JP2011058822A - Mirror unit, and device for borehole inspection with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mirror unit capable of collectively illuminating a predetermined depth range by a simple structure, and a device for borehole inspection with the same. <P>SOLUTION: The mirror unit is configured to condense the irradiation light of the ring illuminator provided around an imaging camera to the predetermined depth range on the optical axis of the imaging camera and equipped with the cone-shaped mirror arranged on the same axis as the optical axis to reflect the irradiation light. The mirror has a plurality of fan-shaped mirror piece parts arranged so that the angle of the irradiation light changes stepwise circumferentially. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a mirror unit that collects irradiation light of ring illumination provided around an imaging camera in a predetermined depth range on an optical axis of the imaging camera, and an in-hole inspection apparatus including the mirror unit.

  When ring illumination is used for in-hole inspection for inspecting foreign matter adhering to the inner peripheral surface of the hole formed in the inspection object, the illumination light of the ring illumination is condensed to sufficiently illuminate the inside of the hole. It is necessary to adjust so that the position of the light spot is on the optical axis of the imaging camera. As the related art, in order to widen the depth range in which good illumination can be performed on the hole, the plurality of array-shaped light sources constituting the ring illumination are adjusted by tilting the substrate holding the respective illumination angles ( A ring illumination device that varies a condensing point has been proposed (see Patent Document 1).

JP 2007-287456 A

  However, the ring illumination device described above always determines a condensing point at one point, and in order to illuminate at different depths, it is necessary to tilt the light source substrate a plurality of times over a predetermined range. The predetermined depth range cannot be illuminated. Furthermore, since the above-described ring illumination device tilts the light source substrate, there is a problem that the structure of the illumination unit becomes complicated.

  An object of the present invention is to provide a mirror unit that can illuminate a predetermined depth range collectively with a simple structure, and an in-hole inspection apparatus including the mirror unit.

  The mirror unit of the present invention is a mirror unit that collects irradiation light of ring illumination provided around the imaging camera in a predetermined depth range on the optical axis of the imaging camera, and is coaxial with the optical axis. It is provided with a cone-shaped mirror part that reflects the irradiation light, and the mirror part has a plurality of fan-shaped mirror pieces arranged so that the reflection angle of the irradiation light changes stepwise in the circumferential direction. It is characterized by being.

  According to the above configuration, the plurality of mirror pieces constituting the cone-shaped mirror part are arranged in the circumferential direction so that the angle of the irradiation light changes stepwise, and thus reflected from each mirror piece part. Irradiation light can be collected over a predetermined depth range on the optical axis. For this reason, it is possible to collectively illuminate a predetermined depth range on the optical axis without moving the mirror portion, that is, with a simple structure. The plurality of mirror piece portions may be formed by polishing the surface of the mirror portion to give a mirror finish, or may be formed by arranging a plurality of mirror pieces having the surface as a mirror finish in the circumferential direction.

  In this case, it is preferable that the reflection angles of any two mirror pieces disposed at a 180 ° point symmetrical position among the plurality of mirror pieces are the same angle.

  According to said structure, since the irradiation light which opposes is irradiated with the same reflection angle, the stable illumination with much light quantity can be performed with respect to arbitrary 1 depth on the optical axis of an imaging camera.

  Another mirror unit of the present invention is a mirror unit that collects the irradiation light of the ring illumination provided around the imaging camera in a predetermined depth range on the optical axis of the imaging camera, and is coaxial with the optical axis. It has a cone-shaped mirror part that is disposed above and reflects irradiated light, and the mirror part is formed so that the reflection angle of illumination light continuously changes in the circumferential direction.

  According to the above configuration, since the reflection angle of the illumination light is continuously changed in the circumferential direction in the cone-shaped mirror portion, the irradiation light reflected from the mirror portion is predetermined on the optical axis. Can be collected over a range of depths. In this case, all of the irradiation light of the ring illumination can be condensed in a predetermined depth range by the reflection angle that continuously changes, and the light can be condensed with high efficiency. For this reason, it is possible to illuminate a predetermined depth range on the optical axis collectively and efficiently without moving the mirror portion, that is, with a simple structure.

  In this case, the mirror part is preferably formed so that the reflection angle at the 180 ° point-symmetrical position is the same angle.

  According to said structure, since the irradiation light which opposes is irradiated with the same reflection angle, the stable illumination with much light quantity can be performed with respect to arbitrary 1 depth on the optical axis of an imaging camera.

  The in-hole inspection apparatus according to the present invention is an in-hole inspection apparatus that inspects foreign matter adhering to the inner peripheral surface of a hole formed in an inspection object, and images a hole in a state where the surface position of the inspection object is focused. An imaging camera to be recognized, a ring illumination provided around the imaging camera to illuminate the hole, and the mirror unit described above are provided.

  According to the above configuration, in the depth direction, by capturing images in a plurality of holes having different depths with a sufficient amount of illumination light while the imaging camera is focused on the surface position of the inspection object. Regardless of the position of the foreign matter in the hole, the hole and the foreign matter can be imaged relatively clearly.

  In this case, it is preferable that the inspection object is a nozzle plate of the ink jet head and the hole is a nozzle hole formed in the nozzle plate.

  According to said structure, the presence or absence and the magnitude | size of the foreign material adhering in the nozzle hole formed in the nozzle plate of an inkjet head can be test | inspected accurately.

It is sectional drawing which represented the inkjet head typically. It is the figure which represented typically the inspection apparatus in a hole. It is the top view and sectional view of a mirror unit concerning a 1st embodiment. It is the top view and sectional drawing of the mirror unit which concern on 2nd Embodiment. It is the figure which represented a mode that the irradiation light of ring illumination was condensed.

  Hereinafter, a mirror unit and an in-hole inspection apparatus including the mirror unit according to an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the in-hole inspection apparatus of this embodiment is intended for inspection of a large number of nozzle holes formed on the nozzle surface of an ink jet head, and inspects foreign matter adhering to the nozzle holes at the final stage of head assembly. Is. Therefore, the in-hole inspection is performed by illumination from the nozzle surface and image recognition from the nozzle surface.

  Two nozzle rows are formed in parallel on the nozzle plate 2 (nozzle surface 5) of the inkjet head 1 to be inspected, and each nozzle row has a plurality of nozzle holes 3 arranged at equal pitches. It consists of As shown in FIG. 1, the nozzle hole 3 is formed perpendicular to the nozzle plate 2, and is formed in a tapered shape from a position (meniscus formation position 6) from the front surface to a predetermined depth to the back surface. Yes. In-hole inspection to be described later, the nozzle plate 2 was imaged from the nozzle surface 5 side, and the inner peripheral surface 4 of the nozzle hole 3 was adhered over a predetermined depth range (depth range) with the meniscus formation position 6 as the center. Inspect for foreign objects.

  As shown in FIG. 2, the in-hole inspection apparatus 10 includes a set stage 11 on which the inkjet head 1 is set upside down, a set stage 11 in the nozzle row direction (X axis direction), and a Y axis direction perpendicular thereto. A moving table 12 to be moved to, an imaging camera 13 that faces the inkjet head 1 from above and images the nozzle hole 3 of the inkjet head 1 from the nozzle surface 5 side, and a nozzle hole 3 that is provided around the distal end of the imaging camera 13. Along with the ring illumination 14 that illuminates from the nozzle surface 5 side, a mirror unit 16A that is disposed below the ring illumination 14 and collects the irradiation light of the ring illumination 14 on the optical axis of the imaging camera 13, and the imaging camera 13, A Z-axis table 15 that raises and lowers the ring illumination 14 and the mirror unit 16A in the Z-axis direction, and a frame that supports these devices. Housing case for housing the whole beauty and a (both not shown). Further, the in-hole inspection apparatus 10 includes a control device 19 that controls driving of the moving table 12, the imaging camera 13, the ring illumination 14, and the Z-axis table 15.

  The set stage 11 is mounted on the moving table 12 and holds the nozzle surface 5 in a horizontal state with the inkjet head 1 turned upside down by a positioning mechanism (not shown). The moving table 12 includes a motor-driven X-axis table 22 that moves the inkjet head 1 in the X-axis direction via the set stage 11, and a motor that moves the inkjet head 1 in the Y-axis direction via the X-axis table 22. And a drive Y-axis table 23. The X-axis table 22 and the Y-axis table 23 are each connected to the control device 19. In the in-hole inspection, the inkjet head 1 is moved by the X-axis table 22 and the Y-axis table 23 so that the central axis of the nozzle hole 3 to be inspected matches the optical axis of the imaging camera 13.

  The imaging camera 13 is disposed so as to face the set stage 11 from above, and is supported by the Z-axis table 15 so as to be movable up and down. In this case, the Z-axis table 15 raises the imaging camera 13 when the inkjet head 1 is carried in / out, and lowers the imaging camera 13 to the reference focus position prior to the in-hole inspection. The imaging camera 13 has an imaging element 24 such as a CCD or CMOS and a lens unit 25 in a lens barrel, determines the focusing distance by driving the Z-axis table 15, and images the nozzle hole 3. The imaging camera 13 and the Z-axis table 15 are each connected to the control device 19. A camera with epi-illumination may be used as the imaging camera 13.

  The ring illumination 14 is provided around the distal end portion of the imaging camera 13 and includes a plurality of LEDs (not shown) built in a ring shape on the surface facing the nozzle plate 2. The plurality of LEDs constitutes a ring-shaped LED array and functions as a surface emitting light source. The surface of the nozzle hole 3 including the peripheral edge and the inner peripheral surface 4 are illuminated by the irradiation light from the plurality of LEDs. The ring illumination 14 is mounted with a uniform inclination at a desired angle so that the irradiation light can be properly condensed on the optical axis of the imaging camera 13 via the mirror unit 16A. The ring illumination 14 is connected to the control device 19 and illuminates the nozzle hole 3 when the imaging camera 13 captures an image. Note that the ring illumination 14 may be one in which the irradiation angle of the irradiation light is parallel to the optical axis of the imaging camera 13.

  The mirror unit 16 </ b> A is disposed coaxially with the imaging camera 13 and the ring illumination 14, and reflects the light emitted from the ring illumination 14 toward the nozzle hole 3, and a support frame (illustrated) that supports the mirror unit 20. (Omitted). As shown in FIG. 3, the mirror unit 20 has a plurality of mirror pieces 30 which are formed in an elongated strip shape or an elongated fan shape, and whose surfaces are mirror-finished. 13 are arranged in a cone shape in the circumferential direction around the optical axis, and the inclination angle with respect to the set stage 11 is changed stepwise between 180 degrees in the circumferential direction. Further, the plurality of mirror piece portions 30 are arranged to face each other by 180 degrees so that the inclination angles of the opposing mirror piece portions 30 are the same angle.

  In this case, the plurality of mirror piece portions 30 are formed by grinding a metal block constituting the mirror portion 20 and mirror finishing, and the angle difference between any two adjacent mirror piece portions 30 is constant. Yes. Of course, the mirror piece 30 and the metal block may be separated and the mirror piece 30 may be attached to the surface of the metal block at a predetermined angle.

  As described above, the mirror unit 16A of the present embodiment is configured such that the inclination angles of the plurality of mirror pieces 30 change stepwise between 180 degrees in the circumferential direction. Similarly, the reflection angle changes stepwise. That is, the irradiation light reflected by the mirror unit 20 irradiates the optical axis of the imaging camera 13 with a certain depth range. Furthermore, since the mirror unit 16A is disposed to face each other by 180 degrees, irradiation light that faces any one point on the optical axis irradiates the same depth position, and stable illumination with a large amount of light can be performed.

  Next, the collection of irradiation light from the ring illumination 14 will be described with reference to FIG. The irradiation light X irradiated from the ring illumination 14 is reflected by the mirror unit 20 at the same angle as the incident angle with respect to the mirror unit 20 (mirror piece unit 30), and irradiates the nozzle hole 3. As shown in the figure, the mirror piece 30 a has a small inclination angle a with respect to the nozzle plate 2, so that the reflection angle of the irradiation light X is large and irradiates a position A having a shallow depth on the optical axis of the imaging camera 13. . On the other hand, since the mirror piece 30b has a large inclination angle b with respect to the nozzle plate 2, the reflection angle of the irradiation light X is reduced, and the position B having a deep depth on the optical axis of the imaging camera 13 is irradiated. Since the plurality of mirror pieces 30 of the mirror unit 20 are configured to change the reflection angle in a stepwise manner within a range from the angle a to the angle b, the mirror unit 20 is configured such that the mirror unit 20 has A to B on the optical axis. It is possible to irradiate the depth range up to.

  Here, the in-hole inspection by the in-hole inspection apparatus 10 provided with the mirror unit 16A will be described. The in-hole inspection is sequentially performed on all the nozzle holes 3 formed in the nozzle plate 2, and each nozzle hole 3 is illuminated and imaged from the nozzle surface 5 side, and the nozzle hole 3 around the meniscus formation position 6. The inner peripheral surface 4 is inspected for the presence or absence of the foreign matter 50 over a predetermined depth range (depth range).

  First, various devices are driven by the control device 19, and the X-axis table 22 and the Y-axis table 23 are adjusted so that the central axis of the nozzle hole 3 to be inspected coincides with the optical axis of the imaging camera 13. The imaging camera 13 is moved up and down by 15 to focus on the surface position of the nozzle hole 3. With the focus position fixed at the surface position of the nozzle hole 3, the nozzle hole 3 is imaged while collectively illuminating a predetermined depth range on the optical axis by the ring illumination 14 and the mirror unit 16A.

  Since the in-hole inspection apparatus 10 of the present embodiment captures an image by reflecting and illuminating the nozzle hole 3, the picked-up image picked up in the image pick-up step is the surface of the nozzle hole 3 (nozzle surface 5) and the inside thereof. The foreign matter attached to the peripheral surface 4 is bright and the inside of the nozzle hole 3 is displayed dark. Moreover, the part irradiated with much light quantity of the ring illumination 14 is expressed brighter. As described above, the in-hole inspection apparatus 10 images the nozzle hole 3 while collectively illuminating a predetermined depth range on the optical axis, and therefore illuminates substantially uniformly foreign matters having different attachment positions in the depth direction. In the picked-up image of the nozzle hole 3, a plurality of foreign matters having different attachment positions in the depth direction are simultaneously displayed relatively clearly. Furthermore, the captured image of the nozzle hole 3 is binarized to enhance the outline of the nozzle hole 3 and the outline of the foreign matter attached to the inner peripheral surface 4. The binarized specimen image is processed such that the surface of the nozzle hole 3 (nozzle surface 5) and the foreign matter are white and the inside of the nozzle hole 3 is black.

  When a specimen image is generated for one nozzle hole 3, the control device captures the specimen image and recognizes the presence or absence of foreign matter. In actual recognition, the size of the foreign matter is measured based on the processed image, and if a foreign matter having a size exceeding a predetermined size (threshold) is recognized (size that affects ink ejection), “existing foreign matter” Judgment is made.

  When the above steps are completed, the in-hole inspection apparatus 10 raises the imaging camera 13 and the ring illumination 14 with the Z-axis table 15 and separates them from the nozzle plate 2 of the inkjet head 1, and inkjets with the X-axis table 22 and the Y-axis table 23. The head 1 is moved, and the nozzle hole 3 to be inspected next is arranged immediately below the imaging camera 13. By repeating the above steps, in-hole inspection is performed on all the nozzle holes 3 of the inkjet head 1.

  As described above, according to the in-hole inspection device 10, the nozzle hole 3 hole is irradiated with a sufficient amount of illumination light having a depth range on the optical axis while the imaging camera 13 is focused on the surface position of the nozzle hole 3. By picking up the image inside the nozzle hole 3, the nozzle hole 3 and the foreign substance can be picked up relatively clearly regardless of the position of the foreign substance in the nozzle hole 3 in the depth direction. It is possible to accurately inspect for the presence and size of adhered foreign matter.

(Second Embodiment)
Subsequently, a mirror unit 16B according to a second embodiment of the present invention will be described with reference to FIG. The mirror unit 16A is configured such that the inclination angle of the mirror unit 20 with respect to the set stage 11 is changed stepwise in the circumferential direction. However, the mirror unit 16B according to the present embodiment is The difference is that the tilt angle of the mirror unit 20 is configured to continuously change in the circumferential direction. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Moreover, the modification applied about the component similar to 1st Embodiment is applied similarly about this embodiment.

  As shown in FIG. 4, the mirror unit 16 </ b> B is disposed coaxially with the imaging camera 13 and the ring illumination 14, and reflects the irradiation light of the ring illumination 14 toward the nozzle hole 3, and the mirror unit 20. And a support frame (not shown). The mirror unit 20 has a mirror-finished surface, is formed in a cone shape in the circumferential direction around the optical axis of the imaging camera 13, and condenses the irradiation light of the ring illumination 14 on the optical axis of the imaging camera 13. In this case, the mirror unit 20 is configured such that the inclination angle with respect to the set stage 11 continuously changes in the circumferential direction, and is disposed so as to face each other so that the opposing inclination angles become the same angle.

  As described above, the mirror unit 16B of the present embodiment is configured so that the inclination angle of the mirror unit 20 continuously changes between the circumferential directions of 180 degrees and is disposed to face each other by 180 degrees. Irradiated light reflected by the light is irradiated on the optical axis of the imaging camera 13 with a certain depth range. Further, since the mirror unit 16A continuously changes the reflection angle of the irradiation light, the entire irradiation light of the ring illumination can be condensed in a predetermined depth range, and the light can be condensed with high efficiency. Can do.

  Furthermore, according to the in-hole inspection apparatus 10 provided with the mirror unit 16B, an image in the three nozzle holes can be picked up by illumination light with a sufficient amount of light having a depth range on the optical axis. The presence / absence and size of the foreign matter adhering to the hole 3 can be accurately inspected.

    1: Inkjet head 2: Nozzle plate 3: Nozzle hole 13: Imaging camera 14: Ring illumination 16A, 16B: Mirror unit 20: Mirror part 30: Mirror piece part

Claims (6)

A mirror unit that collects the irradiation light of the ring illumination provided around the imaging camera in a predetermined depth range on the optical axis of the imaging camera,
It is arranged coaxially with the optical axis, and comprises a cone-shaped mirror part that reflects the irradiation light,
The mirror unit has a plurality of fan-shaped mirror pieces arranged so that the reflection angle of the irradiation light changes stepwise in the circumferential direction.   2. The reflection angle of any two of the plurality of mirror piece portions arranged at a 180 [deg.] Point symmetrical position is set to be the same angle. Item 2. The mirror unit according to Item 1. A mirror unit that collects the irradiation light of the ring illumination provided around the imaging camera in a predetermined depth range on the optical axis of the imaging camera,
It is arranged coaxially with the optical axis, and comprises a cone-shaped mirror part that reflects the irradiation light,
The mirror unit is formed so that a reflection angle of the illumination light continuously changes in a circumferential direction.   The mirror unit according to claim 3, wherein the mirror unit is formed so that the reflection angle at a 180 ° point-symmetrical position is the same angle. An in-hole inspection device for inspecting foreign matter adhering to the inner peripheral surface of a hole formed in an inspection object,
An imaging camera that recognizes the hole in an image in a state where the surface is focused on the inspection object
A ring illumination provided around the imaging camera to illuminate the hole;
An in-hole inspection apparatus comprising: the mirror unit according to claim 1. The inspection object is a nozzle plate of an inkjet head;
The in-hole inspection apparatus according to claim 5, wherein the hole is a nozzle hole formed in the nozzle plate.

Images