JPH07218798A - Lens barrel - Google Patents

Abstract

PURPOSE:To provide the space-saving, inexpensive lens barrel which can position lens frames mutually with high precision. CONSTITUTION:The lens-barrel is equipped with a two-group frame 2 which holds a two-group lens L2 for zooming and is moved forth and back in the optical axis direction by a feed screw 7 for two groups, a one-group frame 1 which holds a one-group lens L1 for focusing and is moved in the optical axis direction relatively to the two-group frame 2 by a feed screw 3 for one group, and an optical detecting means which optically detects the interval between the two-group frame 1 and one-group frame 1 by emitting infrared light by a 1st infrared LED 14, reflecting it by the one-group frame 1, and photodetecting it by a 1st PSD 15, and also optically detects the interval between the two-group frame 2 and a camera 11 by emitting infrared light by a 2nd infrared LED 12, reflecting the light by the camera 11, and photodetecting it by a 2nd PSD 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel, and more particularly to a lens barrel for detecting relative movement of a plurality of lens frames with high accuracy.

[0002]

2. Description of the Related Art Conventionally, a lens barrel having a plurality of lens frames which can be moved back and forth in the optical axis direction, has a means for improving the positional accuracy when relatively moving the plurality of lens frames. Various proposals have been made.

As an example of such a device, for example, Japanese Patent Publication No. 52-15226 discloses a first detecting means for detecting a focal length setting value and a second detecting means for detecting an image forming setting value. And a zoom focus type lens for fixing the image forming position. And, a sliding piece is used as the lens position detecting means,
It is disclosed that this means can be configured with a magnescale or the like.

As another example, JP-A-1-19772
No. 8 discloses a means for moving a variator lens group, a means for moving a compensator lens group, a focal length detecting means for detecting a focal length, a distance measuring means for detecting a distance to a subject, and the above focal length. A lens provided with a detecting means and a calculating means for calculating the position of a compensator lens group by a distance measuring means is disclosed. The lens position detecting means is composed of a known non-contact type position detector.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In Japanese Patent Laid-Open No. 226 and Japanese Patent Laid-Open No. 1-197728, it is difficult to obtain high detection accuracy in the lens position detecting means, and when using a magnescale or the like, in addition to this difficulty It also has a problem of high cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an inexpensive lens barrel capable of positioning the lens frames with high accuracy.

[0007]

In order to achieve the above object, a lens barrel according to the present invention is provided with a first lens frame which can be moved forward and backward in the optical axis direction, and the first lens frame. And a second lens frame that is relatively moved, and an optical detecting unit that optically detects a distance between the first lens frame and the second lens frame.

[0008]

The first lens frame advances and retreats in the optical axis direction, the second lens frame moves relative to the first lens frame, and the optical detecting means causes the first lens frame and the second lens frame to move. The distance to the frame is optically detected.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of the present invention, and FIG. 1 is a sectional view taken along the optical axis showing a main part when the lens barrel of the present embodiment is in a wide state. is there.

The first lens unit L1 for focusing is
It is held by the first group frame 1, and the first group frame 1 is screwed with the first group feed screw 3 and is movable in the optical axis direction.
Both ends of the first-group feed screw 3 are rotatably supported by the camera body 11, and a gear 4 is rotatably and integrally attached to an end portion on the rear side of the optical axis. The pinion gear 5 attached to the output shaft of the focusing motor 6 meshes with the pinion gear 5.

On the other hand, the second lens group L2 for zooming.
Is held by the second group frame 2, and the second group frame 2 is screwed with the second group feed screw 7 and is movable in the optical axis direction. Both ends of the second group feed screw 7 are attached to the camera body 1
1 is rotatably supported on the optical axis 1, and a gear 8 is attached to the end portion on the rear side of the optical axis so as to rotate integrally.
Meshes with a pinion gear 9 attached to the output shaft of the zooming motor 10.

On the side of the aperture 11a (on the rear side of the optical axis) of the second group frame 2, a second infrared LED 12 as a light emitting means, a second PSD (second position detecting device) 13 as a light receiving means, and condenser lenses 12a, 13a. Is attached, and the distance between the camera body 11 and the second lens group L2 can be measured by performing ratio calculation processing.

The object side of the second group frame 2 (front side of the optical axis)
A unit of a first infrared LED 14 which is a light emitting means, a first PSD (first position detecting device) 15 which is a light receiving means, and condenser lenses 14a, 15a is attached to the
The distance between the second group lens L2 and the first group lens L1 can be measured by performing a ratio calculation process. The position measurement accuracy at this time is, for example, about ± 5 μm.

The focusing motor 6, zooming motor 10, first infrared LED 14, second infrared L
The ED 12, the first PSD 15, and the second PSD 13 are connected to a CPU 18, as shown in FIG. 2, and an AF distance measuring unit 19 that measures the distance to the subject is connected to the CPU 18.

Next, the operation of such an embodiment will be described. When the zoom switch (not shown) is operated to the tele side in the wide state as shown in FIG. 1, the signal is input to the CPU 18, the signal is output from the CPU 18 to the zooming motor 10, and the pinion gear 9 and the gear 8 are passed. The second group feed screw 7 starts to rotate. Then, the second group frame 2 holding the second group lens group L2 starts to move straight in the optical axis direction.

Then, the second infrared LED 12 starts to emit light at a constant time interval. The infrared light emitted from the second infrared LED 12 and emitted through the condenser lens 12a is reflected by the surface of the camera body 11 near the aperture 11a on the front side of the optical axis, and passes through the condenser lens 13a. 2nd P
It is incident on SD13. The position of the second lens group L2 is transmitted to the CPU 18 at a constant time interval by the change of the barycentric position of the received light intensity distribution by the second PSD 13.

Then, a signal is output from the CPU 18 to the focusing motor 6, and the pinion gear 5 and the gear 4 are
The feed screw 3 for the first group starts rotating via the. And 1
The first group frame 1 holding the group lens group L1 starts moving along the optical axis direction. That is, the first lens group L1 operates after the zoom movement of the second lens group L2.

Next, when the operation of the zoom switch is stopped,
A stop signal is output from the CPU 18 to the zooming motor 10. As a result, when the second group frame 2 stops, the second infrared L
The ED 12 emits light and is detected by the second PSD 13, and the absolute position of the second lens unit L2 (position with respect to the camera body 11) is C
Tell UP18.

The CPU 18 controls the position of the first lens group L1 corresponding to the position of the second lens group L2 (for example, the focus is ∞).
(The position before the current position) is calculated, and 1 is calculated at that position.
The group lens L1 is controlled to stop.

In order to detect the position of the first group lens L1, the first infrared LED 14 is caused to emit light and the condenser lens 14a is formed.
And then reflected by the first group frame 1, and the condenser lens 1
It is incident on the first PSD 15 through 5a and detected.

The position of the first lens group L1 with respect to the second lens group L2 is accurately obtained by the change of the center of gravity position of the received light intensity distribution by the first PSD 15, and the focusing motor 6 is stopped when the target position is reached.

After the focusing motor 6 is stopped,
The first infrared LED 14 is caused to emit light again, and the position of the first group lens L1 with respect to the second group lens L2 is measured. At this time, if the first lens group L1 is out of the target range, the amount of deviation from the target position is calculated, and the CPU 18 sends a signal to the focusing motor 6 to drive it by the amount of the first lens group L1. Move it back and forth slightly and put it in the desired position.

Here, the above-mentioned "position before the position where the focus is in the ∞ state" may be a position before the position where the focus is in the ∞ state by a certain value, and the focusing motor 6 is stopped. It suffices to measure the distance between the rear lens group L1 and the second lens group L2 and store the value.

Next, when a first release (not shown) is pressed, the AF distance measuring unit 19 measures the distance to the subject and the obtained subject distance information is sent to the CPU 18. Then, the first lens group L corresponding to the subject distance
The CPU 18 calculates the feed amount of 1.

Then, the focal length information is obtained from the absolute position information of the second lens group L2, and the information is calculated together with the subject distance information, and the distance between the first lens group L1 and the second lens group L2 is determined as the target. To do.

Next, a signal is sent from the CPU 18 to the focusing motor 6, and the first group feed screw 3 advances the first group lens L1 in the optical axis direction. Meanwhile, the first infrared LE
D14 is made to emit light at a constant time interval, and the first PSD15
Thus, the position of the first lens unit L1 with respect to the second lens unit L2 is accurately obtained, and the focusing motor 6 is stopped when the target position is reached.

After the stop, the first infrared LED 14 is caused to emit light again to measure the position of the first lens group L1 with respect to the second lens group L2. If the first lens group L1 is out of the target range, the CPU 18 compares the measurement result with the target position to calculate the amount of deviation, and sends a signal to the focusing motor 6 to generate an amount corresponding to the amount of deviation. It is driven to move the first lens group L1 back and forth by a small amount to bring it to the target position. This operation is repeated until the first lens group L1 reaches the target position.

When the 2nd release is pressed, the shutter (not shown) is opened and closed to expose the film, and the photographing is completed.

According to such an embodiment, there is an advantage that the stop position of the lens can be accurately detected, and as a result, the accuracy of focusing can be further improved. Further, by using the non-contact optical detection method using the infrared LED and the PSD, the space required for detecting the lens position can be small and the cost can be reduced. Furthermore, since the inside of the lens barrel is a dark box and it is not necessary to worry about external light noise, this method is particularly advantageous.

In addition, the conventional incremental counting method, that is, the method of counting the movement of the lens frame with a photo interrupter or the like, causes a count deviation with respect to the actual lens position by repeating the zoom operation. However, since the absolute position of the lens frame holding the zoom lens with respect to the camera body is detected every time the zoom operation is performed, the means of the present embodiment does not cause such a shift. The accuracy is high. Further, since the infrared LED is used as the optical detection method, there is no concern that the film is exposed by the detection light.

FIGS. 4 and 5 show a second embodiment of the present invention. In the second embodiment, parts having the same functions as those of the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted. Only different points will be mainly described.

In the first embodiment described above, the first lens group L1,
While the second group lens L2 is driven by the independent motors 6 and 10, in the present embodiment, the output of one motor 21 is switched by the clutch switching means, so that the first group lens L1 and the second group lens L2. L2 is driven.

That is, the pinion gear 22 which is attached to the output shaft of the motor 21 and is slightly long in the axial direction meshes with the gear 23, and the gear 23 is provided with another gear 27 via a shaft 24 extending in the optical axis direction. It is integrated with the rotation. The shaft 24 is moved in the optical axis direction by a solenoid plunger 25 provided in the middle of the shaft 24.

The gear 23 meshes with the gear 26 when the shaft 24 is moved to the rear side of the optical axis by the solenoid plunger 25, and the gear 26 of the second group feed screw 7 is engaged. It meshes with a gear 8 provided at the end.

On the other hand, when the shaft 24 is moved to the front side of the optical axis by the solenoid plunger 25, the gear 27 meshes with the gear 4 provided at the end of the first group feed screw 3. There is.

Further, the motor 21 and the plunger 25
5, is connected to the CPU 18 together with the first infrared LED 14, the second infrared LED 12, the first PSD 15, the second PSD 13, and the AF distance measuring unit 19.

In the above description, the clutch switching means is configured to switch the gears by moving the shaft 24 having the gears 23 and 27 at both ends using a solenoid plunger, but the invention is not limited to this. Instead, any means may be used as long as it can switch and transmit the power of the motor 21.

According to the second embodiment, the same effect as that of the first embodiment can be obtained, and the number of motors serving as drive sources can be reduced, so that the structure is simpler and the cost is reduced. It has the advantage of being able to

FIGS. 6 and 7 show a third embodiment of the present invention. In the third embodiment, the above-mentioned first,
Portions having the same functions as those of the second embodiment are designated by the same reference numerals and the description thereof will be omitted. Only different points will be mainly described.

In this embodiment, the first infrared LED 14 and the condenser lens 14a are provided on the front surface of the second group frame 2 on the optical axis side, and the second infrared LED 12 and the condenser lens are provided on the rear surface side of the optical axis. 12a are provided respectively, and the first group LE 1 is provided in the first group frame 1.
The PSD 15 is arranged so as to face the D14, and the second infrared LE is provided on the camera body 11 near the aperture 11a.
The PSD 13 is arranged so as to face the D 12.

Further, in this embodiment, the intensity of the infrared light emitted from the second infrared LED 12 through the condenser lens 12a is controlled by the second PSD1 by the light intensity integration processing.
The absolute position of the second lens group L2 as determined by 3 (the camera body 1
(Position relative to 1), and the intensity of the infrared light emitted from the first infrared LED 14 via the condenser lens 14a is discriminated by the first PSD 15 by the light amount integration processing, and the first group lens L1 and the second group L2. The distance between the lenses L2 is measured (see FIG. 7).

In the third embodiment, the infrared LED 1
2 and 14 are attached to the second group frame 2, but the infrared LED 1
The positions for attaching 2, 14 and the positions for attaching the PSDs 13, 15 may be reversed.

The method of controlling the first lens group L1 and the second lens group L2 according to this embodiment is almost the same as that of the first embodiment.

According to the third embodiment, the same effects as those of the first and second embodiments are provided.

8 to 10 show a fourth embodiment of the present invention. In the fourth embodiment, portions having the same functions as those of the first to third embodiments described above are designated by the same reference numerals, and the description thereof will be omitted. Only different points will be mainly described.

The fourth embodiment is different from the above-mentioned first to third embodiments in that the first group lens L1 is used for zooming and the second group lens L2 is used for focusing, so-called rear focus type zoom. It is a lens barrel.

The first group frame 41 for holding the first group lens L1 is
A cylindrical first group frame main body 41a having a size that covers the outer peripheral side of the second group lens L2, an inner flange 41b provided at the front end of the first group frame main body 41a, and the first group frame main body 41a.
It has an inner flange 41c provided at the rear end portion and a holding portion 41d for holding the first-group lens L1, and a protrusion 41e is provided from the rear end portion of the outer peripheral surface to attach the first-group feed screw 3. It is screwed.

The gear 4 provided at the rear end of the first group feed screw 3 meshes with the pinion gear 9 attached to the output shaft of the zooming motor 40, that is,
In this embodiment, zooming is performed by moving the first lens unit L1 back and forth in the optical axis direction.

The second group feed screw 7 screwed into the second group frame 2 is meshed with the pinion gear 5 attached to the output shaft of the focusing motor 46 by the gear 8 at the front end thereof. In this way, focusing is performed by moving the second group lens L2 back and forth in the optical axis direction.

On the surface of the second group frame 2 on the front side of the optical axis, the second infrared rays L
The ED 12 and the condensing lens 12a further include the condensing lens 13
a and the second PSD 13 are attached.

The first infrared LED 14 is provided on the surface of the inner flange 41c on the rear end side of the first group frame 41 on the rear side of the optical axis.
And the condensing lens 14a, and the condensing lens 15a and the first
PSD15 is attached.

Next, the operation of such an embodiment will be described. When a zoom button (not shown) is pressed, a signal is output from the CPU 18 and the zooming motor 40 starts driving,
Feed screw 3 for 1st group via pinion gear 9 and gear 4
Move along the optical axis.

Next, the first infrared LED 14 starts emitting infrared light at regular time intervals. The infrared light is emitted through the condenser lens 14a, is reflected by the camera body 11 near the aperture 11a, and is incident on the first PSD 15.
The position of the first group frame 41 is measured by measuring the position of the center of gravity of the received light intensity distribution with the first PSD 15, and the CPU 18
Send the result to.

The CPU 18 receiving this signal causes the second group frame 2
A signal for driving the focusing motor 46 is output so that the position of (1) corresponds to the position of the first group frame 41. When the second group frame 2 is driven by the focusing motor 46 that receives this signal, the second infrared LED 12 emits infrared light.

This infrared light is reflected by the surface on the optical axis rear side of the holding portion 41d holding the first group lens L1 and then the second PSD.
The second PSD 13 is made incident, and the position of the center of gravity of the received light intensity distribution is measured by this second PSD 13 to measure the distance between the first group lens L1 and the second group lens L2.

In response to this measurement result, the CPU 18 calculates the position of the second lens group L2 (the position before the position where the focus is in the ∞ state) corresponding to the position of the first lens group L1, and stops at that position. To control.

Next, when the 1st release (not shown) is pressed, the distance to the object is measured by the AF distance measuring unit 19, and the CPU 18 calculates the amount of extension of the second lens group L2 corresponding to this distance measuring result. That is, the CPU 18
Obtains the focal length information from the absolute position information of the first lens group L1 and calculates it together with the subject distance information from the AF distance measuring unit 19 to determine the distance between the desired first lens group L1 and the second lens group L2. To do.

Next, the CPU 18 sends a signal to the focusing motor 46 to move the second group lens L2 forward and backward in the optical axis direction via the second group feed screw 7. During that time, the second infrared LED 12 is caused to emit light at a fixed time interval, and the position of the second group lens L2 with respect to the first group lens L1 is accurately obtained by the second PSD 13 that has received the reflected infrared light.

Then, the focusing motor 46 is stopped when the second lens group L2 reaches the target position. After stopping, let the second infrared LED 12 emit light again, and
The distance between the group lens L1 and the second group lens L2 is measured. If the second lens unit L2 is out of the target range, the CPU1
8 calculates the amount of deviation from the target position, sends a signal to the focusing motor 46 to drive it, and causes the second group lens L2
Move it back and forth slightly and put it in the desired position. This operation is repeated until the target position is reached.

When the 2nd release is pressed, a shutter (not shown) is opened and closed to expose the film, and the photographing is completed.

According to the fourth embodiment, the same effects as those of the first to third embodiments are provided, and the present invention can be easily applied to the rear focus type zoom lens. You can see that

11 and 12 show a fifth embodiment of the present invention. In the fifth embodiment, portions having the same functions as those of the above-described first to fourth embodiments are designated by the same reference numerals and description thereof will be omitted, and only different points will be mainly described.

This embodiment is a type in which the infrared LED and the condenser lens are integrated.

That is, as shown in the figure, an infrared LED 51 is provided on the peripheral surface of the second group frame 2, and the infrared LED 5
Infrared light is emitted from the outer diameter direction 1 and enters the first prism 52. This first prism 5
As shown in FIG. 12, 2 is approximately 4 with respect to the incident surface.
It has a surface inclined at 5 degrees, and this surface is a half mirror surface 52a. This half mirror surface 5
The infrared light reflected to the rear side of the optical axis by 2a is reflected by the aperture 11
The light is reflected by the surface of the camera body 11 near the front side of the optical axis.

On the other hand, the infrared light transmitted through the half mirror surface 52a enters the second prism 53 and is reflected toward the front side of the optical axis.

A condenser lens 54 is arranged near the prisms 52 and 53, and the first PSD 15 is provided on the rear side so as to sandwich the condenser lens 54 substantially in the optical axis direction.
However, the second PSD 13 is disposed on the front side.

That is, the infrared light emitted from the infrared LED 51 and reflected by the half mirror surface 52a of the first prism 52 is reflected by the camera body 11 and then enters the second PSD 13 through the condenser lens 54. It is like this.

Further, the infrared light which has passed through the half mirror surface 52a and is incident on the second prism 53 is reflected by the reflecting surface thereof and is then emitted to the front side of the optical axis, and further, the optical axis of the first group frame 1 The light is reflected by the rear surface and is incident on the first PSD 15 through the condenser lens 54.

In the lens barrel of this embodiment having such a structure, when the infrared LED 51 is made to emit light once, the distance between the second lens group L2 and the first lens group L1 and the distance between the second lens group L2 and the camera body 11 are changed. , Can be measured at the same time.

Thus, in this embodiment, the half mirror surface 52
With the prisms 52 and 53 sandwiching a, the infrared LED 51
Is divided into two directions and is incident on the first PSD 15 and the second PSD 13 through one condenser lens 54 to measure the positions of the first group lens L1 and the second group lens L2 with respect to the camera body 11.

According to the fifth embodiment, the operation and effect are almost the same as those of the first to fourth embodiments, and the cost can be further reduced by such a device. There is.

13 and 14 show the sixth embodiment of the present invention. In the sixth embodiment, parts having the same functions as those of the first to fifth embodiments described above are designated by the same reference numerals, and the description thereof will be omitted. Only different points will be mainly described.

The present embodiment relates to a monofocal lens barrel instead of the zoom lens barrel as in the above-mentioned respective embodiments.

The lens 61 is held by the lens frame 62. A feed screw 63 arranged parallel to the optical axis is screwed into the lens frame 62, and both ends of the feed screw 63 are pivotally supported by the camera body 11. A gear 64 is provided at the end of the feed screw 63 on the rear side of the optical axis and meshes with a pinion gear 65 attached to the output shaft of a motor 66.

An infrared LED 67 and a condenser lens 67a are attached to the surface of the lens frame 62 on the rear side of the optical axis.
Further, a PSD 68 and a condenser lens 68a are provided.

Next, the operation of this embodiment will be described. When the 1st release (not shown) is pressed, the distance to the subject is measured by the AF distance measuring unit 19, and the lens 61
The CPU 18 calculates the amount of feeding. Next, CPU1
A signal is sent from 8 to the motor 66 to drive the motor 66, the feed screw 63 rotates via the pinion gear 65 and the gear 64, and the lens frame 62 moves along the optical axis direction.

Next, the infrared LED 67 emits light at a constant time interval and is emitted through the condenser lens 67a. This infrared light is reflected by the surface of the camera body 11 near the aperture 11a on the front side of the optical axis, and passes through the condenser lens 68a for PS.
It is incident on D68.

The PSD 68 accurately determines the position of the lens 61 with respect to the camera body 11 based on the change in the center of gravity of the received light intensity distribution, and sends the result to the CPU 18. Then, the CPU 18 sends a signal to the motor 66 when the target position is reached, and stops the motor 66.

After the motor 66 is stopped, the infrared LED 67 is caused to emit light again to measure the position of the lens 61 with respect to the camera body 11. If it is outside the target range, the CPU 18 calculates the amount of deviation from the target position, sends a signal to the motor 66 to drive the motor 66 by an amount corresponding to this amount of deviation, and slightly moves the lens 61 back and forth. Let me put it in the target position. This operation is repeated until the lens 61 reaches the target position.

When the 2nd release is pressed, a shutter (not shown) is opened and closed to expose the film, and the photographing is completed.

According to the sixth embodiment, the same effects as those of the above-mentioned first to fifth embodiments are obtained, and it is understood that the present invention can be easily applied to a single focus lens.

In the above-mentioned first to fifth embodiments, 2
Although a zoom lens having a group configuration has been described, it goes without saying that the present invention can be applied to a zoom lens having two or more groups.

[Additional Notes] According to the embodiment of the present invention as described in detail above, the following constitution can be obtained. That is, (1) a first lens frame that can be moved back and forth in the optical axis direction, a second lens frame that is relatively moved with respect to the first lens frame, the first lens frame and the second lens frame. An optical detecting means for optically detecting a distance between the lens barrel and the lens frame, and the optical detecting means is composed of an IRLED and a PSD.

(2) The first optical element which can be moved back and forth in the optical axis direction.
And the second frame that is moved relative to the first frame.
And an optical detecting means for optically detecting the distance between the first and second lens frames, the optical detecting means having a ratio calculating means. Characteristic lens barrel.

(3) First that can be moved back and forth in the optical axis direction
And the second frame that is moved relative to the first frame.
And an optical detecting means for optically detecting a distance between the first and second lens frames, the optical detecting means having a light quantity integrating means. Characteristic lens barrel.

(4) First movable in the optical axis direction
And the second frame that is moved relative to the first frame.
And an optical detection means for optically detecting the distance between the first and second lens frames, the first lens frame holding a variator lens group. A lens characterized in that the lens frame holding the compensator lens group is moved back and forth in the optical axis direction based on the focal length information obtained by detecting the distance between the first lens frame and the second lens frame. Lens barrel.

(5) The lens barrel according to appendix 4, wherein the variator lens group and the compensator lens group are alternately moved in the optical axis direction.

(6) A photographing optical system which is a monofocal lens group, and an optical detecting means for optically detecting the position of the lens group are provided, and based on the object distance information,
A lens barrel for calculating a position of the lens group with respect to an image forming plane of a photographing optical system.

(7) The lens barrel as set forth in appendix 6, wherein the optical detecting means has a light emitting means and a light receiving means.

(8) The optical detecting means is an IRLED
7. The lens barrel according to appendix 6, comprising:

(9) The lens barrel according to appendix 6, wherein the optical detecting means has a ratio calculating means.

(10) The lens barrel according to appendix 6, wherein the optical detecting means has a light quantity integrating means.

[0093]

As described above, according to the present invention, it is possible to provide an inexpensive lens barrel in which the lens frames can be positioned with high accuracy.

[Brief description of drawings]

FIG. 1 is a sectional view taken along the optical axis showing a main part when a lens barrel of a first embodiment of the present invention is in a wide state.

FIG. 2 is a block diagram showing a main part of an electric circuit of the lens barrel of the first embodiment.

FIG. 3 is a sectional view taken along the optical axis showing a main part when the lens barrel of the first embodiment is in the tele state.

FIG. 4 is a sectional view taken along the optical axis showing a main part of a lens barrel of a second embodiment of the present invention.

FIG. 5 is a block diagram showing a main part of an electric circuit of the lens barrel of the second embodiment.

FIG. 6 is a sectional view taken along the optical axis showing a main part of a lens barrel of a third embodiment of the present invention.

FIG. 7 is a block diagram showing a main part of an electric circuit of the lens barrel of the third embodiment.

FIG. 8 is a sectional view taken along the optical axis showing a main part when the lens barrel of a fourth embodiment of the present invention is in a wide state.

FIG. 9 is a block diagram showing a main part of an electric circuit of the lens barrel of the fourth embodiment.

FIG. 10 is a sectional view taken along the optical axis showing a main part when the lens barrel of the fourth embodiment is in the telephoto state.

FIG. 11 is a sectional view taken along the optical axis showing a main part of a lens barrel of a fifth embodiment of the present invention.

FIG. 12 is a perspective view showing an infrared LED, a first prism, and a second prism of the fifth embodiment.

FIG. 13 is a sectional view taken along the optical axis showing a main part of a lens barrel of a sixth embodiment of the present invention.

FIG. 14 is a block diagram showing a main part of an electric circuit of the lens barrel of the sixth embodiment.

[Explanation of symbols]

 1 ... 1 group frame 2 ... 2 group frame 11 ... Camera body 12 ... 2nd infrared LED 13 ... 2nd PSD 14 ... 1st infrared LED 15 ... 1st PSD 41 ... 1 group frame 51 ... Infrared LED 61 ... Lens 62 ... Mirror frame 67 ... Infrared LED 68 ... PSD L1 ... First group lens L2 ... Second group lens

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03B 3/00 A

Claims (2)

[Claims] 1. A first lens frame which is movable in the optical axis direction, a second lens frame which is relatively moved with respect to the first lens frame, the first lens frame and the second lens frame. A lens barrel comprising: an optical detection unit that optically detects a distance between the lens barrel and the lens frame. 2. The lens barrel according to claim 1, wherein the optical detecting means has a light emitting means and a light receiving means.