JP2009116202A - Image display device - Google Patents

Abstract

【Task】
Even an image display device with a larger screen, higher brightness, higher definition, and thinner thickness will increase the cooling effect and reduce noise.
[Solution]
A flat display panel 1, a display surface side cover 2 installed on the display surface side of the display panel, a non-display surface side cover 3 installed on the non-display surface side, and a display drive substrate 7 are provided. The image display device includes an opening 4 provided on at least one side of the display surface side cover 2, a cavity portion 12 communicated with the opening 4, and a vibrator 9 provided in the cavity portion 12. By vibrating the child 9, a vortex ring is generated along the display surface of the display panel 1.
[Selection] Figure 1

Description

  The present invention relates to an image display device, and is particularly suitable for efficiently radiating heat from a flat display panel such as a plasma display or a display drive substrate.

  Planar image display devices such as plasma displays are required to have larger screens and higher brightness and definition of images, which increases the heat generated by the display panel and the display drive substrate. Therefore, it is necessary to sufficiently cool these heat generating components.

  In order to increase the amount of cooling as the amount of heat generated increases, it is known to install a cooling fan for exhaust on the ceiling of the cover on the non-display surface side and exhaust the exhaust heat of the display panel and display drive board to cool it. For example, it is described in Patent Document 1.

  Further, it is known that a cooling fan is installed on the ceiling surface of the back cover, and cooling is performed by passing air from between the display panel and the protective material to the display surface side of the display panel through a duct. ing.

  Furthermore, as one of the cooling promotion methods, improvement of the heat transfer coefficient accompanying the turbulent flow can be considered, and in order to promote the turbulent transition of the flow, it is necessary to provide various protrusions serving as turbulence sources on the plane. The structure of a vertical vortex generator for generating a vertical vortex and a tripping wire in which a wire is mounted on the wing surface has been put into practical use for a long time in aircraft wings.

  However, since the tripping wire 16 and the vertical vortex generator 17 have no moving parts, it is necessary to install them in a place where the flow is developed to some extent, and in order to promote cooling, they must be installed on the image display surface. This hinders image display at the installation location.

Japanese Patent Laid-Open No. 2005-235843 JP 2006-330196 A

  In the above-described Patent Document 1, in a larger-sized flat image display device, the total heat generation amount increases with the increase in brightness and definition of the image, and a plurality of cooling fans are installed to cope with this. In order to perform cooling or enhance the cooling effect, it is necessary to increase the number of fan rotations, install more cooling fans, increase the size of the fan, etc. , Installation space and cooling fan drive input increase. Therefore, in the structure in which the cooling fan is installed on the back side, there is a limit to the amount of heat that can be handled.

  In addition, in the device described in Patent Document 2, since the cooling fan is used to ventilate the panel display surface side, a flat image display device having a high need for thinning should secure a space for installing the cooling fan and the ventilation duct. However, it has not been practically used in a larger-sized flat image display device.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems of the prior art and to enhance the cooling effect even in an image display device having a larger screen, higher brightness, higher definition, and thinner thickness.

  Another object is to provide a large amount of cooling and low noise.

  Another object is to increase the reliability of an image display device with a larger screen, higher brightness, and higher definition.

  The present invention is to achieve at least one of the above objects.

  In order to solve the above problems, the present invention provides a flat display panel, a display surface side cover installed on the display surface side of the display panel, a non-display surface side cover installed on the non-display surface side, In an image display device comprising a display drive substrate, an opening provided on at least one side of the display surface side cover, a cavity connected to the opening, and a vibrator provided in the cavity And a vortex ring is generated along the display surface of the display panel by vibrating the vibrator.

  According to the present invention, since a vortex ring is generated along the display surface of the display panel, the cooling effect is enhanced even in an image display device having a larger screen, higher brightness, higher definition, and thinner thickness. No fan is required and noise can be reduced.

  In order to promote cooling without providing a cooling fan and a ventilation duct on the panel display surface side, it is preferable to improve the heat transfer coefficient by turbulent flow on the panel display surface side. However, the flow on the panel display surface side is equivalent to natural convection along a vertical flat plate, and according to empirical laminar and turbulent flow criteria, the panel surface required for natural transition to turbulent flow The height is about 1.4m. This is an extent of a turbulent transition at the top of an ultra-large flat image display device of 100V type or higher, and a large flat image display device of about 20-60V type used in general homes is heated in the whole area. A laminar flow having a low transmissibility is formed.

  Further, a projection is provided on the panel display surface side of the flat image display device, disturbs natural convection to promote turbulent transition, and installs a tripping wire and a vertical vortex generator on the display panel 1 of the large flat display device. It is possible. However, the protrusion becomes an obstacle, which affects the image display of that portion, resulting in a reduction in the commercial value of the image display device.

  Therefore, a vortex ring generator using a vibrator is installed near the panel display surface, vortex rings are periodically generated along the panel display surface, and natural convection is turbulently transitioned by strong disturbance generated locally by the vortex ring. That is good.

  Hereinafter, an embodiment will be described in detail with reference to the drawings.

  In FIG. 1, 1 is a display panel, 2 is a display surface side cover, 3 is a non-display surface side cover, 4 is an opening provided in the display surface side cover 2, 5 is a stand, 6 is a frame in FIG. 3 is a vortex ring generator, 9 is a vibrator, 10 is a fixed wall, 11 is a vibration wall, 12 is a cavity surrounded by the fixed wall 10 and the vibration wall 11 and communicated with the opening 4. , 13 is a vortex ring.

  In the image display apparatus, the surface on which the image is displayed on the display panel 1 in FIG. 1 corresponds to the display surface (front side), and the surface on which the display drive substrate 7 on the back side of the display panel 1 is installed is the non-display surface (back surface). . The display panel 1, the display surface side cover 2, and the non-display surface side cover 3 are fixed to a frame 6 and supported as a whole by a stand 5. The display panel 1 is supplied with signals and power from the display driving substrate 7 via a cable (not shown) and displays an image. The display panel 1 and the display driving substrate 7 are main heat sources of the image display device.

  In the case of a flat display device, the heat generation is the same without any particular limitation, and the display panel type is, for example, a display panel such as a plasma display, a liquid crystal display, or an organic EL display. That is, since the display panel 1 serves as a heating element, the temperature of the display panel 1 rises, and a flow from the bottom to the top is generated on the front side by natural convection.

  FIG. 4 shows heat transfer characteristics by natural convection of a vertical flat plate for a uniform heat transfer surface temperature that is widely used in general. The horizontal axis represents the local Rayleigh number Ra_x with respect to the distance x from the lower end of the flat plate, and the vertical axis represents The value is obtained by multiplying the local Nusselt number Nu_x, which is a dimensionless amount of heat transfer coefficient, by the ratio of the kinematic viscosity of air at the wall surface temperature and the ambient temperature (ν_w / ν_∞) ^ 0.21.

  4 to 26V type, 42V type, 65V type, etc., large flat image display devices of a size normally used in ordinary households have a laminar flow up to the upper end of the panel, and high heat transfer characteristics can be obtained. The turbulent flow is not reached. In order to start transition to turbulent flow, a flat plate height of 1.4 m is required, which corresponds to the fact that turbulent transition finally occurs at the top of the 103V type panel, which is an ultra-large flat image display device. Figure 4 summarizes the experimental data obtained under conditions where the flow field disturbance is small. If artificial disturbance is applied, turbulent transition can be achieved with a lower local Rayleigh number. it can.

  In order to give a disturbance, as shown in FIG. 3, a vortex ring generator 8 comprising a fixed wall 10, a cavity 12 surrounded by a vibrating wall 11 that vibrates by a vibrator 9, and an opening 4 is provided. As shown in FIG. 1, at least one opening 4 is installed in the display surface side cover 2 in a direction along the display surface on the display surface side of the display panel 1. A plurality of display panels may be installed in the left-right direction of the display panel.

  The vibrator 9 uses a piezo element or an electrostrictive polymer, for example, and operates upon receiving an input from a drive circuit (not shown). When the vibrator 9 vibrates, the volume of the cavity 12 varies periodically as shown in FIG. At this time, when the vibrator 9 is deformed to the outside of the cavity portion 12, the volume of the cavity portion 12 increases, so that air is taken into the cavity portion 12 from the opening 4.

  When the vibrator 9 is deformed inside the cavity 12, the volume of the cavity 12 is reduced, and the vortex ring 13 is discharged from the opening 4. Therefore, a very strong flow is locally generated around the vortex ring in the direction in which the vortex is wound, which becomes a disturbance source. Moreover, it moves as a relatively long distance vortex ring with respect to the representative diameter of the vortex ring. As it moves, the vortex ring deforms and eventually disappears, but in the process it promotes mixing and diffusion around it. The vortex ring generating device having such a configuration is in principle the same as what is called a Synthetic Jet or a Zero-net-mass-flux Jet device.

  By periodically vibrating the vibrator 9, the vortex ring generator 8 continuously generates the vortex ring 13 as shown in FIG. 3, and against the natural convection of laminar flow originally formed by the heat generation of the display panel 1. Turbulence and promote turbulent transition of flow. As a result, the heat transfer coefficient on the front side of the display panel 1 is improved, and the temperature of the display panel 1 can be reduced.

  Further, the vortex ring generator 8 can be a simple and small device composed of the vibrator 9, the fixed wall 10, and the vibration wall 11, has high mountability, and is ventilated by a cooling fan on the front side of the display panel 1. A space such as a duct necessary for mounting is not required for the structure to be performed.

  Further, unlike a device such as a cooling fan that increases the wind speed in a wide range at the same time and realizes an improvement in the heat transfer rate by itself, the vortex ring generator 8 periodically gives a strong disturbance locally, Since it promotes the inherent nature of turbulent transition, it functions only with the vibration of the vibrator 9. Accordingly, the input can be operated at a few W at most, and a relatively high cooling effect can be obtained with a small input. The addition of the disturbance by the vortex ring generator 8 does not require any structure in the image display section of the display panel 1 unlike projections such as a tripping wire or a vertical vortex generator, and thus hinders image display. There is nothing to do.

  The display panel 1 is installed on the upper side of the display panel 1 as shown in FIG. 5, for example, and the opening 4 is provided downward and the vortex ring 13 is generated downward. It is also good. In this case, the upward natural convection and the downward vortex ring 13 are opposed to each other, but the vortex ring 13 does not disappear immediately after the occurrence of vortex preservation, and travels a predetermined distance on the upper portion of the display panel 1. To do. In this process, the disturbance is further increased due to the interference with the opposing natural convection, and the mixing of the air near the room temperature of the outside air and the high temperature air near the display panel 1 is promoted, and the temperature rise is likely to cause a problem. Cooling of the top of the is particularly facilitated.

  Further, since the opening 4 faces downward, minute dust or the like enters and accumulates inside the hollow portion 12, or a large amount of moisture accidentally enters the opening 4 at the time of cleaning at home, so that the vibrator 9 is electrically connected. There is no risk of breakage and the like, and the reliability of the vortex ring generator 8 and the maintainability as an image display device can be improved.

  In FIG. 6, a protective member 14 is provided on the display surface side of the display panel 1 through a gap 15, and the opening 4 of the vortex ring generator 8 is formed on the display surface side cover 2 in a direction along the protective member surface outside the protective member 14. It is installed.

  In some large planar image display devices such as a plasma display, a gap 15 is provided on the display surface side of the display panel 1 in preparation for an unexpected situation such as an external object colliding and the display panel 1 being damaged. A protective member 14 made of glass or the like is installed. The gap 15 is partitioned so that dust does not enter, and air is contained therein. The movement of the heat generated in the display panel 1 to the display surface side is performed by convection and radiation of air in the gap 15, the temperature of the protection member 14 rises, and natural convection and radiation from the outer surface of the protection member 14. To dissipate heat to the outside of the image display device.

  The vortex ring generator 8 provided at the lower portion of the gap 15 generates the vortex ring 13 along the outer surface of the protection member 14. Thereby, a disturbance is added to the natural convection of the laminar flow from the bottom to the top, and the transition of the turbulent flow is promoted. Therefore, the heat transfer rate on the outside of the protective member 14 is improved, and the heat radiation amount is increased, whereby the temperature of the display panel 1 can be reduced.

  Still another embodiment will be described with reference to FIGS. In FIG. 8, 4a is an opening provided in the display surface side cover 2 outside the protective member 14, 4b is an opening provided between the protective member 14 and the display panel 1, 10a is a fixed wall including the opening 4a, 10b. Is a fixed wall including the opening 4b, 12a is a cavity including the opening 4a, and 12b is a cavity including the opening 4b.

  In the vortex ring generator 8, the cavity 12 a and the cavity 12 b share the vibrating wall 11 and the vibrator 9. Therefore, when the vibrating wall 11 is deformed to the cavity 12a side, the vortex ring 13a is released from the opening 4a, and a flow of sucking air into the cavity 12b is generated from the opening 4b, and the period is shifted by half a wavelength. The vortex ring 13a and the vortex ring 13b are discharged alternately from 12a and 12b.

  The opening 4a is installed on the outside of the protective member 14 and in the direction along the protective member surface, and the opening 4b is installed on the display panel 1 display surface side and in the direction along the display surface. One vortex ring generator 8 or a plurality of vortex ring generators 8 are installed in the horizontal direction of the display panel 1, and the vibrator 9 uses, for example, a piezo element or an electrostrictive polymer, and receives an input from a drive circuit (not shown). To do.

  In this example, a single vibrator 9 generates vortex rings as disturbance sources not only on the outer surface of the protection member 14 but also on the display panel 1 side surface of the protection member 14 and the display surface of the display panel 1. The area of the heat transfer surface where the transfer rate is improved is greatly increased, and the cooling characteristics are improved. Furthermore, since the size of the vortex ring generating device 8 itself is originally small and only the fixed wall 10b is added, the size does not increase so much, so that the mountability is excellent.

  Still another embodiment will be described with reference to FIGS. The hollow portion 12a and the hollow portion 12b share the vibrating wall 11 and the vibrator 9, and the vortex ring 13a and the vortex ring 13b are alternately emitted from the 12a and 12b in a state in which the period is shifted by a half wavelength, thereby forming the vortex ring generator 8. .

  The opening 4a is installed in the direction along the display surface side of the display panel 1 and the display panel, and the opening 4b is installed in the direction along the non-display surface side and the non-display surface of the display panel 1. One vortex ring generator 8 or a plurality of vortex ring generators 8 are installed in the left-right direction of the display panel 1. The vibrator 9 uses, for example, a piezo element or an electrostrictive polymer, and operates in response to an input from a drive circuit (not shown). .

  In many large flat image display devices such as liquid crystal and organic EL, the display panel 1 is often exposed to the outside as shown in FIG. 9 without installing the protective member 14 as shown in FIG.

  In this example, the vortex ring as a disturbance source is generated not only on the display surface of the display panel 1 but also on the non-display surface of the display panel 1 by the single vibrator 9, so that the heat transfer surface that improves the heat transfer coefficient is obtained. The area is greatly increased and the cooling characteristics are improved. Furthermore, since the size of the vortex ring generator 8 itself is originally small and only the fixed wall 10b is added, it is excellent in mountability.

  As described above, when a group of vortex rings periodically generated from a vortex ring generator having an opening on the display surface side cover moves along the panel display surface, the laminar flow originally formed by natural convection on the panel display surface side is changed. A very strong disturbance can be given locally and turbulent transition can be promoted. In the turbulent flow, the mixing in the direction perpendicular to the main flow is promoted, so that the heat transfer coefficient is improved with respect to the laminar flow, and the cooling from the display panel surface side can be promoted. Further, since the vortex ring generator is not installed on the display panel surface, it does not affect the image display.

  Furthermore, the vortex ring generator has a simple structure in which an opening and a vibrator are provided in the hollow portion, so that it can be miniaturized and can be mounted without requiring a duct that is required when a fan is ventilated. Are better. Also, unlike the cooling fan, it does not improve the wind speed itself, but promotes the nature of the turbulent transition inherent in the fluid, so it can operate with low input to the cooling fan. There is.

The perspective appearance figure of one example by the present invention. The principal part sectional drawing of one Example by this invention. Sectional drawing which shows the vortex ring generator in one Example by this invention. The figure which shows the heat transfer characteristic in the natural convection of a vertical flat plate. The perspective appearance figure of one example by the present invention. Sectional drawing of the principal part of the other Example by this invention. The principal part sectional drawing of other Example by this invention. Sectional drawing which shows the vortex ring generator of further another Example by this invention. The principal part sectional drawing of other Example by this invention. Sectional drawing which shows the vortex ring generator of further another Example by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display panel 2 Display surface side cover 3 Non display surface side cover 4, 4a, 4b Opening 5 Stand 6 Frame 7 Display drive board 8 Vortex ring generator 9 Vibrator 10, 10a, 10b Fixed wall 11 Vibration wall 12, 12a, 12b Cavity part 13, 13a, 13b Vortex ring 14 Protection member

Claims (7)

An image display device comprising: a flat display panel; a display surface side cover installed on the display surface side of the display panel; a non-display surface side cover installed on the non-display surface side; and a display drive substrate. In
An opening provided on at least one side of the display surface side cover;
A cavity communicated with the opening;
A vibrator provided in the cavity,
And an vortex ring is generated along the display surface of the display panel by vibrating the vibrator.   2. The image display device according to claim 1, wherein the vibrator is periodically driven.   2. The image display device according to claim 1, wherein a plurality of the openings, the hollow portions, and the vibrator are provided on a lower side of the display panel. 3.   2. The image display device according to claim 1, wherein a plurality of the openings, the hollow portions, and the vibrator are provided on the upper side of the display panel. 3.   The image display device according to claim 1, further comprising: a protective member provided on a display surface side of the display panel via a gap, and generating a vortex ring along an outer side of the protective member. .   2. The display device according to claim 1, further comprising: a protection member provided on a display surface side of the display panel via a gap, wherein the opening is provided outside the protection member and between the protection member and the display panel. And an vortex ring is generated along the outside of the protective member and between the protective member and the display panel.   The opening according to claim 1, wherein the opening is opened on the display panel display surface side and the non-display surface side, and a vortex ring is generated along the display panel display surface side and the non-display surface side. An image display device.

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