JPH0573072A - Silencer device - Google Patents

Abstract

PURPOSE:To reduce the noise of a motor driving fan for heat radiation by the interference effect in a television receiver which has a speaker. CONSTITUTION:This device is equipped with the motor driving fan 3 for heat radiation which is installed in part of the television receiver, a disk 10 which is fitted on the shaft of the motor driving fan 3 and rotates corresponding to the rotation of the shaft, a sensor 12 which detects the hole 11 of the disk 10, a sound eliminating speaker 4 which is provided on the flank of the motor driving fan 3, and a control means 14 which actually generates a noise by the motor driving fan 3 previously and generates its phase inverted sound from the speaker for the noise generated by the motor driving fan 3 according to the detection signal of the sensor 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise reduction device for a motor drive fan used for heat dissipation of a television receiver.

[0002]

2. Description of the Related Art A conventional silencer will be described below. FIG. 1 is a block diagram of a conventional noise reduction device. 1 is a television receiver, 2 is a first speaker, 3 is a motor drive fan, 4 is a second speaker, 5 is a first microphone,
6 is a second microphone, 7 is a phase inversion unit, 8 is a phase control unit, and 9 is an amplification unit.

In recent years, the television receiver 1 has been highly functionalized, power consumption has increased, and heat dissipation has become a major issue. Motor drive fan 3 for heat dissipation in the television receiver 1
Is installed, the first microphone 5 is arranged in the vicinity of the motor drive fan 3, and the second speaker 2,
The second microphone 6 is installed.

Further, the noise signal of the motor drive fan 3 received by the first microphone 5 passes through the phase inversion unit 7 which inverts the phase, and the noise signal received by the second microphone 6 causes the phase-inverted signal to be phased. The amplifier 9 has a function of amplifying the signal after the phase control through the controlled phase controller 8 and changing the amplification degree by the noise signal of the second microphone 6.

The signal that has passed through the amplification section is output from the second speaker 4 so that the noise wave of the motor drive fan 3 is reduced by interference (silence).

[0006]

However, in the above-mentioned conventional configuration, the sound of the television receiver from the first speaker 2 is input from the first and second microphones 5 and 6, and the sound is particularly loud. Sometimes, there is a problem that the effect of noise reduction decreases. That is, when the noise generated from the motor drive fan 3 is fed back and the noise is always made to be the phase-inverted sound, the noise from the first speaker 2 originally provided in the television receiver 1 can be distinguished. It is difficult, and it is considered that the silent effect cannot be expected so much.

The present invention has been made in view of the above problems of the conventional television receiver, and an object of the present invention is to provide a silencer which is not affected by the influence of television sound or the external sound to the television receiver.

[0008]

According to the present invention, there is provided a motor drive fan for heat radiation installed in a part of a television receiver having a first speaker for outputting television sound, and a motor drive fan mounted on the shaft of the motor drive fan. A predetermined member that rotates according to the rotation of the shaft, a sensor that detects the rotational state of the predetermined member, a second speaker that is provided at a predetermined position with respect to the motor drive fan, and a sensor that detects the second member. In response to the generated signal, in response to the noise generated from the motor drive fan, the second speaker actually generates noise in the motor drive fan in advance and generates a sound whose phase is inverted. And a control means for controlling.

[0009]

According to the present invention, the motor driving fan is actually rotated in advance, the noise generated at that time is phase-inverted, and the phase-inverted noise signal is used to detect the rotation state of a predetermined member attached to the motor-driving fan. It is stored together with the signal detected by the sensor, and during actual use, the control means uses the detection signal from the sensor to detect the noise generated from the motor drive fan from the second speaker in advance. I want to prepare so that the reverse voice is output and the noise is reduced.
Therefore, it is not necessary to feed back the noise from the motor driving fan, and the influence of the TV sound or the external sound is not influenced, so that the noise of the motor driving fan can be further reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an embodiment of a noise reduction device according to the present invention. In the figure, the second speaker 4 is installed on the side surface of the cylindrical heat dissipation hole 13 provided in the television receiver 1, and the motor drive fan 3 is installed on the bottom surface of the cylindrical heat dissipation hole 13. A disk 10 having a hole 11 is provided on the drive shaft of the motor driving fan 3, and a photo sensor 12 is installed so as to sandwich the disk 10. When the noise generated from the motor drive fan 3 reaches a steady state, its size, frequency, and timing are uniquely determined by the shape, number of blades, rotational speed, position, and the like. It is possible to measure these values concerning the noise generated from the motor drive fan 3 in advance and obtain the sound with the optimum silencing effect. In the present embodiment, instead of the conventional noise reduction by feedback, the disk 10 having the hole 11 in the drive shaft of the motor drive fan 3 is used to detect the reference position by the photo sensor 12, and from this reference position ,
When the angular phase difference of how much in advance disc 10, the noise from the motor-driven fan 3 by measuring whether occurring, it is possible to quieter by the feed-forward.

That is, the noise generated from the rotating motor drive fan 3 exhibits a predetermined change with a cycle of one rotation after the steady state. Therefore, paying attention to how much noise occurs from the reference position and how much noise is generated, it is a characteristic unique to the equipment, and a microcomputer is built in the control means to have a memory function, The motor driving fan 3 is actually rotated to generate noise, an inverted phase signal thereof is generated, and a timing signal for outputting a sound whose phase is inverted is transmitted from the outside to the control unit so that the noise level is below a certain level. Adjust so that the value can be memorized. By doing this, when using,
The motor driving fan 3 starts rotating, and a timer or the like is used to check whether or not a steady state has been reached. When the steady state is reached, the control means automatically outputs a phase-inverted sound from the second speaker 4. By generating and weakening by the sound interference effect, the motor drive fan 3 can be made quiet. That is, by detecting the hole 11 of the disk 10 by the photo sensor 12, it is possible to detect the phase angle of the axis of the fan (how much it rotates during one rotation). Then, the control means 14 causes the second speaker 4 to generate a phase inversion noise signal stored in advance in synchronization with the detected phase angle. As a result, the noise of the motor drive fan 3 can be further reduced since it is not affected by the TV sound or the external sound.

Further, in the front projection type liquid crystal display device, it is possible to reduce the noise of the motor drive fan for forcedly cooling the lamp which is the light source. When forced air cooling by a large number of motor-driven fans is required as in a high-definition TV, it is possible to install the noise reduction device independently without affecting each other.

The predetermined member of the present invention is a disk provided with holes in the above embodiment, but the present invention is not limited to this, and it may be another means such as a magnetic label attached to the shaft of a motor driving fan. It may be. In short, the sensor only needs to be able to detect the rotation state of the motor driven fan.

Further, the sensor is not limited to the photo sensor, and various sensors can be used corresponding to a predetermined member such as a magnetic sensor.

The voice signal stored in advance may be the generated noise signal itself. In that case, the control means generates a sound while inverting the phase of the noise signal during actual use. It is a thing.

[0017]

As described above, since the noise reduction device according to the present invention is not affected by the influence of TV sound or the external sound, the noise of the motor driving fan is further reduced, and the power consumption accompanying the increase of IC is increased. With respect to heat generation due to increase, temperature can be guaranteed and product reliability is improved,
It is very useful for adding additional functions to the product.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a noise reduction device according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a conventional noise reduction device.

[Explanation of symbols]

 1 TV receiver 2 1st speaker 3 Motor drive fan 4 2nd speaker 5 1st microphone 6 2nd microphone 7 Phase inversion part 8 Phase control part 9 Amplification part 10 Disc 11 Hole 12 Photosensor 13 Cylinder normal heat radiation Hole 14 control means

Claims (2)

[Claims] 1. A motor drive fan for heat radiation installed in a part of a television receiver having a first speaker for outputting a television sound, and a motor drive fan attached to a shaft of the motor drive fan. A predetermined member that rotates in a predetermined manner, a sensor that detects a rotation state of the predetermined member, a second speaker that is provided at a predetermined position with respect to the motor driving fan, and the motor that responds to a signal detected by the sensor. Control means for generating noise from the second speaker, which is actually generated by the motor driving fan in advance, in response to the noise generated from the driving fan, and whose phase is inverted. Quiet device characterized by. 2. A heat-dissipating motor-driving fan installed in a part of a television receiver having a first speaker for outputting television sound, and a shaft of the motor-driving fan, which is attached according to rotation of the shaft. A predetermined member that rotates in a predetermined manner, a sensor that detects a rotation state of the predetermined member, a second speaker that is provided at a predetermined position with respect to the motor driving fan, and the motor that responds to a signal detected by the sensor. In response to the noise generated from the driving fan, the second speaker actually generates noise in the motor driving fan in advance, and a control means for generating the stored noise while inverting the phase. A silencer characterized by being provided.