Patent Application
20070122132
1. Field of the Invention
The present invention relates to a camera shake compensation unit which has a mechanism to compensate for a camera shake, an image taking apparatus which shoots an image formed by light incident from a subject, an image taking system and a method of compensating for an image formation position by compensating displacement of an image formation position.
2. Description of the Related Art
Recently, an image taking apparatus such as a digital camera has been popular and many people enjoy taking a photo.
When they takes a photo by using the image taking apparatus, pressing a shutter button may cause a camera shake. Also, in a manufacturing process of an image taking apparatus, so-called eccentricity of an optical device may occur by mounting an optical device and an image taking device in a displaced position relative to each other. Such a camera shake and an eccentricity of an optical device bring about displacement of an image formation position, resulting in displacement of an image formed by shooting.
In order to compensate for a camera shake, some image taking apparatuses have a mechanism to compensate for the effect of shakes of these image taking apparatuses at the moment when a shutter button is pressed, by changing a position of an optical device or an image taking device along an optical axis (e.g., Japanese Patent Laid-Open No. S50-80854 and Japanese Patent Laid-Open No. S62-47013). On the other hand, regarding an eccentricity of the optical device, there is proposed a compensation method to compensate for the effect of an eccentricity of the optical device which makes use of a mechanism to change a configuration of a mirror mounted in an optical system (e.g., Japanese Patent Laid-Open No. 2003-287612 and Japanese Patent Laid-Open No. 2005-49598).
Driving force generated by a small motor is ordinarily used as a source of driving force for changing a position of an optical device or an image taking device. However, the means by a small motor is unsuitable to significantly reduce size of an image taking apparatus due to technical difficulties. As a result, this means by a small motor can not satisfy the recent requirement in the field of image taking apparatuses for a smaller-sized image taking apparatus. On the other hand, it is disadvantageous in view of reduction in size and manufacturing cost to change a shape of a mirror to be mounted in an image taking apparatus in order to compensate for the effect of an eccentricity of the optical device, because the mounted mechanism is not needed any more after adjustment of the eccentricity.
The present invention has been made in view of the above circumstances, and provides a camera shake compensation unit, an image taking apparatus, an image taking system and a method of compensating for an image formation position which are suitable for miniaturization.
The present invention provides a camera shake compensation unit including:
(1) a mobile optical device which allows light incident from a subject to run through the mobile optical device and changes the direction of the light by moving on a two-dimensional plane which intersects with the direction along the light;
(2) a camera shake detection section which detects a camera shake;
(3) a polymer actuator having:
(4) a camera shake compensation section which compensates for displacement of light incident from a subject caused by a camera shake, by supplying a voltage corresponding to a detection result by the camera shake detection section to the plurality of electrodes in order to move the mobile optical device on the two-dimensional plane.
The first camera shake compensation unit according to the present invention can carry out compensation for a camera shake by moving the mobile optical device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. The mechanism to compensate for a camera shake is so simple that the first camera shake compensation unit according to the present invention is appropriate for realizing smaller size.
The present invention also provides a camera shake compensation unit including:
(1) a mobile optical device which allows light incident from a subject to run through the mobile optical device and changes the direction of the light by tilting toward the direction along the light;
(2) a camera shake detection section which detects a camera shake;
(3) polymer actuators having:
(4) a camera shake compensation section which compensates for displacement of light incident from a subject caused by a camera shake, by supplying a voltage corresponding to a detection result by the camera shake detection section to the plurality of electrodes in order to tilt the mobile optical device.
The second camera shake compensation unit according to the present invention can carry out compensation for a camera shake by tilting the mobile optical device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. The mechanism to compensate for a camera shake is so simple that the second camera shake compensation unit according to the present invention is also appropriate for realizing smaller size.
The present invention also provides a camera shake compensation unit including:
(1) a mobile optical device which allows light incident from a subject to run through the mobile optical device and changes the direction of the light by tilting toward the direction along the light;
(2) a camera shake detection section which detects a camera shake;
(3) a polymer actuator having:
(4) a camera shake compensation section which compensates for displacement of light incident from a subject caused by a camera shake, by supplying a voltage corresponding to a detection result by the camera shake detection section to the plurality of electrodes in order to tilt the mobile optical device.
The third camera shake compensation unit according to the present invention can carry out compensation for a camera shake by tilting the mobile optical device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. The mechanism to compensate for a camera shake is so simple that the third camera shake compensation unit according to the present invention is also appropriate for realizing smaller size.
Also, in the first, second and third camera shake compensation units according to the present invention, preferably the mobile optical device is a lens.
The preferred forms of the camera shake compensation units can easily carry out compensation for a camera shake by driving the lens only using application of a voltage to the polymer actuator.
Also, the first and third camera shake compensation units according to the present invention, preferably includes:
an optical membrane which is a membrane made of a transparent material that light runs through, the optical membrane configured as:
The preferred forms of the camera shake compensation units do not need a holder and something like that which hold the mobile optical device. As a result, the structure of these preferred forms of the camera shake compensation units is simplified.
Also, in the first and third camera shake compensation units according to the present invention, preferably the mobile optical device is an optical wedge.
The preferred forms of the camera shake compensation units can easily carry out compensation for a camera shake by driving the optical wedge only using application of a voltage to the polymer actuator.
The present invention also provides a camera shake compensation unit including:
(1) an image taking device which receives light incident from a subject and generates image signals, and changes a position of receiving the light by moving on a two-dimensional plane which intersects with the direction along the light;
(2) a camera shake detection section which detects a camera shake;
(3) a polymer actuator having:
(4) a camera shake compensation section which compensates for displacement of light incident from a subject caused by a camera shake, by supplying a voltage corresponding to a detection result by the camera shake detection section to the plurality of electrodes in order to move the image taking device on the two-dimensional plane.
The fourth camera shake compensation unit according to the present invention can carry out compensation for a camera shake by moving the mobile image taking device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. The mechanism to compensate for a camera shake is so simple that the fourth camera shake compensation unit according to the present invention is also appropriate for realizing smaller size.
Also, in the first and fourth camera shake compensation units according to the present invention, preferably the camera shake compensation section applies a voltage of a value corresponding to the detected result of the camera shake detection section.
The preferred forms of the camera shake compensation units can carry out compensation for a camera shake by applying an appropriate voltage corresponding to the detected result of the camera shake detection section.
Also, in the first and fourth camera shake compensation units according to the present invention, preferably the camera shake compensation section supplies pulse voltages of a pulse width corresponding to the detected result of the camera shake detection section.
Many polymer actuators are luck of ability to quickly respond to an applied voltage. It is available to use pulse voltages as a voltage applied to these polymer actuators whose pulse width is much shorter than the response time of these polymer actuators because these polymer actuators feel an effectively averaged voltage of pulse voltages by the response time. Moreover, it is also possible to change the averaged voltage by controlling the pulse width. Therefore the above preferred forms of the camera shake compensation units can carry out compensation for a camera shake by applying an effectively appropriate voltage corresponding to detected results of the camera shake detection section.
Also, in the first and fourth camera shake compensation units according to the present invention, preferably the polymer membrane expands and contracts as much as an amount corresponding to an average of an applied voltage in the case that the applied voltage is varied with passage of time.
The preferred forms of the camera shake compensation units can easily carry out compensation for a camera shake by applying an appropriate voltage obtained by averaging an applied voltage corresponding to a camera shake, even if the an applied voltage changes with passage of time.
Also, in the first and fourth camera shake compensation units according to the present invention, preferably the polymer membrane expands and contracts in response to release of an applied voltage, and the camera shake compensation section releases a voltage supplied to the electrodes for a compensation for a camera shake, instead of supplying a voltage.
The preferred forms of the camera shake compensation units can easily carry out compensation for a camera shake by releasing an appropriate voltage corresponding to a camera shake.
The present invention also provides an image taking apparatus which shoots a subject including:
(1) a mobile optical device which allows light incident from a subject to run through the mobile optical device and changes the direction of the light by moving on a two-dimensional plane which intersects with the direction along the light;
(2) a camera shake detection section which detects a camera shake;
(3) a polymer actuator having:
(4) a camera shake compensation section which compensates for displacement of light incident from a subject caused by a camera shake, by supplying a voltage corresponding to a detection result by the camera shake detection section to the plurality of electrodes in order to move the mobile optical device on the two-dimensional plane.
The first image taking apparatus according to the present invention can carry out compensation for a camera shake by moving the mobile optical device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. The mechanism to compensate for a camera shake is so simple that the first image taking apparatus according to the present invention is appropriate for realizing smaller size.
The present invention also provides an image taking apparatus which shoots a subject including:
(1) a mobile optical device which allows light incident from a subject to run through the mobile optical device and changes the direction of the light running through the mobile optical device by tilting toward the direction along the light;
(2) a camera shake detection section which detects a camera shake;
(3) polymer actuators having:
(4) a camera shake compensation section which compensates for displacement of light incident from a subject caused by a camera shake, by supplying a voltage corresponding to a detection result by the camera shake detection section to the plurality of electrodes in order to tilt the mobile optical device.
The second image taking apparatus according to the present invention can carry out compensation for a camera shake by tilting the mobile optical device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. The mechanism to compensate for a camera shake is so simple that the second image taking apparatus according to the present invention is also appropriate for realizing smaller size.
The present invention also provides an image taking apparatus which shoots a subject including:
(1) a mobile optical device which allows light incident from a subject to run through the mobile optical device and changes the direction of the light running through the mobile optical device by tilting toward the direction along the light;
(2) a camera shake detection section which detects a camera shake;
(3) a polymer actuator having:
(4) a camera shake compensation section which compensates for displacement of light incident from a subject caused by a camera shake, by supplying a voltage corresponding to a detection result by the camera shake detection section to the plurality of electrodes in order to tilt the mobile optical device.
The third image taking apparatus according to the present invention can carry out compensation for a camera shake by tilting the mobile optical device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. The mechanism to compensate for a camera shake is so simple that the third image taking apparatus according to the present invention is also appropriate for realizing smaller size.
The present invention also provides an image taking apparatus which shoots a subject including:
(1) an image taking device which receives light incident from a subject and generates image signals, and changes a position of receiving the light by moving on a two-dimensional plane which intersects with the direction along the light;
(2) a camera shake detection section which detects a camera shake;
(3) a polymer actuator having:
(4) a camera shake compensation section which compensates for displacement of light incident from a subject caused by a camera shake, by supplying a voltage corresponding to a detection result by the camera shake detection section to the plurality of electrodes in order to move the image taking device on the two-dimensional plane.
The fourth image taking apparatus according to the present invention can carry out compensation for a camera shake by moving the mobile image taking device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. The mechanism to compensate for a camera shake is so simple that the first image taking apparatus according to the present invention is also appropriate for realizing smaller size.
The present invention also provides an image taking system having:
(1) an image taking apparatus which forms an image based on light incident from a subject and generates image signals which represent the subject image; and
(2) an image formation position compensation unit which is mounted on the image taking apparatus removably and control the image taking apparatus to compensate for displacement of image formation position of the light,
the image taking system including:
(A) an image taking apparatus including;
The image taking system according to the present invention can carry out compensation for displacement of an image formation position by moving the mobile optical device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. The mechanism to compensate for displacement of an image formation position is so simple and the polymer actuator is so cheap that the first image taking system according to the present invention is appropriate for realizing smaller size and lower cost.
Also, in the image taking system according to the present invention, preferably the mobile optical device is a lens.
The preferred forms of the image taking system can easily carry out compensation for displacement of an image formation position by driving the lens only using application of a voltage to the polymer actuator.
Also, the image taking system and the image taking system with the lens as the mobile optical device according to the present invention, preferably includes:
an optical membrane which is a membrane made of a transparent material that light runs through, the optical membrane configured as:
The preferred forms of the image taking systems do not need a holder and something like that which hold the mobile optical device. As a result, the structure of these preferred forms of the image taking systems is simplified.
Also, in the image taking system according to the present invention, preferably the image taking apparatus includes:
an image signal generation section which generates image signals by receiving light incident from a subject which runs through the mobile optical device;
the image taking system further including:
a displacement calculation section which calculates an amount of displacement of image formation position of light incident from a subject based on the image signal; and
the displacement compensation section recognizing the amount of displacement of image formation position by obtaining the amount of displacement of image formation position calculated by the displacement calculation section.
The preferred forms of the image taking system can easily carry out compensation for displacement of an image formation position by calculating an amount of displacement of an image formation position of light incident from a subject from image signals.
Also, in the image taking system according to the present invention, preferably the displacement compensation section applies a voltage of a value corresponding to the amount of displacement of image formation position.
The preferred form of the image taking system can carry out compensation for displacement of an image formation position by applying an appropriate voltage corresponding to an amount of displacement of an image formation position.
Also, in the image taking system according to the present invention, preferably the displacement compensation section supplies pulse voltages of a pulse width corresponding to the amount of displacement of image formation position.
Many polymer actuators are luck of ability to quickly respond to an applied voltage. It is available to use pulse voltages as a voltage applied to these polymer actuators whose pulse width is much shorter than the response time of these polymer actuators because these polymer actuators feel an effectively averaged voltage of pulse voltages by the response time.
Moreover, it is also possible to change the averaged voltage by controlling the pulse width. Therefore the above preferred form of the image taking system can carry out compensation for displacement of an image formation position by applying an effectively appropriate voltage corresponding to an amount of displacement of an image formation position.
Also, in the image taking system according to the present invention, preferably the image taking apparatus comprising a position fixing section which fixes the mobile optical device on position where displacement of the image formation position is compensated.
In the preferred form of the image taking system, it is possible to fix the mobile optical device on the appropriate position to compensate for displacement of an image formation position even after the application of a voltage to the polymer actuator is stopped. In addition to that, there is another merit that the polymer actuator is useful as a damper due to its elasticity for impact on the image taking system from outside when the image taking system is used, even though the role of polymer actuator has already finished after the fixing the mobile optical device. As a result, the polymer actuator produces an effect to reduce the damage of the mobile optical device originated from the impact.
Also, in the image taking system according to the present invention and the image taking system in which pulse voltages are applied according to the present invention, preferably the polymer membrane expands and contracts as much as an amount corresponding to an average of an applied voltage in the case that the applied voltage is varied with passage of time.
The preferred forms of the image taking systems can easily carry out compensation for displacement of an image formation position by applying an appropriate voltage obtained by averaging an applied voltage corresponding to displacement of an image formation position, even if the an applied voltage varies with passage of time.
Also, in the image taking system according to the present invention, preferably the polymer membrane expands and contracts in response to release of an applied voltage, and the displacement compensation section releases a voltage supplied to the electrodes for a compensation for displacement of the image formation position.
The preferred form of the image taking system can easily carry out compensation for displacement of an image formation position by releasing an appropriate voltage corresponding to displacement of an image formation position.
The present invention also provides a compensation method of image formation position of light incident from a subject in an image taking apparatus which forms an image based on light incident from a subject and generates image signals which represent the subject image, the compensation method of image formation position including:
(1) recognizing an amount of displacement of image formation position of light incident from a subject;
(2) compensating for the displacement of the image formation position of the light using a polymer actuator, the polymer actuator having;
The compensation method of image formation position according to the present invention can carry out compensation for displacement of an image formation position by moving the mobile optical device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. Then, the mobile optical device is fixed on the appropriate position to compensate for displacement of an image formation position. The mechanism to compensate for displacement of an image formation position is so simple and the polymer actuator is so cheap that the first image taking system according to the present invention is appropriate for realizing smaller size and lower cost. In addition to that, there is another merit that the polymer actuator is useful as a damper due to its elasticity for impact on the image taking system from outside when the image taking system is used, even though the role of polymer actuator has already finished after the fixing the mobile optical device. As a result, the polymer actuator produces an effect to reduce the damage of the mobile optical device originated from the impact.
The present invention provides a camera shake compensation unit including:
(1) an image taking device which receives light incident from a subject and generates image signals, and changes a position of receiving the light by rotating on a two-dimensional plane which intersects with the direction along the light;
(2) a camera shake detection section which detects a camera shake;
(3) a polymer actuator having:
(4) a camera shake compensation section which compensates for displacement of light incident from a subject caused by a camera shake, by supplying a voltage corresponding to a detection result by the camera shake detection section to the plurality of electrodes in order to rotate the image taking device on the two-dimensional plane.
The fifth camera shake compensation unit according to the present invention can carry out compensation for a camera shake which causes rotation of a subject image by rotating the mobile image taking device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. The mechanism to compensate for a camera shake is so simple that the fifth camera shake compensation unit according to the present invention is appropriate for realizing smaller size.
Also, in the fifth camera shake compensation unit according to the present invention, preferably the camera shake compensation section compensates for displacement of light incident from a subject caused by a camera shake, by supplying a voltage corresponding to a detection result by the camera shake detection section to the plurality of electrodes in order to shift and rotate the image taking device on the two-dimensional plane.
The preferred form of the camera shake compensation units can easily carry out compensation for a camera shake which causes rotation and shift of a subject image only by using application of a voltage to the polymer actuator.
Also, in the fifth camera shake compensation unit according to the present invention, preferably the camera shake compensation section applies a voltage of a value corresponding to the detected result of the camera shake detection section.
The preferred form of the camera shake compensation unit can carry out compensation for a camera shake by applying an appropriate voltage corresponding to detected results of the camera shake detection section.
Also, in the fifth camera shake compensation unit according to the present invention, preferably the camera shake compensation section supplies pulse voltages of a pulse width corresponding to the detected result of the camera shake detection section.
Many polymer actuators are luck of ability to quickly respond to an applied voltage. It is available to use pulse voltages as a voltage applied to these polymer actuators whose pulse width is much shorter than the response time of these polymer actuators because these polymer actuators feel an effectively averaged voltage of pulse voltages by the response time. Moreover, it is also possible to change the averaged voltage by controlling the pulse width. Therefore the above preferred form of the camera shake compensation unit can carry out compensation for a camera shake by applying an effectively appropriate voltage corresponding to detected results of the camera shake detection section.
Also, in the fifth camera shake compensation unit according to the present invention, preferably the polymer membrane expands and contracts as much as an amount corresponding to an average of an applied voltage in the case that the applied voltage is varied with passage of time.
The preferred form of the camera shake compensation unit can easily carry out compensation for a camera shake by applying an appropriate voltage obtained by averaging an applied voltage corresponding to a camera shake, even if the an applied voltage changes with passage of time.
Also, in the fifth camera shake compensation unit according to the present invention, preferably the polymer membrane expands and contracts in response to release of an applied voltage, and the camera shake compensation section releases a voltage supplied to the electrodes for a compensation for a camera shake, instead of supplying a voltage.
The preferred form of the camera shake compensation unit can easily carry out compensation for a camera shake by releasing an appropriate voltage corresponding to a camera shake.
The present invention also provides an image taking apparatus which shoots a subject including:
(1) an image taking device which receives light incident from a subject and generates image signals, and changes a position of receiving the light by rotating on a two-dimensional plane which intersects with the direction along the light;
(2) a camera shake detection section which detects a camera shake;
(3) a polymer actuator having:
(4) a camera shake compensation section which compensates for displacement of light incident from a subject caused by a camera shake, by supplying a voltage corresponding to a detection result by the camera shake detection section to the plurality of electrodes in order to rotate the image taking device on the two-dimensional plane.
The fifth image taking apparatus according to the present invention can carry out compensation for a camera shake which causes rotation of a subject image by rotating the mobile image taking device on the plane which intersects with the direction along light incident from a subject only using application of a voltage to the polymer actuator. The mechanism to compensate for a camera shake is so simple that the first image taking apparatus according to the present invention is appropriate for realizing smaller size.
As described above, the present invention provides a camera shake compensation unit, an image taking apparatus, an image taking system and a method of compensating for an image formation position which are suitable for miniaturization.
The invention will be described with reference to the accompanying figures of which:
The first embodiment of the present invention will be described below.
On the upper front part of the digital camera 1 shown in
Various switches such as a zoom control switch and cross-key pad as well as an LCD (liquid crystal display) for use to display images and a menu screen are mounted on the back (not shown) of the digital camera.
The digital camera 1 has all its processes controlled by a CPU 120. The CPU 120 is supplied with operation signals from various switches (which include the shutter button 14 shown in
The configuration of the digital camera 1 is described below by explaining a flow of an image signal.
Light incident from a subject represented by a dotted line in the figure passes through the image taking lens 10 which consists of plural lenses, and an iris unit 30 and then forms an image on a CCD 40, which then generates an image signal representing a subject image.
A compensation lens 20 is included in the plural lenses constituting the image taking lens 10. As described later, compensation for a camera shake is carried out by moving the compensation lens 20 on the plane which is perpendicular to the direction along light incident from a subject, using a polymer actuator which is mounted near the compensation lens 20.
The generated image signal is roughly read by an A/D section 131, which then converts an analog signal into a digital signal to generate low-resolution live view data. The generated live view data are subjected to image processing such as white balance compensation and γ compensation by a white balance and γ processing section 133.
The CCD 40 generates the image signal at predetermined intervals in sync with a timing signal supplied from a clock generator 132. The clock generator 132 outputs the timing signal based on instructions transmitted from the CPU 120. In addition to the CCD 40, the timing signal is also supplied to the A/D section 131 and the white balance and γ processing section 133 in subsequent stages. Thus, the CCD 40, A/D section 131, and white balance and γ processing section 133 process the image signal in an orderly manner in sync with the timing signal generated by the clock generator 132.
After the image processing by the white balance and γ processing section 133, the image data are temporarily stored in a buffer memory 134. The low-resolution live view data stored in the buffer memory 134 are supplied to a YC/RGB conversion section 138 via the bus 140 in the order in which they are stored. The live view data are provided as RGB signals, and thus they are not processed by the YC/RGB conversion section 138. Instead, they are transmitted directly to an image display LCD 160 via a driver 139, and a live view from the live view data is displayed on the image display LCD 160. The CCD 40 reads light incident from a subject and generates an image signal at the predetermined intervals, and thus the light incident from a subject coming from the direction in which the image taking lens is directed is displayed constantly on the image display LCD 160.
The live view data stored in the buffer memory 134 are also supplied to the CPU 120. Based on the live view data, the CPU 120 carries out auto-focus process and automatic exposure adjustment.
When the user presses the shutter button 14 shown in
The digital camera 1 has a camera shake detection section 450 which detects a camera shake by measuring an angular frequency, a voltage adjustment section 503 which adjusts a voltage applied to the polymer actuator 500, a controller 505 which controls the voltage adjustment section 503. If a camera shake occurs at the moment when the shutter button 14 is pressed, the camera shake detection section 450 detects the camera shake and information about the camera shake is transmitted to the controller 505. Using a mechanism described later, the controller 505 compensates for the camera shake by moving the compensation lens 20 on the plane which is perpendicular to the direction along light incident from a subject.
When the image taking is carried out by pressing the shutter button 14, based on instructions from the CPU 120, the image signals generated by the CCD 40 are read out finely by the A/D section 131 to generate high-resolution photographic image data. The generated photographic image data is subjected to image processing by the white balance and γ processing section 133 and stored in the buffer memory 134.
The photographic image data stored in the buffer memory 134 is supplied to a YC processing section 137, where they are converted from an RGB signal to a YC signal. After the conversion into the YC signal, the photographic image data is subjected to a compression process by a compression/decompression section 135. The compressed photographic image data is stored in a memory card 170 via an interface 136.
The photographic image data stored in the memory card 170 is subjected to a decompression process by the compression/decompression section 135, converted into an RGB signal by the YC/RGB conversion section 138, and transmitted to the image display LCD 160 via the driver 139. The image display LCD 160 displays a photographic image represented by the photographic image data.
The digital camera 1 is configured as described above.
As described above, the digital camera 1 has a mechanism to compensate for a camera shake by moving the already-mentioned compensation lens 20 on the plane which is perpendicular to the direction along light incident from a subject if a camera shake is detected at the moment when the shutter button 14 is pressed. Details on the mechanism to compensate for a camera shake will be described below.
The digital camera 1 has the polymer actuator 500 to move this compensation lens 20 shown in
The polymer actuator 500 includes electrodes 502a, 502b, 502c, 502d and a dielectric elastomer 501 which is a kind of polymer material which has a property to expand and contract in response to application of a voltage. Each of electrodes 502a, 502b, 502c, 502d is made of carbon fiber with high conductivity and is put on the dielectric elastomer 501. There are four electrodes respectively on the upper and lower side of the polymer actuator 500. The four electrodes on the upper side are anodes and the four electrodes on the lower side are cathodes, that is, they constitute four pairs of electrodes in which an anode and a cathode constitute one pair. In this figure, the four anodes of the four pairs of electrodes 502a, 502b, 502c, 502d are shown on the upper side by diagonal lines. The dielectric elastomer 501 has a shape of a square with a round hole on its center by which the round holder 506 is surrounded. In
The above structure of the polymer actuator 500 makes it possible to apply voltages of different values to the respective four parts of the dielectric elastomer 501 sandwiched between the four electrodes on the upper side and the four electrodes on the lower side. Then a mechanism to apply voltages with different values to the four parts will be described below.
In this structure, there are four sets which consist of four pairs of electrodes 502a, 502b, 502c, 502d and four voltage adjustment sections 503a, 503b, 503c, 503d in which one set consists of a pair of electrodes and a voltage adjustment section consists in one set, and the four sets are connected with the power 102 in parallel as shown in
Incidentally, voltages are thus supplied by the power 102 in the embodiment. However, it may be possible to use high voltage supplied to the flash emission section 12.
The two electrodes 502c in the left of
Next, description will be made of how the compensation lens 20 and the holder 506 are moved by application of a voltage to the polymer actuator 500 in order to compensate for a camera shake.
When a camera shake occurs and the camera shake detection section 450 in
Description will be made below, as an example, on the supposition that the determination to supply a voltage to the two electrodes in the left of
In general, a dielectric elastomer has a property that it expands in the direction along the electrodes which applies a voltage to the dielectric elastomer. The length of the expansion is longer as an applied voltage increases. On the other hand, the four pairs of electrodes 502a, 502b, 502c, 502d in the embodiment can expand and contract according to the expansion and contraction of the parts of dielectric elastomer 501 on which these pairs of electrodes are placed on when voltages are applied.
Because of the above mentioned property of a dielectric elastomer, a part of the dielectric elastomer 501 between the two electrodes expands from the state shown in the left of
Such application of a voltage is carried out to each part of the dielectric elastomer 501 which is sandwiched between the electrode on the upper side and the electrode on the lower side. As a result, the lens 20 and the holder 506 are moved on the plane which is perpendicular to the direction along light incident from a subject, and a camera shake is compensated by this movement.
As described above, the mechanism using the digital camera 1 enables driving the compensation lens 20 for compensation for a camera shake with the simpler configuration compared with conventional one using a compact motor, and thus enables realization of a smaller image taking apparatus.
The external frame 507 shown in
As shown in
Therefore, the end part of the polymer actuator 500 is tightly fixed, although the structure for fixing is very simple.
The description of the first embodiment of the present invention is completed above.
In the first embodiment, the compensation lens 20 is connected with the polymer actuator 500 via the holder 506. However, the present invention is not limited to this method and the embodiment described above may employ another method in which a transparent dielectric elastomer that light easily runs through is used to connect the compensation lens 20 directly with the polymer actuator 500 without using the holder 506. Description of such an embodiment will be made below as the second embodiment. The following second embodiment is different from the first embodiment in a point that the compensation lens 20 is directly connected with the polymer actuator 500 without using the holder 506. Except this point, an external view, a structure and a mechanism to compensate for a camera shake of an image taking apparatus in the second embodiment are the same as those of the image taking apparatus in the first embodiment. Thus, the description below will focus on the point that the compensation lens 20 is directly connected with the polymer actuator 500 without repeating the same description which has been already made above.
A dielectric elastomer 501′ used in the embodiment has excellent transparency and a part of the dielectric elastomer 501′ is attached on the surface of the compensation lens 20 as shown in
In the first and second embodiments, the compensation lens 20 is a single lens. However, the present invention is not limited to this type and the embodiment described above may employ a combination lens to compensate for a camera shake. Description of such an embodiment will be made below as the third embodiment. The following third embodiment is different from the second embodiment in points that a compensation lens in the third embodiment is a combination lens and that another structure is provided to hold the combination lens besides the dielectric elastomer in order to support the increased weight of the compensation lens. Except these points, an external view, a structure and a mechanism to compensate for a camera shake of an image taking apparatus in the third embodiment are the same as those of the image taking apparatus in the second embodiment. Thus, the description below will focus on the different point without repeating the same description which has been already made above.
As shown in
In the first to third embodiments described above, the external frame 507 to fix the polymer actuator has a square cross section with respect to the plane which is perpendicular to the direction along light incident from a subject. However, the present invention is not limited to this shape and the embodiments described above may employ an external frame whose cross section is circular. Description of such an embodiment will be made below as the fourth embodiment.
Four pairs of electrodes in which one pair consists of an anode and a cathode are mounted in the fourth embodiment in the same way as the case shown in
In the first to fourth embodiments described above, the voltages to be supplied to the four pairs of electrodes to drive the polymer actuator is adjusted by adjustment of the values of the voltages. However, the present invention is not limited to this adjustment method and the embodiments described above may employ another adjustment method, for example, a so-called PWM control method in which adjustment of time intervals when a voltage is applied is carried out in order to control drive of a mobile optical device for compensation for a camera shake, although voltage application has only two stages of On and Off. Description of such an embodiment will be made below as the fifth embodiment.
As shown in
Incidentally, the method of controlling the pulse width of the applied voltage which consists of a series of square-wave pulse voltages is employed in order to control the effective voltage in the fifth embodiment. However, the present invention is not limited to this method and the embodiment described above may employ another method in which voltage is controlled by controlling a period of an applied voltage which consists of a series of square-wave pulse voltages.
Turning on and off of voltage application to the polymer actuator is carried out by the four switches in the fifth embodiment. However, the present invention is not limited to this and the embodiment described above may employ a circuit element such as a thyristor and a MOS-type FES which turns on and off the electric current in order to control turning on and off of a voltage applied to the polymer actuator 500.
Incidentally, voltages are supplied by the power 102 in the fifth embodiment. However, it may be possible to use high voltage supplied to the flash emission section 12.
Except a point that the CCD is driven under the control of the pulse width of a series of square-wave pulse voltages generated by the voltage application of two stages of On and Off, an external view, a structure and a mechanism to compensate for a camera shake of an image taking apparatus in the fifth embodiment are the same as those of the image taking apparatus in the first embodiment. Thus, the same description which has been already made above is omitted.
In the first to fifth embodiments described above, compensation for a camera shake is carried out by changing the direction of light incident from a subject by moving the compensation lens on the plane which is perpendicular to the direction along light incident from a subject. However, the present invention is not limited to a lens for compensation for a camera shake and the embodiments described above may employ another type of optical device which can change the direction of light incident from a subject. Also, in order to compensate for a camera shake, it is also possible to employ another way to change the direction of light incident from a subject which is different from the way to move the optical device on the plane which is perpendicular to the direction along light incident from a subject. For example, besides a lens, it is also possible to employ an optical device such as an optical wedge to change the direction of light incident from a subject into the image taking apparatus and compensate for a camera shake by tilting the optical device. Description of an embodiment in which the mechanism for driving the compensation lens described in the first to fifth embodiments is applied to a mechanism for control of tilting the optical device to compensate for a camera shake will be made below as the sixth embodiment.
As shown in
When a camera shake occurs and the optical wedge 201 is driven to compensate for the camera shake, a voltage is applied to each of these polymer actuators 500 by making use of the structure to supply voltages in
Incidentally, the optical wedge 201 is driven to rotate for compensation for a camera shake as an example in the sixth embodiment. However, if the embodiment described above employs a lens which is driven to rotate, it is possible to compensate for a camera shake in the same way as the above.
Description of an embodiment in which the different mechanism of tilting an optical device from that of the sixth embodiment is used to compensate for a camera shake will be made below as the seventh embodiment. In this embodiment, a compensation for a camera shake by rotating the compensation lens 20 is described as an example.
There are mounted four polymer actuators 500a, 500b, 500c, 500d two of which are placed two by two on two ends of a lens frame 512 respectively which extends in the upper and lower direction in
When a camera shake occurs and the camera shake detection section 450 in
Description will be made below, as an example, on the supposition that determination to supply a voltage to the pair of electrodes of the left polymer actuator 500a on the far side and to the pair of electrodes of the right polymer actuator 500d on this side is made. The left polymer actuator 500a on the far side in
In the same way, when voltages of the same value are applied to the pair of electrodes of the left polymer actuator 500a on this side and to the pair of electrodes of the right polymer actuator 500d on the far side in
In the embodiment, compensation for a camera shake with respect to the horizontal direction along a subject image (the direction of the line which extends between this side and the far side in
Except for a point that compensation for a camera shake is carried out by rotation of the lens frame 512, an external view and a structure of an image taking apparatus in the seventh embodiment are the same as those of the image taking apparatus in the previous embodiments described in FIGS. 1-
Incidentally, the compensation lens 20 is driven to rotate for compensation for a camera shake as an example in the seventh embodiment. However if the embodiment described above employ an optical wedge to be driven to rotate, it is possible to compensate for a camera shake in the same way as the above.
Also in the seventh embodiment that compensation for a camera shake is carried out by rotation of the lens frame 512, it is possible to employ the method of controlling the pulse width of the applied voltage which is described in
In the seventh embodiment, compensation for a camera shake with respect to the horizontal direction along a subject image (the direction of the line which extends between this side and the far side in
There are mounted additional four polymer actuators 500e, 500f, 500g, 500h besides the four polymer actuators 500a, 500b, 500c, 500d described in
By a mechanism to drive these additional four polymer actuators 500e, 500f, 500g, 500h in order to rotate the lens frame 512 around the Y0 axis which extends through the center of the lens frame 512, compensation for a camera shake with respect to the vertical direction along a subject image (the direction of the line which extends between the upper side and the lower side in
Except for a point that compensation for a camera shake is carried out by the two kinds of rotation of the lens frame 512 around the two axes, an external view and a structure of an image taking apparatus in the eighth embodiment are the same as those of the image taking apparatus in the previous embodiments described in FIGS. 1-
Incidentally, the compensation lens 20 is driven to rotate for compensation for a camera shake as an example in the seventh embodiment. However if the embodiment described above employ an optical wedge as described in the fourth embodiment to be driven to rotate, it is possible to compensate for a camera shake in the same way as the above.
Also in the eighth embodiment that compensation for a camera shake is carried out by rotation of the lens frame 512, it is possible to employ the method of controlling the pulse width of the applied voltage which is described in
In the above eighth embodiment, compensation for a camera shake with respect to horizontal and vertical directions along a subject image is carried out by the eight polymer actuators. However, the present invention is not limited to using eight polymer actuators and the embodiment described above may employ four polymer actuators and four springs to compensate for a camera shake with respect to horizontal and vertical directions along a subject image. Description of such an embodiment will be made below as a ninth embodiment.
In the ninth embodiment, a structure in which the four polymer actuators on the right side of the eight polymer actuators shown in
When a voltage is applied to only the pair of electrodes of the polymer actuator 500e on the upper side in
In the same way, a compensation for a camera shake is carried out by rotating the lens frame 512 around the Y1-axis which extends along the upper surface of the lens frame 512, the Z1-axis which extends along the surface on the far side of the lens frame 512 and the Z2-axis which extends along the surface on this side of the lens frame 512, in the directions in which the polymer actuator expands respectively.
Except for a point that compensation for a camera shake is carried out by the four polymer actuators and the four springs, an external view, a structure and a mechanism to compensate for a camera shake of an image taking apparatus in the ninth embodiment are the same as those of the image taking apparatus in the first embodiment. Thus, the same description which has been already made above is omitted.
Incidentally, the compensation lens 20 is driven to rotate for compensation for a camera shake as an example in the ninth embodiment. However if the embodiment described above employ an optical wedge as described in the fourth embodiment to be driven to rotate, it is possible to compensate for a camera shake in the same way as the above.
Also in the ninth embodiment that compensation for a camera shake is carried out by rotation of the lens frame 512, it is possible to employ the method of controlling the pulse width of the applied voltage which is described in
In the previous embodiments, compensation for a camera shake is carried out by driving an optical device such as a compensation lens and an optical wedge. Description of an embodiment in which compensation for a camera shake is carried out by driving an image taking device (more concretely CCD) will be made below.
In the following description, the same components as those of the internal configuration on
In the internal configuration of the digital camera in
The mechanism to drive the CCD in
The holder 506′ holds the CCD 40, instead of the compensation lens 20 in
Also in the tenth embodiment that compensation for a camera shake is carried out by driving the CCD, it is possible to employ the method of controlling the pulse width of the applied voltage which is described in
Also in the tenth embodiment that compensation for a camera shake is carried out by driving the CCD, it is possible to employ an external frame whose cross section perpendicular to light incident from a subject is circular, as in the case in
It is a point that the holder 506′ holds the CCD 40 in
In the previous embodiments, a camera shake is compensated by application of a voltage of a value which corresponds to the detected camera shake. It is possible to employ another method in which a camera shake is compensated by release of a voltage of a value which corresponds to the detected camera shake. Description of such an embodiment will be made below as the twelfth embodiment.
An external view and a structure of an image taking apparatus in the twelfth embodiment are the same as those of the image taking apparatus in the first embodiment. Thus, the same description which has been already made above is omitted. In the twelfth embodiment, voltages are applied to the polymer actuator before a camera shake is detected. When a camera shake is detected, an appropriate pair of electrodes which corresponds to the detected camera shake is selected and a voltage supplied to the pair of electrodes is released. The dielectric elastomer which expands before the release of a voltage contracts by this release. The compensation lens is driven by the contraction of the polymer actuator and the camera shake is compensated for.
Incidentally, the compensation lens 20 is driven by release of a voltage as an example in the twelfth embodiment. However the embodiment described above may employ a CCD to be driven as in the tenth embodiment. Such an embodiment is the same as that of the twelfth embodiment except for a point that a driven object is a CCD instead of a compensation lens. Thus, the description which has been already made above will be omitted.
Next, embodiments of an image taking system and a compensation method of image formation position according to the present invention will be described below.
In the following description, a digital camera is employed as an example of an image taking apparatus in an image taking system according to the present invention. An external view of the digital camera is the same as that of the digital camera in
It is a point that there is mounted a compensation lens 20 in the rear in the image taking lens 10 and a mechanism to drive the compensation lens 20 by connecting the eccentricity compensation apparatus 520 with the digital camera that the internal configuration of the digital camera in the embodiment is different from that of the digital camera 1 in
A so-called eccentricity of a lens sometimes happens by mounting a lens and a CCD in a position displaced relative to each other in a production process of an image taking apparatuses. The image taking lens 10 in the embodiment contains a compensation lens which compensates for the effect of an eccentricity of a lens. Compensation for an eccentricity is carried out by moving the compensation lens 20 on the plane which is perpendicular to the direction along light incident from a subject using a polymer actuator which is mounted near the compensation lens 20. Also, there is mounted a camera side connector 510a in this digital camera which is connected with an apparatus side connector 510b of the eccentricity compensation apparatus 520. Eccentricity compensation operation is carried out by connecting the apparatus side connector 510b with the camera side connector 510a. The eccentricity compensation apparatus 520 has a calculation section 504, a voltage adjustment section 503 and a controller 505. The calculation section 504 calculates the degree of an eccentricity which represents an amount of displacement of image formation position from image data. The voltage adjustment section 503 adjusts a voltage applied to the polymer actuator 500. The controller 505 obtains a necessary voltage to drive the polymer actuator 500 based on calculation of the calculation section 504 and controls the voltage adjustment section 503. The photographic image data stored in the buffer memory 134 is supplied to the calculation section 504 via the apparatus side connector 510b and the camera side connector 510a for calculation of the degree of an eccentricity. The controller 505 carries out compensation of an eccentricity by moving the compensation lens 20 on the plane which is perpendicular to the direction along light incident from a subject. The eccentricity compensation apparatus 520 is an example of the image formation position compensation unit according to the present invention and the camera side connector 510a is an example of the connection section according to the present invention. A mechanism and a structure to drive the compensation lens 20 is the same as those described in
Next, description of a flow of the eccentricity compensation operation by using the above configurations will be made.
First, the apparatus side connector 510b of the eccentricity compensation apparatus 520 in
In general, an amount of received light decreases as the position where light is received becomes farther from the optical axis on a light-receiving surface of the CCD 40 which receives a light incident from a subject. Therefore, amounts of light received on the edges of the light-receiving surface (for example, four corners of the light-receiving surface) of the CCD 40 is unbalanced in the case that the optical axis of the image taking lens 10 is displaced from the center of the light-receiving surface due to an eccentricity. Making use of this phenomena, a scale of an eccentricity and its direction can be evaluated by analysis of portions of image data which represent a light incident from a subject received on the edges of the light-receiving surface of the CCD 40. The calculation section 504 selects portions of photographic image data from the input photographic image data which are formed based on the light received on the four corners of the light-receiving surface of the CCD 40. Then the calculation section 504 calculates the degree of an eccentricity which represents a scale of an eccentricity and its direction, based on their relative differences of brightness (step S2). More concretely, the degree of an eccentricity represents an amount of displacement of image formation position by x, γ coordinates on the two-dimensional plane (x-y plane) which is perpendicular to the direction along light incident from a subject. If an eccentricity is small, values of x, γ coordinates which represent the eccentricity which are nearly zero. Data of the calculated the degree of an eccentricity is input into the controller 505 and necessity of compensation of the eccentricity is judged, based on whether the calculated degree of the eccentricity (length in the x-y plane) is more than a predetermined value or not (step S3).
As described above, the calculation section 504 in the eccentricity compensation apparatus 520 calculates the degree of an eccentricity based on photographic image data stored in the buffer memory 134 in the embodiment. However, the present invention is not limited to this form and the embodiment described above may employ another form in which an image data processing section such as white balance compensation and γ compensation by a white balance and γ processing section 133 plays a role of the above calculation section 504 to calculate the degree of an eccentricity and the calculated the degree of an eccentricity is input into the controller 505 in the eccentricity compensation apparatus 520. Also, the embodiment described above may employ a calculation section which calculates the degree of an eccentricity based on photographic image data which is immediately after being converted from an analog signal into a digital signal and before being stored in the buffer memory 134, instead of photographic image data stored in the buffer memory 134. Also, the embodiment described above may employ a calculation section which calculates the degree of an eccentricity based on photographic image data after compression process or live view data instead of photographic image data.
In the case that it is judged that it is not necessary to compensate for an eccentricity (step S3; No), the check of an eccentricity of a lens of the digital camera is completed. In the case that it is judged that it is necessary to compensate for an eccentricity (step S3; Yes), determinations of which pair of electrodes of the four pairs of electrodes of the polymer actuators 500 in
It is necessary to fix the compensation lens 20 on the position where compensation for an eccentricity is carried out in order to keep the compensation lens 20 at this position after stopping application of a voltage to the polymer actuator 500. For this purpose, there is mounted a fixing section which fixes the compensation lens 20 on the position. After the compensation lens 20 is moved to the position to compensate for an eccentricity, an operation of fixing the compensation lens 20 on the position by using the fixing section (step S6) is performed.
In
After completion of the fixing, application of a voltage is stopped. Hereafter, the polymer actuator is not necessary any more as an actuator, but useful as a damper due to its elasticity like rubber against impact on the digital camera from outside when the image taking system is used. As a result, the polymer actuator produces an effect to reduce the damage of the compensation lens originated from the impact.
The description of the thirteenth embodiment of the present invention is completed above.
As described above, an eccentricity of this digital camera is compensated by driving the compensation lens 20 with the mechanism which is simpler than that of a conventional small camera. Moreover, the polymer actuator is so cheap that it is possible to realize cost reduction for a mechanism to compensate for an eccentricity.
In the thirteenth embodiment, the object in which an eccentricity is compensated for is a digital camera. However, the present invention is not limited to this, the embodiment described above may employ a photographic unit such as a photographic unit mounted with a portable phone as the object in which an eccentricity is compensated. In this case, it is possible to use a USB terminal mounted on the photographic unit as a substitute for the camera side connector 510a for compensation for an eccentricity shown in
In the thirteenth embodiment, the compensation lens 20 is connected with the polymer actuator 500 via the holder 506. However, the present invention is not limited to this method and the embodiment described above may employ another method in which a transparent dielectric elastomer that light easily runs through is used to connect the compensation lens 20 directly with the polymer actuator 500 without using the holder 506. Except this point, an external view, a structure and a mechanism to compensate for an eccentricity of an image taking apparatus in such an embodiment are the same as those of the image taking apparatus in the thirteenth embodiment. Thus, the same description which has been already made will be omitted. In the thirteenth embodiment the compensation lens 20 is fixed on the position to compensate for an eccentricity by fixing the both ends of the compensation lens 20. But it is possible to employ another fixing method in which UV solidifying material which is solidified under ultraviolet rays radiation is used. In this fixing method, the UV solidifying material is mixed with the dielectric elastomer 501′ in
In the thirteenth and fourteenth embodiments, the compensation lens 20 is a single lens. However, the present invention is not limited to this type and the embodiment described above may employ a combination lens to compensate for an eccentricity as described in
In the thirteenth to fifteenth embodiments described above, the external frame 507 to fix the polymer actuator has a square cross section with respect to the plane which is perpendicular to the direction along light incident from a subject. However, the present invention is not limited to this shape and the embodiments described above may employ an external frame whose cross section is circular as described in
In the thirteenth to sixteenth embodiments described above, the voltages to be supplied to the four pairs of electrodes is adjusted via adjustment of the values of the voltages. However, the present invention is not limited to this adjustment method and the embodiments described above may employ another adjustment method as described in
In the thirteenth to seventeenth embodiments, an eccentricity is compensated by application of a voltage of a value which corresponds to the eccentricity. It is possible to employ another method in which an eccentricity is compensated for by release of a voltage of a value which corresponds to the eccentricity. Description of such an embodiment will be made below as the twelfth embodiment.
An external view and a structure of an image taking apparatus in the eighteenth embodiment are the same as those of the image taking apparatus in the thirteenth embodiment. Thus, the same description which has been already made above is omitted. In the eighteenth embodiment, voltages are applied to the polymer actuator before an eccentricity is compensated for. When necessity of compensation of an eccentricity is recognized, an appropriate pair of electrodes which corresponds to the degree of the eccentricity is selected and a voltage supplied to the pair of electrodes is released. The dielectric elastomer which expands before the release of a voltage contracts by this release. The compensation lens is driven by the contraction of the polymer actuator and the eccentricity is compensated for.
Next, embodiments of the fifth camera shake compensation unit and the fifth image taking apparatus according to the present invention will be described below.
In the following description, a digital camera is employed as an example of the fifth image taking apparatus according to the present invention. An external view of the digital camera is the same as that of the digital camera in
The digital camera has the polymer actuator 2500 to move the CCD 40. The polymer actuator 2500 has a shape of a square with a square hole on its center by which a square holder 2506 is surrounded. Also, around the polymer actuator 2500, an external frame 2507 which fixes the external ends of the polymer actuator 2500. A combination of the CCD 40 and the holder 2506 is an example of the image taking device according to the present invention, and the external frame 2507 is an example of the holding member.
The polymer actuator 2500 includes eight electrodes 2502a, 2502b, 2502c, 2502d, 2502a′, 2502b′, 2502c′, 2502d′ on the upper side and four electrodes (only two electrodes 502_1, 502_2 are shown) on the lower side in addition to the same dielectric elastomer 501 as that of the first embodiment. Each of electrodes 2502a, 2502b, 2502c, 2502d, 2502a′, 2502b′, 2502c′, 2502d′ on the upper side and of four electrodes on the lower side is made of carbon fiber with high conductivity and is put on the dielectric elastomer 501. The eight electrodes 2502a, 2502b, 2502c, 2502d, 2502a′, 2502b′, 2502c′, 2502d′ on the upper side are anodes and the four electrodes on the lower side are cathodes. Two of the eight anodes on the upper side are positioned opposite to each of the four cathodes on the lower side with the dielectric elastomer 501 between them. That is, they constitute four pairs of electrodes in which two anodes on the upper side and a cathode on the lower side consist in one pair. These four pairs of electrodes are respectively connected with an anode and a cathode of the power which is not shown in
The dielectric elastomer 501 has a shape of a square with a square hole on its center by which the square holder 2506 is surrounded. A part of the dielectric elastomer 501 which is not covered with the eight electrodes 2502a, 2502b, 2502c, 2502d, 2502a′, 2502b′, 2502c′, 2502d′ appears in
The above structure of the polymer actuator 2500 makes it possible to apply voltages of different values to the eight parts of the dielectric elastomer 501 sandwiched between the eight electrodes on the upper side and the four electrodes on the lower side. Then a mechanism to apply voltages with different values to the eight parts will be described below. Description of a part of the dielectric elastomer 501 sandwiched between the upper electrodes 2502a, 2502b on this side and the lower electrode 502_1 below them will be described below as an example.
As shown in
Incidentally, voltages are supplied by the power 102 in the embodiment. However, it may be possible to use high voltage supplied to the flash emission section 12.
Next, description of a state in which a voltage is applied to the dielectric elastomer 501 will be made below. In the following description, the case in which a voltage is applied to a part of the dielectric elastomer 501 sandwiched between the left electrodes 2502a of the two electrodes 2502a, 2502b on the upper side and the electrode 502_1 on the lower side will described as an example.
When the mobile terminals 5032a is moved to a upper position than that of the mobile terminals 5032a in
The same mechanism as the above is mounted for each of the four pairs of electrodes described in
Description of how to compensate for a camera shake which causes a shift and rotation of a subject image will be described. For compensation of such a camera shake, the mechanism described above is used in order to rotate and shift the CCD 40 on the plane which is perpendicular to the direction along light incident from a subject.
When no voltages are applied between the eight anode electrodes 2502a, 2502b, 2502c, 2502d, 2502a′, 2502b′, 2502c′, 2502d′ and four cathode electrodes (not shown), the state shown in
When a camera shake occurs and the camera shake detection section 450 in
Description of how the CCD 40 is driven will be made in detail below. In the following description, compensation for a camera shake which causes rotation of a subject image, not a shift of a subject image will be described first. Then compensation for a camera shake which causes both rotation and a shift of a subject image will be described.
First, compensation for a camera shake which causes rotation of a subject image will be described.
Description will be made below, as an example, on the supposition that it is required that the CCD 40 is rotated clockwise in the direction of light incident from a subject from its position shown in
A part of the dielectric elastomer 501 near the electrode 2502a which are on the left-lower position of the CCD 40 expands in the direction of arrows A1, A2, A3 in
The description of compensation of a camera shake which causes rotation of a subject image is completed above.
Next, description of compensation of a camera shake which causes both rotation and a shift of a subject image will be made. Such a camera shake can be compensated for by rotating and shifting the CCD 40 on the plane which is perpendicular to the direction along light incident from a subject. In the following description, the case in which the CCD 40 is rotated clockwise in the direction of light incident from a subject and shifted upward by using the electrode 2502a on the left-lower position of the CCD 40 and the electrode 2502b′ on the right-upper position of the CCD 40 as described above will be described as an example.
In order to realize a shift of the CCD 40, it is necessary for generating the two kinds of expansion force to act on the CCD 40 that the upward expansion force is larger than the downward expansion force. Therefore, the applied voltages are controlled in order that the voltage supplied to the electrode 2502a on the left-lower position of the CCD 40 is larger than the voltage supplied to the electrode 2502b′ on the right-upper position of the CCD 40.
The part of the dielectric elastomer 501 near the electrode 2502a which are on the left-lower position of the CCD 40 expands in the direction of arrows A1′, A2′, A3′ in
The description of compensation of a camera shake which causes both rotation and a shift of a subject image is completed above.
In the above description, a camera shake which causes at least rotation of a subject image is described. However, a camera shake which causes only a shift of a subject image is also compensated for by shifting the CCD 40 without rotating using the above structure. The shift of the CCD 40 is realized by supplying voltages of the same value to two anode electrodes which belong to the same pair of electrodes. For example, the CCD 40 is shifted upward without rotating by supplying voltages of the same value to the left electrode 2502a and the right electrode 2502b of the two electrodes on this side of
The description of the nineteenth embodiment is completed above.
As described above, a camera shake of the digital camera is compensated by driving the CCD 40 with the mechanism which is simpler than a conventional mechanism. Moreover, the polymer actuator to drive the CCD 40 is so cheap that the mechanism is appropriate to realize reduction in size and cost of a digital camera.
Compensation of a camera shake which causes both rotation and a shift of a subject image is carried out in the nineteenth embodiment. However, a mechanism which can compensate for only a camera shake which causes rotation of a subject image is useful enough when image taking is carried out in a situation that a camera shake mainly causes rotation of a subject image, not a shift of a subject image. Description of such an embodiment will be made below as the twentieth embodiment. In the twentieth embodiment, a different type of closed electric circuit from that in
In the twentieth embodiment, there is mounted only one voltage adjustment section 2503A which corresponds to a closed electric circuit which has the two electrodes 2502a, 2502b on the upper side and the electrode 502_1 on the lower side of the polymer actuator 2500. By this structure, there is a relative difference between two voltages to control, that is, a voltage applied between the left anode electrodes 2502a and the cathode electrode 502_1, and a voltage applied between the right anode electrodes 2502b and the cathode electrode 502_1. The sum of the two voltages is always constant (the same as the supply voltage of the power 102).
There is such a structure for each of the four pairs of electrodes described in
In the nineteenth embodiment described above, the voltages to drive the polymer actuator is adjusted via adjustment of the values of the voltages. However, the present invention is not limited to this adjustment method and the embodiments described above may employ another adjustment method, for example, a so-called PWM control method in which adjustment of time intervals when a voltage is applied is carried out in order to control drive of the CCD although voltage application has only two stages of On and Off. Description of such an embodiment will be made below as the twenty-first embodiment.
As shown in
Incidentally, the method of controlling the pulse width of the applied voltage which consists of a series of square-wave pulse voltages is employed in order to control the effective voltage in the twenty-first embodiment. However, the present invention is not limited to this method and the embodiment described above may employ another method in which voltage is controlled by controlling a period of an applied voltage which consists of a series of square-wave pulse voltages.
Turning on and off of voltage application to the polymer actuator is carried out by the two switches which is mounted in each of the four pairs of electrodes in the twenty-first embodiment. However, the present invention is not limited to this and the embodiment may employ a circuit element such as a thyristor and a MOS-type FES which turns on and off the electric current in order to control turning on and off of a voltage applied to the polymer actuator 2500.
Incidentally, voltages are supplied by the power 102 in the twenty-first embodiment. However, it may be possible to use high voltage supplied to the flash emission section 12.
Except a point that the CCD is driven under the control of the pulse width of a series of square-wave pulse voltages generated by the voltage application of two stages of On and Off, an external view, a structure and a mechanism to compensate for a camera shake of an image taking apparatus in the twenty-first embodiment are the same as those of the image taking apparatus in the nineteenth embodiment. Thus, the same description which has been already made above is omitted.
In the nineteenth to twenty-first embodiments described above, the external frame 2507 to fix the polymer actuator has a square cross section with respect to the plane which is perpendicular to the direction along light incident from a subject. However, the present invention is not limited to this shape and the embodiments described above may employ an external frame whose cross section is circular. Description of such an embodiment will be made below as the Twenty-second embodiment.
Four pairs of electrodes in which two anodes and a cathode consist in one pair are mounted in the twenty-second embodiment in the same way as the case shown in
In the nineteenth embodiment, a camera shake is compensated for by application of a voltage of a value which corresponds to the detected camera shake. It is possible to employ another method in which a camera shake is compensated for by release of a voltage of a value which corresponds to the detected camera shake. Description of such an embodiment will be made below as the twenty-third embodiment.
An external view and a structure of an image taking apparatus in the twenty-third embodiment are the same as those of the image taking apparatus in the nineteenth embodiment. Thus, the same description which has been already made above is omitted. In the twenty-third embodiment, voltages are applied to the polymer actuator before a camera shake is detected. When a camera shake is detected, an appropriate pair of electrodes which corresponds to the detected camera shake is selected and a voltage supplied to the pair of electrodes is released. The dielectric elastomer which expands before the release of a voltage contracts by this release. The CCD is driven by the contraction of the polymer actuator and the camera shake is compensated.
The description of the embodiments of the present invention is completed above.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-334188 | Nov 2005 | JP | national |
| 2005-349191 | Dec 2005 | JP | national |
| 2005-349195 | Dec 2005 | JP | national |
