JP3525151B2 - Friction photon two-dimensional distribution measurement method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dimensional distribution measuring technique of luminescence intensity, which is used for measuring a generation site of emitted photons, for example, regarding a luminescence phenomenon due to friction between material surfaces. is there.

[0002]

2. Description of the Related Art Conventionally, as a method for measuring the two-dimensional distribution of emitted light with the resolution of an optical microscope, a measuring device using a microscope, a multi-channel plate and a CCD camera has been developed. These conventional devices have focused on observation of heat generation and fluorescence, and an optical microscope and an image acquisition device having only the measurement performance of photons belonging to the visible to near infrared region have been used.

[0003]

However, in the conventional measuring device, since the transmission performance and the detection sensitivity to ultraviolet photons are not sufficient, the ultraviolet region generated in the process of deexcitation of the electron in the highly excited state in the atom / molecule There is a drawback in that it is impossible to observe a phenomenon that mainly emits photons, for example, a discharge phenomenon that occurs in the atmosphere.

In addition, although it is necessary to remotely observe the dynamic phenomenon as described above to a certain extent, in the conventional two-dimensional distribution measuring technique, the objective lens of the optical microscope and the measuring object are separated from each other. Since the distance, that is, the working distance was small and insufficient, it was difficult to cope with the measurement of such a phenomenon.

The present invention overcomes the drawback of the conventional method that the observation range is limited to photons in the visible to near-infrared region, and includes a phenomenon in which photons in the ultraviolet region are generated and a dynamic phenomenon such as friction. It is an object of the present invention to provide a technique capable of measuring a general light emitting phenomenon with a two-dimensional distribution at a long working distance and a resolution of an optical microscope.

[0006]

In order to solve the above-mentioned problems, the friction photon two-dimensional distribution measuring method of the present invention is
A friction contact is formed between two members by a friction forming device, and the photon from the friction contact is passed through a spectral filter to an image forming surface through a microscope objective lens having a transmission characteristic of ultraviolet photons located in the vicinity of the friction contact. the Rukoto be processed in the control device is focused, it is characterized by separating the occurrence location of a phenomenon occurring in the friction surface by measuring the two-dimensional distribution of luminous intensity of photons from the friction contact proximity.

Further, the friction photon two-dimensional distribution measuring device of the present invention comprises an objective lens having a transmission characteristic of ultraviolet photons, which is disposed between two friction members and is formed in the vicinity of a friction contact formed by a friction forming device. A lens barrel having the objective lens attached thereto and having a transmission characteristic of ultraviolet photons, a position adjusting device for adjusting the vicinity of the frictional contact of the subject and the position of the objective lens, and a photon reaching the image acquisition device from the objective lens. A microchannel plate inserted in the path, a switchable optical filter inserted in the path of the photons, the image acquisition device having a detection sensitivity for the photons arranged in the path of the photons, And a control device for controlling the operation of the image acquisition device.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings showing an embodiment. The present inventor has conducted earnest investigations and studies on optical microscopes and image acquisition devices ranging from general optical microscope parts to laser-related optical equipment parts, and as a result, has a high transmission characteristic for ultraviolet photons at a long working distance. By combining a microscope with an objective lens and an image acquisition device such as a high-sensitivity CCD camera that can measure the same photons, it is possible to measure, for example, the two-dimensional distribution of ultraviolet photons from atmospheric discharge occurring on a friction surface. Based on this finding, the present invention has been completed.

First, the two-dimensional distribution measuring device of the present invention will be described. In FIG. 1, reference numeral 1 is a friction photon two-dimensional distribution measuring device of the present invention. The friction photon two-dimensional distribution measuring device 1 is roughly divided into a measuring device 2 including an objective lens 3, a lens barrel 4, and an image acquisition device 5, and a friction forming device 6 for generating an atmospheric discharge phenomenon due to friction.

As the performance of the objective lens 3, it can be mentioned that it has a high transmission characteristic of ultraviolet photons and a long working distance. To solve this problem, based on a condensing optical system for laser processing, which has a long working distance. , It is possible to measure photons from UV to near-infrared by applying all the lenses made of high transmission material of UV photon as an objective lens.

The performance of the lens barrel 4 includes a high transmission characteristic of ultraviolet photons, which is also realized by using a lens made of a material having a high transmission characteristic of ultraviolet photons in the optical system. In addition, in order to measure a two-dimensional distribution limited to a certain wavelength band, for example, ultraviolet photons due to discharge and visible to near-infrared photons due to frictional heat, a design in which an optical filter 7 can be inserted in the middle of the lens barrel is used. To do. The optical filter 7 has several transmission wavelength bands and has a structure in which they are selectively used. The objective lens 3 is attached to the front end of the lens barrel 4, and the objective lens 3 of the objective lens 3 is located in the vicinity of a contact point 13 between a flat plate disk 8 and a contactor 12 which will be described later. The lenses 3 are arranged so as to face each other. The lens barrel 4 is provided with the revolver 14, and when a plurality of objective lenses are mounted, they can be quickly exchanged.

As the image acquisition device 5, a CCD camera having a built-in microchannel plate detector having a high detection sensitivity for ultraviolet to near infrared photons is applied to measure weak light emission such as friction photons. Will be realized.

A one-dimensional photodiode array can also be used as the image acquisition device 5. The image acquisition device 5 has a single or a plurality of microchannel plates (MCP) 9 incorporated therein to have a photosensitivity amplification function, and when the image acquisition device 5 is a CCD camera, C
It is possible to reduce the number of nozzles by providing a CD cooling function.

The position to be observed can be adjusted by the position adjustment fine movement stages 33 and 34. The position adjustment fine movement stage 35 can adjust the working distance L to focus the image. The measuring device 2 is a support 3
It is supported by 6.

The image acquisition device 5 is controlled by a controller 17 including an image acquisition device controller 15 and an image acquisition device control computer 16.

A friction forming device 6 for generating an atmospheric discharge phenomenon due to friction has a structure in which a pin-shaped contact 12 is pressed against a back surface 11 of a rotating flat plate disk 8 to form a contact point 13. The friction speed can be changed. The flat disk 8 is attached to a rotary shaft 21 by a disk retainer 18, the rotary shaft 21 is rotated by a motor 22, and the rotary shaft 21 is supported by a bearing 23 and rotatably supported by a frame 24.
The rotation unevenness of the flat disk 8 is corrected by the disk rotation unevenness correction screw 31. An arm 26 is pivotally supported by a lever bearing 27 on a column 25 of the frame 24, and a contact 12 is attached to one end of the arm 26. The contact 12 comes into contact with the flat plate disk 8 from the back surface 11 and contacts 13
To form. A load weight 28 is suspended from the other end of the arm 26.

Next, the friction photon two-dimensional distribution measuring method of the present invention is constructed as described above.
Is done as follows. That is, the flat disk 8 is attached to the rotary shaft 21 by the disk retainer 18,
The motor 22 is driven and rotated. In this state, the contact 12 whose contact pressure is adjusted by using the load weight 28 is brought into contact with the flat disk 8 from the back surface 11 to form friction at the contact 13. Triboluminescence is generated from the contact 13 and its vicinity. This triboluminescence includes photons in the visible to near infrared and ultraviolet regions.

The objective lens 3 whose working distance is adjusted by the position adjusting fine movement stage 35 is located near the contact point 13 and is located close to the surface 10 side of the flat disk 8, and these frictional light emission is collected by the objective lens 3. The light enters the lens barrel 4, is discriminated by switching the optical filter 7, and enters the image acquisition device 5.

In the image acquisition device 5, the frictional luminescence which has passed through the optical filter 7 is imaged on the image surface whose photosensitivity is amplified by the multi-channel plate 9 and converted into an electric signal. This image is processed by the image acquisition device control computer 16 to measure the two-dimensional distribution of frictional light emission such as frictional photons.

(Experimental Example 1) FIG. 2 was a combination of a two-dimensional photon distribution measuring device and a device for generating frictional luminescence, and an experiment was conducted to measure the location of discharge luminescence generated on a friction surface.

The objective lens used has a magnification of 20 times and the working distance is 15 mm. Observe the contacts from the side of the flat disk. Three types of optical filters that can be inserted into the lens barrel were prepared: one having a transmission wavelength band of 300 to 420 nm (hereinafter, UV filter), one having a transmission wavelength band of 440 nm or more (hereinafter, UV cut filter), and no filter.

As a CCD camera, wavelengths from 280 to 85
A high-sensitivity CCD camera with a built-in microchannel plate with an effective sensitivity of 0 nm was used. The size of the CCD pixel is 24 μm, the interval between the pixels is 1 nm, and the number of pixels is a square having 512 × 512 pixels in the vertical and horizontal directions. In this embodiment, the photosensitivity amplifying function by the microchannel plate and the CCD cooling function for reducing noise are used.
The exposure time for measurement was 6 seconds.

In this embodiment, the magnification of the objective lens and the CCD
The resolution of the image acquired from the size of the pixel of the camera, that is, 24 + 1 μm is 1.25 μm. As the disk, an alumina single crystal having a high transmission characteristic of ultraviolet photons, that is, sapphire was used. As the pin, a diamond whose tip was spherically processed was used. The friction speed was 25 cm / s or less, and the pressing load was 1 N or less. The device was operated in air and the measurements were performed in a dark room.

When the optical filter is not inserted, light emission is observed at the contact and its periphery. By inserting the UV filter or the UV cut filter, two-dimensional distribution measurement of friction photons for each wavelength band, that is, discharge is performed. Succeeded in measuring the distribution or heat generation distribution with micrometer resolution. FIG. 2 shows a method of measuring the distribution of photons generated at the friction boundary between two surfaces by combining a two-dimensional photon distribution measuring device and a device for generating frictional luminescence.

In the present invention, since the objective lens having a long working distance is adopted, it becomes possible to measure the observation from the side of such a contact with the resolution of the optical microscope.
Also in the embodiment shown in FIG. 2, the two-dimensional distribution measurement of the friction photons generated in the gap between the two surfaces was successful.

(Experimental Example 2) [Introduction] Up until now, it has been considered that chemical reactions (tribochemical reactions) such as deterioration of lubricant on the friction surface are caused by frictional heat. The temperature of the contact has been measured. However, on the other hand, when a solid is destroyed, deformed, peeled, or worn,
In other words, when mechanical energy is applied to a solid substance, phenomena such as ultraviolet radiation and light emission due to defect formation are caused by tribolum.
It is generally known as inescence and widely known, and it has been pointed out that it may contribute to chemical reactions, but since it is a complicated phenomenon, there are many unclear points even in the physical process of triboluminescence. We measured the spectrum of light generated by scratching various ceramics surfaces in the atmosphere with diamond, and clarified that the cause of this ultraviolet radiation is light emission from nonequilibrium plasma due to atmospheric discharge breakdown. The purpose of this research is to study the heat generation phenomenon (visible,
We aim to clarify the physical phenomenon of friction by separating the locations where near infrared rays) and electrical phenomena (ultraviolet rays) occur. By investigating high-energy (ultraviolet) radiation and triboelectric phenomena in detail, it is expected to elucidate the relationship with tribochemical reactions that are not explained by thermochemical reactions.

[Experimental Method] As shown in FIG. 3, the friction experiment was carried out by a typical pin-on-disk test method. p
The radius of curvature of the diamond (100) surface is 200μ for in
The spherical surface of m was used. In consideration of observing ultraviolet rays (300-400 nm), an Al ₂ O ₃ single crystal (0001) surface-polished (sapphire) disk having a high ultraviolet transmittance was used as a test material. A measurement system consisting of a high-sensitivity CCD camera with built-in optical amplifier = optical filter = microscope, which can measure from ultraviolet rays to near infrared rays, was installed on the back side of the disk to obtain a spectral image of the frictional contact surface. The test was performed in the air (28.8 ° C., 67%). 640 x 6
Images of 40 μm ² are acquired. Optical filter,
Spectral imaging is possible.

[Results and Discussion] FIG. 4 shows friction surface radiation (wavelength 3
50-850 nm) shows the measurement results of the two-dimensional intensity distribution.
The x-axis shows the sliding direction of the disc. Strong emission (A) is seen at the contact points. It also emits light around the contacts (A
', B and B') were observed. From the spectral distribution measurement,
It was revealed that the light emission at the contact point (A and A ') is the frictional heat radiation, and the light emission around the contact (B and B') is the light emission from the discharge plasma. Focusing on the discharge phenomenon, and because there is no dependence on the frictional velocity of the light emitting location, it is highly possible that the discharge occurs in the gap between the diamond and the disk. Assuming discharge in a gap, dielectric breakdown electrolytic strength of the atmosphere is 3 × 10 ⁶
The gap of several μm between the diamond and sapphire at the positions of V / m and B and B ′ suggested that the potential difference between the two surfaces was at least tens of V during rubbing. Figure 4 shows the diamond (100) surface and sapphire (000
1) Light reflection on the frictional contact surface and its periphery (3
50-850 nm) intensity distribution. The coordinates represent the number of pixels (one pixel corresponds to 1.25 μm). The horizontal axis represents the coordinates in the sliding direction, and the contact surface between the diamond and sapphire has a radius of 10 pixels centered at x = 272 and y = 257.
It is a circular shape of ls.

[0029]

As is clear from the above, according to the two-dimensional distribution measuring apparatus and method for friction photons of the present invention,
The photon measurement in the ultraviolet region is included in the function, and the two-dimensional distribution of light emission can be measured with the resolution of the optical microscope. Photons in the ultraviolet region are generated by deexcitation from a highly excited state of atoms, and for example, most of light emission in the atmospheric discharge phenomenon is in the ultraviolet region. Therefore, the effect can be exhibited in the study of the mechanism of discharge light emission caused by friction, which has not been observed in detail conventionally.

For example, in order to measure the location of weak light emission due to the electrostatic discharge phenomenon occurring in the vicinity of the frictional contact between material surfaces with the resolution of an optical microscope, it is necessary to use an optical system with the addition of ultraviolet photon transmission performance. It is necessary to combine a microscope and an image acquisition device that has high detection sensitivity for the photons.

Further, since it is necessary to observe the dynamic phenomenon as described above from a distance to some extent, the distance between the objective lens of the optical microscope and the object to be measured, that is, the working distance is made larger than before. It is necessary to take.

In measuring the two-dimensional distribution of friction photons,
When observing in and around the contact surface between a flat disk and a pin, a transparent flat disk with a high transmission characteristic of UV photons is used, and two-dimensional friction photons are observed by the method of observing from the surface opposite to the contact. Distribution measurement is realized.
Further, when observing the frictional contact point from the side, any material can be applied as the flat disk, and the measuring device of the present invention having a long working distance realizes the measurement.

[0033]

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a two-dimensional distribution measuring apparatus for friction photons and a method thereof according to the present invention, in which the generation location is measured by two-dimensional distribution measurement of photons generated in and around a friction surface. is there.

FIG. 2 is an explanatory diagram of an embodiment of the two-dimensional distribution measuring apparatus and method for friction photons according to the present invention, in which the generation location is measured by observing the side surface of the photon generated near the friction point.

FIG. 3 is a structural explanatory view of a light emission observation device for a Pin-disk friction surface.

FIG. 4 Diamond (100) surface and sapphire (00
The figure which shows the intensity | strength distribution of optical radiation in the frictional contact surface of 01) surface, and its periphery.

[Explanation of symbols]

1 Friction photon two-dimensional distribution measuring device 2 Measuring device 3 Objective lens 4 lens barrel 5 Image acquisition device 6 Friction forming device 7 Optical filter 8 flat disk 9 Multi-channel plate 10 surface 11 back side 12 contacts 13 contacts 14 Revolver 15 Image acquisition device controller 16 Image acquisition device control computer 17 Control device 18 disc restraint 21 rotation axis 22 motor 23 Bearing 24 frames 25 props 26 arms 27 Lever bearing 28 load weight 31 Disk rotation unevenness correction screw 32 Balance weight 33 Position adjustment fine movement stage 34 Position adjustment fine movement stage 35 Position adjustment fine movement stage 36 props

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References J. APPL. PHYS. , November 1, 2000, VOL. 88, NO. 9, p 5444-5447 (58) Fields investigated (Int.Cl. ⁷ , DB name) G01N 21/00-21/61 G01N 3/00-3/62 JOIS PATOLIS

Claims (7)

(57) [Claims] 1. A forms a frictional contact with the friction forming apparatus between the two members, the spectral photons from the friction contact through the microscope objective lens having a transmission characteristic of ultraviolet photons is positioned in the vicinity of the friction contact the Rukoto be processed in the control device is imaged on <br/> imaging surface through the filter, the occurrence of phenomena occurring in the friction surface by measuring the two-dimensional distribution of luminous intensity of photons from the friction contact near A method for measuring two-dimensional distribution of friction photons, which is characterized by separating points. 2. The friction contact is formed between the surface of the disk and the pin by rotating the disk and a pin in contact with the surface of the disk relative to each other. Method of two-dimensional distribution of friction photons in Japan. 3. An objective lens having transmission characteristics of ultraviolet photons, which is formed between two friction members by a friction forming device, and is disposed in the vicinity of a friction contact, and the objective lens is attached to the objective lens for ultraviolet photons. A lens barrel having a transmission characteristic, a position adjusting device for adjusting the position of the objective lens and the vicinity of the frictional contact of the subject, and a microchannel plate inserted in the path of the photons reaching the image acquisition device from the objective lens, A switchable optical filter inserted in the path of the photon, the image acquisition device having detection sensitivity for the photon arranged in the path of the photon, and control for controlling the operation of the image acquisition device An apparatus for measuring two-dimensional distribution of friction photons, comprising: 4. The friction photon two-dimensional distribution measuring device according to claim 3, wherein the image acquiring device is a CCD camera. 5. The friction photon two-dimensional distribution measuring apparatus according to claim 4, wherein the CCD camera has a CCD cooling function. 6. The friction photon two-dimensional distribution measuring device according to claim 4, wherein the micro channel plate is built in the CCD camera. 7. The two-dimensional friction photon distribution measuring apparatus according to claim 3, wherein the optical filter is capable of switching a plurality of different transmission wavelength bands.