CN113504625A

CN113504625A - Lens driving device

Info

Publication number: CN113504625A
Application number: CN202110293290.3A
Authority: CN
Inventors: 小林孝一
Original assignee: Nidec Copal Corp
Current assignee: Nidec Precision Corp
Priority date: 2020-03-23
Filing date: 2021-03-18
Publication date: 2021-10-15
Also published as: JP2021149041A; JP7460409B2

Abstract

The invention provides a lens driving device which can restrain the thickness along the optical axis direction, can be configured in a thin electronic device, and can deal with the high function of a camera. The lens driving device comprises: a base member; an actuator mounted to the base member; a linear frame that advances and retreats in the optical axis direction using an actuator as a power source; and a mounting frame for determining a reference position for driving the lens by the linear frame, wherein the linear frame is retracted to a first position close to the base member during accommodation, and the linear frame is advanced to a second position away from the base member during driving of the lens.

Description

Lens driving device

Technical Field

The present invention relates to a lens driving device.

Background

The lens driving device is as follows: a lens frame holding a lens (lens barrel) is elastically supported by a base member directly or via another member, and the lens frame is moved in the optical axis direction or in a direction intersecting the optical axis while balancing the thrust and elastic forces of an actuator. AF (auto focus) adjustment and OIS (Optical Image Stabilizer) adjustment are performed by lens driving using an actuator (see, for example, patent document 1).

Patent document 1: japanese patent laid-open publication No. 2019-28288

In recent years, electronic devices such as portable devices generally have a camera function. Electronic devices such as portable electronic devices are becoming thinner, and camera modules arranged in housings of electronic devices and lens driving devices attached to camera modules are required to be reduced in thickness along the optical axis direction in consideration of the accommodation property into the thinned housings.

In contrast, the camera module is required to have high functionality for capturing a high-definition image using a large-sized image capturing element, and if this requirement is satisfied, it is necessary to increase the distance from the imaging surface of the image capturing element to the lens (back focal distance) and to improve the change in lens design. However, as described above, since the thickness of the lens driving device mounted to the camera module disposed in the housing of the electronic device after the reduction in thickness along the optical axis direction is limited, there is a problem that it is difficult to satisfy the demand for increasing the back focal length to capture a high-definition image.

Disclosure of Invention

The present invention has been made to solve the above problems. That is, an object of the present invention is to provide a lens driving device which can be disposed in a thin electronic device while suppressing the thickness in the optical axis direction and which can cope with the high functionality of a camera.

In order to solve the above problems, the lens driving device of the present invention has the following configuration.

The lens driving device of the present invention is characterized by comprising: a base member; an actuator mounted to the base member; a linear movement frame that moves the actuator as a power source in the optical axis direction; and a mounting frame for determining a reference position for driving the lens by the linear frame, wherein the linear frame is retracted to a first position close to the base member during accommodation, and the linear frame is advanced to a second position away from the base member during driving of the lens.

Drawings

Fig. 1 is an exploded perspective view of a lens driving device according to an embodiment of the present invention.

Fig. 2 is a plan view of the lens driving device according to the embodiment of the present invention.

Fig. 3 is a side view of a lens driving device according to an embodiment of the present invention.

Fig. 4 is a perspective view showing a single structure of the base member.

Fig. 5 is a perspective view showing a single structure of the rotating frame.

Fig. 6 is a perspective view showing a single structure of the linear movement frame.

Fig. 7 is a perspective view showing a single structure of the mounting frame.

Fig. 8 is an explanatory view when contained ((a) is a sectional view taken along the line X1-X1 in fig. 2, and (b) is a sectional view taken along the line X2-X2 in fig. 2).

Fig. 9 is an explanatory view when contained (a sectional view taken along line X3-X3 in fig. 2).

Fig. 10 is an explanatory view when contained (a sectional view taken along the line Y1-Y1 in fig. 2).

Fig. 11 is an explanatory view of the lens driving operation (in use) ((a) is a sectional view taken along line X1-X1 in fig. 2, and (b) is a sectional view taken along line X2-X2 in fig. 2).

Fig. 12 is an explanatory view (a cross-sectional view taken along line X3-X3 in fig. 2) when the lens is driven (in use).

Fig. 13 is an explanatory view (a cross-sectional view taken along the line Y1-Y1 in fig. 2) when the lens is driven (in use).

Fig. 14 is an explanatory view of another embodiment ((a) is a sectional view taken along line X1-X1 in fig. 2, and (b) is a sectional view taken along line X2-X2 in fig. 2).

Fig. 15 is an explanatory view of another embodiment ((a) is a sectional view taken along line X1-X1 in fig. 2, and (b) is a sectional view taken along line X2-X2 in fig. 2).

Fig. 16 is an explanatory view of another embodiment ((a) is a sectional view taken along line X1-X1 in fig. 2, and (b) is a sectional view taken along line X2-X2 in fig. 2).

Fig. 17 (a) is an explanatory view of an imaging device having a lens driving device, and fig. 17 (b) is an explanatory view of an electronic apparatus (portable information terminal) having an imaging device.

Description of the reference numerals:

1: a lens driving device for driving the lens to move,

2: base member, 2A: elastomer support, 2a 1: a part to be engaged with the locking part,

2B: gear support portion, 2C: guide shaft support portion, 2D: the edge of the opening is provided with a plurality of grooves,

2E: connection circuit board support portion, 2F: thrust receiving portion, 2P: an opening is formed in the bottom of the container,

3: actuator, 3A: a mounting flange is arranged on the base plate,

4: straight frame, 4A: a part to be engaged with the locking part,

4B: cam abutment portion, 4C: guide hole, 4E: a part to be engaged with the locking part,

5: mounting frame, 5A: opening, 5B: bearing surface, 5C: the guided part is guided to the outside by the guide part,

5D: slit hole, 5E: a part to be engaged with the locking part,

6: rotating frame, 6A: the engaging part is provided with a plurality of engaging parts,

6B: cam, 6B 1: first position, 6B 2: second position, 6B 3: in the third position, the first and second positions are,

6C: engaging projection, 7: bonding member, 8: a support member for supporting the support member, and a support member,

10: lens driving section, 11: drive base section, 12: a connection terminal for connecting the terminal to the external circuit,

13: connection circuit board, 20: a circuit board having a plurality of conductive layers,

21: imaging element, 22: an IR cut-off filter is provided for the IR filter,

23: gear, 24, 25: the elastic body is connected with the elastic body,

24a, 25 a: upper engaging portions, 24b, 25 b: a lower clamping part which is arranged at the lower part of the frame,

26: guide shaft, 27: protection plate, 28: the light-transmitting plate is provided with a light-transmitting plate,

100: imaging device, 200: electronic equipment (Portable information terminal)

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings denote parts having the same functions, and overlapping descriptions in the respective drawings are appropriately omitted. In the following description, "up" refers to the front (light incident) direction of the lens, and "down" refers to the rear (light outgoing) direction of the lens.

As shown in fig. 1 to 3, the lens driving device 1 includes at least a base member 2, an actuator 3, a linear frame 4, and a mounting frame 5. The Z direction in fig. 1 indicates the optical axis direction, i.e., the direction orthogonal to both the X-Y directions.

The base member 2 supports the actuator 3, the rectilinear motion frame 4, and the mounting frame 5. As shown in fig. 4, the base member 2 has an opening 2P in the center, and an opening edge 2D is formed around the opening 2P. A plurality of elastic body support portions 2A are provided around the base member 2 so as to stand along the optical axis direction. An engaged portion 2A1 that engages with an upper engaging portion 24a of a coupling elastic body 24 described later is provided on the elastic body support portion 2A.

Further, a gear support portion 2B is provided around the base member 2, and a gear 23 as a transmission member is rotatably supported by the gear support portion 2B. A guide shaft support portion 2C is provided around the opening 2P on the bottom surface of the base member 2.

A rotating frame 6 is supported on the bottom surface of the base member 2. As shown in fig. 5, the rotating frame 6 is a cylindrical member having a meshing portion 6A provided around the circumference thereof to mesh with the gear 23, and a cam 6B provided on a cylindrical side wall thereof. In the illustrated example, the cam 6B is formed with a cam surface downward, and is formed with a horizontal cam surface close to the base member 2, i.e., a first position 6B1, and a horizontal cam surface far from the base member 2, i.e., a second position 6B2, and is formed with an inclined cam surface from the first position 6B1 to the second position 6B 2. Further, an engagement projection 6C that prevents disengagement in the thrust direction is provided on the side surface of the rotary frame 6 so as to project outward.

The actuator 3 is attached to the base member 2 via the attachment flange 3A via the coupling member 7, transmits a driving force to the gear 23, and rotationally drives the rotating frame 6 via the gear 23. The gear 23 decelerates the rotation of the actuator 3 to rotate the rotating frame 6. The mounting flange 3A covers the gear 23 and also serves as a thrust position restricting member for the gear 23. As the actuator 3, for example, a stepping motor can be used, but the present invention is not limited thereto, and a piezoelectric actuator or the like may be used.

The linear frame 4 is disposed inside the rotating frame 6, and advances and retracts in the optical axis direction using the actuator 3 as a power source. The cam 6B of the rotating frame 6 acts during the forward and backward movement of the linear frame 4. The cam contact portion 4B provided on the side surface of the linear movement frame 4 contacts the cam surface of the cam 6B. The rectilinear frame 4 is biased upward by a coupling elastic body (spring) 24 so that the cam contact portion 4B contacts the cam surface of the cam 6B.

More specifically, the lower engaging portion 24B of the connecting elastic body 24 engages with the engaged portion 4A provided outside the cam abutting portion 4B in the linear movement frame 4, and the upper engaging portion 24A of the connecting elastic body 24 engages with the engaged portion 2A1 of the elastic body supporting portion 2A in the base member 2 above the rotation frame 6. Thereby, the rectilinear frame 4 is urged upward by the elastic force of the coupling elastic body 24, and the cam abutting portion 4B of the rectilinear frame 4 abuts against the downward cam surface of the cam 6B.

As shown in fig. 6, the rectilinear frame 4 has a guide hole 4C therein. A guide shaft 26 is inserted into the guide hole 4C. The lower end portion of the guide shaft 26 is supported by the guide shaft support portion 2C of the base member 2, and the upper end portion is supported by the support member 8 attached to the base member 2 and extending upward.

A mounting frame 5 is disposed inside the rectilinear frame 4. The mounting frame 5 accommodates a lens driving section 10 therein. As shown in fig. 7, a support surface 5B for supporting the lens driving unit 10 is provided inside the mounting frame 5, and an opening 5A for allowing light transmitted through the lens driving unit 10 to pass through is provided in the support surface 5B. A pair of upper and lower guided portions 5C are provided outside the side surface of the mounting frame 5 so as to correspond to the two guide shafts 26, and the guide hole 4C of the rectilinear frame 4 is sandwiched between the pair of upper and lower guided portions 5C.

The lens driving unit 10 housed in the mounting frame 5 is provided with an actuator or the like for driving a lens frame (lens), not shown, in one or both of the optical axis direction and the direction intersecting the optical axis on the driving base unit 11. A connection terminal 12 for supplying power to its actuator is provided on the drive base unit 11 of the lens drive unit 10, and one end side of the connection circuit board 13 is connected to the connection terminal 12. The connection circuit board 13 protrudes from the slit hole 5D of the mounting frame 5, and is supported by the connection circuit board support portion 2E in the base member 2.

A protective plate 27 is provided at the upper end of the rectilinear frame 4, and a light transmitting plate 28 is provided at an opening of the protective plate 27. The light transmitted through the transparent plate 28 is transmitted through the lens of the lens driving unit 10, passes through the opening 5A of the mounting frame 5, passes through the opening 2P of the base member 2, and is incident (imaged) on the imaging surface of the imaging element 21 mounted on the circuit board 20 of the base member 2. An IR cut filter 22 and the like can be provided in front of the imaging element 21 as necessary. The camera module having the lens driving device 1 can be configured by integrally mounting the image pickup device 21 to the base member 2 via the circuit board 20.

The lens driving device 1 rotates the rotating frame 6 on the base member 2 within a predetermined angular range around a rotation axis along the optical axis by driving the actuator 3. The engaging projection 6C of the rotating frame 6 projects from the side surface to the outside, and the engaging projection 6C engages with the thrust receiving portion 2F of the base member 2 to prevent the rotating frame 6 from coming off in the thrust direction.

When the rotating frame 6 rotates, the rectilinear frame 4 moves forward and backward in the optical axis direction along the guide shaft 26 by the cam surface of the cam 6B abutting against the cam abutting portion 4B of the rectilinear frame 4. The actuator 3 rotates the rotary frame 6 as described above, but since both the rectilinear frame 4 in the rotary frame 6 and the attachment frame 5 in the rectilinear frame 4 engage the guide shaft 26 supported by the base member 2, the movement in the rotational direction is prevented by the guide shaft 26, and only the movement in the optical axis direction along the guide shaft 26 is possible.

Fig. 8 shows the accommodated state of the lens driving section 10. At this time, the cam abutting portion 4B of the rectilinear frame 4 abuts on the first position 6B1 of the cam 6B in the rotary frame 6. The rectilinear frame 4 is biased upward by the elastic force of the coupling elastic body 24, but the upward movement thereof is restricted by the first position 6B1 of the cam 6B, and the rectilinear frame 4 is held in the accommodated state.

In this accommodated state, as shown in fig. 9, the upper surface of the guide shaft support portion 2C of the base member 2 abuts against the lower surface of the guided portion 5C of the mounting frame 5, and the mounting frame 5 cannot move further downward. Thus, when the cam abutting portion 4B of the rectilinear frame 4 abuts the first position 6B1 of the cam 6B in the rotary frame 6, the mounting frame 5 is retracted to a position where contact with the base member 2 is avoided.

At this time, the mounting frame 5 is coupled to the rectilinear frame 4 via the coupling elastic body 25, the upper engaging portion 25a of the coupling elastic body 25 is engaged with the engaged portion 5E of the mounting frame 5, and the lower engaging portion 25b of the coupling elastic body 25 is engaged with the engaged portion 4E of the rectilinear frame 4. Therefore, when the guided portion 5C of the mounting frame 5 abuts on the upper surface of the guide shaft support portion 2C, the coupling elastic body 25 contracts, and the mounting frame 5 moves relative to the rectilinear frame 4.

Fig. 11 shows a state of the lens driving unit 10 at the time of lens driving (at the time of use). At this time, the cam abutting portion 4B of the rectilinear frame 4 abuts on the second position 6B2 of the cam 6B in the rotary frame 6. The rectilinear frame 4 is biased upward by the elastic force of the coupling elastic body 24, but is kept in the use state by being restricted from moving upward by the second position 6B2 of the cam 6.

In this use state, as shown in fig. 12 and 13, the lower surface of the guided portion 5C of the mounting frame 5 is separated from the upper surface of the guide shaft support portion 2C in the base member 2, and the guide hole 4C of the linear movement frame 4 sandwiched between the pair of guided portions 5C is biased upward of the pair of guided portions 5C by the coupling elastic body 25. Thus, after the lower surface of the guided portion 5C of the mounting frame 5 is separated from the upper surface of the guide shaft support portion 2C, the mounting frame 5 moves along the guide shaft 26 integrally with the rectilinear frame 4.

In this use state, the rectilinear frame 4 projects upward relative to the rotary frame 6, and the lens driving unit 10 accommodated in the mounting frame 5 held by the rectilinear frame 4 can secure a sufficient distance from the imaging surface of the imaging element 21 mounted on the circuit board 20 of the base member 2.

The lens driving device 1 includes a mounting frame 5, and the mounting frame 5 moves the rectilinear frame 4 forward and backward in the optical axis direction using the actuator 3 mounted to the base member 2 as a power source, and determines a reference position for driving the lens by the rectilinear frame 4. Thus, when not in use, the mounting frame 5 can be retracted with respect to the optical axis, and the total thickness of the lens drive device 1 when housed can be reduced.

In use for lens driving, the straight-moving frame 4 is moved in the optical axis direction to increase the distance between the lens driving unit 10 and the imaging element 21 supported by the base member 2, thereby increasing the back focal length of the lens. This can improve the change in lens design in the lens driving unit 10, and can capture a high-definition image.

Since the lens driving unit 10 that drives the lens in one or both of the optical axis direction and the direction intersecting the optical axis is disposed in the mounting frame 5 and the lens driving unit 10 can drive the lens at a predetermined position of the mounting frame 5, the lens position can be driven in the optical axis direction by the movement of the mounting frame 5 in addition to the fine lens movement of the lens driving unit 10 alone.

Further, since the mounting frame 5 is coupled to the rectilinear frame 4 via the coupling elastic body 25 and the rectilinear frame 4 is coupled to the rotary frame 6 via the coupling elastic body 24, the vibration between the members is eliminated by the coupling

elastic members

24 and 25, and further, when external pressure toward the base member 2 acts on the rectilinear frame 4 and the mounting frame 5 in a state where the rectilinear frame 4 and the mounting frame 5 are separated from the base member 2, the rectilinear frame 4 and the mounting frame 5 are elastically retracted with respect to the external pressure, and damage of the lens driving unit 10 and the like with respect to the external pressure can be suppressed.

At this time, when the mounting frame 5 coupled to the rectilinear frame 4 approaches the base member 2, the mounting frame comes into contact with the upper surface of the guide shaft support portion 2C as the projection of the base member 2 and stops, so that even when external pressure toward the base member 2 is applied to the rectilinear frame 4 and the mounting frame 5, the collision with the imaging element 21 can be avoided.

Fig. 14 to 16 show other embodiments of the present invention. In the lens driving device 1 of this embodiment, the rectilinear frame 4 can be moved to the third position 6B3 further away from the base member 2 with respect to the second position 6B2, and the lens driving unit 10 is disposed in the mounting frame 5 in which the reference position for lens driving is determined by the rectilinear frame 4, and the lens driving unit 10 drives at least the lens to be movable in the optical axis direction. Then, the lens position is adjusted by the movement of the linear frame 4 in the optical axis direction by the actuator 3 and the lens driving in the optical axis direction by the lens driving unit 10.

The adjustment of the lens position at this time can be performed from the storage position shown in fig. 14 to the first use position shown in fig. 15, and further can be performed to the third use position shown in fig. 16. The lens adjustment here may be one or both of focus adjustment and zoom adjustment.

In the third use position, the position adjustment range of the lens by the lens driving unit 10 is made smaller than the position adjustment range of the lens by the actuator 3, and the infinity focus position is set to be out of the lens operable range in the lens driving unit 10 in a state where the mounting frame 5 is farthest from the base member 2 by the actuator 3, whereby the lens driving for macro (close/close) photographing is enabled.

In such lens position adjustment, a detection unit for detecting the lens position is provided in the lens driving unit 10 accommodated in the mounting frame 5, and the lens position adjustment can be performed by adding the movement amount of the rectilinear frame 4 by the actuator 3 to the detection result of the lens position in the lens driving unit 10. Alternatively, a detection unit that detects the position of the mounting frame 5 in the optical axis direction may be provided, and the lens position adjustment may be performed by adding the detection result of the lens position in the lens driving unit 10 and the detection result of the position of the mounting frame 5 in the optical axis direction.

For lens adjustment in the lens driving unit 10, a Voice Coil Motor (VCM) or the like can be used. In addition, a lens driving mechanism for correcting camera shake may be provided in addition to the focus adjustment in the optical axis direction in the lens adjustment of the lens driving unit 10.

In the example shown in fig. 14 to 16, horizontal surfaces are provided at the second position 6B2 and the third position 6B3 of the cam 6B, and the positions of these two positions are used to stop the position of the mounting frame 5 in the optical axis direction during use. Further, the lens position adjustment in the lens driving unit 10 can be performed by using the positions of these two portions. Here, the optical axis direction position of the mounting frame 5 is stopped at two locations during use, but three or more stop positions may be provided.

In the lens position adjustment at this time, for example, the lens position is roughly adjusted by the movement of the mounting frame 5 by the actuator 3, and after the mounting frame 5 stops at the second position 6B2 or the third position 6B3, fine adjustment by the lens driving unit 10 is performed. At this time, when the latching portion that fits into the recess of the cam abutting portion 4B is provided at the horizontal position of the second position 6B2 or the third position 6B3, and the cam abutting portion 4B is latched in a state in which it can be disengaged by the force of the actuator 3, the mounting frame 5 can be stopped in a state in which the actuator 3 is not energized by latching the latching portion 4B to the above-described latching portion, and power saving can be achieved in driving the lens.

In the above description, the mounting frame 5 is stopped at the horizontal position of the cam 6B by way of example, but the mounting frame 5 can be stopped even at an arbitrary inclined position of the cam 6B, and the function of adjusting the lens position can be enhanced. At this time, if the rectilinear motion frame 4 can be held at an arbitrary position by the non-energization holding torque of the actuator 3, the mounting frame 5 in the non-energized state can be held, and the power saving driving can be realized, but the position of the mounting frame 5 may be held by the energization holding torque of the actuator 3.

Fig. 17 shows an imaging device (camera unit) 100 (see fig. 17 a) having the lens driving device 1, and an electronic apparatus 200 (see fig. 17B) or a portable information terminal having the imaging device 100. Such an imaging device 100 or electronic apparatus 200 can mount a camera unit having the high-performance lens driving device 1 on a thin body.

While the embodiments of the present invention have been described in detail with reference to the drawings, the specific configurations are not limited to these embodiments, and modifications of design and the like within a range not departing from the gist of the present invention are also included in the present invention. In addition, the above-described embodiments can be combined with each other as long as the objects, structures, and the like are not particularly contradictory or problematic.

Claims

1. A lens driving device is characterized in that,

comprising:

a base member;

an actuator mounted to the base member;

a linear movement frame that moves forward and backward in the optical axis direction using the actuator as a power source; and

a mounting frame for determining a reference position for driving the lens by the straight frame,

when the lens is accommodated, the linear frame is retracted to a first position close to the base member, and when the lens is driven, the linear frame is advanced to a second position away from the base member.

2. The lens driving apparatus as claimed in claim 1,

when the straight-moving frame is located at the first position, the mounting frame is retracted to a position where contact with the base member is avoided.

3. The lens driving apparatus as claimed in claim 1,

a rotating frame supported by the base member and rotated about a rotation axis along an optical axis by the actuator,

the linear frame advances and retreats in the optical axis direction through a cam provided in the rotating frame.

4. The lens driving apparatus according to claim 2,

5. The lens driving apparatus as claimed in claim 1,

the linear movement frame is capable of traveling to a third position that is farther from the base member than the second position,

a lens driving unit that drives at least the lens to be movable in the optical axis direction is disposed in a mounting frame that determines a reference position for driving the lens by the rectilinear frame,

the lens position is adjusted by the movement of the linear frame in the optical axis direction by the actuator and the lens driving in the optical axis direction by the lens driving unit.

6. The lens driving apparatus as claimed in claim 5,

in a state where the mounting frame is farthest from the base member by the actuator, an infinite focus position is out of a lens operable range in the lens driving unit.

7. An imaging device having the lens driving device according to any one of claims 1 to 6.