JP2015038539A - Lens element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve light collection efficiency and detection accuracy while suppressing an increase in size.SOLUTION: A lens element includes a center part for collecting light emitted radially from a point light source by refraction, and a peripheral part for collecting the light from the point light source by reflection. The center part has an incident side convex surface (28a) having a curved shape convex outward in the optical axis direction, and an emission side convex surface (28b) having a curved shape convex outward in the optical axis direction. The peripheral part has an incident side end face (29a), an outer surface (29b) formed continuously to the incident side end face (29a) and internally reflecting light from the incident side end face (29a), and an emission side end face (29c) for emitting the light internally reflected by the outer surface (29b). At the boundary between the incident side convex surface (28a) in the center part and the incident side end face (29a) of the peripheral part, a recessed boundary part is formed.

Description

  The present invention relates to a lens element used for an objective lens or the like of a fluorescence detection apparatus that reads fluorescent labels distributed two-dimensionally.

  Conventionally, a fluorescence detection system using a fluorescent dye as a labeling substance has been widely used in the fields of biochemistry and molecular biology. By using this fluorescence detection system, it is possible to evaluate gene sequences, gene mutation / polymorphism analysis, protein separation and identification, and the like, which are used for development of drugs and the like.

  As an evaluation method using a fluorescent label as described above, a method is often used in which biological compounds such as proteins are distributed in a gel by electrophoresis and the distribution of the biological compounds is obtained by fluorescence detection. ing. In the electrophoresis, an electrode is placed in a solution such as a buffer solution, and an electric field gradient is generated in the solution by flowing a direct current. At this time, when there is a charged protein, DNA (Deoxyribonucleic acid: deoxyribonucleic acid) or RNA (ribonucleic acid: ribonucleic acid) in the solution, the positively charged molecule is the cathode, the negatively charged molecule is The biomolecules can be separated by being attracted to the anode.

  Two-dimensional electrophoresis, which is one of the evaluation methods using electrophoresis, is an evaluation method that distributes biomolecules two-dimensionally in a gel by combining two types of electrophoresis methods. Proteomic analysis It is considered the most effective way to do it.

  Examples of the combination of the electrophoresis include, for example, “isoelectric focusing using the difference in isoelectric point of each protein” as the first dimension and “SDS that performs separation based on the molecular weight of the protein” as the second dimension. -PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) "is mainly used. A fluorescent dye is applied to the protein as the biomolecule thus separated before or after electrophoresis.

  Furthermore, the gel support on which the biomolecules (proteins) prepared as described above are two-dimensionally distributed is irradiated with excitation light, and the generated fluorescence intensity is obtained, and the fluorescence distribution (protein Distribution) Image readers that display images are widely used in the fields of biochemistry and molecular biology.

  As a method for maintaining the two-dimensional distribution of the biomolecules, not only the gel is retained in the gel, but also the protein is separated from the gel and then the membrane is separated from the gel using electrophoresis or capillary action. There is also a method of transferring to the surface. In that case, as in the case of image reading using the gel support, the fluorescence distribution on the transfer support, which is the membrane, can be imaged by an image reading device.

  As an image reading device that reads a biomolecule distribution image from a gel support or transfer support in which biomolecules are two-dimensionally distributed as described above, an image disclosed in Japanese Patent Laid-Open No. 10-3134 (Patent Document 1) There is a reader.

  In the conventional image reading apparatus, a mirror having a hole in the center is mounted on an optical head moved in the main scanning direction, and a transfer support on which electrophoresis of denatured DNA labeled with a fluorescent substance is recorded is recorded. On the other hand, a laser beam (excitation light) having a wavelength corresponding to the wavelength of the fluorescent material from the light source is irradiated through the hole of the mirror. Then, the fluorescence emitted when the fluorescent dye in the transfer support is excited is reflected around the hole of the mirror, and is detected by being photoelectrically converted by a multiplier. Thus, image data for one line is stored in the line buffer. Hereinafter, by repeating the above operation while moving the optical head in the sub-scanning direction orthogonal to the main scanning direction, a two-dimensional visible image (fluorescent image) is obtained by the image processing apparatus.

  As described above, in the conventional image reading apparatus, since excitation light is irradiated to the transfer support without using a dichroic mirror, strong excitation energy is higher than that of a method in which excitation light is irradiated through a dichroic mirror. The S / N of a signal (image information) that can be applied to the transfer support and photoelectrically detected can be improved.

  However, when detecting weak fluorescence, further improvement in S / N is required.

  In order to improve the S / N of the photoelectrically detected signal (image information), the fluorescent dye is excited and emitted by irradiation with excitation light such as laser light, and is emitted in an isotropic manner. It is necessary to collect as much as possible. As described above, as a lens element capable of efficiently condensing light that is isotropically spread and emitted, a collimator lens disclosed in the republished WO2008 / 0669143 (Patent Document 2) and Japanese Patent Application Laid-Open No. 2010-114044 (Patent Document) There is an optical member disclosed in Document 3).

  In the collimator lens disclosed in Patent Document 2, as shown in FIG. 10, the entrance surface is a spherical surface, and the exit surface is a composite of a convex ellipsoid on the center side and a concave ellipsoid on the peripheral side. The side surface is a convex elliptical surface. The light beam from the light source 101 is incident on the spherical surface 102 a that is the incident surface of the collimator lens 102 substantially perpendicularly. Among them, a light beam having a small angle with the optical axis is refracted by the convex elliptical surface 102c, which is an output surface, and is emitted as a parallel light beam. In addition, a light beam having a large angle with the optical axis is totally reflected by the convex elliptical surface 102b which is the side surface and is collected at the second focal point. The light beam that is totally reflected by the ellipsoidal surface 102b and collected at the second focal point is refracted by the concave ellipsoidal surface 102d that is the emission surface, and is emitted as a parallel light beam.

  Thus, the light beam emitted from the light source 101 is converted into substantially parallel light by the collimator lens 102.

  Further, in the optical member disclosed in Patent Document 3, as shown in FIG. 11, the incident surface 106 corresponding to the light emitting portion 105 and the emission side facing the incident surface 106 are integrally formed. A cylindrical lens unit 107 and a reflecting surface 108 continuous with the incident surface 106 are provided. Then, the light emitted from the linear light emitting unit 105 and radiated at a narrow angle is condensed linearly by the cylindrical lens unit 107. Further, the light radiated at a wide angle is condensed at the focal point F of the cylindrical lens unit 107 by the total reflection of the reflection surface 108.

  As described above, in any of the collimator lens and the optical member, the light condensing rate is obtained by condensing the light beam having a large angle with the optical axis from the light source or the light emitting unit by total reflection on the side surface. It is possible to increase.

  However, the conventional collimator lens and the optical member have the following problems.

  That is, for example, in the case of the collimator lens disclosed in Patent Document 2, the entire incident surface on which the light from the light source 101 enters is composed of one spherical surface 102a. The light source 101 is located at the center of the spherical surface 102a. For this reason, the light from the light source 101 enters the spherical surface 102a substantially perpendicularly, and is uniformly incident on the entire incident surface. Therefore, the light at the central part that is incident on the spherical surface 102a that is the incident surface and reaches the convex elliptical surface 102c that is the output surface, and the convex elliptical surface that is incident on the spherical surface 102a that is the incident surface and is the total reflection surface The light in the peripheral part reaching 102b is not clearly separated.

  Therefore, there is a gap between the light ray incident on the spherical surface 102a depicted in FIG. 10 and reaching the convex elliptical surface 102c and the light ray incident on the spherical surface 102a and reaching the convex elliptical surface 102b. Thus, there is light that is totally reflected by the concave elliptical surface 102d that is the exit surface. Such light totally reflected by the elliptical surface 102d is stray light because it is not in the optical path assumed to be collected. In particular, when the collimator lens is used in a fluorescence detection apparatus, there is a problem that the fluorescence detection accuracy decreases due to the presence of the stray light.

  Furthermore, since the entire incident surface is composed of one spherical surface (concave surface) 102a, a light condensing effect on the incident surface cannot be expected. Accordingly, it is necessary to increase the condensing efficiency on the exit side accordingly, and there is a problem that design restrictions such as the need to increase the curvature of the convex elliptical surface 102c on the exit side, and the elliptical surface 102c. Therefore, when the collimator lens is used in the fluorescence detection device, there arises a problem that the fluorescence detection device is enlarged.

  The above problem also occurs in the case of the optical member disclosed in Patent Document 3. That is, the entire incident surface on which the light from the light emitting unit 105 is incident is composed of the incident surface 106 that is a single plane. Therefore, the light from the light emitting unit 105 is incident substantially uniformly on the entire incident surface. Therefore, the light at the central portion that is incident on the incident surface 106 and reaches the cylindrical lens portion 107 and the light at the peripheral portion that is incident on the incident surface 106 and reaches the reflective surface 108 are not clearly separated. For this reason, light that becomes stray light exists between the light at the central portion and the light at the peripheral portion because there is no optical path that is supposed to be condensed.

  Further, since the entire incident surface is composed of the incident surface 106 which is a single plane, a light condensing effect on the incident surface cannot be expected. Therefore, it is necessary to increase the condensing efficiency on the output side by that amount, which causes a problem of design restrictions and a problem that the fluorescence detection apparatus is enlarged.

Japanese Patent Laid-Open No. 10-3134 Republished WO2008 / 069143 JP 2010-114044 A

  Accordingly, an object of the present invention is to provide a lens element capable of increasing the light collection efficiency and the detection accuracy while suppressing an increase in size.

In order to solve the above problems, the lens element of the present invention is
A central portion for condensing the light emitted radially from the point light source by refraction;
A peripheral portion that is adjacent to the periphery of the central portion and collects the light from the point light source by reflection, and the central portion is
While the light from the point light source is incident, the incident side convex surface having a convex curved surface shape toward the outer side in the optical axis direction,
While emitting light from the incident side convex surface, and including an output side convex surface having a curved surface shape convex toward the outside in the optical axis direction,
The above peripheral part is
An incident side end surface on which light from the point light source is incident;
An outer peripheral surface for reflecting the light from the incident side end surface inside;
And an emission side end surface for emitting the light internally reflected by the outer peripheral surface,
A concave boundary is formed at the boundary between the incident-side convex surface at the central portion and the incident-side end surface at the peripheral portion.

In the lens element of one embodiment,
The incident-side convex surface in the central portion and the incident-side end surface in the peripheral portion are configured such that the optical path of light incident from the incident-side convex surface and the optical path of light incident from the incident-side end surface border the concave boundary portion. Thus, they are separated from each other and do not cross each other.

In the lens element of one embodiment,
The incident-side end surface in the peripheral portion has a curved surface shape that is convex outward.

In the lens element of one embodiment,
The outer peripheral surface in the peripheral portion has a curved surface shape that is convex outward.

In the lens element of one embodiment,
The incident side end face in the peripheral portion has a shape capable of guiding light incident from the incident side end face to the outer peripheral face so as to satisfy the total reflection condition.

  As is clear from the above, the lens element of the present invention is configured such that, in the central portion including the optical axis, the incident surface is configured with a convex incident-side convex surface, while the output surface is configured with a convex output-side convex surface. The efficiency of light collection can be easily improved. Therefore, it is not necessary to particularly increase the curvature of the exit-side convex surface on the exit side, and the focal length of the exit-side convex surface is increased and the module on which the lens element is mounted does not increase in size.

  Furthermore, a concave boundary is formed on the incident surface at the boundary between the incident-side convex surface in the central portion and the incident-side end surface in the peripheral portion. Therefore, the refractive directions of the light incident on the incident-side convex surface and the light incident on the incident-side end surface are completely different, and the central portion and the peripheral portion on the incident surface are clearly separated. Therefore, the light incident on the incident-side convex surface and the light incident on the incident-side end surface can be prevented from reaching the surface between the output-side convex surface and the outer peripheral surface. It is possible to prevent the light reaching the surface between the outer peripheral surfaces from becoming stray light.

  That is, according to the present invention, it is possible to increase the light collection efficiency and the detection accuracy while suppressing an increase in size.

It is an external view of the fluorescence detection apparatus using the lens element of this invention. It is an external view of the scanning stage installed in the lower part of the sample stand in FIG. It is sectional drawing of the scanning module mounted on the 2nd stage in FIG. It is sectional drawing of the objective lens in FIG. It is a figure which shows an example of the specific shape of the said objective lens. It is sectional drawing of the 1st lens in FIG. It is a figure which shows an example of the specific shape of the said 1st lens. FIG. 4 is a ray diagram from an objective lens to a pinhole when a sample is sealed in a two-dimensional electrophoresis substrate in FIG. 3. It is a light ray figure at the time of mounting a sample directly in FIG. It is sectional drawing in the conventional collimator lens. It is sectional drawing in the conventional optical member.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 is an external view of a fluorescence detection apparatus in which the lens element of the present embodiment is used. The fluorescence detection apparatus 1 is roughly configured by a main body 2 that forms a casing and a lid 3 that covers an upper surface of the main body 2. A sample table 4 made of glass is provided on the upper surface of the main body 2, and a transfer support such as a gel support or a membrane on which a biological material labeled with a fluorescent material is distributed (both on the sample stand 4). (Not shown) is set as a sample.

  An optical system is arranged below the sample table 4, and the sample set on the sample table 4 is irradiated with excitation light from below through the sample table 4 by the light irradiation optical system. The fluorescence from the sample passing through the table 4 is detected by the detection optical system. The detection optical system is connected to an external terminal such as a PC (Personal computer) 5 and controls measurement conditions from the PC 5. Further, the PC 5 creates a fluorescence image of the sample based on the detection data, and displays the created fluorescence image or the like on the built-in display screen.

  FIG. 2 shows an external view of the scanning stage 6 installed at the lower part of the sample table 4. The scanning stage 6 includes a first stage 7 serving as a reference and a second stage 8 placed on the first stage 7. A scanning module 9 is placed on the second stage 8. The detection optical system for detecting the fluorescence is stored in the scanning module 9.

  The first stage 7 constituting the scanning stage 6 is provided with two guide rails 10a and 10b extending in the first scanning direction and facing each other at a constant interval. The second stage 8 is guided by the guide rail 10a of the first stage 7 and reciprocates in the first scanning direction. The second stage 8 is guided by the guide rail 10b and reciprocates in the first scanning direction. And a second guide member 12 that moves.

  Between the first guide member 11 and the second guide member 12 constituting the second stage 8, the second stage 8 extends in the second scanning direction orthogonal to the first scanning direction and faces each other at a constant interval. Two guide rails 13a and 13b are provided. The scanning module 9 is guided by the guide rail 13a and reciprocates in the second scanning direction, and the second guide is guided by the guide rail 13b and reciprocates in the second scanning direction. Member 15.

  In the scanning method using the scanning stage 6 having the above-described configuration, first, the first guide member 11 and the second guide member 12 of the second stage 8 are guided by the guide rails 10a and 10b and moved in the first scanning direction. Thus, the positioning of the second stage 8 with respect to the first stage 7 is performed. After that, the first guide member 14 and the second guide member 15 of the scanning module 9 are guided by the guide rails 13a and 13b and moved in the second scanning direction, so that the scanning module 9 is positioned with respect to the second stage 8. Done. Thereafter, the above operation is repeated to scan the sample 16 two-dimensionally.

  That is, in the present embodiment, the moving means in the first scanning direction is constituted by the guide rails 10a and 10b and the first and second guide members 11 and 12, and the moving means in the second scanning direction. The guide rails 13a and 13b and the first and second guide members 14 and 15 are configured.

  Although not described in detail, the first and second guide members 11 and 12 of the second stage 8 are provided below the scanning stage 6 below the sample stage 4 of the main body 2 constituting the casing. In the first scanning direction, motors, drive belts, ball screws, gears, control boards, power supplies, wirings, etc. for moving the first and second guide members 14, 15 of the scanning module 9 in the second scanning direction A drive unit is installed.

  FIG. 3 is a longitudinal sectional view showing a schematic configuration of the scanning module 9 placed on the second stage 8. In FIG. 3, an objective lens serving as the lens element for condensing the fluorescence from the sample 16 set on the sample table 4 is located near the sample table (glass) 4 in the upper part of the scanning module 9. 17 is arranged. Furthermore, at a position where the optical axis of the objective lens 17 and the optical axis of the light source 18 for excitation light are orthogonal, excitation light such as laser light emitted from the light source 18 and condensed by a lens group 19 composed of a plurality of lenses. The reflection mirror 20 that reflects the light beam so as to enter the objective lens 17 is disposed.

  The objective lens 17 is housed in a lens holder 21, and the lens holder 21 can be moved in the optical axis direction of the objective lens 17 by a drive unit 22 such as a stepping motor. Thus, the objective lens 17 can move in the optical axis direction together with the lens holder 21.

  Further, below the reflection mirror 20 on the optical axis of the objective lens 17, a first lens 23 for converting fluorescence from the sample 16 collected by the objective lens 17 into parallel light in order from the reflection mirror 20 side, An excitation light cutting wavelength filter 24, a second lens 25 for condensing the fluorescence that has passed through the wavelength filter 24, and a pinhole 26 for cutting off the stray light of the fluorescence that has passed through the second lens 25 are disposed. Further, a detector 27 that detects fluorescence that has passed through the pinhole 26 is disposed below the pinhole 26 on the optical axis of the objective lens 17.

  In the scanning module 9 having the above-described configuration, the excitation light emitted from the light source 18 is focused by the lens group 19, then reflected by the reflection mirror 20, passes through the objective lens 17 and the sample stage 4, and the lower surface of the sample 16. Focused on one point. In that case, the length of the reflection mirror 20 in the longitudinal direction (direction perpendicular to the optical axis of the lens group 19) is short, the width in the direction perpendicular to the longitudinal direction is narrow, and the excitation light from the light source 18 is the objective light. Only the vicinity of the optical axis of the lens 17 (excitation light transmitting portion) passes therethrough.

  The fluorescence is isotropically emitted from the portion of the sample 16 irradiated with the excitation light to the periphery. The component of the emitted fluorescent light that has passed through the sample stage 4 made of glass and entered the objective lens 17 passes through the objective lens 17, the first lens 23, the wavelength filter 24, the second lens 25, and the pinhole 26. Passed and detected by detector 27. The detection signal from the detector 27 is sent to the PC 5 after being subjected to processing such as AD conversion by a built-in AD converter (not shown) or the like. In this way, the fluorescence intensity distribution at each measurement point on the sample 16 is recorded in the internal memory or the like.

  Here, as described above, the fluorescence that has passed through the objective lens 17 is guided toward the first lens 23 as focused light. Then, the light is refracted by the first lens 23 so as to be substantially parallel to the optical axis. The second lens 25 condenses the fluorescence. Moreover, the pinhole 26 is arrange | positioned in order to cut a stray light spatially. The excitation light cutting wavelength filter 24 is disposed, for example, in a rotating folder (not shown) or the like, and can be replaced with a filter of another wavelength according to the wavelength of the excitation light.

  Hereinafter, the objective lens 17 which is a feature of the present application will be described in detail.

  FIG. 4 is a longitudinal sectional view of the objective lens 17. As can be seen from FIG. 4, the central portion including the optical axis in the objective lens 17 includes an incident-side convex surface 28a and an output-side convex surface 28b protruding along the optical axis, and functions as a normal convex lens (only by refraction). This is a convex lens portion 28 having light deflection. Of the fluorescence emitted from the sample 16, the fluorescence a having a small emission angle passes through the convex lens portion 28 and is condensed toward the first lens 23.

  A peripheral portion of the exit-side convex surface 28b (convex lens portion 28) of the objective lens 17 is a truncated cone-shaped cylindrical body 29 that opens downward. Of the fluorescence emitted from the sample 16, the fluorescence b having a large radiation angle that does not enter the convex lens portion 28 enters the cylindrical body 29 from the incident side end face 29 a of the cylindrical body 29, and enters the incident side. The light is totally reflected by the outer peripheral surface 29b continuing to the end surface 29a, deflected to the optical axis side, and emitted toward the first lens 23 from the emission side end surface 29c continuously continuing to the outer peripheral surface 29b.

  As described above, among the fluorescent light emitted from the sample 16, fluorescent light having a large radiation angle that does not enter the convex lens portion 28 is totally reflected by the outer peripheral surface 29 b of the cylindrical body 29, so that the normal convex lens Light with a large radiation angle that cannot be collected can also be collected. Therefore, the sensitivity of the detector 27 can be increased.

  In addition, the lens element itself can be formed more compactly than the objective lens of the fluorescence detection apparatus 1 can be realized by using a normal convex lens having an NA equivalent to that of the objective lens 17.

  FIG. 5 shows an example of a specific shape of the objective lens 17. Note that the dimensions shown in FIG. 5 are merely examples, and the present invention is not limited to the dimensions shown in FIG. Here, in FIG. 5, “R” is a radius of curvature, and the unit is “mm”. In FIG. 5, the leading edge of the objective lens 17 on the optical axis on the optical axis is the origin, the X axis is taken in the direction perpendicular to the optical axis, and the Y axis is taken in the direction of the optical axis. Therefore, the origin is not the intersection of the incident-side convex surface 28a of the convex lens portion 28 and the optical axis, but the plane including the intersection line of the incident-side end surface 29a of the cylindrical body 29 and the outer peripheral surface 29b and the optical axis. It is an intersection.

  As described above, the fluorescence a having a small emission angle out of the fluorescence emitted from the sample 16 passes through the central portion (convex lens portion 28) including the optical axis in the objective lens 17 and is collected toward the first lens 23. To be lighted. As described above, the central portion of the objective lens 17 is preferably a convex lens since the light emitted radially from the point light source is condensed by refraction.

  However, in the case of the collimator lens disclosed in Patent Document 2, the exit surface of the portion that refracts a light beam having a small angle with the optical axis is a convex elliptical surface, even though the shape is the convex lens. Although it is 102c, the incident side is a concave spherical surface 102a. For this reason, the central portion including the optical axis needs to obtain a light collecting effect only on the emission side, and the light collecting efficiency as a convex lens is reduced. Therefore, design restrictions such as the need to increase the curvature of the convex elliptical surface 102c on the output side arise. Or, since the focal length of the convex ellipsoid 102c on the emission side becomes large, when this collimator lens is mounted, there arises a problem that the scanning module 9 is enlarged.

  In the present embodiment, as shown in FIG. 5, the central portion including the optical axis in the objective lens 17 is configured with a convex incident-side convex surface 28a as shown by an arrow “R1”. On the other hand, the exit surface is constituted by a convex exit-side convex surface 28b as indicated by an arrow “R2”. As described above, since both the entrance surface and the exit surface of the central portion of the lens element 17 are convex surfaces, the light collection efficiency can be easily improved. Therefore, it is not necessary to increase the curvature of the exit-side convex surface 28b on the exit side, and the focal length of the exit-side convex surface 28b on the exit side is not increased and the scanning module 9 is not enlarged.

  Further, among the fluorescence emitted from the sample 16, the fluorescence a having a small emission angle is collected by the central portion including the optical axis in the objective lens 17, while the fluorescence b having a large emission angle is collected in the periphery of the objective lens 17. When the light is condensed by the portion, the optical path of the light incident on the incident surface of the central portion and the optical path of the light incident on the incident surface of the peripheral portion may be clearly separated in the objective lens 17. desirable.

  However, in the case of the collimator lens disclosed in the above-mentioned Patent Document 2, the light at the central part that is incident on the spherical surface 102a and reaches the convex elliptical surface 102c, and the convex elliptical surface 102b that is incident on the spherical surface 102a. It is not clearly separated from the light in the surrounding area. Therefore, there is light that enters the spherical surface 102a, reaches the concave elliptical surface 102d, is totally reflected, and becomes stray light.

  In the present embodiment, as shown in FIG. 5, the shape of the incident surface of the objective lens 17 is configured by a convex incident-side convex surface 28a as shown by an arrow “R1” at the central portion including the optical axis. On the other hand, the peripheral portion (cylindrical body 29) of the central portion is constituted by a convex incident side end face 29a as indicated by an arrow "R3". In this way, the central portion and the peripheral portion on the incident surface are formed with different curved surfaces, and a concave (valley) constricted portion is formed at the boundary between the central portion and the peripheral portion. Therefore, the central portion and the peripheral portion on the incident surface are clearly separated.

  Therefore, the light incident on the incident side convex surface 28a of the central portion (convex lens portion 28) is refracted to the optical axis side of the objective lens 17, whereas the incident side of the peripheral portion (tubular body 29). The light incident on the end surface 29 a is refracted toward the outer peripheral surface 29 b located on the side opposite to the optical axis of the objective lens 17. Thus, the light incident on the incident-side convex surface 28a and the light incident on the incident-side end surface 29a are completely different from each other in the refraction direction. The light incident on the incident-side end surface 29a can be prevented from reaching the surface between the exit-side convex surface 28b of the central portion and the outer peripheral surface 29b of the peripheral portion, and the exit-side convex surface 28b and the outer peripheral surface 29b It is possible to prevent the light reaching the surface between the two from becoming stray light.

  Further, the optical path of the light incident on the incident-side convex surface 28 a of the central portion on the incident surface of the objective lens 17 and the optical path of the light incident on the incident-side end surface 29 a of the peripheral portion are in the objective lens 17. The shapes of the incident side convex surface 28a and the incident side end surface 29a are set so as not to cross each other.

  Therefore, all of the light incident on the incident side convex surface 28a of the central portion reaches the convex output side convex surface 28b which is the output surface, whereas the light incident on the incident side end surface 29a of the peripheral portion. All of this reaches the outer peripheral surface 29b which is a reflection surface. As a result, stray light is not generated by light incident on the entrance surface of the objective lens 17 and reaching the surfaces other than the exit-side convex surface 28b and the outer peripheral surface 29b.

  Further, the exit surface at the central portion of the objective lens 17 is constituted by a convex exit-side convex surface 28b as shown by an arrow “R2” in FIG. Therefore, in the central portion of the objective lens 17, the fluorescence having a small emission angle out of the fluorescence emitted from the sample 16 by the cooperation of the incident-side convex surface 28a that is the incident surface and the output-side convex surface 28b that is the output surface. a can be effectively collected toward the detector 27.

  Further, the incident surface in the peripheral portion of the objective lens 17 is constituted by the convex incident side end surface 29a as described above. As described above, the incident surface of the objective lens 17 is formed such that the convex incident side convex surface 28a of the central portion and the convex incident side end surface 29a of the peripheral portion have a concave (valley) constricted portion as a boundary. It is configured in an independent convex shape adjacent to each other. Therefore, the light condensing effect by the convex lens can be given to the incident surface also in the peripheral portion, and the irradiation area of the light incident from the incident side end surface 29a and irradiating the outer peripheral surface 29b can be reduced. . As a result, the length of the outer peripheral surface 29b of the objective lens 17 in the optical axis direction can be shortened, and the entire objective lens 17 can be reduced in size.

  Further, the reflection surface in the peripheral portion of the objective lens 17 is constituted by an outer peripheral surface 29b that is convex toward the outside of the objective lens 17 as indicated by an arrow “R4” in FIG. The fact that the outer peripheral surface (reflection surface) 29b is convex outward in this way means that the outer peripheral surface 29b can be regarded as a concave mirror when viewed from the light in the objective lens 17, and the outer peripheral surface 29b is a concave mirror. In principle, the reflected light can be collected.

  That is, the peripheral portion of the objective lens 17 collects incident light by refracting and collecting the incident light like a convex lens by the convex incident-side end surface 29a, and reflecting it like a concave mirror by the convex outer peripheral surface 29b. It has a two-stage light condensing function. Therefore, the light condensing property can be improved as compared with the case where any one of the light condensing functions is performed alone.

  Further, the incident-side end surface 29a in the peripheral portion of the objective lens 17 is formed so that light incident from the incident-side end surface 29a is incident on the outer peripheral surface 29b so as to satisfy the total reflection condition.

  Therefore, the light incident from the incident side end face 29a in the peripheral portion of the objective lens 17 is totally reflected by the outer peripheral surface 29b and can travel in the peripheral portion toward the exit surface.

  In the present embodiment, incident light from the incident side end face 29a is totally reflected by the outer peripheral surface 29b of the cylindrical body 29 in the peripheral portion. However, the present invention is not limited to total reflection, and may be simple reflection. That is, a metal reflection film may be formed on the outer peripheral surface 29b and reflected by the metal reflection film.

  Next, the first lens 23 will be described in detail.

  FIG. 6 is a longitudinal sectional view of the first lens 23. However, FIG. 6A includes a ray diagram of fluorescence when the sample 16 is placed directly on the sample table 4 (hereinafter referred to as “first case”). Further, FIG. 6B shows a case where the sample 16 is enclosed in a two-dimensional electrophoresis substrate 31 (see FIG. 8) and placed on the sample table 4 (hereinafter referred to as “second case”). Includes a fluorescence ray diagram.

  As shown in FIG. 6, the first lens 23 includes a concave lens portion 32 having a concave curved surface 32c formed on a plane 32a of two planes 32a and 32b facing each other, and two planes 33a and 33b facing each other. The convex lens part 33 in which the convex curved surface 33c is formed in the inclined part formed only around the flat surface 33b of the above, and the flat surface 33a of the convex lens part 33 and the flat surface 32b of the concave lens part 32 are laminated to face each other. have.

  Of the fluorescence emitted from the sample 16, the fluorescence a that has passed through the convex lens portion 28 in the central portion of the objective lens 17, as shown in FIG. 6, in both the first case and the second case. Both pass through the flat surface 33 b in the convex lens portion 33 and the concave curved surface 32 c in the concave lens portion 32.

  On the other hand, of the fluorescence emitted from the sample 16, the fluorescence b totally reflected by the cylindrical body 29 in the peripheral portion of the objective lens 17 is shown in FIG. 6 (a). As shown in FIG. 4, the convex lens 33 passes through a convex curved surface 33c and a concave curved surface 32c of the concave lens portion 32. In the second case, as shown in FIG. 6 (b), the light passes through a flat surface 33 b in the convex lens portion 33 and a concave curved surface 32 c in the concave lens portion 32.

  The first lens 23 may be formed by simply laminating the concave lens portion 32 and the convex lens portion 33 with each other, or may be formed by bonding the concave lens portion 32 and the convex lens portion 33. . Or you may comprise the concave lens part 32 and the convex lens part 33 integrally.

  FIG. 7 shows an example of a specific shape of the first lens 23. Note that the dimensions shown in FIG. 7 are examples, and the present invention is not limited to the dimensions shown in FIG. Here, in FIG. 7, “R” is a radius of curvature, and the unit is “mm”. The rational Bezier curve is as shown in FIG. In FIG. 7, the first lens 23 has the leading end on the incident side on the optical axis as the origin, the X axis is taken in the direction perpendicular to the optical axis, and the Y axis is taken in the direction of the optical axis. . Therefore, the origin is the intersection of the plane 33b of the convex lens portion 33 and the optical axis.

  As described above, in the present embodiment, the first lens 23 is divided into the concave lens portion 32 in which the concave curved surface 32c is formed at the center of the plane 32a, and the convex lens portion in which the convex curved surface 33c is formed around the plane 33b. 33. Then, as shown in FIG. 6, from the center to the outside, the first region passing through the region A1 of the flat surface 33b and the region B1 of the concave curved surface 32c, and the region A2 of the flat surface 33b and the region B2 of the concave curved surface 32c are passed. A second region and a third region passing through the region A3 of the convex curved surface 33c and the region B3 of the concave curved surface 32c are provided.

  Here, the first region and the second region are regions passing through the flat surface 33b of the convex lens portion 33 and the concave curved surface 32c of the concave lens portion 32, and the incident light beam is made parallel by the optical axis and diverges as a total. It is an area to be made. The third region is a region that passes through the convex curved surface 33c of the convex lens portion 33 and the concave curved surface 32c of the concave lens portion 32, and is a region that collimates the incident light beam by the optical axis and collects the light as a total. is there.

  Then, in the “second case” where the optical path after being totally reflected by the objective lens 17 is likely to be on the optical axis side (center side), the fluorescence b totally reflected by the objective lens 17 is shown in FIG. As shown in b), the light is incident on the second region of the first lens 23. In this case, the second region is a region for making incident light rays parallel to the optical axis and diverging as a total. For this purpose, as shown in FIG. 8, if the light totally reflected by the objective lens 17 is collected, the light beams of the fluorescence b emitted from the second region of the first lens 23 are substantially the same. It is parallel and substantially parallel to the optical axis.

  Further, in the “first case”, the fluorescence b totally reflected by the objective lens 17 is made incident on the third region of the first lens 23 as shown in FIG. In this case, the third region is a region that collimates incident light rays by the optical axis and collects the light rays as a total. Therefore, if light that is totally reflected by the objective lens 17 and incident on the first lens 23 is diverged, the light beams of the fluorescence b emitted from the third region of the first lens 23 are substantially parallel to each other. In addition, it is substantially parallel to the optical axis.

  Here, in order to make the light totally reflected by the objective lens 17 enter the first lens 23 so as to diverge, the light totally reflected by the objective lens 17 is made to enter the first lens 23 as shown in FIG. It may be once condensed before being incident.

  As described above, in the “second case”, the light totally reflected by the objective lens 17 can be incident on the second region of the first lens 23 while being condensed, and the “ In the “first case”, the light totally reflected by the objective lens 17 is once condensed and then diverged while being incident on the third region of the first lens 23 in FIGS. 5 and 7. As shown, the angle and shape of the reflecting surface (outer peripheral surface) 29b of the objective lens 17, the shape of the exit side end surface 29c through which the totally reflected light passes, the inclination angles of the convex curved surface 33c and the concave curved surface 32c of the first lens 23, and The shape is set.

  The “first case” in which the sample 16 is directly placed on the sample stage 4, and the “second case” in which the sample 16 is enclosed in the two-dimensional electrophoresis substrate 31 and placed on the sample stage 4. In the case of “,” the thickness of the light transmission plate is different, so the apparent light source position with respect to the point light source on the lower surface of the sample 16 is different.

  In the present embodiment, the shapes of the objective lens 17 and the first lens 23 are set as shown in FIGS. Accordingly, even if the distance from the objective lens 17 to the apparent light source is different because the position of the apparent light source is different, the fluorescence a refracted at the central portion of the objective lens 17 and the outer periphery of the peripheral portion The fluorescence b totally reflected by the surface 29b can be made substantially parallel to the optical axis when it is emitted from the first lens 23, as shown in FIGS. Therefore, the stray light can be accurately cut by the wavelength filter 24.

As described above, the lens element of the present invention is
A central portion for condensing the light emitted radially from the point light source by refraction;
A peripheral portion that is adjacent to the periphery of the central portion and collects the light from the point light source by reflection;
The central part is
The light from the point light source is incident, and the incident-side convex surface 28a having a convex curved surface shape toward the outer side in the optical axis direction,
While emitting light from the incident-side convex surface 28a, and including an output-side convex surface 28b having a curved surface shape convex toward the outside in the optical axis direction,
The above peripheral part is
An incident-side end face 29a on which light from the point light source is incident;
An outer peripheral surface 29b that is formed continuously with the incident side end surface 29a and reflects the light from the incident side end surface 29a inside;
An emission side end face 29c for emitting the light internally reflected by the outer peripheral face 29b,
A concave boundary portion is formed at the boundary between the incident-side convex surface 28a in the central portion and the incident-side end surface 29a in the peripheral portion.

  According to the above configuration, the central portion including the optical axis has the incident surface formed by the convex incident-side convex surface 28a, and the output surface is formed by the convex output-side convex surface 28b. Can be improved. Therefore, it is not necessary to increase the curvature of the exit-side convex surface 28b on the exit side, and the focal length of the exit-side convex surface 28b on the exit side is not increased and the scanning module 9 is not enlarged.

  Furthermore, a concave boundary is formed on the incident surface at the boundary between the incident-side convex surface 28a in the central portion and the incident-side end surface 29a in the peripheral portion. Therefore, the refraction directions of the light incident on the incident-side convex surface 28a and the light incident on the incident-side end surface 29a are completely different, and the central portion and the peripheral portion on the incident surface are clearly separated. Therefore, the light incident on the incident-side convex surface 28a and the light incident on the incident-side end surface 29a can be prevented from reaching the surface between the outgoing-side convex surface 28b and the outer peripheral surface 29b. It is possible to prevent the light reaching the surface between the surface 29b from becoming stray light.

In the lens element of one embodiment,
The incident-side convex surface 28a in the central portion and the incident-side end surface 29a in the peripheral portion are such that the optical path of light incident from the incident-side convex surface 28a and the optical path of light incident from the incident-side end surface 29a are the concave shape. They have shapes that are separated from each other and do not cross each other at the boundary.

  According to this embodiment, the optical path of the light incident from the incident-side convex surface 28a and the optical path of the light incident from the incident-side end surface 29a do not intersect. As a result, all of the light incident on the incident-side convex surface 28a in the central portion reaches the incident-side end surface 29a in the peripheral portion, whereas all of the light reaches the convex outgoing-side convex surface 28b that is the output surface. All of the light that reaches the outer peripheral surface 29b, which is the reflecting surface, reaches.

  Therefore, stray light is prevented from being generated by light that is incident on the incident surface and reaches the surfaces other than the exit-side convex surface 28b and the outer peripheral surface 29b.

In the lens element of one embodiment,
The incident-side end surface 29a in the peripheral portion has a curved surface shape that is convex outward.

  According to this embodiment, the incident-side end surface 29a in the peripheral portion has a curved surface shape that is convex outward. Therefore, the light condensing effect by the convex lens can be given to the incident surface also in the peripheral portion, and the irradiation area of the light incident from the incident side end surface 29a and irradiating the outer peripheral surface 29b can be reduced. As a result, the length of the outer peripheral surface 29b in the optical axis direction can be shortened, and the entire lens element 17 can be reduced in size.

In the lens element of one embodiment,
The outer peripheral surface 29b in the peripheral portion has a curved surface shape that is convex outward.

  According to this embodiment, the outer peripheral surface (reflective surface) 29b has a curved surface convex toward the outside, and can be regarded as a concave mirror when viewed from the light in the lens element 17. Therefore, the outer peripheral surface 29b can collect the reflected light by the principle of a concave mirror.

  In other words, the peripheral portion of the lens element 17 collects the incident light by refracting it like a convex lens by the convex incident side end face 29a and further reflecting it like a concave mirror by the convex outer peripheral face 29b. It has a two-stage light condensing function. Therefore, the light condensing property can be improved as compared with the case where any one of the light condensing functions is performed alone.

In the lens element of one embodiment,
The incident side end face 29a in the peripheral portion has a shape capable of guiding the light incident from the incident side end face 29a to the outer peripheral face 29b so as to satisfy the total reflection condition.

  According to this embodiment, the light incident from the incident side end surface 29a is incident on the outer peripheral surface 29b so as to satisfy the total reflection condition. Therefore, the light incident from the incident side end face 29a in the peripheral portion of the lens element 17 is totally reflected by the outer peripheral surface 29b and can travel in the peripheral portion toward the exit surface.

1 ... fluorescence detection device,
4 ... Sample stand
5 ... PC,
6 ... Scanning stage,
9 ... Scanning module,
16 ... Sample,
17 ... Objective lens,
18 ... light source,
20 ... reflecting mirror,
23. First lens,
24 ... wavelength filter,
25 ... second lens,
26 ... pinhole,
27. Detector,
28, 33 ... convex lens part,
28a: Incident side convex surface,
28b ... convex surface on the emission side,
29 ... cylindrical body,
29a: incident side end face,
29b ... outer peripheral surface,
29c ... emitting side end face,
31 ... Substrate for two-dimensional electrophoresis,
32 ... concave lens part,
32a, 32b, 33a, 33b ... plane,
32c ... concave curved surface,
33c: Convex curved surface.

  The present invention relates to a lens element used for an objective lens or the like of a fluorescence detection apparatus that reads fluorescent labels distributed two-dimensionally.

  Conventionally, a fluorescence detection system using a fluorescent dye as a labeling substance has been widely used in the fields of biochemistry and molecular biology. By using this fluorescence detection system, it is possible to evaluate gene sequences, gene mutation / polymorphism analysis, protein separation and identification, and the like, which are used for development of drugs and the like.

  As an evaluation method using a fluorescent label as described above, a method is often used in which biological compounds such as proteins are distributed in a gel by electrophoresis and the distribution of the biological compounds is obtained by fluorescence detection. ing. In the electrophoresis, an electrode is placed in a solution such as a buffer solution, and an electric field gradient is generated in the solution by flowing a direct current. At this time, when there is a charged protein, DNA (Deoxyribonucleic acid: deoxyribonucleic acid) or RNA (ribonucleic acid: ribonucleic acid) in the solution, the positively charged molecule is the cathode, the negatively charged molecule is The biomolecules can be separated by being attracted to the anode.

  Two-dimensional electrophoresis, which is one of the evaluation methods using electrophoresis, is an evaluation method that distributes biomolecules two-dimensionally in a gel by combining two types of electrophoresis methods. Proteomic analysis It is considered the most effective way to do it.

  Examples of the combination of the electrophoresis include, for example, “isoelectric focusing using the difference in isoelectric point of each protein” as the first dimension and “SDS that performs separation based on the molecular weight of the protein” as the second dimension. -PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) "is mainly used. A fluorescent dye is applied to the protein as the biomolecule thus separated before or after electrophoresis.

  Furthermore, the gel support on which the biomolecules (proteins) prepared as described above are two-dimensionally distributed is irradiated with excitation light, and the generated fluorescence intensity is obtained, and the fluorescence distribution (protein Distribution) Image readers that display images are widely used in the fields of biochemistry and molecular biology.

  As a method for maintaining the two-dimensional distribution of the biomolecules, not only the gel is retained in the gel, but also the protein is separated from the gel and then the membrane is separated from the gel using electrophoresis or capillary action. There is also a method of transferring to the surface. In that case, as in the case of image reading using the gel support, the fluorescence distribution on the transfer support, which is the membrane, can be imaged by an image reading device.

  As an image reading device that reads a biomolecule distribution image from a gel support or transfer support in which biomolecules are two-dimensionally distributed as described above, an image disclosed in Japanese Patent Laid-Open No. 10-3134 (Patent Document 1) There is a reader.

  In the conventional image reading apparatus, a mirror having a hole in the center is mounted on an optical head moved in the main scanning direction, and a transfer support on which electrophoresis of denatured DNA labeled with a fluorescent substance is recorded is recorded. On the other hand, a laser beam (excitation light) having a wavelength corresponding to the wavelength of the fluorescent material from the light source is irradiated through the hole of the mirror. Then, the fluorescence emitted when the fluorescent dye in the transfer support is excited is reflected around the hole of the mirror, and is detected by being photoelectrically converted by a multiplier. Thus, image data for one line is stored in the line buffer. Hereinafter, by repeating the above operation while moving the optical head in the sub-scanning direction orthogonal to the main scanning direction, a two-dimensional visible image (fluorescent image) is obtained by the image processing apparatus.

  As described above, in the conventional image reading apparatus, since excitation light is irradiated to the transfer support without using a dichroic mirror, strong excitation energy is higher than that of a method in which excitation light is irradiated through a dichroic mirror. The S / N of a signal (image information) that can be applied to the transfer support and photoelectrically detected can be improved.

  However, when detecting weak fluorescence, further improvement in S / N is required.

  In order to improve the S / N of the photoelectrically detected signal (image information), the fluorescent dye is excited and emitted by irradiation with excitation light such as laser light, and is emitted in an isotropic manner. It is necessary to collect as much as possible. As described above, as a lens element capable of efficiently condensing light that is isotropically spread and emitted, a collimator lens disclosed in the republished WO2008 / 0669143 (Patent Document 2) and Japanese Patent Application Laid-Open No. 2010-114044 (Patent Document) There is an optical member disclosed in Document 3).

  In the collimator lens disclosed in Patent Document 2, as shown in FIG. 10, the entrance surface is a spherical surface, and the exit surface is a composite of a convex ellipsoid on the center side and a concave ellipsoid on the peripheral side. The side surface is a convex elliptical surface. The light beam from the light source 101 is incident on the spherical surface 102 a that is the incident surface of the collimator lens 102 substantially perpendicularly. Among them, a light beam having a small angle with the optical axis is refracted by the convex elliptical surface 102c, which is an output surface, and is emitted as a parallel light beam. In addition, a light beam having a large angle with the optical axis is totally reflected by the convex elliptical surface 102b which is the side surface and is collected at the second focal point. The light beam that is totally reflected by the ellipsoidal surface 102b and collected at the second focal point is refracted by the concave ellipsoidal surface 102d that is the emission surface, and is emitted as a parallel light beam.

  Thus, the light beam emitted from the light source 101 is converted into substantially parallel light by the collimator lens 102.

  Further, in the optical member disclosed in Patent Document 3, as shown in FIG. 11, the incident surface 106 corresponding to the light emitting portion 105 and the emission side facing the incident surface 106 are integrally formed. A cylindrical lens unit 107 and a reflecting surface 108 continuous with the incident surface 106 are provided. Then, the light emitted from the linear light emitting unit 105 and radiated at a narrow angle is condensed linearly by the cylindrical lens unit 107. Further, the light radiated at a wide angle is condensed at the focal point F of the cylindrical lens unit 107 by the total reflection of the reflection surface 108.

  As described above, in any of the collimator lens and the optical member, the light condensing rate is obtained by condensing the light beam having a large angle with the optical axis from the light source or the light emitting unit by total reflection on the side surface. It is possible to increase.

  However, the conventional collimator lens and the optical member have the following problems.

  That is, for example, in the case of the collimator lens disclosed in Patent Document 2, the entire incident surface on which the light from the light source 101 enters is composed of one spherical surface 102a. The light source 101 is located at the center of the spherical surface 102a. For this reason, the light from the light source 101 enters the spherical surface 102a substantially perpendicularly, and is uniformly incident on the entire incident surface. Therefore, the light at the central part that is incident on the spherical surface 102a that is the incident surface and reaches the convex elliptical surface 102c that is the output surface, and the convex elliptical surface that is incident on the spherical surface 102a that is the incident surface and is the total reflection surface The light in the peripheral part reaching 102b is not clearly separated.

  Therefore, there is a gap between the light ray incident on the spherical surface 102a depicted in FIG. 10 and reaching the convex elliptical surface 102c and the light ray incident on the spherical surface 102a and reaching the convex elliptical surface 102b. Thus, there is light that is totally reflected by the concave elliptical surface 102d that is the exit surface. Such light totally reflected by the elliptical surface 102d is stray light because it is not in the optical path assumed to be collected. In particular, when the collimator lens is used in a fluorescence detection apparatus, there is a problem that the fluorescence detection accuracy decreases due to the presence of the stray light.

  Furthermore, since the entire incident surface is composed of one spherical surface (concave surface) 102a, a light condensing effect on the incident surface cannot be expected. Accordingly, it is necessary to increase the condensing efficiency on the exit side accordingly, and there is a problem that design restrictions such as the need to increase the curvature of the convex elliptical surface 102c on the exit side, and the elliptical surface 102c. Therefore, when the collimator lens is used in the fluorescence detection device, there arises a problem that the fluorescence detection device is enlarged.

  The above problem also occurs in the case of the optical member disclosed in Patent Document 3. That is, the entire incident surface on which the light from the light emitting unit 105 is incident is composed of the incident surface 106 that is a single plane. Therefore, the light from the light emitting unit 105 is incident substantially uniformly on the entire incident surface. Therefore, the light at the central portion that is incident on the incident surface 106 and reaches the cylindrical lens portion 107 and the light at the peripheral portion that is incident on the incident surface 106 and reaches the reflective surface 108 are not clearly separated. For this reason, light that becomes stray light exists between the light at the central portion and the light at the peripheral portion because there is no optical path that is supposed to be condensed.

  Further, since the entire incident surface is composed of the incident surface 106 which is a single plane, a light condensing effect on the incident surface cannot be expected. Therefore, it is necessary to increase the condensing efficiency on the output side by that amount, which causes a problem of design restrictions and a problem that the fluorescence detection apparatus is enlarged.

Japanese Patent Laid-Open No. 10-3134 Republished WO2008 / 069143 JP 2010-114044 A

  Accordingly, an object of the present invention is to provide a lens element capable of increasing the light collection efficiency and the detection accuracy while suppressing an increase in size.

In order to solve the above problems, the lens element of the present invention is
A central portion for condensing the light emitted radially from the point light source by refraction;
A peripheral portion that is adjacent to the periphery of the central portion and collects the light from the point light source by reflection;
The central part is
While the light from the point light source is incident, the incident side convex surface having a convex curved surface shape toward the outer side in the optical axis direction,
While emitting light from the incident side convex surface, and including an output side convex surface having a curved surface shape convex toward the outside in the optical axis direction,
The above peripheral part is
An incident side end surface on which light from the point light source is incident;
An outer peripheral surface for reflecting the light from the incident side end surface inside;
And an emission side end surface for emitting the light internally reflected by the outer peripheral surface,
At the boundary between the incident-side convex surface in the central portion and the incident-side end surface in the peripheral portion, a concave boundary is formed ,
The exit-side convex surface in the central portion and the exit-side end surface in the peripheral portion are arranged apart from each other,
The incident-side convex surface in the central portion and the incident-side end surface and the outer peripheral surface in the peripheral portion are such that the optical path of light incident from the incident-side convex surface and the optical path of light incident from the incident-side end surface are the concave shapes. The light incident from the incident-side convex surface is not separated and intersected with each other, and all the light incident from the incident-side convex surface reaches the output-side convex surface of the central portion, while the light incident from the incident-side end surface is All have a shape that reaches the exit side end face of the peripheral part,
The exit-side convex surface in the central portion and the exit-side end surface in the peripheral portion are such that the optical path of light exiting from the exit-side convex surface and the optical path of light exiting from the exit-side end surface do not intersect each other. It is characterized by having such a shape .

In the lens element of one embodiment,
The incident-side end surface in the peripheral portion has a curved surface shape that is convex outward.

In the lens element of one embodiment,
The outer peripheral surface in the peripheral portion has a curved surface shape that is convex outward.

In the lens element of one embodiment,
The incident side end face in the peripheral portion has a shape capable of guiding light incident from the incident side end face to the outer peripheral face so as to satisfy the total reflection condition.

  As is clear from the above, the lens element of the present invention is configured such that, in the central portion including the optical axis, the incident surface is configured with a convex incident-side convex surface, while the output surface is configured with a convex output-side convex surface. The efficiency of light collection can be easily improved. Therefore, it is not necessary to particularly increase the curvature of the exit-side convex surface on the exit side, and the focal length of the exit-side convex surface is increased and the module on which the lens element is mounted does not increase in size.

  Furthermore, a concave boundary is formed on the incident surface at the boundary between the incident-side convex surface in the central portion and the incident-side end surface in the peripheral portion. Therefore, the refractive directions of the light incident on the incident-side convex surface and the light incident on the incident-side end surface are completely different, and the central portion and the peripheral portion on the incident surface are clearly separated. Therefore, the light incident on the incident-side convex surface and the light incident on the incident-side end surface can be prevented from reaching the surface between the output-side convex surface and the outer peripheral surface. It is possible to prevent the light reaching the surface between the outer peripheral surfaces from becoming stray light.

  That is, according to the present invention, it is possible to increase the light collection efficiency and the detection accuracy while suppressing an increase in size.

It is an external view of the fluorescence detection apparatus using the lens element of this invention. It is an external view of the scanning stage installed in the lower part of the sample stand in FIG. It is sectional drawing of the scanning module mounted on the 2nd stage in FIG. It is sectional drawing of the objective lens in FIG. It is a figure which shows an example of the specific shape of the said objective lens. It is sectional drawing of the 1st lens in FIG. It is a figure which shows an example of the specific shape of the said 1st lens. FIG. 4 is a ray diagram from an objective lens to a pinhole when a sample is sealed in a two-dimensional electrophoresis substrate in FIG. 3. It is a light ray figure at the time of mounting a sample directly in FIG. It is sectional drawing in the conventional collimator lens. It is sectional drawing in the conventional optical member.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 is an external view of a fluorescence detection apparatus in which the lens element of the present embodiment is used. The fluorescence detection apparatus 1 is roughly configured by a main body 2 that forms a casing and a lid 3 that covers an upper surface of the main body 2. A sample table 4 made of glass is provided on the upper surface of the main body 2, and a transfer support such as a gel support or a membrane on which a biological material labeled with a fluorescent material is distributed (both on the sample stand 4). (Not shown) is set as a sample.

  An optical system is arranged below the sample table 4, and the sample set on the sample table 4 is irradiated with excitation light from below through the sample table 4 by the light irradiation optical system. The fluorescence from the sample passing through the table 4 is detected by the detection optical system. The detection optical system is connected to an external terminal such as a PC (Personal computer) 5 and controls measurement conditions from the PC 5. Further, the PC 5 creates a fluorescence image of the sample based on the detection data, and displays the created fluorescence image or the like on the built-in display screen.

  FIG. 2 shows an external view of the scanning stage 6 installed at the lower part of the sample table 4. The scanning stage 6 includes a first stage 7 serving as a reference and a second stage 8 placed on the first stage 7. A scanning module 9 is placed on the second stage 8. The detection optical system for detecting the fluorescence is stored in the scanning module 9.

  The first stage 7 constituting the scanning stage 6 is provided with two guide rails 10a and 10b extending in the first scanning direction and facing each other at a constant interval. The second stage 8 is guided by the guide rail 10a of the first stage 7 and reciprocates in the first scanning direction. The second stage 8 is guided by the guide rail 10b and reciprocates in the first scanning direction. And a second guide member 12 that moves.

  Between the first guide member 11 and the second guide member 12 constituting the second stage 8, the second stage 8 extends in the second scanning direction orthogonal to the first scanning direction and faces each other at a constant interval. Two guide rails 13a and 13b are provided. The scanning module 9 is guided by the guide rail 13a and reciprocates in the second scanning direction, and the second guide is guided by the guide rail 13b and reciprocates in the second scanning direction. Member 15.

  In the scanning method using the scanning stage 6 having the above-described configuration, first, the first guide member 11 and the second guide member 12 of the second stage 8 are guided by the guide rails 10a and 10b and moved in the first scanning direction. Thus, the positioning of the second stage 8 with respect to the first stage 7 is performed. After that, the first guide member 14 and the second guide member 15 of the scanning module 9 are guided by the guide rails 13a and 13b and moved in the second scanning direction, so that the scanning module 9 is positioned with respect to the second stage 8. Done. Thereafter, the above operation is repeated to scan the sample 16 two-dimensionally.

  That is, in the present embodiment, the moving means in the first scanning direction is constituted by the guide rails 10a and 10b and the first and second guide members 11 and 12, and the moving means in the second scanning direction. The guide rails 13a and 13b and the first and second guide members 14 and 15 are configured.

  Although not described in detail, the first and second guide members 11 and 12 of the second stage 8 are provided below the scanning stage 6 below the sample stage 4 of the main body 2 constituting the casing. In the first scanning direction, motors, drive belts, ball screws, gears, control boards, power supplies, wirings, etc. for moving the first and second guide members 14, 15 of the scanning module 9 in the second scanning direction A drive unit is installed.

  FIG. 3 is a longitudinal sectional view showing a schematic configuration of the scanning module 9 placed on the second stage 8. In FIG. 3, an objective lens serving as the lens element for condensing the fluorescence from the sample 16 set on the sample table 4 is located near the sample table (glass) 4 in the upper part of the scanning module 9. 17 is arranged. Furthermore, at a position where the optical axis of the objective lens 17 and the optical axis of the light source 18 for excitation light are orthogonal, excitation light such as laser light emitted from the light source 18 and condensed by a lens group 19 composed of a plurality of lenses. The reflection mirror 20 that reflects the light beam so as to enter the objective lens 17 is disposed.

  The objective lens 17 is housed in a lens holder 21, and the lens holder 21 can be moved in the optical axis direction of the objective lens 17 by a drive unit 22 such as a stepping motor. Thus, the objective lens 17 can move in the optical axis direction together with the lens holder 21.

  Further, below the reflection mirror 20 on the optical axis of the objective lens 17, a first lens 23 for converting fluorescence from the sample 16 collected by the objective lens 17 into parallel light in order from the reflection mirror 20 side, An excitation light cutting wavelength filter 24, a second lens 25 for condensing the fluorescence that has passed through the wavelength filter 24, and a pinhole 26 for cutting off the stray light of the fluorescence that has passed through the second lens 25 are disposed. Further, a detector 27 that detects fluorescence that has passed through the pinhole 26 is disposed below the pinhole 26 on the optical axis of the objective lens 17.

  In the scanning module 9 having the above-described configuration, the excitation light emitted from the light source 18 is focused by the lens group 19, then reflected by the reflection mirror 20, passes through the objective lens 17 and the sample stage 4, and the lower surface of the sample 16. Focused on one point. In that case, the length of the reflection mirror 20 in the longitudinal direction (direction perpendicular to the optical axis of the lens group 19) is short, the width in the direction perpendicular to the longitudinal direction is narrow, and the excitation light from the light source 18 is the objective light. Only the vicinity of the optical axis of the lens 17 (excitation light transmitting portion) passes therethrough.

  The fluorescence is isotropically emitted from the portion of the sample 16 irradiated with the excitation light to the periphery. The component of the emitted fluorescent light that has passed through the sample stage 4 made of glass and entered the objective lens 17 passes through the objective lens 17, the first lens 23, the wavelength filter 24, the second lens 25, and the pinhole 26. Passed and detected by detector 27. The detection signal from the detector 27 is sent to the PC 5 after being subjected to processing such as AD conversion by a built-in AD converter (not shown) or the like. In this way, the fluorescence intensity distribution at each measurement point on the sample 16 is recorded in the internal memory or the like.

  Here, as described above, the fluorescence that has passed through the objective lens 17 is guided toward the first lens 23 as focused light. Then, the light is refracted by the first lens 23 so as to be substantially parallel to the optical axis. The second lens 25 condenses the fluorescence. Moreover, the pinhole 26 is arrange | positioned in order to cut a stray light spatially. The excitation light cutting wavelength filter 24 is disposed, for example, in a rotating folder (not shown) or the like, and can be replaced with a filter of another wavelength according to the wavelength of the excitation light.

  Hereinafter, the objective lens 17 which is a feature of the present application will be described in detail.

  FIG. 4 is a longitudinal sectional view of the objective lens 17. As can be seen from FIG. 4, the central portion including the optical axis in the objective lens 17 includes an incident-side convex surface 28a and an output-side convex surface 28b protruding along the optical axis, and functions as a normal convex lens (only by refraction). This is a convex lens portion 28 having light deflection. Of the fluorescence emitted from the sample 16, the fluorescence a having a small emission angle passes through the convex lens portion 28 and is condensed toward the first lens 23.

  A peripheral portion of the exit-side convex surface 28b (convex lens portion 28) of the objective lens 17 is a truncated cone-shaped cylindrical body 29 that opens downward. Of the fluorescence emitted from the sample 16, the fluorescence b having a large radiation angle that does not enter the convex lens portion 28 enters the cylindrical body 29 from the incident side end face 29 a of the cylindrical body 29, and enters the incident side. The light is totally reflected by the outer peripheral surface 29b continuing to the end surface 29a, deflected to the optical axis side, and emitted toward the first lens 23 from the emission side end surface 29c continuously continuing to the outer peripheral surface 29b.

  As described above, among the fluorescent light emitted from the sample 16, fluorescent light having a large radiation angle that does not enter the convex lens portion 28 is totally reflected by the outer peripheral surface 29 b of the cylindrical body 29, so that the normal convex lens Light with a large radiation angle that cannot be collected can also be collected. Therefore, the sensitivity of the detector 27 can be increased.

  In addition, the lens element itself can be formed more compactly than the objective lens of the fluorescence detection apparatus 1 can be realized by using a normal convex lens having an NA equivalent to that of the objective lens 17.

  FIG. 5 shows an example of a specific shape of the objective lens 17. Note that the dimensions shown in FIG. 5 are merely examples, and the present invention is not limited to the dimensions shown in FIG. Here, in FIG. 5, “R” is a radius of curvature, and the unit is “mm”. In FIG. 5, the leading edge of the objective lens 17 on the optical axis on the optical axis is the origin, the X axis is taken in the direction perpendicular to the optical axis, and the Y axis is taken in the direction of the optical axis. Therefore, the origin is not the intersection of the incident-side convex surface 28a of the convex lens portion 28 and the optical axis, but the plane including the intersection line of the incident-side end surface 29a of the cylindrical body 29 and the outer peripheral surface 29b and the optical axis. It is an intersection.

  As described above, the fluorescence a having a small emission angle out of the fluorescence emitted from the sample 16 passes through the central portion (convex lens portion 28) including the optical axis in the objective lens 17 and is collected toward the first lens 23. To be lighted. As described above, the central portion of the objective lens 17 is preferably a convex lens since the light emitted radially from the point light source is condensed by refraction.

  However, in the case of the collimator lens disclosed in Patent Document 2, the exit surface of the portion that refracts a light beam having a small angle with the optical axis is a convex elliptical surface, even though the shape is the convex lens. Although it is 102c, the incident side is a concave spherical surface 102a. For this reason, the central portion including the optical axis needs to obtain a light collecting effect only on the emission side, and the light collecting efficiency as a convex lens is reduced. Therefore, design restrictions such as the need to increase the curvature of the convex elliptical surface 102c on the output side arise. Or, since the focal length of the convex ellipsoid 102c on the emission side becomes large, when this collimator lens is mounted, there arises a problem that the scanning module 9 is enlarged.

  In the present embodiment, as shown in FIG. 5, the central portion including the optical axis in the objective lens 17 is configured with a convex incident-side convex surface 28a as shown by an arrow “R1”. On the other hand, the exit surface is constituted by a convex exit-side convex surface 28b as indicated by an arrow “R2”. As described above, since both the entrance surface and the exit surface of the central portion of the lens element 17 are convex surfaces, the light collection efficiency can be easily improved. Therefore, it is not necessary to increase the curvature of the exit-side convex surface 28b on the exit side, and the focal length of the exit-side convex surface 28b on the exit side is not increased and the scanning module 9 is not enlarged.

  Further, among the fluorescence emitted from the sample 16, the fluorescence a having a small emission angle is collected by the central portion including the optical axis in the objective lens 17, while the fluorescence b having a large emission angle is collected in the periphery of the objective lens 17. When the light is condensed by the portion, the optical path of the light incident on the incident surface of the central portion and the optical path of the light incident on the incident surface of the peripheral portion may be clearly separated in the objective lens 17. desirable.

  However, in the case of the collimator lens disclosed in the above-mentioned Patent Document 2, the light at the central part that is incident on the spherical surface 102a and reaches the convex elliptical surface 102c, and the convex elliptical surface 102b that is incident on the spherical surface 102a. It is not clearly separated from the light in the surrounding area. Therefore, there is light that enters the spherical surface 102a, reaches the concave elliptical surface 102d, is totally reflected, and becomes stray light.

  In the present embodiment, as shown in FIG. 5, the shape of the incident surface of the objective lens 17 is configured by a convex incident-side convex surface 28a as shown by an arrow “R1” at the central portion including the optical axis. On the other hand, the peripheral portion (cylindrical body 29) of the central portion is constituted by a convex incident side end face 29a as indicated by an arrow "R3". In this way, the central portion and the peripheral portion on the incident surface are formed with different curved surfaces, and a concave (valley) constricted portion is formed at the boundary between the central portion and the peripheral portion. Therefore, the central portion and the peripheral portion on the incident surface are clearly separated.

  Therefore, the light incident on the incident side convex surface 28a of the central portion (convex lens portion 28) is refracted to the optical axis side of the objective lens 17, whereas the incident side of the peripheral portion (tubular body 29). The light incident on the end surface 29 a is refracted toward the outer peripheral surface 29 b located on the side opposite to the optical axis of the objective lens 17. Thus, the light incident on the incident-side convex surface 28a and the light incident on the incident-side end surface 29a are completely different from each other in the refraction direction. The light incident on the incident-side end surface 29a can be prevented from reaching the surface between the exit-side convex surface 28b of the central portion and the outer peripheral surface 29b of the peripheral portion, and the exit-side convex surface 28b and the outer peripheral surface 29b It is possible to prevent the light reaching the surface between the two from becoming stray light.

  Further, the optical path of the light incident on the incident-side convex surface 28 a of the central portion on the incident surface of the objective lens 17 and the optical path of the light incident on the incident-side end surface 29 a of the peripheral portion are in the objective lens 17. The shapes of the incident side convex surface 28a and the incident side end surface 29a are set so as not to cross each other.

  Therefore, all of the light incident on the incident side convex surface 28a of the central portion reaches the convex output side convex surface 28b which is the output surface, whereas the light incident on the incident side end surface 29a of the peripheral portion. All of this reaches the outer peripheral surface 29b which is a reflection surface. As a result, stray light is not generated by light incident on the entrance surface of the objective lens 17 and reaching the surfaces other than the exit-side convex surface 28b and the outer peripheral surface 29b.

  Further, the exit surface at the central portion of the objective lens 17 is constituted by a convex exit-side convex surface 28b as shown by an arrow “R2” in FIG. Therefore, in the central portion of the objective lens 17, the fluorescence having a small emission angle out of the fluorescence emitted from the sample 16 by the cooperation of the incident-side convex surface 28a that is the incident surface and the output-side convex surface 28b that is the output surface. a can be effectively collected toward the detector 27.

  Further, the incident surface in the peripheral portion of the objective lens 17 is constituted by the convex incident side end surface 29a as described above. As described above, the incident surface of the objective lens 17 is formed such that the convex incident side convex surface 28a of the central portion and the convex incident side end surface 29a of the peripheral portion have a concave (valley) constricted portion as a boundary. It is configured in an independent convex shape adjacent to each other. Therefore, the light condensing effect by the convex lens can be given to the incident surface also in the peripheral portion, and the irradiation area of the light incident from the incident side end surface 29a and irradiating the outer peripheral surface 29b can be reduced. . As a result, the length of the outer peripheral surface 29b of the objective lens 17 in the optical axis direction can be shortened, and the entire objective lens 17 can be reduced in size.

  Further, the reflection surface in the peripheral portion of the objective lens 17 is constituted by an outer peripheral surface 29b that is convex toward the outside of the objective lens 17 as indicated by an arrow “R4” in FIG. The fact that the outer peripheral surface (reflection surface) 29b is convex outward in this way means that the outer peripheral surface 29b can be regarded as a concave mirror when viewed from the light in the objective lens 17, and the outer peripheral surface 29b is a concave mirror. In principle, the reflected light can be collected.

  That is, the peripheral portion of the objective lens 17 collects incident light by refracting and collecting the incident light like a convex lens by the convex incident-side end surface 29a, and reflecting it like a concave mirror by the convex outer peripheral surface 29b. It has a two-stage light condensing function. Therefore, the light condensing property can be improved as compared with the case where any one of the light condensing functions is performed alone.

  Further, the incident-side end surface 29a in the peripheral portion of the objective lens 17 is formed so that light incident from the incident-side end surface 29a is incident on the outer peripheral surface 29b so as to satisfy the total reflection condition.

  Therefore, the light incident from the incident side end face 29a in the peripheral portion of the objective lens 17 is totally reflected by the outer peripheral surface 29b and can travel in the peripheral portion toward the exit surface.

  In the present embodiment, incident light from the incident side end face 29a is totally reflected by the outer peripheral surface 29b of the cylindrical body 29 in the peripheral portion. However, the present invention is not limited to total reflection, and may be simple reflection. That is, a metal reflection film may be formed on the outer peripheral surface 29b and reflected by the metal reflection film.

  Next, the first lens 23 will be described in detail.

  FIG. 6 is a longitudinal sectional view of the first lens 23. However, FIG. 6A includes a ray diagram of fluorescence when the sample 16 is placed directly on the sample table 4 (hereinafter referred to as “first case”). Further, FIG. 6B shows a case where the sample 16 is enclosed in a two-dimensional electrophoresis substrate 31 (see FIG. 8) and placed on the sample table 4 (hereinafter referred to as “second case”). Includes a fluorescence ray diagram.

  As shown in FIG. 6, the first lens 23 includes a concave lens portion 32 having a concave curved surface 32c formed on a plane 32a of two planes 32a and 32b facing each other, and two planes 33a and 33b facing each other. The convex lens part 33 in which the convex curved surface 33c is formed in the inclined part formed only around the flat surface 33b of the above, and the flat surface 33a of the convex lens part 33 and the flat surface 32b of the concave lens part 32 are laminated to face each other. have.

  Of the fluorescence emitted from the sample 16, the fluorescence a that has passed through the convex lens portion 28 in the central portion of the objective lens 17, as shown in FIG. 6, in both the first case and the second case. Both pass through the flat surface 33 b in the convex lens portion 33 and the concave curved surface 32 c in the concave lens portion 32.

  On the other hand, of the fluorescence emitted from the sample 16, the fluorescence b totally reflected by the cylindrical body 29 in the peripheral portion of the objective lens 17 is shown in FIG. 6 (a). As shown in FIG. 4, the convex lens 33 passes through a convex curved surface 33c and a concave curved surface 32c of the concave lens portion 32. In the second case, as shown in FIG. 6 (b), the light passes through a flat surface 33 b in the convex lens portion 33 and a concave curved surface 32 c in the concave lens portion 32.

  The first lens 23 may be formed by simply laminating the concave lens portion 32 and the convex lens portion 33 with each other, or may be formed by bonding the concave lens portion 32 and the convex lens portion 33. . Or you may comprise the concave lens part 32 and the convex lens part 33 integrally.

  FIG. 7 shows an example of a specific shape of the first lens 23. Note that the dimensions shown in FIG. 7 are examples, and the present invention is not limited to the dimensions shown in FIG. Here, in FIG. 7, “R” is a radius of curvature, and the unit is “mm”. The rational Bezier curve is as shown in FIG. In FIG. 7, the first lens 23 has the leading end on the incident side on the optical axis as the origin, the X axis is taken in the direction perpendicular to the optical axis, and the Y axis is taken in the direction of the optical axis. . Therefore, the origin is the intersection of the plane 33b of the convex lens portion 33 and the optical axis.

  As described above, in the present embodiment, the first lens 23 is divided into the concave lens portion 32 in which the concave curved surface 32c is formed at the center of the plane 32a, and the convex lens portion in which the convex curved surface 33c is formed around the plane 33b. 33. Then, as shown in FIG. 6, from the center to the outside, the first region passing through the region A1 of the flat surface 33b and the region B1 of the concave curved surface 32c, and the region A2 of the flat surface 33b and the region B2 of the concave curved surface 32c are passed. A second region and a third region passing through the region A3 of the convex curved surface 33c and the region B3 of the concave curved surface 32c are provided.

  Here, the first region and the second region are regions passing through the flat surface 33b of the convex lens portion 33 and the concave curved surface 32c of the concave lens portion 32, and the incident light beam is made parallel by the optical axis and diverges as a total. It is an area to be made. The third region is a region that passes through the convex curved surface 33c of the convex lens portion 33 and the concave curved surface 32c of the concave lens portion 32, and is a region that collimates the incident light beam by the optical axis and collects the light as a total. is there.

  Then, in the “second case” where the optical path after being totally reflected by the objective lens 17 is likely to be on the optical axis side (center side), the fluorescence b totally reflected by the objective lens 17 is shown in FIG. As shown in b), the light is incident on the second region of the first lens 23. In this case, the second region is a region for making incident light rays parallel to the optical axis and diverging as a total. For this purpose, as shown in FIG. 8, if the light totally reflected by the objective lens 17 is collected, the light beams of the fluorescence b emitted from the second region of the first lens 23 are substantially the same. It is parallel and substantially parallel to the optical axis.

  Further, in the “first case”, the fluorescence b totally reflected by the objective lens 17 is made incident on the third region of the first lens 23 as shown in FIG. In this case, the third region is a region that collimates incident light rays by the optical axis and collects the light rays as a total. Therefore, if light that is totally reflected by the objective lens 17 and incident on the first lens 23 is diverged, the light beams of the fluorescence b emitted from the third region of the first lens 23 are substantially parallel to each other. In addition, it is substantially parallel to the optical axis.

  Here, in order to make the light totally reflected by the objective lens 17 enter the first lens 23 so as to diverge, the light totally reflected by the objective lens 17 is made to enter the first lens 23 as shown in FIG. It may be once condensed before being incident.

  As described above, in the “second case”, the light totally reflected by the objective lens 17 can be incident on the second region of the first lens 23 while being condensed, and the “ In the “first case”, the light totally reflected by the objective lens 17 is once condensed and then diverged while being incident on the third region of the first lens 23 in FIGS. 5 and 7. As shown, the angle and shape of the reflecting surface (outer peripheral surface) 29b of the objective lens 17, the shape of the exit side end surface 29c through which the totally reflected light passes, the inclination angles of the convex curved surface 33c and the concave curved surface 32c of the first lens 23, and The shape is set.

  The “first case” in which the sample 16 is directly placed on the sample stage 4, and the “second case” in which the sample 16 is enclosed in the two-dimensional electrophoresis substrate 31 and placed on the sample stage 4. In the case of “,” the thickness of the light transmission plate is different, so the apparent light source position with respect to the point light source on the lower surface of the sample 16 is different.

  In the present embodiment, the shapes of the objective lens 17 and the first lens 23 are set as shown in FIGS. Accordingly, even if the distance from the objective lens 17 to the apparent light source is different because the position of the apparent light source is different, the fluorescence a refracted at the central portion of the objective lens 17 and the outer periphery of the peripheral portion The fluorescence b totally reflected by the surface 29b can be made substantially parallel to the optical axis when it is emitted from the first lens 23, as shown in FIGS. Therefore, the stray light can be accurately cut by the wavelength filter 24.

As described above, the lens element of the present invention is
A central portion for condensing the light emitted radially from the point light source by refraction;
A peripheral portion that is adjacent to the periphery of the central portion and collects the light from the point light source by reflection;
The central part is
The light from the point light source is incident, and the incident-side convex surface 28a having a convex curved surface shape toward the outer side in the optical axis direction,
While emitting light from the incident-side convex surface 28a, and including an output-side convex surface 28b having a curved surface shape convex toward the outside in the optical axis direction,
The above peripheral part is
An incident-side end face 29a on which light from the point light source is incident;
An outer peripheral surface 29b that is formed continuously with the incident side end surface 29a and reflects the light from the incident side end surface 29a inside;
An emission side end face 29c for emitting the light internally reflected by the outer peripheral face 29b,
A concave boundary portion is formed at the boundary between the incident-side convex surface 28a in the central portion and the incident-side end surface 29a in the peripheral portion.

  According to the above configuration, the central portion including the optical axis has the incident surface formed by the convex incident-side convex surface 28a, and the output surface is formed by the convex output-side convex surface 28b. Can be improved. Therefore, it is not necessary to increase the curvature of the exit-side convex surface 28b on the exit side, and the focal length of the exit-side convex surface 28b on the exit side is not increased and the scanning module 9 is not enlarged.

  Furthermore, a concave boundary is formed on the incident surface at the boundary between the incident-side convex surface 28a in the central portion and the incident-side end surface 29a in the peripheral portion. Therefore, the refraction directions of the light incident on the incident-side convex surface 28a and the light incident on the incident-side end surface 29a are completely different, and the central portion and the peripheral portion on the incident surface are clearly separated. Therefore, the light incident on the incident-side convex surface 28a and the light incident on the incident-side end surface 29a can be prevented from reaching the surface between the outgoing-side convex surface 28b and the outer peripheral surface 29b. It is possible to prevent the light reaching the surface between the surface 29b from becoming stray light.

In the lens element of one embodiment,
The incident-side convex surface 28a in the central portion and the incident-side end surface 29a in the peripheral portion are such that the optical path of light incident from the incident-side convex surface 28a and the optical path of light incident from the incident-side end surface 29a are the concave shape. They have shapes that are separated from each other and do not cross each other at the boundary.

  According to this embodiment, the optical path of the light incident from the incident-side convex surface 28a and the optical path of the light incident from the incident-side end surface 29a do not intersect. As a result, all of the light incident on the incident-side convex surface 28a in the central portion reaches the incident-side end surface 29a in the peripheral portion, whereas all of the light reaches the convex outgoing-side convex surface 28b that is the output surface. All of the light that reaches the outer peripheral surface 29b, which is the reflecting surface, reaches.

  Therefore, stray light is prevented from being generated by light that is incident on the incident surface and reaches the surfaces other than the exit-side convex surface 28b and the outer peripheral surface 29b.

In the lens element of one embodiment,
The incident-side end surface 29a in the peripheral portion has a curved surface shape that is convex outward.

  According to this embodiment, the incident-side end surface 29a in the peripheral portion has a curved surface shape that is convex outward. Therefore, the light condensing effect by the convex lens can be given to the incident surface also in the peripheral portion, and the irradiation area of the light incident from the incident side end surface 29a and irradiating the outer peripheral surface 29b can be reduced. As a result, the length of the outer peripheral surface 29b in the optical axis direction can be shortened, and the entire lens element 17 can be reduced in size.

In the lens element of one embodiment,
The outer peripheral surface 29b in the peripheral portion has a curved surface shape that is convex outward.

  According to this embodiment, the outer peripheral surface (reflective surface) 29b has a curved surface convex toward the outside, and can be regarded as a concave mirror when viewed from the light in the lens element 17. Therefore, the outer peripheral surface 29b can collect the reflected light by the principle of a concave mirror.

  In other words, the peripheral portion of the lens element 17 collects the incident light by refracting it like a convex lens by the convex incident side end face 29a and further reflecting it like a concave mirror by the convex outer peripheral face 29b. It has a two-stage light condensing function. Therefore, the light condensing property can be improved as compared with the case where any one of the light condensing functions is performed alone.

In the lens element of one embodiment,
The incident side end face 29a in the peripheral portion has a shape capable of guiding the light incident from the incident side end face 29a to the outer peripheral face 29b so as to satisfy the total reflection condition.

  According to this embodiment, the light incident from the incident side end surface 29a is incident on the outer peripheral surface 29b so as to satisfy the total reflection condition. Therefore, the light incident from the incident side end face 29a in the peripheral portion of the lens element 17 is totally reflected by the outer peripheral surface 29b and can travel in the peripheral portion toward the exit surface.

1 ... fluorescence detection device,
4 ... Sample stand
5 ... PC,
6 ... Scanning stage,
9 ... Scanning module,
16 ... Sample,
17 ... Objective lens,
18 ... light source,
20 ... reflecting mirror,
23. First lens,
24 ... wavelength filter,
25 ... second lens,
26 ... pinhole,
27. Detector,
28, 33 ... convex lens part,
28a: Incident side convex surface,
28b ... convex surface on the emission side,
29 ... cylindrical body,
29a: incident side end face,
29b ... outer peripheral surface,
29c ... emitting side end face,
31 ... Substrate for two-dimensional electrophoresis,
32 ... concave lens part,
32a, 32b, 33a, 33b ... plane,
32c ... concave curved surface,
33c: Convex curved surface.

Claims (5)

A central portion for condensing the light emitted radially from the point light source by refraction;
A peripheral portion that is adjacent to the periphery of the central portion and collects the light from the point light source by reflection;
The central part is
While the light from the point light source is incident, the incident side convex surface having a convex curved surface shape toward the outer side in the optical axis direction,
While emitting light from the incident side convex surface, and including an output side convex surface having a curved surface shape convex toward the outside in the optical axis direction,
The above peripheral part is
An incident side end surface on which light from the point light source is incident;
An outer peripheral surface for reflecting the light from the incident side end surface inside;
And an emission side end surface for emitting the light internally reflected by the outer peripheral surface,
A lens element, wherein a concave boundary portion is formed at a boundary between the incident-side convex surface at the central portion and the incident-side end surface at the peripheral portion. The lens element according to claim 1, wherein
The incident-side convex surface in the central portion and the incident-side end surface in the peripheral portion are configured such that the optical path of light incident from the incident-side convex surface and the optical path of light incident from the incident-side end surface border the concave boundary portion. The lens element has a shape that is separated from each other and does not cross each other. The lens element according to claim 1 or 2,
The lens element according to claim 1, wherein the incident-side end surface of the peripheral portion has a curved surface that is convex outward. In the lens element according to any one of claims 1 to 3,
The lens element according to claim 1, wherein the outer peripheral surface in the peripheral portion has a curved surface shape convex toward the outside. In the lens element according to any one of claims 1 to 4,
The incident-side end surface in the peripheral portion has a shape capable of guiding light incident from the incident-side end surface to the outer peripheral surface so as to satisfy a total reflection condition. element.

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