JP4931685B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus for imaging a sample carrier accommodated in a concave portion of a container for a container in which a plurality of concave portions are formed, such as a microplate.

  Conventionally, in the fields of biochemistry and molecular biology, imaging apparatuses using fluorescent dyes as labeling substances are known. According to such an imaging device, by reading image information relating to a sample in which a specific biological substance labeled with a fluorescent dye is distributed, the gene sequence, the expression level of the gene, Absorption / excretion pathways / states, protein separation / identification, molecular weight, characteristics evaluation, etc. can be performed.

  FIG. 11 shows a conventional imaging apparatus for imaging cells in each well (11) for a microplate (1) in which a plurality of wells (11) are formed (see, for example, Patent Document 1). . As shown in the figure, a field lens (3) is installed on the optical axis S so as to oppose the surface of the microplate (1) to make the photographing optical system an object side telecentric. As the field lens (3), a Fresnel lens is adopted, and thereby the field lens (3) is thinned.

As indicated by the alternate long and short dash line in FIG. 11, the principal ray has an oblique angle with respect to the optical axis S between the photographing lens (26) of the camera (2) and the field lens (3). Between the field lens (3) and the microplate (1), parallel rays are formed by the action of the field lens (3), and the wall surface is projected to the bottom of the well (11) of the microplate (1). It is possible to shoot without being involved.
JP 2000-74837 A

  However, in the conventional photographing apparatus, since the Fresnel lens used as the field lens (3) has a large number of grooves, the groove causes deterioration of the photographed image. In this deteriorated image, Although it was possible to measure the intensity of light emitted from the cells in the well (11) of the microplate (1), there was a problem that it was not possible to accurately measure the shape characteristics such as the growth state of the cells. .

  SUMMARY OF THE INVENTION An object of the present invention is to provide an imaging apparatus including an object side telecentric optical system that can perform imaging with higher image quality than before.

An imaging device according to the present invention is intended to image a sample carrier accommodated in a plurality of recesses, targeting a container having a plurality of recesses formed on a surface thereof, and is installed facing the surface of the container. A field lens to be used, the field lens having an imaging optical system as an object side telecentric lens, which is configured by arranging a plurality of lens elements on a plane orthogonal to the optical axis, and adjacent to each other. A boundary between elements faces a partition portion extending between adjacent concave portions of the container on a line parallel to the optical axis.
Here, when the container is a microplate, a well in which cells are to be accommodated corresponds to the recess. Moreover, the partition part between recessed parts means the surface area | region of the partition wall formed with a certain width between recessed parts.

  In general, in an imaging apparatus having a field lens for making an imaging optical system object-side telecentric, a boundary between elements of a plurality of lens elements constituting a field lens, that is, a Fresnel lens passes through edge portions of a plurality of grooves. Although the light beam causes deterioration of the image quality, in the photographing apparatus according to the present invention, the boundary between the lens elements causing the deterioration of the image is a partition between the concave portions adjacent to each other of the container to be photographed, and Opposing on a line parallel to the optical axis, image degradation occurs in the image of the partition of the container. Therefore, if the image of the partition part is removed from the entire photographed image of the container and only the image of the concave part is cut out, not only the luminance of the image of the sample carrier in the concave part but also the shape feature thereof can be accurately determined based on the image. Can be measured.

In a specific configuration, the field lens is an integrally molded product including the plurality of lens elements.
In this specific configuration, the field lens is manufactured by integral molding of resin or the like.

In another specific configuration, the field lens is configured by combining the plurality of lens elements with each other as independent components. Here, for example, the plurality of lens elements are bonded to each other or are held together by a lattice-shaped holder.
In this specific configuration, a plurality of lens elements can be made of resin or optical glass, respectively, and then these lens elements can be combined with each other to form a field lens, thereby reducing the manufacturing cost. I can do it.

In another specific configuration, the field lens is configured by omitting one lens element intersecting the optical axis among the plurality of lens elements.
In the specific configuration, since the central portion of the field lens is an area that does not require telecentric correction, there is no problem that the lens element in the central portion of the field lens is missing, and thus the weight can be reduced. .

  According to the photographing apparatus according to the present invention, the size and shape of the plurality of lens elements constituting the field lens are designed in accordance with the position of the partition portion of the container to be photographed, so that photographing can be performed with higher image quality than before. It is possible to do this so that the geometrical characteristics of the sample carrier in the container can be measured accurately.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
As shown in FIG. 1, the imaging apparatus according to the present invention is intended to image cells contained in a plurality of wells (11) for a microplate (1) having a plurality of wells (11) formed on the surface. In the optical path from the camera (2) to the microplate (1), a field lens (4) in the form of a Fresnel lens is installed facing the surface of the microplate (1), thereby the object side telecentricity. An optical system is configured.

The microplate (1) is made of a colorless and transparent plastic material such as polystyrene, for example. Specifically, as shown in FIGS. 2 and 3, 12 wells (11) are arranged in 4 rows and 3 columns. is there.
On the other hand, the field lens (4) is composed of nine lens elements (41) to (41) arranged in 3 rows and 3 columns, and this gives the same function as the Fresnel lens, and the focal length is For example, it is set to 300 mm.

  In the field lens (4), an edge (42) formed at a boundary between adjacent lens elements (41) and (41) is formed between adjacent wells (11) and (11) of the microplate (1). The surface area of the partition wall (12) faces the line parallel to the optical axis S. Then, one lens element (41) at the center of the field lens (4) is opposed to the two wells (11) and (11) at the center of the microplate (1) over the entire surface, and the field lens (4) The surrounding ten lens elements (41) to (41) are opposed to the eight wells (11) to (11) around the microplate (1) on the entire surface.

  Here, the field lens (4) can be configured as an integrally molded product including nine lens elements (41) to (41). However, as shown in FIG. 41) can be manufactured as independent parts, and these lens elements (41) to (41) can be bonded to each other and combined as shown in FIG.

In the photographing apparatus, as shown in FIG. 1, the microplate (1) is photographed by the camera (2) through the field lens (4), thereby obtaining an image subjected to object side telecentric correction. That is, as indicated by the alternate long and short dash line in the figure, the image of each well (11) of the microplate (1) is captured via each lens element (41) of the field lens (4), and the well (11) The picture will be taken to the bottom.
However, since the image of the partition wall (12) of the microplate (1) is captured through the region including the edge (42) of the field lens (4), it is caused by light refraction and scattering generated at the edge (42). , The image is unclear.

However, among the images photographed by the camera (2), the image of the partition wall (12) of the microplate (1) is unnecessary for observation of the cells on the microplate (1). Therefore, the image of the partition wall (12) is removed from the image photographed by the camera (2), and only the image of the well (11) is cut out for observation.
As a result, a clear image is obtained in which the influence of the edge (42) of the field lens (4) is eliminated, and not only the brightness of the cell image on the microplate (1) but also the shape characteristics of the cell are accurately determined. Can be measured.

  In the photographing apparatus according to the present invention, when the field lens (4) is manufactured as an integrally molded product of resin (for example, acrylic), the edge (42) between the lens elements (41) and (41) is the cell as described above. Since it does not contribute to the measurement of shape characteristics, it is not always necessary to form the edge (42) on the wall surface parallel to the optical axis, and it is also possible to form it on a slope considering the draft (draft angle) at the time of resin molding. .

When the field lens (4) is composed of nine independent lens elements (41) to (41), these lens elements (41) to (41) are arranged in a lattice-shaped holder (5) as shown in FIG. It is also possible to attach to and integrate, and to delete one central lens element (41).
In addition, when each lens element is held by a grid-like holder (5) as shown in FIG. 6, refracted light and scattered light generated at the edge (42) of the field lens (4) are reflected on the frame of the holder (5). Since the light is shielded at the portion and unnecessary light is removed, an effect of improving the S / N ratio of the captured image can be obtained.
If the field lens (4) is composed of a plurality of independent lens elements (41) to (41) in this way, each lens element (41) can be formed from a convex lens piece having no step, which reduces the manufacturing cost. Reduction is possible.
Further, by forming an opening having a shape similar to that of the well (11) of the microplate (1) in the lattice holder (5), the opening exerts the function of the field stop, and the other part of the microplate (1). Unnecessary light from the light source can be actively blocked, thereby improving the S / N ratio.

Further, according to the configuration in which one lens element (41) at the center of the field lens (4) is omitted, the field lens (4) can be reduced in weight. In this way, even if one central lens element (41) is omitted, the central portion of the field lens (4) is an area that does not require telecentric correction, so that the measurement accuracy does not deteriorate.
Furthermore, as shown in FIG. 7, a plurality of field lenses (4) and (4) can be superposed to form an object side telecentric optical system. This facilitates correction of lens aberration. Further, an achromatic lens is constituted by a combination of a convex surface and a concave surface, which makes it possible to correct chromatic aberration in addition to correction of spherical aberration.

FIG. 8 shows an application example of the photographing apparatus according to the present invention. The camera (2) is positioned above the microplate (1) along the vertical optical axis, along with the light source (21) and the illumination lens ( 22) an excitation light filter (23), a dichroic mirror (24), and a field lens (4) are disposed, and a fluorescent filter (25) and a photographing lens (on a horizontal optical axis orthogonal to the optical axis) 26) and a photographing unit (28) comprising an image sensor (27).
The light source (21) is connected to the light source control unit (7), the photographing unit (28) is connected to the camera control unit (8), and the light source control unit (7) and the camera control unit (8) are connected to the information processing device (6). )It is connected to the.

Here, the microplate (1) has a well (11) having a depth of 11 mm, the field lens (4) is set to a focal length of 300 mm, and a height position of 0 to 30 mm above the microplate (1). Is installed.
The light source (21) of the camera (2) irradiates excitation light having a central wavelength of 470 nm that excites a fluorescent substance to generate fluorescence from above the microplate (1) toward the microplate (1). .
The cells contained in each well (11) of the microplate (1) do not have to be the same, and are labeled with, for example, a fluorescent substance that emits fluorescence upon receiving predetermined excitation light. It may contain things that are not labeled.

In the imaging apparatus, the excitation light applied to the microplate (1) irradiates the cells accommodated in each well (11) of the microplate (1). Fluoresces when irradiated with excitation light, while cells that are not labeled with a fluorescent substance do not fluoresce even when irradiated with excitation light.
The fluorescence emitted from each well (11) of the microplate (1) in this way passes through the field lens (4) and then is further refracted by the photographing lens (26) through the fluorescence filter (25). The light enters the image sensor (27), and the fluorescence is photoelectrically converted to create a video signal.

  From each well (11) of the microplate (1), reflected light of excitation light from the microplate (1) and the cell surface is also emitted and proceeds in the same way as fluorescence, but is blocked by the fluorescence filter (25). Therefore, it does not enter the image sensor (27). As a result, in the imaging device (27), only the one corresponding to the well (11) that has emitted fluorescence among all the wells (11) detects fluorescence.

  Here, each well (11) of the microplate (1) is photographed from directly above by the optical system that has been subjected to object side telecentric correction by the field lens (4). Even in the well (11) located at the end of), there is no possibility that the fluorescence emitted from the well (11) is mistaken for the fluorescence from the other well (11).

FIG. 9 shows another application example of the photographing apparatus according to the present invention. The camera (2) has a folding mirror (29), a fluorescent filter (25), and photographing on the horizontal optical axis. A photographing unit (28) composed of a lens (26) and an image sensor (27) is arranged, and a flat light source (20) emitting white light having a wavelength of 400 to 700 nm is arranged below the microplate (1). is doing.
The light source (20) is connected to the light source control unit (7), the photographing unit (28) is connected to the camera control unit (8), and the light source control unit (7) and the camera control unit (8) are connected to the information processing device (6). )It is connected to the.

  Similarly, in the photographing apparatus, the fluorescence emitted from each well (11) of the microplate (1) passes through the field lens (4) and then passes through the fluorescent filter (25) and further by the photographing lens (26). The image is refracted and incident on the image sensor (27), and the fluorescence is photoelectrically converted to create a video signal.

  In any application example of the photographing apparatus, an object-side telecentric optical system using a field lens (4) is provided to perform telecentric correction. The field lens (4) is formed into a Fresnel lens shape as described above to reduce the thickness, and the size of a plurality of lens elements constituting the field lens (4) according to the position of the partition wall of the microplate (1). The sheath shape is designed to prevent the image quality from being deteriorated by the edge (42) of the field lens (4).

  FIG. 10 shows an operation algorithm of the photographing apparatus according to the present invention. First, when the type of microplate (number of wells) is input to the apparatus in step S1, illumination by the light source is turned on in step S2. Next, in step S3, shooting by the camera is executed. Thereafter, in step S4, the illumination by the light source is turned off.

Subsequently, in step S5, the location of the well is cut out from the image taken by the camera in accordance with the type of the microplate, and in step S6, image processing measurement is performed on the brightness and shape in each well.
Finally, in step S7, the measurement result is displayed on the display, and the procedure is terminated.

In the conventional photographing apparatus, it was only possible to perform image processing measurement on the luminance in each well in step S6 shown in FIG. 10, but according to the photographing apparatus according to the present invention, the image processing on the shape is performed. The shape of the fluorescence distribution of the cells in each well can be accurately measured by the measurement.
As a result, it becomes possible to determine the growth state of the cells based on the fluorescence brightness of the cells in each well and the shape of the fluorescence distribution.

  In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. Each lens element (41) of the field lens (4) is not limited to a lens having a surface with a curved surface, but is formed into a wedge-shaped planar prism element having a surface formed on a plane having an inclination, It is also possible to constitute the field lens (4) by combining the planar prism elements. Even in this case, since the captured image itself by each planar prism element is clear, if necessary distortion correction processing such as correction of the aspect ratio is performed, it is possible to obtain an image having a clear shape characteristic of the imaging target. I can do it.

  In addition, the imaging apparatus according to the present invention can also capture an object to be imaged that emits chemiluminescence or bioluminescence that emits light without excitation by excitation light. In this case, a light source and a fluorescent filter for generating excitation light are not necessary.

It is a figure which shows the object side telecentric optical system of the imaging device which concerns on this invention. It is sectional drawing which shows the correspondence of a field lens and a microplate. It is sectional drawing of the direction orthogonal to sectional drawing of FIG. It is a figure which shows the example which used the field lens as the division | segmentation structure. It is a perspective view of a field lens. It is a perspective view which shows the other structure of a field lens. It is a perspective view which shows other structure of a field lens. It is a block diagram which shows the application example of the imaging device which concerns on this invention. It is a block diagram which shows the other application example of the imaging device which concerns on this invention. It is a flowchart which shows the operation | movement algorithm of the imaging device which concerns on this invention. It is a figure which shows the object side telecentric optical system of the conventional imaging device.

Explanation of symbols

(1) Microplate
(11) Well
(12) Partition wall
(2) Camera
(4) Field lens
(41) Lens element
(42) Edge
(5) Holder
(6) Information processing device
(7) Light source control unit
(8) Camera control unit

Claims (5)

  In an imaging apparatus for imaging a sample carrier accommodated in a plurality of recesses for a container having a plurality of recesses formed on a surface thereof, the imaging optical system is installed opposite to the surface of the container and an object side telecentric The field lens is configured by arranging a plurality of lens elements on a plane orthogonal to the optical axis, and a boundary between adjacent lens elements is between adjacent recesses of the container. An imaging apparatus, wherein the partitioning part extends opposite to a line parallel to the optical axis.   The imaging device according to claim 1, wherein the field lens is an integrally molded product including the plurality of lens elements.   The imaging device according to claim 1, wherein the field lens includes the plurality of lens elements as independent parts, and the lens elements are combined with each other.   The imaging device according to claim 3, wherein the plurality of lens elements are integrally held by a holder.   The imaging device according to any one of claims 2 to 4, wherein the field lens is configured by deleting one lens element that intersects the optical axis among the plurality of lens elements.

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