JPS63169623A - Blade for lens shutter - Google Patents

Abstract

PURPOSE:To drives a lens shutter which varies in aperture diameter by using at least two blades at a high speed by setting the gap between adjacent blades in an optical-axis direction so that they do not bring into contact each other, and providing a shielding projection part which reduces the influence of diffracted light to the periphery of a blade. CONSTITUTION:The 1st and 2nd sector blades 1 and 2 which open and close an optical system optical path 4 are provided between a photographic lens 3 and a solid-state image pickup element 8 such as a CCD, and the fulcrum of rotation of their base parts are supported pivotally on support shafts 5 and 6 projecting inward from a fixed member 7 through a driving pin 9 and a driving member 10. At this time, oblong holes 1a and 2a for opening and closing are bored in the base parts and swung by the pin 9 and member 10, and the gap between the blades 1 and 2 in the direction of the optical axis is set to about 1mm. Further, the projection part 11 for cutting off diffracted light which closes the gap is provided to the periphery of the inner edge part of the front surface of the blade 2 so as to cut off light traveling round from the gap. Thus, frictional load resistance is reduced and the high-speed driving is enabled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a lens shutter blade, and more particularly to a lens shutter blade used in a light shielding mechanism of an electronic still camera or video camera using a solid-state imaging probe. It is something.

[Prior Art] As is well known, light shielding mechanisms such as apertures and shutters that use two or more light shielding blades (sectors) have conventionally
It is used in cameras that use silver halide film, but in this case, especially in the shack mechanism, the film becomes sensitive to even the slightest leaked light, so adjacent blades are closely spaced in the optical axis direction. It was necessary to allow no light to pass through when it was fully opened.

[Problems to be Solved by the Invention] Therefore, in the conventional light-shielding mechanism using light-shielding blades, the blades open and close while being in close contact with each other, resulting in a large frictional load, making it difficult to use a high-speed blade-type lens shutter. This was an obstacle to achieving this goal.

In addition, a single-blade guillotine-type shutter can be considered as a means to prevent the frictional load from increasing due to close contact between the blades and to reduce the speed of the high-speed shutter by 1%. If you use this guillotine type shutter, the sliding resistance between the blades will of course be eliminated, or the opening will be done with just one blade.

Disadvantages include that the movement stroke in the full opening operation becomes large, which takes time, and that the space in the radial direction perpendicular to the optical axis becomes large.

On the other hand, when a shutter mechanism based on the light shielding mechanism described above is adopted in an electronic still camera or video camera that uses a solid-state imaging element such as a CCD instead of a silver-halide film, the solid-state imaging element itself is made of silver-halide film. Since there is no risk of chemical changes occurring over time due to exposure, there is no need to completely block light when the shutter is closed at the end of exposure. Also C
The solid-state imaging device itself, such as the OD, has a function to turn on and off the exposure operation, and there is no need to remain exposed for a long time to the reflected light when the shutter is open, so when the shutter is open, However, it does not need to be completely shielded from light.

The present invention has been made in view of these points, and the blades are spaced apart in the optical axis direction to such an extent that they do not touch each other, thereby eliminating sliding resistance and enabling high-speed drive. To provide blades for lens shutters.

[Means and Works for Solving the Problems] 110 The present invention provides a solid-state image sensing device.Secondly, in order to block the transmitted light flux of the optical system that forms the optical image of the object, at least two blades are provided. In the light shielding mechanism for varying the aperture IY using the light shielding mechanism, the interval between adjacent blades in the optical axis direction is set to such an extent that they do not come into contact with each other.

[Example] The present invention will be explained below with reference to illustrated embodiments.

1 to 3 show a first embodiment of the present invention, in which the present invention is applied to a well-known vario-type shutter consisting of two sickle-shaped sector blades. .

The sector blades 1 and 2 of the shutter are each pivotably pivoted so that the rotational fulcrum at the base thereof is pivoted to a support shaft 5.6 which is equivalent to the fixed member 7. It is disposed between a solid-state image pickup device 8 such as a CCD on which a light image is formed, and opens and closes an optical system optical path 4 including an L photographing lens 3. The above sector blade 1,
2 performs opening/closing operations by swinging a driving member 10 of a driving bin 9 that is commonly inserted through opening/closing elongated holes 1a, 2a bored in each of its bases.

When arranging the sector blades 1.2 as described above, in the present invention, the distance between the sector blades 1 and 2 in the optical axis direction is set to such an extent that they do not contact each other, for example, a distance of about 1 mm. Attach it to the immovable member 7 in this manner.

With this configuration, the blades operate without contacting each other, so there is no sliding resistance and high-speed driving can be performed. However, light wraps around through the gaps between the blades and enters the optical path. In order to prevent this diffracted light, the overlapping portion of the blades in the optical axis direction may be increased in the fully open state. In addition, around the inner edge of the front surface of the sector blade 2,
A diffracted light blocking protrusion 11 may be provided to prevent gaps between the blades in the optical axis direction and to reduce the influence of diffracted light.

This diffracted light blocking protrusion 11 is formed by metal etching, plastic molding, or the like.

The protrusion 11 is thus provided to prevent diffracted light. In this case, even if adjacent blades come into contact with each other due to vibration or stirring of the blades, the contact area is small, so the negative friction can be sufficiently reduced.

In addition, the sector blades themselves are made thinner to reduce weight for high-speed drive, and when the blades are in use with increased vibration or turbulence, this protrusion 11 is actively used to prevent vibrations and turbulence, thereby reducing the frictional load. vibration.

It is possible to reduce irritation. Further, the surface of the protrusion can be treated with carbon treatment (polyester vanes), Teflon coating, carbon nitride, silicon nitride, titanium nitride, etc. to reduce the frictional load.

FIG. 4 shows another example of the sector blade support means in the above embodiment. In the above embodiment, sector blade 1.
The bases of 2 were attached to both sides of the support part 7a (see Fig. 3) using the protruding support part of the immovable member 7 as a spacer for forming a gap, but as shown in Fig. supporting portions 7b extending opposite each other in an L-shape;
The support shafts 5 and 6 may be fixed to the support shafts 7c, and the respective bases of the sector blades 1.2 may be pivotably connected to the support shafts 5 and 6.

5 and 6 (A) and (B) show a second embodiment of the present invention, in which the present invention is applied to a lens shutter type shutter consisting of a large number of sector blades. It was applied.

This shutter includes a round tray-shaped case body 12 having an aperture 12a in the center for transmitting a lens beam, and a sector blade 1 which is rotatably disposed within the case body 12.
Drive bins 14a to 14n that open and close 3a to 13n
, a drive member 15 for reciprocating the arrow wheel 14, support shafts 16a to 16n for supporting sector blades fixed to the end surface of the peripheral wall of the case body 12, and each support shaft 16a. Sector blades 13a to 13n are disposed with their bases rotatably pivoted to . A spacer member 18 is fitted to each support shaft to create a gap to the extent that the sector blades do not contact each other in the optical axis direction, and a diffracted light beam is provided around the front side of a part or all of the sector blades on the rear side. It is composed of a protrusion 19 for blocking. The other configurations are the same as those of the first embodiment.

Even with this configuration, the same functions and effects as those of the first embodiment can be achieved.

[Effects of the Invention] As described above, according to the present invention, since the adjacent blades open and close without contacting each other, there is no frictional load resistance at all, and the electronic still camera can be driven at high speed. A blade for a lens shutter for a video camera can be provided.

[Brief explanation of the drawing]

1 is a front view of a lens shutter blade showing a first embodiment of the present invention; FIG. 2 is a front view of the lens shutter blade shown in FIG. 1 in an open state; FIG. Figures 1 and 2 are diagrams showing how the lens shank blades are arranged in the optical path of the optical system, Figure 4 is an enlarged cross-sectional view of main parts showing another example of how the sector blades are supported, and Figure 5 is: 6(A) and 6(B) are front views respectively showing the opened and closed states of the lens shutter blade shown in FIG. 5. .

Claims (2)

[Claims] (1) In a lens shutter that uses at least two blades to vary the aperture diameter in order to block the transmitted light flux of the optical system that forms the optical image of the subject on the solid-state image sensor, the distance between adjacent blades is A lens shutter blade characterized in that the blades are spaced apart in the optical axis direction to such an extent that they do not touch each other. (2) The blade for a lens shutter according to claim 1, further comprising a protrusion for blocking diffracted light in order to reduce the influence of diffracted light on the periphery of the blade.