JP6816496B2 - Electronics - Google Patents

Description

The present invention relates to electronic devices.

In recent years, in electronic devices, a small and highly efficient loop type heat pipe has been used as a cooling means for suppressing a temperature rise due to heat from a heat generating portion.

Generally, in a loop type heat pipe, as shown in FIG. 7, an evaporation unit 100 that receives heat from the outside and evaporates the working fluid from the liquid phase to the gas phase, and a heat radiation to the outside to dissipate the working fluid from the gas phase to the liquid phase. A condensing unit 200 for condensing into a phase, a steam pipe 300 for flowing the working fluid of the gas phase from the evaporating part 100 to the condensing part 200, and a liquid pipe 400 for flowing the working fluid for the liquid phase from the condensing part 200 to the evaporating part 100. (See Patent Document 1 and Patent Document 2).

A wick 500 made of a porous material is housed inside the evaporation unit 100, and the working fluid of the liquid phase sent from the liquid tube 400 permeates the fine pores of the wick 500 by capillary action and wicks. Exudes to the outer surface of 500. At this time, the heat from the heat generating unit (cooling target) in contact with the evaporation unit 100 is transferred to the wick 500 through the housing of the evaporation unit 100, and the working fluid evaporates due to the heat and changes to the gas phase. The working fluid changed to the gas phase moves to the condensing portion 200 through the steam pipe 300. In the condensing unit 200, the heat of the working fluid is released to the outside, so that the temperature of the working fluid is lowered and the phase changes to the liquid phase. Then, the working fluid changed to the liquid phase moves to the evaporation unit 100 through the liquid pipe 400 and permeates into the wick 500 again. In this way, in the loop type heat pipe, the cooling target is efficiently cooled by utilizing the phase change of the working fluid, circulating the working fluid, and transferring the heat absorbed by the evaporation part to the condensing part. Can be done.

By the way, in order for the loop type heat pipe to exhibit cooling performance efficiently, the working fluid of the gas phase is filled from the outer space of the wick to the steam pipe and the middle part of the condensing part, and from the middle part of the condensing part. It is desirable that the working fluid of the liquid phase is filled up to the liquid pipe and the inner space of the wick, and a gas-liquid interface is formed near the outer surface of the wick.

However, depending on the posture of the electronic device that is stopped or on standby, the distribution of the gas phase and the liquid phase of the working fluid in the loop type heat pipe may not be in the desired state as described above due to the influence of gravity or the like.

For example, if the electronic device is left for a long time in a posture in which the evaporating part is located above the condensing part during stop or standby, the working fluid of the liquid phase also flows into the vapor pipe, so that the evaporating part is inside the evaporating part. The liquid level of the working fluid of the liquid phase may drop, and the working fluid of the liquid phase may not penetrate to the upper part of the wick and become dry. In such a case, the amount of change of the working fluid from the liquid phase to the gas phase in the wick is reduced, and a part of the working fluid of the gas phase flows back from the dry region of the wick to the liquid pipe side, which is desirable. It becomes impossible to demonstrate the cooling performance of.

After that, the working fluid of the liquid phase of the steam pipe is pushed out to the working fluid of the gas phase by the heat from the heat generating part, so that the liquid level of the working fluid of the liquid phase in the evaporating part rises and the working fluid of the liquid phase spreads over the entire wick. However, when the cooling performance deteriorates, if the temperature of the heat generating portion exceeds the allowable temperature upper limit value, there is a risk of failure. In addition, if a loop type heat pipe with sufficient performance is selected in anticipation of a decrease in cooling performance due to the attitude of such electronic equipment, there are new problems such as increased cost and larger size. Occurs in.

In order to solve the above problems, the present invention comprises a heat generating portion, an evaporating portion that absorbs heat from the generating portion and evaporates the working fluid from the liquid phase to the gas phase, and a gas phase derived from the evaporating portion. An electronic device having a condensing portion for condensing the working fluid into the liquid phase and a loop type heat pipe for returning the working fluid of the condensed liquid phase to the evaporating portion, wherein the posture of the electronic device main body is changed. It is equipped with a posture detecting means for detecting, and when operating from a stopped state or a standby state, the heat generated by the heat generating portion is higher than that during normal operation before normal operation is performed based on the posture detected by the posture detecting means. It is characterized in that it is determined whether or not to perform a low heat generation operation that operates so that the amount is small.

According to the present invention, by detecting the posture of the main body of the electronic device, it is possible to determine the state of deterioration of the cooling performance of the loop type heat pipe due to the posture. Then, if the loop type heat pipe is in a posture where it is assumed that the original cooling performance cannot be exhibited, the temperature of the heat generating part is set to the allowable upper limit value by performing low heat generation operation before performing normal operation. It can be prevented from exceeding. On the other hand, if the loop type heat pipe is in a posture that is expected to be able to exhibit its original cooling performance, the user is functionally or performance-impaired by performing normal operation without performing low heat generation operation. Electronic devices can be used without the necessary restrictions. Further, in this way, by reducing the amount of heat generated by the heat generating portion of the electronic device according to the state in which the cooling performance of the loop type heat pipe is deteriorated, the electronic device can be used without mounting the loop type heat pipe having a sufficient performance. The temperature of the equipment can be maintained within the permissible range, which is advantageous for cost reduction and miniaturization.

It is a figure which shows an example of a loop type heat pipe. It is sectional drawing of the evaporation part in a loop type heat pipe. It is a schematic block diagram which shows one Embodiment of the electronic device which concerns on this invention. It is a figure which shows the control flow of the electronic device which concerns on this embodiment. It is a figure which shows the relationship between the calorific value of the heat generating part and the temperature rise after the start of operation. It is a figure which shows the other control flow. It is a figure which shows the structure of a general loop type heat pipe.

Hereinafter, the present invention will be described with reference to the accompanying drawings. In each drawing for explaining the present invention, components such as members and components having the same function or shape will be described once by giving the same reference numerals as much as possible. Omit.

First, a loop type heat pipe mounted on an electronic device will be described.

FIG. 1 is a diagram showing an example of a loop type heat pipe.
In the loop type heat pipe 1 shown in FIG. 1, a working fluid is sealed inside, and the working fluid is absorbed from the heat generating part to evaporate the working fluid from the liquid phase to the vapor phase, and the evaporating part 2 The condensing unit 3 that condenses the guided working fluid of the gas phase into the liquid phase, the vapor pipe 4 that circulates the working fluid of the gas phase from the evaporating unit 2 to the condensing unit 3, and the liquid from the condensing unit 3 to the evaporating unit 2. A liquid pipe 5 for passing a phase working fluid is provided. As the working fluid, a condensable fluid such as water, alcohol, acetone, or CFC substitute is used.

The evaporation unit 2 is a cylindrical member formed of a metal having good thermal conductivity such as copper or a copper alloy, and has a heat receiving unit 7 in which the wick 6 is housed and a reservoir for storing the working fluid of the liquid phase. It is composed of a part 8. One end of the steam pipe 4 is connected to the heat receiving portion 7, and one end of the liquid pipe 5 is connected to the reservoir portion 8. Further, the other ends of the steam pipe 4 and the liquid pipe 5 are connected to the condensing part 3. The condensing portion 3 has a plurality of flat tubes 9 through which the working fluid passes, and a large number of fins 10 provided outside each flat tube 9. Each flat pipe 9 is connected to each other at both ends, a vapor pipe 4 is connected to one end of the connection, and a liquid pipe 5 is connected to the other end of the connection.

The wick 6 is a hollow member made of a porous material such as metal, resin, or ceramic, and the steam pipe 4 side is closed and the reservoir portion 8 side is open. Further, on the outer peripheral surface of the wick 6, a plurality of grooves 11 extending in the longitudinal direction are provided over a region from the end on the steam pipe 4 side to the front of the end on the reservoir 8 side. As shown in FIG. 2, the plurality of grooves 11 are provided at equal intervals in the circumferential direction of the wick 6. Further, the outer diameter of the portion of the wick 6 where the groove 11 is not provided is set to a size slightly larger than the inner diameter of the housing of the evaporation portion 2. Therefore, when the wick 6 is housed in the evaporation unit 2, the wick 6 comes into close contact with the inner peripheral surface of the housing of the evaporation unit 2 in the portion where the groove 11 is not provided. In this way, since the wick 6 is in close contact with the housing of the evaporation unit 2, the heat of the heat generating portion is efficiently transferred to the wick 6 through the housing of the evaporation unit 2. The wick 6 also has a function of separating the liquid phase and the gas phase to prevent the working fluid of the gas phase from flowing back into the reservoir portion 8. On the other hand, in the portion where the groove 11 is provided, a space portion is formed between the groove 11 and the housing of the evaporation portion 2.

In the loop type heat pipe shown in FIG. 1, the working fluid of the liquid phase stored in the reservoir portion 8 permeates into the wick 6 due to the capillary phenomenon. In addition, due to this capillary phenomenon, the wick 6 also serves as a pump that sends the working fluid of the liquid phase from the condensing unit 3 to the evaporation unit 2. When the heat from the heat generating portion is transferred to the working fluid of the liquid phase that has permeated into the wick 6 through the housing of the evaporating portion 2, the working fluid evaporates due to the heat and changes to the gas phase. The working fluid that evaporates and changes to the gas phase is sent to the steam pipe 4 through the groove 11. Then, the working fluid of the gas phase is sent to the condensing portion 3 through the steam pipe 4. In the condensing portion 3, the heat of the working fluid passing through each flat tube 9 is released to the outside through the fins 10, so that the temperature of the working fluid is lowered and condensed, and the phase changes from the gas phase to the liquid phase. To do. The working fluid changed to the liquid phase moves to the evaporation section 2 through the liquid tube 5, and permeates into the wick 6 again from the reservoir section 8 due to the capillary phenomenon. By performing such circulation of the working fluid, the heat of the heat generating portion is continuously released to the outside, and the cooling target is cooled.

Next, the electronic device according to the embodiment of the present invention will be described.

FIG. 3 is a schematic configuration diagram of an electronic device according to the present embodiment.
As shown in FIG. 3, the electronic device 20 according to the present embodiment includes a heat generating portion 21 that generates heat when it is operated in order to exert its function. Here, the electronic device 20 is, for example, a mobile terminal device such as a mobile phone (including a device generally referred to as a smartphone), a laptop computer, a projection display device such as a projector, and the heat generating unit 21 is, for example. These include a CPU (Central Processing Unit) mounted on a notebook computer, a battery mounted on a mobile phone, and a light source mounted on a projector.

Further, the electronic device 20 according to the present embodiment includes the loop type heat pipe 1 as a cooling means for cooling the heat generating portion 21. The evaporation section 2 of the loop type heat pipe 1 is arranged so that the heat receiving section 7 is in contact with the heat generating section 21, and the heat receiving section 7 absorbs heat from the heat generating section 21.

Further, the electronic device 20 according to the present embodiment changes the heat generation amount of the heat generating portion 21 based on the posture sensor 22 as a posture detecting means for detecting the posture of the electronic device main body and the posture detected by the posture sensor 22. A control unit 23 that controls the operating state is provided. As the attitude sensor 22, for example, a gyro sensor (angular velocity sensor), an acceleration sensor, or the like is used.

Subsequently, the control of the electronic device according to the present embodiment will be described.

FIG. 4 shows a control flow of the electronic device according to the present embodiment.
As shown in FIG. 4, when the electronic device is activated, the posture is first detected by the posture sensor. Next, based on the detected posture, the control unit immediately performs normal operation, or operates so that the amount of heat generated by the heat generating unit is smaller than that during normal operation before performing normal operation. When it is decided whether to perform the operation and further, when it is decided to perform the low heat generation operation, the time for the low heat generation operation and the heat generation amount of the heat generating part during the low heat generation operation are determined based on the detected posture. To do. Specifically, the calorific value and the low heat generation operating time are determined based on the determination table shown in Table 1 below.

In the present embodiment, the cooling performance of the loop type heat pipe when the electronic device is operated in various postures is verified by experiments, and as shown in Table 1, the posture of the electronic device is the same as that of the condensing part in the evaporation part. It was classified into three patterns: a posture at the height of (posture 1), a posture in which the evaporation part is above the condensing part (posture 2), and a posture in which the evaporation part is below the condensing part (posture 3).

In the case of the posture (posture 1) in which the heights of the evaporation part and the condensation part are the same, it is assumed that the distribution of the gas phase and the liquid phase in the loop type heat pipe is in a desirable state. Specifically, the working fluid of the gas phase is filled from the outer space (groove) of the wick to the middle part of the steam pipe and the condensing part (flat pipe), and the liquid pipe from the middle part of the condensing part (flat pipe). The reservoir and the inner space of the wick are filled with the working fluid of the liquid phase, and a gas-liquid interface is formed near the outer surface of the wick. In this case, the cooling performance of the loop type heat pipe does not deteriorate. Therefore, as shown in Table 1, the heat generation amount of the heat generating part is set to the same heat generation amount Q as in the normal operation, and the time for performing the low heat generation operation is set to 0. doing. Therefore, in the case of the posture 1, the normal operation is immediately performed without performing the low heat generation operation.

On the other hand, in the case where the evaporation part is above the condensation part (posture 2), it is assumed that the distribution of the gas phase and the liquid phase in the loop type heat pipe is not in the desired state as described above. If it is done. Therefore, low heat generation operation is performed until the cooling performance of the loop type heat pipe is restored. In this case, as shown in Table 1, the calorific value of the heat generating portion is set to 50% of the calorific value Q during normal operation, and the low heat generation operating time is set to the predetermined time T. Here, the set calorific value (0.5 × Q) is a temperature at which the temperature of the heat generating portion does not exceed the allowable temperature upper limit even in the posture 2, and the set predetermined time (T) is thereafter. This is the time required for the temperature of the heat generating portion to decrease and converge to a constant value (time required for the cooling performance of the loop type heat pipe to recover) (see FIG. 5).

Further, even when the evaporation portion is in the posture below the condensing portion (posture 3), it is assumed that the distribution of the gas phase and the liquid phase in the loop type heat pipe is not in the desired state as described above. Is. Therefore, in this case as well, low heat generation operation is performed until the cooling performance of the loop type heat pipe is restored. However, since the situation is different from that of the posture 2, the heat generation amount of the heat generating portion and the low heat generation operating time are set separately from those of the posture 2. In this case, as shown in Table 1, the calorific value of the heat generating portion is set to 20% of the calorific value Q during normal operation, and the low heat generation operating time is set to 50% of the predetermined time T. The calorific value (0.2 × Q) of the heat generating portion here is a temperature at which the temperature of the heat generating portion does not exceed the allowable temperature upper limit value even in the posture 3, and the set time (0.5 × T). ) Is the time until the temperature of the heat generating portion drops and converges to a constant value (time until the cooling performance of the loop type heat pipe is restored).

Then, the control unit refers to the determination table shown in Table 1, selects the operating conditions corresponding to the detected posture, and operates the electronic device. That is, as shown in FIG. 4, in the case of the posture 1, the normal operation is performed without performing the low heat generation operation, and in the case of the posture 2, the heat generation amount is 50% of the heat generation amount Q in the normal operation for a predetermined time. Low heat generation operation is performed only for T, and in the case of posture 3, low heat generation operation is performed for 50% of the predetermined time T with a heat generation amount of 20% of the heat generation amount Q during normal operation.

In the case of posture 2 and the case of posture 3, each operation is switched to normal operation after performing low heat generation operation. At this point, it is assumed that the cooling performance of the loop type heat pipe has recovered, so that the operation can be continued without the heat generating portion exceeding the upper limit of the allowable temperature even if the operation is switched to the normal operation.

After that, in each case, when the operation is continued, the normal operation is continued, when the standby instruction is given, the operation is changed to the standby state, and when the stop instruction is given, the operation is stopped. Further, when an operation instruction is given after the standby state, the attitude is detected again, the operation condition is determined based on the detected attitude, and the operation is started, as in the above-mentioned flow. Further, even if an operation instruction is given after the stop, the attitude is detected again in the same manner, the operation condition is determined based on the detected attitude, and the operation is started. Further, the same applies when an operation instruction is given after the machine is stopped after waiting.

As described above, even if the electronic device according to the present embodiment is provided with a loop type heat pipe whose cooling performance varies depending on the posture of the electronic device main body, the posture of the electronic device main body is detected when the operation is started. This makes it possible to determine whether or not the loop type heat pipe is in a state where it can exhibit its original cooling performance. If it is determined that the loop type heat pipe cannot exhibit its original cooling performance based on the detected posture, the amount of heat generated by the heat generating part is higher than that during normal operation until the time when the cooling performance is expected to recover. It is possible to prevent the temperature of the heat generating portion from exceeding the allowable temperature upper limit value by performing the low heat generation operation. As described above, according to the electronic device according to the present embodiment, the loop type has a margin in performance by reducing the amount of heat generated by the heat generating portion of the electronic device according to the state in which the cooling performance of the loop type heat pipe is lowered. The temperature of the electronic device can be maintained within the permissible range without mounting a heat pipe, which is advantageous for cost reduction and miniaturization.

On the other hand, if it is judged that the original cooling performance can be exhibited, by performing normal operation without performing low heat generation operation, the user is not subject to unnecessary restrictions in terms of functionality or performance, and the electronic device is used. Equipment can be used.

Further, as in the present embodiment, by changing the amount of heat generated by the heat generating portion during low heat generation operation based on the detected posture state (type), the cooling performance of the loop type heat pipe is deteriorated according to the degree of deterioration. The amount of heat generated can be set. That is, when it is assumed that the cooling performance of the loop type heat pipe is lower, the heat generation amount of the heat generating part is set to be smaller to ensure that the temperature of the heat generating part exceeds the allowable temperature upper limit value. Can be prevented. On the other hand, if the cooling performance is not expected to deteriorate so much, it is possible to prevent the electronic device from being subject to unnecessary functional or performance restrictions by not suppressing the amount of heat generated by the heat generating part more than necessary. it can.

Further, as in the present embodiment, by changing the time for performing the low heat generation operation based on the detected posture state (type), it is possible to prevent the low heat generation operation time from becoming longer than necessary. At an early stage, the electronic device can be put into a state where it can perform its normal function or performance.

FIG. 6 shows another control flow of the electronic device.
In the control flow shown in FIG. 6, a portion surrounded by a broken line frame in FIG. 6 is added as compared with the control flow shown in FIG. 4 described above. Other than that, the control flow is almost the same as that shown in FIG. Hereinafter, a part different from the above-mentioned control flow will be mainly described.

In the control flow shown in FIG. 6, when the electronic device is in the standby state, the measurement of the standby time is started by a timer or the like. Then, when the standby state continues for a preset time, low heat generation operation is performed (see the broken line frame in FIG. 6). This low heat generation operation is performed during the standby state from the standby state to the subsequent instruction for shifting to the normal operation or the stop instruction, and from the stop state or the standby state as described above. It is different from the low heat generation operation during the normal operation transition, which is selectively performed when the transition to the normal operation. In addition, this low heat generation operation during standby is performed at predetermined time intervals, and until there is an instruction to shift to normal operation or a stop instruction, there are a state in which low heat generation operation is performed and a state in which low heat generation operation is not performed. Repeated.

On the other hand, if the standby state does not continue for a preset time, that is, if there is an instruction or a stop instruction for shifting to normal operation before the standby state continues for a preset time, the above The transition operation to the normal operation or the stop operation is started without performing the low heat generation operation during standby as in. In addition, if there is an instruction or stop instruction to shift to normal operation during execution of the standby low heat generation operation mode, the low heat generation operation mode is stopped and the transition operation or stop to normal operation is performed. Start operation.

As described above, in the control flow shown in FIG. 6, when the standby state continues for a preset time, the loop type heat pipe is caused by the posture of the electronic device in standby by performing low heat generation operation during standby. It is possible to suppress the deterioration of the cooling performance of. As a result, the cooling performance of the loop type heat pipe can be sufficiently maintained even during standby, and thereafter, when instructed to shift to normal operation, low heat generation operation is performed. It is possible to immediately shift to normal operation without any need.

The heat generation amount and the low heat generation operation time of the heat generating portion in the low heat generation operation during standby may be one preset heat generation amount and time, or based on the posture of the electronic device detected at the time of startup. It may be set individually. Further, in the control flow shown in FIG. 6, when operating (starting) from the stopped state, the flow is the same as the control flow shown in FIG. 4, and detailed description thereof will be omitted.

Although the embodiment of the electronic device according to the present invention has been described above, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

In the above-described embodiment, the postures of the electronic devices are classified into three patterns for control, but the postures are classified into two patterns, a posture that does not require low heat generation operation and a posture that requires low heat generation operation. May be controlled. Further, the postures may be further classified and the operating conditions may be set based on four or more patterns of postures.

Further, in the above description of the embodiment, as the electronic device whose posture changes, a mobile terminal device such as a mobile phone or a notebook computer, a projection display device such as a projector, or the like is given as an example, but the electronic device according to the present invention is used. Not limited to these electronic devices, it may be an electronic device mounted on a vehicle, an airplane, or the like. Since the postures of these electronic devices also change as the postures of automobiles and airplanes change, the above-mentioned actions and effects can be expected by applying the present invention.

1 Loop type heat pipe 2 Evaporation part 3 Condensation part 4 Steam pipe 5 Liquid pipe 6 Wick 20 Electronic equipment 21 Heat generation part 22 Posture sensor (posture detection means)
23 Control unit

Japanese Unexamined Patent Publication No. 2003-148882 Japanese Patent No. 5720338

Claims (1)

The heat generating part and
It has an evaporating part that absorbs heat from the heat generating part and evaporates the working fluid from the liquid phase to the gas phase, and a condensing part that condenses the working fluid of the gas phase derived from the evaporating part into the liquid phase. , A loop type heat pipe that recirculates the condensed working fluid of the liquid phase to the evaporation part,
It is an electronic device equipped with
Equipped with posture detection means to detect the posture of the electronic device body
When operating from a stopped state in which the operation is completely stopped, the amount of heat generated by the heat generating portion is reduced as compared with the normal operation before the normal operation is performed, based on the posture detected by the attitude detecting means. Decide whether or not to perform low heat generation operation
If the operation does not stop completely and waits for an instruction to restart or stop, and the standby state continues for a preset time, then an instruction or stop instruction to shift to normal operation is issued. The low heat generation operation is performed at predetermined time intervals until a certain time is reached.
An electronic device characterized in that, when instructed to shift from the standby state to normal operation, normal operation is performed without performing the low heat generation operation .