JPS6035100Y2 - level display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a level display device for a video signal, etc. in a video camera connected to a portable VTR or the like.

2. Description of the Related Art Conventionally, video cameras are known in which a meter or a portion of a cathode ray tube monitor screen is used as a display for setting an aperture.

The present invention uses light emitting diodes arranged in a row to display a video signal level for, for example, aperture setting, and as shown in the figure, means 2 for rectifying a video signal from an image pickup tube via a terminal 1; A plurality of comparators C1, C2, C3, C4, and C5 each compare the level of this rectified signal with a plurality of reference levels, and each light emitting diode LED l emitted by the output of these comparators, respectively. LED 2, LE
D3.

LED4. LED 5, and a constant current power source (terminals indicated by 3) that supplies a current for light emission to these light emitting diodes, and a voltage lower than the level of the rectified signal that allows some of the light emitting diodes to emit light. diodes D in turn to other light emitting diodes that can be emitted at a level of
I, D2. It is configured to be able to supply current from the constant current power supply via D3tD4.

4 is a power supply terminal that applies a reference level voltage to the comparator, and resistors R1, R2, R3, R4, R
A voltage divided by 5 and R6 is applied.

In the display device in such a video camera, the means 2
When the level of the signal from R1 to R6 becomes higher than any of the voltages divided by the resistors R1 to R6, the corresponding comparator is activated, and the light emitting diode can emit light by the output of the activated comparator. When the output level of the means 2 is at a level that operates the comparators C3, C4, C5, the voltage of the constant current power supply is applied to the diodes DI, D2 . and light emitting diode L
This applied voltage turns on the diode DLD2 and the light emitting diode LED3, and a current flows from the constant current power supply to the light emitting diode LED 3 via the diodes Di and D2, and the light emitting diode LED 7 The light emits light.

A voltage at both ends when the light emitting diode LED3 is turned on is applied to both ends of the diode D3 and the light emitting diode LED 4 which are connected in series, and with this applied voltage, the light emitting diode LED 4 and the diode D3 are turned on. Therefore, even if the comparator C4 operates, the light emitting diode LED4 does not emit light.

Similarly, the diodes D3 are connected in series. The voltage across the light emitting diode LED 3 that is turned on is applied across D4 and the light emitting diode LED 5, and with this applied voltage, the light emitting diode LED 5 and
Diode D 3 * D 4 may turn on, so even if comparator C5 operates, light emitting diode L
ED5 does not emit light.

In this way, the output level of the means 2 is the comparator C3,
When the level is such that C4 and C5 are operated, only the light emitting diode (LED3) emits light.

It is preferable that the five light emitting diodes LED1 to LED5 are arranged in a line to indicate, in order, that the level of the signal from the means 2 is excessive, slightly excessive, appropriate, slightly insufficient, and insufficient.

Further, it is desirable that the level width of the video signal emitted by the light emitting diode LED 3 to display an appropriate level is narrower than that of other light emitting diodes.

In order to make the level width of the video signal emitted by each light emitting diode different, the voltages divided by the resistors R1 to R6 should be made non-uniform, or the video signal or the signal from the means 2 should be passed through a non-linear system. This can be done by

As described above, this invention includes a rectifying means for rectifying an input signal such as a video signal whose level is to be displayed, a level setting means for setting a plurality of reference levels, and a level setting means for rectifying an input signal such as a video signal whose level is to be displayed, and a level setting means for setting a plurality of reference levels. , separate comparators for respectively comparing the plurality of reference levels set by the level setting means, and separate light emitting diodes each having one pole connected to the output side of each of these comparators;
A level display device comprising a power source that supplies current for light emission to these light emitting diodes, and configured such that a light emitting diode connected to the comparator emits light by a comparator that operates according to the level of the input signal, A constant current power source is used as the power source, and the other pole of any light emitting diode among the light emitting diodes (hereinafter referred to as a first light emitting diode) to which the voltage from the constant current power source is applied, and the first A current from the constant current power source is connected to the other pole of the second light emitting diode connected to the comparator whose reference level is next lower than the reference level of the comparator to which the light emitting diode is connected. A diode to be supplied to the second light emitting diode is connected, and when the first light emitting diode emits light, the forward resistance of the diode blocks the flow of the current that causes the second light emitting diode to emit light. Accordingly, it is possible to obtain a level display device having a simple configuration and an inexpensive price, in which only a single light emitting diode among the plurality of light emitting diodes described above emits light according to the level of the signal.

[Brief explanation of drawings]

The figure is a circuit diagram showing an embodiment of the present invention. 2: Rectifying means, 3: Constant current power supply terminal, 01-C5:
Comparator, LED1 to LED5: light emitting diode,
D1 to D4: diodes.

Claims (1)

[Claims for Utility Model Registration] 1. A rectifying means for rectifying a human signal, a level setting means for setting a plurality of reference levels, and a level of a signal rectified by the rectifying means and a level set by the level setting means. Separate comparators for comparing each with a plurality of reference levels, separate light emitting diodes each having one pole connected to the output side of each of these comparators, and a power supply supplying a current for emitting light to these light emitting diodes. and a level display device configured such that a light emitting diode connected to the comparator emits light by a comparator that operates according to the level of the input signal,
A constant current power source is used as the power source, and the other pole of any light emitting diode among the light emitting diodes (hereinafter referred to as a first light emitting diode) to which the voltage from the constant current power source is applied, and the first A current from the constant current power source is connected to the other pole of the second light emitting diode connected to the comparator whose reference level is next lower than the reference level of the comparator to which the light emitting diode is connected.
Connect the diodes that supply the light emitting diode ratio of the first
1. A level display device characterized in that when the second light emitting diode is emitting light, the forward resistance of the second light emitting diode prevents the current emitted by the second light emitting diode from flowing out. Request for registration of a utility model for arranging 25 light emitting diodes in a row and displaying whether the level of the rectified video signal is excessive, slightly excessive, appropriate, slightly insufficient, or insufficient by lighting these light emitting diodes. The level display device according to item 1. 3. Scope of Utility Model Registration Claim 1, Paragraph 1: The level width of the rectified video signal that lights up the light emitting diode that indicates the appropriate level among the light emitting diodes is small compared to the level width that lights up the other light emitting diodes. The level display device described in .