JP2007309710A - Microperiodic groove observation method and observation device thereof, microperiodic groove machining observation method and machining observation device thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microperiodic groove observation method and a device and a machining observation method and a device, capable of accurately measuring and machining-measuring a groove gap between microperiodic grooves. <P>SOLUTION: When the groove gap in microperiodic groove M1 is observed with a surface machined by a femtosecond laser machining apparatus, the microperiodic groove observation method observes, in terms of vision or data, the wavelength λ of a measurement laser incident on the micro periodic groove M1 in the vertical surface direction or an arbitrary oblique direction; a diffraction angle β of the diffracted light L2 of the measurement laser, a measurement order m of a light receiver 20 catching the diffracted light at the diffraction angle; and the groove gap d by arranging the light receiver 20 at the measurement order m, obtained by a theoretical expression d(sinα±sinβ)=mλ related to the groove gap d of the microperiodic groove M1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an observation method and apparatus for fine periodic grooves (continuous periodic grooves having nano-periodic structure, discontinuous dimple processing grooves) surface-processed by, for example, a femtosecond laser processing machine, a processing observation method, and the processing thereof The present invention relates to an observation apparatus, and in particular, relates to an observation apparatus capable of observing and processing a groove interval of fine periodic grooves with high accuracy.

  In recent years, reduction of air pollution has been raised as the most important issue of global warming prevention measures. In particular, it is known that the main cause of air pollution is exhaust gas emitted from automobiles, and automakers are competing to develop low-emission vehicles in an international agreement. The destination is expected to spread worldwide through the development and commercialization of hybrid vehicles, electric vehicles, fuel cell vehicles, and the like. Under such circumstances, measures to improve automobile fuel efficiency and engine performance / durability include friction reduction between pistons and cylinders in the engine, reduction in bearing rotation friction, reduction in gear meshing friction, etc. It is desired to reduce the frictional resistance to the limit. For the processing method to reduce the frictional resistance of the sliding part (friction surface) or rotating part (rolling surface) of the engine to the limit, the surface of the surface is subjected to grooving of fine uneven stripes by the mechanical external force of the blade. A technique for forming fine periodic grooves (continuous periodic grooves with nano-periodic structures, discontinuous dimple processing grooves) with a femtosecond laser processing machine has been attracting attention and has been actively developed. In order to determine whether or not the fine periodic grooves are correctly generated, observation with a scanning electron microscope or a special observation device is required, but an innovative observation device is provided at present. It has not been. On the other hand, also in the semiconductor manufacturing field, a semiconductor surface that is surface-treated by a semiconductor manufacturing apparatus equipped with a femtosecond laser is generated and processed into a fine uneven state. There is also a need for an observation apparatus that measures such a fine uneven state.

  To observe the periodic interval (hereinafter referred to as the groove interval) of fine periodic grooves processed by the femtosecond laser processing machine with a scanning electron microscope, measurement is performed by recognizing the periodic interval of the subject. It has recognized. In addition, when an example of the semiconductor surface inspection apparatus is introduced, the surface of an object to be inspected such as a mounted circuit board is optically scanned, and a shape defect of a component is inspected based on the reflected light. The detailed configuration is such that a plurality of semiconductor laser elements 1, 2, and 3 are pulse-oscillated with a time difference, and lasers L1, L2, and L3 having their optical axes slightly shifted are incident on a polygon mirror 5 and optical scanning fθ. Optical scanning is performed at a predetermined pitch A on the surface 11 of the inspection object 10 through the lens system 6. While moving the inspection object 10 in a direction perpendicular to the optical scanning direction, the lasers L1r, L2r, and L3r reflected from the surface 11 of the inspection object are detected by the photodetectors 16a and 16b, and the photodetectors 16a and 16b are detected. The output electric signal is converted into a height signal by the arithmetic devices 17 and 18 (see, for example, Patent Document 1).

JP 2005-77158 A

  In order to observe the periodic interval of the fine periodic grooves with the scanning electron microscope, a very expensive scanning electron microscope must be installed as an inspection device, and pre-processing for recognizing the periodic interval of the subject is required. Since it is measured and recognized, it is not an optimal observation device at the production site even though it is good at the laboratory level. Further, in the semiconductor surface inspection apparatus, since the shape of the object to be inspected is limited to a flat circuit board, surface inspection of a concave peripheral surface such as an inner peripheral surface of a cylinder in an engine, the outer periphery of a piston It cannot be diverted to surface inspection. The reason for this is that, as in the present invention, the minimum groove width dimension (several hundreds of fine periodic grooves (continuous periodic grooves of nano-periodic structure, discontinuous dimple processing grooves)) processed by a femtosecond laser processing machine is used. This technique has a problem that it cannot be applied to (nm) observation.

  An object of the present invention is to solve the problems of the conventional scanning electron microscope and the like. The purpose of the new micro-periodicity is to enable high-precision observation and processing observation of the groove spacing of micro-periodic grooves (continuous periodic grooves with nano-periodic structure, discontinuous dimple processing grooves). The present invention provides a groove observation method, an observation apparatus, a machining observation method, and a machining observation apparatus. In addition, the major objective of the present invention is to promote the technological development of parts processing that contributes to the energy-saving effect and life-span-proof effect by reducing the energy loss by reducing the sliding friction resistance of various industrial machines. This will greatly contribute to measures to prevent global warming.

  According to a first aspect of the present invention, when observing a fine periodic groove whose surface has been processed by a femtosecond laser processing machine or the like, a direction perpendicular to the fine periodic groove or an arbitrary oblique direction is provided. The incident angle α and the wavelength λ of the measuring laser incident from the direction, the diffraction angle β of the diffracted light of the measuring laser, the measurement order m of the receiver that catches the diffracted light of the diffraction angle, and the fine A light receiving device is arranged at a measurement order m obtained from a theoretical formula d (sin α ± sin β) = mλ with a groove interval d of the periodic groove, and the groove interval d is measured and confirmed.

  According to a second aspect of the present invention, when observing a fine periodic groove whose surface is processed by a femtosecond laser beam machine or the like, the observation device of the fine periodic groove is perpendicular to the fine periodic groove or is arbitrarily inclined. A measurement order m of the diffraction angle β of the diffracted light of the measurement laser emitted from the measurement laser oscillator to the fine periodic groove while irradiating with the incident angle α in the direction and oscillating the measurement laser with a specific wavelength λ A laser receiver disposed on the monitor, a monitor device that displays received light information from the laser receiver, or an arithmetic processor that calculates the groove interval d of the fine periodic grooves by the theoretical formula d (sin α ± sin β) = mλ, It is characterized by comprising.

  The fine periodic groove observing method according to claim 3 of the present invention is the fine periodic groove observing method according to claim 1, wherein the measurement laser is a He-Ne laser, a GaN semiconductor laser, a femtosecond laser, or the like. The measurement order m of the photoreceiver corresponding to the diffraction angle β is characterized by a measurement order such as 0th order, 1st order, 2nd order, 3rd order or the like.

  The fine periodic groove observation device according to claim 4 of the present invention is the fine periodic groove observation device according to claim 2, wherein the measurement laser is a He-Ne laser, a GaN semiconductor laser, a femtosecond laser, or the like. The measurement order m of the photoreceiver corresponding to the diffraction angle β is characterized by a measurement order such as 0th order, 1st order, 2nd order, 3rd order or the like.

  According to a fifth aspect of the present invention, there is provided a method for observing the processing of a fine periodic groove, wherein the surface of a workpiece is irradiated with a femtosecond laser or the like from a vertical or arbitrary oblique direction to process the fine periodic groove, and at the same time, The incident angle α and its wavelength λ of the measurement laser incident on the fine periodic groove with a half mirror and incident on the fine periodic groove from a vertical plane direction or an arbitrary oblique direction, and the diffracted light of the measurement laser The measurement order m obtained from the theoretical formula d (sinα ± sinβ) = mλ of the diffraction angle β of the above, the measurement order m of the light receiver that catches the diffracted light of the diffraction angle, and the groove interval d of the fine periodic groove Further, a light receiver is arranged and the groove interval d is confirmed by actual measurement.

  A fine periodic groove processing observation apparatus according to claim 6 of the present invention is a laser oscillator that processes a fine periodic groove by irradiating a surface of a workpiece with a femtosecond laser or the like from a vertical or arbitrary oblique direction; A measurement laser that irradiates a measurement laser having a specific wavelength λ while being irradiated with an incident angle α in a vertical plane direction or an arbitrary oblique direction with respect to the fine periodic groove by being superimposed on the femtosecond laser by a half mirror. A laser oscillator, a fiberscope for light reception disposed at a measurement order m of a diffraction angle β of diffracted light reflected by the measurement periodic laser irradiated on the fine periodic groove, and information received from the fiberscope is monitored Is characterized by comprising an arithmetic processing unit for calculating the groove interval d of the fine periodic grooves by the theoretical formula d (sin α ± sin β) = mλ.

  According to a seventh aspect of the present invention, there is provided the fine periodic groove processing observation method according to the fifth aspect, wherein the measurement laser is a He-Ne laser, a GaN semiconductor laser, or a femtosecond laser. The measurement order m of the light receiver corresponding to the diffraction angle β is set to be a measurement order such as 0th order, 1st order, 2nd order, 3rd order or the like.

  The fine periodic groove processing observation apparatus according to an eighth aspect of the present invention is the fine periodic groove processing observation apparatus according to the sixth aspect, wherein the measurement laser is a He-Ne laser, a GaN semiconductor laser, or a femtosecond laser. The measurement order m of the light receiver corresponding to the diffraction angle β is set to be a measurement order such as 0th order, 1st order, 2nd order, 3rd order or the like.

  The observation method and apparatus for fine periodic grooves and the method and apparatus for processing and processing fine periodic grooves according to the present invention are composed of the above-described components and operate as follows. First, according to the method for observing the fine periodic groove, when observing the fine periodic groove formed on the surface of the workpiece by a femtosecond laser processing machine or the like, the fine periodic groove is perpendicular to the fine periodic groove. The wavelength λ of the measurement laser incident from the incident angle α in the surface direction or an arbitrary oblique direction, the diffraction angle β of the diffracted light of the measurement laser, and the measurement order of the receiver that catches the diffracted light of the diffraction angle By substituting the numerical data with m into the theoretical formula d (sin α ± sin β) = mλ, the groove interval d of the fine periodic groove is calculated. Whether the groove interval d is the same as the calculation of this theoretical formula can be easily confirmed by the output of the light receiver arranged at the measurement order m. That is, if the groove interval of the fine periodic groove is correctly generated, an output of diffracted light can be obtained from the light receiver. As a result, for example, as a measure for improving the fuel efficiency of automobiles, in the engine, the above-mentioned fine periodic grooves are machined on the inner peripheral surface of the cylinder and the outer peripheral surface of the piston ring to reduce the friction between the piston and the cylinder, and the rotation of the bearing The groove interval of the fine periodic grooves provided to reduce the frictional resistance such as friction reduction and gear meshing friction reduction to the utmost limit is accurately observed.

  Secondly, according to the observation device of the fine periodic groove, when observing the fine periodic groove formed on the surface of the workpiece by a femtosecond laser processing machine or the like, the wavelength λ The measurement laser is incident from the oscillator at an incident angle α in the vertical plane direction or in an arbitrary oblique direction. A laser receiver is arranged at the measurement order m of the diffraction angle β of the diffracted light of the measurement laser irradiated to the fine periodic groove from the measurement laser oscillator, and the received light information from the laser receiver is monitored equipment. Is visually confirmed. Further, the received light information from the laser receiver is calculated by processing the groove interval d of the fine periodic groove by the theoretical formula d (sin α ± sin β) = mλ stored in the processor, and the processing content is displayed. . Thereby, it is confirmed accurately whether or not the groove interval of the fine periodic groove is correctly generated. As a result, for example, as a measure for improving the fuel efficiency of automobiles, in the engine, the above-mentioned fine periodic grooves are machined on the inner peripheral surface of the cylinder and the outer peripheral surface of the piston ring to reduce the friction between the piston and the cylinder, and the rotation of the bearing The groove interval of the fine periodic grooves provided to reduce the frictional resistance such as friction reduction and gear meshing friction reduction to the utmost limit is accurately observed.

  Thirdly, according to the above-described fine periodic groove processing observation method and apparatus, first, the femtosecond laser is directed to the surface of the workpiece by a laser oscillator that oscillates the femtosecond laser. The fine periodic groove is processed by irradiating from. At the same time, a measurement laser with a wavelength λ is oscillated from the measurement laser oscillator and is superimposed on a half-mirror to the femtosecond laser and incident on the fine periodic groove at an incident angle α in the vertical plane direction or an arbitrary oblique direction. Is done. Then, the measurement laser is irradiated and reflected on the fine periodic groove, and the diffracted light is received by a light receiving fiberscope arranged at the measurement order m of the diffraction angle β. The received light information from the fiberscope is subjected to calculation processing of the groove interval d of the fine periodic groove by the theoretical formula d (sin α ± sin β) = mλ stored in the calculation processor, and the processing content is displayed. Accordingly, whether or not the groove interval of the fine periodic groove is correctly generated while processing the fine periodic groove by the femtosecond laser on the surface of the workpiece is accurately confirmed simultaneously. This enables feedback control of the output of the femtosecond laser so that it is generated with precise machining dimensions based on the monitoring information while monitoring the groove interval of the fine periodic groove, and the fine periodic groove as desired in advance. Can be processed and observed and inspected. Thus, for example, in order to improve the fuel efficiency of automobiles, in the engine, the above-mentioned fine periodic grooves are machined on the inner circumferential surface of the cylinder and the outer circumferential surface of the piston ring to reduce the friction between the piston and the cylinder, and the rotation of the bearing The fine periodic grooves provided to reduce frictional resistance such as friction reduction and gear meshing friction reduction to the utmost limit are generated with high precision.

  Fourth, in the observation method and apparatus for the fine periodic groove and the processing observation method and apparatus for the fine periodic groove, the measurement laser has a wavelength λ of 0.6328 μm and a visible He-Ne laser or GaN. Since a semiconductor laser or femtosecond laser is employed, the groove interval d of the fine periodic grooves on the workpiece surface determined by the wavelength of the processing femtosecond laser or the like (for example, within 0.8 μm to 1.6 μm) (Appropriate wavelength) can be observed optimally. That is, the groove interval d of the fine periodic groove (for example, 0.8 μm to 1.6 μm) cannot be accurately and clearly observed with an extremely short wavelength laser or a long wavelength laser. Sometimes. In addition, since He-Ne lasers and GaN semiconductor lasers are visible light, it is possible to observe the state of the irradiation of the fine periodic grooves on the workpiece surface and the state of diffracted light directly by the observer's vision. It is used selectively because of its good operability. Furthermore, the measurement order m of the light receiver corresponding to the diffraction angle β of the measurement laser is 0th order (vertical position), 1st order (position close to vertical), 2nd order (position slightly inclined from vertical), 3rd order (from vertical). By adopting an appropriate measurement order such as a gradually increasing oblique position), the diffracted light of the measurement laser can be received accurately and efficiently.

  According to the method for observing a fine periodic groove of the present invention, the wavelength λ of the measuring laser and the diffraction of the diffracted light incident on the fine periodic groove at an incident angle α in the vertical plane direction or in an arbitrary oblique direction. By substituting numerical data of the angle β and the measurement order m of the light receiving device that catches the diffracted light into the theoretical formula d (sin α ± sin β) = mλ, the groove interval d of the fine periodic groove can be calculated. Moreover, the production | generation state of a fine periodic groove | channel can be easily confirmed with the output of the light receiver arrange | positioned at the measurement order m. Therefore, for example, the groove interval of the fine periodic grooves provided to reduce the frictional resistance such as the friction reduction between the piston and the cylinder in the engine, the reduction of the rotational friction of the bearing, the reduction of the meshing friction between the gears, etc. It can be observed accurately.

  According to the fine periodic groove observation apparatus of the present invention, when observing the size of the fine periodic groove, for measuring the wavelength λ irradiated to the fine periodic groove at an incident angle α in a vertical plane direction or an arbitrary oblique direction. A laser oscillator, a laser receiver arranged at the measurement order m of the diffraction angle β of the diffracted light of the measurement laser, a monitor device for displaying the received light information of the laser receiver, and the received light information by the theoretical formula d (sin α ± and an arithmetic processing unit for calculating the groove interval d of the fine periodic groove by sin β) = mλ, so that an observation method for accurately determining whether the groove interval of the fine periodic groove is correctly generated or not is provided. Can be implemented. Therefore, for example, the groove spacing of the fine periodic grooves provided to reduce the frictional resistance such as friction reduction between piston and cylinder in the engine, reduction of rotational friction of the bearing, reduction of meshing friction of the gear, etc. is accurate. Observable.

  Furthermore, since the fine periodic groove processing observation method and apparatus include a laser oscillator such as a femtosecond laser for processing, the same operation and effect as the fine periodic groove observation device 100 can be obtained. The output of a femtosecond laser or the like can be feedback controlled by monitoring information obtained by simultaneously monitoring whether the groove interval is good or bad while processing a fine periodic groove on a workpiece, and a fine periodic groove as desired can be processed in advance. Therefore, for example, the process of processing the fine periodic groove applied to each part of the engine and the inspection process for determining whether the fine periodic groove is good or defective can be performed efficiently at the same time, and the productivity can be dramatically improved.

  Further, in the fine periodic groove observation method and apparatus, and the fine periodic groove processing observation method and apparatus, the measurement laser has a fine period on the workpiece surface determined by the wavelength of the femtosecond laser for processing. A He—Ne laser having an optimum wavelength (0.6328 μm), a GaN semiconductor laser close to this wavelength, a femtosecond laser, or the like is selectively used in accordance with the groove interval d of the active grooves. This is because a He—Ne laser, a GaN semiconductor laser, a femtosecond laser, or the like is visible light, so that irradiation of fine periodic grooves on the workpiece surface and the state of diffracted light can be directly observed by the operator's vision. Observation and the operability of the observation device can be further improved. In addition, the consistency with the groove interval d of the fine periodic groove is good and clear observation can be performed.

  Hereinafter, a method and apparatus for observing a fine periodic groove according to the present invention will be described with reference to a first embodiment shown in the drawings. FIG. 1 is a configuration diagram for performing a method for observing a fine periodic groove, FIG. 2 is an enlarged view of diffracted light of the fine periodic groove, FIG. 3 is a diffraction pattern of a CD, and FIGS. FIG. 7 is a monitor photograph of diffracted light.

  First, the fine periodic groove observation device 100 for carrying out the observation method of the present invention will be described with reference to the block diagram of FIG. First, fine periodic grooves (continuous grooves, groove interval = several hundred nm) M1... Processed by a femtosecond laser are provided in advance on the surface of the workpiece W. Of course, it may be a dimple-processed concave groove, or a processing means for generating a fine periodic groove M1 on a metal surface or the like using a laser oscillator for other types of processing. On the surface of the fine periodic groove M1, a measuring laser L1 from the measuring laser oscillator 10 (He—Ne laser having an optimum wavelength λ = 0.6328 μm matching the groove interval d of the fine periodic groove M1 is used. = Several mm) is incident in the vertical plane direction (incident angle α = 0 °) via a plurality of reflecting mirrors 1 and 2 and the condenser lens 3. The diffracted light of the measurement laser L1 is received by a light receiver (for example, a CCD camera or the like) 20 via the condenser lens 4 in the direction of a specific diffraction angle β. As shown in FIG. 2, the measurement order m at which the light receiver 20 is arranged is 0th order (vertical position) m = 0, 1st order (close vertical position) m = 1, 2nd order that provides a large amount of diffracted light. (Slightly oblique position from vertical) m = 2, 3rd order (gradually gradually inclined position from vertical) m = 3 is selected as an appropriate measurement order. The output of the light receiver 20 is input to the computer PC serving as an arithmetic processing unit via the monitor device 1 and the video card 12. With the above basic configuration, the diffracted light L2 of the measurement laser L1 that irradiates the fine periodic groove M1 is projected onto the white paper 22 that is arranged at an appropriate measurement order m. The diffracted light is efficiently received by the light receiver 20, and the generation state of the fine periodic grooves is confirmed by the monitor device 11 or the computer PC serving as the arithmetic processing unit. Of course, both the monitor device 11 and the computer PC as the arithmetic processing unit may be provided side by side, or only one of them may be installed. The blank paper 22 (shown in FIG. 8) may be omitted, and any type of the light receiver 20 (light receiver 20A shown in FIG. 8) can be used. Furthermore, instead of the He—Ne laser, a GaN semiconductor laser or a femtosecond laser having similar characteristics to the He—Ne laser may be used.

  Then, the observation method of the fine periodic groove | channel of this invention is demonstrated. In the observation device 100 of the fine periodic groove M1, when observing the groove interval d of the fine periodic groove M1 processed on the surface of the workpiece W by a femtosecond laser processing machine or the like, A wavelength λ of the measurement laser L1 irradiated at an incident angle α in the vertical plane direction or an arbitrary oblique direction, a diffraction angle β of the diffracted light of the measurement laser L1, and a light receiver that catches the diffracted light of the diffraction angle. It is known that the theoretical formula between the measurement order m of 20 and the groove interval d of the fine periodic groove M1 is d (sin α ± sin β) = mλ. The theoretical formula and software for automatically calculating the theoretical formula are installed in the observation apparatus 100. The observation method of the fine periodic groove of the present invention calculates the diffraction angle β with respect to the groove interval d and the measurement order m from the above theoretical formula, arranges the light receiver 20 at a reasonable measurement order m, and the actual groove interval. Measure and confirm d. Hereinafter, the specifically tested examples will be described.

4 and 5, the workpieces are metal materials SCM415 and S45C, and fine periodic grooves M1 are processed in advance on these surfaces. A measurement (observation) He—Ne laser is incident on the fine periodic groove M1 in the vertical plane direction (incident angle α = 0 °). When the wavelength λ of this measurement laser L1 is 0.6328 μm, the diffracted light characteristic chart of FIG. 4 and the characteristic chart of FIG. 5 are obtained. That is, the groove interval d of the fine periodic groove M1 surface-treated in advance on the workpiece to be processed at the incident angle α = 0 ° is d = 0.6 μm, d = 0.6328 μm, d = 0.7 μm, d = 0. The relationship between the diffraction angle β of the diffracted light and the measurement order m of the photoreceiver 20 that catches the diffracted light when .8 μm, d = 1.0 μm, d = 1.6 μm, and d = 10 μm From d (sin α ± sin β) = mλ, it is calculated as follows.
At d = 0.6 μm, diffraction angle β = no solution.
At d = 0.6328 μm, the diffraction angle β = 0 ° (measurement order m = 0) and the diffraction angle β = 90 ° (measurement order m = 1).
At d = 0.7 μm, the diffraction angle β = ± 64.7 ° (measurement order m = 1).
At d = 0.8 μm, the diffraction angle β = ± 52.2 ° (measurement order m = 1).
At d = 1.0 μm, the diffraction angle β = ± 39.3 ° (measurement order m = 1).
At d = 10 μm, the diffraction angle β = ± 3.6 ° (measurement order m = 1).
At d = 1.6 μm, the diffraction angle β = ± 23.3 ° (measurement order m = 1). become that way.
Based on the calculation result (theoretical value), the shape of the groove interval d of each fine periodic groove M1 was confirmed by placing the light receiver 20 in each measurement order m and attempting observation. As a result of the observation, the diffracted light L2 could be received by the light receiver 20 arranged at each diffraction angle β. From this observation result, it was clarified that the theoretical value and the observed value almost coincided with each other, and it was proved that the periodic groove observation device and the function and performance that can be sufficiently used as the observation method were exhibited.

FIG. 3 illustrates an observed diffraction pattern in the case where the work piece is a music CD disk in the first embodiment.
FIG. 3A shows the surface of the CD disc provided with the fine periodic grooves M1. FIG. 3B is an enlarged view of a diffraction pattern at a specific place surrounded by a circle. As measurement orders, m = 0, m = 1, m = 2, m = -1, and m = -2. There are places. This diffracted light is projected onto the white paper P as shown in FIG. Therefore, diffracted light can be sensed and observed by arranging the light receiver 20 at any of the five locations. The surface to be a recording medium of the music CD disk is not a complete fine periodic groove M1, but has a spiral shape in which a large number of irregular dimples are processed on a flat surface and carved in a double row. It appears as if a periodic groove is formed. When this spiral pseudo periodic groove is irradiated with the measurement laser L1, diffracted light L2 is obtained. The diffracted light L2 was photographed as shown in FIG. As can be seen from this photograph, extremely bright diffracted light was observed at the measurement order m = 1. The intense portion of light seen in the center of the photograph is the diffracted light of the measurement order m = 1. Seen around is scattered light, which is noise due to the shape of the workpiece to be irradiated. If strong diffracted light near the center shown in the photograph is extracted as position information, information on the diffraction angle can be obtained. Periodic groove interval information can be obtained from this diffraction angle information. As described above, according to the method and apparatus for observing a fine periodic groove of the present invention, not only the observation of a straight fine periodic groove M1, but also a spiral-like pseudo signal as seen on a music CD disc, for example. It was proved that accurate observation was possible even in a typical fine periodic groove (dimple groove).

In the second embodiment shown in FIG. 6, the workpiece to be processed in the second embodiment is a metal material S45C, and the fine periodic groove M1 is processed in advance on this surface. The measurement He-Ne laser L1 irradiated to the fine periodic groove M1 has, for example, a diffracted light characteristic diagram and a diffracted light, which are theoretical values when the incident angle α is 45 ° and the wavelength λ is 0.5435 μm. A characteristic chart is obtained from the theoretical formula d (sin α ± sin β) = mλ. That is, in the above theoretical formula, the diffraction angle β of the diffracted light when the groove interval d of the fine periodic groove M1 surface-treated in advance on the workpiece is d = 0.3 μm to 0.9 μm, and the diffracted light The relationship with the measurement order m of the light receiver 20 that catches the above is listed.
At d = 0.3 μm, diffraction angle β = 45 ° (measurement order m = 0), no solution (measurement order m = 1).
At d = 0.4 μm, diffraction angle β = 45 ° (measurement order m = 0), diffraction angle β = −40.7 ° (measurement order m = 1).
At d = 0.5 μm, diffraction angle β = 45 ° (measurement order m = 0), diffraction angle β = −22.3 ° (measurement order m = 1).
At d = 0.6 μm, diffraction angle β = 45 ° (measurement order m = 0) and diffraction angle β = −11.5 ° (measurement order m = 1).
At d = 0.7 μm, diffraction angle β = 45 ° (measurement order m = 0), diffraction degree β = −4.0 ° (measurement order m = 1), diffraction angle β = −57.8 ° (measurement order) m = 2).
At d = 0.8 μm, diffraction angle β = 45 ° (measurement order m = 0), diffraction angle β = 1.6 ° (measurement order m = 1), diffraction angle β = -40.7 ° (measurement order m = 2).
At d = 0.9 μm, diffraction angle β = 45 ° (measurement order m = 0), diffraction angle β = 5.9 ° (measurement order m = 1), diffraction angle β = -30.1 ° (measurement order m = 2). It became like this.
Based on the calculation result (theoretical value), the shape of the groove interval d of each fine periodic groove M1 was confirmed by placing the light receiver 20 in each measurement order m and attempting observation. As a result of the observation, the diffracted light L2 could be received by the light receiver 20 arranged at each diffraction angle β. From this observation result, it was clarified that the theoretical value and the observed value almost coincided with each other, and it was proved that the periodic groove observation device and the function and performance that can be sufficiently used as the observation method were exhibited. In addition, the above observation apparatus requires few components and is considered to be a practical apparatus used at the production site. Have.

  As described above, according to the fine periodic groove observation method and apparatus according to the first embodiment of the present invention, the following effects are exhibited. First, according to the observation method of the fine periodic groove M1, the wavelength λ of the measurement laser incident on the fine periodic groove at a predetermined incident angle α, the diffraction angle β of the diffracted light, and the diffracted light are caught. Since the relationship between the measurement order m of the photoreceiver and the groove interval d of the fine periodic groove is clarified by the theoretical formula d (sin α ± sin β) = mλ, the measurement order is arranged in a predicted order. The generation state of the fine periodic groove can be reliably confirmed by the photoreceiver. Thereby, for example, the good / bad determination of the fine periodic groove formed in each part of the engine cylinder, piston ring, bearing, etc. can be made by directly observing the diffracted light from the fine periodic groove.

  In addition, according to the observation device 100 for the fine periodic groove, when observing the groove of the fine periodic groove, the laser oscillator 10 for measuring the wavelength λ that irradiates the fine periodic groove with the incident angle α, and the measurement laser L1. The laser receiver 20 arranged at the measurement order m of the diffraction angle β of the diffracted light, the monitor device 11 for displaying the light reception information of the laser receiver, and the light reception information are finely expressed by the theoretical formula d (sinα ± sinβ) = mλ. Since an arithmetic processor PC for calculating the groove interval d of the periodic grooves is provided, an observation method for determining whether the fine periodic grooves are good or defective can be accurately implemented. Therefore, according to the present observation apparatus 100, the theoretical value and the observation value almost coincide with each other, so that the value as a practical apparatus at the production site can be exhibited.

  Further, the measurement laser L1 selectively uses a He—Ne laser corresponding to the groove interval d of the fine periodic groove determined by the wavelength of the processing femtosecond laser LO, and receives light corresponding to the diffraction angle β. The measuring position is selected from 0th order (vertical position), 1st order (position close to vertical), 2nd order (slightly oblique position from vertical), and 3rd order (slightly oblique position from vertical). By disposing in this manner, the diffracted light of the measuring laser can be received accurately and efficiently, and the generation state of the fine periodic grooves and the good / bad condition can be easily confirmed. More specifically, if the measurement laser employs, for example, a visible light He-Ne laser having a wavelength λ = 0.6328 μm, the fineness of the workpiece surface determined by the wavelength of the femtosecond laser for processing is used. Optimal observation can be made clearly and directly with respect to the groove interval d of the periodic grooves (for example, an appropriate wavelength within the range of 0.6 μm to 1.6 μm). That is, with lasers other than those described above, the wavelength is extremely short or long with respect to the groove interval d (for example, 0.6 μm to 1.6 μm) of the fine periodic groove, making it impossible to clearly observe the groove interval. It becomes.

  The present invention is not limited to the observation device 100 for a fine periodic groove according to the first embodiment. The fine periodic groove processing observation apparatus 200 and the processing observation method using this apparatus according to the second embodiment shown in FIG. 8 are not limited to the measurement laser oscillator 10 in the fine periodic groove observation apparatus 100 described above. And a femtosecond laser oscillator 30. Of course, other types of laser oscillators for processing may be used. The lasers LO and L1 from these two oscillators 10 and 30 are introduced, and a light receiver for sensing the diffracted light L2 of the measurement laser L1 is provided in one observation head 40 so that processing and observation are performed simultaneously. Is. The configuration of the observation head 40 is that a laser oscillator 30 that processes the fine periodic groove M1 by vertically irradiating the surface of a workpiece (for example, engine cylinder) W with a femtosecond laser LO (incident angle α = 0 °). A measurement laser oscillator 10 that oscillates a measurement laser L1 having a wavelength λ that is superimposed on the femtosecond laser by a half mirror 21 and is vertically incident on the fine periodic groove (incident angle α = 0 °), and the measurement A white plate (white paper) 22 is arranged at the measurement order m of the diffraction angle β of the diffracted light L2 that bounces off the fine periodic groove M1. It comprises a fiberscope 20A for receiving light that detects the diffracted light projected on the white plate 22. Of course, the diffracted light L2 may be directly detected by the light receiving fiberscope 20A. The received light information from the fiberscope 20A is connected to the monitor device 11 or a computer PC having an arithmetic processing unit for calculating the groove interval d and the like of the fine periodic groove M1 by the theoretical formula d (sin α ± sin β) = mλ. ing. In the second embodiment, the white plate (blank paper) 22 is disposed as an integral configuration within the tip of the observation head 40. Further, the surface of the workpiece W may be irradiated with a femtosecond laser LO in an arbitrary oblique direction. In order to efficiently display the diffraction light L2, the white plate 22 and the fiber scope 20A The arrangement is changed as appropriate.

  According to the fine periodic groove processing observation apparatus 200 having this configuration and this method, the fine periodic groove M1 is first processed by vertically irradiating the surface of the workpiece W with the femtosecond laser LO. At the same time, a measurement laser L1 having a wavelength λ is oscillated from the measurement laser oscillator 10 on the femtosecond laser LO and is superimposed on the half mirror 21 so as to be perpendicularly incident on the fine periodic groove M1 (incident angle α = 0 °). ) Accordingly, the measurement laser L1 is reflected when irradiated to the fine periodic groove, and the diffracted light L2 is projected as diffracted light onto the white plate 22 arranged at the measurement order m of the diffraction angle β. This diffracted light is received by the receiving fiberscope 20A. The received light information received by the fiberscope 20A can be directly observed as diffracted light by the monitor device 11. Further, the light reception information from the fiberscope 20A is subjected to calculation processing of the groove interval d of the fine periodic groove by the theoretical formula d (sin α ± sin β) = mλ stored in the computer PC having the function of an arithmetic processor. The processing contents are displayed. Thereby, it is simultaneously confirmed whether or not the groove intervals of the fine periodic grooves are correctly generated while machining the fine periodic grooves by the femtosecond laser on the cylinder surface of the workpiece W. That is, the output of the femtosecond laser is feedback-controlled so that the fine periodic groove is generated with a precise processing dimension based on the monitoring information while monitoring the groove interval. Thereby, the fine periodic groove as desired in advance can be processed and observed and inspected.

  The effectiveness of adopting the femtosecond laser LO for processing the fine periodic groove M1 will be listed. First, femtosecond laser processing enables fine processing of fine shapes with few burrs due to the ablation effect. Transparent materials can also be processed. Able to process nano-sized periodic grooves and dimples. This groove does not depend on the spot diameter of the laser, but depends on the laser wavelength and fluence. The groove has a depth of about 200 nm, and the groove interval is processed to have a width that is about the same as the laser wavelength to about half. Such periodic grooves and dimple friction reduction can be used for various parts processing. Thus, for example, as a measure for improving the fuel efficiency of automobiles, the friction between the piston and the cylinder is reduced by observing while generating the fine periodic groove M1 in the cylinder, piston ring, bearing, and gear in the engine. The processing and observation of the fine periodic grooves that are performed to reduce the frictional resistance such as reduction and reduction of gear meshing friction to the limit are performed in real time.

  The fine periodic groove processing and observation apparatus 200 of the second embodiment and the effect of this method are that the fine periodic groove observation apparatus 100 includes a laser oscillator 30 such as a femtosecond laser. In addition to the same operation and effect as the groove observation device 100, feedback control of the output of the femtosecond laser and the like is performed by monitoring information that simultaneously monitors the goodness and badness of the groove interval while processing a fine periodic groove on the workpiece. It is possible to process fine periodic grooves as desired in advance. Thus, for example, the process of machining the fine periodic grooves applied to each part of the engine and the inspection process for determining whether the fine periodic grooves are good or defective can be performed efficiently at the same time, and the productivity can be dramatically improved. .

  The fine periodic groove observation method and apparatus, the fine periodic groove processing observation method and the processing observation apparatus thereof according to the present invention are the cylinder and piston rings, bearings, gears, etc. It is not limited to the tribological effect inside the engine for the inspection object. Accordingly, a wide range of workpieces in all industrial fields in which fine periodic grooves are generated on the surface can be used. Therefore, the main purpose of the present invention is to promote the technological development of parts processing that contributes to the energy-saving effect and life-proof effect by reducing the energy loss by reducing the sliding friction resistance of various industrial machines, It greatly contributes to global warming prevention measures. Further, in the fine periodic groove observation method and apparatus, and the fine periodic groove processing observation method and processing observation apparatus constituting the present invention, the design change of each constituent member and the constituent members within the gist of the invention It is possible to freely change or replace the member.

It is a block diagram which shows the 1st Embodiment of this invention and implements the observation method of a fine periodic groove | channel. FIG. 2 is a magnified view of diffracted light of a fine periodic groove in the first embodiment of the present invention. FIG. 2 shows a first embodiment of the present invention and is a diffraction pattern diagram of a CD. FIG. 5 is a diffracted light characteristic diagram of the measurement laser irradiated to the fine periodic groove in the first embodiment of the present invention. It is a characteristic chart of the laser for measurement which showed the 1st Embodiment of this invention and irradiated to the fine periodic groove | channel. It is a diffracted light characteristic chart of a measurement laser which showed a 1st embodiment of the present invention and irradiated to a fine periodic slot. It is a monitor photograph of the diffracted light which showed the 1st Embodiment of this invention and was irradiated to the fine periodic groove | channel. It is a block diagram of the processing observation apparatus of the fine periodic groove | channel which shows the 2nd Embodiment of this invention.

Explanation of symbols

1, 2 Reflection mirror
3,4 Condensing lens 10 Laser oscillator for measurement 11 Monitor device 12 Video card
20 Receiver 20A Fiberscope 21 Half mirror 22 White board (blank paper)
30 Femtosecond laser oscillator 40 Observation head 100 Fine periodic groove observation device 200 Fine periodic groove processing observation device d Groove interval LO Femtosecond laser L1 Measurement laser L2 Diffracted light M1 Fine periodic groove m Measurement order PC Computer (Calculation processing part)
α Incident angle β Diffraction angle W Workpiece (cylinder)
λ Measurement laser wavelength

Claims (8)

  When observing a fine periodic groove whose surface is processed by a femtosecond laser processing machine or the like, an incident angle α and a wavelength λ of the measurement laser incident on the fine periodic groove from a vertical plane direction or an arbitrary oblique direction And a theoretical expression d (sin α ± sin β) of the diffraction angle β of the diffracted light of the measurement laser, the measurement order m of the light receiver that catches the diffracted light of the diffraction angle, and the groove interval d of the fine periodic groove ) = A method for observing a fine periodic groove, wherein a light receiver is arranged at a measurement order m obtained from mλ, and a groove interval d is measured and confirmed.   When observing a micro periodic groove whose surface is processed by a femtosecond laser processing machine or the like, the micro periodic groove is irradiated at an incident angle α in a vertical plane direction or an arbitrary oblique direction and for measuring a specific wavelength λ. An oscillator that oscillates a laser; a laser receiver disposed at a measurement order m of the diffraction angle β of the diffracted light of the measurement laser irradiated to the fine periodic groove from the measurement laser oscillator; and light reception information from the laser receiver And a processing unit for calculating the groove interval d of the fine periodic groove according to the theoretical formula d (sin α ± sin β) = mλ.   The measurement laser is a He—Ne laser, a GaN semiconductor laser, a femtosecond laser, or the like, and the measurement order m of the light receiver corresponding to the diffraction angle β is a measurement order such as 0th order, first order, second order, third order, and the like. The method for observing a fine periodic groove according to claim 1, wherein:   The measurement laser is a He—Ne laser, a GaN semiconductor laser, a femtosecond laser, or the like, and the measurement order m of the light receiver corresponding to the diffraction angle β is a measurement order such as 0th order, first order, second order, third order, and the like. The observation device for fine periodic grooves according to claim 2, wherein   The surface of the workpiece is irradiated with a femtosecond laser vertically or from an arbitrary oblique direction to process the fine periodic groove, and at the same time, the femtosecond laser is overlapped with a half mirror to the fine periodic groove. The incident angle α and its wavelength λ of the measuring laser incident from the vertical plane direction or an arbitrary oblique direction, the diffraction angle β of the diffracted light of the measuring laser, and the light receiver that catches the diffracted light of the diffracted angle And measuring and confirming the groove interval d by placing a photoreceiver at the measurement order m obtained from the theoretical formula d (sin α ± sin β) = mλ between the measurement order m of the above and the groove interval d of the fine periodic groove. A processing method for processing fine periodic grooves.   A laser oscillator that processes a fine periodic groove by irradiating a surface of a workpiece with a femtosecond laser or the like from an oblique direction or an arbitrary oblique direction, and the fine periodic groove superimposed on the femtosecond laser or the like with a half mirror. A measurement laser oscillator that irradiates a measurement laser having a specific wavelength λ while being irradiated with an incident angle α in a vertical plane direction or an arbitrary oblique direction with respect to the above, and the fine periodic groove is irradiated with the measurement laser Receiving fiberscope arranged at the measurement order m of the diffraction angle β of the reflected diffracted light and a monitor device for displaying light receiving information from the fiberscope or the above-mentioned theoretical formula d (sinα ± sinβ) = mλ A processing observation apparatus for fine periodic grooves, comprising: an arithmetic processing unit that calculates the groove interval d of the grooves.   The measurement laser is a He—Ne laser, a GaN semiconductor laser, a femtosecond laser, or the like, and the measurement order m of the light receiver corresponding to the diffraction angle β is a measurement order such as 0th order, first order, second order, third order, and the like. The method for observing the processing of a fine periodic groove according to claim 5, wherein:   The measurement laser is a He—Ne laser, a GaN semiconductor laser, a femtosecond laser, or the like, and the measurement order m of the light receiver corresponding to the diffraction angle β is a measurement order such as 0th order, first order, second order, third order, and the like. The processing observation apparatus for fine periodic grooves according to claim 6, wherein:

Images