Adapter lens unit

Abstract

This technology provides a way to easily add autofocus functionality to an imaging device using a simple configuration. [Solution] The adapter lens unit (1) is connected between the camera body unit (110) and the lens unit (120) of the existing imaging device. The control unit controls the focus position of the focus lens group of the adapter lens unit (1) in response to the detection signal from the ToF sensor (31) which measures the distance to the subject.

Description

Technical Field

[0001] The present invention relates to an adapter lens unit.

Background Art

[0002] In the focusing technology of an imaging device, there is a known technology of adding a distance measuring sensor to an imaging device composed of a camera body unit and a lens unit and using it to add an autofocus function to the imaging device. More specifically, as such a technology, a camera system including autofocus control by a distance measuring sensor (see, for example, Patent Document 1), or an industrial camera system including a user interface by autofocus control by a distance measuring sensor (see, for example, Patent Document 2) is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology as described above, the autofocus function is realized by the interlocking of the distance measuring sensor and the camera body unit. Therefore, in order to express the autofocus function, the camera body unit needs to acquire and refer to a control signal from the distance measuring sensor, generate a signal for driving the focus lens group, and output it to achieve focusing, etc. A complex system and adjustment are required. Thus, in the conventional technology, there remains room for consideration from the viewpoint of simply adding an autofocus function to an imaging device with a simple configuration.

[0005] One aspect of the present invention aims to provide a technology that enables the simple addition of an autofocus function to an imaging device with a simple configuration. [Means for solving the problem]

[0006] To solve the above problems, an adapter lens unit according to one aspect of the present invention is an adapter lens unit that can be interposed and connected between a camera body unit and a lens unit of an imaging device having a camera body unit and a lens unit detachably connected thereto, and comprises: a group of focus lenses that can move along the optical axis of the camera body unit and the lens unit; a lens barrel having the group of focus lenses and interposed between the camera body unit and the lens unit, and connectable to both the camera body unit and the lens unit; a distance measuring sensor attached to the lens barrel for measuring the distance to a subject; and a control unit built into the lens barrel and controlling the focus position of the group of focus lenses by referring to the detection signal of the distance measuring sensor. [Effects of the Invention]

[0007] According to one aspect of the present invention, an autofocus function can be easily added to an imaging device with a simple configuration. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic perspective view showing an adapter lens unit according to one embodiment of the present invention. [Figure 2] This is a schematic left side view showing an adapter lens unit according to one embodiment of the present invention. [Figure 3] This is a schematic right side view showing an adapter lens unit according to one embodiment of the present invention. [Figure 4] This is a schematic plan view showing an adapter lens unit according to one embodiment of the present invention. [Figure 5] This is a schematic bottom view showing an adapter lens unit according to one embodiment of the present invention. [Figure 6] This is a schematic perspective view showing an adapter lens unit according to one embodiment of the present invention attached to an existing imaging device. [Modes for carrying out the invention]

[0009] 〔overview〕 One embodiment of the present invention is described below. The adapter lens unit of this embodiment is an adapter lens unit that can provide an autofocus function using a distance measuring sensor to a sensing lens.

[0010] 〔composition〕 The adapter lens unit of this embodiment is shown in Figures 1 to 5. Figure 1 is a schematic perspective view of the adapter lens unit of this embodiment, Figure 2 is a schematic left side view of the adapter lens unit of this embodiment, Figure 3 is a schematic right side view of the adapter lens unit of this embodiment, Figure 4 is a schematic top view of the adapter lens unit of this embodiment, and Figure 5 is a schematic bottom view of the adapter lens unit of this embodiment.

[0011] As shown in Figures 1 to 5, the adapter lens unit 1 includes an adapter lens barrel 2, a ToF sensor unit 3, and a connecting cable 4.

[0012] The adapter lens barrel 2 incorporates a group of focusing lenses (not shown), a drive device for driving the group of focusing lenses in the optical axis direction, and a control board for controlling the driving (focusing) of the group of focusing lenses.

[0013] The focusing lens group is a group of lenses that move along the optical axis to achieve focusing in an imaging device to which an adapter lens unit is attached. The focusing lens group consists of one lens or a collection of two or more lenses and is configured to move as a single unit when focusing is achieved. In this embodiment, the focusing lens group may consist of one lens.

[0014] The control board is configured to control the focus position of the focus lens group according to the detection signal of the ToF sensor 31 in the ToF sensor unit 3 in the focus lens group and driving.

[0015] The focus lens group and the driving device may adopt configurations known in the field of camera lenses. For example, the focus lens group may be composed of one or more known lenses. Also, examples of the driving device include a voice coil motor, a stepping motor, and a DC motor.

[0016] Further, the adapter lens barrel 2 has a first mount 21 on its object side and a second mount 22 on its image plane side. The first mount 21 is a detachable connection part with the lens unit described later, similar to that which the camera body unit to be described later has on the object side. The second mount 22 is a detachable connection part with the camera body unit to be described later, similar to that which the lens unit to be described later has on the image plane side. Thus, the adapter lens unit 1 is configured to be interposed and connectable between the camera body unit of an imaging device having the camera body unit and the lens unit detachably connected thereto and the lens unit.

[0017] Furthermore, the adapter lens barrel 2 has a USB connector 23, a focus adjustment switch 24, and a mode change button 25. These are all connected to the aforementioned control board.

[0018] The USB connector 23 corresponds to a connection terminal for both data communication and power supply. Both the focus adjustment switch 24 and the mode change button 25 are configurations for inputting signals from the user to the control board.

[0019] The ToF sensor unit 3 has a ToF sensor 31 and a mounting ring 32, and is attached to the adapter lens barrel 2 via a connection cable 4. The ToF sensor 31 is disposed on the object side end of the ToF sensor unit 3, facing the object side. The ToF sensor 31 is a sensor that measures distance information by measuring the flight time, and is a sensor that measures the distance to the subject by measuring the time it takes for light to reach the subject and return. Thus, the ToF sensor 31 corresponds to a distance measuring sensor.

[0020] The mounting ring 32 is a plate-shaped and ring-shaped member fixed to the ToF sensor unit 3. The mounting ring 32 is fixed to the ToF sensor unit 3 in a direction where its radial direction intersects the optical axis. The ToF sensor unit 3 has an aperture diameter equivalent to the object-side opening of the lens unit described later, and is configured to be attachable to the object side end of the lens unit from the object side.

[0021] The connection cable 4 connects the ToF sensor unit 3 and the adapter lens barrel 2, and communicatively connects the ToF sensor 31 of the ToF sensor unit 3 and the control board of the adapter lens barrel 2. The connection cable 4 has a certain length margin. Thus, the ToF sensor unit 3 is connected to the adapter lens barrel 2 such that the connection length from the adapter lens barrel 2 can be adjusted.

[0022] In addition to this, the adapter lens unit 1 further includes a structure capable of adjusting the connection distance to the camera body unit described above. For example, the adapter lens unit 1 is configured such that a washer can be interposed at the connection portion with the second mount 22 in the adapter lens barrel 2. The position of the second mount 22 in the optical axis direction in the adapter lens barrel 2 is determined by the thickness and number of washers.

[0023] 〔Attachment to the imaging device〕 Figure 6 schematically shows the adapter lens unit 1 attached to an existing imaging device. This imaging device is configured by connecting the camera body unit 110, the adapter lens unit 1, and the lens unit 120 in that order from the image plane side. The camera body unit 110 is connected to the adapter lens unit 1 via the second mount 22, and the lens unit 120 is connected to the adapter lens unit 1 via the first mount 21. The camera body unit 110 and the lens unit 120 are connected to form an existing imaging device. In other words, the imaging device shown in Figure 6 is configured by connecting the adapter lens unit 1 between the camera body unit 110 and the lens unit 120 of an existing imaging device.

[0024] The lens unit 120 has a lens mount 121 located at the image plane end and an adapter ring 122 detachably positioned at the object end. The lens unit 120 also has a lens group consisting of one or more lenses. This lens group has a front lens 123, which is the lens closest to the object, at the position closest to the object.

[0025] The lens mount 121 has a connection function similar to the second mount 22 in the adapter lens unit 1, and is configured to be detachably connected to the mount on the object side of the camera body unit 110 and the first mount 21 in the adapter lens unit 1. In the imaging device shown in Figure 6, the lens mount 121 is connected to the first mount 21.

[0026] The adapter ring 122 is a component for attaching accessories such as filters to the lens unit 120. The adapter ring 122 is a ring-shaped component with an L-shaped cross-section, consisting of a cylindrical portion on the image plane side and an outwardly extending flange portion on the object side. The outer diameter of the cylindrical portion is approximately equal to the inner diameter of the object-side end of the lens unit 120. Threads are formed on the outer circumferential surface of the cylindrical portion and on the object-side end of the inner circumferential surface of the lens unit 120, allowing them to screw into each other.

[0027] At the object-side end of the lens unit 120, the cylindrical portion of the adapter ring 122 is inserted into the mounting ring 32, with the flange portion in contact with it. The mounting ring 32 is fixed to the object-side end of the lens unit 120 by further screwing the adapter ring 122 into the lens unit 120 from the object side while the mounting ring 32 is pressed against the object-side end of the lens unit 120. In this way, the mounting ring 32 can be attached to the object-side end of the lens unit 120 from the object side, and the ToF sensor 31 is supported by such a mounting ring 32 in the imaging device.

[0028] In the imaging device shown in Figure 6, the ToF sensor 31 is supported at a specific position in the optical axis direction and radial direction of the lens unit 120.

[0029] In the optical axis direction, the ToF sensor 31 is supported at a position that satisfies the following equation (1). In equation (1), L1 represents the distance on the optical axis OA from the image plane of the camera body unit 110 to the object-side lens surface of the front lens element 123, and L2 represents the distance from the image plane to the detection surface of the ToF sensor 31. In Figure 6, line a indicates the position of the object-side lens surface of the front lens element 123 in the optical axis OA direction, and line b indicates the position of the detection surface of the ToF sensor 31 in the optical axis OA direction. 1 ≤ L2 / L1 < 1.2 (1)

[0030] The ToF sensor 31 being supported in a position that satisfies equation (1) in the optical axis direction OA, that is, the detection surface of the ToF sensor 31 being on the object side of the lens unit 120, is preferable from the viewpoint of using the ToF sensor 31 over its entire measurement range, because the ToF sensor 31 can be used without being obstructed by the lens unit 120.

[0031] Furthermore, in the radial direction, the ToF sensor 31 is supported at a position that satisfies the following equation (2). In equation (2), D1 represents the maximum distance from the optical axis OA to the outer surface of the lens unit 120, and D2 represents the distance from the optical axis OA to the center of the detection surface of the ToF sensor 31. Note that line c in Figure 6 indicates the radial position of the part of the lens unit 120 where the outer diameter is maximum, and line d indicates the center position of the detection surface of the ToF sensor 31 in the radial direction of the lens unit 120. D2 / D1<1.5 (2)

[0032] The fact that the ToF sensor 31 is supported in a position that satisfies equation (2) indicates that the ToF sensor 31 is supported in a position sufficiently close to the lens unit 120 in the radial direction. The ToF sensor 31 is positioned as close as possible to the optical axis OA of the lens unit 120, within the range where it is not obstructed by the lens unit 120. Therefore, adjustment between the ToF sensor 31 and the lens unit 120 can be easily performed.

[0033] Furthermore, a USB cable is connected to the USB connector 23. For example, the adapter lens unit 1 is connected to the camera body unit 110 by a USB cable, and can share the power supply with the camera body unit 110, share its communication device as needed, and share information related to the camera body unit 110's control as needed.

[0034] [Control in the adapter lens unit] [Focusing] The control board controls the focus position of the focus lens group by referring to the detection signal from the ToF sensor 31. For example, the control board acquires distance information from the ToF sensor 31 to the subject, refers to this distance information to acquire target position information for the focus lens group, and drives the drive device to move the focus lens group to the target position. In this way, focusing of the imaging device shown in Figure 6 is performed.

[0035] The target position can be determined when the adapter lens unit 1 is attached, by the control board modifying, as necessary, a predetermined trajectory (cam curve) in which the drive unit moves the focus lens group according to the distance information from the ToF sensor 31, based on the distance information from the ToF sensor 31 and the image information on the image plane of the camera body unit 110. Thus, focusing by the adapter lens unit 1 is achieved by the control board controlling the drive of the focus lens group according to the distance information from the ToF sensor 31. In this way, focusing by the adapter lens unit 1 is performed so that it is completed solely by the adapter lens unit 1.

[0036] [Focus correction] If focusing is insufficient with the focusing control described above, the distance between the focusing lens group and the image plane (flange back) is adjusted. Flange back adjustment is achieved, for example, by the cooperation of the adapter lens unit 1 and the camera body unit 110 in the imaging device. For example, the user selects the flange back adjustment mode using the mode switching button 25, adjusts the flange back by inserting washers, etc., and turns on the focus adjustment switch 24. As a result, the control board performs the aforementioned cam curve correction. In this way, an appropriate flange back can be achieved.

[0037] Thus, according to this embodiment, existing systems consisting of existing sensing lenses and sensing cameras can be used by simply performing individual adjustments to the flange back or cam curve. Therefore, according to this embodiment, existing imaging devices consisting only of a camera body unit 110 and a lens unit 120, which have no or insufficient focus function, can be given a sufficient autofocus function using a distance measuring sensor.

[0038] [Main effects and benefits] In this embodiment, it is possible to incorporate a focus lens group, a distance measuring sensor such as a ToF sensor 31, and a control configuration such as a control board into an existing sensing lens unit 120 and camera body unit 110. Therefore, it is possible to achieve autofocus using only the focus lens group in an existing camera system.

[0039] The implementation of this autofocus system does not require any modifications to the existing camera system. The adapter lens unit of this embodiment, added to the existing camera system, allows for easy individual adjustment of the flange back or cam curve, and the adjusted existing camera system can be used for sensing purposes in the same way as before the adjustment.

[0040] Furthermore, by positioning the ToF sensor 31 closer to the object than the object-side lens surface of the front lens element 123, the entire distance measurement range of the ToF sensor 31 can be used. Therefore, it is possible to measure the distance to a target at any position within the entire shooting screen captured by the lens unit 120 and the camera body unit 110, and to focus on that position. In addition, it becomes possible to position the ToF sensor 31 closer to the optical axis OA of the imaging device and in a direction approximately parallel to the optical axis OA. As a result, the discrepancy between the shooting screen and the distance measurement range is reduced, and individual adjustments of the flange back or cam curve become even easier.

[0041] [Other Embodiments] The ToF sensor unit 3 is connected to the adapter lens barrel 2 by a connection cable 4 with ample length, but this connection can be wireless instead of wired. For example, a wireless unit may be built into the ToF sensor unit 3, and data communication between the ToF sensor 31 and the control board may be achieved via wireless communication. This configuration is more advantageous in terms of increasing the versatility of the adapter lens unit 1 because it provides greater flexibility in connecting the adapter lens barrel 2 and the ToF sensor unit 3.

[0042] [Implementation of software] The function of the control board (hereinafter also referred to as the "control unit") in this embodiment is a program that causes a computer to function as the control unit, and can be realized by a program that causes a computer to function as each control block of the control unit.

[0043] In this case, the control unit includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., memory) as hardware for executing the program. By executing the program using this control device and storage device, each of the functions realized by the control unit in each of the above embodiments can be realized.

[0044] The above program may be recorded on one or more computer-readable recording media, not temporary ones. These recording media may or may not be provided by the control unit. In the latter case, the program may be supplied to the control unit via any wired or wireless transmission medium.

[0045] Furthermore, it is possible to implement the functions of each of the above control blocks using a quantum computer.

[0046] Furthermore, each control process described in the above embodiments may be performed by AI (Artificial Intelligence). In this case, the AI ​​may operate on the control device described above, or it may operate on another device (for example, an edge computer or a cloud server).

[0047] 〔summary〕 As is clear from the above description, the first aspect of the present invention is an adapter lens unit (1) that can be interposed and connected between a camera body unit (110) and a lens unit (120) detachably connected thereto in an imaging device, the adapter lens unit (1) having a focus lens group that can move along the optical axis (OA) of the camera body unit and the lens unit, an adapter lens barrel (2) having the focus lens group and interposed between the camera body unit and the lens unit and connectable to both the camera body unit and the lens unit, a ToF sensor (31) attached to the adapter lens barrel for measuring the distance to a subject, and a control unit built into the adapter lens barrel and controlling the focus position of the focus lens group by referring to the detection signal of the distance measuring sensor. In the first aspect, by incorporating the adapter lens unit between the sensing camera body unit and the lens unit and assembling the distance measuring sensor to the existing lens unit, it is possible to add an autofocus function by the adapter lens unit to an existing sensing imaging device. Thus, according to the first aspect, an autofocus function can be easily added to an imaging device with a simple configuration.

[0048] A second aspect of the present invention is that, in the first aspect, the distance measuring sensor is connected to the control unit in a manner that allows its installation position to be changed and in a manner that allows communication. The second aspect is even more effective in terms of increasing the degree of freedom in the placement of the distance measuring sensor and increasing the versatility of the adapter lens unit.

[0049] A third aspect of the present invention is that, in the first or second aspect, the distance measuring sensor is supported by a mounting member (mounting ring 32) that can be attached to the object-side end of the lens unit from the object side. The third aspect is even more effective in terms of easily positioning the detection surface of the distance measuring sensor on the object side of the lens unit, and in terms of enabling the distance measuring sensor to be used throughout the entire measurement range without being obstructed by the lens unit.

[0050] A fourth aspect of the present invention is that, in an imaging device to which an adapter lens unit is attached in any of the first to third aspects, the distance L1 on the optical axis from the image plane to the object-side lens surface of the lens closest to the object (front lens 123) and the distance L2 from the image plane to the detection surface of the distance measuring sensor satisfy the above-described equation (1). The fourth aspect is even more effective from the viewpoint of ensuring a wider detection range for the distance measuring sensor and from the viewpoint of realizing a more compact imaging device in the optical axis direction, since the detection surface of the distance measuring sensor is positioned appropriately closer to the object than the lens of the lens unit.

[0051] A fifth aspect of the present invention is that, in any of the first to fourth aspects, in an imaging device to which an adapter lens unit is attached, the maximum distance D1 from the optical axis to the outer surface of the lens unit and the distance D2 from the optical axis to the center of the detection surface of the distance measuring sensor satisfy the above-described equation (2). The fifth aspect is even more effective from the viewpoint of positioning the distance measuring sensor as close as possible to the optical axis of the lens unit, from the viewpoint of easily adjusting the distance measuring sensor with an existing imaging device, and from the viewpoint of improving the accuracy of detection by the distance measuring sensor.

[0052] A sixth aspect of the present invention further includes a structure in any of the first to fifth aspects in which the adapter lens unit can adjust the connection distance with the camera body unit. The sixth aspect is even more effective in terms of correcting the focus position when the adapter lens unit is attached.

[0053] A seventh aspect of the present invention is that, in any of the first to sixth aspects, the adapter lens unit further has a connection terminal (USB connector 23) for either data communication or power supply or both. The seventh aspect is even more effective in simplifying the configuration of the adapter lens unit, since the adapter lens unit can share power supply or data communication equipment with an existing imaging device.

[0054] According to embodiments of the present invention, by retrofitting a focus lens group to an existing imaging device that needs to have an autofocus function added, the present invention makes it possible to complete the addition or supplementation of the autofocus function with the retrofitted configuration. The present invention, which has such effects, is expected to contribute to the effective utilization of existing imaging devices and to the further dissemination and development of imaging devices. Therefore, the present invention is expected to contribute, for example, to the achievement of Sustainable Development Goals (SDGs) proposed by the United Nations, such as Goal 9 "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation" or Goal 12 "Ensure responsible consumption and production."

[0055] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0056] 1 Adapter Lens Unit 2 Adapter Lens Tube 3 ToF sensor units 4 connection cables 21 First Mount 22 Second Mount 23 USB connectors 24 Focus adjustment switch 25 Mode switching button 31 ToF sensor (distance measuring sensor) 32 Mounting rings 110 Camera Body Unit 120 Lens Unit 121 Lens Mount 122 Adapter Ring 123 Front lens element OA optical axis

Claims

1. An adapter lens unit that can be interposed and connected between the camera body unit and the lens unit of an imaging device having a camera body unit and a lens unit detachably connected thereto, A group of focus lenses that can move along the optical axis of the camera body unit and the lens unit, A lens barrel having the aforementioned focus lens group and interposed between the camera body unit and the lens unit, and connectable to both the camera body unit and the lens unit, A distance measuring sensor attached to the aforementioned lens barrel for measuring the distance to the subject, A control unit, which is built into the lens barrel and controls the focus position of the focus lens group by referring to the detection signal of the distance measuring sensor, An adapter lens unit having a lens.

2. The adapter lens unit according to claim 1, wherein the distance measuring sensor is connected to the control unit in a manner that allows its installation position to be changed.

3. The adapter lens unit according to claim 1, wherein the distance measuring sensor is supported by a mounting member that can be attached to the object-side end of the lens unit from the object side.

4. The adapter lens unit according to claim 1, wherein the imaging device to which the adapter lens unit is attached satisfies the following equation: the distance L1 on the optical axis from the image plane to the object-side lens surface of the lens closest to the object, and the distance L2 from the image plane to the detection surface of the distance measuring sensor. 1≦L2 / L1<1.2 (1)

5. The adapter lens unit according to claim 1, wherein the imaging device to which the adapter lens unit is attached satisfies the following equation: the maximum distance D1 from the optical axis to the outer surface of the lens unit and the distance D2 from the optical axis to the center of the detection surface of the distance measuring sensor. D2 / D1<1.5 (2)

6. The adapter lens unit according to claim 1, further comprising a structure that allows adjustment of the connection distance with the camera body unit.

7. The adapter lens unit according to claim 1, further comprising a connection terminal for data communication and / or power supply.

Images