JPH0548476U - Imaging device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an image pickup device in which the conversion lens can be quickly inserted and removed, and can be driven with high accuracy during focusing, and the load can be reduced and the size and weight can be reduced. [Structure] In this apparatus, a lens frame 2 holding a taking lens 3 is fixed, and an image pickup device holder 6 is relatively moved by rotation of a screw shaft 4 to perform focusing.
Further, in order to insert / remove the conversion lens 12 into / out of the photographing optical path, the lens holding frame 11 is moved to a predetermined position by the drive lever 17 operated in accordance with the movement of the image pickup device holder 6. And the screw shaft 4
The moving pitch of the screw part is small in the focusing area and large in the conversion lens driving area.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus having an image pickup optical system having a conversion lens built therein.

[0002]

[Prior Art]

 In an image pickup device using an image pickup device, such as a video camera or a still video camera, which has a built-in conversion lens, it is necessary to insert or retract the conversion lens into or out of the optical path. is there. As the insertion / retraction mechanism, the conventional one uses the screw shaft 34 and the cam plate 37 having screw parts of equal pitch as shown in the perspective view of the image pickup mechanism of FIG. It was inserted or retracted in or out of the optical path. The mechanism will be described in more detail. The screw shaft 34, to which a gear 36 is fixed, is rotatably supported on the main plate 31 in a state parallel to the optical axis, and the guide shaft 35 is fixed to the opposite side thereof. Has been done. Then, a lens frame unit 32 including a photographing lens 33, a diaphragm mechanism, a drive mechanism (not shown) for AF (autofocus), and a rear conversion lens 39 held by a conversion lens frame 38 is built in. The screw shaft 34 and the guide shaft 35 are movably supported in the optical axis direction via a nut portion 32a and a notch 32b, respectively. The movement in the optical axis direction is performed by rotating the screw shaft 34 via a gear 36. The conversion lens frame 38 is supported by the lens frame unit 32 via a pin 40, and is driven by the cam plate 37 as the lens frame unit 32 moves in the optical axis direction, and is rotated around the pin 40. To do. By the rotation, the rear conversion lens 39 can be inserted into or retracted from the optical path of the taking lens 33. Although not shown in FIG. 6, the image pickup device is fixed to the main body or the base plate 31 behind the lens frame unit.

FIG. 7A and FIG. 8A are plan views of the image pickup mechanism. FIG. 7A shows the lens frame unit 32 retracted and the rear conversion lens 39 passes through the optical path. 8A shows a state in which the lens frame unit 32 is moved forward and the rear conversion lens 39 is inserted into the optical path. 7B and FIG. 8B are a sectional view taken along the line AA of FIG. 7A and a sectional view taken along the line BB of FIG. 8A, respectively. As shown in FIGS. 7 and 8, since the conversion lens frame 38 supported by the lens frame unit 32 is biased by the spring 41, the tip end 38a of the conversion lens frame 38 is cam surfaces 37a, 37b, 37c of the cam plate 37. Will come into contact with and slide. Then, by rotating the screw shaft 34, the unit 32 moves forward and backward, and the forward and backward movement causes the conversion lens frame 38 to move to the position where the rear conversion lens 39 is inserted in the optical path or the retracted position based on the cam shape. Is rotated to. When the front end of the conversion lens frame 38 is on the cam surface 37b, the rear conversion lens 39 is inserted in the optical path and the image can be picked up, and the lens movement for focusing and exposure are performed. When it is on the cam surface 37c, the rear conversion lens 39 is in a standard image-capable state retracted from the optical path, and the lens movement and exposure for focusing in the standard state are performed. In these states, since the cam surfaces 37b and 37c are provided in parallel with the optical axis, the conversion lens frame 38 is held at a predetermined position without rotating.

In the above conventional example, the photographing lens is moved in the optical axis direction during focusing, but focusing driving is performed by moving the image pickup element in the optical axis direction instead of the photographing lens side. As an apparatus, an automatic focus adjusting apparatus disclosed in Japanese Patent Laid-Open No. 63-21617 has been proposed. This device relates to an AF device of a type in which an image sensor is moved by an actuator built in the main body. In this apparatus, a belt wound around a pulley on the output shaft of a drive motor is connected to an image sensor support member, and the motor is rotationally driven to move the image sensor in the optical axis direction. By applying this drive system to the conversion lens insertion / removal interlocking mechanism, the image sensor is moved in the optical axis direction to insert / remove the conversion lens, and AF drive is also performed by moving the image sensor in the same way. It is also possible to do so.

[0005]

[Problems to be solved by the device]

 However, in the conventional image pickup mechanism having a conversion lens insertion / retraction mechanism shown in FIG. 6, when the driving load is taken into consideration, the lens barrel unit 32 includes the image pickup lens 33, the diaphragm mechanism, and the AF drive as described above. The mechanism and the conversion lens frame 38 are built-in, and moving it requires a considerable load. Therefore, as the photographic lens 33, the rear conversion lens 39, and the like, it is unavoidable to use the lightest possible one. Further, in the focusing state, the front end portion 38a of the conversion lens frame 38 is in contact with the cam surfaces 37b and 37c of the cam 37. Therefore, the sliding resistance at that time also becomes a large value, and from this point also, it is inevitable to increase the size of the drive system, and it is difficult to increase the speed.

On the other hand, the automatic focus adjusting device disclosed in the above-mentioned Japanese Patent Laid-Open No. 63-21617 has a focusing mechanism of a type that moves the image pickup element, and can be lightweight in terms of load. .. When this image sensor drive mechanism is applied to the interlocking mechanism for inserting / removing the conversion lens and focusing drive, this device directly drives the image sensor by the belt wound around the pulley of the motor output shaft. Therefore, the driving speed must be constant speed driving. Therefore, the conversion lens switching speed becomes the same as the AF processing speed, and the switching operation cannot be performed swiftly.

The present invention has been made to solve the above-described problems, and the focusing lens and the insertion / removal drive of the conversion lens are performed in association with the driving of the image pickup element. It is an object of the present invention to provide an imaging device that can be quickly inserted / removed and driven with high precision for focusing, reduce the motor load, and can be reduced in size and weight.

[0008]

[Means for Solving the Problems]

 In the image pickup apparatus of the present invention, a conversion lens for changing the focal length is inserted between the image pickup lens and the image pickup element in order to move the image pickup element relative to the image pickup lens for focusing. A conversion lens moving means for detachably moving and a mechanical control means for changing the moving pitch of the image pickup element with respect to the photographing lens when inserting and removing the conversion lens and when focusing are provided.

[0009]

[Action]

 The image pickup device is relatively moved using a predetermined range of the mechanical control means to perform focusing. Then, when the conversion lens is inserted / removed, that is, inserted into or retracted from the photographing optical path, the conversion lens is driven using an area outside the range in which the mechanical control means performs the focusing. Then, the moving speed of the image pickup device is made different when the conversion lens is moved and when the focus is adjusted.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a drive mechanism portion of an image pickup apparatus showing an embodiment of the present invention. As shown in the figure, the present apparatus is an image pickup apparatus such as a video camera using an image pickup element, in which a lens frame 2 holding a taking lens 3 is fixed to a main plate 1, and an image pickup element holder 6 is mechanically controlled. It is assumed that the screw shaft 4 as a means is rotated to relatively move the lens for focusing. Further, in order to insert / remove the conversion lens 12 in / out of the photographing optical path on the optical axis O, the conversion lens 12 is held by the driving lever 17 of the moving means operated in accordance with the movement of the image pickup device holder 6. The conversion lens holding frame 11 is rotated and moved to a predetermined insertion / removal position. The lead of the screw portion of the screw shaft 4, that is, the moving pitch, is formed differently in the focusing region and the conversion lens driving region, and the lead angle is set larger in the conversion lens driving region. ..

To explain the above mechanism in more detail, a U-shaped base plate 1 is fixed to the rear of the lens frame 2 to a camera body (not shown). The screw shaft 4 having a drive gear 9 fixed thereto is rotatably supported on the main plate 1 in a state parallel to the optical axis O, and a guide shaft 5 is fixed to the opposite side thereof. Further, the conversion lens frame 11 is rotatably supported by a pin 1a fixed to the base plate 1, and can be inserted into and retracted from the optical path of the taking lens 3. The image pickup device holder 6 is supported by the screw shaft 4 and the guide shaft 5 by a guide portion 6a and a notch 6b (see FIG. 4) of the holder 6, respectively, and is supported so as to be movable in the optical axis O 2 direction. .. Then, as shown in the cross-sectional view of the screw shaft portion in FIG. 2, in the guide portion 6a of the image sensor holder 6, the drive pin 8 is fixed to the tip of the leaf spring 7 that is screwed and fixed. The tip portion of 8 is inserted into the guide portion 6a. Then, it is slidably fitted in a lead groove provided in the screw shaft 4. Therefore, when the screw shaft 4 rotates, the image pickup device holder 6 is moved in the optical axis direction via the drive pin 8. Further, in order to remove the back and forth movement of the driving position of the image pickup device holder 6, a pressing spring 10 is brought into contact with the back surface of the gear 9 to press the screw shaft 4 toward the taking lens 3 side.

The lead formed on the screw shaft 4 does not have a constant lead angle, as shown in FIG. That is, the entire movement range is divided into three areas, that is, the lead areas Ra, Rb, and Rc. The lead areas Ra and Rc have small lead angles, and the lead area Rc has a large lead angle. The lead regions Ra and Rc among these three regions are regions in which the screw shaft 4 is rotated to move the image sensor holder 6 to perform the focusing operation. The region Rb is a region where the screw shaft 4 is rotated to move the image pickup element holder 6 and the movement causes the conversion lens 12 to be inserted into and removed from the photographing optical path. Further, the boundary portions B1 and B2 of these areas are areas where the above two operations are switched, and areas where neither focusing operation nor insertion / removal operation is performed.

FIG. 3 is a cross-sectional view of the image pickup mechanism, particularly the image pickup element holder 6. This figure shows a state in which the imaging element holder 6 is moved forward and the conversion lens 12 is retracted from the optical path. An image pickup device 14 fixed to the holding plate 13 by adhesion or the like is built in the inside of the image pickup device holder 6, and the holding plate 13 is screwed to the image pickup device holder 6. A crystal low-pass filter 16 is inserted in front of the image pickup device holder 6 and is pressed and fixed by the image pickup device 14 via an elastic member 15. Further, the position of the image pickup holder 6 in which the image pickup device 14 is built in must always be detected by the control unit (not shown) of the camera during focusing processing and lens switching processing. Therefore, a position sensor 19 such as a slide type variable resistor is fixed to the base plate 1, and the image pickup device holder 6 operates the operating portion 19a to detect the position of the image pickup device holder 6.

FIG. 4 is a cross-sectional view taken along the line CC of FIG. 3. FIG. 4A shows a state in which the conversion lens 12 is retracted from the optical path, and FIG. 4B shows a conversion lens. 12 shows a state in which 12 is inserted in the optical path. Further, FIGS. 5A and 5B are DD sectional views of FIG. 4A and EE sectional view of FIG. 4B, respectively. As shown in FIGS. 4 and 5, a drive lever 17 is rotatably attached to the pin 1b fixed to the bottom surface of the main plate 1. A toggle spring 18 whose other end is engaged with a pin 17d of a drive lever 17 is rotatably attached to the pin 1c which is also fixed to the bottom surface of the main plate 1. Further, stopper pins 1d and 1e with which the drive lever 17 abuts are provided at a predetermined interval on the bottom surface of the main plate 1. The drive lever 17 has a substantially L-shape, and one end of the drive lever 17 is provided with a long groove 17c into which the front end 11a of the conversion lens frame 11 is fitted. Further, at the other end, pin contact surfaces 17a and 17b, with which the operation pin 6c provided on the lower surface of the image pickup device holder 6 can contact, are provided at positions substantially opposite to each other.

Then, the image pickup element holder 6 moves forward to the photographing lens 3 side (extending direction), the operation pin 6c of the image pickup element holder 6 abuts on the pin abutting surface 17a of the drive lever 17, and further forward. Then, when the drive lever 17 exceeds the predetermined neutral position of the toggle spring 18, the drive lever 17 rotates clockwise by its urging force and is held in a state of contacting the stopper 1d side of the main plate 1 ((A in FIG. 5). ) State). In this state, the front end portion 11a of the conversion lens frame 11 is pressed by the long groove 17c, and the conversion lens 12 is rotated clockwise as shown in FIG. Become. On the contrary, the image sensor holder 6 retracts in the direction opposite to the taking lens 3 (retracting direction), the operation pin 6c of the image sensor holder 6 contacts the pin contact surface 17b of the drive lever 17, and further retracts. The drive lever 17 is also held in a state of abutting against the stopper 1e side of the main plate 1 by rotating the drive lever 17 counterclockwise by the urging force of the toggle spring 18 when the predetermined neutral position of the toggle spring 18 is exceeded. (The state of FIG. 5B). In this state, the tip end 11a of the conversion lens frame 11 is pressed by the long groove 17c, and is rotated counterclockwise as shown in FIG. The conversion lens 12 is inserted in the inner space. When the operation pin 6c of the image pickup device holder 6 is moved forward and backward and after contacting the pin contact surfaces 17a and 17b of the drive lever 17, as shown in FIGS. Since the drive lever 17b is rotated in the respective directions by the urging force of the toggle spring 18, the operation pin 6c passes the tip end of the corresponding contact surface 17a, 17b and advances to the focusing operation position. Or retreat. Therefore, during the focusing operation, the drive lever 17 maintains the stationary state.

The operation of the drive mechanism section of the image pickup apparatus of the present embodiment configured as described above will be described. First, in order to take a picture with the conversion lens 12 retracted from the optical path, the gear mechanism 9 is driven by a drive mechanism (not shown), and the screw shaft 4 is rotated counterclockwise as viewed from the shooting lens side to take an image. The element holder 6 is moved forward. The drive pin 8 is located in the lead region Ra of the screw shaft 4. The initial position at this time is set to a position that is convenient for the imaging device, either infinity, the close-up position, or the neutral position in-focus position. Further, in this state, the conversion lens 12 is moved to a position outside the photographing optical path by the action of the drive lever 17 described above ((A) in FIG. 4). Then, in accordance with an instruction from the control unit of the camera, the screw shaft 4 is appropriately rotated to perform focusing. In this case, since the drive pin 8 is located in the lead region Ra as described above, the amount of movement of the image sensor holder 6 with respect to the rotation angle of the screw shaft 4 is small, and accurate focusing is performed. Also, the drive load resistance is small.

Next, in order to switch the focal length and perform shooting, the gear 9 is driven by a drive mechanism (not shown), and the screw shaft 4 is rotated clockwise as viewed from the shooting lens side. The drive pin 8 that drives the image sensor holder 6 moves from the lead region Ra of the screw shaft 4 to the region Rb, and moves forward at the lead angle of the region Rb. Since this lead angle is large as described above, the image sensor holder 6 moves at high speed even when the rotation speed of the screw shaft 4 is constant. In this region, the conversion lens 12 described above is driven so as to be positioned in the photographing optical path, but the operations thereof are processed at high speed. As for the operation at that time, as described above, the drive lever 17 is rotated by the operation pin 6c so as to abut against the stopper 1e side of the main plate 1 (the state of FIG. 5B), and the conversion lens frame 11 is moved. As shown in FIG. 4B, the conversion lens 12 is rotated counterclockwise to insert the conversion lens 12 into the space in the photographing optical path, and the focal length of the photographing optical system is set to be long. After the conversion lens 12 is inserted into the optical path, the image pickup device holder 6 is further retracted, the drive pin 8 is located on the lead region Rc of the screw shaft 4, and based on the small feed angle feed in that region, Shooting processing such as focusing is performed. At this time, the initial position is set to any of infinity, close-up, and neutral position in-focus position, or a position convenient for the image pickup apparatus. When the conversion lens 12 is to be retracted out of the optical path again, the reverse operation of the above operation is performed to rotate the conversion lens frame 11 in the clockwise direction to move the conversion lens 12 out of the optical path. To the state shown in FIG. 4 (A). The subsequent operation is as described above.

As described above, the image pickup apparatus of this embodiment moves the image pickup element holder 6 holding the image pickup element 14 in the optical axis direction in order to insert and remove the conversion lens 12 and focus. In addition, unlike the conventional example, since the photographing lens barrel which is a heavy load is not driven, the driving means can be made compact and compact. Furthermore, the moving pitch (lead angle) is changed when the conversion lens 12 is inserted / removed and during focusing, and the movement pitch is increased when the conversion lens 12 is inserted / removed so that the insertion / removal operation is completed as quickly as possible. In addition, the moving pitch is reduced during focusing to enable accurate positioning of the image sensor holder 6. Further, since the drive system of the screw shaft 4 at the time of focusing operation is separated from the drive lever 17 of the insertion / removal mechanism of the conversion lens 12, the load at focusing is reduced.

[0019]

[Effect of the device]

 As described above, in the image pickup apparatus of the present invention, in which the image pickup element is moved to perform focusing, the movement pitch of the mechanical control means is changed when the conversion lens is inserted / removed and when the focus is adjusted. Therefore, the present invention enables the conversion lens to be quickly inserted and removed, and at the same time enables accurate positioning of the image sensor when focusing, and further reduces the drive load and drive. It has many remarkable effects such as downsizing and downsizing of the system.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a mechanism portion of an image pickup apparatus showing an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a screw shaft portion of a mechanical portion of the image pickup apparatus shown in FIG.

FIG. 3 is a cross-sectional view of a mechanical portion of the image pickup apparatus shown in FIG.

4A and 4B are sectional views taken along the line CC of FIG. 3, in which FIG. 4A shows a state in which the conversion lens is retracted from the optical path, and FIG. 4B shows a state in which the conversion lens is inserted in the optical path.

5 is a sectional view of FIG. 4 described above, in which (A) is a sectional view taken along the line DD of FIG. 4A, and (B) is taken along the line EE of FIG. 4B.
A sectional view is shown.

FIG. 6 is a perspective view of a mechanical portion of an image pickup apparatus showing a conventional example.

7 is a plan view showing a state where the conversion lens of the mechanism section of the image pickup apparatus of FIG. 6 is retracted from the optical path, FIG.
(B) is AA sectional drawing of (A) of the said top view.

8 is a plan view showing a state where the conversion lens of the mechanism section of the image pickup apparatus of FIG. 6 is inserted into the optical path, FIG.
(B) is a BB sectional view of (A) of the above plan view.

[Explanation of symbols]

3 …………………… Shooting lens 4 …………………… Screw shaft (mechanical control means) 6c …………………… Operation pin (conversion lens moving means) 8 …………………… Drive pin (mechanical control means) 14 …………………… Image sensor 12 …………………… Conversion lens 17 …………………… Drive lever (conversion lens moving means) 18 ……………… ...... Toggle spring (conversion lens moving means)

Claims (1)

[Scope of utility model registration request] 1. In an image pickup apparatus for focusing by moving an image pickup element relative to a photographing lens, a conversion lens for changing a focal length is detachably moved between the photographing lens and the image pickup element. An image pickup apparatus comprising: a conversion lens moving means for controlling the movement of the image pickup element with respect to the photographing lens; .