JP2013098454A - Electronic apparatus and method for cooling electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic apparatus in which a change in pressure inside a casing can be suppressed and temperature control of a temperature elevation member can be performed accurately.SOLUTION: A casing 10 internally has liquid crystal elements 1R, 1B, 1G which are temperature elevation members. An intake fan 3 takes in air for cooling the temperature elevation members. An exhaust fan 5 exhausts air in the casing 10. A pressure sensor 20 detects a difference between the inside pressure of the casing 10 and outside pressure and outputs pressure data. A portion of a controller 21, a pressure/rotation speed setting table 22, a synchronizer 23, a clock generator 24, a PWM driver 25 and an adder 26 controls a rotation speed of the exhaust fan 5 in accordance with the pressure data and controls a degree for the exhaust fan 5 to exhaust air.

Description

  The present invention relates to an electronic device having an improved structure and method for cooling a temperature raising member and a method for cooling the electronic device.

  A liquid crystal projector, which is an example of an electronic device, includes a liquid crystal element that modulates liquid crystal according to a video signal. When the liquid crystal projector is operated, the temperature of the liquid crystal element rises due to heat generated by the drive circuit and irradiated light. A heating element that generates heat by itself or a member that rises in temperature by heat applied from the outside is collectively referred to as a temperature raising member. In the liquid crystal projector, in addition to the liquid crystal element, a power supply unit, a lamp, an electric circuit, and the like serve as a temperature raising member. Therefore, the liquid crystal projector includes a cooling fan for cooling a temperature increasing member such as a liquid crystal element. As described in Patent Document 1, there are cases where an intake fan and an exhaust fan are provided as cooling fans.

JP-A-11-84534

  When the electronic apparatus includes a plurality of cooling fans for cooling the temperature raising member as described above, the pressure inside the housing is likely to change due to the mutual influence of the plurality of cooling fans. When the pressure changes, the number of rotations of the cooling fan fluctuates and the air flow rate changes. Therefore, desired cooling characteristics cannot be obtained, and temperature control of the temperature raising member may not be performed accurately. As the intake fan, a centrifugal sirocco fan is often used. Since the sirocco fan is more susceptible to pressure changes than the axial flow fan, it is particularly required to accurately control the temperature of the temperature raising member.

  In order to meet such a demand, the present invention provides an electronic device and a method for cooling the electronic device that can suppress a change in pressure inside the housing and can accurately control the temperature of the temperature raising member. With the goal.

  In order to solve the above-described problems of the related art, the present invention is attached to a housing (10) having a temperature raising member (1R, 1B, 1G) inside and a suction port of the housing, and the temperature rise An intake fan (3, 3R, 3B, 3G) that takes in air for cooling the member, an exhaust fan (5) that is attached to an exhaust port of the housing and exhausts air in the housing, and the housing A pressure sensor (20) that detects a difference between the internal pressure and the external pressure of the gas and outputs pressure data indicating the difference, and a discharge control unit (21) that controls the degree to which the exhaust fan discharges air according to the pressure data. To 26).

  In the above electronic apparatus, it is preferable that the exhaust control unit is an exhaust fan rotational speed control unit that controls the rotational speed of the exhaust fan according to the pressure data.

  In the electronic apparatus, a temperature sensor (13G, 13B, 13R) that detects the temperature of the temperature raising member and outputs temperature data, and an intake fan rotation that controls the number of revolutions of the intake fan according to the temperature data It is preferable to include a number controller (11 to 15).

  In the above electronic device, when the casing has a plurality of temperature raising members (1R, 1B, 1G), a plurality of intake fans (3R, 3B, 3G) corresponding to the plurality of temperature raising members, And a temperature sensor (13G, 13B, 13R) for detecting the temperature of each of the plurality of temperature raising members and outputting the respective temperature data, wherein the intake fan rotation speed control unit is provided for each of the plurality of temperature raising members. It is preferable to individually control the rotational speeds of the plurality of intake fans according to the temperature data.

  In the above electronic device, the temperature raising member may be a liquid crystal element, and the electronic device may be a liquid crystal projector.

  In order to solve the above-described problems of the prior art, the present invention provides an intake fan (3, 3R, 3B) attached to an intake port of a housing (10) having a temperature raising member (1R, 1B, 1G) inside. , 3G) takes in air for cooling the temperature raising member, exhausts the air in the housing by an exhaust fan (5) attached to the exhaust port of the housing, and generates an internal pressure and an external pressure of the housing. The electronic device cooling method is characterized in that pressure data is generated by detecting the difference between the two, and the degree to which the exhaust fan discharges air is controlled according to the pressure data.

  In the electronic device cooling method, it is preferable to control the number of rotations of the exhaust fan according to the pressure data.

  In the electronic device cooling method, it is preferable that temperature data is generated by detecting the temperature of the temperature raising member, and the rotational speed of the intake fan is controlled according to the temperature data.

  In the electronic device cooling method, the housing includes a plurality of temperature raising members (1R, 1B, 1G), and a plurality of intake fans (3R, 3B, 3G) corresponding to the plurality of temperature raising members, respectively. Each of the plurality of temperature raising members is cooled by detecting the temperature of each of the plurality of temperature raising members to generate respective temperature data, and the plurality of intake airs according to the temperature data of each of the plurality of temperature raising members. It is preferable to individually control the rotation speed of the fan.

  According to the electronic device and the electronic device cooling method of the present invention, it is possible to suppress a change in pressure inside the housing, and to accurately control the temperature of the temperature raising member.

It is a block diagram which shows 1st Embodiment of the electronic device of this invention. It is a PQ characteristic diagram showing the relationship between the air volume and pressure of the sirocco fan used in each embodiment. It is a block diagram which shows 2nd Embodiment of the electronic device of this invention. It is a block diagram which shows 3rd Embodiment of the electronic device of this invention.

  Hereinafter, embodiments of an electronic device and a cooling method for an electronic device according to the present invention will be described with reference to the accompanying drawings. Each embodiment described later will be described by taking a liquid crystal projector as an example of the electronic apparatus. The electronic device is not limited to a liquid crystal projector, and may be any electronic device having a temperature raising member that requires cooling.

<First Embodiment>
In FIG. 1, liquid crystal elements 1 </ b> R, 1 </ b> B, and 1 </ b> G as examples of temperature raising members are attached at predetermined positions in the housing 10. The liquid crystal elements 1R, 1B, and 1G are modulation elements for modulating the three primary color video signals of red, blue, and green, respectively. Heat sinks 2R, 2B, and 2G for heat dissipation are attached to the liquid crystal elements 1R, 1B, and 1G, respectively. An intake fan 3 is attached to an intake port provided on the left side of the housing 10 in FIG. In the first embodiment, a sirocco fan is used as the intake fan 3. The hatched arrows indicate the flow of air taken into the housing 10.

  A duct 4 is connected to the intake fan 3. In the first embodiment, the air taken into the housing 10 by one intake fan 3 is led to the vicinity of the liquid crystal elements 1R, 1B, 1G (heat sinks 2R, 2B, 2G) by the duct 4, and the liquid crystal elements 1R, 1B, 1G are guided. (Heatsink 2R, 2B, 2G) is cooled. The duct 4 includes an opening 4or facing the heat sink 2R, an opening 4ob facing the heat sink 2B, and an opening 4og facing the heat sink 2G. Since the amount of heat generated varies depending on the liquid crystal elements 1R, 1B, and 1G, it is preferable to make the areas of the openings 4or, 4ob, and 4og different, for example, 1: 4: 5 in the order of the openings 4or, 4ob, and 4og.

  An exhaust fan 5 is attached to an exhaust port provided on the right side of the housing 10 in FIG. In the first embodiment, an axial flow fan is used as the exhaust fan 5. The hatched arrows indicate the flow of air discharged from the housing 10.

  FIG. 2 shows the PQ characteristic indicating the relationship between the air volume and pressure (static pressure) of the sirocco fan. As can be seen from FIG. 2, the sirocco fan has a characteristic that the air volume increases as the static pressure decreases, and the air volume decreases as the static pressure increases. When the static pressure is maximum, the air volume is 0 in the fully closed state, and when the air volume is maximum, there is no pressure free air. If the pressure in the housing 10 changes, the air volume of the intake air from the intake fan 3 changes.

  Although not particularly illustrated, the casing 10 has a heating element such as a power supply unit and a lamp in addition to the liquid crystal elements 1R, 1B, and 1G as temperature raising members. There are also cooling fans. This cooling fan tends to change the pressure in the housing 10 and affects the amount of air sucked by the intake fan 3.

  Therefore, in the first embodiment, the rotational speed of the intake fan 3 and the rotational speed of the exhaust fan 5 are individually managed and individually controlled. The rotation pulse Prt3 output from the intake fan 3 is input to the synchronization unit 13. A reference clock (reference pulse) generated by the clock generation unit 14 is input to the synchronization unit 13. The PWM drive unit 15 supplies a drive pulse having a predetermined pulse width to the intake fan 3. The intake fan 3 rotates at a rotation speed corresponding to the pulse width of the drive pulse. The synchronization unit 13 controls the PWM drive unit 15 so that the rotation pulse Prt3 matches the reference clock.

  The intake fan 3 is controlled so that the rotation pulse Prt3 is constant by the first loop of the intake fan 3 → the synchronization unit 13 → the PWM drive unit 15 → the intake fan 3. In this first loop, the rotational speed of the intake fan 3 is controlled in real time.

  Temperature sensors 13G, 13B, and 13R are mounted on the liquid crystal elements 1R, 1B, and 1G, respectively. The controller 11 receives at least temperature data from the temperature sensor 13B mounted on the liquid crystal element 1B. As indicated by a broken line, temperature data from the temperature sensors 13G and 13R may also be input to the control unit 11.

  In the temperature / rotation speed setting table 12, the rotation speed of the intake fan 3 is set with respect to the temperature of the liquid crystal element 1B (1R, 1G). The control unit 11 controls the synchronization unit 13 so as to set the rotation speed of the intake fan 3 according to the temperature data from the temperature sensor 13B. If the temperature of the liquid crystal element 1B rises, control is performed to increase the rotational speed of the intake fan 3. In the intake fan 3, the rotation pulse Prt3 is controlled according to the temperature of the liquid crystal element 1B by the second loop of the liquid crystal element 1B → the control unit 11 → the synchronization unit 13 → the PWM drive unit 15 → the intake fan 3. In the second loop, for example, the control signal output from the control unit 11 is updated every 30 seconds.

  The control signal output from the control unit 11 to the synchronization unit 13 is the number of clocks for designating the number of rotations.

  In FIG. 1, a control unit 11, a temperature / rotation speed setting table 12, a synchronization unit 13, a clock generation unit 14, and a PWM drive unit 15 are inhaled according to temperature data from a temperature sensor 13B (13R, 13G). An intake fan rotation speed control unit that controls the rotation speed of the fan 3 is provided.

  The rotation pulse Prt5 output from the exhaust fan 5 is input to the synchronization unit 23. A reference clock (reference pulse) generated by the clock generation unit 24 is input to the synchronization unit 23. The PWM drive unit 25 supplies a drive pulse having a predetermined pulse width to the exhaust fan 5. The exhaust fan 5 rotates at a rotation speed corresponding to the pulse width of the drive pulse. The synchronization unit 23 controls the PWM drive unit 25 so that the rotation pulse Prt5 matches the reference clock.

  The exhaust fan 5 is controlled so that the rotation pulse Prt5 becomes constant by the third loop of the exhaust fan 5 → the synchronization unit 23 → the PWM drive unit 25 → the exhaust fan 5. In the third loop, the rotational speed of the exhaust fan 5 is controlled in real time.

  A pressure sensor 20 that detects a difference between an internal pressure (internal pressure) and an external pressure (external pressure) of the housing 10 is attached to the housing 10. Pressure data indicating the difference between the internal pressure and the external pressure from the pressure sensor 20 is input to the control unit 21. In the pressure / rotation speed setting table 22, the rotation speed of the exhaust fan 5 is set for the pressure data from the pressure sensor 20. The controller 21 refers to the pressure / rotation speed setting table 22 and sets a target rotation speed for the synchronization section 23 so as to set the rotation speed of the exhaust fan 5 according to the pressure data from the pressure sensor 20. .

  The exhaust fan 5 has a rotation pulse Prt5 corresponding to the pressure difference between the inside and the outside of the housing 10 by the fourth loop of the pressure sensor 20 → the control unit 21 → the synchronization unit 23 → the PWM drive unit 25 → the exhaust fan 5. Controlled. In the fourth loop, for example, the control signal output from the control unit 21 is updated every 30 seconds. The control signal output from the control unit 21 to the synchronization unit 23 is the number of clocks for designating the number of rotations.

  When the internal pressure of the housing 10 is Pain and the external pressure is Paout, the internal pressure Pain is slightly higher than the external pressure Paout in order for the air taken into the housing 10 by the intake fan 3 to be efficiently discharged by the exhaust fan 5. The degree is good. That is, a positive pressure within a predetermined range is good in the housing 10. Therefore, when the internal pressure Pain is higher than the external pressure Paout by a predetermined value or more, the rotation speed of the exhaust fan 5 is increased by the control by the fourth loop, and the internal pressure Pain is equal to the external pressure Paout or the internal pressure Pain is higher than the external pressure Paout. If it is low, the rotational speed of the exhaust fan 5 is reduced by the control by the fourth loop.

  In the first embodiment, the specific configuration of the first to fourth loops is not limited to the configuration shown in FIG. 1, and the specific configuration can be changed as appropriate.

  In FIG. 1, a control unit 21, a pressure / rotation speed setting table 22, a synchronization unit 23, a clock generation unit 24, and a PWM drive unit 25 are arranged so that the exhaust fan 5 generates air according to pressure data from the pressure sensor 20. It is a discharge control unit that controls the degree of discharge. In FIG. 1, as a preferable configuration, the exhaust control unit is an exhaust fan rotational speed control unit that controls the rotational speed of the exhaust fan 5 according to pressure data.

Second Embodiment
3, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted as appropriate. In the second embodiment shown in FIG. 3, an intake fan 3R is provided for the liquid crystal element 1R (heat sink 2R), an intake fan 3B is provided for the liquid crystal element 1B (heat sink 2B), and the liquid crystal element 1G (heat sink 2). 2G) is provided with an intake fan 3G. The intake fans 3R, 3B, 3G are sirocco fans.

  The controller 11 receives temperature data from temperature sensors 13G, 13B, and 13R attached to the liquid crystal elements 1R, 1B, and 1G, respectively. The controller 11 receives temperature data from the temperature sensors 13G, 13B, and 13R, and the intake fans 3R, 3B, and 3G are individually provided for the liquid crystal elements 1R, 1B, and 1G. The intake fans 3R, 3B, 3G can be individually controlled by the loop. Therefore, the liquid crystal elements 1R, 1B, and 1G are controlled to an optimum state according to individual temperatures.

  In FIG. 3, the control unit 21 in FIG. 1 is omitted, and both the synchronization unit 13 and the synchronization unit 23 are controlled by one control unit 11. Pressure data from the pressure sensor 20 is input to the control unit 11. The controller 11 refers to the pressure / rotation speed setting table 22 and sets a target rotation speed for the synchronization section 23 so as to set the rotation speed of the exhaust fan 5 according to the pressure data from the pressure sensor 20. To do.

  3, similarly to FIG. 1, the two control units 11 and 21 may be provided, and the synchronization unit 13 and the synchronization unit 23 may be individually controlled. The specific configurations of the first to fourth loops and the specific configurations of the intake fan rotation speed control unit and the exhaust control unit (exhaust fan rotation speed control unit) can be changed as appropriate.

<Third Embodiment>
4, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted as appropriate. In the third embodiment shown in FIG. 4, the control for the exhaust fan 5 is different from those in FIGS. Pressure data from the pressure sensor 20 is input to the control unit 26. In the pressure / shutter setting table 27, the position (the degree of opening / closing) of the shutter 30 with respect to the exhaust fan 5 provided inside the housing 10 is set for the pressure data from the pressure sensor 20.

  The control unit 26 refers to the pressure / shutter setting table 27 and inputs the position data of the shutter 30 corresponding to the pressure data from the pressure sensor 20 to the shutter control unit 28. The shutter control unit 28 drives the drive unit 29 according to the input position data to move the shutter 30 to an appropriate position. The position of the shutter 30 is controlled by the drive unit 29 as indicated by a broken-line double arrow. If the shutter 30 moves in the direction to block the exhaust fan 5 (upward in FIG. 4), the amount of exhaust by the exhaust fan 5 decreases, and the shutter 30 does not block the exhaust fan 5 (downward in FIG. 4). If it moves, the amount of exhaust by the exhaust fan 5 increases.

  In FIG. 4, the control unit 26, the pressure / shutter setting table 27, the shutter control unit 28, the drive unit 29, and the shutter 30 indicate the extent to which the exhaust fan 5 discharges air according to the pressure data from the pressure sensor 20. It becomes the discharge control part to control. The exhaust control unit in FIG. 4 is configured to control the degree to which the exhaust fan 5 exhausts air by keeping the rotational speed of the exhaust fan 5 constant and varying the degree to which the exhaust fan 5 is blocked by the shutter 30.

  According to each embodiment described above, since the exhaust control unit that controls the degree to which the exhaust fan 5 discharges air according to the pressure data that is the difference between the internal pressure and the external pressure of the housing 10, Can be maintained at a moderate positive pressure. Therefore, a change in pressure inside the housing 10 can be suppressed, and the temperature control of the temperature raising member can be accurately performed. As a preferred configuration, each embodiment includes an intake fan rotation speed control unit that controls the rotation speed of the intake fans 3, 3R, 3B, and 3G in accordance with the temperature of the temperature increase member, so that the temperature control of the temperature increase member is further performed. It is possible to perform accurately.

  According to each embodiment, since the temperature of the temperature raising member can be accurately controlled, it is possible to suppress noise without rotating the intake fans 3, 3R, 3B, 3G and the exhaust fan 5 more than necessary. As a result, there is a secondary effect that power consumption can be reduced.

  The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the present invention. As described above, each embodiment uses a liquid crystal projector as an example of the electronic apparatus, but is not limited thereto. Further, the temperature raising member to be cooled is not limited to the liquid crystal element.

1R, 1B, 1G Liquid crystal element (temperature raising member)
2R, 2B, 2G Heat sink 3, 3R, 3B, 3G Intake fan 4 Duct 5 Exhaust fan 10 Housing 13G, 13B, 13R Temperature sensor 11, 21, 26 Control unit 12 Temperature / rotation speed setting table 13, 23 Synchronization unit 14, 24 Clock generation unit 15, 25 PWM drive unit 20 Pressure sensor 22 Pressure / rotation speed setting table 27 Pressure / shutter setting table 28 Shutter control unit 29 Drive unit 30 Shutter

Claims (9)

A housing having a temperature raising member therein;
An intake fan attached to the suction port of the housing and taking in air for cooling the temperature raising member;
An exhaust fan attached to an exhaust port of the housing and exhausting air in the housing;
A pressure sensor that detects a difference between an internal pressure and an external pressure of the housing and outputs pressure data indicating the difference;
A discharge control unit that controls the degree to which the exhaust fan discharges air according to the pressure data;
An electronic device comprising:   The electronic apparatus according to claim 1, wherein the exhaust control unit is an exhaust fan rotational speed control unit that controls the rotational speed of the exhaust fan according to the pressure data. A temperature sensor that detects the temperature of the temperature raising member and outputs temperature data;
An intake fan rotation speed control unit that controls the rotation speed of the intake fan according to the temperature data;
The electronic apparatus according to claim 1, further comprising: The housing has a plurality of temperature raising members,
A plurality of intake fans corresponding to each of the plurality of temperature raising members;
A temperature sensor that detects the temperature of each of the plurality of temperature raising members and outputs respective temperature data; and
The electronic apparatus according to claim 3, wherein the intake fan rotation speed control unit individually controls the rotation speeds of the plurality of intake fans according to temperature data of the plurality of temperature raising members.   The electronic apparatus according to claim 1, wherein the temperature raising member is a liquid crystal element, and the electronic apparatus is a liquid crystal projector. Intake air for cooling the temperature raising member by an intake fan attached to the suction port of the housing having the temperature raising member inside,
Exhaust air in the housing by an exhaust fan attached to the exhaust port of the housing,
Detecting the difference between the internal pressure and the external pressure of the housing to generate pressure data;
A method for cooling an electronic device, wherein the degree to which the exhaust fan discharges air is controlled according to the pressure data.   The method for cooling an electronic device according to claim 6, wherein the number of revolutions of the exhaust fan is controlled according to the pressure data. Detecting the temperature of the temperature raising member to generate temperature data;
The method for cooling an electronic device according to claim 6 or 7, wherein the number of revolutions of the intake fan is controlled in accordance with the temperature data. The housing has a plurality of temperature raising members,
Cooling each of the plurality of temperature raising members by a plurality of intake fans corresponding to each of the plurality of temperature raising members;
Detecting the temperature of each of the plurality of temperature raising members to generate respective temperature data;
The method for cooling an electronic device according to claim 8, wherein the number of rotations of the plurality of intake fans is individually controlled according to temperature data of each of the plurality of temperature raising members.

Images