JPH0446470A - Still camera - Google Patents

Abstract

PURPOSE:To control easily by providing a first iris member and a second iris member for respectively varying an image pickup element and the opening area of an optical path to the image pickup element. CONSTITUTION:When a shutter switch is turned on and a still photographic mode is selected, the opening area of a first iris member 4 is controlled at a value corresponding to a set iris value, and the opening area of a second iris member 5 is controlled at zero. Just after the opening area of the second iris member 5 becomes zero, the second iris member 5 is again displaced to a side opened to its full width and simultaneously an image pickup element 2 is turned to a photoelectric conversion state. And after the lapse of the time corresponding to a shutter speed set from a starting point of the opening of the second iris member 5, the opening area of the first iris member 4 is controlled at zero. Then, the still surface of exposure corresponding to a trapezoidal area with oblique lines is obtained, and after a still photographing is finished, an automatic iris state again returned.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a still camera that takes still images using an image sensor, and relates to a shutter technology thereof.

[Summary of the Invention] The present invention includes an image sensor and a first aperture member and a second aperture member that respectively vary the aperture area of an optical path to the image sensor, and when a still photography mode is selected, the 1st
controlling the aperture area of the aperture member to a set value and controlling the aperture area of the second aperture member to zero, and controlling the aperture area of the second aperture member to zero;
controlling the aperture area of the aperture member to be larger than the aperture area of the first aperture member, and one of the first aperture member and the second aperture member after a period of time corresponding to the set shutter speed has elapsed; By controlling the aperture area to zero, there are only two mechanically controlled objects, the first diaphragm member and the second diaphragm member, in the still photography mode, and control becomes easy.

[Prior Art] Still cameras are known that have an image sensor and magnetically record still image information captured by the image sensor on, for example, a disk. Conventional examples of this type of still camera are shown in FIGS. 3 to 5.

In FIG. 3, an optical path is configured in the camera body 1 to take in light from a subject, and an image sensor 2 is located at the innermost part of this optical path.
is provided. This image sensor 2 is controlled by a drive signal from a control circuit 3, and the output video signal of the image sensor 2 is guided to the control circuit 3 and sent to a monitor in the viewfinder and a recording head via a signal processing circuit (not shown). being guided. In the optical path, a focus lens group, a zoom lens group, etc. (not shown) are arranged, as well as an aperture member 10 and a focal plane shutter 11. The diaphragm member 10 has a plurality of vanes to vary the aperture area of the optical path. The aperture member 10 is driven by an actuator 6, and this actuator 6 is driven by a control circuit 3.
It is controlled by the control signal. A position detection sensor 8 is attached to this actuator 6, and this position detection sensor 8 detects the opening position of the aperture member 10. The output of this position detection sensor 8 is led to the control circuit 3.

As shown in detail in FIG. 4, the focal plane shutter 11 has a front curtain 12 and a rear curtain 13.
13 are respectively displaced between a fully closed position and a fully open position of the optical path. The front curtain 12 is urged toward the open position by the spring force of a spring 14, and the rear curtain 13 is urged toward the fully closed position by the spring force of a spring 15. The front curtain 12 and the rear curtain 13 are driven independently by actuators, and the actuator 7 is controlled by a control signal from a control circuit 3.

The control circuit 3 receives the output of the image sensor 2 and the output of the position detection sensor 8 as described above, and also receives the aperture value, shutter speed value, shutter switch ON information, power supply ON information, etc. A control signal is output to each actuator 6, 7, etc. according to the input state.

In the above configuration, when the power is turned on as shown in FIG. 5, the front curtain 12 and rear curtain 13 of the focal plane shutter 11 are respectively positioned at the fully open position, and the output of the image sensor 2 is supplied to the viewfinder monitor. and is also guided to the control circuit 3. The control circuit 3 controls the aperture area of the aperture member 10 so that the average level of the video signal is approximately constant;
The aperture member 10 enters the auto-iris state. Here, when the shutter switch is turned on and the still photography mode is selected, the aperture area of the aperture member 10 is set to a value corresponding to the set aperture value, and the focal plane shutter 1
The front curtain member 2 of No. 1 is moved to the fully closed position. Immediately after setting the front curtain 12 of the focal plane shutter 11 to the fully closed position against the spring force, the front curtain 12 is released and displaced to the fully open position side.

After a time period (T) corresponding to the set shutter speed has elapsed from the time when the front curtain 12 was released, the rear curtain 13 of the focal plane shutter 11 is released and moved to the fully closed position side. Then, the image sensor 2 is irradiated with light of an exposure amount corresponding to the trapezoidal area indicated by hatching in FIG. 5, and the output video signal of the image sensor 2 based on this exposure amount is recorded on, for example, a disk.

[Problems to be Solved by the Invention] However, in the still photography mode, three points, the aperture member 10, the front curtain 12 of the focal plane shutter 11, and the rear curtain 13 of the focal plane shutter 11, must be mechanically controlled. However, the disadvantage is that the control is complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a still camera that is easy to control by reducing the number of mechanical objects to be controlled during still photography mode.

[Means for Solving the Problems] A still camera of the present invention for achieving the above-mentioned problems includes: an image sensor that converts optical information entering through an optical path in the camera body into an electrical signal; and an aperture in the optical path. A still camera having a first diaphragm member whose area is variable, and a second diaphragm member which varies the aperture area of the optical path; The aperture area of the second aperture member is controlled to a set value and the aperture area of the second aperture member is controlled to zero, and immediately after the aperture area of the second aperture member becomes zero, the aperture area of the second aperture member is reduced to the aperture area of the second aperture member. The aperture area of the first aperture member is controlled to be larger than the aperture area of the first aperture member, and the image sensor is brought into a photoelectric conversion state. and a control section that controls the aperture area of one of the aperture members and the second aperture member to be zero.

[Function] When the still shooting mode is selected, the aperture area of the first aperture member is set to the set value, the aperture area of the second aperture member is set to zero, and immediately after this, the aperture area of the second aperture member is set to the set value. At the same time, the image sensor is brought into a photoelectric conversion state, and the aperture area of the first aperture member or the second aperture member is reduced to zero after a period of time corresponding to the set shutter speed has elapsed from the start of aperture of the second aperture member. By doing this, it is possible to take a still image with a predetermined exposure amount, and in the still photography mode, it is only necessary to control the first aperture member and the second aperture member.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

An embodiment of the present invention is shown in FIGS. 1 and 2. FIG.

In FIG. 1, an optical path is configured in the camera body 1 to take in light from a subject, and an image sensor 2 is located at the innermost part of this optical path.
is provided. The image sensor 2 is controlled by a drive signal from a control circuit 3, and the output video signal of the image sensor 2 is guided to the control circuit 3 and also to a monitor in the viewfinder and a recording head via a signal processing circuit (not shown). It's dark. A focus lens group, a zoom lens group, etc. (not shown) are arranged in the optical path, and a first diaphragm member 4 and a second diaphragm member 5 having the same configuration are arranged adjacent to each other. Each diaphragm member 4.degree.5 has a plurality of vanes, and is provided so that the opening area of the optical path can be varied by varying the area of the hole formed by the plurality of vanes. Further, each of the aperture members 4 and 5 is driven by each actuator 6.7.
is controlled by a control signal from the control circuit 3. Control circuit 3 is easy to control since it controls the same diaphragm member 4.5.

Further, a position detection sensor 8 is attached to the actuator 6 of the first diaphragm member 4, and this position detection sensor 8 detects the opening position of the diaphragm member 4 from the drive position of the actuator 6. The output of this position detection sensor 8 is guided to a control circuit 3, and the control circuit 3 performs feedback control of the first aperture member 4 based on the output of the position detection sensor 8. Control circuit 3
Aperture value, shutter speed value, shutter switch ON information, power ON information, etc. are input to , and each actuator 6° 7 and image sensor 2 are activated according to each input state.
control etc.

In the above configuration, as shown in FIG. 2, when the power is turned on, the second diaphragm member 5 is positioned at the fully open position r, and the first diaphragm member 4 is adjusted to the average level of the output video signal of the image sensor 2. The aperture area is controlled so as to keep it approximately constant. That is,
An auto iris state is entered, and an image of approximately the same brightness is displayed on the viewfinder monitor. Here, when the shutter switch is turned on and still shooting mode is selected,
The aperture area of the first aperture member 4 is controlled to a value corresponding to the set aperture value, and the aperture area of the second aperture member 5 is controlled to be zero. Immediately after the aperture area of the second diaphragm member 5 becomes zero, the second diaphragm member 5 is again displaced to the fully open position, and at the same time, the image sensor 2 is brought into the photoelectric conversion state. Then, after a time period (T) corresponding to the set shutter speed has elapsed from the start of opening of the second diaphragm member 5, the aperture area of the first diaphragm member 4 is controlled to zero. As a result, a still image with an exposure amount corresponding to the area of the trapezoid surrounded by diagonal lines in FIG. 2 can be obtained, and when still photography is finished, the auto iris state is returned again.

In this embodiment, the first diaphragm member 4 is moved to the fully closed position after the time (T) corresponding to the shutter speed has elapsed, but the second diaphragm member 5 is moved to the fully closed position. It may be configured to do so. Further, in this embodiment, the opening area of the second diaphragm member 5 is controlled to be at the fully open position after being reduced to zero, but it is sufficient to control the opening area to be expanded to the opening area of the first diaphragm member 4 or more.

[Effects of the Invention] As described above, the present invention includes an image sensor and a first diaphragm member and a second diaphragm member that respectively vary the aperture area of the optical path to the image sensor, and is capable of shooting in still photography mode. is selected, the aperture area of the first aperture member is controlled to the set value, and the aperture area of the second aperture member is controlled to zero, and the aperture area of the second aperture member is controlled to the set value. The aperture area of one of the first aperture member and the second aperture member is controlled to be expanded to be larger than the aperture area of the first aperture member, and the aperture area of one of the first aperture member and the second aperture member is reduced to zero after a time corresponding to the set shutter speed has elapsed. Because of this control, there are only two mechanically controlled objects, the first diaphragm member and the second diaphragm member, in the still photographing mode, and the control becomes easy.

In addition, in the past, when the still shooting mode was selected, the front curtain of the focal plane shutter was moved to the fully closed position against spring force, so it took a relatively long time to start shooting.
However, according to the present invention, since the shutter is replaced by an aperture member that can open and close at high speed, the time (1) until the start of shooting is shortened, and the shutter can be opened and closed at high speed. can be cut.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of a still camera, FIG. 2 is a time chart, and FIGS. 3 to 5 show a conventional example. , FIG. 3 is a schematic diagram of a still camera, FIG. 4 is a schematic diagram of a focal plane shutter, and FIG. 5 is a time chart. DESCRIPTION OF SYMBOLS 1...Camera main body, 2...Imaging element, 3...Control circuit, 4...1st aperture member, 5...2nd aperture member.

Claims (1)

[Claims] (1) A still camera including an image sensor that converts optical information entering through an optical path in the camera body into an electrical signal, and a first aperture member that changes an aperture area of the optical path, the aperture of the optical path a second aperture member whose area is variable; and when a still photography mode is selected, the aperture area of the first aperture member is controlled to a set value and the aperture area of the second aperture member is set to zero; control so that the aperture area of the second aperture member becomes greater than the aperture area of the first aperture member immediately after the aperture area of the second aperture member becomes zero, and the image sensor is in a conversion state, and after a time period corresponding to a set shutter speed has elapsed from the start of opening of the second diaphragm member, the aperture area of one of the first diaphragm member and the second diaphragm member is set to zero. A still camera characterized by comprising a control section for controlling the still camera.