JP2007183111A - Light intensity detection device, optical device provided with same, and microscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light intensity detection device for reducing the affection of flare of the acousto-optical element (AOTF). <P>SOLUTION: The light intensity detection device 3 comprises: an acousto-optical element 32 which is arranged on the light path emitted from light sources L1, L2 and L3; a light splitting optical element 18 for splitting a part of the light, arranged on the path of the light emitted from the acousto-optical element 32; an optical detector 20 for detecting the intensity of split light; and a polarizer 19 arranged on the light path between the acousto-optical element 32 and the light detector 20. The optical device is composed of a light source device 1 provided with the light intensity detection device 3, and a laser microscope 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light intensity detection device in an optical device.

Conventionally, light from a laser light source is selected by a acousto-optic device (hereinafter referred to as AOTF in this specification) at a specific wavelength, and at the same time, the intensity of the laser light is adjusted and separated by a separation mirror disposed in the optical path. It is known that the light intensity of a laser beam is separated and the light intensity of the laser light is detected by a photometric intensity detector (see, for example, Patent Document 1).
JP 2003-90704 A

  However, in the light intensity detection of the configuration disclosed in Patent Document 1, a part of the laser light that has passed through the AOTF is scattered by the AOTF and spreads concentrically around the laser light (hereinafter referred to as flare). This flare is substantially constant regardless of the voltage applied to the AOTF. As a result, there is a problem that even if the voltage applied to the AOTF is zero, the output value of the light intensity detector does not become zero due to flare and it is difficult to detect the accurate light intensity of the laser beam.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a light intensity detection device that is not affected by the flare of AOTF, a light source device having the light intensity detection device, and a microscope.

  In order to solve the above problems, the present invention provides an acoustooptic device disposed in an optical path of light emitted from a light source, and an optical path of light emitted from the acoustooptic device. A branching optical element for branching a part, a photodetector for detecting the intensity of the branched light, and a polarizer disposed in an optical path between the acoustooptic element and the photodetector. A light intensity detecting device is provided.

  The present invention also provides a microscope having the light intensity detection device.

  Moreover, this invention provides the light source device which has the said light intensity detection apparatus.

  The present invention also provides a microscope having the light source device.

  ADVANTAGE OF THE INVENTION According to this invention, the light intensity detection apparatus which is not influenced by the flare of AOTF, and a light source device and microscope which have this can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 shows a light source device having a light intensity detector device according to the present invention and a laser microscope using laser light from the light source device as illumination light.

  In FIG. 1, reference numeral 1 denotes a light source device having a plurality of laser light sources L1, L2, and L3. Reference numeral 2 denotes a laser microscope for observing a specimen using laser light emitted from the light source device 1.

  The light source device 1 includes a plurality of laser light sources L1. L2 and L3. The laser light sources L1, L2, and L3 have different wavelengths of emitted laser light. Note that the number of laser light sources is not limited to three. Laser light emitted from the laser light source L1 passes through the dichroic mirror 17 and enters the AOTF 32. The laser light emitted from the laser light source L2 is reflected by the dichroic mirror 16 in the direction of the dichroic mirror 17, reflected by the dichroic mirror 17, and is incident on the AOTF 32 with the same optical axis as the laser light source L1. The laser light emitted from the laser light source L3 is reflected by the dichroic mirror 15 in the direction of the dichroic mirror 16, transmitted through the dichroic mirror 16, and reflected by the dichroic mirror 17, and has the same optical axis as the laser light source L1. Incident on the AOTF 32. In this way, the laser beams emitted from the laser light sources L1, L2, and L3 travel on the same optical axis. Shutters 13, 12, and 11 are disposed in the optical paths between the laser light sources L1, L2, and L3 and the dichroic mirrors 17, 16, and 15, respectively, and a laser light source that enters the AOTF 32 is selected by a control device (not shown). .

  The laser light incident on the AOTF 32 is incident on the branch optical element 18 after the light intensity of the laser light is adjusted by the AOTF 32 based on a signal from a control device (not shown). The branch optical element 18 has a characteristic of reflecting a part of the incident laser beam and transmitting the other part. A glass plate is used for the branch optical element 18, but a half mirror with adjusted reflection intensity may be used. The laser light reflected by the branching optical element 18 is incident on the polarizer 19 provided to remove the flare generated by the AOTF 32, passes through the polarizer 19 and enters the photodetector 20, and the light intensity of the laser light is detected. Is done. The polarization direction of the polarizer 19 is set in the same direction as the laser light emitted from the AOTF 32. The AOTF 32, the branch optical element 18, the polarizer 19, and the photodetector 20 constitute the light intensity detection device 3.

  The laser light transmitted through the branch optical element 18 enters the fiber coupling 21 through the shutter 14. The shutter 14 is controlled to be opened and closed by a control device (not shown). In this way, the light source device 1 is configured.

  The optical fiber 31 connected to the fiber coupling 21 of the light source device 1 is connected to the fiber coupling 41 of the illumination optical system of the laser microscope 2 and used as a light source of the laser microscope 20. The laser light emitted from the fiber coupling 41 is made substantially parallel light by the collimator lens 22, reflected by the dichroic mirror 25 toward the objective lens 23, enters the XY scanner 26, and is condensed on the sample 27 by the objective lens 23. The Since the laser light is two-dimensionally scanned by the XY scanner 26, as a result, the sample 27 can be scanned in the XY two-dimensional direction.

  The laser beam reflected by the specimen 27 is condensed by the objective lens 23, descanned by the XY scanner 26, transmitted through the dichroic mirror 25, and imaged on the pinhole 28 by the condenser lens 24. The light transmitted through the pinhole 28 is detected by a photodetector 29, processed by an image processing device (not shown), and then displayed and observed on a monitor (not shown). In this way, the laser microscope 2 is configured. The laser microscope 2 can also observe the fluorescence from the specimen 27 by replacing the dichroic mirror 25 with a filter set in which a dichroic mirror and a fluorescent filter are combined.

  The AOTF 32 of the light intensity detection device 3 can change the wavelength according to the frequency of a signal applied from a control device (not shown) and the amount of laser light passing through the voltage. Further, the laser beam incident on the AOTF 32 needs to be linearly polarized light.

  The laser light after passing through the AOTF 32 is linearly polarized light whose polarization direction is rotated by 90 degrees with respect to the incident laser light. The laser light that has passed through the AOTF 32 is divided into zero-order light and primary light, but it is the primary light that can adjust the amount of light and select the wavelength, and this primary light enters the branching optical element 18. And used as illumination light. The zero-order light is shielded by a light shielding plate (not shown) and is not incident on the branch optical element 18.

  The AOTF 32 utilizes crystal diffraction and generates concentric flares centered on the optical axis of primary light due to scattered light. This flare is non-polarized light and is generated in a constant amount regardless of the voltage applied to the AOTF 32, and the flare remains without disappearing even when a voltage that minimizes the laser light is applied. As a result, the flare is reflected by the branching optical element 18 and is incident on the photodetector 20 to be detected, making it difficult to accurately measure the light intensity of the laser light. In addition, since the diameter of the incident laser light in the fiber coupling 21 is small or the diameter of the optical fiber 31 is small and the diameter of the flare generated concentrically around the optical axis is large, the flare is the incident end face of the fiber coupling 21. Or, it does not enter the incident end face of the optical fiber 31.

  In the light intensity detection device 3 according to the present invention, a polarizer 19 is disposed between the branch optical element 18 and the photodetector 20. Since the polarization direction of the polarizer 19 is set to the same direction as the polarization direction of the laser beam reflected by the branch optical element 18, the laser beam can be transmitted and unpolarized flare can be shielded. As a result, it is possible to prevent the flare from entering the photodetector 20, and if the voltage applied to the AOTF 32 is minimized and the laser beam is made zero, the light intensity detected by the photodetector 20 becomes zero and the accuracy of the laser beam is increased. It is possible to detect a high light intensity. The polarizer 19 can be disposed between the AOTF 32 and the branch optical element 18, but at this time, the amount of laser light is reduced due to the insertion of the polarizer 19 into the optical path. It is necessary to consider. However, it is preferable that the laser light source has a sufficient amount of light because the flare of the laser light toward the fiber coupling 21 can be cut.

  Further, a shutter 14 is provided between the branch optical element 18 and the fiber coupling 21, and the voltage applied to the AOTF 32 can be adjusted by closing the shutter 14 when adjusting the amount of laser light. After adjustment, the shutter 14 is opened and laser light can be incident on the fiber coupling 21 and used as illumination light for the laser microscope 2 via the optical fiber 31. Further, by guiding the output of the light detector 20 to a control device (not shown) and controlling the voltage applied to the AOTF 32 so that the output value of the light detector 20 becomes constant, the fiber even if the output of the laser light source fluctuates. The intensity of the laser beam emitted in the direction of the coupling 21 can be kept constant, and can be used as a light source for long-time measurement such as time-lapse measurement.

  Further, the correlation between the light intensity of the laser beam branched by the branching optical element 18 (detection intensity of the light detector 20) and the light intensity irradiated to the sample 27 (light intensity measured by another light detector). Is measured in advance, it is possible to display the light intensity of the laser light irradiated on the specimen 27 in terms of the output value of the photodetector 20.

  As described above, according to the light intensity detection device 3 according to the present invention, since the flare generated in the AOTF 32 can be cut and only the laser light can be incident on the light detector 20, the light intensity of the accurate laser light can be reduced. Measurement becomes possible. In addition, by incorporating the light intensity detection device 3, it is possible to maintain a laser beam with an accurate light intensity for a long time using the signal of the light detector 20, and to configure the light source device 1 suitable for time lapse etc. It becomes possible. Further, by using the light source device 1 as a light source of the laser microscope 2, it becomes possible to irradiate the specimen with laser light having an accurate light intensity.

(Second Embodiment)
FIG. 2 is a schematic configuration diagram of a laser microscope and a light source device incorporating a light intensity detection device according to the present invention. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 2, the light source device 101 is the same as that of the first embodiment except for the light intensity detection device 3 in the first embodiment, and the description thereof is omitted.

The selected laser light from the light source device 101 is incident on the illumination optical system of the laser microscope 102 via the optical fiber 31 and the fiber coupling 41. The laser light emitted from the fiber coupling 41 is converted into substantially parallel light by the collimator lens 22 and is incident on the AOTF 32. The light intensity of the laser light is adjusted by the AOTF 32 and emitted toward the branch optical element 18, and a part of the light is reflected by the branch optical element 18, passes through the polarizer 19, and enters the photodetector 20. The laser light transmitted through the branching optical element 18 is incident on the dichroic mirror 25 and reflected in the direction of the objective lens 23, enters the objective lens 23 via the XY scanner 26, and is collected on the sample 27. Other configurations are the same as those in the first embodiment, and a description thereof will be omitted. The operation and effect of the light intensity detection device 3 are the same as those in the first embodiment.

  In the second embodiment, since the light intensity detection device 3 is built in the laser microscope 102, the light source device 101 can be used in various ways, and various wavelengths of the laser light source can be selected. Can do. Therefore, it is possible to obtain a microscope capable of measuring the light intensity of accurate laser light simply by attaching a general light source device to the laser microscope.

(Third embodiment)
FIG. 3 is a schematic configuration diagram of a laser microscope incorporating the light intensity detection device according to the present invention. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. In the third embodiment, the light source device is also built in the laser microscope, and the microscope and the light source device are integrated.

  In FIG. 3, the configuration from the laser light sources L1, L2, and L3 to the shutter 14 is the same as that of the light source device 1 of the first embodiment. The light intensity detection device 3 is disposed in the optical path between the dichroic mirror 17 and the shutter 14 and has the same action as in the first embodiment.

  The laser light emitted from the shutter 14 is focused on the pinhole 43 by the collimator lens 42 of the illumination optical system of the laser microscope 100. The laser beam condensed in the pinhole 43 is made into substantially parallel light by the condenser lens 22 and enters the dichroic mirror 25. Other configurations are the same as those of the first embodiment, and a description thereof will be omitted. In this way, the laser microscope 100 is configured. The operation and effect of the light intensity detection device 3 are the same as those in the first embodiment.

  In the third embodiment, a laser microscope system in which the light detection device 3 and the light source device are built in the laser microscope 100 can be configured. It is possible to control the intensity or the like of the laser light applied to the specimen via the control device of the laser microscope 100. Furthermore, laser light with stable light intensity can be supplied in long-time measurement such as time lapse. It can also be applied to a confocal microscope. Further, the present invention is particularly effective when the size of the light receiving surface of the photodetector is sufficiently larger than the spot diameter of incident light.

  The above-described embodiment is merely an example, and is not limited to the above-described configuration and shape, and can be appropriately modified and changed within the scope of the present invention.

1 is a schematic configuration diagram of a light source device and a laser microscope according to a first embodiment having a light intensity detection device according to the present invention. The schematic diagram of the laser microscope and the light source device of the second embodiment having the light intensity detection device according to the present invention is shown. FIG. 5 is a schematic configuration diagram of a laser microscope and a light source device according to a third embodiment having a light intensity detection device according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Light source device 2,100,102 Laser microscope 11, 12, 13, 14 Shutter 15, 16, 17, 25 Dichroic mirror 18 Branching optical element 19 Polarizer 20 Photo detector 21, 41 Fiber coupling 22 Collimator lens 24 , 42 Condensing lens 23 Objective lens 26 XY scanner 27 Specimen 28, 43 Pinhole 29 Optical detector 31 Optical fiber 32 Acoustooptic element (AOTF)
L1, L2, L3 Laser light source

Claims (6)

An acoustooptic device disposed in the optical path of the light emitted from the light source;
A branching optical element disposed in the optical path of the light emitted from the acoustooptic element and branching a part of the light;
A photodetector for detecting the intensity of the branched light;
A light intensity detection device comprising: a polarizer disposed in an optical path between the acoustooptic device and the photodetector.   The light intensity detection apparatus according to claim 1, wherein the polarizer is provided between the photodetector and the branch optical element.   The light intensity detection apparatus according to claim 1, wherein a polarization direction of the polarizer and a polarization direction of light emitted from the acousto-optic element coincide with each other.   A microscope having the light intensity detection device according to any one of claims 1 to 3.   A light source device comprising the light intensity detection device according to claim 1.   A microscope having the light source device according to claim 5.

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