JPH0520020U - Interchangeable lens diaphragm device - Google Patents

Abstract

(57) [Summary] [Object] To provide an interchangeable lens diaphragm device that does not cause an error from a reference setting curve without changing the conventional diaphragm control system between the camera body and the interchangeable lens. A converting means is installed between a first aperture stop lever and a second aperture stop lever, and the conversion means is interlocked with the displacement amount of the second aperture stop lever with respect to the aperture stage number, and the first means for the aperture stage number. The displacement amount of the narrowing lever is controlled so as to be proportionally changed in the region near the first stage of the number of diaphragm stages and is equally changed in the larger region thereafter. [Effect] There is no error in the relationship between the stroke of the second aperture lever and the number of aperture stages. It is not necessary to change the conventional diaphragm control system between the camera body and the interchangeable lens, and it is possible to eliminate the error with respect to the reference setting curve in the relationship between the stroke of the first diaphragm lever and the number of diaphragm steps.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a diaphragm device for a photographic interchangeable lens.

[0002]

[Prior Art]

 A conventional diaphragm device for a general photographic interchangeable lens has a structure as shown in FIG. 3, for example. The example shown in FIG. 3 shows a zoom lens in which both the aperture diameter and the aperture position change in association with zooming. In the figure, 1 is a diaphragm blade, and a predetermined number of them are combined, and each of them has a pin 1b fitted in a hole of a fixed ring (not shown) and a pin 1a fitted in a cam groove 2a of the diaphragm blade drive plate 2. It is provided. The diaphragm blade drive plate 2 is rotatable around the optical axis and has a protrusion 2b on the outer circumference.

As shown by the solid line C in FIG. 4, the shape of the cam groove 2a of the diaphragm blade drive plate 2 is such that, in the region x near the first stage of the narrowing down, the first narrowing lever 3 which will be described later responds to changes in the number of narrowing stages. In the region y after that, the first throttle lever 3 is displaced isometrically with respect to the change in the number of aperture steps, and even at the boundary between the region near the first stage and the region after that. The first throttle lever is determined so as to be smoothly displaced, and this boundary point is set so that the number of throttle steps is around one.

The first aperture stop lever 3 engages with the aperture setting lever 4 on the camera side and has a disc portion 3a (a part of which is omitted in FIG. 3). The disc portion 3a is a fixed lens barrel (not shown). It is rotatably supported around the optical axis. The first throttle lever 3 has a transmission pin 5 and is urged downward in the drawing by a spring 6. The second squeezing lever 7 is rotatably provided about a shaft 8, has an arm 9 extending in the optical axis direction at one end, has a groove 7a into which the transmission pin 5 is fitted, and has a spring 6 The spring 10 having a small biasing force is biased upward in the figure, that is, clockwise. The arm 9 is formed with an inclined groove 9a that engages with the projection 2b of the diaphragm blade drive plate 2, and a sloped surface 9b having a height gradient of γ with respect to the stroke L in the optical axis direction.

A lens unit (not shown) is provided with a diaphragm unit including a diaphragm blade 1 and a diaphragm blade drive plate 2, and the projection 11 slides in parallel with the optical axis by zooming together with the lens group and the diaphragm unit. The protrusion 11 is in contact with the sloped surface 9b. The state of FIG. 3 shows the state in which the zoom lens is in the telephoto position, and the transmission pin 5 is located at the lowest point of the groove 7a of the second aperture lever 7.

When the aperture value for obtaining the proper exposure based on the subject brightness, the shutter speed, the film sensitivity, etc. is determined by the photometry circuit of the camera at the time of shooting, the amount corresponding to the value is determined immediately before the shutter front curtain travels. Only when the aperture setting lever 4 moves downward (in the direction of the arrow) in the figure, the first aperture lever 3 is rotated counterclockwise around the optical axis by the spring 6, and at the same time, the pin 5 and the groove 7a are inserted. Since the second diaphragm lever 7 also rotates in the same direction along with the arm 9, the diaphragm drive plate 2 rotates counterclockwise by a certain amount through the inclined groove 9a and the protrusion 2b to narrow the diaphragm blade 1. Be done. The relationship between the stroke of the first throttle lever 3 and the number of aperture steps at this time follows the reference setting curve of the solid line C shown in FIG.

Next, when a lens group (not shown) is moved to a wide-angle position, the diaphragm blade 1, the diaphragm blade driving plate 2 and the projection 11 slide integrally in the right direction in the figure by a distance L. Therefore, the diaphragm blade drive plate 2 rotates counterclockwise by the sum of the inclination of the inclined groove 9a and the gradient γ of the inclined surface 9b, and the pin 1a of the diaphragm blade moves along the cam groove 2a, As the diameter changes and becomes smaller, the pin 5 is located at the uppermost point of the groove 7a.

As described above, the diaphragm blade drive plate 2 is rotated by the sum of the inclination of the inclined groove 9a and the gradient γ of the inclined surface 9b in accordance with the movement of the lens group, and as a result, the aperture diameter is changed. Thus, the open F value is kept constant regardless of the position of the lens group.

At this position, when the aperture setting lever 4 moves downward in the figure, the pin 5 moves from the uppermost point to the lowermost point of the groove 7a by the initial rotation of the first aperture adjusting lever 3, and then the The diaphragm lever 7 and the arm 9 of No. 2 are displaced to rotate the diaphragm blade drive plate 2 to operate the diaphragm blade 1. Here, assuming that the stroke of the first throttle lever 3 corresponding to the moving distance of the pin 5 in the groove 7a is δ, the relationship between the stroke of the first throttle lever 3 and the number of aperture steps is shown in FIG. As described above, since the first and second aperture stop levers do not participate in the actual aperture stop at the initial stage δ, the result is as shown by the broken line C ′, and the error in one or more aperture stops during wide-angle shooting is eliminated.

By the way, assuming that the above-mentioned stroke δ is not provided at the wide angle, as shown in FIG. 5, when the diaphragm is at the telephoto position, the relationship between the number of diaphragm steps and the stroke of the first diaphragm lever 3 is as shown by the solid line C. Although it follows the standard setting curve, when the diaphragm moves to the wide-angle position due to zooming, the diaphragm blade drive plate 2 rotates with this movement and the pin 1a of the diaphragm blade 1 slides in the cam groove 2a. The relationship between the number of steps and the stroke of the first aperture stop lever 3 is as shown by the chain double-dashed line C ″. When the metering circuit instructs the aperture meter to narrow down the aperture by two steps, the aperture setting lever 4 of the camera body only has a stroke in which the first aperture lever 3 of the lens is a. It stops at the position where the dynamic. Although the telephoto position at this time the lens (TELE) first diaphragm interrupt lever 3 may have an appropriate value refine two stages, caused an erroneous difference △ ₁ in the wide angle position (WIDE) Refine Will be passed.

[0011]

[Problems to be solved by the device]

In the conventional technique as described above, the error with the reference setting curve can be eliminated as shown in FIG. 4 after the first narrowing down, but before the first narrowing down, the same error is represented by Δ ₂ and Δ _{3 in} the figure, for example. As described above, there is a problem that an error occurs.

The present invention has been made in view of such conventional problems. The first narrowing lever 3 is displaced proportionally to the change in the number of stages of the diaphragm in the vicinity of the first stage of the diaphragm, and thereafter. In the same way, without changing the conventional diaphragm control system between the camera body and the interchangeable lens, in which the first diaphragm lever is displaced in a uniform manner, the standard setting curve can be used in any state of zooming or focusing. It is an object of the present invention to provide an interchangeable lens diaphragm device that does not cause an error in.

[0013]

[Means for Solving the Problems]

 In the present invention, the diaphragm blade 1, the first diaphragm lever 3 that interlocks with the diaphragm setting lever 4, the second diaphragm levers 7 and 9 that interlock with the first diaphragm lever 3, and the second diaphragm lever 7 , 9 are interlocked with the diaphragm blade driving member 2, and the diaphragm blade 1 is moved in response to the operation of the diaphragm blade driving member 2 in such a manner that the displacement amounts of the second narrowing levers 7 and 9 are equal to the number of diaphragm steps. The cam means 2a, 1a, 1b which are controlled so as to change and the diaphragm blade drive member 2 which is linearly and rotationally moved in conjunction with the lens moving operation actuates the cam means 2a, 1a, 1b to stop the diaphragm. It is installed between the open F-number correcting means 2b and 9a for correcting the aperture and keeping the open F-number constant, and between the first narrowing lever 3 and the second narrowing levers 7 and 9, and is the first one for the number of diaphragm steps. Displacement amount of the narrowing lever of 2 etc. The displacement amount of the first throttle lever 3 with respect to the number of diaphragm steps is proportionally changed in a region near the first stage of the number of diaphragm steps, and is equally changed in a larger region thereafter, in accordance with the dynamic change. A diaphragm device for an interchangeable lens is constructed which is characterized by having a converting means for controlling and 3b and 13.

[0014]

[Action]

 The displacement amount of the second throttle lever with respect to the number of aperture steps changes in an equal difference. The isomorphous change of the second throttle lever with respect to the number of throttle steps causes the conversion means to change the displacement amount of the first throttle lever with respect to the number of throttle steps in a proportional manner in the region corresponding to the vicinity of the first stage of the throttle, and thereafter. In the area, it is changed equal to.

[0015]

【Example】

 A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of a zoom lens according to an embodiment of the present invention, in which both the aperture diameter and the aperture position change in association with zooming, and FIG. 2 shows the stroke of the aperture lever and the aperture of this embodiment. It is a figure which shows the relationship with the number of steps.

A predetermined number of diaphragm blades 1 are combined, and each of them is provided with a pin 1b fitted in a hole of a fixed ring (not shown) and a pin 1a fitted in a cam groove 2a of the diaphragm blade drive plate 2. There is. The diaphragm blade drive plate 2 is rotatable around the optical axis and has a protrusion 2b on its outer circumference. The shape of the cam groove 2a of the diaphragm blade drive plate 2 is formed so that the number of diaphragm steps changes equidistantly with respect to the stroke of the second diaphragm lever 7, as shown by the solid line D in FIG.

The first stop lever 3 engages with the stop setting lever 4 on the camera side and has a disc portion 3a (a part of which is omitted in FIG. 1). The disc portion 3a is mounted on a fixed lens barrel (not shown). It is rotatably supported around its axis. The first narrowing lever 3 has a cam portion 3b and is urged downward by a spring 6 in the drawing. The second squeezing lever 7 is rotatably provided about a shaft 8, has an arm 9 extending in the optical axis direction at one end, has a pin 13 engageable with the cam portion 3b, and has a spring 12 It is biased downward in the figure, that is, counterclockwise. The pin 13 is always in contact with the cam portion 3b. The arm 9 is formed with an inclined groove 9a that engages with the projection 2b of the diaphragm blade drive plate 2.

Next, the operation will be described. When the aperture value to obtain the proper exposure based on the subject brightness, shutter speed, film sensitivity, etc. is determined by the photometry circuit of the camera during shooting, the aperture is set just before the shutter front curtain run by the amount according to that value. When the lever 4 moves downward in the drawing, the first focusing lever 3 rotates counterclockwise around the optical axis by the spring 6, and at the same time, the second focusing lever 7 moves through the cam portion 3b and the pin 13. Since it also rotates in the same direction with the arm 9, the diaphragm drive plate 2 rotates counterclockwise by a predetermined amount through the inclined groove 9a and the projection 2b, and the diaphragm blade 1 is narrowed down. The relationship between the stroke of the first throttle lever 3 and the number of aperture steps at this time follows the reference setting curve of the solid line C shown in FIG.

Next, when a lens group (not shown) is moved to a wide-angle position, the diaphragm blade 1, the diaphragm blade driving plate 2 and the projection 11 slide integrally in the right direction in the figure by a distance L. Therefore, the diaphragm blade drive plate 2 rotates counterclockwise by the inclination of the inclined groove 9a, the pin 1a of the diaphragm blade moves along the cam groove 2a, and the diaphragm diameter changes and becomes smaller.

Next, conversion to a reference setting curve showing the relationship between the stroke of the first throttle lever 3 and the number of aperture steps will be described. In FIG. 2, line D shows the relationship between the stroke of the second throttle lever 7 and the number of aperture steps. That is, it is shown that the displacement amount of the second throttle lever 7 with respect to the number of throttle stages changes in an equal manner, and the line D is determined by the shape of the cam groove 2a.

A line C is a reference setting curve defined based on the conventional diaphragm control system between the camera body and the interchangeable lens, and shows the relationship between the stroke of the first diaphragm lever 3 and the number of diaphragm steps. .. The shape of the cam portion 3b is such that the stroke of the second throttle lever 7 corresponding to an arbitrary number of throttle steps on the line D in FIG. 2 is changed to the stroke of the first throttle lever 3 corresponding to the same number of throttle steps on the line C. Decide to convert. For example, it is determined that the stroke x'corresponding to one narrowing stage number in the figure is converted to x and the stroke y'corresponding to three narrowing stage numbers is converted to y.

With the above-described configuration, the stroke and aperture of the first aperture lever before the first stage of aperture stop, which has been a problem in the related art, can be achieved without changing the aperture control system between the conventional camera body and the interchangeable lens. The error with respect to the reference setting curve in the relationship of the number of steps can be eliminated regardless of the telephoto position (TELE) or the wide-angle position (WIDE) of the lens. This is because the amount of displacement of the second stop lever 7 changes with respect to the number of stop steps, and the stop blade drive plate 2 is rotated by zooming or focusing so that the pin 1a of the stop blade 1 moves in the cam groove 2a. Even if it slides, an error does not occur in the relationship (line D) between the stroke of the second throttle lever 7 and the number of aperture steps.

The points to be noted in this embodiment are as follows. That is, the difference in displacement of the second throttle lever 7 with respect to the number of throttle steps is adjusted by the cam portion 3b of the first throttle lever 3 to narrow the displacement amount with respect to the number of throttle steps of the first throttle lever 3. It is to be converted into the geometrical change in the area corresponding to the vicinity of the first stage and the geometrical change in the area thereafter.

As described above, in the interchangeable lens such as the zoom lens and the macro lens which keeps the open F-number constant by changing the aperture diameter according to the lens moving operation such as zooming and focusing. In accordance with the operation, the second narrowing lever and the changing means (the cam portion 3b of the narrowing lever 3 and the pin 13 of the narrowing lever 7) which are set so that the displacement amount thereof with respect to the number of the narrowing stages is changed by the cam means in an equal difference manner. ), The displacement amount with respect to the number of diaphragm steps changes proportionally in the region corresponding to the vicinity of the first stage of the diaphragm, and changes in the subsequent regions in an equal difference. A diaphragm device having a first diaphragm lever that engages with a body-side diaphragm setting lever set according to a standard setting curve in the system can be constructed.

[0025]

[Effect of the device]

 Since the displacement amount of the second throttle lever changes with the number of aperture steps evenly, even if the aperture blade drive plate rotates due to zooming or focusing and the aperture blade pin slides in the cam groove, There is no error in the relationship between the stroke of the throttle lever and the number of throttle steps. The change in displacement of the second throttle lever with respect to the number of aperture steps is proportionally changed by the conversion means in the region corresponding to the vicinity of the first stage of aperture with respect to the amount of displacement of the first aperture lever with respect to the number of aperture steps. Since it is possible to change it evenly in subsequent areas, there is no need to change the conventional diaphragm control system between the camera body and the interchangeable lens, and the relationship between the stroke of the diaphragm setting lever 4 on the body side and the number of diaphragm steps is In addition, it is possible to eliminate the error with respect to the reference setting curve in the relationship between the stroke of the first aperture lever and the aperture stage number before the first aperture stage.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the stroke of the aperture lever and the number of aperture stages in the present embodiment.

FIG. 3 is a perspective view of a conventional example.

FIG. 4 is a diagram showing the relationship between the stroke of the aperture lever and the number of aperture stages in the conventional example.

FIG. 5 is a diagram showing the relationship between the stroke of the throttle lever and the number of aperture steps in the present embodiment.

[Explanation of symbols]

1 diaphragm blade 2 diaphragm blade drive plate 2a cam groove 3 first diaphragm lever 3b cam portion 7 second diaphragm lever 9 arm 12 spring 13 pin In the drawings, the same or corresponding parts are designated by the same reference numerals.

Claims (2)

[Scope of utility model registration request] 1. A diaphragm blade, a first diaphragm lever linked to a diaphragm setting lever, a second diaphragm lever linked to the first diaphragm lever, and a diaphragm blade drive linked to the second diaphragm lever. A member, cam means for controlling the diaphragm blades according to the operation of the diaphragm blade driving member so that the displacement amount of the second diaphragm lever with respect to the set number of diaphragm stages changes in an equal difference, and a lens moving operation. When the diaphragm blade driving member that moves linearly and rotationally in conjunction with the above is operated, the cam means is operated to correct the diaphragm opening to maintain the opening F value constant, and the first diaphragm lever. Is installed between the first aperture stop lever and the second aperture stop lever, and the displacement amount of the first aperture stop lever relative to the aperture stage number is linked to the differential change of the displacement amount of the second aperture stop lever with respect to the aperture stage number. In the region near the first stage of several varied geometrically, the iris of the interchangeable lens, characterized by having converting means for controlling as to arithmetically the change in the subsequent larger area. 2. The converting means includes a cam means provided on the first narrowing lever and an engaging portion provided on the second narrowing lever and engageable with the cam means. The diaphragm device for an interchangeable lens according to claim 1.