JP2007108533A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus equipped with an actuator superior in the assemblability and achieving sufficient driving force, even when it drives a plurality of lenses. <P>SOLUTION: Since a magnet 32 is attached to a lens barrel 22, a wiring for supplying power from the outside need not be connected to a movable part, and assemblability and durability are improved. Since a coil 33 is fixed on an assembly housing 20 side, it is easy to perform wiring. Since heat is less likely to be conducted to lenses L1 to L4 even when the wiring is soldered on a support plate 52a, the optical characteristics of the lenses are restrained from being spoiled. Furthermore, since the coil 33 is provided to the assembly housing 20 side, installation space is easily secured, and since the number of windings is increased, the driving force can be enhanced. The coil 33 is easily exposed to the outside air, whereby heat radiation of the coil 33 is enhanced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus suitable for use in an imaging apparatus using a solid-state imaging device such as a CCD image sensor or a CMOS image sensor.

  2. Description of the Related Art In recent years, an image pickup apparatus equipped with an autofocus mechanism (hereinafter referred to as an AF mechanism) is mounted along with improvement in performance of an image pickup apparatus using a charge coupled device (CCD) type or a complementary metal oxide semiconductor (CMOS) type solid-state image pickup device. Mobile phones are becoming popular. Here, since the mobile phone is sometimes carried in a clothes pocket or the like, it is required to be compact even if it has multiple functions. However, when a general motor or actuator is used to drive the photographing lens, there is a problem that a relatively large installation space is required.

On the other hand, in Patent Document 1, a U-shaped cylindrical yoke, a magnet attached to the inner surface of the outer wall of the yoke, a carrier having a lens at the center position, a coil attached to the carrier, and a yoke are attached. A lens driving device including a base, a frame that supports the base, and two springs that support the carrier is disclosed. By energizing the coil, the lens moves in the optical axis direction together with the carrier, so that a focusing operation can be performed.
JP 2004-280031 A

  Here, since the coil is mounted on the movable carrier, it becomes a problem how to energize from an external power source. That is, if power is simply supplied to the coil by wiring, the movement of the carrier may be hindered by the rigidity of the wiring itself. On the other hand, according to the technique of Patent Document 1, the problem of wiring is solved by supplying power via a spring, but this is not sufficient. In such a case, if you try to connect the wiring from an external power supply to the spring by soldering, the heat when melting the solder is transferred to the lens, but in the case of a plastic lens, its optical characteristics are significantly degraded by heat. There is a fear. In addition, since the lens is extremely light, imbalance may be caused by soldering, which may adversely affect the focusing operation. Furthermore, when driving a plurality of lenses, it is necessary to increase the driving force of the actuator, but it is difficult to increase the number of windings of the coil mounted on the carrier due to space and heat problems. I can say that.

  The present invention has been made in view of the problems of the prior art, and provides an imaging apparatus equipped with an actuator that is excellent in assemblability and can exhibit a sufficient driving force even when driving a plurality of lenses. For the purpose.

An imaging apparatus according to claim 1 is provided.
A housing,
A photographic lens including at least one movable lens movable in the optical axis direction with respect to the housing;
An elastic member that elastically supports the movable lens with respect to the housing;
And an actuator including a magnet coupled to the movable lens and a coil fixed to the housing.

  According to the present invention, since the magnet is coupled to the movable lens, it is not necessary to connect the wiring for supplying electric power from the outside to the movable part, and the assembling property and durability are improved. In addition, since the coil is fixed to the housing side, wiring can be easily performed, and even when the wiring is soldered, heat is not easily transmitted to the movable lens, so that the optical characteristics are not impaired. . Furthermore, since the coil is provided on the housing side, it is easy to secure an installation space, and thereby the number of windings can be increased, so that the driving force can be increased. In addition, heat dissipation is enhanced by making it easier to touch outside air.

  The imaging device according to a second aspect is the imaging device according to the first aspect, wherein the yoke and the magnet are disposed so as to surround the magnet except for a surface facing the coil. By increasing the magnetic flux density between them, a high driving force can be exhibited.

According to a second aspect of the present invention, in the invention of the first or second aspect, the actuator is cylindrical, and the most image-side lens on the most image side of the movable lens is larger than the inner diameter of the actuator. At least two of the movable lenses other than the most image side lens have an outer diameter, and are arranged on the inner side in the optical axis orthogonal direction of the inner diameter.

  According to the present invention, it is possible to provide an imaging apparatus equipped with an actuator that is excellent in assemblability and can exhibit a sufficient driving force even when driving a plurality of lenses.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a perspective view of an imaging apparatus 50 including the imaging apparatus according to the present embodiment, FIG. 2 is a top view of the imaging apparatus 50 of FIG. 1, and FIG. 3 shows the imaging apparatus 50 of FIG. It is the figure which cut | disconnected by the III-III line and looked at the arrow direction.

  The imaging apparatus 50 includes a CMOS image sensor 51 as a solid-state imaging device having a photoelectric conversion unit 51a, an imaging lens 10 as an imaging lens that causes the photoelectric conversion unit 51a of the image sensor 51 to capture a subject image, and an image sensor. IR cut filter F disposed between 51 and imaging lens 10, substrate 52 having external connection terminal 54 (FIG. 1) for holding image sensor 51 and transmitting and receiving electrical signals, and imaging lens An assembly housing 20 to be supported and an actuator (also referred to as a focus actuator) 30 for driving a focusing lens are provided, and these are integrally formed. The height Δ in the optical axis direction of the imaging apparatus 50 is 10 mm or less.

  In the image sensor 51, a photoelectric conversion unit 51a as a light receiving unit in which pixels (photoelectric conversion elements) are two-dimensionally arranged is formed in the center of a plane on the light receiving side. A processing circuit (not shown) is formed. Such a signal processing circuit includes a drive circuit unit that sequentially drives each pixel to obtain a signal charge, an A / D conversion unit that converts each signal charge into a digital signal, and a signal that forms an image signal output using the digital signal. It consists of a processing unit and the like. A number of pads (not shown) are arranged near the outer edge of the plane on the light receiving side of the image sensor 51, and are connected to the substrate 52 via wires W. The image sensor 51 converts the signal charge from the photoelectric conversion unit 51 a into an image signal such as a digital YUV signal, and outputs the image signal to a predetermined circuit on the substrate 52 via the wire W. Here, Y is a luminance signal, U (= R−Y) is a color difference signal between red and the luminance signal, and V (= BY) is a color difference signal between blue and the luminance signal. Note that the image sensor is not limited to the above CMOS image sensor, and other devices such as a CCD may be used.

  The substrate 52 includes a support flat plate 52a that supports the image sensor 51 and the outer cylinder 21 on one plane, and a flexible substrate 52b (FIG. 1) having one end connected to the support flat plate 52a.

  The support flat plate 52a has a large number of signal transmission pads provided on the surface thereof, which are connected to the wires W from the image sensor 51 described above and to the flexible substrate 52b.

  As described above, one end of the flexible substrate 52b is connected to the support flat plate 52a, and the support flat plate 52a and an external circuit (for example, a host device on which an imaging device is mounted) are connected via an external connection terminal 54 provided at the other end. Control circuit), and a voltage and a clock signal for driving the image sensor 51 are supplied from an external circuit, and a digital YUV signal can be output to the external circuit. Furthermore, the intermediate portion in the longitudinal direction of the flexible substrate 52b is flexible or easily deformable, and the deformation gives freedom to the orientation and arrangement of the external output terminals with respect to the support flat plate 52a.

  The assembly housing 20 made of a light-shielding member is disposed so as to surround the image sensor 51, and has a lower cylinder 21A in which the lower end is bonded to the support flat plate 52a using an adhesive B, and is coaxial with the lower cylinder 21A. The upper cylinder 21B sandwiches the coil 33 of the actuator 30 therebetween. As shown in FIG. 1, since the lower cylinder 21A is cylindrical and the support flat plate 52a is rectangular, a space is generated near the corners of the rectangle. Therefore, using this space, the lower cylinder 21A and the upper cylinder 21B are connected by a bridging portion 21C that extends parallel to the optical axis.

  In FIG. 3, an IR cut filter F is attached to a flange portion 21a extending radially inward from the inner periphery of the lower cylinder 21A.

  The movable cylinder 22 arranged to be movable with respect to the assembly housing 20 has a large cylindrical portion 22a, a small cylindrical portion 22b connected to the upper end thereof, and a flange portion 22c formed on the upper end thereof. The first lens l1, the second lens L2, the third lens L3, and the fourth lens L4 are held in a fixed manner in the order from the object side. A central opening of the flange portion 22c is an aperture stop S.

  Four cylindrical magnets 32 are arranged on the outer periphery of the small cylindrical portion 22b of the movable cylinder 22 in a cylindrical shape obtained by dividing an annular body whose upper and lower surfaces and inner peripheral surface are covered with a yoke 31 into four parts. The outer peripheral surface of the magnet 32 that is not covered by the yoke 31 faces the inner periphery of the cylindrical coil 33, but preferably has a smaller diameter than the outer peripheral surface of the large cylindrical portion 22a. A power supply wiring H for connecting the coil 33 and the support flat plate 52a is attached in close contact with the outer wall of the lower cylinder 21A. The yoke 31, the magnet 32, and the coil 33 constitute a cylindrical actuator 30.

  The spring member 27 having a shape in which donut discs having different diameters are connected to each other by shifting the phase of the connection position, the outer peripheral side thereof is fixed near the lower end of the lower cylinder 21A, and the inner peripheral side thereof is the flange portion of the fourth lens L4. It is fixed on the bottom surface. On the other hand, the spring member 28 having a shape similar to that of the spring member 27 (see FIG. 2) has an outer peripheral side fixed to the upper end of the upper cylinder 21 </ b> B and an inner peripheral side fixed to the upper end of the movable cylinder 22. The spring members 27 and 28, which are elastic members, generate a biasing force in accordance with the movement of the moving cylinder 22 in the optical axis direction together with the lenses 11 to L4.

  The imaging lens 10 has, in order from the object side, an aperture stop S, a first lens L1 having a positive refractive power and a convex surface facing the object side, a second lens L2 having a negative refractive power, and a positive refractive power. The third lens L3 and the fourth lens L4 having negative refractive power are included. The lenses L1, L2, L3, and L4 are positioned in the optical axis direction and the direction perpendicular to the optical axis by fitting the flange portions to each other, and are held by the movable cylinder 22 in a state where the optical axes coincide with each other. ing. In the present embodiment, the lenses L1, L2, L3, and L4 constitute a focusing lens (also referred to as a movable lens). However, since the outer diameters of the lenses L1 and L2 are smaller than those of the lenses L3 and L4, A thick magnet 32 can be incorporated into the movable cylinder 22 by utilizing the outer diameter difference. With this configuration, even if the most image side lens L4 (most image side lens) has an outer diameter larger than the inner diameter of the actuator (the interval between the opposing yokes 31), the two lenses (L1, L1) Since L2) can be arranged on the inner side in the direction perpendicular to the optical axis of the inner diameter of the actuator, the actuator can be arranged without enlarging the diameter in the direction perpendicular to the optical axis. The number of lenses arranged on the inner side of the actuator inner diameter in the direction perpendicular to the optical axis is not limited to two, but may be three including L3.

  The imaging lens 10 is used to form a subject image on a solid-state imaging device using the aperture stop S and the lenses L1, L2, L3, and L4 as an optical system. The aperture stop S is a member that determines the F number of the entire imaging lens system.

  The IR cut filter F held by the flange portion 21a of the outer cylinder 21 between the imaging lens 10 and the image sensor 51 is a member formed in, for example, a substantially rectangular shape or a circular shape.

  Further, a light shielding mask may be disposed between the third lens L3 and the fourth lens L4, so that unnecessary light is incident outside the effective diameter of the fourth lens L4 close to the solid-state imaging device. To prevent ghosts and flares.

  A usage mode of the imaging apparatus 50 described above will be described. FIG. 4 is a diagram illustrating a state in which the imaging device 50 is installed in a mobile phone 100 as a mobile terminal. FIG. 5 is a control block diagram of the mobile phone 100.

  In the imaging device 50, for example, the object-side end surface of the outer cylinder 21 in the imaging lens is provided on the back surface of the mobile phone 100 (the liquid crystal display unit side is the front surface), and is arranged at a position corresponding to the lower side of the liquid crystal display unit. Established.

  The external connection terminal 54 of the imaging device 50 is connected to the control unit 101 of the mobile phone 100 and outputs an image signal such as a luminance signal or a color difference signal to the control unit 101 side.

  On the other hand, as shown in FIG. 5, the mobile phone 100 controls each part in an integrated manner, and supports and inputs a control part (CPU) 101 that executes a program corresponding to each process, and a number and the like with keys. An input unit 60, a display unit 70 for displaying captured images and videos in addition to predetermined data, a wireless communication unit 80 for realizing various information communication with an external server, and a mobile phone 100 By a storage unit (ROM) 91 that stores necessary data such as system programs, various processing programs, and terminal IDs, and various processing programs and data executed by the control unit 101, or processing data, or the imaging device 50 And a temporary storage unit (RAM) 92 that is used as a work area for temporarily storing imaging data and the like.

  When the photographer holding the mobile phone 100 directs the optical axis of the imaging lens 10 of the imaging device 50 toward the subject, an image signal is captured by the image sensor 51. For example, by performing image plane AF processing or the like, The focus shift can be detected. Since the control unit 101 supplies power to the actuator 30 so as to drive the lenses L1 to L4 in a direction to eliminate the focus shift, power is supplied to the coil 33 from the external connection terminal 54 via the wiring H. Is done. At this time, the magnetic flux density is increased by the yoke 31 arranged around the magnet 32, and the electric power can be efficiently converted into a magnetic force. Since the generated magnetic force and the biasing force of the deformed spring members 27 and 28 are balanced, the lenses L1 to L4 can be moved and held together with the movable barrel 22 to the optimum focusing position. Autofocus operation can be realized. If the driving force of the actuator 30 disappears due to the interruption of the power supply, the movable cylinder 22 returns to the original position.

  According to the present embodiment, since the magnet 32 is attached to the movable cylinder 22, it is not necessary to connect the wiring for supplying electric power from the outside to the movable part, and the assembling property and durability are improved. Further, since the coil 33 is fixed to the assembly housing 20 side, wiring can be easily performed, and even when the wiring is soldered to the support flat plate 52a, heat is not easily transmitted to the lenses L1 to L4. Is prevented from being damaged. Furthermore, since the coil 33 is provided on the assembly housing 20 side, it is easy to secure an installation space, and thereby the number of windings can be increased, so that the driving force can be increased. Moreover, since the outer periphery of the coil 33 is exposed, its heat dissipation is improved by touching the outside air.

  When the photographer presses the button BT shown in FIG. 4 at a desired photo opportunity, the release is performed, and the image signal is taken into the imaging device 50. The image signal input from the imaging device 50 is stored in the storage unit 92 or displayed on the display unit 70 by the control system of the mobile phone 100, and further externally as video information via the wireless communication unit 80. Will be sent to.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. For example, the movable lens may be any one or more of the lenses L1 to L4, and the total number of lenses is not limited to four.

It is a perspective view of the imaging device 50 concerning this Embodiment. It is a top view of the imaging device 50 of FIG. It is the figure which cut | disconnected the imaging device 50 of FIG. 1 by the III-III line | wire, and looked at the arrow direction. It is a figure which shows the state equipped with the imaging device 50 in the mobile telephone 100 as a portable terminal. 3 is a control block diagram of the mobile phone 100. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Imaging lens 20 Assembly housing | casing 21 Outer cylinder 21A Lower cylinder 21B Upper cylinder 21C Bridge part 21a Flange part 22 Moving cylinder 22a Large cylindrical part 22b Small cylindrical part 22c Flange part 27 Spring member 28 Spring member 30 Actuator 31 Yoke 32 Magnet 33 Coil DESCRIPTION OF SYMBOLS 50 Image pick-up device 51 Image sensor 51a Photoelectric conversion part 52 Board | substrate 52a Support flat plate 52b Flexible board 54 External connection terminal 60 Input part 70 Display part 80 Wireless communication part 92 Memory | storage part 100 Mobile phone 101 Control part B Adhesive BT Button F Cut filter L1-L4 Lens S Aperture stop W Wire

Claims (3)

A housing,
A photographic lens including at least one movable lens movable in the optical axis direction with respect to the housing;
An elastic member that elastically supports the movable lens with respect to the housing;
An image pickup apparatus comprising: a magnet coupled to the movable lens; and an actuator including a coil fixed to the housing.   The imaging apparatus according to claim 1, wherein a yoke is disposed so as to surround the periphery of the magnet except for a surface facing the coil. The actuator is cylindrical, and the most image side most image side lens in the movable lens has an outer diameter larger than the inner diameter of the actuator, and at least two of the movable lenses other than the most image side lens. The imaging device according to claim 1, wherein the two lenses are arranged on the inner side of the inner diameter in the direction perpendicular to the optical axis.

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