JP3766869B2 - Micro force measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a micro force measuring apparatus that measures, over time, a mechanical force acting between micro particles such as protein molecules and a predetermined base substance.
[0002]
[Prior art]
Conventionally, for example, a minute glass probe for measuring the magnitude of a minute force generated when a motor protein molecule as a minute particle interacts with a protein filament as a base substance with an accuracy of pN (piconeuton) A method using optical tweezers has been known. These use a small glass probe tip or optical tweezers as a small spring balance to fix a single motor protein molecule on the particles captured by the micro glass probe tip or optical tweezers. When the protein filament is fixed on the surface and the two are brought close to each other, when the interaction works between them, the displacement of the particles captured by the tip of a small glass probe or optical tweezers based on the movement of the motor protein is observed, By measuring this displacement, it is possible to measure the change over time in the strength of the force acting between the motor protein molecule and the protein filament (see, for example, Patent Document 1 and Non-Patent Document 1). ).
[0003]
Also, by using the laser radiation pressure, feedback control of the position of the probe in the direction perpendicular to the surface of the object to be observed allows the direction perpendicular to the surface of the object to be observed while maintaining a constant distance from the surface of the object to be observed. An intermolecular force microscope that performs non-contact measurement of the attractive force and repulsive force is known (see, for example, Patent Document 2).
[0004]
However, these methods do not consider means for measuring the force in the horizontal direction by eliminating the displacement caused by thermal fluctuations and external forces of the probe and particles, and therefore, the relative positions between the minute particles are not counted. The problem remains that the horizontal force cannot be detected while controlling in nanometer order.
[0005]
Therefore, the present applicant fixed minute particles as a device that made it possible to control the relative position of minute particles such as motor proteins and protein filaments and the base material in the horizontal direction on the order of several nanometers. A probe position control mechanism that performs feedback control so that the probe whose position changes with the movement of the minute particles is stationaryly fixed to a predetermined target position using the radiation pressure of the laser for light pressure, and the light We have developed a pressure measuring laser comprising measuring means for measuring and recording the laser radiation output over time. The probe is a probe that fixes fine particles, a light irradiation unit that is connected to the probe and irradiated to the laser for light pressure, and a cantilever that functions as a support unit that supports the light irradiation unit. The cantilever is coated with a metal such as gold in order to improve the reflectance of the laser for light pressure. (See Patent Document 3)
[0006]
[Patent Document 1]
JP 9-43434 A
[Patent Document 2]
Japanese Patent Laid-Open No. 7-12825
[Patent Document 3]
Japanese Patent Application No. 2001-308744
[Non-Patent Document 1]
TREND in Biotechnology vol.19 no.6 June 2001 P211-P216
[0007]
[Problems to be solved by the invention]
However, if the probe is a cantilever using a metal such as the above micro force measuring device, heat is generated and deformed by the irradiation of the laser for light pressure at the time of measurement, and the amount of movement of the probe caused by light is changed. It left the problem that it could have an impact that could not be ignored.
[0008]
Therefore, in order to solve such a problem, a micro force measuring device including a probe that is stable with respect to the radiation pressure of the laser for optical pressure and can give an accurate measurement value is provided.
[0009]
[Means for Solving the Problems]
That is, the present invention is for measuring a mechanical force acting between a minute particle and a predetermined base substance, and includes a probe that fixes the minute particle, and the movement of the minute particle. A probe position control mechanism that feedback-controls the probe whose position changes with the stationary pressure to a predetermined target position by using the radiation pressure of the light pressure laser, and measures and records the radiation output of the light pressure laser over time. In the micro-measuring device having the measuring means, at least the region irradiated to the laser for light pressure of the probe is made of a non-metallic dielectric material, that is, a material having no free electrons. It is a micro force measuring device. Note that examples of the nonmetallic dielectric include glass, quartz glass, quartz, silicon, and diamond.
[0010]
If this is the case, even if the irradiation area is irradiated with light from a laser for light pressure, heat generation due to free electron vibration does not occur, so that the probe can be measured accurately with high accuracy without deformation or deterioration of the probe. The value can be obtained. It is also possible to increase the number of times the probe can be used and the time to prevent an increase in cost due to replacement of parts.
[0011]
Further, as a preferred specific embodiment of the probe, a probe for fixing fine particles, a light irradiation unit connected to the probe and irradiated with the laser for light pressure, and a support unit for supporting the light irradiation unit, The thing which comprises and is mentioned.
[0012]
As a light irradiation part, what was comprised with plate glass and what was comprised with the prism are mentioned.
[0013]
As a specific aspect of the support portion, a base material may be fixed to the observation object surface and configured to be movable in the horizontal direction with respect to the observation object surface. In such a case, the light irradiation part and the support part are formed so as to be an integrated plate-like body, and the integrated light irradiation part and the support part are installed in a direction perpendicular to the observation target surface. In this way, the manufacturing can be simplified. Further, in order to correspond to the movement of the minute particles fixed to the probe in a direction perpendicular to the observation target surface, the support portion is configured to be movable in the vertical direction with respect to the observation target surface. What should I do?
[0014]
In order to simplify and simplify the apparatus, the laser radiation pressure may be applied by irradiating the optical pressure laser from the objective lens.
[0015]
Further, as a specific configuration of the probe position control mechanism, a position detecting light irradiating means for irradiating light to the probe, a projecting means for projecting an interference image by the light irradiation on a split photodiode, and a probe based on the interference image And a detecting means for detecting and measuring the position of the probe as a probe position detecting means, and further comprising an adjusting means for adjusting the intensity of the light pressure laser irradiated to the probe from the detection result of the detecting means.
[0016]
Regarding the suppression of probe fluctuation due to heat, in the probe position control mechanism, the fluctuation of the probe is converted to a mean square displacement and is monitored and controlled to be held at 0.6 nanometers or less. It is possible to prevent the probe from fluctuating.
[0017]
In addition, a probe with a constant spring constant is connected to the fixture to enable measurement regardless of whether fine particles move in the forward or reverse direction relative to the irradiation direction of the laser for light pressure. It is desirable to load the probe with a radiation pressure of an arbitrary intensity and add an offset function so that dynamic equilibrium can be maintained.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0019]
This minute force measuring device fixes minute particles such as proteins to the probe 1 and measures the mechanical force acting between the minute particles and the base substance fixed to the observation object surface 2a. As shown in FIG. 1 and FIG. 2, the probe 1 and the probe 1 whose position changes with the movement of the minute particles are arranged as shown in FIG. It has a function as a probe position control mechanism A that performs feedback control so as to be stationary and fixed at a predetermined target position using the radiation pressure, and a measuring means B that measures and records the radiation output of the optical pressure laser over time. Further, the apparatus of the present embodiment further includes a total reflection fluorescence observation mechanism C for observing the single molecule of the minute particles.
[0020]
More specifically, as shown in FIGS. 3 to 6, the probe 1 first irradiates light that is a probe 1 a that fixes minute particles, and a region that is connected to the probe and is irradiated with the light pressure laser. And a thin plate-shaped cantilever 1d that functions as a support portion 1c that supports the light irradiation portion 1b.
[0021]
In this embodiment, the probe 1a employs a ZnO whisker, and fine particles such as protein are fixed to the tip of the probe 1a. As a fixing method, gold is attached to the probe 1a and a part of a protein, which is a fine particle, is modified with an SH group, and nickel is attached to the probe 1a and a His tag is fused to the protein. And a method of binding by the interaction of avidin and biotin.
[0022]
Further, the cantilever 1d is formed to have a length of 200 μm, a width of 20 μm, and a thickness of 100 nm, for example. The free end side to which the probe 1a is attached is used as the light irradiation unit 1b, and the base end is attached to an arbitrary fixing device (not shown). The side also serves as the support portion 1c. The spring constant is set to be about 0.1 pN / nm so that the spring constant can be moved in the horizontal direction with respect to the observation target surface 2a, and as shown in FIGS. 5 and 6, the observation target surface 2a. Is attached to the fixing device in a cantilevered manner. Note that the observation target surface 2a is a place where minute particles fixed to the probe 1a move, and a slide glass 2 is usually used. And in this embodiment, this cantilever 1d which functions as the light irradiation part 1b and the support part 1c is comprised with the plate-shaped glass which is a nonmetallic dielectric material.
[0023]
The probe position control mechanism A includes an irradiation unit A1 for irradiating the probe 1 with a laser for light pressure, a position detection irradiation unit A2 for irradiating the probe 1 with light for position detection, and the position detection for the split photodiode. A projecting means A3 for projecting an interference image by light irradiation of the irradiating means A2, a detecting means A4 for detecting and measuring the position of the probe 1 from the interference image, and a light pressure laser for irradiating the probe 1 from the detection result by the detecting means A4. And adjusting means A5 for adjusting the strength of the lens.
[0024]
The irradiation means A1 adjusts the irradiation intensity of the light beam from the light pressure laser light source 3 by an EMO (electro-optic modulator) 4, passes the light pressure laser lens 5, and reflects it by the light pressure laser reflecting mirror 6. The first objective lens 7 corresponding to the objective lens according to claim 8 is incident, condensed, and irradiated to the probe 1. Although not shown in the illustrated example, the laser beam output from the EMO 4 may be reflected by a plurality of condensing lenses or reflecting mirrors and incident on the first objective lens 7. In the present embodiment, a YAG (Yittrium Aluminum Garnet) laser (1064 nm, 500 mW) having a wavelength in the infrared region in which almost no absorption is observed in the glass is employed as the light pressure laser. Moreover, it sets so that it may irradiate to the diagonal direction with respect to the surface of the light irradiation part 1b which makes | forms plate shape, and the incident angle is about 80 degrees in this embodiment. As shown in FIG. 7, in P-polarized light and S-polarized light, the angle at which the greatest force can be obtained is selected from the relationship between the incident angle and the force applied to the glass cantilever 1d. In addition, as shown in FIG. 8, it has confirmed that the position of the probe 1 changes reliably and shows a reproducible result by the presence or absence of this optical pressure laser. Furthermore, as shown in FIG. 9, it has also been confirmed that there is a proportional relationship between the intensity of the laser for light pressure and the force applied to the probe 1. In addition, as shown in FIG. 10, the micro force measuring device of the present embodiment provides an offset function in which a light pressure of an arbitrary intensity is loaded on the probe 1 to bring the probe into a predetermined target position by dynamic equilibrium. As a force required for the offset, the radiation pressure of the laser for optical pressure is set to be sufficiently larger than the force of the fine particles fixed to the probe 1. For example, when measuring the movement of a protein as fine particles, a force larger than the force of this movement may be used, and therefore, it should be set in the range of more than 8 pN, preferably 25 pN.
[0025]
The position detection light irradiating means A2 spreads the light beam of the position detection laser light source 8 by the beam expander 9, and then reflects it by the position detection laser reflecting mirror 10, and as shown in FIG. The lens 7 is configured to be incident, condensed, focused (crossed) on the probe 1 and irradiated. The position detection laser needs to be configured so as not to have a special effect on the probe 1. In the present embodiment, a YAG laser (532 nm, 100 μW) is employed.
[0026]
The projection means A3 causes the position detection laser beam that has passed through the light irradiation unit 1b to enter the second objective lens 12 and is reflected by the second position detection laser reflecting mirror 11 so as to be within the two-division photodiode 13 that is a divided photodiode. Thus, a probe interference image is obtained.
[0027]
The detection means A4 converts the interference image into an electric signal as a position signal by a position detection amplifier 16 having an IV converter 14 and a differential amplifier 15 connected to the two-divided photodiode 13, and further converts A- The digital signal is converted by the D converter 17 and the output signal is integrated and recorded in the data recording computer 18 for monitoring.
[0028]
The adjusting means A5 is configured to convert the position signal into a feedback signal by the feedback circuit 19 and transmit the signal to the EMO 4 to adjust the intensity of the optical pressure laser, thereby fixing the probe 1 stationary. At this time, as shown in FIG. 3, the radiation pressure of the laser for optical pressure is applied in the opposite direction to the force applied by the fine particles by feedback control, and the probe 1 is made to stand still on the appearance. Here, the movement of minute particles fixed to the probe 1 and the fluctuation due to heat as the background are generated in the probe 1. By inputting the position signal to the feedback circuit 19 and following the target value signal, the fluctuation of the probe 1 is reduced. It is set so that it is suppressed to 0.6 nanometer or less in terms of root mean square displacement. The interference fringes change when the position of the probe 1 is displaced, but it is known that the amount of change changes with a certain correlation with the position change of the probe 1. Position measurement is possible.
[0029]
The measuring means B measures the radiation output with time by the computer 18 connected to the laser light source 3 for light pressure or the EMO 4 or a dedicated control device (not shown), and indirectly measures the mechanical load on the probe 1. It is something that can be done.
[0030]
The total reflection fluorescence observation mechanism C irradiates a laser beam having a wavelength for exciting a specific fluorescent substance (dye) labeled on a minute particle at an incident angle set so as to totally reflect the observation target surface 2a. The fluorescent material excited in an evanescent field in the range of about 100 nm from the observation object surface 2a is observed. Specifically, in the example shown in the figure, a blue laser (473 nm, 500 μW) is used as the excitation light, and the light beam of the excitation laser light source 20 is passed through the beam expander 21 and the condensing lens 22 to be excited light. The object surface 2a is reflected from the lower laser reflecting mirror 23 and irradiated through the first objective lens 7 from below, and the irradiated region is imaged by, for example, the CCD 24 and displayed as an image on a monitor (not shown).
[0031]
As shown in FIG. 11, the force acting between the motor protein (kinesin) 25, which is a minute particle, and the filament protein (microtubule) 26, which is a base substance, is measured by the minute force measuring apparatus configured as described above. The operation of the case will be described.
[0032]
First, the motor protein 25 is labeled with a predetermined fluorescent substance (dye), and the motor protein 25 is fixed to the probe 1a. At this time, by irradiating the observation target surface 2a with an excitation light laser and observing an image of the fluorescence state of the excitation light captured by the CCD camera 24 with a monitor, one molecule of the motor protein 25 is present on the probe 1a. You can check if it is fixed. The motor protein 25 is brought close to the filament protein 26 fixed to the observation object surface 2a on the slide glass 2.
[0033]
The light pressure laser light source 3 irradiates the surface of the light irradiation part 1b of the cantilever 1d with a light pressure laser beam 3 through the first objective lens 7 at an incident angle of 80 ° and a diameter of about 20 μm. At this time, when the light pressure laser is irradiated to the light irradiation part 1b made of glass (indicated by F1 in the figure), as shown in FIGS. 3 and 4, the ratio is dependent on the incident angle. A portion is reflected (indicated by F2 in the figure), a part is refracted (indicated by F3 in the figure), and is transmitted and emitted (indicated by F4 in the figure).
[0034]
On the other hand, the laser beam output from the position detection laser light source 8 is spread by the beam expander 9, reflected by the first position detection laser reflecting mirror 10, incident on the first objective lens 7, and condensed. The position of 1 is detected. The position detection laser that has passed through the probe 1 enters the second objective lens 12 and is reflected by the second position detection laser reflecting mirror 11. Then, a probe interference image is obtained in the two-divided photodiode 13 reflecting the position of the probe 1. Here, the probe 1 is randomly displaced due to thermal fluctuation, but this is detected as the movement of the interference image (FIGS. 12 and 13). The interference image is converted into an electric signal as a position signal by the position detection amplifier 16, digitized by the A / D converter 17, and input to the computer 18. The computer 18 converts the background due to thermal fluctuation or the like into a mean square displacement and calculates. The position signal enters the feedback circuit 19 and is converted into a feedback signal. This feedback signal shifts to EMO4, and the irradiation intensity of the light pressure laser light source 3 is adjusted according to the feedback signal.
[0035]
Then, regardless of the generation of force by the motor protein 25 fixed to the probe 1a by the radiation pressure of the light pressure laser adjusted by the feedback signal, the probe 1 is apparently fixed stationary. At this time, the displacement of the probe due to the thermal fluctuation when the feedback shown in FIG. 12 is not applied can be controlled and fixed with an accuracy of about 0.6 nanometer by feedback control as shown in FIG. Can be controlled in the same way as In the present embodiment, since an offset function is added, as shown in FIG. 10, when the motor protein 25 fixed to the probe 1 moves in a direction opposite to the light pressure laser irradiation direction, radiation is performed. The strength applied to the pressure corresponds to the force obtained by adding the force applied to the offset and the force associated with the movement of the motor protein 25. On the other hand, when the motor protein 25 moves in the same direction as the light pressure laser irradiation direction, the radiation pressure of the light pressure laser corresponds to a force obtained by subtracting the force accompanying the movement of the motor protein 25 from the force acting on the offset. It will be.
[0036]
Then, the force acting between the motor protein 25 and the filament protein 25 is obtained by using the spring constant of the cantilever 1d to determine the relationship between the feedback signal and the radiation pressure of the optical pressure laser with respect to the probe 1 and analyzing the feedback signal. Can be obtained.
[0037]
The micro force measuring device according to the present embodiment described above has a cantilever 1d having a function as the light irradiation unit 1b of the light pressure laser made of glass, so that it can be compared with a conventional cantilever coated with metal. Thus, deformation based on heat generation can be prevented and accurate data can be obtained. As a result, the probe 1 can be used for a long time, and cost reduction can be expected. Moreover, since glass is used as a non-metallic dielectric, it is easy to obtain and easy to process.
[0038]
In the present embodiment, as described above, the light pressure laser is adjusted in intensity by the EMO 4 and reaches the probe 1 via the light pressure laser lens 5, the light pressure laser reflector 6, and the first objective lens 7. I am doing so. The position detection laser causes the light beam from the position detection laser light source 8 to reach the probe 1 via the beam expander 9, the position detection laser reflector 10, and the first objective lens 7. Further, the excitation laser also causes the light beam of the excitation laser light source 20 to reach the observation object surface 2 a via the beam expander 21, the condenser lens 22, the excitation laser reflector 23, and the first objective lens 7. I have to. In other words, since such an optical system that can be handled relatively easily and flexibly is employed, a plurality of light sources having different wavelengths can be easily connected. In addition, since all of the laser for pressure, the laser for position adjustment, and the laser for excitation are set so as to pass through the first objective lens 7, the configuration of the apparatus can be simplified and it can be prevented from becoming bulky.
[0039]
In addition, since the offset function is added to the probe 1, measurement can be performed even if minute particles fixed to the probe 1 move in any direction left or right with respect to the observation target surface 2a.
[0040]
Further, in the micro force measuring apparatus of the present embodiment, the irradiation means A1 for irradiating the probe 1 with the laser for light pressure is configured to include the 500 mW YAG laser and the EMO4. It has also been clarified through experiments that can be performed at 0.6 nm rms. That is, since control can be performed with very high accuracy, the force of minute particles can be measured more accurately.
[0041]
Further, as an effect peculiar to the present embodiment, since the total reflection fluorescence observation mechanism C is incorporated, it is confirmed by observing whether only one molecule of the motor protein (kinesin) 25, which is a fine particle, can be fixed to the probe 1a. And more accurate sliding force measurement can be realized. Further, the filament protein (microtubule) as a base material is also labeled with a fluorescent substance, and a laser that irradiates excitation light having a wavelength different from the wavelength irradiated to the motor protein 25 is mounted, and the motor protein 25 and the filament protein 26 are mounted. You may be able to observe both.
[0042]
The present invention is not limited to the above embodiment.
[0043]
For example, only the region irradiated with the probe may be configured by glass, or the entire probe including the probe may be configured by glass.
[0044]
Moreover, as a material which comprises a light irradiation part, if it is a nonmetallic dielectric material, it will not be restricted to glass, For example, things like quartz glass, quartz, silicon, diamond may be used.
[0045]
Further, the probe may be such that the light irradiation part and the support part are formed separately.
[0046]
Further, as shown in FIG. 14, a probe 100 including a probe 100a, a light irradiation unit 100b constituted by a prism, and a columnar or prismatic support 100c separate from the light irradiation unit 100b. It may be such that it has. The diameter of the support part 100c is set smaller than that of the light irradiation part 100b, and the support part 100c is movable in the horizontal direction with respect to the observation object surface 2a and is movable in the vertical direction. In addition, the same code | symbol is attached | subjected and shown to the structure similar to the said embodiment.
[0047]
Even with such a probe 100, it is possible to suppress the generation of heat due to irradiation of the laser for light pressure and to give an accurate measurement value. In addition, as shown in the figure, the incident light is indicated by F1 and the reflected light is indicated by F2, and if it is a prism, the light pressure laser can be totally reflected, so that the irradiation intensity of the light pressure laser necessary for measurement can be suppressed. Is possible. In addition, in the case of such a probe 100, when a force in a direction perpendicular to the observation object surface 2a when the fine particles move is generated, the force is absorbed by the movement of the support portion 100c. Therefore, measurement can be performed without crushing minute particles fixed to the probe 1a.
[0048]
The fine particles are not limited to proteins, and may be other fine particles such as DNA and RNA, cells, and the like.
[0049]
In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
[0050]
【The invention's effect】
The present invention is implemented in the form as described above, and has the following effects.
[0051]
That is, according to the micro force measuring device of the present invention, even when the irradiation region of the probe is irradiated with light from the laser for light pressure, heat generation due to free electron vibration does not occur, thereby preventing deformation and deterioration of the probe. It is possible to obtain appropriate measurement values with high accuracy. It is also possible to increase the number of times the probe can be used and the time to prevent an increase in cost due to the replacement of parts.
[Brief description of the drawings]
FIG. 1 is a device configuration diagram showing an embodiment of the present invention.
FIG. 2 is a functional configuration diagram showing the embodiment.
FIG. 3 is an explanatory diagram showing a state in which the probe is irradiated with a light pressure laser in the embodiment.
FIG. 4 is an explanatory view showing a state in which the probe for light pressure in the embodiment is irradiated to the probe through the surface of the observation object.
FIG. 5 is a partial perspective view showing a state of a probe and an observation object surface in the same embodiment.
FIG. 6 is an explanatory diagram illustrating a state in which the probe is irradiated with a position detection laser in the embodiment.
FIG. 7 is a graph showing the relationship between the incident angle of the optical pressure laser to the probe and the force acting on the probe in the same embodiment;
FIG. 8 is a graph showing a result of changing the position of the probe due to the radiation of the light pressure laser when the intensity of the light pressure laser is changed in the embodiment.
FIG. 9 is a graph showing the relationship between the light pressure laser intensity and the radiation pressure applied to the probe in the same embodiment;
FIG. 10 is an explanatory diagram showing an offset function in the embodiment.
FIG. 11 is a diagram showing a case where a force acting between a motor protein and a filament protein is measured in the same embodiment.
FIG. 12 is a graph showing a change with time of displacement due to thermal fluctuation of the probe when feedback control is not performed in the embodiment.
FIG. 13 is a graph showing a change with time of displacement due to thermal fluctuation of the probe when feedback control is applied in the embodiment.
FIG. 14 is a perspective view showing the main part of another embodiment of the present invention.
[Explanation of symbols]
1 ... Probe
1a ... Probe
1b: Light irradiation part
1c ... support part
2a: Object surface to be observed
7 ... Objective lens (first objective lens)
13: Split photodiode (dual photodiode)
25 ... fine particles (motor protein)
26 ... Base material (filament protein)
100: Probe
100a ... tip
100b ... Light irradiation part
100c ... support part
A: Probe position control mechanism
A2 ... Irradiation means for position detection
A3 ... Projection means
A4 ... Detection means
A5 ... Adjustment means
B ... Measurement means

Claims (12)

It is for measuring the mechanical force acting between a minute particle and a given base material,
A probe fixing the fine particles;
A probe position control mechanism that performs feedback control so that the probe whose position changes with the movement of the minute particles is stationary and fixed to a predetermined target position using a radiation pressure of a laser for light pressure;
In a micro-measuring device having measuring means for measuring and recording the radiation output of the laser for light pressure over time,
A region irradiated with at least the light pressure laser of the probe is formed of a non-metallic dielectric ,
A part of the laser for light pressure transmits a region irradiated to the laser for light pressure of the probe . 2. The micro force measuring apparatus according to claim 1, wherein the light pressure laser is a YAG laser. The probe includes a probe for fixing the minute particles, a light irradiation unit that is connected to the probe and is irradiated with the light pressure laser, and a support unit that supports the light irradiation unit. The micro force measuring device according to claim 1 or 2 . The micro force measuring apparatus according to claim 3 , wherein the light irradiating unit is made of sheet glass. The micro force measuring apparatus according to claim 3 , wherein the light irradiating unit is constituted by a prism. The micro force measuring device according to claim 3, wherein the base material is fixed to an observation object surface, and the support portion is configured to be movable in a horizontal direction with respect to the observation object surface. 7. The micro force measurement according to claim 6, wherein the light irradiation part and the support part are formed into an integral plate shape, and the integral light irradiation part and the support part are installed in a direction perpendicular to the observation object surface. apparatus. The micro force measuring apparatus according to claim 6 , wherein the support portion is further configured to be movable in a direction perpendicular to an observation object surface. Minute force measuring device according to which any one of claims 1 to 8 so as to provide a laser radiation pressure by irradiating a laser for the light pressure from the objective lens. The probe position control mechanism is
A position detecting light irradiating means for irradiating the probe with light;
A projecting means for projecting the interference image by the light irradiation onto the split photodiode;
Detection means for detecting and measuring the position of the probe from the interference image;
Minute force measuring device according to any one of claims 1 to 9 or and a means for adjusting the intensity of the photon pressure laser irradiating from the probe detection result by the detecting means. The probe position control mechanism monitors and controls that the fluctuation of the probe is converted to a mean square displacement and is held at 0.6 nanometers or less, so that the fluctuation of the probe due to thermal fluctuation or the displacement of the probe due to external force can be reduced. minute force measuring device according to any configuration to that of claims 1 to 10 to prevent. An offset function is added so that a probe having a constant spring constant is connected to a fixture, and a radiation pressure of an arbitrary intensity is applied to the probe by an optical pressure laser so that dynamic equilibrium can be maintained. 11. The micro force measuring apparatus according to any one of 11 above.

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