JP4116185B2 - Imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus, and more particularly to a technique for preventing camera shake when imaging using a digital camera or the like.
[0002]
[Prior art]
In the invention of Japanese Patent Application Laid-Open No. 64-78581 (image blur correction device for video camera), an electromechanical conversion element is used, and image blur is prevented by driving the image sensor in accordance with camera shake. However, a mechanism for mechanically driving the image sensor is not described.
[0003]
In the invention of Japanese Patent Laid-Open No. 2-103023 (video camera), image blurring is prevented by enabling the image sensor to move along a plane perpendicular to the optical axis. However, since the mechanism for mechanically driving the image sensor is a large-scale device such as a motor and a drive base, it is not suitable for downsizing and high-speed response.
[0004]
In the invention of Japanese Patent Laid-Open No. 6-46322 (photographing apparatus with an image stabilization function and an interchangeable lens), image blurring is prevented by moving a photoelectric conversion element based on camera shake. However, since the mechanism for mechanically driving the image sensor is complicated, it is not suitable for downsizing and cost reduction.
[0005]
In the invention of Japanese Patent Application Laid-Open No. 10-145663 (electronic camera), movement is detected, and the image pickup device moving means is driven accordingly to prevent camera shake. However, since the mechanism for mechanically driving the image sensor is complicated, it is not suitable for downsizing and cost reduction.
[0006]
[Problems to be solved by the invention]
As described above, in recent years, digital cameras have begun to spread widely from business to personal use. However, in the future, blurring of images due to camera shake at the time of shooting will be a major problem. The reason is as follows.
(1) Due to demands from users, digital cameras are becoming smaller and lighter. However, since a small but low-sensitivity CCD is adopted, the camera shake becomes conspicuous because the exposure time increases.
(2) Due to the use of a liquid crystal finder or the like, there has been an increase in those not equipped with an optical finder such as a silver salt camera. For this reason, a shooting style such as moving the digital camera away from the body or holding it with one hand has arisen, and stability during shooting is reduced.
(3) Due to differentiation from other companies' products, etc., it is expected that a lens equipped with a high-power zoom lens will appear, and camera shake is conspicuous due to the high-power lens.
[0007]
In a video camera, a method of suppressing image blur by detecting camera shake from shaking of an image and controlling an image area cut out from a field memory according to the amount of movement is described in, for example, the Journal of Television Society, Vol. 2, PP. 131-134 (1995). However, this method cannot be used because image blur due to camera shake in a digital camera (digital still camera) is caused by camera shake within the capture time of one frame. This is because the above-described method used in a video camera corrects a shift between frames, and does not consider camera shake during capturing one frame. Therefore, as a method that can also be applied to a digital camera, an image with less blur can be obtained by moving the optical axis in accordance with the movement of the camera due to camera shake using a parallel movement with respect to the optical axis of the lens or a variable apex angle prism. is there. However, these correction mechanisms have the problem of increasing the size and weight of the digital camera itself, and are not suitable for popular machines.
[0008]
On the other hand, in order to solve the above-mentioned problems, the method of moving only the image pickup element according to the hand shake by a piezoelectric element or the like is disclosed in the above-mentioned JP-A 64-78581, JP-A-2-103030, 6-46322, JP-A-10-145663, and the like. However, the inventions described in these publications do not describe moving means of the image sensor or are too large to be mounted on a small digital camera, and are too complicated and expensive.
[0009]
In view of the problems described above, intended to prevent image blur due to shake of the digital camera by realizing the parallel movement of the image sensor in a simple and compact mechanism, a first aspect of the invention, the image pickup element 2 3. The image pickup device can be translated by a simple and small mechanism by being directly connected to a piezoelectric actuator using a single leaf spring , and a camera shake prevention mechanism can be mounted on a digital camera. is an imaging element, by Rukoto using each stretchable two electromechanical transducer means in two directions not identical, the imaging element in two directions perpendicular can be moved parallel in a simple and compact mechanism, digital camera The invention according to claim 3 makes it possible to mount two electromechanical transducers with an L-shaped joining member with a simple configuration. By constructing a biaxial camera shake prevention mechanism for the digital camera, the invention of claim 4 enables the curvature of the leaf spring to be adjusted, so that an image sensor at a fixed position that does not displace the piezoelectric element can be arbitrarily set. It was made for the purpose of adjusting the position .
[0010]
[Means for Solving the Problems]
The invention of claim 1 is an imaging apparatus having an imaging optical system and an imaging element that receives a subject image that has passed through the imaging optical system and converts it into an image signal, and is parallel to one side of the imaging surface of the imaging element. An applied voltage is obtained by disposing a restraining plate at both ends in the stretching direction of the piezoelectric element having the stretching direction set so as to be fixed, and fixing two leaf springs with the piezoelectric element sandwiched between the restraining plates. Electromechanical conversion provided with a displacement amount expansion mechanism that expands a displacement amount due to expansion and contraction of the piezoelectric element according to the above as a displacement amount of the leaf spring in a direction orthogonal to the expansion and contraction direction of the piezoelectric element within the imaging surface of the imaging element And the electromechanical conversion means and the image pickup device are connected, and the image pickup device is displaced within the image pickup surface by expansion and contraction of the piezoelectric element , and the image pickup device is directly connected to the piezoelectric actuator. Do And it allows simple and can be moved in parallel to the imaging element in a compact mechanism is obtained by allowing the image stabilizing mechanism mounted to the digital camera.
[0011]
According to a second aspect of the present invention, in the first aspect of the invention, the electromechanical conversion unit includes two electromechanical conversion units, and the first electromechanical conversion unit displaces the imaging element in a direction parallel to one side thereof. The image sensor is displaced in another direction orthogonal to the direction by the electromechanical conversion means , and the image sensor is directly connected to two piezoelectric actuators that can be expanded and contracted in two different directions. Thus, the image sensor can be translated in two orthogonal directions with a simple and small mechanism, and a two-axis camera shake prevention mechanism can be mounted on the digital camera.
[0012]
The invention according to claim 3 is the invention according to claim 2 , wherein one spring of the second electromechanical conversion means is connected to a portion fixed to the imaging device main body, and the other spring of the second electromechanical conversion means is , Connecting to one arm of the L-shaped joining member, connecting the other arm of the joining member to one spring of the first electromechanical conversion means, and connecting the other spring of the first electromechanical conversion means It is characterized in that it is connected to one side of the image pickup surface of the image pickup device, so that each of the two electromechanical conversion means individually bears displacement in two directions of the image pickup device .
[0013]
The invention of claim 4 is characterized in that, in the invention of any one of claims 1 to 3, a holding screw for adjusting the curvature of the leaf spring is provided at one end in the expansion / contraction direction of the piezoelectric element. The amount of displacement of the leaf spring at the fixed position can be adjusted, and the image sensor can be set at an arbitrary position .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram illustrating a configuration of a camera shake correction unit of an imaging apparatus to which the present invention is applied. The camera shake amount is detected by one or more camera shake detection sensors 11 attached to the imaging apparatus body. This camera shake detection sensor is configured by any one of a gyroscope, an acceleration sensor, a magnetic direction sensor, and an image sensor, or a combination thereof. Various filters and amplifier circuits are also included in this. The camera shake signal from the camera shake detection sensor 11 is input to the camera movement amount calculation unit 13 via the A / D conversion unit 12. The camera movement amount calculation unit 13 calculates part or all of movement amounts such as a posture change amount and a translational change amount due to camera shake of the imaging apparatus. Next, using the calculation result of the camera movement amount calculation unit 13, the image pickup device (actuator) movement amount calculation unit 14 calculates the movement amount of the image pickup element for canceling the movement of the image due to camera shake. Next, the image sensor movement amount signal is sent to a booster circuit 15 accompanied by D / A conversion means. The booster circuit 15 supplies a voltage for driving the piezoelectric actuator 16 so that the piezoelectric actuator 16 generates a displacement corresponding to the moving amount of the image sensor. One or two booster circuits 15 and piezoelectric actuators 16 are used. The camera movement amount calculation unit 13 and the image sensor movement amount calculation means 14 are configured by a microcomputer, a peripheral circuit, and software, but other methods may be used. The above-described configuration, that is, camera shake is detected, and the image sensor is moved accordingly, thereby suppressing image blur due to camera shake.
[0016]
FIG. 2 is a main part configuration diagram for explaining an example of the moving method of the image pickup device, and the image pickup device 21 in the image pickup apparatus is fixed to the substrate 22. One end of the piezoelectric actuator 23 is connected to one side of the substrate 22. Although not shown, the other end of the piezoelectric actuator 23 is bonded to a portion fixed to the image pickup apparatus main body. The piezoelectric actuator 23 expands and contracts in the direction of arrow A in the figure. Due to the displacement of the piezoelectric actuator 23, the image pickup device 21 is displaced with respect to the image pickup apparatus body. The piezoelectric actuator 23 is arranged so that this displacement is in the imaging plane. As a result, the image sensor can be displaced so as to cancel camera shake in a certain direction. Although the piezoelectric actuator 23 is shown as a piezoelectric element itself , the present invention is characterized in that an expansion mechanism for expanding the displacement amount is added to the piezoelectric element .
[0017]
FIG. 3 is a view showing an embodiment of a piezoelectric actuator composed of the above-described piezoelectric element with an enlargement mechanism, and a pressing plate 33 is bonded to one end of the piezoelectric element 31. A holding plate 32 is also arranged at the other end, and two leaf springs 34 and 35 are fixed between the holding plates 32 and 33. The curvature of the leaf spring at the time of fixation is adjusted with a set screw 36. When a voltage is applied to the piezoelectric element 31, the piezoelectric element 31 extends in the directions indicated by A and A '. As a result, displacements indicated by B and B ′ occur in the leaf springs 34 and 35. As shown in FIG. 4, the image pickup element 21 or the substrate 22 to which the image pickup element 21 is fixed is bonded to one of the leaf springs of the piezoelectric actuator 41 configured as described above, and the other is fixed to the image pickup apparatus main body. Adhere to.
[0018]
Figure 5 is a main part configuration diagram for explaining one embodiment of the invention of claim 2, in the configuration described in the embodiment, the piezoelectric actuator 41 having a displacement of expansion mechanism with respect to the imaging device body The one end adhered to the fixed portion is adhered to the joining member 51 without being adhered to the imaging apparatus main body. The bonding member 51 is further bonded and held on another piezoelectric actuator 42. One end of the piezoelectric actuator 42 is bonded to the bonding member 51, and the other end is bonded to a portion fixed to the image pickup apparatus main body. The piezoelectric actuator 41 and the piezoelectric actuator 42 are arranged so that their displacement directions are not the same and are within the imaging surface. Thereby, the image sensor 21 can be displaced in any direction within the same plane. As a result, the image sensor can be displaced so as to prevent blurring of front, back, left and right when viewed on the image plane. Further, the shape of the joining member 51 is not limited to that shown in FIG. 5, and any shape that can join the piezoelectric actuator 41 and the piezoelectric actuator 42 may be used.
[0019]
In the first and second aspects of the invention, it has been described that the image sensor is displaced within the imaging surface. However, the image quality may be deviated from the surface within an allowable range depending on the accuracy of assembly. .
[0020]
Figure 6 is a main part configuration diagram for explaining a preferred variant of the present invention, the force generating device 61, such as a server Ne, connected to the junction member 51, substantially opposite direction of the force and displacement direction of the image pickup device 21 Add Thereby, it can suppress that the displacement of the piezoelectric actuators 41 and 42 is not correctly transmitted to an image pick-up element, when the joining member 51 vibrates. Here, two force generation devices are used, but one or three or more force generation devices may be used.
[0021]
7 is a main part configuration diagram for illustrating another modification of the present invention, the friction force generating device 71, in which to be connected to the imaging device 21 or the substrate 22. Thereby, damping of the image sensor and rotation around the optical axis can be suppressed during camera shake correction. Here, although the number of frictional force generating devices is two, one or three or more may be used.
[0022]
Figure 8 is a further view essential structure for explaining another modification of the present invention, the force generating device 81 due to server Ne, and connected to the imaging device 21 or the substrate 22, the piezoelectric actuator 41 is free The image pickup device 21 can be held at a predetermined position against vibration or the like when energized (when stationary). As a result, when the piezoelectric actuator has a displacement enlargement mechanism using a spring, the initial state of the spring at rest can be set so that the spring has a desired displacement at the time of camera shake correction. Here, two force generation devices are used, but one or three or more force generation devices may be used.
[0023]
【The invention's effect】
Effect of Claim 1 By directly connecting an image pickup device to a piezoelectric actuator, it is possible to provide a digital camera equipped with a camera shake prevention mechanism in which the image pickup device can be translated in a simple and small mechanism.
[0024]
Advantages of Claim 2 By using conversion means for two electrical naturalizations that can expand and contract the image sensor in two directions that are not the same, the image sensor can be translated in two directions that are orthogonal with a simple and small mechanism. A digital camera equipped with an anti-shake mechanism can be provided.
[0025]
Effect on claim 3
Since it is connected to the image sensor through the second electromechanical conversion means, the joining member, and the first electromechanical conversion means from the portion fixed to the image pickup apparatus main body, the image sensor 2 is connected by each electromechanical conversion means. It can be displaced dimensionally. Thereby, it is possible to provide a digital camera equipped with a more accurate camera shake prevention mechanism.
[0026]
Effect on claim 4
By making it possible to adjust the curvature of the leaf spring, it is possible to adjust the imaging element at a fixed position that does not give displacement to the piezoelectric element so as to be at an arbitrary position . Thereby, it is possible to provide a digital camera equipped with a more accurate camera shake prevention mechanism.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a camera shake correction unit of an imaging apparatus to which the present invention is applied.
FIG. 2 is a main part configuration diagram for explaining an example of an image sensor moving method ;
FIG. 3 is a view showing an embodiment of a piezoelectric actuator composed of a piezoelectric element with an enlargement mechanism.
FIG. 4 is a diagram illustrating an example in which an imaging device is attached to a piezoelectric actuator.
FIG. 5 is a main part configuration diagram for explaining an embodiment of the invention of claim 2;
FIG. 6 is a main part configuration diagram for explaining a preferred modification of the present invention .
FIG. 7 is a main part configuration diagram for explaining another modified example of the present invention .
FIG. 8 is a main part configuration diagram for explaining still another modified example of the present invention .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Camera shake detection sensor, 12 ... A / D conversion means, 13 ... Camera movement amount calculation part, 14 ... Imaging element movement amount calculation part, 15 ... Booster circuit, 16 ... Piezoelectric actuator, 21 ... Imaging element, 22 ... Board | substrate, DESCRIPTION OF SYMBOLS 23 ... Voltage actuator, 31 ... Voltage element, 32, 33 ... Holding plate, 34, 35 ... Leaf spring, 36 ... Holding screw, 41, 42 ... Piezoelectric actuator, 51 ... Joining member, 61 ... Force generator, 71 ... Friction Force generator, 81... Force generator.

Claims (4)

In an imaging apparatus having an imaging optical system and an imaging element that receives a subject image that has passed through the imaging optical system and converts it into an image signal , the expansion / contraction direction is set to be parallel to one side of the imaging surface of the imaging element By disposing a restraining plate at both ends in the expansion / contraction direction of the piezoelectric element, and fixing two leaf springs with the piezoelectric element sandwiched between the suppression plates, the expansion / contraction of the piezoelectric element according to the applied voltage is achieved. Electromechanical conversion means including a displacement amount enlargement mechanism that expands the displacement amount due to the displacement amount of the leaf spring in a direction orthogonal to the expansion / contraction direction of the piezoelectric element within the imaging surface of the imaging element, An image pickup apparatus with a shake prevention function, wherein a mechanical conversion unit and the image pickup element are connected, and the image pickup element is displaced within an image pickup surface by expansion and contraction of the piezoelectric element . There are two electromechanical conversion means, the first electromechanical conversion means displaces the imaging element in a direction parallel to one side thereof, and the second electromechanical conversion means causes the imaging element to be orthogonal to the direction. The image pickup apparatus with a shake prevention function according to claim 1, wherein the image pickup apparatus is displaced in the direction of . One spring of the second electromechanical conversion means is connected to a portion fixed to the imaging apparatus body, and the other spring of the second electromechanical conversion means is connected to one arm of the L-shaped joining member, The other arm of the joining member is connected to one spring of the first electromechanical conversion means, and the other spring of the first electromechanical conversion means is connected to one side of the imaging surface of the imaging element. The imaging apparatus with a shake prevention function according to claim 2. The expansion and contraction direction of the one end of the piezoelectric element, the imaging equipment with image stabilization function according to any one of claims 1 to 3, further comprising a restraining screws for adjusting the curvature of the leaf spring.

Images