JP2022030836A - Optical element, light detection device and fluorescence detector - Google Patents

Abstract

To provide an optical element capable of selectively transmitting light coming at an incidence angle of 10° or less when light enters the optical element at various incidence angles, and a light detection device and a fluorescence detector including such optical element.SOLUTION: An optical element 10 comprises an optical member 4 including a first surface 4a, a second surface 4b facing the first surface 4a in a predetermined direction, and a plurality of open holes 4A each extending along the directions. Each open hole 4A includes a first opening R1 located in the first surface 4a, a second opening R2 located in the second surface 4b, and an optical decay area 41 formed on a peripheral surface 4c between the first surface 4a and the second surface 4b. When greater one of a maximum width of a first area and a maximum width of a second area is denoted by a, and a distance between the first opening R1 and the second opening R2 is denoted by b, each of the plurality of open holes 4A satisfies 90°-tan-1(b/a)≤10°.SELECTED DRAWING: Figure 3

Description

The present invention relates to an optical element, a photodetector, and a fluorescence detector.

Patent Document 1 describes the fluorescence emitted from the sample between the sample and the detector and the filter for the excitation light source that selectively passes the excitation light emitted from the excitation light source between the excitation light source and the sample. A food condition evaluation device including a filter for a detector that selectively passes the light source is described. The food condition evaluation device described in Patent Document 1 further includes a polarizing plate arranged between the filter for an excitation light source and the sample, and a polarizing plate arranged between the sample and the filter for a detector. .. The pair of polarizing plates are arranged so that the direction of the transmission axis of one polarizing plate is perpendicular to the direction of the transmission axis of the other polarizing plate. As a result, even if the wavelength of fluorescence is close to the wavelength of the excitation light and the excitation light is not completely blocked by the detector filter alone, the excitation light is blocked by the pair of polarizing plates and emitted from the sample. The resulting fluorescence is incident on the detector.

Japanese Unexamined Patent Publication No. 2001-208745

By the way, as an optical filter that selectively passes light within a predetermined wavelength range, a filter including a dielectric multilayer film may be used. In an optical filter including a dielectric multilayer film, if the incident angle of light incident on the dielectric multilayer film is large, light outside a predetermined wavelength range may pass through the dielectric multilayer film. Therefore, in order for the optical filter including the dielectric multilayer film to function properly, it is necessary to reduce the incident angle of the light incident on the dielectric multilayer film.

The present invention comprises an optical element capable of selectively passing light incident at an incident angle of 10 ° or less when light is incident at various incident angles, and a photodetector including such an optical element. It is an object of the present invention to provide a fluorescence detection device.

The optical element of the present invention includes a first surface, a second surface facing the first surface in a predetermined direction, and an optical member each having a plurality of light passing portions extending along the above direction. Each of the light passing portions of is a first region located on the first surface, a second region located on the second surface, and a light attenuation region formed on the peripheral surface between the first surface and the second surface. When the maximum width of the first region and the maximum width of the second region is a, and the distance between the first region and the second region is b, each of the plurality of light passing portions is 90 °. -Tan ^-1 (b / a) ≤ 10 ° is satisfied.

In this optical element, each of the plurality of light passing portions is configured to satisfy 90 ° -tan ^-1 (b / a) ≤ 10 °, and a light attenuation region is formed on the peripheral surface of each of the plurality of light passing portions. Is formed. As a result, even when either the first region or the second region functions as the light incident region in each of the plurality of light passing portions, the light incident on the light passing portion at an incident angle exceeding 10 ° hits the peripheral surface. It becomes easy to be attenuated, and the light incident on the light passing portion at an incident angle of 10 ° or less easily passes through the light passing portion without hitting the peripheral surface (that is, without being attenuated). Therefore, according to this optical element, when light is incident at various angles of incidence, the light incident at an incident angle of 10 ° or less can be selectively passed.

In the optical element of the present invention, the light attenuation region may be formed so as to have a ring shape when viewed from the above direction. According to this, the light incident on the light passing portion can be more reliably attenuated at an incident angle exceeding 10 °.

In the optical element of the present invention, the light attenuation region may be formed so as to be continuous in an annular shape on the peripheral surface. According to this, the light incident on the light passing portion can be more reliably attenuated at an incident angle exceeding 10 °.

In the optical element of the present invention, the light attenuation region may be formed over the entire peripheral surface. According to this, the light incident on the light passing portion can be more reliably attenuated at an incident angle exceeding 10 °.

In the optical element of the present invention, each of the plurality of light passing portions is a through hole extending along the above direction, the first region is a first opening located on the first surface, and the second region is. , It may be a second opening located on the second surface. According to this, the structure of the optical member can be simplified.

In the optical element of the present invention, the light attenuation region may include an uneven region. According to this, it is possible to reliably attenuate the light incident on the light passing portion at an incident angle exceeding 10 ° while simplifying the structure of the light attenuation region.

In the optical element of the present invention, the uneven region includes a plurality of convex portions, the height of each of the plurality of convex portions is c, and the maximum wavelength of the light incident on the light passing portion is λ. (2π × (c / 2)) / λ ≧ 1 may be satisfied. According to this, when light is incident on the uneven region, scattering is likely to occur, so that the light incident on the light passing portion can be more reliably attenuated at an incident angle exceeding 10 °.

In the optical element of the present invention, the uneven region includes a plurality of convex portions including the convex portions adjacent to each other in the above direction, and the width of each of the plurality of convex portions is the maximum width of the first region and the maximum width of the second region. The distance between adjacent convex portions may be smaller than each of the maximum width of the first region and the maximum width of the second region. According to this, it is possible to suppress the specular reflection of the light incident on the light passing portion at an incident angle of more than 10 ° on the peripheral surface, so that the light can be attenuated more reliably.

In the optical element of the present invention, light within a predetermined wavelength range is selected from the light incident on one side or the other side of the optical member in the above direction and incident at an incident angle of 10 ° or less with respect to the above direction. An optical filter may be further provided. For example, when an optical filter is arranged in front of an optical member on an optical path, when light within a predetermined wavelength range and light outside a predetermined wavelength range are incident on the optical filter at various incident angles, the predetermined wavelength is used. Light within the range is likely to be incident on the optical member at an incident angle of 10 ° or less, and light outside the predetermined wavelength range is likely to be incident on the optical member at an incident angle of more than 10 °. At this time, in the optical member, the light incident at an incident angle of 10 ° or less is selectively passed, and as a result, the light within the predetermined wavelength range and the light outside the predetermined wavelength range are within the predetermined wavelength range. Light can be extracted. Further, for example, when an optical filter is arranged after the optical member on the optical path, when light within a predetermined wavelength range and light outside the predetermined wavelength range are incident on the optical member at various incident angles, the predetermined value is obtained. Light within the wavelength range and light outside the predetermined wavelength range are likely to be incident on the optical filter at an incident angle of 10 ° or less. At this time, the optical filter selectively passes light within a predetermined wavelength range among the light incident at an incident angle of 10 ° or less, and as a result, light within a predetermined wavelength range and light within a predetermined wavelength range. Light within a predetermined wavelength range can be extracted from outside light.

The photodetector of the present invention includes the above optical element and a photodetector that detects light that has passed through the optical element.

According to this photodetector, it is possible to selectively detect light incident at an incident angle of 10 ° or less.

In the optical detection device of the present invention, the optical element further includes an optical filter that selectively passes light within a predetermined wavelength range among the light incident at an incident angle of 10 ° or less with respect to the above direction, and is an optical filter. May be arranged on one side or the other side of the optical member in the above direction. According to this, light within a predetermined wavelength range can be selectively detected.

In the optical element and photodetector of the present invention, the optical filter may include a dielectric multilayer film. According to this, it is possible to realize the selective passage of light within a predetermined wavelength range with high accuracy.

The fluorescence detection device of the present invention includes the light detection device and a light source that emits excitation light for irradiating the sample, and the optical element is arranged on an optical path between the sample and the light detector. The light detection device detects the fluorescence emitted from the sample via the optical element, the excitation light is light outside a predetermined wavelength range, and the fluorescence is light within a predetermined wavelength range.

Since this fluorescence detection device includes the above optical element, it is possible to selectively detect fluorescence even when excitation light and fluorescence are incident on the optical element.

According to the present invention, an optical element capable of selectively passing light incident at an incident angle of 10 ° or less when light is incident at various incident angles, and a photodetector provided with such an optical element. It becomes possible to provide an apparatus and a fluorescence detection apparatus.

It is a block diagram of the fluorescence detection apparatus of one Embodiment. It is sectional drawing of a part of the optical member shown in FIG. It is a schematic cross-sectional view of the through hole shown in FIG. It is a block diagram of the fluorescence detection apparatus of a modification. It is a block diagram of the fluorescence detection apparatus of a modification. It is a block diagram of the fluorescence detection apparatus of a modification. It is sectional drawing of a part of the optical member of a modification. It is a schematic cross-sectional view of the through hole of a modification. It is a schematic cross-sectional view of the through hole of a modification. It is a schematic cross-sectional view of the through hole of a modification. It is a schematic cross-sectional view of the through hole of a modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.
[Configuration of fluorescence detection device]

As shown in FIG. 1, the fluorescence detection device 1 includes a light source 2 and a light detection device 3. The fluorescence detection device 1 measures the fluorescence intensity by irradiating the sample S with the excitation light EL emitted from the light source 2 and receiving the fluorescence FL emitted from the sample S by the light detection device 3. As a result, the fluorescence detection device 1 measures the concentration of the substance in the sample S.

The light source 2 emits an excitation light EL for irradiating the sample S. The light source 2 is composed of, for example, an LED or the like. The light source 2 irradiates the sample S with the excitation light EL. Sample S is, for example, a transparent aquarium containing seawater containing phytoplankton.

The photodetector 3 is arranged so as to face the sample S in a direction orthogonal to (crossing) the optical path from the light source 2 to the sample S. The photodetector 3 receives the fluorescent FL emitted from the sample S by irradiating the sample S with the excitation light EL. In the following description, the direction in which the sample S and the light detection device 3 face each other is the Z direction (predetermined direction), one horizontal direction perpendicular to the Z direction is the X direction, and the Z direction and the direction perpendicular to the X direction are described. It is called the Y direction.

The photodetector 3 includes an optical element 10, a photodetector 6, and a package 7. The photodetector 6 is arranged so as to face the sample S in the Z direction. The optical element 10 is arranged on the optical path between the sample S and the photodetector 6 (between the sample S and the photodetector 6 in the Z direction).

The entire optical element 10 and a part of the photodetector 6 (a part of the light receiving portion 61 and each lead pin 62 described later) are arranged in the package 7. The package 7 is, for example, a cylindrical member. The package 7 has a light receiving surface 7a on the side opposite to the photodetector 6 with the optical element 10 sandwiched in the Z direction. As an example, in the package 7, the portion of the light receiving surface 7a is made of transparent glass, and the other part is made of metal. The light receiving surface 7a of the package 7, the optical element 10 and the photodetector 6 arranged in the package 7 are arranged so as to face the sample S in the Z direction.

The photodetector 6 receives the fluorescent FL emitted from the sample S by being irradiated with the excitation light EL. The photodetector 6 includes a light receiving unit 61 and a plurality of lead pins 62. The light receiving unit 61 is sensitive to the excitation light EL and the fluorescence FL. The light receiving unit 61 is, for example, a silicon photodiode. The plurality of lead pins 62 penetrate the package 7 while maintaining electrical insulation and airtightness with the package 7. The plurality of lead pins 62 are connected to a signal processing circuit (not shown). As a result, the light receiving unit 61 and the signal processing circuit are electrically connected. When the light receiving unit 61 receives light, the light receiving unit 61 generates a current corresponding to the amount of light incident on the light receiving surface, and the signal processing circuit converts the current generated by the photodetector 6 into a voltage to the outside. Output.

The optical element 10 selectively passes light within a predetermined wavelength range when light L is incident at various incident angles. The light L is light traveling from the sample S side to the photodetector 6 side, and includes the excitation light EL and the fluorescent FL. Of the light L, the fluorescent FL is light within a predetermined wavelength range. The light within a predetermined wavelength range is light in a wavelength range including the wavelength to be measured by the fluorescence detection device 1. That is, the fluorescent FL is light that should be incident on the light receiving unit 61 of the photodetector 6. On the other hand, the excitation light EL is light outside a predetermined wavelength range. That is, the excitation light EL is light that should not be incident on the light receiving unit 61 of the photodetector 6. The optical element 10 includes an optical member 4 and an optical filter 5.

The optical member 4 is arranged in the package 7 so as to be adjacent to the light receiving surface 7a. The optical member 4 selectively passes the light L incident at an incident angle of 10 ° or less when the light L is incident at various incident angles. "Selectively passing the light L incident at an incident angle of 10 ° or less" means that 90% or more of the light L incident at an incident angle of 10 ° or less is passed and the light L incident at an incident angle of more than 10 ° is incident. It means that the light L is blocked by 90% or more. Specifically, the excitation light EL and the fluorescence FL are incident on the optical member 4 at various angles of incidence. The optical member 4 selectively passes the excitation light EL and the fluorescence FL incident at an incident angle of 10 ° or less among the excitation light EL and the fluorescence FL.

The optical member 4 contains a light absorbing material. In the present embodiment, the optical member 4 is made of a constituent material containing a light absorbing material or a constituent material colored by the light absorbing material. Examples of the constituent materials include resins such as acrylic, PLA, ABS, epoxy, nylon, polycarbonate and polypropylene, elastic materials such as silicon rubber, polyacetal, gypsum, and metal. The optical member 4 may be formed by painting a member made of a material different from the light absorbing material with a paint containing a natural material such as regolith. The optical member 4 has, for example, a disk shape. The diameter of the optical member 4 is, for example, 20 mm, and the thickness of the optical member 4 is, for example, 10 mm. Details of the optical member 4 will be described later.

The optical filter 5 is arranged on the optical path between the optical member 4 and the photodetector 6 (between the optical member 4 and the photodetector 6 in the Z direction). The optical filter 5 does not allow the fluorescent FL from the light L incident at an incident angle of 10 ° or less with respect to the Z direction to pass through the light in the wavelength range lower than the predetermined wavelength range (the wavelength characteristic shifts to a short wavelength). Pass selectively (without doing). That is, the optical element 10 selectively passes the fluorescent FL incident at an incident angle of 10 ° or less by including the optical member 4 and the optical filter 5.

In the present embodiment, the optical filter 5 includes a light transmitting member 51 and a dielectric multilayer film 52. As an example, the light transmitting member 51 is formed of a light transmitting material such as silicon or glass, and has a disk shape, for example. The dielectric multilayer film 52 is formed on the surface of the light transmitting member 51. Examples of the dielectric multilayer film 52 include a multilayer film composed of a combination of a high refraction material such as TiO ₂ and Ta ₂ O ₅ and a low refraction material such as SiO ₂ and Mg F ₂ . The optical filter 5 selectively passes the fluorescent FL from the light L incident at an incident angle of 10 ° or less by including the dielectric multilayer film 52.
[Structure of optical member]

As shown in FIG. 2, the optical member 4 has a first surface 4a, a second surface 4b facing the first surface 4a in the Z direction, and a plurality of through holes (plural light passing portions) 4A. There is. In the optical member 4, one of the first surface 4a and the second surface 4b functions as a light incident surface by being arranged so as to face the sample S in the Z direction, and the other of the first surface 4a and the second surface 4b. However, it functions as a light emitting surface. In the present embodiment, the first surface 4a arranged so as to face the sample S in the Z direction functions as a light incident surface, and the second surface 4b functions as a light emitting surface.

The plurality of through holes 4A are arranged in a plane triangular lattice pattern, for example, when viewed from the Z direction. The arrangement of the plurality of through holes 4A is not limited to this, and may be arranged in a square grid pattern, for example. Each through hole 4A extends along the Z direction. The plurality of through holes 4A have, for example, a columnar shape. The shape of each through hole 4A is not limited to this, and may be, for example, a hexagonal shape.

FIG. 3 is a schematic cross-sectional view of one through hole 4A. As shown in FIGS. 2 and 3, each through hole 4A includes a first opening (first region) R1, a second opening (second region) R2, and a light attenuation region 41. The first opening R1 is located on the first surface 4a. The second opening R2 is located on the second surface 4b. In the present embodiment, the size of the first opening R1 is equal to the size of the second opening R2.

In the optical member 4, one of the first opening R1 and the second opening R2 functions as a light incident region, and the other of the first opening R1 and the second opening R2 functions as a light emitting region. In the present embodiment, the first opening R1 functions as a light incident region, and the second opening R2 functions as a light emitting region.

The light attenuation region 41 is formed on the peripheral surface 4c between the first surface 4a and the second surface 4b. The light attenuation region 41 includes the uneven region 42. In the present embodiment, the uneven region 42 is formed so as to be continuous in an annular shape on the peripheral surface 4c and over the entire peripheral surface 4c. The uneven region 42 includes a plurality of convex portions 42a.

The plurality of convex portions 42a extend in the Z direction and are arranged so as to line up from the first surface 4a to the second surface 4b. The plurality of convex portions 42a are adjacent to each other in the Z direction. As a result, a space is provided between the convex portions 42a adjacent to each other in the Z direction. In the present embodiment, the convex portions 42a have the same shape and are arranged at equal intervals in the Z direction.

Each convex portion 42a is formed so as to project toward the center of the through hole 4A when viewed from the Z direction. Each convex portion 42a is formed so as to be continuous in an annular shape on the peripheral surface 4c. In other words, each convex portion 42a exhibits an annular shape when viewed from the Z direction. The cross section of each convex portion 42a seen from the X direction has a square shape. As an example, the cross section of each convex portion 42a seen from the X direction has a rectangular shape, and each convex portion 42a includes a planar top portion.

Assuming that the larger width of the maximum width of the first opening R1 and the maximum width of the second opening R2 is a and the distance between the first opening R1 and the second opening R2 is b, each through hole 4A is 90 ° -tan. ^-1 (b / a) ≦ 10 ° is satisfied. In the present embodiment, the size of the first opening R1 is equal to the size of the second opening R2. Therefore, in the present embodiment, the maximum width of the first opening R1 and the maximum width of the second opening R2 are both the width a. The distance b is the length of the through hole 4A in the Z direction.

Further, assuming that the height of each convex portion 42a is c and the maximum wavelength of the light L incident on the through hole 4A is λ, the uneven region 42 satisfies (2π × (c / 2)) / λ ≧ 1. There is. The height c of each convex portion 42a is the length from the peripheral surface 4c to the top of each convex portion 42a along the direction toward the center of the through hole 4A, based on the peripheral surface 4c of the through hole 4A. be.

The width d of each convex portion 42a is smaller than the maximum width (width a) of the first opening R1 and the maximum width (width a) of the second opening R2. The width d is the width of each convex portion 42a in the Z direction. Further, the distance e between the adjacent convex portions 42a is smaller than the maximum width of the first opening R1 and the maximum width of the second opening R2, respectively. The distance e is the distance between adjacent convex portions 42a in the Z direction.

The optical member 4 is composed of a combination of a plurality of thin plates (not shown). Each lamella has a first surface, a second surface facing the first surface, and a plurality of holes. Each thin plate has a disk shape. Each thin plate has the same shape. Each hole in each sheet extends along the thickness direction of the sheet. Each hole includes a first opening located on the first surface and a second opening located on the second surface. Each hole has a shape widened on at least one side of the first opening and the second opening. As an example, each hole has a stepwise widened shape on one side of the first opening and the second opening. The optical member 4 is formed by fixing the plurality of thin plates having the plurality of holes formed to each other so as to be laminated.

The optical member 4 may be configured by combining a plurality of thin plates including a first thin plate and a second thin plate having different shapes from each other. Each of the first thin plate and the second thin plate has a first surface, a second surface facing the first surface, and a plurality of holes, similarly to each of the above-mentioned thin plates. Each hole of the first thin plate is provided concentrically with each hole of the second thin plate. The width of each hole in the first thin plate is smaller than the width of each hole in the second thin plate. The optical member 4 is formed by fixing a plurality of thin plates in which such first thin plates and second thin plates are alternately combined one by one to each other so as to be laminated.
[Operation of fluorescence detection device]

An example of the operation of the fluorescence detection device 1 configured as described above will be described. First, when the excitation light EL is emitted from the light source 2 along the Y direction, the emitted excitation light EL irradiates the sample S. Then, the fluorescent FL is emitted from the sample S irradiated with the excitation light EL. The light L including the excitation light EL and the fluorescent FL is incident on the optical member 4 at various angles of incidence. Then, the excitation light EL and the fluorescent FL incident at an incident angle of 10 ° or less are selectively passed by the optical member 4 and incident on the optical filter 5. Then, the fluorescent FL is selectively passed among the excited light EL and the fluorescent FL incident on the optical filter 5 at an incident angle of 10 ° or less. As a result, the fluorescent FL is incident on the light receiving surface of the light receiving unit 61. Then, the light receiving unit 61 generates a current corresponding to the amount of light of the fluorescent FL incident on the light receiving surface, and a signal processing circuit (not shown) electrically connected to the light receiving unit 61 is generated by the light receiving unit 61. Converts current to voltage and outputs it. In this way, the fluorescence detection device 1 measures the fluorescence intensity of the fluorescence FL to be detected.
[Action and effect]

In the optical element 10, each through hole 4A is configured to satisfy 90 ° -tan ^-1 (b / a) ≤ 10 °, and a light attenuation region 41 is formed on the peripheral surface 4c of each through hole 4A. There is. As a result, when either the first opening R1 or the second opening R2 functions as the light incident region in each through hole 4A, the light L incident on the through hole 4A at an incident angle exceeding 10 ° is the peripheral surface 4c. The light L incident on the through hole 4A at an incident angle of 10 ° or less is likely to pass through the through hole 4A without hitting the peripheral surface 4c (that is, without being attenuated). Therefore, according to the optical element 10, when the light L is incident at various angles of incidence, the light L incident at an incident angle of 10 ° or less can be selectively passed.

In particular, in the optical element 10, the light L incident on the optical element 10 passes through each through hole 4A extending along the Z direction, and the first opening R1 is located on the first surface 4a. The second opening R2 is located on the surface 4b. Thereby, the structure of the optical member 4 can be simplified.

In the optical element 10, the light attenuation region 41 is formed so as to be continuous in an annular shape on the peripheral surface 4c. As a result, the light L incident on the through hole 4A at an incident angle exceeding 10 ° can be more reliably attenuated.

In the optical element 10, the light attenuation region 41 is formed over the entire peripheral surface 4c. As a result, the light L incident on the through hole 4A at an incident angle exceeding 10 ° can be more reliably attenuated.

In the optical element 10, the light attenuation region 41 includes the uneven region 42. This makes it possible to reliably attenuate the light L incident on the through hole 4A at an incident angle exceeding 10 ° while simplifying the structure of the light attenuation region 41. In addition, it is possible to facilitate the manufacture of the light attenuation region 41.

In the optical element 10, if the concave-convex region 42 includes a plurality of convex portions 42a, the height of each of the plurality of convex portions 42a is c, and the maximum wavelength of the light L incident on the through hole 4A is λ, the concave-convex region 42 satisfies (2π × (c / 2)) / λ ≧ 1. As a result, when the light L is incident on the uneven region 42, scattering is likely to occur, so that the light L incident on the through hole 4A can be more reliably attenuated at an incident angle exceeding 10 °.

In the optical element 10, the uneven region 42 includes a plurality of convex portions 42a including the convex portions 42a adjacent to each other in the Z direction, and the widths of the plurality of convex portions 42a are the maximum width of the first opening R1 and the second opening. It is smaller than each of the maximum widths of R2, and the distance between the adjacent convex portions 42a is smaller than the maximum width of the first opening R1 and the maximum width of the second opening R2, respectively. As a result, it is possible to suppress the specular reflection of the light L incident on the through hole 4A at an incident angle of more than 10 ° on the peripheral surface 4c, so that the light L can be attenuated more reliably.

In the optical element 10, the fluorescent FL is selectively selected from the light L (that is, the excitation light EL and the fluorescent FL) that are arranged after the optical member 4 in the Z direction and are incident at an incident angle of 10 ° or less with respect to the Z direction. It is provided with an optical filter 5 that allows the light to pass through. As a result, when the excitation light EL and the fluorescent FL are incident on the optical member 4 at various incident angles, the excitation light EL and the fluorescent FL are likely to be incident on the optical filter 5 at an incident angle of 10 ° or less. At this time, in the optical filter 5, the fluorescent FL is selectively passed out of the excited light EL and the fluorescent FL incident at an incident angle of 10 ° or less, and as a result, the fluorescent FL is extracted from the excited light EL and the fluorescent FL. can do. Further, the photodetector 3 having the optical element 10 can selectively detect the fluorescent FL even when the excitation light EL and the fluorescent FL are incident on the optical element 10.

The optical filter 5 includes a dielectric multilayer film 52. As a result, selective passage of light L within a predetermined wavelength range can be realized with high accuracy.

Here, the effect of the optical element 10 configured by combining the optical filter 5 including the dielectric multilayer film 52 and the optical member 4 will be described in detail. As a premise in fluorescence measurement, the difference between the wavelength peak of the excitation light and the wavelength peak of a general fluorescent dye is generally only about 20 nm, and the wavelength peak of the excitation light and the wavelength peak of fluorescence are close to each other. ing. Therefore, an optical filter having good wavelength separation characteristics and capable of transmitting fluorescence including the wavelength to be measured and blocking excitation light according to the characteristics of the fluorescent dye is required.

As a filter capable of arbitrarily designing the characteristics of the transmitted light and the blocking wavelength, an optical filter including a dielectric multilayer film can be mentioned. However, a filter containing a dielectric multilayer film has a property that when light is incident at an incident angle exceeding 10 °, light in a wavelength range lower than a predetermined wavelength range is passed (wavelength characteristics are shifted to a shorter wavelength). , It is difficult to eliminate this property. Therefore, it is desirable that light is incident on the optical filter at an incident angle of 10 ° or less.

Therefore, for example, it is conceivable to arrange an optical lens between the sample and the optical filter on the optical path. The optical lens passes light incident on the surface of the optical lens at an incident angle perpendicular to the surface of the optical lens, and blocks other light (light incident on the surface of the optical lens from an oblique direction). However, depending on the optical lens, it is difficult to block all the light incident on the surface of the optical lens at an angle. Further, when an optical lens is used, there is a problem that it is difficult to reduce the size and the cost is high. In particular, when a conventional fluorescence detection device is used in a microscope, when excitation light incident on the surface of the optical lens from an oblique direction passes through the optical lens, it is diffusely reflected by the lens barrel of the microscope and incident on the optical filter. It ends up. As a result, the excitation light may pass through the optical filter and enter the photodetector.

Therefore, in the fluorescence measurement, it is conceivable to use an absorption type optical filter that does not depend on the incident angle of light instead of the optical lens. By using an absorption-type optical filter, it is possible to reduce the size as compared with the case of using an optical lens, but the absorption-type optical filter uses the principle of dye absorption. Therefore, it is difficult to transmit fluorescence and block excitation light according to the characteristics of the fluorescent dye. Further, in many absorption-type optical filters, since the optical filter itself has fluorescence, there is a possibility that it may lead to erroneous detection of fluorescence different from the fluorescence emitted from the sample. Further, it is conceivable to use a fiber optic plate instead of the optical lens. However, the fiber optic plate allows light incident at an incident angle of 10 ° or more to pass through, and cannot extract only light incident at an incident angle of 10 ° or less. Therefore, fiber optic plates are also unsuitable for fluorescence measurements.

On the other hand, in the optical element 10, first, even if the excitation light EL and the fluorescent FL are incident on the optical member 4 at various incident angles, the excitation light EL and the fluorescent FL incident at an incident angle of 10 ° or less are optical. It is selectively passed from the member 4. As a result, the optical filter 5 can satisfactorily block the fluorescence that is the background of the excitation light EL, and extract only the fluorescence FL from the optical element 10. In particular, when the fluorescence detection device 1 is used in a microscope, the fluorescence FL can be detected efficiently, so that the excitation light EL can be weakened for measurement as compared with the conventional case. As a result, the damage caused by the excitation light EL to the sample S can be reduced. Further, since the optical element 10 can efficiently detect the fluorescent FL, for example, when the sample S is contained in a container for virus inspection or the like, the scattering of light L in the container gives the detection of the fluorescent FL. The impact can be reduced.

The optical element 10 is configured by combining a plurality of thin plates. As a result, the optical element 10 can be manufactured at low cost and in a small size.

In the fluorescence detection device 1, the optical element 10 is arranged on the optical path between the sample S and the light detector 6, and the light detection device 3 uses the fluorescent FL emitted from the sample S as the optical element 10. The excitation light EL detected via the light EL is light outside the predetermined wavelength range, and the fluorescent FL is light within the predetermined wavelength range.

Since the fluorescence detection device 1 includes the optical element 10, the fluorescence FL can be selectively detected even when the excitation light EL and the fluorescence FL are incident on the optical element 10.
[Modification example]

The present invention is not limited to the embodiments described above. For example, in the above embodiment, the optical member 4 has a plurality of through holes 4A, but the optical member 4 may have a plurality of light passing portions. In that case, the light passing portion may include a first region and a second region. The first region may be located on the first surface 4a, and the second region may be located on the second surface 4b as a light incident region. In the optical member 4, one of the first region and the second region may function as a light incident region, and the other of the first region and the second region may function as a light emitting region. Examples of the light passing portion include, for example, a light transmitting medium.

In the optical element 10, the optical filter 5 may be arranged on one side or the other side of the optical member 4 in the Z direction, and may be arranged in front of the optical member 4 on the optical path, for example. In the example shown in FIG. 4, the photodetector 3 has a photodetector 6, an optical element 10, and a package 7. The optical filter 5 is arranged on the optical path between the sample S and the photodetector 6 (between the sample S and the photodetector 6 in the Z direction). That is, in the example shown in FIG. 4, the optical filter 5 is arranged outside the photodetector 3 (specifically, the front stage of the photodetector 6).

According to the fluorescence detection device 1 according to this modification, when the excitation light EL and the fluorescence FL are incident on the optical filter 5 at various incident angles, the fluorescence FL is likely to be incident on the optical member 4 at an incident angle of 10 ° or less. , The excitation light EL tends to be incident on the optical member 4 at an incident angle exceeding 10 °. At this time, since the fluorescent FL incident at an incident angle of 10 ° or less is selectively passed through the optical member 4, the fluorescent FL can be extracted from the excitation light EL and the fluorescent FL also by this modification. Further, the photodetector 3 of this modification can selectively detect the fluorescent FL incident at an incident angle of 10 ° or less. Further, according to the fluorescence detection device 1 according to the present modification, since the optical filter 5 is provided separately from the light detection device 3, the optical filter 5 can be easily replaced.

The fluorescence detection device 1 may further include an optical lens 8. In the example shown in FIG. 5, the photodetector 3 has a photodetector 9 in place of the photodetector 6 and further has an optical lens 8, which is shown in FIG. Different from the example. The photodetector 9 includes a light receiving unit 91 and a plurality of lead pins 92. The area of the light receiving surface of the photodetector 9 is smaller than the area of the light receiving surface of the photodetector 6 of the above embodiment. The optical lens 8 is arranged on the optical path between the optical member 4 and the photodetector 9 (between the optical member 4 and the photodetector 9 in the Z direction). The convex surface of the optical lens 8 faces the photodetector 9. According to the fluorescence detection device 1 according to this modification, the fluorescence FL is likely to be incident on the optical lens 8 at an incident angle of 10 ° or less. At this time, the fluorescent FL is focused by the optical lens 8 toward the vicinity of the apex of the convex portion 42a of the optical lens 8. As a result, the fluorescent FL that has passed through the optical lens 8 is likely to be incident on the photodetector 9. Therefore, according to the fluorescence detection device 1 of this modification, the fluorescence FL can be selectively detected even when the photodetector 9 including the light receiving surface having a small area is provided.

Further, the example shown in FIG. 6 differs from the example shown in FIG. 4 in that the fluorescence detection device 1 further includes an optical lens 8. The optical lens 8 is arranged on the optical path between the sample S and the optical filter 5 (between the sample S and the optical filter 5 in the Z direction). The convex surface of the optical lens 8 faces the sample S. According to the fluorescence detection device 1 according to this modification, even when the fluorescence emitted from the sample S is weak (the bright spot of the fluorescence is small) due to irradiation with the excitation light EL, for example, the optical lens 8 appropriately The light L spread and parallelized is likely to be incident on the optical filter 5 and the light detection device 3. Therefore, according to the fluorescence detection device 1 of this modification, the fluorescence FL can be selectively detected even when the fluorescence FL emitted from the sample S is weak.

The maximum width of the first region may be different from the maximum width of the second region. In that case, the width a is the larger of the maximum width of the first region and the maximum width of the second region. The width d of each convex portion 42a may be larger than the maximum width of the first opening R1 and the maximum width of the second opening R2, respectively. Further, the distance e between the adjacent convex portions 42a may be larger than the maximum width of the first opening R1 and the maximum width of the second opening R2, respectively.

In the above embodiment, the cross section of each convex portion 42a has a rectangular shape, and each convex portion 42a includes a planar top portion, but the shape of each convex portion 42a is not limited to this. In the example shown in FIG. 7, the cross section of each convex portion 42a seen from the X direction is triangular, and a corner portion is formed at the top of each convex portion 42a. The optical member 4 including such an uneven region 42 may be composed of a combination of a plurality of thin plates as described below. Each sheet has a first surface, a second surface, and a plurality of holes, similar to each sheet of the above embodiment. Each hole has a shape widened on both sides of the first opening and the second opening. As an example, each hole has a shape gradually widened on both sides of the first opening and the second opening with respect to the center of the thin plate in the thickness direction. The optical member 4 is formed by fixing the plurality of thin plates having the plurality of holes formed to each other so as to be laminated.

Further, each convex portion 42a does not have to have the same shape. In the example shown in FIG. 8, adjacent convex portions 42a have different shapes from each other. Specifically, the cross section of each convex portion 42a seen from the X direction is triangular, and a corner portion is formed at the top of each convex portion 42a. Further, in the uneven region 42, the heights of the convex portions 42a adjacent to each other in the Z direction are different from each other. Further, in the example shown in FIG. 9, the cross section of each convex portion 42a seen from the X direction has a smooth shape without corners (a shape in which the inclination of the tangent line continuously changes at each point of the convex portion 42a). ).

Further, the uneven region 42 may include a plurality of protrusion-shaped protrusions 42a formed between the plurality of grooves, or may include a plurality of wall-shaped protrusions 42a. .. Further, the plurality of convex portions 42a may be formed in a regular pattern or may be formed in an irregular pattern.

The light attenuation region 41 is not limited to the uneven region 42, and may be any region that attenuates the light L. The light attenuation region 41 may be, for example, a planar region made of a light absorbing material. Further, the light attenuation region 41 different from the uneven region 42 may be formed so as to be continuous in an annular shape on the peripheral surface 4c and over the entire area of the peripheral surface 4c.

Further, the light attenuation region 41 may not be formed over the entire peripheral surface 4c, or may not be formed so as to be continuous in an annular shape on the peripheral surface 4c. In the example shown in FIG. 10, the uneven region 42 included in the light attenuation region 41 is formed over a part of the peripheral surface 4c. Specifically, the uneven region 42 is formed one on the first opening R1 side and one on the second opening R2 side in the Z direction. Further, in the example shown in FIG. 11, the uneven region 42 included in the light attenuation region 41 is formed near the center of the through hole 4A in the Z direction. In the example shown in FIG. 10 and the example shown in FIG. 11, the uneven region 42 is formed so as to be continuous in an annular shape on the peripheral surface 4c, for example. The light attenuation region 41 may be formed so as not to be continuous in an annular shape on the peripheral surface 4c and to have a ring shape when viewed from the Z direction. For example, the uneven region 42 included in the light attenuation region 41 is formed so as not to have an end portion in the circumferential direction (so as not to be continuous in an annular shape) in the example shown in FIG. 10 and the example shown in FIG. You may. This also makes it possible to more reliably attenuate the excitation light EL incident on the through hole 4A at an incident angle exceeding 10 °.

The optical member 4 may be arranged at a position different from that of the above embodiment. For example, the optical member 4 may be arranged on the optical path between the light source 2 and the sample S (between the light source 2 and the sample S in the Y direction).

The optical filter 5 may be a light absorption type filter. Further, the photodetector 6 may be a photomultiplier tube.

1 ... fluorescence detection device, 2 ... light source, 3 ... light detection device, 4 ... optical member, 4a ... first surface, 4A ... through hole (light passing portion), 4b ... second surface, 4c ... peripheral surface, 5 ... Optical filter, 6, 9 ... Optical detector, 10 ... Optical element, 41 ... Light attenuation region, 42 ... Concavo-convex region, 42a ... Convex portion, 52 ... Dielectric multilayer film, EL ... Excitation light, FL ... Fluorescence, L ... Light, R1 ... 1st opening (1st region), R2 ... 2nd opening (2nd region), S ... sample.

Claims (14)

It comprises an optical member having a first surface, a second surface facing the first surface in a predetermined direction, and a plurality of light passages each extending along the direction.
Each of the plurality of light passing portions is formed on a first region located on the first surface, a second region located on the second surface, and a peripheral surface between the first surface and the second surface. Includes the formed light attenuation region
Assuming that the larger width of the maximum width of the first region and the maximum width of the second region is a and the distance between the first region and the second region is b, each of the plurality of light passing portions is An optical element satisfying 90 ° -tan ^-1 (b / a) ≤ 10 °. The optical element according to claim 1, wherein the light attenuation region is formed so as to have a ring shape when viewed from the direction. The optical element according to claim 1 or 2, wherein the light attenuation region is formed so as to be continuous in an annular shape on the peripheral surface. The optical element according to any one of claims 1 to 3, wherein the light attenuation region is formed over the entire peripheral surface. Each of the plurality of light passing portions is a through hole extending along the above-mentioned direction.
The first region is a first opening located on the first surface.
The optical element according to any one of claims 1 to 4, wherein the second region is a second opening located on the second surface. The optical element according to any one of claims 1 to 5, wherein the light attenuation region includes an uneven region. The uneven region includes a plurality of convex portions and includes a plurality of convex portions.
Assuming that the height of each of the plurality of convex portions is c and the maximum wavelength of the light incident on the light passing portion is λ, the uneven region satisfies (2π × (c / 2)) / λ ≧ 1. The optical element according to claim 6. The uneven region includes a plurality of convex portions including adjacent convex portions in the direction.
The width of each of the plurality of convex portions is smaller than the maximum width of the first region and the maximum width of the second region, respectively.
The optical element according to claim 6 or 7, wherein the distance between the adjacent convex portions is smaller than the maximum width of the first region and the maximum width of the second region, respectively. An optical filter arranged on one side or the other side of the optical member in the above direction and selectively passing light within a predetermined wavelength range among the light incident at an incident angle of 10 ° or less with respect to the direction. The optical element according to any one of claims 1 to 8, further comprising. The optical element according to claim 9, wherein the optical filter includes a dielectric multilayer film. The optical element according to any one of claims 1 to 8.
A photodetector comprising a photodetector that detects light that has passed through the optical element. The optical element further includes an optical filter that selectively passes light within a predetermined wavelength range among light incident at an incident angle of 10 ° or less with respect to the direction.
The photodetector according to claim 11, wherein the optical filter is arranged on one side or the other side of the optical member in the direction. The photodetector according to claim 12, wherein the optical filter includes a dielectric multilayer film. The photodetector according to claim 12 or 13,
It is equipped with a light source that emits excitation light for irradiating the sample.
The optical element is arranged on an optical path between the sample and the photodetector.
The photodetector detects the fluorescence emitted from the sample via the optical element.
The excitation light is light outside the predetermined wavelength range, and is
The fluorescence is a light within the predetermined wavelength range, which is a fluorescence detection device.

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