JPH0265573A - Image pickup device - Google Patents

Abstract

PURPOSE:To simplify the constitution of a power supply section and a development section by varying an output voltage of a power supply section into two stages (high and low) in response to the presence of an external signal and allowing the image pickup section to turn on a switching element when a voltage of the power supply section is high and to turn off the switching element when the voltage is low. CONSTITUTION:When no external signal is fed to the power supply section 10, since a current flows to a power supply display circuit 21 of the image pickup section 20, a voltage drop takes place across a resistor R2 and an output voltage of the power supply section 10 is 9V, no current flows to a Zener diode ZD being a component of a driving circuit 26 and a transistor(TR) Q is kept in the off state. with an external signal applied to the power supply section 10, a relay RY is energized and a voltage of 14V is fed to the image pickup section 20, a current flows to the Zener diode ZD to turn on the TR Q. Thus, an operating voltage is supplied to a lighting circuit 23 and a development circuit 24 and then a video signal V is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an imaging device suitable for capturing an image of an object such as a person at any time in response to a door call signal or the like.

(Prior Art) FIG. 3 is a circuit diagram showing the configuration of a conventional imaging device of this type. In the figure, a power supply section 1 and an imaging section 2 are connected by a conductive wire of an appropriate length, and the imaging section 2 operates using the DC output voltage of the power supply section 1 as a power source.

Here, the power supply unit 1 is stabilized between terminals T1 and T12 by a power transformer 11 that steps down the commercial power supply voltage, a rectifier circuit 12 that rectifies its secondary output voltage, and capacitors C1 and C2 that smooth the rectified output. It is designed to generate a DC voltage of 14 [V], and further includes a pulse generation circuit 13 for superimposing a pulse signal on the conductor wire for supplying the DC voltage.

On the other hand, when a DC voltage is applied between the terminals T3 and 14 of the imaging unit 2, this DC voltage is supplied to the illumination circuit 23 and the imaging circuit 24 via the transistor Q as a switching element. .

In this case, a power supply display circuit 21 consisting of a resistor R1 and a light emitting diode LED connected in series is connected between the terminals T3 and T14, and the light emitting diode LED indicates that a DC voltage is being applied between these terminals. The drive circuit 22 also includes a drive circuit 22 for causing a base current to flow through the transistor Q in response to a pulse superimposed on the conductive wire, and for cutting off the base current, thereby turning on and off the transistor Q. It is possible to control the start and stop of imaging. Note that the illumination circuit 23 includes a large number of far-infrared LEDs connected in series, and a capacitor C3 for protecting the transistor Q is connected to both ends of the illumination circuit 23. Further, the imaging circuit 24 includes a well-known image sensor IS, and its video signal V is amplified by an amplifier 25 and supplied to a video device (not shown) from a terminal T5.

With this configuration, for example, when a switch or the like is pressed in response to a call from the doorbell, this is added to the pulse generation circuit 13 as an external signal S.

At this time, the pulse signal generation circuit 13 superimposes a pulse on the conductive wire for supplying the DC voltage. The drive circuit 22 detects this, turns on the transistor Q, and supplies operating power to the illumination circuit 23 and the imaging circuit 24. Therefore, the person who operates the doorbell can be displayed on a video device (not shown). In this state, when an external signal is again applied to the pulse generation circuit 13, the drive circuit 22 cuts off the base current of the transistor Q and stops the video operation due to the pulse generated in the same way from the pulse generation circuit 13. .

This imaging device has the advantage that by providing the pulse generation circuit 13 in the power supply section 1 and the drive circuit 22 in the imaging section 2, imaging control can be performed at any time without a dedicated signal line.

(Problems to be Solved by the Invention) The conventional imaging device described above has a configuration in which pulses are superimposed on a conductor for supplying DC voltage.
The configuration becomes complicated because a clock generation circuit is required inside the pulse generation circuit 13 and a counter etc. is required inside the drive circuit 22. Furthermore, the waveform and cycle of the pulses are easily disturbed by noise, and the power supply unit 1 and the imaging There was a problem in that the installation distance from part 2 was limited.

This invention was made to solve the above problems, and it is possible to simplify the configuration of the power supply section and the imaging section, and also,
An object of the present invention is to provide imaging devices that can extend their mutual installation distance.

[Structure of the invention]

(Means for Solving the Problems) The present invention includes an imaging unit having a switching element in a power path of an imaging circuit and an illumination circuit that illuminates an imaging target, and a power supply unit that supplies operating power to the imaging unit. In the image pickup device that takes an image by turning on a switching element of the image pickup section according to an external signal applied to the power supply section, the power supply section changes the output voltage in two stages, high and low, depending on whether or not the external signal is applied. and a drive means for turning on the switching element when the voltage of the power supply section is high and turning off the switching element when the voltage is low. be.

(Function) In the present invention, as the voltage switching means, for example, a circuit in which a resistor inserted in the voltage output circuit is short-circuited with the contact of a relay is used, and as the driving means, for example, a series circuit of a resistor and a Zener diode is used. The configuration can be simplified compared to conventional equipment that required a clock generation circuit and a pulse counting circuit, and the installation distance between the power supply section and the imaging section can be reduced because there is less influence of noise. Can be extended.

(Embodiment) FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, in which the same reference numerals as in FIG. 3 indicate the same or corresponding parts, respectively. Here, the power supply unit 10 includes a voltage switching circuit 14 in place of the pulse generation circuit 13 described above, and the imaging unit 20 includes a drive circuit 26 in place of the drive circuit 22 described above.

Of these, the voltage switching circuit 14 includes a resistor R2 inserted in the output path of the DC voltage, and a relay RY to which a normally open contact a is connected in parallel to the resistor and closes the contact a in response to an external signal. It is made up of. On the other hand, the drive circuit 26 consists of a series circuit of resistors R3 and R4 and a Zener diode ZD, both ends of which are connected to terminals T and 1, and a mutual junction of resistors R3 and R4 is connected to the base of the transistor Q. .

The operation of this embodiment configured as described above will be explained below.

First, when no external signal is applied to the power supply section 10,
Contact a of relay RY is open, and a DC voltage rectified and smoothed by rectifier circuit 12 and capacitors CI and C2 is supplied to imaging unit 20 via resistor R3. At this time, since current flows through the power supply display circuit 21 of the imaging unit 20, the issuing diode LED lights up to indicate that DC voltage is being supplied. Furthermore, as a result of current flowing here, the voltage drops across the resistor R2, and the output voltage of the power supply unit 10 is now 9 [V]. On the other hand, the Zener voltage of the Zener diode ZD constituting the drive circuit 26 is 9.
If 5 [V] is used, the resistances R2 and R
9 [■] in the series circuit of Q and Zener diode ZD
No current flows in this circuit even if a voltage of
The voltage between the emitter and base of transistor Q is zero, and transistor Q is kept in an off state. Therefore, operating power is not supplied to the illumination circuit 23 and the imaging circuit 24.

Next, when an external signal is applied to the power supply unit 10, the relay RY
is excited, its contact a is closed, and resistor R2
Short-circuit both ends. As a result, a voltage of 14 [V] is supplied to the imaging section 20.

At this time, the light emitting diode LED of the power supply display circuit 21 continues to be lit. On the other hand, in the drive circuit 26, a current flows through the Zener diode ZD, and a voltage generated across the resistor R3 is applied between the emitter and base of the transistor Q, turning on the transistor Q. Therefore, the operating voltage is supplied to the illumination circuit 23 and the imaging circuit 24, thereby obtaining the video signal V.

Note that the external signal continues to be applied to the voltage switching circuit 14 while a switch (not shown) is kept pressed, and when the switch is released, the external signal disappears and the relay RY returns to normal.
The output returns to the initial state of 9 [V].

FIG. 2 is a time chart showing these relationships. That is, when commercial power supply voltage is supplied to the power supply section 10 at time t1, a DC voltage of 9 [V] is output from the power supply section 10, and in response to this, the LED of the power supply display circuit 21 lights up, indicating that the power supply is turned on. Show that it has been established. Then, at time t
When the external signal S is applied to the voltage switching circuit 14 for a period of 0 from t3 to t3, the power supply section 10 outputs a DC voltage of 14 [V] during this period, and as a result, the lighting circuit 23 and the imaging circuit 24 operate and the terminal The video signal V is output to T5. Then, when the voltage supply to the power supply section 10 is cut off at time t4, the output voltage becomes zero, and the LE of the power supply display circuit 21
D is also turned off.

Thus, according to this embodiment, the output voltage of the power supply unit 10 can be switched to two high and low levels depending on the presence or absence of an external signal, and furthermore, the transistor Q can be controlled to be turned on or off depending on the level of this voltage. As a result, the same operation as the conventional device can be performed with a simple circuit configuration.

In this case, the influence of noise is also less likely.

In addition, in the above embodiment, a case was explained in which an external signal is applied to the voltage switching circuit 14 while a switch (not shown) is kept pressed, but it is also possible to connect a capacitor or the like in parallel to the relay RY to make it an off-delay relay. Therefore, even if you immediately release your hand from the switch, it is possible to obtain a video signal for a certain period of time.

Furthermore, although the above embodiment describes an imaging device used in a doorbell, the present invention is not limited thereto, and may be applied to an imaging device having a switching element in the power supply path of an imaging circuit and a lighting circuit that illuminates the imaging target. and a power supply unit that supplies operating power to the imaging unit, and includes a monitoring imaging device or V
It can also be applied to TR.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the configuration can be simplified compared to conventional devices that required a clock generation circuit and a pulse counting circuit, and the power supply section is less affected by noise. Also, there is an effect that the installation distance between the imaging units can be extended.

FIG. 3 is a circuit diagram showing the configuration of a conventional imaging device.

10...Power supply section, 11...Power transformer, 12...
- Rectifier circuit, 14... Voltage switching circuit, 20... Imaging section, 231... Power supply display circuit, 23... Lighting circuit,
24...Imaging circuit, 26...Drive circuit.

Claims (1)

[Claims] It has an imaging section having a switching element in a power supply path of an illumination circuit that illuminates an imaging circuit and its imaging target, and a power supply section that supplies operating power to this imaging section, and the In an imaging device that captures an image by turning on a switching element of an imaging section, the power supply section includes a voltage switching means for changing an output voltage in two steps of high and low depending on the presence or absence of the external signal, and the imaging section is connected to the power supply section. turning on the switching element when the voltage is high;
An imaging device comprising: a drive means for turning off the switching element when the voltage is low.