JP2007285881A - Polarization microscope, magnetic field applying part for the polarization microscope and magnetic field application method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently apply a relatively large magnetic field to a measuring target, for a polarization microscope and based on this, to observe the dynamic magnetization response of the measuring target. <P>SOLUTION: The polarization microscope 10, capable of observing the magnetized state of the measuring target, is equipped with a stage 40 on which the measuring target is arranged; a pancake coil 32 having a flat shape and having a through-hole 32a provided at its center part; a flat plat-shaped coil holder 31, having a light transmission port formed to its central part and holding the pancake coil 32 to the part of the light-transmitting port and a plurality of adjusting screws 36, etc. for fixing the coil holder 31, in a state capable of positionally adjusting the same in the direction vertical, with respect to the surface of the stage between the stage 40 and an object lens 14. The light from the measuring target 50 passes through the control transmission port of the coil holder 31 and the through-hole 32a of the pancake coil 32, and is condensed by the object lens 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polarizing microscope, and a magnetic field applying component and a magnetic field applying method for a polarizing microscope for applying a magnetic field to a measurement object.

  For example, a polarization microscope is used to observe magnetic domains of a magnetic material used for a magneto-optical recording medium. According to the polarization microscope, it is possible to observe the magnetization state of the magnetic material by utilizing the property that the light reflected from the surface of the magnetic material rotates the polarization plane depending on the magnetization of the magnetic material.

  Further, in such a polarization microscope, one having a means for applying a magnetic field to an object to be measured from the outside has been proposed. For example, Patent Document 1 and Patent Document 2 disclose a polarizing microscope in which a permanent magnet or an electromagnetic coil is provided on the side of an objective lens or on the lower side of a stage so that a magnetic field is applied to an object to be measured. Yes.

As a conventional technique related to the present invention, Patent Document 3 discloses a technique in which a magnetic field generator is provided to magnetize the tip of a cantilever in a magnetic force microscope that observes the magnetic domain structure of a sample with a cantilever. Yes.
JP-A-62-288585 JP 58-199487 A JP-A-10-239409

  However, in the conventional polarizing microscope, there is no means for efficiently applying a relatively large magnetic field that changes a minute magnetic domain on the surface of the magnetic material to be measured. Even if you want to observe the response, it was difficult to realize it.

  For example, the method of applying an external magnetic field described in Patent Documents 1 and 2 generates a magnetic field that improves the transfer characteristics of the magnetic transfer plate or eliminates the labyrinth magnetic domain on the magnetic transfer plate. Or, when a magnetic bubble memory is used as an object to be measured, a magnetic field that generates a bias magnetic field is generated to the magnetic bubble memory, and a relatively large magnetic field is efficiently applied to a minute magnetic domain on the surface of the magnetic material. It was difficult to apply well.

  An object of the present invention is to provide a technique for enabling a predetermined magnetic field to be efficiently applied to a measurement object in a polarizing microscope and observing a dynamic magnetization response of the measurement object. It is another object of the present invention to provide a technique that enables fine adjustment of the strength and angle of a magnetic field applied to a measurement object.

  In order to achieve the above object, the present invention irradiates the object to be measured with light in the first polarization state and condenses the light from the object to be measured with the objective lens so as to have the second polarization state. In a polarization microscope capable of observing the state of magnetization of the object to be measured by extracting light and forming an image, a stage on which the object to be measured is disposed, and an electromagnetic coil having a flat shape and a through hole formed in the central portion A flat plate-shaped coil holder that has a transmission hole that can transmit light in the center and holds the electromagnetic coil at a portion of the transmission hole; and the coil holder between the stage and the objective lens with respect to the stage surface And fixing means for fixing in a vertically adjustable position, and light from the object to be measured passes through the transmission hole in the center of the coil holder and the through hole of the electromagnetic coil and is collected by the objective lens. It was set as the structure illuminated.

  According to such means, it is possible to efficiently apply a relatively large magnetic field to the object to be measured by disposing the electromagnetic coil between the objective lens having a small space and the stage. Further, by adjusting the distance between the stage and the coil holder, it is possible to adjust the strength of the magnetic field, the strength gradient, and the like.

  Specifically, a pancake coil may be applied as the electromagnetic coil. Further, the fixing means includes a plurality of screws that are fixed to the coil holder in a state of being rotatable with the tip projecting toward the stage, and by rotating the plurality of screws, the stage It is preferable to apply a configuration capable of adjusting the interval between the coil holders.

  With such a configuration, a larger magnetic field can be efficiently applied to the object to be measured. Further, by turning the screw, it is possible to finely adjust the position and angle of the coil holder, that is, to finely adjust the strength, strength gradient, direction, etc. of the magnetic field applied to the object to be measured.

  In addition, the magnetic field application component for a polarizing microscope of the present invention is a magnetic field application component for a polarizing microscope that is used by being fixed between an objective lens of a polarizing microscope and a stage, and has a flat shape with a through hole in the center. A pancake coil having a plate-shaped coil holder having a transmission port through which light can be transmitted in the center and holding the pancake coil in a portion of the transmission port; A plurality of screws fixed to the bottom surface side of the holder with their tips protruding, and applying a current to the pancake coil to apply a magnetic field to the object to be measured on the stage, and the plurality of screws Is configured to change the distance between the coil holder and the stage.

  Further, the magnetic field application method for a polarizing microscope of the present invention comprises holding a pancake coil having a flat shape and having a through hole in the center on a flat plate coil holder having a transmission port in the center, and the coil holder is attached to the stage and the covering. A magnetic field is applied to the object to be measured by passing a current through the pancake coil while being fixed between an objective lens that collects light from the object to be measured, and the light from the object to be measured is applied to the coil holder. The light is condensed on the objective lens through a transmission port and a through-hole of the pancake coil.

  By such means, a relatively large magnetic field can be efficiently applied to the object to be measured, and the strength and direction of the magnetic field can be adjusted.

  As described above, according to the present invention, since a relatively large magnetic field can be efficiently applied in the vicinity of the object to be measured, it is possible to observe, for example, the dynamic magnetic domain response of the magnetic material. There is an effect.

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

  FIG. 1 is a configuration diagram of a polarizing microscope according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view showing a fixing structure of a magnetic field application plate.

  The polarization microscope 10 of this embodiment irradiates the object to be measured with light of a predetermined polarization state, extracts the light of the predetermined polarization state from the reflected light and forms an image, thereby magnetizing the object to be measured. This state can be observed, and a relatively large magnetic field can be applied to the object to be measured during the observation.

  The polarizing microscope 10 includes a light source 11, a first polarizer 12 that linearly polarizes light from the light source, and a beam splitter 13 that divides an optical path of light directed to the object to be measured 50 and light reflected from the object to be measured 50. An objective lens 14 that is provided at the lower end of the lens barrel 14a and condenses the reflected light of the object to be measured 50; and a second polarizer 15 that extracts only light in a predetermined polarization state from the reflected light of the object to be measured 50; The digital camera 16 as imaging means that forms an image of the light passing through the second polarizer 15 and captures it as image data, the stage 20 on which the object to be measured 50 is set in the center, and the object to be measured (magnetic material) 50 The heater 21 for resetting the magnetization state by heating the magnetic field, the magnetic field application plate 30 as a magnetic field application component for applying a magnetic field to the object to be measured 50, and the driving of the light source 11, the digital camera 16, and the heater 21 And a control unit 40 for performing the energization control of the control and the magnetic field applying plate 30.

  The magnetic field application plate 30 has a flat electromagnetic coil 32 held at the center of a plate-like coil holder 31 having rigidity. The electromagnetic coil 32 is a pancake coil, and a hollow portion (through hole) 32a penetrating vertically is formed in the central portion. In addition, a through-hole is provided in the central portion of the coil holder 31, and the electromagnetic coil 32 is fitted and held in this through-hole portion. With such a configuration, a thin and relatively large magnetic field can be generated in the central portion, and further, the object 50 can be irradiated with light through the hollow portion 32a of the central portion or the reflected light of the object 50 can be reflected. Can be guided to the objective lens 14.

  The coil holder 31 has a rectangular plate shape, and four fine adjustment screws 36... Are arranged at four corners. The fine adjustment screws 36... Can be fixed to the stage 20 and finely adjusted with respect to the interval and angle with the stage 20. It is possible. The fine adjustment screws 36 are fixed in a state of protruding to the lower surface side of the coil holder 31 so as to extend in a direction perpendicular to the plate surface of the coil holder 31, and screw holes 20 b provided in corresponding positions of the stage 20. Are screwed together.

  FIG. 3 is a longitudinal sectional view showing in detail a fixing structure portion of the fine adjustment screws 36 of the coil holder 31. As shown in FIG. 3A, each fine adjustment screw 36 is inserted into a screw insertion hole 31b of the coil holder 31 so as to be idle, and a fixing ring is provided on the bottom surface side of the coil holder 31 of each fine adjustment screw 36. 36a (for example, E ring) is fixed, and the coil holder 31 is positioned in the height direction with respect to the fine adjustment screw 36. Therefore, the distance between the stage 20 and the magnetic field application plate 30 can be changed by turning the fine adjustment screw 36 and screwing the tip of the fine adjustment screw 36 into the screw hole 20 b of the stage 20. Further, the angle of the magnetic field application plate 30 can be finely adjusted by changing the screwing amounts of the left and right and front and rear fine adjustment screws 36.

  The fine adjustment screw 36 may be fixed as shown in FIG. That is, a screw hole 31c that is screwed with the fine adjustment screw 36 is provided on the coil holder 31 side, while a recess 20c that receives a tip portion of the fine adjustment screw 36 is provided on the stage 20. Even with such a configuration, the fine adjustment screw 36 can be rotated to change the interval between the stage 20 and the magnetic field application plate 30 or to adjust the angle of the magnetic field application plate 30.

  Next, processing for observing the dynamic magnetic domain response of the magnetic material using the polarizing microscope having the above-described configuration will be described.

  FIG. 4 shows an operation waveform diagram for explaining the observation process of the dynamic magnetic domain response of the magnetic material.

  First, as a pre-process of this observation process, after setting the measured object 50 on the stage 20, the height and angle of the magnetic field application plate 30 are adjusted. This adjustment is performed by turning the fine adjustment screw 36 while measuring the height and angle. By adjusting the height and angle of the magnetic field application plate 30, the strength gradient and angle of the magnetic field applied to the object to be measured 50 can be finely changed. Note that the strength of the magnetic field can also be adjusted by the magnitude of the current flowing through the electromagnetic coil 32.

  Next, the energization amount (the magnitude and pulse width of the pulse current) to the electromagnetic coil 32 and the observation timing (the time length from the magnetic field application timing to the photographing) are set for the control unit 40. Then, after such setting is completed, an instruction to start observation processing is given to the control unit 40 to execute processing.

  When the observation process is started, the control unit 40 first opens the shutter of the digital camera 16, drives the heater 21, energizes the electromagnetic coil 32, and the light source at the operation timing shown in FIG. 4. 11 flash irradiation is performed. Here, the driving of the heater 21 is for resetting the magnetization state of the magnetic body of the DUT 50. Then, in a state where the magnetization state of the magnetic material is reset, a magnetic field of a predetermined pulse is applied to the magnetic material by the output of the coil current of FIG. An image in a magnetized state is input to the image sensor of the digital camera 16.

  Further, since the exposure time is short in one flash irradiation, these operations are repeatedly executed a predetermined number of times (for example, 10 seconds) at a predetermined period (for example, 30 Hz period). Then, by integrating the output of the image sensor of the digital camera 16 during this period, it is possible to obtain one image obtained by imaging the state of the magnetic domain response after a predetermined time from the application of the magnetic field of the predetermined pulse.

  Further, by performing a plurality of such imaging processes by shifting the setting pattern of the output timing of the coil current back and forth as shown by the arrows in FIG. 4, imaging of the magnetic domain response after various times have passed since the magnetic field application. An image can be obtained. Further, by performing a plurality of imaging processes by changing the height and angle of the magnetic field application plate 30 and the current value and pulse width of the coil current, captured images of magnetic domain responses of various magnetic fields are obtained. I can do it.

  As described above, according to the polarizing microscope 10 of this embodiment, the magnetic field application plate 30 and the magnetic field application method, a relatively large magnetic field can be efficiently applied to the object 50 to be measured. The magnetic domain response can be observed.

  Further, since the height and angle of the magnetic field application plate 30 can be finely adjusted, the state of the applied magnetic field can be changed to various patterns, and dynamic magnetic domain responses in the respective patterns can be observed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the embodiment, the central portion of the coil holder is opened and the electromagnetic coil is held there. However, the central portion of the coil holder is configured by a transparent plate that transmits light, and the electromagnetic coil is mounted thereon. It may be placed and fixed.

  3A, without providing the fixing ring 36a, a spring is interposed between the coil holder 31 and the stage 20, and the coil holder 31 is urged toward the head side of the fine adjustment screw 36. By doing so, you may make it fix the coil holder 31 so that fine adjustment of height is possible.

  In addition, the configuration of the optical system of the polarization microscope described in the embodiment may be changed to various patterns, and the method for acquiring the observation image of the object to be measured can be changed to various patterns. For example, a film camera instead of a digital camera may be used as the imaging means, or an observation image may be acquired by opening and closing the shutter once by increasing the sensitivity of the camera. Alternatively, the object to be measured may be visually observed through an eyepiece while continuously applying a magnetic field by outputting current pulses to the electromagnetic coil 32. In the above-described embodiment, the reflection type polarization microscope that observes the reflected light from the object to be measured is illustrated. However, the present invention is similarly applied to the transmission type polarization microscope that observes the transmitted light from the object to be measured. I can do it.

It is a whole lineblock diagram showing the polarization microscope of an embodiment of the invention. It is the isolation | separation perspective view which showed the fixation structure of the magnetic field application plate. It is the longitudinal cross-sectional view which showed the fixation structure of the fine adjustment screw of a coil holder in detail, (a) is the 1st pattern, (b) is the 2nd pattern. It is an operation | movement waveform diagram which shows the operation | movement of the imaging process which images the state of the dynamic magnetic domain response of a to-be-measured object.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Polarizing microscope 11 Light source 12 1st polarizer 13 Beam splitter 14 Objective lens 14a Lens barrel 15 2nd polarizer 16 Digital camera 20 Stage 20b Screw hole 21 Heater 30 Magnetic field application plate (magnetic field application component)
31 Coil holder 31 Screw insertion hole 32 Electromagnetic coil (pancake coil)
32a Cavity part 36 Fine adjustment screw 36 Fixing ring 40 Control part 50 Measured object

Claims (6)

By irradiating the object to be measured with light in the first polarization state, condensing the light from the object to be measured with an objective lens and extracting the light in the second polarization state to form an image. In a polarizing microscope that can observe the state of magnetization of the measurement object,
A stage on which the object to be measured is placed;
A pancake coil with a flat shape and a through hole in the center,
A flat plate-shaped coil holder having a transmission port capable of transmitting light in the center and holding the pancake coil in a portion of the transmission port;
Fixing means for fixing the coil holder between the stage and the objective lens in a state in which the position can be adjusted in a direction perpendicular to the stage surface;
The light from the object to be measured is configured to be collected by the objective lens through the transmission hole in the center of the coil holder and the through-hole of the pancake coil,
further,
The fixing means has a plurality of screws that are fixed to the coil holder in a state where the tip can be rotated and a tip is projected to the stage side, and the stage and the coil are rotated by rotating the plurality of screws. A polarizing microscope characterized in that an interval between holders is adjustable. By irradiating the object to be measured with light in the first polarization state, condensing the light from the object to be measured with an objective lens and extracting the light in the second polarization state to form an image. In a polarizing microscope that can observe the state of magnetization of the measurement object,
A stage on which the object to be measured is placed;
An electromagnetic coil having a flat shape and a through-hole formed in the center;
A plate-shaped coil holder in which a transmission port capable of transmitting light is formed at the center, and the electromagnetic coil is held in a portion of the transmission port;
Fixing means for fixing the coil holder between the stage and the objective lens in a state in which the position can be adjusted in a direction perpendicular to the stage surface;
A polarizing microscope characterized in that light from the object to be measured passes through the transmission hole in the center of the coil holder and the through hole of the electromagnetic coil and is collected by the objective lens.   The polarizing microscope according to claim 2, wherein the electromagnetic coil is a pancake coil. The fixing means includes
A plurality of screws fixed to the coil holder in a rotatable state and in a state where tips are projected toward the stage;
The polarizing microscope according to claim 2 or 3, wherein a distance between the stage and the coil holder is adjustable by rotating the plurality of screws. A magnetic field application component for a polarizing microscope used by being fixed between an objective lens of a polarizing microscope and a stage,
A pancake coil having a flat shape and a through hole in the center;
A flat plate-shaped coil holder having a transmission port capable of transmitting light in the center and holding the pancake coil in the transmission port part;
A plurality of screws that are fixed to the coil holder in a rotatable state and with the tip protruding from the bottom side of the coil holder;
The magnetic field is applied to the object to be measured on the stage by passing an electric current through the pancake coil, and the interval between the coil holder and the stage is changed by rotating the plurality of screws. Magnetic field application component for polarizing microscope. A magnetic field application method for a polarization microscope that applies a magnetic field to an object to be measured fixed to a stage of a polarization microscope,
A flat-shaped coil holder having a flat shape and a through-hole in the center is held in a flat plate-shaped coil holder having a transmission port in the center,
The coil holder is fixed between the stage and an objective lens that collects light from the object to be measured, and a magnetic field is applied to the object to be measured by passing a current through the pancake coil.
A magnetic field application method for a polarizing microscope, wherein light from the object to be measured is condensed on the objective lens through a transmission port of the coil holder and a through-hole of the pancake coil.

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