JP2015230253A - Optical nondestructive inspection method and optical nondestructive inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical nondestructive inspection method and an optical nondestructive inspection apparatus which are capable of, more easily, in a shorter time, and more properly inspecting a pressure-welding state of pressure-welding parts of two work-pieces coupled to each other by pressure-welding but without being deposited, in which the pressure-welding part on one work-piece and the pressure-welding part on the other work-piece are configured of a conductive member.SOLUTION: The optical nondestructive inspection method includes: a heating step of setting a measurement spot SP on a surface of a work-piece, and irradiating the measurement spot with a heating laser using a heating laser source 21, infrared ray detection means 31, a correction laser source 71, correction laser detection means 71R, and control means 50; a temperature rise characteristics acquisition step of acquiring temperature rise characteristics of the measurement spot according to a temperature and a heating period of the measurement spot based on an infrared ray emitted from the measurement spot and reflectance rate of the correction laser; and a determination step of determining the quality of pressure-welding states including a contact area and a contact pressure on pressure-welding parts 91B, 92B based on the temperature rise characteristics.

Description

  The present invention provides the pressure contact portion of two workpieces joined by pressure welding without being welded, wherein the pressure contact portion in one workpiece and the pressure contact portion in the other workpiece are each formed of a conductive member. The present invention relates to an optical nondestructive inspection method and an optical nondestructive inspection apparatus for determining a pressure contact state in a section.

  In recent years, control units of various sizes according to applications such as automobiles and home appliances have been developed, and various electronic circuit boards are used in the control units. Is assembled. For example, as shown in FIG. 1, a through hole 91 having an inner wall 91 </ b> B made of copper foil or tin plating is formed in the substrate 90, and a press-fit pin 92 (contact) is inserted into the through hole 91 (press-fit). ). In this case, the inner wall 91B (pressure contact portion) of the through hole 91 is a conductive member such as copper foil or tin plating, and the elastic deformation portion 92B (pressure contact portion) of the press-fit pin 92 is also a conductive member. The outer diameter of the elastic deformation portion 92B of the press-fit pin 92 is set to be slightly larger than the inner diameter of the inner wall 91B. The elastic deformation portion 92B of the press-fit pin 92 is deformed when inserted into the through hole 91 and the outer diameter thereof is reduced, and is brought into a pressure contact state with the inner wall 91B of the through hole 91 by an elastic restoring force. The contact area and the contact pressure of the pressure contact portion in this pressure contact state affect the conductivity at the pressure contact portion. For example, when the elastic deformation portion 92B of the press-fit pin 92 is in an abnormally deformed state and the contact area with the inner wall 91B of the through hole 91 is extremely small, or when the contact pressure is extremely low, the conductivity decreases. In some cases, desired conductivity cannot be ensured (conductivity failure occurs). Further, when the press-fit pin 92 is inserted into the through hole 91, the inner wall 91B of the through hole 91 may be shaved and the desired conductivity may not be ensured. Therefore, various methods and various apparatuses for inspecting the insertion state and press-contact state of the press-fit pin 92 inserted into the through hole 91 are disclosed.

  For example, in Patent Document 1, an inspection hole which is a through hole is formed at a position which is a part of a press-fit pin and protrudes from the substrate when inserted into the insertion hole of the substrate. There is described a press-fit terminal insertion state inspection apparatus that detects the position of an inspection hole and determines whether the insertion state is good or not before inserting a press fit pin into a board insertion hole. At the time of detection, the press-fit pin is irradiated with light from the light emitting part to capture a transmission image or a reflection image, and the position of the inspection hole in the image captured before insertion and the image captured after insertion The insertion state of the press fit pin is inspected from the position of the inspection hole.

  Patent Document 2 discloses a reflected wave receiver that abuts a vibrator of an ultrasonic oscillator on the tip of a press-fit pin inserted into an insertion hole of a substrate and receives a reflected wave from the tip of the press-fit pin. From the conductor (the land of the through hole in which the press-fit pin is inserted) that is opposite to the tip of the press-fit pin with respect to the insertion hole and is continuous with the insertion hole to which the press-fit pin is pressed. There is described a press-fit pin bonding state inspection device in which a propagation wave receiver for receiving a propagation wave is connected. In the inspection, pass / fail is determined by comparing at least one of the reference reflected wave waveform and the reference propagation wave waveform in the case of a press-fit pin in a good bonded state.

Japanese Patent No. 5175681 JP 2010-86868 A

  In the invention described in Patent Document 1, the insertion state of the press-fit pin into the insertion hole of the substrate can be determined by an image, but the press-contact state between the press-fit pin and the insertion hole cannot be inspected. There is a possibility that an electrical continuity test has not been completed. Even if the press-fit pin is inserted at the correct position, the electrical conduction state may not be a desired conduction state due to the deformation state of the press-fit portion of the press-fit pin, the scraped state of the inner wall of the insertion hole of the substrate, or the like.

  In the invention described in Patent Document 2, the press-contact state between the press-fit pin and the insertion hole can be inspected. For the inspection, the vibration of the ultrasonic oscillator is placed near the tip of the press-fit pin or the press-fit pin. Since the child, the pin for receiving the propagation wave, and the like must be fixed at the desired position in the desired state, the inspection is not easy.

  The present invention was devised in view of the above points, and is a press-contact portion of two workpieces joined by press-contact without being welded. The press-contact portion in one workpiece and the press-contact in the other workpiece Provided are an optical nondestructive inspection method and an optical nondestructive inspection apparatus capable of inspecting a press contact state in a press contact portion composed of conductive members with each other more easily, in a shorter time, and more appropriately. This is the issue.

  In order to solve the above problems, the optical nondestructive inspection method and the optical nondestructive inspection apparatus according to the present invention take the following means. First, the first invention of the present invention is a pressure contact portion of two workpieces joined by pressure welding without welding, and the pressure contact portion in one workpiece and the pressure contact portion in the other workpiece are electrically conductive to each other. An optical non-destructive inspection method for determining a pressure contact state in the pressure contact portion constituted by a member, wherein a measurement spot is formed on the surface of one work in the vicinity of the pressure contact portion and including the pressure contact portion. A heating laser light source that emits a heating laser having a predetermined laser wavelength, an infrared detecting means capable of detecting infrared light having a predetermined infrared wavelength, and a correction laser having a smaller output than the heating laser A correction laser light source that emits light, a correction laser detection means that can detect the correction laser, and the heating laser light source and the correction laser light source. And a control means for capturing a detection signal from the infrared detection means and the correction laser detecting means is used. Then, the heating laser light source is controlled from the control means, and the measurement spot is heated by irradiating the measurement spot with the heating laser adjusted to an amount of heat to be heated without destroying the workpiece. In the heating step, while performing the heating in the heating step, the control means detects infrared rays radiated from the measurement spots using the infrared detection means to determine the temperature of the measurement spots, and according to the heating time. Based on the temperature rise characteristic obtaining step for obtaining the temperature rise characteristic which is the temperature rise state of the measurement spot and the temperature rise characteristic of the measurement spot which is a heating point affected by the amount of heat conduction, the control means Determining the quality of the pressure contact state including the contact area and the contact pressure at the pressure contact portion of the two workpieces, In the temperature increase characteristic acquisition step, when the control means obtains the temperature of the measurement spot, the correction laser light source is controlled to irradiate the measurement spot with the correction laser having a predetermined output, and the measurement The correction laser detection means, which is the correction laser reflected at the spot, is detected by the correction laser detection means to obtain characteristics relating to the reflectance at the measurement spot, and the predetermined detection detected by the infrared detection means It is an optical nondestructive inspection method that corrects the temperature of the measurement spot obtained based on infrared rays of a wavelength based on the characteristic relating to the reflectance.

  Next, a second invention of the present invention is the optical nondestructive inspection method according to the first invention, wherein at least one of the press contact portions of the two workpieces includes the press contact portion of the two workpieces. An alloy or a metal having a melting point lower than the melting point of each conductive member is plated, and in the heating step, the heating laser light source is controlled from the control means to heat the workpiece without destroying it. If the measurement spot is irradiated with the heating laser having an output adjusted to an amount of heat that is less than the melting point of the plating, and is determined to be non-defective in the determination step, the control laser A new heating level that is an amount of heat that heats the output of the light source without destroying the workpiece and that is adjusted to an amount of heat that is equal to or higher than the melting point of the plating. An optical welding step, wherein the welding is performed by melting the plating by irradiating the measurement spot with the new heating laser for a predetermined time and welding the two workpieces at the pressure contact portion. This is a non-destructive inspection method.

  Next, a third invention of the present invention is the optical nondestructive inspection method according to the first invention, wherein at least one of the press contact portions of the two workpieces includes the press contact portion of the two workpieces. An alloy or a metal having a melting point lower than the melting point of each conductive member is plated, and in the heating step, the heating laser light source is controlled from the control means to heat the workpiece without destroying it. And an optical nondestructive inspection method in which the measurement spot is irradiated with the heating laser having an output adjusted to a heat quantity equal to or higher than the melting point of the plating.

  Next, a fourth invention of the present invention is the optical nondestructive inspection method according to any one of the first to third inventions, wherein in the determination step, the control means The time from the start of irradiation of the heating laser to the measurement spot to the time when the temperature rise characteristic becomes a thermal equilibrium state where the temperature rise state is not more than a predetermined rise state in the temperature rise characteristic is a first reference set in advance. If the contact area does not fall between the threshold value and the second reference threshold value, the contact area is out of the desired size range, or the contact pressure is out of the desired pressure range. This is an optical nondestructive inspection method for determining that the product is a defective product.

  Next, a fifth invention of the present invention is an optical nondestructive inspection apparatus for executing the optical nondestructive inspection method according to any one of the first to fourth inventions, wherein the heating Laser light source and parallel light incident from one side along the optical axis is condensed toward the measurement spot set as a focal position and emitted from the other side, and emitted from the measurement spot and Condensing collimating means that converts reflected light incident from the other side into measurement light that is parallel light along the optical axis and emits it from one side, and converts the heating laser into parallel light Corresponding to the heat radiated from the measurement spot, which is the infrared ray contained in the measurement light, and the laser beam guiding means for heating led to one side of the condensing collimating means In front of the infrared of the predetermined infrared wavelength Infrared light guiding means for guiding to the infrared detecting means, the correction laser light source, the correction laser is converted into parallel light, and at least a part of the correction laser converted into parallel light is overlapped with the measurement light. Correction laser light guiding means for guiding to the measurement spot, correction laser detection means, and at least a part of the reflection correction laser reflected in the measurement spot and included in the measurement light is corrected. An optical non-destructive inspection apparatus comprising: a reflected laser light guiding means that leads to a laser detecting means for use; and the control means.

  According to the first invention, for example, the two workpieces are a press-fit pin and a through hole, and the press-fit pin (conductive member) is inserted into the inner wall (conductive member) of the through hole. In a state of being bonded by pressure welding without being welded, a measurement spot is set at the tip of the press-fit pin, and a laser for heating is irradiated to the measurement spot, and a temperature rise characteristic is obtained. It is possible to appropriately determine whether there is an abnormality in the contact area and the contact pressure. Moreover, since the temperature rise characteristic can be obtained in a non-contact manner with respect to the two workpieces, the determination can be made more easily. Further, by using a heating laser with an appropriate output, a desired temperature rise characteristic can be obtained in a very short time. That is, it can be more easily inspected in a shorter time more appropriately whether or not the desired electrical conduction state (pressure contact state). In addition, more accurate temperature rise characteristics can be achieved by irradiating the measurement laser with the correction laser, detecting the reflection correction laser reflected at the measurement spot, and determining the reflectance-related characteristics to correct the measurement spot temperature. Can be obtained.

  According to the second invention, after confirming that the two workpieces joined by pressure welding without being welded are in a desired pressure welding state, in the welding step, the pressure welding portion can be appropriately and easily performed. Can be welded. Moreover, the plating shaving part and the fine whiskers made of tin or the like can be melted to achieve a more reliable pressure contact state (electric conduction state).

  According to the third aspect, since the heating step and the welding step in the second aspect can be performed simultaneously, the pressure contact state can be inspected in a shorter time.

  According to the fourth aspect of the invention, it is determined that the contact area or the contact pressure is out of the desired area range or the desired pressure range by determining based on the time until the thermal equilibrium state in the temperature rise characteristic is reached. It can be judged appropriately.

  According to the fifth invention, the optical nondestructive inspection apparatus for executing the optical nondestructive inspection method according to any one of the first to fourth inventions can be appropriately realized.

It is a perspective view explaining the example of the external appearance of each workpiece | work before couple | bonding two workpiece | work (a press fit pin and a through hole) which are measurement objects. It is II-II sectional drawing at the time of inserting a press fit pin in the through hole in FIG. FIG. 3 is an enlarged view of a part III in FIG. 2, illustrating a position of a measurement spot, radiation of heat rays (infrared rays), a state in which heat is conducted from the measurement spot to the press contact part, and the like. It is a figure explaining the example of a structure of the optical nondestructive inspection apparatus of 1st Embodiment. It is a figure explaining the example of a structure of the optical nondestructive inspection apparatus of 2nd Embodiment. It is a figure explaining the example of a structure of the optical nondestructive inspection apparatus of 3rd Embodiment. It is a figure explaining the example of a structure of the optical nondestructive inspection apparatus of 4th Embodiment. It is a flowchart explaining the example of the process sequence (the 1) of an optical nondestructive inspection method. It is a figure explaining a reflectance characteristic. It is a figure explaining the relationship between an infrared wavelength, infrared energy, and temperature. It is a figure explaining the example of the temperature rise characteristic by correction | amendment temperature corrected using the emissivity calculated | required from the reflectance. It is a figure explaining the normalized temperature rise characteristic which compressed and normalized the temperature rise characteristic to the temperature direction. It is a figure explaining the normalization temperature rise characteristic which extended the temperature rise characteristic in the temperature direction, and was normalized. It is a figure which shows the example of the state which accumulated the normalization ideal temperature rise characteristic, the normalization lower limit temperature rise characteristic, and the normalization upper limit temperature rise characteristic. It is a figure explaining the example which displayed the information regarding the determination result of the press-contact state of a measuring object on the display means. It is a flowchart explaining the example of the process sequence (the 2) of an optical nondestructive inspection method.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing.
● [Example of measurement object (Figs. 1 to 3)]
An example of the measurement object will be described with reference to FIG. FIG. 1 shows an example of the appearance of through holes 91 and press-fit pins 92 formed in a substrate 90 that is a measurement object. In the description of the present embodiment, the through hole 91 and the press-fit pin 92 correspond to two workpieces that are measurement objects. The through hole 91 has an inner wall 91B which is an inner wall portion of the through hole and a land 91A provided at an edge of the through hole with respect to the through hole formed in the substrate 90. The lands 91A are provided on the front and back of the substrate 90 and connected to the inner wall 91B. For example, the lands 91A are connected to other lands for mounting electronic components on the substrate 90 by wiring printed on the substrate. ing. The inner wall 91B and the land 91A are formed of a conductive member (for example, copper foil, solder plating, etc.). In the present embodiment, the inner wall 91 </ b> B corresponds to the pressure contact portion in the through hole 91.

  The press-fit pin 92 is formed of a conductive member, and has a tip portion 92A, an elastic deformation portion 92B, a base portion 92C, and the like. The width of the elastic deformation portion 92B is set to be slightly larger than the inner diameter of the inner wall 91B of the through hole 91. When the through hole 91 is inserted from the tip end portion 92A of the press-fit pin 92 to the elastic deformation portion 92B, the elastic deformation portion 92B is elastic. The deforming portion 92B is elastically deformed and press-contacts the inner wall 91B with a restoring force of elastic deformation. As a result, the press-fit pin 92 is coupled to the through hole 91 in a state of being pressed without being welded (see FIGS. 2 and 3). In the present embodiment, the elastic deformation portion 92 </ b> B corresponds to the press contact portion in the press fit pin 92.

  If the pressure contact portion (elastic deformation portion 92B) of the press-fit pin 92 is not in an appropriate pressure contact state with respect to the pressure contact portion (inner wall 91B) of the through hole 91, a desired electrical conduction state cannot be ensured and the conduction failure. It may become. For example, when the press-fit pin 92 is deformed into an abnormal shape in the inner wall 91B and the contact area of the press contact portion is abnormally small, or when the contact pressure of the press contact portion is abnormally small, or the inner wall 91B is greatly cut into the elastic deformation portion 92B. In some cases, a conduction failure such as an abnormal increase in electrical resistance may occur.

  In order to determine whether the pressure contact state between the inner wall 91B of the through hole 91 and the elastic deformation portion 92B of the press-fit pin 92 is a desired state (desired contact area and desired contact pressure), heat propagation It can be determined by the state. For example, in FIG. 3, the measurement spot SP is set at the tip of the press-fit pin 92 that is the surface of one workpiece in the vicinity of the press contact portion and the surface of the conductive member including the press contact portion. Then, the measurement spot SP is irradiated with a heating laser to heat the measurement spot SP in a non-contact manner. Then, the temperature of the measurement spot SP gradually increases, and heat is propagated from the measurement spot SP via the press-fit pin 92 and the inner wall 91B. Further, heat rays (infrared rays) corresponding to the increased temperature are emitted from the press-fit pins 92 and the through holes 91 including the measurement spot SP. Then, by measuring the radiated heat ray (infrared ray) in a non-contact manner and obtaining the temperature of the measurement spot SP, the propagation state of heat radiated through the press contact portion (indicated by a dotted line in FIG. 3) is obtained. It can measure indirectly and can determine the contact area and contact pressure of a press-contact part.

  Further, although the temperature of the measurement spot SP gradually increases, when the temperature reaches a saturation temperature at which the heating amount and the heat radiation amount coincide with each other, the temperature increase stops and becomes a substantially constant temperature even if heating is continued. Here, when the contact area at the pressure contact portion is relatively large or when the contact pressure is relatively large, the amount of heat conduction is large, so that the temperature rise according to the heating time is relatively slow and the saturation temperature is relatively low. Further, when the contact area at the pressure contact portion is relatively small or when the contact pressure is relatively small, the amount of heat conduction is small, so that the temperature rise according to the heating time is relatively steep and the saturation temperature is relatively high. Therefore, the measurement spot SP is irradiated with the heating laser to measure the temperature rise characteristic as shown in FIG. 11, and based on the temperature rise characteristic, whether or not the contact area and the contact pressure at the press contact portion are within the allowable range. It is possible to determine whether the pressure contact state is good or not. In the following description, an example of the configuration (first embodiment to fourth embodiment) of an optical nondestructive inspection apparatus capable of determining the quality of the above-described pressure contact state, and an optical nondestructive inspection method Details will be described.

[Example of the configuration of the optical nondestructive inspection apparatus 1A in the first embodiment (FIG. 4)]
FIG. 4 shows an example of the configuration of the optical nondestructive inspection apparatus 1A according to the first embodiment, and FIG. 5 shows an example of the configuration of the optical nondestructive inspection apparatus 1B according to the second embodiment. FIG. 6 shows an example of the configuration of the optical nondestructive inspection apparatus 1C of the third embodiment, and FIG. 7 shows an example of the configuration of the optical nondestructive inspection apparatus 1D of the fourth embodiment. In the first to fourth embodiments, each component is the same, but the arrangement position and direction (reflection direction and transmission direction) of each component are different. First, the configuration of the optical nondestructive inspection apparatus 1A according to the first embodiment shown in FIG. 4 will be described.

  The optical nondestructive inspection apparatus 1A shown in FIG. 4 includes a condensing collimating means 10, a heating laser light source 21, a heating laser collimating means 41, a heating laser selective reflection means 11A, an infrared detection means 31, and an infrared selective reflection means 12B. , Infrared condensing means 51, correction laser light source 71, correction laser detection means 71R, beam splitter 17A, correction laser collimating means 81, reflection laser condensing means 81R, control means 50, storage means 60, etc. ing.

  The condensing collimating means 10 directs the parallel light incident from one side along its own optical axis (from above in the example of FIG. 4) toward the measurement spot SP set on the measurement object as a focal position. The light is condensed and emitted from the other side (from below in the example of FIG. 4). In addition, the condensing collimating means 10 radiates and reflects light incident from the other side from the measurement spot SP (which is a focal position) to the first measurement light L11 which is parallel light along its own optical axis. Convert and emit from one side. The condensing collimating means 10 can be constituted by a condensing lens that transmits light and refracts it. However, since the condensing collimating means 10 handles light having a plurality of different wavelengths, it is not preferable for a condensing lens that generates chromatic aberration. Therefore, by forming the condensing collimating means with the (aspherical) reflecting mirrors 10A and 10B, the occurrence of chromatic aberration is eliminated, and a wide wavelength band is supported.

  The heating laser light source 21 emits a heating laser having a heating laser wavelength (λa) adjusted to an output capable of heating without destroying the measurement object based on a control signal from the control means 50. To do. For example, the heating laser light source 21 is a semiconductor laser light source that emits a blue laser with λ = about 450 [nm]. The heating laser collimating means 41 is disposed in the vicinity of the heating laser light source 21 (near the laser emission position and on the optical axis of the heating laser), and the heating laser light emitted from the heating laser light source 21 is transmitted. Conversion to parallel laser heating laser La. For example, the heating laser collimating means 41 may be a collimating lens because it only needs to convert the light of the heating laser wavelength (λa) into parallel light. If the heating laser light source 21 can emit a parallel heating laser, the heating laser collimating means 41 can be omitted.

  The selective reflection means for heating laser 11A is arranged on the optical axis of the condensing collimating means 10, and outputs a heating laser La having a heating laser wavelength (λa) emitted from the heating laser light source 21 and converted into parallel light. Reflected toward one side of the condensing collimating means 10 and parallel to a wavelength different from the heating laser wavelength (λa) emitted and reflected from the measurement spot SP and emitted from one side of the condensing collimating means 10. The second measurement light L12 that is light is transmitted. For example, the selective reflection means for heating laser 11A is a dichroic mirror that reflects light having a heating laser wavelength (λa) and transmits light having a wavelength other than the heating laser wavelength (λa). Note that the measurement light which is parallel light emitted and reflected from the measurement spot SP and emitted from one side of the condensing collimating means 10 is referred to as first measurement light L11, and the light having the heating laser wavelength from the first measurement light L11. The remaining measurement light from which is taken out is referred to as second measurement light L12. The heating laser collimating means 41 and the heating laser selective reflection means 11A constitute a heating laser light guiding means. The heating laser light guiding means is a heating laser emitted from the heating laser light source 21. Is converted into parallel light and guided to one side of the condensing collimating means 10.

  The infrared detection means 31 can detect the energy of infrared rays (heat rays) emitted from the measurement spot SP. For example, the infrared detection means 31 is an infrared sensor. The detection signal from the infrared detecting means 31 is taken into the control means 50. The infrared selective reflection means 12B is a second measurement light L12 (having a wavelength different from the heating laser wavelength) that is parallel light that has been emitted from one side of the condensing collimating means 10 and transmitted through the heating laser selective reflection means 11A. (In this case, it is arranged on the optical axis of the condensing collimating means 10). Then, the infrared selective reflection means 12B has a predetermined infrared wavelength (λ1) out of the second measurement light L12 which is parallel light emitted from one side of the condensing collimating means 10 and transmitted through the heating laser selective reflection means 11A. ) Of infrared parallel light L1 is transmitted toward the infrared detection means 31, and the third measurement light L13, which is parallel light having a wavelength different from the predetermined infrared wavelength (λ1), is reflected.

  Accordingly, the infrared detecting means 31 detects only infrared energy having a predetermined infrared wavelength (λ1). For example, the infrared selective reflection means 12B is a dichroic mirror that transmits light having a predetermined infrared wavelength (λ1) and reflects light having a wavelength other than the predetermined infrared wavelength (λ1). The infrared condensing means 51 is disposed in the vicinity of the infrared detecting means 31 (near the detection position), and the infrared rays of the parallel light L1 having a predetermined infrared wavelength (λ1) transmitted by the infrared selective reflection means 12B are Light is condensed toward the infrared detecting means 31. For example, the infrared condensing means 51 may be a condensing lens because it only needs to condense light having a predetermined infrared wavelength (λ1). The selective reflection means for heating laser 11A, the selective reflection means for infrared rays 12B, and the infrared condensing means 51 constitute a radiating infrared light guiding means (corresponding to the infrared light guiding means). Infrared light having a predetermined infrared wavelength (λ1) is guided from the second measurement light L12, which is parallel light emitted from the measurement spot SP and emitted from one side of the condensing collimating means 10, to the infrared detecting means 31.

  The correction laser light source 71 emits a correction laser having a correction laser wavelength (λb) adjusted to an output sufficiently smaller than that of the heating laser based on a control signal from the control means 50. For example, the correction laser light source 71 is a semiconductor laser. Further, the output of the correction laser light source 71 is adjusted so that the temperature at which the measurement spot SP is heated by the correction laser does not affect the temperature at which the measurement spot is heated by the heating laser. The correction laser wavelength (λb) is a wavelength different from the heating laser wavelength (λa).

  The correction laser collimating means 81 is arranged in the vicinity of the correction laser light source 71 (near the laser emission position and on the optical axis of the correction laser), and corrects the correction laser emitted from the correction laser light source 71. Conversion to parallel light correction laser Lb is performed. For example, the correction laser collimating means 81 may be a collimating lens because it only needs to convert light of the correction laser wavelength (λb) into parallel light. If the correction laser light source 71 can emit a correction laser for parallel light, the correction laser collimating means 81 can be omitted.

  The beam splitter 17A reflects the light of the correction laser wavelength (λb) emitted from the correction laser light source 71 (correction laser) at the first predetermined ratio, transmits the light at the second predetermined ratio, and reflects the first predetermined ratio that is reflected. The parallel light correction laser is guided to the infrared selective reflection means 12B so as to overlap the third measurement light L13 which is parallel light having a wavelength different from the predetermined infrared wavelength. Note that the second predetermined ratio of the correction laser emitted from the correction laser light source 71 and transmitted through the beam splitter 17A is not used anywhere and is discarded. The correction laser light guiding means is constituted by the correction laser collimating means 81, the beam splitter 17A, the infrared selective reflection means 12B, and the heating laser selective reflection means 11A. The correction laser emitted from the laser light source 71 is converted into parallel light and guided to one side of the condensing collimating means 10 (that is, the measurement spot SP).

  The correction laser detection means 71R can detect the energy of the correction laser reflected by the measurement spot SP. For example, the correction laser detection means 71R can detect the energy of the light having the correction laser wavelength (λb). It is an optical sensor. The detection signal from the correction laser detection means 71R is taken into the control means 50. The beam splitter 17A transmits the (reflection) correction laser reflected from the measurement spot SP and reflected by the infrared selective reflection unit 12B toward the correction laser detection unit 71R at a second predetermined ratio.

  The reflected laser condensing means 81R is disposed in the vicinity of the correction laser detection means 71R (in the vicinity of the detection position), and is reflected from the measurement spot SP so as to go in a direction different from the correction laser light source 71 from the beam splitter 17A. The transmitted parallel light Lbr ((reflection) correction laser) of the correction laser wavelength (λb) is condensed toward the correction laser detection means 71R. The (reflection) correction laser reflected by the measurement spot SP and reflected by the beam splitter 17A is not used anywhere and is discarded. For example, the reflection laser condensing unit 81R may be a condensing lens because it only needs to condense light of the correction laser wavelength (λb). The heating laser selective reflection means 11A, the infrared selective reflection means 12B, the beam splitter 17A, and the reflection laser condensing means 81R constitute a reflection laser light guiding means, and the reflection laser light guiding means is the measurement spot SP. Then, the correction laser included in the first measurement light L11 reflected from and emitted from one side of the condensing collimating means 10 is guided to the correction laser detecting means 71R.

  As shown in “another example” surrounded by a dotted line in FIG. 4, the correction laser light source 71 and the correction laser collimating means 81 are replaced with the correction laser detection means 71 </ b> R and the reflected laser focusing means 81 </ b> R. May be. In this case, the beam splitter 17B transmits the light (correction laser) having the correction laser wavelength (λb) emitted from the correction laser light source 71 at the first predetermined ratio, and reflects and transmits the light at the second predetermined ratio. 1. A laser beam Lb for correcting a predetermined proportion of parallel light is guided to the infrared selective reflection means 12B so as to overlap the third measurement light L13 which is parallel light having a wavelength different from the predetermined infrared wavelength. The beam splitter 17B reflects the (reflection) correction laser reflected from the measurement spot SP and reflected by the infrared selective reflection unit 12B toward the correction laser detection unit 71R at a second predetermined ratio.

  The control means 50 is a personal computer or the like, controls the heating laser light source 21 and the correction laser light source 71, and determines the heating time based on the detection signal from the infrared detection means 31 and the detection signal from the correction laser detection means 71R. The temperature rise characteristic which is the temperature rise state of the measurement spot SP according to the above is measured. And the control means 50 determines the press-contact state of a measuring object based on the measured temperature rise characteristic. The temperature measurement method will be described later. Details of the operation of the control means 50 will be described later.

  The storage unit 60 is, for example, a storage device such as a hard disk. The storage unit 60 stores different temperature rise characteristics and the like depending on the pressure contact state of the measurement object to be determined. For example, the normalized upper limit temperature rise characteristic, normalized ideal temperature rise characteristic, normalized lower limit temperature rise characteristic, normalized saturation temperature, first reference threshold value, ideal reference threshold value, second reference threshold value, etc. shown in FIG. 14 are stored. Yes. The storage means 60 also stores the reflectance characteristics shown in FIG. 9, the infrared radiation characteristics shown in FIG.

  Then, the control means 50 measures the temperature rise characteristic using the optical nondestructive inspection apparatus 1A, and the saturation temperature at which the slope, which is the temperature change with respect to the time change from the heating start time in the measured temperature rise characteristic, is equal to or less than the predetermined slope. When the time to reach is not within the preset first reference threshold and second reference threshold (the first reference threshold and the second reference threshold are also stored in the storage unit 60), It is a defective product in which the contact area at the pressure contact portion of the object to be measured is out of the range of the desired size, or the contact pressure at the pressure contact portion is out of the desired pressure range. judge. Details of the operation of the control means 50 will be described later.

[Configuration of optical nondestructive inspection apparatus 1B in the second embodiment (FIG. 5)]
Next, the configuration of the optical nondestructive inspection apparatus 1B according to the second embodiment will be described with reference to FIG. The optical nondestructive inspection apparatus 1B of the second embodiment is different from the optical nondestructive inspection apparatus 1A of the first embodiment in the operation of the infrared selective reflection means 12A, the infrared detection means 31, and the correction use. The arrangement of the laser light source 71 and the correction laser detecting means 71R is different. Hereinafter, differences from the optical nondestructive inspection apparatus 1A according to the first embodiment will be mainly described.

  The infrared selective reflection means 12A is a second measurement light L12 (having a wavelength different from the heating laser wavelength) that is parallel light emitted from one side of the condensing collimating means 10 and transmitted through the selective reflection means 11A for heating laser. It is the same as the selective reflection means 12B for infrared rays in that it is arranged on the path of parallel light (in this case, it is arranged on the optical axis of the condensing collimating means 10). However, the selective reflection means for infrared rays 12A has a predetermined infrared wavelength (from the second measurement light L12 which is parallel light emitted from one side of the condensing collimating means 10 and transmitted through the selective reflection means for heating laser 11A ( The infrared parallel light L1 of λ1) is reflected toward the infrared detection means 31 (transmitted by the infrared selective reflection means 12B), and the third measurement light L13 which is parallel light having a wavelength different from the predetermined infrared wavelength (λ1) is reflected. It differs in that it is transmitted (reflected by the selective reflection means for infrared rays 12B). For example, the infrared selective reflection means 12A is a dichroic mirror that reflects light having a predetermined infrared wavelength (λ1) and transmits light having a wavelength other than the predetermined infrared wavelength (λ1).

  For this reason, the infrared condensing means 51 and the infrared detecting means 31 are arranged at the reflection destination of the infrared selective reflection means 12A, and the beam splitter 17A, the correction laser collimating means 81 and the transmission destination of the infrared selective reflection means 12A A correction laser light source 71, a reflected laser focusing means 81R, and a correction laser detection means 71R are arranged. Further, the correction laser emitted from the correction laser light source 71 is directed from the beam splitter 17A to the infrared selective reflection means 12A so as to overlap the third measurement light L13 which is parallel light having a wavelength different from the predetermined infrared wavelength. Then, the light is guided through the infrared selective reflection means 12A and guided to the heating laser selective reflection means 11A. The (reflection) correction laser reflected from the measurement spot SP passes through the infrared selective reflection means 12A and is guided to the beam splitter 17A.

  As shown in “another example” surrounded by a dotted line in FIG. 5, the correction laser light source 71 and the correction laser collimating means 81 are replaced with the correction laser detection means 71 </ b> R and the reflected laser focusing means 81 </ b> R. May be. In this case, the beam splitter 17B transmits the light (correction laser) having the correction laser wavelength (λb) emitted from the correction laser light source 71 at the first predetermined ratio, and reflects and transmits the light at the second predetermined ratio. 1 A parallel correction laser of a predetermined ratio is guided to the infrared selective reflection means 12A so as to overlap the third measurement light L13 which is parallel light having a wavelength different from the predetermined infrared wavelength. The beam splitter 17B reflects the (reflection) correction laser reflected from the measurement spot SP and transmitted through the infrared selective reflection means 12A toward the correction laser detection means 71R at a second predetermined ratio.

[Configuration of optical nondestructive inspection apparatus 1C according to the third embodiment (FIG. 6)]
Next, the configuration of the optical nondestructive inspection apparatus 1C according to the third embodiment will be described with reference to FIG. The optical nondestructive inspection apparatus 1C according to the third embodiment is different from the optical nondestructive inspection apparatus 1A according to the first embodiment in the operation of the selective reflection means 11B for heating laser. The arrangement is different. Hereinafter, differences from the optical nondestructive inspection apparatus 1A according to the first embodiment will be mainly described.

  The selective reflection means for heating laser 11B is disposed on the optical axis of the condensing collimating means 10 and emits a heating laser La having a heating laser wavelength (λa) emitted from the heating laser light source 21 and converted into parallel light. Heat that is transmitted toward one side of the condensing collimating means 10 (reflected by the selective reflection means 11A for heating laser) and emitted from one side of the condensing collimating means 10 after being emitted and reflected from the measurement spot SP The second measurement light L12, which is parallel light having a wavelength different from the laser wavelength (λa), is reflected (transmitted by the selective reflection means for heating laser 11A). For example, the selective reflection means for heating laser 11B is a dichroic mirror that transmits light having a heating laser wavelength (λa) and reflects light having a wavelength other than the heating laser wavelength (λa). The tip of the second measurement light L12, which is parallel light having a wavelength other than the heating laser wavelength (λa) reflected by the heating laser selective reflection means 11B, is the same as that in the first embodiment, and thus the description thereof is omitted. To do.

  As shown in “another example” surrounded by a dotted line in FIG. 6, the correction laser light source 71 and the correction laser collimating means 81, the correction laser detecting means 71 </ b> R, and the reflected laser focusing means 81 </ b> R are interchanged. May be. In this case, the beam splitter 17B transmits the light (correction laser) having the correction laser wavelength (λb) emitted from the correction laser light source 71 at the first predetermined ratio, and reflects and transmits the light at the second predetermined ratio. 1 A parallel correction laser for a predetermined ratio is guided to the infrared selective reflection means 12B so as to overlap the third measurement light L13 which is parallel light having a wavelength different from the predetermined infrared wavelength. The beam splitter 17B reflects the (reflection) correction laser reflected from the measurement spot SP and reflected by the infrared selective reflection unit 12B toward the correction laser detection unit 71R at a second predetermined ratio.

[Configuration of optical nondestructive inspection apparatus 1D according to the fourth embodiment (FIG. 7)]
Next, the configuration of the optical nondestructive inspection apparatus 1D according to the fourth embodiment will be described with reference to FIG. The optical nondestructive inspection apparatus 1D of the fourth embodiment differs from the optical nondestructive inspection apparatus 1B of the second embodiment in the operation of the heating laser selective reflection means 11B, and the heating laser light source 21 The arrangement is different. Hereinafter, differences from the optical nondestructive inspection apparatus 1B according to the second embodiment will be mainly described.

  The heating laser selective reflection means 11B is arranged on the optical axis of the condensing collimating means 10 and is emitted from the heating laser light source 21 and converted into parallel light, as in the third embodiment. The heating laser La having the wavelength (λa) is transmitted toward one side of the condensing collimating means 10 (reflected by the selective reflecting means 11A for heating laser) and is emitted and reflected from the measurement spot SP to collect the collimating means. The second measurement light L12 that is parallel light having a wavelength different from the heating laser wavelength (λa) emitted from one side of the laser beam 10 is reflected (transmitted by the heating laser selective reflection means 11A). For example, the selective reflection means for heating laser 11B is a dichroic mirror that transmits light having a heating laser wavelength (λa) and reflects light having a wavelength other than the heating laser wavelength (λa). The tip of the second measurement light L12 reflected by the selective reflection means for heating laser 11B, which is parallel light having a wavelength other than the heating laser wavelength (λa), is the same as that in the second embodiment, and thus the description thereof is omitted. To do.

  As shown in “another example” surrounded by a dotted line in FIG. 7, the correction laser light source 71 and the correction laser collimating means 81 are replaced with the correction laser detection means 71 </ b> R and the reflected laser focusing means 81 </ b> R. May be. In this case, the beam splitter 17B transmits the light (correction laser) having the correction laser wavelength (λb) emitted from the correction laser light source 71 at the first predetermined ratio, and reflects and transmits the light at the second predetermined ratio. 1 A parallel correction laser of a predetermined ratio is guided to the infrared selective reflection means 12A so as to overlap the third measurement light L13 which is parallel light having a wavelength different from the predetermined infrared wavelength. The beam splitter 17B reflects the (reflection) correction laser reflected from the measurement spot SP and transmitted through the infrared selective reflection means 12A toward the correction laser detection means 71R at a second predetermined ratio.

● [Optical nondestructive inspection procedure (Part 1) (Fig. 8)]
Next, an example of the processing procedure (part 1) of the control means 50 will be described using the flowchart shown in FIG. The configuration of the optical nondestructive inspection apparatus may be any of the first to fourth embodiments. The processing shown in FIG. 8 is executed by the control means 50 when the pressure contact state between the inner wall 91B and the elastic deformation portion 92B is inspected. Hereinafter, details of each process of the flowchart shown in FIG. 8 will be described in order.

  In step S10, the control means 50 controls the correction laser light source, emits the correction laser from the correction laser light source, and proceeds to step S15. The correction laser is guided to the measurement spot, and the correction laser reflected by the measurement spot is guided to the correction laser detection means.

  In step S15, the control means 50 controls the heating laser light source, emits the heating laser from the heating laser light source, and proceeds to step S20. The heating laser is guided to the measurement spot, and the infrared rays emitted from the measurement spot are guided to the infrared detection means. Note that the output of the heating laser is adjusted in advance so that the amount of heat to be heated without breaking the workpiece is obtained. In step S15, the heating laser light source is controlled from the control means, and the measurement is performed by irradiating the heating laser adjusted to the amount of heat to be heated without destroying the workpiece toward the measurement spot set on the measurement object. This corresponds to a heating step of heating the spot.

  In step S20, the control means 50 detects the infrared energy of the predetermined infrared wavelength (λ1) based on the detection signal from the infrared detection means, the detected infrared energy of the predetermined infrared wavelength (λ1), and the step The time from the start of the irradiation of the heating laser in S15 is captured and temporarily stored, and the process proceeds to step S25.

  In step S25, the control means 50 measures the reflectance of the correction laser based on the detection signal from the correction laser detection means, and proceeds to step S30. The procedure for obtaining the reflectance will be described later.

  In step S30, the control means 50 calculates the emissivity from the reflectance obtained in step S25, and proceeds to step S35. Specifically, the emissivity is calculated from the relationship of emissivity (%) = absorption rate (%) = 100 (%) − reflectance (%).

  In step S35, the control means 50 corrects the infrared energy temporarily stored in step S20 (corresponding to the detected value) based on the emissivity calculated in step S30, and calculates the measurement spot corresponding to the heating time. The temperature (corrected temperature) is obtained, and the process proceeds to step S40. A procedure for obtaining the temperature of the measurement spot (corrected temperature) will be described later.

  In step S40, the control means 50 determines whether it is the measurement end timing. When it is determined that the calculated temperature (corrected temperature) has reached the saturation temperature, the control unit 50 determines that it is the measurement end timing. For example, the control means 50 determines that the temperature has reached the saturation temperature when the temperature obtained in the current step S35 is in a temperature rising state below a predetermined value with respect to the temperature obtained in the previous step S35. . Note that the saturation temperature is a temperature in a thermal equilibrium state in which the temperature rise characteristic shown in FIG. If the control means 50 reaches the saturation temperature (becomes a thermal equilibrium state) and determines that the measurement end timing is reached (Yes), the control means 50 proceeds to step S45, and if it is determined not to be the measurement end timing (No), the control means 50 proceeds to step S20. Return. When returning to step S20, it is more preferable to return after waiting for a predetermined time (for example, about 1 ms) because the temperature can be obtained at predetermined time intervals. In steps S20 to S40, the control means detects the infrared rays (heat rays) radiated from the measurement spot using the infrared detection means while heating by the heating step, and the temperature of the measurement spot is detected. This corresponds to a temperature rise characteristic acquisition step for obtaining a temperature rise characteristic that is a temperature rise state of the measurement spot according to the heating time. The procedure for obtaining the reflectance in step S25, the procedure for obtaining the temperature of the measurement spot (corrected temperature) in step S35, and the procedure for obtaining the temperature rise characteristic will be described later. When the process proceeds to step S45, the control means 50 controls the heating laser light source, stops the irradiation of the heating laser, and proceeds to step S50. In step S50, the control unit 50 controls the correction laser light source to stop the irradiation of the correction laser, and proceeds to step S55.

  In step S55, the control means 50 determines that the temperature obtained in steps S20 to S40 and the temperature rise characteristic due to the heating time (FIG. 11) from the heating start point to the saturation temperature (the inclination that is the temperature change with respect to the time change is equal to or less than the predetermined inclination. The time until the temperature reaches a predetermined temperature) is determined, and the quality of the pressure contact state in the pressure contact portion is determined, and the process proceeds to step S60. In step S55, whether or not the pressure contact state including the contact area and the contact pressure at the pressure contact portion of the two workpieces is determined by the control unit based on the temperature rise characteristic of the measurement spot that is the heating point affected by the heat conduction amount. This corresponds to a determination step of determining. The procedure for determining whether or not the pressure contact state is good in step S55 will be described later.

  In step S60, the control unit 50 displays information on the result of the determination step (step S55) on the display unit and ends the process. The display means displays a screen based on an output signal from the control means, and is a monitor, for example. An example of screen display will be described later.

[Procedure for obtaining reflectance in step S25 (FIG. 9)]
For example, FIG. 9 shows an example of reflectance characteristics indicating the relationship between the wavelength of light (horizontal axis) and the reflectance (vertical axis) of substance A, substance B, and substance C set to a predetermined surface state. . As shown in FIG. 9, the reflectance varies depending on the material of the object and the wavelength of the light to be irradiated, and also varies depending on the surface state of the object (such as the density and depth of fine irregularities). Therefore, it is necessary to obtain the reflectance for each measurement spot. The control means 50 includes the energy of the correction laser from the correction laser light source, the reflectance of the beam splitter (first predetermined ratio (or second predetermined ratio)), and the transmittance of the beam splitter (second predetermined ratio (or second predetermined ratio (or second predetermined ratio)). 1 predetermined ratio)), and the reflectance of the measurement spot is measured based on the energy of the light of the correction laser wavelength detected by the correction laser detection means.

[Procedure for obtaining temperature of measurement spot in step S35 and procedure for obtaining temperature rise characteristics (FIGS. 10 to 11)]
For example, FIG. 10 shows the wavelength (horizontal axis) of infrared rays emitted from a black body when the temperature of the black body that completely absorbs and emits irradiated light is each temperature (M1, M2,... M6). The example of the infrared radiation characteristic which shows the relationship of the energy (vertical axis | shaft) of the infrared rays of each wavelength is shown. For example, when the measurement spot is a black body, the position of the detected predetermined infrared wavelength (λ1) is the position of (λ1) shown in FIG. 10, and the detected infrared energy is E1, the measurement spot It can be seen that the temperature of is M4 [° C.]. However, the actual measurement spot is not a black body, and a part of it is reflected without absorbing all of the irradiated heating laser, so correction is necessary, and the radiation obtained in the subsequent steps S25 to S30 is required. Based on the rate, the infrared energy detected in step S20 is corrected.

  For example, when the infrared energy temporarily stored in step S20 is E1 shown in FIG. 10, it is assumed that the result of correcting E1 using the emissivity obtained in step S30 is E1h. In this case, the temperature of the measurement spot is not M4 [° C.] (actual temperature) corresponding to E1, but M2 [° C.] (correction temperature) corresponding to the corrected E1h is the correct temperature. The infrared radiation characteristic shown in the example of FIG. 10 is stored in advance in the storage unit 60, and the control unit 50 detects the infrared radiation characteristic stored in the storage unit and the detected and corrected infrared energy (in this case, Based on the energy E1h), the temperature of the measurement spot (in this case, M2 [° C.]) is obtained.

  And a control means calculates | requires the temperature rise characteristic shown in the example of FIG. 11 from the time (equivalent to a heating time) after the irradiation start memorize | stored in step S20, and the correction temperature corresponding to the said time. For example, the time after the start of irradiation is T1, the actual temperature (temperature by the actually measured infrared energy (E1)) is M4 [° C.], and the corrected temperature (temperature by the corrected infrared energy (E1h)) is M2 [° C. ], And the time after the start of irradiation is T2, the actual temperature (temperature by the actually measured infrared energy (E2)) is M3 [° C.], the corrected temperature (corrected infrared energy (E2h)) FIG. 11 shows the case where the temperature of (1) is M1 [° C.]. Note that the temperature rise characteristic according to the correction temperature may be obtained by the control means, and the temperature rise characteristic due to the actual temperature need not be particularly obtained. In this way, the control means obtains the reflectance of the measurement spot (emissivity) and corrects the temperature of the measurement spot to obtain the correct temperature of the measurement spot, and the time after the start of irradiation (corresponding to the heating time) The temperature rise characteristic shown in the example of FIG. 11 is obtained from the temperature corresponding to the time.

  In this way, the control means controls the correction laser light source to irradiate the measurement spot with the correction laser having a predetermined output when obtaining the temperature of the measurement spot in the temperature rise characteristic acquisition step (steps S20 to S40). By detecting the correction laser that is the correction laser reflected at the measurement spot with the correction laser detection means, the characteristic (in this case, emissivity) regarding the reflectance at the measurement spot is obtained, and the infrared detection means The temperature of the measurement spot obtained based on the infrared of the predetermined wavelength detected in this way is corrected based on the characteristic relating to the reflectance.

[Procedure for determining pass / fail state of pressure contact in step S55 (FIGS. 12-14)]
We have already explained that the saturation temperature differs because the amount of heat conduction changes due to the difference in the contact area size and the contact pressure at the pressure contact part, but the saturation temperature is different for each measurement object. It is not preferable to determine whether the pressure contact state is good or bad. Therefore, as described below, the difference in saturation temperature is eliminated by normalizing the measured temperature rise characteristics so that the saturation temperature for each measurement object is the same.

  In step S55, the control means 50 compresses in the temperature direction so that the saturation temperature in the temperature rise characteristic (FIG. 11) obtained by the temperature obtained in steps S20 to S40 and the heating time becomes a preset normalized saturation temperature. Alternatively, the normalized temperature rise characteristic is obtained by processing so as to extend (the time axis direction is not particularly processed). For example, the normalized saturation temperature is set to the saturation temperature in the temperature rise characteristic of the measurement object in which the size of the contact area at the pressure contact portion is an ideal size and the size of the contact pressure is an ideal size. The normalized saturation temperature is set and stored in the storage means 60. Then, when the saturation temperature of the measured temperature rise characteristic is higher than the normalized saturation temperature, the control means 50 makes the measured saturation temperature of the temperature rise characteristic coincide with the normalized saturation temperature as shown in FIG. In addition, the normalized temperature rise characteristic can be obtained by compressing the temperature rise characteristic in the temperature direction. In addition, when the saturation temperature of the measured temperature rise characteristic is lower than the normalized saturation temperature, the control means 50 makes the measured saturation temperature of the temperature rise characteristic coincide with the normalized saturation temperature as shown in FIG. In addition, the normalized temperature rise characteristic can be obtained by extending the temperature rise characteristic in the temperature direction.

  FIG. 14 shows a normalized value obtained by normalizing the temperature rise characteristics of an object to be measured in which the size of the contact area of the pressure contact portion is an ideal size and the size of the contact pressure of the pressure contact portion is an ideal size. The ideal temperature rise characteristic (indicated by a dotted line in FIG. 14) and the temperature rise characteristic of a measurement object in which the size of the contact area of the pressure contact portion is the allowable lower limit and the size of the contact pressure of the pressure contact portion is the allowable lower limit. The normalized lower limit temperature rise characteristic (indicated by a one-dot chain line in FIG. 14), the size of the contact area of the pressure contact portion is the allowable upper limit, and the size of the contact pressure of the pressure contact portion is the allowable upper limit. An example is shown in which a normalized upper limit temperature rise characteristic (indicated by a two-dot chain line in FIG. 14) obtained by normalizing the temperature rise characteristic of the measurement object is displayed. In this way, by normalizing the saturation temperature to the normalized saturation temperature, the difference in the contact area and the difference in the contact pressure in the pressure contact portion is normalized and saturated from the start of heating (time). It can be represented by a graph until the temperature is reached.

  When the result of normalizing the temperature rise characteristic of the measurement object does not fall between the normalized upper limit temperature rise characteristic and the normalized lower limit temperature rise characteristic shown in FIG. 14, the contact at the pressure contact portion of the measurement object It can be said that the area is out of the desired range, or the contact pressure at the pressure contact portion is out of the desired range. That is, when the result of normalizing the temperature rise characteristic of the measurement object is within the normalized upper limit temperature rise characteristic and the normalized lower limit temperature rise characteristic shown in FIG. 14, the pressure contact portion of the measurement object It can be said that the contact area is within the desired range, and the contact pressure at the pressure contact portion is within the desired range.

  It should be noted that the normalization saturation is determined from the heating start time point to determine whether the result of normalizing the obtained temperature rise characteristic is between the normalized upper limit temperature rise characteristic and the normalized lower limit temperature rise characteristic shown in FIG. The time to reach the temperature is the first reference threshold (the time from the start of heating to the normalized saturation temperature in the normalized upper limit temperature rise characteristic) and the second reference threshold (from the start of heating in the normalized lower limit temperature rise characteristic). Or the time until the normalized saturation temperature is reached). In this case, in step S35, the control means starts from the time of starting the irradiation of the heating laser to the measurement spot until the temperature rise characteristic reaches a thermal equilibrium state where the temperature rise state with respect to time elapses below a predetermined rise state. When the time does not fall between the first reference threshold value and the second reference threshold value set in advance, the contact area is out of the desired size range or the contact pressure is desired. It is determined that it is a defective product that is out of the range of pressure (ie, it is determined to be a non-defective product if it is between the first reference threshold value and the second reference threshold value). Note that the normalized saturation temperature, the first reference threshold value, and the second reference threshold value are stored in advance in the storage unit.

  In the above description, the first reference threshold is set as the time from the start of heating to the normalized saturation temperature in the normalized upper limit temperature rise characteristic, and the second reference threshold is set from the start of heating in the normalized lower limit temperature rise characteristic. The time required to reach the normalized saturation temperature was used. However, the first reference threshold is the time from the start of heating in the normalized upper limit temperature rise characteristic until it reaches 90% of the normalized saturation temperature, and the second reference threshold is normalized from the start of heating in the normalized lower limit temperature rise characteristic. The time to reach 90% of the saturation temperature, and the time to reach 90% of the normalized saturation temperature in the result of normalizing the obtained temperature rise characteristic is between the first reference threshold and the second reference threshold. You may make it determine with it being non-defective if it is settled. In addition, the determination method of the quality of a press-contact state is not limited to the method demonstrated above. For example, when the saturation temperature in the obtained temperature rise characteristic is within a predetermined temperature range, it is determined that the product is non-defective, or the time until the saturation temperature is reached is normalized without normalizing the obtained temperature rise characteristic. An area enclosed by a graph of normalized temperature rise characteristics obtained by normalizing the obtained temperature rise characteristics within a predetermined range is determined to be a non-defective product when it falls between the first reference threshold and the second reference threshold. In some cases, it may be determined that the product is non-defective.

[Example of information on determination result displayed on display means in step S60 (FIG. 15)]
Next, an example of display in step S60 is shown in FIG. The example shown in FIG. 15 shows an example in which information related to the determination result of the control means is displayed on the screen 50M of the display means 50G of the control means 50. In this example, the determination result is “good”, and shows a case where it is determined that the contact area and the contact pressure in the press contact portion are within the desired ranges. In the example of FIG. 15, the normalized temperature rise characteristic of the measurement object (indicated by a solid line in the screen 50M) and the normalized lower limit temperature rise characteristic (indicated by a one-dot chain line in the screen 50M) And a normalized temperature rise characteristic graph (indicated by a two-dot chain line in the screen 50M) and a normalized ideal temperature rise characteristic (indicated by a dotted line in the screen 50M). The displayed example is shown. By just looking at this temperature rise characteristic graph, the operator can easily determine that the pressure contact state of the measurement object is within the allowable range, but is slightly shifted to the upper limit side, so quality control, etc. Is very useful when doing.

● [Welding method for welded parts joined by pressure welding without being welded]
In the above description, the quality of the pressure contact state of the pressure contact portion in which the elastic deformation portion 92B of the press-fit pin 92 is inserted into the inner wall 91B of the through hole 91 is determined. This welded portion is joined by pressure welding without being welded. However, if it is determined that the pressure welded state is a non-defective product as a result of the above determination, it is more reliable by welding as follows. The desired conductivity can be ensured. The welding step described below may be performed between step S55 and step S60 shown in FIG. 8, or may be omitted.

  First, as a precondition, at least one of the pressure contact portions of the two workpieces is plated with an alloy or metal having a melting point lower than the melting points of the conductive members of the pressure contact portions of the two workpieces (for example, solder plating or tin plating). Has been. For example, the inner wall 91B of the through hole 91 is solder plated. In the heating step, the heating laser light source is controlled from the control means, and the measurement spot is irradiated with a heating laser whose output is adjusted to a heat amount that is less than the melting point of the plating and is heated without destroying the workpiece. To do.

  And when it determines with a non-defective product in the determination step, the output of the laser light source for heating is adjusted by the control means to the amount of heat that heats the workpiece without destroying it and to the amount of heat that is equal to or higher than the melting point of the plating. After raising the laser to a new heating laser, the plating is melted by irradiating the measurement spot with a new heating laser for a predetermined time, and two workpieces are welded at the pressure contact portion. This step of welding is a welding step. In this way, after confirming that the two workpieces joined by pressure welding without being welded are in the desired pressure welding state, the pressure welding portion can be welded appropriately and easily. The desired conductivity can be ensured. Moreover, the plating shaving part, the fine whisker etc. by tin etc. can be fuse | melted, and it can be set as a more reliable press-contact state (electric conduction state). Moreover, the process of removing the plating scrap is not required. In the above description, the welding step is performed after the heating step. However, the heating step and the welding step can be performed simultaneously. In this case, in the heating step, the heating laser light source is controlled from the control means, and the heating laser with the output adjusted to the amount of heat that heats the workpiece without destroying it and exceeds the melting point of the plating is measured. Can be irradiated. Thereby, a test | inspection can be complete | finished in a short time rather than the case where a heating step and a welding step are performed separately.

● [Processing procedure of optical nondestructive inspection equipment (Part 2) (Fig. 16)]
Next, an example of a processing procedure (part 2) of the control means 50 will be described using the flowchart shown in FIG. The configuration of the optical nondestructive inspection apparatus may be any of the first to fourth embodiments. In the above-described processing procedure (part 1), the measured infrared energy was corrected based on the reflectance, and the temperature rise characteristics were obtained from the corrected temperature obtained from the corrected infrared energy and the time from the start of heating. In the processing procedure (part 2) described below, the output of the heating laser is adjusted (increased) based on the reflectance so that the measured infrared energy is equivalent to the above-described “corrected infrared energy”. Is.

  In step S110, the control means 50 controls the correction laser light source, emits the correction laser from the correction laser light source, and proceeds to step S115. The correction laser is guided to the measurement spot, and the correction laser reflected by the measurement spot is guided to the correction laser detection means.

  In step S115, the control means 50 measures the reflectance of the correction laser based on the detection signal from the correction laser detection means, and proceeds to step S120. The method for obtaining the reflectance is as described above.

  In step S120, the control means 50 calculates an absorptance from the reflectance obtained in step S115, and proceeds to step S125. Specifically, the absorptance is calculated from the relationship of absorptance (%) = 100 (%) − reflectance (%). In step S125, the control means 50 calculates the emissivity from the absorption rate obtained in step S120, and proceeds to step S130. Specifically, the emissivity is calculated from the relationship of absorption rate (%) = emissivity (%).

  In step S130, the control means 50 calculates an output value to be output from the heating laser light source based on the absorption rate (or emissivity) obtained in step S120, and proceeds to step S135. For example, if a heating laser is emitted with an output W1, if the infrared energy E1 in FIG. 10 is expected to be detected from the relationship of the absorptance, a heating laser whose detected infrared energy is E1h is assumed. The output W1h is calculated according to the absorption rate.

  In step S135, the control means 50 controls the heating laser light source, emits the heating laser with the output value obtained in step S130, and proceeds to step S140.

  In step S140, the control means 50 detects the infrared energy of the predetermined infrared wavelength (λ1) based on the detection signal from the infrared detection means, the detected infrared energy of the predetermined infrared wavelength (λ1), and the heating energy The time from the start of laser irradiation is captured and stored, and the process proceeds to step S145.

  In step S145, the control means 50 obtains the temperature (actual temperature) corresponding to the captured infrared energy, obtains the temperature rise characteristic from the obtained actual temperature and the time after the start of irradiation, and proceeds to step S150. In this case, since the output of the heating laser is adjusted (increased) according to the absorption rate, the obtained actual temperature (in this case, the actual temperature = the temperature after correction) may be used as it is as the temperature rise characteristic. Since the method for converting the detected infrared energy into temperature is as described above, the description thereof is omitted.

  In step S150, the control means 50 determines whether it is the measurement end timing. As described above, when it is determined that the calculated temperature has reached the saturation temperature, the control unit 50 determines that it is the measurement end timing. If the control means 50 has reached the saturation temperature and determines that it is the measurement end timing (Yes), the process proceeds to step S155, and if it is determined that it is not the measurement end timing (No), the control means 50 returns to step S115. When returning to step S115, it is more preferable to wait for a predetermined time (for example, about 1 ms) before returning, so that the actual temperature can be obtained at predetermined time intervals.

  When the process proceeds to step S155, the control unit 50 controls the heating laser light source to stop the irradiation of the heating laser, and the process proceeds to step S160. In step S160, the control unit 50 controls the correction laser light source, stops the irradiation of the correction laser, and proceeds to step S165.

  In step S165, the control means 50 determines the pressure contact state of the measurement object based on the temperature rise characteristic due to the actual temperature obtained in step S145, and displays the determination result on the display means or the like in step S170 for processing. Exit. In addition, since the determination method of the press-contact state of a measurement object and the display method to a display means are the same as the method mentioned above, description is abbreviate | omitted.

  As described above, the optical nondestructive inspection apparatus described in this embodiment uses the temperature rise characteristic of a period of about several tens of ms from the start of heating with the heating laser to the saturation temperature. Since the state is determined, the inspection time is very short. In addition, since it is possible to perform non-contact inspection for inspection of the pressure contact state of the pressure contact portion, it is not necessary to fix the vibrator or sensor of the ultrasonic oscillator in the vicinity of the pressure contact portion or the pressure contact portion. In addition, the inspection can be performed in a short time without trouble. In addition, by determining the heat conduction state, the pressure contact state between the conductive member (inner wall of the through hole) and the conductive member (elastically deformed portion of the press-fit pin) is determined, so the electrical conduction state is appropriately determined. Is possible. Therefore, as compared with the method of confirming the insertion position with an image, it is possible to appropriately inspect the electrical continuity state that should be inspected, and it is possible to inspect with higher reliability. In addition, even if the saturation temperature of each temperature rise characteristic varies, saturation is achieved by compressing or expanding the temperature rise characteristic in the temperature direction so as to obtain a preset normalized saturation temperature, thereby obtaining a normalized temperature rise characteristic. Since the temperature rise characteristics are normalized and determined so as to be unified with the normalized saturation temperature regardless of the difference in temperature, more accurate determination can be performed.

  Moreover, the temperature of a measurement spot can be calculated | required more correctly by calculating | requiring the reflectance (emissivity) of a measurement spot using a correction | amendment laser, and correct | amending the temperature of a measurement spot.

  It should be noted that the heating laser light source 21, the condensing collimating means 10, the heating laser light guiding means, the infrared detecting means, the infrared light guiding means, and the correction laser light source for performing the processing procedure described above. 71, a correction laser light guide means, a correction laser detection means 71R, a reflected laser light guide means, and a control means 50, so that the contact area at the pressure contact portion between two members that are measurement objects It is of course possible to configure an optical nondestructive inspection apparatus that determines whether or not the contact pressure is within the allowable range and whether or not the contact pressure is within the allowable range by the control means.

  The processing procedure, configuration, structure, appearance, shape, and the like of the optical nondestructive inspection method and optical nondestructive inspection apparatus of the present invention can be variously changed, added, and deleted without changing the gist of the present invention.

  The example of the reflectance characteristic (FIG. 9), the example of the infrared radiation characteristic (FIG. 10) described in the present embodiment, and the position of the predetermined infrared wavelength (λ1) shown in this infrared radiation characteristic is one. It is an example and is not limited to this. Further, the above (≧), the following (≦), the greater (>), the less (<), the expression that there is B between A and C (A <B <C), etc. are included even if they contain an equal sign. It does not have to be. The numerical values used in the description of the present embodiment are examples, and are not limited to these numerical values.

  In the description of the present embodiment, the press contact portion in which the elastic deformation portion of the press-fit pin is press-contacted to the inner wall of the through hole is described as an example, but the two works are not limited to these, and are conductive members. The present invention can be applied to pass / fail judgment of the press contact portions of the various two configured workpieces. Further, the type of plating is not limited to solder plating or tin plating, and various types of plating can be used.

1A, 1B, 1C, 1D Optical nondestructive inspection apparatus 10 Condensing collimating means 10A, 10B (Aspherical) reflecting mirror 11A, 11B Selective reflecting means for heating laser 12A, 12B Selective reflecting means for infrared rays 17A, 17B Beam splitter 21 Heating Laser light source 31 Infrared detection means (heat ray detection means)
41 Laser collimating means for heating 50 Control means 50G Display means 51 Infrared condensing means 60 Storage means 71 Laser light source for correction 71R Laser detecting means for correction 81 Laser collimating means for correction 81R Reflective laser condensing means 90 Substrate 91 Through hole 91A Land 91B Inner wall (pressure contact)
92 Press Fit Pin 92A Tip 92B Elastic Deformation (Pressure Contact)
92C Base portion L11 First measurement light L12 Second measurement light L13 Third measurement light SP Measurement spot

Claims (5)

Pressure welding portion of two workpieces joined by pressure welding without being welded, wherein the pressure welding portion in one workpiece and the pressure welding portion in the other workpiece are each composed of a conductive member. An optical nondestructive inspection method for determining a state,
A measurement spot is set on the surface of one of the workpieces in the vicinity of the pressure contact portion and the surface of the conductive member including the pressure contact portion,
A heating laser light source for emitting a heating laser having a predetermined laser wavelength;
Infrared detecting means capable of detecting infrared rays of a predetermined infrared wavelength;
A correction laser light source that emits a correction laser having a smaller correction laser wavelength than the heating laser; and
Correction laser detecting means capable of detecting the correction laser;
Using the control means for controlling the heating laser light source and the correction laser light source and taking in detection signals from the infrared detection means and the correction laser detection means,
The heating laser light source is controlled by controlling the heating laser light source from the control means, and the measuring spot is heated by irradiating the heating laser adjusted to an amount of heat to be heated without destroying the workpiece. Steps,
While performing the heating in the heating step, the control means detects infrared radiation emitted from the measurement spot using the infrared detection means to determine the temperature of the measurement spot, and determines the temperature of the measurement spot according to the heating time. A temperature rise characteristic obtaining step for obtaining a temperature rise characteristic in a temperature rise state;
Based on the temperature rise characteristic of the measurement spot, which is a heating point affected by the amount of heat conduction, the control means determines the quality of the pressure contact state including the contact area and the contact pressure at the pressure contact portion of the two workpieces. And a determination step.
In the temperature rise characteristic obtaining step, when the control means obtains the temperature of the measurement spot, the correction laser light source is controlled to irradiate the measurement spot with the correction laser having a predetermined output, and the measurement The correction laser detection means, which is the correction laser reflected at the spot, is detected by the correction laser detection means to obtain characteristics relating to the reflectance at the measurement spot, and the predetermined detection detected by the infrared detection means Correcting the temperature of the measurement spot determined based on the infrared rays of the wavelength based on the characteristics relating to the reflectance;
Optical nondestructive inspection method. The optical nondestructive inspection method according to claim 1,
At least one of the pressure contact portions of the two workpieces is plated with an alloy or metal having a melting point lower than the melting point of each of the conductive members of the pressure contact portions of the two workpieces,
In the heating step, the heating laser light source is controlled by controlling the heating laser light source from the control means so as to heat the workpiece without destroying the workpiece, and the output of the heating laser is adjusted to be less than the melting point of the plating. To the measurement spot,
When it is determined that the product is a non-defective product in the determination step, the output of the heating laser light source is adjusted by the control unit to a heat amount that heats the workpiece without destroying the workpiece and is equal to or higher than a melting point of the plating. After raising to a new heating laser that is an output, the plating is melted by irradiating the measurement spot with the new heating laser for a predetermined time, and the two workpieces are welded at the pressure contact portion, Welding step,
Optical nondestructive inspection method. The optical nondestructive inspection method according to claim 1,
At least one of the pressure contact portions of the two workpieces is plated with an alloy or metal having a melting point lower than the melting point of each of the conductive members of the pressure contact portions of the two workpieces,
In the heating step, the heating laser light source that controls the heating laser light source from the control means to heat the workpiece without destroying the workpiece and adjust the heat amount to be equal to or higher than the melting point of the plating is used. Irradiating the measurement spot,
Optical nondestructive inspection method. An optical nondestructive inspection method according to any one of claims 1 to 3,
In the determination step, the control means includes a thermal equilibrium state in which the temperature rise state with respect to the passage of time is equal to or less than a predetermined rise state in the temperature rise characteristic from the start of the irradiation of the heating laser to the measurement spot. The contact area is out of the range of the desired size when the time until is not within the preset first reference threshold and the second reference threshold, or It is determined that the contact pressure is a defective product outside the desired pressure range.
Optical nondestructive inspection method. An optical nondestructive inspection apparatus for executing the optical nondestructive inspection method according to any one of claims 1 to 4,
The heating laser light source;
Parallel light incident from one side along the optical axis is condensed toward the measurement spot set as a focal position and emitted from the other side, and the other side is radiated and reflected from the measurement spot. Condensing collimating means for converting light incident from one side into measurement light that is parallel light along the optical axis and emitting from one side;
A laser light guide for heating that converts the laser for heating into parallel light and guides it to one side of the condensing collimator;
The infrared detection means;
Infrared light guide means for guiding the infrared light of the predetermined infrared wavelength corresponding to the heat radiated from the measurement spot, which is the infrared light contained in the measurement light, to the infrared detection means,
The correction laser light source;
A correction laser light guide means for converting the correction laser into parallel light and superimposing at least a part of the correction laser converted into parallel light on the measurement light to the measurement spot;
The correction laser detection means;
Reflected laser light guide means for guiding at least a part of the reflection correction laser reflected by the measurement spot and included in the measurement light to the correction laser detection means;
The control means,
Optical nondestructive inspection device.

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