Plasma display device

A plasma display device includes a chassis base supporting a plasma display panel (PDP). A heat conducting medium is interposed between the chassis base and the PDP, and a heat sink presses toward the heat conducting medium through the penetration hole.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 2003-59209 filed on Aug. 26, 2003 at the Korean Intellectual Property Office, the entire contents of which is incorporated herein by reference.

BACKGROUND

The present invention relates to a plasma display device, and more particularly to a plasma display device having an enhanced heat radiation structure.

(b) Description of the Related Art

As is well known in the art, a plasma display device realizes a desired image using a plasma discharge. Such a plasma display device generally includes a plasma display panel (PDP) for rendering the desired image through plasma discharge activated by an external power source, a chassis base for firmly holding the PDP at its front side, and circuit boards mounted on a rear side of the chassis base for driving the PDP. Front and rear cases are combined with front and rear sides of a PDP module (i.e., a combination of a PDP, a chassis base, and circuit boards)to form such a plasma display device.

Since rendering of a desired image by a PDP is achieved using a plasma discharge as described above, a PDP generally produces a significant amount of heat during its image rendering. A PDP may be damaged when a temperature of thereof increases excessively, so heat dissipation efficiency of a PDP plays an important role in its durability. In this sense, increasing heat dissipation of a PDP has always been an important research topic in the field.

Examples of heat dissipation mechanisms of a PDP may be found in numerous prior technical documents, for example in Laid Open Japanese Patent publication 09-097015 (applicant: MATSUSHITA ELECTRIC IND CO. LTD, date of publication: Apr. 8, 1997), and Laid Open Korean Patent publication 1998-0011613 (applicant: MATSUSHITA ELECTRIC IND CO. LTD, date of publication: Apr. 30, 1998).

As can be gathered from the technical documents, a heat dissipation mechanism of a plasma display device according to the prior art may be generally summarized as follows.

A chassis base is formed of a metal (e.g., aluminum or a compound thereof) having high heat conductivity such that heat generated at a PDP may be easily dissipated. A heat transferring material such as a heat dissipation sheet is disposed between the PDP and the chassis base such that the heat generated at the PDP may be easily transferred to the chassis base. A heat dissipation member (e.g., a heat sink or cooling fins) is attached to a rear side of the chassis base such that a dissipation effect of heat occurs through a front side thereof from the PDP. Therefore, the heat generated at the PDP is transferred to the chassis base through the heat dissipation sheet, and is finally dissipated at the heat dissipation member.

According to such a heat dissipation mechanism of the prior art, when the chassis base and the PDP are attached interposing the heat dissipation sheet, air is frequently trapped to form a layer therebetween. This results from wide areas of the chassis base and the PDP having difficulty forming uniformly close contact therebetween at all spots, and in addition, because a sufficiently high pressure applied for attachment may easily cause damage to the PDP.

In order to reduce formation of such an air layer between the PDP and the chassis base interposing the heat dissipation sheet, according to the prior art, slits for discharging air are frequently formed at the heat dissipation sheet, or the thickness of the heat dissipation sheet is varied in different areas.

However, such features do not sufficiently prevent the occurrence of such an air layer at areas that need to be cooled by dissipating heat. That is, such an air layer is still frequently formed at some locations of the wide PDP-attached area that are unpredictable and uncontrollable.

Different amounts of heat are generated at the PDP at different areas and, accordingly, a surface temperature of the PDP becomes different at different areas. It is therefore preferable that a heat dissipation mechanism of a plasma display device be enhanced such that heat dissipation efficiency may be determined and controlled appropriately, depending on the area of need.

Another problem presented by the prior art heat dissipation mechanism is that negative effects of the dissipated heat on circuit boards mounted on a rear side of the chassis base are ignored, since the general concern has only been about dissipation of heat generated at the PDP. The heat of the PDP is dissipated mainly through the rear side of the chassis base, and such dissipated heat affects elements included in the circuit boards mounted at the rear side of the chassis base. That is, the heat of air heated at the rear side of the chassis base is easily transferred to the elements of the circuit boards mounted at the rear side of the chassis base, e.g., through leads on the surface of the circuit boards.

Therefore, a reduction of heat transfer from a chassis base to a circuit board may enhance the stability and durability of a plasma display device.

SUMMARY

An exemplary plasma display device according to an embodiment of the present invention includes a plasma display panel (PDP), a chassis base for supporting the PDP and having at least one penetration hole, a heat conducting medium interposed between the chassis base and the PDP, and a heat sink disposed at the penetration hole and pressing toward the heat conducting medium.

In a further embodiment, such a plasma display device further includes a conjoining device formed at one side of the chassis base, and forming a pressure of the heat sink toward the heat conducting medium and conjoining with the heat sink. In some embodiments, the heat sink is conjoined with the conjoining device directly, and in other embodiments, the heat sink is conjoined with the conjoining device by at least one interposed member.

In a still further embodiment, a plurality of projections is formed on the heat sink.

When the heat sink is conjoined with the conjoining device through at least one interposed member, the at least one member may cover the plurality of projections.

An air passage of a generally vertical direction may be formed by the plurality of projections

In another still further embodiment, the heat sink and/or the at least one interposed member have at least one boss formed in a direction opposite to the chassis base. In this embodiment, at least one circuit board is conjoined to the boss.

The conjoining device may include a conjoining boss, and in one embodiment, a sum of a thickness of the chassis base and a height of the conjoining boss may be smaller than a distance between an area of the heat sink facing the conjoining boss and an area of the heat sink facing the heat conducting medium.

The conjoining device may also include a conjoining boss and an elastic member. In this embodiment, at least part of the elastic member is disposed proximate to an upper end of the conjoining boss.

In some embodiments, the elastic member includes a rubber member disposed on the upper end of the conjoining boss or a spring disposed generally coaxially with the conjoining boss.

A heat dissipation unit may alternatively replace the heat sink and be disposed at the penetration hole by at least part thereof and press toward the heat conducting medium.

In a further embodiment, the plasma display device further includes a conjoining device formed at one side of the chassis base, forming a pressure of the heat dissipation unit toward the heat conducting medium. The heat dissipation unit may be conjoined to the rear side of the chassis base by the conjoining device.

In a still further embodiment, a plurality of projections is formed at the heat dissipation unit. An air passage of a generally vertical direction may be formed by the plurality of projections, which may also project in a direction opposite to the chassis base. The heat dissipation unit may include a plate member for covering the plurality of projections.

In another still further embodiment, at least one boss is formed at the heat dissipation unit in a direction opposite to the chassis base, and at least one circuit board is conjoined to the boss. In this case such conjoined circuit board can become more thermally stable.

The conjoining device may include a conjoining boss, and a sum of a thickness of the chassis base and a height of the conjoining boss may be smaller than a distance between an area of the heat dissipation unit facing the conjoining boss and an area of the heat dissipation unit facing the heat conducting medium.

The conjoining device may include a conjoining boss and an elastic member, and at least part of the elastic member is disposed proximate to an upper end of the conjoining boss.

The elastic member may include a rubber member disposed on the upper end of the conjoining boss or a spring disposed generally coaxially with the conjoining boss.

DETAILED DESCRIPTION

As shown inFIG. 1, a plasma display device according to a first embodiment of the present invention includes a chassis base100, a plasma display panel (PDP)190attached at a front side110of the chassis base100and supported thereby, and a heat conducting medium195interposed between the chassis base100and the PDP190such that heat generated at the PDP190may be transferred to the chassis base100.

The heat conducting medium195may be a heat dissipation sheet, as is well known in the art. However, one skilled in the art will understand that the heat conducting medium may be any suitable shape or substance capable of conducting heat.

Penetration holes130are formed in an interior of the chassis base100.FIG. 1shows eight (8) penetration holes130of a rectangular shape. However, one skilled in the art will understand that any suitable number and shapes of the penetration holes130may be substituted for those shown in the pictured embodiments.

A heat sink150is disposed at each penetration hole130and is pressurized toward the heat conducting medium195.

A conjoining device310(refer toFIGS. 3–6) is formed at a rear side120of the chassis base100, for forming pressure on the heat sink150toward the heat conducting medium195such that the heat sink150is pressurized to the heat conducting medium195. The conjoining device310is described below in further detail.

FIG. 2is an enlarged perspective view of the heat sink150used in a plasma display device according to a first embodiment of the present invention.

As shown inFIG. 2, a plurality of projections210are formed on the heat sink150. According to such projections210, a heat dissipating area of the heat sink150is enlarged and therefore a heat dissipating effect thereof is enhanced.

In this embodiment, the projections210are shaped as ribs having vertical walls, and the rib-shaped projections210are aligned in a vertical direction of the plasma display device. Therefore, air passages215of rectangular cross-sections are vertically formed by the ribs of the heat sink150. Air heated by the heat sink150has a tendency to rise along the air passages215formed by the ribs, and therefore, the projections210have a function of guiding the heated air.

In addition, conjoining holes220are formed near edges of the heat sink150, for conjoining the heat sink150to the chassis base100.

FIG. 3is a sectional view ofFIG. 1along a line III—III, and shows a conjunction structure of the heat sink150and the chassis base100of a plasma display device.

As shown inFIG. 3, a conjoining device310for conjunction to the heat sink150is formed at the rear side120of the chassis base100.

In the embodiment shown inFIG. 3, the conjoining device includes a conjoining boss320formed at the rear side120of the chassis base100. The conjoining boss320and the conjoining hole220described above with respect to the heat sink150are formed at corresponding positions.

A lower side330of the heat sink150shown inFIG. 3contacts the heat conducting medium195through the penetration hole130of the chassis base100, and the heat sink150contacting the heat conducting medium195as such is held by a screw fastener325to engage with the conjoining boss320through the conjoining hole220.

The pressure of the heat sink150pressing the heat conducting medium195may be controlled by, e.g., a thickness t of the chassis base100, a height h of the boss320, and a thickness of the heat sink150. Control of the pressure of the heat sink150to the heat conducting medium195, by such a mechanical specification of the boss320, the heat sink150, and the chassis base100, is hereinafter described in further detail with reference toFIG. 4.

As shown inFIG. 4, a distance between a rear side410of the boss320and the front side110of the chassis base100, that is, a sum of a thickness t of the chassis base100and a height h of the boss320, is smaller than a distance between the upper side410of the boss320and the lower side330of the heat sink150. In other words, a sum of a thickness t of the chassis base100and a height h of the boss320is smaller than a distance between an area of the heat sink150facing the boss320and an area of the heat sink150facing the heat conducting medium195.

Therefore, when the heat sink150is firmly conjoined to the boss320, the lower side330of the heat sink150slightly protrudes toward the heat conducting medium195by a distance d with respect to the lower side110of the chassis base100. Due to such a protrusion, the heat sink150may be pressurized to the heat conducting medium195.

In one embodiment the pressure between the lower side330of the heat sink150and the heat conducting medium195is set according to the thickness of the heat conducting medium195. In another embodiment, this pressure may be set by choosing a specific value of the protrusion distance d. As an example, the protrusion distance d may be set as a value between 0.15 mm to 0.5 mm.

InFIG. 4, the conjoining device310is shown to include only the boss320, and the pressure of the heat sink150to the heat conducting medium195is formed by a specification, such as height h of the boss320

However, it is within the scope of the present invention to form the pressure between the heat sink150and the heat conducting medium195through any suitable means and in reference to any suitable specification.

Exemplary variations of the conjoining device310of a plasma display device are shown inFIGS. 5 and 6. The conjoining devices310′ and310″ include conjoining bosses520and620and elastic members530and630, respectively, and the elastic members530and630are disposed above upper ends of the conjoining boss520and620by at least part thereof.

For example, according to the variation shown inFIG. 5, the boss520has a smaller height than the boss320shown inFIGS. 3 and 4, and includes a rubber member530disposed on an upper end of the boss520.

In the variation shown inFIG. 6, the boss620has smaller height than the boss320shown inFIGS. 3 and 4, and includes a coil spring630disposed generally coaxially around the boss620.

In conjoining devices310′ and310″, the pressure between the heat sink150and the heat conducting medium195may be varied by fastening (or tightening) the screw fastener325when the heat sink150is conjoined to the bosses520and620by the screw fastener325.

According to such variations, a sum of a thickness t of the chassis base100and a height h of either of the conjoining boss520and620is also smaller than a distance between an area of the heat sink150facing either of the conjoining bosses520and620and an area (i.e., the lower side330) of the heat sink150facing the heat conducting medium195.

The heat sink150presses the heat conducting medium195through the penetration hole130formed at the chassis base100, as shown inFIG. 1, and, therefore, contact between the heat sink150and the heat conducting medium195may be enhanced. In addition, the positions of the penetration holes130may be designed to be concentrated near a center of the PDP190that produces the most heat, so that uniformity of the surface temperature of the PDP190may also be enhanced.

In an embodiment shown inFIGS. 7 and 8, one or more circuit boards720are mounted to the rear side of the chassis base900.

The PDP990, the heat conducting medium995, the chassis base900, the heat sink950, and the conjoining device310, are similar to those described above in relation toFIGS. 1–6. The embodiment shown inFIGS. 7 and 8further includes a heat dissipation guide plate710for covering the heat sink950, and a circuit board720mounted on the heat dissipation guide plate710.

Such a mounting structure of the heat dissipation guide plate710and the circuit board720to the chassis base900is hereinafter described with reference toFIG. 8.

FIG. 8is a sectional view ofFIG. 7along a line XI—XI. As shown inFIG. 8, a second boss820for mounting the heat dissipation guide plate710is formed at the rear side of the chassis base900, and the heat dissipation guide plate710is mounted to the chassis base900through the second boss820.

In addition, a third boss830for mounting a circuit board720is formed on the heat dissipation guide plate710, and the circuit board720is mounted to the heat dissipation guide plate710through the third boss830.

In the embodiment shown inFIG. 8, a gap d2is formed between the heat dissipation guide plate710and the heat sink950. However, such a gap can alternatively be excluded.

Regardless of whether such a gap is formed or not, interposing the heat dissipation guide plate710between the heat sink950and the circuit board720may prevent convective heat transfer from the heat sink950to the circuit board720.

With reference toFIGS. 1 to 8, the heat sinks150,950are shown and described as if they are directly conjoined to the conjoining devices310,310′,310″. However, the heat sinks150,950may also be conjoined to the conjoining devices310,310′,310″ by interposing one or more members between them.

In addition, although the heat dissipation guide plates710,710′ and the heat sinks150,950have been described as separate members mounted to the chassis base900, they may also be formed as a unit (i.e., a unit body) and may be mounted to the chassis bases100,900as such.

The embodiment ofFIG. 9shows an exemplary structure of a plasma display device in which a heat sink is unified with a heat dissipation guide plate and is mounted to a conjoining device interposing at least one member. The external features of the plasma display device inFIG. 9, when assembled, are similar to those shown inFIG. 7. The embodiment shown inFIG. 9, includes a chassis base900, a plasma display panel (PDP)990attached at a front side of the chassis base900and supported thereby, and a heat conducting medium995interposed between the chassis base900and the PDP990such that heat generated at the PDP990may be transferred to the chassis base900.

The heat conducting medium995may be a heat dissipation sheet, as is well known in the art.

Penetration holes930are formed in an interior of the chassis base900. As described with respect toFIGS. 1–8, the scope of the present invention should not be understood to be limited to the number of the penetration holes930and their shapes as shown inFIG. 9.

This embodiment also includes a heat dissipation unit710′ for dissipating heat transferred from the heat conducting medium995through the penetration holes930.

The heat dissipation unit710′ is disposed at the penetration holes930by at least part thereof (refer to heat sinks1050ofFIG. 10) and is pressurized toward the heat conducting medium995. A conjoining device1110(refer toFIG. 11) is formed at a rear side of the chassis base900, for forming a pressure on the heat dissipation unit710′ toward the heat conducting medium995such that the heat dissipation unit710′ is pressurized to the heat conducting medium995. The conjoining device1110is described below in further detail.

FIG. 10shows a side of the heat dissipation unit710′ which would face a chassis base900ofFIG. 9. As shown inFIG. 10, the heat dissipation unit710′ includes a heat dissipation guide plate1010and heat sinks1050, wherein the heat sinks1050are welded to the heat dissipation guide plate1010. Such heat sinks1050are disposed at positions corresponding to the penetration holes930, so they are pressurized to the heat conducting medium995.

Similar to the heat sinks150,950described with respect toFIGS. 1–8, the heat sinks1050include a plurality of projections1051, and the plurality of projections1051vertically form heat dissipation passages1052.

In the above description, the heat sinks1050of the heat dissipation unit710′ are described to be welded to the heat dissipation guide plate1010. However, they may also be coupled to the heat dissipation guide plate1010through other means, such as die-casting.

The plurality of projections1051project from a side of the heat dissipation unit710′ contacting the heat conducting medium995, and they project therefrom in a direction opposite to the chassis base900. Therefore, the projections1051can dissipate heat received from the heat conducting medium995.

In addition, the heat dissipation guide plate1010covers the plurality of projections1051, and therefore it prevents air heated by the plurality of projections1051from moving toward the circuit board720.

FIG. 11is a sectional view ofFIG. 7along a line XI—XI. As shown inFIG. 11, a conjoining device1110conjoins the heat dissipation guide plate1010to the chassis base900. A conjoining boss1120is formed at the chassis base900. The conjoining boss1120and the conjoining hole1020described above with respect to the heat dissipation unit710′ are formed at corresponding positions.

A lower side1130of the heat dissipation unit710′ contacts the heat conducting medium995through the penetration hole930of the chassis base900, and the heat dissipation unit710′ firmly contacts the heat conducting medium995and is held by a screw fastener (not shown) engaging with the conjoining boss1120through the conjoining hole1020.

In addition, a second boss1125for mounting the circuit board720is formed at the heat dissipation guide plate1010, and the circuit board720is mounted at the heat dissipation guide plate1010through the second boss1125.

A small clearance is formed between the projections1051of the heat sink1050and the heat dissipation guide plate1010, such that heat conduction from the projections1051to the heat dissipation guide plate1010may be minimized.

As described with respect toFIGS. 1–8, the pressure of the heat dissipation unit710′ (in more detail, the heat sink1050) pressing the heat conducting medium995may be controlled by a specification such as a thickness t3of the chassis base900, a height h3of the boss1120, and a thickness of the heat sink1050.

As shown inFIG. 12, a sum of the thickness t3of the chassis base900and the height h3of the boss1120is smaller than a distance between an area of the heat dissipation unit710′ facing the boss1120and an area1130of the heat dissipation unit710′ facing the heat conducting medium995.

As described above, a person of ordinary skill in the art may tailor the pressure by which the heat dissipation unit710′ is pressured to the heat conducting medium995and the protrusion distance d3to suit their particular needs.

Exemplary variations1110′ and1110″ of the conjoining device are shown inFIGS. 13 and 14. The conjoining devices1110′ and1110″ include conjoining bosses1320and1420and elastic members1330and1430, respectively, and the elastic members1330and1430are disposed above upper ends of the conjoining boss1320and1420by at least part thereof.

For example, according to the variation shown inFIG. 13, the boss1320has a smaller height than the boss1120shown inFIGS. 11 and 12, and instead, a rubber member1330is disposed on an upper end of the boss1320.

In addition, according to the variation shown inFIG. 14, the boss1420has a smaller height than the boss1120shown inFIGS. 11 and 12, and instead, a coil spring1430is disposed generally coaxially around the boss1420.

The pressure from the heat dissipation unit710′ to the heat conducting medium995may be varied by an amount of fastening (or tightening) of a screw fastener when the heat dissipation unit710′ is conjoined to the bosses1320and1420by the screw fastener.

As shown inFIGS. 13 and 14, a sum of a thickness t3of the chassis base900and a height h3of either of the conjoining bosses1320and1420is also smaller than a distance between an area of the heat dissipation unit710′ facing either of the conjoining bosses1320and1420and an area1130of the heat dissipation unit710′ facing the heat conducting medium995.

As described above, contacting of heat sinks and a heat conducting medium is enhanced because heat sinks having an area smaller than a PDP are pressed directly to a heat conducting medium.

Heat dissipation may become more efficient at a high temperature region of a PDP, and therefore, temperature deviation and average temperature of a PDP may be lowered.

In addition, air heated by heat sinks may be efficiently exhausted since projections of the heat sinks form air passages.

Furthermore, heating of a circuit board by convection of air heated by the heat sinks may be prevented due to a heat dissipation guide plate that covers the projections of the heat sinks.

The pressure of the heat sinks pressing the heat conducting medium may be easily controlled by setting a specification such as heights of bosses for mounting the heat sinks.

In addition, a tolerance that may be produced during a manufacturing process of a plasma display device may be easily absorbed since the pressure of heat sinks against the heat conducting medium may be easily adjusted due to elastic members between bosses and heat sinks.

Heat sinks and a heat dissipation guide plate may be formed as a unit such that the heat dissipation mechanism may become thinner, and therefore a total thickness of a plasma display device may be decreased.

Although exemplary embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that many variations and/or modifications of the basic inventive concept taught herein, which may appear to those skilled in the art, will still fall within the spirit and scope of the present invention, as defined in the appended claims.