JP2011209441A - Microscope illuminator and microscope equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact illuminator that has a low-cost, satisfactory illuminating performance, and to provide a microscope.SOLUTION: The microscope illuminator includes: a light source 11 including a solid-state light emitting element for emitting illuminating light; and an illuminating optical system including, in order from the light source 11, a collector lens 12 for condensing illuminating light and a condenser lens 14 for emitting illuminating light to a specimen 3. At this time, the effective diameter of a first optical face, which is the optical face 12b of the specimen 3 side of the collector lens 12, is 1.35 or more times as large as a distance between the light source 11 and the first optical face.

Description

  The present invention relates to a microscope illumination device and a microscope including the same.

  In the field of microscopes, the most common method for focusing on a specimen is to displace the stage on which the specimen is placed up and down. Such a configuration (hereinafter referred to as a stage displacement type configuration) is disclosed in Patent Document 1, for example. However, in the stage displacement type configuration, since the specimen is displaced together with the stage, the height from the desk surface to the specimen is not constant. This increases the burden on the observer and becomes a factor of deteriorating workability for sample exchange and the like.

  Further, in the stage displacement type configuration, there are many configurations in which the condenser lens is fixed to the stage. In this case, the distance from the light source to the condenser lens also changes due to the displacement of the stage. In order to realize good illumination independent of the position of the stage, it is required that a sufficient amount of light can be ensured up to the periphery of the field of view even when the condenser lens is located farthest from the light source. This increases the effective diameter of the optical element on the illumination optical path including the condenser lens.

  On the other hand, as another method for focusing on the specimen, there is a method in which the stage is fixed and the revolver to which the objective lens is attached is displaced up and down instead. Such a configuration (hereinafter referred to as a revolver displacement type configuration) is disclosed in Patent Document 2, for example. The revolver displacement type configuration is preferable because the height of the stage and the optical path length from the light source to the condenser lens are constant. Even in the revolver displacement type configuration, if the stage height is high, the operability is not sufficiently improved. For this reason, it is desirable that the light source to the condenser lens be compact.

Japanese Patent No. 3650265 JP 2001-228408 A

By the way, high-resolution observation with a microscope requires a high numerical aperture for both the observation optical system and the illumination optical system. That is, a large spherical aberration also occurs in the illumination optical system, and an aspherical surface having a large curvature is required for the correction. Such an aspheric surface is usually provided in the collector lens. Therefore, the thickness of the collector lens is increased, and the entire length of the illumination device including the light source is increased.
As described above, in the conventional illumination device for a microscope, the compactness and high performance of the illumination device are contradictory, and it is difficult to achieve both of them.

In addition, a tungsten lamp, a halogen lamp, or the like is used as a light source of an illumination device for a microscope. The use of these light sources is accompanied by a large amount of heat when light is emitted while sufficient illumination is achieved. For this reason, an illumination optical system, particularly a collector lens close to the light source, needs to be subjected to a heat-resistant treatment that reduces the influence of heat, and the use of such a light source increases the cost of the illumination device.
In light of the above circumstances, an object of the present invention is to provide a low-cost and compact illumination device and microscope.

  A first aspect of the present invention includes a light source composed of a solid-state light emitting element that emits illumination light, a collector lens that collects illumination light in order from the light source side, and a condenser lens that irradiates the specimen with illumination light. An illumination optical system, and the effective diameter of the first optical surface, which is an optical surface on the specimen side of the collector lens, is 1.35 times or more the distance between the light source and the first optical surface Providing equipment.

According to a second aspect of the present invention, in the microscope illumination apparatus according to the first aspect, the collector lens includes a plurality of lenses, and the first optical surface is the optical surface on the specimen side of the lens closest to the light source. An illumination device for a microscope is provided.
According to a third aspect of the present invention, there is provided the microscope illumination apparatus according to the first aspect or the second aspect, wherein the first optical surface is an aspherical surface.

  According to a fourth aspect of the present invention, there is provided the microscope illumination apparatus according to any one of the first to third aspects, wherein the collector lens is a Fresnel lens.

  According to a fifth aspect of the present invention, there is provided the microscope illumination device according to any one of the first to fourth aspects, wherein the collector lens material is resin or silicone rubber. To do.

According to a sixth aspect of the present invention, in the microscope illumination device according to any one of the first to fifth aspects, an aperture stop is further provided between the collector lens and the condenser lens, and the condenser lens is provided. Is a sample side numerical aperture of the illumination optical system, NA is a radius of the maximum illumination range of the sample by the illumination optical system, and L is a distance from the aperture stop to the first optical surface. Then, the following conditional expression L ≦ (NA × f ² ) / h (1)
Provided is a microscope illumination device that satisfies the above requirements.

  According to a seventh aspect of the present invention, in the microscope illumination device according to any one of the first to sixth aspects, the collector lens includes a diffuser that diffuses illumination light inside the lens of the collector lens. An illumination device for a microscope is provided.

  According to an eighth aspect of the present invention, in the microscope illumination device according to any one of the first to sixth aspects, the collector lens has a diffusion pattern that diffuses illumination light on the optical surface of the collector lens. A microscope illumination device is provided.

  According to a ninth aspect of the present invention, there is provided the microscope illumination apparatus according to any one of the first to eighth aspects, wherein the solid-state light emitting element is a light emitting diode.

According to a tenth aspect of the present invention, there is provided the microscope illumination apparatus according to any one of the first to eighth aspects, wherein the solid-state light emitting element is an organic electroluminescence element. .
An eleventh aspect of the present invention provides a microscope including the microscope illumination apparatus according to any one of the first to tenth aspects.

According to a twelfth aspect of the present invention, the microscope according to the eleventh aspect further includes a stage on which the specimen is arranged, an objective lens for observing the specimen, and a revolver to which the objective lens is attached. A microscope is provided that adjusts the distance between the specimen and the objective lens by displacing the lens.

  According to the present invention, it is possible to provide a low-cost and compact illumination device and microscope.

It is the figure which illustrated the composition of the microscope concerning one embodiment of the present invention. It is the figure which illustrated the structure of the illuminating device which concerns on one Embodiment of this invention. It is the figure which illustrated the structure of the conventional illuminating device. It is a figure for demonstrating the Fresnel lens which concerns on one Embodiment of this invention. It is a light ray diagram which illustrated a light ray of an illuminating device when an objective lens is 4 times. It is a light ray diagram which illustrated a light ray of an illuminating device when an objective lens is 10 times. It is a light ray diagram which illustrated a light ray of an illuminating device when an objective lens is 40 times. It is a light ray diagram which illustrated a light ray of an illuminating device when an objective lens is 100 times. It is a figure for demonstrating the effective diameter required for the collector lens which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating the configuration of a microscope according to an embodiment of the invention. A microscope 100 according to the present embodiment includes a base 1 in contact with a desk surface, a stage 2 on which a specimen 3 is arranged, an objective lens 4 for observing the specimen 3, a revolver 5 to which the objective lens 4 is attached, and a base 1 1 includes a frame 7 supported by a support column 6, a lens barrel 8, an eyepiece lens 9, and an illumination device 10 that illuminates the specimen 3.

The revolver 5 includes a focusing mechanism (not shown) and is configured to be movable up and down. The microscope 100 can adjust the distance between the specimen 3 and the objective lens 4 by displacing the objective lens 4 together with the revolver 5 in the optical axis direction, and can focus on the specimen 3.
The illumination device 10 is arranged in the base 1 and is configured as a transmission illumination device that illuminates the specimen 3 from below.

  Next, the illumination device included in the microscope will be described in more detail. FIG. 2A is a diagram illustrating the configuration of the illumination device 10 of this embodiment illustrated in FIG. 1. Moreover, FIG. 2B is the figure illustrated about the structure of the conventional illuminating device.

  The illumination device 10 illustrated in FIG. 2A includes a light source 11 that emits illumination light and an illumination optical system. The illumination optical system includes, in order from the light source 11 side, a collector lens 12 that collects illumination light, an aperture stop 13 that adjusts the brightness for illuminating the sample, and a condenser lens 14 that irradiates the sample 3 with illumination light. It is configured to include.

  FIG. 2A shows an example in which Koehler illumination is realized. That is, in the illumination device 10, the aperture stop 13 is provided at the front focal position of the condenser lens 14, and the light source image 15 is projected onto the aperture stop 13.

The illuminating device 20 illustrated in FIG. 2B includes the same components as the illuminating device 10 illustrated in FIG. 2A. Specifically, in order from the light source 21 side, a light source 21 that emits illumination light, a collector lens 22 that collects the illumination light, and an aperture stop 2 that adjusts the brightness to illuminate the specimen.
3 and a condenser lens 24 that irradiates the specimen 3 with illumination light. FIG. 2B also shows an example in which Koehler illumination is realized.

  The light source 11 of the illuminating device 10 according to the present embodiment is composed of a solid-state light emitting element that generates less heat as illumination light is emitted. The solid light emitting element is, for example, a light emitting diode or an organic electroluminescence element (hereinafter referred to as an organic EL element).

  On the other hand, the light source 21 of the illuminating device 20 is composed of a lamp light source using a filament that generates a lot of heat as the illumination light is emitted. The lamp light source is, for example, a halogen lamp or a tungsten lamp.

  As described above, the lighting device 10 can be configured such that the distance from the light source 11 to the collector lens 12 is shorter than that of the lighting device 20 by using a solid-state light emitting element that generates less heat for the light source 11. For this reason, the effective diameter of the collector lens 12 can also be made smaller than the effective diameter of the collector lens 22. Accordingly, the distance from the collector lens 12 to the aperture stop 13 is shortened, and the overall length of the illumination optical system can be shortened. As a result, as illustrated in FIGS. 2A and 2B, the overall length of the illumination device 10 is shorter than the overall length of the conventional illumination device 20, and the illumination device 10 can be configured compactly.

  Further, in order to ensure good illumination performance of the illumination device 10, the taking-in angle of the collector lens 12 is also important. For this reason, it is desirable that the effective diameter of the collector lens 12 be larger than the total length of the light source 11 and the collector lens 12. Specifically, the effective diameter of the collector lens 12 is desirably 1.35 times or more the total length of the light source 11 and the collector lens 12 in consideration of the light distribution angle characteristic of the solid light emitting element and the amount of emitted light. The total length of the light source 11 and the collector lens 12 is more strictly the distance from the light source 11 to the sample-side optical surface 12b (first optical surface) of the collector lens 12. When the collector lens 12 is composed of a plurality of lenses, the first optical surface is the most sample-side optical surface of the collector lenses 12, and the distance is the largest of the light sources 11 to the collector lenses 12. The distance to the optical surface on the specimen side.

  In the illumination device 10, since the distance from the light source 11 to the collector lens 12 is short, the outer diameter of the collector lens 12 is relatively large even when the effective diameter is large with respect to the total length of the light source 11 and the collector lens 12. It can be kept small. In other words, both the total length of the light source 11 and the collector lens 12 (that is, the length in the optical axis direction) and the outer diameter of the collector lens 12 (that is, the length in the direction perpendicular to the optical axis) are reduced to make the illumination device 10 compact. In this way, good lighting performance can be realized.

Moreover, since the illuminating device 10 uses a solid-state light emitting element that generates little heat as the light source 11, it is not necessary to subject the collector lens 12 to heat treatment. Thereby, compared with the conventional illuminating device 20, the illuminating device 10 can be manufactured at low cost. In addition, a solid-state light emitting element consumes less power and has a longer life than a lamp light source such as a halogen lamp. For this reason, in the illuminating device 10, in addition to a manufacturing cost, an operating cost can also be reduced.
As described above, it is possible to provide a compact illumination device and a microscope with favorable illumination performance at low cost.
Hereinafter, the further preferable structure of the illuminating device 10 of this embodiment is demonstrated.

The collector lens 12 of the illumination device 10 preferably has an aspherical surface. The collector lens 12 takes in the illumination light emitted from the light source 11 with a strong power and emits it as substantially parallel light. For this reason, the optical surface constituting the collector lens 12 requires a large curvature. A large spherical aberration occurs on an optical surface with a large curvature, but spherical aberration can be favorably corrected by configuring at least one surface of the collector lens 12 as an aspherical surface. The aspherical surface is preferably an optical surface on the specimen side of the collector lens 12.

  The collector lens 12 of the illumination device 10 is preferably configured as a Fresnel lens. FIG. 3 is a diagram for explaining the characteristics of the Fresnel lens. The convex lens 16 which consists of the plane 16a and the convex surface 16b, and the Fresnel lens 17 which consists of the plane 17a and the Fresnel surface 17b are illustrated. The curvature of the convex surface 16b and the curvature of the Fresnel surface 17b are the same, and the convex lens 16 and the Fresnel lens 17 have the same power.

  Since the collector lens 12 usually requires a large power and requires an optical surface with a large curvature, the thickness of the lens also increases. However, as illustrated in FIG. 3, the thickness of the lens can be reduced by configuring the collector lens 12 having the same curvature and the same power as the optical surface as a Fresnel lens. Moreover, if the collector lens 12 is thin, the light source 11 can be brought closer. Thereby, an illuminating device can be comprised further compactly.

  In addition, it is desirable for the Fresnel lens to disperse power on both sides. As illustrated in FIG. 3, an optical surface having a certain curvature has a steeper slope as it is closer to the end of the lens. Dispersing power on both sides reduces the curvature of each side and facilitates processing of the Fresnel surface. For this reason, the workability of the Fresnel lens is improved. Further, it is desirable that the Fresnel lens is configured with both surfaces as Fresnel surfaces. Thereby, the thickness of the lens can be further reduced.

  The material of the collector lens 12 is preferably a resin material or silicone rubber. As the resin material, for example, a polycarbonate resin, an acrylic resin, ZEONEX (trade name of Nippon Zeon Co., Ltd.) or the like may be used. By using a resin material or silicone rubber, lens molding using a mold becomes possible. Thereby, compared with the case where a glass material is used, manufacturing cost can be reduced. In addition, with resin materials and silicone rubber, it is easy to mold a Fresnel surface or an aspherical surface with high accuracy. For this reason, a manufacturing error is suppressed small and illumination performance is also stabilized.

  The collector lens 12 desirably has a diffusion pattern for diffusing illumination light on the optical surface of the collector lens 12. Usually, a diffusion plate is disposed in the optical path in order to suppress variation in luminance of the illumination light. However, the diffusion plate can be omitted by providing a diffusion pattern on the collector lens 12. For this reason, the number of parts is reduced and the space for arranging the diffusion plate is saved. Thereby, it is possible to configure the illumination device at a lower cost and more compactly while ensuring the uniformity of illumination. In particular, when a resin material or silicone rubber is used, a lens having a diffusion pattern can be easily formed by providing a diffusion pattern in the mold.

  Further, the collector lens 12 may be configured by providing a diffuser that diffuses illumination light inside the collector lens instead of the diffusion pattern. When the collector lens 12 is formed as a Fresnel lens, a diffusion plate may be provided on an optical surface that is not the Fresnel lens surface. In this case as well, the same effect as when the diffusion pattern is provided can be obtained.

Furthermore, it is desirable that the effective diameter of the collector lens 12 should not be larger than the effective diameter necessary for ensuring good illumination performance. As described above, by making the effective diameter of the collector lens 12 larger than the total length of the light source 11 and the collector lens 12, the light capture angle can be increased and a large amount of light can be secured. However, if the effective diameter of the collector lens 12 is too large, the illumination optical system becomes large. In addition, on an optical surface having a certain curvature, the inclination becomes steeper as it is closer to the end of the lens. When the collector lens 12 is a Fresnel lens, it is difficult to form a Fresnel surface with a steep slope. However, if the effective diameter is too large, the end of the lens must be used, and the processing of the collector lens 12 becomes extremely difficult. . For this reason, it is desirable not to make the effective diameter of the collector lens 12 unnecessarily large and not to use the end of the lens with a steep inclination. This also reduces the manufacturing error of the Fresnel lens and stabilizes the illumination performance. In addition, the yield is improved, which contributes to cost reduction.

  Note that the effective diameter necessary to ensure good illumination performance depends on the numerical aperture and illumination range. 4A, 4B, 4C, and 4D show the marginal rays on the axis of the illumination device 10 when the magnification of the objective lens 4 of the microscope 100 is 4, 10, 40, and 100 times, respectively. It is the illustrated light ray diagram. As illustrated in FIGS. 4A to 4D, in combination with a high-magnification objective lens 4 (for example, see FIG. 4D), the beam diameter is large, and although not shown, optical paths of on-axis and off-axis light beams Is not much different. For this reason, the effective diameter required for the collector lens 12 can be approximated by the width between the marginal rays on the axis. On the other hand, in the combination with the low-magnification objective lens 4, the optical paths of the on-axis and off-axis light beams are greatly different. For this reason, the effective diameter required for the collector lens 12 cannot be approximated by the optical path of the light beam on the axis. It is necessary to determine based on the position where the off-axis ray passes through the collector lens 12. However, in the case of low magnification (see, for example, FIG. 4A), since the light beam diameter is thin, the effective diameter can be determined based on the off-axis principal ray.

  4A to 4D show examples in which the diffusion plate 12d is disposed between the aperture stop 13 and the collector lens 12. FIG. As already described above, the collector lens 12 itself serves as a diffusion plate, so that the diffusion plate 12d can be omitted.

  FIG. 5 is a diagram for explaining in more detail the effective diameter necessary for the collector lens 12 in order to ensure good illumination performance. FIG. 5 illustrates the illumination device 10 in which the aperture stop 13 is disposed at the front focal position of the condenser lens 14 and the sample 3 is disposed at the rear focal position. FIG. 5 also schematically shows a marginal ray 18 on the axis that determines the numerical aperture and a principal ray 19 that is off-axis that determines the maximum illumination range.

  First, an on-axis marginal ray 18 is traced from the specimen 3 toward the light source 11. The marginal ray 18 is converted parallel to the optical axis by the condenser lens 14, passes through the aperture stop 13, and enters the collector lens 12. At this time, the pupil diameter of the illumination optical system is expressed by 2 × f × NA using the focal length f of the condenser lens 14 and the numerical aperture NA on the sample 3 side of the illumination optical system. As illustrated in FIG. 5, assuming that the marginal ray 18 is parallel to the optical axis between the condenser lens 14 and the collector lens 12, the marginal ray 18 that determines the numerical aperture causes the collector lens 12 to be f from the optical axis. Passes a position separated by × NA. That is, the effective diameter of the collector lens 12 necessary for securing the numerical aperture NA on the specimen 3 side is expressed by 2 × f × NA.

  Next, the principal ray 19 which is the most off-axis is traced from the specimen 3 toward the light source 11. Assuming Koehler illumination, the principal ray 19 enters the condenser lens 14 in parallel, and intersects the optical axis at a position away from the condenser lens 14 by the focal length f. Then, the light passes through the optical axis at the same angle and enters the collector lens 12. At this time, the right triangle A composed of the optical axis, the condenser lens 14, and the principal ray 19 has a height h / 2 of the maximum illumination range and a base side of the focal length f of the collector lens 12.

On the other hand, a right triangle B composed of the optical axis, the collector lens 12 and the principal ray 19 is similar to the right triangle A. Therefore, if the base of the right triangle B is the distance L from the aperture stop 13 to the first optical surface of the collector lens 12, the height of the right triangle B is (h × L) / (2 × f). expressed. Therefore, the principal ray 19 that determines the maximum illumination range passes through the collector lens 12 at a position away from the optical axis by (h × L) / (2 × f). That is, the effective diameter of the collector lens 12 necessary for ensuring the maximum illumination range h is represented by (h × L) / f.

  As described above, the effective diameter of the collector lens 12 for securing the numerical aperture is constant with respect to the focal length f of the collector lens 12. On the other hand, the effective diameter of the collector lens 12 for ensuring the maximum illumination range is not determined only by the focal length f of the collector lens 12, but the distance L from the aperture stop 13 to the first optical surface of the collector lens 12. Also depends on.

For this reason, in the illuminating device, it is desirable to adjust the distance L to suppress the effective diameter of the collector lens 12 for securing the maximum illumination range within the effective diameter of the collector lens 12 for securing the numerical aperture. More specifically, the lighting device preferably satisfies the following conditional expression (1). Where f is the focal length of the condenser lens 14, NA is the numerical aperture on the specimen side of the illumination optical system, h is the radius of the maximum illumination range of the specimen by the illumination optical system, and L is the aperture This is the distance from the diaphragm 13 to the first optical surface of the collector lens 12.
L ≦ (NA × f ² ) / h (1)

  By satisfying conditional expression (1), it is possible to minimize the effective diameter of the collector lens 12 necessary to achieve both the numerical aperture and the illumination range. Thereby, the illuminating device which implement | achieves favorable illumination performance can be comprised further compactly. Further, even when the collector lens 12 is configured as a Fresnel lens, the workability of the Fresnel lens can be maintained well without excessively difficult processing of the Fresnel surface.

DESCRIPTION OF SYMBOLS 100 Microscope 1 ... Base 2 ... Stage 3 ... Specimen 4 ... Objective lens 5 ... Revolver 6 ... Revolver 7 ... Frame 8 ... Lens tube 9 ... Eyepiece 10, 20 ... Illumination devices 11, 21 ... Light sources 12, 22 ... Collector lenses 12a, 12b ... Optical surfaces 13, 23 ... Aperture stops 14, 24 ... Condenser lenses 15, 25 ... Light source image 16 ... Convex lens 17 ... Fresnel lenses 16a, 17a ... Plane 16b ... Convex surface 17b ... Fresnel surface 18 ... Marginal ray 19 ... Main rays A, B .. Right triangle

Claims (12)

A light source composed of a solid-state light emitting element that emits illumination light;
In order from the light source side, including a collector lens that collects the illumination light, and a condenser lens that irradiates the specimen with the illumination light, and an illumination optical system,
The effective diameter of the first optical surface, which is the sample-side optical surface of the collector lens, is 1.35 times or more the distance between the light source and the first optical surface. Lighting device. The microscope illumination device according to claim 1,
The collector lens includes a plurality of lenses,
The microscope illumination apparatus, wherein the first optical surface is an optical surface on the specimen side of the lens closest to the light source. In the illumination device for microscopes of Claim 1 or Claim 2,
The illumination device for a microscope, wherein the first optical surface is an aspherical surface. In the illuminating device for microscopes of any one of Claim 1 thru | or 3,
The microscope illumination apparatus, wherein the collector lens is a Fresnel lens. The microscope illumination apparatus according to any one of claims 1 to 4,
The microscope illumination device is characterized in that the material of the collector lens is resin or silicone rubber. The microscope illumination device according to any one of claims 1 to 5, further comprising:
An aperture stop is included between the collector lens and the condenser lens,
The focal length of the condenser lens is f, the numerical aperture on the sample side of the illumination optical system is NA, the radius of the maximum illumination range of the sample by the illumination optical system is h, and the first aperture from the aperture stop When the distance to the optical surface is L, the following conditional expression L ≦ (NA × f ² ) / h (1)
A microscope illumination device characterized by satisfying the above. The microscope illumination device according to any one of claims 1 to 6,
The microscope illumination apparatus according to claim 1, wherein the collector lens includes a diffuser that diffuses the illumination light inside the collector lens. The microscope illumination device according to any one of claims 1 to 6,
The microscope illumination device, wherein the collector lens has a diffusion pattern for diffusing the illumination light on an optical surface of the collector lens. The microscope illumination device according to any one of claims 1 to 8,
The microscope illumination apparatus, wherein the solid-state light emitting element is a light emitting diode. The microscope illumination device according to any one of claims 1 to 8,
The microscope illumination apparatus, wherein the solid-state light emitting element is an organic electroluminescence element.   A microscope comprising the illumination device for a microscope according to any one of claims 1 to 10. The microscope according to claim 11, further comprising:
A stage for placing the specimen;
An objective lens for observing the specimen;
A revolver to which the objective lens is attached,
A microscope characterized by adjusting a distance between the specimen and the objective lens by displacing the objective lens.