JPH08223464A - Camera and its focus adjustment method - Google Patents

Abstract

PURPOSE: To obtain a camera whose focus is adjusted without moving an image pickup lens. CONSTITUTION: The camera is provided with an image pickup lens 3 receiving an image of an object, an image pickup element 6 receiving optical information from the image pickup lens 3 and converting it into an electric signal, and an image pickup element moving means 7 moving the image pickup element 6 in parallel with an optical axis L of the image pickup lens 3. The image pickup element moving means 7 is made up of a shaft 9 reciprocated in parallel with the optical axis L by the turning of a turning ring 8 and a support member 10 fitted to one end of the shaft 9 and supporting the image pickup element 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique effectively applied to focus adjustment of a camera.

[0002]

2. Description of the Related Art For example, a CCD (Charge
In a camera using a Coupled Device, etc., the photographing lens is moved parallel to the optical axis to adjust the focus.

In order to move the taking lens, it is necessary to screw a special trapezoidal screw called a helicoid to the body side and rotate the helicoid to which the taking lens is attached.

[0004]

However, according to the above-mentioned technique, the moving mechanism of the photographing lens becomes large and complicated, so that the cost is inevitably increased.

A motor is used to move the photographing lens electrically, but the motor used here is required to be small in size and high in torque due to the limitation of the installation space, which also increases the cost. .

Further, according to the above-mentioned moving mechanism, the photographing lens moves while being rotated by the helicoid,
In many cases, it is difficult to make the portions of the shooting lens equidistant from the optical axis have the same curvature. In such a case, rotation causes deterioration of image forming performance, image distortion, or reduction of the lens effective diameter. The decrease in light quantity becomes a problem.

Therefore, an object of the present invention is to provide a technique capable of adjusting the focus without moving the taking lens.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0009]

The typical ones of the inventions disclosed in the present application will be outlined below.

That is, the camera according to the present invention includes a photographing lens for taking in an image of a subject, an image pickup element for receiving optical information from the photographing lens and converting the optical information into an electric signal, and the image pickup element for the optical axis of the photographing lens. And an image pickup device moving means for moving the image pickup device in parallel.

The image pickup device moving means can be composed of a shaft which is reciprocated in parallel with the optical axis by the rotation of the rotation drive section, and a support member which is attached to one end of the shaft and supports the image pickup device. . A rotary ring screwed to the shaft and manually rotated can be used as the rotary drive unit, or a motor for rotating a screw shaft screwed to the shaft can be used. Further, a charge coupled device can be used as the image pickup device.

Further, by providing a casing fixing member inside the body and attaching the taking lens to the lens casing, the lens casing can be fixed to the casing fixing member so that the lens casing does not protrude from the body.

In the focus adjusting method of the camera according to the present invention, the taking lens is fixed, and the image pickup device for receiving optical information from the taking lens is moved in parallel with the optical axis of the taking lens to perform the focusing. is there.

[0014]

According to the above means, the focus can be adjusted without moving the taking lens by moving the image pickup device in parallel with the optical axis of the taking lens.

This eliminates the need for a helicoid or the like, so that the lens effective diameter can be increased correspondingly, and the imaging performance of the photographing lens can be improved, the image distortion, and the peripheral light amount can be improved.

Further, even when the image pickup element is electrically moved by the motor, the motor can be installed in the body. Therefore, the motor is not a small-sized and high-torque expensive motor, but a larger and cheaper motor. Can be used.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. In all the drawings for explaining the embodiments, the same members are designated by the same reference numerals, and the repeated description thereof will be omitted.

(Embodiment 1) FIG. 1 is a sectional view schematically showing a camera according to an embodiment of the present invention.

As shown in the figure, in the camera of this embodiment,
A lens casing 2 is provided so as to project from the body 1, and a photographing lens 3 that captures an image of a subject is attached to the inside of the lens casing 2. The lens casing 2 is screwed to the body 1, for example. Therefore, in the camera of this embodiment, the taking lens 3
No moving mechanism is provided for moving the lens in parallel with the optical axis L. It should be noted that various types of such lens casings 2 are prepared, and different photographing lenses 3 are fixed to the respective lens casings 2, whereby the photographing lenses 3 can be easily replaced.

Element casing 5 installed in the body 1
An image sensor 6 that receives optical information of the taking lens 3 and converts the optical information into an electric signal is provided therein. The image sensor 6 installed on the optical path of the taking lens 3 is, for example, C
The interface charge under the metal electrode, which is composed of a CD and is provided on the silicon substrate, is moved by the optical information from the photographing lens 3 to generate an electric signal. It should be noted that the image pickup device 6 does not necessarily have to be formed of such a CCD, and may be, for example, a BBD (Bucket Brigade Device).
ce), MOS (Metal Oxide Semiconductor), CID (C
harge Injection Device) can be used.

The image pickup device 6 is moved by the image pickup device moving means 7 in parallel with the optical axis L of the taking lens 3. That is, the image pickup device moving means 7 is attached to one end of the shaft 9 and a shaft 9 having a thread groove formed on the outer periphery of the rotary ring (rotational drive portion) 8 and a thread groove threadably coupled to the thread groove. And a support member 10 for supporting the image pickup device 6. The rotational force of the rotary ring 8 is converted into thrust by the screw coupling action of the two, and the shaft 9 becomes parallel to the optical axis L, in other words, the image pickup device 6 mounted on the mounting substrate 11 becomes parallel to the optical axis L. It is designed to reciprocate.

The rotating ring 8 is rotatably engaged with the body 1 by an engaging groove 8a formed in an annular shape on the outer periphery of the rotating ring 8, and is manually rotated by grasping a portion of the body 1 protruding to the outside. It is like this. The shaft 9
Is connected to the support member 10 in the element casing 5 by penetrating a shaft hole 5a formed in the element casing 5.

In the camera of this embodiment, the rotary ring 8 is manually rotated to adjust the focus.

In other words, the shaft 9 is reciprocally moved in the axial direction by the rotation of the rotary ring 8, whereby the image pickup device 6 is moved in parallel with the optical axis L. Then, due to such movement of the image pickup device 6, the image pickup device 6 and the photographing lens 3 are moved toward and away from each other, and the relative distance is changed. Therefore, by adjusting the rotating ring 8 and moving the image pickup device 6 to the focal position, the camera is focused.

As described above, by moving the image pickup device 6 in parallel with the optical axis L of the taking lens 3 by the image pickup device moving means 7, it becomes possible to adjust the focus even when the taking lens 3 is fixed. Therefore, although the image pickup device moving means 7 is required, it is simpler than the large and complicated moving mechanism of the taking lens 3, so that the cost can be reduced as a whole.

Further, since the taking lens 3 is fixed and the lens effective diameter becomes large, it is possible to improve the image forming performance of the taking lens 3, the distortion of the image, the amount of peripheral light and the like.

(Embodiment 2) FIG. 2 is a sectional view showing a camera according to another embodiment of the present invention.

The camera of this embodiment is different from the camera of the first embodiment in that the image pickup device 6 is electrically moved.

That is, in this embodiment, the motor 18 is used as the rotation driving unit, and the rotation of the motor 18 causes the shaft 9 to reciprocate in the axial direction so that the image pickup device 6 is moved in parallel with the optical axis L. It has become.

The shaft 9 having a thread groove on the outer periphery is
A screw groove that is screwed to the shaft 9 is screwed to a screw shaft 12 formed on the inner circumference. The screw shaft 12 is rotatably attached to a slip coupling 13 provided on the body 1, and has a first spur gear 14 on its outer periphery.
Has been fixed. Then, the second spur gear 15 that meshes with the first spur gear 14 and rotates the same is attached to the shaft 16 of the motor 18. The gear ratio between the first spur gear 14 and the second spur gear 15 is, for example, 6:
It is set to 1 to enable fine adjustment of the position of the image sensor 6 for convenience of focus adjustment. If the rotary ring 8 (FIG. 1) shown in the first embodiment is used in place of the motor 18, it is possible to finely adjust the position of the image pickup device 6 manually. Alternatively, the motor 18 may be operated by remote control to enable remote focusing.

The motor 1 is provided on one surface of the supporting member 10 and a position facing the one surface, and on the other surface and a position facing the other surface.
Limit switches 17a, 17b for turning off the power supply of No. 8
Are provided respectively. Therefore, when the support member 10 reaches the forward end or the backward end by the driving of the motor 18, the rotation of the motor 18 is stopped by the limit switches 17a and 17b, and the motor 18 continues to rotate to apply a load to the components. This is prevented.

As described above, the image pickup device 6 can be electrically moved by the motor 18.

At this time, when the photographing lens 3 is moved by electric power, a small size, high torque, and expensive motor are required due to the space limitation of the lens portion. However, according to the camera of the present embodiment, since the motor 18 can be installed in the body 1, the margin of space is increased,
Motor 1 that is cheaper than the case of moving the taking lens 3
8 can be used.

(Embodiment 3) FIG. 3 is a sectional view showing a main part of a camera according to still another embodiment of the present invention.

This embodiment has a structure in which the lens casing 2 is housed in the body 1. That is, as shown in FIG. 3, the casing fixing member 4 is provided inside the body 1, and the male screw portion 2 a formed on one side of the lens casing 2 is screwed to the female screw portion 4 a formed on the casing fixing member 4. It is supposed to do.

According to this, the length of the camera can be shortened only because the lens casing 2 does not project. As described above, the lens casing 2 has the body 1
Instead of not completely projecting from the above, it may be slightly projected.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, in the present embodiment, the taking lens 3 is attached to the lens casing 2 and the lens casing 2 is fixed to the body 1. However, if the taking lens 3 is not replaced, the taking lens 3 is taken. The lens 3 may be attached directly to the body 1.

Further, the movement of the image pickup device 6 does not use the gear mechanism as in the present embodiment, but as shown in FIG.
It is also possible to project the shaft 9 to the outside of the body 1 and manually move the shaft 9 in the axial direction. That is, as long as the image pickup device 6 is movable in parallel to the optical axis L of the taking lens 3, the image pickup device 6 can be moved by various mechanisms.

The first spur gear 14 and the second spur gear 14 in the second embodiment.
The gear ratio to the spur gear 15 is not limited to 6: 1, and the image sensor 6 can be moved at a desired speed by setting it to an arbitrary value.

Furthermore, the present invention can be applied to various cameras such as video cameras as long as the camera uses the image pickup device 6.

[0042]

The effects obtained by the typical ones of the inventions disclosed in this application will be briefly described as follows.

(1) That is, according to the focus adjusting technique of the present invention, the focus can be adjusted without moving the taking lens by moving the image pickup device in parallel with the optical axis of the taking lens. Therefore, a focus adjusting mechanism for moving the taking lens is not necessary.

(2) In addition, since the taking lens does not need a helicoid or the like, the effective diameter of the lens can be increased correspondingly, improving the imaging performance of the taking lens, distortion of the image, and improvement of peripheral light quantity. The effect such as can be expected. On the other hand, if the effective lens diameter is the same, the lens lens frame structure is simplified and the photographing lens has a smaller diameter.

(3) Since it is not necessary to move the taking lens, it is not necessary to consider the design around the lens when the taking lens is moved toward the outside of the camera body.

(4). When the photographic element is electrically moved by the motor, the motor can be installed in the body. Therefore, there is a space restriction for installing the motor such as when moving the photographic lens. Is released from. Therefore, it is possible to use not a small-sized and high-torque expensive motor, but a larger-sized but cheaper motor.
Further, as compared with the case where the focus of the photographing lens is manually adjusted, the focus can be adjusted with high accuracy.

(5). By preventing the lens casing from protruding from the body, the length of the camera can be shortened accordingly.

(6). Due to the above (1) and (4), the cost of the camera can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a camera according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a camera according to another embodiment of the present invention.

FIG. 3 is a sectional view showing a main part of a camera according to still another embodiment of the present invention.

FIG. 4 is a sectional view showing a camera according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2 Lens casing 2a Male screw part 3 Photography lens 4 Casing fixing member 4a Female screw part 5 Element casing 5a Shaft hole 6 Imaging device 7 Imaging device moving means 8 Rotating ring (rotation drive part) 8a Engagement groove 9 Shaft 10 Supporting member 11 Mounting board 12 Screw shaft 13 Slip coupling 14 First spur gear 15 Second spur gear 16 Shaft 17a Limit switch 17b Limit switch 18 Motor (rotation drive part) L Optical axis

Claims (6)

[Claims] 1. A photographic lens for capturing an image of a subject, an image sensor for receiving optical information from the photographic lens and converting the optical information into an electric signal, and moving the image sensor in parallel with an optical axis of the photographic lens. A camera having an image pickup device moving means. 2. The camera according to claim 1, wherein the image pickup element moving means is attached to one end of the shaft and a shaft which is reciprocated in parallel with the optical axis by rotation of a rotation drive section. A camera comprising a supporting member for supporting the element. 3. The camera according to claim 2, wherein the rotary drive unit is a rotary ring screwed to the shaft and manually rotated, or a motor that rotates a screw shaft screwed to the shaft. Characteristic camera. 4. The camera according to claim 1, 2 or 3, wherein the image pickup device is a charge coupled device. 5. The camera according to claim 1, wherein a casing fixing member is provided inside the body, the photographing lens is attached to the lens casing, the lens casing is fixed to the casing fixing member, and the lens casing is removed from the body. A camera characterized by not protruding. 6. A focus adjusting method for a camera, wherein a taking lens is fixed, and an image pickup device for receiving optical information from the taking lens is moved in parallel with an optical axis of the taking lens to perform focus adjustment.