JP2885376B2 - Lens device for TV camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens device for a television camera, and more particularly to a lens device for a television camera that suppresses an overcurrent during power supply.

[Conventional technology]

The aperture, zoom and focus of the lens for an EFP (Electric Field Production) television camera are provided with servo circuits for position control and speed control, each of which is driven by a DC motor.

Therefore, the current capacity required for the EFP type TV camera lens is larger than that of a general small lens.

The ENG (Electric News Gathering) television camera is equipped with a DC power supply as an accessory to supply the DC power required by the camera.

Recently, there have been many cases where an EFP-type TV camera lens is mounted on an ENG-type TV camera for use. In connection with this, the electric circuit of the EFP-type TV camera lens is connected to the ENG-type TV camera's electric circuit. In addition, the DC power supply attached to the ENG type TV camera has been used as the operation power supply for the lens for the EFP type TV camera.

[Problems to be solved by the invention]

Since the current capacity required by the ENG TV camera itself is not so large, the attached DC power supply capacity is not large either. Therefore, when the EFP-type TV camera lens is attached to the ENG-type TV camera and the DC power supply is used as a common power supply, and the DC power supply is turned ON to be used as the power supply of the EFP-type TV camera lens, the EFP-type TV camera Overcurrent flows because the load capacity of the lens is large.

For this reason, the breaker attached to the DC power supply may be activated, which may cause a problem when used as a power supply for a lens for an EFP television camera.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lens device for a television camera which can use a camera DC power supply as a lens DC power supply, excluding the above-mentioned drawbacks.

[Means for solving the problem]

In order to achieve the above-mentioned object, the present invention provides a television camera lens device including a drive circuit including a servo circuit for driving each mechanism such as a zoom mechanism, wherein the drive circuit is divided into a plurality of groups, And a delay circuit for supplying power in a time-series manner.

[Action]

As shown in FIG. 1, each load circuit in the lens was divided into a plurality of groups, and a delay circuit was provided for each of the groups.
Each load circuit operates in time series based on the time constant of the delay circuit.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an electric circuit when an EFP type television camera lens according to the present invention is mounted on an ENG type television camera class camera.

The camera 21 of the ENG type television camera class is provided with an electric circuit 4 for the camera.
And a breaker 6.

The EFP type television camera lens 20 is composed of a zoom and focus drive servo circuit 1, an aperture drive servo circuit 2, a general circuit 3, and delay circuits 7 and 8 provided on the input sides of the three circuits. Electrical circuit.

Although the circuit configuration of the delay circuits 7 and 8 is the same, each has a time constant determined by a capacitor and a resistor constituting the circuit. For example, the delay circuit shown in FIG. 2 is used.

In FIG. 2, the transistor 34 is turned on based on a time constant determined by a capacitor and a resistor provided on the input side, and operates the relay 35.

Therefore, when the camera DC power supply 5 is turned on, current is first supplied to the camera electric circuit 4, then current flows to the aperture servo circuit 2 and the general circuit 3 according to the timed characteristic of the delay circuit 7, and finally, the delay Zoom according to the timed characteristic of circuit 8
A current is supplied to the focus servo circuit 1. That is,
The transient current supplied from the DC power supply 5 is selected by selecting the time constants of the delay circuits 7 and 8 so that the current is supplied to the next circuit when the peak value of the transient current supplied from the DC power supply 5 has attenuated. Can be suppressed, and the breaker 6 does not need to be operated.

If the required current capacity of the diaphragm servo circuit 2 and the general circuit 3 is smaller than the capacity of the DC power supply 5, and it does not matter if a DC current is supplied simultaneously with the camera electric circuit 4, the delay circuit is used. 7 can be omitted.

That is, the number of delay circuits and the time constant of the delay circuits are selected by comparing and examining the DC power supply capacity and the load capacity of the camera and the lens.

Although the delay circuits 7 and 8 in FIG. 1 are connected in series, the peak value of the transient current is suppressed by connecting them in parallel and then making the time constant of the delay circuit 8 larger than the delay circuit 7. Is also possible.

〔The invention's effect〕

As described above, by providing a plurality of delay circuits in the electric circuit of the lens for the EFP television camera, the peak value of the transient current generated by the DC power supply attached to the camera of the ENG television camera class can be time-series. Can be suppressed.

Therefore, the breaker does not turn off when the camera-side DC power is turned on, and the photographing operation can be performed without any trouble.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electric circuit when an EFP type TV camera lens is mounted on an ENG type TV camera class camera, and FIG. 2 is an electric circuit diagram of a delay circuit. DESCRIPTION OF SYMBOLS 1 ... Zoom / focus servo circuit, 2 ... Aperture servo circuit, 3 ... General circuit, 4 ... Camera electric circuit, 5 ... DC power supply, 6 ... Breaker, 7,8 ... Delay circuit, 34 ... Transistor, 35 ... relay.

Claims (1)

(57) [Claims] 1. A television camera comprising a television camera main body having a power supply and a lens detachably mounted on the television camera main body, and a driving circuit including a servo circuit for driving each mechanism such as a zoom mechanism on the lens side. In the lens device, the drive circuit is divided into a plurality of groups, and when power is supplied from the power supply to each of the groups, when the peak value of the transient current supplied to one group circuit attenuates, the next group is formed. A lens device for a television camera, wherein a delay circuit for supplying power in time series is provided in the circuit.