JPS60209726A - Automatic electric flash - Google Patents

Abstract

PURPOSE:To turn off a transmitting circuit system which transmits the turn-off signal of an electromagnetic coil for operating the shutter trailing curtain of a camera to the dimming circuit of the electric flash unless the electric flash is used by providing a gate circuit to the transmitting circuit system. CONSTITUTION:When a flash discharge tube device 40 is off, a signal for opening the gate circuit 23 of an electric shutter circuit 11 is not supplied to a terminal L and this gate circuit 23 is held in a cut-off state, so that a terminal T is not connected to an electromagnetic coil 21. Therefore, even if terminals G and T are connected mutually in this state through the internal circuit of the flash discharge tube device 40, no current flows through electromagnetic coil 21 and no disturbance occurs when the electromagnetic coil is turned off. Consequently, there is no delay in fast shutter photography and when the flash discharge tube device 40 is turned on, the gate circuit 23 is opened and a current path including the electromagnetic coil 21 is formed through the internal circuit of the flash discharge tube device 40, but a shutter speed is relatively slow, so there is almost no influence exerted upon the shutter speed.

Description

[Detailed description of the invention] 〔Technical field〕 This invention relates to an autostrobe.

[Prior art]

The electric shutter circuit of the aperture-priority automatic exposure camera 2 is provided with a circuit for setting a shutter speed according to the amount of incident light while the shutter is open, and a switching transistor in this shutter speed setting circuit is controlled. An electromagnetic coil is connected to this switching transistor and is energized or deenergized depending on the ON/OFF operation of this transistor.

The electromagnetic coil is provided in the shutter mechanism of the camera and closes the shutter when the electromagnetic coil is deenergized. Among such automatic exposure cameras, there are cameras that perform automatic light adjustment using an automatic flash tube device, that is, an automatic flash tube, at the same time as the electromagnetic coil is deenergized. In such cameras, the dimming signal connection terminal for supplying the deactivation signal of the electromagnetic coil to the strobe is connected to the switching transistor or electromagnetic coil directly or through a resistor, so the camera is connected to an electronic flash tube device. or when the connection terminal for the dimming signal and the ground terminal are short-circuited, current flows through the internal circuit of the electronic flash tube device or the ground terminal and the connection terminal for the dimming signal, causing the electromagnetic coil to There is a delay in deactivation and the shutter speed becomes too slow.

For this reason, the deactivation signal of the electromagnetic coil is only used when using the strobe. It is desirable to keep the transmission circuit system that transmits information to the dimmer circuit in a connected state, and to disconnect the transmission circuit system when the strobe is not in use.

[Purpose of the invention]

The object of the present invention has been achieved from the above viewpoint, and is a connection terminal that is attached to a camera and connects a shutter speed setting circuit within the camera and a connection terminal that sends the output of this circuit to the outside as a dimming signal. An object of the present invention is to provide an auto strobe having a function of controlling the connection state between the two.

〔Example〕

As shown in Fig. 1, an electric shutter circuit 1 of an automatic exposure camera
1 consists of a photometric circuit 11g and a shutter speed setting circuit 11b. That is, the output terminal of a light receiving element (for example, a silicon photodiode) 12 that converts the light incident while the shutter is open into an electrical signal is connected to the non-inverting and inverting input terminals of the operational amplifier 13. This amplifier 130
A parallel circuit including a capacitor 14 and a switch 15 is connected between the inverting input terminal and the output terminal. The switch 15 is opened in conjunction with the opening of the camera shutter. The output terminal of operational amplifier 13 is connected to the non-inverting input terminal of operational amplifier 16. The inverting input terminal of this amplifier 16 is connected to a reference voltage source 17, and the output terminal is connected to a PNP via a resistor 18.
) Runraster 190 paceni is connected. The emitter of this transistor is connected to the positive line 20a, and the collector is connected via the electromagnetic coil 21 to the negative line 20b.

The electromagnetic coil 21 is provided to operate a rear shutter curtain (not shown) of the camera. A connection point between the electromagnetic coil 21 and the collector of the transistor 19 is connected via a resistor 22 and a dart circuit 23 to a T terminal 24 as a dimming signal connection terminal. A control signal input terminal of the dart circuit 23 is connected to an L terminal 25 as a dart control connection terminal. The G terminal 26 serving as a grounding connection terminal is connected to the positive line 20a, and the X terminal 27 serving as a light emitting connection terminal is connected to the positive line 20m via a switch 28. Resistors 29 and 30.3 are connected between the positive and negative lines 20a and 20b.
1 series circuit is connected, and the anode of the photodiode 12 is connected to the connection point with the resistor 29.30.

Connection terminals on the camera side, i.e., X, G, L, T terminals 24
．． 25.26.27 is an electronic flash tube device 401)
G, L, T terminal 24h, 2S'h, '26a,
27h respectively. As shown in FIG. 2, the electronic flash tube device 40 includes a power supply circuit 41, a light emitting circuit 42. It is composed of a dimming control circuit 43 and a signal generation circuit 44. When a power switch (not shown) is turned on, this electronic flash tube device 40 connects the main capacitor ClO3 and the other capacitors ClO3 to ClO3.
O2, ClO3 ~ Cl0B, C112°C114, C1
16, C117, etc. are charged.

When the main capacitor ClO3 is charged to a predetermined voltage, the neon discharge tube B101 lights up, indicating that the flash is ready. In response to the lighting of this neon discharge tube B101, the transistor Q
105 becomes conductive.

When this transistor Q105 is in the OFF state, a relatively small current is supplied to the L terminal 25& through the resistor R106, and when it is ON, a relatively large current is supplied through the parallel resistance of the resistors R106 and R113. That is, currents of different levels are supplied to the L terminal 25ti depending on whether the transistor Q105 is turned on or off. The current supplied to the L terminal of the camera is supplied to the r-) circuit 23 of the electric shutter circuit 11 through the L terminal 25 of the camera, and this dart circuit 23 is in an open state, and the j5T terminal 24 connects the dart circuit 23. It is connected to the electromagnetic coil 21 via. In this state, when the button (not shown) of the camera release is pressed and the X and G terminals (synchro contacts) zv and te are short-circuited, the output terminal C116 of the light emitting circuit 42 in Fig. 2 is connected to the diode D.
11B-X, G terminal - Resistor R125 - Thyristor 5RI
Discharge through the r-to-cathode path of OI. As a result, the thyristor 5R101 becomes conductive and the capacitor C106
are thyristor SRI 01 and pulse transformer L102
0 through the primary winding. The discharge current of capacitor C106 induces a trigger voltage in the secondary winding of Norse transformer L1020. This trigger voltage is flash discharge tube V10
1 trigger electrode. At this time, the capacitor C107 is connected to the thyristor 5Rf (12 - resistor R114 - diode D109 - r- of main thyristor 8RJ04).
Discharge through the cathode path, main thyristor 5RJ-04
becomes conductive. As a result, the flash discharge tube v101 receives the charging voltage of the main canister ClO3 and emits light. When the light emitted by the flash discharge tube device 400 (and external light) is received by the light receiving element 12 of the electric shutter circuit 1 of the camera (FIG. 1), an output signal corresponding to the amount of light received is output from the operational amplifier 13. The output signal of this operational amplifier 13 is supplied to a reference signal source 170.
It is supplied to the operational amplifier 16 together with the reference signal. In this operational amplifier 16, the levels of the two signals are compared, and when the output signal of the amplifier 13 reaches a predetermined level, the amplifier 16
The output level of is inverted and transistor 19 becomes non-conductive. As a result, the electromagnetic coil 21 is deenergized, causing, for example, the rear curtain (not shown) of the shutter to run. This electromagnetic coil 1
2 is deenergized, a back electromotive force is generated in this electromagnetic coil, and this back electromotive force is supplied to the dart of the transistor Q104 of the flash discharge tube device 400 control circuit 43 via the dart circuit 23 and the T terminal ( Figure 2). This transistor Q104 becomes conductive, and an ignition current is supplied to the dart of the thyristor 5R103 through this transistor Q104. When this thyristor SR203 becomes conductive, the carrier A
? The discharge current of ClO3 is pulse transformer LJ 03
A trigger pulse is supplied to the trigger electrode of the arrester A101, and this arrester is ignited. As a result, the capacitor 4' ClO3 applies a reverse voltage to the main thyristor 8R104 via the arrester A101, causing the main thyristor to be cut off □.

As explained above, when synchronizing the flash discharge tube device and the camera, in response to the operation of the camera's release button,
When the G terminal is short-circuited, the flash discharge tube device starts emitting light, and in response to the incidence of an appropriate amount of light, the electromagnetic coil 2 is deenergized. The flash discharge tube device 400 stops emitting light. In an automatic exposure camera used in synchronization with such a flash discharge tube device, the flash discharge tube device and the camera are connected via a connection terminal, but when the power to the flash discharge tube device 40 is cut off, the flash discharge tube device 40 When it is in the non-operating state, the transistor Ql05 of the signal generation circuit 44 of the flash discharge tube device does not turn on, so a signal for opening the dart circuit 23 of the electric shutter circuit 11 is not supplied to the L terminal. Therefore, this dirt circuit 23 is maintained in a cut-off state and the T terminal is not connected to the electromagnetic coil 21.

Therefore, in this state, even if the G and T terminals are connected through the internal circuit of the flash discharge tube device 40, they are not connected to the electromagnetic coil 21, so this electromagnetic coil is connected to the internal circuit of the flash discharge tube device and the G and T terminals. Since no current flows through the electromagnetic coil, no disturbance (delay) occurs when the electromagnetic coil is deenergized.

Such a delay in the deenergization of the electromagnetic coil has a particularly large effect during high-speed shutter photography, but according to the present invention, no delay occurs during high-speed shutter photography. When the flash discharge tube device is put into operation, the dart circuit 23 is opened and a current path is formed in the electromagnetic coil 21 via the internal circuit of the flash discharge tube device, but in this case, the shutter speed is also relatively slow. Has almost no effect on shutter speed O In the above explanation, the case where a non-operating flash discharge tube device is connected to an automatic exposure camera is described, but even if the camera is not connected to a flash discharge tube device, the connecting terminal, i.e. G and T terminals may be short-circuited for some reason. However, in this case, since the L terminal is open, the ON signal is not supplied to the r-) circuit 23, and the gate circuit 23 is not opened. Therefore, even if the G and T terminals are short-circuited, the electromagnetic coil 2
1, no current path is formed and there is no delay in shutter speed.

Incidentally, the dirt circuit 23 used in the electric shutter circuit of the present invention may be one suitable for the above-mentioned operation, and one example is shown in FIG. According to the dart circuit in Figure 3, T terminal 2
5 is connected to the PNP (PNP) Range Meta 520 pace through a resistor 51. This transistor 520 pace is also connected through a resistor 53 to a positive line 54, which is connected through a resistor 55 to the emitter of transistor 52 and to the pace of a PNP lannostar 56. The collector of the transistor 56 is connected to the transistor 580 through a resistor 57 and the collector, and the emitter is connected to the negative 2 in 59. The emitter of transistor 58 is connected to positive line 54. PNP) Ranjistaro 0 and 61 pace is resistance 5
7 to the collector of the transistor 56.

The emitter of multi-collector PNP transistor 62 is connected to the positive line 54 via the collector-emitter path of transistor 60, the first collector is connected to the base of NPN transistor 630, and the second collector is connected to the base of NPN transistor 630.
Connected to transistor 640 pace. Transistor 620 is connected to negative line 59 via the collector-emitter path of NPN transistor 5. The transistor 650 pace is connected to the electromagnetic coil 2 through the resistor 22.
Connected to 1. The collector of the transistor 63 is the resistor 6
6 to the base of PNP transistor 670, and its emitter is connected to negative line 59. The emitter of transistor 67 is connected to the positive line and the collector is connected to resistor 6.
8 and NPN) are connected to the negative 2-in 59 via the collector-emitter path of the transistor 9. Further, the collector of the transistor 67 is connected to the T terminal 24.

In the dart circuit of FIG. 3, when a negative voltage is applied from the flash discharge tube device 40 via the L terminal 25, the transistor 5
2 conducts and then transistor 56 conducts. Therefore, transistors 511 and 60.61 become conductive. On the other hand, since a positive voltage is applied to the transistor 50, the transistor 65 is in a conductive state, so that the transistor 62 is conductive, and accordingly, the transistors 63 and 64 are conductive.

As a result, transistor 67 becomes conductive and transistor 69 becomes conductive.
is not conductive, and a positive voltage is applied to the T terminal 24.

In this state, when the electromagnetic coil 21 is deenergized and a back electromotive force is applied to the transistor 65, the transistor 65
Eventually, the transistor 67 becomes non-conductive, the transistor 69 becomes conductive, and a negative voltage is applied to the T terminal 24, and this negative voltage is applied as a dimming signal to the flash discharge device 4o.
The transistor Q104 (FIG. 2) of the control circuit 43 is made conductive.

〔Effect of the invention〕

As explained above, according to the present invention, a signal that controls the dart circuit provided between the shutter speed setting circuit in the camera and the connection terminal that sends the output of the shutter speed setting circuit to the outside as a dimming signal is provided. is output from the strobe according to the strobe's light emission preparation state, so that the dirt circuit can be brought into conduction only when the strobe is actually used.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an electric Kuyatta circuit for an auto-exposure camera attached to an auto-strobe according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of an auto-strobe? Figure 3 is a circuit diagram of a dart circuit used in an electric seven-layer circuit.

Claims (1)

[Scope of Claims] A photometric circuit, a shutter speed setting circuit that receives the output of the photometric circuit and controls the shutter closing timing, and a first connection that sends the output of the shutter speed setting circuit to the outside as a dimming signal. a dart circuit inserted between the terminal, the shutter speed setting circuit and the first connecting terminal, and a second connecting terminal connected to the r-) circuit and receiving a dart opening/closing control signal from the outside. a strobe attached to the camera, the third connection terminal being connected to the first connection terminal and accepting a dimming signal from the camera side, and a dimming control circuit connected to the third connection terminal; a signal generation circuit that detects a light emission preparation state and generates an r-1 opening/closing controllable electrical signal;
An autostrot characterized by comprising a fourth connecting terminal connected to the connecting terminal and transmitting the electric signal for controlling dart opening/closing to the camera side. .