CN1841105A - Driving mechanism - Google Patents

Abstract

A driving mechanism comprises: (i) an actuator comprising: an electro-mechanical conversion element; a driving member which is connected to one end of the electro-mechanical conversion element and moves according to elongation or contraction of the electro-mechanical conversion element; and a weight member provided on the other end of the electro-mechanical conversion element; (ii) a driven member frictionally engaged with the driving member; and a driving circuit (26) that drives the actuator, wherein the actuator allows the driven member to move along the driving member, and the driving circuit drives the electro-mechanical conversion element at a driving frequency f which gives f 2 1/2 f 0 when resonance frequency of a 1-freedom system is f 0 in which the electro-mechanical conversion element and the driving member are designated as a mass and the weight member is designated as a spring, and driving frequency of the electro-mechanical conversion element is f.

Description

Drive unit

Technical field

The present invention relates to drive unit, relate in particular to a kind of drive unit that is used for driving the more small-sized opticses such as lens of the mobile phone that is configured in small-sized digital camera or web camera or band camera etc.

Background technology

As the drive unit of lens such as digital camera, the known actuator that conversion such as the electric machine that uses piezoelectric element electricity unit is arranged.For example shown in the embodiment of patent documentation 2 and patent documentation 3 like that, actuator is made of electricapparatus conversion element and driver part, and generally the end face of a flexible direction of electricapparatus conversion element is fixed on the basket (perhaps support component).Fixed drive parts on the end face of the flexible other direction of electricapparatus conversion element, this driver part be driven the parts frictional engagement.Such structure, when the electricapparatus conversion element was applied pulse-like voltage, the prolonging direction of electricapparatus conversion element and the action of shrinkage direction were passed on the driver part.Under the situation of electricapparatus conversion element with jogging speed distortion, be driven parts and driver part and together move, under the situation that the electricapparatus conversion element is out of shape with fast speed, be driven parts and stop at the origin-location based on the inertia of its quality.Thereby, be driven parts and move intermittently with trickle interval by applying back and forth different pulse-like voltage, can making.

The actuator of this spline structure, because the end face of a flexible direction of electricapparatus conversion element is fixed on the basket (or support component), so exist following problem, promptly, be directly delivered to basket because of the vibration of electricapparatus conversion element causes comprising the vibration that the actuator of driver part produces, make between actuator and basket, to produce resonance.

Patent documentation 1 has proposed a kind of like this device, promptly, between electricapparatus conversion element and basket, pedestal is set, and by the end face of a flexible direction of electricapparatus conversion element is fixed on the pedestal, and making the relative basket of above-mentioned pedestal form elasticity keeps, reduce or cut off vibration transfer between pedestal and the basket, prevent the influence of being resonated thus.

In addition, the device that patent documentation 2 is proposed, by being made as about one-period of the resonant frequency of electricapparatus conversion element the duration of charging that the electricapparatus conversion element is applied, and being made as for 1/2 cycle discharge time, promptly, increase the stroke of electricapparatus conversion element by utilizing energetically to resonate, thereby improve the driving efficient of actuator.

In addition, the scheme that proposes in patent documentation 3 is, as the driving method of the actuator of the influence of considering resonance, driver part is fixed on the free end of electricapparatus conversion element, and the other end as stiff end, and is being made as f to the resonant frequency of this moment ₁Situation under, make the driving frequency f of actuator be: f ₁/ 3≤f≤2f ₁/ 3

[patent documentation 1] spy opens the 2002-142470 communique

No. 3171187 communique of [patent documentation 2] special permission

No. 3171022 communique of [patent documentation 3] special permission

But, patent documentation 1 described device, owing to be influence fully in order to prevent to be resonated, so, is prerequisite if be with the influence that just can not produce resonance to the pedestal flexible fastening on basket in this device, set the condition of the driving frequency of the resonant frequency of actuator and electricapparatus conversion element, in addition, patent documentation 2 described devices, owing to be to utilize resonance energetically, so, exist the harmful effect that under any circumstance all can be subjected to the resonance of generation in the actuator, thereby make the also problem of the direction displacement beyond the flexible direction of piezoelectric element of driver part.For example, like that, produced the influence that driver part 2 is resonated shown in Figure 17 (A), Figure 17 (B), the problem of the direction displacement beyond the flexible direction of piezoelectric element.Therefore, can not correctly be delivered to based on the flexible driving force of piezoelectric element 1 and to be driven parts 3, be difficult to make be driven parts 3 and on the flexible direction of piezoelectric element 1, correctly move.

In addition, patent documentation 3 described devices, owing to comprise that the resonant frequency of the construction system of basket is higher than driving frequency, so in order to improve resonant frequency, must improve the rigidity of component parts such as piezoelectric element and driver part, perhaps make combination between each parts more firm etc., the construction system that comprises basket is constituted high rigidity.Therefore, exist the high problem of cost of device.In addition, according to the conditional shown in the document, the scope narrow (scope of the Q of Fig. 6 (B)) that can set as driving frequency, therefore, exist following problem, promptly, occurring that device has error qualitatively or when breaking down, resonant frequency descends, and makes to depart from condition, the influence that can be resonated thus.

Summary of the invention

The present invention proposes in view of such situation, its objective is by obtaining the more definite relation of resonant frequency and driving frequency, and the influence that suppresses to resonate, thus a kind of drive unit that carries out correct and stable drive controlling is provided.

To achieve the above object, the present invention's 1 drive unit, it is characterized in that, it has actuator, this actuator, link by the electricapparatus conversion element, with an end of electricapparatus conversion element and corresponding electricapparatus conversion element flexible and driver part that moves and the hammer parts that are arranged on the other end of electricapparatus conversion element constitute, and the parts that are driven with the driver part frictional engagement are moved along driver part; Also has the driving circuit that is used for driving actuator; Driving circuit in 1 system without constraints as spring, is being made as f to electricapparatus conversion element and driver part to resonant frequency as quality and handle hammer parts ₀, when the driving frequency of electricapparatus conversion element is made as f, to become f 〉=2 ^1/2F ₀Driving frequency f, drive the electricapparatus conversion element.

1 drive unit according to the present invention owing to drive the electricapparatus conversion element to set driving frequency f as described above, so the influence of resonance is very little, can be on the flexible direction of electricapparatus conversion element correctly drive controlling be driven parts.

In addition, 1 drive unit according to the present invention can be set driving frequency in wide region.Thereby, even under the situation that causes resonant frequency to change because of the carrying capacity of environment of temperature variation etc. or tolerance of goods etc., the setting that does not also need to change driving frequency.

The present invention's 2 is in the present invention's 1 drive unit, it is characterized in that, makes the resonant frequency f of actuator ₀For: f ₀≤ 70kHz.

The present invention's 3 is in the present invention's 1 or 2 drive unit, it is characterized in that, the modulus of longitudinal elasticity of the material of hammer parts is lower than the modulus of longitudinal elasticity of the material of electricapparatus conversion element.

The present invention's 4 be the present invention 1～3 in any one drive unit, it is characterized in that the modulus of longitudinal elasticity of the material of hammer parts is below the 1Gpa.

By setting the modulus of longitudinal elasticity of hammer parts as described above, can reduce resonant frequency, and can prevent from driving frequency range, to produce resonance.The modulus of longitudinal elasticity of preferred hammer parts is more wished below 300MPa below 1GPa.

The present invention's 5 be the present invention 1～4 in any one drive unit, it is characterized in that the hammer parts reduce parts by the resonant frequency of the resonant frequency that reduces actuator and constitute.

The present invention's 6 is in the present invention's 5 drive unit, it is characterized in that, reduces the hammer parts that parts constitute by being provided with by resonant frequency, than the situation that the hammer parts that are made of rigid material are set, can reduce the resonant frequency of actuator.

The present invention's 7 be the present invention 1～6 in any one drive unit, it is characterized in that driver part is supported for, its front and/or its base end side can move on the flexible direction of electricapparatus conversion element.

The present invention's 8 be the present invention 1～7 in any one drive unit, it is characterized in that the side from the flexible direction of relative electricapparatus conversion element is supported on actuator on the basket.

The present invention's 9 be the present invention 1～8 in any one drive unit, it is characterized in that having driver element, its generation be used for driving the electricapparatus conversion element, at elongation and the asymmetrical signal of shrinkage direction.

The present invention's 10 be the present invention 1～9 in any one drive unit, it is characterized in that, be driven parts and contact with driver part formation face.

The present invention's 11 be the present invention 1～10 in any one drive unit, it is characterized in that having the detecting unit that detects the shift position that is driven parts.

The present invention's 12 be the present invention 1～11 in any one drive unit, it is characterized in that, drive the electricapparatus conversion element with the driving frequency that surpasses audible frequency.In this case, can reduce the action sound in zone of audibility of electricapparatus conversion element.

The present invention's 13 be the present invention 1～12 in any one drive unit, it is characterized in that, be driven parts and optics and link, be used in the photographic optical system.In this case, optics is not limited only to lens, is driven parts and also can uses in aperture, shutter or ND color filter etc.

The present invention's 14 be the present invention 1～13 in any one drive unit, it is characterized in that actuator is used in the photographic optical system set in the mobile phone.In this case, this actuator is not limited only to use in the photographic optical system in being set at mobile phone, also can use in the photographic optical system of smaller types such as network camera or small-sized digital camera.

(invention effect)

According to drive unit of the present invention, because to become f 〉=2 ^1/2F ₀Driving frequency f drive the electricapparatus conversion element, so the influence of being resonated is very little, can be correctly and stably on the flexible direction of electricapparatus conversion element drive controlling be driven parts, and can in wide region, set driving frequency f.

Description of drawings

Fig. 1 is the vertical view of actuator of the drive unit of expression the present invention the 1st embodiment.

Fig. 2 is the oscillogram that is applied to the driving pulse on the piezoelectric element.

Fig. 3 is the mode chart of Support Position of the actuator of presentation graphs 1.

Fig. 4 is the vertical view of the drive unit of expression the present invention the 1st embodiment.

Fig. 5 is the sectional view of expression along the V-V line of Fig. 4.

Fig. 6 is the figure of explanation at the driving frequency range of resonant frequency.

Fig. 7 is the stereographic map of the drive unit of expression the present invention the 2nd embodiment.

Fig. 8 is the vertical view of the drive unit of presentation graphs 7.

Fig. 9 is the vertical view of the drive unit of expression the present invention the 3rd embodiment.

Figure 10 is the vertical view of the drive unit of expression the present invention the 4th embodiment.

Figure 11 is the vertical view of the drive unit of expression the present invention the 5th embodiment.

Figure 12 is the sectional view along the XII-XII line of Figure 11.

Figure 13 is the circuit diagram of driving circuit of the drive unit of expression Figure 11.

Figure 14 is the oscillogram of input signal that is input to the driving circuit of Figure 13.

Figure 15 is the oscillogram from the output signal of the driving circuit output of Figure 13.

Figure 16 is the figure of the calculated example of expression resonant frequency.

Figure 17 is the key diagram that the bad phenomenon of actuator in the past is described.

Among the figure: 1-piezoelectric element (electricapparatus conversion element); 2,14-driver part; 3,16,216,516-is driven parts; 10,210,310,410,510-actuator; 18,218,332,418,518-hammers parts into shape; 20,24,610-main body (basket) 26,215-driving pulse feedway (driving circuit) 68,221-lens frame; 77-driving circuit 100,200,300,400,500-drive unit; The f-driving frequency; f ₀-resonant frequency.

Embodiment

Below, with reference to accompanying drawing, the preferred implementation of drive unit of the present invention is elaborated.In addition, in the description of the drawings, the symbol identical to identical key element mark, and omit repeat specification.

Fig. 1 is the vertical view of actuator 10 of the drive unit 100 of expression the present invention the 1st embodiment.As shown in Figure 1, actuator 10 is made of piezoelectric element (being equivalent to the electricapparatus conversion element) 12, driver part 14 and hammer parts 18.Piezoelectric element 12 constitutes in the direction of arrow stacked, by applying voltage, to the structure of stacked direction distortion (stretching).Thereby, make end face 12A, the 12B of the length direction of piezoelectric element 12 carry out displacement.

On the end face 12A of the side in end face 12A, the 12B of piezoelectric element 12, be fixedly connected with the cardinal extremity of driver part 14.Driver part 14 for example forms cylindric, and its axle is configured on the direction of arrow (that is the flexible direction of piezoelectric element).The material of driver part 14, the suitable material that adopts light and high rigidity, the material as satisfying this condition it is desirable to beryllium, but because this material is a rare metal, costs an arm and a leg and the shortcoming of poor in processability so exist.Therefore, adopted the graphite composite that makes graphite crystal powerful compound in the present embodiment, for example carbon graphite.(here, graphite composite is meant the graphite of hexagonal plate crystal body of carbon and the complex of the material beyond the graphite, and carbon graphite is meant the material that is made of graphite and agraphitic carbon.And graphite is called blacklead again.) as the carbon graphite of this graphite composite, (proportion of beryllium is about 1.85 owing to not only have the characteristic similar to beryllium, the proportion of carbon graphite is about 1.8), but also have the characteristic of the low and easy processing of the price comparison that is different from beryllium, so can reduce the cost of actuator 10.In addition, the shape of driver part 14 is not limited to cylindric, also can be prism-shaped.

Be driven parts 16, combine with driver part 14, supported sliding freely along driver part 14 with the friction force of stipulating.The friction force that is driven parts 16 and driver part 14 is set to: when piezoelectric element 12 has applied the voltage of slow variation, make stiction greater than its driving force, and when piezoelectric element 12 has been applied voltage jumpy, make stiction less than its driving force.In addition, in order to make action stable, and improve the permanance when driving repeatedly, partly smeared lubricant in driver part 14 and the sliding contact that is driven parts 16.The lubricant that the preferred usability of this lubricant is not easy to be acted upon by temperature changes is not even so that increase driver part 14 and the slip driving impedance that is driven parts 16 at low temperatures yet.In addition, preferred employing does not produce the structure of dust, in order to avoid optics and mechanism components are caused harmful effect.

Hammer parts 18 are fixed on the end face 12B of piezoelectric element 12.This hammers parts 18 into shape, applies load by the end face 12B to piezoelectric element 12, prevents the displacement of the displacement of end face 12B greater than end face 12A, and preferably it is than the Heavy Weight of driver part 14.And, by the hammer parts 18 bigger than the quality of driver part 14 are set, can be flexible driver part 14 sides that are delivered to expeditiously of piezoelectric element 12.For example, be that 8mg, piezoelectric element 12 are under the situation of 30mg at driver part 14, use the hammer parts 18 of 20mg.

In addition, hammer parts 18 are formed by flexible material.As the material of hammer parts 18, use its modulus of longitudinal elasticity material littler than piezoelectric element 12 and driver part 14.As the modulus of longitudinal elasticity of hammer parts 18, below the preferred 1GPa, preferably smaller or equal to 300MPa.Such hammer parts 18 are to form by the metal powder that mixing ratio is great in elastic bodys such as rubber, for example, make by the powder that mixes tungsten in urethane rubber or urethane resin.About the proportion of hammer parts 18, for the miniaturization of implement device, should be provided with highly as far as possible, for example be set at 8～12 degree.In addition, the modulus of longitudinal elasticity of the hammer parts of making by the powder that has mixed tungsten in urethane rubber or urethane resin 18 is about 60Mpa, proportion is about 11.7.Therefore, under the situation that designs hammer parts 18 with as far as possible little volume, though it would be desirable the combination of big as far as possible proportion and as far as possible little modulus of longitudinal elasticity, but as long as hammer parts 18 are more great (promptly than the ratio of driver part 14, proportion is more than or equal to 1.8) and modulus of longitudinal elasticity smaller or equal to 1GPa, promptly can use.That is, if proportion divided by the numerical value (proportion/modulus of longitudinal elasticity) of modulus of longitudinal elasticity more than or equal to 1.8 * 10 ^-9, promptly be suitable as hammer parts 18.

Piezoelectric element 12 is electrically connected with driving pulse feedway (driving circuit) 26 (with reference to Fig. 4), is applied the voltage of the waveform shown in Fig. 2 (A), Fig. 2 (B) by this driving pulse feedway 26.For the output signal of this Fig. 2 (A), Fig. 2 (B), that is, make the electric signal of piezoelectric element 12 actions, use the signal of super audible frequency.By using the signal of this frequency, can reduce the action sound of piezoelectric element 12 in zone of audibility.In addition, in embodiment described later, use the signal of this super audible frequency too.

Fig. 2 (A), Fig. 2 (B) show the figure of an example of the pulse waveform that applies to piezoelectric element 12.Fig. 2 (A) be make Fig. 1 be driven left the pulse waveform when mobile of parts 16 to arrow, Fig. 2 (B) makes that Fig. 1's be driven the pulse waveform of parts 16 when the right of arrow moves.

Under the situation of Fig. 2 (A), piezoelectric element 12 applied from moment α 1 to moment α 2 slowly rise, the roughly jagged driving pulses that sharply descend at moment α 3.Therefore, from moment α

1 to moment α 2, and piezoelectric element 12 slowly extends.At this moment, because driver part 14 moves with speed slowly, together move with driver part 14 so be driven parts 16.Like this, can make and be driven the left of parts 16 in Fig. 1 to moving.At moment α 3, owing to driver part 12 sharply shrinks, so the right of driver part 14 in Fig. 1 moves.At this moment, because driver part 14 sharply moves, to stop at original position based on inertia effect motionless so be driven parts 16, and have only driver part 14 to move.Therefore,, make the action of moving and stopping that parts 16 carry out direction left repeatedly that is driven of Fig. 1 by applying the jagged driving pulse shown in Fig. 2 (A) repeatedly, thus can make its left direction move.

Under the situation of Fig. 2 (B), piezoelectric element 12 is applied to moment β 1 sharply rises, at the 3 roughly jagged driving pulses that slowly descend from moment β 2 to moment β.Therefore, sharply extend at moment β 1 piezoelectric element 12, the left of driver part 14 in figure is to moving.At this moment, because driver part 14 sharply moves, to stop at original position under inertia effect motionless so be driven parts 16, and have only driver part 14 to move.From moment β 2 to moment β 3, piezoelectric element 12 slowly shrinks.At this moment, because driver part 14 slow displacements are together moved with driver part 14 so be driven parts 16.Like this, can make and be driven the right of parts 16 in Fig. 1 and move.Therefore, by applying the zigzag driving pulse shown in Fig. 2 (B) repeatedly, the parts 16 that are driven of Fig. 1 are carried out repeatedly to the moving and stop action of right, so it is moved to right.In addition, the zigzag driving pulse is the signal that schematically uses in order to describe, and in practice, is by the such circuit input and output Figure 14 of Figure 13, signal shown in Figure 15.This output signal and the equivalence of zigzag driving pulse.In addition, as employed driving frequency,, and reduce the aspect of power consumption if consider and make driving frequency avoid being used as a kind of abnormal sound and the audible frequency section that can be heard, preferably select to use 20kHz～200kHz, the better 50kHz～100kHz that is to use.

Here, being delivered on the basis or pedestal of supporting them from the machinery or the structure of vibration in order not make vibration, generally is to wish that conduct vibrations rate λ (Vibration Transmissibility) is the smaller the better.In equivalent 1 system without constraints, conduct vibrations rate rate λ is by 1 expression of following formula.

[formula 1]

$\mathrm{\λ}=\sqrt{\frac{1+{\left(2\mathrm{\ζ}\frac{f}{f_0}\right)}^2}{{(1+{\left(\frac{f}{f_0}\right)}^2)}^2+{\left(2\mathrm{\ζ}\frac{f}{f_0}\right)}^2}}$

Wherein,

λ: the conduct vibrations rate of equivalent 1 system without constraints,

F: employed driving frequency,

f ₀The resonant frequency of equivalence 1 system without constraints,

ξ: the attenuation ratio of equivalent 1 system without constraints.

And, in equivalent 1 system without constraints, this conduct vibrations rate λ smaller or equal to 1 situation under, irrelevant with the ξ value, the vibration of machinery is not easy to be delivered on basis or the pedestal.Therefore, as following formula 2 and with shown in the formula 3 after formula 2 distortion, conduct vibrations rate λ promptly, satisfies f 〉=2 smaller or equal to 1 scope ^1/2F ₀Scope (the scope P of Fig. 6 (A)), be the support component very little vibrationproof zone of influence (for example main body 20 of Fig. 4), that resonated that the vibration of piezoelectric element 12 is not easy to be delivered to actuator 10.In addition, about the vibrationproof zone, for example be documented in [pattern is resolved and crossed the threshold, the clear man's work of long pine, コ ロ Na publishing house].In addition, f 〉=2 ^1/2F ₀Relation, for other embodiment, also be suitable for certainly.

[formula 2]

$1\≥\mathrm{\λ}=\sqrt{\frac{1+{\left(2\mathrm{\ζ}\frac{f}{f_0}\right)}^2}{{(1+{\left(\frac{f}{f_0}\right)}^2)}^2+{\left(2\mathrm{\ζ}\frac{f}{f_0}\right)}^2}}$

[formula 3]

f≥2 ^1/2·f ₀

Therefore, driving pulse feedway 26 applies above-mentioned pulse-like voltage with specific driving frequency f to piezoelectric element 12.That is, piezoelectric element 12 and driver part 14 as quality, will be made as f to hammer parts 18 as the resonant frequency of equivalence 1 system without constraints of spring ₀, when the driving frequency of piezoelectric element 12 is made as f, to satisfy f 〉=2 ^1/2F ₀Driving frequency f drive pressure electric device 12.In addition, can obtain resonant frequency f by following formula ₀In the formula, E represents to hammer into shape the modulus of longitudinal elasticity of parts 18, and A represents to hammer into shape the area of parts 18 in piezoelectric element 12 sides, and h represents to hammer into shape the thickness of parts 18, and Ma represents the quality of piezoelectric element 12, and Mb represents the quality of driver part 14, and Mc represents to hammer into shape the quality of parts 18.

[formula 4]

${\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="A20061007174900301.png"\; state="\{\{state\}\}">f</figure-callout>}}_0=\frac{1}{2\mathrm{\&pi;}}\sqrt{\frac{\mathrm{EA}}{(\mathrm{Ma}+\mathrm{Mb}+\frac{1}{3}\mathrm{Mc})h}}$

Below, the effect of the actuator 10 of above-mentioned formation is described.

In the present embodiment, with respect to resonant frequency f ₀And satisfy f 〉=2 in vibrationproof zone ^1/2F ₀Driving frequency f, piezoelectric element 12 is carried out drive controlling.Therefore, according to present embodiment, can prevent that driver part 14 from vibrating to the flexible direction direction in addition of piezoelectric element 12 based on resonance.Thus, because driver part 14 displacement on the flexible direction of piezoelectric element 12, be driven parts 16 so can be correctly be passed to flexible driving force based on piezoelectric element 12, thus can be on the flexible direction of piezoelectric element 12 correctly drive controlling be driven parts 16.

In addition, according to present embodiment, f 〉=2 can become ^1/2F ₀Wide region in set the driving frequency f of actuator 10.Thus, even make above-mentioned resonant frequency f because of the carrying capacity of environment of temperature variation etc. or tolerance of goods etc. ₀Under the situation that has taken place to change, do not need to change the setting of driving frequency f yet, thereby do not need change that each actuator 10 set.

In addition, in the present embodiment, the hammer parts 18 that are fixed on the end face 12B of piezoelectric element 12 are formed by the little flexible material of modulus of longitudinal elasticity.By using such hammer parts 18, can significantly reduce piezoelectric element 12 and driver part 14 as quality, the resonant frequency f of hammer parts 18 as elastomeric equivalent system without constraints ₀, in other words, hammer parts 18 can play the effect that reduces parts as the resonant frequency that reduces resonant frequency.In addition,, compare, can reduce the resonant frequency of actuator 10 with the situation that the hammer parts that are made of rigid material are set by the hammer parts 18 that use the little flexible material of modulus of longitudinal elasticity to form.This point can draw from above-mentioned formula 1 clearly.That is, in formula 1, if reduce to hammer into shape the modulus of longitudinal elasticity of parts 18, resonant frequency f then ₀Step-down.In the present embodiment, by making the modulus of longitudinal elasticity of hammering parts 18 into shape smaller or equal to 1GPa, can be resonant frequency f ₀Be reduced to smaller or equal to 70kHz.In addition, in the present embodiment, if make the modulus of longitudinal elasticity of hammering parts 18 into shape smaller or equal to 300MPa, then can be resonant frequency f ₀Be reduced to smaller or equal to 35kHz.And, in the present embodiment, under the situation of the hammer parts 18 that mixed tungsten powder in the urethane rubber that has used about modulus of longitudinal elasticity is as 60Mpa, resonant frequency f ₀For about 15kHz (with reference to symbol among Figure 16 1.Wherein, E+07 represent * 10 ⁷).

And if adopt the big hard material of modulus of longitudinal elasticity to form the parts that are equivalent to hammer into shape, then resonant frequency f ₀Increase.For example, in the present embodiment, be under the situation of stainless steel of 200～400GPa as the material of hammer parts 18 adopting modulus of longitudinal elasticity, resonant frequency f ₀To reach more than or equal to 1GPa.And, even adopted under the situation of the less relatively aluminium of the modulus of longitudinal elasticity in the metal (modulus of longitudinal elasticity is about 120GPa) above-mentioned resonant frequency f ₀Also be about 700kHz (with reference to the symbol among Figure 16 5).

As mentioned above, the actuator 10 of present embodiment forms hammer parts 18 owing to adopt resonant frequency to reduce parts, so can be the resonant frequency f of equivalent 1 system without constraints ₀Be reduced to smaller or equal to 70kHz.Therefore, the driving frequency f of normally used 50kHz～100kHz can satisfy f 〉=2 ^1/2F ₀Do not need to set high driving frequency f and just can satisfy f 〉=2 ^1/2F ₀Thereby, can reduce power consumption.In addition, even, also can reach same effect adopting elastic body or viscoelastic material to constitute under the situation of hammer parts 18.

And, according to present embodiment, because by reducing the resonant frequency f of the actuator that constitutes by piezoelectric element 12, driver part 14 and hammer parts 18 10 itself ₀Can eliminate the harmful effect that is caused because of resonance, so, except can reducing influence as the tolerance of component parts because of actuator, also owing to no matter be installed in actuator on the basket in which way, all be not easy the influence of being resonated, so can increase design when actuator is installed and the degree of freedom of manufacturing.That is, also can utilize support component 23 to support the end face 12A of piezoelectric element 12 shown in Fig. 3 (A) like that, also can utilize support component 23 to support the side of piezoelectric element 12 shown in Fig. 3 (B) like that.And, the side or the rear end face of front end face that also can support drive parts 14 or side, front and/or base end side or hammer parts 18.

Fig. 4 is the vertical view of the drive unit 100 of expression the present invention the 1st embodiment.This drive unit 100 is that actuator 10 is configured in device on the mobile phone etc. of band camera, and actuator 10 is used to make moving lens (not shown) such as zoom lens to move.

Actuator 10 shown in Figure 4 is identical with the situation shown in Fig. 3 (A), and is supported by the end face 12A of piezoelectric element 12.That is, the end face 12A of piezoelectric element 12 is adhesively fixed on the support portion 20A that is formed on the main body (basket) 20.

On main body 20, form porose 20B.Hole 20B forms has the diameter bigger slightly than the external diameter of driver part 14, constitutes holding state by the front end of driver part 14 is inserted in the 20B of this hole.

As shown in Figure 5, be driven the groove 16A that parts 16 have the V font, driver part 14 is fastened in this groove 16A.In addition, be driven parts 16 and have leaf spring 22, utilize this leaf spring 22 that driver part 14 is pressed in and be driven parts 16 sides.Like this, be driven parts 16 and contact with driver part 14 formation lines, become substantial contact at 3 positions.Like this, constitute the structure of the frictional engagement that is driven parts 16 and driver part 14.Be driven parts 16 below, be connected with the maintenance frame (not shown) that keeps moving lens.

Under situation as constituted above, by to satisfy f 〉=2 ^1/2F ₀Driving frequency f come drive pressure electric device 12, can on its flexible direction, correctly be delivered to the driving force of piezoelectric element 12 and be driven on the parts 16.

Below, in conjunction with Fig. 7 and Fig. 8, the drive unit 200 of the 2nd embodiment of the present invention is described.Here, omit the explanation identical, only difference is described with the 1st embodiment.

As shown in Figure 7 and Figure 8, on this drive unit 200, dispose actuator 210.The lens frame 221 that is driven parts 216 and moving lens 211 forms as one.Lens frame 221 is guided by the guide pole (not shown) with driver part 14 configured in parallel, to prevent its circumference rotation along driver part 14.In addition, be driven on the parts 216, be formed with the groove 216B of U font, driver part 14 is fastened in this groove 216B.On each position in four bights that are driven parts 216, be provided with upward outstanding teat 224,224 ..., by these teats 224,224 ... be provided with friction plate 226 in institute's area surrounded.Friction plate 226 forms match with the side view of driver part 14 circular-arc by crooked.Thereby form the face state of contact that is driven parts 216 and driver part 14.In addition, to each bight of friction plate 226, with cooperation be driven parts 216 teat 224,224 ... shape carried out local excision.Therefore, friction plate 226 is configured in by teat 224,224 ... in the time of in institute's area surrounded, can prevent coming off of friction plate 226.

Be equipped with by pressing spring 228 being driven on the parts 216.Constitute a friction plate 226 by pressing spring 228 and be driven parts 216 sides by being pressed in.Thereby, in driver part 14 being configured in the U font groove 216B that is driven parts 216 and after disposing friction plate 226 in the above, friction plate 226 spring 228 that is pressed is pressed on the driver part 14, utilize friction plate 226 and be driven parts 216 clamping driver parts 14, thereby can will be driven parts 216 and driver part 14 frictional engagement.

On the end face 12B of piezoelectric element 12 rear ends, be adhesively fixed with soft hammer parts 218.In order to realize miniaturization, wish that the proportion of hammer parts 218 is high as far as possible, for example, be set at the degree identical (7.7～8.0) with stainless steel.Hammer parts 218 are bonded with installing component 230 on the opposition side of the face that piezoelectric element 12 has been installed, by this installing component 230 hammer parts 218 are supported on the main body 20.Installing component 230 is formed コ shape by crooked metal sheet, and the sweep at its two ends is fixed on the main body 20 by chimeric.Piezoelectric element 12 is electrically connected with driving pulse feedway 215 (with reference to Fig. 8), applies voltage by this driving pulse feedway 215 to piezoelectric element 12.In addition, in the present embodiment, though hammer parts 218 are to utilize installing component 230 to be fixed on the main body 20, a hammer parts 218 is directly installed on the main body 20 and also can reaches same effect.

Like this, in the present embodiment,, the rear end end face 12B of piezoelectric element 12 is supported near free-ended state by the hammer parts 218 that constitute by soft elastic body, but the resonant frequency f of handle assembly construction system thus ₀Be reduced to 20kHz～30kHz.And driving pulse feedway 215 is with relative this resonant frequency f ₀And satisfy f 〉=2 ^1/2F ₀Driving frequency f drive pressure electric device 12.Satisfy f 〉=2 ^1/2F ₀Scope, be that the conductivity of power becomes the vibrationproof zone smaller or equal to 1, do not produce resonance.Therefore,, the resonance of locking apparatus construction system can be prevented, stable drive amount can be guaranteed all the time according to present embodiment.

Below, with reference to Fig. 9, the drive unit 300 of the present invention's the 3rd embodiment is described.

As shown in Figure 9, the difference of this drive unit 300 and drive unit 200, be to be adhesively fixed with the hammer parts 332 that are made of elastic bodys such as rubber on the end face 12B of the rear end side of piezoelectric element 12, the face of the opposition side of the relative piezoelectric element 12 of these hammer parts 332 is adhesively fixed on the main body 20.Like this, also can reach with above-mentioned embodiment same, guarantee the action effect of stable drive amount all the time.

Below, with reference to Figure 10, the drive unit 400 of the present invention's the 4th embodiment is described.

As shown in figure 10, the difference of this drive unit 400 and drive unit 200, be to form by the hammer parts 418 that flexible material constitutes to have the lamellar of the face bigger than the end face 12B of piezoelectric element 12, at the middle position of these hammer parts 418 piezoelectric element 12 that is adhesively fixed, the both ends of hammer parts 418 are adhesively fixed on the main body 20.Owing to utilize lamellar hammer parts 418 to be supported on the main body 20 in this wise,, make the end face 12B displacement of the rear end of piezoelectric element 12 to the end face 12B of the rear end of piezoelectric element 12 by hammering the buckling deformation of parts 418 into shape.And because the modulus of longitudinal elasticity of hammer parts 418 is little, so the end face 12B of the rear end of piezoelectric element 12 is supported near free-ended state by hammer parts 418.Thereby can reduce resonant frequency f ₀, can be in the f that becomes the vibrationproof zone 〉=2 ^1/2F ₀Wide region in use driving frequency f.Therefore, can prevent the resonance of locking apparatus construction system, guarantee stable drive amount all the time.

In addition, also can support the end face 12B of the rear end of piezoelectric element 12, can improve the inhibition effect of resonance like this by viscoelastic body.That is, elastic bodys such as resin, rubber have viscosity mostly, and this viscosity has the absorption vibrational energy, this energy conversion is become character hot and that dispel the heat.Therefore, can prevent the resonance of locking apparatus construction system and the harmful effect that vibration caused of the direction beyond the purpose direction.

Below, the drive unit 500 of the present invention's the 5th embodiment is described.

Figure 11 is the sectional view of the drive unit 500 of the present invention's the 5th embodiment.As shown in figure 11, the drive unit 500 of present embodiment, moving lens 70 is carried out the driving of moving lens 70 as mobile object, and it comprises: have piezoelectric element 12 and driver part 14 actuator 510, support the support component 60 of this actuator 510 and be driven parts 516.Piezoelectric element 12 is the electricapparatus conversion elements that can stretch by input electrical signal, and it can elongation and contraction on the direction of regulation.This piezoelectric element 12 is connected with control part 71, by stretching from these control part 71 input electrical signals.For example, on piezoelectric element 12, be provided with 2 input terminal 72A, 72B.Be applied to voltage on this input terminal 72A, the 72B by increase and decrease repeatedly, piezoelectric element 12 is extended repeatedly and shrink.

Driver part 14 is installed on the piezoelectric element 12 towards length direction on the flexible direction of piezoelectric element 12.For example, an end of driver part 14 and piezoelectric element 12 butts, use bonding agent 27 to carry out bonding.This driver part 14 is parts of elongate, for example, uses columned parts.About the material of driver part 14, use the powerful compound graphite crystallization complex of graphite crystallization, for example use carbon graphite.Driver part 14 is supported for mobile status alongst by the separating part 24B that extends to the inside from main body 24, separating part 24C.Separating part 24B, separating part 24C are the parts that are used to separate the moving area that is driven parts 516, and have the function as the support component of driver part 14.

On separating part 24B, separating part 24C, be formed with respectively and make driver part 14 insert logical through hole 24A.Near the position of the mounting portion of the piezoelectric element 12 of separating part 24B support drive parts 14, that is, and the cardinal extremity position of driver part 14.The front end position of separating part 24C support drive parts 14.Main body 24 is brought into play function as the framework that is used for assembly actuator 510 or frame parts.By driver part 14 is installed on the piezoelectric element 12, makes the perseveration of the elongation of its corresponding piezoelectric element 12 and contraction and move back and forth along its length direction.

In addition, in Figure 11, represented by separating part 24B, 24C in the front of driver part 14 and two situations that support drive parts 14 are come at the position of base end side, but the situation of coming support drive parts 14 a side of its front or base end side has also been arranged.For example, by the through hole 24A of separating part 24B being formed external diameter greater than driver part 14, form into by separating part 24C only in the structure of front end position support drive parts 14.In addition, by the through hole 24A of separating part 24C being formed external diameter greater than driver part 14, form into by separating part 24B only in the structure of cardinal extremity position support drive parts 14.In addition, in Figure 11, represented separating part 24B, the 24C of support drive parts 14 and the situation that main body 24 forms as one, be installed in structure on the main body 24 but also can be designed to separating part 24B, 24C with main body 24 splits.Even under the situation of split, also can reach the effect identical with the situation of one.

Being driven parts 516 is movably mounted on driver part 14.This is driven parts 516 and is installed into and driver part 14 frictional engagement and can moving along its length direction.For example, be driven the friction factor that parts 516 are installed into regulation and combine with driver part 14, by pushing driver part 14 with certain pressing force, the structure of the certain friction force of generation when it moves.Be driven parts 516 opposing friction force and move by applying displacing force to being driven parts 516, making along driver part 14 above friction force.

Actuator 510 is supported on the main body 24 by support component 60.Support component 60 supports actuator 510 from the direction with the flexible direction quadrature of piezoelectric element 12, and this support component 60 is configured between the main body 24 and piezoelectric element 12 of taking in actuator 510.

Support component 60 is formed by the elastic body with the above elastic property of regulation, for example, is formed by silicone resin.Support component 60 is constituted as and is formed with the inserting hole 60A that inserts logical piezoelectric element 12, and in that piezoelectric element 12 is inserted under the state that leads in this inserting hole 60A, is assembled on the main body 24.In addition, by using the bonding of bonding agent 61, support component 60 is adhesively fixed on the main body 24.In addition, between support component 60 and the piezoelectric element 12, also use bonding agent to be adhesively fixed.By constitute this support component 60 by elastic body, can be supported for the structure that can on the flexible direction of piezoelectric element 12, move to actuator 510.In Figure 11, support component 60 is expressed as being positioned at 2 of piezoelectric element 12 both sides, but is actually a continuous support component 60, and this support component the 60, the 60th is depicted as 2 result when representing support component 60 with sectional view.

In addition, also can be by between main body 24 and piezoelectric element 12, being pressed into support component 60, and push support component 60, carry out the fixed installation of support component 60 and main body 24 fixed installations and piezoelectric element 12.For example, utilize elastic body to constitute support component 60, and form, it is pressed into is arranged on therebetween than the big shape in interval between main body 24 and the piezoelectric element 12.Thereby, support component 60 is configured to the state of combining closely with main body 24 and piezoelectric element 12.In this case, piezoelectric element 12 by support component 60 from pushing with the both sides of the direction of flexible direction quadrature.Support actuator 510 thus.

In addition, illustrated here and used silicone resin to form the situation of support component 60, but also can utilize spring members to constitute support component 60.For example, also can between main body 24 and piezoelectric element 12, dispose spring members, actuator 510 is supported on the main body 24 by this spring members.

Be driven on the parts 516, scioptics frame 68 is equipped with moving lens 70.Moving lens 70 is used to constitute the photographic optical system of camera, is the mobile object of drive unit.This moving lens 70 is configured to and is driven parts 516 and is combined into one, and be driven the structure that parts 516 together move.On the optical axis O of moving lens 70, dispose not shown fixed lens etc., and constituted the photographic optical system of camera.In addition, on optical axis O, dispose imaging apparatus 65.Imaging apparatus 65 is the imaging apparatuss that the image transitions by the photographic optical system imaging become electric signal, for example is made of CCD.Imaging apparatus 65 is connected with control part 71, and picture signal is outputed to control part 71.

Hammer parts 518 are installed in the end of piezoelectric element 12.Hammer parts 518 are the parts that are used for the contractility of piezoelectric element 12 is delivered to driver part 14 sides, and it is installed on the end of piezoelectric element 12 and the opposition side end that driver part 14 is installed.As hammer parts 518, use the parts that weigh than driver part 14.In addition, as hammer parts 518, preferably use the parts of in the parts of elastically deformable, having sneaked into metal powder.Can gain in weight by the pick-up metal powder, by using the parts of elastically deformable, the unwanted resonance of piezoelectric element 12 when action can decay.In addition, constitute hammer parts 518 by adopting flexible member, the driving frequency of piezoelectric element 12 relatively can fully reduce the resonant frequency of actuator 510, thus the influence that can reduce to resonate.

In addition, hammer parts 518 are configured to not be supported and fixed on the state on the main body 24.That is, hammer parts 518 are configured to directly not supported or be fixed on the main body 24 and are not supported or be fixed into limited its state that moves on main body 24 by bonding agent or resin material.

Be provided with the detecting device 75 that is used to detect the shift position that is driven parts 516 in the drive unit 500.As detecting device 75, for example, can use optical detector, can use reflective optical system, Photo Interrupter etc.Specifically be, as detecting device 75, have in use under the situation of reverberator 75A and test section 75B, on the lens frame 68 integrally formed, reverberator 75A is installed with being driven parts 516, penetrate detection light from test section 75B to reverberator 75A side, in reverberator 75A side, by detecting the reflected light that is reflected by test section 75B, detect the shift position that is driven parts 516 and moving lens 70.

Detecting device 75 is connected with control part 71.The output signal of detecting device 75 is input to control part 71.The integral body of control part 71 accessory drives for example is made of CPU, ROM, RAM, input signal circuit, output signal circuit etc.In addition, control part 71 has the driving circuit that is used to make piezoelectric element 12 actions, the electric signal that it is used to drive to piezoelectric element 12 outputs.

Figure 12 is the sectional view that is driven parts 516 of the XII-XII line of Figure 11.As shown in figure 12, be driven parts 516, for example comprise main part 516A, press section 516B and sliding part 516C.Utilize press section 516B, with driver part 14 with certain power by being pressed on the main part 516A.On main part 516A, be formed with the groove 516D of V font.In this groove 516D, take in the driver part 14 that is by the state of 2 sliding part 516C, 516C clamping.Sliding part 516C, 516C are that section is the plate body of V font, and are configured to make the recess side opposed mutually, and the state that driver part 14 is clipped in the middle.By in this wise driver part 14 being accommodated in the groove 516D of V font, can stably be installed on the driver part 14 being driven parts 516.

As press section 516B, for example, use the plate spring component of section as the L font.By one side of press section 516B is hooked on the main part 516A, another side is configured on the opposed locations of groove 516D, can be by another side the driver part 14 and main part 516A and together clamping of sliding part 516C that are accommodated among the groove 516D.Like this, can press to driver part 14 sides to main part 516A.

Like this, by main part 516A being installed and is driven parts 516 by pressing to driver part 14 sides with certain power, can make itself and driver part 14 constitute frictional engagement by press section 516B.That is, be driven parts 516 and be installed into and make main part 516A and press section 516B push driver part 14, and when it moves, produce the state of certain friction force with certain pressing force.

In addition, by being sliding part 516C, the 516C clamping driver part 14 of V font by section, make to be driven parts 516 and to contact with driver part 14 lines, promptly at 4 positions, become substantial contact, can form stable frictional engagement thus with driver part 14.

Figure 13 is the circuit diagram that makes the driving circuit of piezoelectric element 12 actions.As shown in figure 13, driving circuit 77 is configured in the control part 71.This driving circuit 77 has the function as the driving circuit of piezoelectric element 12, and it drives to piezoelectric element 12 outputs and uses electric signal.Driving circuit 77 carries out voltage amplification or electric current amplification from control signal generating unit (not shown) input control signal of control part 71 to this control signal, exports the driving electric signal of piezoelectric element 12 then.Driving circuit 77 uses for example to constitute input stage by logical circuit U1～U3, has the circuit of field effect transistor (FET) Q1, Q2 in output stage.Transistor Q1, Q2 constitute exportable H output (noble potential output) as output signal, L output (electronegative potential output) and OFF output (empty output).

Figure 14 represents to be imported into the input signal of driving circuit 77, and Figure 15 represents from the output signal of driving circuit 77 outputs.Figure 14 (A) makes to be driven the input signal of parts 516 to the mobile time input near the direction (right among Figure 11) of piezoelectric element 12, and Figure 14 (B) makes to be driven parts 516 to the input signal of input when mobile away from the direction of piezoelectric element 12 (in Figure 11 for left to).In addition, Figure 15 (A) makes to be driven the output signal of parts 516 to the mobile time output near the direction (right among Figure 11) of piezoelectric element 12, and Figure 15 (B) makes to be driven parts 516 to the output signal of output when mobile away from the direction of piezoelectric element 12 (in Figure 11 for left to).

The output signal of Figure 15 (A), (B) is the pulse signal that carries out the high-low level conversion with the input signal of Figure 14 (A), (B) at synchronization.2 signals among Figure 15 (A), (B) are imported into input terminal 72A, the 72B of piezoelectric element 12.Though also can import the signal that constitutes by platform shape waveform shown in Figure 2,, can make piezoelectric element 12 actions by input rectangular shape pulse signal as shown in figure 15 to this input terminal 72A, 72B.In this case, because the drive signal of piezoelectric element 12 gets final product for the rectangular shape pulse signal, so generate signal easily.

The output signal of Figure 15 (A), (B) is made of the pulse signal of 2 rectangular shapes that become same frequency.These 2 pulse signals by making mutual phase place difference, and become the signal that the potential difference (PD) of mutual signal increases interimly and sharply reduces, or the potential difference (PD) signal that increases sharp and reduce interimly.By importing 2 such signals, can make the elongation speed of piezoelectric element 12 different with contraction speed, be driven parts 516 and move thereby can make.

For example, in Figure 15 (A), (B), after being set at signal a side and becoming H (high level) and drop to L (low level) then, make the opposing party's signal become H.In these signals, when a side signal becomes L, postponing t through the regular hour _OFFAfter make the opposing party's signal become H.In addition, all be under the situation of L at 2 signals, then become OFF state (dummy status) as output.

For the output signal of this Figure 15 (A), (B), that is, make the electric signal of piezoelectric element 12 actions, use the frequency signal of super audible frequency.In Figure 15 (A), (B), the frequency of 2 signals is used the frequency signal of super audible frequency.For example frequency of utilization is the signal of 30kHz～80kHz, and the better frequency that is to use is the signal of 40kHz～60kHz.By using the signal of such frequency, can reduce the action sound of piezoelectric element 12 in zone of audibility.

Below, the action of the drive unit of present embodiment is described.

In Figure 11, electric signal is imported into piezoelectric element 12, by the input of this electric signal, piezoelectric element 12 is extended repeatedly and shrinks.To extending and shrink, driver part 14 moves back and forth.At this moment, different by the elongation speed that makes piezoelectric element 12 with contraction speed, can make driver part 14 to the translational speed of certain orientation with different to its reciprocal translational speed.Thus, can make and be driven parts 516 and moving lens 70 moves to desirable direction.

When piezoelectric element 12 stretches, generation is based on this flexible vibration, but support by the direction of support component 60 owing to comprise the actuator 510 of piezoelectric element 12, so the flexible vibration that is produced of piezoelectric element 12 is not easy to be passed to the outside of actuator 510 from direction quadrature flexible with it.Therefore, can suppress actuator 510 and form resonance, and can reduce the influence of this resonance with main body 24 external components such as grade.Thereby, can make to be driven parts 516 and moving lens 70 and correctly to move.

As mentioned above, in the drive unit 500 of present embodiment, by making control part 71 to satisfy f 〉=2 ^1/2F ₀Driving frequency f drive pressure electric device 12, can reach the effect identical with above-mentioned embodiment.That is, can reach the resonance that prevents piezoelectric element 12, guarantee the action effect of stable drive amount all the time.

In addition,, make between actuator 510 and external component, to be not easy transmitting vibrations, can reduce the influence of resonance thus by supporting actuator 510 from direction with the flexible direction quadrature of piezoelectric element 12.Thereby can make and be driven parts 516 and moving lens 70 and correctly move.In addition, the detecting device 75 that detects the shift position be driven parts also can be applicable in other embodiment certainly.

In addition, above-mentioned each embodiment has only illustrated an example of drive unit of the present invention.Drive unit of the present invention is not limited to the related drive unit of these embodiments, in the scope that does not change dominant technology thought of the present invention, also can the drive unit of embodiment be changed, or the enforcement on other purposes.

In addition, in the present invention, though as described above, the soft hammer parts of preferred use, even but under the situation of having used rigid hammer parts, by in above-mentioned scope, using driving frequency f, also can reach the influence that inhibition is caused because of resonance, be driven that parts are stable correctly to be moved thereby can make.

In addition, as the purposes of actuator of the present invention, for example, can be applicable in the miniature precision machines such as digital camera and mobile phone.Mobile phone particularly, the actuator of the application of the invention can make to be driven parts to move more than or equal to the high-speed of 2mm/s.Thus, even need zoom lens that move about 10mm, also can promptly move.In addition,, be not limited to the purposes of moving lenss such as mobile focusing lens and zoom lens, also can be used for the purposes of mobile CCD etc. as the purposes of actuator of the present invention.

In addition, for example in the 5th embodiment, to the situation of drive unit of the present invention as the drive unit that drives moving lens 70 is illustrated, but also can be as the drive unit that drives the object beyond the moving lens 70.

Claims (14)

1. drive unit, it is characterized in that, it has actuator, this actuator, link by the electricapparatus conversion element, with an end of described electricapparatus conversion element and corresponding described electricapparatus conversion element flexible and driver part that moves and the hammer parts that are arranged on the other end of described electricapparatus conversion element constitute, and the parts that are driven with described driver part frictional engagement are moved along described driver part; Also has the driving circuit that is used to drive described actuator; Described driving circuit, described electricapparatus conversion element and described driver part as quality and in 1 system without constraints of described hammer parts as spring, resonant frequency is being made as f ₀, when the driving frequency of described electricapparatus conversion element is made as f, to become f 〉=2 ^1/2F ₀Driving frequency f, drive described electricapparatus conversion element.

2. drive unit according to claim 1 is characterized in that, described resonant frequency f ₀For: f ₀≤ 70kHz.

3. drive unit according to claim 1 and 2 is characterized in that, the modulus of longitudinal elasticity of the material of described hammer parts is lower than the modulus of longitudinal elasticity of the material of described electricapparatus conversion element.

4. according to any described drive unit in the claim 1～3, it is characterized in that the modulus of longitudinal elasticity of the material of described hammer parts is below 1Gpa.

5. according to any described drive unit in the claim 1～4, it is characterized in that described hammer parts reduce parts by the resonant frequency of the resonant frequency that reduces described actuator and constitute.

6. drive unit according to claim 5 is characterized in that, reduces the hammer parts that parts constitute by being provided with by described resonant frequency, than the situation that the hammer parts that are made of rigid material are set, can reduce the resonant frequency of described actuator.

7. according to any described drive unit in the claim 1～6, it is characterized in that described driver part is supported for, its front and/or its base end side can move on the flexible direction of described electricapparatus conversion element.

8. according to any described drive unit in the claim 1～7, it is characterized in that the side from the flexible direction of described relatively electricapparatus conversion element is supported on described actuator on the basket.

9. according to any described drive unit in the claim 1～8, it is characterized in that also having driver element, its generation be used for driving described electricapparatus conversion element, at elongation and the asymmetrical signal of shrinkage direction.

10. according to any described drive unit in the claim 1～9, it is characterized in that the described parts that are driven contact with described driver part formation face.

11., it is characterized in that having the described detecting unit that is driven the shift position of parts of detection according to any described drive unit in the claim 1～10.

12. according to any described drive unit in the claim 1～11, it is characterized in that,, drive described electricapparatus conversion element to surpass the driving frequency of audible frequency.

13., it is characterized in that described parts and the optics of being driven links, and is used in the photographic optical system according to any described drive unit in the claim 1～12.

14., it is characterized in that described actuator is used in the photographic optical system set in the mobile phone according to any described drive unit in the claim 1～13.

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