JPS6235073Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) This invention relates to a photographing mode display device that displays the photographing mode of a camera on a panel.

(Prior art) In a camera that uses an auto-adjustable flash whose light output is controlled by a light intensity correction signal from the camera side, that is, an auto-adjustment signal, is the shooting mode MANUAL? It is necessary to indicate whether it is automatic (TTL/AUTO). Conventionally, such a display is performed on the camera side using a mechanical display board, as shown in FIG. However, since the camera side is equipped with many other operation display sections, the mechanical display board described above makes it difficult to understand the shooting mode display for those who are not familiar with operating the camera. . Furthermore, since the display switching operation is performed mechanically and must be provided within a limited space on the camera body, the installation position of the display board and the size of the display are also limited.

(Problem that the invention attempts to solve) Here, if the connection terminal that electrically connects the camera body and strobe is shared for the autoflash control signal and the shooting mode signal, the autoflash control signal will be output. Since the connection terminal voltage changes at this time, the shooting mode may be incorrectly displayed.

This invention has been developed in view of the above-mentioned circumstances, and it is an object of the present invention to provide a photographing mode display device that displays the photographing mode on a panel on the strobe side without error.

[Structure of the idea]

(Means for Solving the Problems) In this invention, when the shutter on the camera body side is released, the output of the circuit for determining the photographing mode is temporarily stored.

(Function) By temporarily storing (latching) the shooting mode discrimination output when the film is released after the shutter, an automatic light adjustment signal is output during this temporary storage, and the voltage of the terminal (J14) that connects the camera and strobe changes. Even if
The shooting mode display is not affected by this terminal voltage change.

(Embodiment) FIG. 2 shows an electric circuit of a strobe and a camera including a photographing mode display device according to this invention. When power switch S10 is turned on, capacitors C1 to C7 are charged to the polarities shown. When the synchro contact (X contact) S12 is turned on, the capacitor C3 is discharged. Then the thyristor
SCR1 is triggered and turns on. This SCR1
When the capacitor C4 is turned on, the capacitor C4 is discharged and the discharge tube 10 is triggered, and the capacitor C5 is also turned on.
is also discharged and thyristor SCR2 is turned on. Then, flash light is emitted from the discharge tube 10.

Now, press the shooting mode switch S1 on the camera side.
If 4a and S14b are turned off, that is, if the shooting mode is set to MANUAL,
The flash stop signal (automatic flash control signal) is not given from the camera side to the strobe side. Therefore, the strobe light emission state is full flash. On the other hand, when the switches S14a and S14b are turned on, that is, when the shooting mode is set to automatic (AUTO), the electromagnetic magnet that starts the film travel after the shutter is turned on.
When MG is off, a low level signal is applied from inverter IC2 to the base of PNP transistor Tr1. Then, transistor Tr1 is turned on, and capacitor C7 connects the collector-emitter circuit of transistor Tr1 and thyristor SCR3.
is discharged through the gate circuit. Then
SCR3 is turned on and capacitor C6 is charged.
Since SCR2 is reverse biased (forced commutation),
The SCR 2 is turned off and the discharge tube 10 stops emitting light.

The above is the operation of the automatic dimming strobe circuit shown in FIG. 2, but this strobe circuit itself is not the subject of this invention. Therefore, no further discussion of this circuit will be given. If the main parts of this invention are extracted from FIG. 2, it becomes as shown in FIG. 3. Here, the electromagnet MG is replaced by a resistor _RMG corresponding to its DC resistance. One end of the resistor _RMG is connected to the emitter of the transistor _Tr2 via the connection terminal J12.
The emitter of transistor _Tr2 is connected to its base via resistor R100. transistor
The base of Tr ₂ is connected to the Zener diode ZD through a series circuit consisting of resistors R102 and R104.
1 anode. zener diode
The cathode of ZD1 is connected to the emitter of transistor _Tr2 . This Zener diode ZD1 includes a capacitor C2, a liquid crystal display (LCD) 12
and latch/driver circuit 14 are connected in parallel.

As can be seen from Figure 2, the Zener diode ZD
1 is biased by the power supply current of the strobe circuit including SCR1 to SCR3, and provides a predetermined constant voltage across it. Thus, Zener diode ZD1 of FIG. 3 forms a constant voltage circuit that powers LCD 12, latch/driver circuit 14, resistors R100-R104, and transistor _Tr2 .
Power supply by this constant voltage circuit is performed by power switch S1.
0 (FIG. 2) is turned on.

The connection point between the resistors R102 and R104 is connected to the connection terminal J14 and the shooting mode changeover switch S14.
b to the other end of the resistor _RMG .
One end of the resistor _RMG connected to the connection terminal J12 is connected to the positive electrode of a battery B12 that supplies power to the shutter control circuit (FIG. 2) on the camera side. Further, the collector of an NPN transistor _Tr3 , which is turned on/off by the shutter control circuit, is connected to the other end of the resistor _RMG . The emitter of transistor _Tr3 is connected to the cathode of battery B12 via switch S16.

The collector circuit of the transistor Tr ₂ is coupled to the latch/driver circuit 14 . Also,
The junction of resistors R102 and R104 is coupled to latch/driver circuit 14 via inverter IC1. The signal applied to the latch/driver circuit 14 from the collector of transistor Tr ₂ is a latch signal LS which commands a latch memory within this circuit 14 to temporarily store. That is, when switch S14b is turned on (automatic mode) and transistor Tr ₃ and switch S16 are turned on (electromagnet MG is energized), transistor Tr ₂ is turned on and the output signal corresponding to the output signal of inverter IC1 is turned on. Information is temporarily stored in the latch memory. Depending on the signal derived from this latch memory, the LCD 12 displays the words "TTL AUTO" or "MANUAL" as shown in FIG.

The components R100, R102, R104,
R _MG , Tr ₃ and IC1 constitute a discrimination circuit 16 that discriminates the photographing mode from the electrical information generated at the connection terminals J12 and J14.

The circuit of FIG. 3 operates as follows.

(a) In manual mode.

In this case, switches S14a and S14b are turned off. Now, let the zener voltage of the zener diode ZD1 be _VZ , and the threshold voltage of the inverters IC1 and IC2 be _VC . Here, resistance R
The voltage _{drop V}
If the base-emitter threshold voltage V _BE of the inverters IC1 and IC2 is
The input voltage of , that is, the voltage drop V _T1 occurring across resistor R104 is V _T1 = R104/R100+R102+R104V
_Z …(1) becomes. If V _Z , R100 to R104, etc. are set so that V _T1 <V _C in manual mode, neither of the inverters IC1 and IC2 will turn on. That is, the output levels of inverters IC1 and IC2 both become high level. Then, since the transistor _Tr1 is not turned on, automatic light adjustment is not performed during strobe light emission, and full light is emitted. When the high level output of inverter IC1 at this time is given to the latch/driver circuit 14, LCD1
2 displays the mark "MANUAL". In addition, resistors R100 to R10 are set so that V _X <V _BE .
4 etc. are adjusted, so the transistor Tr ₂
is not turned on. Therefore, the latch signal
LS is not generated.

(b) In automatic mode.

In this mode, switches S14a, S1
4b is turned on, but the on/off state of switch S16 is not determined. That is, the circuit operation differs depending on whether the switch 16 is on or off.

(b-1) When switch S16 is turned off.

This is because the switching lever (not shown) on the camera side
This is the case when switching to TTL and the shutter button (not shown) has not yet been activated. In this case, transistor _Tr3 is turned off. Therefore, it can be considered that the transistor _Tr3 is electrically isolated from the resistor _RMG . The resistor R _MG is the DC resistance of the electromagnet MG, but generally speaking, R
_MG << (R100+R102). In this case, the voltage drop V _T2 occurring across the resistor R104 is V _T2 = R104/ _RMG + R104V _Z (2). Comparing V _T1 shown in equation (1) with V _T2 above, since R _MG <<(R100+R102), V _T2 >V _T1 . Therefore, the resistance R _M
By appropriately selecting _G , R104, etc., V
It is possible to set _T2 > V _C. Then, both inverters IC1 and IC2 are turned on, and their outputs become low level. Therefore, the transistor Tr ₁ becomes in a state where it can be turned on. However, the shutter button is not working yet, so SCR1 is off. Therefore, the transistor _Tr1 is not turned on, and the SCR3 is not turned on. On the other hand, the latch/driver circuit 14 displays "TTL" on the LCD 12 due to the low level output of the inverter IC1.
Display the "AUTO" mark.

(b-2) When switch S16 is turned on.

This occurs when the switching lever on the camera side is switched to TTL and the shutter button is pressed to start the shutter release operation. In this case, transistor _Tr3 is turned on. Now, the collector- _emitter saturation voltage V _CE(SAT
) is considered to be zero, and terminal J12 is considered to be at zero potential. If the voltage from the battery B12 is _VB , the emitter voltage of the transistor _Tr3 will be _-VB . Since the switch S14b and the transistor _Tr3 are turned on, the voltage at the terminal J14, that is, the input voltage to the inverters IC1 and IC2 becomes _-VB . Since the anode terminal voltage of the Zener diode ZD1 is -V _Z , the voltage drop V _T3 occurring across the resistor R104
is as follows: V _T3 = |V _Z −V _B | (3).

Here, the voltages V _Z and V _B are set so that V _T3 <V _C
is selected, both inverters IC1 and IC2 are turned off and their output level becomes high level. Therefore, the transistor _Tr1 is turned off again. Only when the electromagnet MG on the camera side is turned off, that is, when the transistor _Tr3 is turned off, the transistor _Tr1 is turned on by turning on the inverter IC2, and the flash light is adjusted. However, if this continues, the inverter IC1 will be turned off after this, its output will become high level, and the mark "MANUAL" will be displayed on the LCD 12 again. In order to avoid such erroneous display, the latch/driver circuit 14 is caused to perform a temporary storage operation by turning on/off the transistor _Tr2 .

When the transistor _Tr3 is on, the resistor R1
The voltage drop V _X1 at 00 is as follows: V _X1 = R100/R100 + R102V _B (4). Therefore, the resistance R is set so that V _X1 > V _BE.
100, R102 and voltage V _B are selected, transistor Tr ₂ can be turned on. In other words, the transistor Tr ₂ is turned on only when the shooting mode of the camera is "auto" and the shutter release electromagnet MG is energized (the transistor Tr ₃ is on). By turning on this transistor Tr ₂ , "TTL
AUTO” information can be loaded into the latch/driver circuit 14. Then, even if the output level of inverter IC1 changes from low level to high level, "TTL AUTO" continues to be displayed.

A brief summary of the main points of the operation sequence in automatic mode is as follows. (Switches S14a and S14b are on.) (i) Switch S16 off (ii) Inverter IC1, IC
2 on → "TTL AUTO" display (iii) Switch S16
On (iv) Inverter IC1, IC2 off → Strobe light emission starts (v) Electromagnet MG off (transistor Tr ₃ off) (vi) Inverter IC1, IC2 on → Strobe light emission stops.

FIG. 5 shows the internal structure of latch/driver circuit 14 shown in FIG. transistor
The collector of Tr ₂ is a D-type flip-flop (D-
FF)18 is connected to the clock input terminal CP. D
The output of the inverter IC1 is applied to the D input terminal of the -FF18. When the signal applied to the input terminal CP, that is, the latch signal LS, is at a low level, the signal level applied to the D input terminal appears at the output terminal Q as is. That is, the D-FF 18 does not perform a storage operation. On the other hand, when the latch signal LS is inverted from low level to high level, the D input terminal level immediately before this inversion is stored in the D-FF 18. That is, when the transistor _Tr2 is turned on, the output level of the inverter IC1 immediately before the transistor _Tr2 is turned on is latched, and this output level appears at the output terminal Q.

Signal L derived from output terminal Q of D-FF18
1 is inverted in level by the inverter IC3 and applied to the first input terminal of the EXOR gate 19 as the signal L2. Said signal L1 is also EXOR
It is applied to the first input terminal of gate 20. The second input terminals of EXOR gates 19 and 20 include an oscillator 2
A signal L3 of about 4 to several Hz is input. This signal L3 is further transmitted to the liquid crystal display sections 12 ₁ and 12 ₂
given at one end. Liquid crystal display section 12 ₁ and 12
₂ , output signals L4 and L5 of EXOR gates 19 and 20 are applied to the other ends of EXOR gates 19 and 20, respectively. In the circuit configuration shown in FIG. 5, the signal L4 goes high when the signals L2 and L3 are at opposite logic levels, and the signal L5 goes high when the signals L1 and L3 are at opposite logic levels. Since the signals L1 and L2 have opposite phases to each other, the signals L4 and L
5 is also in reverse phase. The signals applied to one end of the display devices 12 ₁ and 12 ₂ are the same L3, but the signals L4 and L5 applied to the other end are of opposite phase. Therefore, one of the displays 12 ₁ and 12 ₂ is in the display state, but both are not in the display state.

FIG. 6 is a timing chart showing the display states of the liquid crystal displays ₁₂₁ and ₁₂₂ . In the manual mode (MANUAL), the signal L1 is at a high level, as shown in FIG. At this time,
Since the signals L3 and L5 are in opposite phases, a potential difference is applied across the display ₁₂₂ in FIG. on the other hand,
Since the signals L3 and L4 are in phase, the display 12 ₁
No potential difference is applied between the two ends of the . Therefore,
Only the mark "MANUAL" is displayed on the display ₁₂₂ . Automatic mode (TTL
AUTO), the signal L1 is at low level. At this time, signals L3 and L5 are in phase,
Signals L3 and L4 have opposite phases. Therefore, only the mark "TTL AUTO" is displayed on the display ₁₂₁ .

The embodiments disclosed in this specification and illustrated in the drawings are not intended to limit the invention in any way. Various modifications are possible within the gist of this invention and the scope of the claims for utility model registration. for example
The character marks displayed on the LCD display panel 12 do not have to be in English. Further, this display panel may use LEDs or the like.
Further, the discrimination circuit 16 can be considered as a type of so-called level comparator, and various circuits are possible. For example, transistor Tr ₂ may be a P-channel enhancement mode MOS FET. The series resistance circuit consisting of resistors R100-R104 may also include a level shift circuit, such as a forward biased diode. Moreover, in the configuration of FIG. 5, the display devices 12 ₁ , 12
₂ can be made to blink at the oscillation cycle of the oscillator 24, but either one of these indicators may be in a continuous lighting state. Furthermore, as is clear from equation (4), since the voltage V _B of the battery B12 is used in the discrimination circuit 16, the deterioration of the battery B12 can be detected on the display panel 12 by detecting a decrease in the voltage V _B. It is also possible to display.

(Effect of the invention) Since the shooting mode discrimination output (output of IC1) is temporarily stored (latched) when the film is released after the shutter, the connection terminal (J14) is temporarily stored (latched) during this temporary storage.
Even if the voltage changes, the display 12 will not incorrectly display the photographing mode.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a shooting mode display board provided on the side of a normal camera, and Fig. 2 is a circuit showing an automatic light control flash including a shooting mode display device and an electrical system of the camera according to an embodiment of this invention. Figure 3 is a circuit diagram showing the main parts of this invention extracted from Figure 2, Figure 4 is a diagram illustrating a liquid crystal panel for displaying the shooting mode provided on the strobe side, and Figure 5 is a circuit diagram showing the main part of this invention taken out from Figure 2.
FIG. 6 is a circuit diagram illustrating the internal structure of the latch/driver circuit shown in the figure, and FIG. 6 is a timing chart illustrating the operation of the circuit shown in FIG. S10...Power switch (strobe side), S1
2... Synchro contact (X contact), S14a, S1
4b... Shooting mode changeover switch, S16... Switch (camera side), C1 to C7... Capacitor, SCR1 to SCR3... Thyristor, B10,
B12...Battery, IC1, IC2, IC3...Inverter, Tr1, Tr2...PNP transistor, Tr3
...NPN transistor, MG...electromagnet, J1
0, J12, J14... Connection terminal, ZD1... Zener diode (constant voltage circuit), 10... Discharge tube, 12... Liquid crystal display (LCD)/display panel, 14... Latch/driver circuit, 16... ...Discrimination circuit, 12 ₁ , 12 ₂ ...Liquid crystal display section, 18...
...D-type flip-flop (D-FF), 19, 20
...EXOR gate, 24...oscillator, LS...latch signal, L1 to L5...signal.

Claims (1)

[Claims for Utility Model Registration] (1) A state signal corresponding to the switching state of a switch element that opens and closes the current path of the electromagnet for locking the shutter rear film on the camera body side is sent to the camera body via the shooting mode changeover switch. and a device for controlling the strobe via the connecting terminal, wherein the strobe determines whether the photographing mode selection switch is open or closed via the connecting terminal. a circuit, a display section that displays a shooting mode based on the output of the discrimination circuit;
a latch circuit that temporarily stores the discrimination output of the discrimination circuit according to the state signal when the switch element performs switching for releasing the shutter rear film, and supplies the temporarily stored content to the display section; A shooting mode display device comprising: (2) The display unit includes a liquid crystal display panel that displays at least two types of marks indicating the shooting mode, and a driver circuit that drives the liquid crystal display panel in response to the discrimination output of the discrimination circuit. A photographing mode display device according to claim 1 of the patented utility model. (3) The photographing mode consists of two types, automatic mode and manual mode, and when the automatic mode is selected and the electromagnet is excited, the latch circuit outputs the discrimination output of the discrimination circuit. The photographing mode display device according to claim 1 or 2, wherein the photographing mode display device temporarily stores the following. (4) The display unit is powered by a constant voltage circuit that operates at the same time as a power switch on the strobe side is turned on. The shooting mode display device described in .