JPH01310333A - Stroboscopic photographing device - Google Patents

Abstract

PURPOSE:To prevent energy waste by controlling the main capacitor voltage of a stroboscope to be at the level between the voltage level which is not less than the emittable voltage and the voltage level which is higher than such emittable voltage level when the condition does not allow photographing and changing the capacitor until it exceeds over the above higher voltage level when the condition allows the photographing. CONSTITUTION:At the point when the oscillation of a DC-DC converter is continued, the charging voltage of the main capacitor 8 is increased, and input voltage to the non-inversion input end is over the reference voltage Vr1 to a inversion input end, the output of a comparater 12 becomes at high level, a transistor 21 is turned on, and a LED 20 is lighted. When the condition does not allow photographing, the oscillation and the stop of a converter 3 are repeated between the voltage level which does not permit the charging voltage of the capacitor 8 of the stroboscope 20 to be less than the emissive voltage and the voltage level of the non-inversion input end of the comparator which is higher than the above voltage level. When the condition allows photographing, a TR 6 is not turned on when a switch circuit 35 is turned off and the output of a comparator 13 is at the high level, and the oscillation of the converter 3 is continued.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a strobe photography device, and particularly to strobe charging control.

(Background of the Invention) Conventionally, various proposals have been made for improving the charging circuit of a camera with a built-in strobe to prevent the energy of the power source battery from being wasted. For example, JP-A-61
In No. 132937, the operation of the regulator is made different depending on whether the camera is in a shooting-enabled state or not, to prevent energy wastage.

However, in the energy-saving methods that have been proposed, including the above-mentioned conventional example, it is impossible to take pictures if the cartridge is not loaded in the cartridge chamber of the camera or if a lens is not attached to the camera. Even in a non-shooting state, the built-in strobe is charged to a fully charged state without any restrictions on its charging operation, and if you take a blank shot in that state, the built-in strobe will fire while fully charged. Especially in the case of a built-in strobe with a full flash mode or a parallel flash control mode, the flash will be emitted completely in vain.

The above-mentioned aerial photography is often done to check whether the camera is working properly before loading film, and especially at camera stores, aerial photography is often used when explaining the camera's functions to customers. This had to be done many times, and it was not possible to limit the wasteful use of energy.

(Object of the Invention) An object of the present invention is to provide a strobe photographing device that can prevent wasteful energy consumption by a strobe.

(Features of the Invention) In order to achieve the above object, the present invention provides a first level in which the voltage of the main capacitor of the strobe does not fall below the flash-enabled voltage when the detection means detects a state in which photography is not possible. and a second level that is higher than the first level, and if a shooting ready state is detected, the strobe is charged to a voltage that exceeds the second level. A charge control means is provided, and when the detection means detects a state in which photographing is not possible, charging of the main capacitor of the strobe is prohibited, and when a state in which photographing is possible is detected, charging of the main capacitor is prohibited. The present invention is characterized in that it is equipped with a charging control means for performing the above operation, and thereby reduces the amount of strobe light emitted during sky photography, which may be performed when photography is not possible, and also prohibits strobe light emission itself. .

(Embodiments of the Invention) Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 shows an example of the structure of a built-in strobe according to the present invention.
is the battery which is the power source, 2 is the switch that controls the power supply to the load, and 3 is the oscillation transistor, which controls the primary current of the oscillation transformer 4 and generates a high voltage in the secondary winding of the oscillation transformer 4. , 5, and 6 are transistors that control the oscillation transistor 3. The emitter and collector of the transistor 5 are connected between the emitter and collector of the oscillation transistor 3, and the collector and emitter of the transistor 6 are connected between the base of the transistor 5 and the ground line. connected to enter. 7 is a resistor, 8 is a main capacitor, 9 is a diode for charging the main capacitor 8 to high DC voltage, 1
0 is a Zener diode, and 11 is a resistor that limits the current flowing through the Zener diode 10. Also 12.13
is a comparator, 14, 15.16 are resistors for inputting the reference voltage to the inverting input terminal of the comparator 12.13, and 17, 18.19 are the comparators 12, 13.
A voltage dividing resistor 20 inputs a voltage proportional to the charging voltage of the main capacitor 8 to the non-inverting input terminal of the comparator 12.
It is a light emitting diode that lights up when the output of the main capacitor 8 becomes high level and the transistor 21 is turned on, indicating that the charging voltage of the main capacitor 8 has reached the voltage that allows light emission. A transistor 22 turns on when the transistor 21 turns on, and enables supply of gate current to the thyristor 23.

24 is a synchro terminal connected to a synchro contact (not shown) on the camera side, and when the synchro contact is short-circuited by a release signal, a gate current flows to the thyristor 23;
5 is a trigger capacitor, 26 is a trigger coil, and 27 is a resistor that limits the charging current of the trigger capacitor 24.

2B, 29, 30, and 31 are resistors, and 32 is a flash discharge tube, which is connected in parallel with the main capacitor 8. A transistor 33 short-circuits the resistor 16 when turned on. 34
35 is an input terminal that receives a photographing state signal or a non-photographing state signal from an electronic circuit in the camera body (not shown); 35 is turned off when a photographing enable state signal is input through the input terminal 34, and the non-photographing state signal is turned off. This is a switch circuit that is turned on by input.

Next, the operation will be explained. When the switch 2 is turned on, current flows from the power supply battery 1 to the primary sides of the oscillation transistor 3 and the oscillation transformer 4, and the DC-DC converter starts oscillating. As a result, a current rectified by the diode 9 flows from the secondary side of the oscillation transformer 4 to the main capacitor 8, charging it to a high DC voltage. At the inverting input terminal of the comparator 12, there is a Zener diode 10 and a resistor 14, 15°1.
The reference voltage Vr1 (see FIG. 2) set by 6 is input. Further, a voltage proportional to the charging voltage of the main capacitor 8 is input to the non-inverting input terminal of the comparator 12 . Therefore, the oscillation of the DC-DC converter continues and the charging voltage of the main capacitor 8 increases, causing the comparator 12
When the input voltage to the non-inverting input terminal of the inverting input terminal exceeds the reference voltage Vr1 to the inverting input terminal, the output of the comparator 12 becomes high level, the transistor 21 is turned on, and the light emitting diode 20 lights up. The resistors 14, 15, and 16 adjust the reference voltage Vr1 to the inverting input terminal of the comparator 12 so that the charging voltage of the main capacitor 8 at this point matches the light-emitting voltage.

Therefore, the lighting of the light emitting diode 20 indicates that the charging voltage of the main capacitor 8 has reached the voltage that allows light emission. Note that when the light emitting diode 20 is turned on, the transistor 22 is turned on, and the flash discharge tube 32 is ready to emit light.

The inverting input terminal of the comparator 13 is connected to the comparator 12.
A reference voltage equal to the reference voltage to the inverting input terminal of is input. Further, a voltage that is proportional to the charging voltage of the main capacitor 8 and lower than the input to the non-inverting input terminal of the comparator 12 is input to the non-inverting input terminal of the comparator 13, similar to the non-inverting input terminal of the comparator 12. There is. Therefore, the output of the comparator 13 continues to be at the low level for a while even after the output of the comparator 12 becomes high level.
When the charging voltage of the main capacitor 8 further increases and the input voltage to the non-inverting input terminal of the comparator 13 exceeds the reference voltage to the inverting input terminal, it changes to a high level. At this time, if the switch circuit 35 is on, the transistor 6
is turned on, and as transistor 6 is turned on, transistor 5 is also turned on. Therefore, the emitter of transistor 3
The bases are shorted, transistor 3 is turned off, and the DC
-The oscillation of the DC converter is stopped.6 At this time, the transistor 33 is also turned on at the same time to short-circuit the resistor 16.

Therefore, the reference voltage input to the inverting input terminals of the comparators 12 and 13 decreases to Vr2 (see FIG. 2).

Since the charging of the main capacitor 8 is stopped due to the stop of oscillation of the DC-DC converter, the charging voltage of the main capacitor 8 decreases due to leakage etc. as time passes. The input voltage will also gradually drop. At this time, voltage dividing resistors 17, 18.1
9, the input voltage to the non-inverting input terminal of the comparator 13 is lower than the input voltage to the non-inverting input terminal of the comparator 12, so the input voltage to the non-inverting input terminal of the comparator 13 is lower. first becomes lower than the reference voltage Vr2 to the inverting input terminal, which has decreased due to the short circuit of the resistor 16,
Comparator 13 turns its output low. Therefore, the transistor 6 is turned off again, the oscillation of the DC-DC converter is restarted, and the charging voltage of the main capacitor 8 increases.

Therefore, when the charging voltage of the main capacitor 8 becomes equal to the voltage that enables light emission, the voltage value input to the non-inverting input terminal of the comparator 13 is the voltage value V after the reference voltage has decreased.
If the values of the resistors 14 to 16 are set so that the reference voltage is reduced to a value equal to or slightly larger than r2, that is, such a reduction in the reference voltage occurs, then - once DC - When the oscillation of the DC converter stops and the charging voltage of the main capacitor 8 gradually drops due to leakage etc., and reaches a voltage that is substantially equal to the voltage that enables light emission, that is, a voltage that is equal to or slightly larger, the DC-DC converter oscillation restarts, and the charging voltage of the main capacitor 8 rises again.Hereafter, in the non-photographing state, the above-mentioned DC-DC
The converter continues to stop and restart oscillation. Also,
In the photographing state, the switch circuit 35 is in the off state, so even if the output of the comparator 13 becomes high level, the transistor 6 does not turn on, and the oscillation of the DC-DC converter continues.

FIG. 2 shows the change in the charging voltage V of the main capacitor 8 as time T passes. ■R is the charging voltage of the main capacitor 8 when the oscillation of the DC-DC converter is stopped, VL
is the voltage that allows light emission, Vrl and Vr2 are comparator 1
This is the reference voltage input to the inverting input terminals of Nos. 2 and 13. Note that vL is the main capacitor 8 when the light emitting diode 22 is lit.
It is also the charging voltage. In the case of this figure, the oscillation of the DC-DC converter starts and time 1. It becomes possible to emit light and the light emitting diode 20 lights up. After that, the oscillation of the DC-DC converter continues, but at time t2, the oscillation of the DC-DC converter stops and the charging voltage of the main capacitor 8 decreases. Then, at time t3, when the charging voltage of the main capacitor 8 drops to a voltage substantially equal to the light-emitting voltage vL, the oscillation of the DC-DC converter restarts.

Similarly, stopping and restarting the oscillation of the DC-DC converter is repeated thereafter.

In the non-photographing state where the switch circuit 35 is in the on state, after the charging voltage of the main capacitor 8 reaches the voltage that allows light emission as described above, the charging voltage of the main capacitor 8 does not fall below the voltage that allows light emission. By providing a period during which the oscillation of the DC-DC converter is stopped, the amount of strobe light emission during aerial photography can be suppressed, and power consumption can be saved.

After time t4, the switch circuit 35 is in the off state, that is, in the photographing state, and the DC-DC converter continues to oscillate even if the charging voltage vR is exceeded.

Next, a means for detecting whether the camera is in a photographing state or a non-photographing state will be explained with reference to FIG. FIG. 3 shows a longitudinal section of the cartridge chamber, where 101 is the camera body and 102 is the cartridge. Reference numeral 103 denotes a rewind shaft provided at the upper part of the camera body 101, and a fork 103a that engages with the spool of the cartridge 102 and a gear portion 103b that meshes with a rewind gear train (not shown) are integrally provided. Reference numeral 105 denotes a cartridge detection member that penetrates the side wall 101a of the cartridge chamber and is supported so as to be slidable in the left-right direction in the figure.
The movable section of the unwinding shaft 103 is pressed in a direction substantially toward the axis of the unwinding shaft 103, and its tip protrudes into the cartridge chamber.When the cartridge 102 is loaded, it is pushed by its outer periphery and retreated from the cartridge chamber, and its left end portion protrudes into the cartridge chamber. Switch 106 is closed.

The switch 106 is connected to an electronic circuit (not shown) in the camera body, and the electronic circuit sends a signal indicating the state of the switch 106, that is, a photographing state signal or a non-photographing state signal, to the input terminal 34 in FIG. Output.

In this way, by detecting the presence or absence of the cartridge 102 and outputting a status signal indicating whether it is in the photographing state or in the non-photographing state, it is possible to control the amount of flash light emission.

Figures 4 and 5 show other means for detecting whether the camera is in the shooting or non-shooting state, and are front views of the camera body side mount seen from the front; FIG. 5 is a diagram showing the state when the lens side mount is being mounted and the lens mounting detection device is about to start operating, and FIG. 5 is a diagram showing the state when the lens mounting is completed.

In FIGS. 4 and 5, 111 is a camera body side mount, 112 is a lens side mount that is detachably fitted to the camera body side mount 111, 117 is an abutment surface of the camera body side mount 111, and 116 is a matching surface of the camera body side mount 111. Abutment surface 11
One of the three mount claws protruding from the inner circumferential side of 7, 12
1 is one of the mount claws on the lens side that engages with one of the mount claws, and 118 is a mirror box provided within the camera body.

On the back side of the abutment surface 117 of the camera body side mount 111, a lens attachment/detachment responsive member 131, which forms a part of the lens attachment detection device 130, is provided. The lens attachment/detachment response member 131 is a member that is moved by the rotational movement of the lens side mount 112 when attaching the lens to the camera body side mount 111 and when removing the lens from the mount 111, and in this embodiment, two arm portions 131a. and 131b. This lens attachment/detachment responsive member 131 has two arm portions 131a and arm portion 1.
Camera body side mount 111 at the base of 31b
The tip of one arm 131a protrudes to the end position of the rotation area of the mount claw 121 of the lens side mount 1l2, and the arm The tip of the portion 131a is adapted to engage with the mount claw 121. That is, the tip of the arm portion 131a is positioned so as to engage with the lens-side mount pawl 121 at the final stage of the rotational movement of the lens-side mount 112 during lens mounting.

Further, the tips of each of the arm portions 131a and 131b are connected to the fourth
In the figure, they are bent in opposite directions perpendicular to the plane of the paper, and the tip of the other arm 131b is one switch piece 132a of the electrical switch device 132 provided on the back side of the camera body side mount 111. is engaged in. The switch device 132 is the lens attachment/detachment response member 13
1 constitutes a lens attachment detection device 130,
Two switch pieces 132a and 1 with large elastic repulsive force
32b. Since these switch pieces 132a and 132b are provided parallel to each other, they are separated from each other and remain in the off state as shown in FIG. 4 unless pressed by an external force.
When the switch piece 132a is pushed by the arm portion 131b as shown in FIG. 5, the switch piece 132a and the bent portion 132b of the other switch piece 132b come into contact and turn on. The switch device 132 is connected to an electronic circuit in the camera body, and when the switch device 132 is turned on, the first
A photographing state signal is output to the input terminal 34 shown in the figure, and the first
The switch circuit 35 in the figure is turned off.

In this manner, it is possible to control the amount of flash light emitted by detecting the attachment/detaching state of the lens and outputting a status signal indicating whether the camera is in the photographing state or in the non-photographing state.

In the above embodiment, the charge level of the built-in strobe is made different in the non-photographing state to prevent wasteful energy consumption, but by detecting the non-photographing state, the strobe is not charged at all. It is also possible to do this, and an example of a circuit configuration for realizing this is shown in FIG.

In this embodiment, if a non-photographing state signal is input to the input terminal 34, the transistor 6 is turned off and the charging loop is cut off. As a result, as in the case of the embodiment shown in FIG. 1, it is possible to actually emit strobe light (although the amount of light emitted is small), so it does not have the advantage of being able to provide more realistic explanations to users at stores etc. , wasteful consumption of energy can be largely eliminated.

According to this embodiment, the presence or absence of a cartridge in the camera's cartridge chamber is detected, or the state of attachment and detachment of a lens to the camera is detected, and the camera is in a shooting state (capable of shooting) or in a non-shooting state (capable of shooting). (impossible state),
The built-in strobe has a different charging level or is configured to prohibit strobe charging when not shooting.
It is possible to prevent wasteful consumption of energy due to strobe light emission. In particular, it is expected that even greater effects can be obtained by applying Honjitsu to a type of built-in strobe that fires at full capacity or a type that uses parallel flash control.

(Correspondence between the invention and the embodiments) In this embodiment, the cartridge detection member 105, the switch 106, and the lens attachment detection device 130 are the detection means of the present invention, and in the embodiment of FIG. 14-19, transistor 3
3. The switch circuit 35 serves as the charging control means, and in the embodiment of FIG. 6, the transistor 6, the comparator 12, and the resistor 1
4.15.17, 18 and the switch circuit 35 respectively correspond to charging control means.

(Modification) In order to determine whether the photographing state is in the photographing state or the non-photographing state, the means shown in the embodiments in FIGS. 3 to 5 are used. It is also possible to use a signal indicating whether or not the device is loaded. Furthermore, it is possible to make the determination by using the count contents signal of the film counter that responds to film feeding, and furthermore, the open/close status signal of the back cover, and it is also possible to make the determination by combining these. be.

(Effects of the Invention) As described above, according to the present invention, when the detection means detects that the photographing is not possible, the voltage of the main capacitor of the strobe is set to the first level at which the voltage does not fall below the flash-enabled voltage. and a second level that is higher than the first level, and if a shooting ready state is detected, the strobe is charged to a voltage that exceeds the second level. A charge control means is provided, and when the detection means detects a state in which photographing is not possible, charging of the main capacitor of the strobe is prohibited, and when a state in which photographing is possible is detected, charging of the main capacitor is prohibited. The built-in strobe is equipped with a charging control means that reduces the amount of strobe light emitted during sky photography, which may be done when photography is not possible, and also prohibits strobe light emission itself. It becomes possible to prevent wasteful energy consumption.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the main parts of an embodiment of the present invention, and FIG.
The figure also shows the strobe charging characteristics, Figure 3 is a vertical cross-sectional view of the cartridge chamber of the camera, and Figures 4 and 5 show the lens mount being attached to or detached from the camera body. The front view shown in FIG. 6 is a circuit diagram showing the main parts of another embodiment of the present invention. 6...Transistor, 12.13...
Comparator, 14-19... Resistor, 33...
...Transistor, 35...Switch circuit, 105...Patrone detection member, 106...
... Switch, 130 ... Lens attachment detection device. Patent applicant Canon Co., Ltd.

Claims (2)

[Claims] (1) A detection means for detecting whether the camera is in a shooting-capable state or a shooting-disabled state, and if the detection means detects a shooting-disabled state, the voltage of the main capacitor of the strobe enables the flash to emit light. The voltage is controlled so that the voltage is between a first level that does not fall below the voltage and a second level that is higher than the first level, and when a photographing possible state is detected, the second level A strobe photographing device comprising a charging control means for charging the strobe to a voltage exceeding . (2) A detection means for detecting whether the camera is in a shooting-capable state or a shooting-disabled state, and if the detection means detects a shooting-disabled state, prohibiting charging of the strobe's main capacitor. and charging control means for charging the main capacitor when a photographing enabled state is detected.