Optical system and area spectrometer

Abstract

To provide a plane spectroscopic device that is advantageous in downsizing, high resolution, or high efficiency.SOLUTION: An optical system to divide a light flux has: a first curved mirror provided with an opening part for passing the light flux from an object plane or a transmission part for transmitting the light flux; a second reflection part that has a plurality of reflection planes for dividing the light flux from the opening part or the transmission part of the first curved mirror, and reflects the light fluxes divided by the respective reflection planes to different positions of the first curved mirror; a third reflection part that includes a plurality of reflection planes that reflect the light fluxes divided by the second reflection part and reflected by the first curved mirror; and a fourth reflection part that includes a plurality of reflection planes that reflect light from the third reflection part. The number of reflection planes of each of the third reflection part and the fourth reflection part on which the light from the first curved mirror is incident is the same as the number of divisions of the light flux by the second reflection part, and each of the light fluxes reflected by the first curved mirror is reflected by the third reflection part and the fourth reflection part to form an image, and an image of the divided object plane is formed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an optical system and an area spectroscopic device.

Background Art

[0002] When analyzing dynamic phenomena in detail, it is very useful to obtain wavelength (energy) information by spectroscopically analyzing an image simultaneously and over time, which is important in all fields involving chemical reactions. In order to spectroscopically analyze two-dimensional image information simultaneously, since a general detector is two-dimensional or less, the dimension in which wavelength information is developed increases, so it is necessary to convert a two-dimensional image into one dimension. Therefore, an area splitting optical system is an important element in area spectroscopy, which is performed in a batch at almost the same time.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Dividing the original image into smaller parts allows for the acquisition of higher-resolution information, but arranging the divided images in a one-dimensional space is not easy. One simple method is to lay out a large number of optical fibers in the image area and rearrange them in a one-dimensional manner by utilizing their flexibility. This is an excellent method that allows for higher resolution by increasing the number of fine optical fibers. However, the transmittance of optical fibers is not perfectly uniform, and the polarization state of light changes due to bending, making it difficult to extract the original optical information in a uniform state. Also, optical fibers generally consist of a core that transmits light and a cladding that causes total internal reflection, and there is an optimal size depending on the wavelength being transmitted, so there is no optical fiber that is optimal for a wide range of wavelengths, and efficiently performing surface spectroscopy across a wide wavelength band is difficult in principle. In contrast to this, a method is known in which the image is spatially divided by multiple mirrors and rearranged in a one-dimensional manner. Although there is a slight change in optical properties due to the reflection characteristics of the mirrors, it is stable and information restoration is easy. However, because each mirror needs to be positioned with extreme precision both in terms of position and angle, the number of divisions is limited to around several dozen, taking into account adjustments and manufacturing processes. This results in a spatially large system, making it difficult to incorporate a similar number of divisions into general-purpose equipment. Furthermore, surface division optics are also effective when performing image observation with a one-dimensional detector that is inexpensive, high-resolution, and offers high-speed readout, instead of using a two-dimensional detector.

[0005] Therefore, the present invention aims to provide a surface spectrometer that is advantageous for miniaturization, high resolution, or high efficiency. [Means for solving the problem]

[0006] An optical system, as one aspect of the present invention that solves the above problems, is an optical system for dividing a light beam, comprising: a first curved mirror provided with an opening for allowing a light beam from an object surface to pass through or a transmissive portion for transmitting the light beam; a second reflecting portion having a plurality of reflecting surfaces that divide the light beam from the opening or transmissive portion of the first curved mirror, and reflecting each light beam divided by each reflecting surface to different positions on the first curved mirror; a third reflecting portion having a plurality of reflecting surfaces that each reflect the light beam divided by the second reflecting portion and reflected by the first curved mirror; and a fourth reflecting portion having a plurality of reflecting surfaces that reflect light from the third reflecting portion, wherein the number of reflecting surfaces in the third reflecting portion and the fourth reflecting portion to which light from the first curved mirror is incident is the same as the number of divisions of the light beam by the second reflecting portion, and each light beam reflected by the first curved mirror is reflected by the third reflecting portion and the fourth reflecting portion to form an image, thereby forming an image of the divided object surface. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a surface spectrometer that is advantageous for miniaturization, high resolution, or high efficiency. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing the optical system of the first embodiment. [Figure 2] This diagram shows the configuration of the second reflecting section. [Figure 3] This is a diagram of the optical system of the first embodiment, viewed from the first reflecting section side. [Figure 4] This is an overhead view of the optical system of the first embodiment. [Figure 5] This is a diagram showing the configuration of the third reflecting section. [Figure 6] This figure shows the optical system of the second embodiment. [Figure 7] This is a schematic diagram of a surface spectrometer. [Modes for carrying out the invention]

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0010] [First Embodiment] Figure 1 shows a diagram of the surface-splitting optical system 100 of the first embodiment. The surface-splitting optical system 100 is an optical system that splits a light beam from the side of the object surface. As shown in Figure 1, the surface-splitting optical system 100 is composed of roughly four groups of mirrors in order from the incident direction of the incident light beam to be split. The surface-splitting optical system 100 has a first reflector 1, a second reflector 2, a third reflector 3, and a fourth reflector 4.

[0011] The first reflective section 1 is a curved mirror with a curved reflective surface, and is provided with an opening that allows light beams from the object surface to pass through or a transmitting section 1a that transmits light. For example, the opening is a cavity, and the transmitting section is made of a transparent optical material. The first reflective section 1 is, for example, a rotationally symmetric concave mirror.

[0012] The second reflecting section 2 has a plurality of reflective surfaces (mirrors) 2a that reflect the light beam from the opening or transmitting section 1a of the first reflecting section 1 in different directions depending on their respective positions. In other words, each reflective surface divides the incident light into individual light beams by reflecting the incident light to different positions on the reflective surfaces of the first reflecting section 1. Each reflective surface of the second reflecting section 2 is a rectangular mirror that is arranged without gaps in the image plane of the incident light.

[0013] Figure 2 shows the configuration of the second reflective section 2. The second reflective section 2 is supported by a support frame, as shown in Figure 2(a). Figure 2(b) is a front view of the second reflective section 2, where multiple reflective surfaces 2a appear as a single unit when viewed from the front. Figure 2(c) is an oblique view of the second reflective section 2, where each of the multiple reflective surfaces 2a faces in a different direction from the others.

[0014] Each reflecting surface of the second reflecting portion 2 reflects all the incident light beams that are split in different directions, and then they are reflected by the first reflecting portion 1. At that time, since each reflecting surface of the rectangle distributes the split light isotropically, as shown in FIG. 3, the reflected light that is isotropically split hits the reflecting surface of the first reflecting portion 1. In the first reflecting portion 1, light hits the positions indicated by circles in FIG. 3. That is, the light beams split by the second reflecting portion enter the regions divided by the two axes 1b and 1c perpendicular to the axis of rotational symmetry of the first reflecting portion 1.

[0015] The center of the second reflecting portion is arranged on the optical axis passing through the opening or transmitting portion 1a of the first reflecting portion 1. Also, the plurality of mirrors (reflecting surfaces) of the third reflecting portion 3 and the fourth reflecting portion 4 are arranged around the optical axis of the first reflecting portion 1 as the central axis. That is, the central axes of the first reflecting portion 1, the second reflecting portion 2, the third reflecting portion 3, and the fourth reflecting portion 4 are arranged coaxially. By configuring the optical system 100 in such a way, it is possible to utilize the isotropic space axially with respect to the incident light beam spatially, and miniaturization can be achieved.

[0016] The third reflecting portion 3 is a mirror group having a plurality of mirrors (reflecting surfaces) 3a, and reflects the light reflected by the second reflecting portion 2 and the first reflecting portion 1. The number of mirrors 3a of the third reflecting portion where the light from the first reflecting portion 1 enters is the same as the number of splits of the light beam by the second reflecting portion 2.

[0017] The fourth reflecting portion is a mirror group having a plurality of mirrors (reflecting surfaces) 4a, and reflects the light from the third reflecting portion 3. The number of mirrors 4a of the fourth reflecting portion 3 where the light from the first reflecting portion 1 enters is the same as the number of mirrors 3a of the third reflecting portion 3. Each mirror 4a of the fourth reflecting portion 4 is a curved mirror. An image that is condensed by each mirror 4a of the fourth reflecting portion 4 and arranged one-dimensionally (linearly) is formed in the re-imaging area. That is, each light beam reflected by the first reflecting portion 1 is reflected by the third reflecting portion 3 and the fourth reflecting portion 4 to form an image, and an image of the divided object surface is formed at the re-imaging position 5 of a predetermined surface.

[0018] Each mirror of the third reflection part 3 is flat, and each mirror of the fourth reflection part 4 is spherical, but the reverse may also be true. That is, one of the mirrors of the third reflection part and the fourth reflection part is flat, and the other is a curved surface. Each mirror of the second reflection part 2, the third reflection part 3, and the fourth reflection part 4 faces in a different direction.

[0019] Fig. 4 shows a top view of the optical system 100 and shows the optical paths reflected by each reflection part. The first reflection part 1 has an opening provided at the central part, and each mirror is arranged so that the light split by the second reflection part does not overlap with the mirrors of the third reflection part 3 and the fourth reflection part 4 respectively. The second reflection part 2 is an integrally molded arrangement so as to fill the image surface part of the incident light.

[0020] Fig. 5 shows the configuration of the third reflection part 3. Each mirror 3a of the third reflection part 3 is formed on a physically integral structure, but an opening 3b is provided in the part through which the light beam passes. Similarly, the fourth reflection part 4 is also formed on a physically integral structure, but an opening is provided in the part through which the light beam passes.

[0021] In addition, the first reflection part 1, the second reflection part 2, the third reflection part 3, and the fourth reflection part 4 have an isotropic structure centered on the incident light beam axis. By simply arranging them at a desired interval, there is no adjustment mechanism at all, and a surface spectroscopic optical system can be easily assembled.

[0022] [[ID=1V6]]As is clear from the light beam flight cross-sectional view of Fig. 1, the space is used as densely as possible to rearrange the image, and by suppressing the flight distance of the space and the mirror configuration, it is possible to achieve a small size and high efficiency with high resolution while enabling surface division.

[0023] 〔Second Embodiment〕 In this embodiment, compared with the first embodiment, the relative positions of the second mirror group 2 and the third mirror group 3 are different. Fig. 6 shows the optical system 200 of this embodiment. As shown in Fig. 6, the third reflection part 3 is arranged in front of the second reflection part 2 (on the side of the first reflection part). As a result, the third reflection part 3 is arranged near the front and rear of the second reflection part 2, and it is possible to form the second reflection part 2 and the third reflection part 3 on an integral structure.

[0024] [Third Embodiment] Next, a surface spectrometer using the optical system of the above embodiment will be described.

[0025] Figure 7 shows a schematic diagram of the surface spectrometer 500. The surface spectrometer 500 directs the light beam to be spectrally analyzed into the optical system 501 of the above embodiment, rearranges it into one dimension by surface division, and then performs surface spectroscopy through the imaging mirror 502, spectroscopic element 503, and detection unit 504. The light to be spectrally analyzed is, for example, infrared light.

[0026] In the surface spectrometer 500, the imaging mirror 502, which is an off-axis parabolic mirror, is used from the surface division optical system 501 to reflect light to a spectroscopic element 503 such as a diffraction grating. The light beam, which has been spectrally separated by the spectroscopic element 503 and spread out on the surface, is diffracted and enters the parabolic mirror again, forming an image on the detection unit 504 which has a two-dimensional detector. As a result, the spectrally separated image plane can be obtained.

[0027] To obtain the original image for each wavelength, the one-dimensional images of the desired wavelengths on the two-dimensional detector can be rearranged according to a division rule to obtain a spectral image in the form of the original image.

[0028] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its essence.

Claims

1. An optical system for splitting a beam of light, A first curved mirror is provided with an opening that allows a light beam from the surface of an object to pass through or a transparent portion that transmits the light beam, A second reflective section having a plurality of reflective surfaces that divide the light beam from the opening or the transmissive portion of the first curved mirror, and reflecting each light beam divided by each reflective surface to different positions on the first curved mirror, A third reflective section is divided by the second reflective section and has a plurality of reflective surfaces that each reflect the light beam reflected by the first curved mirror, It has a fourth reflective section having a plurality of reflective surfaces that reflect light from the third reflective section, The number of reflective surfaces in the third and fourth reflectors, to which light from the first curved mirror enters, is the same as the number of divisions of the light beam by the second reflector. An optical system characterized in that each light beam reflected by the first curved mirror is reflected by the third and fourth reflecting sections to form an image, thereby forming an image of the divided object surface.

2. The optical system according to claim 1, characterized in that the central axes of the first curved mirror, the second reflecting portion, the third reflecting portion, and the fourth reflecting portion are arranged coaxially.

3. The optical system according to claim 1, characterized in that the shape of each reflective surface of the second reflective portion is rectangular.

4. The first curved mirror is a rotationally symmetric concave mirror, The optical system according to claim 1, characterized in that the light beam divided by the second reflecting part is incident on each region divided by two axes perpendicular to the axis of rotational symmetry in the first curved mirror.

5. The optical system according to claim 1, characterized in that one of the reflective surfaces of the third reflective portion and the fourth reflective portion is a flat surface and the other is a curved surface.

6. The optical system according to claim 1, characterized in that at least one of the second reflective portion, the third reflective portion, and the fourth reflective portion integrally constitutes each reflective surface.

7. The optical system according to claim 1, characterized in that each light beam reflected by the first curved mirror is reflected by the third and fourth reflecting sections to form an image in which each divided image is linearly arranged in a predetermined direction.

8. The optical system according to claim 1, A spectroscopic element that spectrally separates light from the optical system, A surface spectrometer characterized by having a detection unit for detecting light spectrally separated by the spectroscopic element.

9. The surface spectrometer according to claim 8, characterized by spectrally separating infrared light.

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