KR20100134407A - Camera Module Using Piezo Actuator - Google Patents

Abstract

It relates to a camera module using a piezoelectric actuator. The camera module includes a lens unit including at least one lens, a barrel into which the lens unit is inserted, a piezoelectric body having an opening in a center of which is attached to a lower side of the barrel to receive current from the outside and expand or contract therein, and a lower portion of the piezoelectric body. Including an infrared filter that is located in close contact with the light transmitted through the lens unit in the infrared region, and an image sensor for converting the light filtered by the light in the infrared region into an electrical signal, when applying a current to the piezoelectric As the piezoelectric body expands or contracts, the barrel is linearly moved upward or downward to adjust the focus of the lens.

Description

Camera module using piezoelectric actuators

The present invention relates to a camera module, and more particularly, to a camera module using a piezoelectric actuator.

A piezoelectric actuator is a transducer that converts movable energy (electrical energy) into mechanical displacement or stress using a piezoelectric method, and is applied to a motor or other cylinder for adjusting zoom and focus in a camera module such as a mobile phone.

In general, the optical apparatus includes a lens transfer device for transferring the lens in the optical axis direction. The lens transfer device uses an actuator such as an electromagnetic motor or a piezoelectric actuator as a means for generating power, and transmits the power generated by the actuator. Use a cam or screw as a means of doing so. Therefore, such a lens transfer device implements an auto focus function by adjusting the focal length by transferring the lens in the optical axis direction by using the power generated from the actuator.

Such piezoelectric actuators have various advantages, such as miniaturization, high resolution, low noise, and low noise, compared to conventional electromagnetic motors. When implementing the focus adjustment function, two piezoelectric actuators are attached to both sides of the lens transfer device, there is a problem that the tilt of the lens due to the imbalance of the contraction or expansion of the two piezoelectric actuators may occur.

The technical problem to be achieved by the present invention is to provide a camera module for implementing a focus control function using a piezoelectric actuator that can provide a balanced contraction or expansion.

 According to an aspect of the present invention, a lens unit including at least one lens, a barrel in which the lens unit is inserted, a piezoelectric body having an opening in a center attached to a lower side of the barrel to receive or receive an electric current from outside, And an infrared filter positioned in close contact with the lower part of the piezoelectric body and filtering the light in the infrared region from the light transmitted through the lens unit, and an image sensor for converting the light filtered by the light in the infrared region into an electrical signal. When the current is applied, the piezoelectric member expands or contracts, thereby providing a camera module for adjusting the focus of the lens by linearly moving the barrel upwards or downwards.

Compared to the conventional camera module using two piezoelectric actuators, the tilt of the lens due to the imbalance of contraction or expansion can be reduced. Contamination of foreign substances due to the connection of various elements such as the barrel protecting the lens, the piezoelectric and barrel connecting parts, and the piezoelectric body can be minimized.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers, such as second and first, may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as the first component, and similarly, the first component may also be referred to as the second component.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the same or corresponding components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted.

1 is a cross-sectional view showing an example of a camera module having an auto focus adjustment function using a piezoelectric actuator.

Referring to FIG. 1, the camera module 100 having an auto focus adjustment function includes a lens unit 110, a barrel 120, two piezoelectric members 130, a barrel transfer unit 140, and an infrared filter ( 151, an image sensor 153, a printed circuit board 155, a first holder 160, a second holder 170, and a housing 180.

The lens unit 110 includes a blocking member 113 for blocking light between the plurality of lenses 111 and the plurality of lenses 111 and a spacer 115 for maintaining a gap between the plurality of lenses 111. do.

The barrel 120 has a function of protecting the lens unit 110 by inserting the lens unit 110, and a thread 123 is formed on the lower outer side thereof. The two piezoelectric members 130 receive electric energy from the outside through the conductive wire 133, and are attached to both sides of the barrel transfer part 140, which will be described below. Converts into stresses and expands or contracts.

The barrel transfer part 140 has a thread 135 corresponding to the thread 123 formed on the barrel 120 and is formed therein so that the barrel transfer part 140 is coupled to the barrel 120 through the thread 135 and attached to the upper side. In accordance with the expansion or contraction of the 130, the linear movement in the vertical direction to move the barrel 120 is inserted into the lens unit 110 coupled through the thread 135 is linearly moved in the vertical direction. The focal point of the lens 111 is adjusted by controlling the expansion or contraction of the piezoelectric body 130 by adjusting the electrical energy input to the piezoelectric body 130.

The infrared filter 151 is positioned in the support part 163 extending from the first holder 160 whose bottom surface is attached to and supported by the adhesive on the printed circuit board 155 described below in the lower part of the lens part 110. The light of the infrared region is filtered from the optical image received by the lens unit 110 and irradiated to the image sensor 153.

The bottom surface of the second holder 170 is attached above the first holder 160, and the second holder 170 has a barrel conveying part on its upper surface when the barrel conveying part 140 linearly moves downward. The bottom surface of the 140 may be in contact, and the barrel conveyance unit 140 serves as a support according to the linear movement in the upward or downward direction. In addition, a bottom surface of the housing 180 having an upper portion extending in a horizontal direction above the edge side of the first holder 160 is attached, and a piezoelectric body 130 is formed inside the horizontally extending portion of the housing 180. Contact. The housing 180 serves as a support for supporting the connected second holder 170, the barrel transfer unit 140, and the piezoelectric body 130, respectively.

The image sensor 153 is spaced apart from the lower portion of the infrared filter 151 and converts the optical image from which light in the infrared region is filtered into an electrical signal. Here, the image sensor 153 and the lens unit 110 are optically aligned with the image sensor 153. The printed circuit board 155 is provided with a predetermined electrical pattern and a plurality of electrodes (not shown). The printed circuit board 155 is attached to the back of the image sensor 153 by an adhesive such as epoxy, and is connected to the image sensor 153. It is electrically connected by bonding wires 157.

As such, when two piezoelectric actuators are attached to both sides of the lens transfer device, tilting of the lens may occur due to an imbalance in contraction or expansion of the two piezoelectric actuators.

2 is a cross-sectional view showing a camera module having an auto focus adjustment function using a piezoelectric actuator according to the present embodiment.

Referring to FIG. 2, the camera module 200 includes a lens unit 210, a barrel 220, a piezoelectric body 230, a spring 240, an infrared filter 251, an image sensor 253, and a printed circuit board 255. ), A holder 260 and a housing 270.

The lens unit 210 includes a blocking member 213 for blocking light between the plurality of lenses 211 and the plurality of lenses 211 and a spacer 215 for maintaining a gap between the plurality of lenses 211. do.

The barrel 220 serves to protect the lens unit 210 by inserting the lens unit 210, and moves linearly in the vertical direction in accordance with the expansion or contraction of the piezoelectric member 230 described below attached to the lower side. The inserted lens unit 210 is linearly moved in the vertical direction.

The piezoelectric body 230 has an opening in the center so that the optical image received by the lens unit 210 can pass therethrough. The piezoelectric member 230 is attached to the lower side of the barrel 220 and receives electrical energy from the outside through the conductive wire 233. It receives the input and converts electrical energy into mechanical displacement or stress to expand or contract. The focal point of the lens 211 is adjusted by controlling the expansion or contraction of the piezoelectric body by adjusting the electric energy input to the piezoelectric body 230. Here, the piezoelectric body may be used for various functions of transferring the lens unit 210 in the optical axis direction, such as a zoom adjustment function as well as an auto focus adjustment function.

3 is a perspective view of a piezoelectric body according to the present embodiment.

Referring to FIG. 3, the piezoelectric member 230 has an opening in the center thereof so that the optical image received by the lens unit 210 may pass therethrough. Here, the piezoelectric body 230 may have various shapes as long as it has a ring shape having an opening in the center thereof. Preferably, in addition to the ring shape as shown, it may be a variety of symmetrical shapes, such as a square having an opening in the center.

Referring back to FIG. 2, the infrared filter 251 is positioned to contact the piezoelectric member 230 at the bottom of the piezoelectric member 230, and the bottom surface of the infrared filter 251 is attached to the printed circuit board 255 to be described below through an adhesive. Located in the support 263 extending from the holder 260 is filtered in the infrared region in the optical image received by the lens unit 210 and irradiated to the image sensor 253. The bottom surface of the housing 270 extending in the horizontal direction is attached to the top of the corner side of the holder 260, the spring 240 is attached to the inside of the horizontally expanded portion of the upper portion of the housing 270. . The spring 240 provides an elastic force as the barrel 220 moves linearly in the vertical direction.

The image sensor 253 is spaced apart from the lower portion of the infrared filter 251 and converts the optical image from which light in the infrared region is filtered into an electrical signal. The printed circuit board 255 is provided with a predetermined electrical pattern and a plurality of electrodes (not shown). The printed circuit board 255 is attached to the back of the image sensor 253 by an adhesive such as epoxy, and is connected to the image sensor 253. It is electrically connected by bonding wires 257.

Although the present invention has been described above with reference to the embodiments, it will be apparent to those skilled in the art that the present invention may be modified and changed in various ways without departing from the spirit and scope of the present invention. I can understand. Therefore, it is not intended that the invention be limited to the above-described embodiments, but the present invention will include all embodiments within the scope of the following claims.

1 is a cross-sectional view showing an example of a camera module having an auto focus adjustment function using a piezoelectric actuator.

2 is a cross-sectional view showing a camera module having an auto focus adjustment function using a piezoelectric actuator according to the present embodiment.

3 is a perspective view of a piezoelectric body according to the present embodiment.

<Explanation of symbols for the main parts of the drawings>

210: lens unit 211: lens

213: blocking member 215: spacer

220: barrel 230: piezoelectric body

240: spring 251: infrared filter

253: image sensor 255: printed circuit board

257: bonding wire 260: holder

270: housing

Claims (4)

A lens unit including at least one lens; A barrel into which the lens unit is inserted; A piezoelectric body attached to the lower side of the barrel and expanded or contracted by receiving current from the outside and having an opening in a center thereof; An infrared filter positioned under the piezoelectric body and filtering light in an infrared region from light transmitted through the lens unit; And It includes an image sensor for converting the light filtered in the infrared region into an electrical signal, And applying a current to the piezoelectric body to expand or contract the piezoelectric body so that the barrel linearly moves upward or downward to adjust the focus of the lens. The method of claim 1, The top of the barrel camera module further comprises a spring to provide an elastic force when the barrel is moved in a straight direction upward or downward. The method of claim 1, And a printed circuit board closely attached to the rear surface of the image sensor and electrically connected to the image sensor. The method of claim 1, And the piezoelectric body has a ring shape having an opening in a center thereof.

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