JP7325736B2 - Optical measuring device - Google Patents

Description

The present invention relates to an optical measuring device.

As an optical measurement device capable of obtaining information on the chemical composition of a sample, a confocal optical system is used to detect Raman scattered light emitted from the sample when the sample is irradiated with excitation light. Spectroscopic devices are known. In such a confocal optical system, a pinhole is arranged at an imaging position conjugate to the focal position of the objective lens, and the objective lens converges the excitation light from the point light source to the focal position of the objective lens. there is As a result, the detected light is selectively acquired only from the specific position of the focused sample. Such a confocal Raman spectroscopic device can detect Raman scattered light only from a specific position of a sample to be measured and perform highly accurate measurement.

Also known is a multifocal confocal type Raman spectrometer capable of simultaneously acquiring multi-point spectra from a sample by irradiating the sample with a plurality of excitation lights in a two-dimensional array at predetermined intervals. (See Patent Documents 1 and 2).

JP 2012-237647 A JP-A-2014-10216

In a Raman spectroscopic apparatus using a confocal optical system as described above, it is not possible to simultaneously obtain spectral spectra at positions deviated from the focal point of the objective lens in the depth direction (thickness direction) of the sample. Therefore, in order to obtain the spectrum at each position in the depth direction, it is necessary to move the sample relative to the focal point of the objective lens in the direction of the optical axis of the objective lens, which takes time. I had a problem. Such problems include fluorescence spectrometers for measuring the spectroscopic spectrum of fluorescence emitted when a sample is irradiated with excitation light, and spectroscopic spectra of detected light transmitted or reflected when the sample is irradiated with infrared rays. The same applies to optical measurement devices using a confocal optical system, such as infrared spectrometers.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical measuring apparatus capable of simultaneously detecting detection light from each position in the depth direction of a sample.

The optical measurement apparatus of the present invention includes a light irradiation unit that irradiates a sample with measurement light condensed into a point, an objective lens that receives detection light emitted from the sample due to the irradiation of the measurement light, and the objective lens. a main optical system having an imaging lens for forming an image of the detection light from the main optical system; a detection optical system including a collimating lens that converts the incident detection light into parallel light; and a detection unit for detecting light from a position shifted from the focal position of the objective lens.

The optical measurement apparatus of the present invention includes a light irradiation unit that irradiates a sample with measurement light, an objective lens that receives detection light emitted from the sample by the irradiation of the measurement light, and an objective lens that connects the detection light from the objective lens. a main optical system having an imaging lens for imaging, a microlens array in which a plurality of microlenses are arranged and the detection light from the main optical system is incident, and corresponding to each microlens of the microlens array A fiber bundle provided with a plurality of optical fibers, in which light transmitted through the microlens is incident on one end of the plurality of optical fibers, and detection for detecting each light emitted from the other end of each optical fiber of the fiber bundle and a part.

According to the present invention, the detection light obtained through the main optical system from the sample irradiated by condensing the measurement light into a point is converted into parallel light through the collimating lens, and the center of the detection light from the collimating lens is converted to parallel light. Since the light at the position away from the axis is detected as the light from the position shifted from the focal position of the objective lens of the sample, the detection light from each position in the depth direction of the sample can be detected at the same time.

According to the present invention, since the detection light from the sample obtained through the main optical system is incident on one end of a plurality of optical fibers via the microlens array, each position in the depth direction of the sample from each optical fiber can be detected at the same time.

1 is an explanatory diagram showing the configuration of a Raman spectrometer according to a first embodiment; FIG. FIG. 4 is an explanatory diagram showing the arrangement of optical fibers on the incident end surface and the exit end surface of the fiber bundle; FIG. 4 is an explanatory diagram showing images formed by Raman scattered light from focal positions and non-focal positions; FIG. 4 is an explanatory diagram showing an example of the positional relationship between light beams corresponding to Raman scattered light from focal positions and non-focal positions and optical fibers; It is an explanatory view showing the layer structure of the measured sample. 4 is a graph showing Raman shifts obtained from light from two optical fibers; 4 is a graph showing the Raman spectrum peaks of Fe ₂ O ₃ in the upper layer and NiO in the lower layer and the light intensity ratio of NiO and Fe ₂ O ₃ in the light of each optical fiber for one row. It is an explanatory view showing the configuration of the Raman spectroscopic device of the second embodiment. 4 is an explanatory diagram showing the configuration of a light source section; FIG. FIG. 4 is an explanatory diagram showing an example of arrangement of optical fibers with respect to microlenses; FIG. 3 is an explanatory diagram for explaining light rays incident on each optical fiber;

[First embodiment]
In FIG. 1, the Raman spectroscopic device 10 simultaneously detects spectral spectra of Raman scattered light from positions at different depths of a sample S1.

A Raman spectroscopic device 10 as an optical measurement device includes a light source unit 12, a dichroic mirror 14, an objective lens 15, an imaging lens 16, a collimator lens 17, an edge filter 18, a microlens array 21, a fiber bundle 22, and a spectroscopic device as a detector. A detector 23 is provided. Among them, the light source unit 12, the dichroic mirror 14, and the objective lens 15 constitute a light irradiation unit, and the collimator lens 17, the edge filter 18, the microlens array 21, and the fiber bundle 22 constitute a detection optical system.

The light source unit 12 is composed of a laser light source which is a point-like light source for outputting laser light as excitation light, a collimating lens which collimates the laser light from the laser light source into parallel light, and the like. The dichroic mirror 14 reflects the excitation light from the light source unit 12 and transmits Raman scattered light having a wavelength longer than that of the excitation light. The light source unit 12 and the dichroic mirror 14 are adjusted so that the center of the excitation light reflected by the dichroic mirror 14 coincides with the optical axis P1 of the objective lens 15 (see FIG. 3). The objective lens 15 collects the excitation light reflected by the dichroic mirror 14 onto the sample S1, and collects the Raman scattered light emitted from the sample S1 during irradiation with the excitation light. In this example, the excitation light is the measurement light and the Raman scattered light is the detection light.

In this example, the light source unit 12 has an epi-illumination arrangement that irradiates excitation light through the objective lens 15, but may have a transmission illumination arrangement that irradiates the sample S1 with excitation light from the opposite side of the objective lens 15. Even in the case of the transmitted illumination arrangement, it is preferable to focus the excitation light on one point at the focal position of the objective lens 15 .

The imaging lens 16 constitutes a main optical system together with the objective lens 15, and converges the Raman scattered light transmitted through the dichroic mirror 14 to form an image. The collimating lens 17 converts the Raman scattered light emitted from the imaging lens 16 into substantially parallel light. For this reason, the collimator lens 17 is arranged, for example, so that the focal point on the object side (left side in the figure) substantially coincides with the focal point on the image side (right side in the figure) of the imaging lens 16 . The Raman scattered light emitted from different positions in the depth direction of the sample S1 and emitted from the collimator lens 17 has a cross section perpendicular to the optical axis P1, that is, the light flux emitted from the collimator lens 17. It is converted into a luminous flux (hereinafter referred to as a cylindrical luminous flux) having a ring-shaped (doughnut-shaped) centered on the central axis of and having a diameter corresponding to the amount of deviation from the focal position. Incidentally, the Raman scattered light that is actually converted into parallel light by the collimating lens 17 has a mountain-like light intensity distribution such that the ring-like portion has a peak.

In this Raman spectrometer 10, in addition to the Raman scattered light from the focal position of the objective lens 15, a position shifted in the depth direction (thickness direction) of the sample S1 with respect to the focal position (hereinafter referred to as a non-focal position) At the same time, the spectroscopic spectrum of the Raman scattered light from . Therefore, at the focal position of the imaging lens 16 on the image side and conjugate with the focal position of the objective lens 15 on the sample S1, that is, the condensing position of the excitation light, light from the non-focal position is cut. There is no pinhole or the like for Note that the depth direction of the sample S1 is the optical axis direction of the objective lens 15 .

The edge filter 18 is a long-pass filter that accurately removes the excitation light from the light emitted from the collimator lens 17 and transmits only the Raman scattered light. The position of the edge filter 18 is not particularly limited as long as it is behind the dichroic mirror 14 , and may be arranged between the dichroic mirror 14 and the imaging lens 16 , for example.

The microlens array 21 is integrally formed with a plurality of microlenses 21a arranged two-dimensionally. The microlens array 21 is arranged in a posture in which the optical axis of each microlens 21a is parallel to the optical axis P1. Each microlens 21a collects the Raman scattered light incident thereon. That is, part of the Raman scattered light from the collimator lens 17 is condensed. The microlens array 21 splits the Raman scattered light emitted from the collimator lens 17 into a plurality of light beams, and the split light beams are focused on the incident end surface of the fiber bundle 22 . In this example, the microlens array 21 has n×n microlenses 21a arranged in a matrix, where n is an integer of 2 or more. The two-dimensional arrangement of the microlenses 21a is not limited to a matrix arrangement, and may be arranged in a honeycomb arrangement, for example. In addition, in order to avoid complication of illustration, in FIG. 1, the number of micro lenses 21a is drawn smaller than the actual number.

The microlens array 21 efficiently causes the Raman scattered light to enter each optical fiber 22a constituting the fiber bundle 22, and suppresses crosstalk in which the Raman scattered light from the focal position and each non-focal position are mixed.

The fiber bundle 22 is a collection of the same number of optical fibers 22a as the microlenses 21a of the microlens array 21, and the optical fibers 22a and the microlenses 21a correspond one-to-one. The Raman scattered light from each microlens 21a is guided to the spectral detector 23 through the optical fiber 22a corresponding to the emitted microlens 21a.

The spectral detector 23 detects the spectral spectrum of Raman scattered light. The spectroscopic detector 23 is composed of a spectroscope that disperses Raman scattered light and a light intensity detector that detects the intensity of light for each wavelength of the Raman scattered light dispersed by the spectroscope, that is, a spectral spectrum. The spectral detector 23 detects the spectral spectrum of each Raman scattered light emitted from each optical fiber 22a. It should be noted that the spectral spectrum of the Raman scattered light from any one or a plurality of optical fibers 22a out of the optical fibers 22a may be detected.

As shown in FIG. 2A, one ends of optical fibers 22a of the fiber bundle 22 are arranged in a matrix on the incident end surface on the microlens array 21 side. One ends of the optical fibers 22a are arranged at the same pitch, number of rows and number of columns as the microlenses 21a. As a result, the Raman scattered light emitted from each microlens 21a enters the corresponding optical fiber 22a. On the other hand, as shown in FIG. 2B, the other ends of the optical fibers 22a are arranged in a line on the exit end face of the fiber bundle 22 on the spectroscopic detector 23 side. By this fiber bundle 22, each Raman scattered light from the focal position and the non-focal position emitted from the microlens array 21 in a state of two-dimensional distribution is output to the spectroscopic detector 23 in a state of one-dimensional arrangement. be.

As described above, the fiber bundle 22 develops each Raman scattered light beam from the focal position and the non-focal position into a line orthogonal to the direction of travel (the direction of emergence from the optical fiber 22a) and onto the spectroscopic detector 23. Since it is emitted, it is easy to detect the spectral spectrum.

Next, the action of the above configuration will be described. First, the sample S1 is placed on the stage (not shown) of the Raman spectrometer 10 . The stage is moved in the optical axis direction of the objective lens 15 to adjust the focal position of the objective lens 15 to, for example, a position slightly inside the sample S1 from the surface of the sample S1. The focal position of the objective lens 15 may be aligned with the surface of the sample S1, outside the sample S1, or deeper inside the sample S1. When the focal position of the objective lens 15 is inside the sample S1, the tubular beams of Raman scattered light from a pair of positions sandwiching the focal position may overlap. For this reason, when there is no need to detect the Raman scattered light from the sample S1 at such a pair of positions, or when the cylindrical light beams overlap and can be detected without any problem (for example, when they are known to have the same composition). ), it is preferable to set the focal position to be inside the sample S1.

A sample S1 is irradiated with excitation light from a light source unit 12 via a dichroic mirror 14 and an objective lens 15 . Raman scattered light is emitted from the sample S1 by irradiation with this excitation light. The Raman scattered light emitted from the sample S1 passes through the objective lens 15, the dichroic mirror 14, and the imaging lens 16 and enters the collimating lens 17. As shown in FIG.

As shown in FIG. 3A, the Raman scattered light emitted from the sample S1 is scattered not only from the focal position Fp of the objective lens 15 in the sample S1 but also from the non-focus position of the objective lens 15 on the optical axis P1. includes those from To simplify the explanation, it is assumed that Raman scattered light is emitted from the focal position Fp and three non-focal positions NFp1 to NFp3.

On the focal plane of the imaging lens 16, the Raman scattered light from the focal position Fp forms a point-like image R0, as shown in FIG. 3(B). On the other hand, the Raman scattered lights from the non-focus positions NFp1 to NFp3 form annular images R1 to R3 because they are shifted from the focus position Fp. The images R1 to R3 are concentric circles centered on the image R0, and the diameters of the images R1 to R3 become larger as the deviation from the focal position Fp increases.

The Raman scattered light that forms the images R0 to R3 as described above is converted into parallel light by the collimating lens 17. FIG. That is, the Raman scattered light from the focal position Fp is converted into a light flux having a circular cross section, and the Raman scattered light from the non-focal positions NFp1 to NFp3 is ring-shaped and has a diameter corresponding to the amount of deviation from the focal position Fp. is converted into a cylindrical luminous flux with

As schematically shown in FIG. 4, the Raman scattered light that has passed through the collimating lens 17 is condensed by the microlenses 21a at positions through which the light beams B0 to B4 corresponding to the images R0 to R3 respectively pass. It enters one end of the corresponding optical fiber 22a. That is, the Raman scattered light from the non-focus positions NFp1 to NFp3k shifted from the focal position Fp is incident on each optical fiber 22a distant from the optical axis P1, and the larger the deviation from the focal position Fp, the more the Raman scattered light from the optical axis P1. The light is incident on each optical fiber 22a which is widely separated. The Raman scattered light beams B0 to B4 incident on the optical fiber 22a pass through the optical fiber 22a and are emitted to the spectroscopic detector 23 from the other end.

Then, the spectral detector 23 detects the spectral spectrum of each of the Raman scattered lights emitted from the optical fiber 22a. As a result, spectral spectra of Raman scattered light from the focal position Fp and the non-focal positions NFp1 to NFp3 are simultaneously detected. The spectroscopic spectrum thus detected corresponds to any non-focus position of the sample S1 in the depth direction depending on the position of one end of the optical fiber 22a that emits the Raman scattered light that is the source of the spectroscopic spectrum. can be identified. Thus, without moving the focal position of the objective lens 15 with respect to the sample S1, a spectrum is obtained at each position in the depth direction of the sample S1.

Using the above configuration, the spectroscopic spectrum of Raman scattered light was detected for the sample S1 having the layer structure shown in FIG. In the sample S1, a first layer 31 made of Fe ₂ O ₃ (iron (III) oxide) and a second layer 32 made of NiO (nickel oxide) are laminated in order from the top to form a silicon oxide (SiO ₂ ) film 33 . It is a structure laminated on top. The thicknesses of the first layer 31 and the second layer 32 were each 100 nm. The stage on which the sample S1 was placed was adjusted so that the focal position of the objective lens 15 was within the first layer 31 slightly shifted from the surface of the first layer 31 .

As the microlens array 21, as shown in FIG. 4, 11×11 microlenses 21a were arranged in a matrix. Correspondingly, the fiber bundle 22 has one end of the optical fibers 22a arranged in 11 rows×11 columns on the incident end face. 4, X0, X1, . The optical fiber 22a is specified using each position in the row direction and the column direction.

The optical fiber 22a at the position X5Y5 where the Raman scattered light is estimated to enter from the focal position (in the first layer 31) of the objective lens 15, and the Raman scattered light from the non-focus position in the second layer 32 is assumed to enter. FIG. 5 shows the Raman shifts obtained from the results of detecting the spectral spectrum of the light emitted from the optical fiber 22a at the position X5Y2. A peak peculiar to Fe ₂ O ₃ of the first layer 31 was detected in the Raman shift of the light from the optical fiber 22a at position X5Y5. Also, a peak specific to NiO of the second layer 32 was detected in the Raman spectrum of the light from the optical fiber 22a at position X5Y2.

Further, FIG. 7 shows the light intensity ratio of the light from each optical fiber 22a arranged in the row direction at the position Y5. The light intensity ratio (Fe ₂ O ₃ /NiO) is the ratio of the light intensity of Fe ₂ O ₃ (395 cm ⁻¹ ) of the first layer 31 to NiO (455 cm ⁻¹ ) of the second layer 32 . The light intensity ratio (NiO/Fe ₂ O ₃ ) is the ratio of the light intensity of NiO (455 cm ⁻¹ ) of the second layer 32 to Fe ₂ O ₃ (395 cm ⁻¹ ) of the first layer 31 . As can be seen from these light intensity ratios, it can be seen that the light intensity ratio changes greatly due to the shift in the depth direction from the focus position, and it can be seen that the light from the focus position and each non-focus position can be detected separately.

In the above example, the Raman scattered light from the collimator lens is injected into the fiber bundle via the microlens array, but the microlens array is omitted and the Raman scattered light from the collimator lens is injected directly into the fiber bundle. You may let Alternatively, a microlens array in which a plurality of microlenses are arranged in a line may be used to obtain Raman scattered light emitted from a collimating lens only in a one-dimensional direction perpendicular to the optical axis of the objective lens. Alternatively, a microlens array in which a plurality of microlenses are arranged in a line may be moved or rotated within a plane perpendicular to the optical axis of the objective lens to scan the Raman scattered light emitted from the collimator lens. Furthermore, one microlens may be moved within a plane orthogonal to the optical axis of the objective lens to acquire Raman scattered light emitted from the collimator lens at a desired position. Note that, even in the above configuration, the number of optical fibers can be the same as that of the microlenses. It is also possible to omit the fiber bundle and detect the spectrum using Raman scattered light emitted from one microlens or microlenses arranged in a line.

[Second embodiment]
The Raman spectroscopic device of the second embodiment simultaneously detects spectral spectra of Raman scattered light in the plane direction and the thickness direction of the sample.

In FIG. 8, a Raman spectroscopic device 50 as an optical measurement device includes a light source unit 52, a dichroic mirror 54, an objective lens 55, an edge filter 56, an imaging lens 57, a microlens array 58, a fiber bundle 61, and a spectroscopic device as a detection unit. A detector 62 and a data calculator 63 are provided. Among these, the light source unit 52, the dichroic mirror 54, and the objective lens 55 constitute a light irradiation unit, and the microlens array 58 and fiber bundle 61 constitute a detection optical system.

The light source unit 52 outputs a plurality of excitation lights. As an example is shown in FIG. 9, the light source unit 52 includes a laser light source 65, a beam expander 66, a microlens array 67, a pinhole plate 68 in which a plurality of pinholes are two-dimensionally arranged, and a collimator lens 69. The laser light source 65 is a point-like light source that outputs laser light as excitation light. A laser beam output from a laser light source 65 is converted into a parallel beam having a large diameter by a beam expander 66 and is split into beams having a small diameter for each microlens by a microlens array 67 .

Each pinhole of the pinhole plate 68 is arranged at the focal point of each microlens of the microlens array 67 . Each light beam emitted from the microlens array 67 and transmitted through each pinhole of the pinhole plate 68 is emitted toward the dichroic mirror 54 as parallel excitation light by the collimator lens 69 . The light source unit 52 and the dichroic mirror 54 are adjusted so that each excitation light reflected by the dichroic mirror 54 is parallel to the optical axis P2 of the objective lens 55 (see FIG. 8). The objective lens 55 collects each excitation light reflected by the dichroic mirror 54 onto the sample S2. As a result, the sample S2 is irradiated with a plurality of excitation lights in a matrix. As a result, the sample S2 is irradiated with a plurality of excitation lights arranged two-dimensionally in a matrix at predetermined intervals.

Although the light source unit 52 in this example is arranged for epi-illumination in which excitation light is emitted through the objective lens 55, it may be arranged for transmitted illumination in which each excitation light is emitted to the sample S2 from the opposite side of the objective lens 55.

The objective lens 55 collects the Raman scattered light emitted from the sample S2 during irradiation with a plurality of excitation lights. The dichroic mirror 54 reflects the excitation light from the light source unit 52 and transmits Raman scattered light having a longer wavelength than the excitation light.

As shown in FIG. 8, the edge filter 56 arranged between the dichroic mirror 54 and the imaging lens 57 is composed of a long-pass filter, and removes the excitation light from the light transmitted through the dichroic mirror 54 with high accuracy. Only scattered light is transmitted. The imaging lens 57 collects and forms an image of the Raman scattered light that has passed through the edge filter 56 .

The Raman spectrometer 50 detects the depth of the sample S2 from each condensing point in addition to the Raman scattered light from the condensing point of each excitation light on the sample S2, that is, the irradiated portion of the excitation light on the focal plane of the objective lens 55. The spectrum of Raman scattered light from a position shifted in the depth direction (thickness direction) (hereinafter referred to as a non-focus position) is also detected at the same time. For this reason, the image-side focal plane of the imaging lens 57 is not provided with a pinhole or the like for cutting light from other than the condensing point of each excitation light. Note that the depth direction of the sample S2 is the optical axis direction of the objective lens 55 .

The microlens array 58 has a plurality of microlenses 58a arranged two-dimensionally in a matrix. The microlens array 58 is arranged near the focal position of the imaging lens 57 in such a posture that the optical axis of each microlens 58a is parallel to the optical axis P2. The microlens array 58 may be arranged at the focal position of the imaging lens 57, or may be arranged behind or in front of the focal position.

The fiber bundle 61 is composed of a plurality of optical fibers 61a in the same manner as the fiber bundle of the first embodiment. On the side end surface, the other ends of the optical fibers 61a are arranged in a line.

As shown in FIG. 10, one ends of a plurality of optical fibers 61a face each microlens 58a in a matrix arrangement. In the example of FIG. 10, one ends of four optical fibers 61a face one microlens 58a in a state of being arranged in two rows and two columns. In the following description, a plurality of optical fibers 61a corresponding to one microlens 58a will be collectively referred to as a fiber unit.

The spectroscopic detector 62 detects the spectroscopic spectrum of the Raman scattered light, as in the first embodiment, and is composed of a spectroscope, a light intensity detector, and the like. This spectral detector 62 also detects the spectral spectrum of each Raman scattered light from each optical fiber 61a. The data calculation unit 63 performs refocusing processing similar to that of a light field camera, and rearranges and displays the spectral spectra so as to group the spectral spectra for each depth of the sample S2, for example. When performing such a display, for example, the spectral spectrum obtained from the optical fiber 61a at the relatively same position for each fiber unit on the incident end face can be treated as the spectral spectrum obtained from the same depth position of the sample S2. Just do it.

The above configuration is for detecting a light field. A main optical system 71 consisting of an objective lens 55 and an imaging lens 57, a microlens array 58 constituting a detection optical system, and optical fibers 61a of a fiber bundle 61 are a light field camera taking lens, a microlens array, and an image sensor. It is the same as the relationship with the light receiving element of the sensor.

The operation of the Raman spectrometer 50 will be described. A plurality of excitation lights from the light source unit 52 are applied to the sample S2 via the dichroic mirror 54 and the objective lens 55 . At this time, the sample S2 is irradiated with a plurality of excitation lights arranged in a matrix in a two-dimensional direction perpendicular to the optical axis P2.

Raman scattered light is emitted from each portion of the sample S2 irradiated with each excitation light. At this time, the Raman scattered light is emitted not only from each portion of the focal plane of the objective lens 55 in the sample S2, but also from each portion in the depth direction of each portion irradiated with the excitation light.

The Raman scattered light emitted as described above is collected by the objective lens 55 , passes through the dichroic mirror 54 and the edge filter 56 , and is collected by the imaging lens 57 . The Raman scattered light focused by the imaging lens 57 is incident on the incident end face of the fiber bundle 61 via the microlens array 58, and is transmitted from the other end of each optical fiber 61a arranged in a line to the spectroscopic detector. 62 is injected. The spectral detector 62 detects the spectral spectrum of the Raman scattering light thus emitted from the other end of each optical fiber 61a.

By the way, the ray of Raman scattered light emitted from the sample S2 passes through one of the optical fibers 61a according to the position (height from the optical axis P2) of the main optical system 71 through which it passes and the angle of the ray. incident on one end of As schematically shown in FIG. 11 for the case where the rays of Raman scattered light pass through the central portion of the main optical system 71, the Raman scattered light emitted from different positions in the in-plane direction of the sample S2 perpendicular to the optical axis P2. Each light beam is incident on different microlenses 58a, and is incident on the optical fiber 61a corresponding to the microlens 58a into which each light beam is incident. Also, the rays of Raman scattered light emitted from the same position in the in-plane direction of the sample S2 but different depths are incident on the same microlens 58a, but are incident on different optical fibers 61a.

As described above, each light beam of Raman scattered light from the sample S2 is incident on each optical fiber 61a, and as shown in FIG. It becomes the in-plane position information in the in-plane direction of the sample S2. Further, within the fiber unit of each microlens 58a, the position of one end of the optical fiber 61a serves as positional information in the direction of the optical axis P2 from which the Raman scattered light beam is emitted, that is, depth information. Therefore, without moving the focal position of the objective lens 55 with respect to the sample S2, the position of each optical fiber 61a is associated with the three-dimensional positional information of the sample S2 in the in-plane direction and the depth direction. A spectroscopic spectrum of Raman scattered light can be obtained at the same time.

The Raman spectrometer 50 obtains four-dimensional information obtained by adding spectroscopic information to three-dimensional positional information of each point in the in-plane direction and depth direction of the sample S2. This four-dimensional information can be obtained as two-dimensional information because the optical fibers 61a are arranged in a line on the exit end face of the fiber bundle 61. FIG.

In the above example, the sample is irradiated with a plurality of excitation light beams at the same time. Alternatively, the sample may be irradiated with planar excitation light. Furthermore, instead of a microlens array in which microlenses are arranged two-dimensionally, a microlens array in which a plurality of microlenses are arranged in a line is used, and this microlens array is moved or moved in a plane perpendicular to the optical axis of the objective lens. You can rotate it. Note that, even in the above configuration, the number of optical fibers can be the same as that of the microlenses.

In each of the above embodiments, for example, as proposed in International Publication No. WO 2014/097886, metal nanoparticles are provided on the sample-side surface of an optical device that is arranged close to the sample surface and is capable of transmitting light. A configuration may be employed in which surface plasmons are excited on the surface of the particles close to the sample to enhance the Raman scattered light from the sample.

Moreover, although the Raman spectroscopic device is described in each of the above embodiments, the optical measurement device is not limited to this. For example, as an optical measurement device, a fluorescence spectrometer that measures the spectral spectrum of fluorescence as detection light emitted when a sample is irradiated with excitation light as measurement light, a sample is irradiated with infrared light as measurement light, An infrared spectroscopic device or the like that obtains the spectral spectrum of transmitted or reflected detection light may also be used.

Reference Signs List 10, 50 Raman spectrometer 12, 52 light source unit 15, 55 objective lens 16, 57 imaging lens 17 collimating lens 21, 58 microlens array 22, 61 fiber bundle 23, 62 spectroscopic detector 71 main optical system

Claims (8)

a light irradiation unit that collects and irradiates measurement light into a point on the sample;
a main optical system having an objective lens into which detection light emitted from the sample by irradiation with the measurement light is incident and an imaging lens that forms an image of the detection light from the objective lens;
A collimator for converting the detection light including the light from the sample deviated from the focal position of the objective lens in the optical axis direction of the main optical system into parallel light from the main optical system, and converting the incident detection light into parallel light. detection optics including a lens;
a detection unit that detects light at a position away from the central axis of the detection light emitted from the collimator lens as light from a position shifted from the focus position of the objective lens of the sample ,
The optical measurement apparatus according to claim 1, wherein the detection optical system is arranged on the image side of the collimator lens and includes one or a plurality of microlenses for condensing part of the detection light emitted from the collimator lens. a light irradiation unit that collects and irradiates measurement light into a point on the sample;
a main optical system having an objective lens into which detection light emitted from the sample by irradiation with the measurement light is incident and an imaging lens that forms an image of the detection light from the objective lens;
A collimator for converting the detection light including the light from the sample deviated from the focal position of the objective lens in the optical axis direction of the main optical system into parallel light from the main optical system, and converting the incident detection light into parallel light. detection optics including a lens;
a detection unit that detects light at a position away from the central axis of the detection light emitted from the collimator lens as light from a position shifted from the focus position of the objective lens of the sample,
Optical measurement, wherein the detection optical system comprises a microlens array in which each of a plurality of microlenses arranged in a matrix converges part of the detection light emitted from the collimating lens. Device. The detection optical system includes a plurality of optical fibers corresponding to the respective microlenses of the microlens array, and has an incident end surface on which one ends of the plurality of optical fibers are arranged in a matrix and the other ends of the plurality of optical fibers. are arranged in a line, and has a fiber bundle into which light from the microlenses of the microlens array corresponding to one end of each of the plurality of optical fibers is incident,
3. The optical measurement apparatus according to claim 2 , wherein the detection section has a spectroscope into which the light from the exit end surface is incident. The light irradiation unit irradiates the sample with excitation light as the measurement light,
The detection optical system emits Raman scattered light from the sample as the detection light,
The optical measurement apparatus according to any one of Claims 1 to 3 , wherein the detection unit detects a spectrum of Raman scattered light. a light irradiation unit that collects and irradiates measurement light into a point on the sample;
a main optical system having an objective lens into which detection light emitted from the sample by irradiation with the measurement light is incident and an imaging lens that forms an image of the detection light from the objective lens;
A collimator for converting the detection light including the light from the sample deviated from the focal position of the objective lens in the optical axis direction of the main optical system into parallel light from the main optical system, and converting the incident detection light into parallel light. detection optics including a lens;
a detection unit that detects light at a position away from the central axis of the detection light emitted from the collimator lens as light from a position shifted from the focus position of the objective lens of the sample,
The light irradiation unit irradiates the sample with excitation light as the measurement light,
The detection optical system emits Raman scattered light from the sample as the detection light,
The detection unit detects a spectrum of Raman scattered light
An optical measuring device characterized by: a light irradiation unit that irradiates a sample with measurement light;
a main optical system having an objective lens into which detection light emitted from the sample by irradiation with the measurement light is incident and an imaging lens that forms an image of the detection light from the objective lens;
a microlens array in which a plurality of microlenses are arranged and on which the detection light from the main optical system is incident;
a fiber bundle in which a plurality of optical fibers are provided corresponding to each microlens of the microlens array, and light transmitted through the microlenses is incident on one end of the plurality of optical fibers;
and a detector that detects each light emitted from the other end of each optical fiber of the fiber bundle. The fiber bundle has an incident end face in which one ends of the plurality of optical fibers are arranged in a matrix and an exit end face in which the other ends of the plurality of optical fibers are arranged in a line,
7. The optical measurement apparatus according to claim 6, wherein the detection section has a spectroscope into which the light from the exit end surface is incident. The light irradiation unit irradiates the sample with excitation light as the measurement light,
The fiber bundle emits Raman scattered light from the sample as the detection light,
The optical measurement device according to claim 6 or 7, wherein the detection unit detects a spectrum of Raman scattered light.

Images