JP2022014412A - Imaging apparatus - Google Patents

Abstract

To provide an imaging apparatus capable of imaging the video of an object in a plurality of modes, the configuration of the optical filter of the imaging apparatus, a filter cleaning method, and more specifically a switching mechanism for the optical filter which can be reduced in size.SOLUTION: The imaging apparatus includes an imaging element which photoelectrically converts an incident luminous flux, a lens mount for lens replacement, and a filter switching mechanism which is arranged between the lens mount and the imaging element. The filter switching mechanism includes a filter and is configured so as to rotate one end of the filter as a rotation axis or a movement rotation axis, to perform switching between a filter on state which is a state of being almost parallel with the incident surface of the imaging element in the incident luminous flux and a filter off state which is a state of being in a position out of the incident luminous flux and in a position near the incident luminous flux.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image pickup device capable of capturing an image of an object in a plurality of modes, an optical filter configuration thereof, and a filter cleaning method. The present invention relates to the cleaning method of the filter and the image pickup element used.

In recent years, video cameras and still image cameras have been expanded to include surveillance, education, medical, various measurement / analysis, and military demand, and not only visible light images (color images, black-and-white images) but also infrared light. There is a need for a multifunctional image pickup device that captures images and ultraviolet light images together, and extracts, analyzes, and compares specific wavelengths. For example, in the observation of the skin surface such as an endoscope or a dermascope for medical use, the disease state of the skin surface can be observed with a visible light image, and the disease state to the inner layer of the epidermis can be confirmed with an infrared light image. .. It is also used to acquire an ultraviolet light image and compare and analyze changes in hemoglobin in subcutaneous blood.

Also, when shooting a visible light image, an ultraviolet light cut filter, an infrared light cut filter, a P / S polarizing filter, an ND (Neutral Density) filter, a bandpass filter for a special wavelength spectrum, an optical path length correction filter, etc. are used. , A desired visible light image (color image or black-and-white image) is captured, and an image in a specific wavelength band is acquired and used for comparison and analysis of images. These image pickup devices not only obtain visual and artistic effects of images, but are also applied to grasping target images under various weather conditions, such as automatic operation, with surveillance cameras, aircraft and in-vehicle cameras, etc. The range is expanding. It is necessary to use various filters for acquiring such a visible light image, an infrared light image, an ultraviolet light image or a specific wavelength band image, processing the image, and enhancing the color effect.

In the past, the desired filter was attached to the filter replacement screw mount on the front of the lens to replace the filter. It is more convenient to have a filter inside the lens barrel to switch. Therefore, various methods for switching such a filter in the camera or the lens barrel have been proposed (Patent Document 1, Patent Document 2, Patent Document 3, etc.). In all of these methods, an infrared filter is placed parallel to the front surface of the image pickup element in the image pickup device and perpendicular to the incident optical axis, and a slide type that slides up, down, left, and right, or a rotary type that moves it in an arc shape is used. A configuration for switching between a visible light image and an infrared light image is disclosed.

Special Fair 6-52935 Gazette Japanese Unexamined Patent Publication No. 2001-75140 Japanese Patent Application Laid-Open No. 2003-259167

However, in the prior art, the filter mounting turret plate is placed and moved in parallel with the front surface of the image pickup element, perpendicular to the incident optical axis, whether it is a slide type up or down or left and right, or an arcuate rotation type. However, it has a problem that it cannot be miniaturized because it has a structure that swells greatly in the outer peripheral direction. In addition, when using the filter, it is necessary to clean it so that there is no dust or cloudiness, but in order to clean both the front and back of the filter with the conventional slide type or rotary filter switching mechanism, remove the housing or clean it when disassembling. However, it was a structure that made it difficult to maintain the filter.

In recent years, imaging devices have been required to be smaller due to the diversification of the range of use such as medical and monitoring, and many types of filters have been used due to variations in imaging purposes and the need for imaging processing. , A wide variety of commercially available filters have become available. Therefore, there is a demand for a structure in which a large number of filters can be selected according to the purpose of use while downsizing the device.

The present invention has been provided in view of the above circumstances, and an object of the present invention is to provide the following configurations of an image pickup apparatus and an optical filter thereof, and a filter cleaning method.
(1) A miniaturized optical filter switching mechanism and an image pickup device provided with the mechanism.
(2) A filter switching mechanism and a method thereof for which filter cleaning and image sensor cleaning are easy.
(3) An image pickup apparatus provided with a filter switching mechanism capable of exchanging or applying various types of filters.

In order to solve the above-mentioned problems, the image pickup device according to the present invention has an image pickup element that photoelectrically converts an incident luminous flux, a lens mount for interchangeable lenses, and a filter switching arranged between the lens mount and the image pickup element. An image pickup device having a mechanism, wherein the filter switching mechanism includes a filter, and by rotating one end of the filter as a rotation axis or a movement rotation axis, the incident surface of the image pickup element is within the incident luminous flux. It is characterized by switching between a filter-on state, which is substantially parallel to the incident light beam, and a filter-off state, which is a position deviating from the incident light flux and a position near the incident light beam.

Further, in the image pickup apparatus of the present invention, the filter-off state can be configured to be a position deviating from the incident light flux and substantially perpendicular to the incident surface of the image pickup element.

Further, in the image pickup apparatus of the present invention, the filter switching mechanism can be configured to include the filter on any or all of the upper side or the lower side, the right side or the left side of the image pickup element.

Further, in the image pickup apparatus of the present invention, the filter includes a visible light image extraction filter, an ND filter, an ultraviolet cut filter, an infrared cut filter, a near infrared extraction filter, an ultraviolet extraction filter, a polarizing filter or a shifter, and an optical path length correction filter. It can be configured to be any or a combination of absorption filters including a bandpass filter for special wavelengths.

Further, in the image pickup apparatus of the present invention, when the rotation axis or the movement rotation axis in the filter switching mechanism is located in the vicinity of the image pickup element, the filter is detachable via the lens mount opening. Can be configured in.

Further, in the image pickup apparatus of the present invention, the filter switching mechanism can be configured so that two or more of the filters can be used in the filter-on state.

Further, in the method for cleaning the filter or the image pickup element of the image pickup device of the present invention, the image pickup device includes an image pickup element that photoelectrically converts an incident light beam, a lens mount, and a filter arranged between the lens mount and the image pickup element. The filter switching mechanism has a switching mechanism, the filter switching mechanism includes a rotatable filter, a rotating shaft or a moving rotating shaft of the rotatable filter is arranged in the vicinity of an image pickup device, and the filter is rotated. By rotating as a moving axis or a moving rotation axis, a filter-on state that is substantially parallel to the image sensor in the incident light beam, and a position that is out of the incident light beam and in the vicinity of the incident light beam. The step of switching to the filter off state, the step of cleaning the filter surface from the opening of the lens mount in the filter on state, and the step of cleaning the back surface of the filter or the image sensor from the opening of the lens mount in the filter off state. It is characterized by including a step of cleaning the front surface.

In the prior art, the filter method is a slide method or a rotation switching method in which the filter turret is moved up and down and left and right on a plane perpendicular to the optical axis, whereas in the present invention, the filter is placed in a state substantially parallel to the optical axis of the incident luminous flux. Since the filter is switched to the on state or the off state by flipping it up, it can be configured compactly without swelling in the outer peripheral direction with respect to the incident optical axis. Further, since the space of the flange back length that is inevitably required is used, a space is not required for the special filter switching structure, and a miniaturized filter switching mechanism can be obtained. In addition, a filter switching mechanism that facilitates filter cleaning and cleaning of the image sensor can be obtained. Further, it is possible to configure an image pickup apparatus provided with a filter switching mechanism capable of exchanging or applying a wide variety of filters.

It is a schematic explanatory drawing which shows the aspect of Example 1 of the image pickup apparatus to which this invention was applied. It is a schematic explanatory drawing which shows the aspect of Example 2 of the image pickup apparatus to which this invention was applied. It is a schematic explanatory drawing of the removable filter configuration example applicable to this invention. It is a schematic explanatory drawing which shows the aspect of Example 3 of the image pickup apparatus to which this invention was applied. It is explanatory drawing which shows an example of the filter switching mechanism which embodied Example 3. FIG. It is a schematic explanatory drawing which looked at the inside from the opening of a lens mount. It is a schematic explanatory drawing which shows the aspect of Example 4 of the image pickup apparatus to which this invention was applied.

Hereinafter, the image pickup apparatus of this embodiment will be described in detail with reference to the drawings. It should be noted that all the drawings described in the following examples are drawn as schematic schematic views for the purpose of explaining the present invention, and the actual dimensions and shapes are not particularly limited. Further, the dimensions, materials, shapes, relative arrangements, etc. of the components are not intended to limit the technical scope of the invention to those alone unless otherwise specified.

FIG. 1 is a schematic explanatory view showing an embodiment of Example 1 of an image pickup apparatus to which the present invention is applied. The figure shows a cross-sectional view along the optical axis AA'. The image pickup apparatus has a lens mount 11 for mounting an interchangeable lens 10 and an image pickup element 12 in the housing 1, and a filter switching mechanism 13 is arranged in a space between the lens mount 11 and the image pickup element 12. There is. The lens mount 11 has a flange back length (BC in FIG. 1), which is the distance between the lens 10 and the image sensor 12, and a joining method (“screw-in type”, “spring yacht type” so as to fit the interchangeable lens 10. "And" spigot type ") and other physical dimensions are standardized. This image pickup device is assumed to be a professional video camera and a still image camera, but can be similarly applied to a consumer camera.

As described above, such a video camera and a still image camera are used in a wide variety of fields, and a wide variety of filters are applied depending on the purpose of use to obtain a desired image. As the main filter used in the present invention, an infrared ray or ultraviolet ray cut filter, an infrared ray or ultraviolet ray transmission filter, a polarizing filter, an ND (Neutral Density) filter, an optical path length correction filter, a special band pass filter and the like can be considered. These filters are mainly intended for absorption type filters.

The filter switching mechanism 13 is arranged in the space between the flange back lengths (BC) between the lens mount 11 and the image pickup element 12. In an image pickup device in which the image pickup element 12 is a single plate, a prism or a mirror for separating light flux is not required, so that the space formed by this flange back length can be effectively used. The filter switching mechanism 13 is provided with a filter mounting frame 15 having one end rotatable about a rotation shaft 14 on the upper side (upper side of FIG. 1) of the image pickup element 12 in the vicinity of the image pickup element 12. The filter 16 is arranged in the frame 15. The filter switching mechanism 13 can rotate the rotation shaft 14 manually or electrically by about 90 degrees, insert the filter 16 into the incident luminous flux, and remove the filter 16 from the incident luminous flux to put the filter off state. It has a simple structure.

In the present application, a state in which the filter filters the incident light flux to the image sensor in parallel with the front surface (incident surface) of the image sensor 12 is referred to as a filter on state or simply an on state, and the filter does not filter the incident light flux. That is, the state outside the incident luminous flux is referred to as a filter off state or simply an off state. In the embodiment of FIG. 1, the filter 16 is exemplified by a flip-up type configuration in which the filter 16 rotates about 90 degrees around the rotation shaft 14 at one end of the filter, and the front surface of the image sensor 12 (luminous flux incident) in the filter on state. It is arranged parallel to the surface) and is configured to be substantially perpendicular to the image sensor 12 in the filter off state.

However, this filter-off state is, of course, a state in which the luminous flux of the incident light is not blocked. In FIG. 1, the incident luminous flux indicates a range surrounded by dotted lines D and E. That is, the filter-off state may be placed at a position outside the incident light flux and near the incident light flux, and the rotation angle of the rotating shaft 14 is not necessarily 90 degrees. The position of the filter off state (filter flip-up angle) by the filter switching mechanism 13 is determined by the dimensions of the lens mount 11 and the image sensor 12 and the flange back length (BC) standardized for each lens mount. It is a design matter.

The filter switching mechanism 13 is provided with a filter holding frame 15 connected to a rotating shaft 14, and the filter 16 is mounted in the filter holding frame 15. Although not shown, the filter holding frame 15 and the filter 16 can be automatically or manually switched between the filter on state and the filter off state by using a motor or a spring member interlocked with the filter rotation shaft 14. These switching structures can also be realized by diverting a mirror flip-up configuration called a kick return or quick return mirror of a single-lens reflex camera. Further, the rotation axis 14 of the filter is not necessarily fixed to one axis, and if the on state and the off state of the filter are switched, it may be configured to rotate on two axes or a moving rotation axis including eccentricity. can. Further, the filter switching mechanism 13 can be configured not only to move the filter between the two set positions in the on state and the off state, but also to lock the filter in the intermediate portion between the two set positions.

When the filter 16 is set to the ON state in FIG. 1, the filter restraining members 18 and 19 integrated with the sensor support 17 are provided. The restraining members 18 and 19 position each filter in parallel with the image sensor 12, and the filter holding frame and the filter are rotated to the positions of 15'and 16', respectively. This restraining member may have any configuration as long as it is perpendicular to the optical axis AA'and can be regulated in parallel with the incident surface of the image pickup device 12, and it is not necessarily necessary to arrange the restraining member.

In the first embodiment described above, the filter switching mechanism 13 is arranged on the upper side in the vicinity of the image sensor 12 to switch between the two modes of the filter on state and the filter off state, but this arrangement location is in the vicinity of the lens mount 11. However, it may be on either the upper, lower, left or right side. There is no problem as long as an on state in which the filter is inserted in parallel with the image sensor 12 in the incident light flux and a filter off state in which the filter moves to a position where the incident light beam is not blocked are formed.

FIG. 2 shows an embodiment of the second embodiment in which the filter switching mechanism 13 is arranged on the lens mount 11 side. The difference between FIG. 2 and FIG. 1 is that the rotation shaft 14 of the filter switching mechanism 13 is arranged on the lens mount 11 side, and the same members as those in FIG. 1 are numbered the same. In the filter on state in FIG. 2, the filter 16 is arranged parallel to the front surface of the image sensor 12 so as to filter the incident luminous flux, and in the filter off state, the filter rotates and moves out of the incident luminous flux. Is. In FIG. 2, in the filter off state, it is sufficient that the filter 16 is rotated to a position outside the incident light flux and to a position in the vicinity of the incident light flux, and it is not always necessary to jump up to 90 degrees from the filter on state. When the filter switching mechanism 13 is arranged on the lens mount side in this way, the filter diameter needs to be larger than that when the filter diameter is arranged on the image sensor 12 side in FIG. There is.

The filter switching mechanism 13 in the present invention utilizes the space of the flange back length to only change the direction of the filter between the on state and the off state due to the filter switching, and the filter does not bulge in the outer peripheral direction with respect to the incident optical axis. It can be switched and the image pickup device can be miniaturized. As an application of such an embodiment, it is suitable for shooting two modes with or without various filter effects only by turning the filter on and off.

As described above, the arrangement of the filter switching mechanism 13 of the present invention utilizes the space between the lens mount 11 and the image pickup device 12. The flange back length of the interchangeable lens 10 is set between the reference surface B of the lens mount and the reference surface C of the image pickup element, and this flange back length is specified for each lens mount. For example, a C mount (industry standard) having a flange back for a small camera with a short flange back has a flange back length of 17.526 mm. Further, in various single-lens reflex type cameras, since a movable mirror is generally arranged, most lens mounts have a flange back length of 20 mm or more. In the image pickup device of the single plate image pickup element, since it is not necessary to insert the luminous flux separation optical system such as a prism in the space of the flange back length, there is sufficient room for inserting the filter switching mechanism 13 of the present invention.

Since this flange back length is specified in terms of air, when designing with a filter inserted between the lens mount reference surface B and the image sensor reference surface C, it depends on the refractive index of the inserted filter. It is necessary to make some adjustments to correspond to the air conversion. However, since the thickness of the filter is not so thick, it does not affect the arrangement of the filter switching mechanism 13, but if the influence cannot be ignored, the focus is adjusted on the lens side or a mechanism for moving the image sensor in the optical axis direction is used. You may put it in and make fine adjustments.

The size of the filter needs to cover the size of the image sensor, and the image sensor currently used in many surveillance cameras is from 1/2 inch type (length and width: 8.8 x 6.6 mm) to 1/4 inch type. The size is (vertical and horizontal: 3.6 x 2.0 mm), and the filter switching mechanism 13 of the present application can be installed in this space even when the shape of the filter mounting frame is taken into consideration.

In the conventional slide type or rotary filter switching mechanism, the surface (front surface only) on the lens mount side of the filter can be cleaned from the opening of the lens mount, but the surface (back surface) on the image sensor side. I couldn't clean it, so I had to disassemble the device, remove the filter, and clean it. However, when the rotating shaft 14 of the filter switching mechanism 13 of the present invention is arranged in the vicinity of the image pickup device 12 as in the first embodiment, the filter 16 can be easily cleaned from the opening of the lens mount 11. It becomes possible. That is, a step of switching between a filter on state and a filter off state using the filter switching mechanism according to the present invention, a step of cleaning the filter surface from the opening of the lens mount 11 in the filter on state, and a lens mount in the filter off state. By a cleaning method including a step of cleaning the back surface of the filter from the opening, both sides of the front surface of the filter when the filter is on and the rear surface of the filter when the filter is off can be cleaned from the opening of the lens mount. The fact that both sides of the filter can be easily cleaned is extremely convenient when shooting with frequent lens changes.

Further, if the filter switching mechanism of the present invention is turned off, the incident surface of the image pickup device can be directly cleaned from the opening. It is not necessary to clean the front surface of the image sensor frequently, but like cleaning the filter, the front surface of the image sensor can be easily cleaned when the interchangeable lens is frequently replaced or dust is mixed in the image sensor. Is useful.

FIG. 3 is a schematic explanatory view of a removable filter configuration example applicable to the filter switching mechanism of the present invention. If the rotation shaft 14 is arranged in the vicinity of the image pickup device 12 side of the filter switching mechanism 13 as shown in the first embodiment, the filter holding frame 15 is desired to be replaced at any time as a filter detachable type as shown in FIG. It can be configured to use a filter. When the filter switching mechanism 13 switches between the on state and the off state, the filter switching mechanism 13 rotates and moves the two setting positions by the rotation axis, but when the lens is removed, the filter switching mechanism 13 has two settings, the on state and the off state. The filter 16 can be attached and detached from the opening of the lens mount 12 while maintaining an angle in the middle of the position.

FIG. 3 shows a state in which a circular filter 16 is arranged in the filter holder 20, the filter holder 20 is inserted into the holding frame 15, and the filter 16 is attached. The filter 16 and the filter holder 20 may have any shape, whether circular or quadrangular. Further, the filter holder 20 is provided with a locking portion (recess) 21 for engaging with the filter holding frame 15 and holding the filter holder 20 in the frame. As described above, in the first embodiment of the present invention, by making the filter removable, it becomes possible to easily replace a wide variety of filters from the opening of the lens mount, and the variation of photography is widened and various. It is also possible to compare and analyze the image pickup results by the filter of the above, and to use it for image analysis and the like.

In the above-described first embodiment, the rotation shaft 14 of the filter switching mechanism 13 is arranged at one place on the upper side of the image pickup element 12, and the two modes of the filter on state and the filter off state are obtained. The position can be arranged on either the top, bottom, left or right side of the image sensor 12. FIG. 4 shows an embodiment of Example 3 in which the filter switching mechanism 40 arranges filters at two locations on the upper and lower sides of the image sensor 12 and switches between them. In FIG. 4, the same component configurations as those in FIG. 1 are numbered the same. In the third embodiment of FIG. 4, two filters are provided, one is a filter 16 in which the rotation shaft 14 is arranged on the upper side of the image pickup element 12, and the other is a filter 32 in which the rotation shaft 30 is arranged on the lower side of the image pickup element 12. ing.

In such a two-filter configuration, it is possible to obtain images in a total of three modes: a mode in which the upper filter 16 is in the on state, a mode in which the lower filter 32 is in the on state, and a mode in which both filters are in the off state. Can be done. In this case, both filters cannot be turned on at the same time, and only one of the filters must be turned on.

FIG. 5 is an example of the filter switching mechanism 40 embodying the third embodiment. In FIG. 5, the same component configurations as those in FIG. 4 are numbered the same. A (upper) filter holding frame 15 that rotates around the rotation shaft 14 is arranged on the upper side of the image sensor 12, and rotates around the rotation shaft 30 on the lower side of the image sensor 12 (lower side). Side) The filter holding frame 31 is arranged. A predetermined filter is held in each of the filter holding frames 15 and 31. A pin 51 is arranged in the middle portion of the upper filter holding frame 15 so as to engage with the groove 53 of the arm 52. Further, a pin 54 is arranged in the middle portion of the lower filter holding frame 31 so as to engage with the groove 56 of the arm 55. The arm 52 and the arm 55 are connected by a rotation axis 57 in the middle of the upper and lower filters (positions corresponding to the optical axes AA'in FIG. 5), and are arranged so as to be rotatable about the combined rotation axis 57. ing. In FIG. 5, the respective filter holding frames 15 and 31 are arranged outside the incident luminous flux (dotted lines D and E) and show the filter off state.

When the rotation pin 58 that rotates the rotation shaft 57 is rotated clockwise from the F0 position to the F1 position, the upper arm 52 moves clockwise in the arrow direction with the upper pin 51. By engaging with the upper arm groove 53, the upper filter holding frame 15 rotates about the upper rotation shaft 14 and finally moves from the filter off state position to the filter on state position parallel to the front surface of the image pickup element 12. do. The dotted line shows a state in which the upper arm 52 and the upper filter holding frame 15 are moved and the filter is turned on when the rotation pin 58 is rotated from F0 to F1. Further, when the rotation pin 58 that rotates the rotation shaft 57 is rotated counterclockwise from the F0 position to the F2 position, the lower arm 55 moves counterclockwise and lower. The lower filter holding frame 31 rotates about the lower rotation shaft 30 due to the engagement between the side pin 54 and the lower arm groove 56, and is finally parallel to the front surface of the image sensor 12 from the filter off state position. Move to the filter-on state position. With such a configuration, the upper and lower filters are in the filter off state when the rotation pin 58 is at the position of F0, and the upper filter is in the on state at the position where the movement in the F1 direction is completed, and the position where the movement in the F2 direction is completed. The lower filter is turned on. Therefore, in such a filter switching mechanism 40, it is possible to form three modes in which either the upper filter or the lower filter is on and both filters are off. The power source of the filter switching mechanism 40 may be either manual or electric, and may be switched and driven by the coupled rotary shaft 57 or the filter rotary shafts 14 and 30, or by interlocking them.

As an application example of such a two-filter switching mechanism 40, by providing a UV filter (ultraviolet light cut) in one filter and a NIR (near infrared light) cut filter in the other filter, an ultraviolet light cut image and red It is possible to acquire three modes of a high-sensitivity, wide-band visible light image by turning off the external light cut image and both filters. It is also possible to attach two filters having different light densities with an ND filter to acquire an image of each light density and an image without a filter and compare them. Further, by attaching a P polarizing filter to one filter and an S polarizing filter to the other filter, it is possible to acquire a polarized wave image of each P / S and an image without polarization in the filter off state. In addition, various shooting variations are possible by combining various filters according to the purpose of imaging.

In the above-mentioned Examples 1 to 3, the filters are arranged on the upper side and / or the lower side of the image sensor, respectively, but the filters may be arranged on either the upper or lower side or the left or right side. Alternatively, it may be placed on all sides. FIG. 6 is a view of the inside from the opening 61 of the lens mount 11, and is shown in the image sensor 12 and the filter switching mechanism 60 inside the housing 1 of the image pickup apparatus, with the upper side 62, the lower side 63, the left side 64, and the right side of each filter. It shows how all four of 65 are arranged in the filter off state. When four filters are arranged vertically and horizontally, it is possible to acquire images in each mode in which one of the filters is in the on state and in a total of five modes in which all the filters are in the off state.

As a method of utilizing such a multi-mode filter, for example, a plurality of ND filters having different light densities are arranged to acquire images having different light densities, or each wavelength band (R, G, B). ) BPF (Band Pass Filter) filter and NIR (Near Infra-Red) filter are placed for each band, and images are acquired for each band (by color), and various uses such as color analysis and measurement of the imaged object are expected. can.

FIG. 7 is a schematic explanatory view showing an embodiment of Example 4 according to the present invention, and is an explanatory diagram of a filter switching mechanism 70 in which a plurality of filters can be stacked and used. The difference between Examples 1 to 3 and Example 4 is that in Examples 1 to 3, one filter is switched on and off, whereas in Example 4, a plurality of filters are switched. It is a point that can be used as an on state by stacking. The same member configurations as those in FIG. 1 are numbered the same. In FIG. 7, the rotation shaft 14 of the filter 16 arranged on the upper side of the image sensor 12 and the rotation shaft 71 of the filter 73 arranged on the lower side are overlapped with each other when the respective filters are turned on. They are arranged so that they can be ringed. That is, the rotation shaft 71 of the lower filter 73 is arranged so as to be offset from the upper rotation shaft 14 toward the lens mount side, and the upper filter 16 and the lower filter 73 can be used independently in the ON state. , Both filters can be turned on at the same time, and the filters can be used in layers.

In such a filter configuration, a total of four modes are used: a mode in which the upper and lower filters are used independently as an on state, a mode in which both filters are overlapped and used in an on state, and a mode in which both filters are turned off. Form is possible. In this way, since the four modes can be instantly switched and acquired in the image pickup apparatus with the two filters, it is possible to analyze the object image for each of various wavelength bands. For example, when using an ND filter, a desired image is searched for while changing a large number of filters, but when ND filters with different light densities are arranged as upper and lower filters, in addition to the two images of each light density. An image having a light density in which both filters are superimposed and an image in which both filters are turned off can be obtained in four modes. When such filters are used in layers, the ND filter light density in the layers is the integrated light density. That is, when a filter having a light density of ND4 and a filter having a light density of ND8 are used, the light density is ND4xND8, and a light high density ND filter effect corresponding to the light density ND32 can be obtained.

In the filter switching mechanism 70 of the fourth embodiment, two filters arranged above and below the image sensor 12 are exemplified, but they are arranged left and right in addition to the upper and lower filters (not shown) so that the four filters are used in layers. It is also possible to configure it in. It is also possible to combine four different types of filters with each other to obtain a large number of variations of filter effects.

As described above, in the present invention, the image pickup apparatus expands in the outer peripheral direction with respect to the incident optical axis by providing a flip-up filter switching mechanism that constitutes a filter-on state and a filter-off state in the space of the flange back length of the interchangeable lens. Can be configured compactly. Further, when the rotation axis of the filter according to the present invention is provided on the image sensor side, the filter of the filter switching mechanism is detachably configured so that the filter can be easily replaced from the opening of the lens mount. The present invention has many conveniences, such as being able to provide a method that facilitates cleaning of both the front and back surfaces of a filter using such a filter switching mechanism and cleaning of the front surface of an image pickup device.

The present invention is an image pickup apparatus having a miniaturized filter switching mechanism, and is a method for facilitating cleaning on both sides of a filter and the front surface of an image pickup element. The present invention makes it possible to use a plurality of filters in combination, expanding the variation of imaging, and for industrial imaging devices such as surveillance, educational, medical, various measurement / analysis, munitions, and medical cameras. Not limited to it, it can be widely used for consumer cameras and the like.

1 Image sensor housing 10 Lens 11 Lens mount 12 Image sensor 13, 40, 60, 70 Filter switching mechanism 14, 30, 71 Rotating shaft 15, 31, 72 Filter mounting frame 16, 32, 62, 63, 64, 65 , 73 Filter 17 Image sensor support 18, 19 Filter restraint member 20 Filter holder 21 Filter locking part 61 Lens mount opening

Claims (7)

An image pickup device having an image pickup element that photoelectrically converts an incident luminous flux, a lens mount for interchangeable lenses, and a filter switching mechanism arranged between the lens mount and the image pickup element.
The filter switching mechanism includes a filter, and by rotating one end of the filter as a rotation shaft or a movement rotation shaft, the filter switching mechanism is provided.
The filter-on state, which is substantially parallel to the incident surface of the image sensor in the incident luminous flux,
An imaging device characterized by switching to a filter-off state at a position deviating from the incident luminous flux and at a position near the incident luminous flux. The image pickup apparatus according to claim 1, wherein the filter-off state is a position deviating from the incident light flux and is substantially perpendicular to the incident surface of the image pickup element. The image pickup apparatus according to claim 1 or 2, wherein the filter switching mechanism includes the filter on any or all of the upper side, the lower side, the right side, and the left side of the image pickup element. The filter includes an absorption filter including a visible light image extraction filter, an ND filter, an ultraviolet cut filter, an infrared cut filter, a near infrared extraction filter, an ultraviolet extraction filter, a polarizing filter or a shifter, an optical path length correction filter, and a bandpass filter for a special wavelength. The imaging device according to claim 1 to claim 3, wherein the image pickup device is any one of the type filters or a combination thereof. 1. Item 4. The image pickup device according to item 4. The image pickup apparatus according to claim 2 to 5, wherein the filter switching mechanism can use two or more of the filters in a filter-on state. The image pickup device has an image pickup element that photoelectrically converts an incident luminous flux, a lens mount, and a filter switching mechanism arranged between the lens mount and the image pickup element.
The filter switching mechanism includes a rotatable filter.
A rotation axis or a moving rotation axis of the rotatable filter is arranged in the vicinity of the image pickup element, and by rotating the filter as the rotation axis or the movement rotation axis, the image pickup element is included in the incident luminous flux. A step of switching between a filter-on state, which is substantially parallel to the above, and a filter-off state, which is a position outside the incident light flux and near the incident light flux.
The step of cleaning the filter surface from the opening of the lens mount in the filter-on state,
A method for cleaning a filter or an image pickup device of the image pickup apparatus, which comprises a step of cleaning the back surface of the filter or the front surface of the image pickup element from the opening of the lens mount in the filter off state.

Images