JP2005049590A - Image pickup apparatus adjustment method and detection jig used in the adjustment method - Google Patents

Abstract

An imaging apparatus adjustment method capable of accurately and easily adjusting an optical axis of an imaging apparatus, an inclination detection jig used in the adjustment method, and an inclination adjustment apparatus are provided.
A first plate having a first fiducial mark that can be detected optically, and a second fiducial mark that is optically detectable while being opposed to and parallel to the first plate. The detection jig 40 provided with the 2nd board which has is prepared. The positional relationship between the first and second reference marks in the detection jig is measured in advance, and the measured value is stored as reference data. A detection jig is mounted on the mounting table 14 on which the measurement object is mounted horizontally, and the imaging device 20 images the detection jig from above the mounting table. Based on the captured image, the positional relationship between the first and second reference marks is detected and used as detection data, and the inclination of the optical axis of the imaging device is adjusted so that the detection data matches the reference data.
[Selection] Figure 2

Description

  The present invention relates to an adjustment method for adjusting an inclination of an optical axis of an image pickup device and a detection jig used for the adjustment method in a position measurement device including the image pickup device.

  As a method of measuring the position of an object, an object having optical characteristics such as an alignment mark is photographed by an imaging device such as a CCD camera, and the obtained photographed image is analyzed by an image processing device or the like. A measurement method for measuring the position is known. This measuring method is used, for example, for a substrate alignment device (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3) in an exposure apparatus, and an alignment device (for example, Patent Document 4) in a screen printing apparatus. ing. In addition, this measuring method is a device for aligning substrates in the manufacture of lightweight and thin display devices that have been actively developed in recent years, such as a device for aligning substrates of liquid crystal displays (for example, patent documents). 5), or a positioning device for an outer container for a display device (for example, see Patent Document 6).

  In recent years, display devices such as those described above have been improved in definition with the progress of technological development, and higher accuracy has been demanded for alignment during manufacturing. For example, as a thin display device, a field emission display (hereinafter referred to as FED) that emits a phosphor by an electron beam emitted from a field emission electron-emitting device, and a phosphor by an electron beam of a surface conduction electron-emitting device. A surface-conduction electron-emission display (hereinafter referred to as SED) that normally emits light has a front substrate and a rear substrate that are opposed to each other with a predetermined gap therebetween, and a phosphor screen formed on the inner surface of the front substrate; Therefore, it is required to accurately match the position of the electron emission source formed on the inner surface of the back substrate in units of micrometers.

  When such high-accuracy alignment is required, in order to perform accurate measurement by the measurement method using the imaging device as described above, the imaging device itself is adjusted with high accuracy with respect to the measurement object. It is important to do. In particular, the perpendicularity of the optical axis of the imaging device with respect to the measurement object is important. For example, when two substrates as measurement objects are opposed to each other with a predetermined gap, such as an FED or SED, the optical axis of the imaging device is inclined with respect to an axis perpendicular to the substrate plane. In addition, an error that is uniquely expressed by the distance of the gap between the substrates and the axis inclination angle occurs in the measurement accuracy of the alignment mark or the like. Therefore, it is necessary to adjust the optical axis with high accuracy. This adjustment makes it difficult to visually confirm the optical axis, and includes factors that make adjustment difficult, such as the degree of perpendicularity between the camera that is the image pickup apparatus and the image pickup element in the camera.

As the optical axis adjustment method of the image pickup apparatus, (1) accurate optical axis adjustment (tilt) is not performed, the measurement data at the time of alignment adjustment, and the amount of alignment shift measured using a dedicated measuring instrument after sealing (2) A method for adjusting the optical axis using a reference substrate that has already been measured for alignment, (3) A method for adjusting the optical axis using a jig that has marks on the front and back surfaces using a plotter or the like. And (4) a method of adjusting the optical axis by providing coaxial pinholes on the front and back surfaces of the reference block and measuring the pinhole diameter by image processing.
JP 2002-333721 A JP 2002-288678 A JP 2002-55458 A JP 2002-234131 A JP 2002-257514 A Japanese Patent Laid-Open No. 10-55754

  However, with the adjustment method (1) described above, it takes a long time to determine the correction value and management becomes difficult. In the adjustment method (2), it is difficult to handle and manage the reference substrate after the alignment measurement. In the adjustment method (3) above, there is a risk that an error will occur in the mark drawing positions on the front and back surfaces due to the changeover of the front and back surfaces during jig creation. Furthermore, in order to correct this drawing position error, it becomes difficult to measure the drawing positions of the marks on the front and back surfaces three-dimensionally. In the adjustment method (4) described above, a processing error typified by a position error at the time of pinhole processing and a shape error such as roundness adversely affects the measurement value result at the time of adjustment using a jig. Therefore, with the conventional adjustment method described above, it is difficult to easily adjust the optical axis of the imaging apparatus.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an imaging device adjustment method capable of accurately and easily adjusting the optical axis of the imaging device, and a detection jig used in the adjustment method. There is.

  In order to achieve the above object, an image pickup apparatus adjustment method according to an embodiment of the present invention includes an image pickup apparatus adjustment method for adjusting an optical axis of an image pickup apparatus with respect to a measurement object. A detection jig comprising: a first plate having a first plate, and a second plate having a second reference mark that is optically detectable while being opposed to the first plate with a gap. The positional relationship in the horizontal plane between the first and second reference marks is measured in advance with the plane reference of the first plate, the measured value is stored as reference data, and the measurement object is placed horizontally. The detection jig is placed on a mounting table in a state where the first and second plates are horizontal, and the detection jig is imaged by the imaging device from above the mounting table. Based on the captured image Detect the positional relationship between the first and second fiducial marks And detection data, as described above detected detected data and the stored reference data are match is characterized by adjusting the inclination of the optical axis of the imaging device.

In addition, the detection jig according to the embodiment of the present invention used for the adjustment method of the imaging device described above includes a first plate in which one optically detectable first pinhole is formed, and a gap between the first plate and the first plate. A second plate having a plurality of optically detectable second pinholes disposed opposite to each other in parallel,
The second pinhole is provided so as to be shifted in the surface direction of the first plate with respect to the first pinhole. The first plate faces the second pinhole, and the second pinhole. A plurality of first observation holes having a larger diameter, and the second plate has a second observation hole facing the first pinhole and having a larger diameter than the first pinhole. It is characterized by having.

  According to the present invention, it is possible to provide an adjustment method for an image pickup apparatus capable of accurately and easily adjusting the optical axis of the image pickup apparatus, and a detection jig used for the adjustment method.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an SED alignment adjusting apparatus according to an embodiment of the present invention, an optical axis adjusting method of an imaging apparatus in the adjusting apparatus, and a detection jig for tilt detection used for optical axis adjustment will be described in detail with reference to the drawings. To do.

  As shown in FIG. 1, an alignment adjustment apparatus 10 that adjusts alignment between a pair of substrates constituting an SED includes a mounting table 14 on which a substrate 11 of the SED is mounted horizontally as a measurement object, and the mounting table on a horizontal plane. And a support mechanism 18 for horizontally supporting the other substrate 12 of the SED. The substrates 11 and 12 are provided with alignment marks 11a and 12a, respectively. The mounting table 14 is adjusted with high accuracy so that the substrate 11 can be supported horizontally. Similarly, the support mechanism 18 is adjusted with high accuracy so that the substrate 12 can be supported horizontally. The moving mechanism 16 is configured by, for example, an XY stage.

  The alignment adjustment device 10 includes a camera 20 as an imaging device disposed above the mounting table 14 and the support mechanism 18, a camera adjustment mechanism 22 that supports the camera and can adjust the position of the camera, and the mounting table. 14 and a control unit 24 that functions as an image processing device that processes and stores an image captured by the camera.

  The camera adjustment mechanism 22 includes a movable base 32 that can move in the horizontal direction along the guide rail 30 and a rotation mechanism 34 provided on the movable base 32. The rotation mechanism 34 supports the camera 20 so as to be rotatable around an X axis and a Y axis extending orthogonally to each other in a horizontal plane. The rotating mechanism 34 can rotate the camera about the X axis and the Y axis to adjust the position of the camera 20 with respect to the substrate 11 placed on the mounting table 14 and adjust the optical axis 7 of the camera. it can.

  When the substrates 11 and 12 are aligned with each other by the alignment adjusting device 10, the substrate 11 is placed on the mounting table 14 and the substrate 12 is horizontally supported by the support mechanism 18 as shown in FIG. Place them facing each other. In this state, the camera 20 photographs the alignment marks 11a and 12a provided on the substrates 11 and 12, respectively. The captured image is subjected to image processing by the image processing unit of the control unit 24 to detect position information of the two substrates 11 and 12. Based on this position information, one substrate, for example, the substrate 11 is moved in the horizontal direction by the moving mechanism 16 so that the alignment marks 11a and 12a coincide with each other, and alignment adjustment between the substrates 11 and 12 is performed.

When the alignment mark of the substrate is accurately measured by the alignment adjustment device 10 and alignment is performed with high accuracy, the optical axis 7 of the camera 20 is adjusted vertically with high accuracy with respect to the surfaces of the substrates 11 and 12 to be aligned. There is a need to.
Therefore, according to the present embodiment, prior to alignment adjustment, the optical axis 7 of the camera 20 is adjusted by the following steps. As shown in FIG. 2, instead of the substrate to be measured, a measurement plate 38 made of a flat plate such as aluminum is placed on the mounting table 14. Subsequently, the detection jig 40 is placed on the measurement plate 38.

  As shown in FIGS. 3 and 4, the detection jig 40 includes a rectangular plate-shaped base substrate 42. Both surfaces of the base substrate 42 are formed flat, and one surface forms a reference surface 44. On the reference surface 44, a first level 46 that extends parallel to the long side of the base substrate 42 and a second level 47 that extends parallel to the short side of the base substrate are provided. The first level 46 detects the inclination of the reference surface 44 around an axis parallel to the short side of the base substrate 42, for example, the Y axis. The second level 47 detects the inclination of the reference plane 44 around an axis parallel to the long side of the base substrate 42, for example, the X axis orthogonal to the Y axis.

  For example, three height adjustment screws 48 are provided on the base substrate 42 as a horizontal adjustment mechanism. These height adjusting screws 48 are spaced apart from each other at three locations on the base substrate 42. Each height adjustment screw 48 is screwed into the base substrate 42 from the reference surface 44 side, and its lower end protrudes downward from the base substrate. Then, by adjusting the screwing amount of the height adjusting screw 48 and adjusting the protruding amount of the height adjusting screw from the base substrate 42, the inclination of the base substrate can be adjusted, and the reference plane 44 can be leveled. it can.

  For example, a circular detection hole 49 is formed through the base substrate 42, and the front plate 50 and the rear plate 52 are screwed to the reference surface 44 and the opposite surface of the base substrate with the detection hole 49 interposed therebetween. The detection hole 49, the front plate 50, and the rear plate 52 constitute a detection unit 51.

  As shown in FIGS. 3 to 7, the front plate 50 has one pinhole 54a, one direction confirmation hole 55, and 4 around the pinhole 54a as optically detectable reference marks. A plurality of observation holes 56 are formed. Each observation hole 56 has a sufficiently large diameter with respect to the pinhole 54a. The front plate 50 is fixed on the reference surface 44 with these pinholes 54 a, direction confirmation holes 55, and observation holes 56 facing the detection holes 49.

  The back plate 52 is formed with one observation hole 60, one direction confirmation hole 62, and four pinholes 64 a positioned around the observation hole 60. Each pinhole 64a provided as an optically detectable reference mark is formed to have a diameter substantially equal to that of the pinhole 54a of the front plate 50. The observation hole 60 has a diameter substantially equal to that of the observation hole 56 on the front plate 50 side, and is formed to have a sufficiently large diameter with respect to each pinhole 64a. The back plate 52 is fixed on the reference surface 44 with the observation hole 60, the direction confirmation hole 62, and the four pin holes 64 a facing the detection hole 49.

Thereby, the front plate 50 and the back plate 52 face each other in parallel with a predetermined gap. The back plate 52 is arranged in a state in which the direction confirmation hole 55 is aligned with the direction confirmation hole 62 on the front plate side. Further, in the back plate 52, each observation hole 60 is substantially coaxially opposed to the pinhole 54a of the front plate 50, and further, four pinholes 64a are respectively substantially coaxial with the observation hole 56 of the front plate. In a state of facing, it is fixed to the back surface of the base substrate 42.
As will be described later, the direction confirmation holes 55 and 62 are provided so as to confirm the direction of the detection jig 40 and to prevent an error when comparing the detection data of the pinhole and the reference data of the detection jig. .

  For the detection jig 40 configured as described above, the positional relationship between the pinholes 54a and 64a is measured by a three-dimensional measuring instrument (not shown) with the front plate 50 and the rear plate 52 fixed to the base substrate 42. As previously measured. In other words, the position of the pinhole 64a formed on the plane of the back plate 52 having an inclination angle caused by a processing error with the plane of the front plate 50 as a plane reference is projected on the plane with the front plate 50 as a horizontal plane. And the positional relationship between the pinholes 54a and 64a is measured as position data in the plane and stored in the control unit 24. More specifically, as shown in FIG. 7, an intermediate position between the center of gravity C1 of one pinhole 54a formed on the front plate 50 and the center of gravity of two pinholes 64a formed on the rear plate 52, for example. As position data indicating the positional relationship with the position C2, the distance D1 between C1 and C2 along the X-axis direction and the distance D2 between C1 and C2 along the Y-axis direction on the plane of the front plate 50 are measured. Keep it. Then, the measured values of the distances D1 and D2 are stored in the control unit 24 as reference data.

  After the detection jig 40 configured in this way is placed on the measurement plate 38, the reference surface 44 is adjusted horizontally by the adjustment screw 48. At this time, the three adjustment screws 48 function as legs of the detection jig and support the detection jig. The reference for adjusting the tilt of the optical axis of the camera 20 is the substrate surface of the back substrate 11 and the front substrate 12 of the SED imaged by the camera. Since the substrate surfaces of the rear substrate 11 and the front substrate 12 mounted on the mounting table 14 are horizontal with high accuracy, it is necessary to adjust the reference surface 44 of the detection jig 40 horizontally when adjusting the optical axis of the camera 20. is there. Here, there is a possibility that the surface of the measurement plate 38 mounted on the mounting table 14 instead of the back substrate 11 is not completely horizontal. Therefore, the adjustment screw 48 is adjusted while looking at the first and second levels 46 and 47 of the detection jig 40, and the base substrate 42 is adjusted so that the reference plane 44 is horizontal.

  Subsequently, the camera 20 is positioned above the detection unit 51 of the detection jig 40 and the illumination jig 23 illuminates the detection jig 40 from below. The measurement plate 38 is formed with an opening through which illumination light from the illumination device 23 passes. In this state, the camera 20 images the detection unit 51 from above and sends the image to the control unit 24. The control unit 24 processes the sent image and calculates the center of gravity position, positional relationship, and distances D1 and D2 of these pinholes from the images of the pinholes 54a and 64a provided on the front plate 50 and the back plate 52. To do. The control unit 24 stores the calculation result as detection data and compares it with reference data of a pinhole measured in advance by a three-dimensional measuring device. As a result of the comparison, it can be seen that when these position data are different, an error due to the inclination of the optical axis 7 of the camera 20 occurs. That is, it can be seen that the optical axis 7 is inclined with respect to the vertical axis. Then, the optical axis 7 is adjusted so that the difference amount of the position data is reduced, and the imaging, image processing, and adjustment are repeated again. Adjustment of the optical axis 7 is performed by rotating the camera 20 around the X and Y axes by the rotation mechanism 34.

  Through the above steps, the optical axis 7 of the camera 20 can be easily adjusted with high accuracy. By adjusting the optical axis 7 of the camera 20 perpendicularly to the surface of the measurement object, the alignment of the substrates 11 and 12 by the alignment adjusting device 10 can be performed with high accuracy. Thereby, it becomes possible to manufacture SED excellent in display performance.

  According to the alignment adjustment device, the optical axis adjustment method, and the detection jig configured as described above, by adjusting the optical axis of the camera based on the image captured by the camera itself as the imaging device, It is possible to eliminate the influence of the assembly error between the image pickup device and the image pickup device casing, which occurs when the outer shape or the attachment portion is adjusted.

  In the detection jig, the mark used as the measurement reference is a circular pinhole, and the position of the center of gravity of the pinhole is obtained by image processing, so that even if the shape is distorted, the position indicated by the mark can be uniquely determined. It can be digitized and the position detection accuracy can be improved.

  In the detection jig, a plurality of pinholes are formed in at least one of the front plate and the back plate arranged to face each other, and the other plate has at least one other pin at a position that does not overlap these pinholes. A hole is formed. A sufficiently large observation hole is formed at a position facing each pinhole of each plate so that an image of the pinhole can be taken by a camera. Thereby, for example, the gravity center position C1 of the image corresponding to one pinhole formed on the front plate is compared with the intermediate position C2 of the distance between the gravity centers of the images corresponding to the two pinholes formed on the rear plate. By doing so, it is possible to eliminate the influence of image vignetting due to position error and shape error of each pinhole.

  It should be noted that the pixel length can be adjusted to a plurality of pinholes by adjusting so that the center of gravity C1 of the pinhole on one side and the middle position C2 of the distance between the centers of gravity of the pinholes on the opposite side coincide. . Further, by adjusting the intermediate position C2 of the distance between the center of gravity to a predetermined position, that is, the center of gravity position C1 of the pinhole on one side, it is possible to reduce the influence of the pixel length difference caused by the distance between the front plate and the back plate. . At this time, due to a processing error, a deviation occurs between the center of gravity C1 of the pinhole on one side and the intermediate position C2 of the distance between the centers of gravity of the pinholes on the opposite side, and this deviation is affected by the pixel length error. Since the amount of deviation is small, the influence on the measurement accuracy can be managed to be extremely small.

  In addition, by correcting the pixel length of the image taken by the imaging device with the data of the pitch between the pinholes of the detection jig measured by the measuring device, the reference data of the detection jig and the image processing using the imaging device It is possible to correlate with detection data, quantitatively grasp the tilt state of the optical axis, and manage the measurement system using image processing.

  An error occurs in the position of the reference mark written on the front plate and the rear plate of the detection jig due to the influence of the drawing accuracy / set-up change accuracy or processing accuracy of the drawing apparatus. If this amount of deviation does not fall within the error range, it is necessary to recognize the amount of deviation in advance and feed it back as reference data for the detection jig. When a fiducial mark is drawn by a photoplotter or printing technology, there are many error factors to measure the position three-dimensionally, making it difficult to measure with high accuracy. According to this embodiment, the reference mark of the detection jig is a mechanically processed pinhole, so that each hole position can be measured using a measuring instrument and measured with three-dimensional data. Become. When adjusting the optical axis, it is possible to reduce the error of the jig by using this jig with data and adjusting it to the amount of deviation.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  For example, in the above-described embodiment, the substrate alignment adjustment device constituting the SED as an adjustment target has been described as an example. However, the present invention is not limited to this, and the alignment adjustment device for a liquid crystal display or a plasma display panel, or The present invention can also be applied to optical axis adjustment in other apparatuses such as an exposure apparatus.

The side view which shows the alignment adjustment apparatus which concerns on embodiment of this invention. The side view which shows the state which mounted the detection jig on the mounting base in the said alignment adjustment apparatus. The top view of the said detection jig. The side view which shows the said detection jig partially fractured | ruptured. The top view which shows the front board and back board of the said detection jig. Sectional drawing which shows the detection part of the said detection jig. The top view of the said detection part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Alignment adjustment apparatus 11 ... Front substrate 12 ... Rear substrate
14 ... mounting table, 16 ... moving mechanism, 18 ... supporting mechanism,
20 ... Camera, 24 ... Control part, 34 ... Rotation mechanism, 40 ... Detection jig,
44 ... reference plane, 46 ... first level, 47 ... second level,
50 ... front plate, 51 ... detector, 52 ... back plate,
54a, 64a ... pinhole, 56, 60 ... observation hole

Claims (7)

In the adjustment method of the imaging device for adjusting the optical axis of the imaging device with respect to the measurement object,
A first plate having a first fiducial mark that can be detected optically, and a second plate having a second fiducial mark that can be optically detected while being opposed to the first plate with a gap. Prepare a detection jig with
Preliminarily measuring the positional relationship in the horizontal plane between the first and second reference marks with the plane reference of the first plate, storing the measured value as reference data,
On the mounting table on which the measurement object is horizontally mounted, the detection jig is mounted in a state where the first and second plates are horizontal,
The detection jig is imaged by the imaging device from above the mounting table,
Based on the captured image, the positional relationship between the first and second reference marks is detected and used as detection data,
A method for adjusting an imaging apparatus, comprising: adjusting an inclination of an optical axis of the imaging apparatus so that the detected detection data matches the stored reference data. The first and second reference marks of the detection jig are each formed by a pinhole,
The centroid position of the first and second reference marks and a positional relationship between the centroid positions are detected based on images captured by the imaging device, and the detection data is used as the detection data. Adjustment method of imaging apparatus. The first plate of the detection jig has one pinhole as a first reference mark, and the second plate has a plurality of second reference marks provided at positions shifted from the first reference mark. With a pinhole
The centroid position of the first and second reference marks and a positional relationship between the centroid positions are detected based on images captured by the imaging device, and the detection data is used as the detection data. Adjustment method of imaging apparatus. The first and second reference marks of the detection jig are measured with a three-dimensional measuring instrument and the measurement data is used as reference data. The position data of the first and second reference marks measured with the three-dimensional measuring instrument are Correlating the reference data and detection data obtained based on an image captured by the imaging device as pixel length calibration data resulting from the distance between the first and second plates, The method of adjusting an imaging apparatus according to claim 1. In the detection jig used for the adjustment method of the imaging device according to claim 1,
A first plate on which one first pinhole optically detectable is formed;
A second plate on which a plurality of optically detectable second pinholes are formed while being opposed to each other in parallel with the first plate.
The second pinhole is provided to be shifted in the surface direction of the first plate with respect to the first pinhole,
The first plate includes a plurality of first observation holes facing the second pinhole and having a diameter larger than that of the second pinhole, and the second plate includes the first pinhole and the first pinhole. A detection jig comprising a second observation hole facing and having a diameter larger than that of the first pinhole. A base substrate having a flat reference surface and a detection hole penetratingly formed in the reference surface; a first level which is provided on the reference surface and detects an inclination of the reference surface around a first axis; and the reference A second level for detecting the inclination of the reference surface around a second axis orthogonal to the first axis provided on the surface, and a horizontal adjustment mechanism for adjusting the level of the reference surface,
6. The detection jig according to claim 5, wherein the first and second plates are attached to both surfaces of the base substrate with the detection hole interposed therebetween. The horizontal adjustment mechanism includes a plurality of adjustment screws that are respectively screwed into the base substrate and that extend from the base substrate in a direction opposite to the reference surface. Detection jig.

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