WO2020004158A1

WO2020004158A1 - Image capture device

Info

Publication number: WO2020004158A1
Application number: PCT/JP2019/024180
Authority: WO
Inventors: 勇己大山
Original assignee: キヤノン株式会社
Priority date: 2018-06-28
Filing date: 2019-06-19
Publication date: 2020-01-02

Abstract

An image capture device comprises: an image capture element; a sensor holding member for holding the image capture element; a driving member for rotating the sensor holding member about a rotatory shaft to tilt the sensor holding member relative to a plane perpendicular to the optical axis of an image capture lens; and an optical filter insertable into and removable from the optical axis of the image capture lens. The insertion and removal direction of the optical filter is substantially parallel to the extension direction of the rotary shaft.

Description

Imaging device

The present invention relates to an imaging device such as a monitoring camera.

監視 In a surveillance camera such as a network camera, the camera unit can acquire an image by forming incident light having passed through the lens unit into an image with the image sensor.

Generally, an acquired image has a good image formation state when an object within the depth of field is photographed, and an image with a deteriorated image formation state when an object outside the depth of field is photographed.

撮影 Especially when using the aperture open, a shooting range outside the depth of field is likely to occur. Then, in a surveillance application, for example, a range where the imaging state of a subject such as a criminal's face is bad exists in the screen, and the subject cannot be recognized.

In such a case, it is conceivable to install a plurality of surveillance cameras according to the distance to the subject so that the subject enters the depth of field, but since the number of cameras increases, one camera A camera with a large depth of field is desirable.

In addition, in nighttime monitoring, there is a case where the aperture is opened in order to take in a large amount of light, so that it can be said that recognition of a subject with the aperture opened is important.

Conventionally, as a technology for increasing the depth of field with the aperture open, there is a camera technology with a tilt function that widens the depth of field range by relatively tilting the lens and the image sensor.

In addition, many surveillance cameras are equipped with an optical filter that blocks light in the infrared region in order to acquire a good image during bright daylight. The optical filter can be inserted and removed, and it is general to retract the optical filter and capture light in the infrared region at night or when monitoring a dark place where a large amount of light needs to be captured. The optical filter is usually arranged near the image sensor.

Patent Literature 1 discloses an imaging apparatus including a tilt adjustment mechanism for adjusting a tilt angle, and an optical filter insertion / extraction mechanism movable in a direction orthogonal to an optical axis and having an infrared cut filter and a dummy glass plate. An apparatus is disclosed.

Patent No. 5499581

However, both the tilting mechanism of the image sensor and the optical filter insertion / extraction mechanism need to provide a certain moving space in the optical axis direction. Therefore, in the technique described in Japanese Patent No. 5499581, it is necessary to provide a space independent of the tilt mechanism and the optical filter insertion / extraction mechanism, and there is a possibility that the size of the imaging apparatus may be increased.

The present invention provides an image pickup apparatus that can mount both a tilt mechanism of an image pickup element and an optical filter insertion / extraction mechanism without increasing the size.

In order to solve the above-described problem, one embodiment of an imaging device according to the present invention includes an imaging element, a sensor holding member that holds the imaging element, and a plane orthogonal to an optical axis of an imaging lens around a rotation axis. A driving member for rotating the sensor holding member so as to incline the sensor holding member, and an optical filter that can be inserted into and removed from the optical axis of the imaging lens, and the insertion and removal direction of the optical filter is a direction in which the rotation axis extends. And substantially parallel.

Appearance perspective view of surveillance camera in the present embodiment Exploded perspective view of an imaging device according to the present embodiment. FIG. 4 is a diagram illustrating a state of tilting of a sensor holding frame according to the present embodiment. FIG. 4 is a diagram illustrating a state of tilting of a sensor holding frame according to the present embodiment. FIG. 4 is a diagram illustrating a state of switching an optical filter according to the present embodiment. Side view around the optical filter in the present embodiment Side view around the optical filter in the present embodiment Perspective view around the optical filter in the present embodiment

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Schematic configuration of surveillance camera>
First, the configuration of the monitoring camera 500 will be described with reference to FIG. FIG. 1 is an external perspective view of the monitoring camera 500 according to the present embodiment.

The surveillance camera 500 includes a camera body (imaging device) 200 and a lens device (lens barrel) 1000 that is detachable from the camera body 200. Note that the camera body 200 and the lens device 1000 may be integrally formed. The camera body 200 has an image sensor unit 600 and the like including an image sensor and a substrate for taking an image.

The lens device 1000 has an imaging optical system such as a fixed lens, a zoom lens, and a focus lens. The fixed lens is fixed in a direction along the optical axis OA (optical axis direction). The zoom lens is moved in the optical axis direction by the zoom drive unit to perform a zooming operation (zooming). The focus lens is moved in the optical axis direction by a focus driving unit to perform a focusing operation (focusing). The light that has passed through the imaging optical system of the lens device 1000 is imaged by the imaging device.

The camera body 200 includes the base member 100, the image sensor unit 600, the optical filter unit 700, the upper case 300, and the bottom case 400. As shown in FIG. 1, the base member 100 is provided with a mount part 31 as a mounting part for mounting the lens device 1000. The mount portion 31 has three claws, and has a so-called bayonet structure that engages with and fixes the claws of the lens device 1000.

<Configuration of image sensor unit 600>
Next, a configuration of the image sensor unit 600 will be described with reference to FIGS. FIG. 2 is an exploded perspective view of the camera body 200. 3A and 3B are views showing a state where the sensor holding frame 5 is tilted. 3A shows a state in which the upper part of the sensor holding frame 5 is tilted toward the subject, and FIG. 3B shows a state in which the lower part of the sensor holding frame 5 is tilted toward the subject.

The image sensor 1 has a CMOS sensor or a CCD sensor, and photoelectrically converts a subject image (optical image) formed via the imaging optical system of the lens device 1000 to output an electric signal (image data). The image sensor 1 is soldered to the image sensor substrate 2 and attached to the sensor plate 3 with an adhesive (not shown). The image sensor substrate 2 is connected to a control board (not shown) by a cable (not shown). A sensor plate 3 on which the image pickup device 1 and the image pickup device substrate 2 are mounted is fixed to a sensor holding frame 5 as a sensor holding member by fastening screws. The sensor holding frame 5 is formed integrally with a tilt axis 5 a as a rotation axis on a substantially imaging surface of the image sensor 1, and the tilt axis 5 a is held so as to be tiltable with respect to the tilt base 4. . The tilt base 4 is a member that rotatably holds the sensor holding frame 5, and is held by the upper case 300 and the bottom case 400.

ギア A gear portion 5b is formed on the tilt shaft 5a, and the gear portion 5b meshes with a motor 6 as a driving member. The motor 6 tilts the sensor holding frame 5 with respect to the tilt base 4 by transmitting a driving force to the gear portion 5b. The tilt shaft 5a extends substantially parallel to the long side direction of the image sensor 1. By the rotation of the sensor holding frame 5, the imaging device 1 can be tilted with respect to the imaging lens via the imaging device substrate 2 and the sensor plate 3, so that it is possible to perform imaging in a deep depth of field range. become.

ワ A washer is arranged between the sensor holding frame 5 and the tilt base 4. A washer and a wave washer are arranged between the other sensor holding frame 5 and the tilt base 4. The wave washer biases the sensor holding frame 5 in order to prevent the tilt base 4 from shifting. By biasing the sensor holding frame 5 in the direction of the tilt axis 5a (the direction of the rotation axis), it is possible to prevent the image sensor from being displaced due to a difference in the installation posture of the camera body 200 or vibration.

<Configuration of Optical Filter Unit 700>
Next, a configuration of the optical filter unit 700 will be described with reference to FIGS. 2, 3, and 4. FIG. FIG. 4 is a diagram showing how the optical filters are switched.

The infrared cut filter 7 is for cutting infrared light. The glass filter 8 is inserted in the optical path when the infrared cut filter 7 is escaped from the optical path, and corrects the optical path length. When priority is given to the color reproducibility of a subject as a shooting mode, there is a so-called day mode in which an infrared cut filter 7 is inserted in an optical path to shoot an image in order to prevent infrared light from being incident on the image sensor. On the other hand, in a dark environment, shooting is performed in an environment with low illuminance. In order to improve the recognizability of the subject, the infrared cut filter 7 is removed from the optical path, and not only visible light but also infrared light is captured by the image sensor. There is also a so-called night mode in which an image is taken while the image is captured. Switching between day mode shooting and night mode shooting is possible by inserting and removing the infrared cut filter 7 in the optical path.

(4) The filter holding frame 9 holds the infrared cut filter 7 and the glass filter 8, and is guided by the guide bar 12 and the rotation restricting bar 13 in a direction perpendicular to the optical axis. The guide bar 12 and the rotation restricting bar 13 are arranged substantially parallel to the long side direction of the image sensor 1. Further, the guide bar 12 and the rotation restricting bar 13 are arranged on the subject side with respect to a plane on which the infrared cut filter 7 and the glass filter 8 move. Specifically, as shown in FIG. 5, the infrared cut filter 7 and the glass filter 8 are arranged on the subject side with respect to the plane P on which the filter moves.

The rack 10 is fixed to the filter holding frame 9 in a state where the rack 10 is urged by a rack spring 11 in the orthogonal direction and the rotation direction orthogonal to the optical axis, and is engaged with the screw portion 14 a of the stepping motor 14. Is driven in the orthogonal direction orthogonal to the optical axis. Accordingly, the filter holding frame 9 is configured to move in a direction orthogonal to the optical axis and to be inserted and removed on the optical axis. The direction in which the infrared cut filter 7 and the glass filter 8 are inserted and withdrawn is substantially parallel to the direction in which the tilt shaft 5a extends.

More specifically, as shown in FIG. 2, from the state where the infrared cut filter 7 is arranged on the optical path, the rotation of the screw portion 14a of the stepping motor 14 causes the filter holding frame 9 to move in the orthogonal direction orthogonal to the optical axis. Go to Then, as shown in FIG. 3, the glass filter 8 is placed on the optical path.

<Details when rotating the image sensor>
Next, a relationship between the optical filter unit 700 and the image sensor unit 600 when the image sensor is rotated will be described with reference to FIG.

FIGS. 5A and 5B are side views around the optical filter according to the present embodiment. 5A is a diagram illustrating a state in which the upper part of the sensor holding frame 5 is tilted toward the subject, and FIG. 5B is a diagram illustrating a state in which the lower part of the sensor holding frame 5 is tilted toward the subject.

(4) When the sensor holding frame 5 rotates about the tilt axis 5a with respect to the tilt base 4, the upper or lower part of the sensor holding frame 5 moves from the plane orthogonal to the optical axis to the subject side. Further, as shown in FIG. 4, the infrared cut filter 7 and the glass filter 8 extend the optical axis and the tilt axis 5a when the sensor holding frame 5 is turned to a turning end (for example, 15 degrees). It overlaps with the sensor holding frame 5 when viewed from a direction orthogonal to both directions.

When the filter holding frame 9 is driven in a direction orthogonal to the direction of the tilt axis 5a as in the conventional example, the filter holding frame 9 may be moved depending on the rotation angle of the image sensor 1 if the above-described structure is employed. It comes into contact with the sensor holding frame 5. Therefore, there is a case where the filter holding frame 9 cannot be inserted and removed, and a space for moving the filter holding frame 9 is required between the filter holding frame 9 and the sensor holding frame 5.

However, in the present embodiment, the filter holding frame 9 is driven in the direction of the tilt shaft 5a. This eliminates the need for a space for moving the filter holding frame 9 between the filter holding frame 9 and the sensor holding frame 5. Therefore, since the imaging device 1 can be arranged close to the filter holding frame 9, the tilting mechanism and the optical filter insertion / extraction mechanism of the imaging device 1 can be mounted without increasing the size of the imaging device.

Further, the guide bar 12 and the rotation regulating bar 13 that guide the filter holding frame 9 are closer to the imaging lens than a plane P (see FIG. 4) on which the infrared cut filter 7 and the glass filter 8 move in the optical axis direction. Are located in Thus, compared to the case where the guide bar 12 and the rotation restricting bar 13 are arranged on the plane P, the guide bar 12 and the rotation restricting bar 13 do not increase in size in the direction perpendicular to the moving direction of the filter holding frame 9 and in the direction perpendicular to both the optical axis. Therefore, it is possible to arrange the image sensor 1 closer to the filter holding frame 9.

<Modification>
FIG. 6 is a perspective view around an optical filter according to a modification of the present invention. The filter holding frame 9 has a gear portion 9a on the upper side. The gear portion 9a is formed substantially parallel to the long side direction of the image sensor 1. The motor 15 meshes with the gear 9a, and drives the filter holding frame 9 in the long side direction of the image sensor 1. With this configuration, a space on the side of the filter holding frame 9 is not required as compared with the case where the motor 14 is arranged on the side of the filter holding frame 9.

Further, in the present embodiment, the imaging element substrate 2 is held by the sensor holding frame 5 via the sensor plate 3, but may be held by the sensor holding frame 5 directly without passing through the sensor plate 3. Good.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

撮像 The imaging apparatus of the present embodiment can be applied to an application for moving an imaging element, and can be mounted on an optical device.

The present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to make the scope of the present invention public.

This application claims priority based on Japanese Patent Application No. 2018-122944 filed on Jun. 28, 2018 and Japanese Patent Application No. 2019-091387 filed on May 14, 2019, The entire contents of the description are incorporated herein.

Claims

An image sensor;
A sensor holding member that holds the image sensor,
A drive member for rotating the sensor holding member so as to be inclined with respect to a plane orthogonal to the optical axis of the imaging lens, about a rotation axis,
An optical filter that can be inserted and removed on the optical axis of the imaging lens,
The image pickup apparatus according to claim 1, wherein a direction in which the optical filter is inserted and withdrawn is substantially parallel to a direction in which the rotation axis extends.
Wherein the optical filter overlaps the sensor holding member when viewed from a direction perpendicular to both the optical axis and the direction in which the rotation axis extends, in a state where the sensor holding member is turned to the turning end. The imaging device according to claim 1.
The imaging device according to claim 1, wherein the rotation axis extends in a direction substantially parallel to a long side direction of the imaging device.
A filter holding frame that holds the optical filter, and a guide bar for guiding the movement of the filter holding frame,
4. The imaging device according to claim 1, wherein the guide bar is located closer to the imaging lens than a plane in which the optical filter is inserted and withdrawn in an optical axis direction. 5.
The imaging device according to any one of claims 1 to 4, wherein the filter holding frame holds an infrared cut filter and a dummy glass.
The imaging device according to claim 5, wherein the infrared cut filter and the dummy glass are arranged adjacent to each other in the rotation axis direction.
The imaging device according to any one of claims 1 to 5, further comprising an attachment portion to which the imaging lens can be attached.