JP2004045864A - Electronic flash device for camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic flash device for camera which permits selection of a light emission source to be supplied to a discharge tube according to the shutter speed of a focal plane shutter in flat emission. <P>SOLUTION: The electronic flash device is characterize by having: a first light emitting means for allowing the discharge tube 12A to emit light by using a main capacitor 17; a second light emitting means for allowing the discharge tube 12A to emit light a plurality of times by using a battery 100 and an oscillation transformer 240; the focal plane shutter; and a control means 130 for performing control so as to allow the discharge tube 12A to emit light by using the first light emitting means when the exposure time for taking a photograph is longer than the electronic flash synchronization time of the focal plane shutter and to allow the discharge tube to emit light by using the second light emitting means when the exposure time is shorter than the electronic flash synchronization time. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a strobe device for a camera, and more particularly, to a strobe device for a camera having a normal strobe light emission function and a flat light emission function.
[0002]
[Prior art]
As is well known, when a strobe device is used in a camera having a focal plane shutter, if the exposure time for photographing is faster than the flash synchronization time of the focal plane shutter, the energy stored in the condenser is gradually reduced. The so-called flat light emission, which emits light from an Xe tube (xenon discharge tube) continuously for a certain period of time and irradiates a subject by intermittent emission, is used.
[0003]
[Problems to be solved by the invention]
By the way, in the flat light emission, while a front curtain and a rear curtain of a focal plane shutter are moving while forming a slit for exposure, a small amount of light emission must always be continued a plurality of times. In order to use the stored energy, sufficient charge must be stored in this capacitor, and it takes some time to charge the charge. Therefore, there is a possibility that a shutter chance may be missed when waiting for the time until charging is completed.
[0004]
If the guide number is increased by the flat light emission as described above, the capacity of the capacitor itself must be increased, and as a result, the size of the camera may be increased.
[0005]
A first object of the present invention has been made in view of the above problems, and when an exposure time is faster than a flash synchronization time of a focal plane shutter, a battery mounted on a camera without using a capacitor. An object of the present invention is to provide a strobe device for a camera that can emit strobe light at the time of photographing.
[0006]
A second object of the present invention is to provide a strobe device for a camera, which can select a light emission source to be supplied to a discharge tube according to a shutter speed of a focal plane shutter.
[0007]
Means and Action for Solving the Problems
In order to achieve the above object, a strobe device for a camera according to the present invention includes a discharge tube that emits a strobe light for irradiating a subject, and a discharge tube that emits light by the energy stored in a main capacitor. A light emitting means, a second light emitting means for causing the discharge tube to emit light a plurality of times using only the battery without using the main capacitor, a focal plane shutter, and an exposure time for photographing of the focal plane shutter. At the time of strobe synchronization, and at a later time than the strobe synchronization second, the light emission of the discharge tube is performed using the first light emitting means, and the exposure time for photographing is set at the strobe synchronization time of the focal plane shutter. And control means for controlling the discharge tube to emit light by using the second light emitting means. And butterflies.
[0008]
Further, a strobe device for a camera according to the present invention, in a camera having a focal plane shutter, includes an oscillation transformer and a discharge tube which emits light in synchronization with the cycle of the oscillation transformer, and provides an exposure time for photographing. Is faster than the flash synchronization second of the focal plane shutter, the light emission control is continued while the exposure is being performed.
[0009]
Further, a strobe device for a camera according to the present invention, in a camera having a focal plane shutter, a discharge tube that emits strobe light for irradiating a subject, a first light emitting unit that emits light from the discharge tube, A second light emitting means for causing the discharge tube to emit light, wherein when the exposure time for photographing is later than the flash synchronization time of the focal plane shutter and the flash synchronization time, the first light emission means is provided. When the exposure time for photographing is faster than the flash synchronization time of the focal plane shutter, light is emitted by the second light emitting means. Is a means for supplying energy stored in the capacitor to emit light, and the second light emitting means emits light in conjunction with the cycle of the oscillation transformer. Characterized by a means.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an external perspective view of a camera having a strobe device according to a first embodiment of the present invention as viewed obliquely from the upper right, and FIG. 2 is a cross-sectional view taken along line II-II ′ of FIG. FIG. 3 is a perspective view schematically showing the internal configuration of FIG.
[0011]
The flash device of the camera according to the first embodiment is an embodiment for achieving the first object of the present invention.
[0012]
As shown in FIG. 1, a lens barrel 8 having a photographic optical system for capturing an image of a subject is disposed in the center of the front surface of an exterior housing 1 that forms a camera body. A finder window 4 for optically observing the camera is provided, and a flash emission window 3 for irradiating a subject with flash light is provided diagonally above and to the right of the lens barrel 8. I have.
[0013]
A release button 5 for starting photographing is provided on the left side of the upper surface of the camera exterior housing 1. A zoom button 6 for driving the lens barrel 8 to set a subject to an arbitrary photographing magnification is provided.
[0014]
In the first embodiment, the length of the camera exterior housing 1 in the longitudinal direction is defined as “l”.
[0015]
As shown in FIG. 2, the lens barrel 8 is disposed at the center in the camera exterior housing 1 so as to be movable in the optical axis direction 0. On the left side, a film cartridge room 9 is provided. The spool chamber 7 for film winding is disposed on the right side, and a focal plane shutter 10 is disposed on the rear side.
[0016]
Further, as shown in FIG. 3, a finder optical system 4a including a finder window 4 is disposed above the lens barrel 8, and the finder optical system 4a is located on the right side of the finder optical system 4a. A strobe light emitting unit 3a including the strobe light emitting window 3 is provided at a position on the upper right side of the front surface of the camera exterior housing 1. Further, on the back of the strobe light emitting unit 3a, the entire driving device of the camera is provided. A battery 11 for supplying power is provided.
[0017]
As shown in FIG. 4, the strobe light emitting portion 3a is formed by a reflector 15, a light-emitting discharge tube (hereinafter, referred to as Xe tube) 12, an electrode terminal 13 of the Xe tube, and an outer wall of the Xe tube 12. The reflection umbrella 15 is for reflecting light emitted from the Xe tube 12 toward a predetermined irradiation range, and the Xe tube 12 is The light emission is started by a control signal from a control circuit 30 (see FIG. 5) described later.
[0018]
In the first embodiment, the length in the longitudinal direction of the Xe tube is defined as “m”.
[0019]
FIG. 5 is an electric circuit diagram showing a light emitting circuit of a strobe device for a camera according to the first embodiment of the present invention, and FIG. 6 is a timing chart of operation of each part of the light emitting circuit shown in FIG. .
[0020]
As shown in FIG. 5, the light emitting circuit includes a power supply battery 20, a control circuit 30 having switching output terminals ST1 and ST2, and a voltage measurement terminal VB, switching elements 40 and 50 including FETs and the like, A primary winding 61, a second primary winding 62, a first secondary winding 63 having a larger number of turns than the primary winding, a number of turns of the primary windings 61 and 62, and a first 2 An oscillation transformer 60 including a second secondary winding 64 as a trigger coil having a larger number of turns than the number of turns of the next winding 63, and the Xe having a transparent electrode (trigger electrode) 71 applied to the surface thereof It is composed of a tube 12.
[0021]
A series connection circuit of the first primary winding 61 and the switching element 40 and a series connection circuit of the second primary winding 62 and the switching element 50 are connected to the power supply battery 20 in parallel. ing.
[0022]
Further, the Xe tube 12 filled with Xe gas is connected in parallel to both ends of the first secondary winding 63, and the output end of the second secondary winding 64 is The Xe tube 12 is connected to a trigger electrode 71 on the outer wall.
[0023]
Further, the output terminal ST1 of the control circuit 30 is connected to the gate terminal of the switching element 40, and the output terminal ST2 is connected to the gate terminal of the switching element 50.
[0024]
Next, a flat light emitting operation of the strobe light emitting circuit thus configured will be described with reference to a timing chart of FIG.
First, when a release signal is input to a CPU (not shown) by a pressing operation of the release button 5 in FIG. 1, the camera enters a shooting state (see FIG. 6A). At the same time, an ON signal “H” (high) is output from the output terminal ST1 of the control circuit 30 shown in FIG. 5 (see FIG. 6B), the switching element 40 is turned on, and the current from the power battery 20 Flows to the switching element 40 through the first primary winding 61.
[0025]
When a current flows through the primary winding of the transformer 60, electric energy is generated in the primary winding, and the electric energy is transmitted to the secondary winding 63 by an electromagnetic induction action.
[0026]
The magnetic energy transmitted to the secondary winding 63 is converted into electric energy, and energy is generated from the secondary winding 63 toward the second secondary winding 64. At this time, the voltage of the lower end 63a (in FIG. 5) of the first secondary winding 63 becomes the lowest, and the voltage of the upper end 64b (in FIG. 5) of the second secondary winding 64 becomes It is in the highest state. In this state, since no current flows through the Xe tube 12, the resistance value becomes infinite, and the output side of the secondary winding 63 is in a high impedance state.
[0027]
In this state, electric energy is generated in the secondary winding in a direction opposite to the current flowing through the primary winding 61 and converted into a voltage, so that the upper end of the first secondary winding is turned on. A high voltage is generated at 63b (in FIG. 5), and an upper end 64b (in FIG. 5) of the second secondary winding is higher than a voltage generated at an upper end 63b of the first secondary winding. Even higher voltages are generated. Therefore, a high voltage is applied to the trigger electrode 71 on the outer wall of the Xe tube 12 to excite the Xe tube 12 (see FIG. 6D).
[0028]
Here, since the Xe tube 12 cannot be excited only by the switching element 40, an off signal “L” (low) is output from the output terminal ST1 (see FIG. 6B), and at the same time, an on signal is output to the output terminal ST2. "H" is output (see FIG. 6C). Then, the current flowing through the switching element 40 and the first primary winding 61 is turned off, and the switching element 50 conducts, so that the current from the battery 20 flows through the second primary winding 62. It flows to the switching element 50.
[0029]
When a current flows through the primary winding 62, electric energy is generated in the primary winding, and the electric energy is transmitted to the secondary winding 64 by an electromagnetic induction action.
[0030]
The magnetic energy transmitted to the secondary winding 64 is converted into electric energy, and energy is generated from the secondary winding 64 toward the second secondary winding 63. Here, the current flowing through the second primary winding 62 flows in a direction opposite to the direction of the current flowing through the first primary winding 61 described above. Also in the energy generated at 64, the energy is generated in the direction opposite to that when the ON signal is output from the output terminal ST1. Then, a high voltage whose sign is opposite to that when the ON signal is output from the output terminal ST1 is applied to the trigger electrode 71 on the outer wall of the Xe tube 12 (see FIG. 6D).
[0031]
As described above, the ON signal “H” is alternately output from the output terminals ST1 and ST2 of the control circuit 30 an arbitrary number of times (see FIGS. 6B and 6C), so that the Xe gas in the Xe tube 12 is in an excited state. And the resistance decreases. When the resistance value decreases, the resistance value at both ends of the first secondary winding 63 decreases, and the current Ixe (see FIG. 6E) tends to flow through the Xe tube 12. As described above, since the output terminals ST1 and ST2 of the control circuit 30 alternately repeat the output of the ON / OFF signal, the current Ixe flowing through the Xe tube 12 also changes with the output of the ON / OFF signal of the output terminal. The flowing direction is reversed (see FIG. 6-e).
[0032]
Then, as the resistance value of the Xe tube 12 decreases, a current Ixe flows from both ends of the first secondary winding 63, and the Xe tube 12 emits light. When the Xe tube 12 emits light, the impedance on the secondary winding side of the transformer 60 also decreases, so that the current flowing on the primary winding side of the transformer 60 sharply increases. Therefore, when the current of the primary winding increases, the voltage of the power supply battery 20 changes. This voltage is monitored by the VB measurement terminal of the control circuit 30 to confirm light emission (see FIG. 6G), and the output cycle of the on / off signals of the output terminals ST1 and ST2 is gradually changed according to the voltage of the battery 20. (See FIGS. 6B and 6C).
[0033]
When the strobe circuit is controlled in this manner, a certain amount of light can be emitted from the Xe tube 12 a plurality of times from when the front curtain of the focal plane shutter opens until the rear curtain blocks light (FIG. 6). e, f). When light emission of the Xe tube 12 is started and a light emission stop signal is output from the control device (not shown) to the control circuit 30, both outputs of the output terminals ST1 and ST2 of the control circuit 30 are connected. The light is turned off (see FIGS. 6B and 6C), and the light emission is stopped (see FIG. 6E).
[0034]
As described above, in the strobe device for a camera according to the first embodiment of the present invention, since no condenser is used for light emission of the Xe tube, the camera exterior housing can be formed small and cost reduction can be achieved. Can be achieved.
[0035]
If the exposure time for shooting is faster than the flash synchronization time of the focal plane shutter, the Xe tube is emitted directly from the battery via the oscillation transformer, so that flat emission is performed to uniformly illuminate the subject. be able to.
[0036]
FIG. 7 is a perspective view of a camera having a strobe device according to a second embodiment of the present invention as viewed obliquely from the upper right, and FIG. 8 is a cross-sectional view taken along line IX-IX ′ of FIG. FIG. 9 is a perspective view schematically showing the internal configuration of FIG.
[0037]
The flash device of the camera according to the second embodiment is an embodiment for achieving the second object of the present invention.
[0038]
In the strobe device of the second embodiment, the outline of the camera exterior housing and the internal configuration of the camera are almost the same as those of the first embodiment shown in FIGS. A main capacitor for a strobe is provided, and a strobe circuit is provided which can select a means for directly supplying luminous energy to be supplied to the Xe tube from a power supply battery and a means for charging the main capacitor and supplying luminous energy to the Xe tube. The difference is that they are set. Therefore, only this difference will be described, and the same reference numerals will be given to the same components as those in the first embodiment, and description thereof will be omitted.
[0039]
As shown in FIGS. 8 and 9, the strobe main condenser 17 is disposed inside the camera exterior housing 1 to the left of the patrone room 9. Therefore, when the main condenser 17 is disposed in the camera exterior housing 1 in this manner, the length of the camera exterior housing 1 in the longitudinal direction is “l ′”, and the camera defined in the first embodiment is “1 ′”. The length is longer than the length “l” of the exterior housing 1 in the longitudinal direction.
[0040]
FIG. 10 is a cross-sectional view showing the structure of the strobe light emitting section 3a of FIG. 9, but if the strobe main condenser 17 is provided, a large amount of light can be emitted. The length of the strobe light emitting portion 3a in the longitudinal direction is longer than the length "m" of the Xe tube 12 shown in FIG. Becomes longer.
[0041]
FIG. 11 is an electric circuit diagram showing a light emitting circuit of a strobe device for a camera according to a second embodiment of the present invention. FIG. 12 shows a charging operation for a main capacitor in the light emitting circuit shown in FIG. FIG. 13 is a timing chart for explaining a flat light emitting operation of the light emitting circuit shown in FIG. 11, and FIG. 14 is a timing chart for explaining a light emitting operation by the main capacitor of the light emitting circuit shown in FIG. It is a timing chart.
[0042]
As shown in FIG. 11, the strobe light emitting circuit according to the second embodiment includes a power supply battery 100, a control circuit 130 having output terminals 140, 150, 160, and 170, charging switching elements 200 and 230, An oscillation transformer 240 including a first primary winding 241, a second primary winding 242, and a secondary winding 243, a bridge diode 250, a light emission switching relay switch 260, a resistor 110, The switching element 120, the trigger capacitor 290, the trigger coil 280 composed of the primary winding 281 and the secondary winding 282, the main capacitor 17 for the strobe, and a transparent electrode (trigger) The Xe tube 12A is coated with an electrode (electrode) 301.
[0043]
The power supply battery 100 includes a series connection circuit of the first primary winding 241 of the oscillation transformer 240 and the charging switching element 200, and a second primary winding 242 of the oscillation transformer 240. A series connection circuit of the charging switching elements 230 is connected in parallel.
[0044]
The gate terminal of the charging switching element 200 is connected to the output terminal 150 of the control circuit 130, and the gate terminal of the charging switching element 230 is connected to the output terminal 140 of the control circuit 130. The two ends of the secondary winding 243 of the oscillation transformer 240 are connected to the input terminal of the bridge diode 250.
[0045]
The output terminal of the bridge diode 250 has a series connection circuit of the light emission switching relay switch 260 and the strobe main capacitor 17, a series connection circuit of the Xe tube 12A and the light emission switching element 120, and a resistor 110 And a series circuit of the trigger capacitor 290 and the primary winding 281 of the trigger coil 280 are connected in parallel.
[0046]
The control terminal of the light emission switching relay switch 260 is connected to the output terminal 160 of the control circuit 130, and the gate terminal of the light emission switching element 120 is connected to the output terminal 170 of the control circuit 130. Furthermore, a connection point between the resistor 110 and the trigger capacitor 290 is connected to a connection point between the Xe tube 12A and the light emitting switching element 120.
[0047]
Next, an operation of charging the main capacitor of the strobe light emitting circuit configured as described above will be described with reference to time charts of FIGS.
In the initial state, when an ON signal “H” is output from the output terminal 160 of the control circuit 130 (see FIG. 12B), the light emission switching relay switch 260 closes, and the main capacitor 17 is charged. Becomes possible.
[0048]
Next, when an ON signal “H” is output from the output terminal 150 of the control circuit 130 (see FIG. 12C), the first primary winding 241 of the oscillation transformer 240 is output from the power supply battery 100. Then, a current flows through the charging switching element 200.
[0049]
When a current flows through the first primary winding 241, electric energy is generated in the primary winding, and the electric energy is transmitted to the secondary winding 243 of the oscillation transformer 240 by electromagnetic induction. The magnetic energy is converted into electric energy by the secondary winding 243, and a current flows through the secondary winding 243. This current is converted to a direct current by the bridge diode 250 and stored as charge in the main capacitor 17 and the trigger capacitor 290.
[0050]
When the release of the energy generated by the first primary winding 241 ends, the ON signal from the output terminal 150 of the control circuit 130 is turned off (see FIG. 12C), and at the same time, the control circuit 130 An ON signal is output from the output terminal 140 (see FIG. 12D).
[0051]
When an ON signal “H” is output from the output terminal 140, a current flows from the battery 100 to the second primary winding 242 of the oscillation transformer 240 and the charging switching element 230.
[0052]
When a current flows through the second primary winding 242, electric energy is generated in the primary winding, and the electric energy is transmitted to the secondary winding 243 of the oscillation transformer 240 by an electromagnetic induction action. The magnetic energy is converted into electric energy by the secondary winding 243, and a current flows through the secondary winding 243, and the current is accumulated in the main capacitor 17 and the trigger capacitor 290 via the bridge diode 250.
[0053]
In this way, by alternately turning on and off the output terminals 150 and 140 of the control circuit 130, the charging switching elements 200 and 230 are alternately turned on and off (see FIGS. 12C and 12D), and the main capacitor 17 is turned off. Then, charges are accumulated in the trigger capacitor 290 and charged. Then, when the charging voltage (V) of the main capacitor 17 reaches the predetermined voltage (Va) (see FIG. 12-e), the output from the control circuit 130 is stopped. Thereafter, an off signal “L” is output from the output terminal 160 of the control circuit 130 (see FIG. 12B), the light emission switching relay switch 260 is opened, and the charging operation is completed. Note that the output terminal 170 of the control circuit 130 is kept off during the charging period (see FIG. 12A).
[0054]
Next, a flat light emission operation (light emission operation when a small amount of light is required) of the strobe circuit according to the second embodiment of the present invention will be described with reference to the time charts of FIGS.
After the completion of the charging of the capacitor described with reference to FIG. 12, when a release signal is input to a CPU (not shown) by the pressing operation of the release button 5 in FIG. 7 (see FIG. 13A), the output of the control circuit 130 is output. While the terminal 160 remains off (see FIG. 13-b), an on signal is output from the output terminal 170 (see FIG. 13-e), and in response to this on signal, the light emitting switching element 120 is turned on. Then, the electric charge accumulated in the trigger capacitor 290 flows through the light emitting switching element 120 and the primary winding 281 of the trigger coil 280.
[0055]
When a current flows through the primary winding 281 of the trigger coil 280, electric energy is generated in the primary winding 281, and energy is transmitted to the secondary winding 282 of the trigger coil 280 by an electromagnetic induction action, and Is converted to The secondary winding 282 is connected to the trigger electrode 301 on the outer wall of the Xe tube 12A. Since the Xe tube 12A has a very high resistance value, the secondary winding 282 is connected to the secondary winding 282 of the trigger coil 280. The transmitted electric energy is converted into a voltage, and a high voltage is applied to the outer wall 301 of the Xe tube 12A.
[0056]
When a high voltage is applied to the trigger electrode 301 on the outer wall of the Xe tube 12A, xenon gas inside the Xe tube is excited, the insulation resistance is reduced, and a current flows. At this time, when an ON signal is output from the output terminal 150 of the control circuit 130 (see FIG. 13C), energy is generated in the first primary winding 241 of the oscillation transformer 240 as described above, and Energy is transmitted to the next winding 243, and a current Ixe flows through the bridge diode 250 to the Xe tube 12A (see FIG. 13-f). When a current flows through the Xe tube 12A, the Xe tube 12A emits light.
[0057]
Since the energy generated in the first primary winding 241 of the oscillation transformer 240 is small, the time during which the Xe tube 12A emits light is short (see FIGS. 13C and 13F).
[0058]
Therefore, at the same time as turning off the output terminal 150 of the control circuit 130, an on signal is output from the output terminal 140 (see FIGS. 13C and 13D). This time, the second primary winding of the oscillation transformer 240 is turned on. At 242, energy is generated, and the energy is transmitted to the secondary winding 243.
[0059]
By alternately turning on and off the output terminals 150 and 140 of the control circuit 130, the first primary winding 241 and the second primary winding 242 of the oscillation transformer 240 alternately generate energy. (See FIGS. 13C and 13D), the current Ixe flows through the Xe tube 12A (see FIG. 13F), and from when the front curtain of the focal plane shutter opens until the rear curtain blocks light. During this time (see FIGS. 13g and 13h), a fixed amount of flat light emission can be performed a plurality of times from the Xe tube 12A.
[0060]
Since the flat light emission does not use the electric charge charged in the main capacitor 17, the light emission amount is small, and this light emission amount is defined as "n".
[0061]
When the flat light emission reaches a predetermined time, the output terminals 150 and 140 of the control circuit are both turned off to stop the light emission (see FIGS. 13C, 13D and 13F). Note that the output terminal 160 remains off during the flat light emission (see FIG. 13B).
[0062]
Next, a light emitting operation in the case of emitting a large amount of light in the strobe light emitting circuit according to the second embodiment will be described with reference to time charts of FIGS.
After the charging described in FIG. 12 is completed, when a release signal is input to a CPU (not shown) by the pressing operation of the release button 5 in FIG. 7 (see FIG. 14A), the output terminal 160 of the control circuit 130 When an ON signal is output (see FIG. 14-b) and the light emission switching relay switch 260 is turned on, the main capacitor 17 and the Xe tube 12A are brought into conduction.
[0063]
When an ON signal is output from the output terminal 170 in this state (see FIG. 14E), the light emitting switching element 120 is turned on in response to the ON signal, and the electric charge stored in the trigger capacitor 290 is reduced. , The light emitting switching element 120 and the primary winding 281 of the trigger coil 280.
[0064]
When a current flows through the primary winding 281 of the trigger coil 280, the electric energy of the primary winding 281 is transmitted to the secondary winding 282 of the trigger coil 280, and the secondary winding 282 is connected to the Xe tube. Since the Xe tube 12A is connected to the trigger electrode 301 on the outer wall of the outer wall 12A and has a very high resistance value, the electric energy transmitted to the secondary winding 282 of the trigger coil 280 is converted into a voltage. A high voltage is applied to the trigger electrode 301 on the outer wall of the Xe tube 12A.
[0065]
When a high voltage is applied to the trigger electrode 301 on the outer wall of the Xe tube 12A, the xenon gas inside the Xe tube is excited, the insulation resistance is reduced, and the electric charge accumulated in the main capacitor 17 is applied to the Xe tube 12A. It flows as a current Ixe through the light emitting switching element 120 (see FIG. 14-f). When a current flows through the Xe tube 12A, the Xe tube 12A emits light.
[0066]
In this way, a large amount of light can be emitted from the Xe tube 12A from when the focal plane shutter is opened until the light is shielded (see FIG. 14-g).
[0067]
Since the large amount of light is emitted by the electric charge charged in the main capacitor 17, if this amount of light emission is defined as n ', it is larger than the amount of light emission n during the flat light emission (see FIG. 13). n ′ increases and the light emission amount increases.
[0068]
When the emission of the large amount of light reaches a predetermined time, the output terminal 170 of the control circuit 130 is turned off to stop the emission (see FIGS. 14E and 14F). The output terminals 150 and 140 of the control circuit 130 remain off during this light emission (see FIGS. 14C and 14D).
[0069]
As described above, in the flash device according to the second embodiment of the present invention, when the exposure time for photographing is faster than the flash synchronization time of the focal plane shutter by switching on / off of the light emission switching relay switch 260. When the exposure time for photographing is performed without using the main condenser 17 and the exposure time for photographing is slower than the flash synchronization time of the focal plane shutter and the flash synchronization time, the main condenser 17 is used. , And the main light emission can be performed. Even after flat light emission is performed prior to main light emission, a large amount of light can be emitted because the charge of the main capacitor does not decrease.
[0070]
In the second embodiment of the present invention, when the exposure time for photographing is faster than the flash tuning time of the focal plane shutter, flat light emission is performed without using a main condenser. In the case where flat emission is performed when the exposure time for shooting is later than the flash synchronization time of the focal plane shutter, and when the flash synchronization time is longer than the flash synchronization time, the flat emission is performed using the main condenser. Of course, it is possible to provide a strobe device for a camera capable of selecting a light-emission supply source to be supplied to the discharge tube according to the shutter speed of the focal plane shutter.
[0071]
Further, if flat light emission is performed when the exposure time of the shutter is later than the flash synchronization time as described above, there is no need to wait for the charging time.
[0072]
【The invention's effect】
As described above, according to the present invention, when the exposure time is faster than the flash synchronization time of the focal plane shutter, a strobe that can emit flat light only with a power supply battery without using a main capacitor that requires a charging time is used. A device can be provided, and the possibility of missing a photo opportunity can be reduced.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a camera having a strobe device according to a first embodiment of the present invention, as viewed obliquely from the upper right side;
FIG. 2 is a sectional view taken along the line II-II ′ of FIG. 1;
FIG. 3 is a perspective view schematically showing the internal configuration of FIG. 1;
FIG. 4 is a cross-sectional view showing the structure of the strobe light emitting unit of FIG.
FIG. 5 is an electric circuit diagram showing a light emitting circuit of the strobe device according to the first embodiment of the present invention;
6 is a timing chart of the operation of each part of the light emitting circuit shown in FIG. 5,
FIG. 7 is an external perspective view of a camera having a flash device according to a second embodiment of the present invention, as viewed obliquely from the upper right side;
8 is a sectional view taken along line IX-IX 'of FIG.
FIG. 9 is a perspective view showing the outline of the internal configuration of FIG. 7;
FIG. 10 is a sectional view showing the structure of the strobe light emitting unit of FIG. 9;
FIG. 11 is an electric circuit diagram showing a light emitting circuit of a strobe device according to a second embodiment of the present invention;
12 is a timing chart illustrating a charging operation of a main capacitor in the light emitting circuit illustrated in FIG. 11;
13 is a timing chart illustrating a flat light emitting operation in the light emitting circuit shown in FIG. 11;
FIG. 14 is a timing chart illustrating a main light emitting operation in the light emitting circuit illustrated in FIG. 11;
[Explanation of symbols]
10. Focal plane shutter
20, 100 ... battery (second light emitting means)
30, 130... Control circuit (control means)
60, 240 ... oscillation transformer
12, 12A: light-emitting discharge tube (Xe tube)
17 Main capacitor (first light emitting means)

Claims (4)

A discharge tube that emits strobe light for illuminating the subject,
First light emitting means for causing the discharge tube to emit light by energy stored in the main capacitor;
Second light emitting means for causing the discharge tube to emit light a plurality of times by using only the battery without using the main capacitor;
A focal plane shutter,
When the exposure time for photographing is later than the flash synchronization time of the focal plane shutter and the flash synchronization time, the light emission of the discharge tube is performed using the first light emitting means. When the exposure time is faster than the flash synchronization time of the focal plane shutter, control means for controlling the discharge tube to emit light using the second light emitting means,
A strobe device for a camera, comprising: In a camera having a focal plane shutter,
An oscillation transformer, and a discharge tube that emits light in conjunction with the cycle of the oscillation transformer,
If the exposure time for photographing is faster than the flash synchronization time of the focal plane shutter, the flash control for the camera is continued during the exposure. In a camera having a focal plane shutter,
A discharge tube that emits strobe light for irradiating a subject, a first light emitting unit that emits light from the discharge tube, and a second light emitting unit that emits light from the discharge tube;
When the exposure time for photographing is later than the flash synchronization time of the focal plane shutter and the flash synchronization time, the first light emitting unit emits light, and the exposure time for photographing is A strobe device for a camera, wherein the second light emitting means emits light when the speed is faster than the flash synchronization time of the focal plane shutter. The first light emitting means is a means for supplying energy stored in a capacitor to emit light, and the second light emitting means is a means for emitting light in synchronization with a cycle of an oscillation transformer. A strobe device for a camera according to claim 3.

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