Adapter lens unit

Abstract

The present invention addresses the problem of providing a technique capable of simply adding an automatic focusing function to an imaging device with a simple configuration. The solution is that an adapter lens unit (1) is connected between a camera main body unit (110) and a lens unit (120) of an existing imaging device. The control unit controls the focus position of the focus lens group of the adapter lens unit (1) on the basis of a detection signal from a ToF sensor (31) that measures the distance from the subject.

Description

Technical Field

[0001] This invention relates to adapter lens units. Background Technology

[0002] As a focusing technique in a camera device, the following technique is known: adding a range sensor to a camera device consisting of a camera body unit and a lens unit, and using the range sensor to add an autofocus function to the camera device. More specifically, as such a technique, camera systems including autofocus control based on a range sensor are known (e.g., see Patent Document 1), or industrial camera systems that include a user interface in autofocus control based on a range sensor (e.g., see Patent Document 2).

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-179601

[0006] Patent Document 2: Japanese Patent Application Publication No. 2023-173418 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, in the prior art described above, the autofocus function is achieved through the linkage between the range sensor and the camera main unit. Therefore, to achieve autofocus, the camera main unit needs to obtain a control signal from the range sensor, generate a signal to drive the focusing lens group based on that control signal, and output it to achieve focusing, etc., a complex system and adjustments. In this prior art, there is still room for exploration regarding the viewpoint of easily adding autofocus functionality to a camera device through a simplified structure.

[0009] One objective of this invention is to provide a technique that enables the easy addition of autofocus functionality to a camera device through a simple structure.

[0010] Methods for solving problems

[0011] To address the aforementioned issues, one aspect of the present invention relates to an adapter lens unit that is positioned and connected between the camera body unit and the lens unit of a camera device having a camera body unit and a lens unit detachably connected to the camera body unit. The adapter lens unit comprises: a focusing lens group movable along the optical axis of the camera body unit and the lens unit; a lens barrel having the focusing lens group and positioned between the camera body unit and the lens unit, capable of being connected to both the camera body unit and the lens unit; a distance sensor mounted in the lens barrel and measuring the distance to the subject; and a control unit built into the lens barrel, which controls the focusing position of the focusing lens group by referring to the detection signal of the distance sensor.

[0012] Invention Effects

[0013] According to one aspect of the present invention, an autofocus function can be easily added to a camera device through a simple structure. Attached Figure Description

[0014] Figure 1 This is a perspective view schematically illustrating an embodiment of the adapter lens unit according to the present invention.

[0015] Figure 2 This is a schematic left-side view of an adapter lens unit according to one embodiment of the present invention.

[0016] Figure 3 This is a schematic right-side view of an adapter lens unit according to one embodiment of the present invention.

[0017] Figure 4 This is a schematic plan view of an adapter lens unit according to one embodiment of the present invention.

[0018] Figure 5 This is a schematic bottom view of an adapter lens unit according to one embodiment of the present invention.

[0019] Figure 6 This is a perspective view schematically showing the state in which the adapter lens unit according to one embodiment of the present invention is installed in an existing camera device. Detailed Implementation

[0020] 〔summary〕

[0021] The following describes one embodiment of the present invention. The adapter lens unit of this embodiment is an adapter lens unit capable of providing an autofocus function based on a range sensor to a sensing lens.

[0022] 〔structure〕

[0023] Figures 1 to 5 This refers to the adapter lens unit in this embodiment. Figure 1 This is a schematic perspective view of the adapter lens unit according to this embodiment. Figure 2 This is a schematic left-side view of the adapter lens unit according to this embodiment. Figure 3 This is a schematic right-side view of the adapter lens unit according to this embodiment. Figure 4 This is a schematic plan view of the adapter lens unit according to this embodiment. Figure 5 This is a schematic bottom view of the adapter lens unit of this embodiment.

[0024] like Figures 1 to 5 As shown, the adapter lens unit 1 includes an adapter lens barrel 2, a ToF sensor unit 3, and a connecting cable 4.

[0025] The adapter lens barrel 2 has a focusing lens group (not shown), a drive device for driving the focusing lens group in the optical axis direction, and a control board for controlling the drive (focusing) of the focusing lens group.

[0026] A focusing lens group is a lens group in a camera device equipped with an adapter lens unit that moves along the optical axis to achieve focusing during focusing. The focusing lens group consists of one lens or a collection of two or more lenses, configured to move as a single unit during focusing. In this embodiment, the focusing lens group may consist of a single lens.

[0027] The control board is configured to control the focusing position of the focusing lens group based on the detection signal of the ToF sensor 31 in the ToF sensor unit 3 during the driving of the focusing lens group.

[0028] The focusing lens assembly and driving mechanism can employ structures known in the field of camera lenses. For example, the focusing lens assembly can consist of one or more known lenses. Examples of driving mechanisms include voice coil motors, stepper motors, and DC motors.

[0029] Furthermore, the adapter lens barrel 2 has a first mounting member 21 on its object side and a second mounting member 22 on its image plane side. The first mounting member 21, like the mounting member on the object side of the camera main unit described later, is a connecting part that can be detached and attached to the lens unit described later. The second mounting member 22, like the mounting member on the image plane side of the lens unit described later, is also a connecting part that can be detached and attached to the camera main unit described later. In this way, the adapter lens unit 1 is configured to be positioned and connected between the camera main unit and the lens unit of an imaging device having a camera main unit and a lens unit that is detachably connected to the camera main unit.

[0030] Furthermore, the adapter lens barrel 2 has a USB connector 23, a focus adjustment switch 24, and a mode switching button 25. These structures are all connected to the aforementioned control board.

[0031] USB connector 23 serves as a connection terminal for data communication and power supply between the two parties. Focus adjustment switch 24 and mode switch button 25 are both structures used for inputting signals from the user to the control board.

[0032] The ToF sensor unit 3 has a ToF sensor 31 and a mounting ring 32, and is mounted to the adapter lens barrel 2 via a connecting cable 4. The ToF sensor 31 is positioned at the object-side end of the ToF sensor unit 3, facing the object side. The ToF sensor 31 is a sensor that determines distance information by measuring the time of flight; it measures the distance to the subject by measuring the time until the light reaches the subject and returns. In this way, the ToF sensor 31 is equivalent to a rangefinder.

[0033] The mounting ring 32 is a plate-shaped and ring-shaped component that is fixed to the ToF sensor unit 3. The mounting ring 32 is fixed to the ToF sensor unit 3 with its radial direction intersecting the optical axis. The ToF sensor unit 3 has an opening diameter equal to that of the object-side opening of the lens unit described later, and is configured to be able to be mounted from the object side to the object-side end of the lens unit.

[0034] Connecting cable 4 connects ToF sensor unit 3 to adapter lens barrel 2, enabling communication between ToF sensor unit 3's ToF sensor 31 and the control board of adapter lens barrel 2. Connecting cable 4 has a slight length allowance. In this way, ToF sensor unit 3 is connected to adapter lens barrel 2 in a manner that allows adjustment of the connection length from adapter lens barrel 2.

[0035] In addition, the adapter lens unit 1 also includes a structure that allows adjustment of the connection distance with the aforementioned camera body unit. For example, the adapter lens unit 1 is configured such that a gasket is positioned between it and the second mounting member 22 in the adapter lens barrel 2. The position of the optical axis of the second mounting member 22 in the adapter lens barrel 2 is determined by the thickness and number of gaskets.

[0036] [Installation of camera equipment]

[0037] Figure 6The oblique view schematically illustrates the state of the adapter lens unit 1 mounted on an existing camera device. This camera device is configured such that the camera body unit 110, the adapter lens unit 1, and the lens unit 120 are sequentially connected from the image plane side. The camera body unit 110 is connected to the adapter lens unit 1 via a second mounting member 22, and the lens unit 120 is connected to the adapter lens unit 1 via a first mounting member 21. Furthermore, the camera body unit 110 and the lens unit 120 are connected to form the existing camera device. That is, Figure 6 The camera device shown is configured by connecting the adapter lens unit 1 between the camera body unit 110 and the lens unit 120 of an existing camera device.

[0038] The lens unit 120 has a lens mount 121 located at the image plane side end and an adapter ring 122 detachably disposed at the object-side end. Furthermore, the lens unit 120 has a lens group consisting of one or more lenses. This lens group has a front lens 123, which serves as the lens closest to the object side, at the position closest to the object side.

[0039] The lens mount 121 has the same connection function as the second mount 22 in the adapter lens unit 1, and is configured to connect detachably to the mount on the object side of the camera body unit 110 and the first mount 21 in the adapter lens unit 1. Figure 6 In the camera device, the lens mounting component 121 is connected to the first mounting component 21.

[0040] The adapter ring 122 is a component used to mount accessories such as filters to the lens unit 120. The adapter ring 122 is an annular component with an L-shaped cross-section, consisting of a cylindrical portion on the image plane side and a flange portion on the object plane side extending outwards. 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 object-side end of both the outer circumferential surface of the cylindrical portion and the inner circumferential surface of the lens unit 120, engaging with each other.

[0041] At the object-side end of the lens unit 120, a cylindrical portion of an adapter ring 122 is inserted into a mounting ring 32, with the flange abutting against the mounting ring 32. The mounting ring 32 is secured 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 it is being pressed against the object-side end. In this way, the mounting ring 32 can be mounted from the object side to the object-side end of the lens unit 120, and the ToF sensor 31 is supported by this mounting ring 32 in the imaging device.

[0042] ToF sensor 31 in Figure 6 In the camera device shown, it is supported at a specific position in the optical axis direction and radial direction of the lens unit 120.

[0043] In the optical axis direction, the ToF sensor 31 is supported at a position satisfying the following equation (1). In equation (1), L1 represents the distance along the optical axis OA from the image plane of the camera main unit 110 to the object-side lens surface in the front lens 123, and L2 represents the distance from the image plane to the detection surface of the ToF sensor 31. Furthermore, Figure 6 Line a in the diagram represents the position of the lens surface on the object side of the front lens 123 along the optical axis OA, and line b represents the position of the detection surface of the ToF sensor 31 along the optical axis OA.

[0044] 1≤L2 / L1<1.2 (1)

[0045] The ToF sensor 31 is supported in the optical axis OA direction at a position that satisfies equation (1), that is, the detection surface of the ToF sensor 31 is closer to the object side than the lens unit 120. Thus, the ToF sensor 31 can be used without being blocked by the lens unit 120. Therefore, it is preferred to use the ToF sensor 31 in its entire measurement range.

[0046] Furthermore, in the radial direction, the ToF sensor 31 is supported at a position satisfying the following equation (2). In equation (2), D1 represents the maximum distance from the optical axis OA to the outer peripheral 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. In addition, Figure 6 In the diagram, line c represents the radial position of the part with the largest outer diameter of the lens unit 120, and line d represents the center position of the detection surface of the ToF sensor 31 in the radial direction of the lens unit 120.

[0047] D2 / D1 < 1.5 (2) The ToF sensor 31 is supported in a position that satisfies equation (2), meaning that the ToF sensor 31 is supported radially at a position sufficiently close to the lens unit 120. The ToF sensor 31 is positioned as close as possible to the optical axis OA of the lens unit 120 within a range that is not obstructed by the lens unit 120. As a result, adjustments to the ToF sensor 31 and the lens unit 120 can be easily made.

[0048] Additionally, a USB cable is connected to the USB connector 23. For example, the adapter lens unit 1 can be connected to the camera body unit 110 via a USB cable, share its power supply with the camera body unit 110, share its communication device with the camera body unit 110 as needed, and share information related to its control with the camera body unit 110 as needed.

[0049] [Controls in the adapter lens unit]

[0050] [focusing]

[0051] The control board controls the focusing position of the focusing lens group by referring to the detection signal of the ToF sensor 31. For example, the control board obtains distance information from the ToF sensor 31 to the subject, obtains target position information of the focusing lens group by referring to this distance information, and drives the drive device to drive the focusing lens group to the target position. This is how it is performed. Figure 6 The focusing of the camera device in the middle.

[0052] When the adapter lens unit 1 is installed, the control board can, based on the distance information from the ToF sensor 31 and the image information on the image plane of the camera main unit 110, correct the predetermined trajectory (cam curve) of the focusing lens group moved by the drive device according to the distance information from the ToF sensor 31, thereby determining the target position. Thus, the control board controls the drive of the focusing lens group according to the distance information from the ToF sensor 31, thereby realizing focusing based on the adapter lens unit 1. In this way, focusing based on the adapter lens unit 1 is completed by the adapter lens unit 1 alone.

[0053] [Focus position correction]

[0054] If focusing is insufficient using only the aforementioned focusing control, the distance (flange distance) between the focusing lens group and the image plane is adjusted. Flange distance adjustment is achieved, for example, through coordinated operation of the adapter lens unit 1 and the camera body unit 110 in the imaging device. For instance, the user selects the flange distance adjustment mode via the mode switch button 25, adjusts the flange distance using an insert washer, and activates the focus adjustment switch 24. This causes the control board to perform the aforementioned cam curve correction. This achieves an appropriate flange distance.

[0055] Thus, according to this embodiment, by simply adjusting the flange distance or cam curve for existing sensing lenses and cameras, existing systems composed of the aforementioned lens and camera can be used. Therefore, according to this embodiment, existing imaging devices that consist only of a camera body unit 110 and a lens unit 120 and lack focusing functionality or have insufficient focusing functionality can be provided with sufficient autofocus functionality using a rangefinder sensor.

[0056] [Main Functions and Effects]

[0057] In this embodiment, a focusing lens group, a ranging sensor such as a ToF sensor 31, and a control board can be assembled into the existing sensing lens unit 120 and camera main unit 110. This allows for automatic focusing based solely on the focusing lens group within the existing camera system.

[0058] When implementing this autofocus, there is no need to change the existing camera system. Instead, by adding the adapter lens unit of this embodiment to the existing camera system, individual adjustments to the flange distance or cam curve can be easily achieved. Furthermore, the adjusted existing camera system can be used for the same sensing purpose as before the adjustment.

[0059] Furthermore, by positioning the ToF sensor 31 closer to the object side of the lens surface than the object side of the front lens 123, the entire ranging range of the ToF sensor 31 can be utilized. Therefore, it is possible to measure the distance to the object at any position within the entire photographic frame captured by the lens unit 120 and the camera body unit 110, and to focus on that position. Moreover, the ToF sensor 31 can be positioned closer to the optical axis OA of the imaging device and arranged approximately parallel to the optical axis OA. Therefore, the deviation between the photographic frame and the ranging range is reduced, making individual adjustments to the flange distance or cam profile easier.

[0060] [Other Implementation Methods]

[0061] The ToF sensor unit 3 is connected to the adapter lens barrel 2 via a connecting cable 4 with sufficient length, but this connection method can also be wireless. For example, a wireless unit can be built into the ToF sensor unit 3, and data communication between the ToF sensor 31 and the control board can be achieved through wireless communication. In this method, the degree of freedom in connecting the adapter lens barrel 2 and the ToF sensor unit 3 is further increased, which is more advantageous from the perspective of improving the versatility of the adapter lens unit 1.

[0062] [Software-related implementation methods]

[0063] The function of the control board (hereinafter also referred to as the "control unit") in this embodiment can be achieved by a program for enabling the computer to function as the control unit and for enabling the computer to function as each control module of the control unit.

[0064] In this case, the control unit, as hardware for executing the program, is a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory). By executing the program using the control device and the storage device, the functions implemented by the control unit in the above embodiments can be realized.

[0065] The aforementioned program may not be temporary and may be recorded on one or more computer-readable recording media. This 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.

[0066] Alternatively, the functions of the aforementioned control modules can also be implemented using quantum computers.

[0067] Furthermore, the control-related processes described in the above embodiments can also be executed by AI (Artificial Intelligence). In this case, the AI ​​can operate either in the aforementioned control device or in other devices (such as edge computers or cloud servers).

[0068] 〔Summarize〕

[0069] Based on the above description, it is clear that the first aspect of the present invention is an adapter lens unit (1) that is located and connected between the camera body unit and the lens unit of an imaging device having a camera body unit (110) and a lens unit (120) that is detachably connected to the camera body unit (110). The adapter lens unit includes: a focusing lens group that is movable along the optical axis (OA) of the camera body unit and the lens unit; an adapter lens barrel (2) that has the focusing lens group and is located between the camera body unit and the lens unit, and is connected to both the camera body unit and the lens unit; a ToF sensor (31) that is mounted in the adapter lens barrel and measures the distance to the subject; and a control unit that is built into the adapter lens barrel and controls the focusing position of the focusing lens group by referring to the detection signal of the rangefinder sensor. The first aspect enables an existing imaging device for sensing to be equipped with an autofocus function based on the adapter lens unit by inserting the adapter lens unit between the sensing camera body unit and the lens unit and assembling the rangefinder sensor to the existing lens unit. In this way, based on the first method, an autofocus function can be easily added to a camera device through a simple structure.

[0070] The second aspect of the present invention, in the first aspect, connects the ranging sensor to the control unit in a communicative manner, allowing for changes in the sensor's position. The second aspect is more effective from the viewpoints of increasing the flexibility of the ranging sensor's configuration and improving the versatility of the adapter lens unit.

[0071] In the third aspect of the present invention, in the first or second aspect, the range sensor is supported on a mounting member (mounting ring 32) that can be mounted from the object side to the object side end of the lens unit. The third aspect is more effective from the viewpoint that the detection surface of the range sensor can be easily positioned closer to the object side than the lens unit, and that the range sensor can be used throughout the measurement range without being obstructed by the lens unit.

[0072] In any of the first to third embodiments of the present invention, in the imaging device equipped with the adapter lens unit, the distance L1 along the optical axis from the image plane to the object-side lens surface of the lens (front lens 123) closest to the object side, and the distance L2 from the image plane to the detection surface of the range sensor, satisfy the above-described equation (1). The fourth embodiment is more effective from the viewpoints of ensuring a larger detection range of the range sensor and achieving a more compact imaging device along the optical axis, because the detection surface of the range sensor is located at a position moderately closer to the object side than the lens of the lens unit.

[0073] In any of the first to fourth embodiments of the present invention, in the imaging device equipped with the adapter lens unit, the maximum distance D1 from the optical axis to the outer peripheral surface of the lens unit and the distance D2 from the optical axis to the center of the detection surface of the range sensor satisfy the above-described equation (2). The fifth embodiment is more effective from the viewpoints of arranging the range sensor as close as possible to the optical axis of the lens unit, of easily performing adjustments to the range sensor and existing imaging devices, and of improving the detection accuracy of the range sensor.

[0074] In the sixth aspect of the present invention, in any one of the first to fifth aspects, the adapter lens unit further includes a structure capable of adjusting the connection distance with the camera body unit. The sixth aspect is more effective from the viewpoint of achieving focus position correction when the adapter lens unit is installed.

[0075] In any of the first to sixth embodiments of the present invention, the seventh embodiment of the invention further includes a connection terminal (USB connector 23) for data communication and power supply of one or both parties. In the seventh embodiment, the adapter lens unit can share power or data communication equipment with existing camera devices, thus being more efficient from the viewpoint of simplifying the structure of the adapter lens unit.

[0076] According to embodiments of the present invention, by attaching a focusing lens group to an existing camera device to which an autofocus function needs to be added or supplemented, the present invention enables the addition or supplementation of autofocus function through the attached structure. The present invention, which achieves this effect, is expected to contribute to the effective utilization of existing camera devices and to the further popularization and development of camera devices. Therefore, the present invention is expected to contribute, for example, to achieving the United Nations Sustainable Development Goals (SDGs) Goal 9 "Industry, Innovation and Infrastructure" or Goal 12 "Adopting Sustainable Consumption and Production Patterns".

[0077] This invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included within the technical scope of this invention.

[0078] Explanation of reference numerals in the attached figures

[0079] 1. Adapter lens unit

[0080] 2. Adapter lens barrel

[0081] 3 ToF sensor units

[0082] 4. Connecting cables

[0083] 21 First installation component

[0084] 22 Second installation component

[0085] 23 USB connectors

[0086] 24 Focusing adjustment switch

[0087] 25 Mode Switch Button

[0088] 31ToF sensor (range sensor)

[0089] 32 Mounting Ring

[0090] 110 Camera Main Unit

[0091] 120 lens unit

[0092] 121 Lens Mount

[0093] 122 Adapter Ring

[0094] 123 Front lens

[0095] OA optical axis

Claims

1. An adapter lens unit capable of being interposed between and connected to a camera body unit and a lens unit of an image pickup apparatus having the camera body unit and the lens unit connected to the camera body unit in a detachable manner, comprising: a focus lens group capable of moving along an optical axis of the camera body unit and the lens unit; a lens barrel having the focus lens group and interposed between the camera body unit and the lens unit, capable of being connected to both the camera body unit and the lens unit; a distance measuring sensor installed to the lens barrel and measuring a distance to a subject; and a control section built in the lens barrel and controlling a focus position of the focus lens group with reference to a detection signal of the distance measuring sensor.

2. The adapter lens unit according to claim 1, wherein the distance measuring sensor is communicably connected to the control section in a manner capable of changing a setting position.

3. The adapter lens unit according to claim 1, wherein the distance measuring sensor is supported by a mounting member capable of being mounted from an object side to an object side end portion of the lens unit.

4. The adapter lens unit according to claim 1, wherein in the image pickup apparatus in which the adapter lens unit is mounted, a distance LI on the optical axis from an image plane to an object side lens surface of a most object side lens, and a distance L2 from the image plane to a detection surface of the distance measuring sensor satisfy the following equation: 1 ≤ L2 / L1 < 1.2 (1).

5. The adapter lens unit according to claim 1, wherein in the image pickup apparatus in which the adapter lens unit is mounted, a maximum distance Dl from the optical axis to an outer peripheral surface of the lens unit, and a distance D2 from the optical axis to a center of the detection surface of the distance measuring sensor satisfy the following equation: D2 / D1 < 1.5 (2).

6. The adapter lens unit according to claim 1, further comprising a configuration capable of adjusting a connection distance to the camera body unit.

7. The adapter lens unit according to claim 1, further having a connection terminal for one or both of data communication and power supply. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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