KR101172077B1 - Camera module - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera module, and more particularly, to a camera module capable of adjusting focus by varying a distance between a lens and an image sensor chip using a longitudinal deformation of a shape memory alloy.

The camera module according to the present invention comprises an image sensor chip having an image sensing unit, a lens for focusing light to the image sensing unit, a lens barrel for fixing the lens, and light between the lens and the image sensing unit of the image sensor chip. And an outer housing incorporating them to form a path, and focus shifting means for changing the focal length between the image sensing unit and the lens by moving the lens and the lens barrel with respect to the image sensor chip.

In addition, the focus shifting means of the camera module according to the present invention is characterized in that the shape memory alloy.

Camera, Module, Focus Movement Device, Shape Memory Alloy

Description

Camera module {Camera module}

1 is a longitudinal sectional view schematically showing the structure of a conventional camera module,

2 is an exploded perspective view for explaining the configuration of a camera module having a focus shifting means formed of a shape memory alloy according to the present invention;

3 is a partial cutaway cross-sectional view for explaining the installation relationship of the focus shifting means of the shape memory alloy shown in FIG.

4A and 4B are longitudinal cross-sectional views for explaining step-by-step driving processes of a camera module having a focus moving means formed of the shape memory alloy shown in FIG. 2, respectively.

Description of the Related Art [0002]

10, 100: camera module 11, 110: printed circuit board

15, 150: lens 16, 160: lens barrel

170: leaf spring 12, 120: image sensor chip

190: focus shift means 180: outer housing

162: barrel guide 22, 124: image sensing unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera module, and more particularly, to a camera module capable of adjusting focus by changing a distance between a lens and an image sensor chip using a longitudinal change of a shape memory alloy.

The compact camera module is generally embedded in a portable electronic device such as a wireless terminal or a PDA, which is required for portability, and is light and simple, and enables the capturing, storing, and transmitting of images through mounted electronic equipment.

The general camera module 10 includes an image sensor chip 12 for converting an optical signal into an electrical signal, a lens 15 for condensing light with the image sensor, and the image sensor chip as shown in FIG. 1. It includes a printed circuit board 11 is formed a circuit pattern for processing the signal.

The image sensor chip 12 has an image sensing unit 22 for converting an image of an object into an electric signal at the center thereof, and the lens 15 is attached to the inside of the lens barrel 16 for fixing the printing. It is coupled to an upper surface of the housing 13 located on the upper surface of the circuit board 11. In addition, an IR (infrared ray) filter 14 is attached to the inside of the housing 13.

At this time, the lens 15 is a device for refracting the light so as to attract a large amount of light from one point of the subject to gather at one point, so that the light running in a straight line from any one point is gathered in one place while passing through the lens. When the light is gathered to form an image, the distance between the lens 15 and the image sensing unit 22 of the image sensor chip 12 forming the image is a focal length.

That is, the focal length is a distance between the lens and the water surface of the image sensing unit, and the conventional camera module 10 has the focal length fixed due to technical problems and limitations such as thickness.

In this case, when the subject is located at a long distance, and when a wider screen is to be taken, the conventional camera module cannot change the distance between the lens 15 and the image sensor chip 12, so that the image sensor chip ( 12) the image formed by the image sensing unit 22 on the image is out of focus and a good image cannot be obtained.

That is, in order to obtain a good image, it is required to focus the light on the image sensing unit by adjusting the position of the lens at various focal lengths according to the position of the subject. / A driving source for electrically moving the lens has been installed in the camera module.

These driving sources (not shown) are compact and lightweight according to the size of the camera module, and must be finely driven so that they can be focused in real time when zooming, so that piezo-piezoelectric, stepping motor, Voice coil motors (VCMs) are commonly used.

However, a drive source such as a piezo motor is disposed around the lens barrel to move the position of the lens. However, since the drive source is driven by a mechanical / electronic mechanism, it is small but has a constant volume. Becomes larger than before.

The camera module manufactured in the form of mounting at a specific position of the wireless terminal is a camera module because the volume of the camera module, which is very limited in volume depending on the size of the portable terminal manufactured according to the needs of light and small, increases in weight and increases in weight. Can't be made very small.

In addition, the productivity of the driving source is not high and the price is expensive because of the mechanically complicated configuration.

The camera module according to the present invention provides a camera module that can change the focal length by moving the lens barrel of the camera by using a change in the length of the shape memory alloy.

The present invention provides a camera module that is thinner and lighter by manufacturing a camera module capable of changing a focal length without using a driving source.

The camera module according to the present invention includes an image sensor chip having an image sensing unit, a lens for focusing light to the image sensing unit, a lens barrel for fixing the lens, and a view between the lens and the image sensing unit of the image sensor chip. And an outer housing incorporating them to form a furnace, and focus shifting means for changing the focal length between the image sensing unit and the lens by moving the lens and the lens barrel with respect to the image sensor chip.

In addition, the focus shifting means of the camera module according to the present invention changes in the longitudinal direction and moves the lens and the lens barrel with respect to the image sensor chip according to the change.

Furthermore, the focus movement means of the camera module according to the present invention is made of a shape memory alloy.

Hereinafter, embodiments of a structure and a driving method of a camera module capable of adjusting focus using a shape memory alloy according to the present invention will be described in detail with reference to the accompanying drawings.

2 is an exploded perspective view illustrating the configuration of a camera module having a focus shifting means formed of a shape memory alloy according to the present invention, and FIG. 3 is an installation relationship of the focus shifting means of a shape memory alloy shown in FIG. A partial cutaway cross-sectional view to illustrate.

4A and 4B are longitudinal cross-sectional views for explaining step-by-step driving processes of the camera module having the focus moving means formed of the shape memory alloy shown in FIG. 2, respectively.

As shown in FIG. 2, the camera module 100 according to the present invention includes an image sensor having an electrode pad and an image sensing unit 124 formed of a pixel including a photodiode and a transfer transistor for transmitting a signal of the photodiode. A chip 120 and a circuit board 110 is formed with a circuit pattern for receiving the image signal generated by the image sensor chip 120.

In addition, an IR filter housing 130 having the IR filter 140 fixed therein is positioned on the image sensor chip 120 so that the IR filter 140 is positioned on the image sensor chip 120. The lens barrel 160 having one or more lenses 150 is installed at an upper portion thereof.

The outer housing 180 forming the path of the light flowing between the image sensing unit 124 and the lens 150 has the lens barrel 160 and the IR filter housing 140 embedded therein to form the printed circuit board 110. )

In this case, the camera module 100 according to the present invention may move the lens barrel 160 in which the lens 150 is built in the longitudinal direction to move the position of the lens with respect to the image sensor chip 120. Focus shifting means 190.

The focal shifting means 190 according to the present invention is a shape memory alloy which can be deformed in a longitudinal direction, and moves the lens barrel 160 by a predetermined range in the longitudinal direction inside the outer housing 180.

To this end, the inner peripheral surface of the outer housing 180, as shown in Figure 3, a plurality of stepped grooves (such as a length that can ensure the correct focal length between the lens 150 and the image sensor chip 120) 182 is formed.

In addition, as illustrated in FIGS. 2 and 3, a plurality of lens barrel guide grooves 162 are formed in the longitudinal direction outside the lens barrel 160. Here, the number of the stepped grooves 182 and the lens barrel guide grooves 162 are the same in plural, and are formed at opposite positions, respectively.

For example, in the case of the shape memory alloy manufactured in the form of a wire, the focus shifting means 190 according to the present invention has one end 191 and the lens connected to an upper portion of the inner stepped groove 182 of the outer housing 180. Body 193 coupled in the longitudinal direction inside the barrel guide groove 162 and the other end fixed to the lower end of the lens barrel 162 to lift the lens barrel 160 in the longitudinal deformation of the shape memory alloy And 192.

In this case, although not shown, one end 191 of the focus movement means 190 may be inserted into and fixed to the stepped groove 182 of the outer housing 180.

In addition, the other end 192 of the focus shifting means 190 is bent at its end so that the other end of the focus shifting means is connected to the lower end of the lens barrel 160 so that the overall shape is “L” or “c” shaped. It can be formed as.

The other end 192 of the focus shifting means 190 of the bent portion is fitted into a long hole (not shown) formed on the lower surface of the lens barrel 160 while being bent.

That is, one end of the focus shifting means 190 formed of the shape memory alloy according to the present invention is fixed inside the outer housing 180, and the other end 192 is fixed to the bottom surface of the lens barrel 160. When bending the other end 192 of the shape memory alloy for smooth assembly, unlike the bent portion, the body 193, which is a non-bent portion, is processed to have its own restoring force in the longitudinal direction.

The focal shifting means 190 is subjected to shape memory heat treatment so as to return to its original length at or above the critical temperature even if it has a length that is physically deformed (bent, distorted, or bent) by an external force through the shape memory heat treatment.

That is, the shape memory alloy, for example, when using a shape memory alloy wire having a diameter of 200 ㎛ containing 50% Ti, 50% (atomic ratio), by adding a pre-strain to the shape memory alloy By generating a compressive residual stress in the base metal, it is processed into a wire form as a material that can further improve the mechanical properties of the metal composite material, such as imparting high tensile strength that has not been obtained in conventional metal composite materials.

That is, the focal shifting means 190 made of the shape memory alloy is physically deformed when the current is applied to return to the original length from the extended length, and is returned to the physically deformed length when the current is not applied.

In the embodiment of the present invention, since the focal length is set to 2 mm, the longitudinal deformation amount and the strain stress required for the focal moving means 190 may be derived according to the weight of the lens barrel.

For example, a lens barrel with a built-in lens installed in a general camera module having 2 million pixels has a weight of about 0.1g, and thus a force of about 0.5g / force per second is required to change the focal length by moving it. .

On the other hand, the elastic force by the leaf spring 170 on the upper surface of the lens barrel 160 to control the movement interval of the lens barrel by providing a repulsive force to the focus movement means 190 made of a shape memory alloy Is added.

On the other hand, the focus shifting means 190 made of a shape memory alloy according to the present invention is not shown in the drawing because only a very small size of operation can be obtained assuming a 2% allowable deformation when the wire is used as it is, but the diameter is 1 mm. The shape memory alloy wire may be manufactured in the form of a spiral spring having a diameter of 10 mm and a pitch of 1 mm.

By moving the lens barrel in the longitudinal direction by using the focal shifting means 190, a drive source such as a motor may not be additionally installed in the camera module, so that the camera module can be reduced in size and weight.

Referring to the assembly process and the driving process of the camera module is installed in the focus memory means formed of a shape memory alloy according to the present invention as follows,

The camera module 100 according to the present invention applies epoxy on the upper surface of the circuit board 110 and mounts the image sensor chip 120 thereon, and then the electrode of the image sensor chip and the circuit board. Electrically connect the electrodes.

The IR filter housing 130 having the IR filter 140 mounted therein is fixed on the printed circuit board 110 so that the IR filter 140 is positioned inside the image sensor chip 120.

Meanwhile, after fixing the lens 150 in the lens barrel 160, the lens barrel is assembled to be movable in the longitudinal direction in the outer housing 180.

As shown in FIG. 3, the lens barrel 160 is assembled in the stepped groove 182 formed on the inner surface of the outer housing 180, and a leaf spring is formed on the upper surface of the lens barrel 160. 170 is positioned to adjust the moving distance of the lens barrel.

In addition, the focus shifting means 190 for shifting the position of the lens barrel 160 fixes one end of the focus shifting means 190 to an inner surface of the outer housing 180, and guides the body 193 to the lens barrel. Buried along the groove 162, the other end 192 is fixed to the lower surface of the lens barrel.

Accordingly, a focus shifting means 190 is formed on the longitudinal side surface of the lens barrel 160 so as to move the lens barrel, and the upper surface of the lens barrel 160 is adapted to the longitudinal movement of the lens barrel 160. Accordingly, the spring force by the leaf spring 170 may be applied.

In the camera module 100 as described above, light running in a straight line from a certain point is gathered in one place while passing through the lens, and the light is gathered to form a single image, wherein the image sensor chip 120 forms an image with the lens. The focal length, which is a distance from the surface of the image sensing unit 124, is formed.

This focal length varies as the lens barrel is moved, as shown in FIGS. 4A and 4B.

As shown in FIG. 4A when no voltage is applied, the focal length D1 between the lens 150 and the image sensing unit 124 of the image sensor chip 120 is fixed.

The light obtained from the outside is imaged on the image sensing unit 124 of the image sensor chip 120 through the lens 150 and converted into an electrical signal, and the image signal is transferred to the printed circuit board 110 having the circuit pattern. Through the main body such as the terminal is processed and displayed.

When the distance of the subject is moved or changed, when the focal length cannot be changed because the distance focused in the lens 150 collects and forms a single image, the focus between the subject and the lens is changed. Blurry images are imaged on the image sensor chip.

Accordingly, in order to move the lens 150 forward by the moving distance of the subject, that is, when the focus shifting means 190 is provided with, for example, a shape memory alloy wire having a diameter of 1 mm, the focus shifting means is provided. A voltage of 3V is applied to 190.

When the voltage is applied, the length of the focus shifting means 190 changes linearly, one end of the focus shifting means 190 is fixed to the inner wall of the outer housing and the other end is fixed to the lens barrel 160 side. Therefore, the lens barrel 160 is lifted toward the leaf spring 170 according to the linear change of the wire.

Accordingly, in order to form an image of a large portion of the image sensor chip, the focal length D2 between the lens 150 and the image sensor chip 120 is long, so that a predetermined size of the image sensor chip has a wide area. The image can be imaged.

If the voltage is not applied to the focal shifting means 190, the shape memory alloy wire changes linearly to a pre-deformed length and extends to a position maintaining the original focal length D1, thereby fixing the The lens barrel 160 and the lens 150 are also moved together.

On the other hand, after fixing the focus shifting means of the shape memory alloy to one side of the lens barrel, the shape memory alloy spring is extended to an appropriate length, and the current is applied to measure the magnitude of the force and the change in temperature. After the removal, the displacement of the shape memory alloy spring is measured to determine the required force, length, and diameter of the shape memory alloy.

The shape memory alloy is made of thin film and wire shape of the shape memory alloy, and then heat treated at 400-600 ° C. using a NiTi wire (51at% Ni-49at% Ti) having a thickness of 1.04 mm, for its shape memory effect. Can be obtained.

In addition, the present invention may be fixed to the focus moving means 190 is inserted into the reverse of the above embodiment, the spring spring 170, which is an elastic body may be supported from the lower portion of the lens barrel. That is, the initial focal length of the lens barrel can be adjusted by fixing one end of the focus moving means to the lower end of the outer housing and fixing the other end to the upper end of the lens barrel. In addition, the present invention may not necessarily include an elastic spring, which is an elastic body, or may be replaced with another elastic material (eg, rubber) other than the elastic spring.

Although the technical idea of the camera module using the shape memory alloy of the present invention has been described above with the accompanying drawings, this is an exemplary embodiment of the present invention and is not intended to limit the present invention. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

As described in detail above, the camera module using the shape memory alloy of the present invention moves the position of the lens by using the shape memory alloy having a predetermined shape capable of longitudinal deformation. The manufacturing method is very simple, and the overall size and volume of the camera module can be made thinner and smaller.

In addition, the camera module using the shape memory alloy of the present invention has an excellent effect of eliminating the increase of the additional parts as it is applied to the existing components as it is, and at the same time reduce the additional cost.

In addition, the camera module using the shape memory alloy of the present invention can exclude the drive source consisting of mechanical parts can be reduced in weight by preventing the damage caused by impact.

In addition, the camera module using the shape memory alloy according to the present invention can be applied to a limited installation position in the light and simple electronic components without any difficulty, the production efficiency is improved.

Claims (11)

An image sensor chip having an image sensing unit, A lens for focusing light onto the image sensing unit; A lens barrel for fixing the lens; An outer housing therein for forming an optical path between the lens and the image sensing unit of the image sensor chip; A focus shifting means for moving the lens and the lens barrel with respect to the image sensor chip to change a focal length between the image sensing unit and the lens, One end of the focus shifting means is fixed to the inner circumferential surface of the outer housing, the other end is fixed to the lower surface of the lens barrel to move the lens barrel in the longitudinal direction in accordance with its longitudinal change. The method of claim 1, And the focus shifting means is changed in the longitudinal direction and moves the lens and the lens barrel with respect to the image sensor chip according to the length change. The method of claim 1, The focus moving means is a camera module, characterized in that made of a shape memory alloy. The method of claim 1, The lens module, characterized in that the lens barrel in which the lens is installed therein is coupled to the inner peripheral surface of the outer housing, a stepped groove formed to a length that can be moved by the lens focal length. The method of claim 1, The camera module, characterized in that the guide groove in which the focus movement means is installed is formed in the longitudinal direction on the outer circumferential surface of the lens barrel. delete The method of claim 1, The focus shifting means is preformed and has a length from a fixed end of the outer housing to a fixed end of the lower surface of the lens barrel. The method of claim 1, And the focus shifting means reduces the lens barrel and the lens from the image sensor chip by a predetermined distance according to an applied voltage. delete delete delete

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