JPH0320727B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens barrel with a built-in turret filter, and more particularly to a lens barrel with a built-in polarizing filter in which at least one of the holding filters is a polarizing filter.

A turret type filter has a turret type filter frame whose rotation center is outside the optical axis of the lens, and holds multiple filters that can be moved along the optical axis as the filter frame rotates. It is mainly built into short-focus interchangeable lenses.
There are no particular restrictions on the type of filter that can be held in this filter frame, but in conventional devices, the filter is fixed to the filter frame, so polarizing filters that need to be rotated during use cannot be held due to their nature. I stopped talking. In other words, the idea of incorporating a polarizing filter into a turret filter did not exist. Therefore, when using a polarizing filter, the only way to use it is to fit it into the filter frame at the front end of the lens and rotate it while visually checking the effect with the filter.Furthermore, the front element of the lens is moved far forward like an ultra-wide-angle lens. In some cases, lenses that protrude cannot be used.

The present invention reconsiders the conventional wisdom regarding such turret-type filters, that is, the fixed idea that the filter is fixed to a frame and cannot be rotated, and makes the turret-type filter hold the polarizing filter. This was created based on a new idea, in which at least one of the holding filters of the turret type filter frame is a polarizing filter, which can be rotated with respect to the filter frame, and this polarizing filter and the turret type filter It is characterized in that the frame can be rotated by operating a single filter operation ring and a conversion push button provided thereon.

The invention will now be described with reference to the illustrated embodiments. 1
1 is a fixed lens barrel attached to the camera body; 12 is a lens barrel screwed onto a focus ring 13 rotatably supported by the fixed lens barrel 11 via a helicoid 14; a front frame 15 is screwed onto the front end of the lens barrel; It is integrated into one body. Therefore, the lens barrel 12 and the front frame 15 move back and forth in the optical axis direction following the helicoid 14 as the focus ring 13 rotates.

The turret type filter frame 16 has a disk shape, and its center is rotatably supported by the lens barrel 12 by a shaft screw 17 at a position off the optical axis of the lens. A plurality of different types of filters 18 are supported on the circumferential surface of the turret type filter frame 16, which move along the optical axis as the turret type filter frame 16 rotates. One of the filters 18 is a polarizing filter 20 fixed to a polarizing filter frame 19,
Polarizing filter frame 19 is turret type filter frame 1
6, and a rotary engagement surface 21 is formed on the front surface of this polarizing filter frame 19.

The turret type filter frame 16 integrally has a filter conversion gear 22 in its center, and this filter conversion gear 22 is bored with radial interlocking grooves 23 of a number corresponding to the number of holding filters of the turret type filter frame 16. It is set up. This radial interlocking groove 23 meshes with an interlocking pin 25 of a filter conversion tube 24 rotatably fitted into the inner surface of the lens barrel 12, and as the filter conversion tube 24 rotates, the radial interlocking groove 23, that is, the turret type filter frame 16 is configured to rotate.

On the other hand, on the inner surface of the lens barrel 12, a polarizing filter rotary barrel 26 is supported so as to be rotatable around the optical axis and movable in the optical axis direction, and a rotary engagement surface 21 of the end surface of the polarizing filter frame 19 is attached to the rear end thereof. A cylindrical engagement surface 27 that can be engaged with is formed. The rotational engagement surfaces 21 and 27 are formed in a knurled shape in this embodiment, but any surface may be used as long as the rotation of the filter conversion tube 24 is transmitted to the polarizing filter frame 19 when the two contact each other. Alternatively, materials can also be used. Reference numerals 28 and 29 in FIG. 1 indicate a click ball and its biasing spring for stopping the turret type filter frame 16 with the filter 18 correctly positioned on the optical axis.

The filter converting tube 24 and the polarizing filter rotating tube 26 are respectively provided with interlocking pins 30 and 31 that protrude in the radial direction. The interlocking pins 30 and 31 are urged to protrude in the radial direction by compression springs 32 and 33, and can protrude to the outside of the lens barrel 12 through circumferential guide grooves 34 and 35 formed in the lens barrel 12, respectively. be. A single filter operating ring 40 is rotatably fitted into the lens barrel 12 in correspondence with the positions of the interlocking pins 31 and 32, and the interlocking pin 3 is attached to the inner surface of the ring 40.
an interlocking groove 4 in the optical axis direction into which both the operating ring 40 and the operating ring 40 can be fitted at different rotational positions;
1 is formed. That is, the circumferential guide groove 3
4 and 35 are positioned so that the interlocking pins 30 and 31 will not fit into the interlocking groove 41 at the same time. The filter operation ring 40 has an interlocking groove 41.
A conversion push button 42 is provided on the top and can be pressed from the outside, and this push button 42 has a release plate 43 that is located in the interlocking groove 41 and can come into contact with both the interlocking pins 30 and 31. are integrated. This pushbutton 42 only operates when the pushbutton is within the range of angle θ shown in FIGS. 2 and 3.
In other words, the pressing operation can be performed only when the polarizing filter 20 is rotating on the optical axis.
This regulation applies, for example, to the release plate 4 at angles other than the above angle θ.
This can be easily done if the lens barrel 3 is brought into contact with the regulating surface 44 on the outer surface of the lens barrel 12.

The circumferential guide groove 34 for the interlocking pin 30 of the filter conversion tube 24 is a complete circumferential groove, but the circumferential guide groove 35 for the polarizing filter rotation tube 26 is as shown in FIG. , circumferential groove 3
5a has an inclined guide groove 35b at the tip thereof, and when the polarizing filter rotating tube 26 is rotated, the polarizing filter rotating tube 26 moves in the optical axis direction by a length a of the inclined guide groove 35b in the optical axis direction. This length a is equal to the distance a (FIG. 1) until the engagement surface 27 of the polarizing filter rotating barrel 26 comes into contact with the rotating engagement surface 21 of the polarizing filter frame 19.

Therefore, as shown in FIG.
0 rotates, the filter conversion cylinder 24 rotates, and the turret type filter frame 16 rotates by the interlocking pin 25 and the radial interlocking groove 23, and the filter 18 located on the optical axis is replaced.
At this time, the interlocking pin 31 is pressed by the inner surface of the operating ring 40 and does not protrude outward from the lens barrel 12, so the interlocking pin 31 does not impede the rotation of the operating ring 40. The polarizing filter rotating barrel 26 does not rotate.

When the polarizing filter 20 is positioned on the optical axis by the above operation as shown in FIG. fall back. In this state, when the operating ring 40 is rotated by an angle θ clockwise in FIG. The interlocking pin 31 enters and the operation ring 40
and the polarizing filter rotary cylinder 26 are integrated in the rotation direction. Then, when the operating ring 40 is further rotated in the same direction, the interlocking pin 31 moves along the inclined guide groove 35b of the guide groove 35, so that the polarizing filter rotary cylinder 26 moves toward the polarizing filter frame 19 and its engagement surface 27 is brought into contact with the rotating engagement surface 21. Therefore, the subsequent rotation of the operating ring 40 causes the polarizing filter 20 to rotate. When converting to a filter other than the polarizing filter 20, the operation ring 40 may be rotated in the opposite direction to the above to return the push button 42 to the angle θ end in FIG. 2, and then the same operation as above may be performed.

In the above embodiment, the filter conversion tube 24, the polarizing filter rotation tube 26, and the filter operation ring 40 are fitted inside and outside the lens barrel 12, but depending on the lens structure, these may be fitted into a fixed lens barrel.
In short, these can be fitted into a wide range of "lens barrels".

As described above, according to the present invention, in a lens barrel with a built-in polarizing filter in which a polarizing filter is rotatably supported on a turret-type filter frame, a push button for converting the rotation of the turret-type filter frame itself and the rotation of the polarizing filter can be pressed. This can be done with a single filter operating ring. Therefore, there is no need to specially attach a polarizing filter that requires rotational operation to the front of the lens, and it is now possible to use a polarizing filter even with ultra-wide-angle lenses where the front lens element protrudes, and the polarizing filter can also be made with a small diameter. In addition to the basic effect of rotatably providing the polarizing filter in the turret type filter, which is the ability to reduce costs overall, there is also the effect of very good operability.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a lens barrel with a built-in turret type filter according to the present invention, and FIG.
A sectional view taken along the - line in the figure, and FIG. 3 is an expanded view of the cross section taken along the - line in FIG. 1. DESCRIPTION OF SYMBOLS 11... Fixed lens barrel, 12... Lens barrel, 18... Filter, 19... Polarizing filter frame, 20... Polarizing filter, 21... Rotating engagement surface, 22... Filter conversion gear, 24... Filter converting tube, 26... Polarizing filter rotation Cylinder, 27... engaging surface, 30, 31... interlocking pin,
32, 33... Compression spring, 34, 35... Circumferential guide groove, 35b... Inclined guide groove, 40... Filter operation ring, 41... Interlocking groove, 42... Conversion push button,
43...Release board.

Claims (1)

[Claims] 1. A turret-type filter frame that has a center of rotation outside the optical axis of the lens and moves a plurality of holding filters sequentially onto the optical axis as the lens rotates; At least one polarizing filter whose end face is a rotational engagement surface; the polarization filter has an engagement surface that can be moved toward and away from the rotational engagement surface of the polarization filter, and is rotatable and movable in the optical axis direction within the lens barrel. a polarizing filter rotary tube fitted therein; a filter conversion tube rotatably fitted in the lens barrel, which interlocks and rotates the turret type filter frame; an inner surface has an interlocking groove in the optical axis direction; a single filter operating ring rotatably fitted on the outside of the lens barrel;
an interlocking pin that is provided on the polarizing filter rotation tube and the filter conversion tube so as to protrude in the radial direction and is fitable into the interlocking groove of the filter operating ring through the circumferential guide groove of the lens barrel; a conversion pushbutton supported on the filter operating ring for retracting the pin from the interlocking groove into the circumferential guide groove against the protruding biasing force of the pin;
The circumferential guide groove of the interlocking pin of the polarizing filter rotating barrel moves it in the optical axis direction as the polarizing filter rotating barrel rotates, and causes its engagement surface to engage the rotating engagement surface of the polarizing filter. A lens barrel with a built-in polarizing filter that includes an inclined guide groove.