JP2022077414A - Lens driving actuator and portable terminal - Google Patents

Abstract

To improve the optical characteristics of a compact portable terminal such as a mobile telephone and a smartphone, while maintaining its thinness.SOLUTION: A lens driving actuator comprises: an upper cover that has an opening through which light passes; a lens barrel 1 that is arranged inside the upper cover and provided therein with a lens transmitting light; a fourth gear 14 that is provided on an outer peripheral part of the lens barrel and moves the lens barrel 1 along an optical axis direction of the lens; a driving source 3 that is provided at a position overlapping the fourth gear 14 in the optical axis direction and supplies a driving force to the fourth gear 14; and a sensor PI2 for detecting the position in the optical axis direction of the lens barrel 1. The sensor PI2 is provided at a position overlapping the driving source 3 in the optical axis direction and on the opposite side of a side where the driving source 3 is arranged with respect to a contact between the lens barrel 4 and the fourth gear 14.SELECTED DRAWING: Figure 7

Description

The present invention relates to an actuator for driving a lens provided as an optical system such as a camera mounted on a mobile terminal, and a mobile terminal represented by a smartphone provided with the actuator.

In a camera mounted on a mobile terminal such as a smartphone, a technique of providing a lens or an aperture on the subject side of an image sensor is known. Patent Document 1 discloses a configuration in which the rotation axis of the motor is arranged in a direction orthogonal to the thickness direction of the housing to make it thinner.

Japanese Unexamined Patent Publication No. 2018-22123

On the other hand, in small mobile terminals such as mobile phones and smartphones, it is required to improve the optical characteristics while maintaining the thinness.

In order to solve the above problems, the lens drive actuator of the present invention includes an upper cover having an opening through which light passes, a lens barrel arranged in the upper cover and provided with a lens that transmits light inside. A gear provided on the outer peripheral portion of the lens barrel to move the lens barrel along the optical axis direction of the lens and a position overlapping the gear in the optical axis direction to supply a driving force to the gear. The lens is provided with a drive source for detecting the position of the lens barrel in the optical axis direction, and the sensor is located at a position overlapping the drive source in the optical axis direction.
It is characterized in that it is provided on the side opposite to the side where the drive source is arranged with respect to the contact point between the lens barrel and the gear.

According to the present invention, it is possible to accurately detect the position of the lens barrel while maintaining the thinness.

It is a perspective view of the lens drive actuator 100 which concerns on this embodiment. It is an exploded perspective view of the smartphone S. It is a front view of a lens drive actuator 100 and a rear view of a lens drive actuator 100. It is a perspective view of the lens drive actuator 100, (a) is a lens extended state, and FIG. 4 (b) is a lens retracted state. It is sectional drawing of the lens drive actuator, (a) is a lens extended state, (b) is a lens retracted state. An exploded perspective view of the lens drive actuator 100 according to the present embodiment is shown. It is a bottom view of the lens drive actuator 100 which concerns on this embodiment. (A) The lens extension state, (b) the lens retracted state, and (c) the gear operating end are shown. It is a figure for demonstrating the operation of the lens drive actuator 100 which concerns on this embodiment. (A) The lens extended state, and FIG. 8 (b) shows the lens retracted state. It is a perspective view which looked at the lens drive actuator 100 which concerns on this embodiment from the lower surface side. It is a partial cross-sectional view which shows the relationship with the leaf spring 7 of the lens barrel 1 which concerns on this embodiment. (A) Lens extension state (b) A state between the lens extension state and the lens retracted state. It is a partial exploded view of the lens barrel 1 which concerns on this embodiment. (A) An exploded perspective view of the lens barrel 1, (b) a cross-sectional view, and (c) a perspective view of a manipulative state.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of the lens drive actuator 100 according to the present embodiment. As shown in FIG. 1, the lens drive actuator 100 is provided on the back side of a mobile terminal such as a smartphone S shown by a dotted line. A sensor unit 200 as an image pickup element is arranged on the front side of the smartphone S with respect to the lens drive actuator 100, and a subject image is formed on the image pickup surface of the image pickup element by a lens arranged inside the lens drive actuator 100.

As shown in FIG. 1, the lens drive actuator 100 moves a lens barrel 1 provided with a lens that transmits light inside by driving a drive source 3 with respect to an upper cover 2 having an opening through which light passes. The lens barrel 1 is projected from the upper cover 2 on the back surface of the smartphone S in FIG. 1 (a) (protruding position) and the position where the lens barrel 1 is housed inside the upper cover 2 on the back surface of FIG. 1 (b) (accommodation position). ) And can be moved. The lens barrel 1 is configured to project and be housed together with the portion indicated by the exterior cover member 2b, and to further project from the exterior cover member 2b at the projecting position. In this embodiment, a stepping motor is used as the drive source 3. When the switching of the position of the lens barrel 1 is completed, the drive of the drive source 3 is cut off. When the lens barrel 1 is in the protruding position, it is used as an imaging position, and imaging is performed by the camera module. When the image is taken by the camera module, the lens in the lens barrel 1 is moved in the optical axis direction by the voice coil motor (hereinafter referred to as VCM) housed in the lens barrel 1, and the focusing operation is performed.

An exterior cover member 1a made of metal is provided on the outer surface of the lens barrel 1, and by subjecting the exterior cover member 1a to a matte treatment or a matting treatment, a favorable impression can be given to the user. The exterior cover member 2b is the same as the exterior cover member 1a.

FIG. 2 shows an exploded perspective view of the smartphone S. A sensor unit 200 is arranged on the front side of the smartphone S with respect to the lens drive actuator 100, receives light transmitted through the lens unit provided in the lens drive actuator 100, and is applied to the image pickup surface of the image pickup element in the sensor unit 200. Image the subject image.

FIG. 3 shows a front view of the lens drive actuator 100 and a rear view of the lens drive actuator 100.

4A and 4B are perspective views of the lens drive actuator 100, FIG. 4A is a lens extension state, and FIG. 4B is a lens retracted state.

5A and 5B are cross-sectional views of the lens drive actuator, FIG. 5A is a lens extension state, and FIG. 5B is a lens retracted state. When the drive source 3 is driven, the driving force is transmitted to the drive cam member 4, and the drive cam member 4 is guided by the cam guide groove provided in the upper cover 2 while rotating around the optical axis direction, so that the drive cam member 4 is guided in the optical axis direction. Move to. The drive cam member 4 is provided with a cam groove 4b, and the lens barrel 1 is further guided in the optical axis direction with respect to the drive cam member 4 by guiding the drive pin 1b (see FIG. 6) to the cam groove 4b. Will be moved to. At that time, a straight ring 5 is provided as a rotation stopper to stop the rotation of the lens barrel 1 around the optical axis direction, and the drive pin 1b of the lens barrel 1 moves in the optical axis direction integrally with the drive cam member 4. The linear motion guide groove 5a (see FIG. 6) is engaged to suppress the rotation of the lens barrel 1. Since the dustproof member 20 is provided so that the lens barrel 1 in the retracted state comes into contact with the lens barrel 1 in the retracted state, it is difficult for dust and dirt to enter the image sensor side during normal use of the mobile terminal.

FIG. 6 shows an exploded perspective view of the lens drive actuator 100 according to the present embodiment. The driving force generated by the drive source 3 is provided on the outer peripheral portion of the drive cam member 4 from the first gear 11 through the drive gear train 10 composed of the second gear 12, the third gear 13, and the fourth gear 14. It is supplied by being transmitted to the drive gear teeth 4a, and as the rotary ring 4 moves while rotating in the optical axis direction, the lens barrel 1 and the linear ring 5 also move in the optical axis direction.

FIG. 7 shows a bottom view (a view seen from the front side of the smartphone S) of the lens drive actuator 100 according to the present embodiment. 7 (a) shows a lens extended state, FIG. 7 (b) shows a lens retracted state, and FIG. 7 (c) shows a state in which the phase plate 15a is in contact with the gear operating end.

The feeding state of FIG. 7A is reached by rotating the drive source 3 in the feeding direction by a predetermined rotation speed (rotation angle) from the lens retracting state of FIG. 7B. In order to detect how much the drive source 3 has been rotated, a shield plate 3b is provided at the tip of the pinion gear 3a, and by detecting this shield plate 3b with the photo interrupter PI1, the rotation speed of the drive source ( The rotation angle) is detected, and the extension amount of the lens barrel 1 is detected.

The drive source 3 is driven in the retractable direction from the state of FIG. 7 (a) to reach the state of FIG. 7 (b). At this time, in order to reliably detect that the lens retracted position has been reached, a phase gear 15 having a phase plate 15a at a position detectable by PI2 is provided. The phase gear 15 meshes with the third gear 13, and the phase plate 15a is provided at a position corresponding to the lens retracted position of the drive cam member 4. The phase plate 15a is configured to mechanically abut when the ejection position and the retracting position exceed a predetermined amount in each of the ejection direction and the retracting direction, so that the lens barrel does not move beyond the predetermined position. If the phase gear 15 is mechanically abutted, it is possible to prevent the parts from falling off by rotating to the built-in phase without increasing the number of parts.

FIG. 8 shows a diagram for explaining the operation of the lens drive actuator 100 according to the present embodiment. FIG. 8A shows a lens extended state, and FIG. 8B shows a lens retracted state. The driving force generated by driving the drive source 3 is transmitted to the drive cam member 4 via the drive gear train 10, and the lens barrel 1 is moved in the optical axis direction. First, when the drive source 3 is driven, the pinion 3a rotates, and the first gear 11 that meshes with the pinion 3a rotates drivenly. The drive is sequentially transmitted to the second gear 12, the third gear 13, and the fourth gear 14, and the drive force is transmitted from the fourth gear 14 to the drive gear teeth 4a of the drive cam member 4, and the drive cam member 4 rotates. do. At this time, the position of the drive cam member 4 in the optical axis direction is different between the lens extension state shown in FIG. 8A and the lens retracted state shown in FIG. 8B. In this way, the drive cam member 4 moves in the optical axis direction while receiving the driving force of the fourth gear 14, and the lens barrel 1 disposed inside is extended from the drive cam member 4 to project the lens barrel 1. Let me. The fourth gear 14 has a gear shape extending in the optical axis direction because it meshes with the drive cam member 4 that moves in the optical axis direction. The fourth gear 14 is longer in the optical axis direction than the first gear 11, the second gear 12, and the third gear 13, and is the longest in the optical axis direction in the drive gear train 10. In order to reduce the thickness, the stepping motor, which is the drive source 3, is provided at a position overlapping the drive gear teeth 4a in the optical axis direction. Further, the photointerruptor PI2, which is a sensor for detecting the position of the lens barrel in the optical axis direction, is located at a position overlapping the drive source 3 in the optical axis direction and with respect to the contact point between the lens barrel 1 and the fourth gear 14. , The side opposite to the side where the drive source 3 is arranged (lower than the contact point between the fourth gear 14 and the drive cam member 4 in FIG. 7) (the fourth gear 14 and the drive cam member 4 in FIG. 7). Since it is provided on the upper side of the contact point), the space in the direction orthogonal to the optical axis direction can be effectively used, and it is easy to reduce the thickness.

FIG. 9 shows a perspective view of the lens drive actuator 100 according to the present embodiment as viewed from the lower surface side (front side of the smartphone S). A leaf spring 7 is provided on the surface of the upper cover 2 facing the drive cam member 4 moving in the optical axis direction and the straight ring 5 in the optical axis direction. With this leaf spring 7, the backlash of the drive cam member 4 in the lens extension state can be performed, that is, the backlash of the lens barrel 1 in the optical axis direction can be performed. FIG. 10A shows a state in which the leaf spring 7 is in contact with the drive cam member 4 in the lens extension state, and FIG. 10B shows a state between the lens extension state and the lens retracted state. The leaf spring 7 is not in contact with the drive cam member 4.

FIG. 11A shows an exploded perspective view of the lens barrel 1. In the present embodiment, three drive pins 1b are provided, but a part of them (one in the present embodiment) is provided as a separate movable guide pin 8a and backlash as shown in FIG. It may be configured with a pulling spring 8b. At this time, the lens barrel 1 is provided with a holding portion 1c for holding the movable guide pin 8a and the backlash spring 8b. As shown in the perspective view of FIG. 11C, the movable guide pin 8a urged outward in the radial direction by the backlash spring 8b penetrates the linear motion guide groove 5a of the linear ring 5. As shown in the cross-sectional view of FIG. 11B, the movable guide pin 8a is engaged with the cam groove 4b of the drive cam member 4, so that the lens barrel 1 can be loosened in the radial direction. ing.

The following configuration may be adopted to solve the problems of looseness and gaps when the drive cam member 4 is configured to move in the optical axis direction.

It is preferable to arrange the dustproof member 20 with which the lens barrel 1 comes into contact with the lens barrel 1 in the retracted state. In this embodiment, an example in which the dustproof member 20 is arranged on the lens drive unit 100 side is shown, but the dustproof member 20 may be provided on the substrate side where the image pickup element is provided so as to surround the periphery of the image pickup element. .. The dustproof member 20 may be made of an elastic body made of resin in order to obtain good adhesion to the retracted state, and may be arranged so as to be slightly recessed from the non-collapsed state.

S Mobile terminal (smartphone)
100 Lens drive actuator 200 Sensor unit 1 Lens tube 1a Exterior cover member 1b Drive pin 1c Holding part 2 Top cover 2b Exterior cover member 2c Cam guide groove 3 Drive source 3a Pinion gear 3b Shielding plate 4 Drive cam member 4b Cam groove 5 Straight ring 5a Linear guide groove 7 Leaf spring 8a Movable guide pin 8b Backlash spring base 10 Drive gear row 11 1st gear 12 2nd gear 13 3rd gear 14 4th gear 15 Phase gear 15a Phase plate 20 Dustproof member PI1 Photo interrupter ( For motor 3)
PI2 photo interrupter (for phase gear 15)

Claims (5)

An upper cover with an opening through which light can pass,
A lens barrel arranged inside the upper cover and provided with a lens that transmits light inside.
A gear provided on the outer peripheral portion of the lens barrel to move the lens barrel along the optical axis direction of the lens.
A drive source provided at a position overlapping the gear in the optical axis direction to supply a driving force to the gear,
A sensor for detecting the position of the lens barrel in the optical axis direction is provided.
The sensor is located at a position overlapping the drive source in the optical axis direction and
A lens drive actuator characterized in that the contact point between the lens barrel and the gear is provided on the side opposite to the side on which the drive source is arranged. The lens-driven actuator according to claim 1, wherein the sensor optically detects the position of another gear directly connected to the gear. The gear is driven from the drive source via a plurality of gears different from the gear.
The lens drive actuator according to claim 1 or 2, wherein the gear is longer in the optical axis direction than the plurality of gears. The lens barrel is connected to the gear and has a drive cam member that moves in the optical axis direction while rotating.
One of claims 1 to 3, wherein a cam groove that engages with the drive cam member is provided, and the drive cam member has a straight ring that travels straight in the optical axis direction as the drive cam member rotates. The lens drive actuator described in. A housing provided with the lens drive actuator according to any one of claims 1 to 4 inside.
An image sensor provided at a position facing the lens is provided.
A portable terminal characterized in that the lens barrel is moved to a position protruding from the housing when an image is taken by the image pickup element.

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