JP2000028897A - Digital camera equipped with zoom lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize and thin a lens barrel after taking into consideration of a member peculiar to a digital camera and also to miniaturize a camera main body by this way in a digital camera equipped with a zoom lens barrel. SOLUTION: This digital camera is constituted by arranging a low-pass filter 550 having a smaller diameter than a lens barrel at a position between an imaging device 510 arranged on a photographer side in the camera and a photographing lens group 411 held by a movable body 400 arranged nearest to the imaging device side out of plural moving bodies 300 and 400. Then, a flexible cable 312 electrically connecting an electronic part held on any movable body to the camera main body side passes through the zoom lens barrel and is wired to the camera main body side and a flexible cable housing chamber 600 in which the cable 312 is housed in a curved state when the zoom lens barrel is in the shortest state is secured on the outer peripheral surface side of the low-pass filter 550.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera having a zoom function.

[0002]

2. Description of the Related Art Conventionally, digital cameras having a single focus are mainly used, and few cameras perform zooming. Also, in a digital camera that performs zooming, a zoom lens barrel is configured using a lens shutter camera configuration using a silver halide film, and configured using members unique to the digital camera. There was no. Therefore, the zoom lens barrel becomes large, and as a result, the whole camera also becomes large.

[0003] An object of the present invention is to reduce the size and thickness of a digital camera having a zoom lens barrel in consideration of members unique to the digital camera, thereby enabling the camera body to be reduced in size. It is to be. Furthermore, it gives the digital camera a high degree of design freedom.

[0004]

According to the present invention, a digital camera having the following features is provided.
That is, the zoom lens barrel included in the digital camera of the present invention includes a “fixed barrel that is immovable with respect to the camera body” and a plurality of movable bodies that hold the photographing lens group and move relative to the fixed barrel in the optical axis direction. ". In the camera, “an image sensor (such as a CCD) arranged closer to the photographer than the movable member in the optical axis direction” and “the movable member arranged closest to the image sensor among the plurality of movable members are held. A low-pass filter having a diameter smaller than that of the lens barrel is disposed at a position between the lens group and the imaging lens group. Further, a flexible cable for electrically connecting the electronic component held on any of the movable bodies to the camera body side passes through the inside of the zoom lens barrel and is wired to the camera body side, and the zoom lens barrel is in the shortest state (for example, A flexible cable accommodating chamber for accommodating the flexible cable in a curved state when in the retracted state is secured on the outer peripheral surface side of the low-pass filter.

In the digital camera of the present invention having the above structure, a flexible cable which is folded in the zoom lens barrel when the zoom lens barrel is in the shortest state is provided on the outer peripheral surface side of the low-pass filter. Since the zoom lens barrel is compactly accommodated in the accommodation room, the size of the zoom lens barrel can be reduced. As a result, the entire digital camera can be reduced in size and the degree of freedom in design can be increased.

When the "movable member disposed closest to the image sensor" holds an electronic component, the electronic component accommodating chamber for accommodating the electronic component when the zoom lens barrel is in the shortest state is low-passed. If it is secured on the outer peripheral surface side of the filter, it can greatly contribute to the above demand for compactness.

In the present invention, it is preferable to provide a cable pressing portion projecting in the optical axis direction on the “movable member disposed closest to the image sensor”. When the zoom lens barrel is in the shortest state, the flexible cable in the curved state is pressed by the cable pressing portion, so that the bent state of the flexible cable can be more reliably maintained.

Further, in the present invention, an optical path protection stopper for preventing the above-mentioned curved flexible cable from entering the optical path of the photographing light beam going to the low-pass filter is provided on the holder wall holding the low-pass filter. preferable.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic perspective view showing the entire digital camera 10 according to an embodiment of the present invention in a collapsed state. A protective glass 302 fixed to the front surface of a later-described forward barrel appears on a front exterior material 11 that forms a part of the camera body. That is, in the retracted state, it can be seen that the front exterior material 11 and the front surface of the lens barrel are located in the same plane (see FIG. 2).

In the camera, a CCD 510 generally used as an image pickup device in a digital camera is arranged. In FIG. 1, reference numeral 12 denotes a shutter button for photographing,
Reference numeral 13 denotes a memory card insertion slot, and 14 denotes a card ejection button.

FIGS. 2 to 4 show a retracted state, a telephoto state, and a wide-angle state of the zoom lens barrel, respectively. In the illustrated example, the zoom lens barrel is
`` Cylindrical fixed cylinder 10 immovably fixed in the camera body
“0” and “two movable members that respectively hold the photographing lens group and move relative to the fixed barrel 100 in the optical axis direction, that is, the forward barrel 300 and the diaphragm base plate 400”.
The advance barrel 300 and the throttle base plate 400 will be described later in detail.

A rotary cylinder 200 is rotatably fitted on the outer peripheral surface side of the fixed cylinder 100. At a position near the tip of the inner peripheral surface of the rotating cylinder 200, a projection 210 protruding inward is provided. On the other hand, a circumferential groove 110 formed over the entire peripheral surface of the fixed cylinder 100 is formed near the front end of the outer peripheral surface. When the protrusion 210 of the rotary cylinder 200 is slidably fitted in the circumferential groove 110 in the circumferential direction, the rotary cylinder 200
Is relatively rotated with respect to the fixed barrel 100, and the relative movement in the optical axis direction is prohibited.

(1) Description of the forward and backward movement of the lens barrel When the rotary barrel 200 is rotated, the forward barrel 300 and the diaphragm base plate 400 move back and forth in the optical axis direction in conjunction with this rotation. explain.

On the peripheral wall of the fixed barrel 100, three rectilinear guide slots 101 extending parallel to the photographing optical axis are formed parallel to each other at intervals of 120 degrees (only one appears in the figure). ing). On the other hand, cam slots 201 extending in parallel and spirally with each other are formed on the peripheral wall of the rotary cylinder 200 which is fitted to the fixed cylinder 100 so as to be relatively rotatable. Three cam slots 201 are formed for the forward barrel 300 (201a), and three cam slots 201 are formed for the throttle base plate 400 (201b), that is, a total of six cam slots 201 (one each in the figure). Only one at a time).

The forward barrel (movable body) 300 is provided with three follower pins 301 at intervals of 120 degrees in the circumferential direction (only one is shown in the figure). Each follower pin 301
Is inserted into the straight guide slot 101 of the fixed barrel 100 and the cam slot 201a of the rotating barrel 200, so that when the rotating barrel 200 rotates around the fixed barrel 100, the forward barrel 300 rotates in the direction of the photographing optical axis. Instead, it moves back and forth relative to the fixed barrel 100.

Similarly to the case of the forward barrel 300, the aperture base plate (movable body) 400 is also provided with three follower pins 401 at intervals of 120 degrees in the circumferential direction (one in FIG. 1). Only appears). In other words, when the rotary barrel 200 rotates around the fixed barrel 100, the diaphragm base plate 400 moves back and forth without rotating in the direction of the photographing optical axis on the same principle as that of the forward barrel 300.

A gear portion 211 is formed all around the outer peripheral surface near the rear end portion (photographer side end portion) of the rotary cylinder 200, and driving force from a drive system (not shown) is applied to the gear portion 211. 211
Is transmitted to the rotary cylinder 200 via the When the rotary barrel 200 rotates, the forward barrel 300 and the throttle base plate 400 are accordingly moved.
Move back and forth in the optical axis direction while changing the relative distance from each other. As a result, the zoom lens barrel is selectively controlled to the retracted state in FIG. 2, the telephoto state in FIG. 3, and the wide-angle state in FIG. be able to.

(2) Description of the Forward Tube 300 Next, the configuration of the forward tube 300 will be described. A focus base plate 310 that supports a focus motor 311 is fixed inside the advance barrel 300, and the focus motor 311 is connected to a control mechanism (not shown) on the camera body side by a flexible cable 312. Flexible cable
312 is held and fixed to the inner peripheral surface of the advance barrel 300 with a double-sided tape, a metal fitting, or the like. A ball frame 320 that holds the first lens group 321 is disposed further inside the focus base plate 310. The first lens group 321 is attached to the ball frame 3 by bonding or “caulking”.
Fixed to 20.

The lens frame 320 is urged toward the subject (left side in the figure) by a spring 322, and is driven in the optical axis direction by a helicoid screw 323 engaged with the outer peripheral surface thereof. That is, since the helicoid screw 323 is connected to the focus motor 311 by a gear train (not shown), the focus motor 311 drives the first lens group 321 forward and backward so as to form an image on an imaging surface of a CCD described later. Focusing can be performed.

A transparent protective glass 302 for protecting the first lens group 321 is fixed to the front surface of the forward barrel 300 with an adhesive or a double-sided tape. Further, a ring-shaped optical path regulating plate 325 is provided so as to cover the outer peripheral edge of the front surface of the first lens group 321. The optical path regulating plate 325 reduces flare caused by the light passing through the first lens group 321 being reflected by the inner peripheral surface of the lens frame 320 and the like. Holding plate 326
Is a helicoid screw 3 between itself and the focus base plate 310.
23 with the focus base plate 310
It is screwed to. A rib 327 protruding forward is formed on the front surface of the holding plate 326, and the rib 327 engages with the groove 303 formed on the inner surface side of the advance barrel 300 in a telescopic manner to enhance the light blocking effect. ing.

(3) Description of the Diaphragm Plate 400 Next, the configuration of the diaphragm plate 400 will be described. Aperture base plate 400
Holds a diaphragm mechanism unit composed of a fixed diaphragm 414 and a movable diaphragm 415, and also holds the second lens group 411 in a substantially cylindrical lens holding unit 410.

The fixed diaphragm 414 is a plate member having an opening, and is fixed to the diaphragm base plate 400 with screws. The movable diaphragm 415 is a plate member having a plurality of diaphragm holes, and is rotatably supported by the diaphragm base plate 400. A ring-shaped aperture driving cam 417 is fitted around the cylindrical lens holding portion 410. A cam groove 418 is formed on the front surface of the aperture driving cam 417, and a cam pin 416 fixed to the movable aperture 415 is fitted in the cam groove 418. Therefore, when the driving cam 417 rotates by receiving the driving force from the aperture driving motor 451 fixed to the motor holding base plate 450 described later, a predetermined aperture hole on the movable aperture 415 and the opening of the fixed aperture 414 and Align.

A motor holding base plate 450 holding an aperture driving motor 451 is fixed to a position on the photographer side (right side in the drawing) of the aperture base plate 400 with respect to the lens holding portion 410. Further, two cable pressing ribs 452 protruding in the optical axis direction toward the photographer are formed from the motor holding base plate 450. The operation of these ribs 452 will be described later.

As can be understood from the above description, the motor holding base plate 450 moves forward and backward in the optical axis direction integrally with the stop base plate 400. In other words, the stop base plate 400 and the motor holding base plate 450 integrally constitute one movable body, and in the illustrated embodiment, this is the “movable body disposed closest to the image sensor”. And the cable pressing rib 452 is formed on this movable body.

(4) Description of Image Sensor Peripheral In a digital camera, CC is generally used as an image sensor.
D is used. CCD is a charge coupled device
By electrically processing an image formed on the imaging surface, the image can be displayed on a display means such as an LCD or recorded on a memory card or the like. In the illustrated example, a CCD is attached to the end of the fixed barrel 100 on the photographer side.
The mounting plate 500 is fixed.
0 is fixed (however, the CCD does not necessarily need to be inside the lens barrel). The mounting plate 500 is provided with a CCD positioning rib 501 for determining the height position of the CCD 510, so that the position of the CCD 510 with respect to the mounting plate 500 can be adjusted. Therefore, the positioning of the CCD 510 with respect to the zoom lens barrel can be performed by positioning the mounting plate 500 with respect to the zoom lens barrel as follows. That is, the mounting plate 500 can be positioned in the height direction with respect to the zoom lens barrel by bringing the positioning contact portion 502 into contact with the inner surface of the fixed barrel 100. Positioning in the optical axis direction can be performed by inserting an adjustment washer between the fixed cylinder 100 and the mounting plate 500, or the like.

Each terminal 511 from the CCD 510 is connected to a mounting plate 500.
Are connected to a control system (not shown) provided outside the lens barrel through the two openings 503 provided in the lens barrel. Each of these openings 503 is
After the positioning of the CCD 510 with respect to the zoom lens barrel as described above, the CCD 510 is closed by an adhesive or the like, thereby preventing light from entering. Further, by fixing with the adhesive in this manner, the CCD 510 is immovable with respect to the mounting plate 500.

An opening 504 is provided on the mounting plate 500 at a position corresponding to the back side of the fixed CCD 510, and is used as follows. That is,
After fixing the CCD 510 to the mounting plate 500,
If 510 is determined to be defective, the CCD 510 is removed from the mounting plate 500 by pushing a bar or the like through the opening 504. That is, although the CCD 510 itself is defective, the mounting plate 500 can be reused. Alternatively, the CCD 510 is attached to the mounting plate 50.
Even if it becomes necessary to change the fixing position after fixing to 0, the CCD 510 can be similarly removed using this opening 504.

At a position on the front side of the CCD 510, a low-pass filter 550 is arranged. The low-pass filter is
Considering the optical characteristics of CCD, taking lens group and CCD
Are arranged between them. Low-pass filter 550
Are held by a holder member 560 formed by combining a plurality of cylinders having different diameters. More specifically, holder member 5
It is fixed using an adhesive or the like in a state of being fitted inside the holder peripheral wall 561 having the smallest diameter located at the forefront of the holder 60. The periphery of the opening provided on the front surface of the holder member 560 for guiding the light beam that has passed through each photographing lens to the low-pass filter 550 is an inclined surface 563, and the diameter thereof is
It is slightly smaller than the outside diameter of 50. This is to reduce flare caused by light reflected on the inner surface of the holder peripheral wall 561.

An optical path protection stopper 562 extending obliquely from the tip of the holder peripheral wall 561 toward the subject and toward the radial outside of the zoom lens barrel is provided. The function of the optical path protection stopper 562 will be described later.

A substantially cylindrical elastic member 520 is compressed and held between the holder member 560 and the CCD 510. The elastic member 520 surrounds the optical path from the low-pass filter 550 to the CCD 510, and prevents foreign matter such as dust from entering the area. The CCD 510 is attached to the mounting plate 500.
To prevent displacement of the position of the CCD 510.

At a position near the photographer's end on the inner peripheral surface of the fixed barrel 100, a positioning rib 103 projecting inward is formed. On the other hand, the holder member 560 is
Although biased toward the subject side (left side in the figure) by 20, the substrate 565 of the holder member 560 comes into contact with the positioning rib 103, whereby the positioning of the holder member 560 in the photographing optical axis direction is performed. . The vertical and horizontal alignment of the holder member 560 is achieved by the holder member 560 being inscribed in the fixed cylinder 100.
The reason why the position of the holder member 560 is accurately positioned in this way is to accurately position the low-pass filter 550 held by the holder member 560.

The description of the overall configuration of the zoom lens barrel is now completed, and the characteristic operation of the present invention will be described below.

In the wide-angle state shown in FIG. 4, the flexible cable 312 extends from the right end in the drawing of the inner peripheral surface of the advance barrel 300 in the drawing.
The light passes through the side of 400, passes through a gap between the fixed barrel 100 and the holder member 560, passes through a slit-shaped opening 505 formed in the CCD mounting plate 500, and reaches the outside of the lens barrel. The flexible cable 312 is in the most extended state in the wide angle state in FIG.

The flexible cable 312 is slightly loosened in the telephoto state shown in FIG. 3 in which the forward barrel 300 is slightly retracted from the state shown in FIG. 4, and further largely loosened in the collapsed state shown in FIG. In the zoom lens barrel of the digital camera according to the present invention, the diameter of the low-pass filter 550 is made smaller than the diameter of the lens barrel, thereby securing a predetermined space on the outer peripheral surface side of the low-pass filter 550. In particular, the second lens group 411
The outer peripheral surface of the low-pass filter 550 in the retracted state in FIG. 2 and the wide-angle state in FIG. 4 in which an integral movable body composed of the diaphragm base plate 400 and the motor holding base plate 450 that move forward and backward approaches the holder member 560. The predetermined space secured on the side has a state like an annular room.

In the present invention, this annular room is used as the flexible cable accommodation room 600. Two cable pressing ribs 452 are provided from the motor holding base plate 450 toward the photographer. These ribs452
In the collapsed state (FIG. 2), the flexible cable 312 which is folded in the flexible cable storage chamber 600 and accommodated in a curved state is pressed to maintain the curved state. Thereby, the flexible cable 312 is held in a more stable state in the lens barrel.

As can be seen from FIG. 2, an optical path protection stopper 562 protruding from the end of the holder peripheral wall 561 of the holder member 560 holding the low-pass filter 550 protects the optical path from the curved flexible cable 312. That is, the stopper 562 effectively prevents a part of the curved flexible cable 312 from entering the optical path from the second lens group 411 to the low-pass filter 550.

In the illustrated embodiment, there are only the first and second photographing lens groups provided in the zoom lens barrel. However, a zoom lens barrel having three or more photographing lens groups may also be used. The invention is equally applicable. Then, when the movable body holding the photographing lens group arranged on the side closest to the imaging device (CCD) arranged on the photographer side in the camera holds some electronic components
(In the illustrated example, the aperture driving motor 451 held on the motor holding base plate 450 that moves forward and backward together with the second lens group 411)
In the above, the annular room as the electronic component accommodation room 700,
Further effective use becomes possible.

As can be seen from FIG. 2, the cable pressing rib 452 is eliminated, and the aperture driving motor 451 is positioned at that position.
Is arranged, the motor 451 can replace the cable pressing rib 452. In this case, some other camera element can be arranged in the electronic component housing room 700, which is further advantageous in terms of miniaturization and thinning of the camera.

In the embodiment described above, the retractable type in which the entire zoom lens barrel is accommodated in the camera body when the zoom lens barrel is in the shortest state in which it is most contracted has been described. The present invention can be applied not only to such a retractable type zoom lens barrel, but also to a digital camera having a zoom lens barrel in which a part of the zoom lens barrel projects outside the camera in the shortest state.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a digital camera according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a zoom lens barrel employed in the digital camera of FIG. 1 in a collapsed state.

3 is a sectional view showing the zoom lens barrel in FIG. 2 in a telephoto state.

FIG. 4 is a sectional view showing the zoom lens barrel in FIG. 2 in a wide-angle state.

[Explanation of symbols]

 10 Digital camera 11 Front exterior material 12 Shutter button 13 Memory card insertion slot 14 Card removal button 100 Fixed cylinder 101 Straight guide slot 103 Positioning rib 110 Circular groove 200 Rotating cylinder 201a, 201b Cam slot 210 Projection 211 Gear part 300 Forward cylinder 301 Follower pin 302 Protective glass 303 Groove 310 Focus base plate 311 Focus motor 312 Flexible cable 320 Ball frame 321 First lens group 322 Spring 323 Helicoid screw 325 Optical path regulating plate 326 Press plate 327 Rib 400 Aperture base plate 401 Follower pin 410 Lens holding part 411 2 lens group 414 Fixed aperture 415 Movable aperture 416 Cam pin 417 Aperture drive cam 418 Cam groove 450 Motor holding base plate 451 Aperture drive motor 452 Cable pressing rib 500 CCD mounting plate 501 CCD positioning rib 502 Positioning contact section 503, 504, 505 Opening 510 CCD 511 Terminal 520 Elastic member 550 Low-pass filter 560 Holder member 561 Holder peripheral wall 562 Optical path protection stopper 563 Inclined surface 565 Board 600 Flexible cable storage room 700 Electronic component storage room

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H044 EC01 EC07 2H100 AA01 BB05 BB06 BB11 CC07 2H101 DD21 DD66 5C022 AA11 AB12 AB23 AB44 AB66 AC34 AC42 AC54 AC55 AC74 AC75 CA02

Claims (4)

[Claims] 1. A camera, comprising: a zoom lens barrel including a fixed barrel that is immovable with respect to a camera body, and a plurality of movable bodies that hold a photographing lens group and relatively move in the optical axis direction with respect to the fixed barrel. Within, the position between the imaging element arranged closer to the photographer than the movable body in the optical axis direction and the imaging lens group held by the movable body arranged closest to the imaging element side of the plurality of movable bodies A digital camera having a low-pass filter smaller in diameter than the lens barrel, wherein a flexible cable for electrically connecting an electronic component held on any movable body to the camera body side passes through the inside of the zoom lens barrel. The flexible cable housing chamber that houses the flexible cable in a curved state when the zoom lens barrel is in the shortest state is connected to the camera body side by A digital camera that is secured on the side. 2. When the zoom lens barrel is in the shortest state, an electronic component accommodation chamber for accommodating electronic components held by the movable body disposed closest to the image sensor is secured on the outer peripheral surface side of the low-pass filter. 3. The method according to claim 1, wherein
Digital camera as described. 3. A cable pressing portion protruding in an optical axis direction is provided on the movable body disposed closest to the image pickup element, wherein the cable pressing portion is provided when the zoom lens barrel is in the shortest state. 2. The flexible cable in a bent state is pressed to maintain the bent state.
Or the digital camera according to 2. 4. An optical path protection stopper for preventing the flexible cable in a curved state from entering the optical path of a photographing light beam going to a low-pass filter is provided on a holder wall holding the low-pass filter. The digital camera according to claim 1, 2 or 3.