JPH06300633A - Fourier spectrometric image measuring equipment - Google Patents

Abstract

PURPOSE:To provide the Fourier spectrometric image measuring equipment for measuring the spectrum of the light to be measured at each point on an object by passing the light to be measured emitted from an object spreading two-dimensionally through an interferometer and subjecting the detection signal of brightness to Fourier transform in which downsizing is realized while ensuring a wide view and sufficient quantity of measuring light and stray light from parts other than a measuring pint is removed. CONSTITUTION:A two-dimensional imaging lens array 12 constituting a normal focus system is disposed at an incident position of light 11 to be measured. A pinhole plate 13 having a plurality of pinholes 13a for passing the light 11 condensed by each leans 12a in the lens array 12 is disposed at the imaging position of the two-dimensional imaging lens array 12. The light passed through the pinhole 13a is then passed through a two-dimensional collimate lens array 14 and introduced to an interferometer where the pinhole plate 13 is subjected to two-dimensional scanning within the imaging position by a two-dimensional scanning means 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention interferes light under measurement emitted from an object having a two-dimensional spread with an interferometer, and Fourier-transforms a signal for detecting light and darkness of the light due to the interference to perform measurement under measurement. The present invention relates to a Fourier-spectroscopic image measuring device that measures the spectrum of light at each point of the object.

[0002]

2. Description of the Related Art Conventionally, various spectroscopic measurement devices for measuring the spectrum of light to be measured have been provided, and part 1
As one, a Fourier spectroscopy measuring device is also known. This Fourier spectroscopy measuring device measures the spectrum of the light under measurement by interfering the light under measurement with an interferometer and Fourier-transforming a signal in which the light and darkness of the light due to the interference is detected.
Also, a Fourier spectroscopic image measuring apparatus has been already proposed, which utilizes this Fourier spectroscopic measuring apparatus to spectroscopically measure light emitted from an object having a two-dimensional spread for each point of the object.

Conventionally, in this Fourier spectroscopic image measuring apparatus, a general image forming lens system including a normal convex lens is used to collect and collimate light emitted from an object and guide it to an interferometer. It was being done.

[0004]

This Fourier spectroscopic image measuring device is often used for spectroscopically measuring extremely weak light, such as spectroscopically measuring fluorescence emitted from a living body. In that case, it is desirable to secure a wide field of view (observation range) and to capture as much measurement light amount as possible.

However, in the conventional Fourier spectroscopic image measuring device using the general image forming lens system including the normal convex lens as described above, the image forming lens system is attempted to satisfy this requirement. However, the problem of being complicated and large is recognized.

Further, in the conventional Fourier spectral image measuring apparatus using this general imaging lens system, a large amount of stray light from a portion other than the observation point (especially in the depth direction) enters the imaging lens system. However, that leads to a decrease in the accuracy of spectroscopic measurement.

The present invention has been made in view of the above circumstances, can be formed in a small size with a large field of view and a large amount of measurement light, and can also eliminate stray light from portions other than the observation point. It is an object of the present invention to provide a Fourier-spectroscopic image measuring device.

[0008]

A Fourier-spectroscopic image measuring device according to the present invention is, as described above, a refractive index distribution type device arranged at a position where light to be measured emitted from an object having a two-dimensional spread is incident. A two-dimensional image forming lens array forming an erect image forming system such as a lens array or a microlens array, and a measured light which is arranged at an image forming position by the two-dimensional image forming lens array and converged by each lens of the lens array. A pinhole plate having a plurality of pinholes for passing through each of the pinholes, a scanning means for two-dimensionally scanning the pinhole plate within the image forming position, and the measured light passing through each pinhole of the pinhole plate. A two-dimensional collimating lens array composed of a plurality of parallelized lenses and the light to be measured that has passed through the two-dimensional collimating lens array are split into two light beams, and then 1 An optical system for combining the light beams, the 2
Means for modulating the optical path length of at least one of the two light fluxes,
A two-dimensional photodetector comprising a plurality of light-receiving elements combined in an array and detecting the light intensity of one light flux synthesized by the optical system at each position in the light flux, and the two-dimensional photodetector. Signal processing means for Fourier-transforming the output signal of each light-receiving element to obtain the spectrum of the measured light at each point on the object.

In a preferred embodiment of the present invention,
The above-mentioned scanning means is configured to also two-dimensionally scan the two-dimensional collimating lens array integrally with the pinhole plate.

[0010]

In the above structure, the erect image of the object is formed by the two-dimensional image forming lens array. Since the pinhole plate is arranged at the image forming position, only light at discrete positions on the image forming surface passes through the pinhole and 2
Collimated by a three-dimensional collimating lens array,
It is guided to an interferometer consisting of the above optical system and optical path length modulation means. Therefore, first, with the pinhole plate and the two-dimensional collimator lens array arranged at predetermined positions, the output signals of the respective light receiving elements of the two-dimensional photodetector associated with the optical path length modulation are Fourier transformed by the signal processing means,
The spectrum of the light to be measured is obtained with respect to scattered points on the object.

Each time the pinhole plate or the two-dimensional collimating lens array is moved by a small distance by the scanning means, the output signal of each light receiving element of the two-dimensional photodetector accompanying the optical path length modulation is signaled. If the Fourier transform is performed by the processing means, the two-dimensional spectral image information about the object can be obtained in such a manner that the spaces between the discrete points on the object are successively filled.

[0012]

The two-dimensional imaging lens array and the two described above are provided.
The two-dimensional collimator lens array can have a large NA (numerical aperture) in comparison with a general imaging lens system including an ordinary convex lens and the like, although it can be formed thin as a whole. Therefore, in the Fourier-spectroscopic image measuring device of the present invention using these lens arrays, the lens system portion can be made compact while securing a sufficient amount of measurement light, and thus can be made compact as a whole.

The two-dimensional image forming lens array and the two-dimensional collimating lens array can secure a large field of view only by increasing the number of lens elements constituting them, and even in such a case, an object which emits the measured light is measured. Since the distance to can be kept short, the Fourier spectroscopy image measuring apparatus of the present invention using these lens arrays,
While realizing miniaturization, a large field of view can be secured.

In the Fourier spectroscopic image measuring device according to the present invention, stray light from a portion other than the observation point of the object is blocked by the pinhole plate, so that the accuracy of spectroscopic measurement is also improved. Further, since the stray light is removed in this way, it is possible to perform sectioning in the depth direction of the object when measuring a spectral image of the object having high light transmittance.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the embodiments shown in the drawings. FIG. 1 shows a Fourier spectroscopy image measuring apparatus according to an embodiment of the present invention. As shown in the drawing, the measured light 11 such as fluorescence emitted from the sample 10 having a two-dimensional spread is a two-dimensional image forming an upright imaging system including a gradient index lens array, a microlens array, and the like. The light enters the image lens array 12 and is converged by each lens 12a forming the lens array 12. In this way, the erect image of the sample 10 is formed at the convergence position of the measured light 11.

At this image forming position, a pinhole plate 13 having a plurality of pinholes 13a for passing the converged light under measurement 11 is arranged. These pinholes 13a
The light to be measured 11 that has passed through each of them enters a collimating lens array 14 including a gradient index lens array, a microlens array, and the like, and is collimated by each lens 14a forming the lens array 14. In FIG. 1, the light to be measured 11 that is collimated by one lens 14a is used.
And the dark portion between the light to be measured 11 parallelized by the lens 14a adjacent thereto is hatched (the same applies to FIG. 2).

The collimator lens array 14 and the pinhole plate 13 have a two-dimensional scanning means 16 formed by combining two laminated piezoelectric elements, for example, via a common holding member 15.
Are linked to. The two-dimensional scanning means 16 is driven and controlled by the scanning control circuit 17, and the collimator lens array 14
The pinhole plate 13 is integrally moved in the X direction (direction perpendicular to the paper surface of the drawing) and in the Y direction by a small predetermined amount. When the two-dimensional scanning means 16 is driven in this way, the pinhole plate 13 moves within the imaging position of the two-dimensional imaging lens array 12.

The light to be measured which is collimated as described above
Part of the beam 11 is reflected by the beam splitter 18, and the remaining part of the beam 11 is transmitted therethrough to be split into two light beams. The reflected light 11A and the transmitted light 11B thus divided are respectively moved by the movable mirror 1.
9. The light is reflected by the fixed mirror 21 and returns to the beam splitter 18, where it is again combined into one light beam. The movable mirror 19 is reflected light together with the actuator 20 such as a laminated piezo element.
It constitutes a means for modulating the optical path length of 11 A, and can be reciprocated in the direction of arrow A by this actuator 20.

Light to be measured 11C after being combined into one light beam
Enters a two-dimensional photodetector 22 in which light receiving elements 22a such as photodiodes are arranged side by side vertically and horizontally, and the light intensity thereof is detected by the photodetector 22. Two-dimensional photo detector
The photodetection signal S output from each light receiving element 22a of 22 is subjected to processing such as amplification and A / D conversion in the detection circuit 23, and then input to the signal processing means 24. This signal processing means 24
Is composed of a well-known computer system together with a memory 25 and a reconstructing means 26 which will be described later, and a display means 27 such as a CRT display device is connected to the reconstructing means 26.

When performing the spectroscopic image measurement by the Fourier spectroscopic image measuring device having the above configuration, first, the pinhole plate 13
And the actuator 20 is driven with the collimator lens array 14 placed at predetermined initial positions in the X and Y directions,
The movable mirror 19 is moved in the above direction. Thus reflected light 11
When the optical path length of A is modulated and the transmitted light 11B is combined by the beam splitter 18, interference occurs between the two. Therefore, each light receiving element 22a of the photodetector 22 is
The light detection signal S output by the signal changes on the time axis as shown in FIG. 3 according to the contrast of the measured light 11C due to interference, that is, corresponding to the optical path length difference of the reflected light 11A.

The size of each light receiving element 22a of the photodetector 22 is
It is sufficiently smaller than the beam cross section of the measured light 11 which is collimated by one lens 14a of the collimator lens array 14. Then, the signal processing means 24 averages the photodetection signals S of a predetermined number of light receiving elements 22a adjacent to each other, and the like, so that each lens 12 of the two-dimensional imaging lens array 12 is processed.
The light detection signal S for each observation point on the sample 10 facing a is obtained. Then, the signal processing means 24 Fourier transforms the interferogram of the photodetection signal S for each observation point. This Fourier transform is the same as that conventionally performed, and the spectrum of the measured light 11 is obtained for each pixel, that is, for each lens 12a of the two-dimensional imaging lens array 12 by this Fourier transform processing. Sample obtained in this way
The spectrum for each of the discrete observation points on 10 is stored in the memory 25.

Each time the above operation is performed once, the scanning control circuit 17 drives the two-dimensional scanning means 16 once to move the pinhole plate 13 and the collimator lens array 14 by a predetermined distance. That is, the pinhole plate 13 and the collimator lens array 14 are first placed at the initial positions in the X and Y directions, and are moved a predetermined distance in the X direction each time the above operation is performed once. This moving distance p is set sufficiently smaller than the arrangement pitch of the lenses 12a of the two-dimensional imaging lens array 12. When this movement is performed a predetermined number of times m and the total movement distance in the X direction reaches the arrangement pitch of the lenses 12a, the pinhole plate 13 and the collimator lens array 14 are returned to the initial position in the X direction, and in the Y direction. It is moved a predetermined distance. This moving distance q is also set to be sufficiently smaller than the arrangement pitch of the lenses 12a of the two-dimensional imaging lens array 12. When this movement is performed n times, and the total movement distance in the Y direction reaches the arrangement pitch of the lenses 12a, and the movement in the X direction is performed m times, the pinhole plate 13 and the collimator lens array 14 are moved. XY scanning is completed. Note that normally, m = n and p = q may be set.

As described above, every time the pinhole plate 13 and the collimator lens array 14 are moved, the spectra for each of the discrete observation points on the sample 10 are obtained, and these spectra are sequentially stored in the memory 25. . Therefore, when the XY scanning of the pinhole plate 13 and the collimator lens array 14 is completed, the spectrum information stored in the memory 25 is read out and subjected to the reconstruction processing by the reconstruction means 26, thereby jumping over the sample 10. The two-dimensional spectroscopic image information on the sample 10 can be obtained by filling the space between the observation points. The two-dimensional spectral image information regarding the sample 10 thus obtained is displayed on the display means 27 or recorded by a recording means (not shown).

The above-mentioned two-dimensional imaging lens arrays 12 and 2
The three-dimensional collimator lens array 14 can have a large NA (numerical aperture) in comparison with a general imaging lens system including an ordinary convex lens, although it can be formed thin as a whole. Therefore, in this Fourier spectroscopy image measuring device using these lens arrays 12 and 14, the lens system portion can be made compact while securing a sufficient amount of measurement light, and as a result, it can be made compact as a whole.

The two-dimensional image forming lens array 12 and the two-dimensional collimating lens array 14 can secure a large field of view only by increasing the number of lens elements constituting them. Emitting sample
Since the distance up to 10 can be kept short, this Fourier spectroscopic image measurement device can be downsized while ensuring a large field of view.

In this Fourier spectroscopic image measuring device, stray light from a portion other than the observation point of the sample 10 is blocked by the pinhole plate 13, so that the accuracy of spectroscopic measurement is also high.

As shown in FIG. 3, only the pinhole plate 13 is connected to the two-dimensional scanning means 16, and the pinhole plate 13 is connected.
Only one of them may be two-dimensionally scanned. However, in that case, as shown in the drawing, when the optical axes of the lens 14a of the collimating lens array 14 and the pinhole 13a are deviated from each other, the measured light 11 which is collimated is obliquely emitted from the lens 14a. . The angle of this oblique emission changes according to the scanning position of the pinhole plate 13, and therefore the measured light
The incident position of the 11C on the photodetector 22 (see FIG. 1) also changes. Therefore, in this case, the position of the dark portion generated between the measured light 11 and the measured light 11 is detected by the photodetector 22, and the pixels are matched based on the detected position.

[Brief description of drawings]

FIG. 1 is a schematic side view of an apparatus according to an embodiment of the present invention.

FIG. 2 is a partial side view of an apparatus according to another embodiment of the present invention.

3 is a waveform diagram of a photodetector signal in the device of FIG.

[Explanation of symbols]

 10 sample 11 measured light 11A reflected light 11B transmitted light 12 two-dimensional imaging lens array 12a, 14a lens 13 pinhole plate 13a pinhole 14 collimating lens array 15 holding member 16 two-dimensional scanning means 17 scanning control circuit 18 beam splitter 19 Movable mirror 20 Actuator 21 Fixed mirror 22 Two-dimensional photodetector 22a Photodetector 23 Detection circuit 24 Signal processing means 25 Memory 26 Reconfiguring means 27 Display means

Claims (2)

[Claims] 1. A two-dimensional imaging lens array forming an erecting imaging system, which is arranged at a position where light to be measured emitted from an object having a two-dimensional spread enters. Is placed at the image formation position by
A pinhole plate having a plurality of pinholes through which the measured light converged by each lens of the lens array passes, a scanning means for two-dimensionally scanning the pinhole plate within the image forming position, and the pinhole plate A two-dimensional collimating lens array including a plurality of lenses for collimating the measured light that has passed through each of the pinholes, and dividing the measured light that has passed through the two-dimensional collimator lens array into two light beams, and An optical system that combines the two light fluxes, a means that modulates the optical path length of at least one of the two light fluxes, and a plurality of light receiving elements that are combined in an array, and the light of one light flux that is combined by the optical system. A two-dimensional photodetector for detecting the intensity at each position in the light flux, and the Fourier transform of the output signal of each light-receiving element of the two-dimensional photodetector to perform the Fourier transform of the measured light. Fourier spectral image measurement apparatus comprising a signal processing means for determining the spectrum for each point on the object. 2. The Fourier spectroscopic image measuring device according to claim 1, wherein the scanning means also two-dimensionally scans the two-dimensional collimating lens array integrally with the pinhole plate.