CN115933106A

CN115933106A - Method for Determining Driving Frequency of Lens Driving Device

Info

Publication number: CN115933106A
Application number: CN202310062526.1A
Authority: CN
Inventors: 赵一玮
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-01-20
Filing date: 2023-01-20
Publication date: 2023-04-07

Abstract

The invention discloses a method for determining the driving frequency of a lens driving device, wherein the lens driving device is driven by a piezoelectric mechanism, and the method comprises the following steps: step one, calculating the shearing strain of the piezoelectric element; secondly, converting the shear strain into the horizontal movement amount of the piezoelectric element; step three, calculating the total displacement; and step four, calculate the said driving frequency from the said total displacement. The method for determining the driving frequency of the lens driving device is simple and easy to implement, high in implementability and strong in operability.

Description

Method for determining driving frequency of lens driving device

Technical Field

The invention relates to the field of optical imaging, in particular to a method for determining the driving frequency of a lens driving mechanism.

Background

The motor of the geared lens driving device is typically mounted within the camera module of the mobile phone and is typically driven by an electromagnetic combination of magnets and coils, which generate a magnetic field that interferes with other electronic components such as the interior of the mobile phone. In addition, the suspension wires, the reeds and the like are usually adopted for assistance, and the irreversible deformation problems such as metal fatigue and metal deformation can be caused after the metal fatigue is suffered from impact.

Disclosure of Invention

An object of the present invention is to provide a method for determining a driving frequency of a lens driving apparatus, so as to solve the above-mentioned problems in the prior art.

In order to solve the above-mentioned problems, according to a first aspect of the present invention, there is provided a driving frequency determining method of a lens driving device which is driven by a piezoelectric mechanism, the method comprising the steps of:

the method comprises the following steps: calculating the shear strain of the piezoelectric element;

step two: converting the shear strain into a horizontal movement amount of a piezoelectric element;

step three: calculating the total displacement;

step four: calculating the driving frequency from the total displacement amount.

In one embodiment, in the first step, the shear strain S of the piezoelectric element is calculated by the following formula:

S＝d ₁₅ x E, where S is shear strain, E is electric field strength, d ₁₅ Is a parameter of the piezoelectric material.

In one embodiment, in the first step, the electric field strength E is calculated by the following formula:

E＝V/L _x where V is the voltage, L _x Is the piezoelectric thickness.

In one embodiment, in the second step, the amount of horizontal movement of the piezoelectric element is calculated using the following formula:

Δ X = R × S, where R is the piezoelectric to bump distance and S is the shear strain, which is the camber value.

In one embodiment, in the third step, the total displacement is calculated by the following formula:

S _{general (1)} =2 × Δ X, wherein S _{General (1)} Δ X is the amount of horizontal movement of the piezoelectric element as the total displacement amount.

In one embodiment, in the fourth step, the total displacement S is determined by the following formula _{General (1)} And calculating a driving frequency f, f = V/S for the moving distance V per second _{General assembly} 。

In one embodiment, the piezoelectric element of the lens driving mechanism is an n-layer laminated mechanism, and in the third step, the total displacement S _{General (1)} ＝2×ΔX×n。

The lens driving device has the advantages that the lens driving device drives the lens to move along the optical axis direction by utilizing the piezoelectric driving principle, the traditional electromagnetic driving mode is abandoned, the zooming function of the lens is realized, and the dual driving mode enables the zooming function of the lens to be more sensitive, flexible and accurate.

Drawings

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

fig. 2 is a sectional view of the lens driving apparatus of fig. 1 with a housing removed;

fig. 3 is an exploded perspective view of the lens driving apparatus of fig. 1 in a direction a with the housing and the dust cap removed;

fig. 4 is an exploded perspective view of the lens driving apparatus of fig. 1 in a direction B with the housing and the dust cover removed;

fig. 5 is a dust cap in the lens driving apparatus of fig. 1.

Fig. 6 is a flow chart of a method for determining a driving frequency of a lens driving apparatus according to an embodiment of the present invention.

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that the objects, features and advantages of the invention can be more clearly understood. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the present invention, but are merely intended to illustrate the essential spirit of the technical solution of the present invention.

In the following description, for the purposes of illustrating various disclosed embodiments, certain specific details are set forth in order to provide a thorough understanding of the various disclosed embodiments. One skilled in the relevant art will recognize, however, that the embodiments may be practiced without one or more of the specific details. In other instances, well-known devices, structures and techniques associated with this application may not be shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

In the following description, for the purposes of clearly illustrating the structure and operation of the present invention, directional terms will be used, but terms such as "front", "rear", "left", "right", "outer", "inner", "outer", "inward", "upper", "lower", etc. should be construed as words of convenience and should not be construed as limiting terms.

Referring to fig. 2, the lens driving apparatus 1000 includes a base 500, a first carrier 100, and a first piezoelectric mechanism 300, the base 500 is provided with a first chamber 510, the first carrier 100 is disposed in the first chamber 510, and the first piezoelectric mechanism 300 drives the first carrier 100 to move along an optical axis direction.

The base 500 is provided with a first chamber 510, the first carrier 100 is disposed in the first chamber 510 and provided with a second chamber 110, the second carrier 200 is disposed in the second chamber 110 and used for mounting a lens, the first piezoelectric mechanism 300 is disposed between the base 500 and the first carrier 100 and configured to drive the first carrier 100 to move along the optical axis direction relative to the base 500, the second piezoelectric mechanism 400 is disposed between the second carrier 200 and the first carrier 100 and configured to drive the second carrier 200 to move along the optical axis direction relative to the first carrier 100, wherein when the first piezoelectric mechanism 300 drives the first carrier 100 to move along the optical axis direction, the first carrier 100 drives the second carrier 200 mounted in the second chamber 110 to move along the optical axis direction, so that the second carrier 200 is indirectly and directly driven by the first piezoelectric mechanism 300 and the second piezoelectric mechanism 400 to drive the lens mounted in the second carrier 200 to move along the optical axis direction to realize the zoom operation of the lens.

Through such design, first piezoelectric mechanism 300 and second piezoelectric mechanism 400 utilize the piezoelectricity drive principle drive first carrier 100 and second carrier 200 to move along the optical axis direction, have abandoned traditional electromagnetic drive mode, realize the function of zooming of camera lens, and dual drive mode makes the function of zooming of camera lens more sensitive, more nimble, more accurate.

It should be noted that:

first, the optical axis direction refers to the optical axis direction of the lens, the first piezoelectric mechanism 300 drives the first carrier 100 to move along the optical axis in a single direction, and also to reciprocate along the optical axis in two directions, and the second piezoelectric mechanism 400 drives the second carrier 200 to move along the optical axis in a single direction, and also to reciprocate along the optical axis in two directions.

Second, the first carrier 100 is disposed in the base 500, the second carrier 200 is disposed in the first carrier 100, the lens is disposed in the second carrier 200, the first carrier 100 and the second carrier 200 can respectively drive the lens to move along the optical axis direction, and the first carrier 100 and the second carrier 200 can also simultaneously drive the lens to move along the optical axis direction.

In an embodiment of the present invention, referring to fig. 3 and 4, the first piezoelectric mechanism 300 includes a first piezoelectric element 301, a first friction member 302, and a first friction fitting 303, the first piezoelectric element 301 is mounted on the base 500, the first friction fitting 303 is fixedly mounted on the first carrier 100 and abuts against one end of the first friction member 302 to be in friction fit with the first friction member 302, the other end of the first friction member 302 is fitted with the first piezoelectric element 301, and when the first piezoelectric element 301 is powered on, the first piezoelectric element 301 drives the first friction member 302 and the first friction fitting 303 to move so as to drive the first carrier 100 to move along the optical axis direction.

Specifically, referring to fig. 3 and 4, the first piezoelectric element 301 is mounted in the first piezoelectric element mounting groove 501 of the base 500, the first friction fitting piece 303 is mounted in the first friction fitting piece mounting groove 101 of the side wall of the first carrier 100, and abuts against one end of the first friction piece 302 to be in friction fitting with the first friction piece 302, and the other end of the first friction piece 302 is fixedly connected with the first piezoelectric element 301, so that when the first piezoelectric element 301 is powered on, the first piezoelectric element 301 drives the first friction piece 302 and the first friction fitting piece 303 to move, thereby driving the first carrier 100 to move in the optical axis direction.

Through such a design, the first piezoelectric element 301 generates a change in shape when being powered on, and by adjusting the frequency of the power current, the outer diameter of the first piezoelectric element 301 changes rapidly, which causes the first friction member 302 fixedly connected thereto to vibrate continuously, and since the first friction member 302 abuts against the first friction fitting member 303, that is, there is a force effect between the first friction member 302 and the first friction fitting member 303, the vibration of the first friction member 302 drives the first friction fitting member 303 to move, thereby driving the first carrier 100 to move along the optical axis direction.

Alternatively, the driving frequency, i.e. the frequency of the current after the energization, may be determined by the following method, referring to fig. 6, which mainly includes the following steps:

step S10: calculating the shear strain of the piezoelectric element;

step S20: converting the shear strain into a horizontal movement amount of a piezoelectric element;

step S30: calculating the total displacement;

step S40: calculating the driving frequency from the total displacement amount.

Alternatively, in the step S10, the shear strain S of the piezoelectric element is calculated by the following formula:

S＝d ₁₅ x E, where S is shear strain, E is electric field strength, d ₁₅ Is a parameter of the piezoelectric material itself, and is determined by the properties of the piezoelectric material.

Alternatively, the electric field strength E is calculated by the following formula: e = V/L _x Wherein V is voltage, L _x Is the piezoelectric thickness.

For example, in certain embodiments, d15=741 x 10 ^-12 Voltage V =5V, piezoelectric thickness L _x Electric field E = 5/(0.5 × 10) when =0.5mm ^-3 )＝10 ⁴ ，S＝7410×10 ^-9 。

Alternatively, in the step S20, the amount of horizontal movement of the piezoelectric element is calculated using the following formula:

Δ X = R × S, where R is the piezoelectric to bump distance and S is the shear strain, which is an arc value.

For example, in certain embodiments, d15=741 x 10 ^-12 Voltage V =5V, piezoelectric thickness L _x Electric field E = 5/(0.5 × 10) when =0.5mm ^-3 )＝10 ⁴ ，S＝7410×10 ^-9 When the piezoelectric-to-bump distance R =0.9mm, Δ X =0.9 × 10 ^-3 ×7410×10 ^-9 ＝6.67×10 ^-9 (m)＝6.67(nm)。

Optionally, in the step S30, the total displacement S _{General (1)} ＝2×ΔX。

For example, d15=741 × 10 ^-12 Voltage V =5V, piezoelectric thickness L _x Electric field E = 5/(0.5 × 10) when =0.5mm ^-3 )＝10 ⁴ ，S＝7410×10 ^-9 When the piezoelectric-to-bump distance R =0.9mm, Δ X =0.9 × 10 ^-3 ×7410×10 ^-9 ＝6.67×10 ^-9 (m)＝6.67(nm)，S _{General (1)} ＝2×ΔX＝2×6.67＝13.33nm。

Optionally, in the step S40, according to the total displacement S _{General assembly} And the moving distance V of each second, i.e. f = V/S _{General (1)} 。

For example, d15=741 × 10 ^-12 Voltage V =5V, piezoelectric thickness L _x Electric field E = 5/(0.5 × 10) when =0.5mm ^-3 )＝10 ⁴ ，S＝7410×10 ^-9 When the piezoelectric-to-bump distance R =0.9mm and the moving speed reaches 15mm/s, Δ X =0.9 × 10 ^-3 ×7410×10 ^-9 ＝6.67×10 ^-9 (m)＝6.67(nm)，S _{General assembly} ＝2×ΔX＝2×6.67＝13.33nm，f＝15/13.33＝1.124MHz。

As can be seen from the above method, if it is necessary to increase the total displacement amount, the piezoelectric may be made to have a laminated structure, and thus the thickness of the piezoelectric is reduced and the number of laminated layers is increased, for example, in the following embodiment, d15=741 × 10 ^-12 Voltage V =5V, piezoelectric thickness L _x =0.5mm and the piezo-electric distance R =0.9mm. If the piezoelectric is of a laminated structure, the thickness of the piezoelectric is reduced, the number of piezoelectric layers is increased, for example, the thickness of the piezoelectric layer is 0.15mm, and if a three-layer laminated structure is adopted, the total displacement is increased by 10 times and is 133nn, which is basically the total displacement of the piezoelectric actuator than most of the piezoelectric actuators at presentIs large.

Therefore, for such an n-layer stacking mechanism, in the step S30, the total displacement S _{General (1)} ＝2×ΔX×n。

In an embodiment of the invention, referring to fig. 3 and 4, the first piezoelectric mechanism 300 further includes a first elastic sheet 304, and the first elastic sheet 304 is mounted on the base 500 and abuts against the first piezoelectric element 301 to apply an elastic force to the first piezoelectric element 301 in a direction toward the first friction fitting 303.

Specifically, referring to fig. 3 and 4, the first resilient piece 304 is mounted in a first resilient piece mounting groove 502 of a side wall of the base 500, and abuts against the first piezoelectric element 301 to apply a resilient force to the first piezoelectric element 301 in a direction toward the first friction fit piece 303.

Through the design, the first elastic sheet 304 has certain elasticity, and is abutted against the first piezoelectric element 301, that is, the first elastic sheet 304 has a force effect on the first piezoelectric element 301, so that the first elastic sheet 304 presses the first piezoelectric element 301 towards the first friction fitting piece 303, and because the first piezoelectric element 301 is fixedly connected with one end of the first friction piece 302, the friction force between the first friction piece 302 and the first friction fitting piece 303 is increased, and the driving effect of the first piezoelectric mechanism 300 is improved.

In one embodiment of the present invention, referring to fig. 3 and 4, the second piezoelectric mechanism 400 includes a second piezoelectric element 401, a second friction member 402, and a second friction fitting 403, the second piezoelectric element 401 is mounted on the first carrier 100, the second friction fitting 403 is fixedly mounted on the second carrier 200 and abuts against one end of the second friction member 402 to be in friction fit with the second friction member 402, the other end of the second friction member 402 is fitted with the second piezoelectric element 401, and when the second piezoelectric element 401 is powered on, the second piezoelectric element 401 drives the second friction member 402 and the second friction fitting 403 to move so as to drive the second carrier 200 to move along the optical axis direction.

Specifically, referring to fig. 3 and 4, a second piezoelectric element 401 is mounted in the second piezoelectric element mounting groove 102 of the first carrier 100, a second friction fitting piece 403 is mounted in the second friction fitting piece mounting groove 201 of the side wall of the second carrier 200, and abuts against one end of the second friction piece 402 to be in friction fitting with the second friction piece 402, and the other end of the second friction piece 402 is fixedly connected with the second piezoelectric element 401, so that when the second piezoelectric element 401 is powered on, the second piezoelectric element 401 drives the second friction piece 402 and the second friction fitting piece 403 to move, thereby driving the second carrier 200 to move along the optical axis direction.

By such a design, the shape of the second piezoelectric element 401 changes when the second piezoelectric element is energized, and by adjusting the frequency of the energizing current, the outer diameter of the second piezoelectric element 401 changes rapidly, which causes the second friction element 402 fixedly connected with the second piezoelectric element to vibrate continuously, and because the second friction element 402 abuts against the second friction fitting 403, that is, there is a force effect between the second friction element 402 and the second friction fitting 403, the vibration of the second friction element 402 drives the second friction fitting 403 to move, thereby driving the second carrier 200 to move along the optical axis direction.

In an embodiment of the invention, referring to fig. 3 and 4, the second piezoelectric mechanism 400 further includes a second elastic sheet 404, and the second elastic sheet 404 is mounted on the first carrier 100 and abuts against the second piezoelectric element 401 to apply an elastic force to the second piezoelectric element 401 in a direction toward the second friction fitting 403.

Specifically, referring to fig. 3 and 4, the second elastic piece 404 is mounted to the first elastic piece mounting groove 103 of the side wall of the first carrier 100, and abuts against the second piezoelectric element 401 to press the second piezoelectric element 401 toward the first friction fitting 403.

Through such a design, the second elastic sheet 404 has a certain elasticity, and abuts against the second piezoelectric element 401, that is, the second elastic sheet 404 and the second piezoelectric element 401 have a force effect, so that the second elastic sheet 404 presses the second piezoelectric element 401 towards the second friction fitting 403, and because the second piezoelectric element 401 and one end of the second friction piece 402 are fixedly connected, the friction force between the second friction piece 402 and the second friction fitting 403 is increased, thereby improving the driving effect of the second piezoelectric mechanism 400.

In one embodiment of the present invention, referring to fig. 3 and 4, the base includes a first sidewall 520 and a third sidewall 540 opposite to each other and a second sidewall 530 disposed between the first sidewall 520 and the third sidewall 540, the first carrier 100 includes a fourth sidewall 120 opposite to the third sidewall 540 of the base 500 and a fifth sidewall 130 opposite to the fourth sidewall 120, and the second carrier 200 includes a sixth sidewall 210 opposite to the fourth sidewall 120 of the first carrier 100 and a seventh sidewall 220 opposite to the sixth sidewall 210.

In one embodiment of the present invention, referring to fig. 3 and 4, when the first carrier 100 is mounted in the first cavity 510 of the base 500 and the second carrier 200 is mounted in the second cavity 110 of the first carrier 100, the first piezoelectric mechanism 300 and the second piezoelectric mechanism 400 are disposed to be opposite to each other.

Specifically, the first piezoelectric element mounting groove 501 and the first spring plate mounting groove 502 are disposed on the first sidewall 520, the first friction fit piece mounting groove 101 is disposed on the fifth sidewall 130, the second piezoelectric element mounting groove 102 and the second spring plate mounting groove 103 are disposed on the fourth sidewall 120, and the second friction fit piece mounting groove 201 is disposed on the sixth sidewall 210.

By such a design, space is saved, and movement of the first and

second carriers

100 and 200 in the optical axis direction is facilitated to be more stable.

In an embodiment of the present invention, referring to fig. 3 and 4, the lens driving apparatus further includes a first guide mechanism 600 and a second guide mechanism 700, the base 500 is movably connected to the first carrier 100 through the first guide mechanism 500, the first carrier 100 moves in the optical axis direction under the guidance of the first guide mechanism 300, and the first carrier 100 is movably connected to the second carrier 200 through the second guide mechanism 700, and the second carrier 200 moves in the optical axis direction under the guidance of the second guide mechanism 400.

With such a design, the first guide mechanism 600 not only reduces the friction resistance when the first carrier 100 moves relative to the base 500, but also guides the movement of the first carrier 100 relative to the base 500. And, the second guide mechanism 700 may not only reduce the frictional resistance when the second carrier 200 moves with respect to the first carrier 100, but also guide the movement of the second carrier 200 with respect to the first carrier 100.

In an embodiment of the present invention, referring to fig. 3 and 4, the first guide mechanism 600 includes a first ball 601, a first ball groove 602, and a first slide groove 603, the first ball groove 602 and the first slide groove 603 are respectively disposed on an inner side surface of the first chamber 510 and an outer side surface of the first carrier 100, the first ball 601 is mounted in the first ball groove 602 and slidably engaged with the first slide groove 603 to move the first carrier 100 in the optical axis direction, or the first ball groove 602 and the first slide groove 603 are respectively disposed on the outer side surface of the first carrier 100 and the inner side surface of the first chamber 510, and the first ball 601 is mounted in the first ball groove 602 and slidably engaged with the first slide groove 603 to move the first carrier 100 in the optical axis direction.

In one embodiment of the present invention, referring to fig. 3 and 4, the second guide mechanism 700 includes a second ball 701, a second ball groove 702, and a second runner 703, the second ball groove 702 and the second runner 703 are respectively disposed on the inner side surface of the second chamber 110 and the outer side surface of the second carrier 200, the second ball 701 is mounted in the second ball groove 702 and slidably engaged with the second runner 703 to move the second carrier 200 in the optical axis direction, or the second ball groove 702 and the second runner 703 are respectively disposed on the outer side surface of the second carrier 200 and the inner side surface of the second chamber 110, and the second ball 701 is mounted in the second ball groove 702 and slidably engaged with the second runner 703 to move the second carrier 200 in the optical axis direction.

In one embodiment of the present invention, referring to fig. 3 and 4, the first guide mechanism 600 includes a plurality of first balls 601 and a plurality of first ball grooves 602, the plurality of first ball grooves 602 are arranged in a row along the optical axis direction, one first ball 601 is disposed in each first ball groove 602, and the plurality of first balls 601 are slidably engaged with the first sliding grooves 603 to move the first carrier 100 along the optical axis direction; and, the second guide mechanism 700 includes a plurality of second balls 701 and a plurality of second ball grooves 702, the plurality of second ball grooves 702 are arranged in a line in the optical axis direction, one second ball 701 is disposed in each second ball groove 702, and the plurality of second balls 701 slidably cooperate with the second slide groove 703 to move the second carrier 200 in the optical axis direction.

In one embodiment of the present invention, referring to fig. 3 and 4, one or more first guide mechanisms 600 may be provided, and in this embodiment, two first guide mechanisms 600 are provided between the base 500 and the outer surface of the first sidewall 120 of the first carrier 100; one or more second guide mechanisms 700 may be provided, and in the present embodiment, two second guide mechanisms 700 are provided, and two second guide mechanisms 700 are provided between the inner surface of the second side wall 130 of the first carrier 100 and the second carrier 200.

By such a design, the first carrier 100 or the second carrier 200 is more stable to move along the optical axis.

In one embodiment of the present invention, referring to fig. 3 and 4, a position sensor 503 and a corresponding induction magnet 504 are provided in the optical axis direction to detect the displacement of the first carrier 100 and/or the second carrier 200 in the optical axis direction.

Specifically, the inner side wall of the first carrier 100 is provided with a position sensor 503, the outer side wall of the second carrier 200 is provided with a sensing magnet 504, and the position sensor 503 and the sensing magnet 504 cooperate to detect the moving position of the second carrier 200, thereby detecting the moving position of the lens.

It is understood that the displacement of the first carrier 100 and/or the second carrier 200 in the optical axis direction can be detected by adjusting the number and positions of the position sensors 503 and the sense magnets 504.

In an embodiment of the present invention, referring to fig. 1, 3 and 4, the lens driving apparatus 1000 further includes a circuit board 800, the circuit board 800 is mounted on the base 500, the circuit board 800 includes a first piezoelectric mechanism connecting unit 801 electrically connected to the first piezoelectric mechanism 300, a second piezoelectric mechanism connecting unit 802 electrically connected to the second piezoelectric mechanism 400, and an extension 803 connecting the first piezoelectric mechanism connecting unit 801 and the second piezoelectric mechanism connecting unit 802, the extension 803 is disposed around the base 500 and mounted in a circuit board mounting groove 506 on an outer sidewall of the base 500.

Specifically, the circuit board 800 is preferably a flexible wiring board (FPC board).

Through the design, the lens driving device is simple in structure and convenient to produce.

In one embodiment of the present invention, referring to fig. 3 and 4, the extension 803 includes a first portion 8032, a second portion 8033, and a third portion 8034, the first portion 8032 and the third portion 8034 are respectively mounted to outer sidewalls of first and

third sidewalls

520 and 540 of the base 500 opposite to each other and are respectively connected to the first and second piezoelectric

mechanism connection units

801 and 802, the second portion 8033 is disposed on an outer sidewall of the second sidewall 530 between the first and

third sidewalls

520 and 540 of the base 500,

in an embodiment of the present invention, referring to fig. 3 and 4, the extension 803 further includes an elastic member 8031, the elastic member 8031 forms a 180-degree bending structure as a whole and includes an outer elastic member 80311 disposed on an outer surface of the base 500 and an inner elastic member 80312 disposed on an inner surface of the base 500, the outer elastic member 80311 is connected to the third portion 8034, and the inner elastic member 80312 is connected to the first piezoelectric mechanism connection unit 801.

Specifically, referring to fig. 3 and 4, the base 500 is provided with a circuit board escape groove 505, and the inner elastic member 80312 is disposed between the first carrier 100 and the base 500 after passing through the circuit board escape groove 505 and applies elastic force to the second elastic sheet and the second piezoelectric element.

Through such a design, the elastic member 804 can assist the second elastic sheet 404 to provide a certain pressing force to the second piezoelectric element 301, so that the second elastic sheet 404 presses the second piezoelectric element 401 towards the second friction fitting piece 403, and because the second piezoelectric element 401 is fixedly connected with one end of the second friction member 402, the friction force between the second friction member 402 and the second friction fitting piece 403 is increased, thereby improving the driving effect of the second piezoelectric mechanism 400.

In an embodiment of the invention, referring to fig. 3 and 4, the first side wall 520 of the base 500 is provided with a first spring plate mounting groove 502 and a first piezoelectric element mounting groove 501 which are adjacent to each other, and the first spring plate mounting groove 502 and the first piezoelectric element mounting groove 501 which are adjacent to each other extend from the outer side wall of the first side wall 520 to the inner side wall of the first side wall 520 to form a through groove for mounting the first spring plate 304 and the first piezoelectric element 301.

In an embodiment of the invention, referring to fig. 3 and 4, the first elastic sheet 304 is provided with a first conduction avoidance hole 305, and the first piezoelectric element 301 is electrically connected to the first piezoelectric mechanism connecting unit 801 through the first conduction avoidance hole 305.

With such a design, the circuit board 800 is realized to supply power to the first piezoelectric mechanism 300.

In one embodiment of the present invention, referring to fig. 3 and 4, a fourth side wall 120 of the first carrier 100 opposite to the third side wall 540 of the base 500 is provided with a second spring plate mounting groove 103 and a second piezoelectric element mounting groove 102 which are adjacent to each other, and the second spring plate mounting groove 103 and the second piezoelectric element mounting groove 102 which are adjacent to each other extend from an outer side wall of the fourth side wall 120 to an inner side wall of the fourth side wall 120 to form a through groove for mounting the second spring plate 404 and the second piezoelectric element 401.

In an embodiment of the invention, referring to fig. 3 and 4, the second elastic sheet 404 is provided with a second conduction avoiding hole 405, and the second piezoelectric element 401 is electrically connected to the second piezoelectric mechanism connecting unit 802 through the second conduction avoiding hole 405.

With this design, the circuit board 800 is implemented to supply power to the second piezoelectric mechanism 400.

In an embodiment of the present invention, referring to fig. 3 and 4, the lens driving apparatus further includes a position sensor 503 and an induction magnet 504, the second piezoelectric mechanism connecting unit 802 includes a second piezoelectric element connecting portion 8021 and a position sensor mounting portion 804, the second piezoelectric element 401 is electrically connected to the second piezoelectric element connecting portion 8021, and the position sensor 503 is mounted on the position sensor mounting portion 804 and is engaged with the induction magnet 504 mounted at a corresponding position of the second carrier 200.

Specifically, referring to fig. 3 and 4, the position sensor connection unit 804 has a bent structure, and the sensor connection unit 804 having the bent structure is electrically connected to the position sensor 503 disposed on the inner sidewall of the first carrier 100.

With this design, the circuit board 800 is implemented to supply power to the position sensor 503.

In one embodiment of the present invention, the outer surface of the second carrier 200 is provided with an induction magnet mounting groove 202, and an induction magnet 504 is mounted in the induction magnet mounting groove 202.

In one embodiment of the present invention, a fifth sidewall 130 of the first carrier 100 opposite to the first sidewall 520 of the base 500 is provided with a first friction fitting piece installation groove 101, and the first friction fitting piece 303 is installed in the first friction fitting piece installation groove 101; and a sixth side wall 210 of the second carrier 200 opposite to the fourth side wall 120 of the first carrier 100 is provided with a second friction fitting element mounting groove 201, and the second friction fitting element 403 is mounted to the second friction fitting element mounting groove 201.

In an embodiment of the present invention, referring to fig. 1, the lens driving apparatus 1000 further includes a housing 901 and a dust cover 902, the base 500 is disposed in the housing 901, and the dust cover 902 is disposed between the base 901 and the housing 902.

With such a design, the dust cap 902 is disposed at the top end of the base 500, and prevents dust from entering into the gap between the base 500 and the first and

second carriers

100 and 200.

Specifically, referring to fig. 2, 3 and 5, the dust cap 902 includes a top plate 9021 located at the top and a cylindrical portion 9022 formed by extending downward from the top plate 9021, a circular opening 9023 matched with the lens is provided in the middle of the top plate 9021, the circular opening 9023 extends downward and communicates with the inside of the cylindrical portion 9022, an annular protrusion 9024 protruding toward the top plate 9021 is provided inside the cylindrical portion 9022, an annular groove 9025 is formed between the outer surface of the annular protrusion 9024 and the inner surface of the cylindrical portion 9022, and an annular protrusion 9026 protruding inward is provided on the inner surface of the bottom of the cylindrical portion 9022.

In an embodiment of the present invention, referring to fig. 2, 3 and 5, the second carrier 200 includes a lens mounting hole 230 for mounting a lens, a carrier annular boss 240 surrounding the second chamber is disposed on an upper surface of the second carrier 200, and the annular protrusion 9026 of the dust cap 902 is engaged with the carrier annular boss 240 and sleeved outside the carrier annular boss 240.

By such a design, dust can be prevented from effectively entering the gaps between the second carriers 200.

According to another embodiment of the invention, the invention also relates to a piezoelectric element driving frequency

While the preferred embodiments of the present invention have been illustrated and described in detail, it should be understood that various changes and modifications of the invention can be effected therein by those skilled in the art after reading the above teachings of the invention. Such equivalents are intended to fall within the scope of the claims appended hereto.

Claims

1. A method of determining a driving frequency of a lens driving apparatus which is driven by a piezoelectric mechanism, comprising the steps of:

step one, calculating the shearing strain of the piezoelectric element;

secondly, converting the shear strain into the horizontal movement amount of the piezoelectric element;

step three, calculating the total displacement;

and step four, calculating the driving frequency according to the total displacement.

2. The method of determining the driving frequency of a lens driving device according to claim 1, wherein in the first step, the shear strain S of the piezoelectric element is calculated by the following formula:

3. The method of determining a driving frequency of a lens driving device according to claim 2, wherein in the first step, the electric field strength E is calculated by the following equation:

E＝V/L _x wherein V is voltage, L _x Is the piezoelectric thickness.

4. The method of determining the driving frequency of the lens driving device according to claim 1, wherein in the second step, the amount of horizontal movement of the piezoelectric element is calculated using the following formula:

5. The method of determining the driving frequency of a lens driving device according to claim 4, wherein in the third step, the total displacement is calculated by the following equation:

S _{general assembly} =2 × Δ X, wherein S _{General assembly} Δ X is the amount of horizontal movement of the piezoelectric element as the total displacement amount.

6. The method of claim 1, wherein in the step four, the total displacement S is determined according to the following formula _{General assembly} And calculating a driving frequency f, f = V/S for the moving distance V per second _{General assembly} 。

7. The method of determining the driving frequency of a lens driving apparatus according to claim 1, wherein the piezoelectric element of the lens driving mechanism is an n-layer laminated mechanism, and in the third step, the total displacement S _{General assembly} ＝2×ΔX×n。