CN100367064C

CN100367064C - Lens driving mechanism

Info

Publication number: CN100367064C
Application number: CNB2004100860184A
Authority: CN
Inventors: 徐懋仁; 游恒一; 许文财
Original assignee: HUAYU COMPUTER CO Ltd
Current assignee: HUAYU COMPUTER CO Ltd
Priority date: 2004-10-22
Filing date: 2004-10-22
Publication date: 2008-02-06
Anticipated expiration: 2024-10-22
Also published as: CN1763577A

Abstract

The present invention relates to a lens driving mechanism which is provided with a lens sleeve for covering a lens. The outer surface of the lense sleeve is surrounded and fixed with a conductor coil which is surrounded by a spring. A magnet is opposite to the conductor coil, and the magnetic lines of the magnet face to and cut the conductor coil. At the moment, the conductor coil generates an action to drive the lens sleeve to move after a current passes the conductor coil. Adjusting the current magnitude on the conductor coil can control the strength of the action and the position of the lens sleeve.

Description

Lens driving mechanism

Technical Field

The present invention relates to a driving mechanism for a camera lens, and more particularly, to a driving mechanism for an auto-focusing camera lens.

Background

With the progress of the photographic technology, modern camera equipment mostly has a focusing function, so that objects at different distances can be clearly imaged in the camera. The focusing is to adjust the position of the lens so that the light entering the camera can be focused on the most correct position in the camera, and the captured image can be clearly recorded in the camera.

The earliest conventional cameras adopt a manual focusing mode, that is, the position of a lens is manually adjusted, and then the position of the lens is judged to be correct or not by naked eyes. Although it is easy to provide a satisfactory focusing result for a photographer by a manual focusing method, it is relatively difficult for a non-professional camera user to use the camera, and thus, a fully automatic camera has been developed. The full-automatic camera can automatically align the focal length when a photographer shoots an image, and then record the image, so that the use difficulty of the camera is reduced, and the probability of focusing failure is reduced by an automatic focusing mode.

In a simple auto-focusing method, a camera usually has a processor and a lens driving device. The processor captures the light signal and calculates the optimal position of the lens through some algorithms, and then moves the lens to the proper position through the lens driving device. The driving device can use a common rotary motor to achieve the purpose of moving the lens, but because the lens adopts a linear reciprocating type motion mode, a transmission mechanism capable of converting the rotary motion into the linear motion is required between the rotary motor and the lens. The transmission mechanism is generally composed of a cam sleeve and a gear device, is large in size and difficult to design, and has difficulty in application to portable products such as mobile phones and the like.

Furthermore, in view of the integration trend of electronic products, the camera is not a simple camera, but a portable device combined with a mobile phone or a Personal Digital Assistant (PDA), etc., so miniaturization of the design is also an important consideration. In the conventional lens driving method, the rotary motor not only occupies a considerable volume, but also takes the space occupied by the driving mechanism into consideration. Therefore, the miniaturization of the camera module is limited.

In view of the above, with the improvement of the requirements of focusing accuracy and product miniaturization, a more accurate, easier to control, and smaller lens driving mechanism is needed.

Therefore, it is obvious that the above conventional lens driving mechanism still has inconvenience and disadvantages in structure and use, and further improvement is needed. In order to solve the problems of the lens driving mechanism, the related manufacturers have tried to solve the problems without diligent efforts, but it has not been found that suitable designs are developed and completed for a long time, and general products have no suitable structure to solve the problems, which is obviously a problem that the related manufacturers want to solve.

In view of the above-mentioned drawbacks of the conventional lens driving mechanism, the inventor of the present invention has made extensive practical experience and professional knowledge for many years in designing and manufacturing such products, and has actively studied and innovated in cooperation with the application of theory to create a novel lens driving mechanism, which can improve the conventional lens driving mechanism and make it more practical. After continuous research and design and repeated trial production and improvement, the invention with practical value is finally created.

Disclosure of Invention

The present invention is directed to overcome the drawbacks of the conventional lens driving mechanism, and to provide a lens driving mechanism with a novel structure, which is more practical and has industrial utility due to high positioning accuracy, easy control, and small size.

The purpose of the invention and the technical problem to be solved are realized by adopting the following technical scheme. According to the present invention, a lens driving mechanism comprises: a lens barrel, wherein the inside of the lens barrel is enough to contain and fix a lens device and is provided with a flange which extends out from the outer surface of the lens barrel vertically; a conductor coil surrounding and fixed on the outer surface of the lens sleeve; an elastic device surrounding the lens sleeve; a mechanism sleeve, wherein the mechanism sleeve is sufficiently internal to accommodate the lens sleeve and the elastic device; and a magnetic device disposed on the inner surface of the mechanism sleeve, wherein each of the at least one magnet set is composed of a pair of magnets and a magnetic conductive material between the magnets, and the surfaces of the magnets and the magnetic conductive body have the same magnetism, wherein when the lens sleeve and the elastic device are disposed in the mechanism sleeve, the magnetic device is opposite to the conductive coil, so that when a current flows through the conductive coil, the conductive coil generates a force to drive the lens sleeve to move, and when the lens sleeve moves, the flange and the magnetic device simultaneously compress the elastic device from two ends of the elastic device, respectively, so that the elastic device generates a reaction force on the lens sleeve, and the intensity of the force can be controlled by adjusting the intensity of the current, so as to balance the reaction force and move the lens barrel to the required position.

The object of the present invention and the technical problems solved thereby can be further achieved by the following technical measures.

In an embodiment of the present invention, the outer surface of the lens barrel has a groove surrounding the lens barrel, and the conductive coil is fixed on the lens barrel in a manner of being wound in the groove.

In an embodiment of the present invention, the elastic device is a spring.

In the lens driving mechanism, the elastic device is a plate spring.

In the lens driving mechanism, the pair of magnets are neodymium (neodynium) iron boron magnets.

The lens driving mechanism further includes a zoom control circuit for controlling the magnitude of the current.

In the lens driving mechanism, the zoom control circuit is a processor.

Compared with the prior art, the invention has obvious advantages and beneficial effects. As can be seen from the above technical solutions, in order to achieve the above object, the main technical contents of the present invention are as follows:

the invention provides a lens driving mechanism, which consists of a first cylinder, a magnetic substance (a permanent magnet), a conductor coil, an elastic substance, a second cylinder and a lens device. The first cylinder and the second cylinder are hollow and have an opening at each end, wherein the first cylinder is large enough to surround the second cylinder. The second cylinder has a lens unit fixed inside, a conductor coil around and fixed on the outer surface of the second cylinder, and an annular flange extending perpendicularly from the outer surface of the second cylinder for bearing the elastic matter to surround the second cylinder. The magnetic substance is mounted on the inner surface of the first cylinder, and when the second cylinder enters the interior of the first cylinder, at least a portion of the conductive coil is opposite to the magnetic substance, i.e., at any time, at least a portion of the conductive coil is within the magnetic field lines of the magnetic substance, and the magnetic field lines of the magnetic substance pass through the conductive coil perpendicularly.

When current is applied to the conductor coil, the direction of the current is perpendicular to the direction of the magnetic force lines emitted by the magnetic substance, so that an acting force is generated to drive the second cylinder to advance, and the magnitude of the current is in direct proportion to the magnitude of the acting force. While the second cylinder moves forward, the elastic material between the annular flange and the magnetic material is squeezed due to the gradual approach of the annular flange and the magnetic material, and a reaction force is generated on the second cylinder. Therefore, the balance between the acting force and the reacting force can be adjusted by controlling the magnitude of the current, so that the positions of the second cylinder and the lens device positioned in the second cylinder can be determined. Therefore, as long as fine adjustment of the current magnitude can be performed with high precision, the positioning accuracy of the lens can be improved.

The lens driving structure of the present invention has a lens barrel covering the lens, and a conductor coil is fixed around the outer surface of the lens barrel and surrounded by a spring. A magnet is disposed opposite the conductive coil, and the magnetic force lines provided by the magnet are directed toward and cut through the conductive coil, and when current is applied to the conductive coil, a force is applied to the conductive coil, and the magnetic force lines drive the lens barrel to move. The intensity of the acting force and the position of the lens sleeve can be controlled by adjusting the current on the conductor coil.

In summary, the lens driving mechanism with a special structure of the present invention has the advantages of high positioning accuracy, easy control and small volume. The lens driving mechanism has the advantages and practical values, does not have similar structural design, is published or used, is innovative, has great improvement on the structure or function of the product, has great technical progress, produces good and practical effects, has multiple enhanced effects compared with the existing lens driving mechanism, is more suitable for practical use, has industrial wide utilization value, and is a novel, advanced and practical new design.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to implement them in accordance with the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.

Drawings

Fig. 1A is an exploded view of a lens driving mechanism according to an embodiment of the present invention.

Fig. 1B is a sectional view of a lens driving mechanism according to an embodiment of the present invention.

Fig. 2A is a schematic operation diagram of a lens driving mechanism according to an embodiment of the present invention.

Fig. 2B is a schematic diagram of the lens driving mechanism according to the embodiment of the present invention.

100: lens driving mechanism 102: lens sleeve

104: flange 106: groove

108: lens 110: conductor coil

112: spring 114: magnet

116: a magnetizer 118: mechanism sleeve

120: magnetic line 122: direction of rotation

202: a magnet 204: conductor coil

206: magnetic force line 208: direction of rotation

Detailed Description

To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description of the embodiments, structures, features and effects of the lens driving mechanism according to the present invention will be made with reference to the accompanying drawings and preferred embodiments.

The basic idea of the present invention is to control the position of the lens by the acting force generated by the interaction of the current and the magnetic force lines, so that the lens can be directly driven to perform linear reciprocating motion without an additional transmission mechanism, and high positioning accuracy can be achieved by a simple control method.

Fig. 1A is an exploded view of an embodiment of the present invention. Some of the main components of the lens driving mechanism 100 are seen in the figure, which includes the lens sleeve 102, the lens 108, the conductive coil 110, the spring 112, the two magnets 114, the magnetic conductor 116 between the two magnets 114, and the mechanism sleeve 118 that covers the entire driving mechanism.

The lens 108 is accommodated and fixed in the lens sleeve 102, and the conductive coil 110 is wound and fixed on the outer surface of the lens sleeve 102. In the present embodiment, the conductive coil 110 is fixed by the annular groove 106 surrounding the outer surface of the lens sleeve 102, i.e., the conductive coil 110 is surrounded in the annular groove 106. In addition, a flange 104 extends from the outer surface of the lens sleeve 102 perpendicular to the outer surface. When the spring 112 is looped around the lens barrel 102, the flange 104 of the lens barrel 102 and the spring 112 contact each other to support the spring 112 so that the lens barrel 102 does not penetrate the spring 112.

The mechanism sleeve 118 can encase all of the components described above, i.e., the lens sleeve 102 that encases the lens 108 on the inside and is wrapped around the conductor coil 110 and surrounded by the spring 112 on the outside. Two ring-shaped magnets 114 and a magnetic conductor 116 sandwiched between the two magnets 114 are fixed to the inner surface of a mechanism sleeve 118.

Fig. 1B is a sectional view of the lens driving mechanism 100 shown in fig. 1A after the elements are assembled, so that the relative positions of the elements can be more clearly seen. The lens sleeve 102 encloses the lens 108, the conductive coil 110 is wound in the annular groove 106 on the outer surface of the lens sleeve 102, the spring 112 surrounds the lens sleeve 102, one end of the spring 112 is connected to the flange 104 on the outer surface of the lens sleeve 102, and finally, the lens sleeve 102 is entirely enclosed by the mechanism sleeve 118 having two magnets 114 and a magnetic conductor 116 between the two magnets on the inner surface. The magnet 114 and the magnetic conductor 116 are located opposite to the conductive coil 110, that is, the magnetic lines of force emitted from the magnet 114 and the magnetic conductor must be able to cut through the conductive coil 110. In addition, when the lens barrel 102 moves the spring 112 to the right as viewed in the direction of fig. 1B, the magnet 114 must be positioned to contact the spring 112 to compress the spring 112 between the flange 104 and the magnet 114.

Fig. 2A is a schematic diagram showing the operation of a lens driving mechanism according to an embodiment of the present invention. In the lens position control method of the present invention, since the position of the mechanism sleeve 118 in the lens driving mechanism 100 is fixed, neither the mechanism sleeve 118 in fig. 1B nor fig. 2B is shown. First, it is seen that the surfaces of the two magnets 114 that are bonded to the magnetizer 116 are both N-poles, and the other surfaces that are not bonded to the magnetizer 116 are both S-poles. As can be seen from the characteristics of the magnetic material, the magnetic lines of force are emitted from the N pole to the S pole of the magnetic material, and therefore, some of the magnetic lines of force emitted from the magnet 114 in fig. 2A are guided by the magnetizer 116 and emitted to and cut through the magnetic lines of force 120 of the conductive coil 110.

According to Lorentz Law, if a current is applied to the conductive coil 110, a force F is generated on the conductive coil 110 in the direction 122, and the magnitude of the force F is:

F＝rIL×B

wherein,

i is the current intensity on the conductor coil 110;

l is the total length of the conductor coil 110;

b is the magnetic flux density; and

r is the ratio of the length of the conductor coil 110 in the magnetic field to its total length. As can be seen from the mechanism of the embodiment, the total length L of the conductor coil 110 is a fixed value, the magnetic flux density B of the magnetic flux lines 120 passing through the conductor coil 110 is also a fixed value generated by the magnet 114, and since the magnet 114 surrounds the conductor coil 110, the conductor coil 110 is entirely cut by the magnetic flux lines 120, so the ratio r can be regarded as 1. In this case, the magnitude of the force F is related to the intensity of the current I remaining in the conductive coil 110, and is proportional to the intensity of the current I, i.e. the greater the current flowing through the conductive coil 110, the stronger the force on the conductive coil in the direction 122.

Since the conductive coil 110 is fixed on the lens barrel 102, when the conductive coil 110 is driven by the force in the direction 122, the lens barrel 102 and the lens 108 fixed therein are also moved in the direction 122. As the lens barrel 102 moves in the direction 122, the spring 112 is compressed by the reduction in the position of the flange 104 relative to the magnet 114, thereby generating a reaction force on the lens barrel 102 in a direction opposite to the direction 122, which increases as the compression of the spring 112 increases, i.e., if a larger amount of movement is desired for the lens barrel 102, a stronger current must be applied to the conductive coil 110, and a larger force is generated in the direction 122 to resist the reaction force from the spring 112. When the force and the reaction force reach equilibrium, the lens sleeve 102 and the lens 108 stop at a fixed position. As can be understood from the above principle, the lens barrel 102 can be moved to a desired position by controlling the magnitude of the current flowing through the conductive coil 110. When the current flowing through the conductive coil 110 is stopped, the lens sleeve 102 returns to the initial position due to the reaction force of the spring 112.

In the embodiment shown in fig. 2A, two ring magnets 114 and a ring magnetizer 116 for increasing the magnetic flux density are utilized. Another embodiment of the invention implemented with only a ring magnet is provided in fig. 2B. The structure shown in fig. 2B is similar to the structure shown in fig. 2A, with only the magnet portion being modified to have only one ring magnet 202, wherein the surface of the magnet 202 opposite the conductive coil 204 has N poles and the surface opposite the conductive coil 204 has S poles. It can be seen that the magnetic field lines 206 emitted from the magnet 202 are also emitted toward the conductive coil 204 and cut through the conductive coil 204, so that a force is generated in the direction 208 when a current is applied to the conductive coil 204, and the principle and control method are the same as those of the embodiment shown in fig. 2A.

It should be noted that the magnets mentioned in the above description are intended to generally refer to any magnetic substance that can provide a fixed magnetic field, such as a general magnet or an electromagnet, and in the above embodiment, a neodymium iron boron (Nd-Fe-B) magnet having high residual magnetic flux density and coercive force characteristics is used. The magnetizer is generally any magnetic conductive material capable of converging magnetic lines into a uniform magnetic field with high magnetic flux density. The spring can be replaced by any elastic material with restoring force, such as a flat spring or a rubber block.

As is apparent from the above description of the lens driving mechanism, the lens can be moved to a desired position by applying a current of an appropriate magnitude to the conductor coil. Therefore, in a zoom camera device using the lens driving mechanism, the lens can be easily moved to achieve the purpose of zooming by only adding a zoom control circuit. The zoom control circuit can calculate and output a current of an appropriate magnitude according to actual conditions, and therefore can be implemented by using components such as a processor.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A lens driving mechanism characterized by comprising:

a lens barrel, wherein the inside of the lens barrel is enough to contain and fix a lens device and is provided with a flange which extends out from the outer surface of the lens barrel vertically;

a conductor coil surrounding and fixed on the outer surface of the lens sleeve;

an elastic device surrounding the lens sleeve;

a mechanism sleeve, wherein the mechanism sleeve is sufficiently internal to accommodate the lens sleeve and the elastic device; and

a magnetic device arranged on the inner surface of the mechanism sleeve and composed of at least one magnet set, wherein each magnet set is composed of a pair of magnets and a magnetic conductive material between the magnets, the surfaces of the magnets, which are jointed with the magnetic conductive body, have the same magnetism,

when the lens sleeve and the elastic device are arranged in the mechanism sleeve, the magnetic device is opposite to the conductor coil, so that when a current flows on the conductor coil, the conductor coil can generate an acting force to drive the lens sleeve to move, and when the lens sleeve moves, the flange and the magnetic device can simultaneously and respectively compress the elastic device from two ends of the elastic device, so that the elastic device generates a reaction force on the lens sleeve, the intensity of the acting force can be controlled by adjusting the intensity of the current, the balance between the flange and the reaction force is obtained, and the lens sleeve is moved to a required position.

2. The lens driving mechanism as claimed in claim 1, wherein the lens barrel has a groove around an outer surface thereof, and the conductor coil is fixed to the lens barrel in such a manner as to be wound in the groove.

3. A lens driving mechanism according to claim 1, wherein said elastic means is a spring.

4. A lens driving mechanism according to claim 1, wherein said resilient means is a leaf spring.

5. The lens driving mechanism as claimed in claim 1, wherein the pair of magnets are neodymium iron boron magnets.

6. The lens driving mechanism as claimed in claim 1, further comprising a zoom control circuit for controlling the magnitude of the current.

7. The lens driving mechanism as claimed in claim 6, wherein the zoom control circuit is a processor.