JP2007121850A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus which has compact constitution and on which an actuator capable of achieving full driving force is mounted. <P>SOLUTION: A fourth lens L4 having the largest outside diameter in an imaging lens is cut in parallel so that the dimension in a short side direction of effective luminous flux EL passing through the fourth lens L4 may be smaller than that in a long side direction, whereby the actuator 30 is arranged in space between an outer peripheral surface in the short side direction of the fourth lens L4 and an assembly housing 20. Thus, the degree of freedom in mounting the actuator 30 is improved, and the effective use of the space is achieved, thereby making the imaging apparatus 50 compact. <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.

Patent Document 1 discloses a lens driving device that can be used in such an imaging apparatus, and that can be used to drive the lens in the optical axis direction by arranging an actuator around the lens.
JP 2004-280031 A

  Incidentally, the lens driving device described in Patent Document 1 has a problem that the outer shape of the device becomes large because an actuator is provided around the lens. More specifically, it includes a circular lens configured to be larger than the outer edge of the effective light beam incident on the light receiving surface of the solid-state imaging device, and an actuator including a coil, a magnet, and a yoke that surrounds the lens. The body size was decided and it was difficult to make it compact. On the other hand, since the light-receiving surface of the solid-state imaging device is generally rectangular, there is a situation that the outer space in the short side direction has a relatively large margin.

  The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide an imaging apparatus equipped with an actuator that has a compact configuration and can exhibit a sufficient driving force.

An imaging apparatus according to claim 1 is provided.
A housing,
An imaging lens including at least one movable lens movable in the optical axis direction with respect to the housing;
A solid-state imaging device having a light receiving surface;
An actuator for driving the movable lens in the optical axis direction,
As for the external shape of at least one lens of the imaging lens, the dimension corresponding to the short side direction of the effective light beam passing therethrough is smaller than the dimension corresponding to the long side direction,
The actuator is arranged between the outer peripheral surface in the short side direction of the at least one lens and the housing.

  According to the present invention, the outer shape of at least one lens of the imaging lens is such that the dimension corresponding to the short side direction of the effective light beam passing therethrough is smaller than the dimension corresponding to the long side direction, Since the actuator is disposed between the outer peripheral surface in the short side direction of the two lenses and the housing, the degree of freedom of mounting the actuator is increased, and the space is effectively used, so that the compactness of the imaging device can be achieved. Can be achieved.

  According to a second aspect of the present invention, in the invention of the first aspect, the actuator coil is wound around an axis orthogonal to the optical axis. The outer shape of the image pickup apparatus can be made smaller than when wound around.

  The imaging device according to claim 3 is used for driving the movable lens between the outer peripheral surface in the short side direction of the at least one lens and the housing in the invention according to claim 1 or 2. Since the electronic component is arranged, the degree of freedom of mounting the electronic component is increased. The electronic components used for driving the movable lens include, but are not limited to, the actuator drive circuit and the movable lens position detection sensor.

  ADVANTAGE OF THE INVENTION According to this invention, the imaging device which has an actuator which has a compact structure and can exhibit sufficient driving force can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an image pickup apparatus 50 including the image pickup apparatus according to the present embodiment. FIG. 2 is a cross-sectional view of the image pickup apparatus 50 shown in FIG. FIG. FIG. 3 is a diagram of the imaging device 50 of FIG. 1 cut along a plane including the III-III line and viewed in the direction of the arrow.

  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.

  An assembly housing 20 made of a light-shielding member is disposed so as to surround the image sensor 51, and is attached to a lower cylinder 21A in which a lower end is bonded to the substrate 52 using an adhesive B and an upper part of the lower cylinder 21A. The short cylinder-shaped upper cylinder 21B and the square cylinder-shaped outer cylinder 21 including the lid member 21C are included.

  In FIG. 2, an IR cut filter F is attached to a flange portion 21a extending from the inner periphery of the lower cylinder 21A in the direction perpendicular to the optical axis. A stopper SP that contacts the moving cylinder 22 is disposed on the upper surface of the flange portion 21a.

  The movable cylinder 22 disposed so as to be movable with respect to the assembly housing 20 includes a cylindrical portion 22a, a small flange portion 22b formed at the upper end thereof, and a large flange portion extending in the radial direction from the lower end of the cylindrical portion 22a. 22c and a pair of driven surfaces 22f (see FIG. 3) parallel to the optical axis, and in the order of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 from the object side. These are fixedly held inside. A central opening of the small flange portion 22c is an aperture stop S. A lower portion of the cylindrical portion 22a is a D-cut portion 22d.

  The flange portion L1f of the first lens L1 is abutted and fitted so as to include the upper portion of the flange portion L2f of the second lens L2. Further, the flange portion L3f of the third lens L3 is abutted and fitted so as to contain the lower portion of the flange portion L2f of the second lens L2. The outer diameters of the first lens L1 and the second lens L2 are slightly smaller than the outer diameter of the third lens L3. Therefore, when the lenses L1 to L3 are assembled in the small cylindrical portion 22b so that the first lens L1 is abutted against the small flange portion 22b, the optical axis of the lens with respect to the moving cylinder 22 is the inner peripheral surface of the cylindrical portion 22a. And the outer diameter of the third lens L3 are accurately positioned, and the optical axes of the third lens L3 and the optical axes of the first lens L1 and the second lens L2 are obtained by fitting the flange portions. It will be positioned with high accuracy.

  On the other hand, the fourth lens L4, which is the most image side lens, is attached to the D-cut portion 22d of the cylindrical portion 22a, and a subject side end surface of the flange portion L4f is abutted against the step portion 22f of the movable barrel 22. In the present embodiment, the first lens L1 to the third lens L3 have a rotationally symmetric section around the optical axis, while the fourth lens L4 has a rotationally asymmetric section about the optical axis.

  4A is a view of the fourth lens L4 as viewed from the subject side, and FIG. 4B is a cross-sectional view of the fourth lens L4 of FIG. 4A taken along the line IVB-IVB in the direction of the arrow. FIG. The fourth lens L4 has a substantially circular optical surface L4s around the optical axis on the subject side surface, and a flange portion L4f around the optical surface L4s. Here, as indicated by a dotted line in FIG. 4A, the effective light beam EL received by the rectangular photoelectric conversion unit (also referred to as a light receiving surface) 51a of the image sensor 51 is incident on the optical surface L4s. Since the optical image formed on the portion other than the photoelectric conversion unit 51a becomes unnecessary light, the effective light beam EL has a substantially rectangular shape having a short side and a long side in the cross section in the direction perpendicular to the optical axis. Therefore, the vicinity of the outer periphery of the fourth lens L4 in the short side direction of the effective light beam EL (corresponding to the short side direction of the photoelectric conversion unit 51a) is an area that is not used for imaging. In the lens L4, both sides in the short side direction of the effective light beam EL are cut in parallel to form a D cut portion L4d. The outer shape of the fourth lens L4 corresponds to the D-cut portion 22d of the movable barrel 22.

  As shown in FIG. 3, the coils 33 are wound around the driven surface 22f of the movable barrel 22 extending in parallel with the D-cut portion L4d of the fourth lens L4, respectively, around the axis perpendicular to the optical axis. It is attached in a state. On the other hand, the magnet 32 is disposed so as to be opposed to the coil 33 and sandwiched between the upper tube 21b and the cover member 21C. A yoke 31 is disposed around each magnet 32. An actuator 30 is constituted by the coil 33, the magnet 32, and the yoke 31.

  In addition, on one side (the right side in FIG. 3) where the D-cut portion L4d of the fourth lens L4 is not formed, a hall element magnet Mg is attached to the movable cylinder 22 and faces the assembly casing 20 on the opposite side. Are provided with a Hall element HE that detects a position by detecting the magnetic force of the Hall element magnet Mg, and a flexible printed circuit board FPC that connects the Hall element HE and the substrate 52. On the other side (left side in FIG. 3) where the D-cut portion L4d of the fourth lens L4 is not formed, a drive circuit DR of the actuator 30 and a drive circuit DR are provided on the inner peripheral surface of the assembly housing 20. A flexible printed circuit board FPC that connects the substrate 52 is provided.

  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 is fixed to the upper cylinder portion 21B on the outer peripheral side and fixed to the lower surface of the movable cylinder 22 on the inner peripheral side. Yes. On the other hand, the spring member 28 having a shape similar to the spring member 27 has its outer peripheral side fixed to the upper surface of the cover member 21 </ b> C and its inner peripheral side fixed to the upper end of the movable cylinder 22. The spring members 27 and 28 generate an urging force in response to the movement cylinder 22 moving in the optical axis direction.

  A plus terminal of the coil 33 of the actuator 30 is connected to the spring member 27. Further, the spring member 27 is connected to the substrate 52 via a wiring H + that passes through the outer wall of the upper cylinder 21B and extends through the outer wall of the lower cylinder 21A. The negative terminal of the coil 33 is connected to the spring member 28. The spring member 28 is connected to the substrate 52 via the wiring H−. The coil 33 can be displaced with respect to the magnet 32 according to the supplied electric power by a magnetic force generated by supplying electric power to the coil 33 from the outside via the spring members 27 and 28 and the wirings H + and H−. it can.

  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. In the present embodiment, the lenses L1, L2, L3, and L4 constitute a focusing lens (also referred to as a movable lens).

  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 first lens L1 and the second lens L2 and between the second lens L2 and the third lens L3, thereby enabling effective diameters of the lenses L3 and L4 close to the solid-state imaging device. It is possible to prevent unnecessary light from being incident on the outer side of the glass and to suppress the occurrence of ghosts and flares.

  According to the present embodiment, the fourth lens L4 having the largest outer diameter among the imaging lenses is parallel so that the dimension in the short side direction of the effective light beam EL passing therethrough is smaller than the dimension in the long side direction. Therefore, the actuator 30 can be disposed in the space between the outer peripheral surface in the short side direction of the fourth lens L4 and the assembly housing 20, thereby providing a degree of freedom for mounting the actuator 30. The imaging device 50 can be made compact by increasing the space and effectively using the space.

  A usage mode of the imaging apparatus 50 described above will be described. FIG. 5 is a diagram illustrating a state in which the imaging device 50 is installed in a mobile phone 100 as a mobile terminal. FIG. 6 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. 6, the mobile phone 100 controls each unit in an integrated manner, and supports and inputs a control unit (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, the control unit 101 supplies the coil 33 from the external connection terminal 54 via the wirings H + and H−. Power is supplied. 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.

  When the photographer presses the button BT shown in FIG. 5 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 transmitted to the control system of the mobile phone 100 and stored in the storage unit 92 or displayed on the display unit 70, and further, video information is transmitted via the wireless communication unit 80. Will be transmitted to the outside.

  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, as in the above-described embodiment, two actuators 30 are not provided across the optical axis, but only one is provided, and the other is provided with a guide shaft that guides the movable cylinder 22, and the remaining space is used to A Hall element magnet Mg, a Hall element HE, a drive circuit DR, a flexible printed circuit board FPC, and the like may be provided between the outer peripheral surface in the short side direction of the four lenses L4 and the assembly housing 20. Further, 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 the figure which cut | disconnected the imaging device 50 of FIG. 1 by the surface containing an II-II line | wire, and looked at the arrow direction. It is the figure which cut | disconnected the imaging device 50 of FIG. 1 by the surface containing a III-III line | wire, and looked at the arrow direction. 4A is a view of the fourth lens L4 as viewed from the subject side, and FIG. 4B is a cross-sectional view of the fourth lens L4 of FIG. 4A taken along the line IVB-IVB in the direction of the arrow. FIG. 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 Assembling case 21 Outer cylinder 21A Lower cylinder 21B Upper cylinder 21a Flange part 21b Recessed part 22 Moving cylinder 22a Cylindrical part 22b Small flange part 22c Large flange part 22f Driven surface 27 Spring member 28 Spring member 30 Actuator 31 Yoke 32 Magnet 33 Coil 50 Imaging device 51 Image sensor 51a Photoelectric conversion unit 52 Substrate 54 External connection terminal 60 Input unit 70 Display unit 80 Wireless communication unit 92 Storage unit 100 Mobile phone 101 Control unit B Adhesive BT Button F Cut filters H +, H -Wiring L1-L4 Lens S Aperture stop W Wire

Claims (3)

A housing,
An imaging lens including at least one movable lens movable in the optical axis direction with respect to the housing;
A solid-state imaging device having a light receiving surface;
An actuator for driving the movable lens in the optical axis direction,
As for the external shape of at least one lens of the imaging lens, the dimension corresponding to the short side direction of the effective light beam passing therethrough is smaller than the dimension corresponding to the long side direction,
An imaging apparatus, wherein the actuator is disposed between an outer peripheral surface in a short side direction of the at least one lens and the housing.   The imaging apparatus according to claim 1, wherein the coil of the actuator is wound around an axis orthogonal to the optical axis. The imaging apparatus according to claim 1, wherein an electronic component used for driving the movable lens is disposed between an outer peripheral surface in a short side direction of the at least one lens and the housing.

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