JP2504327Y2 - Shutter-curtain control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a device for controlling a shutter curtain provided in, for example, a single-lens reflex camera.

[Conventional technology and problems]

Conventionally, for example, in a single-lens reflex camera or the like, there is a single-lens reflex camera provided with a focal plane shutter which is arranged immediately in front of the focal plane and is composed of two curtains, a front curtain and a rear curtain.
Such a shutter is closed when the camera is not in operation, so that when the back cover of the camera is opened, the front curtain is exposed inside the aperture.

[Problems to be solved by the device]

However, when the back cover of the camera is opened for loading a film or the like, the user may accidentally damage the shutter curtain by touching the shutter curtain.

The present invention has been made for the purpose of providing a device capable of reliably preventing damage to the shutter curtain when the back cover of the camera is open.

[Means for solving the problem]

A shutter curtain control device according to the present invention includes means for detecting an open / closed state of a back lid, and a shutter curtain from a first state to a second state when the detecting means detects an open state of the back lid.
When the power supply voltage of the camera is controlled by the curtain control means, the power supply voltage of the camera is controlled so that the shutter curtain is not exposed in the aperture of the camera body. When it is detected that it is less than a predetermined value, the shutter curtain is returned to the first state,
It is characterized in that the shutter curtain is returned to the inside of the aperture when a predetermined time or more has elapsed after the shutter curtain has run while the case back is open.

〔Example〕

 The present invention will be described below with reference to the illustrated embodiments.

FIG. 1 (a) shows the back cover open state in a conventional camera, and FIG. 1 (b) shows the back cover open state in a camera to which an embodiment of the present invention is applied. These figures show a camera with a so-called vertical running focal plane shutter.
Is shown. That is, the shutter curtain has a front curtain 12 and a rear curtain (not shown), and travels in the vertical direction of the camera body to perform exposure. In this type of camera, the front curtain 12 is conventionally exposed in the aperture when the back cover 13 is opened (FIG. 1 (a)).
It is configured so that 12 is not exposed in the aperture 14 (FIG. 1 (b)).

FIG. 2 is a block diagram of a control circuit which is provided in the camera 11 and performs various information processing for photographing. Microcomputer (CPU) 20 is connected to the power supply i.e. battery V _B through a terminal V _DD. A release magnet 21, a front curtain magnet 22, and a rear curtain magnet 23 are connected to the CPU 20, and the CPU 20 performs release control and shutter control. The release magnet 21 is for controlling the vertical movement of the mirror and the like, and the front curtain magnet 22 and the rear curtain magnet 23 attract the front curtain and the rear curtain, respectively, and hold them in a charged state.

Further, a film winding completion detection switch 24 and a film feed detection switch 25 are connected to the CPU 20, and the film winding state is detected. Further, a main switch 26 and a back cover switch 27 are connected to the CPU 20, the main switch 26 is for turning on the power to the CPU 20, and the back cover switch 27 is turned on when the back cover 13 is opened. It is a switch that becomes a state. Various information is input to the CPU 20 by various switches. CPU20 for various information
Is displayed by the display panel 28 connected to.

FIG. 3 shows a flow chart of the shutter curtain control program in this embodiment.

First, in step 101, it is determined whether or not the main switch 26 is on. If the main switch 26 is in the ON state, steps 102 and thereafter are executed, and if it is in the OFF state, steps 111 and thereafter are executed.

If the main switch 26 is on, first step 10
At 2 the flag is cleared. This flag is set in step 119 described later. Next, at step 103, it is determined whether or not the back cover 13 is opened by checking the on / off state of the back cover switch 27. When the back cover 13 is closed, it is in a normal state, and the routine proceeds to step 122, where normal camera operation is performed. On the other hand, when the back cover 13 is opened,
In step 104, the battery voltage is checked. That is, the measured battery voltage V is greater or whether it is determined than the shutter charge operation can limit voltage V _e. This limit voltage V _e is a set value stored in advance in the memory of the CPU 20. When the actual battery voltage V is less than the limit voltage V _e, it becomes impossible shutter charge operation in step 108 to be described later, step 122
Then, the normal camera operation is performed.

Back cover 13 is opened, and when the battery voltage V is higher than the limit voltage V _e, the shutter front curtain 12 is made to travel at step 105, the camera body aperture
It is controlled so as not to be exposed in the inside 14 (see FIG. 1 (b)). Then, in step 106, the battery voltage V is checked again. In step 106 if the battery voltage V is determined to be less than the limit voltage V _e, because more battery voltage may become impossible shutter charging the drops, the flow proceeds to step 109, immediately the shutter is charged The shutter is restored to its original state where it can be moved back into the original aperture. Then, in step 122, normal camera operation is performed.

On the other hand, when it is determined in step 106 that the battery voltage V is higher than the limit voltage V _e , step 107
At, by checking the on / off state of the back cover switch 27, it is determined whether or not the back cover 13 is opened. As long as the back cover 13 is open, steps 106 and 107 are repeatedly executed, and when the back cover 13 is closed, step 10 is performed.
At 8, the shutter is charged and the original aperture is restored. That is, after the trailing curtain has been driven, the leading curtain and the trailing curtain are charged, and the shutter returns to the original runnable state. Then in step 121,
The film is loaded and the camera is ready for shooting. Then, the process proceeds to step 122, and normal camera operation is performed.

On the other hand, when it is determined in step 101 that the main switch 26 is in the off state, first in step 111, it is determined whether or not the flag has already been set.
This flag is set in step 119, so when this step 111 is executed for the first time,
Flag not set. Therefore, normally, the routine proceeds to step 112, where it is determined whether the case back 13 is opened. If the back cover 13 is closed, the process returns to step 101. If the back cover 13 is opened, at step 113, it is checked whether the battery voltage V is higher than the limit voltage V _e . When the battery voltage V is equal to or lower than the limit voltage V _e , shutter charging cannot be performed in step 120, which will be described later, so the process returns to step 101.

Back cover 13 is opened, and when the battery voltage V is higher than the limit voltage V _e, in step 114, similarly the shutter front curtain 12 is made to travel to step 105, not exposed in the aperture 14 of the camera body Controlled as. In step 115 is checked battery voltage V is the battery voltage V is higher than the limit voltage V _e, in step 116, whether a predetermined time has elapsed from the travel of the front curtain in step 114 is determined. When it is determined in step 116 that the fixed time has not yet elapsed, it is determined in step 117 whether the case back is opened. As long as the case back 13 is open, step
When the back cover 13 is closed by repeating steps 115, 116, and 117, the shutter is charged in step 120 and the original aperture is restored. Then, the process returns to step 101.

On the other hand, if the battery voltage V is determined to be below the limit voltage V _e at step 115, because more battery voltage may become impossible shutter charging the drops, the flow proceeds to step 118, immediately shutter charge Then, after returning to the original aperture, the process returns to step 101.

If it is determined in step 116 that the fixed time has elapsed, the flag is set in step 119. Then, in step 120, the shutter is charged and returned to the inside of the aperture, and then the process returns to step 101. In this way, the main switch is forced to perform shutter charge after a certain period of time.
This is to prevent battery consumption when the case back is left open in F state.

After that, when proceeding from step 101 to step 111, since the flag has already been set in step 119,
The process returns from step 111 to step 101 again. That is, steps 101 and 111 are repeatedly executed, and steps 112 and thereafter are not executed.

As described above, the present embodiment is configured so that the shutter front curtain 12 is made to run and is not exposed to the aperture of the camera when the back cover 13 is opened for loading a film or the like. Therefore, when the back cover is opened, there is no risk of the user touching the shutter curtain, and damage to the shutter curtain is reliably prevented.

Further, the opening of the back cover 13 is detected, in a state in which the shutter curtain is retracted (the second state), if the battery voltage V is less than the critical voltage V _e, the shutter curtain in the aperture performed immediately shutter charge operation It has been restored (first state). Therefore, make sure that the second shutter curtain
You can return to the first bear from this state.

Even before the front curtain runs, the battery voltage V
Is less than or equal to the limit voltage V _e , the shutter curtain is configured not to operate in the second state, and it is possible to prevent from being unable to return from the second state to the first state.

When the main switch 26 is off and the case back 13 is open, the shutter curtain is forced to the first position after a certain period of time.
Since the state is returned to, the battery will not be uselessly consumed by being left in the second state for a certain time or more.

The above embodiment is an example in which the present invention is applied to a camera having a vertically running focal plane shutter.
The present invention is not limited to such a focal plane shutter, but can be applied to a laterally running focal plane shutter.

[Effect of device]

As described above, according to the present invention, the shutter curtain can be reliably prevented from being damaged when the back cover of the camera is opened, and the shutter curtain is retracted from the original state (second state). It is possible to reliably return to the state (1st state).

[Brief description of drawings]

FIG. 1 (a) is a perspective view showing a conventional camera with a back cover opened, and FIG. 1 (b) is a perspective view showing an embodiment of the present invention with the back cover opened, FIG. Is a diagram showing a control circuit of the camera, and FIG. 3 is a flowchart of a shutter curtain control program. 12 …… First curtain 13 …… Back cover 14 …… Aperture

Claims (3)

(57) [Scope of utility model registration request] 1. A means for detecting the open / closed state of the back lid, and when the detection means detects the open state of the back lid, the shutter curtain is operated from the first state to the second state, and the camera body is operated. A shutter control means for controlling the shutter curtain so as not to be exposed, and a voltage detection means for detecting the power supply voltage of the camera. The curtain control means is such that the power supply voltage of the camera is equal to or less than a predetermined value. Is detected, the shutter curtain is returned to the first state, and when the shutter curtain has run for a predetermined time or more with the back cover being opened, the shutter curtain is returned to the aperture. A shutter curtain control device characterized by: 2. The shutter curtain control device according to claim 1, wherein the curtain control means returns the shutter curtain to the inside of the aperture when the back cover is closed. 3. The curtain control means, when the shutter curtain is in the first state, and when the power supply voltage is equal to or lower than a predetermined value, even if the opening of the back lid is detected, the shutter curtain is closed. The shutter curtain control device according to claim 1, wherein the shutter curtain control device is not operated in the second state.