JP5443024B2 - Display device - Google Patents

Description

  The present invention relates to a display device characterized by a method of arranging a heat dissipation mechanism of a backlight unit.

  2. Description of the Related Art Conventionally, a liquid crystal display device in which a backlight unit is disposed on the back side of a liquid crystal panel has been used as a display unit for various instruments and navigation systems disposed on an automobile console. The backlight unit includes a light guide plate disposed on the back surface of the liquid crystal panel and a plurality of LEDs (Light Emitting Diodes) serving as light sources on the side end surfaces of the light guide plate. Is guided into the light guide plate and emitted from the surface of the light guide plate to the liquid crystal panel as illumination light. In the case of a liquid crystal display device equipped with such a backlight unit, when the operating environment of the liquid crystal panel becomes high, the display performance and life of the liquid crystal display device deteriorate. Therefore, a mechanism for radiating heat stored in the backlight unit (hereinafter referred to as heat dissipation). It is necessary to provide a mechanism) (see, for example, Patent Document 1).

  FIG. 10 shows an example of a liquid crystal display device provided with a conventional heat dissipation mechanism.

  The liquid crystal display device includes a known liquid crystal panel 24 such as a TFT liquid crystal, a backlight unit 25 that illuminates the liquid crystal panel 24, a circuit board 28, and the liquid crystal panel 24, the backlight unit 25, and the circuit board 28. The upper case 22 and the lower case 23 are housed, and the backlight unit 25 is provided with a heat dissipation mechanism that dissipates heat generated when the LED 30 as a light source is turned on.

  The upper case 22 includes a rectangular top plate 22a formed of a metal such as stainless steel, and a wall portion 22b extending around the top plate 22a. A central portion of the top plate 22a includes the liquid crystal panel 24. An opening 22c that exposes the display area is formed. The lower case 23 includes a rectangular bottom plate portion 23a made of a metal such as aluminum and a wall portion 23b erected around the bottom plate portion 23a.

  The backlight unit 25 is provided with an intermediate case 26 for reinforcing a case having an upper surface that is an arrangement direction of the liquid crystal panel 24 opened.

  On the substantially rectangular bottom plate 26a of the intermediate case 26, a heat radiating plate 31, a reflecting sheet (not shown), a light guide plate 27 and an optical sheet (not shown) as a heat radiating mechanism are stacked and stored in order. An opening 26c is formed at the center of the bottom plate 26a to expose the lower surface of the heat radiating plate 31 stacked in the lowermost layer.

  The heat radiating plate 31 is made of an aluminum substrate, and one side of the heat radiating plate 31 has an appropriate gap, that is, a gap in which the circuit board 32 on which the LED is mounted can be disposed. It is formed as a wall portion 31b that is erected from the floor plate portion 31a on which the reflection sheet, the light guide plate 27, and the like are placed, by being bent toward the arrangement side of the liquid crystal panel 24 so as to face each other. An FPC (Flexible printed circuits) as a circuit board 32 on which a plurality of LEDs 30 are mounted is attached to the inner surface of the wall portion 31b, that is, the surface facing the side end surface serving as the incident surface of the light guide plate 27. The LEDs 30 are arranged in the longitudinal direction of the incident surface of the light guide plate 27 stacked on the upper layer.

  In the present embodiment, the lower surface of the floor plate portion 31a of the heat radiating plate 31 is provided with a screwing portion (not shown) for fixing to the lower case 23, and the lower case 23 and the heat transfer sheet (not shown). A surface contact portion (not shown) that is in surface contact via the contact) is formed.

  Then, the upper case 22 is attached from the liquid crystal panel 24 side in a state where the liquid crystal panel 24 is superimposed on the upper surface of the light guide plate 27 via an optical sheet, and each member is engaged with the lower case 23. Is housed in a case 21 and formed as a liquid crystal display device.

  In the liquid crystal display device configured as described above, the heat generated by the LED 30 is transmitted to the heat radiating plate 31 through the circuit board 32 on which the LED 30 is mounted, and is radiated from the heat radiating plate 31.

JP 2006-235179 A

  By the way, in recent years, so-called high current type LEDs corresponding to 150 mA are used as the light source in response to a demand for higher luminance of the display unit. However, this high current type LED has a large amount of heat generation, so if this heat generation is not efficiently dissipated, the operating environment of the liquid crystal panel becomes high temperature, and as a result, a high luminance display cannot be obtained and the display performance is deteriorated. May end up.

  Accordingly, an object of the present invention is to provide a display device including a heat dissipation mechanism that can radiate heat more reliably and efficiently and can contribute to downsizing of the display device with a simple configuration. .

In order to solve the above-described problems, the display device of the present invention includes an upper case and a lower case, and faces the liquid crystal panel, the light guide plate, and a side end surface serving as an incident surface of the light guide plate in the lower case. A display device including a backlight unit having a light source to be arranged, a long heat radiation member body having a plate-like heat pipe structure, and a shaft portion and a locking head integrally formed with the heat radiation member body a plate-like heat dissipation member having a plurality of engaging projections formed of the parts, the light source is formed by a plurality of LED are arranged on one side of the heat dissipation member main body, wherein the backlight unit Comprises a rectangular bottom plate portion and a wall portion erected around the bottom plate portion, and includes an intermediate case for storing the light guide plate, and the intermediate case is disposed at the central portion of the wall portion on the light source side. Corresponds to the LED array length of the light source With wall openings are formed Te, wherein the bottom plate portion and the bottom plate opening by continuously is formed in the wall opening, the lower case heat radiating portion at least partially made of highly thermally conductive material An engagement hole for engaging the engagement protrusion is formed in the heat dissipation portion, and the plate-like heat dissipation member engages the engagement protrusion with the engagement hole, the Rukoto is engaged with the locking head of the engaging protrusion which projects from the engagement hole in the lower case are fixed to face the light source to the entrance surface and comprising a side end surface of the light guide plate It is characterized by.

The display device configured as described above efficiently radiates the heat generated by the light source by the heat pipe structure of the plate-like heat radiating member, and stores the heat stored in the plate-like heat radiating member to the heat radiating portion of the case via the engaging protrusion. By transmitting, the heat generated by the backlight unit is dissipated. By isosamples and the like to rotate the connecting portion between the shaft portion and the locking head of the engaging projections is engaged with the locking head in the lower case, the plate-like heat radiating member with respect to the case Can be disposed firmly and reliably, and the thermal contact area can be increased, so that the heat radiation efficiency can be improved.

Further, another display device of the present invention includes an upper case and a lower case, and a light source disposed opposite to a liquid crystal panel, a light guide plate, and a side end surface serving as an incident surface of the light guide plate in the lower case. A display device including a backlight unit having a long heat radiation member body having a plate-like heat pipe structure, and a plurality of pin-like engagement protrusions integrally formed on the heat radiation member body. The light source is formed by arranging a plurality of LEDs on one surface side of the heat radiating member body , and the backlight unit has a rectangular bottom plate portion and a periphery of the bottom plate portion. And an intermediate case that houses the light guide plate, and the intermediate case has a wall surface corresponding to the arrangement length of the LEDs of the light source at a central portion of the wall portion on the light source side. An opening is formed , Said bottom plate portion being a bottom plate opening by continuously formed on the wall surface opening, the lower case is constituted by at least the heat radiating portion a part of the bottom plate portion is made of a high thermal conductivity material, the heat dissipation the part, with the engagement hole is formed for fitting the engaging protrusion, the bottom plate portion of the lower case, the engagement of the engaging projections when the is fitted to the engagement hole The region in which the engagement hole is formed is positioned higher than the region in which the intermediate case is accommodated so that the front end portion of the joint protrusion does not protrude outward from the lower surface of the bottom plate portion in the region in which the intermediate case is accommodated. is formed in a stepped shape which is, the plate-like heat dissipation member, by fitting the engaging protrusion in the engaging hole, it is opposed to the light source side end face serving as the incident surface of the light guide plate characterized in that it is fixed inside the lower case Te

Even in the display device configured as described above, the heat radiation of the light source is efficiently radiated by the heat pipe structure of the plate-like heat radiating member, and the heat storage of the plate-like heat radiating member is radiated from the case via the engaging protrusion. The heat generated by the backlight unit is dissipated by transmitting to Then, by fitting the distal end portion of the engaging projections with the engaging hole, it is possible to easily and reliably disposing the plate-shaped heat radiating member with respect to the case, moreover, in comparison with the conventional heat radiation mechanism heat Therefore, the heat dissipation efficiency can be improved.

Another display device according to the present invention includes an upper case and a lower case, and a light source disposed in the lower case so as to face a liquid crystal panel, a light guide plate, and a side end surface serving as an incident surface of the light guide plate. a display device having a backlight unit having, a plate-like heat dissipation member elongated radiating member body is formed with a plate-shaped heat pipe structure, the light source is on one side of the heat dissipation member main body The backlight unit is formed by arranging a plurality of LEDs, and the backlight unit includes a rectangular bottom plate portion and a wall portion standing around the bottom plate portion, and includes an intermediate case that houses the light guide plate. The intermediate case has a wall surface opening corresponding to the arrangement length of the LEDs of the light source in the central portion of the wall portion on the light source side, and the bottom plate portion is continuous with the wall surface opening. Let the bottom plate opening Made is are, the lower case is made of a rectangular bottom plate portion and the periphery standing wall portion of the bottom plate portion is constituted by a heat radiating portion at least partially made of high thermal conductivity material, the heat radiating portion The abutting portion that extends from the wall portion side of the lower case located on the light source side to the opposite wall portion side and abuts against the plate-like heat radiating member is cut out. The plate-like heat radiating member is pressed toward the opposing wall portion of the lower case by the urging force of the contact portion, and is sandwiched between the intermediate case and fixed in the lower case. It is characterized by.

  In the display device configured as described above, the heat pipe structure of the plate-shaped heat radiating member efficiently radiates the heat generated by the light source, and the heat storage of the plate-shaped heat radiating member is transferred to the heat radiating portion of the case via the contact portion. By transmitting, it becomes possible to dissipate the heat generated by the backlight unit.

  As described above, by bringing the contact portion made of a high thermal conductivity material constituting the heat radiating portion of the case into contact with the plate-shaped heat radiating member, the thermal contact area can be made larger than that of the conventional heat radiating mechanism. Therefore, it is possible to improve the heat dissipation efficiency.

Then, further, the abutting portion is formed in a plate spring shape, said contact portion is brought into contact with the opposite side of the one surface side of the light source is disposed in the plate-like heat dissipation member, said light source It is made to oppose the side end surface used as the entrance plane of the light-guide plate accommodated in the intermediate case .

  In the display device configured as described above, the plate-like heat radiation member can be easily and reliably disposed in the case by the plate spring-like contact portion.

  As described above, according to the display device of the present invention, since heat can be radiated more reliably and efficiently, an excessively high temperature of the operating environment of the liquid crystal panel can be prevented and a high brightness display can be realized. It becomes possible.

Further, since the plate-like heat radiating member acting as the main heat radiating mechanism is fixed to the case by “engagement ( fitting )” or “pressing / clamping ”, it is extremely simple.

  Moreover, as the heat dissipation mechanism, a plate-shaped heat dissipation member having a size facing the side end surface that is the incident surface of the light guide plate and a display device case that is thermally connected to the plate-shaped heat dissipation member are used. The heat dissipation mechanism has a very compact design and can contribute to downsizing of the display device.

The principal part disassembled perspective view of the display apparatus of 1st Embodiment of this invention. A perspective perspective view for explaining a method of structural fixation and thermal connection between a lower case and a plate-like heat radiation member as a heat radiation portion in the first embodiment A perspective enlarged perspective view for explaining a method of structural fixing and thermal connection between a lower case as a heat radiating portion and a plate-like heat radiating member in the first embodiment. A perspective perspective view for explaining a method of structural fixation and thermal connection between a lower case and a plate-like heat radiating member as a heat radiating portion in the second embodiment A perspective enlarged perspective view for explaining a method of structural fixing and thermal connection between the lower case and the plate-like heat radiating member as the heat radiating portion in the second embodiment. An elevational perspective view of a lower case as a heat dissipating part in the third embodiment The perspective view for demonstrating the method of structural fixation and thermal connection with the lower case and plate-shaped heat radiating member as a thermal radiation part in 3rd Embodiment. The principal part top view explaining the method of structural fixation and thermal connection with the lower case and plate-shaped heat radiating member as a heat radiating part in 3rd Embodiment It is a graph for demonstrating the effect regarding the high brightness | luminance of the display apparatus of this invention, (a) is a graph which shows the relationship between the current of derating in the conventional display apparatus used as a comparison object, and temperature, (b) is. The graph which shows the relationship between the electric current and temperature in the display apparatus of this invention, (c) is a graph which shows the relationship between the electric current and temperature in the case of performing the derating similar to the past in the display apparatus of this invention. Main part exploded perspective view of a conventional display device

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is an exploded perspective view of a main part of the display device according to the first embodiment of the present invention.

The display device 1 of this embodiment includes an upper case 2 and a lower case 3, and includes a liquid crystal panel 4 and a backlight unit 5 disposed on the back side of the liquid crystal panel 4 in the lower case 3. ing.

  In the present embodiment, the upper case 2 includes a rectangular top plate 2a formed of a metal such as stainless steel and a wall portion 2b provided around the top plate 2a, and the center of the top plate 2a. An opening 2c for exposing the display area of the liquid crystal panel 4 is formed in the part.

  The lower case 3 is entirely formed of aluminum metal having good thermal conductivity and is configured to function as a heat radiating portion in the liquid crystal display panel, and is erected on the rectangular bottom plate portion 3a and its periphery. Wall portion 3b. In the present embodiment, the bottom plate portion 3a is formed with a plurality of engagement holes 3c for engaging engagement protrusions 9b formed on the plate-like heat radiation member 9 described later.

  As the liquid crystal panel 4, a liquid crystal panel 4 having a known configuration such as a TFT type liquid crystal panel 4 is used.

  In addition, the backlight unit 5 includes an intermediate case 6 including a substantially rectangular bottom plate portion 6a and a wall portion 6b erected around the bottom plate portion 6a. On the bottom plate portion 6a, A reflection sheet (not shown; not necessary when the bottom plate portion 6a functions as a reflection plate, etc.), a light guide plate 7, an optical sheet (not shown), and the like are stacked and stored. Yes. And in this embodiment, in order to make the emitted light of LED10 as a light source enter into the incident surface 7a which is the one side end surface of the light-guide plate 7, according to the arrangement length of LED10, the intermediate case which becomes the light source side side A wall surface opening 6c is formed by cutting out the central portion of the wall portion 6b of the wall 6, and is continuous with the wall surface opening 6c so as to position an engagement protrusion 9b formed on a plate-like heat radiation member 9 described later. Thus, the bottom plate portion 6a is cut out in a U shape to form a bottom plate portion opening 6d.

  A boss (not shown) having a screw hole is integrally formed on the bottom surface of the bottom plate portion 6a of the intermediate case 6 so as to protrude. A circuit board 8 and a gasket (not shown) for driving the liquid crystal panel 4 and the like are appropriately disposed between the bottom plate portion 3a of the lower case 3 and screw holes formed in the lower case 3. It is screwed using a screw (not shown) in a state of being aligned with (not shown).

And in this embodiment, the side end surface used as the entrance plane 7a of the said light-guide plate 7 in which the elongate plate-shaped heat radiating member 9 which has a heat pipe structure in plate shape was laminated | stacked on the bottom-plate part 6a of the said intermediate | middle case 6. Are arranged to face each other. In the present embodiment, the plate-like heat radiating member 9 is erected in the intermediate case 6 so that both ends in the longitudinal direction thereof are along the wall portion 6b in which the wall surface opening 6c of the intermediate case 6 is formed. ing.

  A plurality of LEDs 10 as light sources are mounted on the surface of the plate-like heat radiating member 9 facing the light guide plate 7 so as to be arranged in the longitudinal direction of the side end surface of the light guide plate 7, and the LEDs 10 are turned on. A control circuit for controlling is formed. That is, in the present embodiment, the plate-like heat radiating member 9 is formed so as to also serve as a circuit board of the LED 10.

Here, the plate-like heat radiating member 9 is formed of a high thermal conductivity material, the heat pipe structure (e.g., capillary structure) is a heat spreader having a plate-like, in one side of LED10 as a heat source is disposed The main body of the heat dissipating member that can move heat by evaporating the volatile liquid (working fluid) enclosed in the heat pipe and absorbing heat and condensing the working fluid on the other side to release heat 9a and a plurality of engaging protrusions 9b that are structurally fixed to the lower case 3 and thermally connected to the lower case 3 are integrally formed.

  Specifically, as shown in FIGS. 2 and 3, the engaging protrusion 9b is provided on one side surface in the longitudinal direction of the heat radiating member main body 9a, which is on the lower case 3 side when the plate-like heat radiating member 9 is disposed. A plurality (four in FIGS. 1 and 2) are formed at equal intervals. The formation position and number of the engagement protrusions 9b correspond to the formation position and number of the engagement holes 3c formed in the lower case 3.

Each engaging projection 9b includes a shaft portion 9ba extending from the heat radiating member main body 9a and a locking head portion 9bb having a longitudinal intermediate portion connected to the tip of the shaft portion 9ba. The overall shape is substantially T-shaped. More specifically, the shaft portion 9ba is in a state where the plate-like heat radiating member 9 is erected in the intermediate case 6 so that both ends in the longitudinal direction are along the wall portion where the wall surface opening 6c is formed. The length of the engaging head 9bb protruding out of the lower case 3 from the engaging hole 3c formed in the lower case 3 through the bottom plate opening 6d opening in the bottom plate 6a of the intermediate case 6. (See FIG. 3). Further, the locking head portion 9bb is formed as a small piece portion extending in the longitudinal direction of the heat dissipating portion main body 9a of the plate-like heat dissipating member 9 before being engaged with the engaging hole 3a. Then, the locking head portion 9bb which is the tip portion of the engaging projection portion 9b is protruded from the engaging hole 3c, and the connecting portion with the shaft portion 9ba is approximately parallel to the bottom plate portion 3c of the lower case 3. By rotating 90 °, the locking head portion 9bb is locked to the lower case 3 (locked state), and the plate-like heat radiating member 9 is fixed to the housing 1. As a result, a heat transfer path is formed from the heat radiating member main body 9a to the lower case 3 made of aluminum via the shaft portion 9ba and the locking head portion 9bb of the engaging projection portion 9b.

Further, the upper case 2 is attached from the liquid crystal panel 4 side in a state where the liquid crystal panel 4 is overlapped on the upper surface of the light guide plate 7 through optical sheets, and is fitted to the lower case 3. The members are integrated to form the liquid crystal display device 1.

The liquid crystal display device 1 configured as described above transmits the heat generated by the LED 10 from the one surface side where the LED 10 is disposed to the other surface side of the back surface by the plate-like heat pipe structure of the heat radiating member main body 9a. The heat is dissipated toward the wall surface opening 6c, and is transmitted from the heat radiating member main body 9a to the lower case 3 through the shaft portion 9ba and the locking head portion 9bb of the engaging projection 9b, and from the lower case 3 to the outside. Dissipate heat. Therefore, even when a so-called high-current type LED 10 is used, heat is radiated more reliably and efficiently than in a liquid crystal display device having a conventional heat radiation mechanism, and the arrangement of the LEDs 10 of the plate-like heat radiation member 9 is reduced. It is possible to prevent the installation side from being overheated. Therefore, it is possible to prevent display performance from being deteriorated due to overheating of the operating environment of the liquid crystal panel 4 and realize high-luminance display. Further, the display device with this configuration eliminates the need for a heat sink in the configuration of the conventional display device described above. Furthermore, since the fixing method of the plate-like heat radiating member 9 is extremely simple, if a problem such as non-lighting of the LED 10 occurs, the replacement work of the plate-like heat radiating member 9 can be simplified. There is also.

  In the present embodiment, the engaging protrusion 9b is formed in a T-shape including a shaft portion 9ba and a locking head portion 9bb, and the shaft portion 9ba portion is plastically deformed by rotation, so that the locking head portion is formed. The portion 9bb is engaged with the engagement hole 3c to be in a locked state. For example, the engagement protrusion 9b is formed in a small piece, and a portion protruding from the engagement hole 3c is bent. It is good also as a structure made into a locked state by crimping. Furthermore, although the intermediate case 6 is disposed in the present embodiment, the intermediate case 6 is not an essential configuration of the present invention and can be omitted.

Further, the plate-like heat dissipation member 9 in which the LEDs 10 are disposed is only required to allow the LEDs 10 to face each other on the incident surface 7a of the light guide plate 7 in the liquid crystal display device 1, as in the present embodiment. Even when the intermediate case 6 is provided, the intermediate case 6 is not limited to being disposed inside the intermediate case 6 but may be disposed outside the wall surface opening 6c.

  Furthermore, in the present embodiment, the LED 10 is directly disposed on the heat radiating member body 9a of the plate-like heat radiating member 9 formed also as a circuit board. However, a circuit board such as an FPC is provided separately. A desired number of LEDs 10 may be disposed on the FPC, and the FPC may be attached to the surface of the heat radiating member main body 9 a facing the light guide plate 7.

  In the present embodiment, the lower case 3 itself of the liquid crystal display device 1 is formed of aluminum having good thermal conductivity to constitute a heat radiating portion, and heat is transmitted to the lower case 3 itself. The portion where the engagement locking portion 9b of the plate-like heat radiating member 9 is thermally connected, that is, the region where the engagement hole 3c is formed is formed of another metal or a high heat conductive material, and can dissipate heat. What is necessary is just to be made into the heat dissipation part. For example, a heat radiating portion may be provided in the intermediate case 6 or the upper case 22.

  4 and 5 are perspective explanatory views of a mechanism for fixing the plate-like heat radiating member 9 to the lower case 3 of the liquid crystal display device 1 in the liquid crystal display device according to the second embodiment of the present invention. Hereinafter, the main part of the present invention, which is different from the first embodiment, will be described, and the description of the same components as those of the above-described embodiment will be omitted.

In the liquid crystal display device 1 of the second embodiment, the bottom plate portion 3a of the lower case 3 is engaged with the engagement so that the plate-like heat radiating member 9 provided with the LEDs 10 is arranged outside the intermediate case 6. The bottom plate portion 3aa serving as a region for forming the hole 3c is formed in a step shape, which is positioned one step higher than the bottom plate portion 3ab of the region for housing the intermediate case 6 of the lower case 3. Then, the region for forming the engaging hole 3c of the bottom plate 3a of the lower case 3, engaging holes 3c which fitted the engaging projection portion 9b in the present embodiment, the longitudinal of said plate-shaped heat dissipating member 9 A plurality of LEDs 10 are arranged in the direction, that is, the arrangement direction of the LEDs 10.

In the present embodiment, each of the engaging protrusions 9b is formed in a small pin shape, and the plurality of engaging protrusions 9 are on the lower case 3 side when the plate-like heat radiating member 9 is disposed. The heat radiating member main body 9a is formed in a comb-teeth shape at equal intervals on one side surface in the longitudinal direction. Then, the engagement projections 9b protrudes the plate-shaped heat radiating member 9 when is fitted into the engaging hole 3c so as to be erected on the lower case 3, the tip to the lower case 3 out and is housed in the lower gap of the bottom plate portion 3aa, there is a Isun methods such projects from the lower surface of the bottom plate portion 3ab.

Then, in the present embodiment, fitted causes the pin-like the engaging projection portion 9b on the engagement hole 3c of the corresponding. Thus, the plate-like heat radiating member 9 is erected and fixed to the lower case 3, and from the heat radiating member main body 9 a to the lower case 3 made of aluminum via the pin-like engaging protrusion 9 b. A heat transfer path is formed. The formation position and the number of the engagement protrusions 9b correspond to the formation position and the number of the engagement holes 3c formed in the lower case 3. Further, the specific shape of the pin-shaped engaging projection 9b is not limited to the shape shown in FIGS. 3 and 4, and is fitted so as to be thermally connected in relation to the engaging hole 3c. Any other shape such as a cylindrical shape may be used as long as the shape can be worn .

The liquid crystal display device configured as described above transmits the heat generated by the LED 10 from the one surface side where the LED 10 is disposed to the other surface side which is the back surface by the plate-like heat pipe structure of the heat radiating member main body 9a. The heat is dissipated to the wall opening 6c, and is transmitted from the heat radiating member main body 9a to the lower case 3 to which the engaging protrusion 9b is fitted via the engaging protrusion 9b. Heat can be radiated to the outside, and the same effect as in the first embodiment can be obtained.

  6 to 8 are perspective explanatory views showing a mechanism for fixing the plate-like heat radiating member 9 in the liquid crystal display device 1 in the liquid crystal display device according to the third embodiment of the present invention. Hereinafter, the main part of the present invention different from the first embodiment will be described, and the description of the same components as those of the above-described embodiment will be omitted.

In the liquid crystal display device 1 of the third embodiment, a tongue 3e formed by a U-shaped notch is folded inward of the lower case 3 on the wall 3b located on the light source side of the lower case 3. A plurality of leaf spring portions 3d are formed to bend and act as contact portions, and to act as a biasing member that presses a member that contacts the tongue piece 3e toward the inside of the lower case 3. Further, the formation of the engagement holes 3c and the engagement protrusions 9b of the plate-like heat radiating member 9 formed in the bottom plate portion 3a of the lower case 3 in the above-described two embodiments is arbitrary, and in this embodiment The engagement hole 3c and the engagement protrusion 9b are not formed.

  That is, in the present embodiment, the plate-like heat radiating member 9 is composed only of the heat radiating member main body 9a, and the LED 10 is placed on the surface of the plate-like heat radiating member 9 facing the light guide plate 7 on the light guide plate. A plurality of LEDs 10 are mounted so as to be arranged in the longitudinal direction of the side end surfaces of the No. 7, and a control circuit for controlling lighting of the LEDs 10 is formed.

In the present embodiment, in the lower case 3 of the housing 1, the plate-like heat radiating member 9 is disposed outside the wall portion 6 b where the wall portion opening 6 c of the intermediate case 6 is formed. The LED 10 is disposed so as to face the incident surface 7a of the light guide plate 7 stacked therein, and the tongue piece 3e of the leaf spring portion 3d formed on the wall portion 3b of the lower case 3 is disposed in the plate shape. The intermediate case is pressed against the other end surface of the heat dissipating member 9 on which the LED 10 is disposed, pressing the plate-like heat dissipating member 9 toward the wall portion 3b facing the wall portion 3b of the lower case 3. Hold between 6 and fixed.

The liquid crystal display device configured as described above transmits the heat generated by the LED 10 from the one surface side where the LED 10 is disposed to the other surface side which is the back surface by the plate-like heat pipe structure of the heat radiating member main body 9a. The heat is radiated from the wall surface opening 6c, and is transmitted to the lower case 3 via the leaf spring portion 3d that contacts the other surface of the plate-like heat radiating member 9 including the heat radiating member main body 9a. Therefore, it is possible to obtain the same effects as those of the first and second embodiments described above.

  FIG. 6 shows a case where metal radiating fins 11 for promoting heat radiation are formed on the lower surface of the bottom plate portion 3 a of the lower case 3. This heat radiation fin 11 can be similarly formed in the lower case 3 that acts as a heat radiation mechanism in the first and second embodiments.

  In any of the embodiments, the intermediate case 6 in which the reflection sheet, the light guide plate 7 and the optical sheet are stacked and stored can be omitted. In this case, for example, in the above-described third embodiment, the plate-like heat radiating member 9 is formed with a contact wall that presses the plate-like heat radiating member 9 against the lower case 3, thereby The lower case 3 can be fixedly arranged in a state where the distance between the incident surface 7a and the LED 10 as the light source is kept at a predetermined distance.

  FIG. 9 is a graph for explaining an effect related to the increase in luminance of the liquid crystal display device according to the first embodiment of the present invention. FIG. 9A is a graph showing a high level in a conventional display device to be compared with the present invention. The relationship between the current and temperature of derating (load reduction) performed to maintain the heat-resistant temperature on the chip surface (hereinafter referred to as chip allowable temperature: 120 ° C.) when the LED 10 with current (150 mA) is used. Show. In addition, the vertical axis | shaft of each graph of (a) thru | or (c) is the electric current input into an LED chip, and a horizontal axis | shaft is the ambient temperature (thermosensor installation location temperature) of this LED chip.

  In (a), a high-intensity display is performed by supplying a current of 150 mA until the LED ambient temperature of 60 ° C. is detected, and derating until 85 ° C. is detected after the LED ambient temperature of 60 ° C. is detected. The current was decreased in accordance with the temperature rise), the chip allowable temperature (120 ° C.) was maintained, and the luminance display conforming to the standard was realized.

  On the other hand, in the liquid crystal display device according to the first embodiment of the present invention, as shown in (b), the heat resistance is reduced by the heat dissipation effect, so that the heat loss due to the increase in the LED current is suppressed, and the periphery of the LED Until the temperature of 85 ° C. was detected, a high-luminance display could be realized without derating.

  Further, in the liquid crystal display device according to the first embodiment of the present invention, when the conventional derating shown in (a) from the stage where 60 ° C. is detected until 85 ° C. is detected, as shown in (c). In addition, it was found that a current of 200 mA was allowed to flow until the LED ambient temperature of 60 ° C. was detected, and a current of 150 mA could be allowed to flow until 85 ° C. was detected after the LED ambient temperature of 60 ° C. was detected. Therefore, it has been found that display with higher luminance can be realized or the number of LEDs can be reduced.

  As described above, in the display device having the heat dissipation mechanism of the present invention, the heat dissipation effect of the heat dissipation member main body 9a itself is lowered from the heat dissipation member main body 9a via the shaft portion and the locking head portion of the engaging protrusion 9b. Combined with the heat dissipation effect that is transmitted to the case 3 and radiates heat from the lower case 3 to the outside, it is possible to realize a high-luminance display of the display device.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Upper case 3 Lower case 3c Engagement hole 4 Liquid crystal panel 5 Backlight unit 6 Intermediate case 7 Light guide plate 8 Circuit board 9 Plate-shaped heat radiation member 9a Heat radiation member main body 9b Engagement projection part 9ba Shaft part 9bb Locking Head 10 LED

Claims (4)

The display device includes an upper case and a lower case, and a backlight unit having a light source disposed opposite to a liquid crystal panel, a light guide plate, and a side end surface serving as an incident surface of the light guide plate in the lower case. And
A plate-like heat radiating member having a long heat radiating member main body having a plate-like heat pipe structure, and a plurality of engaging projections formed integrally with the heat radiating member main body and including a shaft portion and a locking head. With
Wherein the light source is formed by a plurality of LED are arranged on one side of the heat dissipation member main body,
The backlight unit includes a rectangular bottom plate portion and an intermediate case that houses the light guide plate, and includes a wall portion standing on the periphery of the bottom plate portion.
The intermediate case has a wall surface opening corresponding to the arrangement length of the LEDs of the light source at the center of the wall portion on the light source side, and the bottom plate portion is continuous with the wall surface opening. The bottom plate opening is formed,
The lower case is configured by a heat radiating portion at least partly made of a highly heat conductive material, and the heat radiating portion is formed with an engagement hole for engaging the engagement protrusion.
The plate-like heat dissipation member, the engaging protrusion is engaged with the engagement hole, Rukoto is engaged said engaging head of the engaging protrusion which projects from the engagement hole in the lower case Thus, the light source is fixed to be opposed to a side end surface that is an incident surface of the light guide plate. The display device includes an upper case and a lower case, and a backlight unit having a light source disposed opposite to a liquid crystal panel, a light guide plate, and a side end surface serving as an incident surface of the light guide plate in the lower case. And
A plate-like heat radiation member having a long heat radiation member main body having a plate-like heat pipe structure and a plurality of pin-like engagement protrusions integrally formed on the heat radiation member main body,
Wherein the light source is formed by a plurality of LED are arranged on one side of the heat dissipation member main body,
The backlight unit includes a rectangular bottom plate portion and an intermediate case that houses the light guide plate, and includes a wall portion standing on the periphery of the bottom plate portion.
The intermediate case has a wall surface opening corresponding to the arrangement length of the LEDs of the light source at the center of the wall portion on the light source side, and the bottom plate portion is continuous with the wall surface opening. The bottom plate opening is formed,
The lower case is constituted by a heat radiating portion at least a part of the bottom plate portion of which is made of a high thermal conductivity material, and the heat radiating portion is formed with an engagement hole for fitting the engagement protrusion , a bottom plate portion of the lower case, the engaging protrusion outwardly from the lower surface of the bottom plate portion of the region in which the tip portion of the engaging protrusion for accommodating the intermediate case when was fitted to the engagement hole In order not to protrude, it is formed in a step shape in which the region in which the engagement hole is formed is positioned higher than the region in which the intermediate case is accommodated,
The plate-like heat dissipation member, by fitting the engaging protrusion in the engaging hole, and is fixed to the light source in the lower case to face the incident surface to become the side end surface of the light guide plate A display device characterized by that. The display device includes an upper case and a lower case, and a backlight unit having a light source disposed opposite to a liquid crystal panel, a light guide plate, and a side end surface serving as an incident surface of the light guide plate in the lower case. And
A plate-like heat radiating member formed with a long heat radiating member body having a plate-like heat pipe structure,
Wherein the light source is formed by a plurality of LED are arranged on one side of the heat dissipation member main body,
The backlight unit includes a rectangular bottom plate portion and an intermediate case that houses the light guide plate, and includes a wall portion standing on the periphery of the bottom plate portion.
The intermediate case has a wall surface opening corresponding to the arrangement length of the LEDs of the light source at the center of the wall portion on the light source side, and the bottom plate portion is continuous with the wall surface opening. The bottom plate opening is formed,
The lower case is made of a rectangular bottom plate portion and the periphery standing wall portion of the bottom plate portion is constituted by a heat radiating portion at least partially made of high thermal conductivity material, the heat radiation member, the lower A contact portion that extends from the wall portion side located on the light source side to the wall portion side facing the wall portion of the case and is brought into contact with the plate-like heat radiating member is cut out, and the plate The radiating member is pressed toward the opposing wall portion of the lower case by the urging force of the contact portion, and is sandwiched between the intermediate case and fixed in the lower case. Display device. The abutting portion is formed in a leaf spring shape, and the abutting portion is brought into contact with the opposite side of the plate-like heat radiating member where the light source is disposed, and the light source is stored in the intermediate case. the display device according to claim 3, characterized in that is opposed to the side end surface serving as has been incident surface of the light guide plate.

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