) light receiving elements at a pitch of 1 mm, it cannot receive light of all wavelengths from 400 nm to 750 nm. If it is going to receive the light of all the wavelengths, the light receiver 45 which has a 45 mm full length will be needed, and the spectroscopy system 1 (spectral unit 40) will enlarge. By rotating the rotary table 42 described above, the angle of the diffraction grating 43 is changed, and the position of the diffracted light incident on the light receiver 45 is changed to divide the light of 400 nm to 750 nm into several parts, thereby allowing spectroscopic analysis. Although a method of acquiring data is possible, only images that are shifted in time can be acquired, and accurate data cannot be acquired when the fluorescence state of the specimen 33 changes in a short time. is there.

  Further, in order to avoid an increase in the size of the spectroscopic system 1 (spectral unit 40), if the number N of engraving lines per 1 mm of the diffraction grating is reduced, the wavelength incident on each light receiving element 45a of the light receiver 45 increases. Fine wavelength irregularities cannot be detected, resulting in poor wavelength resolution. Specifically, in the above optical system, the wavelength resolution when the number N of engraved lines per 1 mm is 700 is 4.3 nm per channel, and light of all wavelengths is incident on the entire length of the light receiver 45. However, if the number N is 300, the entire length of the light receiver 45 can be accommodated. However, in this case, the wavelength resolution per channel is about 10 nm. Even if the projection magnification of the fiber image of the optical fiber 28 onto the light receiver 45 is lowered, the spectroscopic system 1 (the spectroscopic unit 40) can be made compact, but the wavelength resolution is also deteriorated. When the projection magnification is increased, the fiber image exceeds the width of the light receiving element 45a per channel of the light receiver 45, and therefore the size of the fiber image deteriorates the wavelength resolution.

  Therefore, in order to increase the wavelength resolution while avoiding an increase in the size of the spectroscopic system 1 (the spectroscopic unit 40), a configuration in which the light receiving elements 45a of the light receiver 45 are two-dimensionally arranged to receive the dispersed light will be described. .

[First Embodiment]
First, the configuration of the spectroscopic unit 140 according to the first embodiment will be described with reference to FIGS. 2 and 3. The spectroscopic unit 140 according to the first embodiment is used in a configuration in which the spectroscopic unit 40 is replaced with the spectroscopic unit 140 in the spectroscopic system 1 shown in FIG. For this reason, the configurations of the light source system 10, the confocal microscope having the confocal unit 20 and the microscope 30, and the information processing apparatus 50 are not described in detail by using the same reference numerals.

  The spectroscopic unit 140 according to the first embodiment includes a collimating optical system 141 that converts fluorescence (signal light) emitted from the fiber coupler 29b through the optical fiber 28 into a substantially parallel light beam, and three light paths for the substantially parallel light beam. Diffracting gratings 1431, 1432, and 1433 (collectively referred to as diffraction grating 143), which are three spectroscopic elements that are attached to the rotary table 142 and have different spectral characteristics, and a diffraction grating A condensing optical system 144 composed of a reflective concave mirror that condenses the light diffracted by any of 1431 to 1433, and a light receiver 145 that detects the diffracted light collected by the condensing optical system 144. Is done.

  In the spectroscopic unit 140 according to the first embodiment, the light receiver 145 is configured to display a light receiving region including a plurality of light receiving elements arranged in the horizontal direction (horizontal direction (wavelength dispersion direction)) of the paper surface of FIG. These light receiving elements are arranged in a two-dimensional manner by overlapping three stages in the direction perpendicular to the paper surface of 2 (a) and in the vertical direction of the paper surface of FIG. 2 (b). In the following description, the upper light receiving region is referred to as a first light receiving unit 145a, the middle light receiving region is referred to as a second light receiving unit 145b, and the lower light receiving region is referred to as a third light receiving unit 145c. Each of the first to third light receiving portions 145a to 145c is configured by, for example, the above-described 32-channel multi-anode line PMT.

  In addition, the first light receiving unit 145a, the second light receiving unit 145b, and the third light receiving unit 145c are not limited to the example in which the first light receiving unit 145a, the second light receiving unit 145c, and the three vertical stacks in FIG. A predetermined interval may be provided in the vertical direction.

  The light receiver 145 has a light receiving region composed of a plurality of light receiving elements arranged in the horizontal direction (horizontal direction (wavelength dispersion direction)) in FIG. 2A as a direction orthogonal to the paper surface in FIG. It is not limited to the example in which three stages are stacked in the vertical direction on the paper surface of FIG. 2B, but each of the plurality of light receiving elements is simply arranged in the horizontal direction of the paper surface of FIG. 2A and the direction orthogonal to the paper surface of FIG. By arranging the light receiving elements, the light receiving elements may be arranged two-dimensionally.

  In addition, the optical path splitting unit 148 reflects light in a predetermined wavelength band (for example, 640 to 750 nm) out of light (light having a wavelength of 400 to 750 nm) included in the substantially parallel light beam emitted from the collimating optical system 141. The first dichroic mirror 148a that transmits light of other wavelengths and the light in a predetermined wavelength band (for example, 400 to 520 nm) out of the light included in the substantially parallel light beam that has transmitted through the first dichroic mirror 148a. A second dichroic mirror 148b that reflects light and transmits light of other wavelengths, and a substantially parallel light beam reflected by the first dichroic mirror 148a, reflects one of the diffraction gratings 1431 to 1433 (diffraction). The first mirror 148c irradiated on the grating 143) and the substantially parallel light reflected by the second dichroic mirror 148b And is configured with a, a second mirror 148d for irradiating the diffraction grating 143 reflects.

  The light emitted from the collimating optical system 141 and transmitted through the first and second dichroic mirrors 148a and 148b is incident on the diffraction grating 143 perpendicularly (at an angle of 0 °). 148a is arranged so as to reflect light in the above-mentioned wavelength band below the collimating optical system 141 side, and the first mirror 148c is substantially parallel to the light transmitted through the first dichroic mirror 148a. Reflected (FIG. 3B), and this light is perpendicular to the diffraction grating 143 in the direction of the grooves of the diffraction grating (the direction perpendicular to the paper surface of FIG. 3A) (the pitch direction of the grooves). ) In the plane of FIG. 3A (in the plane of FIG. 3A) so as to be incident at an angle of + 5 ° (FIG. 3A). The second dichroic mirror 148b is disposed so as to reflect the light in the above-mentioned wavelength band upward on the collimating optical system 141 side, and the second mirror 148d transmits the light to the first and second dichroic mirrors 148a, Reflected so as to be substantially parallel to the light transmitted through 148b (FIG. 3B), and this light is perpendicular to the diffraction grating 143 in the direction of the groove of the diffraction grating (FIG. 3A). In the direction (groove pitch direction) perpendicular to the direction (in the direction of the groove) (in the plane of the paper in FIG. 3A) is arranged so as to enter at an angle of −5 ° (FIG. 3A). At this time, as shown in FIG. 3A, the three optical paths have their respective optical paths when viewed from the direction of the groove of the diffraction grating 143 (direction orthogonal to the paper surface of FIG. 3A). Are configured so that their centers substantially coincide with each other on the diffraction plane. Then, according to the conditional expression (1), the center of the light (spectral light) diffracted by the diffraction grating 143 is in the direction of the groove of the diffraction grating with respect to the normal line of the diffraction grating 143 (FIG. 3A). If the direction is 24 ° in the plane (in the plane of the groove in FIG. 3A) perpendicular to the direction of the sheet (the direction perpendicular to the sheet of FIG. 3A) (in the sheet of FIG. 3A), each of the three optical paths divided into the three optical paths. The light in the wavelength band falls within the respective light receiving regions of the first to third light receiving portions 145a to 145c arranged in the direction orthogonal to the paper surface of FIG. 2A and the vertical direction of the paper surface of FIG. The three lines PMT arranged can receive light without waste.

  In the configuration of the spectroscopic unit 140 according to the first embodiment, as shown in FIG. 3B, the three optical paths divided by the optical path dividing unit 148 are the directions of the grooves of the diffraction grating of the diffraction grating 143. The condensing optical system 144 is incident on the diffraction grating 143 as an optical path substantially parallel to a direction orthogonal to (the vertical direction of the paper surface in FIG. 3B) (the horizontal direction of the paper surface in FIG. 3B). Three reflecting concave mirrors arranged in the vertical direction corresponding to each of the three optical paths are required. However, as shown in FIG. 4B, when the light beam is branched by the optical path splitting unit 148, it is incident on the diffraction grating 143 with an angle in the slit direction, that is, the diffraction grating groove of the diffraction grating 143. Is given a predetermined angle with respect to the normal along the direction (angle γ shown in FIG. 4B), the direction of the groove of the diffraction grating (direction perpendicular to the paper surface of FIG. 4A) and diffraction When viewed from the direction perpendicular to the direction of the groove of the grating (the direction perpendicular to the paper surface of FIG. 4B), if the light beams are incident so that the centers of the three optical paths substantially coincide with each other on the diffraction surface, The optical optical system 144 can be realized by a single reflecting concave mirror. In this case, when the slit direction angle is γ [°], it should be noted that the spectrum by the diffraction grating 143 has the relationship of the following conditional expression (2).

(Sin α + sin β) sin γ = Nmλ (2)

  As described above, in the spectroscopic unit 140 according to the first embodiment, the light receiving region of the light receiver 145 is two-dimensionally arranged, and the light path dividing unit 148 has different wavelength bands before entering the diffraction grating 143. Dividing into two optical paths, changing the height direction position and the angle in the plane direction for each wavelength band and making it incident on one diffraction grating 143, and receiving light of each wavelength band arranged two-dimensionally Therefore, the spectroscopic system 1 can be configured which can simultaneously acquire spectroscopic data with a compact and high wavelength resolution. That is, by using the spectroscopic unit 140 according to the first embodiment, the width of the light receiver 145 in the wavelength dispersion direction (the width in the direction in which the light receiving elements are arranged in a line) is substantially the same as that of the conventional spectroscopic unit. Spectral data in the triple wavelength region can be acquired simultaneously with the same wavelength resolution as before. Alternatively, spectral data having a wavelength resolution three times that of the conventional wavelength region can be acquired simultaneously.

[Second Embodiment]
Next, the configuration of the spectroscopic unit 240 according to the second embodiment will be described with reference to FIG. The spectroscopic unit 240 according to the second embodiment includes the rotation table 142 and the diffraction grating 143 of the spectroscopic unit 140 according to the first embodiment shown in FIGS. 2 and 3, and the spectroscopic unit according to the second embodiment. The unit 240 is used by replacing the rotary table 242 and the diffraction grating 243 with each other. FIG. 5 shows only the rotary table 242 and the diffraction grating 243 in the spectroscopic unit 240 according to the second embodiment. Specifically, for each of the three optical paths divided by the optical path dividing unit 148, the optical paths are arranged in three stages in the direction perpendicular to the paper surface of FIG. 5A and in the vertical direction of the paper surface of FIG. It is composed of three diffraction gratings (diffraction gratings 243a, 243b, and 243c shown in FIG. 5B). That is, light having a wavelength of 400 to 520 nm reflected by the second dichroic mirror 148b is incident on the upper first diffraction grating 243a, and the first and second diffraction gratings 243b are incident on the first and second diffraction gratings 243b. Light having a wavelength of 520 to 640 nm transmitted through the dichroic mirrors 148a and 148b is incident, and light having a wavelength of 640 to 750 nm reflected by the first dichroic mirror 148a is incident on the third diffraction grating 243c in the lower stage.

  In the spectroscopic unit 240 according to the second embodiment, as shown in FIG. 5B, each of the diffraction gratings 243a to 243c configured in three stages has three rotations that can rotate on the same axis. The tables 242a, 242b, and 242c are attached independently. Further, by rotating each of the rotary tables 242a to 242c, a set of a plurality of prepared diffraction gratings 243 (a set made up of three stages of diffraction gratings 243a to 243c, which are respectively set to the rotary tables 242a to 242c). And three sets attached at different angles (2431a, 2432a, 2433a shown in FIG. 5A) can be arbitrarily selected. Therefore, in the spectroscopic unit 140 according to the above-described first embodiment, the angles of incidence on the diffraction gratings 143 of the three optical paths divided by the optical path splitting unit 148 are the first and second angles of the optical path splitting unit 148. The angle of the dichroic mirrors 148a and 148b and the first and second mirrors 148c and 148d is set according to the wavelength band of the light in each optical path. In the spectroscopic unit 240 according to the second embodiment, Since the angles of the three-stage diffraction gratings 243a to 243c may be set according to the wavelength band by rotating the rotary tables 242a to 242c, each of the three optical paths as shown in FIG. There is no need to change the angle of incidence on the diffraction grating. That is, as shown in FIG. 5A, when viewed from the direction of the diffraction grating groove of the diffraction grating 243 (any one of the diffraction gratings 2431 to 2433) (direction perpendicular to the paper surface of FIG. 5A). The three optical paths may overlap on the same straight line. Also in this case, according to the conditional expression (1), the center of the light diffracted by each of the diffraction gratings 243a to 243c is, for example, the direction of the groove of the diffraction grating with respect to the normal line of the second diffraction grating 243b. If the direction is 24 ° in the plane (in the plane of the groove in FIG. 5A) perpendicular to the plane (the direction perpendicular to the plane of FIG. 5A) (the pitch direction of the grooves), three optical paths The light of each wavelength band divided into 1 is within the respective light receiving regions of the first to third light receiving portions 145a to 145c arranged in the vertical direction, and is received without waste by the three arranged lines PMT. Can do.

  As described above, the spectroscopic system 1 according to the second embodiment having such a configuration can also configure the spectroscopic system 1 that can simultaneously acquire compact spectroscopic data with high wavelength resolution.

[Third Embodiment]
In the spectroscopic system 230 according to the second embodiment, the first and second dichroic mirrors 148a and 148b constituting the optical path splitting unit 148 are split so that the wavelength bands of light passing through the three optical paths are different. Although the case has been described, the first and second dichroic mirrors 148a and 148b can be formed of half mirrors. In this case, the light in the wavelength band included in the signal light introduced via the optical fiber 28 is divided into three optical paths with the same wavelength band. Therefore, by rotating the rotary tables 242a to 242c in FIG. 5B and making the number of engravings of the upper, middle and lower diffraction gratings 243a to 243c different, the spectral data of the same signal light is different. Can be acquired simultaneously with wavelength resolution (with different wavelength ranges). For example, as shown in FIG. 6A, while observing a wide range of 400 to 700 nm with a rough diffraction grating with a rough wavelength resolution (for example, 10 nm pitch), as shown in FIG. Can be observed with a fine diffraction grating and a fine wavelength resolution (for example, 2 nm pitch).

  In the first to third embodiments described above, the case where the signal light introduced into the spectroscopic units 140 and 240 is divided into three optical paths has been described. However, the number of divisions of the optical path is limited to these embodiments. However, it may be configured to be divided into two optical paths, or may be divided into four or more optical paths. Further, although the case where the PMT is used as the light receiving element of the light receiver 145 has been described, it may be configured by a CCD. Moreover, although the case where the diffraction gratings 143 and 243 are used as the spectroscopic elements has been described, a prism can also be used.

1 Spectroscopic system (scanning microscope with spectral function)
40, 140, 240 Spectroscopic system 41, 141 Collimator optical system 43, 143, 243 Diffraction grating (spectral element)
243a First diffraction grating 243b Second diffraction grating 243c Third diffraction grating 44, 144 Condensing optical system 45, 145 Light receiver 145a First light receiving area 145b Second light receiving area 145c Third light receiving area 148 Optical path Dividing unit 148a First dichroic mirror 148b Second dichroic mirror

Claims (10)

A collimator optical system that converts light into a substantially parallel light beam;
An optical path splitting unit that splits the substantially parallel light flux into a plurality of light fluxes;
A spectroscopic element for dispersing at least one of the plurality of light beams;
A rotary table in which a plurality of the spectral elements having different spectral characteristics are arranged ;
A light receiver for receiving the spectral light split by the spectral element, wherein the light receiving element is two-dimensionally arranged in a direction perpendicular to the wavelength dispersion direction of the spectral light; ,
Have a, a focusing optical system for focusing the light receiving element surface of the photodetector of the spectroscopic light from the spectral element,
A plurality of the rotary tables are arranged in a direction orthogonal to the wavelength dispersion direction,
By rotating each of the plurality of turntables, each spectroscopic element disposed on each turntable is configured to be movable to a position where at least one of the plurality of light beams is incident,
At least two of the plurality of light beams are respectively incident on the spectroscopic elements disposed on the different rotary tables . The spectroscopic unit according to claim 1 , wherein at least two of the plurality of spectroscopic elements on which the plurality of light beams are incident have different wavelength resolutions. Each of the plurality of rotary table, the spectral of claim 1 or 2, characterized in that is capable of changing configuration respectively the incident angle of the light beam incident on the spectral element arranged on the rotary table unit. The spectroscopic unit according to any one of claims 1 to 3, wherein the optical path dividing unit includes a dichroic mirror, and the dichroic mirror divides the light beam into at least two different wavelength bands. The spectroscopic unit according to any one of claims 1 to 3, wherein the optical path splitting unit includes a half mirror, and the half mirror splits the light flux in at least two identical wavelength bands. Spectroscopic unit according to any one of claims 1 to 5, characterized in that said light receiving element of the light receiver is PMT. Spectroscopic unit according to any one of claims 1 to 5, characterized in that said light receiving element of the light receiver is CCD. The spectroscopic unit according to claim 1, wherein the spectroscopic element is a diffraction grating. The spectroscopic unit according to claim 1, wherein the spectroscopic element is a prism. A microscope that scans the light from the light source and collects the light on the sample by the objective lens, and collects the light emitted from the sample by the objective lens;
A scanning microscope comprising: the spectroscopic unit according to any one of claims 1 to 9 that spectrally detects the light from the microscope.

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