JP2023006187A - Illumination device, microscope and illumination method - Google Patents

Abstract

To suppress unevenness of light emitted from an optical propagation member.SOLUTION: Light L (outgoing light Lo) after being diffused by a diffusion plate 4 (light diffusing part) propagates through a rod integrator 5 (light propagating member). Therefore, after the light L is spread by the diffusion plate 4, the light L can be propagated by the rod integrator 5. For that reason, non-uniformity of the light L emitted from an exit surface 52 of the rod integrator 5 can be suppressed.SELECTED DRAWING: Figure 3

Description

The present invention relates to illumination technology that can be used to illuminate an object with a microscope, an exposure device, or the like.

As disclosed in Patent Literatures 1 and 2, a light propagation member such as an integrator can be used in the lighting technology for irradiating an object with light from a light emitting element. This light propagating member has an incident surface and an exit surface, and light incident from the incident surface is emitted from the exit surface after propagating inside the light propagating member. The object is irradiated with the light emitted from the exit surface in this way.

Japanese Patent Application Laid-Open No. 2002-202442 Japanese Patent Application Laid-Open No. 2016-212138

By the way, when arranging a plurality of light emitting elements to avoid interference with each other or when arranging the light emitting elements by avoiding interference with other members, the light emitting elements are opposed to the incident surface of the light propagation member. If it cannot be arranged, the angle of light incident on the incident surface will be inclined with respect to the incident surface. As a result, as will be exemplified later, the distribution of the light emitted from the exit surface becomes non-uniform, and there is a problem that the object cannot be irradiated with uniform light.

The present invention has been made in view of the above problems, and an object of the present invention is to suppress non-uniformity of light emitted from a light propagating member.

A lighting device according to the present invention includes a light-emitting element that emits light, a light-collecting optical system that collects and emits the light emitted from the light-emitting element, and a light diffusion that diffuses the light emitted from the light-collecting optical system. and a light propagation member that propagates the light diffused by the light diffusion part.

An illumination method according to the present invention comprises a step of emitting light emitted from a light emitting element while condensing it with a condensing optical system, a step of diffusing the light emitted from the condensing optical system with a light diffusion part, and a step of propagating the light diffused by the diffusing part with a light propagating member.

In the present invention (illumination device and illumination method) configured as described above, the light diffused by the light diffusion portion propagates inside the light propagation member. Therefore, the light can be propagated by the light propagation member after the light is spread by the light diffusing portion. Therefore, non-uniformity of the light emitted from the exit surface of the light propagation member can be suppressed.

Further, the light propagation member has an incident surface and an exit surface, and emits light incident from the incident surface from the exit surface, and the light diffusion unit diffuses the light between the condensing optical system and the incident surface, The illumination device may be configured such that the light emitted by the condensing optical system is diffused by the light diffusing section and then incident on the incident surface. In such a configuration, the light after being diffused by the light diffusing section enters the incident surface of the light propagating member. Therefore, after widening the divergence angle of light by the light diffusing part, the light can be made incident on the incident surface of the light propagation member and propagated by the light propagation member. Therefore, non-uniformity of the light emitted from the exit surface of the light propagation member can be suppressed.

The illumination device is configured such that the plane of incidence is flat, and the principal ray of light emitted from the light emitting element and then emitted by the condensing optical system is inclined with respect to a normal line perpendicular to the plane of incidence. may In such a lighting device in which the principal ray of light incident on the incident surface is tilted with respect to the incident surface, the light emitted from the exit surface tends to be non-uniform. On the other hand, since the diffusion member is provided to diffuse the light before it enters the incident surface, the principal ray of light is emitted from the exit surface of the light propagation member by alleviating the influence of the inclination of the principal ray with respect to the incident surface. It is possible to suppress non-uniformity of light caused by

Further, the angle θ between the principal ray of light emitted from the condensing optical system and the normal line, the divergence angle θ _NA of the light diffused by the light diffusion unit, the refractive index n of the light propagation member, and the incident The critical angle θ _C of light propagating inside the light propagation member from the surface toward the exit surface is defined by the following formula: sin(θ _NA +θ)≦n×sin(90°−θ _C )
θ _NA −θ≧0
The lighting device may be configured so as to satisfy With such a configuration, it is possible to secure light incident on the incident surface over an angular range including an angle parallel to the normal to the incident surface of the light propagation member (that is, zero degrees with respect to the normal). As a result, it is possible to effectively suppress non-uniformity of the light emitted from the exit surface of the light propagation member.

Further, the light emitted from the light emitting element has a first width in the minor axis direction, a second width longer than the first width in the major axis direction different from the minor axis direction, and the minor axis direction is , the illumination device may be configured to be included in a plane containing the principal ray and the normal of the light incident on the incident surface. With such a configuration, light can be emitted isotropically from the exit surface of the light propagation member.

Moreover, the illumination device may be configured to further include a projection optical system that projects the light emitted from the exit surface onto the placement surface on which the object is placed. With such a configuration, it is possible to project light with suppressed non-uniformity onto the arrangement surface.

Various specific examples of the light propagation member are conceivable. For example, the light propagating member may be a rod integrator or an optical fiber.

Moreover, various specific examples of the light-emitting element are assumed. For example, the light emitting device may be a laser diode.

Further, each of the plurality of light-emitting elements may be arranged as a light-emitting element, and the lighting device may be configured such that the light emitted from each of the plurality of light-emitting elements is emitted from the condensing optical system at different angles. good. In such a configuration in which a plurality of light emitting elements are arranged, the light emitted from each light emitting element is incident on the light propagating member at an angle, which tends to make the light emitted from the light propagating member non-uniform. On the other hand, since the diffusion member that diffuses the light is provided, the influence of the inclination of the light can be mitigated, and the non-uniformity of the light emitted from the light propagation member can be suppressed.

Further, a control unit for controlling emission of light from the plurality of light emitting elements is further provided, the plurality of light emitting elements emit light of different wavelengths, and the control unit controls one selected from the plurality of light emitting elements. The lighting device may be configured to cause the light emitting element to emit light. With such a configuration, the object can be irradiated with light having an appropriate wavelength according to the characteristics of the object.

Various specific examples of the light diffusing portion are assumed. For example, the light diffusing part may be a diffusion plate provided between the condensing optical system and the light propagating member and spaced apart from the light propagating member. Alternatively, the light diffusing portion may be provided on the end face of the light propagating member.

A microscope according to the present invention includes the illumination device described above, a sensor that detects light, and an observation optical system that irradiates the sensor with light emitted from an object in response to the illumination of the light from the illumination device. Therefore, non-uniformity of light emitted from the light propagation member can be suppressed.

As described above, according to the present invention, it is possible to suppress the non-uniformity of the light emitted from the light propagation member.

1 is a diagram schematically showing the configuration of a first example of a fluorescence microscope to which the present invention is applied; FIG. FIG. 4 is a diagram schematically showing how a condensing optical system condenses light from a light emitting element; The figure which shows typically the detail of the light-diffusion function by a diffusion plate. The figure which shows typically the structure of the 2nd example of the fluorescence microscope to which this invention is applied. FIG. 4 is a diagram schematically showing the relationship between the inclination of light with respect to the plane of incidence and the beam shape; The figure which shows the modification of a light emitting element typically. The figure which shows typically the structure of the 3rd example of the fluorescence microscope to which this invention is applied.

FIG. 1 is a diagram schematically showing the configuration of a first example of a fluorescence microscope to which the present invention is applied. In this figure and the following figures, XYZ orthogonal coordinates, which are composed of X, Y and Z directions which are orthogonal to each other, are shown as appropriate. A fluorescence microscope 1 in FIG. 1 irradiates a sample that fluoresces when irradiated with light L of a specific wavelength, and observes the fluorescence emitted from the sample. This fluorescence microscope 1 includes a sample stage 11 , an illumination optical system 13 , an observation optical system 15 and a controller 19 .

The sample table 11 has a sample surface 111 on which a sample is placed, the illumination optical system 13 irradiates the sample on the sample surface 111 with light L, and the observation optical system 15 emits fluorescence on the sample surface 111. Get a sample image. The control unit 19 has an arithmetic unit 191 configured by a processor or FPGA (Field Programmable Gate Array) or the like, and a storage unit 192 configured by an SSD (Solid State Drive) or HDD (Hard Disk Drive). The calculation unit 191 controls the irradiation of the light L from the illumination optical system 13 , and the image of the sample acquired by the observation optical system 15 is stored in the storage unit 192 .

A fluorescence microscope 1 includes a plurality of light-emitting elements 2 that emit light L, respectively. Specifically, four light emitting elements including two light emitting elements 2 arranged with a predetermined interval in the X direction and two light emitting elements 2 arranged with the predetermined interval in the Y direction. 2 is provided. These four light emitting elements 2 are circumferentially arranged at equal angular intervals around a virtual straight line parallel to the Z direction (in other words, when viewed from the Z direction). That is, N light-emitting elements 2 are arranged in N-fold symmetry with respect to the rotation operation about the virtual straight line (N is an integer of 2 or more, and is 4 in this example). Each light emitting element 2 is, for example, a laser diode, and emits laser light (light L) having a different wavelength by emitting light according to a drive signal supplied from the control section 19 .

The fluorescence microscope 1 also includes a plurality of condensing optical systems 3 arranged corresponding to the plurality of light emitting elements 2, respectively. Each condensing optical system 3 has a single or a plurality of lenses 31 and condenses the light L emitted from the corresponding light emitting element 2 . Corresponding to the arrangement of the plurality of light emitting elements 2 described above, the plurality of condensing optical systems 3 are arranged circumferentially (that is, N-fold symmetrical) at equal angular intervals. Therefore, the plurality of lights L emitted from each of the plurality of condensing optical systems 3 are condensed as shown in FIG.

FIG. 2 is a diagram schematically showing how the condensing optical system condenses the light from the light emitting element. FIG. 2 shows a plurality of lights L (luminous fluxes) respectively emitted from a plurality of condensing optical systems 3 . Each of the plurality of condensing optical systems 3 condenses the light L at a predetermined condensing position P. As shown in FIG. In addition, since the optical axis of each condensing optical system 3 is inclined with respect to the Z direction, the light L emitted from each condensing optical system 3 is inclined with respect to the Z direction and reaches the condensing position P. Incident.

The fluorescence microscope 1 also includes a diffuser plate 4 arranged with respect to the condensing position P of the condensing optical system 3 . The diffusion plate 4 is a flat plate having a surface perpendicular to the Z direction. Configurable. The diffusion plate 4 is arranged perpendicular to the Z direction (in other words, parallel to the X and Y directions), and the light L condensed at the condensing position P by the condensing optical system 3 passes through the diffusion plate 4. The light is diffused by the diffuser plate 4 while being transmitted.

Furthermore, the fluorescence microscope 1 includes a rod integrator 5 that propagates the light L diffused by the diffuser plate 4 . The rod integrator 5 has a rectangular parallelepiped or cylindrical shape extending in the Z direction, and has an incident surface 51 and an exit surface 52 at both ends in the Z direction. These entrance surface 51 and exit surface 52 are planes perpendicular to the Z direction. Furthermore, the rod integrator 5 has a side surface 53 extending between the entrance surface 51 and the exit surface 52 and parallel to the Z direction. An incident surface 51 of the rod integrator 5 faces the diffuser plate 4 from the opposite side of the condensing optical system 3 , and the light L transmitted through the diffuser plate 4 enters the incident surface 51 . The light L incident on the incident surface 51 propagates through the inside of the rod integrator 5 from the incident surface 51 toward the exit surface 52 and exits from the exit surface 52 . At this time, the light L incident on the side surface 53 of the rod integrator 5 propagates toward the exit surface 52 while being totally reflected by the side surface 53 .

The fluorescence microscope 1 also includes a condenser lens 61 and an objective lens 62 arranged on the exit surface 52 side of the rod integrator 5 in the Z direction. The condenser lens 61 faces the exit surface 52 of the rod integrator 5 and the objective lens 62 faces the sample surface 111 of the sample stage 11 . Therefore, the light L emitted from the exit surface 52 of the rod integrator 5 is condensed by the condenser lens 61 and projected onto the sample surface 111 by the objective lens 62 . The fluorescence microscope 1 also has a dichroic mirror 63 arranged between the condenser lens 61 and the objective lens 62 , and the light L traveling from the condenser lens 61 to the objective lens 62 passes through the dichroic mirror 63 .

When the sample on the sample surface 111 is irradiated with the light L, the sample is excited by the light L and fluoresces. The light L thus emitted from the sample passes through the objective lens 62 and is reflected by the dichroic mirror 63 . The fluorescence microscope 1 includes an imaging lens 64 arranged on the reflection side of the dichroic mirror 63 and an image sensor 7 . As the image sensor 7, a solid-state imaging device such as a CCD (Charge Coupled Device) or CMOS can be used. The light L reflected by the dichroic mirror 63 is imaged on the image sensor 7 by the imaging lens 64 . Thus, the image sensor 7 captures an image of the sample and transmits the image to the control section 19 .

Thus, in the example of FIG. 1, the illumination optical system 13 is composed of the condensing optical system 3, the diffusion plate 4, the rod integrator 5, the condenser lens 61 and the objective lens 62, and the objective lens 62, the dichroic mirror 63 and the imaging lens. 64 constitutes the observation optical system 15 .

Incidentally, the wavelength of the excited light differs depending on the sample. Therefore, the control unit 19 selectively gives a drive signal to one of the plurality of light emitting elements 2 that emits light of a wavelength corresponding to the sample, thereby causing the one light emitting element 2 to emit light. This allows the sample to be precisely excited.

FIG. 3 is a diagram schematically showing the details of the light diffusion function of the diffusion plate. Here, the function of the diffusing plate 4 will be described while appropriately showing the angular relationship between the light L, the diffusing plate 4 and the rod integrator 5 using FIG. Also, angles used in the description here are acute angles unless otherwise specified. Since the functions shown in FIG. 3 are common to a plurality of light-emitting elements 2 and a plurality of light-collecting optical systems 3, one light-emitting element 2 and one light-collecting element for condensing the light L from the one light-emitting element 2 are used. Description will be made using the optical system 3 .

FIG. 3 shows the upper limit ray Liu and the lower limit ray Lid of the incident light Li entering the diffusion plate 4 and the upper limit ray Lou and the lower limit ray Lod of the exiting light Lo emitted from the diffusion plate 4 . As shown in FIG. 3, the angle formed between the upper limit ray Lou and the lower limit ray Lod of the exiting light Lo is wider than the angle formed between the upper limit ray Liu and the lower limit ray Lid of the incident light Li. It fulfills the function of spreading the light L.

3 also shows a normal line NL that is perpendicular to the incident surface 51 of the rod integrator 5 and passes through the condensing position P. As shown in FIG. Since the incident surface 51 of the rod integrator 5 is a plane perpendicular to the Z direction, the normal NL is parallel to the Z direction. The principal ray Lm of the incident light Li is inclined by an angle θ with respect to the normal NL. Furthermore, both the upper limit ray Liu and the lower limit ray Lid of the incident light Li are inclined to the same side (downward in FIG. 3) with respect to the normal line NL, and the distance between the upper limit ray Liu and the lower limit ray Lid is , do not include rays whose angles with respect to the normal NL are zero degrees and near them.

Therefore, if the diffusion plate 4 is not provided and the light L is directly incident on the incident surface 51 of the rod integrator 5, the light L incident on the incident surface 51 does not include paraxial rays. Become. As a result, the light amount distribution of the light L emitted from the exit surface 52 becomes non-uniform with no component in the center. A diffusion plate 4 is provided in order to cope with this.

As shown in FIG. 3, the divergence angle θ _NA of the emitted light Lo (in other words, the angle between the lower limit ray Lod and the principal ray Lm) is the range including the normal NL (in other words, the angle with respect to the normal NL range including zero). That is, the following formula θ _NA −θ≧0 . . . central filling condition is satisfied. As a result, paraxial rays are included in the light L incident on the incident surface 51, and the central component in the light amount distribution of the light L emitted from the exit surface 52 can be secured. Incidentally, the angle formed by the upper limit ray Lou and the principal ray Lm also corresponds to the divergence angle θ _NA , and the emitted light Lo has a spread twice as large as the divergence angle θ _NA .

Furthermore, the divergence angle θ _NA of the emitted light Lo, the critical angle θ _C that gives the boundary of the angle at which the light L is totally reflected by the side surface 53 of the rod integrator 5, the refractive index n of the rod integrator 5, and the angle θ are: , the following equation: sin(θ _NA +θ)≦n×sin(90°−θ _C ) satisfies the total reflection condition. As a result, total reflection of the upper limit ray Lou on the side surface 53 is ensured, and the emergent light Lo can be reliably propagated from the incident surface 51 to the emergent surface 52 .

In the fluorescence microscope 1 described above, the light L (emitted light Lo) after being diffused by the diffusion plate 4 (light diffusion portion) propagates inside the rod integrator 5 (light propagation member). Therefore, the light L can be spread by the diffusion plate 4 and then propagated by the rod integrator 5 . Therefore, non-uniformity of the light L emitted from the rod integrator 5 can be suppressed.

Moreover, the rod integrator 5 has an incident surface 51 and an exit surface 52 and emits the light L incident from the incident surface 51 through the exit surface 52 . On the other hand, the diffusion plate 4 diffuses the light L between the condensing optical system 3 and the incident surface 51 . That is, the light L emitted by the condensing optical system 3 is incident on the incident surface 51 after being diffused by the diffusion plate 4 . In such a configuration, the diffuser plate 4 widens the divergence angle of the light L, the light L is made incident on the incident surface 51 of the diffuser plate 4 , and the light L can be propagated by the rod integrator 5 . Therefore, non-uniformity of the light L emitted from the exit surface 52 of the rod integrator 5 can be suppressed.

The incident surface 51 is a plane, and the principal ray Lm of the light L emitted by the condensing optical system 3 that condenses the light L from the light emitting element 2 is incline. In the fluorescence microscope 1 in which the principal ray Lm of the light L incident on the incident surface 51 is inclined with respect to the incident surface 51 as described above, the light L emitted from the exit surface 52 tends to be uneven. On the other hand, since the diffusion plate 4 is provided for diffusing the light L before entering the incident surface 51 , the influence of the inclination of the principal ray Lm of the light L with respect to the incident surface 51 is alleviated, and the rod integrator 5 Non-uniformity of the light L emitted from the exit surface 52 of can be suppressed.

In addition, as described above, the following equations sin(θ _NA +θ)≦n×sin(90°−θ _C ): total reflection condition θ _NA −θ≧0: center filling condition are satisfied. With such a configuration, the light L incident on the incident surface 51 of the rod integrator 5 can be ensured over an angle range including an angle parallel to the normal NL of the incident surface 51 of the rod integrator 5 (that is, zero degrees with respect to the normal NL). (Fig. 3). As a result, non-uniformity of the light L emitted from the exit surface 52 of the rod integrator 5 can be effectively suppressed.

A condenser lens 61 and an objective lens 62 (projection optical system) are provided to project the light L emitted from the exit surface 52 of the rod integrator 5 onto a sample surface 111 (arrangement surface) on which a sample (object) is arranged. It is With such a configuration, the light L whose non-uniformity is suppressed can be projected onto the sample surface 111 .

The fluorescence microscope 1 has a plurality of light emitting elements 2, and the light L emitted from each of the plurality of light emitting elements 2 is emitted from the condensing optical system 3 at different angles. In a configuration in which a plurality of light emitting elements 2 are arranged in this way, the light L emitted from each light emitting element 2 is incident on the rod integrator 5 at an angle, so that the light L emitted from the rod integrator 5 tends to be non-uniform. be. On the other hand, since the diffusion plate 4 for diffusing the light L is provided, the influence of the inclination of the light L can be alleviated, and the non-uniformity of the light L emitted from the rod integrator 5 can be suppressed. .

In addition, the plurality of light emitting elements emit light L with wavelengths different from each other. On the other hand, the control unit 19 causes one of the light emitting elements 2 selected from among the plurality of light emitting elements 2 to emit the light L. As shown in FIG. With such a configuration, the sample can be irradiated with light L having an appropriate wavelength to excite and fluoresce the sample.

FIG. 4 is a diagram schematically showing the configuration of a second example of a fluorescence microscope to which the present invention is applied. In the following, the description will focus on the parts that differ from the first example in FIG. 1, and the common parts will be denoted by corresponding reference numerals and the description thereof will be omitted as appropriate.

The second example differs from the first example in that a relay optical system 67 is arranged between the condenser lens 61 and the objective lens 62 . The relay optical system 67 includes an aperture stop 671 that narrows down the light L emitted from the condenser lens 61, a lens 672 that forms an intermediate image by forming an image of the light L that has passed through the aperture stop 671, a dichroic mirror 63, and an objective lens. and a lens 673 that projects the intermediate image onto the sample surface 111 through the lens 62 . The aperture stop 671 is arranged at the front focal point of the lens 672, and the image side of the lens 672 is telecentric. By providing the relay optical system 67 in this manner, it is possible to secure a space for arranging the dichroic mirror 63 while securing the illumination visual field and the numerical aperture.

By the way, in the above-described first and second examples, the light L is incident on the incident surface 51 at an angle. Such an inclination of the light L with respect to the incident surface 51 may distort the shape of the light L emitted from the exit surface 52 .

FIG. 5A is a diagram schematically showing the relationship between the inclination of light with respect to the plane of incidence and the beam shape. FIG. 5A shows Xe, Ye, and Ze directions that are orthogonal to each other provided for the light-emitting element 2 and the condensing optical system 3 . The Xe direction is parallel to the X direction, the Ye direction is tilted with respect to the Y direction, and the Ze direction is tilted with respect to the Z direction. This Ze direction is parallel to the optical axes of the light emitting element 2 and the condensing optical system 3 .

In FIG. 5A, the column of "beam shape before incidence" indicates the beam shape of the light L in the cross section before incidence Cb in the column of "illumination device", and the column of "beam shape after emission" indicates the shape of the light emitted from the column of "illumination device". The beam shape of the light L in the rear section Ca is shown. The pre-incidence cross section Cb is a cross section perpendicular to the Ze direction provided before incidence on the incidence surface 51 , and the post-ejection cross section Ca is a cross section perpendicular to the Z direction provided after emission from the emission surface 52 . As shown in the column "Beam shape before incidence", the light L at the cross section Cb before incidence has an isotropic circular shape, while at the cross section Ca after emission, as shown in the column "Beam shape after emission" is distorted to be short in the X direction and long in the Y direction. Therefore, the shape of the light L emitted from the light emitting element 2 may be configured as shown in FIG. 5B.

FIG. 5B is a diagram schematically showing a modification of the light emitting element. FIG. 5B also shows the Xe, Ye, and Ze directions. In this modification, the light emitting element 2 has different divergence angles in the Xe direction and the Ye direction, and the divergence angle in the Xe direction is larger than the divergence angle in the Ye direction. Therefore, as shown in the column of "beam shape before incidence", the light L at the cross section before incidence Cb has a width Wx in the Xe direction and a width Wy shorter than the width Wx in the Ye direction. As a result, the distortion of the light L at the post-emission cross section Ca is suppressed, as shown in the column "Beam shape after emission".

Thus, the light L emitted from the light emitting element 2 has a width Wy (first width) in the Ye direction (minor axis direction) and a width Wy in the Xe direction (major axis direction) orthogonal to the Ye direction. It has a longer width Wx (second width). At this time, the Ye direction is included in a plane (a YZ plane formed by the Y direction and the Z direction) including the principal ray Lm of the light L incident on the incident surface 51 and the normal line NL of the incident surface 51 . With such a configuration, the light L can be emitted isotropically from the exit surface 52 of the rod integrator 5 .

In the embodiment described above, the fluorescence microscope 1 corresponds to an example of the "microscope" of the present invention, and the light emitting element 2 and the illumination optical system 13 constitute an example of the "illumination device" of the present invention. corresponds to an example of the "observation optical system" of the present invention, the control section 19 corresponds to an example of the "control section" of the present invention, the light emitting element 2 corresponds to an example of the "light emitting element" of the present invention, and The light optical system 3 corresponds to an example of the "condensing optical system" of the present invention, the diffusion plate 4 corresponds to an example of the "light diffusion part" or the "diffusion plate" of the present invention, and the rod integrator 5 corresponds to an example of the "light diffusion part" or "diffusion plate" of the present invention. It corresponds to an example of a “light propagation member”, the incident surface 51 corresponds to an example of the “incident surface” of the present invention, the exit surface 52 corresponds to an example of the “exit surface” of the present invention, and the image sensor 7 corresponds to an example of the “exit surface” of the present invention. In the first example of the fluorescence microscope 1, the condenser lens 61, the objective lens 62 and the dichroic mirror 63 constitute an example of the "projection optical system" of the invention. In the second example, the condenser lens 61, the objective lens 62, the dichroic mirror 63, and the relay optical system 67 constitute an example of the "projection optical system" of the present invention, and the light L corresponds to an example of the "light" of the present invention. , the principal ray Lm corresponds to an example of the "principal ray" of the present invention, the normal line NL corresponds to an example of the "normal line" of the present invention, and the Xe direction corresponds to an example of the "long axis direction" of the present invention. The Ye direction corresponds to an example of the "minor axis direction" of the present invention, the width Wx corresponds to an example of the "second width" of the present invention, and the width Wy corresponds to the "first width" of the present invention. It corresponds to an example.

The present invention is not limited to the above-described embodiments, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, the configuration and arrangement of the diffusion plate 4 are not limited to the above examples, and can be changed as appropriate. Therefore, the fluorescence microscope 1 may be configured as shown in FIG. 6 below.

FIG. 6 is a diagram schematically showing the configuration of a third example of a fluorescence microscope to which the present invention is applied. In the following, the explanation will focus on the parts that are different from the above example, and the common parts will be given corresponding reference numerals and their explanation will be omitted as appropriate. In the third example of FIG. 6, a diffusion layer 41 is formed on the end surface of the rod integrator 5 on the side of the condensing optical system 3 . The diffusion layer 41 can be configured by, for example, providing a fine uneven shape or providing a fine lens array. The diffusion layer 41 exhibits a light diffusion function like the diffusion plate 4 described above. In the rod integrator 5 , the interface of the diffusion layer 41 functions as an incident surface 51 , and the light L diffused by the diffusion layer 41 enters the incident surface 51 and then propagates inside the rod integrator 5 .

In the fluorescence microscope 1 of FIG. 6, the light L (exiting light Lo) after being diffused by the diffusion layer 41 (light diffusion portion) propagates inside the rod integrator 5 (light propagation member). Therefore, the light L can be spread by the diffusion layer 41 and then propagated by the rod integrator 5 . Therefore, non-uniformity of the light L emitted from the rod integrator 5 can be suppressed.

Also, the arrangement and the number of the light emitting elements 2 may be changed as appropriate. For example, the arrangement of the plurality of light emitting elements 2 is not limited to the above example, and does not need to have rotational symmetry. Alternatively, the number of light emitting elements 2 is not limited to four, and may be one to three or five or more. At this time, it is preferable to change the arrangement and the number of the condensing optical systems 3 according to the arrangement and the number of the light-emitting elements 2 .

Also, the configuration of the condensing optical system 3 may be modified. That is, in the above example, the condensing optical system 3 is individually provided for each of the plurality of light emitting elements 2 . However, a common condensing optical system 3 is arranged for the plurality of light emitting elements 2, and the light L from each light emitting element 2 is condensed at the condensing position P by the condensing optical system 3. good too.

Also, the condensing position P may be changed. For example, the condensing positions P of the plurality of condensing optical systems 3 do not need to match, and may be slightly deviated. Also, the condensing position P may be slightly deviated from the diffuser plate 4 .

Also, it is not essential to satisfy the center filling condition or the total reflection condition described above. Even if any of the conditions are not satisfied, the light L is diffused by the diffusion plate 4 or the diffusion layer 41, thereby suppressing non-uniformity of the light L emitted from the rod integrator 5. can do.

Also, an example of the “light propagation member” is not limited to the rod integrator 5. Therefore, an optical fiber may be used instead of the rod integrator 5. FIG.

The fluorescence microscope 1 may also have a function of irradiating a sample with white light and observing the sample.

Further, the application target of the illumination device described above is not limited to the fluorescence microscope 1, but can also be applied to an exposure device that exposes an exposure target.

INDUSTRIAL APPLICABILITY The present invention can be applied to general illumination techniques for irradiating light on an object.

1... Fluorescence microscope (microscope)
13... Illumination optical system (illumination device)
DESCRIPTION OF SYMBOLS 15... Observation optical system 19... Control part 2... Light emitting element (illumination device)
3... Condensing optical system 4... Diffusion plate (light diffusion part)
5... Rod integrator (light propagation member)
51... Entrance surface 52... Exit surface 61... Condenser lens (projection optical system)
62 ... objective lens (projection optical system)
63... Dichroic mirror (projection optical system)
67... Relay optical system (projection optical system)
7 ... Image sensor (sensor)
L... light Lm... chief ray NL... normal line Xe... Xe direction (long axis direction)
Ye...Ye direction (minor axis direction)
Wx ... width (second width)
Wy: width (first width)

Claims (14)

a light-emitting element that emits light;
a condensing optical system that collects and emits the light emitted from the light emitting element;
a light diffusing section that diffuses the light emitted from the condensing optical system;
and a light propagating member that propagates the light diffused by the light diffusing section. The light propagation member has an incident surface and an exit surface, and emits light incident from the incident surface from the exit surface,
The light diffusion unit diffuses light between the condensing optical system and the incident surface,
2. The lighting device according to claim 1, wherein the light emitted by the condensing optical system is incident on the incident surface after being diffused by the light diffusing section. the plane of incidence is a plane,
3. The illumination device according to claim 2, wherein a principal ray of light emitted from said light emitting element and then emitted by said condensing optical system is inclined with respect to a normal line perpendicular to said incident surface. an angle θ between a principal ray of light emitted from the condensing optical system and the normal line, a divergence angle θ _NA of the light diffused by the light diffusion section, and a refractive index n of the light propagation member; , and the critical angle θ _C of light propagating inside the light propagating member from the incident surface toward the exit surface is defined by the following formula: sin(θ _NA +θ)≦n×sin(90°−θ _C )
θ _NA −θ≧0
4. The lighting device according to claim 3, wherein: The light emitted from the light emitting element has a first width in a minor axis direction and a second width longer than the first width in a major axis direction different from the minor axis direction,
5. The illumination device according to claim 3, wherein the minor axis direction is included in a plane including the principal ray of light incident on the incident surface and the normal line. 6. The illumination device according to any one of claims 2 to 5, further comprising a projection optical system that projects the light emitted from the exit surface onto an arrangement surface on which an object is arranged. The lighting device according to any one of claims 1 to 6, wherein the light propagation member is a rod integrator. The lighting device according to any one of claims 1 to 7, wherein the light emitting element is a laser diode. Each of a plurality of light emitting elements is arranged as the light emitting element,
The lighting device according to any one of claims 1 to 8, wherein the light emitted from each of the plurality of light emitting elements is emitted from the condensing optical system at different angles. further comprising a control unit that controls emission of light from the plurality of light emitting elements,
the plurality of light emitting elements emit light of different wavelengths;
10. The lighting device according to claim 9, wherein the control unit causes one light emitting element selected from among the plurality of light emitting elements to emit light. 11. The lighting system according to any one of claims 1 to 10, wherein the light diffusing part is a diffuser plate provided between the condensing optical system and the light propagating member and spaced apart from the light propagating member. Device. The lighting device according to any one of claims 1 to 10, wherein the light diffusing portion is provided on an end surface of the light propagating member. a lighting device according to any one of claims 1 to 12;
a sensor that detects light;
and an observation optical system for irradiating the sensor with light emitted from an object in response to irradiation of light from the illumination device. a step of emitting light emitted from the light emitting element while concentrating it with a condensing optical system;
a step of diffusing the light emitted from the condensing optical system with a light diffusing section;
and a step of propagating the light diffused by the light diffusing part with a light propagating member.

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