Lens module

A lens module includes a lens, a barrel, a holder and a driving mechanism. The barrel is configured for receiving the lens. The holder is configured for receiving the barrel therein. The driving mechanism includes a first lever and a first piezoelectric device. The first lever includes a fixed end and a moving end and a connecting portion interconnected between the fixed end and the moving end. The fixed end of the first lever is pivotedly mounted in the holder. The moving end of the first lever is configured for driving the barrel to move. The first piezoelectric device is arranged between the connecting portion and the holder. The first piezoelectric device is extendable and contractible along an optical axis of the lens so as to control movement of the barrel along the optical axis relative to the holder.

BACKGROUND

1. Technical Field

The present disclosure generally relates to lens modules, particularly, to a lens module having a piezoelectric driving mechanism.

2. Description of Related Art

With the ongoing development of microcircuitry and multimedia technology, cameras, including still cameras and digital cameras are now in widespread use combined with various electronic devices. These cameras often feature autofocus and zoom functions.

Lens modules are key camera components. Driving mechanisms, such as step motors, have recently been integrated into the lens modules for moving the lenses, to provide autofocus and zoom function. However, the step motor is generally relatively bulky and heavy when applied to a single lens, and, in addition, consumes a substantial amount of power, especially relative to the capabilities of a typical battery system of a camera or electronic device.

What is needed, therefore, is a lens module which has a simple and energy-efficient driving mechanism.

DETAILED DESCRIPTION OF THE DISCLOSURES

Referring toFIG. 1, a lens module10in accordance with a first embodiment of the present disclosure includes a barrel20, a holder30, and two driving mechanisms40for the barrel20.

The barrel20receives at least one lens21fixed to the inner surface by adhesive. The lens21has an optical axis OO′. An outer surface of the barrel20is smooth. Two connecting arms22extend horizontally from a top end of the barrel20.

The holder30includes a receiving chamber301receiving the barrel20therein. A surface of the receiving chamber301is smooth. The barrel20moves along the optical axis OO′ of the lens21toward the holder30.

Referring toFIG. 3, the driving mechanism40includes a first lever41a, a second lever41b, a third lever41c, a first support42a, a second support42b, a third support42c, a bottom plate43, a first piezoelectric device44a, a second piezoelectric device44b, and a third piezoelectric device44c.

Lever41aincludes a fixed end411a, a moving end412a, and a connecting portion413a. The connecting portion413ais interconnected between the fixed end411aand the moving end412a. The moving end412ais higher than the fixed end411a. Lever41bincludes a fixed end411b, a moving end412b, and a connecting portion413b. The connecting portion413bis interconnected between the fixed end411band the moving end412b. The moving end412bis higher than the fixed end411b. Lever41cincludes a fixed end411c, a moving end412c, and a connecting portion413c. The connecting portion413cis interconnected between the fixed end411cand the moving end412c. The moving end412cis higher than the fixed end411c. Guide rails431aand431bare mounted on the bottom plate43. A groove4311ais defined on a side of arm431a. A groove4311bis defined on the opposite side of arm431b. The grooves4311aand4311breceive the levers41a,41b, and41c. The bottom plate43and guide rails431aand431bcan be integrally formed.

The first support42ais mounted on the bottom plate43. The fixed end411aof the first lever41ais pivotedly mounted on the first support42a. The second support42bis mounted on the moving end412aof the first lever41a. The fixed end411bof the second lever41bis pivotedly mounted on the second support42b. The third support42cis mounted on the moving end412bof the second lever41b. The fixed end411cof the third lever41cis pivotedly mounted on the third support42c. Thus, the moving end412a,412bor412cof each lever41a,41bor41cis rotated in the grooves4311a,4311bto move the barrel20along the optical axis OO′ of the lens21.

The first piezoelectric device44ais arranged between the bottom plate43and the connecting portion413aof the first lever41a. The second piezoelectric device44bis arranged between the fixed portion412aof the first lever41aand the connecting portion413bof the second lever41b. The third piezoelectric device44cis arranged between the fixed portion412bof the first lever41band the connecting portion413cof the second lever41c. The piezoelectric devices44a,44b, and44care electrostrictive material such as piezoelectric ceramic, and can be cylindrical.

In assembly, the two driving mechanisms40are fixed to the holder30. The grooves4311a,4311bof the guide rails431a,431bare parallel with the optical axis OO′ of the lens21. The two connecting arms22of the barrel20are fixed to the two moving ends412cof the two third levers41c. The two driving mechanisms40move the barrel20along the optical axis OO′ of the lens21in the holder30. Each piezoelectric device44a,44bor44cgenerates mechanical deformation when voltage is applied to each piezoelectric device44a,44bor44c. Each piezoelectric device44a,44bor44crotates the moving end412a,412bor412cto be extendable and contractible along the optical axis OO′ of the lens21so as to control movement of the barrel20along the optical axis OO′ relative to the holder30. A position sensor4312is mounted in a top end of the groove4311ato avoid overshoot of the moving end412cof the third lever41c. The position sensor4312includes an optical transmitter43121and an optical receiver43122receiving the light.

When voltage application ceases, the moving end412cof the third lever41cmoves over position sensor4312, which signals the driving mechanism40not to apply voltage. The length of each piezoelectric device44a,44bor44cis restored, returning the moving end412cof the third lever41cto the original position. The driving mechanism40applies a lower voltage to each piezoelectric device44a,44bor44cto avoid overshoot of the moving end412cof the third lever41c.

Referring toFIGS. 4 and 5, an exemplary lens module10ain accordance with a second embodiment of the disclosure includes a barrel20a, a holder30a, two driving mechanisms40aand a supporting member50supporting the two driving mechanisms40a.

The barrel20aand the holder30aare both cylindrical. The lens barrel20ahas an outer thread201formed thereon. The holder30ahas an inner thread302formed therein. The lens barrel20ais threaded with the holder30a. A lens assembly202is received in the barrel20a. The lens assembly202has an optical axis AO′. The lens assembly202includes a first retaining ring203receiving a first lens2021and a second retaining ring204receiving a second lens2022.

Two connecting arms2031horizontally extend from the first retaining ring203respectively. The two connecting arms2031are fixed to the two driving mechanisms40arespectively. The two driving mechanisms40amove the barrel20aalong the optical axis AO′ in the holder30a. Two connecting arms2041horizontally extend from the second retaining ring204respectively. The two connecting arms2041are fixed to the barrel20arespectively.

The supporting member50is an annular plastic plate with a hole defined in the center thereof. The supporting member50is received in the barrel20aand secured to the inner wall of the barrel20a. The two driving mechanisms40aare fixed to the supporting member50. The two driving mechanisms40amove the first lens2021along the optical axis AO′ of the lens assembly202in the barrel20a.

Referring toFIG. 6, an exemplary driving mechanism40bof the lens module (not shown) in accordance with a third embodiment is provided, differing from driving mechanism40only in that the driving mechanism40bincludes a first lever410, a first support420, a first piezoelectric device440and a bottom plate430b. The first support420is mounted on the bottom plate430b. The first lever410is pivotedly mounted on the first support420. The first piezoelectric device440is arranged between the bottom plate430band the first lever410.

Referring toFIG. 7, an exemplary driving mechanism40cof the lens module (not shown) in accordance with a fourth embodiment, differing from the driving mechanism40only in that the driving mechanism40bincludes a first lever4100a, a second lever4100b, a first support4200a, a second support4200b, a first piezoelectric device4400a, a second piezoelectric device4400band a bottom plate430c. The first support4200ais mounted on the bottom plate430c. One end of the first lever4100ais pivotedly mounted on the first support4200a. The first piezoelectric device4400ais arranged between the bottom plate430cand the end of the first lever4100a. The second support4200bis mounted on the other end of first lever4100a. The second lever4100bis pivotedly mounted on the second support4200b. The second piezoelectric device4400bis arranged between the other end of the first lever4100aand the second lever4100b.

Referring toFIG. 8, an exemplary driving mechanism40dof the lens module (not shown) in accordance with a fifth embodiment is provided, differing from the driving mechanism40conly in that a fixed end41001bof a second lever41000bis pivotedly mounted on the moving end41002aof a first lever41000awith no support.

It is to be understood that the described embodiments are intended to illustrate rather than limit the disclosure. Variations may be made without departing from the spirit of the disclosure as claimed. The above-described embodiment illustrates the scope of the disclosure but do not restrict the scope of the disclosure.