JP4159952B2 - Metal foreign object detection device and detection method - Google Patents

Description

  The present invention relates to an apparatus and a method for detecting metallic foreign matter mixed in powders of non-conductive materials such as electric and electronic materials such as magnetic oxides, ceramics and resins (plastics), food materials such as flour, and other industrial materials. About.

  Conventionally, an X-ray detection method, an electromagnetic induction detection method, or the like has been used to detect metallic foreign matters mixed in powders of industrial materials and foods. In the X-ray detection method, when a microfocus device is used, a metal foreign object having a size of about 0.1 mm can be detected, but the device is expensive. On the other hand, the electromagnetic induction detection method can detect a metal foreign object having a dimension of about 0.5 mm.

A conventional electromagnetic induction type metal foreign object detection device will be described with reference to FIG.
FIG. 9A shows an outline of a conventional electromagnetic induction type metal foreign object detection device, and FIG. 9B shows a configuration of a control unit. (For example, refer to Patent Document 1.)
Excitation coil (transmission coil) TC and detection coils (reception coil) RC1, RC2 are arranged to face each other. The excitation coil TC is excited by the excitation power supply 10. The inspection object 11 moves between the excitation coil TC and the detection coils RC1, RC2 by a conveyor or the like (not shown).
The detection coils RC <b> 1 and RC <b> 2 are connected in series with the winding direction being reversed and connected to the variable resistor 12. The detection coils RC1 and RC2 induce a signal when a metal foreign object is mixed in the inspection object 11. The signals are detected by the synchronous detectors 131 and 132, converted into digital signals by the A / D conversion circuits 141 and 142, and sent to the control unit 15 including a microcomputer or the like. The control unit 15 forms a Lissajous waveform, compares the Lissajous waveform with a reference Lissajous waveform, determines the presence / absence of metallic foreign matter, and generates a foreign matter detection signal when metallic foreign matter is mixed. The display device 16 displays that a metal foreign object has been detected.
The control unit 15 includes a digital signal acquisition unit 151, a Lissajous waveform forming unit 152, a reference Lissajous waveform storage unit 153, a Lissajous waveform comparison unit 154, a metal foreign object detection signal generation unit 155, and the like.

JP 2001-91662 A

  Conventional electromagnetic induction type foreign matter detection devices are arranged so that the exciting coil and the detection coil face each other, and are configured to induce a signal in the detection coil when metallic foreign matter is mixed in the object to be inspected. It is susceptible to noise and may generate a false detection signal. In the case of FIG. 10, if the signal output position of the variable resistor is not set correctly, the balance of the outputs of the two detection coils is lost and noise is generated. Further, in the Lissajous waveform, the mixed metal foreign matter is different between the magnetic body and the non-magnetic body, and is also different depending on the size of the metal foreign matter, so comparison of the Lissajous waveform is not easy.

  As electronic devices and electronic parts become smaller and more functional, electrical and electronic materials for producing them are required to have high purity, and the allowable dimensions of metallic foreign objects mixed in electrical and electronic materials are minimized. There is a tendency. For example, when a ceramic substrate mounted with a semiconductor element such as an IC is housed in a package and filled with resin, the size of the metal foreign matter in the ceramic or resin powder is small in order to prevent short-circuiting of finely spaced wiring and terminals. It must be smaller than the wiring interval and the terminal interval, and recently needs to be about 0.1 mm to 70 μm. Also, recent transformers with dimensions of about 1.2 x 1.4 mm or less are made by molding magnetic oxide, but allow for metal foreign matter in the magnetic oxide powder. The dimensions are about 0.1 mm to 70 μm as described above. However, the size of metal foreign matter that can be detected in powders of non-conductive materials such as ceramics, resins, and magnetic oxides is limited to about 0.1 mm by the X-ray detection method and about 0.5 mm by the electromagnetic induction detection method. It is.

  In view of the above problems, the present invention is not affected by noise unlike conventional electromagnetic induction type foreign matter detection devices, does not require the formation of a Lissajous waveform, and has a size smaller than that of conventional metal foreign matter detection devices. An object of the present invention is to provide a metal foreign object detection device and a detection method capable of detecting a metal foreign object.

In order to achieve the object of the present invention, the metallic foreign object detection device according to claim 1 comprises a high frequency magnetic flux generating coil, a yoke, and two magnetic poles. The yoke, the magnetic pole, the device under test, the magnetic pole, and the yoke a magnetizer for generating a high-frequency magnetic flux forms a magnetic path, and conveying the glass tube for holding the object to be tested of the molded body of non-conductive material powder between the magnetic poles of the magnetic path of the high frequency magnetic flux, its An infrared camera that measures the temperature distribution of the object to be inspected from the outside of the glass tube for conveyance is provided.
The metal foreign object detection device according to claim 2 is the metal foreign object detection device according to claim 1, wherein the non-conductive material powder is an electric / electronic material powder such as ceramics, resin, or magnetic oxide. Features.

According to a third aspect of the present invention, there is provided a metal foreign object detection method including a high-frequency magnetic flux generating coil, a yoke, and two magnetic poles, and using a magnetizer that forms a magnetic path of the yoke, the magnetic pole, the device under test, the magnetic pole, and the yoke. A conveyance glass tube is arranged between the magnetic poles of the path, and the metal foreign matter in the inspected object of the non-conductive material powder molded body held in the conveyance glass tube is induced and heated by the magnetic flux generated by the magnetizer. The temperature distribution of the object to be inspected is measured by an infrared camera from the outside of the conveying glass tube to detect the metal foreign matter.
The metal foreign matter detection method according to claim 4 is the metal foreign matter detection method according to claim 3, wherein the non-conductive material powder is an electric / electronic material powder such as ceramics, resin, magnetic oxide or the like. Features.

Unlike the conventional electromagnetic induction type metal foreign object detection device, the metal foreign object detection apparatus of the present invention is provided with a detection coil, and it is not necessary to take out a signal induced in the detection coil. 4 is used only for heating the metallic foreign matter, and the metallic foreign matter is detected by the temperature distribution measuring means of the infrared camera, so that the noise around the inspected object 4 does not affect the detection of the metallic foreign matter. That is, the metal foreign object detection device of the present invention is not affected by noise. The magnetizer of the present invention has a simple structure because it does not have a detection coil. The magnetizer coil and the temperature distribution measuring means of the infrared camera are not electrically coupled, so the positional relationship between the excitation coil and the detection coil needs to be adjusted as in the conventional electromagnetic induction type metal foreign object detection device. Therefore, the metal foreign object detection device can be easily handled. Further, the metal foreign object detection device of the present invention does not need to form a Lissajous waveform unlike the conventional electromagnetic induction type metal foreign object detection device.
The metal foreign object detection device of the present invention can also detect a metal foreign object of a minute size (about 50 μm) that could not be detected by a conventional electromagnetic induction type metal foreign object detection device or the like.
The magnetizer of the present invention can be set so that the magnetic flux flows back through the yoke, the magnetic pole, the device under test, the magnetic pole, and the magnetic path of the yoke, and the size of the tip of the magnetic pole is concentrated on the device under test .
In the present invention, the object to be inspected is held in the glass tube for conveyance, and the infrared camera is used for measuring the temperature distribution of the object to be inspected, so that the object to be inspected can be taken from outside the glass tube .
Since the object to be inspected of the present invention is a molded body, it can be inspected for each molded body, and a molded body in which metal foreign matter is mixed can be taken out as a defective product .

In the embodiment of the present invention, the metal foreign matter in the powder to-be-inspected object is detected by the induction heating means and the temperature measuring means such as the infrared camera and the radiation thermometer.
An embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is used for the part common to each figure.
FIG. 1 is a block diagram of a metal foreign object detection device according to an embodiment of the present invention.
In FIG. 1, 21 is an infrared camera, 3 is a conveyor, 4 is an object to be inspected of powder, M is a magnetizer, 22 is an imaging control circuit, 23 is a monitor, 24 is a foreign matter detection circuit, and 55 is a magnetization power supply circuit. . The magnetizer M includes a coil C, a yoke Y, and magnetic poles P1 and P2.

  The inspection object 4 is held by the conveyor 3 and moves together with the conveyor 3 between the magnetic pole P1 and the magnetic pole P2 in a direction perpendicular to the paper surface. The coil C is a heating coil (inductor), and generates a high-frequency magnetic flux when a high-frequency current (25 to 70 kHz) is supplied from the magnetization power supply circuit 55. The high-frequency magnetic flux flows back through the magnetic path of the yoke Y, the magnetic pole P1, the device under test 4, the magnetic pole P2, and the yoke Y. Since the object to be inspected 4 is held in the magnetic path, when a metal foreign object is mixed in the object to be inspected 4, an eddy current is induced in the metal foreign object and Joule heat is generated. That is, the metallic foreign matter mixed in the inspection object 4 generates heat by so-called dielectric heating. As a result, in the object 4 to be inspected, the portion where the metallic foreign matter is mixed locally becomes high temperature.

  The infrared camera 21 is controlled by the imaging control circuit 22 and captures infrared rays emitted from the inspection object 4 and converts them into electrical signals. The amount of infrared rays emitted from the inspection object 4 corresponds to the temperature of each part of the inspection object 4. Therefore, the output of the infrared camera 21 corresponds to the temperature distribution of the object 4 to be inspected, and increases in the portion where the metallic foreign object exists. The imaging control circuit 22 sends the imaging signal of the infrared camera 21 to the monitor 23 and the foreign object detection circuit 24. The monitor 23 displays the temperature distribution waveform or temperature distribution image of the inspection object 4 on the screen. From the temperature distribution waveform or the temperature distribution image, the temperature distribution of the inspection object 4 can be visually recognized, and the presence / absence of mixed metal foreign matter can be determined. Further, the foreign object detection circuit 24 compares the imaging signal (temperature distribution waveform) of the inspection object 4 with the imaging signal (temperature distribution waveform) of the inspection object that does not contain metallic foreign objects, and determines whether or not metallic foreign objects are mixed. When a foreign metal is mixed, a foreign object detection signal is generated.

Unlike the conventional electromagnetic induction type metal foreign object detection device, the metal foreign object detection device of the present embodiment is provided with a detection coil, and it is not necessary to detect a signal induced in the detection coil by electromagnetic induction. That is, the coil C is used only for heating the metal foreign matter mixed in the inspection object 4 and the detection of the metal foreign object is performed by the infrared camera 21, so that the noise around the inspection object 4 affects the detection of the metal foreign object. Never do. Therefore, the metal foreign object detection device of the present embodiment is not affected by noise. Further, since the coil C and the infrared camera 21 are not electrically coupled, there is no need to adjust the positional relationship between the excitation coil and the detection coil as in the conventional electromagnetic induction type metal foreign object detection device. The detection device can be handled easily. Further, the metal foreign object detection device of the present embodiment does not need to form a Lissajous waveform unlike the conventional electromagnetic induction type metal foreign object detection device.
Since the metal foreign object detection device of the present embodiment moves the object 4 to be inspected by the conveyor 3, it can continuously detect metal foreign objects.

  The measurement of the temperature distribution of the inspection object 4 is not limited to the infrared camera, and may be a radiation thermometer or the like. In addition, since the detection of the metal foreign object only needs to be able to determine the presence or absence of the metal foreign object mixed in the inspection object 4, the determination may be made by directly comparing the imaging signal (temperature distribution waveform) of the infrared camera 21. The image may be processed by a computer and a so-called thermography method may be used.

The metal foreign object detection device of the present embodiment can be applied to the detection of metal foreign objects mixed in non-conductive materials such as ceramics, resins (plastics), magnetic oxides, etc., especially electric and electronic material powders. It can also be applied to the detection of metallic foreign matter mixed in food materials, food powders, and industrial material powders. When the object 4 to be inspected is a magnetic oxide powder, an eddy current is also generated in the magnetic oxide, but the magnetic oxide has a high resistivity and a small eddy current, so that it does not hinder the detection of foreign metal.
The powder of the object to be inspected may be a powder itself, or a powder obtained by forming a powder described later into a pellet form. Therefore, the present application is called powder including the powder formed into pellets.

FIG. 2 shows an example in which the powder of the object to be inspected is accommodated in a container (powder container) and the container is conveyed by a conveyor.
FIG. 2A is a plan view, and FIG. 2B is a cross-sectional view of the X2-X2 portion of FIG.
The inspected powder 4H stored in the container 41 is moved between the magnetic poles P1 and P2 by the conveyor 31 in the longitudinal direction of the conveyor 31 (direction perpendicular to the paper surface in FIG. 2B). The magnetic flux generated by the coils C1 and C2 flows back through the magnetic path of the yoke Y, the magnetic pole P1, the device under test 4H, the magnetic pole P2, and the yoke Y.
When the metal foreign matter 4K is mixed in the inspection object 4H, an eddy current is induced in the metal foreign matter 4K by the magnetic flux and Joule heat is generated. The temperature distribution of the inspection object 4H is photographed with an infrared camera. Imaging with the infrared camera is performed from above the inspection object 4H (in a direction perpendicular to the paper surface in FIG. 2A).
The container for storing the powder may be a bag of plastic or the like.

FIG. 3 shows an example in which the powder of the object to be inspected is formed into a cylindrical pellet and the pellet is conveyed by a conveyor. 3A is a plan view, and FIG. 3B is a cross-sectional view in the direction of the arrow of the portion X3-X3 in FIG. 3A.
The inspection object 4P in which the powder is formed into a pellet is disposed between the magnetic poles P1 and P2 so that the longitudinal direction thereof is orthogonal to the moving direction, and is conveyed by the conveyor 31. In that case, if the recessed part which mounts the to-be-inspected object 4P in the conveyor 31 is formed, the to-be-inspected object 4P can be conveyed in the stable state.
In this example, when the device under test 4P is a magnetic oxide, the device under test 4P forms a magnetic path. Therefore, even when the distance (magnetic gap) between the magnetic poles P1 and P2 is large, the loss of magnetic flux is small. Therefore, in this example, metal foreign matter can be detected even when the inspection object 4P is a long magnetic oxide.
The pellet-shaped inspection object 4P is formed by kneading powder with water, alcohol, solvent or the like and molding it. The shape of the inspection object 4H is not limited to a columnar shape, and may be a cylindrical shape, a green sheet, a plate shape, a rod shape, a granular shape, or the like. The same applies to each figure below.

FIG. 4 shows an example in which the powder of the object to be inspected is formed into a cylindrical pellet, and the pellet is placed on a holding member and conveyed by a conveyor.
4A is a plan view, and FIG. 4B is a cross-sectional view in the arrow direction of the X4-X4 portion of FIG. 4A.
The object to be inspected 4P formed in a pellet shape is arranged between the magnetic poles P1 and P2 so that the longitudinal direction thereof is parallel to the moving direction, is placed on the holding member 32, and is conveyed by the conveyor 31.
In this example, since the interval between the magnetic poles P1 and P2 can be reduced, the loss of magnetic flux can be reduced even when the inspection object 4P is a non-magnetic material such as ceramics.

FIG. 5 shows an example in which the device under test moves in the solenoid coil.
5A is a plan view, FIG. 5B is a cross-sectional view of the X51-X51 portion in FIG. 5A, and FIG. 5C is the X52-X52 portion in FIG. 5A. It is sectional drawing of the arrow direction.
The inspection object 4P formed in a pellet shape is placed on the holding member 32 and moves in the solenoid coil C3 together with the conveyor 31. The magnetic flux generated by the solenoid coil C3 forms a magnetic path including the device under test 4P. Imaging of the inspection object 4P by the infrared camera is performed at a position where the inspection object 4P passes through the solenoid coil C3.
Since the device under test 4P is placed in the magnetic path in the solenoid coil C3, the magnetic flux generated by the solenoid coil C3 is efficiently concentrated on the device under test 4P.

FIG. 6 shows a specific example of the metal foreign object detection device according to the embodiment of the present invention.
The inspected object shooter 50 supplies pellet-shaped inspected objects one by one to the insertion port 521. The extruding device 51 extrudes the object to be inspected in the insertion port portion 521 one by one into the conveying glass tube 33. The inspected object shooter 50 and the extrusion device 51 are operated by a drive control unit 53. Each time the object to be inspected is pushed out from the insertion port 521, a switch (described later) is activated to send a signal to the object under inspection confirming part 54. The inspecting object confirmation unit 54 sends a signal to the drive control unit 53 and the magnetization control unit 57 when it is confirmed that the inspected object is pushed out from the insertion port 521 and the insertion port 521 is empty.

The magnetization control unit 57 operates the energization switch 58, and the energization switch 58 operates the magnetization power supply circuit 55 and the imaging start signal circuit 56. The magnetization power supply circuit 55 supplies an excitation current to the coil C of the magnetizer M. The shooting start signal circuit 56 operates the shooting control circuit 22. The photographing control circuit 22 starts photographing with the infrared camera 21 after a predetermined time. The predetermined time is determined in consideration of the time until the coil C generates magnetic flux and the metal foreign object on the object to be inspected is heated.
On the other hand, when the drive control unit 53 confirms that the object to be inspected in the insertion port 521 is pushed out and the insertion port 521 is empty, the drive control unit 53 takes a predetermined time in consideration of the imaging time of the infrared camera 21 and the excitation time of the coil C. After the time, the inspected object shooter 50 and the extrusion device 51 are operated, and the process proceeds to the supply of the next inspected object and the extrusion process.
The monitor 23 displays the temperature distribution waveform or temperature distribution image of the object to be inspected based on the imaging signal from the imaging control circuit 22. In addition, the foreign object detection circuit 24 determines the presence or absence of a metal foreign object mixed in the object to be inspected, and sends a foreign object detection signal to the discharge unit 522 when a metal foreign object exists. The discharge unit 522 eliminates an object to be inspected in which a metallic foreign object is mixed by opening a shutter (described later).

  Here, the object to be inspected was a pellet in which iron powder was mixed with ferrite powder. The object to be inspected is obtained by kneading ferrite powder having a particle size of 6 to 20 μm and iron powder having a size of about 50 μm using a liquid containing water as a main component, and forming the pellet into a pellet having a diameter of 13 mm and a length of 20 mm. The dried one was used. The magnetizer M was composed of a ferrite yoke Y having a cross section of 30 mm square and two coils wound with a formal wire having a diameter of 2 mm 600 times. The conveyance glass tube 33 has an outer diameter of 16 mm and a hollow portion with an inner diameter of 14 mm. The inner diameter of the hollow portion is preferably about +5 to 8% of the diameter of the object to be inspected. The excitation current supplied to the coil C was a high-frequency current of 25 to 70 kHz, and the excitation time for one time was set to 1 to 20 seconds. Mixing of iron powder could be detected by this metallic foreign object detection device.

FIG. 7 shows details of the magnetizer M and the transport glass tube 33 of FIG.
FIG. 7A is a side view, and FIG. 7B is a cross-sectional view in the arrow direction of the X7-X7 portion of FIG. 7A.
The coil C in FIG. 6 includes two coils C1 and C2. The dimensions of the tips of the magnetic poles P1 and P2 are set in consideration of the diameter of the inspection object 4P so that the magnetic flux generated by the coils C1 and C2 is concentrated on the inspection object 4P.
Since the transport glass tube 33 has translucency, the imaging of the inspection object 4P by the infrared camera 21 can be performed from outside the transport glass tube 33.

FIG. 8 shows details of the to-be-inspected shooter 50, the extrusion device 51, the insertion port 521, and the discharge unit 522 of FIG.
FIG. 8A is a side view, and FIG. 8B is a cross-sectional view in the arrow direction of the X81-X81 portion of FIG. 8A. 8A is a cross-sectional view of the X82-X82 portion in FIG. 8B in the arrow direction.
FIG. 8 shows an example in which SP5 to SP7 are in the inspected object shooter 50, SP4 is in the insertion port 521, and SP1 to SP3 are in the transport glass tube 33. The state where the body SP2 is placed in the magnetic path of the magnetizer M and is photographed by the infrared camera 21 is shown.

When imaging of the inspection object SP2 is completed, the inspection objects SP1 to SP4 move one by one to the left in FIG. 8A, and the inspection objects SP5 to SP7 fall one by one.
First, the arm 511 of the extrusion device 51 is actuated by the drive control unit 53 (FIG. 6), and the arm 511 pushes the object SP4 to the position of the object SP3 against a spring (not shown). The arm 511 returns to the position shown in the figure by the spring when the test object SP4 is pushed out to the position of the test object SP3. With the extrusion, the test objects SP1 to SP3 move one by one to the left. At that time, a switch composed of the light source LT and the light receiving element LT provided at the outlet of the insertion port 521 detects the passage and the end of passage of the inspection object SP4.
Next, the drive control unit 53 operates the shutter S1 and the shutter S2 by a signal from the switch. First, the shutter S1 is opened, and the inspection object SP5 falls to the insertion port 521. At that time, the shutter S2 is in the position shown in the figure and prevents the object SP6 from dropping. When the shutter S1 returns to the position shown in the figure, the shutter S2 is opened and the object SP6 is dropped onto the shutter S1. When the inspection object SP6 falls to the shutter S1, the shutter S2 returns to the position shown in the figure and enters between the inspection object SP6 and the inspection object SP7. And the extrusion apparatus 51 transfers to the next extrusion process.

  When the test objects SP1 to SP3 move to the left one by one, the test object SP1 moves onto the shutter S3. Here, when a metal foreign object of the inspection object SP1 is detected by the previous photographing by the infrared camera 21, the shutter S3 is opened by the foreign object detection signal of the foreign object detection circuit 24 (FIG. 6), and the inspection object SP1 is The product falls to the non-defective product collection unit 5221. On the other hand, when no metal foreign matter is mixed in the inspection object SP1, it falls to the non-defective product collecting unit 5222 in the next movement process.

It is a block diagram of the metallic foreign material detection apparatus which concerns on embodiment of this invention. It is a figure which shows the example which accommodates the powder of the to-be-inspected object which concerns on embodiment of this invention in a container, and conveys the container with a conveyor. It is a figure which shows the example which shape | molds the powder of the to-be-inspected object which concerns on embodiment of this invention into a cylindrical pellet, and conveys the pellet with a conveyor. It is a figure which shows the example which shape | molds the powder of the to-be-inspected object which concerns on embodiment of this invention into a cylindrical pellet, mounts the pellet on a holding member, and conveys with a conveyor. It is a figure which shows the example which mounts the pellet on a holding member and conveys with a conveyor. It is a figure which shows the specific example of the metal foreign material detection apparatus which concerns on embodiment of this invention. It is a figure which shows the detail of the magnetizer M and the glass tube 33 for conveyance of FIG. FIG. 8 is a diagram illustrating details of the inspected object shooter 50, the extrusion device 51, the insertion port portion 521, and the discharge portion 522 of FIG. It is a block diagram of the conventional electromagnetic induction type metal foreign object detection apparatus.

Explanation of symbols

21 Infrared camera 22 Imaging control circuit 23 Monitor 24 Foreign matter detection circuit 3, 31 Conveyor 32 Holding member 33 Glass tube for conveyance 50 Inspected object shooter 51 Extruding device 511 Arm 521 Insertion port 522 Discharge unit 5221 Defective product collection unit 5222 Non-defective product collection Unit 53 Drive control unit 54 Inspected object confirmation unit 55 Magnetized power supply circuit 56 Imaging start signal circuit 57 Magnetization control unit 58 Current switch circuit 4, 4H, 4P Inspected object 4P1 to 4P7 Inspected object 4K Metallic foreign matter C, C1, C2 , C3 Coil M Magnetizers P1, P2 Magnetic poles S1, S2, S3 Shutter Y Yoke

Claims (4)

A magnet for generating a high-frequency magnetic flux by forming a magnetic path of the yoke, the magnetic pole, the test object, the magnetic pole, and the yoke, and a magnetic pole of the magnetic path of the high-frequency magnetic flux. A conveyance glass tube for holding a non-conductive material powder molded object to be inspected between the magnetic pole and the magnetic pole, and an infrared camera for measuring the temperature distribution of the inspection object from outside the conveyance glass tube Metal foreign object detection device characterized by the above.   The metal foreign object detection device according to claim 1, wherein the non-conductive material powder is an electric / electronic material powder such as ceramics, resin, or magnetic oxide. A high-frequency magnetic flux generating coil, a yoke, and two magnetic poles, using a magnet that forms the magnetic path of the yoke, magnetic pole, object to be inspected, magnetic pole, and yoke, and a conveying glass tube between the magnetic pole of the magnetic path and the magnetic pole was placed, transported glass temperature distribution in the conveyance metal foreign substance of the test subject during the molding of the glass tube to hold the non-conductive material powder was induction heating, the object to be inspected by magnetic flux generated by the magnetizer A method for detecting a metal foreign object, wherein the metal foreign object is detected by measuring with an infrared camera from outside the tube .   The metal foreign matter detection method according to claim 3, wherein the non-conductive material powder is an electric / electronic material powder such as ceramics, resin, magnetic oxide or the like.

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