JP2008249765A - Imaging apparatus and mobile terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus which is formed into a quadrangle, when viewed from an object side, so that even when a driving means is arranged around an imaging lens, predetermined performance can be demonstrated. <P>SOLUTION: In the imaging apparatus provided with: the imaging lens which allows an image sensor to form the optical image of an object; a lens barrel which holds the imaging lens; the driving means which drives the lens barrel; and a housing which stores at least the imaging lens, the lens barrel and the driving means and is formed into an almost quadrangle when viewed from the object side, the imaging lens is formed into such a shape that a part of a circular arc is cut when viewed from the object side and the driving means is arranged in a gap formed by the cut part and the housing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a small imaging device and a portable terminal including the imaging device.

  2. Description of the Related Art In recent years, an imaging device mounted on a mobile terminal such as a mobile phone or a PDA (Personal Digital Assistant) is particularly required to be downsized. The imaging apparatus includes an imaging lens, a lens barrel that holds the imaging lens, a driving unit that drives the lens barrel, an imaging element, and a circuit board that performs image processing on an image signal photoelectrically converted by the imaging element.

  In the imaging apparatus, the circuit board can be arranged at a desired position and can be divided as appropriate, so that miniaturization is not hindered. Further, an image sensor such as a CCD (Charge Coupled Device) type image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor is not so large, and thus does not hinder downsizing. However, the outer diameter of the image pickup lens is larger than that of other members, and if the driving means is arranged around the image pickup lens, the outer diameter of the image pickup apparatus is increased, which hinders downsizing.

  On the other hand, in order to provide various types of models with different functions and performance at a low price, there are cases where the basic shape is made common. In such a case, for example, even if the number of pixels of the imaging device is different and the function / performance is different, an imaging device having a common external dimension is required. In recent years, an imaging device having a rectangular parallelepiped shape has been frequently used in order to reliably incorporate the imaging device in a limited gap of the mobile terminal. Furthermore, there is an imaging apparatus formed so as to be in a positive direction when viewed from the subject side so that the orientation of the imaging apparatus can be changed depending on the model of the mobile terminal.

  With respect to such an imaging apparatus, higher optical performance is required due to the adoption of a zoom lens and the like, and accordingly, driving means for zooming driving and focusing driving have been required.

  Therefore, there is an imaging device formed in a quadrangle when viewed from the subject side, in which an imaging lens is arranged at the center and a driving unit is arranged around the imaging lens, which is disclosed in a patent gazette (for example, see Patent Document 1). .

In Patent Document 1, since the four corners of the imaging device are formed at the corners, and the driving means is a motor and is circular when viewed from the subject side, dead spaces are generated at the four corners. Therefore, the dead space is eliminated by placing support posts at the four corners.
JP 11-305104 A

  In the imaging device formed in a quadrangle when viewed from the object side, if the driving means is arranged directly around the imaging lens as in Patent Document 1, the outer diameter of the imaging device becomes large.

  In order to prevent the image pickup apparatus from becoming large, either the image pickup lens or the driving unit is formed small. However, if the imaging lens is formed small, it affects the optical performance such that a bright lens or a wide-angle lens cannot be mounted. On the other hand, when the driving means is formed small, the driving force is weakened, and there arises a problem that the movable imaging lens is limited or the moving speed of the imaging lens becomes slow.

  The present invention has been made in view of such a problem, and in an imaging device formed in a quadrangle when viewed from the subject side, even if a driving unit is disposed around the imaging lens, neither the imaging lens nor the driving unit is reduced. An object of the present invention is to propose an imaging device capable of exhibiting predetermined performance and a portable terminal equipped with the imaging device.

The object is achieved by the invention described below.
1. An imaging lens that forms an optical image of a subject on an imaging device;
A lens barrel holding the imaging lens;
Driving means for driving the lens barrel;
A housing that stores at least the imaging lens, the lens barrel, and the driving unit, and is formed in a substantially rectangular shape when viewed from the subject side;
In an imaging apparatus comprising:
The imaging lens is formed in a shape in which a part of an arc is notched when viewed from the object side, and the driving means is disposed in a gap formed by the notched portion and the housing. .
2. 2. The imaging apparatus according to 1, wherein the imaging lens is formed in a substantially rectangular shape when viewed from the subject side.
3. The imaging apparatus according to 1 or 2, wherein the lens barrel is formed to have substantially the same thickness according to the shape of the imaging lens when viewed from the subject side.
4). 4. The device according to claim 1, wherein the housing is formed in a substantially square shape when viewed from the subject side, and the optical axis of the imaging lens and the center of the housing are substantially matched. Imaging device.
5. The imaging apparatus according to any one of claims 1 to 4, wherein the driving means includes a piezoelectric element.
6). The imaging apparatus according to any one of claims 1 to 4, wherein the driving means includes a voice coil motor.
7). The imaging apparatus according to any one of claims 1 to 4, wherein the driving unit includes a stepping motor.
A mobile terminal comprising the imaging device according to any one of 8.1 to 7.

  According to the imaging device of the present invention and the portable terminal including the imaging device, the imaging lens and the driving unit can be made small even if the imaging unit is formed in a square shape when viewed from the subject side and the driving unit is arranged around the imaging lens. And a predetermined performance can be exhibited.

  Embodiments of an imaging apparatus and a mobile terminal according to the present invention will be described in detail with reference to the drawings.

  First, an example of a mobile phone as a mobile terminal equipped with an imaging device will be described with reference to the external view of FIG. 1A is a view of the folded mobile phone when viewed from the inside, and FIG. 1B is a view of the folded mobile phone when viewed from the outside.

  In FIG. 1, in the mobile phone T, an upper casing 71 as a case having display screens D <b> 1 and D <b> 2 and a lower casing 72 having an operation button B are connected via a hinge 73. The imaging device is built under the display screen D <b> 2 in the upper casing 71, and the imaging lens L is exposed on the outer surface of the upper casing 71.

  Note that the position of the imaging device may be disposed above or on the side of the display screen D2 in the upper casing 71. Further, the mobile phone T is not limited to a folding type.

  Next, an example of an embodiment of an imaging device will be described with reference to FIGS. 2 is a cross-sectional view of the imaging apparatus, FIG. 3 is a front view of the imaging apparatus, and FIG. 4 is a diagram for explaining the driving principle of the driving means.

  First, each member is demonstrated based on FIG.2 and FIG.3.

  L1 is an imaging lens, which may be a single focus lens or a zoom lens.

  Reference numeral 1 denotes an image sensor, which is a CCD or a CMOS. Then, the subject light forms an image on the image sensor 1 by the imaging lens L1.

  Reference numeral 21 denotes a lens barrel, which holds the imaging lens L1.

  Reference numeral 31 denotes a casing which stores each member of the imaging apparatus and is formed in a rectangular parallelepiped.

  Reference numeral 4 denotes a driving means, which uses an electrical conversion element such as a piezoelectric element (piezo element) that expands and contracts when a voltage is applied, and is called SIDM (Smooth Impact Drive Mechanism).

  The drive unit 4 includes an electric conversion element 41, a vibration member 42, a holding member 43, and a leaf spring 44.

  The electrical conversion element 41 is a piezoelectric element in which a large number of piezoelectric plates are stacked, and expands and contracts when a voltage is applied.

  The vibration member 42 is a rod-shaped member coupled to one end of the electric conversion element 41 in the expansion / contraction direction, and is formed of a hard material having good slipperiness. And it arrange | positions in parallel with the optical axis O of the imaging lens L1.

  The holding member 43 cantileverly holds the other end of the electric conversion element 1 in the expansion / contraction direction and is formed of a metal material having a mass.

  The leaf spring 44 presses the vibrating member 42 and the lens barrel 21 and engages them with a predetermined frictional force.

  The driving unit 4 is driven according to the principle described later, and the lens barrel 21 is moved in the direction of the optical axis O along the vibration member 42. Therefore, the imaging lens L1 is also moved in the direction of the optical axis O.

  Reference numeral 5 denotes a guide shaft, which is disposed in parallel with the optical axis O and prevents the lens barrel 21 from rotating about the vibration member 42.

  Here, the driving principle of the driving means 4 will be described with reference to FIG.

  During driving, a pulse voltage having a sawtooth waveform is continuously applied to the electrical conversion element 41 via a flexible printed board (not shown). As a result, the electric conversion element 41 expands and contracts and the vibration member 42 also vibrates in the axial direction. The electrical conversion element 41 expands relatively slowly at the gradual rise a of the pulse voltage. Therefore, the vibration member 42 moves in a direction away from the holding member 43 (A direction), and accordingly, the lens barrel 21 also moves in the same direction. On the other hand, at the rapid fall b of the pulse voltage, the electrical conversion element 41 rapidly contracts and returns to the initial length. At this time, the vibration member 42 also rapidly moves in the direction toward the holding member 43 (B direction), but the lens barrel 21 remains in that position due to inertia or slightly moves in the direction of the holding member 43. Therefore, by continuously applying such a pulse voltage, the lens barrel 21 is gradually moved in the A direction according to the number of pulses.

  When the lens barrel 21 is moved in the B direction, the pulse voltage of the sawtooth waveform applied to the electrical conversion element 1 may be reversed so as to make a rapid rise and a gentle fall.

  As described above, the focusing operation and the zooming operation can be performed by moving the lens barrel 21.

  In addition, SIDM is suitable for small devices such as an imaging device because it has high accuracy and high responsiveness and operates quietly.

  The driving means for driving the lens barrel 21 is not limited to the above SIDM, and a voice coil motor or a stepping motor may be used.

  Next, means for achieving downsizing in the imaging apparatus configured as described above will be described below.

  As shown in FIG. 3, the imaging lens L1 is formed in a circular shape when viewed from the subject side. However, since the imaging screen of the imaging device 1 is rectangular, the necessary lens shape is within the rectangular range drawn by the two-dot chain line, and the outer portion does not contribute at all for imaging.

  Accordingly, a circular arc imaging lens L2 as shown in FIG. 5 is formed by cutting out an arc portion that does not contribute to imaging in the imaging lens L1 when viewed from the subject side. As a result, the vertical and horizontal dimensions of the imaging lens L2 are significantly shortened compared to the imaging lens L1.

  Therefore, if the lens barrel 22 that holds the imaging lens L2 is formed to have a substantially equal thickness, the driving means 4 and the guide shaft 5 can be moved in the direction of the optical axis O and arranged. In other words, the driving means 4 can be arranged in the gap formed by the notched portion of the imaging lens L1 and the housing 31. Along with this, the outer diameter of the casing 31 can be shortened to make the casing 32 smaller.

  Note that the imaging lens L2 in FIG. 5 has a shape in which four upper, lower, left, and right arcs of the imaging lens L1 are cut out, but depending on the case, a part of the imaging lens L1, that is, one to three arcs. A cut-out shape may be used.

  In addition, according to the increase in the number of mobile terminals, the housing is formed in a substantially square shape when viewed from the front so that the camera can be mounted on the mobile terminal even when the image pickup apparatus is rotated 90 degrees and the posture is changed. You may comprise an imaging device so that an optical axis and the center of a housing | casing may correspond substantially. The housing 33 in this state is shown by a two-dot chain line in FIG.

It is an external view of the mobile telephone as a portable terminal provided with the imaging device. It is sectional drawing of an imaging device. It is a front view of an imaging device. It is a figure explaining the drive principle of a drive means. It is a front view of the imaging device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image pick-up element 21,22 Lens barrel 31,32,33 Case 4 Drive means T Mobile telephone L, L1, L2 Imaging lens O Optical axis

Claims (8)

An imaging lens that forms an optical image of a subject on an imaging device;
A lens barrel holding the imaging lens;
Driving means for driving the lens barrel;
A housing that stores at least the imaging lens, the lens barrel, and the driving unit, and is formed in a substantially rectangular shape when viewed from the subject side;
In an imaging apparatus comprising:
The imaging lens is formed in a shape in which a part of an arc is notched when viewed from the object side, and the driving means is disposed in a gap formed by the notched portion and the housing. . The imaging apparatus according to claim 1, wherein the imaging lens is formed in a substantially rectangular shape when viewed from a subject side. The imaging apparatus according to claim 1, wherein the lens barrel is formed to have substantially the same thickness according to the shape of the imaging lens when viewed from the subject side. 4. The device according to claim 1, wherein the housing is formed in a substantially square shape when viewed from the subject side, and an optical axis of the imaging lens is substantially coincident with a center of the housing. The imaging device described in 1. The imaging apparatus according to claim 1, wherein the driving unit includes a piezoelectric element. The imaging apparatus according to claim 1, wherein the driving unit includes a voice coil motor. The imaging apparatus according to claim 1, wherein the driving unit includes a stepping motor. A portable terminal comprising the imaging device according to claim 1.

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