JPS639909Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an operation mode display device that displays the operating status of various magnetic recording and reproducing devices (hereinafter referred to as VTR) such as recording or battery alarm using a light emitting element or the like in the viewfinder of a video camera. By changing the display that differs depending on the VTR model to a common display, it is possible to
It is an object of the present invention to provide an operation mode display device that can be universally connected to a VTR and that can provide convenience to video camera users.

Conventionally, the display signal content of a recording display signal or a battery alarm display signal supplied from various VTRs to a video camera has varied depending on the model of the VTR. For example, some types of business VTR
In this case, the recording display signal from the VTR lights up the light-emitting display element (hereinafter referred to as LED) in the viewfinder of the video camera, and the battery alarm display signal from the VTR causes the LED to blink at a fixed period. Display signals are supplied from the VTR to the video camera via two transmission lines. This type of VTR is described below as the first type.
It's called a VTR. Alternatively, in the case of other types of professional VTRs, the display signal is not supplied from the VTR to the video camera, and the recording display LED is turned on by a processing circuit inside the video camera. this kind of
The VTR will hereinafter be referred to as a second type of VTR.

On the other hand, in some types of consumer VTRs, the above two display signals are supplied from the VTR to the video camera through a single transmission line, and as shown in Figure 1A, pulses of about 1Hz are sent at a level of +6V to +9V. A certain recording display signal causes the LED to blink, and when recording is stopped, +6V DC voltage is supplied to this LED.
Further, as shown in FIG. 1B, an LED other than the recording display LED is blinked by a battery alarm signal which is a pulse of about 1 Hz at a level of +9V.
This type of VTR will hereinafter be referred to as a third type of VTR.

Conventionally, recording display signals or battery alarm display signals supplied from various VTRs to video cameras have different contents depending on the VTR model.
It was not possible to commonly connect a VTR to a particular video camera. Furthermore, as mentioned above, for commercial use
The display of the VTR recording is indicated by the lighting of the LED,
On the other hand, the same display on a consumer VTR is shown by blinking LEDs, which has the disadvantage of causing confusion for video camera users.

The present invention eliminates the above-mentioned drawbacks, and one embodiment thereof will be described with reference to FIGS. 2A and 2B.

In this embodiment, it is assumed that the common display on the viewfinder of the video camera is that the recording is displayed by lighting an LED, and the battery alarm of the VTR is displayed by blinking the LED.

Furthermore, it is assumed that the first to third types of VTRs described in the conventional example are used as different types of VTRs.

FIG. 2A shows an embodiment of a switching circuit in the operating mode display device of the present invention, and FIG. 2B shows an embodiment of a battery alarm display circuit.

First, the switching circuit will be described. When the first type VTR is connected to a video camera, the movable contacts _of the slide switches _S1-1 to _{S1-3 are}
In this case, when the record start switch _S2 inside the video camera is turned on, the transistor _Q1 is turned on and its collector current flows through the resistors _R5 and _R6 . The collector voltage divided by the resistors _R5 and _R6 is connected to the slide switch _S1.
The signal is supplied from terminal ₁ through contacts c' and d of terminal 1 to a trigger signal input terminal (not shown) for starting recording of the VTR. In this way, the VTR starts recording.

On the other hand, a recording display signal is input from the VTR to terminal 2, and this signal is sent to the contacts of slide switches _{S1-3 .}
c', d are supplied to the base of transistor _Q2 via resistor _R8 . At the same time, this signal is supplied from terminal 3 via resistor _R7 to the internal circuit of the video camera as a recording start timing signal. Since the Zener diode _D3 with a constant voltage of 2.5V is connected to the emitter of the transistor _Q2 , for example, if the base voltage is 3.1V or higher, the transistor _Q2 is turned on. Since the voltage of the recording or rewind display signal from the terminal 2 is 5V, the transistor _Q2 is turned on, and the collector current of the transistor _Q2 flows through the resistors _R10 and _R11 . This current is the transistor
When supplied to the base of Q ₃ , transistor Q ₃ turns on and current flows between its emitter and collector. The collector current from this transistor Q ₃ is supplied to LEDL ₁ through resistor R ₁₂ and LEDL ₁
lights up. For displaying records in this way
LEDL ₁ lights up.

Next, when connecting the second type _of VTR to the video camera, slide switches S _1-1 to _{S 1-3}
The movable contact piece is connected to contacts b and c. As mentioned above, when switch S ₂ is turned on, switch S ₁ −
The divided collector voltage from terminal ₁ is supplied to the recording start trigger signal input terminal of the VTR through contacts b and c of terminal 1. In this way, the VTR starts recording. Furthermore, the collector current of the transistor _Q1 is connected to the resistor _R4 , the contacts b and c of the switch _{S1-2 ,} and the resistor _R8.
to the base of transistor _Q2 .
This current turns on transistor Q ₂ and transistor Q ₃ , so LEDL ₁ lights up. In this way, by turning on the switch S2, the recording or rewind display LED _L1 can be directly turned on without a recording signal being supplied from the outside via the terminal ₂ .

Next, when connecting a third _type VTR to a video camera, slide switches _{S1-1 to S1-3}
The movable contact of is in contact with the contacts a and c'. In this case, when the switch _S2 is turned on, the terminal 1
Since it is connected to the recording or rewinding start trigger input terminal of the VTR, this VTR recording or rewinding start trigger input terminal is connected to the contact _a of the switch _S1-1 .
c', diode _D1 and switch _S2 . Thus, in the third type VTR, recording is started when the recording start trigger input terminal becomes the ground potential. At the same time, the collector current of transistor _Q1 , which is turned on, flows through resistor _R4 , switch _{S1-2 , and}
through contacts a and c' and resistor _R8 to transistor _Q2
This current turns on transistors _Q2 and _Q3 , and the collector current from transistor _Q3 lights LED _L1 . In this way, the record indication LED is turned on without a record indication signal being supplied from the VTR. As explained in the prior art, the third type VTR used here supplies the signal shown in Fig. 1A as a record indication signal to the video camera over the same transmission line as the battery alarm signal shown in Fig. 1B, but in this embodiment, as described above, the record or rewind indication signal from input terminal 2 is cut off and switch _S2 is turned on so that current is supplied directly to LED _L1 inside the video camera.
Therefore, unlike the conventional example, LED _L1 does not blink when the signal shown in FIG. 1A is supplied, but lights up in the same way as in the other first and second types of VTR, so that the video camera user can make the same judgment as with other models and will not mistake it for a blinking battery alarm.

Next, the battery alarm display circuit shown in FIG. 2B will be explained. If the first type of VTR is connected to the video camera, terminal 5 has the first type.
A 1 Hz pulse of 0 to +9V is incoming as shown in Figure B.
This pulse is clipped by Zener diode D ₃ and resistor R ₁₃ to a level below the Zener voltage of 6 V, passes through capacitor C ₁ and then passes through transistor Q ₄ .
is applied to Transistor _Q4 alternately turns on and off in response to this pulse, collector current flows intermittently to transistor _Q5 , and transistor _Q5 also turns on intermittently.
Collector current flows intermittently through LEDL ₂ . In this way LEDL ₂ blinks.

Also, the second type of VTR does not provide a battery alarm signal to the video camera.

Furthermore, when a third type of VTR is connected to a video camera, the recording signal and battery alarm signal are supplied from the VTR to the video camera through the same transmission line, so they are input to terminal 5. The recording signal must be cut. +6V~ of the recording signal shown in Figure 1A that entered terminal 5
Pulses between +9V are clipped by the Zener diode _D3 and the resistor, and only the DC component between 0 and +6V is supplied to the capacitor _C1 . capacitor
Since C ₁ does not allow this DC component to pass through, no voltage is applied to transistor Q ₄ . Therefore,
Since transistors Q ₄ and Q ₅ are turned off, LEDL ₂
blinks and does not light up. In this way, the recording signal is transmitted over the same transmission line as the battery alarm signal.
Even if it is supplied from a VTR to a video camera,
Due to the above circuit configuration, the recording signal is cut off, and LEDL ₂ remains off. Further, when the battery alarm signal shown in FIG. 1B is supplied from the VTR to the video camera, it is exactly the same as the first type of VTR described above.

In this way, the switching circuit and battery alarm display circuit of the present invention can turn on LEDL ₁ during recording and flash LEDL ₂ when the VTR battery alarm occurs, regardless of the model of the VTR.

As mentioned above, the VTR mode display device according to the present invention includes a switching circuit that selectively outputs a recording signal from a recording start switch inside a video camera and a recording signal from a magnetic recording/reproducing device, and lights up a first display element. and a battery alarm display circuit that allows only pulses of a certain voltage or lower to pass among the signals from the magnetic recording/reproducing device to the video camera and cuts off the DC voltage signal to blink the second display element. Even if the display differs depending on the model, it can be made into a common display, making it possible to universally connect various VTRs to the camcorder, and allowing the user of the camcorder to clearly distinguish between lighting and blinking. It has the advantage that it is easy to determine whether recording has started or a battery alarm has occurred by yen classification.

[Brief explanation of the drawing]

Figures 1A and B are diagrams showing an example of a conventional recording start signal and battery alarm signal, Figures 2A and B
1 is a circuit diagram showing one embodiment of an operation mode display device according to the present invention. _R1 to _R18 ...Resistor, _Q1 to _Q5 ...Transistor,
S ₁ , S ₂ ... Switch, D ₁ ... Diode, D ₂ ,
D ₃ ... Zener diode, L ₁ , L ₂ ... light emitting element, C ₁ ... capacitor.

Claims (1)

[Scope of utility model registration request] In an operation mode display device installed in a video camera, the operation mode display device includes a first display element that displays a recording state of a magnetic recording and reproducing device, and a second display element that displays a battery alarm state of the magnetic recording and reproducing device. A switching circuit selectively outputs a recording signal from a recording start switch inside the camera and a recording signal from the magnetic recording/reproducing device to light up the first display element; An operation mode display device comprising: a battery alarm display circuit that causes the second display element to blink by passing only pulses of a certain voltage or less among the signals and cutting off the DC voltage signal.