JP2019070741A - Scheimpflug optical system, tilt mechanism unit, image capturing device - Google Patents

Abstract

To provide a Scheimpflug optical system that can have a tilting mechanism if the optical system is designed according to the specification of a C-mount lens and also can make a manufacturing device or an inspection device compact when the optical system and a camera equipped with the C-mount lens are built as image capturing devices into the manufacturing device or the inspection device, and to provide an image capturing device using the Scheimpflug optical system.SOLUTION: A Scheimpflug optical system 1 includes: an image forming lens 2; a tilt mechanism 4 for placing the image forming lens 2 in an oblique direction to an object; and a mounting part 3 with a predetermined specification to be equipped to the camera 11; and a rear converter lens 5 located between the tilt mechanism 4 and the imaging element 12 of the camera 11, the rear converter lens changing the back-focus distance of the image forming lens 2 while being attached to the camera.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a shine-proof optical system used for capturing an image in a manufacturing apparatus used for manufacturing a semiconductor, an electronic circuit board, liquid crystal, etc., and an inspection apparatus thereof, a tilt mechanism unit thereof, and an image capturing apparatus.

  In recent years, in manufacturing devices used for manufacturing semiconductors, electronic circuit boards, liquid crystals, etc., and inspection devices therefor, a wide imaging area is captured at one time as the image size of a camera used for image capturing increases and the resolution increases. Things became possible. In that case, as a matter of course, the lens used for the camera also has a low magnification, and accordingly the outer diameter and the total length of the lens increase, and the working distance to the subject also increases in proportion thereto. Therefore, a sufficient space is required to the top surface of an apparatus using such a camera, resulting in a problem that the entire apparatus becomes large.

  In addition, when there is positional restriction when capturing an image of a subject, it may not be possible to capture an image from the vertical position at the center of the subject. In this case, when the camera captures an image from an oblique direction, the subject image can be captured, but the obtained image is focused only at the central portion, and the front and back sides are out of focus. In order to solve this problem, there is known a lens with an Aori mechanism to which the principle or rule of the Shine proof described later with reference to FIGS. 1 and 2 is applied (see, for example, Patent Document 1). This is a technology conventionally applied to a lens with a bellows mechanism of a general camera using a film.

JP-A-11-190864

  For example, in order to tilt as described in Patent Document 1, it is necessary to insert a tilt mechanism between the imaging lens and the imaging device. In this respect, according to the standard of the C mount lens widely used as this type of image capturing device, since the flange back (the distance from the lens mount surface to the image pickup element) is as short as 17.526 mm, The tilt mechanism could not be inserted between the camera and the imaging device.

  It is also conceivable to use a long flange back imaging lens to insert the tilt mechanism between the imaging lens and the imaging device. In that case, it is possible to use a 35 mm digital camera interchangeable lens for ordinary household products which is a lens with a long flange back that is commercially available. Since these lenses have a long flange back, for example, 46.5 mm, it is possible to physically mount a tilt mechanism between the imaging lens and the imaging device. However, since the image forming lens itself becomes large, it becomes large as a whole even when disposed obliquely using the tilt mechanism, and a manufacturing apparatus or an inspection provided with an image capturing device using a lens that is originally intended It has not been possible to achieve compactness of the device.

  SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems, and to realize tilt using a lens of C mount standard and a camera, when incorporated as an image capture device together with a camera equipped with a C mount lens SUMMARY OF THE INVENTION An object of the present invention is to provide a Shine proof optical system and an image capturing apparatus using the same, which can be compactly configured as a manufacturing apparatus and an inspection apparatus.

  In order to solve the above-mentioned problems of the prior art and to achieve the above-mentioned purpose, the inventors have developed a novel shine proof optical system described below. That is, the present invention is a shine-proof optical system including an imaging lens, a tilt mechanism for disposing the imaging lens in an oblique direction with respect to a subject, and a mount unit of a predetermined standard for mounting on a camera. According to another aspect of the present invention, there is provided a shine-proof optical system in which a rear converter lens that changes a back focus distance of an imaging lens in a state of being mounted on a camera is disposed between the tilt mechanism and an imaging element of the camera.

  In the shine-proof optical system according to the present invention configured as described above, it is considered that a preferable solution is that the predetermined standard is a C mount or a CS mount.

  Further, according to the present invention, there is provided an image capturing apparatus having an image capturing unit in which the above-mentioned shine proof optical system is mounted on a camera.

  Further, according to the present invention, in a tilt mechanism unit mounted between an image forming lens of a predetermined standard and a camera to constitute a shineproof optical system, a lens mount unit for mounting the image forming lens, and the connecting member. A back focus distance of the imaging lens is extended by an optical axis distance of the tilt mechanism unit, which has a tilt mechanism for disposing an image lens in an oblique direction with respect to a subject, a camera mount having a configuration corresponding to the lens mount, The present invention relates to a tilt mechanism unit characterized by comprising a converter lens.

  According to the Shine proof optical system of the present invention, the principle of Shine proof is designed even if it is designed according to the standard of C mount lens or CS mount lens by extending the back focus distance of the imaging lens using a rear converter lens. It is possible to provide an alignment mechanism based on the above, and to focus on the whole screen even when the optical system is provided obliquely. In addition, when incorporated as an image capture device with a camera equipped with a C-mount lens, the camera can be arranged obliquely with respect to the subject, so a large imaging field of view can be secured, and a manufacturing apparatus or inspection device using it can be compact. It can be configured.

It is a figure for demonstrating an example of the conventional non-shine proof optical system used in order to demonstrate the principle of shine proof. It is a figure for demonstrating an example of the shine proof optical system which becomes a premise of this invention used in order to demonstrate the principle of shine proof. It is a figure which shows an example of the semiconductor device imaged with the normal camera lens of a non-Shine proof optical system. It is a figure which shows an example of the electronic circuit board imaged with the camera lens of a shine proof optical system. It is a figure which shows the state which mounted the C mount lens as an imaging lens of the non-shine proof optical system which does not have the conventional tilt mechanism unit with respect to a C mount camera. It is a figure which shows the state which mounted | wore with the C mount camera the shine proof optical system which has an imaging lens, a tilting mechanism unit, and a C mount part. In the example shown in FIG. 6, it is a figure which shows the example which inclines a tilt mechanism unit and implements an tilt. It is a figure which shows the example which comprised the rear converter lens which changes the back focus distance of an imaging lens between a tilt mechanism unit and the image sensor of a camera, and comprised the shine proof optical system of this invention. In the example shown in FIG. 8, it is a figure which shows the example which inclines a tilt mechanism unit and implements an tilt. It is a figure for demonstrating the optical effect at the time of combining a master lens and a rear converter lens.

  The Scheinproof optical system according to the present invention can mount a Scheinproof optical system having a tilt mechanism unit to a camera having a mount of a predetermined standard, for example, a camera having a C mount (inner diameter 25.4 mm, thread pitch 0.794 mm). In order to do this, it is characterized in that a rear converter lens for changing the back focus distance of the imaging lens is provided between the tilt mechanism unit and the image pickup element of the camera. Hereinafter, the principle of the shine proof which is the premise of the present invention and the shine proof optical system of the present invention will be described in order.

<On the principle of Shine Proof>
FIGS. 1 and 2 are diagrams for explaining an example of a conventional non-shine proof optical system and a shine proof optical system used to explain the principle of shine proof. As shown in FIG. 1, in a camera having an ordinary non-Shane proof optical system, the film surface and the lens main surface are attached in parallel, and the film surface and the lens main surface do not intersect. At this time, as shown in FIG. 2, the principle of the shine proof is that the film surface, the lens main surface, and the object surface intersect on the same line. Since the object plane is not parallel to the lens main surface, as shown in FIG. 2, the camera applying the principle of shine proof can simultaneously focus on one at a short distance and one at a long distance.

  FIG. 3 shows an example of an electronic circuit board imaged by a normal camera lens of the non-Shineproof optical system, and FIG. 4 shows an example of a semiconductor device imaged by the camera lens of the Scheimprein optical system. As can be seen by comparing FIGS. 3 and 4, the conventional example of FIG. 3 does not focus on the upper and lower end portions of the image, while the example taken by the camera lens of the shineproof optical system of FIG. You can see that the camera is in focus on the

<About the Shine proof optical system of the present invention>
The Shine proof optical system of the present invention will be described below with reference to FIGS. In the example shown in FIGS. 5 to 9, 1 is a shineproof optical system, 2 is a C mount lens as an imaging lens, 3 is a C mount portion on the lens side, 4 is a tilt mechanism unit for realizing an oblique mechanism, and 5 is The rear converter lens 6 is a lens with a long back focus. Further, 11 is a C-mount camera, 12 is an imaging device, and 13 is a mount on the camera side. Further, 51 is a non-shine proof optical system, 52 is a C-mount lens, and 53 is a mount on the lens side.

  FIG. 5 is a view showing a state in which a C mount lens 52 is attached to the C mount camera 11 as an imaging lens of the conventional non-shine proof optical system 51 having no tilt mechanism unit. In the example shown in FIG. 5, since the C mount lens 52 whose flange back distance is designed to be 17.526 mm is used, the image of the object is imaged on the imaging device 12 of the C mount camera 11.

  FIGS. 6 and 7 are views showing the C mount camera 11 mounted with the shineproof optical system 1 having the macro lens 6 as the imaging lens, the tilt mechanism unit 4 and the C mount portion 3. In the example shown in FIG. 6 and FIG. 7, when the tilt mechanism unit 4 is used to realize the shine proof optical system, the flange back distance becomes longer accordingly, and the C mount lens (flange back 17.526 mm) which is a general purpose standard Even if it was attached to this, it did not form an image on the imaging element 12, and it was not possible to use a C-mount lens. Therefore, it is necessary to prepare a lens 6 having a long back focus with the imaging device as an imaging lens. There are long lenses 6 for back focus that are commercially available, such as interchangeable lenses for general-purpose 35 mm digital cameras. Although it is possible to mount a tilt mechanism unit 4 that enables a physical tilt even with a flange back as long as 46.5 mm between the lens 6 and the C-mount camera 11, the lens 6 itself is large, Even if placed obliquely, the overall size becomes large, which is not compatible with the original purpose of the device being compact. In addition, although some optical manufacturers are developing and selling special optical systems that apply the principle of shine proof, they are expensive, have their own design in an integrated lens, and their range of products is limited. It has narrowed.

  In this respect, we have developed a Shine-proof optical system 1 equipped with a tilt mechanism unit 4 that can use a C-mount specification C-mount lens 2 that has a compact lens and lineup is also available at various companies, and that achieves tilt. . The C-mount lens 2 is a lens generally used in industrial applications and surveillance applications, and its flange back is as short as 17.526 mm, and the lens size is also very compact. Lineup from the long focal length (f 100 mm)). In addition, basically, it is possible to adjust the focus from all approach to infinity, and if these can be used, it is possible to cover almost all kinds of subject sizes required by the user.

  From the above, as shown in FIGS. 8 and 9, a rear converter lens 5 for changing the back focus distance of the C mount lens 2 is provided between the tilt mechanism unit 4 and the image pickup element 12 of the C mount camera 11. The shine proof optical system 1 of the present invention was constructed. The tilt mechanism itself is well known, so detailed description will be omitted, but the lens mount should be moved / slided at an arbitrary angle and fixed on a pedestal or rail keeping the distance from the imaging device 12 constant. Thus, the optical axis can be tilted without changing the distance from the image sensor 12. The rear converter lens 5 is disposed on the optical axis of the lens mount portion to configure the tilt mechanism unit 4.

FIG. 10 is a view showing a method of designing a rear converter lens when configuring a tilt mechanism unit for a master lens (for example, a C mount lens, a CS mount lens). As shown in FIG. 10A, the imaging magnification M of the master lens can be expressed by M = S ′ / S. Here, S is the distance from the front principal point of the master lens to the object point, and S ′ is the distance from the rear principal point of the master lens to the image point. On the other hand, as shown in FIG. 10B, the imaging magnification M ₂ of the rear converter lens can be expressed by M ₂ = S ₂ ′ / S ₂ . Here S ₂ is the distance from the front principal point of the rear converter lens to the object point, S 2 _'is the distance from the rear principal point of the rear converter lens to the image point. When incorporating the rear converter lens into the tilt mechanism, as shown in FIG. 10C, the image point of the master lens (flange back 17.526 mm in the case of a C mount lens, flange back in the case of a CS mount lens 12. The tilt mechanism unit 4 is incorporated so that the object point of the rear converter lens coincides with the distance of 5 mm. At this time, the total magnification M _T = M × M ₂ .

  For example, when a lens of focal length f12 and a rear converter lens of magnification of x2 are combined, f12 becomes a focal length of f24 mm which is double. If a rear converter lens of × 1.5 magnification is used, f12 will be 1.5 times f18 mm. At this time, the distance (W.D.) between the C mount lens as the imaging lens and the subject remains the original distance. The working distance does not change by using the rear converter lens. As the rear converter lens 5, a rear converter lens conventionally used widely as a CCTV lens can be applied.

  However, in the rear converter lens for a normal C mount, the imaging lens side (female) and the camera side (male) are designed at 17.526 mm according to the C mount standard. Without changing the imaging lens side (female), the camera side is designed to be as long as 46.5 mm, for example, like a 35 mm single lens reflex digital camera lens. Then, by mounting this rear converter lens between the imaging lens and the image pickup device of the camera, it becomes possible to mount a tilt mechanism unit that performs an tilt mechanism with the camera. Further, by setting the magnification of this rear converter lens to one, it is possible to maintain the angle of view of the original imaging lens and the F value without changing it.

  As the magnification of the rear converter lens, for example, 1.5 times, 2 times, 3 times or the like other than 1 time can be selected.

  In addition, although the back focus on the camera side is 46.5 mm in this example, it is also possible to give freedom depending on the size of the imaging device of the camera used. Further, it is also possible to change the imaging lens side by increasing the size of the image (2/3 ′ ′ → 1 ′ ′ → 1.1 ′ ′ → 4/3 ′ ′). By giving freedom to the basic design of these rear converter lenses, using a C mount lens as a wide imaging lens and a camera together with a tilt mechanism unit that performs tilt, it is a specification based on the principle of shine proof. It becomes possible to use.

  Although the C-mount standard has been described as an example in the above-described example, the shine-proof optical system of the present invention can also be used with another standard mount such as a CS mount according to that.

  In addition, by using the image capturing unit in which the above-described shineproof optical system of the present invention is attached to the camera as an image capturing unit of an electronic circuit board appearance inspection apparatus or manufacturing apparatus, Therefore, the device can be configured compactly while securing a large imaging field of view.

  The Shine proof optical system of the present invention can be effectively used, for example, when a C mount lens is used for a C mount camera and it is necessary to insert a tilt mechanism unit in order to carry out a tilt. .

Reference Signs List 1 shine-proof optical system 2 C-mount lens as an imaging lens 3 lens-side C-mount unit 4 tilt mechanism unit for realizing tilt 5 rear converter lens 6 long back focus lens 11 C-mount camera 12 image pickup device 13 camera-side C mount 51 Non-shine proof optical system 52 C-mount lens 53 Lens-side C mount

Claims (5)

  A shine proof optical system including an imaging lens, a tilt mechanism capable of obliquely orienting the imaging lens with respect to the subject, and a mount unit of a predetermined standard for mounting on the camera, and mounted on the camera And a rear converter lens that changes a back focus distance of an imaging lens, disposed between the tilt mechanism and an imaging element of the camera.   The shine proof optical system according to claim 1, wherein the predetermined standard is a C mount or a CS mount.   An image capturing apparatus comprising an image capturing unit in which the shine proof optical system according to claim 1 is attached to a camera. A tilt mechanism unit mounted between an imaging lens of a predetermined standard and a camera to constitute a shineproof optical system;
A lens mount unit for mounting the imaging lens, a tilt mechanism capable of obliquely orienting the imaging lens with respect to a subject, a camera mount unit having a configuration corresponding to the lens mount unit, and the tilt mechanism unit And a converter lens for extending the back focus distance of the imaging lens by an optical axis distance of the tilt mechanism unit. 5. The tilt mechanism unit according to claim 4, wherein the predetermined standard is a C mount or a CS mount.

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