JP2005050952A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus in which the fan noise can effectively be reduced. <P>SOLUTION: The electronic apparatus is provided with a heating element (190) arranged inside a cabinet, a fan (130) cooling inside the cabinet heated by the heating element, a measuring means (140) for measuring the sound generated by the fan, speakers (150) disposed by leaving prescribed intervals from the fan, and a control means (180) for controlling the sound outputted from the speakers so as to be in opposite phase to the sound generated by the fans in accordance with a measuring result of the measuring means, the prescribed intervals and a position of a user. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic device having a heating element such as a CPU (Central Processing Unit) inside the casing, and more particularly to an electronic device having a fan for cooling the heated casing.
[0002]
[Prior art]
An electronic device such as a notebook personal computer (hereinafter referred to as a notebook PC) has a heating element such as a CPU mounted inside the casing, so that the temperature inside the casing is considerably high. For this reason, many fans have a cooling fan mounted inside the housing.
[0003]
In such an electronic device, there is a problem that the sound generated by the rotation of the fan becomes noise.
For this reason, the conventional electronic equipment uses an active noise cancellation method (hereinafter referred to as ANC method) in which noise is eliminated by hitting a sound having an opposite phase and the same amplitude with respect to the noise. The duct is provided to radiate the fan noise toward the outside of the housing as a monopole sound having the same phase in the radiation plane. Further, a microphone (hereinafter simply referred to as a microphone) provided in the vicinity of the fan receives fan noise, and a microphone provided in the vicinity of the fan has a sound having an opposite phase and the same amplitude as the fan noise (hereinafter referred to as erasing sound). Are radiated toward the fan noise, and the fan noise is three-dimensionally erased by the erasing sound (see, for example, Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-268872 (pages 2 to 5, FIGS. 1 and 2)
[0005]
[Problems to be solved by the invention]
However, since it is necessary to provide a duct and a speaker for reducing fan noise near the fan, there is a problem that the thickness of the housing increases.
An object of the present invention is to provide an electronic device that can effectively reduce fan noise.
[0006]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a heating element provided in a casing, a fan for cooling the casing heated by the heating element, a measuring means for measuring sound generated from the fan, the fan and a predetermined The sound output from the speaker has an opposite phase to the sound generated from the fan according to the measurement result of the measurement means, the measurement result of the measurement means, the predetermined interval and the position of the user. It is an electronic device provided with the control means to control.
[0007]
According to a second aspect of the present invention, in the electronic device according to the first aspect, the sound output from the speaker is controlled to have the same amplitude as the sound generated from the fan.
A third invention is the electronic device according to the first invention, wherein the speaker is provided in a place closer to the user than the measuring means.
According to a fourth aspect of the present invention, in the electronic device according to the first aspect, the sound output from the speaker is controlled in consideration of the delay of the sound generated from the fan by the predetermined interval. .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an appearance of a notebook PC according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram inside a casing 120 of the notebook PC according to the embodiment. The notebook PC includes a display 110 and a casing 120 on which a keyboard 160 and the like are mounted. Since the housing 120 includes a heat generating portion 190 such as a CPU, a fan 130 for cooling the inside of the housing is provided. The microphone 140 is built in the housing 120 so as to be provided near the lateral side of the fan 130 in order to measure the noise of the fan 130. Further, the speakers 150a and 150b are built in a position away from the fan 130 by a predetermined interval.
[0009]
FIG. 3 is a diagram for explaining the positional relationship between the notebook PC and the user according to the present embodiment. Since the user 170 faces the display 110 and operates a keyboard or the like, the user 170 is usually used away from the housing 120 by a certain interval. Therefore, not only the distance Y between the fan 130 and the speaker 150 is determined by design, but also the distance X between the fan 130 and the user 170's ear is approximately determined, for example, about 50 cm.
[0010]
FIG. 4 is a diagram for explaining the principle of noise cancellation according to the present embodiment, and FIG. 5 is a flowchart of noise cancellation according to the present embodiment. The noise generated by the fan 130 reverberates throughout the periphery and reaches the ears of the user 170 that is a distance X away. The microphone 140 receives the noise of the fan 130 (S510), converts it into an electrical signal, and outputs it to the control unit 180 such as a processor. The control unit 180 may be an analog circuit or a microcontroller. In FIG. 4, the microphone 140 is drawn on the fan 130, but this is for convenience of explanation, and the thickness of the housing 120 is not increased by installing the microphone 140 near the side of the fan 130. Can be.
[0011]
The control unit 180 takes into account the sound delay due to the distance Y between the fan 130 and the speaker 150 in order to reduce the noise generated by the fan 130 from being heard by the user 170, and has an opposite phase to the sound of the microphone 140. An electric signal for generating the sound is generated (S520). The speaker 150 receives this electric signal and outputs a sound with an opposite phase (S530).
[0012]
In this way, the sound from the speaker 150 cancels out the sound from the fan 130 at the position of the user 170 separated by a distance Z, and noise is reduced. Thus, in this embodiment, unlike the conventional fan noise reduction technology that reduces the entire fan noise at the duct outlet, the sound generated from the fan is a distance Y from the sound output from the speaker. Considering the delay, the noise at the user's position is reduced. Accordingly, since it is not necessary to reduce the entire fan noise, a dedicated duct for noise reduction is unnecessary in the vicinity of the fan. Further, there is no need to provide a dedicated speaker for noise reduction, and a speaker that is mounted as a standard in the notebook PC housing can be used. Therefore, fan noise at the user's position can be reduced without increasing the thickness of the housing.
[0013]
Note that the sound from the speaker 150 has an opposite phase to the sound of the microphone 140, but noise can be reduced more effectively if the sound has the same amplitude.
If the distance Y between the microphone 140 and the speaker 150 is long, there is a margin in the processing of the control unit 180, so that further filter operations are possible.
The above-described embodiment is a preferred specific example of the present invention, and thus various technically preferable limitations are given. However, the embodiments are appropriately combined and changed within a range not departing from the gist of the present invention. It goes without saying that it can be done.
[0014]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an electronic device that can effectively reduce fan noise.
[Brief description of the drawings]
FIG. 1 is an external view of a notebook PC according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram inside a casing 120 of the notebook PC according to the present embodiment.
FIG. 3 is a view for explaining the positional relationship between the notebook PC and the user according to the embodiment.
FIG. 4 is a view for explaining the principle of noise cancellation according to the present embodiment.
FIG. 5 is a flowchart of noise cancellation according to the present embodiment.
[Explanation of symbols]
110 Display 120 Case 130 Fan 140 Microphone 150a, b Speaker 160 Keyboard 170 User 180 Control unit 190 Heat generation part (CPU etc.)

Claims (4)

A heating element provided inside the housing;
A fan for cooling the inside of the housing heated by the heating element;
Measuring means for measuring the sound generated from the fan;
A speaker provided at a predetermined interval from the fan;
An electronic device comprising: control means for controlling the sound output from the speaker to have an opposite phase to the sound generated from the fan according to the measurement result of the measuring means, the predetermined interval and the position of the user . 2. The electronic apparatus according to claim 1, wherein a sound output from the speaker is controlled to have the same amplitude as a sound generated from the fan. The electronic apparatus according to claim 1, wherein the speaker is provided at a place closer to the user than the measurement unit. 2. The electronic apparatus according to claim 1, wherein the sound output from the speaker is controlled in consideration of a delay of the sound generated from the fan by the predetermined interval.

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