JP4130761B2 - Electronic camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic camera that obtains an image signal by forming an image of a subject on an image sensor with a photographing lens.
[0002]
[Prior art]
In recent years, electronic cameras of a type that obtain an image signal by forming an image on, for example, a CCD image pickup device are rapidly spreading, instead of a conventional type of camera that takes a photograph on a conventional silver salt photographic film. In the case of this electronic camera as well, the image pickup device itself is the same as that of a conventional type camera, and the photographing lens (or the lens for adjusting the focus constituting the photographing lens) is moved in the optical axis direction for zoom adjustment, or zoom photography. 2. Description of the Related Art An electronic camera that has a lens and moves a photographing lens in the optical axis direction for zooming is known (see, for example, Patent Document 1 and Patent Document 2).
[0003]
In addition, an electronic camera equipped with a retractable shooting lens that retracts the shooting lens in consideration of portability when not shooting and extends the shooting lens to a position suitable for predetermined shooting when shooting is also known. In the case of an electronic camera equipped with a photographing lens, when the retracting lens is retracted, the retracting of the photographing lens greatly leads to a further reduction in the thickness of the electronic camera.
[0004]
[Patent Document 1]
JP-A-8-101333 [Patent Document 2]
Japanese Patent Laid-Open No. 10-161001 [Patent Document 3]
Japanese Patent Laid-Open No. 11-243187
[Problems to be solved by the invention]
By the way, in order to avoid the adhesion of dust to the imaging surface of the CCD imaging device, a completely sealed structure is employed in which the front surface is sealed with a glass plate or the like (see Patent Document 3). . In this case, although it is effective in preventing dust from adhering to the CCD image sensor, an attempt is made to design a thin electronic camera by disposing a collapsible photographing lens in front of the CCD image sensor and retracting it during photographing. In this case, the glass plate or the like disposed in front of the CCD image pickup device cannot be largely retracted, and it is difficult to further reduce the thickness.
[0006]
Although it is conceivable to attach a lens directly to the front surface of the CCD image sensor without having a cover glass, in order to form an image on the imaging surface, the lens is arranged at a position separated from the imaging surface by about the focal length of the lens. It is necessary to increase the size in the direction of the optical axis, and when the CCD image sensor is sealed, if the lens is moved in the direction of the optical axis, it will move against the air pressure in the sealed space, requiring a large drive. Become. On the other hand, if air holes are formed to avoid this, dust may enter from the air holes together with air and adhere to the imaging surface.
[0007]
In view of the above circumstances, the present invention can easily move an optical member in the optical axis direction while placing an optical member such as a lens on the front surface of the image sensor and forming a sealed space between the image sensor and the optical member. An object of the present invention is to provide an electronic camera having a mechanism capable of performing the above.
[0008]
[Means for Solving the Problems]
The electronic camera of the present invention that achieves the above object is an electronic camera that obtains an image signal by forming an image of a subject on an image sensor with a photographing lens.
An optical member disposed in front of the image sensor;
A holding unit that holds the optical member so as to be movable in an optical axis direction that is in contact with and away from the imaging device, and forms a first space between the optical member and the imaging device;
A second space having a variable volume connected to the first space, forming a sealed space including the first space and the second space, and changing the volume of the second space; A drive unit that moves the optical member in the optical axis direction by injecting gas accumulated in the second space into the first space or sucking gas from the first space and collecting the gas in the second space; It is provided with.
[0009]
In the electronic camera of the present invention, a second space with a variable volume connected to the first space on the front surface of the image sensor is formed, and a sealed space including the first space and the second space is formed. The optical member is moved by the movement of gas between the second space and the second space, and since the ingress of air from the outside is prevented, the ingress of dust is prevented and the optical member is moved with a small driving force. It can be moved easily.
[0010]
Here, in the electronic camera of the present invention, the optical member may be at least one lens constituting a photographing lens.
[0011]
By forming a sealed space with the lenses constituting the photographing lens, the lens can be retracted to the maximum extent, and the focus can be adjusted by moving the lens.
[0012]
However, the optical member is not limited to the lens constituting the photographing lens. For example, a low-pass that requires a predetermined distance from the photographing surface in consideration of the possibility of dust adhering to the surface. It may be a filter, a flat glass, a wedge-shaped optical member, a lens with low power, or a combination thereof. In that case, when retracting, the optical member such as the low-pass filter is brought close to the imaging surface, so that the electronic camera having the specification in which the optical member such as the low-pass filter is disposed can be retracted to the maximum extent.
[0013]
In the electronic camera of the present invention, the holding unit may hold an optical member via a bellows and move the optical member by expansion and contraction of the bellows. Alternatively, the holding unit may include an imaging element. You may have a 1st holding member to hold | maintain, and a 2nd holding member hold | maintained so that the optical member can be slidably supported in the optical axis direction while holding an optical member.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0015]
FIG. 1 is an external perspective view of the electronic camera according to the first embodiment of the present invention as viewed obliquely from the front, and FIG. 2 is an external perspective view of the electronic camera of FIG.
[0016]
As shown in FIG. 1, a photographing lens 11 is provided at the center of the front surface of the electronic camera 10. The photographing lens 11 forms an image of an incident subject light on a photographing surface of a CCD image pickup device (not shown here) disposed therein, and an image signal representing the subject image is generated by the CCD image pickup device. Is done.
[0017]
Further, as shown in FIG. 1, the electronic camera 100 is provided with an objective window 11 of an optical finder and an auxiliary light emitting unit 13 at the upper part of the front surface thereof. Furthermore, a shutter button 14 and a slide type power switch 15 are provided on the upper surface of the electronic camera 100.
[0018]
Further, as shown in FIG. 2, an optical viewfinder eyepiece window 16, a menu switch 17, an execution / screen changeover switch 18, and an image monitor 19 are provided on the back of the electronic camera 100.
[0019]
FIG. 3 is a view showing a lens driving mechanism of the electronic camera whose appearance is shown in FIGS.
[0020]
FIG. 3 shows a holding member 22 that holds the CCD image pickup device 21 and holds the photographing lens 11 shown in FIG. 1 on the front surface of the CCD image pickup device 21.
[0021]
The holding member 22 holds the CCD image sensor 21 directly and fixedly, while the photographing lens 11 is held via the bellows 221.
[0022]
The bellows 221 expands and contracts as will be described later, and moves the photographic lens 11 in a direction (optical axis direction) in contact with and away from the CCD image pickup device 21.
[0023]
In addition, the holding member 22 forms a first space 222 between the CCD image pickup device 21 and the photographic lens 11, and the first space 222 is provided via the air passage 2221 and the tube. 31 is connected to a second volume 401 having a variable volume, which is defined by a cylinder 41 and a piston 42 that constitute the drive unit 40, via an internal space 311 of 31. The second space 401 is connected to the first space 222, but is isolated from the outside. That is, a sealed space including the first space 222 and the second space 401 is formed here.
[0024]
Further, the drive unit 40 is provided with a motor 43 that can freely rotate forward and backward. One end of an arm 44 is fixed to a rotation shaft 431 of the motor 43. When the motor 43 rotates in the forward direction and the reverse direction, the arms 44 rotate in the directions indicated by arrows A and B, respectively, and the piston 42 is pushed into the cylinder 41 and pulled out from the cylinder 41, respectively. Move.
[0025]
FIG. 3 shows a state in which the arm 44 has moved in the direction of arrow A, and the air in the second space 401 is injected into the first space 222 by an amount corresponding to the amount of movement in the direction of arrow A. The lens 11 moves in a direction away from the CCD image sensor 21.
[0026]
When the motor 43 rotates in the reverse direction and the arm 44 moves in the direction of the arrow B, the detection unit 421 fixed to the piston 42 is detected by the photoelectric sensor 45, and the detection is made so that the piston 42 does not come out of the cylinder 41. As a result, the rotation of the motor 43 is stopped.
[0027]
FIG. 4 is a diagram illustrating the state of the holding member 22 when the detection unit 421 is in the initial position detected by the optical sensor 45 in the lens driving mechanism illustrated in FIG. 3.
[0028]
When the arm 44 in FIG. 3 rotates in the direction of arrow B and moves in the direction in which the piston 42 is withdrawn from the cylinder 41, the second space 401 expands and the air in the first space 222 moves to the second space 401. As shown in FIG. 4, the first space 222 is contracted, and the photographing lens 11 comes close to the CCD image sensor.
[0029]
In this way, the photographing lens 11 can be extended forward by rotating the motor 43 shown in FIG. 3 in the forward rotation direction, and the photographing lens can be retracted by rotating the motor 43 in the reverse rotation direction. In addition, by adjusting the rotation amount of the motor 43 in a state where the photographing lens 11 is extended forward, the photographing lens can be moved for focus adjustment and placed at the in-focus position.
[0030]
FIG. 5 is a block diagram showing a circuit configuration of the camera shown in FIG.
[0031]
The camera 100 includes the photographing lens 11 and the auxiliary light emitting unit 13, the shutter / diaphragm unit 71, and the CCD image sensor 21 described above. A subject imaged on the imaging surface of the CCD image sensor 21 via the photographing lens 11 and the shutter / diaphragm 71 is converted into an analog image signal by the CCD image sensor 21. Here, the shutter unit constituting the shutter / diaphragm unit 71 suppresses the occurrence of smear due to light when an analog signal is read out from the CCD image sensor 21, but may be necessary depending on the configuration of the CCD image sensor 21. It is not a thing. Further, the diaphragm unit may be a single diaphragm or a plurality of switchable diaphragms. The auxiliary light emitting unit 13 is used as auxiliary light at low illuminance, but can emit light when necessary or forcibly other than at low illuminance.
[0032]
The camera 100 also includes an analog signal processing unit 72, an A / D unit 73, a digital signal processing unit 74, a temporary memory 75, a compression / decompression unit 76, a built-in memory (or memory card) 77, An image monitor 19 and a drive circuit 78 are provided. The CCD image pickup device 21 is driven at a timing generated by a timing generation circuit (not shown) in the drive circuit 78 and outputs an analog image signal. The drive circuit 78 also includes a drive circuit that drives the photographing lens 11, the shutter / diaphragm unit 71, the auxiliary light emitting unit 13, and the like. The analog image signal output from the CCD image sensor 21 is analog signal processed by the analog signal processing unit 72, A / D converted by the A / D unit 73, and digital signal processed by the digital signal processing unit 74. Data representing the digital signal processed signal is temporarily stored in the temporary memory 75. The data stored in the temporary memory 75 is compressed by the compression / decompression unit 76 and recorded in the built-in memory (or memory card) 77. Note that, depending on the shooting mode, the compression process may be omitted and recording may be performed directly in the built-in memory 77. The data stored in the temporary memory 75 is read out to the image monitor 19, whereby an image of the subject is displayed on the image monitor 19.
[0033]
In addition, the camera 100 is provided with a CPU 79 for controlling the entire camera 100, an operation switch group 80 including the menu switch 17 and the execution / screen changeover switch 18 described above, and a shutter button 14. The operation switch Photographing is performed by operating the group 80 to set a desired photographing state and pressing the shutter button 14.
[0034]
According to the first embodiment described above, as described with reference to FIGS. 3 and 4, the air in the second space 401 is injected into the first space 221 or the air is supplied from the first space 221. By sucking and accumulating in the second space 401, the photographing lens 11 can be moved in the optical axis direction, and when retracted, it can be retracted to a marginal position on the front surface of the CCD image sensor 21. Therefore, it is possible to configure an electronic camera that contributes to thinning when retracted and has excellent portability.
[0035]
Next, another embodiment will be described. However, only differences from the first embodiment described so far will be described below.
[0036]
FIG. 6 is a diagram showing a lens driving mechanism in the electronic camera according to the second embodiment of the present invention.
[0037]
The lens driving mechanism shown in FIG. 6 includes a first holding member 22_1 that holds the CCD image pickup device 21 and a second holding member 22_2 that holds the photographing lens 11. Here, the second holding member 22_2 holds the photographing lens 11, and an O-ring 23 is interposed between the second holding member 22_1 and the first holding member 22_1, and slides in the optical axis direction with respect to the first holding member 22_1. It is freely supported by the first holding member 22_1.
[0038]
A first space 222 is formed between the first holding member 22_1 and the second holding member 22_2, and the first space 222 is defined only by the air passage 2221 and the internal space 311 of the tube 31. The second space 401 having a variable volume formed by the cylinder 41 and the piston 42 is connected thereto. That is, also in this embodiment, a sealed space including the first space 222 and the second space 401 is formed.
[0039]
In the piston 42 shown in FIG. 6, an O-ring 46 is used at a portion in contact with the inner surface of the cylinder 41, and the second space 401 is more reliably isolated from the outside. A rack 422 is formed at the rear end of the piston 42 and is further urged in the direction of arrow B by a tension spring 47. In addition, a potentiometer 48 is provided here, and a pinion 49 that meshes with the rack 422 of the piston 42 is fixed to the rotating shaft 481 of the potentiometer 48.
[0040]
When the potentiometer 48 is operated, the piston 42 moves in the direction of arrow A via the rack-pinion mechanism to contract the second space 401, and the air in the second space 401 moves to the first space 222. The second holding member 22_2 moves forward, and accordingly, the photographing lens 11 moves forward (in the optical axis direction). When the rotation amount of the potentiometer 48 is adjusted, the position of the taking lens 11 in the optical axis direction can be adjusted accordingly. When the control signal to the potentiometer 48 is interrupted, the piston 42 moves in the direction of arrow B by the tensile force of the tension spring 47 and returns to the initial position, and the air in the first space 222 is moved to the second space 401. Accordingly, the first space 222 is shrunk, and the photographing lens is retracted in a direction approaching the CCD image pickup device 21.
[0041]
Also with the lens driving mechanism shown in FIG. 6, the photographing lens 11 can be largely retracted.
[0042]
FIG. 7 is a diagram showing a lens driving mechanism in the electronic camera according to the third embodiment of the present invention.
[0043]
The lens driving mechanism shown in FIG. 7 has the following differences as compared with the lens driving mechanism shown in FIG. That is, in the case of the lens driving mechanism shown in FIG. 3, the first space 222 and the second space 401 are connected via the air passage 2221 and the internal space of the tube 31 to form a sealed space as a whole. In contrast, in the case of the lens driving mechanism shown in FIG. 7, the sealed space is formed only by the first space 222 and the second space 401.
[0044]
Thus, in the present invention, the sealed space may be formed only by the first space and the second space, or the sealed space is formed including a space other than the first space and the second space. May be. That is, in the present invention, it is only necessary to form a sealed space including the first space and the second space.
[0045]
The other elements of the lens driving mechanism shown in FIG. 7 are the same as those of the lens driving mechanism shown in FIG. 3, and further description of the lens driving mechanism shown in FIG. 7 is omitted.
[0046]
In the lens driving mechanism shown in FIG. 7, a step 441 is formed between the first space 222 and the second space 401, and the boundary between the first space 222 and the second space 401 is clear. However, the first space and the second space do not need to have a clear boundary, and may be an integrally formed space. Even in this case, the space between the CCD image pickup device 21 and the photographing lens 11 is referred to as a first space, and the variable volume portion is referred to as a second space.
[0047]
FIG. 8 is a view showing a photographing lens of an electronic camera according to the fourth embodiment of the present invention.
[0048]
The photographing lens 11 is a zoom lens having the same configuration as the zoom lens disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 10-161001. Here, the photographic lens 11 having this zoom lens configuration has a three-group configuration including a first group 11_1, a second group 11_2, and a third group 11_3. Regarding the third group 11_3, a lens having a structure shown in FIG. A drive mechanism is adopted. For the first group 11_1 and the second group 11_2, a conventional lens driving mechanism using a cam mechanism or the like is employed, and here, illustration and description regarding the driving mechanisms of the first group 11_1 and the second group 11_2 are omitted. .
[0049]
FIG. 9 is a diagram illustrating a state in which the photographing lens having the zoom lens configuration illustrated in FIG. 8 is retracted.
[0050]
The third group 11_3 can be brought close to just before the CCD image pickup device 21, and therefore can be retracted more than before.
[0051]
FIG. 10 is a diagram showing a photographing optical system of an electronic camera according to the fifth embodiment of the present invention.
[0052]
Here, a first holding member 22_1 that holds the CCD image pickup device 21 and a second holding member 22_2 that holds the cover glass 81 are shown. The second holding member 22_2 is configured to be slidable in the vertical direction of FIG. 10 with respect to the first holding member 22_1. The second holding member 22_2 is provided between the first holding member 22_1 and the second holding member 22_2. One space 222 is formed. Although not shown in FIG. 10, the first space 222 is connected to the second space 401 in the cylinder 41 in the same manner as in FIG. 3, FIG. 6, or FIG. .
[0053]
In the example shown in FIG. 10, the photographic lens 11 is not driven by a drive mechanism characteristic of the present invention, but is driven by a conventional general drive mechanism (not shown).
[0054]
FIG. 11 is a diagram showing a retracted state of the photographing optical system shown in FIG.
[0055]
The air in the first space 222 sandwiched between the first holding member 22_1 and the second holding member 22_2 moves to the second space 401 shown in FIG. 3, FIG. 6, or FIG. 81 approaches the CCD image sensor 21, and the photographing lens 11 is retracted to a position just before the retracted cover glass 81.
[0056]
Here, as a reason for extending the cover glass 81 as shown in FIG. 10 and FIG. 11 and performing the collapse, there is a possibility that dust may adhere to the surface of the cover glass 81. That is, in the case of the structure shown in FIGS. 10 and 11, dust is prevented from adhering to the surface of the cover glass 81 facing the CCD image sensor 21, but the cover glass 81 faces the photographing lens 11. Dust may adhere to the side surface. Even if dust adheres to this surface, if it is arranged at a position away from the CCD image pickup device 21 to some extent as shown in FIG. 10, the adhering dust is not conspicuous on the photographing screen and is temporarily covered with a cover glass. In the case where it is possible to perform shooting in a state in which 81 is very close to the CCD image pickup device 21, the adhered dust appears on the shooting screen, resulting in a significant deterioration in image quality. Therefore, in the example shown in FIGS. 10 and 11, the cover glass 81 is disposed at a position away from the CCD image pickup device 21 as shown in FIG. 10 at the time of photographing, and as shown in FIG. The cover glass 81 is also retracted.
[0057]
As shown in FIGS. 10 and 11, the optical member that is retracted and extended by the drive mechanism unique to the present invention is not limited to the lens, but is extended to a desired extension position such as a cover glass or a low-pass filter. It can be applied to general optical members in need.
[0058]
Each of the embodiments described so far is an example in which air is sealed in a sealed space. However, other gases other than air, such as nitrogen, may be sealed in the sealed space referred to in the present invention. Good.
[0059]
【The invention's effect】
As described above, according to the electronic camera of the present invention, an optical member such as a lens is disposed on the front surface of the image sensor and a sealed space is formed between the image sensor and the optical member. Can be moved easily.
[Brief description of the drawings]
FIG. 1 is a perspective view of an external appearance of an electronic camera according to a first embodiment of the present invention as viewed obliquely from above.
FIG. 2 is an external perspective view of the electronic camera of FIG.
3 is a diagram showing a lens driving mechanism of an electronic camera whose appearance is shown in FIGS. 1 and 2. FIG.
4 is a diagram showing a state of the holding member when the detection unit is in the initial position detected by the photoelectric sensor in the lens driving mechanism shown in FIG. 3. FIG.
5 is a block diagram showing a circuit configuration of the camera shown in FIG. 1. FIG.
FIG. 6 is a diagram illustrating a lens driving mechanism in an electronic camera according to a second embodiment of the present invention.
FIG. 7 is a diagram illustrating a lens driving mechanism in an electronic camera according to a third embodiment of the present invention.
FIG. 8 is a view showing a photographing lens of an electronic camera according to a fourth embodiment of the present invention.
9 is a diagram illustrating a state in which the photographing lens having the zoom lens configuration illustrated in FIG. 8 is retracted. FIG.
FIG. 10 is a diagram illustrating a photographing optical system of an electronic camera according to a fifth embodiment of the present invention.
11 is a diagram showing a retracted state of the photographing optical system shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Shooting lens 12 Objective window 13 Auxiliary light emission part 14 Shutter button 15 Power switch 16 Optical viewfinder eyepiece window 17 Menu switch 18 Execution / screen switch 19 Image monitor 21 CCD image pick-up element 22 Holding member 22_1 First holding member 22_2 Second Holding member 221 bellows 222 sealed space 2221 air passage 31 tube 311 internal passage 40 drive part 41 rotating shaft 42 piston 43 motor 44 arm 45 photoelectric sensor 46 O-ring 47 tension spring 48 potentiometer 49 pinion 81 cover glass 100 electronic camera

Claims (2)

In an electronic camera that obtains an image signal by forming an image of a subject on an image sensor with a photographing lens,
A cover glass disposed in front of the image sensor;
The cover glass, the movably held in toward or away from the optical axis direction in the imaging device, and a holding portion which forms a first space between the cover glass and the image pickup element,
A second space having a variable volume connected to the first space, forming a sealed space including the first space and the second space, and changing the volume of the second space; The cover glass can be moved in the direction of the optical axis by injecting the gas accumulated in the second space into the first space or sucking the gas from the first space and collecting it in the second space. An electronic camera comprising: a driving unit that moves the holding unit held in the optical axis direction. The holding portion includes a first holding member that holds the imaging element, and a second holding member that holds the cover glass and is supported by the first holding member so as to be slidable in the optical axis direction. The electronic camera according to claim 1, wherein the electronic camera is provided.

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