JP2010217473A - Lighting system and microscope including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system and a microscope equipped with the same having sufficient brightness and a wide irradiation field and allowing at least one of dark field illumination and focal illumination while achieving miniaturization of the system. <P>SOLUTION: A dark field illumination apparatus 10 includes a light source 11, which consists of a plurality of light emitting diodes located in the hollow heptagonal shape around the observation optical axis X perpendicular to a specimen face 31a, and a reflection member 12, which consists of mirrors 12a-12g reflecting illumination light emitted from the light source 11, below the specimen face 31a. The illumination light is radiated from the diagonal lower side of the specimen face 31a via the reflection member 12 at least once. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illumination device capable of at least one of dark field illumination and oblique illumination, and a microscope including the illumination device.

  2. Description of the Related Art Conventionally, in a lighting apparatus used for a stereomicroscope or the like, transmitted illumination is often used for observing a living specimen alive or performing an inspection in a semiconductor device process. Such illumination devices are selectively used for bright field observation and dark field observation depending on applications, and there are a wide variety of illumination light sources used for these.

  For example, there is one that uses a lamp such as halogen or tungsten as an illumination light source and performs illumination within the field of view of the stereomicroscope through a lens or a reflector. In this case, place the lamp directly under the specimen facing the stereomicroscope body, or place a mirror directly under the specimen and place the light from the lamp on the optical axis bent by the mirror. ing. In addition, there is an optical fiber used for introducing light from a lamp.

  However, in general, the magnification of a stereomicroscope is lower than that of an ordinary microscope and the field of view is wide, so the illumination range must be widened. For this reason, when the lamp is placed directly under the specimen, if the illumination of the required field of view is performed with a reflector or lens, the distance from the desk to the specimen increases, and the optical axis is folded using a mirror. Similarly, since the required beam diameter is increased, the distance from the desk to the sample is increased. This is because the specimen is positioned higher than the desk surface. For example, when changing the specimen, the movement of the observer's hand must be increased up and down between the desk surface and the stage. There was a problem that it was difficult to perform the work while observing the specimen. In addition, lamps such as halogen and tungsten used as an illumination light source have a problem that they generate a large amount of heat and consume power and have a short life.

  Therefore, as a means for solving the problem caused by using such a lamp, there is a method using a plurality of light emitting diodes as a light source (see, for example, Patent Document 1 and Patent Document 2).

JP 2003-75725 A JP 2006-209035 A

  However, the spread angle of a light beam emitted from a light emitting diode (hereinafter referred to as LED) used as a light source is limited. Therefore, in the conventional illumination device, in order to widen the irradiation range of the LED, it is necessary to make the optical path length to the light source and the specimen surface as long as possible, which leads to an increase in the size of the illumination device (particularly in the thickness direction).

  Moreover, in the illuminating device described in Patent Document 1, the angle at which the sample surface is illuminated by the LED used for dark field illumination is constant. Therefore, when an objective lens having a large numerical aperture is used, direct light may enter the objective lens and cause flare. On the other hand, if the illumination angle is increased in order to prevent such a phenomenon, the rate at which light is reflected by the stage glass increases. Therefore, when an objective lens having a small numerical aperture is used, the illumination becomes darker than necessary. .

  Moreover, in the illuminating device described in Patent Document 2, although the above-mentioned problem has been solved by making the illumination angle variable, it is necessary to arrange each LED on a separate substrate, which is costly. End up. If a flexible substrate is used, a plurality of LEDs can be arranged on one substrate, but an increase in cost is unavoidable.

  Further, in the illumination device described in Example 9 of Patent Document 2, individual LEDs are arranged circumferentially so as to direct the light beam from the light source toward the sample surface parallel to the observation optical axis orthogonal to the sample surface. Then, the sample surface is illuminated by reflecting the light flux from each LED with a mirror. In this case, it is possible to arrange a plurality of LEDs circumferentially on one substrate, but the distance from the sample surface to the LEDs becomes longer, and the thickness of the illumination device increases. Therefore, if the distance between the observation optical axis and the optical axis of the LED is shortened, the thickness of the apparatus can be suppressed. However, since the circumference of the LED is shortened, the number of LEDs that can be arranged is small. Decreases and the lighting becomes dark.

  In the illumination device described in Patent Document 2, when the illumination angle is changed, the distance from the light source to the sample surface is not optimized, and if the illumination angle is reduced, the center of the sample becomes darker. When the illumination angle is increased, the illumination field becomes smaller.

  The present invention has been made in view of such a problem, and has a sufficient brightness and a wide illumination field, and can perform at least one of dark field illumination and oblique illumination while reducing the size of the apparatus. An object is to provide an apparatus and a microscope including the same.

  In order to achieve such an object, the present invention provides an illumination device for a microscope capable of at least one of dark field illumination and oblique illumination, wherein an observation optical axis perpendicular to the sample surface is provided below the sample surface. And a plurality of semiconductor light sources disposed around the semiconductor light source, and a plurality of reflecting members that reflect illumination light emitted from the plurality of semiconductor light sources, and the illumination light having passed through the reflecting member at least once Are irradiated obliquely from below the sample surface.

  In addition, it is preferable that the said reflection member is rotatably provided and the inclination of the reflective surface with respect to the said sample surface is changeable.

  The optical axes of the plurality of semiconductor light sources are preferably perpendicular to the sample surface.

  In the dark field illumination, the angle formed by the reflecting surface of the reflecting member and the sample surface is θ, the spread angle of the plurality of semiconductor light sources is α, and the numerical aperture of the objective lens provided in the microscope is When NA is satisfied, it is preferable to satisfy the condition of the following formula θ> (NA + α) / 2.

  Further, during the oblique illumination, the angle formed between the reflecting surface of the reflecting member and the sample surface is θ, the spread angle of the plurality of semiconductor light sources is α, and the numerical aperture of the objective lens provided in the microscope is When NA is satisfied, it is preferable to satisfy the condition of the following formula θ <(NA + α) / 2.

  Moreover, it is preferable that the said reflection member is movable to an up-down direction according to the inclination of the said reflective surface.

  In addition, an angle formed between the reflection surface of the reflection member and the sample surface is θ, a spread angle of the semiconductor light source is α, and from the intersection of the optical axis of the semiconductor light source and the reflection surface of the reflection member to the sample surface Is the distance from the intersection of the optical axis of the semiconductor light source and the reflecting surface of the reflecting member to the semiconductor light source, and d is the distance from the optical axis of the semiconductor light source to the optical axis of the objective lens. When L, the following equation (d + d'cos2θ) tan (2θ-α) -d'sin2θ <L <(d + d'cos2θ) tan (2θ + α) -d'sin2θ must be satisfied Is preferred.

  Moreover, it is preferable that the said reflection member is a cylindrical mirror.

  In addition, the microscope according to the present invention preferably includes any one of the above illumination devices.

  According to the present invention, it is possible to provide an illuminating device having sufficient brightness and a wide illumination field and capable of at least one of dark field illumination and oblique illumination, and a microscope including the same, while reducing the size of the device. it can.

1 is a schematic configuration diagram of a microscope according to a first embodiment. It is the figure which looked at the illuminating device which concerns on 1st Embodiment from the optical axis direction of the objective lens. It is a block schematic diagram of the microscope concerning a 2nd embodiment. It is the figure which looked at the illuminating device which concerns on 2nd Embodiment from the optical axis direction of the objective lens. It is a block diagram of the illuminating device which concerns on 2nd Embodiment, Fig.5 (a) is the time of dark field observation at the time of using a high NA objective lens, FIG.5 (b) used the low NA objective lens. This is shown for each dark field observation. It is a block diagram of the illuminating device which concerns on 2nd Embodiment, FIG. 6 (a) shows at the time of performing dark field illumination, FIG.6 (b) shows each at the time of performing oblique illumination. It is a figure for demonstrating the effect of conditional expression (1), (2). It is a figure for demonstrating the effect of conditional expression (3). It is a block schematic diagram of the microscope concerning a 3rd embodiment.

Embodiments according to the present invention will be described below with reference to the drawings.
(First embodiment)
As shown in FIG. 1, the microscope MS1 according to the present embodiment includes a dark field illumination device 10, a bright field illumination device 20, a stage glass 31, an objective lens 32, an imaging lens 33, and an eyepiece lens 34. Have

  The dark field illumination device 10 includes a light source 11 and a mirror 12.

  The light source 11 includes a plurality of LEDs and is held by a base member 35 attached to the lower surface of the stage glass 31 on which the sample 30 is placed. The light source 11 is arranged in a hollow heptagon shape with the observation optical axis X perpendicular to the sample surface (that is, the mounting surface of the sample 30 on the stage glass 31) 31a as a center with respect to the base member 35. (See FIG. 2). In addition, each optical axis of LED which comprises the light source 11 is comprised so that it may become perpendicular | vertical with respect to the sample surface 31a.

  The mirror 12 is composed of seven plane mirrors 12a to 12g. The mirror 12 is provided below the light source 11 so as to draw a hollow heptagon around the observation optical axis X, and illuminates the sample surface 31a from obliquely below. The illumination light emitted from the light source 11 is reflected.

  FIG. 2 is a view of the dark field illumination device 10 as seen from the optical axis direction of the objective lens 32. As shown in FIG. 2, each of the light source 11 and the mirror 12 has a plurality of LEDs and a mirror 12a so as to draw a hollow polygon centered on the sample 30 placed on the observation optical axis X passing through the stage glass 31. ~ 12g is arranged. In the present embodiment, the light source 11 and the mirror 12 are both arranged in a heptagon shape, but if the number of corners is further increased, the directionality of illumination can be reduced. Conversely, if the number of corners is reduced, the configuration can be made simpler and the manufacturing cost can be reduced.

  In the dark field illumination device 10 having such a configuration, the illumination light emitted from the light source 11 in the direction opposite to the sample surface 31a (vertically below in the present embodiment) is reflected by the mirror 12 and is directly incident on the objective lens 32. The sample surface 31a is illuminated obliquely from below. Thereby, dark field illumination is achieved.

  Further, part of the illumination light irradiated on the sample 30 is diffracted or scattered by the sample 30, and only the light enters the objective lens 32, and an image 36 is formed by the imaging lens 33. The observer 37 observes the image 36 (here, a dark field image) through the eyepiece lens 34. As described above, the dark field observation of the sample 30 can be performed by the microscope MS1.

  The bright field illumination device 20 includes a light source 21, a collector lens 22, a relay lens 23, a mirror 24, and a condenser lens 25, and the illumination light emitted from the light source 21 is converted into a parallel light beam by the collector lens 22. After that, the light is converged by the relay lens 23, reflected by the mirror 24, condensed on a surface conjugate with the pupil of the objective lens 32, and converted into a parallel light beam by the condenser lens 25, so as to illuminate the sample 30. Yes. The light illuminating the sample 30 is imaged by the imaging lens 33 via the objective lens 32. The observer 37 observes the image 36 (here, a bright field image) through the eyepiece lens 34. Thus, the bright field observation of the sample 30 becomes possible by the microscope MS1. However, the bright field illumination device 20 is a representative example, and is not limited to this configuration as long as bright field illumination is possible.

  In the microscope MS1 having the above configuration, the observer can perform both dark field observation and bright field observation by switching between the light source 11 for dark field illumination and the light source 21 for bright field illumination as necessary. is there.

  As described above, in this embodiment, the light source 11 is installed so as to emit a light beam in a direction opposite to the sample surface 31a (in a direction away from the sample surface 31a), and the light beam 11 is reflected by the mirror 12 to be sample 30. It consists of the construction of lighting up. Accordingly, the optical path length between the light source 11 and the sample surface 31a can be extended while reducing the thickness of the dark field illumination device 10, and the luminous flux emitted from the light source 11 with a limited divergence angle is sufficiently widened to be wide. It becomes possible to secure Teruno.

  Note that the present embodiment is not limited to the above, and can be appropriately improved as long as it does not depart from the gist of the present invention. For example, in the dark field illumination device 10 according to the present embodiment, the angle of the mirror 12 is set so that the illumination light does not directly enter the objective lens 32. However, the angle of the mirror 12 is adjusted so that the illumination light is directly objective. By being configured to enter the lens 31, it can be used as a declination illumination device. This makes it possible to observe a transparent phase sample that cannot be seen in normal bright field observation.

(Second Embodiment)
A microscope MS2 according to the second embodiment will be described with reference to FIGS. In addition, in this embodiment, about the thing which has the same structure and function as said 1st Embodiment, description is abbreviate | omitted suitably using the same code | symbol.

  As shown in FIG. 3, the microscope MS2 according to the present embodiment includes a dark field illumination device 210, a bright field illumination device 20, a stage glass 31 on which a sample 30 is placed, an objective lens 32, and an imaging lens 33. And an eyepiece lens 34.

  In the second embodiment, the mirror 212 constituting the dark field illumination device 210 is rotatably provided, and the tilt of the reflecting surface with respect to the sample surface 31a can be changed, and the upper and lower sides according to the tilt of the reflecting surface. The point which can move to a direction differs from 1st Embodiment.

  That is, in the dark field illumination device 210 of the present embodiment, the mirror 212 includes seven plane mirrors 212a to 212g arranged in a heptagon shape with the observation optical axis X as the center, as shown in FIG. Each is provided rotatably. Further, the mirror 212 can be moved in the vertical direction according to the inclination of the reflection surface, and the distance between the light source 11 and the mirror 212 can be adjusted.

  FIGS. 5A and 5B show dark field illumination when performing dark field observation using a high NA objective lens (hereinafter, objective lens 32H) and a low NA objective lens (hereinafter, objective lens 32L), respectively. 2 is a configuration diagram of a device 210. FIG. As shown in FIG. 5A, when the high NA objective lens 32H is used in the dark field illumination device 210, the illumination angle is increased by raising the angle of the mirror 212, and the direct illumination light enters the objective lens 32H. Prevents incidence. At the same time, the mirror 212 is moved up and down (according to the tilt of the mirror 212), and the light source 11 and the mirror 212 are moved relative to each other (so as to be relatively shorter than when the low NA objective lens 32L is used). By adjusting the interval, the entire field of view can be illuminated uniformly. Conversely, as shown in FIG. 5B, when using the low NA objective lens 32L in the dark field illumination device 210, the angle of the mirror 212 is lowered to reduce the illumination angle. It is possible to reduce reflection and illuminate the sample 30 brightly. At the same time, the mirror 212 is moved up and down (according to the tilt of the mirror 212), and the light source 11 and the mirror 212 are moved to be relatively longer than when the high NA objective lens 32H is used. By adjusting the interval, the entire field of view can be illuminated uniformly.

  6A and 6B are configuration diagrams of the dark field illumination device 210 when performing dark field illumination and oblique illumination, respectively. As shown in FIG. 6A, when performing dark field illumination in the dark field illumination device 210, the angle of the mirror 212 is increased to increase the illumination angle so that the illumination light does not directly enter the objective lens 32. Configure. At the same time, the mirror 212 is moved up and down (according to the inclination of the mirror 212), and the distance between the light source 11 and the mirror 212 is adjusted (so as to be relatively shorter than that in the case of the oblique illumination described below). Thus, it becomes possible to illuminate the entire field of view without unevenness. Conversely, as shown in FIG. 6B, when performing oblique illumination in the dark field illumination device 210, the illumination angle is reduced by laying down the angle of the mirror 212, and the direct illumination light is directed to the objective lens 32. Configure to be incident. At the same time, the mirror 212 is moved up and down (in accordance with the tilt of the mirror 212), and the distance between the light source 11 and the mirror 212 is adjusted (so that it is relatively longer than in the dark field illumination). Thus, the entire field of view can be illuminated brightly.

  In the present embodiment, the angle formed by the reflecting surface of the mirror 212 and the sample surface 31a is θ, the spread angle of the light source 11 is α, and the numerical aperture of the objective lens 32 provided in the microscope MS2 is NA. It is preferable that conditional expression (1) is satisfied during dark field illumination and conditional expression (2) is satisfied during oblique illumination.

θ> (NA + α) / 2 (1)
θ <(NA + α) / 2 (2)

  The effect | action of said Formula (1) and (2) is demonstrated using FIG. The light source 11 constituting the dark field illumination device 210 emits a light beam (illumination light) having an angle α spread vertically downward with respect to the sample surface 31a. Then, the luminous flux is reflected by the reflecting surface of the mirror 212 that forms an angle θ with the sample surface 31a, and illuminates the sample surface 31a. At this time, the angle of the light beam (illumination light) having the smallest angle with the optical axis X of the objective lens 32 is (2θ−α). When performing dark field illumination, it is necessary that the angle of the light beam is larger than the NA of the objective lens 32, that is, conditional expression (4) must be satisfied.

  2θ−α> NA (4)

  Conditional expression (4) is equivalent to conditional expression (1). Conversely, when performing oblique illumination, it is necessary that the angle (2θ−α) of this light beam is smaller than the NA of the objective lens 32, that is, conditional expression (5) must be satisfied.

  2θ−α <NA (5)

  Conditional expression (5) is equivalent to conditional expression (2).

  In this embodiment, the angle formed between the reflection surface of the mirror 212 and the sample surface 31 a is θ, the spread angle of the light source 11 is α, and the sample is recorded from the intersection of the optical axis of the light source 11 and the reflection surface of the mirror 212. The distance to the surface 31a is d, the distance from the intersection of the optical axis of the light source 11 and the reflecting surface of the mirror 212 to the light source 11 is d ', and the distance from the optical axis of the light source 11 to the optical axis of the objective lens 32 is L. It is preferable that the condition of the following formula (3) is satisfied.

(d + d'cos2θ) tan (2θ-α) −d'sin2θ <L
<(d + d'cos2θ) tan (2θ + α) −d'sin2θ (3)

  The operation of the conditional expression (3) will be described with reference to FIG. The light source 11 emits a light beam (illumination light) having an angle α that extends vertically downward from the sample surface 31a. Then, the luminous flux is reflected by the reflecting surface of the mirror 212 that forms an angle θ with the sample surface 31a, and illuminates the sample surface 31a. At this time, in order to uniformly illuminate the sample surface 31a without passing through the sample surface 31a, the distance L between the optical axis of the light source 11 and the optical axis of the objective lens 32 is set to a light beam emitted from the light source 11 with a spread angle α. When the distances from the intersection points a and b with the sample surface 31a to the optical axis of the light source 11 are La and Lb (La <Lb), it is necessary to satisfy the following expression (6).

  La <L <Lb (6)

The above La and Lb are each expressed by the following formula from geometric calculation.
La = (d + d′ cos2θ) tan (2θ−α) −d′sin2θ (7)
Lb = (d + d′ cos2θ) tan (2θ + α) −d′sin2θ (8)

  When the expressions (7) and (8) are substituted into the conditional expression (6), the conditional expression (3) is derived.

  As described above, in the second embodiment, by changing the angle of the reflecting surface of the mirror 212 and adjusting the irradiation angle of the illumination light, it is possible to obtain optimum brightness and flare according to the numerical aperture of the objective lens 32. Dark-field illumination with less is possible. Further, in the dark field illumination device 210, if the illumination angle of the illumination light is adjusted by tilting the mirror 212 so that the illumination light is directly incident on the objective lens 32, the dark field illumination can be easily switched to the oblique illumination. Is possible. In addition, if the mirror 212 is moved in the vertical direction in conjunction with the change in the tilt of the mirror 212 and the distance between the light source 11 and the mirror 212 is adjusted, the illuminance unevenness of the entire visual field can be reduced.

  Furthermore, since the sample 30 is illuminated with divergent light in the present embodiment, a wider area can be illuminated. Therefore, even when observing with the low-magnification objective lens 32, it is possible to illuminate the periphery of the visual field without unevenness.

(Third embodiment)
A microscope MS3 according to the third embodiment will be described with reference to FIG. In addition, in this embodiment, about the thing which has the same structure and function as said 1st Embodiment, description is abbreviate | omitted suitably using the same code | symbol.

  As shown in FIG. 9, the microscope MS3 according to the present embodiment includes a dark field illumination device 310, a bright field illumination device 20, a stage glass 31 on which a sample 30 is placed, an objective lens 32, and an imaging lens 33. And an eyepiece lens 34.

  In the third embodiment, the mirror 312 constituting the dark field illumination device 310 is a cylindrical mirror (so-called concave mirror), and the sample surface 31a is provided so as to be rotatable (similar to the second embodiment). The first embodiment is different from the first embodiment in that the inclination of the reflection surface with respect to can be changed, and the reflection surface can also be moved in the vertical direction in conjunction with this.

  According to the third embodiment having such a configuration, the divergent light (illumination light) emitted from the light source 11 is reflected by the cylindrical mirror 312 and becomes a light beam that is approximately parallel or converged within the tangential plane, thereby causing the sample 30 to pass through. Illuminate. At this time, since the irradiation angle of the illumination light to the sample surface 31a is limited, it is possible to prevent the direct light from entering the objective lens 32. Therefore, even when the objective lens 32 having a relatively large numerical aperture is used, flare is small and good dark field observation is possible.

  Further, according to the present embodiment, the light source 11 and the mirror 312 are changed by changing the tilt angle of the mirror 312 according to the numerical aperture of the objective lens 32 and moving the mirror 312 in the vertical direction in conjunction with this. It is possible to adjust the distance between and dark field illumination brightly and with little flare.

  The present invention as described above is not limited to the above-described embodiment, and can be appropriately improved as long as it does not depart from the gist of the present invention.

MS1 to MS3 Microscope 10, 210, 310 Dark field illumination device (illumination device)
11 Light source (semiconductor light source)
12, 212, 312 Mirror (reflective member)
20 Bright field illumination device 30 Sample 31 Stage glass 31a Sample surface 32 Objective lens 33 Imaging lens 34 Eyepiece

Claims (9)

A microscope illumination device capable of at least one of dark field illumination and oblique illumination,
A plurality of semiconductor light sources arranged around the observation optical axis perpendicular to the sample surface below the sample surface,
A plurality of reflecting members that reflect illumination light emitted from the plurality of semiconductor light sources,
An illumination apparatus, wherein the illumination light that has passed through the reflection member at least once is irradiated from an obliquely lower side of the sample surface.   The illumination device according to claim 1, wherein the reflection member is rotatably provided, and an inclination of the reflection surface with respect to the sample surface can be changed.   3. The illumination device according to claim 1, wherein optical axes of the plurality of semiconductor light sources are each perpendicular to the sample surface. During the dark field illumination,
When the angle formed by the reflecting surface of the reflecting member and the sample surface is θ, the spread angle of the plurality of semiconductor light sources is α, and the numerical aperture of the objective lens provided in the microscope is NA, the following equation θ > (NA + α) / 2
The lighting device according to claim 3, wherein the following condition is satisfied. During the oblique illumination,
When the angle formed by the reflecting surface of the reflecting member and the sample surface is θ, the spread angle of the plurality of semiconductor light sources is α, and the numerical aperture of the objective lens provided in the microscope is NA, the following equation θ <(NA + α) / 2
The lighting device according to claim 3, wherein the following condition is satisfied.   The lighting device according to claim 2, wherein the reflecting member is movable in the vertical direction according to the inclination of the reflecting surface. The angle between the reflecting surface of the reflecting member and the sample surface is θ, the spread angle of the semiconductor light source is α, and the distance from the intersection of the optical axis of the semiconductor light source and the reflecting surface of the reflecting member to the sample surface Is d, the distance from the intersection of the optical axis of the semiconductor light source and the reflecting surface of the reflecting member to the semiconductor light source is d ′, and the distance from the optical axis of the semiconductor light source to the optical axis of the objective lens is L. When
(d + d'cos2θ) tan (2θ-α) -d'sin2θ <L <(d + d'cos2θ) tan (2θ + α) -d'sin2θ
The lighting device according to claim 3, wherein the following condition is satisfied.   The lighting device according to claim 1, wherein the reflecting member is a cylindrical mirror. A microscope comprising the illumination device according to any one of claims 1 to 8.

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