JP2012222112A - Display unit, and heat dissipation method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat dissipation efficiency when driving a blower means, even if another opening is provided in the vicinity of an opening for the blower means in order to improve heat dissipation efficiency when stopping the blower means.SOLUTION: A display unit 1 has a structure containing an LCD module 10 for displaying images by a bezel 2 and a rear cover 3. A fan unit 20 is located in the upper part of the back of the LCD module 10, and a circuit board 30 is located in the lower part of the back. An open hole 3a for a fan, which faces the fan unit 20, a lower open hole 3b, and an upper open hole 3c are formed in the rear cover 3. Passages A and B for sucking ambient air from the lower open hole 3b and exhausting it from the open hole 3a for the fan and the upper open hole 3c respectively when the fan unit 20 is stopped are formed. Also, passages D and E for sucking ambient air from the air intake hole of the fan unit 20 by suctioning it from the lower open hole 3b and the upper open hole 3c and exhausting it from the open hole 3a for the fan when the fan unit 20 is driven are formed.

Description

  The present invention relates to a heat dissipation structure and a heat dissipation method for a display device.

In a display device using a thin display panel such as a liquid crystal panel or a plasma panel, a chassis that reinforces the back surface of the display panel has a heat dissipation function. A circuit board for displaying an image on the display panel is mounted on the rear surface of the chassis. For this reason, a fan or the like is provided on the rear side of the chassis, and heat is dissipated by ventilation in the housing. 2. Description of the Related Art In recent years, devices that are becoming thinner have adopted a structure in which an axial fan with a large ventilation is mounted in a state parallel to a display surface. On the other hand, as a countermeasure against noise such as driving sound and wind noise caused by the installation of an axial fan, a method of variably controlling or stopping the rotation speed of the fan according to a temperature change due to a use environment or the like is known (Patent Document 1). reference).
Hereinafter, a configuration example of a conventional thin display device will be described with reference to FIG.
The display device 101 has a structure in which an LCD (Liquid Crystal Display) module 110 is accommodated by a front-side bezel 102 and a rear-side rear cover 103. The LCD module 110 includes a backlight unit 112 on the back side of the LCD panel 111, which is held by the chassis 113. The chassis 113 is formed of a plate material such as aluminum having good thermal conductivity, and has a function of transmitting heat generated by the backlight unit 112 to the back side to dissipate heat. An axial fan 120 is disposed at the upper back of the LCD module 110, and a circuit board 130 for transmitting a video signal to the LCD module 110 is attached below. On the back surface of the rear cover 103, a fan opening hole 103a is formed at a position facing the axial fan 120, and an opening hole 103b is formed in the lower part. A control unit (not shown) variably controls the rotational speed of the axial fan 120 or stops the axial fan according to a temperature detection signal of the temperature sensor 140 provided in the vicinity of the axial fan 120.
In addition, a structure that includes a sensor for detecting the propeller position of the fan and stops the propeller at a position where the opening ratio of the exhaust hole surrounded by the guard fence of the housing, the motor and the safety guard is maximized has been proposed (patent) Reference 2).

JP-A-11-095674 JP 2008-41802 A

By the way, the conventional heat dissipation structure when the fan is stopped is a natural air cooling system that takes outside air from the lower opening hole 103b shown in FIG. 7 and exhausts it from the fan opening hole 103a. Therefore, the exhaust opening area depends on the external dimensions and opening ratio of the fan and the number of mounted fans. In the structure shown in Patent Document 2, heat dissipation efficiency is improved by controlling the aperture ratio to be maximum when the fan is stopped. In order to further improve the heat dissipation efficiency when the fan is stopped, it is conceivable to provide an exhaust upper opening hole 103c in the vicinity of the fan opening hole 103a in the rear cover 103 shown in FIG. The upper opening hole 103c functions as an intake hole when the fan is driven. However, if the upper opening hole 103c is provided in the vicinity of the fan opening hole 103a, the ventilation path is shortened, so that the heat dissipation efficiency when the fan is driven may be reduced.
The object of the present invention is to improve the heat dissipation efficiency when driving the air blowing means even if another opening is provided in the vicinity of the opening for the air blowing means in order to improve the heat dissipation efficiency when the air blowing means is stopped. A heat dissipation structure and a heat dissipation method are provided.

  In order to solve the above problems, an apparatus according to the present invention is a display device in which an image display unit and a backlight unit are accommodated by an exterior member, and a blower unit attached to a back surface of the backlight unit; A drive control means for the blower means, a holding member that covers the blower means and has an exhaust hole facing the back side and an intake hole facing downward, and a position facing the exhaust hole of the blower means in the exterior member The formed first opening, the second opening formed below the first opening in the exterior member, and the third opening formed above the first opening in the exterior member Is provided. When the air blowing means is driven by the drive control means, there is a path for taking outside air from the second opening and the third opening, sucking it from the air intake hole of the air blowing means, and exhausting it from the first opening. It is formed.

  According to the present invention, even if the third opening is provided in the vicinity of the first opening for the air blowing means in order to improve the heat dissipation efficiency when the air blowing means is stopped, the heat radiation efficiency at the time of driving the air blowing means is improved. Can be made.

5A and 5B are a perspective view showing a thin display device and a perspective view showing a state in which a rear cover is removed in order to explain the first embodiment of the present invention in conjunction with FIGS. It is sectional drawing of a LCD module. It is the elements on larger scale which show a fan unit. FIG. 4 is a perspective view (A) showing a ventilation path when the fan is stopped and a perspective view (B) showing a ventilation path when the fan is driven. It is the perspective view (A) which shows the state which removed the rear cover of the thin display apparatus which concerns on 2nd Embodiment of this invention, and the elements on larger scale (B) which show a fan unit and a heat sink. FIG. 5A is a perspective view showing a ventilation path when a fan is stopped in a thin display device according to a second embodiment of the present invention, and a perspective view showing a ventilation path when the fan is driven. It is sectional drawing which shows the structural example of the conventional thin display apparatus.

[First Embodiment]
The structure of the thin display device according to the first embodiment of the present invention will be described below with reference to FIG. FIG. 1A is a perspective view when the display device 1 is viewed from the back side, and FIG. 1B is an exploded perspective view showing a state in which the rear cover 3 of the device housing is removed. In the following description, the front side as viewed from the user is the front side, and the opposite side of the display surface is the back side. Further, the right side when viewed from the user is the right side, the left is the left side, the upper side is the top side, and the lower side is the bottom side.
The display device 1 has a structure in which an LCD module 10 for displaying an image is accommodated by a front-side bezel 2 and a rear-side rear cover 3 that are exterior members. The display device 1 shown in FIG. 1A is supported by a stand 50, but the display device 1 can also be attached to a wall surface or the like from the back side with a wall bracket (not shown). On the back surface of the LCD module 10, as shown in FIG. 1 (B), a fan unit 20 as a blowing means is disposed at a position closer to the top. In this example, since the two circuit boards 30 are arranged below, the fan unit 20 is arranged for each of these circuit boards. The circuit board 30 is a board on which a circuit for transmitting a video signal is mounted on a display unit (not shown) of the LCD module 10. A fan opening hole 3a is formed as a first opening at a position where the display portion is exposed from the opening provided on the front side of the bezel 2 and opposed to the fan unit 20 on the back surface of the rear cover 3. A number of lower opening holes 3b arranged in the left-right direction are formed as second openings at positions near the lower end away from the fan opening holes 3a. A large number of upper opening holes 3c arranged in the left-right direction are formed as third openings above the fan opening holes 3a. About these opening holes, arbitrary shapes, such as a circular hole and a slit, may be sufficient.

Next, the LCD module 10 will be described using the longitudinal sectional view shown in FIG.
The LCD module 10 includes an LCD panel 11 and a direct backlight unit 12 on the back side thereof. The backlight unit 12 is configured using an LED substrate on which light emitting diodes (hereinafter referred to as LEDs) 12a are mounted at substantially equal intervals. The LCD panel 11 is sandwiched between a front case 13 and a rear case 14. The LCD panel 11 is exposed from the opening on the front side formed in the front case 13. The rear case 14 is a frame having an opening on the back side, and a chassis 15 that holds the backlight unit 12 is disposed. The backlight unit 12 is disposed in a space sealed by the LCD panel 11, the rear case 14, and the chassis 15. An optical member such as a diffusion plate or a reflection plate (not shown) is disposed between the LCD panel 11 and the backlight unit 12. The chassis 15 is formed of a plate material such as aluminum having good thermal conductivity, and has a function of transferring heat generated in the backlight unit 12 to the back side and dissipating it to the air. A plurality of bosses 15 a are provided on the rear surface of the chassis 15 in order to attach the fan unit 20 and the circuit board 30.

Next, the fan unit 20 will be described with reference to a partially enlarged view of FIG.
The fan unit 20 includes an axial fan 21 and its holder 22. The holder 22 has an enclosure portion 22E that holds the axial fan 21 and a duct portion 22D for intake air. The axial fan 21 is attached to the rear surface of the chassis 15 using the holder 22, and is held in a state parallel to the display surface of the LCD panel 11. In this example, an opening for sucking air is provided between the holder 22 and the chassis 15, and exhausted to the back side.
The shape of the surrounding portion 22E is a rectangular parallelepiped that covers the axial fan 21 from the top surface side, the back surface side, and the left and right side surfaces. The rear surface is a holding surface of the axial fan 21 and has a discharge hole 22a and a fixing screw hole 22b. The shape of the duct portion 22D is a truncated pyramid having a base that expands downward, and has an opening only on the bottom surface side for intake. In addition, attachment portions to the chassis 15 are extended on the left and right side surfaces of the surrounding portion 22E and the duct portion 22D, and a plurality of attachment holes 22c are formed. The holder 22 is attached to the boss 15a of the chassis 15 with a screw (not shown) through the attachment hole 22c.
A temperature sensor 23 is attached to the side surface of the duct portion 22D, and detects the temperature of the air flowing into the duct portion 22D. The axial fan 21 and the temperature sensor 23 are each connected to the circuit board 30 with a cable (not shown). The drive control unit 100 mounted on the circuit board 30 variably controls or stops the rotational speed of the axial fan 21 according to the temperature detection signal of the temperature sensor 23.

Next, the heat dissipation structure and effects of the display device 1 will be described with reference to FIG. FIG. 4A is a perspective view illustrating a ventilation path when the fan of the display device 1 is stopped. FIG. 4B is a perspective view for explaining a ventilation path when the fan is driven. Both figures are shown with the rear cover 3 seen through.
The main heat sources in the display device 1 are the backlight unit 12 and the circuit board 30, and the heat generated in the backlight unit 12 is transmitted to the chassis 15 and radiated to the air in the housing.
As shown in FIG. 4A, the heat dissipation structure in a state where the axial fan 21 is stopped takes outside air from the lower opening hole 3b of the rear cover 3, ventilates the inside of the housing, and opens the fan opening hole 3a and the upper opening. It is a structure of natural air cooling exhausted from the hole 3c. That is, one of the two types of ventilation paths is a path A from the lower opening hole 3b to the fan opening hole 3a, and the other is a path B from the lower opening hole 3b to the upper opening hole 3c. The exhaust hole area of the path A is determined by the outer dimensions and the opening ratio of the axial fan 21 and the number of the fans. For this reason, the heat radiation efficiency can be improved by increasing the area of the upper opening hole 3c that defines the exhaust hole area of the path B.
As shown in FIG. 4B, the heat dissipation structure when driving the axial fan 21 draws outside air from a part of the lower opening hole 3b and the upper opening hole 3c of the rear cover 3 and ventilates the housing. The structure is a forced air cooling structure that exhausts air from a part of the fan opening hole 3a and the upper opening hole 3c. That is, there are three types of ventilation paths D, E, and F. In paths D and E, air is exhausted from fan opening hole 3a, but in path F, it does not pass through fan opening hole 3a.
The path D is a path from the lower opening hole 3b to the fan opening hole 3a. The path E is a path from a part of the upper opening hole 3c to the fan opening hole 3a. The path F is a path from the lower opening hole 3b to the upper opening hole 3c. The upper opening hole 3c functioning as an exhaust hole when the fan is stopped also functions as an intake hole as shown by a path E, and the sucked air is axially extended from the opening on the bottom side along the outer shape of the duct portion 22D of the holder 22. It flows into the flow fan 21. As a result, the ventilation path becomes longer, so that the heat dissipation efficiency is improved. The path F has a function of preventing heat accumulation in a range not affected by the airflow from the axial fan 21. Depending on the structure and performance of the fan unit 20, there may be no path F.
According to the first embodiment, even when the opening member is provided in the upper portion of the exterior member in order to improve the heat dissipation efficiency when the fan is stopped, the heat dissipation efficiency when the fan is driven can be improved. Further, since the heat dissipation efficiency when the fan is stopped can increase the time for which the device is used while the axial fan is stopped, power consumption can be reduced.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described.
FIG. 5A is an exploded perspective view showing the display device 1 with the rear cover removed. Since the basic configuration is the same as that of the first embodiment, the differences will be mainly described below. In addition, about the part similar to the component demonstrated in 1st Embodiment, the detailed description is abbreviate | omitted by using the same code | symbol as the code | symbol already used.
On the back surface of the LCD module 10, a heat sink 40 is attached along the left-right direction at a position near the upper end. The fan unit 20 is disposed below the heat sink 40, and the circuit board 30 is disposed below the heat sink 40. The upper opening hole 3 c of the rear cover 3 is provided above the position corresponding to the heat sink 40 in the rear cover 3.

Next, the fan unit 20 and the heat sink 40 will be described with reference to a partially enlarged view of FIG.
The fan unit 20 includes an axial fan 21 and a holder 22 that is a holding member thereof. The axial fan 21 attached to the chassis 15 using the holder 22 is in a state parallel to the display surface of the LCD panel 11. A space for sucking air is formed between the chassis 15 and the axial fan 21 exhausts to the back side. The crank-shaped holder 22 has a discharge hole 22 a and a fixing screw hole 22 b formed in the holding portion of the axial fan 21. An intake hole 22d is formed in the support column bent at a right angle from the holding portion, and a mounting hole 22c to the chassis 15 is formed in the mounting portion bent outward.
A temperature sensor 23 is attached to the support column of the holder 22 and detects the temperature of the air flowing into the fan unit 20. The drive control unit 100 performs variable control or stop control of the rotational speed of the axial fan 21 according to the detected temperature. The heat sink 40 is fixed to the boss 15a of the chassis 15 by screw fastening above the fan unit 20. The heat sink 40 is made of aluminum or the like having good thermal conductivity, and a large number of fins 40a extend along the vertical direction. These fins 40a have a rectangular shape whose longitudinal direction is the vertical direction, are arranged at predetermined intervals along the left-right direction, and transfer heat to the air passing between the fins. The heat generated in the backlight unit 12 is transmitted to the heat sink 40 on the back via the chassis 15 and is radiated from the fins 40a to the air in the housing.

Next, the ventilation path will be described with reference to FIG. FIG. 6A is a perspective view illustrating a ventilation path when the fan of the display device 1 is stopped. FIG. 6B is a perspective view for explaining a ventilation path when the fan is driven. Both figures are shown with the rear cover 3 seen through.
As shown in FIG. 6A, when the fan is stopped, natural air cooling is performed in which outside air is taken in from the lower opening hole 3b of the rear cover 3, vented through the housing and the heat sink 40, and exhausted from the fan opening hole 3a and upper opening hole 3c. It has a structure. That is, one of the two types of ventilation paths is a path G from the lower opening hole 3b to the fan opening hole 3a. The other is a path H from the lower opening hole 3b to the upper opening hole 3c. The exhaust hole area of the path G is determined by the outer dimensions and the opening ratio of the axial fan 21 and the number of the fans. The heat dissipation efficiency of the heat sink 40 can be improved by increasing the area of the upper opening hole 3c that defines the exhaust hole area of the path H.
Further, as shown in FIG. 6B, when the fan is driven, outside air is sucked from a part of the lower opening hole 3b and the upper opening hole 3c of the rear cover 3, and the housing and the heat sink 40 are ventilated to open the fan opening hole 3a and The structure is such that air is exhausted from a part of the upper opening hole 3c. That is, there are three types of ventilation paths J, K, and L, and the paths J and K are exhausted from the fan opening hole 3a, but the path L does not pass through the fan opening hole 3a.
The path J is a path from the lower opening hole 3b to the fan opening hole 3a. The path K is a path from the upper opening hole 3c to the fan opening hole 3a. The path L is a path from the lower opening hole 3b to the upper opening hole 3c. The upper opening hole 3c functioning as an exhaust hole when the fan is stopped functions also as an intake hole as indicated by the path K, and outside air enters the housing from the upper opening hole 3c positioned above the heat sink 40. The heat sink 40 is cooled. Thereby, the heat dissipation efficiency of the heat sink 40 can be improved. Further, the path L functions so as not to generate heat accumulation in a range not affected by the airflow by the axial fan 21, but the path L may not exist depending on the structure and performance of the fan unit 20.
In an LCD module equipped with a direct backlight unit using a light source such as an LED or a display module such as a self-luminous plasma panel, the temperature tends to increase as it goes upward. These display modules have temperature characteristics. Due to non-uniform temperature distribution (temperature unevenness), display unevenness occurs in brightness, color, etc., and the lifetime may be shortened due to temperature rise. Therefore, in the present embodiment, the upper opening hole 3c is provided in order to improve the heat dissipation efficiency at the upper part of the apparatus when the fan is stopped. In this case, temperature unevenness can be reduced without lowering the heat dissipation efficiency at the top when the fan is driven. In addition, when the fan is stopped, the heat dissipation efficiency of the upper part can be increased by the heat sink 40, and the time for using the device in the fan stop mode can be lengthened.

DESCRIPTION OF SYMBOLS 1 Display apparatus 2 Bezel 3 Rear cover 3a, 3b, 3c Opening hole 10 LCD module 11 LCD panel 12 Backlight part 15 Chassis 20 Fan unit 21 Axial fan 22 Holder 40 Heat sink 100 Drive control part

Claims (7)

A display device in which an image display unit and a backlight unit are accommodated by an exterior member,
Air blowing means attached to the back of the backlight unit;
Drive control means for the blowing means;
A holding member that covers the air blowing means and has an exhaust hole facing the back side and an intake hole facing downward;
A first opening formed at a position facing the exhaust hole of the blowing means in the exterior member;
A second opening formed below the first opening in the exterior member;
A third opening formed above the first opening in the exterior member;
When the air blowing means is driven by the drive control means, there is a path for taking outside air from the second opening and the third opening, sucking it from the air intake hole of the air blowing means, and exhausting it from the first opening. A display device formed. When the air blowing means is stopped by the drive control means, the outside air that has entered the housing from the second opening is exhausted from the third opening and the outside air that has entered the housing from the second opening. Is formed through the intake hole and the exhaust hole of the blower means to be exhausted from the first opening,
When the air blowing means is driven by the drive control means, a path for sucking outside air from the second opening and exhausting it from the third opening and outside air are taken in from the second opening and the third opening. The display device according to claim 1, wherein a path for exhausting air from the first opening through the intake hole and the exhaust hole of the blowing unit is formed. The air blowing means is an axial fan arranged in parallel to the display surface of the display unit,
The display device according to claim 1, wherein the holding member includes an enclosure portion that covers the axial fan and has the exhaust hole, and a duct portion that has the intake hole. A display device in which an image display unit and a backlight unit are accommodated by an exterior member,
Air blowing means attached to the back of the backlight unit;
Drive control means for the blowing means;
A holding member that holds the air blowing means and has an exhaust hole facing the back side;
A heat dissipating means provided above the air blowing means;
A first opening formed at a position facing the exhaust hole of the blowing means in the exterior member;
A second opening formed below the first opening in the exterior member;
A third opening formed above the first opening in the exterior member;
A path for taking outside air from the second opening and the third opening and exhausting it from the first opening through the exhaust holes of the heat radiating means and the blowing means when the blowing control means is driven by the drive control means. Is formed.   When the air blowing means is stopped by the drive control means, the outside air that has entered the housing through the second opening is exhausted from the third opening through the heat radiating means and the second opening. The display device according to claim 4, wherein a path is formed in which outside air that has entered the housing is exhausted from the first opening through an exhaust hole of the blower. A heat dissipation method for a display device in which an image display unit and a backlight unit are accommodated by an exterior member,
An air blowing means is attached to the back surface of the backlight unit, the air blowing means is covered with a holding member, and an exhaust hole facing the back surface and an air intake hole facing the lower side are formed in the holding member,
The exterior member has a first opening at a position facing the exhaust hole of the blower, a second opening below the first opening, and a third opening above the first opening. Forming each
When the blowing unit is driven, outside air is taken in from the second opening and the third opening, sucked from the intake hole of the blowing unit, and exhausted from the first opening. Heat dissipation method. A heat dissipation method for a display device in which an image display unit and a backlight unit are accommodated by an exterior member,
A ventilation unit and a heat dissipation unit are attached to the back of the backlight unit, and an exhaust hole facing the back side is formed in the holding member of the ventilation unit,
The exterior member has a first opening at a position facing the exhaust hole of the blower, a second opening below the first opening, and a third opening above the first opening. Forming each
When the blower is driven, outside air is taken in from the second opening and the third opening, and exhausted from the first opening through the exhaust holes of the heat dissipating means and the blower. Heat dissipation method for the device.

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