JP2004356836A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera provided with a lens barrel whose cylindrical length is freely changed between a photographing state with a relatively longer cylindrical length and a retracted state with a relatively shorter cylindrical length that reduces a length in an optical axis direction in the retracted state. <P>SOLUTION: The digital camera for forming an image of an object light onto a solid-state imaging element to generate an image signal is provided with the lens barrel whose cylindrical length is freely changed between the photographing state with a relatively longer cylindrical length and the retracted state with a relatively shorter cylindrical length, and the lens barrel is provided with; a photographing lens; and a luminous quantity control member that is in an operating state for controlling the luminous quantity of a photographing light passing through the photographing lens in the photographing state and shifts to a nonuse state while an aperture is kept to a prescribed aperture diameter and moves the solid-state imaging device to a position at which the solid-state imaging device is retracted in the aperture when the photographing state shifts to the retracted state. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a camera including a lens barrel that can freely change a tube length between a shooting state with a relatively long tube length and a storage state with a relatively short tube length.
[0002]
[Prior art]
In recent years, in addition to a conventional type of camera that takes a picture on a silver salt film, a solid-state image pickup device such as a CCD image pickup device or a MOS image pickup device is provided, and an object is imaged on the solid-state image pickup device to generate an image signal. Types of digital cameras are rapidly spreading.
[0003]
In this digital camera as well, there is a strong demand for improvement in portability as well as improvement in shooting performance. In particular, by making the focal length variable, it is possible to shoot at a desired angle of view and to be convenient for carrying. Built-in shooting lens composed of a plurality of lens groups, when not shooting, retracted in the camera housing so that the distance between the plurality of lens groups constituting the shooting lens is less than the minimum required for shooting, At the time of shooting, there is a lens barrel of a type that is extended from the camera housing so that the distance between the plurality of lens groups is a distance required for shooting (see, for example, Patent Document 1).
[0004]
A digital camera equipped with the above lens barrel is made thin by retracting the lens group, light quantity control members such as shutters and diaphragms, and solid-state image sensors as close as possible to each other on the optical axis. Is planned.
[0005]
In order to realize further reduction in thickness, a proposal has been made to retract a solid-state image sensor such as a CCD image sensor from the photographing optical axis when retracted (see, for example, Patent Document 2).
[0006]
[Patent Document 1]
JP-A-10-288873 [Patent Document 2]
Japanese Patent Laid-Open No. 2003-116028
[Problems to be solved by the invention]
However, there is a limit to reducing the thickness by retracting the objects arranged on the optical axis as close as possible, and the method of reducing the thickness by retracting the solid-state imaging device from the imaging optical axis There is a problem that a space for retracting the solid-state imaging device must be secured in the camera housing.
[0008]
In view of the above circumstances, an object of the present invention is to provide a digital camera that is devised to be thin.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a digital camera of the present invention is a digital camera for generating an image signal by forming an image of subject light on a solid-state imaging device.
A lens barrel that can freely change the tube length between a relatively long tube length shooting state and a relatively short tube length storage state,
This lens barrel
A photographing lens that forms an image of subject light on the solid-state imaging device in the photographing state;
It is placed between the photographing lens and the solid-state imaging device, and when in the photographing state, it is in a use state for controlling the amount of photographing light passing through the photographing lens, and shifts from the photographing state to the retracted state. And a light amount control member that shifts to a non-use state with the opening being opened to a predetermined opening diameter and moves the solid-state imaging device to a position in which the opening is received.
[0010]
In the digital camera of the present invention, when the lens barrel transitions from the photographing state to the retracted state, the light amount control member remains in a state where the opening is opened to a predetermined opening diameter, and the solid-state imaging device is opened. Move to the position received inside. In other words, according to the digital camera of the present invention, when the lens barrel is retracted, the solid-state image sensor can be accommodated in the opening of the light quantity control member. In addition, it is not necessary to secure a space for retracting the solid-state imaging device.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0012]
1 and 2 are external perspective views of a first embodiment of the digital camera of the present invention.
[0013]
FIG. 1 shows a retracted state of a lens barrel 100 incorporating a zoom lens of the digital camera 1 of the present embodiment, and FIG. 2 shows a state in which the lens barrel 100 of the digital camera 1 is extended. It is shown.
[0014]
The lens barrel 100 of the digital camera 1 shown in FIGS. 1 and 2 incorporates two lens groups, a first group and a second group, and the digital camera 1 has a plurality of steps determined in advance. At the zoom stage (stepwise multiple zoom magnifications), focus adjustment is performed by changing the relative distance between the lens groups.
[0015]
An auxiliary light emission window 12 and a viewfinder objective window 13 are arranged at the upper front of the digital camera 1 shown in FIGS. A shutter button 14 is disposed on the upper surface of the digital camera 1.
[0016]
A zoom operation switch is provided on the rear surface (not shown) of the digital camera 1. When one of the zoom operation switches is pressed, the lens barrel 100 is extended to the telephoto side while the button is being pressed, and the zoom operation switch is When the other of the buttons is pressed, the lens barrel 100 is moved to the wide-angle side while the button is being pressed, and the transition to the nearest step is performed after the pressing of the switch is completed.
[0017]
3 is a cross-sectional view of the lens barrel of the camera shown in FIGS. 1 and 2 in the retracted state along the optical axis S. FIG. 4 is a diagram of the same lens barrel as in FIG. 2 is a cross-sectional view along an axis S. FIG.
[0018]
In this lens barrel 100, in addition to the photographing lens 200 including the first group lens 201 and the second group lens 202, the shutter unit 222 and the photographing lens 200 disposed immediately before the second group lens 202 are photographed. A diaphragm unit 630 is also provided between the lens 200 and the CCD image pickup device 204 provided on the rear side in the optical axis direction. The retracted state shown in FIG. 3 and the maximum extended state shown in FIG. In between, it can be retracted and extended.
[0019]
Details of the retracting and feeding mechanism will be described later.
[0020]
Hereinafter, the diaphragm unit 630 disposed between the photographing lens 200 and the CCD image pickup device 400 attached to the base 401 fixed to the fixed frame 101 will be described. The aperture unit 630 is an example of a light amount control member according to the present invention.
[0021]
As shown in FIG. 4, the aperture unit 630 is attached to an aperture unit holding frame 215, and the maximum aperture during shooting is limited to a predetermined aperture diameter, thereby maintaining the shooting performance. . Further, in the retracted state, the aperture unit 630 can have an opening diameter that is wider than the opening diameter set as the maximum opening at the time of photographing. The size is such that the image sensor 400 can be received in the opening. In the digital camera 1 of the present embodiment, as shown in FIG. 3, when the lens barrel is retracted, the aperture unit 630 is in a state where the CCD image sensor is received in the opening. Thereby, the dimension of the optical axis direction in a retracted state in this embodiment can be shortened compared with the past.
[0022]
Here, the operation of the lens barrel 100 between the retracted state shown in FIG. 3 and the maximum extended state shown in FIG. 4 will be described. Hereinafter, a description will be given with reference to FIG.
[0023]
The lens barrel 100 includes a fixed frame 101 fixed to the camera body and a drive cylinder 102 that is rotatable with respect to the fixed frame. The drive cylinder 102 is rotatable with respect to the fixed frame 101, but a protrusion 102 a provided in the circumferential direction is fitted in a groove extending in the circumferential direction of the fixed frame 101. On the other hand, movement in the direction of the optical axis is prohibited. The drive cylinder 102 is provided with a gear 102b on the outer peripheral surface thereof. A drive gear (not shown) is engaged with the gear 102b, and a driving force from a motor (not shown) is transmitted through the gear 102b. The drive cylinder 102b rotates.
[0024]
The drive cylinder 102 is further provided with a key groove 102c extending in the optical axis direction. A pin-like cam follower 104 fixed to the rotationally movable cylinder 103 is provided on the fixed frame 101 in the key groove 102c. It penetrates through the provided cam groove. Therefore, when the drive cylinder 102 rotates, the cam follower 104 enters the key groove 102c, so that the rotational movement cylinder 103 also rotates together with the drive cylinder 102, and the cam follower 104 passes through the cam groove of the fixed frame 101. Therefore, it moves in the optical axis direction according to the shape of the cam groove while rotating as the drive cylinder 102 rotates.
[0025]
In addition, a rectilinear movement frame 105 is provided inside the rotational movement cylinder 103. The rectilinearly moving frame 105 is engaged with the rotationally movable cylinder 103 so as to be freely rotatable relative to the rotationally movable cylinder 103, and the rotation is prohibited by fitting into the key groove 101 a of the fixed frame 101. Therefore, the moving frame 105 moves together with the movement of the rotationally moving cylinder 103 in the optical axis direction when the rotationally movable cylinder 103 rotates in accordance with the rotation of the driving cylinder 102 and moves in the optical axis direction. . However, the rectilinear movement frame 105 is prohibited from rotating by fitting the fixed frame 101 into the key groove 101 a, and moves linearly in the optical axis direction as the rotational movement cylinder 103 moves.
[0026]
The second group lens 202 is held by a second group lens holding frame 212. The second group lens holding frame 212 has a cam follower 216 fixed to the second group lens holding frame 212. 103 and the key full 105a extending in the optical axis direction of the rectilinear movement frame 105. Therefore, the rotary cylinder 103 rotates in the optical axis direction as the drive cylinder 102 rotates. When moved, the second group lens holding frame 212, the second group lens 202 held by the second group lens holding frame 212, and the second group lens unit 260 including the shutter unit are inserted into the cam follower 216. It moves straight in the direction of the optical axis along the shape of the cam groove of the rotationally moving cylinder 103.
[0027]
Further, the lens barrel 100 is provided with a rectilinearly moving cylinder 106 that holds the first group lens 201. In the straight movement cylinder 106, a cam follower 107 fixed to the straight movement cylinder 106 enters a cam groove of the rotation movement cylinder 103, and also enters a key groove 105a of the straight movement frame 105 extending in the optical axis direction. Therefore, when the rotationally movable cylinder 103 rotates in accordance with the rotation of the drive cylinder 102 and moves in the optical axis direction, the cam follower 107 is fitted along the shape of the cam groove of the rotationally movable cylinder 103 in the optical axis direction. Go straight to.
[0028]
In this way, the feeding is performed, and the drive cylinder 102 is retracted by rotating in the reverse direction.
[0029]
A diaphragm unit 630 disposed between the photographing lens 200 and the CCD solid-state imaging device 400 is integrated with a diaphragm unit holding frame 215 that holds the diaphragm unit 630 by rotating a lead screw 214 by a driving source (not shown). Since the held nut 217 is screwed into the lead screw 214, the nut 217 moves in the optical axis direction as the lead screw 214 rotates.
[0030]
FIG. 5 is a block diagram showing a circuit configuration of the camera shown in FIG.
[0031]
The camera 1 includes the above-described photographing lens 200, shutter unit 222, aperture unit 630, and CCD image pickup device 400. A subject image formed on the CCD image sensor 400 via the photographing lens 200 or the like is converted into an analog image signal by the CCD image sensor 400. Here, the shutter unit 222 is for suppressing the occurrence of smear due to light when reading an analog signal from the CCD image sensor 400.
[0032]
Moreover, the auxiliary light emission part 130 is provided here, This auxiliary light emission part 130 light-emits auxiliary light at the time of low illumination. In addition, the auxiliary light emitting unit 130 can emit light when necessary other than low illuminance.
[0033]
The camera 1 also includes an analog signal processing unit 501, an A / D unit 502, a digital signal processing unit 503, a temporary memory 504, a compression / decompression unit 505, a built-in memory (or memory card) 506, An image monitor 507 and a drive circuit 508 are provided. The CCD image pickup device 400 is driven at a timing generated by a timing generation circuit (not shown) in the drive circuit 508, and outputs an analog image signal. The drive circuit 508 also includes a drive circuit that drives the photographing lens 200, the auxiliary light emitting unit 130, and the like. The analog image signal output from the CCD imaging device 400 is subjected to analog signal processing by the analog signal processing unit 501, A / D converted by the A / D unit 502, and digital signal processed by the digital signal processing unit 503. Data representing the digital signal processed signal is temporarily stored in temporary memory 504. The data stored in the temporary memory 504 is compressed by the compression / decompression unit 505 and recorded in the built-in memory (or memory card) 506. Depending on the shooting mode, the compression process may be omitted and the recording may be performed directly in the built-in memory 506. The data stored in the temporary memory 504 is read out to the image monitor 507, whereby an image of the subject is displayed on the image monitor 507.
[0034]
Further, the digital camera 1 is provided with a CPU 509 for controlling the entire digital camera 1, an operation switch group 510, and a shutter button 14, and the operation switch group 510 is operated to set a desired photographing state. The photograph is taken by pressing the shutter button 14.
[0035]
FIG. 6 is a perspective view schematically showing a CCD image pickup device fixed to a base disposed at the rear of the aperture unit during retraction.
[0036]
From the base 401 (see FIG. 4), an engagement rod 629 (bar-shaped forced retraction member) extending in the optical axis direction toward the aperture unit 630 is erected.
[0037]
On the other hand, the aperture unit 630 has a circular opening 631 centered on the optical axis S. The opening 631 has an opening diameter that can receive the CCD image pickup device 400 as shown in FIG. 3 when retracted. Is released.
[0038]
In addition, the aperture unit 630 includes a notch 632 that allows introduction of the engagement rod 629 on the extension line of the engagement rod 629.
[0039]
Further, the aperture unit 630 includes an actuator 633 that rotates the aperture blade (see FIG. 7) 634 around the rotation axis.
[0040]
FIGS. 7A and 7B are schematic views showing an example of the structure of the diaphragm blades provided in the diaphragm unit and the operation thereof.
[0041]
The aperture blade 634 rotates around the drive shaft 635 of the actuator 633 between the open position shown in FIG. 7A, that is, the retracted position, and the small aperture position shown in FIG. It is configured to move freely.
[0042]
The drive shaft 635 of the actuator 633 is spring-biased so as to move the diaphragm blade 634 to the non-retracted position in FIG. 7B. When energized, the diaphragm blade 634 is opened as shown in FIG. 7A. When the power is cut off, the diaphragm blade 634 is moved again to the non-retracted position shown in FIG.
[0043]
The aperture blade 634 retracts to the side of the aperture 631 of the aperture unit 630 when opened, and does not interfere with the aperture 631, but at the small aperture position (non-retracted position), a plate portion 634a having a size capable of shielding the aperture 631 is provided. A small hole 636 that allows light to pass therethrough is formed at the center of the plate portion 634a.
[0044]
Here, when the lens barrel 100 is in the extended state (see FIG. 4), the aperture unit 630 is in a use state for controlling the amount of photographing light passing through the photographing lens 200. When the object scene is relatively dark, the blade 634 moves to the open position retracted beside the opening 631 as shown in FIG. 7A. When the object scene is relatively bright, the blade 634 overlaps the opening 631. Move to the aperture position (non-retracted position). On the other hand, when the lens barrel 100 is in the retracted state (see FIG. 3), the aperture unit 630 is in the retracted state with the aperture blades 634 moved to the open position (retracted position).
[0045]
The end of the diaphragm blade 634 on the opposite side of the plate portion 634a does not interfere with the notch 632 of the diaphragm unit 630 when opened, but moves to a position overlapping the notch 632 when the diaphragm is small, and is notched during retraction. A cam portion 634 b that interferes with the engagement rod 629 entering the 632 is provided.
[0046]
Here, as shown in FIG. 6, the engagement rod 629 has a tapered portion 629 a at the tip portion thereof, and this engagement rod 629 enters the notch 632 when retracted. When the aperture spring 634 is in the small aperture state shown in FIG. 7B, the cam portion 634 b of the aperture blade 634 is pushed by the taper portion 629 a, and the cam portion 634 b is connected to the drive shaft 635 of the actuator 633. 7B is rotated to the open position (retracted position) in FIG. 7A against the spring biasing force to the small aperture position shown in FIG.
[0047]
That is, as shown in FIG. 7B, when the diaphragm blade 634 exists in the opening 631 of the diaphragm unit 630, that is, when the diaphragm blade 634 is in the non-retracted position, the lens control system malfunctions or is in use. When the CCD image sensor 400 is about to be received in the opening 631 of the aperture unit 630 due to mechanical impact of the aperture 630, the engaging rod 629 is moved to the cam portion of the aperture blade 634 before the CCD image sensor 400 contacts the aperture blade 634. Since the aperture blade 634 is moved to the retracted position shown in FIG. 7A in contact with the aperture 634b, there is no possibility that the CCD image sensor 400 abuts on the aperture blade 634, and the reliability of the structural strength is ensured. The retractable length can be shortened.
[0048]
As is clear from the above description, according to the present embodiment, when the retracted as shown in FIG. 3, the aperture unit 630 is held in a state where the CCD image pickup device 400 is received in the opening 631 of the aperture unit 630. It is possible to provide a thin digital camera with excellent portability by reducing the dimensions when retracted compared to the conventional one.
[0049]
Next, a second embodiment of the present invention will be described.
[0050]
FIG. 8 is a perspective view schematically showing the aperture unit when retracted in the present embodiment, and the CCD image pickup device arranged behind the aperture unit and fixed to the base.
[0051]
FIG. 8 shows a diaphragm unit 730 having an appearance similar to that of the diaphragm unit 630 shown in FIG. 6 and an engagement rod 729 (engagement member) erected from the base 401 toward the diaphragm unit 730 side and extending in the optical axis direction. )It is shown. The present embodiment is different from the first embodiment only in the shape of the diaphragm unit and the engagement rod, and therefore a duplicate description is omitted. However, the diaphragm unit 730 is centered on the optical axis S. The opening 731 is opened to a size that can receive the CCD image pickup device 400 when retracted, but the amount of light is adjusted during photographing. Further, the aperture unit 730 includes a notch 732 on the extension line of the engagement rod 729 that allows the engagement rod 729 to enter when retracted. The engagement rod 729 of the present embodiment does not have a tapered portion as provided in the engagement rod 629 of the first embodiment, and the shape thereof is a columnar shape.
[0052]
FIGS. 9A and 9B are schematic views showing an example of the structure of the diaphragm blades provided in the diaphragm unit and the operation thereof.
[0053]
The aperture blade 733 is configured to be rotatable around a shaft 734 between an open position shown in FIG. 9A, that is, a retracted position, and a small aperture position shown in FIG. 9B, that is, a non-retracted position. Has been. Note that a drive source for rotating the diaphragm blade 733 around the shaft 734 is not shown. The aperture blade 733 retracts to the side of the aperture 731 of the aperture unit 730 when opened, and does not interfere with the aperture 731, but has a plate portion 733 a of a size that can shield the aperture 731 when the aperture is small (non-retracted state). Is formed on one side, and a small hole 735 through which light passes is formed in the center of the plate portion 733a. On the opposite side of the diaphragm blade 733 from the plate 733a side with respect to the shaft 734, it does not interfere with the notch 732 of the aperture unit 730 when opened, but the notch 732 is closed when the aperture is small, and the engagement rod 729 A plate portion 733b (regulation member) that regulates the engagement into the notch 732 is provided. Further, a reinforcing plate 736 for increasing the strength of the plate portion 733b is attached to the plate portion 733b. Instead of providing the reinforcing plate 736 separately from the plate portion 733b, the plate portion 733b itself is thickened. It may be formed.
[0054]
By providing the engaging rod 729 and the diaphragm blade 733 having such a configuration, when the lens barrel is retracted, the diaphragm blade 733 is moved to the retracted position and the aperture of the diaphragm unit 730 is opened as shown in FIG. Since the opening 731 and the notch 732 are opened, the rear group lens 112 is allowed to enter the opening 731 and the engaging rod 729 is allowed to enter the notch 732, thereby shortening the collapsed length.
[0055]
As shown in FIG. 9B, when the diaphragm blade 733 is in the non-retracted position, the lens control system or the light quantity control system is not opened to a predetermined opening diameter when retracted due to a malfunction of the lens control system or the light quantity control system or a mechanical impact during use. In this case, prior to the contact between the aperture blade 733 in the non-retracted position and the CCD image sensor 400, the plate portion 733b of the aperture blade 733 comes into contact with the tip of the engagement rod 729, and the CCD image sensor 400 and the aperture unit are contacted. Since the further approach with 730 is blocked | prevented, there is no possibility that the diaphragm blade | wing 733 will be destroyed by contact with a CCD image pick-up element.
[0056]
As is apparent from the above description, according to the second embodiment, when the lens retracted as shown in FIG. 3, the aperture unit 730 is held in a state where the CCD image pickup device 400 is received in the opening 731 of the aperture unit 730. It is possible to provide a thin digital camera with excellent portability by reducing the time dimension as compared with the prior art.
[0057]
As shown in FIG. 9B, when the diaphragm blade 733 is present in the opening 731 of the shutter unit 730, that is, when the diaphragm blade 733 is in the non-retracted state, the light quantity control system malfunctions or the machine in use. Even if the CCD image pickup device 400 is to be received in the opening 731 of the shutter unit 730 due to a mechanical impact or the like, the engagement rod 729 erected on the base 401 is stopped before the CCD image pickup device 400 contacts the stop blade 733. Since the CCD image pickup device 400 and the aperture unit 730 are prevented from coming into contact with the plate portion 733b of the blade 733, there is no possibility that the CCD image pickup device 400 contacts the aperture blade 733, and the structural strength is increased. The retractable length can be shortened while ensuring the reliability.
[0058]
In the embodiment described above, the case where the CCD image pickup device 400 is received in the aperture unit when retracted has been described as an example. However, the present invention is not limited to this, and the photographing lens 200 and the CCD image pickup device 400 are not limited thereto. A shutter unit may be disposed between the shutter unit and the CCD image sensor to be received in the opening of the shutter unit when the lens is retracted. Even if not, the effect of the present invention is not reduced.
[0059]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce the dimension in the optical axis direction when the lens barrel is in the retracted state, and it is possible to provide a camera with excellent portability.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a first embodiment of a camera of the present invention.
FIG. 2 is an external perspective view of the first embodiment of the camera of the present invention.
3 is a cross-sectional view of the lens barrel of the camera shown in FIGS. 1 and 2 along the optical axis in the retracted state. FIG.
4 is a cross-sectional view of the same lens barrel as in FIG. 3 along the optical axis in a maximum extended state.
5 is a block diagram showing a circuit configuration of the camera shown in FIG. 1. FIG.
FIG. 6 is a perspective view schematically showing a diaphragm unit at the time of retracting, and a CCD image pickup device disposed behind the diaphragm unit and fixed to a base.
FIG. 7 is a schematic diagram showing an example of the structure of a diaphragm blade provided in the diaphragm unit and its operation.
FIG. 8 is a perspective view schematically illustrating a diaphragm unit at the time of retracting in the second embodiment and a CCD image pickup device disposed behind the diaphragm unit and fixed to a base.
FIG. 9 is a schematic view showing an example of the structure of a diaphragm blade provided in the diaphragm unit and its operation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Camera 12 Flash light emission window 13 Finder objective window 14 Shutter button 100 Lens barrel 101 Fixed frame 102 Driving cylinder 103 Rotating moving cylinder 105 Straight moving frame 200 Shooting lens 201 First group lens 202 Second group lens 212 Second group lens holding Frame 222 Shutter unit 260 Second group lens unit 400 CCD imaging device 629 Engagement rod 630 Aperture unit 631 Opening 632 Notch 633 Actuator 634 Stopper blade 729 Engagement rod 730 Shutter unit 731 Opening 732 Notch 733 Stopper blade

Claims (1)

In a digital camera that generates an image signal by imaging subject light on a solid-state image sensor,
A lens barrel that can freely change the tube length between a relatively long tube length shooting state and a relatively short tube length storage state,
The lens barrel is
A photographing lens that forms an image of subject light on the solid-state imaging device in the photographing state;
When the imaging lens is disposed between the imaging lens and the solid-state imaging device and is in the imaging state, it is in a usage state for controlling the amount of imaging light passing through the imaging lens, and is shifted from the imaging state to the housed state. And a light quantity control member that moves to a position in which the solid-state imaging device is received in the opening and moves to a non-use state with the opening being opened to a predetermined opening diameter. camera.

Images