JPH08125894A - Fan controller for television camera - Google Patents

Abstract

PURPOSE: To evade the intrusion of a rain drop into a housing, and to prevent an obstacle to an electric circuit or the cloudiness of a lens surface. CONSTITUTION: A cooling fan 12 and a motor 13 for introducing fresh air are arranged at the camera housing 10, and a temperature sensor 15 and a control part 18 are arranged in its inside, and a rain drop sensor (or humidity sensor) 16 is arranged at its outside. Then, the control part 18 actuates the fan 12 when it is detected that the temperature of the inside of the housing 10 becomes higher than the prescribed temperature by the temperature sensor 15, and in addition, a rainfall state is not detected by the rain drop sensor 16. Accordingly, at the time of the raifall state, the fan 12 is stopped, and the intrusion of the rain drop is evaded. Besides, when the temperature of the inside of the housing 10 becomes higher than the prescribed temperature in spite of the raifall state, the fan 12 can be controlled and switched (reverse rotation) as to attain internal circulation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control content of a device for driving and controlling a fan for cooling the inside of a housing of a television camera.

[0002]

2. Description of the Related Art Television cameras are used in a system which is directly operated by a photographer or a system which is remotely mounted by being mounted on a pan head, and is often used in all weather regardless of whether it is sunny or rainy. ing. In this type of TV camera, a cooling fan is installed to reduce the temperature rise inside the housing due to the heat generated by the circuit members, driving members, etc. The temperature inside the camera housing is maintained within a predetermined temperature by the circulation type).

[0003]

However, in the above-mentioned conventional television camera, since the miniaturization has been promoted, the cooling effect tends to be deteriorated due to a narrow space in the housing. In recent years, high-definition (HDTV
-The number of TV cameras for high definition TV) is increasing, but this high-definition camera has a higher heat generation amount than the conventional camera for NTSC (National Television System Committee), and it has a higher temperature Since it is delicate, it is necessary to improve cooling efficiency. Therefore, in order to improve the cooling efficiency in such a fan control device, it is conceivable to adopt an outside air circulation system that takes in outside air instead of the inside air circulation system.

However, in this outside air circulation system, when it rains, raindrops (including those in the form of mist) enter the inside of the housing when the outside air is taken in, and the electric circuit (photographing circuit) or the like is damaged. And the inner surface of the lens tends to be fogged, which affects the image quality. In particular, when a strong wind blows at the same time as rain, the influence on the obstruction of the photographing circuit and the fogging of the lens surface becomes great.

The present invention has been made in view of the above problems, and an object of the present invention is to control a fan for a television camera capable of preventing raindrops from entering, preventing obstacles to an electric circuit and fogging of a lens surface. To provide a device.

[0006]

In order to achieve the above object, the invention according to the first aspect of the present invention is a television camera fan control device for driving and controlling a fan for taking in outside air into a housing of a television camera. Is provided, and when the rainfall state is detected by the rainfall detection sensor, the fan is controlled to be stopped. According to a second aspect of the present invention, a temperature sensor for detecting the temperature inside the housing of the television camera is provided, and when a predetermined temperature is detected by the temperature sensor and the rainfall state is not detected by the rainfall detection sensor, The feature is that the fan is operated. According to a third aspect of the present invention, when the predetermined temperature is detected by the temperature sensor and the rainfall state is detected by the rainfall detection sensor, the fan is controlled to be switched to the inside air circulation. To do.

[0007]

According to the structure of the first aspect, as the rainfall detection sensor, a raindrop sensor for directly detecting the fall of raindrops, a humidity sensor for detecting a rain state equivalent to rain (a rain state), or the like is used. It can be used, and when the rainfall condition is detected by the rainfall sensor, the driving of the cooling fan is stopped. It is conceivable that the fan is automatically driven and controlled, for example, at all or partial times during the operation of the camera, and the driven fan is stopped. In addition,
When it rains, the outside air temperature drops, so the temperature inside the housing also drops and the need for cooling decreases.

According to the structure of the second aspect, the fan drive control is performed by both the temperature sensor and the rainfall state detection sensor, so that the temperature inside the camera housing becomes equal to or higher than the predetermined temperature and the rainfall occurs. Only when it is not in the state, the fan is driven to take in outside air. Therefore,
In this case, the fan drive is stopped not only when it is raining, but also when the inside of the housing is below a predetermined temperature, and there is an advantage that cooling by the fan is performed efficiently.

Further, according to the structure of the third aspect, when the temperature inside the housing does not drop in spite of the rainy state, the inside air is circulated by rotating the fan in the reverse direction. Therefore, it is possible to cool the inside of the housing while preventing the entry of raindrops. In this case, since the outside air temperature is lowered by rain, the cooling effect can be expected even in the inside air circulation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of a television camera fan control device according to the first embodiment, and FIG. 2 shows the circuit configuration of a control unit. In FIG. 1, the television camera is configured such that a lens portion (not shown) is housed in a housing 10 and an image is taken from a window portion.
As shown in the figure, the fan 12 is arranged together with the motor 13, and the exhaust hole 14 is provided therein. Further, a temperature sensor 15 is provided at a predetermined position in the housing 10, and a raindrop sensor 16 is provided as a rainfall detection sensor on the upper surface of the housing 10 at a position where raindrops can be received. Like the raindrop sensor applied to an automobile, the raindrop sensor 16 receives a raindrop on a detection member and measures a change in an electric resistance value of the detection member (which may be a value of another electric element). It is to detect rainfall.

Further, a control unit 18 is provided in the housing 10, and the control unit 18 drives and controls the motor 13 of the fan 12 based on the detection outputs of the temperature sensor 15 and the raindrop sensor 16. The detailed configuration of the control unit 18 is shown in FIG. 2. Inside the control unit 18, a comparator 20 that inputs the detection output of the temperature sensor 15, an inverter 21 that inputs the detection output of the raindrop sensor 16, and the above An AND circuit 22 for inputting the outputs of the comparator 20 and the inverter 21, a driving transistor 23 for inputting the output of the AND circuit 22 to a base terminal, and a relay operated by the driving transistor 23 and serving as an operation switch of the motor 13 ( Electromagnetic relay) circuit 24 and power supply 2
5 are provided.

That is, a voltage obtained by dividing the driving voltage VD by the resistors R1 and R2 is applied to the non-inverting input terminal of the comparator 20 as a reference voltage Vref, and the reference voltage Vref detects a temperature of 40 degrees. The output voltage corresponding to the detected temperature is supplied from the temperature sensor 15 to the inverting input terminal. Therefore, in this comparator 20, the output voltage of the temperature sensor 15 is the reference voltage V
When it exceeds ref, that is, the temperature inside the housing 10 is 40
Outputs a High signal when the temperature exceeds the limit. The raindrop sensor 16 outputs a High signal when a rain condition (raindrop) is detected, and outputs a Low signal when a rain condition is not detected. The output of the raindrop sensor 16 is inverted by the inverter 21. Is output.

Further, in the AND circuit 22, both input signals are Hi.
When it is a gh signal, that is, when the temperature inside the housing 10 is 40 ° C. or more and it is not raining, a logical product is taken and a High signal is output to the driving transistor 23. Then, the driving transistor 23 is turned on when the High signal is input, whereby the coil of the relay circuit 24 is operated and the operation switch of the motor 13 is turned on.

The first embodiment has the above construction, and its operation will be described below. For example, when the weather is fine during shooting with a television camera, the raindrop sensor 16 does not detect a rainy state, and the output of the inverter 21 becomes a high signal. When the temperature sensor 15 does not detect that the temperature is equal to or higher than the predetermined temperature, that is, 40 ° C. or higher, a Low signal is output. Therefore, the output of the AND circuit 22 is a Low signal, and the driving transistor 23 is turned off Fan 1
The second motor 13 is not activated.

Then, when the weather is fine, the temperature sensor 15
When it is detected that the temperature is equal to or higher than the predetermined temperature, a High signal is output, and the AND condition is satisfied in the AND circuit 22 and the drive transistor 23 is turned on.
Therefore, the motor 13 is moved by the relay circuit 24, and the fan 12 is rotationally driven. As a result, as shown by the flow of the arrow in FIG. 1, the outside air is taken in from the fan 12, the outside air circulates in the housing 10, and then is exhausted from the exhaust holes 14, so that the inside is efficiently cooled. To be done.

After that, when it starts to rain during shooting,
Since the raindrop sensor 16 detects the rainfall state, the output of the inverter 21 becomes a low signal, and the AND circuit 22 does not satisfy the AND condition. Therefore, the drive transistor 23 is turned off, the relay circuit 24 is disconnected, and the motor 13 is stopped, so that raindrops do not enter the inside of the housing 10 together with the outside air. As a result, it is possible to prevent the electric circuit in the housing 10 from being adversely affected and the inner surface of the lens from being fogged. In addition, since the outside temperature decreases due to rainfall, the temperature inside the housing 10 also gradually decreases, and it is not necessary to operate the fan.

FIGS. 3 and 4 show the configuration of the second embodiment, which is a combination of the outside air circulation and the inside air circulation. In FIG. 3, the housing 12 is provided with the fan 12 and the motor 13 similar to those in FIG. 1, but an opening / closing valve 29 is arranged in the exhaust hole 14, and the opening / closing valve 29 opens when the fan 12 sucks, Close when exhausting. A humidity sensor 30 is provided as a rainfall detection sensor on the top surface of the housing 28. The humidity sensor 30 is, for example, a combination of a conductive material and a polymer composite material, and is used in a VTR (Video Tape Recording) device. It is similar to the sensor. That is, the humidity sensor 30 has, for example, a structure in which a resistance film in which carbon powder is dispersed in a hydrophilic resin is applied on an alumina substrate on which a comb-shaped electrode is printed, and the resistance value is a predetermined value in a high humidity region. It is possible to determine a rainfall state equivalent to rainfall by detecting that the rainfall has changed.

Further, a control unit 31 shown in FIG. 4 is provided, and in addition to the control of the first embodiment, this control unit 31 detects when it is raining and when the temperature inside the housing 28 is above a predetermined temperature. At this time, the motor 13 is driven in reverse. That is, as shown in the figure, the detection output of the humidity sensor 30 is inverted and input to the AND circuit 22 described above.
In addition to the AND circuit 22, an AND circuit 32 that calculates the logical product of the detection output of the humidity sensor 30 and the output of the comparator 20 is provided. Further, the motor 13 and the power supply 25 are connected by the double switches 34A, 34B, 35A, 35B as shown in the figure, and the switching circuit 36 of the double switches 34A, 34B is connected to the AND circuit 22 and the double switch 35A, 35A. The switching circuit 37 of 35B is the AND circuit 32.
Connected to.

According to the second embodiment as described above, when the weather is fine and the inside of the housing 28 has a predetermined temperature, the AND circuit 2 is provided.
2 and 32 both do not satisfy the AND condition (Low signal),
The motor 13 is not activated. Also, the housing 28
When the inside temperature becomes equal to or higher than the predetermined temperature, the AND circuit 22 outputs the High signal as in the first embodiment, but the AND circuit 32 outputs the Low signal. Therefore, at this time, the switching circuit 36 causes the double switches 34A, 3A to operate.
Both 4B are turned on (input), the outside air is introduced into the inside by the rotation of the fan 12 as in the first embodiment, and the air circulated inside is discharged from the open / close valve 29 in the open state.

Furthermore, when the humidity sensor 30 detects a rainfall condition and the temperature sensor 15 detects a temperature higher than a predetermined temperature, that is, even though the outside temperature decreases due to rain, the inside of the housing 28 has a predetermined temperature. While maintaining the above, the AND circuit 22 outputs the Low signal, but the AND circuit 32 outputs the High signal. Therefore,
At this time, the other double switch 35A, 35B is turned on by the switching circuit 37, so that the power whose polarity is reversed is supplied from the power supply 25 to the motor 13.
As a result, the motor 13 is driven in reverse and the fan 12 is rotated in the reverse direction. As a result, the on-off valve 29 is closed and the air gently circulates in the housing 28 as shown by the arrow in the figure. Become.

In this inside air circulation, outside air slightly flows into the inside through the joints of the housing 28, small gaps, etc. However, this does not cause a trouble in the electric circuit. Further, in the second embodiment, the fan 12 is configured to be slightly movable inside the housing 28 and inclined downward, for example, when the inside air is circulated, and the direction of the fan 12 is changed from the position in FIG. The internal air circulation may be promoted by driving (electrically) and converting inward.

In the above embodiment, the rainfall detection sensor (16,
30) and the temperature sensor 15 are shown as an example, a television camera in which the temperature sensor 15 is not used, for example,
Even in the case where the fan is operated, the case where the fan is operated only for a predetermined time after the start of shooting, etc., the fan is controlled to be stopped when the rain condition is detected based on the rain detection sensor. It is possible.

[0023]

As described above, according to the first aspect of the invention, the rain detection sensor is provided, and the cooling fan is controlled to stop when the rain condition is detected. Is avoided, and it is possible to prevent obstruction to the electric circuit and fogging of the lens surface.

According to the second aspect of the present invention, the temperature sensor is provided, and the fan is operated when it is detected that the inside of the housing has reached a predetermined temperature or higher and the rain detection sensor does not detect the rain condition. Thus, there is an advantage that the fan is stopped not only when it is raining but also when the inside of the housing has a predetermined temperature or less, and the inside of the housing is efficiently cooled.

According to the third aspect of the present invention, when the predetermined temperature is detected by the temperature sensor and the rainfall state is detected by the rainfall detection sensor, the fan is controlled to be switched to the internal air circulation. Therefore, there is an advantage that the inside of the housing can be cooled when the temperature is lowered due to rainfall while preventing the intrusion of raindrops.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a fan control device for a television camera according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration inside a control unit of FIG.

FIG. 3 is a diagram showing a configuration of a fan control device for a television camera according to a second embodiment.

FIG. 4 is a circuit diagram showing a configuration inside a control unit of FIG.

[Explanation of symbols]

 10, 28 ... Housing, 12 ... Fan, 13 ... Motor, 15 ... Temperature sensor, 16 ... Raindrop sensor, 18, 31 ... Control part, 22, 32 ... AND circuit, 29 ... Open / close valve, 30 ... Humidity sensor.

Claims (3)

[Claims] 1. A television camera fan control device for driving and controlling a fan for taking in outside air into a housing of a television camera, wherein a rainfall detection sensor for detecting a rainfall state is provided, and when the rainfall detection sensor detects the rainfall state. A fan control device for a television camera, wherein the fan is controlled to be stopped. 2. A temperature sensor for detecting a temperature inside the housing of a television camera is provided, and the fan is operated when a predetermined temperature is detected by the temperature sensor and a rain condition is not detected by the rain detection sensor. The fan control device for a television camera according to claim 1, wherein the fan control device is configured as described above. 3. The first switch, wherein when the predetermined temperature is detected by the temperature sensor and the rainfall state is detected by the rainfall detection sensor, the fan is controlled so as to circulate inside air. Alternatively, the fan control device for the television camera according to claim 2.