Patent Description:
In the related art, in the life science field, fluorescence reading devices, which detect fluorescence emitted from an observation object and generates and displays a fluorescence image according to this fluorescence, are widely used. For example, a fluorescence reading device described in <CIT> (corresponding to <CIT>) includes an observation object holding unit that holds an observation object, a light source that emits excitation light, a lens unit that focuses fluorescence emitted from the observation object on a detecting unit, and a detecting unit that detects the fluorescence focused by the lens unit.

In <CIT>, the observation object holding unit is a parallel flat plate that transmits excitation light and fluorescence. The observation object is placed on the observation object holding unit. The lens unit and the detecting unit are disposed in this order below the observation object holding unit. That is, the lens unit is disposed between the observation object holding unit and the detecting unit.

The lens unit includes a plurality of lens arrays. In each lens array, a plurality of columnar refractive index distribution type lenses are arranged in a line in a first direction. The lens unit has a configuration in which the plurality of lens arrays are arranged in a second direction orthogonal to the first direction. That is, the lens unit has a configuration in which the plurality of refractive index distribution type lenses are two-dimensionally arranged. Moreover, the lens unit has a lens holding part. The lens holding part is constituted of a pair of parallel flat plates, extending in the first direction, having a fluorescence shielding property, and sandwiches and holds the lens arrays. In the detecting unit, detecting elements that detect the fluorescence are two-dimensionally arranged.

In an example illustrated in <FIG> of <CIT>, the light source is disposed between the observation object holding unit and the lens unit, and more specifically, at an upper outer periphery of the lens unit, in other words, is disposed obliquely below the observation object holding unit. Since the light source equally radiates the excitation light to the entire surface of the observation object holding unit, a radiation surface of excitation light is directed to the observation object holding unit. For this reason, the excitation light is radiated toward the observation object obliquely from below the observation object holding unit. Additionally, the excitation light transmission filter, which transmits only the light within the preset wavelength range including the central wavelength of the excitation light, is integrally attached to the light source. A space for disposing the light source in which this excitation light transmission filter are integrated is provided between the observation object holding unit and the lens unit.

Since the excitation light is radiated toward the observation object obliquely from below the observation object holding unit, the excitation light is radiated to the surface of the observation object that is in contact with the observation object holding unit. Then, the fluorescence is emitted from the surface of the observation object that is irradiated with this excitation light and is in contact with the observation object holding unit. That is, in the observation object, the surface that is radiated with the excitation light and the surface from which the fluorescence is emitted is the same. For this reason, in <CIT>, the light source is provided on the same side as the lens unit or the detecting unit.

A fluorescence reading device according to the preamble of claim <NUM> is known from <CIT>. Further, <CIT> discloses a fluorescence reading device in which optical fibers transmit light from a light source and are buried in a lens holding part. The emission ends of the fibers are exposed in a radial direction of a ring-bearing.

Each refractive index distribution type lens has a relatively short focal length of, for example, <NUM>. For this reason, in a case where a distance between the lens unit and the observation object is not narrowed to a distance according to the focal length of each refractive index distribution type lens in the case of the lens unit using the refractive index distribution type lenses described in <CIT>, an image focused on the detecting unit is blurred and the image quality of a fluorescence image deteriorates.

However, as in an example of <FIG> of <CIT>, in a case where the light source is disposed between the observation object holding unit and the lens unit, a space for disposing the light source should be provided between the observation object holding unit and the lens unit. For this reason, there is a concern that the distance between the lens unit and the observation object cannot be narrowed to the distance according to the focal length of the refractive index distribution type lens, the image focused on the detecting unit is blurred, and the image quality of the fluorescence image deteriorates.

This is because, in <CIT>, the light source with which the excitation light transmission filter is integrated is used. The light source with which the excitation light transmission filter is integrated has a size of about <NUM>. For this reason, the space of at least about <NUM> is required between the observation object holding unit and the lens unit. Meanwhile, since the focal length of the refractive index distribution type lens is about <NUM>, it is physically impossible to narrow the distance between the lens unit and the observation object to the distance according to the focal length of the refractive index distribution type lens. Hence, <CIT> has room for improvements with respect to a configuration in which the excitation light is radiated.

An object of the invention is to provide a fluorescence reading device capable of narrowing a distance between a lens unit and an observation object to a distance according to a focal length of a refractive index distribution type lens and focusing fluorescence emitted from the observation object on a detecting unit without blurring.

In order to solve the above problems, a fluorescence reading device of the invention comprises the features of claim <NUM> or of claim <NUM>.

The invention includes the light guide unit that guides the excitation light emitted from the light source and radiates the guided excitation light toward the surface of the observation object that faces the lens unit. The light guide unit has smaller size and shape constraints than the light source. For this reason, by using the light guide unit, various configurations in which the distance between the lens unit and the observation object is made narrow than that in the related art in which the light source is disposed between the observation object holding unit and the lens unit. For example, in a case where the focal length of the refractive index distribution type lens is about <NUM>, the distance between the lens unit and the observation object can be reliably narrowed to about <NUM> that is the focal length of the refractive index distribution type lens. Hence, it is possible that the fluorescence reading device capable of narrowing the distance between the lens unit and the observation object to the distance according to the focal length of the refractive index distribution type lens and focusing the fluorescence emitted from the observation object on the detecting unit without blurring.

As illustrated in <FIG>, a fluorescence reading device <NUM> is a device that detects fluorescence that is excited with excitation light and emitted from an observation object S, and generates and displays a fluorescence image according to this fluorescence. The fluorescence reading device <NUM> includes an observation object holding unit <NUM>, a lens unit <NUM>, an excitation light cutoff filter <NUM>, a detecting unit <NUM>, a light source <NUM>, and an optical fiber bundle <NUM> equivalent to a light guide unit.

The observation object holding unit <NUM>, the lens unit <NUM>, the excitation light cutoff filter <NUM>, and the detecting unit <NUM> are disposed in this order in a Z-axis direction. Additionally, the respective parts <NUM> to <NUM> all have outer shapes that are parallel plate shapes, and are disposed such that upper surfaces and lower surfaces thereof become parallel to an XY plane including an X-axis and a Y-axis orthogonal to this. In addition, an X-axis direction corresponds to a first direction, and a Y-axis direction corresponds to a second direction. A Z-axis is an axis perpendicular to both the X-axis and the Y-axis.

The observation object holding unit <NUM> holds the observation object S. More specifically, the observation object holding unit <NUM> has the observation object S placed on the upper surface thereof. The observation object holding unit <NUM> is formed of materials, such as glass or resin, which allow the excitation light and the fluorescence to be transmitted therethrough.

The lens unit <NUM> is disposed between the observation object holding unit <NUM> and the excitation light cutoff filter <NUM> and further between the observation object holding unit <NUM> and the detecting unit <NUM>. The lens unit <NUM> focuses the fluorescence on the detecting unit <NUM>.

The lens unit <NUM> has a lens array <NUM>. In the lens array <NUM>, a plurality of refractive index distribution type lenses <NUM> are arranged in one row in a line in the X-axis direction that is the first direction (refer to <FIG> and the like). The lens unit <NUM> has a configuration in which a plurality of the lens arrays <NUM> are arranged in the Y-axis direction that is the second direction. That is, the lens unit <NUM> has a configuration in which the plurality of refractive index distribution type lenses <NUM> are two-dimensionally arranged in the XY plane. In addition, in the lens array <NUM>, the refractive index distribution type lenses <NUM> may be arranged in two or more rows.

Each refractive index distribution type lens <NUM> has a columnar outer shape of which the diameter is, for example, about <NUM> to <NUM>. The refractive index distribution type lens <NUM> is, specifically, a SELFOC (registered trademark) lens.

Moreover, the lens unit <NUM> has a lens holding part <NUM>. The lens holding part <NUM> is constituted of a pair of parallel flat plates extending in the X-axis direction, and sandwiches and holds the lens arrays <NUM> (refer to <FIG>). The lens arrays <NUM> adjacent to each other in the Y-axis direction are separated from each other by two lens holding parts <NUM>. The lens holding parts <NUM> are formed of, for example, black resin, and has a fluorescence shielding property.

The excitation light cutoff filter <NUM> has a spectral characteristic in which that the excitation light is not literally transmitted, and hinders incidence of the excitation light to the detecting unit <NUM>. Meanwhile, the excitation light cutoff filter <NUM> has a spectral characteristic that the fluorescence is transmitted from the observation object S. For the fluorescence image generated on the basis of the fluorescence, the excitation light becomes noise. Hence, an S/N ratio of the fluorescence image can be improved by providing the excitation light cutoff filter <NUM>.

In the detecting unit <NUM>, a plurality of detecting elements are two-dimensionally arranged. Each detecting element detects the fluorescence transmitted through the observation object holding unit <NUM>, the lens unit <NUM>, and the excitation light cutoff filter <NUM>, and outputs a detection signal. The detecting unit <NUM> has a detection plane for detecting the fluorescence on the upper surface thereof. The detecting unit <NUM> is, for example, a flat panel detector (FPD), a charge-coupled device (CCD) type detector, a complementary metal-oxide semiconductor (CMOS) type detector, or the like. The size of the detecting elements that constitute the detecting unit <NUM> is, for example, <NUM> square µm to <NUM> square µm. Additionally, although the size of the detection plane of the detecting unit <NUM> can be appropriately changed in accordance with to the size of the observation object S, the size is, for example, <NUM> square.

The light source <NUM> has a light-emitting element <NUM>, an excitation light transmission filter <NUM>, a condensing lens <NUM>, and a case <NUM>. The light-emitting element <NUM> is a light-emitting diode (LED), and emits the excitation light toward the excitation light transmission filter <NUM>. The excitation light transmission filter <NUM> has a spectral characteristic that only light of a preset wavelength range including a central wavelength of the excitation light is transmitted therethrough. That is, in the excitation light emitted from the light-emitting element <NUM>, an excessive component that may become the noise of the fluorescence image is removed by the excitation light transmission filter <NUM>. The condensing lens <NUM> condenses the excitation light transmitted through the excitation light transmission filter <NUM> toward an incident end <NUM> of the optical fiber bundle <NUM>.

The case <NUM> has a light shielding property. The case <NUM> accommodates the light-emitting element <NUM>, the excitation light transmission filter <NUM>, the condensing lens <NUM>, and the incident end <NUM> of the optical fiber bundle <NUM>.

The optical fiber bundle <NUM> guides the excitation light that is incident from the incident end <NUM>. At the incident end <NUM> of the optical fiber bundle <NUM>, a plurality of well-known optical fibers each having a core and a clad are bundled. The bundled optical fiber bundle <NUM> is wired toward the lens unit <NUM>. Then, the bundled optical fiber bundle <NUM> is subdivided into a predetermined number of optical fiber sub-bundles 20A (refer to <FIG>) in front of the lens unit <NUM>. In addition, the predetermined number is within a range of, for example, one, which is not covered by the claims, to several tens. In a case where the predetermined number is one, an optical fiber sub-bundle 20A becomes an optical fiber itself. However, in order to distinguish the optical fiber sub-bundle from the optical fiber bundle <NUM>, optical fiber sub-bundles also including one optical fiber are referred to as the optical fiber sub-bundles 20A for convenience.

As shown in <FIG> and <FIG>, the optical fiber sub-bundles 20A are buried in the lens holding parts <NUM> of the lens unit <NUM>. Specifically, the optical fiber sub-bundles 20A are fitted into attachment grooves <NUM> formed in the lens holding parts <NUM> as illustrates by arrows in <FIG>.

The attachment grooves <NUM> are formed on surfaces 27B opposite to surfaces 27A of the lens holding parts <NUM> that hold each lens array <NUM> therebetween. Each attachment groove <NUM> is formed at the same position in the two lens holding parts <NUM> separating the adjacent lens arrays <NUM> from each other. That is, the attachment groove <NUM> has a so-called half-split shape in which a cylindrical cavity for accommodating each optical fiber sub-bundle 20A is formed by the two lens holding parts <NUM> being joined to each other in the surfaces 27B.

The attachment groove <NUM> has a portion that extends parallel to the X-axis direction from an end part of each lens holding part <NUM>, and a portion that rises from a portion perpendicularly in the Z-axis direction. An end part including an emission end <NUM> of the optical fiber sub-bundle 20A is located in the portion of the attachment groove <NUM> that rises perpendicularly in the Z-axis direction. The emission end <NUM> is exposed to a surface (hereinafter, an upper surface) 27C of the lens holding part <NUM> that faces the observation object holding unit <NUM>. In addition, the attachment groove <NUM> may be raised at an obtuse angle from the portion extending parallel to the X-axis direction such that a bending load is not applied to the optical fiber sub-bundle 20A.

The excitation light from the light source <NUM> is radiated toward the observation object S of the observation object holding unit <NUM> from the emission end <NUM>. The surface of the observation object S in contact with the observation object holding unit <NUM> is irradiated with the excitation light. Then, the fluorescence is emitted from the surface of the observation object S that is irradiated with this excitation light and is in contact with the observation object holding unit <NUM>.

The attachment grooves <NUM> are formed in all the lens holding parts <NUM> other than the lens holding parts <NUM> disposed at both ends with respect to the Y-axis direction. Additionally, the portions of the attachment grooves <NUM> that rise perpendicularly in the Z-axis direction are formed at positions parallel to the Y-axis direction at equal intervals with respect to the X-axis direction. For this reason, emission ends <NUM> are disposed all the lens holding parts <NUM> other than the lens holding parts <NUM> disposed at both ends with respect to the Y-axis direction, and are disposed at equal intervals at on a straight line parallel to the X-axis direction, and is disposed at equal intervals at a straight line parallel to the Y-axis direction. Hence, it can be said that the emission ends <NUM> are equally disposed within the XY plane (the upper surfaces 27C of the lens holding parts <NUM>). In addition, the numbers of optical fiber sub-bundles 20A to be buried in the two lens holding parts <NUM> separating the adjacent lens arrays <NUM> from each other are several to several tens.

As illustrated in <FIG>, a distance H between the lower surface of the observation object holding unit <NUM> and the upper surface 27C of each lens holding part <NUM> coincides with the focal length (for example, <NUM>) of the refractive index distribution type lens <NUM>. In this state, the excitation light illustrated by one-dot chain lines is emitted at a predetermined emission angle from each emission end <NUM>, and is equally radiated to the entire lower surface of the observation object holding unit <NUM>. In other words, in a case where the distance H between the lower surface of the observation object holding unit <NUM> and the upper surface 27C of the lens holding part <NUM> is made to coincide with the focal length of each the refractive index distribution type lens <NUM>, the number and the arrangement of emission ends <NUM>, and the emission angle are set such that the excitation light is equally radiated to the entire lower surface of the observation object holding unit <NUM>.

In <FIG>, the moving mechanism <NUM> is connected to the lens unit <NUM>. The moving mechanism <NUM> moves the lens unit <NUM> in Y-axis direction. The moving mechanism <NUM> is a well-known mechanism, such as a cam, which converts a rotational motion of a motor into a translational motion. A movement controller <NUM> that controls the operation of the moving mechanism <NUM> is connected to the moving mechanism <NUM>.

Although the fluorescence from the observation object S is focused on the detecting unit <NUM> by the refractive index distribution type lenses <NUM> of the lens unit <NUM>, a portion thereof is shielded by the lens holding part <NUM> having a fluorescence shielding property and does not reach the detecting unit <NUM>. Hence, the fluorescence image has no image information of a portion corresponding to the lens holding part <NUM> as it is. Thus, the movement controller <NUM> moves the lens unit <NUM> to a plurality of positions in the Y-axis direction through the moving mechanism <NUM>.

<FIG> has illustrated a case (Φ ≥ 2W) where a diameter Φ of each refractive index distribution type lens <NUM> is equal to or more than a width 2W equivalent to two times the width W of the lens holding part <NUM> in the Y-axis direction. In this case, the movement controller <NUM> moves the lens unit <NUM> from a first position illustrated in <FIG> to a second position illustrated in <FIG> through the moving mechanism <NUM>. The second position is, specifically, a position moved by a distance of L/<NUM> in the Y-axis direction from the first position, in a case where a center-to-center distance between the adjacent lens array <NUM> is L. By doing so, each lens array <NUM> is disposed at the second position, in a portion where each lens holding part <NUM> is present at the first position. Hence, a situation where a portion of the fluorescence from the observation object S is shielded by the lens holding part <NUM> and does not reach the detecting unit <NUM> is solved.

In a case where the diameter Φ of the refractive index distribution type lens <NUM> is smaller than 2W (Φ < 2W), the movement controller <NUM> moves the lens unit <NUM> to three or more positions from the first position to the second position, from the second position to a third position, and. through the moving mechanism <NUM>. For example, in a case where the diameter Φ of the refractive index distribution type lens <NUM> is equal to W, the movement controller <NUM> moves the lens unit <NUM> from the first position to the second position and from the second position to the third position by W through the moving mechanism <NUM>.

The movement controller <NUM> moves the lens unit <NUM> to the last position through the moving mechanism <NUM> and then returns the lens unit <NUM> to the first position again.

In <FIG>, the fluorescence reading device <NUM> includes a storage unit <NUM>, a central processing unit (CPU) <NUM>, a display unit <NUM>, and an operating unit <NUM> in addition to the aforementioned detecting unit <NUM>, light source <NUM>, and moving mechanism <NUM>. The storage unit <NUM> is, for example, a hard disk drive or the like, and stores an operation program <NUM>. By starting the operation program <NUM>, the CPU <NUM> functions as a light source controller <NUM>, a detection controller <NUM>, an image generation unit <NUM>, and a display controller <NUM>, including the aforementioned movement controller <NUM>.

The light source controller <NUM> controls the operation of the light source <NUM>, specifically, ON/OFF of the light-emitting element <NUM> of the light source <NUM>. The detection controller <NUM> controls the operation of the detecting unit <NUM>, specifically, the output operation of detection signals of the fluorescence by the detecting elements of the detecting unit <NUM>. The image generation unit <NUM> generates the fluorescence image on the basis of the detection signals of the fluorescence from the detecting unit <NUM>. The display controller <NUM> outputs the fluorescence image generated by the image generation unit <NUM> to the display unit <NUM>, such as a liquid crystal display.

The detection controller <NUM> makes the detecting unit <NUM> detect the fluorescence to output the detection signals at each position of the lens unit <NUM> moved by the moving mechanism <NUM>. The image generation unit <NUM> synthesizes the detection signals detected each time at each position to generate one fluorescence image.

Alternatively, the detection controller <NUM> makes the detecting unit <NUM> expose the fluorescence continuously from a first position to the last position, to output the detection signals, without making the detecting unit <NUM> output the detection signals at each position of the lens unit <NUM> moved by the moving mechanism <NUM>. In this case, the image generation unit <NUM> generates one fluorescence image on the basis of the detection signals from the detecting unit <NUM> without carrying out the processing in which the detection signals detected each time at each position as described above are synthesized.

The operating unit <NUM> is, for example, well-known input devices, such as a keyboard and a mouse. The operating unit <NUM> is operated in a case where a startup instruction of the operation program <NUM>, an imaging instruction for the fluorescence image, or the like is input.

Next, the operation of the fluorescence reading device <NUM> having the above configuration will be described with reference to a flowchart of <FIG>. In a case where the fluorescence image is captured by the fluorescence reading device <NUM>, the observation object S is first placed on an upper surface of the observation object holding unit <NUM> (Step ST100). Next, the imaging instruction for the fluorescence image is input via the operating unit <NUM> (Step ST110).

In a case where the imaging instruction is input via the operating unit <NUM>, the excitation light is emitted from the light source <NUM> under the control of the light source controller <NUM>. The excitation light is guided by the optical fiber bundle <NUM>, and is radiated toward the observation object S from the emission ends <NUM> of the optical fiber sub-bundles 20A exposed to the upper surfaces 27C of the lens holding parts <NUM> (Step ST120).

The fluorescence is emitted from the observation object S by the radiation of the excitation light. The fluorescence is radiated by the detecting unit <NUM> via the lens unit <NUM> and the excitation light cutoff filter <NUM>. This fluorescence is detected by the detecting unit <NUM> under the control of the detection controller <NUM> (Step ST130).

Subsequently, the lens unit <NUM> is moved through the moving mechanism <NUM> under the control of the movement controller <NUM> (Step ST140). A series of processing in these steps ST120 to ST140 is continued until the lens unit <NUM> is returned to the first position (YES in Step ST150).

The detection signals based on the basis of the fluorescence at a plurality of positions including the first position are output from the detecting unit <NUM> until the lens unit <NUM> is returned to the first position. In the example illustrated in <FIG>, two detection signals based on the fluorescence at the first position and the second position are output.

After the lens unit <NUM> is returned to the first position, in the image generation unit <NUM>, one fluorescence image is generated on the basis of the plurality of detection signals at individual positions, which are output from the detecting unit <NUM> (Step ST160). The generated fluorescence image is displayed on the display unit <NUM> under the control of the display controller <NUM> (Step ST170).

In the present example, the optical fiber bundle <NUM> (optical fiber sub-bundles 20A), which guides the excitation light emitted from the light source <NUM> and radiates the guided excitation light toward the surface of the observation object S that faces the lens unit <NUM>, is provided. For this reason, it is not necessary to dispose the light source <NUM> between the observation object holding unit <NUM> and the lens unit <NUM>. That is, it is not necessary to provide a space equivalent to the light source <NUM> between the observation object holding unit <NUM> and the lens unit <NUM>. For this reason, a distance between the lens unit <NUM> and the observation object S can be narrowed to a distance according to the focal length of the refractive index distribution type lens <NUM>. Hence, it is possible to focus the fluorescence emitted from the observation object S on the detecting unit <NUM> without blurring the fluorescence, and the image quality of the fluorescence image can be excellently maintained.

The optical fiber bundle <NUM> used as the light guide unit is general as an industrial product, is relatively inexpensive, and is easily obtained. Additionally, processing, such as bundling or subdividing into the optical fiber sub-bundles 20A, can be easily performed. For this reason, there is little concern about an increase in component cost and complication and a manufacturing process.

Moreover, in the present example, the optical fiber sub-bundles 20A are buried in the lens holding parts <NUM>, and the optical fiber sub-bundles 20A are integrated with the lens holding parts <NUM> by exposing the emission ends <NUM> of the optical fiber sub-bundles 20A to the upper surfaces 27C of the lens holding parts <NUM>. For that reason, as <FIG> illustrated, the distance between the lens unit <NUM> and the observation object S can be narrowed such that the distance H between the lower surface of the observation object holding unit <NUM> and the upper surface 27C of each lens holding part <NUM> coincides with the focal length of the refractive index distribution type lens <NUM>.

Moreover, in the present example, since the emission ends <NUM> are equally disposed within the upper surface 27C of the lens holding part <NUM>, the quantity of light of the excitation light radiated to the observation object S also becomes uniform. Hence, the excitation light can be uniformly radiated to the observation object S, and a fluorescence image with more excellent image quality can be obtained.

In addition, in a case where the excitation light emitted from each emission end <NUM> has a sufficient quantity of light, the number of emission ends <NUM> to be exposed to the upper surfaces 27C of the lens holding parts <NUM> can be reduced. For example, the emission ends <NUM> may not be disposed in all the lens holding parts <NUM> other than the lens holding parts <NUM> disposed at both ends with respect to the Y-axis direction. Specifically, as illustrated in <FIG>, the emission ends <NUM> are alternately disposed in the two lens holding parts <NUM> separating the adjacent lens arrays <NUM> from each other.

Additionally, the emission ends <NUM> may not be disposed at equal intervals on the straight line parallel to the Y-axis direction. For example, as illustrated in <FIG>, the emission ends <NUM> may be disposed in a staggered lattice pattern in the two lens holding parts <NUM> separating the adjacent lens arrays <NUM> from each other. The emission ends <NUM> may also be disposed in a staggered lattice pattern with respect to the X-axis direction.

Also in the example illustrated in these <FIG> and <FIG>, there is no change in the emission ends <NUM> being equally disposed within the upper surface 27C of the lens holding part <NUM>. Hence, the effect that the excitation light can be uniformly radiated to the observation object S is obtained.

A second embodiment illustrated in <FIG> and <FIG> is an example in which the emission ends <NUM> of the optical fiber sub-bundles 20A are disposed at an outer periphery of the lens unit, and the emission ends <NUM> are directed to the observation object holding unit <NUM>.

In <FIG>, in a fluorescence reading device <NUM> of the present embodiment, a lens unit <NUM> in which the optical fiber sub-bundles 20A are not buried in lens holding parts <NUM> is used, but may also be buried in the lens holding part as in the first embodiment. The emission ends <NUM> of the optical fiber sub-bundles 20A are disposed at the outer periphery of the lens unit <NUM>. The emission ends <NUM> are directed to the observation object holding unit <NUM>. Since the other components are the same as those of the fluorescence reading device <NUM> of the above first embodiment, the description thereof will be omitted.

As illustrated in <FIG>, the emission ends <NUM> of the optical fiber sub-bundles 20A are disposed at equal intervals so as to surround the entire outer periphery of the lens unit <NUM>. Specifically, the emission ends <NUM> are lined up at the same intervals as the diameter Φ of the refractive index distribution type lens <NUM> with respect to the X-axis direction. Additionally, with respect to the Y-axis direction, the emission ends <NUM> are lined up at intervals Φ+2W obtained by summing up the diameter Φ of the refractive index distribution type lens <NUM> and the width 2W equivalent to two times the width W of each lens holding part <NUM> in the Y-axis direction. That is, the emission ends <NUM> are disposed at the same pitch as the array pitches of the refractive index distribution type lenses <NUM> in the X-axis direction and the Y-axis direction.

In this way, the emission ends <NUM> of the optical fiber sub-bundles 20A are disposed at the outer periphery of the lens unit <NUM>. Thus, it is not necessary to form the attachment grooves <NUM> for fitting the optical fiber sub-bundles 20A into the lens holding parts <NUM>, as in a case where the optical fiber sub-bundles 20A of the above first embodiment are buried in the lens holding parts <NUM> and the emission ends <NUM> are exposed to the upper surfaces 27C. Hence, compared to the above first embodiment, the labor and cost of the processing of the attachment grooves <NUM> can be reduced.

In addition, in this case, the arrangement angle of the optical fiber sub-bundles 20A with respect to the observation object holding unit <NUM> is adjusted. More specifically, the portion of the observation object holding unit <NUM> to be handled is assigned to individual optical fiber sub-bundles 20A such that a certain optical fiber sub-bundle 20A is directed toward an end part of the observation object holding unit <NUM> and a certain optical fiber sub-bundle 20A is directed toward a central part of the observation object holding unit <NUM>. Additionally, since the distance from each emission end <NUM> becomes longer at the central part the observation object holding unit <NUM> than at the end part of the observation object holding unit <NUM> and the excitation light is attenuated, the quantity of light is increased by making the number of optical fibers that constitute the optical fiber sub-bundles 20A that handle the central part larger than the number of optical fibers that constitute the optical fiber sub-bundles 20A that handle the end part. By taking such measures, the excitation light having the same quantity of light is radiated to the entire lower surface of the observation object holding unit <NUM>, and the excitation light is uniformly radiated to the observation object S.

The third embodiment illustrated in <FIG> and <FIG> is an example in which the emission ends <NUM> of the optical fiber sub-bundles 20A are disposed at the outer periphery of the lens unit <NUM>, and the emission ends <NUM> are directed not toward the observation object holding unit <NUM> but toward the upper surfaces of the lens holding parts that face the observation object holding unit <NUM>.

In <FIG>, a fluorescence reading device <NUM> of the present embodiment is the same as the above second embodiment in that a lens unit <NUM> in which the optical fiber sub-bundles 20A are not buried in lens holding parts <NUM>, and the emission ends <NUM> of the optical fiber sub-bundles 20A are disposed at the outer periphery of the lens unit <NUM>. However, the present embodiment is different from the above second embodiment in that the emission ends <NUM> are directed not toward the observation object holding unit <NUM> but toward upper surfaces 76C of the lens holding parts <NUM> that face the observation object holding unit <NUM>. Since the other components are the same as those of the fluorescence reading device <NUM> of the above first embodiment, the description thereof will be omitted.

As illustrated in <FIG>, similar to the above second embodiment, the emission ends <NUM> of the optical fiber sub-bundles 20A are disposed at equal intervals so as to surround the entire outer periphery of the lens unit <NUM>. Additionally, similar to the above second embodiment, the intervals relating to the X-axis direction and the intervals related to the Y-axis direction are also respectively the diameter Φ of the refractive index distribution type lens <NUM>, and intervals Φ+2W obtained by summing up the width 2W equivalent to two times the width W of each lens holding part <NUM> in the Y-axis direction and the diameter Φ of the refractive index distribution type lens <NUM>.

The lens holding parts <NUM> are formed of a material that reflects the excitation light. Additionally, the upper surfaces 76C of the lens holding parts <NUM> are subjected to, for example, roughening processing, such as of sandblasting, and is made into a scattering surface, as illustrated by hatching. In this case, the excitation light emitted from the emission ends <NUM> is reflected and scattered by the upper surfaces 76C of the lens holding parts <NUM>, and is radiated toward the observation object holding unit <NUM> from the upper surfaces 76C of the lens holding parts <NUM>.

Even with the above configuration, similar to the above second embodiment, the effect that the labor and cost of the processing of the attachment grooves <NUM> can be reduced compared to the above first embodiment can be obtained.

Since the upper surfaces 76C of the lens holding parts <NUM> are made into the scattering surfaces, the excitation light having more uniform quantity of light can be radiated to a wider range of the observation object holding unit <NUM>.

In addition, even in this case, similar to the above second embodiment, the arrangement angle of the optical fiber sub-bundles 20A with respect to the upper surfaces 76C of the lens holding parts <NUM> is adjusted such that the excitation light having the same quantity of light is radiated to the entire lower surface of the observation object holding unit <NUM>. Additionally, the quantity of light is increased by making the number of optical fibers that constitute the optical fiber sub-bundles 20A that handle central parts of the upper surfaces 76C of the lens holding parts <NUM> larger than the number of optical fibers that constitute the optical fiber sub-bundles 20A that handle end parts of the upper surfaces 76C.

Additionally, it is not necessary to form all the lens holding parts <NUM> of the material that reflects the excitation light, and at least the upper surfaces 76C that reflect and scatter the excitation light may have a configuration in which the excitation light is reflected. For example, it is possible to coat the upper surfaces 76C with the material that reflects the excitation light.

The fourth embodiment illustrated in <FIG> is an example in which two light guide paths formed by cavities, and a plurality of reflecting members disposed within the light guide paths constitute a light guide unit.

In <FIG>, a light guide unit <NUM> of the fourth embodiment is constituted of a first light guide path <NUM>, a second light guide path <NUM>, a plurality of beam splitters <NUM> equivalent to the reflecting members, and a total reflection mirror <NUM> that is also equivalent to a reflecting member (in <FIG> and <FIG>, the beam splitters <NUM> and the total reflection mirror <NUM> are not illustrated). The first light guide path <NUM> and the second light guide path <NUM> are cylindrical cavities formed within lens holding parts <NUM>, and allow the excitation light to pass therethrough. More specifically, the first light guide path <NUM> and the second light guide path <NUM> are formed in a half-split shape in bonding surfaces of the two lens holding parts <NUM> separating the adjacent lens arrays <NUM> from each other similar to the attachment groove <NUM> of the above first embodiment, and the cylindrical cavities are formed by the two lens holding part <NUM> being joined to each other.

The first light guide path <NUM> extends in the X-axis direction, which is the first direction, within the lens holding parts <NUM>. A plurality of the second light guide paths <NUM> are provided, and are disposed at intervals D in the X-axis direction. The plurality of second light guide paths <NUM> respectively communicate with the first light guide path <NUM> and one end of each thereof opens toward the observation object holding unit <NUM> (the observation object S is not illustrated). Additionally, the plurality of second light guide paths <NUM> are parallel to the Z-axis direction, and respectively intersect the first light guide path <NUM>, which extends in the X-axis direction, at right angles.

The beam splitters <NUM> and the total reflection mirror <NUM> are respectively disposed at intersection points between the first light guide path <NUM> and the plurality of second light guide paths <NUM>. The beam splitters <NUM> and the total reflection mirror <NUM> are disposed so as to be tilted with respect to an optical axis of the excitation light (illustrated by arrows of one-dot chain lines), which passes through the first light guide path <NUM>, at <NUM>°. The beam splitters <NUM> transmit a portion of the excitation light passing through the first light guide path <NUM>, and reflect the remainder of the excitation light toward the second light guide paths <NUM>. The total reflection mirror <NUM> is located on the most downstream side of the first light guide path <NUM>, and reflect all the excitation light passing through the first light guide path <NUM> toward the second light guide paths <NUM>.

The end of the first light guide path <NUM> on the most upstream side opposite to a side where the total reflection mirror <NUM> is disposed opens to end surfaces of the lens holding parts <NUM>. A light source <NUM> that emits the excitation light is disposed at a position that faces an opening 81A of this first light guide path <NUM>. The light source <NUM> has the light-emitting element <NUM> and the excitation light transmission filter <NUM>, similar to the light sources <NUM> (refer to <FIG> and the like) of the above embodiments. However, the light source <NUM> has a collimating lens <NUM> instead of the condensing lens <NUM>, and has a configuration in which the light-emitting element <NUM>, the excitation light transmission filter <NUM>, and the collimating lens <NUM> are accommodated in a case <NUM> having a light shielding property. The collimating lens <NUM> makes the excitation light, which is emitted from the light-emitting element <NUM> and transmitted through the excitation light transmission filter <NUM>, into collimated light, and makes the collimated light incident on the first light guide path <NUM>.

A portion of the excitation light incident on the first light guide path <NUM> is reflected by the individual beam splitters <NUM> and is incident the second light guide paths <NUM>. Additionally, the excitation light is totally reflected by the total reflection mirror <NUM>, and is incident on the second light guide paths <NUM>. The excitation light incident on the second light guide paths <NUM> is emitted from openings of the second light guide paths <NUM>, and is radiated to the lower surface of the observation object holding unit <NUM>. In addition, although illustration is omitted, the scattering plate for making excitation light collimated by the collimating lens <NUM> into scattered light are disposed in the openings of the second light guide paths <NUM>.

The intervals D of the adjacent second light guide paths <NUM> are all equal to each other. That is, the second light guide paths <NUM> are formed at equal intervals with respect to the X-axis direction. Additionally, as <FIG> illustrated, the second light guide paths <NUM> are formed in all the lens holding parts <NUM> other than the lens holding part <NUM> disposed at both ends with respect to the Y-axis direction, similar to the emission ends <NUM> illustrated in <FIG> of the above first embodiment. Moreover, the second light guide paths <NUM> are formed at equal intervals on a straight line parallel to the Y-axis direction. That is, the lens unit in this case has a configuration in which the emission ends <NUM> are substituted with the second light guide paths <NUM>, in the lens unit <NUM> illustrated in <FIG> or <FIG>. Hence, it can be said that the plurality of second light guide paths <NUM> are equally disposed within the XY plane (the upper surfaces 85C of the lens holding parts <NUM>).

As illustrated in Table <NUM> of <FIG>, the reflectivities of the beam splitters <NUM> are adjusted such that the light quantities of the excitation light that passes through the plurality of second light guide paths <NUM> become the same. Table <NUM> shows reflectivities of the individual beam splitters <NUM> in the case of the number of the reflecting members (the beam splitters <NUM> and the total reflection mirror <NUM>) (the number of the second light guide paths <NUM>) = <NUM>, and reflected light quantities and transmitted light quantities in a case where the light quantity of the excitation light that is first incident on the first light guide path <NUM> from the light source <NUM> is <NUM>. Additionally, Table <NUM> shows that, as No. is smaller, a reflecting mirror is at a position closer to the light source <NUM> side, that is, at a position closer to the upstream side of the first light guide path <NUM>.

The reflectivities increase toward the downstream side. The most downstream No. <NUM> is the total reflection mirror <NUM>, and the reflectivity thereof is <NUM>%. In the example of Table <NUM>, since the number of second light guide paths <NUM> = <NUM>, the reflectivity is adjusted such that the light quantities (reflected light quantities) of the excitation light passing through the ten second light guide paths <NUM> are the same "<NUM>".

In addition, the expression the "light quantities of the excitation light that passes through the plurality of second light guide paths <NUM> are same" includes not only completely the same but also allow some variations. In the example of Table <NUM>, although the reflected light quantities of the beam splitter <NUM> of Nos. <NUM>, <NUM>, <NUM>, and <NUM> are "<NUM>", the reflected light quantity of Nos. <NUM>, <NUM>, and <NUM> are "<NUM>", the reflected light quantity of No. <NUM> is "<NUM>", the reflected light quantities of Nos. <NUM> and <NUM> are "<NUM>", and somewhat vary from each other. However, since these reflected light quantities all become "<NUM>" in a case where the reflected light quantities are rounded off at two decimal points, it is assumed that the "light quantities of the excitation light that passes through the plurality of second light guide paths <NUM> are same". In addition, a range where the variations are allowed is, for example, a range where the reflected light quantities coincide with each other in a case where the reflected light quantities are rounded off at two decimal points. This is based on manufacturing errors of the reflecting members, such as the beam splitters <NUM> and the total reflection mirror <NUM>, being about ±<NUM>%.

In this way, since the light guide unit <NUM> is constituted of the first light guide path <NUM>, the second light guide paths <NUM>, the beam splitters <NUM>, and the total reflection mirror <NUM>, it is not necessary to prepare the optical fiber bundle <NUM> unlike the above individual embodiments. For this reason, the cost for the optical fiber bundle <NUM> can be reduced.

Since the reflectivities of the beam splitters <NUM> are adjusted such that the light quantities of the excitation light that passes through the plurality of second light guide paths <NUM> become the same and the plurality of second light guide paths <NUM> are equally disposed, the excitation light can be uniformly radiated to the observation object S.

For example, similar to the example illustrated in <FIG>, the second light guide paths <NUM> may not be disposed in all the lens holding parts <NUM> other than the lens holding parts <NUM> disposed at both ends with respect to the Y-axis direction. Additionally, similar to the example illustrated in <FIG>, the second light guide paths <NUM> may be disposed in a staggered lattice pattern in the two lens holding parts <NUM> separating the adjacent lens arrays <NUM> from each other.

Although the light source <NUM> is disposed at the position that faces the opening of the first light guide path <NUM>, in this case, it is necessary to dispose the light source <NUM> by the amount equivalent to the first light guide path <NUM>. Thus, the light source <NUM> of each of the above embodiments may be used instead of the light source <NUM>, and the emission ends <NUM> of the optical fiber sub-bundles 20A may be disposed at positions that face the opening of the first light guide path <NUM>. In this case, the optical fiber bundle <NUM> (optical fiber sub-bundles 20A) is also included in the light guide unit <NUM>.

The second light guide paths <NUM> need not be orthogonal to the first light guide path <NUM>. The second light guide paths <NUM> may intersect the first light guide path <NUM> at an acute angle or an obtuse angle.

A fifth embodiment illustrated in <FIG> is an example in which a light guide plate having a parallel plate shape constitute a light guide unit.

In <FIG>, a fluorescence reading device <NUM> of the present embodiment includes a light guide plate <NUM> having a parallel plate shape, as the light guide unit. The lens unit <NUM> of the above second embodiment is used for the lens unit. The light guide plate <NUM> is disposed between the observation object holding unit <NUM> and the lens unit <NUM>.

As illustrated in <FIG> and <FIG>, the light guide plate <NUM> has a transmission plate <NUM>, a first reflective film <NUM>, a second reflective film <NUM>, the first openings <NUM>, and second openings <NUM>. Similar to the observation object holding unit <NUM>, the transmission plate <NUM> is formed of materials, such as glass or resin, which that allows the excitation light and the fluorescence to be transmitted therethrough. The first reflective film <NUM> and the second reflective film <NUM> are any one of aluminum films, gold films, silver films, and dielectric multilayer films, and reflect the excitation light. The first reflective film <NUM> is formed on a surface (hereinafter, an upper surface) 110A of the transmission plate <NUM> that faces the observation object holding unit <NUM>. The second reflective film <NUM> is formed on a surface (hereinafter, a lower surface) 110B of the transmission plate <NUM> that faces the lens unit <NUM>.

The first openings <NUM> are portions in which the first reflective film <NUM> is missing in a slit shape on the upper surface 110A of the transmission plate <NUM>. The second openings <NUM> are portions in which the second reflective film <NUM> is missing a slit shape at positions that face the first reflective film <NUM>, on the lower surface 110B of the transmission plate <NUM>. For this reason, the first openings <NUM> and the second openings <NUM> transmit the excitation light.

The first openings <NUM> and the second openings <NUM> are formed at positions corresponding to the lens arrays <NUM>. That is, the width of each first opening <NUM> in the Y-axis direction is the same as the diameter Φ of the refractive index distribution type lens <NUM>, and the intervals of the adjacent first openings <NUM> in the Y-axis direction are the same as the width 2W equivalent to the two lens holding parts <NUM> in the Y-axis direction. The length of the first opening <NUM> in the X-axis direction is the same as the length of each lens array <NUM> in the X-axis direction. The same applies to the second openings <NUM>. In addition, in <FIG>, in order to avoid complication, only two second openings <NUM> disposed at both ends with respect to the Y-axis direction are drawn. Additionally, in <FIG>, for the same reason, only two first openings <NUM> disposed at both ends with respect to the Y-axis direction are drawn.

In this case, as illustrated by arrows of one-dot chain lines, the excitation light is incident from both side surfaces 110C and 110D on the short side of the transmission plate <NUM> parallel to the X-axis direction. In more detail, as illustrated in <FIG>,the excitation light is emitted from light sources <NUM> disposed at positions that face both the side surfaces 110C and 110D, and is incident on both the side surfaces 110C and 110D. Although only one light source <NUM> is drawn for each of both the side surfaces 110C and 110D in <FIG>, a plurality of the light sources <NUM> are arranged at equal intervals in the X-axis direction in practice. For this reason, as illustrated by one-dot chain lines illustrated in <FIG> and <FIG>, the excitation light is equally incident on both the side surfaces 110C and 110D.

Each light source <NUM> has the light-emitting element <NUM>, the excitation light transmission filter <NUM>, and the condensing lens <NUM>, similar to the light sources <NUM> (refer to <FIG> and the like) of the first to third embodiments. However, the light source <NUM> has a configuration that there is no incident end <NUM> of the optical fiber bundle <NUM> unlike the light source <NUM> and the light-emitting element <NUM>, the excitation light transmission filter <NUM>, and the condensing lens <NUM> are accommodated in a case <NUM> having a light shielding property. The distances of the light source <NUM> from both the side surfaces 110C and 110D are adjusted such that the condensing lens <NUM> is brought into a focus on both the side surfaces 110C and 110D.

As illustrated by arrows of one-dot chain lines, the light guide plate <NUM> propagates the excitation light, which is incident from the side surfaces 110C and 110D of the transmission plate <NUM>, through the inside of the transmission plate <NUM> while reflecting the excitation light with the first reflective film <NUM> and the second reflective film <NUM>, and emits a portion of excitation light, which is propagated through the inside of the transmission plate <NUM>, toward the observation object holding unit <NUM> (the observation object S is not illustrated) through the first openings <NUM>. Since the first openings <NUM> are formed in a slit shape that imitates the lens arrays <NUM>, the excitation light is also formed in a slit shape that imitates the lens arrays <NUM>, and is radiated to the observation object holding unit <NUM>. Although the excitation light is also emitted toward the lens unit <NUM> through the second openings <NUM>, since this excitation light is cut by the excitation light cutoff filter <NUM> and does not reach the detecting unit <NUM>, there is no influence on the image quality of the fluorescence image.

Additionally, a moving mechanism having the same configuration as the moving mechanism <NUM> is connected to the light guide plate <NUM>. The light guide plate <NUM> moves in synchronization with the movement of the lens unit <NUM> under the control of the movement controller <NUM> through this moving mechanism. Accordingly, the excitation light is selectively radiated to the position of the observation object holding unit <NUM> corresponding to the lens arrays <NUM>, and the fluorescence is radiated from the observation object S to which the excitation light is selectively radiated to the detecting unit <NUM>.

The light guide plate <NUM> is disposed between the observation object holding unit <NUM> and the lens unit <NUM>. For this reason, constraints for narrowing the distance between the lens unit <NUM> and the observation object S increase compared to the above first to fourth embodiments in which there is nothing present between the observation object holding unit <NUM> and the lens unit. However, since the light guide plate <NUM> has the parallel plate shape and the thickness thereof can be relatively thin as several millimeters, and there are fewer constraints for narrowing the distance between the lens unit <NUM> and the observation object S than providing the space equivalent to the light source being disposed between the observation object holding unit and the lens unit as in the related art. Hence, the distance between the lens unit <NUM> and the observation object S can be narrowed to the distance according to the focal length of the refractive index distribution type lens <NUM>, and it is possible to focus the fluorescence emitted from the observation object S on the detecting unit <NUM> without blurring.

Here, a case where a phosphor sheet including a photostimulable phosphor layer is used as the observation object S is considered. In addition, the phosphor sheet is, for example, a sheet on which a radiographic image of a subject is recorded by receiving radiation transmitted through a subject, such as a patient, and a photostimulable phosphor is excited by radiation of excitation light to emit photostimulable emission light according to the radiographic image. The phosphor sheet is also referred to as an imaging plate.

In a case where the excitation light is radiated to the entire phosphor sheet at once, for example, in a case where the lens unit is at the first position, fluorescence is emitted also from the portion of the phosphor sheet to be detected after the second position. Hence, it is impossible to detect the fluorescence after the second position.

However, according to the light guide plate <NUM>, as mentioned above, the excitation light is selectively radiated to the position of the observation object holding unit <NUM> corresponding to the lens arrays <NUM>, and the fluorescence is radiated from the observation object S to which the excitation light is selectively radiated to the detecting unit <NUM>. Hence, it is possible to avoid a situation where the excitation light is also radiated at once to portions other than the portion of the phosphor sheet corresponding to the lens arrays <NUM> and it is impossible to detect the fluorescence of the portion concerned.

Similar to the case of the above fourth embodiment, the light source <NUM> of each of the above embodiments may be used instead of the light source <NUM>, and the emission ends <NUM> of the optical fiber sub-bundles 20A may be disposed at both the side surfaces 110C and 110D. In this case, the light guide unit is constituted of the optical fiber bundle <NUM> (optical fiber sub-bundles 20A) and the light guide plate <NUM>.

In the light guide plate <NUM> illustrated to <FIG> and <FIG>, the plurality of second openings <NUM> that are the portions in which the second reflective film <NUM> are missing are formed in the lower surface 110B of the transmission plate <NUM>. However, as illustrated in <FIG>, as long as the second reflective film may have the characteristics of reflecting the excitation light transmitting the fluorescence, the second openings <NUM> may not be provided.

<FIG> illustrates a light guide plate <NUM> as seen from the lower surface side of the transmission plate. In the light guide plate <NUM>, as illustrated by dotted lines, first openings <NUM> are formed in the upper surface of the transmission plate. However, as illustrated by hatching, the second reflective film <NUM> is only formed on the whole on the lower surface of the transmission plate, and the second openings are not formed. In this case, the second reflective film <NUM> is a dielectric multilayer film that reflects the excitation light and transmits the fluorescence.

According to the light guide plate <NUM> of <FIG>, since the lower surface of the transmission plate is covered with the second reflective film <NUM> and does not have the second openings, the excitation light is not emitted toward the lens unit <NUM> from the second openings <NUM> unlike the light guide plate <NUM>, and is emitted only from the first openings <NUM>. Since the quantity of the excitation light that does not contribute to fluorescence excitation without being radiated to the observation object S becomes smaller than that in the case of the light guide plate <NUM>, the irradiation efficiency of the excitation light to the observation object S can be raised. Moreover, since the transmission of the excitation light to the lens unit <NUM> is prevented by the second reflective film <NUM>, that is, the second reflective film <NUM> plays the role of the excitation light cutoff filter <NUM>, the excitation light cutoff filter <NUM> can be omitted. Additionally, since the fluorescence is transmitted through the second reflective film <NUM> and is radiated to the detecting unit <NUM>, there is no influence on the generation of the fluorescence image.

The light guide plate has a configuration in which the excitation light incident from both the side surfaces of the transmission plate is propagated through the inside of the transmission plate and a portion of the excitation light is emitted from the first openings in the middle of the propagation. For this reason, there is concern that the light quantity of the excitation light is lower at the central part of the upper surface of the transmission plate than at the end parts of the upper surface of the transmission plate on both the side surfaces on which the excitation light is incident. Then, it is preferable to make the exclusive area of the first openings at the central part larger than that at the end parts on the upper surface of the transmission plate that faces the observation object S for the purpose of suppressing a decrease in the light quantity of the excitation light at this central part.

In a light guide plate <NUM> illustrated in <FIG>, a first reflective film <NUM> and first openings <NUM> are formed in an upper surface 131A of a transmission plate. The width of each first opening <NUM> in the Y-axis direction is the narrowest on both side surfaces 131C and 131D of the transmission plate on which the excitation light is incident. The width gradually becomes wider toward the central part, and becomes the maximum at the central part. That is, in the upper surface 131A of the transmission plate, the exclusive area of the first openings <NUM> at the central part is large rather than that at the end parts. By adopting this configuration, a decrease in the light quantity of the excitation light at the central part can be suppressed.

The first openings and the second openings may not have the slit shapes. For example, as in a light guide plate <NUM> illustrated in <FIG>, in a first reflective film <NUM> formed on an upper surface 136A of a transmission plate, circularly missing portions that imitate the shape of the refractive index distribution type lens <NUM> may be used as first openings <NUM>. The first openings <NUM> are alternately formed in portions corresponding to the refractive index distribution type lenses <NUM> with respect to the X-axis direction. In addition, in a case where the light guide plate <NUM> is used, at individual positions, such as a first position, the light guide plate <NUM> is moved in the X-axis direction by a distance equivalent to the diameter Φ of each refractive index distribution type lens <NUM>, and the fluorescence before and after the movement is detected by the detecting unit <NUM>.

In the case of the light guide plate <NUM>, simply by making the area of the first openings <NUM> larger toward the central part, the exclusive area of the first openings <NUM> at the central part can be made larger than that at the end parts, on the upper surface 136A of the transmission plate. In addition to or instead of this, the number of the first openings <NUM> may be increased toward the central part.

Claim 1:
A fluorescence reading device comprising:
an observation object holding unit (<NUM>) that holds an observation object (S) that is excited with excitation light to emit fluorescence;
a light source (<NUM>) that emits the excitation light;
a detecting unit (<NUM>) in which detecting elements for detecting the fluorescence are two-dimensionally arranged;
a lens unit (<NUM>) which is disposed between the observation object holding unit (<NUM>) and the detecting unit (<NUM>) to focus the fluorescence on the detecting unit (<NUM>), and on which a plurality of refractive index distribution type lenses are two-dimensionally arranged: and
a light guide unit (<NUM>) that guides the excitation light emitted from the light source to radiate the guided excitation light toward a surface of the observation object (S) that faces the lens unit (<NUM>), wherein the lens unit (<NUM>) is configured such that a plurality of lens arrays (<NUM>), in each of which the plurality of refractive index distribution type lenses are arranged in a line in a first direction, are arranged in a second direction orthogonal to the first direction,
the lens unit (<NUM>) further has a lens holding part (<NUM>),
the lens holding part include a plurality of pairs of parallel flat plates each sandwiching and holding a line of lens arrays (<NUM>), and each extending in a direction perpendicular to the second direction;
characterized in that
the light guide unit (<NUM>) includes a plurality of the optical fibers (<NUM>, 20A) that guide the excitation light,
the optical fibers are buried in the lens holding part, and
emission ends (<NUM>) of the optical fibers (<NUM>, 20A) are exposed to a surface of the lens holding part that faces the observation object holding unit (<NUM>).