Imaging device

Abstract

To enable optimization of the focusing drive stroke amount. [Solution] The imaging device comprises an optical system having seven lenses and an image sensor. The rear group lens, which is one lens in the optical system located on the image sensor side, is fixed to the image sensor. This technology can be applied to imaging devices, for example, which comprises an optical system having multiple lenses constituting an ultra-wide-angle lens or a telephoto lens and a BPF, and an image sensor, in which the rear group lens, which is one or more lenses in the optical system located on the image sensor side, is fixed to the object side of the image sensor.

Description

[Technical Field]

[0001] This technology relates to an imaging device, and more particularly to an imaging device that can optimize the focusing drive stroke amount. [Background technology]

[0002] In recent years, imaging devices used in mobile devices and endoscopes have adopted larger imaging sensors to improve image quality. Consequently, the optical systems of imaging devices, including one or more lenses, have become larger. For example, optical systems including six aspherical lenses (see, for example, Patent Document 1) and optical systems including four aspherical lenses and one cemented lens formed by joining two aspherical lenses (see, for example, Patent Document 2) have been devised.

[0003] In the optical system described in Patent Document 2, chromatic aberration correction can be improved by using cemented lenses. However, this optical system has a total of five lenses, four aspherical lenses and one cemented lens, and since it is difficult to process small cemented lenses, miniaturization of the optical system is difficult.

[0004] On the other hand, common focusing drive methods for imaging devices include the entire optical system drive method and the single-sensor drive method. The entire optical system drive method focuses on the subject by extending and driving the entire optical system in the optical axis direction. The single-sensor drive method focuses on the subject by retracting and driving the imaging sensor of the imaging device in the optical axis direction.

[0005] In a system that drives the entire optical system, the larger and heavier the optical system becomes, the greater the power required for the actuators to drive the entire system. Consequently, the size and power consumption of the actuators increase with the size of the optical system.

[0006] In both the overall optical system drive system and the single-sensor drive system, the image plane change is one-to-one with respect to each drive amount. Therefore, when the optical system constitutes a telephoto lens, the focusing drive stroke amount, which is the range of drive amounts required for focusing, becomes large, and the lens module in which the optical system is driven and the sensor module in which the image sensor is driven become larger. On the other hand, when the optical system constitutes a wide-angle lens, the focusing drive stroke amount becomes shorter, so the focusing accuracy is more susceptible to the limitations of the drive resolution of the actuators that drive the entire optical system and the image sensor. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2024-1404 [Patent Document 2] Japanese Patent Publication No. 2016-57562 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Therefore, optimization of the focusing drive stroke amount is desired.

[0009] This technology was developed in light of these circumstances and aims to optimize the focusing drive stroke amount. [Means for solving the problem]

[0010] One aspect of this technology is an imaging device comprising an optical system having multiple lenses and an imaging unit, wherein one or more lenses in the optical system, specifically the rear lens group, are located on the side of the imaging unit and are fixed to the imaging unit.

[0011] In one aspect of this technology, an optical system having multiple lenses and an imaging unit are provided. One or more lenses of the optical system, which are located on the side of the imaging unit, are fixed to the imaging unit.

[0012] The imaging device may be an independent device or a module incorporated into another device.

Brief Description of the Drawings

[0013] [Figure 1] It is a diagram showing a configuration example of an imaging device that is driven for focus adjustment by an overall optical system driving method or a single sensor driving method. [Figure 2] It is a diagram showing an example of the focus adjustment driving stroke amount in the imaging device of FIG. 1. [Figure 3] It is a diagram showing a configuration example of the first embodiment of an imaging device to which the present technology is applied. [Figure 4] It is an optical path diagram showing an example of the optical path of the optical system of FIG. 3. [Figure 5] It is a diagram showing an example of the specifications of the optical system of FIG. 3. [Figure 6] It is a diagram showing an example of the focus adjustment driving stroke amount in the imaging device of FIG. 3. [Figure 7] It is a diagram showing a configuration example of the second embodiment of an imaging device to which the present technology is applied. [Figure 8] It is an optical path diagram showing an example of the optical path of the optical system of FIG. 7. [Figure 9] It is a diagram showing an example of the specifications of the optical system of FIG. 7. [Figure 10] It is a diagram showing an example of the focus adjustment driving stroke amount in the imaging device of FIG. 7. [Figure 11] It is a diagram showing an outline of a configuration example of the third embodiment of an imaging device to which the present technology is applied. [Figure 12] It is a diagram for explaining the manufacturing method of the cemented lens of FIG. 11. [Figure 13] It is a diagram showing a first external configuration example of the cemented lens array. [Figure 14] It is a diagram showing a second external configuration example of the cemented lens array. [Figure 15] It is a diagram showing an external configuration example of the cemented lens of FIG. 11. [Figure 16] It is a diagram for explaining a cemented lens in which lenses individually manufactured are adhered with an adhesive. [Figure 17] This is the first diagram illustrating a manufacturing method for individually producing lenses. [Figure 18] This is the second diagram illustrating the manufacturing method for individually producing lenses. [Figure 19] This is the third diagram illustrating the manufacturing method for individually producing lenses. [Figure 20] This is a flowchart illustrating a first example of the method for fabricating the rear lens group shown in Figure 11. [Figure 21] This is a flowchart illustrating a second example of the method for fabricating the rear lens group shown in Figure 11. [Figure 22] This is a flowchart illustrating a third example of the method for fabricating the rear lens group shown in Figure 11. [Figure 23] Figure 11 is an optical path diagram showing the optical path of the first design example of the optical system. [Figure 24] This figure shows the specifications of the first design example of the optical system in Figure 11. [Figure 25] This figure shows the setting data for the first design example of the optical system shown in Figure 11. [Figure 26] This figure shows the aspherical data for each surface in the first design example of the optical system shown in Figure 11. [Figure 27] This is an optical path diagram showing the optical path of the second design example of the optical system in Figure 11. [Figure 28] This figure shows the specifications of the second design example of the optical system in Figure 11. [Figure 29] This figure shows the setting data for the second design example of the optical system in Figure 11. [Figure 30] This figure shows the aspherical data for each surface in the second design example of the optical system shown in Figure 11. [Figure 31] Figure 11 illustrates the effect of the cemented lens. [Figure 32] This figure shows an example configuration of a fourth embodiment of an imaging device to which this technology is applied. [Figure 33] This figure shows an example of the specifications for the optical system shown in Figure 32. [Figure 34] Figure 32 shows an example of the focusing drive stroke amount in the imaging device. [Figure 35] This figure shows an example configuration of a fifth embodiment of an imaging device to which this technology is applied. [Figure 36] This figure shows an example of the specifications for the optical system shown in Figure 35. [Figure 37] Figure 35 shows an example of the focusing drive stroke amount in the imaging device. [Figure 38] This diagram illustrates an example of how to use the imaging device. [Figure 39] This block diagram shows an example configuration of a camera as an electronic device to which this technology is applied. [Figure 40] This block diagram shows an example of a schematic configuration of a vehicle control system. [Figure 41] This is an explanatory diagram showing an example of the installation location of the imaging unit. [Modes for carrying out the invention]

[0014] The following describes the embodiments for implementing this technology. The description will be given in the following order. 1. Imaging device that is driven to focus using either an overall optical system drive method or a sensor-only drive method. 2. First Embodiment (Imaging device having an ultra-wide-angle lens without a cemented lens) 3. Second Embodiment (Imaging device having a telephoto lens without a cemented lens) 4. Third Embodiment (Imaging device having an ultra-wide-angle lens including a cemented lens in the rear lens group) 5. Fourth Embodiment (Imaging device having an ultra-wide-angle lens including a cemented lens in the front lens group) 6. Fifth Embodiment (Imaging device having a telephoto lens with a cemented lens in the rear lens group) 7. Examples of using the imaging device 8. Examples of application to electronic devices 9. Examples of applications to mobile devices

[0015] In the drawings referenced in the following explanation, identical or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic, and the relationship between thickness and planar dimensions, the ratio of the thickness of each layer, etc., may differ from the actual dimensions. Furthermore, there may be parts where the dimensional relationships and ratios differ between drawings.

[0016] Furthermore, the definitions of directions such as up and down in the following explanation are merely for explanatory convenience and do not limit the technical concept of this disclosure. For example, if an object is rotated 90° and observed, up and down will be converted to left and right and read accordingly, and if it is rotated 180° and observed, up and down will be inverted and read accordingly.

[0017] <1. Imaging device that focuses using either an overall optical system drive method or a sensor-only drive method> <Example configuration of an imaging device that focuses using either an overall optical system drive method or a sensor-only drive method> Figure 1 shows an example configuration of an imaging device that is driven to focus using either an overall optical system drive method or a single-sensor drive method.

[0018] The imaging device 10 shown in Figure 1 comprises an optical system 11, a holder 12, and an imaging sensor 13.

[0019] The optical system 11 consists of five lenses 21-25 and a Band Pass Filter (BPF) 26. The holder 12 fixes the lenses 21-25 and the BPF 26 in predetermined positions so that they are arranged in the order of lenses 21, 22, 23, 24, 25, and BPF 26 from the object side (subject side). Light incident on the imaging device 10 from the subject is focused through the optical system 11 and irradiated onto the imaging sensor 13. The imaging sensor 13 converts the irradiated light into an electrical signal and generates an imaging signal.

[0020] When the imaging device 10, configured as described above, is driven to focus using the entire optical system drive method, the entire optical system 11 is extended in the direction of the optical axis. That is, the entire optical system 11 moves toward the object. On the other hand, when the imaging device 10 is driven to focus using the sensor-only drive method, the imaging sensor 13 is retracted in the direction of the optical axis. That is, the imaging sensor 13 moves toward the opposite side from the optical system 11.

[0021] <Example of focusing drive stroke amount> Figure 2 shows an example of the focusing drive stroke amount in the imaging device 10 shown in Figure 1.

[0022] In the example shown in Figure 2, the diagonal length of the image sensor 13 is 10 mm. In Figure 2, the horizontal axis represents the shooting distance [m], and the vertical axis represents the total extension amount [μm] of the optical system 11 from the infinity focus position when focusing is performed using the overall optical system drive method. The infinity focus position is the focus position when the shooting distance is infinity.

[0023] When the optical system 11 constitutes a telephoto lens with, for example, a field of view of 20 degrees, the focusing drive stroke amount St, which is the range from the extension amount when the shooting distance is 10 m to the extension amount when the shooting distance is very close to 0 m, is long, as shown by the solid line in Figure 2. Consequently, the imaging device 10 becomes larger.

[0024] On the other hand, when the optical system 11 constitutes an ultra-wide-angle lens with a field of view of, for example, 120 degrees, the focusing drive stroke amount Sw, which is the range from the extension amount when the shooting distance is 10m to the extension amount when the shooting distance is very close to 0m, is short, as shown by the dotted line in Figure 2. Therefore, in this case, the focusing accuracy is easily limited by the drive resolution of the actuator that drives the entire optical system 11. Consequently, if the drive resolution of the actuator is large, that is, if the pitch that can drive the entire optical system 11 is large, it may not be possible to sufficiently improve the focusing accuracy.

[0025] Although not shown in the diagram, the focusing drive stroke amount in the sensor-only driving method is similar to the focusing drive stroke amount in the entire optical system driving method: it is longer when the optical system 11 constitutes a telephoto lens and shorter when it constitutes a wide-angle lens.

[0026] <2. First Embodiment> <Example of imaging device configuration> Figure 3 shows an example configuration of a first embodiment of an imaging device to which this technology is applied.

[0027] In the following explanation, we will use the example of an ultra-wide-angle lens composed of a predetermined number of lenses, but this technology can be applied to any number of ultra-wide-angle lenses.

[0028] The imaging device 100 in Figure 3 consists of an optical system 111, a holder 112, and an image sensor 113. In the imaging device 100, the seven lenses 121 to 127 that constitute the ultra-wide-angle lens, which are included in the optical system 111, are divided into a front lens group and a rear lens group, and the rear lens group is fixed to the image sensor 113.

[0029] Specifically, the optical system 111 of the imaging device 100 is composed of seven lenses 121-127 and a BPF 128. The seven lenses 121-127 are divided into a front lens group consisting of six lenses 121-126 positioned on the object side, and a rear lens group consisting of one lens 127 positioned closest to the image (on the imaging sensor 113 side).

[0030] The holder 112 fixes lenses 121-125 and BPF128 in predetermined positions so that they are arranged in the order of lenses 121, 122, 123, 124, 125, 126, and BPF128 from the object side.

[0031] A lens section 131, including a single lens 127 which is a rear lens group, is directly fixed to the object side of the image sensor 113 (imaging section). The lens section 131 consists of the lens 127, which is the optically effective part, and a lens holding section 141 that fixes this lens 127 to the image sensor 113. The lens holding section 141 is joined to the imaging surface 113a, which is the object side surface of the image sensor 113. At least one surface of the lens holding section 141 is flat. An air layer is formed between the lens 127 and the image sensor 113.

[0032] The lens 127 and the lens holder 141 may be formed as a single unit or as separate parts. When the lens 127 and the lens holder 141 are formed as a single unit, the image sensor 113 to which the rear lens group is fixed can be made smaller compared to when they are formed as separate parts. The lens 127 and the lens holder 141 are formed by molding resin material or glass.

[0033] Light incident on the imaging device 100 from the subject is focused via the optical system 111 and irradiated onto the imaging surface 113a of the imaging sensor 113. The imaging sensor 113 converts the light irradiated onto the imaging surface 113a into an electrical signal and generates an imaging signal.

[0034] The imaging device 100, configured as described above, achieves focus by driving either the front section 151, which consists of a front lens group fixed by a holder 112 and a BPF 128, or the rear section 152, which consists of an image sensor 113 to which a rear lens group is fixed. Specifically, the front section 151 moves (extends) toward the object along the optical axis, or the rear section 152 moves (retracts) toward the opposite side of the optical axis from the front section 151. Hereinafter, the method of achieving focus by driving the front section including the front lens group will be referred to as the front-stage drive method, and the method of achieving focus by driving the rear section including the image sensor to which the rear lens group is fixed will be referred to as the rear-stage drive method.

[0035] In the example shown in Figure 3, the front lens group is composed of lenses 121 to 126, and the rear lens group is composed of lens 127. However, the method of dividing the front and rear lens groups is arbitrary. For example, the front lens group can be composed of L lenses (where L is an integer between 1 and 6) in order from the object side, and the rear lens group can be composed of (7-L) lenses in order from the image side. If the rear lens group has multiple lenses, all of the multiple lenses constituting the rear lens group are fixed to the image sensor 113 by the lens holder.

[0036] <Example of an optical path in an optical system> Figure 4 is an optical path diagram showing an example of the optical path of optical system 111 in Figure 3.

[0037] Although not shown in Figure 3, as shown in Figure 4, the optical system 111 also has an aperture diaphragm 161 positioned between lens 122 and lens 123.

[0038] As shown in Figure 4, when the drive amount is 0, light incident on the imaging device 100 from infinity is focused on the imaging plane 113a via lenses 121, 122, aperture diaphragm 161, lenses 123-126, BPF 128, and lens 127, and an image is formed.

[0039] <Example of optical system specifications> Figure 5 shows an example of the specifications of the optical system 111.

[0040] In the example shown in Figure 5, the focal length of optical system 111 is 2.37 mm, the Fno (F-number) is 2.26, and the image height is 3.68 mm. The angle of view of optical system 111 is 120 deg, the total length TL is 7.0 mm, and the lateral magnification (power) β of the rear lens group is 0.894. The value d / TL, obtained by dividing the distance d from the frontmost surface (the object-side surface) of the rear lens group of optical system 111 to the image sensor by the total length TL, is 0.12.

[0041] Note that each value in FIG. 5 is an example and can be any value. It is desirable that the lateral magnification β of the optical system 111 satisfies 0.89 < β < 1. It is desirable that d / TL of the optical system 111 satisfies 0 < d / TL < 0.5.

[0042] <Example of focusing drive stroke amount> FIG. 6 is a diagram showing an example of the focusing drive stroke amount in the imaging device 100.

[0043] In FIG. 6, the horizontal axis represents the shooting distance [m], and the vertical axis represents the amount of extension from the infinite focus position [μm]. This is the same in FIGS. 10 and 34 described later.

[0044] The solid line in FIG. 6 represents the amount of extension of the front stage portion 151 corresponding to each shooting distance when the imaging device 100 performs focusing drive in the front stage drive method. The dotted line in FIG. 6 represents the amount of extension of the entire optical system 111 corresponding to each shooting distance when the imaging device having the optical system 111 performs focusing drive in the entire optical system drive method.

[0045] As shown by the solid line in FIG. 6, in the front stage drive method, the focusing drive stroke amount Sw1, which is in the range from the amount of extension when the shooting distance is 100 m to the amount of extension when the shooting distance is the closest distance close to 0.10 m, is about 28.7 μm.

[0046] On the other hand, as shown by the dotted line in FIG. 6, in the entire optical system drive method, the focusing drive stroke amount Sw2, which is in the range from the amount of extension when the shooting distance is 100 m to the amount of extension when the shooting distance is the closest distance close to 0.10 m, is about 23 μm. Therefore, the focusing drive stroke amount Sw1 is about 1.25 times (= 28.7 / 23) of the focusing drive stroke amount Sw2. That is, the focusing drive stroke amount Sw1 is enlarged by about 25% with respect to the focusing drive stroke amount Sw2.

[0047] As described above, by performing focusing drive using a pre-stage drive method, the imaging device 100 can achieve a longer focusing drive stroke compared to when focusing drive is performed using an overall optical system drive method. Therefore, the focusing accuracy is less constrained by the drive resolution of the actuator that drives the pre-stage 151. Thus, even when the drive resolution of the actuator is large, i.e., when the pitch that can drive the pre-stage 151 is large, it is possible to sufficiently improve the focusing accuracy.

[0048] Although not shown in the diagram, the focusing drive stroke in the downstream drive system can also be made longer than when focusing is performed using the entire optical system drive system, similar to the focusing drive stroke in the upstream drive system.

[0049] As described above, the imaging device 100 comprises an optical system 111 having lenses 121 to 127 and an image sensor 113. The lens 127, which is located on the image side of the optical system 111, is fixed to the image sensor 113. Therefore, the imaging device 100 can perform focusing drive using, for example, a pre-drive system or a post-drive system. As a result, the focusing drive stroke amount can be optimized.

[0050] For example, in the imaging device 100, the lens 127 has a lateral magnification β satisfying 0.89 < β < 1, which allows the focusing drive stroke to be expanded to 1 to 1.25 times that of the overall optical system drive method. As a result, the focusing accuracy of the imaging device 100, in which the optical system 111 constitutes an ultra-wide-angle lens, can be significantly improved.

[0051] <3. Second Embodiment> <Example of imaging device configuration> Figure 7 shows an example configuration of a second embodiment of an imaging device to which this technology is applied.

[0052] In the following explanation, we will use the example of a telephoto lens composed of a predetermined number of lenses and one prism, but this technology can be applied to any number of lenses and prisms used in a telephoto lens.

[0053] The imaging device 200 in Figure 7 consists of an optical system 211, a holder 212, and an image sensor 213. In the imaging device 200, the four lenses 221-224 and one prism 225 that constitute a telephoto lens, which are included in the optical system 211, are divided into a front lens group and a rear lens group, and the rear lens group is fixed to the image sensor 213.

[0054] Specifically, the optical system 211 of the imaging device 200 consists of four lenses 221-224, a prism 225, and a BPF 226. The four lenses 221-224 and the prism 225 are divided into a front lens group consisting of three lenses 221-223 and the prism 225 on the object side, and a rear lens group consisting of the single lens 224 on the image side.

[0055] The holder 212 fixes the lenses 221-223, prism 225, and BPF 226 in predetermined positions so that they are arranged in order from the object side, from the object side.

[0056] A lens section 231, including a single lens 224 which is a rear lens group, is directly fixed to the object side of the image sensor 213. The lens section 231 consists of the lens 224, which is the optically effective part, and a lens holding section 241 that fixes the lens 224 to the image sensor 213. The lens holding section 241 is joined to the imaging surface 213a, which is the object side surface of the image sensor 213. At least one surface of the lens holding section 241 is flat. An air layer is formed between the lens 224 and the image sensor 213.

[0057] The lens 224 and lens holder 241 may be formed as an integrated unit, similar to the lens 127 and lens holder 141 in Figure 3, or they may be formed as separate parts. The lens 224 and lens holder 241 are formed by molding resin or glass.

[0058] Light incident on the imaging device 200 from the subject is focused via the optical system 211 and irradiated onto the imaging surface 213a of the imaging sensor 213. The imaging sensor 213 converts the light irradiated onto the imaging surface 213a into an electrical signal and generates an imaging signal.

[0059] The imaging device 200 configured as described above achieves focusing by a front-stage drive system that drives a front-stage section 251 consisting of a front lens group fixed by a holder 212 and a BPF 226. Alternatively, the imaging device 200 achieves focusing by a rear-stage drive system that drives a rear-stage section 252 consisting of an image sensor 213 to which a rear lens group is fixed.

[0060] In the example shown in Figure 7, the front lens group consists of lenses 221-223 and prism 225, and the rear lens group consists of lens 224. However, the method of dividing the front and rear lens groups is arbitrary.

[0061] <Example of an optical path in an optical system> Figure 8 is an optical path diagram showing an example of the optical path of the optical system 211 in Figure 7.

[0062] As shown in Figure 8, when the drive amount is 0, light incident on the imaging device 200 from infinity is focused on the imaging surface 213a via lenses 221-223, prisms 225 and BPF 226, and lens 224, and an image is formed.

[0063] <Example of optical system specifications> Figure 9 shows an example of the specifications of the optical system 211.

[0064] In the example shown in Figure 9, the focal length of optical system 211 is 15.6 mm, the FNo is 2.8, and the image height is 2.94 mm. The field of view of optical system 211 is 21 degrees, and the total length TL is 20 mm. The lateral magnification β of the rear lens group of optical system 211 is 1.23, and the value d / TL is 0.06.

[0065] Note that each value in FIG. 9 is an example and can be any value. It is desirable that the lateral magnification β of the rear group lens of the optical system 211 satisfies 1 < β < 1.23. It is desirable that d / TL of the optical system 211 satisfies 0 < d / TL < 0.5.

[0066] <Example of focusing drive stroke amount> FIG. 10 is a diagram showing an example of the focusing drive stroke amount in the imaging device 200.

[0067] The solid line in FIG. 10 represents the extension amount of the front stage portion 251 corresponding to each shooting distance when the imaging device 200 performs focusing drive in the front stage drive method. The dotted line in FIG. 10 represents the extension amount of the entire optical system 211 corresponding to each shooting distance when the imaging device having the optical system 211 performs focusing drive in the entire optical system drive method.

[0068] As shown by the solid line in FIG. 10, in the front stage drive method, the focusing drive stroke amount St1, which ranges from the extension amount when the shooting distance is 100 m to the extension amount when the shooting distance is the closest distance close to 0.10 m, is approximately 646.8 μm.

[0069] On the other hand, as shown by the dotted line in FIG. 10, in the entire optical system drive method, the focusing drive stroke amount St2, which ranges from the extension amount when the shooting distance is 100 m to the extension amount when the shooting distance is the closest distance close to 0.10 m, is approximately 980 μm. Therefore, the focusing drive stroke amount St1 is approximately 0.66 times (= 646.8 / 980) of the focusing drive stroke amount St2. That is, the focusing drive stroke amount St1 is reduced by approximately 30% with respect to the focusing drive stroke amount St2.

[0070] As described above, by performing focusing drive in the front stage drive method, the imaging device 200 can shorten the focusing drive stroke amount compared to the case of performing focusing drive in the entire optical system drive method. Therefore, the imaging device 200 can be miniaturized.

[0071] Although not shown in the diagram, the focusing drive stroke in the downstream drive system can also be made shorter than when focusing is performed using the entire optical system drive system, similar to the focusing drive stroke in the upstream drive system.

[0072] As described above, the imaging device 200 comprises an optical system 211 having lenses 221-224 and a prism 225, and an image sensor 213. The lens 224, which is located on the image side (image sensor 213 side) of the optical system 211, is fixed to the image sensor 213. Therefore, the imaging device 200 can perform focusing drive using, for example, a pre-drive system or a post-drive system. As a result, the focusing drive stroke amount can be optimized.

[0073] For example, in the imaging device 200, the lens 224 has a lateral magnification β satisfying 1 < β < 1.23, which allows the focusing drive stroke to be reduced to 0.66 to 1 times compared to the overall optical system drive method. As a result, the imaging device 200, in which the optical system 211 constitutes a telephoto lens, can be miniaturized.

[0074] <4. Third Embodiment> <Example of imaging device configuration> Figure 11 is a schematic diagram showing an example configuration of a third embodiment of an imaging device to which this technology is applied.

[0075] The imaging device 300 in Figure 11 consists of an optical system 311 and an image sensor 312. In the imaging device 300, the three aspherical lenses that constitute the ultra-wide-angle lens, which are included in the optical system 311, are divided into a front lens group and a rear lens group, and the rear lens group is fixed to the image sensor 312.

[0076] Specifically, the optical system 311 of the imaging device 300 includes three aspherical lenses, lens 321 (first lens), lens 322 (second lens), and a cemented lens 323 and a BPF 324. The lenses 321, lens 322, and cemented lens 323, which are arranged in order from the object side toward the image plane, are divided into a front lens group consisting of the lens 321 closest to the object, and a rear lens group consisting of the lens 322 and cemented lens 323 on the image side. The cemented lens 323 is formed by bonding lens 323-2 to the object side of lens 323-1.

[0077] A lens section 331, which includes a rear lens group lens 322 and a cemented lens 323 as its optically effective part, is directly fixed to the object side of the image sensor 312. The lens section 331 consists of a cemented lens 323 formed by stacking lenses 322 and a lens holding section 331a that fixes the cemented lens 323 to the image sensor 312. The lens holding section 331a is bonded to the imaging surface 312a, which is the object side surface of the image sensor 312, and fixes the cemented lens 323 and BPF 324 so that they are arranged in that order from the object side. At least one surface of the lens holding section 331a is flat. An air layer is formed between each of the lens 322, cemented lens 323, BPF 324, and image sensor 312.

[0078] In the following description, the cemented lens 323, in which the lens 322 is stacked, and the lens holder 331a are assumed to be formed as separate parts, but they may also be formed as a single unit. When the cemented lens 323, in which the lens 322 is stacked, and the lens holder 331a are formed as a single unit, the image sensor 312 to which the rear lens group and BPF 324 are fixed can be made smaller compared to when they are formed as separate parts.

[0079] Light incident on the imaging device 300 from the subject is focused via the optical system 311 and irradiated onto the imaging surface 312a of the imaging sensor 312. The imaging sensor 312 converts the light irradiated onto the imaging surface 312a into an electrical signal and generates an imaging signal.

[0080] The imaging device 300 configured as described above achieves focus by either a front-stage drive system that drives a front-stage section 341 consisting of a front group of lenses, or by a rear-stage drive system that drives a rear-stage section 342 consisting of an imaging sensor 312 to which a rear group of lenses and a BPF 324 are fixed.

[0081] In the example shown in Figure 11, the front lens group is composed of lens 321, and the rear lens group is composed of lens 322 and cemented lens 323. However, the method of dividing the front and rear lens groups is arbitrary.

[0082] <Explanation of manufacturing method for bonded lenses> Figure 12 is a diagram illustrating the manufacturing method of the cemented lens 323 shown in Figure 11.

[0083] As shown in Figure 12, first, a lens array 351-1 is fabricated in which multiple lenses 323-1 of the bonded lens 323 are formed. Next, a lens array 351-2 is fabricated in which multiple lenses 323-2 are formed by integrating with this lens array 351-1 without including an adhesive layer at the bonding interface. The bonded lens array 351, fabricated by integrating lens arrays 351-1 and 351-2 in this manner, is cut and separated into multiple bonded lenses 323.

[0084] <Example of the first external configuration of a bonded lens array> Figure 13 shows a first example of the external configuration of the cemented lens array 351 shown in Figure 12.

[0085] Figure 13A is a perspective view of the cemented lens array 351, and Figures 13B and C are top views of lens arrays 351-2 and 351-1, respectively.

[0086] In the example shown in Figure 13, the upper surfaces of lens arrays 351-1 and 351-2 are circular with a diameter of φ150 mm (6 inches). Therefore, the upper surface of cemented lens array 351 is also circular with a diameter of φ150 mm. Approximately 2000 lenses 323-1 and 323-2 are formed on lens arrays 351-1 and 351-2, respectively. In this case, approximately 2000 cemented lenses 323 are produced by disassembling the cemented lens array 351 into individual pieces.

[0087] <Second example of external configuration of a bonded lens array> Figure 14 shows a second example of the external configuration of the cemented lens array 351 shown in Figure 12.

[0088] Figure 14A is a perspective view of the cemented lens array 351, and Figures 14B and C are top views of lens arrays 351-1 and 351-2, respectively.

[0089] In the example shown in Figure 14, the top surfaces of lens arrays 351-1 and 351-2 are square with sides of 75 mm. Therefore, the top surface of cemented lens array 351 is also a square with sides of 75 mm. Approximately 5000 lenses 323-1 and 323-2 are formed on lens arrays 351-1 and 351-2 in Figure 14, respectively. In this case, approximately 5000 cemented lenses 323 are produced by splitting the cemented lens array 351 into individual pieces.

[0090] Note that the external dimensions of lens arrays 351-1 and 351-2 in Figures 13 and 14 are examples only and will be optimized depending on the size of the cemented lens 323 and the required yield. If the external dimensions of lens arrays 351-1 and 351-2 are approximately 3 to 8 inches, the number of cemented lenses 323 produced from one cemented lens array 351 will be several hundred to several thousand.

[0091] The materials used for lens arrays 351-1 and 351-2 can be resin materials such as thermoplastic resins, thermosetting resins, and energy-curable resins such as UV (ultraviolet) curable resins. Since energy-curable resins are liquid at room temperature, when the materials for lens arrays 351-1 and 351-2 are formed from energy-curable resins, the transferability is high.

[0092] The refractive indices of the materials for lens arrays 351-1 and 351-2 can be different. In the third embodiment, a high refractive index material such as a polycarbonate-based material is used as the material for lens array 351-1, and a low refractive index material such as a cyclic olefin copolymer (COC)-based material is used as the material for lens array 351-2.

[0093] <Example of external configuration of a bonded lens> Figure 15 shows an example of the external configuration of the cemented lens 323.

[0094] Figures 15A to C are the top view, side view, and rear view of the cemented lens 323, respectively.

[0095] As shown in Figures 15A and 15C, the outer shape of the cemented lens 323 is rectangular. In the example in Figure 15, the outer shape of the cemented lens 323 is a square with a side length of 1 mm.

[0096] As shown in Figure 15B, in the bonded lens 323, there is no adhesive layer between the bonding interface of lens 323-1, which is the object-side (upper side in the figure) surface 323-1a, and the bonding interface of lens 323-2, which is the image-side (lower side in the figure) surface 323-2b. That is, surfaces 323-1a and 323-2b are directly bonded together.

[0097] In the example shown in Figure 15, the distance between the object-side surface 323-2a of lens 323-2 and the image-side surface 323-1b of lens 323-1 is 0.33 mm. Surfaces 323-1a, 323-1b, 323-2a, and 323-2b are all aspherical.

[0098] Note that the length of one side of the outer shape of the cemented lens 323 in Figure 15 is just an example, and can be any value, for example, between 0.5 and 2 mm.

[0099] <Explanation of a bonded lens, where individually manufactured lenses are glued together.> Figure 16 illustrates a cemented lens in which individually fabricated lenses are bonded together with adhesive.

[0100] As shown in Figure 16, when a bonded lens 370 is formed by bonding individually manufactured lenses 371 and 372 together with an adhesive, the accuracy of the bonded lens 370 decreases. Specifically, in this case, the accuracy of the bonded lens 370 decreases due to processing errors in the bonding surface 371a of lens 371 and the bonding surface 372a of lens 372, variations in the thickness of the adhesive 373, etc.

[0101] In contrast, the bonded lens 323 is formed by integrating lenses 323-1 and 323-2 without using adhesive. Therefore, the precision of the bonded lens 323 is improved compared to the case where lenses 323-1 and 323-2, which are individually manufactured, are bonded together with adhesive.

[0102] <Explanation of the manufacturing method for individually producing lenses> Figures 17 to 19 illustrate the manufacturing method for individually producing lenses.

[0103] In manufacturing methods where lenses are produced individually, approximately 4 to 32 lenses are formed from a single mold. Therefore, to manufacture lenses for mobile devices, for example, which are produced in large quantities, several to more than a dozen molds and molding machines are required.

[0104] In this mold, as shown in Figure 17, a large proportion of the mold is occupied by branched channels called sprues 392 and runners 393 that carry resin to the lens section 391 where the lens is formed. Consequently, a large portion of the molded product is wasted. Therefore, material costs are high.

[0105] In contrast, when multiple bonded lenses 323 are molded together as a bonded lens array 351, hundreds to thousands of bonded lenses 323 can be manufactured at once. Furthermore, since runners 393 are unnecessary, there is less waste in the molded product. Therefore, material costs can be reduced.

[0106] In manufacturing methods where lenses are produced individually, ejector pins are required on the outer edge of the lens to remove it from the mold. Therefore, the outer edge of the lens is formed with a margin that also functions as this ejector pin, for example, to secure the lens with a holder when modularizing it.

[0107] As a result, as shown in Figure 18, when individually manufactured lenses 411 are modularized as a front lens group, the lens 411 is fixed to the holder 421 using the edge portion 411a of the lens 411. When the lens 412 and the cemented lens 413 are modularized as a rear lens group, the lens 412 is fixed to the holder 422 using the edge portion 412a of the lens 412, and the cemented lens 413 is fixed to the holder 422 using the edge portion 413a of the cemented lens 413. In the example in Figure 18, a spacer 423 is formed between the lens 412 and the cemented lens 413.

[0108] In contrast, when multiple cemented lenses 323 are molded together as a cemented lens array 351, the cemented lens array 351 is cut and separated into individual cemented lenses 323, thus eliminating the need for ejector pins. Consequently, the cemented lens 323 can be miniaturized and its area reduced. In this case, since no edge portion is formed on the cemented lens 323, the rear lens group lens 322 and the cemented lens 323 can be fixed together by lamination, for example, without using a holder. This allows for a smaller rear section 342 compared to the case where a holder is used.

[0109] In a manufacturing method for individually producing bonded lenses by integral molding, as shown on the left side of A in Figure 19, first, the first lens 441 of the bonded lens is molded in a mold 440. Then, as shown on the right side of A in Figure 19, the resin material 442, which is the material for the second lens of the bonded lens, is injected into the mold 440, and the second lens is integrally molded with lens 441.

[0110] In this case, if the object to be manufactured is a small bonded lens with a diameter of φ of 3 mm or less, the lens 441 is lightweight, and the pressure of the resin material 442 causes the lens 441 to shift from the mold 440, as shown in Figure 19B. This causes eccentricity, tilt, etc., in the lenses that make up the bonded lens, and the accuracy of the bonded lens deteriorates.

[0111] Furthermore, when manufacturing a small bonded lens, because the diameter of the bonded lens is small, the resin material 442 wraps around to the opposite side 441b of the bonded interface 441a, rather than the bonding interface 441a side, as shown in Figure 19C. As a result, the bonded lens cannot perform its intended function. However, this type of defect is less likely to occur when the bonded lens is a large lens with a diameter of several tens to several hundred mm.

[0112] In contrast, when multiple bonded lenses 323 are formed together as a bonded lens array 351, the diameter and side length of the bonded lens array 351 are, for example, about 75 mm to 150 mm (3 inches or more). Therefore, since lens 323-1 is less likely to move due to the pressure of the resin material of lens 323-2, the precision of the bonded lens 323 is less likely to deteriorate. Also, in this case, by injecting the resin material of lens 323-2 from near the center of the bonded lens array 351, it is possible to prevent the resin material from flowing around to surface 323-1b of lens 323-1 instead of surface 323-1a.

[0113] <First example of a method for fabricating a rear lens group> Figure 20 is a flowchart illustrating a first example of a method for fabricating a rear lens group.

[0114] In step S11 of Figure 20, molds for lens arrays 351-1 and 351-2 are manufactured by machining, semiconductor processing, etc. In step S12, lens array 351-1 is molded using the mold for lens array 351-1 manufactured in step S11. In step S13, lens array 351-2 is integrally molded with lens array 351-1, which was molded in step S12, using the mold for lens array 351-2 manufactured in step S11, without including an adhesive layer. This creates the bonded lens array 351.

[0115] In step S12, methods such as insert molding and two-color molding can be used to integrally mold the lens array 351-2 to the lens array 351-1. This method may also be combined with compression molding or heat and cool molding to improve resin filling and shape accuracy during molding of the thin-walled lens arrays 351-1 and 351-2, and to reduce birefringence. This makes it possible to produce a bonded lens array 351 with high optical performance.

[0116] If the materials for lens arrays 351-1 and 351-2 are energy-curable resins, methods such as thermal casting or UV imprinting may be used to integrally mold lens array 351-2 to lens array 351-1. In this method, integral molding is achieved by repeatedly applying and curing the energy-curable resin.

[0117] In step S14, the cemented lens array 351 is cut and separated into individual cemented lenses 323. As a result, the outer shape of the separated cemented lenses 323 becomes rectangular. Methods for separating the lenses include blade dicing, laser dicing, water jetting, and scribing. In step S15, the separated lenses 322 are laminated onto the cemented lenses 323 separated in step S14 and bonded with a thermosetting or UV-curing adhesive. This creates a rear lens group with a rectangular outer shape.

[0118] As described above, in the manufacturing method shown in Figure 20, the individualized lens 322 is stacked on the individualized cemented lens 323. Therefore, it is possible to individually adjust the alignment of the lens 322 with respect to the cemented lens 323 during stacking, and a highly accurate rear lens group can be manufactured.

[0119] <Second example of a method for fabricating a rear lens group> Figure 21 is a flowchart illustrating a second example of a method for fabricating the rear lens group.

[0120] The processes in steps S31 to S33 in Figure 21 are the same as those in steps S11 to S13 in Figure 20, so their explanation is omitted. In step S34, a lens array with multiple lenses 322 formed on it is laminated onto a bonded lens array 351 and bonded with a thermosetting or UV-curing adhesive. In step S35, the bonded lens array 351 with the lens arrays laminated in step S34 is cut and separated into rear lens elements. As a result, the outer shape of the rear lens element becomes rectangular.

[0121] As described above, in the manufacturing method shown in Figure 21, the cemented lens array 351 and the lens array with multiple lenses 322 formed on it are stacked together as a single lens array. Therefore, it is not possible to individually adjust the alignment of the lenses 322 relative to the cemented lens 323 during stacking, but the throughput of the rear lens group is high.

[0122] <Third example of a method for fabricating a rear lens group> Figure 22 is a flowchart illustrating a third example of a method for fabricating the rear lens group.

[0123] The processes in steps S51 to S53 in Figure 22 are the same as those in steps S11 to S13 in Figure 20, so their explanation is omitted. In step S54, the individualized lenses 322 are stacked on the cemented lens array 351 and bonded with a thermosetting or UV-curing adhesive. In step S55, the cemented lens array 351 on which the lenses 322 were stacked in step S54 is cut and separated into rear lens elements. As a result, the outer shape of the rear lens element becomes rectangular.

[0124] As described above, in the manufacturing method shown in Figure 22, the cemented lens array 351 and the lens 322 are stacked. Therefore, it is possible to adjust the alignment of the lens 322 with respect to the cemented lens 323 during stacking, albeit to a limited extent. The throughput of the rear lens group is higher than that of the manufacturing method shown in Figure 20, but lower than that of the manufacturing method shown in Figure 21.

[0125] <Optical path in the first design example of the optical system> Figure 23 is an optical path diagram showing the optical path of the first design example of the optical system 311.

[0126] When imaging an object at a predetermined position, the imaging device 300 focuses using either a pre-drive or post-drive method. As a result, the positional relationship of the lenses 321, 322, cemented lens 323, and BPF 324 with respect to the imaging surface 312a becomes as shown in Figure 23, for example. Consequently, the light incident on the imaging device 300 from the object is focused on the imaging surface 312a via the lenses 321, 322, cemented lens 323, and BPF 324, forming an image.

[0127] In the following, the object-side surface of lens 321 will be referred to as surface 321a, and the image-side surface will be referred to as surface 321b. Similarly, for lenses 322, 323-1, and 323-2, and BPF324, the object-side surfaces will be referred to as surfaces 322a, 323-1a, 323-2a, and 324a, respectively, and the image-side surfaces will be referred to as surfaces 322b, 323-1b, 323-2b, and 324b.

[0128] <Specifications of the first design example of the optical system> Figure 24 shows the specifications of the first design example of the optical system 311.

[0129] As shown in Figure 24, the focal length of the first design example of the optical system 311 is 0.301 mm, the FNo is 3.03, the image height is 0.354 mm, and the total length TL is 1.5 mm.

[0130] <Setting data for the first design example of the optical system> Figure 25 shows the setting data (RDN) for the first design example of the optical system 311.

[0131] In the table in Figure 25, the first row from the top lists the following items for each column: surface number, surface type, radius of curvature [mm], effective diameter [mm], spacing [mm], nd, and vd. Each row from the second row onward corresponds to the surface of the object (subject) being imaged, specifically surfaces 321a, 321b, 322a, 322b, 323-2a, 323-2b (323-1a), 323-1b, 324a, and 324b. The same applies to Figure 29, which will be discussed later.

[0132] As shown in the second row from the top of Figure 25, the surfaces of the object being imaged are not assigned surface numbers, and the surface type is simply "Object". The radius of curvature of the surface of the object being imaged is infinite (inf), and the distance between it and surface 321a, which is assigned surface number 1, is 10.000 mm.

[0133] As shown in the third row from the top of Figure 25, the surface number of surface 321a is 1, and the surface type of surface 321a is aspherical (ASP). The radius of curvature of surface 321a is 1.7130 mm, and the distance between it and surface 321b, which is assigned surface number 2, is 0.0783 mm. The refractive index nd of surface 321a for the d line (wavelength 587.6 nm) is 1.5445, and the Abbe number vd for the d line is 56.240.

[0134] As shown in the 4th to 11th rows from the top of Figure 25, surfaces 321b, 322a, 322b, 323-2a, 323-2b(323-1a), 323-1b, 324a, and 324b are assigned surface numbers from 2 to 9 in order. As shown in the 4th to 9th rows from the top of Figure 25, surfaces 321b, 322a, 322b, 323-2a, 323-2b(323-1a), and 323-1b are aspherical. Although not shown in Figure 23, the optical system 311 is provided with an aperture stop (STO) at the position of surface 322b, which is assigned surface number 4. As shown in the 10th and 11th rows from the top of Figure 25, surfaces 324a and 324b are filters, and their radius of curvature is infinite.

[0135] The radius of curvature, effective diameter, and spacing from the next numbered surface to surfaces 321b, 322a, 322b, 323-2a, 323-2b (323-1a), and 323-1b are the values ​​listed in the 4th to 9th rows from the top of Figure 25. For example, the effective diameters of surfaces 323-2a, 323-2b (323-1a), and 323-1b are 0.374043 mm, 0.384428 mm, and 0.44787 mm, respectively.

[0136] The refractive indices nd and Abbe numbers vd for surfaces 322a, 323-2a, 323-2b (323-1a), and 324a are the values ​​listed in the 5th, 7th, 8th, and 10th rows from the top of Figure 25. For example, the refractive index nd for surface 323-2a is 1.5445 and the Abbe number vd is 56.240. The refractive index nd for surface 323-2b (323-1a) is 1.6613 and the Abbe number vd is 20.360.

[0137] Therefore, the refractive index nd of lens array 351-1 (first lens array) of lens 323-1 is higher than the refractive index nd of lens array 351-2 (second lens array) of lens 323-2. The Abbe number vd of lens array 351-1 is smaller than the Abbe number vd of lens array 351-2.

[0138] The refractive index nd of lens array 351-1 is preferably 1.58 or greater, and the refractive index nd of lens array 351-2 is preferably less than 1.58. The Abbe number vd of lens array 351-1 is preferably less than 35, and the Abbe number vd of lens array 351-2 is preferably 35 or greater.

[0139] The distance between surface 324a and surface 324b, which is assigned the next surface number, and the distance between surface 324b and imaging surface 312a are the values ​​listed in the 10th and 11th rows from the top of Figure 25, respectively.

[0140] As shown in Figure 25, the effective diameters of surfaces 321a, 321b, 322a, 322b, 323-2a, 323-2b (323-1a), and 323-1b are all 1 mm or less. The total length TL of the optical system 311, i.e., the sum of the spacing between surfaces 321a, 321b, 322a, 322b, 323-2a, 323-2b (323-1a), 323-1b, 324a, and 324b, is approximately 1.5 mm.

[0141] <Aspherical data for each surface in the first design example of the optical system> Figure 26 shows the aspherical data for surfaces 321a, 321b, 322a, 322b, 323-2a, 323-2b (323-1a), and 323-1b in a first design example of the optical system 311.

[0142] Here, the surface profile of an aspherical lens is expressed by the following equation (1).

[0143]

number

[0144] In equation (1), Z is the sag, H is the distance from the optical axis, and R is the radius of curvature. k is the cone constant, and A 2i (where i is an integer from 2 to 8) are the aspherical coefficients.

[0145] In the first row from the top of the table in FIG. 26, as items for each column, there are the surface number, the conic constant k of Equation (1), and the aspherical coefficients A4, A6, A8, A 10 , A 12 , A 14 , and A 16 are described. Each row from the second row from the top corresponds to each of the surfaces 321a, 321b, 322a, 322b, 323-2a, 323-2b (323-1a), and 323-1b. The same applies to FIG. 30 described later.

[0146] As described in the second row from the top of FIG. 26, the conic constant k of the surface 321a to which the surface number 1 is assigned is 0. The aspherical coefficients A4, A6, A8, A 10 , A 12 , A 14 , and A 16 are, respectively, -8.52, 1.55×10 2 , -2.81×10 3 , 4.87×10 4 , -4.90×10 5 , 2.48×10 6 , -4.97×10 6 .

[0147] The conic constant k, the aspherical coefficients A4, A6, A8, A 10 , A 12 , A 14 , and A 16 for each of the surfaces 321b, 322a, 322b, 323-2a, 323-2b (323-1a), and 323-1b are as described in the third to eighth rows from the top of FIG. 26.

[0148] <Optical path of the second design example of the optical system> FIG. 27 is an optical path diagram showing the optical path of the second design example of the optical system 311.

[0149] When imaging an object at a predetermined position, the imaging device 300 focuses using either a pre-drive or post-drive method. As a result, the positional relationship of the lenses 321, 322, cemented lens 323, and BPF 324 with respect to the imaging surface 312a becomes as shown in Figure 27, for example. Consequently, the light incident on the imaging device 300 from the object is focused on the imaging surface 312a via the lenses 321, 322, cemented lens 323, and BPF 324, forming an image.

[0150] <Specifications of the second design example of the optical system> Figure 28 shows the specifications of a second design example of the optical system 311.

[0151] As shown in Figure 28, the second design example of the optical system 311 has a focal length of 0.401 mm, an FNo of 3.07, an image height of 0.354 mm, and an overall length TL of 1.5 mm.

[0152] <Setting data for the second design example of the optical system> Figure 29 shows the setting data for a second design example of the optical system 311.

[0153] As indicated in the second, tenth, and eleventh lines from the top of Figure 29, the setting data for the surface of the object to be imaged, surface 324a, and surface 324a are the same as the setting data in Figure 25.

[0154] As indicated in the third to ninth rows from the top of Figure 29, the surface numbers and surface types of surfaces 321a, 321b, 322a, 322b, 323-2a, 323-2b (323-1a), and 323-1b are the same as those in Figure 25. Similar to Figure 23, although not shown in Figure 27, an aperture diaphragm is provided in the optical system 311 at the position of surface 322b.

[0155] The radius of curvature, effective diameter, and spacing from the next numbered surface to surfaces 321a, 321b, 322a, 322b, 323-2a, 323-2b (323-1a), and 323-1b are the values ​​listed in the 3rd to 9th rows from the top of Figure 29. As shown in the 3rd, 5th, 7th, and 8th rows from the top of Figure 29, the refractive index nd and Abbe number vd of surfaces 321a, 322a, 323-2a, and 323-2b (323-1a) are the same as the refractive index nd and Abbe number vd in Figure 25.

[0156] As shown in Figure 29, the effective diameters of surfaces 321a, 321b, 322a, 322b, 323-2a, 323-2b (323-1a), and 323-1b are all 1 mm or less. The total length TL of the optical system 311, i.e., the sum of the spacing between surfaces 321a, 321b, 322a, 322b, 323-2a, 323-2b (323-1a), 323-1b, 324a, and 324b, is approximately 1.5 mm.

[0157] <Aspherical data for each surface in the second optical system design example> Figure 30 shows the aspherical data for surfaces 321a, 321b, 322a, 322b, 323-2a, 323-2b (323-1a), and 323-1b in a second design example of the optical system 311.

[0158] The cone constant k and aspheric coefficients A4, A6, A8, A for each of the faces 321a, 321b, 322a, 322b, 323-2a, 323-2b (323-1a), and 323-1b. 10 ,A 12 ,A 14 , and A 16 This is as described in the second to eighth lines from the top of Figure 30.

[0159] <Explanation of the effects of cemented lenses> Figure 31 illustrates the effect of the cemented lens 323.

[0160] In the table in Figure 31, the first column from the left lists the following items for each row: type of optical system, configuration of the optical system, total length TL of the optical system, spherical aberration (axial chromatic aberration), and amount of axial chromatic aberration for light with wavelengths from 486 nm to 656 nm. The columns from the second column onward from the left correspond to the optical system without the cemented lens 323, the first design example of the optical system 311, and the second design example of the optical system 311, respectively.

[0161] As shown in the second column from the left in the table in Figure 31, the optical system that does not include the cemented lens 323 is the optical system 511, in which three lenses 501-503 and a BPF 504 are arranged in order from the object side. The imaging plane 512 is located downstream of the optical system 511, that is, on the image side of the BPF 504. The effective diameter of the lens 501 closest to the object in the optical system 511 is approximately 0.89 mm, and the total length TL is 1.49 mm. The spherical aberration of the optical system 511 is shown in the graph in the fourth row from the top in the second column from the left in the table in Figure 31.

[0162] The graph in the fourth row of the table in Figure 31 shows the vertical spherical aberration for each wavelength of light at 486.1327 nm, 587.5618 nm, and 656.2725 nm. The horizontal axis of this graph represents the focal position (Focus) [mm], and the vertical axis represents the normalized pupil coordinates. As shown in the fifth row from the top, based on the graph in the fourth row from the top in the second column from the left of the table in Figure 31, the axial chromatic aberration of light with wavelengths from 486 nm to 656 nm in optical system 511 is 19.7 μm.

[0163] As shown in the third column from the left of the table in Figure 31, in the first design example of the optical system 311 described in Figures 23 to 26, the effective diameter of the lens 321 closest to the object is approximately 0.73 mm, and the total length TL of the optical system 311 is 1.50 mm. The spherical aberration of the first design example of the optical system 311 is shown in the graph in the fourth row from the top of the third column from the left of the table in Figure 31. As shown in the fifth row from the top of the table in Figure 31, the axial chromatic aberration of light with wavelengths of 486 nm to 656 nm in the first design example of the optical system 311 is 4.4 μm.

[0164] As shown in the fourth column from the left in the table in Figure 31, in the second design example of the optical system 311 described in Figures 27 to 30, the effective diameter of the lens 321 closest to the object is approximately 0.86 mm, and the total length TL of the optical system 311 is 1.50 mm. The spherical aberration of the second design example of the optical system 311 is shown in the graph in the fourth row from the top in the fourth column from the left in the table in Figure 31. As shown in the fifth row from the top in the graph in the fourth row from the top in the fourth column from the left in the table in Figure 31, the axial chromatic aberration of light with wavelengths of 486 nm to 656 nm in the second design example of the optical system 311 is 4.0 μm.

[0165] As described above, the total length TL and the effective diameter of the lens 501 or 321 closest to the object are approximately the same for the optical system 511 without the cemented lens 323, the first design example of the optical system 311, and the second design example of the optical system 311. Furthermore, the amount of on-axial chromatic aberration of light with wavelengths of 486 nm to 656 nm in the first and second design examples of the optical system 311 is approximately 1 / 4 the amount of on-axial chromatic aberration of light with wavelengths of 486 nm to 656 nm in the optical system 511. Therefore, it can be said that the on-axial chromatic aberration of light with wavelengths of 486 nm to 656 nm can be significantly improved in the optical system 311 by including the cemented lens 323. In other words, the optical system 311 can realize a compact and high-performance optical system by including three aspherical lenses: lens 321, lens 322, and cemented lens 323.

[0166] As described above, this bonded lens 323 is formed by cutting a bonded lens array 351 in which lens arrays 351-1 and 351-2 are integrally molded without an adhesive layer at the bonding interface. Therefore, a small bonded lens 323 can be manufactured at low cost and with high precision.

[0167] Furthermore, the imaging device 300 includes an optical system 311 and an image sensor 312, and the lens 322 and cemented lens 323 located on the image side of the optical system 311 are fixed to the image sensor 312. Therefore, the imaging device 300 can perform focusing drive using, for example, a pre-drive system or a post-drive system. As a result, the focusing drive stroke amount can be optimized.

[0168] <5. Fourth Embodiment> <Example of imaging device configuration> Figure 32 shows an example configuration of a fourth embodiment of an imaging device to which this technology is applied.

[0169] The imaging device 600 in Figure 32 comprises an optical system 611 and an image sensor 612. In the imaging device 600, the six lenses 621-626 and one cemented lens 627 that constitute the ultra-wide-angle lens, which are included in the optical system 111, are divided into a front lens group and a rear lens group, and the rear lens group is fixed to the image sensor 612.

[0170] Specifically, the optical system 611 of the imaging device 600 comprises six lenses 621-626, one cemented lens 627, a BPF 628, and an aperture diaphragm 629. The six lenses 621-626 and the one cemented lens 627 are divided into a front lens group consisting of five lenses 621-625 on the object side and the cemented lens 627, and a rear lens group consisting of one lens 626 on the image side.

[0171] The front lens group, BPF628, and aperture diaphragm 629 are arranged from the object side in the following order: lens 621, lens 622, aperture diaphragm 629, lens 623, cemented lens 627, lens 624, lens 625, and BPF628. Although not shown in the diagram, the front lens group has legs formed on its periphery, and each lens of the front lens group is fixed at its respective interval by being stacked. The cemented lens 627 is formed by bonding lens 627-2 to the object side of lens 627-1.

[0172] A lens section 631, including a single lens 626 which is a rear lens group, is directly fixed to the object side of the image sensor 612. The lens section 631 consists of the lens 626, which is the optically effective part, and a lens holding section 641 that fixes the lens 626 to the image sensor 612. The lens holding section 641 is joined to the imaging surface 612a, which is the object side surface of the image sensor 612. At least one surface of the lens holding section 641 is flat. An air layer is formed between the lens 626 and the image sensor 612. Note that the lens 626 and the lens holding section 641 may be formed as an integrated unit, similar to the lens 127 and lens holding section 141 in Figure 3, or they may be formed as separate parts.

[0173] Light incident on the imaging device 600 from the subject is focused via the optical system 611 and irradiated onto the imaging surface 612a of the imaging sensor 612. The imaging sensor 612 converts the light irradiated onto the imaging surface 612a into an electrical signal and generates an imaging signal.

[0174] The imaging device 600 configured as described above achieves focusing by a front-stage drive system that drives a front-stage section 651 consisting of a front lens group, a BPF 628, and an aperture diaphragm 629. Alternatively, the imaging device 600 achieves focusing by a rear-stage drive system that drives a rear-stage section 652 consisting of an image sensor 612 to which a rear lens group is fixed.

[0175] In the example shown in Figure 32, the front lens group is composed of lenses 621-625 and a cemented lens 627, and the rear lens group is composed of lens 626. However, the method of dividing the front and rear lens groups is arbitrary.

[0176] <Example of optical system specifications> Figure 33 shows an example of the specifications of the optical system 611 in Figure 32.

[0177] In the example shown in Figure 33, the focal length of optical system 611 is 2.37 mm, the FNo is 2.26, and the image height is 3.68 mm. The field of view of optical system 611 is 125 deg, and the total length TL is 7.1 mm. The lateral magnification β of the rear lens group of optical system 611 is 0.919, and the value d / TL is 0.12.

[0178] Note that each value in FIG. 33 is an example and can be any value. It is desirable that the lateral magnification β of the optical system 611 satisfies 0.89 < β < 1.23. It is desirable that d / TL satisfies 0 < d / TL < 0.5.

[0179] <Example of Focus Drive Stroke Amount> FIG. 34 is a diagram showing an example of the focus drive stroke amount in the imaging device 600 of FIG. 32.

[0180] The solid line in FIG. 34 represents the amount of extension of the front part 651 corresponding to each shooting distance when the imaging device 600 performs focus drive in the front drive method. The dotted line in FIG. 34 represents the amount of extension of the entire optical system 611 corresponding to each shooting distance when the imaging device having the optical system 611 performs focus drive in the entire optical system drive method.

[0181] As shown by the solid line in FIG. 34, in the front drive method, the focus drive stroke amount Sw, which ranges from the amount of extension when the shooting distance is 100 m to the amount of extension when the shooting distance is the closest distance close to 0.10 m 11 is about 39.5 μm.

[0182] On the other hand, as shown by the dotted line in FIG. 34, in the entire optical system drive method, the focus drive stroke amount Sw, which ranges from the amount of extension when the shooting distance is 100 m to the amount of extension when the shooting distance is the closest distance close to 0.10 m 12 is about 33.5 μm. Therefore, the focus drive stroke amount Sw 11 is about 1.18 times (= 39.5 / 33.5) of the focus drive stroke amount Sw 12 That is, the focus drive stroke amount Sw 11 is enlarged by about 18% with respect to the focus drive stroke amount Sw 12 .

[0183] As described above, by performing focusing drive using a pre-stage drive method, the imaging device 600 can achieve a longer focusing drive stroke compared to when focusing drive is performed using an overall optical system drive method. Therefore, the focusing accuracy is less constrained by the drive resolution of the actuator that drives the pre-stage 651. Thus, even when the drive resolution of the actuator is large, i.e., when the pitch that can drive the pre-stage 651 is large, it is possible to sufficiently improve the focusing accuracy.

[0184] Although not shown in the diagram, the focusing drive stroke in the downstream drive system can also be made longer than when focusing is performed using the entire optical system drive system, similar to the focusing drive stroke in the upstream drive system.

[0185] As described above, the imaging device 600 comprises an optical system 611 and an image sensor 612, and the lens 626 located on the image side of the optical system 611 is fixed to the image sensor 612. Therefore, the imaging device 600 can perform focusing drive using, for example, a pre-drive system or a post-drive system. As a result, the focusing drive stroke amount can be optimized.

[0186] For example, in the imaging device 600, the lens 626 has a lateral magnification β satisfying 0.89 < β < 1, which allows the focusing drive stroke to be expanded to 1 to 1.18 times that of the overall optical system drive method. As a result, the focusing accuracy of the imaging device 600, in which the optical system 611 constitutes an ultra-wide-angle lens, can be significantly improved.

[0187] Furthermore, by including the cemented lens 627 in the optical system 611, a high-performance optical system can be realized, similar to the third embodiment. The small cemented lens 627 can be manufactured at low cost and with high precision using the same manufacturing method as in the third embodiment.

[0188] <6. Fifth Embodiment> <Example of imaging device configuration> Figure 35 shows an example configuration of a fifth embodiment of an imaging device to which this technology is applied.

[0189] The imaging device 700 in Figure 35 comprises an optical system 711 and an image sensor 712. In the imaging device 700, the three lenses 721-723 that constitute the telephoto lens, the prism 724, and the one cemented lens 725 included in the optical system 711 are divided into a front lens group and a rear lens group, and the rear lens group is fixed to the image sensor 712.

[0190] Specifically, the optical system 711 of the imaging device 700 includes three lenses 721-723, a prism 724, one cemented lens 725, and a BPF 726. The lenses 721-723, the prism 724, and the cemented lens 725 are divided into a front lens group consisting of the three lenses 721-723 and the prism 724 on the object side, and a rear lens group consisting of the cemented lens 725 on the image side.

[0191] The front lens group and BPF726 are arranged from the object side in the following order: lenses 721, 722, 723, prism 724, and BPF726. Although not shown in the diagram, lenses 721-723, prism 724, and BPF726 are fixed at their respective intervals by holders or the like.

[0192] A lens section 731, including a single cemented lens 725 which is a rear lens group, is directly fixed to the object side of the image sensor 712. The cemented lens 725 is formed by bonding lens 725-2 to the object side of lens 725-1.

[0193] The lens portion 731 consists of a cemented lens 725, which is the optically effective portion, and a lens holder portion 741 that fixes the cemented lens 725 to the image sensor 712. The lens holder portion 741 is bonded to the imaging surface 712a, which is the object-side surface of the image sensor 712. At least one surface of the lens holder portion 741 is flat. An air layer is formed between the cemented lens 725 and the image sensor 712. The cemented lens 725 and the lens holder portion 741 may be formed as an integrated unit, similar to the lens 127 and lens holder portion 141 in Figure 3, or they may be formed as separate parts.

[0194] The light incident on the imaging device 700 from the object is condensed through the optical system 711 and irradiated onto the imaging surface 712a of the imaging sensor 712. The imaging sensor 712 converts the light irradiated onto the imaging surface 712a into an electrical signal and generates an imaging signal.

[0195] The imaging device 700 configured as described above performs focusing in a front-stage driving method that drives the front-stage portion 751 composed of the front-group lens and the BPF 726, or in a rear-stage driving method that drives the rear-stage portion 752 composed of the imaging sensor 712 with the rear-group lens fixed.

[0196] In the example of FIG. 35, the front-group lens is composed of lenses 721 to 723 and the prism 724, and the rear-group lens is composed of the cemented lens 725. However, the method of dividing the front-group lens and the rear-group lens is arbitrary.

[0197] <Example of specifications of the optical system> FIG. 36 is a diagram showing an example of the specifications of the optical system 711 in FIG. 35.

[0198] In the example of FIG. 36, the focal length of the optical system 711 is 15.6 mm, the FNo is 2.8, and the image height is 2.94 mm. The angle of view of the optical system 711 is 21 deg, and the overall length TL is 20 mm. The lateral magnification β of the rear-group lens of the optical system 711 is 1.22, and the value d / TL is 0.1.

[0199] Note that each value in FIG. 36 is an example and can be any value. It is desirable that the lateral magnification β of the optical system 711 satisfies 0.89 < β < 1.23. It is desirable that the value of d / TL satisfies 0 < d / TL < 0.5.

[0200] <Example of focusing drive stroke amount> FIG. 37 is a diagram showing an example of the focusing drive stroke amount in the imaging device 700 of FIG. 35.

[0201] The solid lines in Figure 37 represent the extension amount of the front section 751 corresponding to each shooting distance when the imaging device 700 performs focusing drive using a front-stage drive method. The dotted lines in Figure 37 represent the extension amount of the entire optical system 711 corresponding to each shooting distance when the imaging device having an optical system 711 performs focusing drive using an overall optical system drive method.

[0202] As shown by the solid line in Figure 37, in the pre-drive system, the focusing drive stroke amount St is the range from the extension amount when the shooting distance is 100m to the extension amount when the shooting distance is close to 0.10m. 11 However, it is 2100 μm.

[0203] In contrast, as shown by the dotted line in Figure 37, in the overall optical system drive method, the focusing drive stroke amount St is the range from the extension amount when the shooting distance is 100m to the extension amount when the shooting distance is close to 0.10m. 12 It is 3100 μm. Therefore, the focusing drive stroke amount St 11 The focusing drive stroke amount St 12 It is approximately 0.67 times (=2100 / 3100). That is, the focusing drive stroke amount St 11 The focusing drive stroke amount St 12 It will be reduced by approximately 30%.

[0204] As described above, by performing the focusing drive using a pre-stage drive method, the imaging device 700 can shorten the focusing drive stroke compared to when focusing is performed using an overall optical system drive method. Therefore, the imaging device 700 can be miniaturized.

[0205] Although not shown in the diagram, the focusing drive stroke in the downstream drive system can also be made shorter than when focusing is performed using the entire optical system drive system, similar to the focusing drive stroke in the upstream drive system.

[0206] As described above, the imaging device 700 comprises an optical system 711 and an image sensor 712, and the cemented lens 725 located on the image side of the optical system 711 is fixed to the image sensor 712. Therefore, the imaging device 700 can perform focusing drive using, for example, a pre-drive system or a post-drive system. As a result, the focusing drive stroke amount can be optimized.

[0207] For example, in the imaging device 700, the cemented lens 725 has a lateral magnification β satisfying 1 < β < 1.23, which allows the focusing drive stroke to be reduced to 0.67 to 1 times compared to the overall optical system drive method. As a result, the imaging device 700, in which the optical system 711 constitutes a telephoto lens, can be miniaturized.

[0208] Furthermore, by including the cemented lens 725 in the optical system 711, a high-performance optical system can be realized, similar to the third embodiment. The small cemented lens 725 can be manufactured at low cost and with high precision using the same manufacturing method as in the third embodiment.

[0209] In the third to fifth embodiments, the bonded lens 323 (627,725) had a two-layer structure in which two lenses 323-1 (627-1,725-1) and 323-2 (627-2,725-2) were bonded together, but it may also have a structure of three or more layers. When the bonded lens 323 (627,725) has a structure of three or more layers, the bonded lens 323 (627,725) is formed by cutting a bonded lens array in which three or more lens arrays are integrally molded without including an adhesive layer at at least one bonding interface.

[0210] In the third to fifth embodiments, the optical system 311 (611, 711) includes one cemented lens 323 (627, 725), but it may include multiple cemented lenses. In this case, the cemented lens may be included in both the front lens group and the rear lens group, or all the cemented lenses may be included in either the front lens group or the rear lens group. The cemented lenses included in the front lens group and the rear lens group and the other lenses are fixed together, for example, by stacking.

[0211] <7. Examples of Imaging Device Usage> Figure 38 shows an example of use using the imaging device 100 (200, 300, 600, 700) described above.

[0212] The imaging devices 100 (200, 300, 600, 700) described above can be used in various cases for sensing light such as visible light, infrared light, ultraviolet light, and X-rays, for example, as follows.

[0213] • Devices that capture images for viewing purposes, such as digital cameras and portable devices with camera functions. Devices used for traffic purposes, such as on-board sensors that photograph the front, rear, surroundings, and interior of a vehicle for safe driving such as automatic stopping, and for recognizing the driver's condition; surveillance cameras that monitor moving vehicles and roads; and distance measuring sensors that measure the distance between vehicles. A device used in home appliances such as TVs, refrigerators, and air conditioners to capture user gestures and perform device operations according to those gestures. • Devices used for medical and healthcare purposes, such as endoscopes and devices that perform angiography using infrared light reception. • Security devices such as surveillance cameras for crime prevention and cameras for person recognition. • Devices used for cosmetic purposes, such as skin measuring devices for photographing skin and microscopes for photographing the scalp. • Action cameras, wearable cameras, and other devices used for sports purposes. • Cameras and other devices used for agricultural purposes to monitor the condition of fields and crops.

[0214] <5. Examples of application to electronic devices> This technology is not limited to applications to imaging devices. The technology disclosed herein is applicable to all electronic devices that use an imaging sensor in the image acquisition unit (photoelectric conversion unit), such as cameras like digital still cameras and video cameras, portable terminal devices with imaging functions, and photocopiers that use an imaging sensor in the image reading unit. The imaging sensor may be formed as a single chip, or it may be in the form of a module with imaging functions in which the imaging unit and signal processing unit or optical system are packaged together.

[0215] Figure 39 is a block diagram showing an example configuration of a camera as an electronic device to which this technology is applied.

[0216] The camera 1000 in Figure 39 comprises an imaging device 1001, a drive unit 1002, and a DSP (Digital Signal Processor) circuit 1003, which is a camera signal processing circuit. The camera 1000 also includes a frame memory 1004, a display unit 1005, a recording unit 1006, an operation unit 1007, and a power supply unit 1008. The drive unit 1002, DSP circuit 1003, frame memory 1004, display unit 1005, recording unit 1006, operation unit 1007, and power supply unit 1008 are interconnected via a bus line 1009.

[0217] The imaging device 1001 captures incident light (image light) from the subject, forms an image on the imaging surface, and converts the amount of the formed incident light into an electrical signal on a pixel-by-pixel basis, outputting it as an imaging signal. The imaging device 1001 used is the imaging device 100 (200, 300, 600, 700) described above. The drive unit 1002 performs focusing drive on the imaging device 1001 using either a pre-drive method or a post-drive method.

[0218] The display unit 1005 is composed of a thin display such as an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence) display, and displays video or still images captured by the imaging device 1001. The recording unit 1006 records the video or still images captured by the imaging device 1001 onto a recording medium such as a hard disk or semiconductor memory.

[0219] The control unit 1007 issues operation commands for various functions of the camera 1000 under the user's control. The power supply unit 1008 appropriately supplies various power sources to the drive unit 1002, DSP circuit 1003, frame memory 1004, display unit 1005, recording unit 1006, and control unit 1007.

[0220] As described above, in camera 1000, the imaging device 100 (200, 300, 600, 700) is used as the imaging device 1001, so the focusing drive stroke amount can be optimized.

[0221] <9. Examples of applications to mobile devices> The technology disclosed herein (the Technology) can be applied to a variety of products. For example, the Technology disclosed herein may be implemented as a device mounted on any type of mobile vehicle, such as an automobile, electric vehicle, hybrid electric vehicle, motorcycle, bicycle, personal mobility device, airplane, drone, ship, or robot.

[0222] Figure 40 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0223] The vehicle control system 12000 comprises multiple electronic control units connected via a communication network 12001. In the example shown in Figure 40, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is also shown, consisting of a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0224] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0225] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0226] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0227] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0228] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that images the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0229] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking system based on information from inside and outside the vehicle acquired by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0230] Further, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving or the like that autonomously travels without relying on the driver's operation by controlling a driving force generator, a steering mechanism, a braking device, or the like based on the information around the vehicle acquired by the out-vehicle information detection unit 12030 or the in-vehicle information detection unit 12040.

[0231] Further, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the out-vehicle information acquired by the out-vehicle information detection unit 12030. For example, the microcomputer 12051 can perform cooperative control for the purpose of anti-glare, such as controlling the headlamp according to the position of the preceding vehicle or oncoming vehicle detected by the out-vehicle information detection unit 12030 and switching the high beam to the low beam.

[0232] The audio-visual output unit 12052 transmits at least one of an audio output signal and an image output signal to an output device capable of notifying information visually or auditorily to the vehicle occupants or outside the vehicle. In the example of FIG. 40, the audio speaker 12061, the display unit 12062, and the instrument panel 12063 are illustrated as the output devices. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0233] FIG. 41 is a diagram showing an example of the installation position of the imaging unit 12031.

[0234] In FIG. 41, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0235] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0236] Figure 41 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0237] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0238] For example, the microcomputer 12051, based on distance information obtained from imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to vehicle 12100). In particular, it can extract the nearest object on the vehicle 12100's path that is traveling in approximately the same direction as vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0239] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, heavy vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid a collision by outputting a warning to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0240] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio-image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio-image output unit 12052 may also control the display unit 12062 to display an icon indicating a pedestrian at a desired position.

[0241] The above describes an example of a vehicle control system to which the technology described herein can be applied. The technology described herein can be applied to the imaging unit 12031 and other components of the configuration described above. Specifically, the imaging device 100 (200, 300, 600, 700) can be applied to the imaging unit 12031. By applying the technology described herein to the imaging unit 12031, the amount of focus drive stroke can be optimized. As a result, it becomes possible to miniaturize the imaging unit 12031 and reduce driver fatigue by acquiring clearer captured images.

[0242] In this specification, a system refers to a collection of multiple components (devices, modules (parts), etc.), regardless of whether all components are located in the same enclosure. Therefore, multiple devices housed in separate enclosures and connected via a network, and a single device containing multiple modules within a single enclosure, are both considered systems.

[0243] The embodiments of this technology are not limited to those described above, and various modifications are possible without departing from the spirit of this technology.

[0244] For example, a combination of all or some of the above-described embodiments can be adopted. For instance, in the fifth embodiment, the front lens group may include a cemented lens, while the rear lens group may not include a cemented lens.

[0245] The effects described herein are merely illustrative and not limited to those described herein; other effects may also occur.

[0246] This technology can take the following configuration: (1) An optical system having multiple lenses, Imaging unit and Equipped with, The rear lens group, which consists of one or more lenses arranged on the imaging unit side of the optical system, is fixed to the imaging unit. It is configured in such a way Imaging device. (2) An air layer is formed between the rear lens group and the imaging unit. It is configured in such a way The imaging device described in (1) above. (3) The optical system constitutes a wide-angle lens, The lateral magnification β of the rear lens group is, 0.89 < β < 1 satisfies It is configured in such a way The imaging device described in (1) or (2) above. (4) The aforementioned optical system constitutes a telephoto lens, The lateral magnification β of the rear lens group is, 1 < β < 1.23 satisfies It is configured in such a way The imaging device described in (1) or (2) above. (5) The rear group lens is fixed to the imaging unit by a lens holding unit configured as The imaging device according to any one of (1) to (4) above (6) The rear group lens and the lens holding unit are integrally formed by molding a resin material or glass The imaging device according to (5) above (7) When the total length of the optical system is TL and the distance from the most object-side surface of the rear group lens to the imaging unit is d 0 < d / TL < 0.5 satisfying configured as The imaging device according to any one of (1) to (6) above (8) At least one of the plurality of lenses is a cemented lens configured as The imaging device according to any one of (1) to (7) above (9) The outer shape of the cemented lens is rectangular configured as The imaging device according to (8) above (10) The cemented lens is formed by cutting a cemented lens array in which two or more lens arrays are integrally molded without including an adhesive layer at at least one cemented interface The imaging device according to (9) above (11) The two or more lens arrays include a first lens array and a second lens array The refractive index of the first lens array is higher than that of the second lens array, and the Abbe number of the first lens array is smaller than that of the second lens array configured as The imaging device according to (10) above (12) The refractive index of the first lens array is 1.58 or more and the Abbe number is less than 35 The refractive index of the second lens array is less than 1.58, and the Abbe number is 35 or greater. It is configured in such a way The imaging device described in (11) above. (13) The plurality of lenses are arranged in the order of the first lens, the second lens, and the cemented lens, from the object side toward the image plane. The first lens, the second lens, and the cemented lens are aspherical lenses. It is configured in such a way The imaging device described in any of (8) to (12) above. (14) The aforementioned plurality of lenses are formed from a resin material. It is configured in such a way The imaging device described in any of (8) to (13) above. (15) The aforementioned group of lenses is composed of the rear lens group and the front lens group, which is a lens other than the rear lens group. At least one of the front lens group and the rear lens group is a lens group with a cemented lens, which is composed of a plurality of lenses including the cemented lens. The aforementioned bonded lens group is formed by stacking the individual lenses that make up the bonded lens group. It is configured in such a way An imaging device as described in any of (8) to (14) above. (16) The outer shape of the aforementioned lens group with a cemented lens is rectangular. It is configured in such a way The imaging device described in (15) above. (17) The bonded lens is formed by cutting a bonded lens array in which two or more lens arrays are integrally molded without an adhesive layer at at least one bonding interface. The aforementioned bonded lens group is formed by stacking the bonded lens and the lenses other than the bonded lens that constitute the bonded lens group. The imaging device described in (16) above. (18) The aforementioned bonded lens group is formed by stacking and cutting a bonded lens array in which two or more lens arrays are integrally molded without an adhesive layer at at least one bonding interface, and an array of lenses other than the bonded lens that constitutes the bonded lens group. The imaging device described in (16) above. (19) The aforementioned bonded lens group is formed by stacking and cutting a bonded lens array, in which two or more lens arrays are integrally molded without an adhesive layer at at least one bonding interface, and lenses other than the bonded lens that constitute the bonded lens group. The imaging device described in (16) above. (20) A front lens, which is one of the plurality of lenses other than the rear lens, or a drive unit that drives the imaging unit to focus the rear lens to which the rear lens is fixed. Furthermore, it is equipped with The imaging device according to any one of (1) to (19) above. [Explanation of Symbols]

[0247] 100 Imaging device, 111 Optical system, 113 Imaging sensor, 121~127 Lens, 200 Imaging device, 211 Optical system, 213 Imaging sensor, 221~224 Lens, 225 Prism, 300 Imaging device, 311 Optical system, 312 Imaging sensor, 321,322 Lens, 323 Cemented lens, 351 Cemented lens array, 351-1,351-2 Lens array, 1000 Camera, 1001 Imaging device, 1002 Drive unit

Claims

1. An optical system having multiple lenses, Imaging unit and Equipped with, The rear lens group, which consists of one or more lenses arranged on the imaging unit side of the optical system, is fixed to the imaging unit. It is configured in such a way Imaging device.

2. An air layer is formed between the rear lens group and the imaging unit. It is configured in such a way The imaging apparatus according to claim 1.

3. The optical system constitutes a wide-angle lens, The lateral magnification β of the rear lens group is, 0.89＜β＜1 satisfies It is configured in such a way The imaging apparatus according to claim 1.

4. The aforementioned optical system constitutes a telephoto lens, The lateral magnification β of the rear lens group is, 1＜β＜1.23 satisfies It is configured in such a way The imaging apparatus according to claim 1.

5. The rear lens group is fixed to the imaging unit by the lens holding unit. It is configured in such a way The imaging apparatus according to claim 1.

6. The rear lens group and the lens holder are formed integrally by molding resin material or glass. The imaging apparatus according to claim 5.

7. Let TL be the total length of the optical system, and let d be the distance from the object-side surface of the rear lens group to the imaging unit. 0 < d / TL < 0.5 satisfies It is configured in such a way The imaging apparatus according to claim 1.

8. At least one of the plurality of lenses is a cemented lens. It is configured in such a way The imaging apparatus according to claim 1.

9. The outer shape of the aforementioned cemented lens is rectangular. It is configured in such a way The imaging apparatus according to claim 8.

10. The bonded lens is formed by cutting a bonded lens array in which two or more lens arrays are integrally molded without an adhesive layer at at least one bonding interface. The imaging device according to claim 9.

11. The two or more lens arrays include a first lens array and a second lens array. The refractive index of the first lens array is higher than that of the second lens array, and the Abbe number of the first lens array is smaller than that of the second lens array. It is configured in such a way The imaging apparatus according to claim 10.

12. The refractive index of the first lens array is 1.58 or greater, and the Abbe number is less than 35. The refractive index of the second lens array is less than 1.58, and the Abbe number is 35 or greater. It is configured in such a way The imaging apparatus according to claim 11.

13. The plurality of lenses are arranged in the order of the first lens, the second lens, and the cemented lens, from the object side toward the image plane. The first lens, the second lens, and the cemented lens are aspherical lenses. It is configured in such a way The imaging apparatus according to claim 8.

14. The aforementioned plurality of lenses are formed from a resin material. It is configured in such a way The imaging apparatus according to claim 8.

15. The aforementioned group of lenses is composed of the rear lens group and the front lens group, which is a lens other than the rear lens group. At least one of the front lens group and the rear lens group is a lens group with a cemented lens, which is composed of a plurality of lenses including the cemented lens. The aforementioned bonded lens group is formed by stacking the individual lenses that make up the bonded lens group. It is configured in such a way The imaging apparatus according to claim 8.

16. The outer shape of the aforementioned lens group with a cemented lens is rectangular. It is configured in such a way The imaging apparatus according to claim 15.

17. The bonded lens is formed by cutting a bonded lens array in which two or more lens arrays are integrally molded without an adhesive layer at at least one bonding interface. The aforementioned bonded lens group is formed by stacking the bonded lens and the lenses other than the bonded lens that constitute the bonded lens group. The imaging device according to claim 16.

18. The aforementioned bonded lens group is formed by stacking and cutting a bonded lens array in which two or more lens arrays are integrally molded without an adhesive layer at at least one bonding interface, and an array of lenses other than the bonded lens that constitute the bonded lens group. The imaging device according to claim 16.

19. The aforementioned bonded lens group is formed by stacking and cutting a bonded lens array, in which two or more lens arrays are integrally molded without an adhesive layer at at least one bonding interface, and lenses other than the bonded lens that constitute the bonded lens group. The imaging device according to claim 16.

20. A front lens, which is one of the plurality of lenses other than the rear lens, or a drive unit that drives the imaging unit to focus the rear lens to which the rear lens is fixed. Furthermore, it is equipped with The imaging apparatus according to claim 1.

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