JP2002372732A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make optimum swing and tilt regulation possible in correspondence to a lens movement position at every movement of a lens. SOLUTION: The imaging device having an imaging optical system A for picking up an image by moving the lens and an imaging element B for converting the optical image by the imaging optical system A to an electric signal has swing and tilt regulating means C which regulates the angle formed by the imaging plane and optical axis of the imaging element B according to the lens movement, memory means D which previously stores the swing and tilt regulation value in the lens movement position and control means E which controls the angle formed by the imaging plane and optical axis of the imaging element B by driving the swing and tilt regulating means in accordance with the swing and tilt regulation value previously stored in the memory means D according to the lens movement position of in photographing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus which can be used for, for example, a video camera and a digital camera.

[0002]

2. Description of the Related Art An imaging device for converting an optical image obtained from an imaging optical system into an electric signal has a high resolution and a small size in an imaging apparatus which can be used in a video camera, a digital camera and the like. Also, high accuracy is required for the degree of orthogonality of the image sensor with respect to the optical axis.

If the optical axis of the image pickup optical system changes, or the image pickup surface of the image pickup device is tilted, and the optical axis and the image pickup surface of the image pickup device are not perpendicular to each other, one-sided blurring or peripheral blurring occurs in the image. For this reason, for example, Japanese Utility Model Laid-Open No. 64-52
In some cases, as in Japanese Patent No. 254, when the image sensor is mounted, a tilt adjustment is performed so that the optical axis and the image plane of the image sensor are orthogonal.

[0004]

By the way, in a configuration in which the image pickup apparatus has an image pickup optical system for moving the lens and picking up an image, and the lens is moved for zooming and focusing, the tilt adjustment is made depending on the lens movement position. The optimal value may be different.

In this case, a fixed tilt adjustment value cannot be used. For example, in a configuration as disclosed in Japanese Patent Application Laid-Open No. 4-166920, it is possible to make the tilt adjustment value variable, but this is a correction for a subject tilted with respect to the optical axis. In the system, since the optimum value of the tilt adjustment is different each time, it is inevitable that one-sided blur or peripheral blur occurs in the image.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an image pickup apparatus capable of optimally adjusting a tilt in accordance with a lens movement position each time a lens is moved.

[0007]

Means for Solving the Problems In order to solve the above problems and achieve the object, the present invention has the following constitution.

According to a first aspect of the present invention, there is provided an image pickup apparatus having an image pickup optical system for moving a lens to pick up an image and an image pickup device for converting an optical image by the image pickup optical system into an electric signal. A tilt adjusting means for adjusting the angle between the imaging surface of the image sensor and the optical axis, a storage means for storing the tilt adjustment value at the lens moving position in advance, and the An imaging apparatus comprising: a control unit that drives the tilt adjustment unit based on a tilt adjustment value stored in advance in a storage unit and adjusts an angle between an imaging surface of the imaging element and an optical axis. ].

According to the first aspect of the present invention, the angle between the imaging surface of the imaging device and the optical axis is adjusted according to the movement of the lens, and the tilt adjustment value at the lens movement position is stored in advance. In response to the lens movement position at the time of shooting, the tilt adjustment means is driven based on the tilt adjustment value stored in the storage means in advance, and the tilt adjustment value is changed in accordance with the movement of the lens to change the lens movement position each time the lens moves. By performing the optimal tilt adjustment correspondingly, an image with less one-sided blur and peripheral blur can be obtained.

According to a second aspect of the present invention, there is provided an image forming apparatus, wherein the image pickup optical system is capable of performing zooming and focusing, and stores the tilt adjustment values at the zooming position and the focusing position in advance. 2. The imaging device according to 1. ].

According to the second aspect of the present invention, the adjustment values at the zooming position and the focusing position are stored in advance, so that the tilt adjustment values stored in advance corresponding to the zooming and focusing at the time of photographing are stored. The optimal tilt adjustment can be performed by driving the tilt adjusting means based on the above.

According to a third aspect of the present invention, there is provided an image forming apparatus, wherein the tilt adjusting means adjusts an angle between the imaging surface and the optical axis by changing a tilt of an imaging surface of the imaging device. The imaging device according to claim 1. ].

According to the third aspect of the present invention, the tilt of the image pickup surface of the image pickup device can be varied to adjust the angle between the image pickup surface and the optical axis, thereby making it possible to perform optimal tilt adjustment.

According to a fourth aspect of the present invention, there is provided a method according to the first aspect, wherein the tilt adjustment means is an independently displaceable piezoelectric element disposed on a light incident surface side or a rear side of the image pickup device. 4. The imaging device according to 3. ].

According to the fourth aspect of the present invention, the image pickup device can be moved to the optimum tilt position with a simple configuration using the independently displaceable piezoelectric element disposed on the light beam incident surface side or the rear side of the image pickup device. It is possible to

According to a fifth aspect of the present invention, there is provided an image forming apparatus, wherein the tilt adjusting means adjusts an angle between an imaging surface and an optical axis by changing an optical axis angle of the imaging optical system. The imaging device according to claim 1. ].

According to the fifth aspect of the present invention, it is possible to adjust the angle between the imaging surface and the optical axis by changing the optical axis angle of the imaging optical system, and to perform the optimum tilt adjustment.

According to a sixth aspect of the present invention, the tilt adjusting means is a wedge-shaped prism disposed in front of the image pickup device or in an image pickup optical system and capable of changing an optical axis angle. Item 6. The imaging device according to Item 5. ].

According to the sixth aspect of the present invention, it is possible to perform an optimum tilt adjustment with a simple configuration using a wedge-shaped prism capable of changing the optical axis angle.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the image pickup apparatus of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to this embodiment.

FIG. 1 is a block diagram of an image pickup apparatus applied to a digital camera, FIG. 2 is a configuration diagram of a tilt adjustment unit, and FIG. 3 is a diagram showing an arrangement of piezoelectric elements.

The digital camera 1 according to this embodiment has an imaging optical system A for moving a lens and imaging, and an imaging optical system A
An image sensor B that converts an optical image of the image sensor into an electric signal, and a tilt adjusting unit C that adjusts an angle between an image plane of the image sensor B and an optical axis.

The imaging optical system A includes zoom lenses 10 and 1
The zoom lenses 10, 11, and 12 are zoomed by being driven by a zoom motor M1, and the focus lens 13 is focused by being driven by a focus motor M2. The zoom position by the zooming is detected by the zoom encoder 14, and the zoom position information is sent to the sub CPU 20. The focus position by focusing is detected by the focus encoder 15, and this focus position information is sent to the sub CPU 20.

In this embodiment, a DC motor is used for the zoom motor M1 and the focus motor M2, and the zoom position and the focus position are detected by the zoom encoder 14 and the focus encoder 15, however, the zoom motor M1 and the focus motor For example, a stepping motor may be used for M2. In the stepping motor, the zoom position and the focus position can be detected by counting the number of motor steps from the initial position.

The sub CPU 20 drives the zoom motor M1 via the driver IC 22 and drives the focus motor M2 via the driver IC 23 based on an imaging command from the main CPU 21 to perform zooming and focusing.

The image pickup device B is constituted by a CCD, held in an element holder 30, converts an optical image into an electric signal, performs image processing in an image processing section 31, and sends the image to a main CPU 21. The image processing unit 31 performs an automatic gain control for controlling a bright signal or a dark signal to a certain fixed amount by AGC using the reset signal as a video signal in which the reset noise is reduced by the CDS.

The main CPU 21 is connected to an SDRAM 26 capable of high-speed data input / output, performs data input / output to / from the SDRAM 26, and records an image on the image recording card 27.

The tilt adjusting means C is independently displaceable and disposed on the light-incident back side of the image pickup device B. In this embodiment, as shown in FIG. 3, the piezoelectric elements 40a to 40c
It consists of. The piezoelectric elements 40a to 40c can be constituted by, for example, piezo elements.

The three piezoelectric elements 40a to 40c are arranged so as to form an equilateral triangle surrounding the image sensor B, and are independently driven by the piezoelectric element driving circuit 25. For example, only the piezoelectric element 40a is driven, or only the piezoelectric element 40b is driven, or only the piezoelectric element 40c is driven, or only the piezoelectric elements 40a and 40b are driven, or only the piezoelectric elements 40b and 40c are driven. Alternatively, by driving only the piezoelectric elements 40c and 40a, the inclination θ1 of the imaging surface b of the imaging device B is changed to adjust the angle between the imaging surface b and the optical axis o.

At the time of manufacturing, the inclination θ1 of the image pickup surface b of the image pickup device B is changed according to the movement of the lens by the piezoelectric elements 40a to 40c to adjust the angle between the image pickup surface b and the optical axis o. The adjustment value is stored in the storage unit D via the sub CPU 20 in advance. The storage means D is composed of an EEPROM 50 as a rewritable nonvolatile memory.

The imaging optical system of this embodiment can perform zooming and focusing, and
The adjustment values by the tilt adjustment means C at the zooming position and the focusing position during the manufacture of the
By storing the values in 50, the piezoelectric elements 40a to 40c are driven based on the tilt adjustment values stored in advance corresponding to the zooming and focusing at the time of shooting to change the inclination θ1 of the imaging surface b of the imaging element B. The most suitable tilt adjustment can be performed.

The sub CPU 20 drives the piezoelectric elements 40a to 40c based on the tilt adjustment value stored in the storage means D in advance according to the lens movement position at the time of photographing, and varies the inclination θ1 of the imaging surface b of the imaging device B. The control unit E is configured to change the tilt adjustment value in accordance with the movement of the lens at the time of photographing, and to perform an optimum tilt adjustment of the image sensor B in response to the change each time, thereby obtaining an image with less one-sided blur and peripheral blur. Can be

The piezoelectric elements 40a to 40c constituting the three independently displaceable moving means of the tilt adjusting means C include:
Although it is arranged on the back side of the image sensor B on which light is incident, FIG.
As shown by the two-dot chain line, the image pickup device B may be arranged on the light incident surface side of the image pickup device B, and the image pickup device B can be set to the optimum tilt position with a simple configuration by the operation of the piezoelectric elements 40a to 40c. It is.

Further, the tilt adjusting means C comprises three piezoelectric elements 40a to 40c which constitute three independently displaceable moving means.
However, the present invention is not limited to this. For example, one independent displaceable moving means can be used to move about one location as a fulcrum to perform tilt adjustment.
It is also possible to adjust the tilt in the vertical and horizontal directions by moving with the position as a fulcrum, and four or more independently displaceable moving means may be used.

Further, the piezoelectric element may be constituted by one sheet, or may be constituted by laminating a plurality of sheets. In a configuration in which a plurality of piezoelectric elements are stacked, the moving distance can be arbitrarily adjusted by the number of driven piezoelectric elements.

FIG. 4 is a block diagram of another embodiment of the tilt adjusting means. The tilt adjusting means C of this embodiment includes:
The wedge-shaped prism 60 is arranged in front of the imaging device B. The optical axis angle θ2 is changed by changing the position of the wedge-shaped prism 60, and the angle between the imaging surface b and the optical axis o is adjusted. The wedge-shaped prism 60 can be arranged in the imaging optical system A as shown by a two-dot chain line.

The wedge-shaped prism 60 is composed of, for example, two flat surfaces and an expandable / contractible wall, and has a liquid sealed therein.
By changing the position of the wedge-shaped prism 60, the optical axis angle θ2 can be inclined. With a simple configuration using the wedge-shaped prism 60, the optical axis angle can be varied to perform the optimal tilt adjustment.

[0038]

As described above, according to the first aspect of the present invention, the angle between the imaging surface of the image sensor and the optical axis is adjusted in accordance with the movement of the lens, and the tilt adjustment value at this lens movement position is set in advance. It is stored, and the tilt adjusting means is driven based on the tilt adjusting value stored in advance in the storage means according to the lens moving position at the time of shooting, and the tilt adjusting value is changed according to the lens movement, and each time the lens moves, By performing the optimal tilt adjustment corresponding to the lens movement position, an image with less one-sided blur and peripheral blur can be obtained.

According to the second aspect of the present invention, the adjustment values at the zooming position and the focusing position are stored in advance, so that the tilt is adjusted based on the tilt adjustment values stored in advance corresponding to the zooming and focusing at the time of photographing. By driving the adjusting means, it is possible to perform the optimum tilt adjustment.

According to the third aspect of the present invention, the tilt of the image pickup surface of the image pickup device can be varied to adjust the angle between the image pickup surface and the optical axis, thereby making it possible to perform the optimum tilt adjustment.

According to the fourth aspect of the present invention, it is possible to set the image pickup device at the optimum tilt position with a simple configuration using the piezoelectric element that can be independently displaced and is disposed on the light incident surface side or the back side of the image pickup device. It is possible.

According to the fifth aspect of the present invention, the optical axis angle of the image pickup optical system can be changed to adjust the angle between the image pickup surface and the optical axis, thereby making it possible to perform the optimum tilt adjustment.

According to the sixth aspect of the present invention, the optimum tilt adjustment can be performed with a simple configuration using a wedge-shaped prism capable of changing the optical axis angle.

[Brief description of the drawings]

FIG. 1 is a block diagram of an imaging device applied to a digital camera.

FIG. 2 is a configuration diagram of a tilt adjustment unit.

FIG. 3 is a diagram showing an arrangement of piezoelectric elements.

FIG. 4 is a configuration diagram of another embodiment of the tilt adjustment means.

[Explanation of symbols]

 A imaging optical system B imaging element C tilt adjustment means D storage means E control means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 7/18 G03B 5/08 G03B 5/08 H04N 5/225 D H04N 5/225 101: 00 // H04N 101: 00 G02B 7/18 A F term (reference) 2H042 CA00 CA17 2H043 AA02 AA24 BA00 2H044 AC03 DA01 DA02 DA03 DA04 DB04 DC01 5C022 AA13 AB22 AB45 AB66 AC42 AC51 AC54 AC69 AC74

Claims (6)

[Claims] An imaging optical system for moving a lens to capture an image;
An image pickup device having an image pickup device for converting an optical image by the image pickup optical system into an electric signal, a tilt adjusting means for adjusting an angle between an image pickup surface of the image pickup device and an optical axis according to movement of a lens, and the lens Storage means for previously storing the tilt adjustment value at the movement position; and an imaging surface of the image sensor by driving the tilt adjustment means based on the tilt adjustment value stored in the storage means in advance according to the lens movement position at the time of shooting. An image pickup apparatus comprising: a control unit that adjusts an angle between the optical axis and an optical axis. 2. The imaging apparatus according to claim 1, wherein the imaging optical system is capable of performing zooming and focusing, and stores in advance the tilt adjustment values at the zooming position and the focusing position. 3. The apparatus according to claim 1, wherein the tilt adjustment means adjusts an angle between the imaging surface and an optical axis by changing a tilt of an imaging surface of the imaging device. Imaging device. 4. An image pickup apparatus according to claim 3, wherein said tilt adjustment means is an independently displaceable piezoelectric element disposed on a light beam incident surface side or a back side of said image pickup device. 5. The apparatus according to claim 1, wherein the tilt adjustment means adjusts an angle between the imaging surface and the optical axis by changing an optical axis angle of the imaging optical system. Imaging device. 6. The image pickup apparatus according to claim 5, wherein said tilt adjustment means is a wedge-shaped prism disposed in front of said image pickup device or in an image pickup optical system and capable of changing an optical axis angle.