JP2022132707A - Display device - Google Patents

Abstract

To provide a display device with which the luminance unevenness of a display panel is made to be unnoticeable and display quality is enhanced by reducing a temperature gradient near the boundary of a heat source substrate arranged at the rear of the display panel.SOLUTION: The display device comprises: a display panel 12 for displaying an image; a first circuit board 24 disposed on an edge side at the rear of the display panel; a second circuit board 28 having a heat generation source located closer to the edge side of the display panel than the first circuit board; a heat sink 40 disposed at a position on the rear surface of the display panel that is different from the position where the first and the second circuit boards are disposed; and an adhesive layer 50 provided between the rear surface of the display panel and a portion of the heat sink. The occupancy ratio of the adhesive layer between the rear surface of the display panel and the heat sink is progressively smaller toward the direction of the second circuit board.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to display devices.

For example, in a display device having a display panel such as an organic EL panel, the display quality of the display device may be degraded due to changes in the characteristics of the display panel due to an increase in the temperature of the display panel. Therefore, in the display device of Patent Document 1, the back cover is joined to the back surface of the display panel, and the back cover covers substantially the entire back surface of the display panel.

In the display device of Patent Literature 1, a first circuit board for controlling the display of the display panel is arranged on the rear end side of the back cover. A second circuit board is connected between the display panel and the first circuit board, and the second circuit board has a driving IC for driving the display panel. A drive IC, which is a heat source, is in thermal contact with a support frame, which is a heat radiating member.

WO2020/017210

By the way, the display panel may be delivered from the panel maker in a state where the first circuit board is joined to the back surface of the display panel. In such a case, when the display device is assembled, the back cover is located on the opposite side of the display panel from the first circuit board on the back side of the display panel, and is a heat source. It is not possible to sufficiently dissipate the heat around the first circuit board that is transferred from the drive IC. As a result, the temperature difference between the end portion side and the other portion of the display panel becomes large, and the brightness unevenness of the display panel becomes conspicuous, resulting in deterioration of the display quality of the display device.

Therefore, in view of the above problem, the present disclosure improves the display quality of the display device by reducing the temperature gradient near the boundary of the heat source substrate arranged on the back surface of the display panel, thereby making the luminance unevenness of the display panel inconspicuous. for the purpose.

A display device according to an aspect of the present disclosure includes: a display panel that displays an image; A second circuit board having a heat source located on an end side, and a heat sink disposed at a position different from a position on the rear surface of the display panel on which the first circuit board and the second circuit board are disposed. and an adhesive layer provided between the back surface of the display panel and a portion of the heat sink, wherein the occupancy of the adhesive layer between the back surface of the display panel and the heat sink is equal to the second circuit. It is characterized in that it becomes smaller in the direction of the substrate.

As described above, according to the present disclosure, it is possible to improve the display quality of the display device by reducing the temperature gradient near the boundary of the heat source substrate arranged on the back surface of the display panel, making the luminance unevenness of the display panel inconspicuous. can be done.

1 is a front view of a display device according to a first embodiment of the present disclosure; FIG. FIG. 2 is a front view schematically showing an adhesive layer included in the display device according to the first embodiment of the present disclosure; FIG. FIG. 3 is an enlarged view of part A in FIG. 4 is an enlarged cross-sectional view taken along line BB in FIG. 3. FIG. FIG. 5 is an enlarged cross-sectional view along line CC in FIG. FIG. 6 is a diagram showing the temperature distribution of the surface on the bottom side of the display panel of the display device of the reference example. FIG. 7 is a diagram showing the temperature distribution of the surface on the bottom side of the display panel of the display device according to the first embodiment of the present disclosure. FIG. 8 is a diagram showing temperature changes in a vertical cross section of the display panel in the left-right central portion of the display device according to the first embodiment of the present disclosure. FIG. 9 is a diagram showing the neighborhood where the occupancy rate of the adhesive layer changes. FIG. 10 is a front view schematically showing a modification of the adhesive layer provided in the first embodiment of the present disclosure; FIG. 11 is a front view schematically showing an adhesive layer provided in the second embodiment of the present disclosure; FIG. 12 is a diagram showing the temperature distribution of the surface on the bottom side of the display panel of the display device according to the second embodiment of the present disclosure. FIG. 13 is a diagram showing the temperature distribution of the surface on the bottom side of the display panel of the display device according to the second embodiment of the present disclosure.

Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. As shown in the drawing, one side in the width direction of the display device 10 is on the left side, the other side in the width direction of the display device 10 is on the right side, one side in the height direction of the display device 10 is on the top side, and the height direction of the display device 10 is is referred to as the lower side. In addition, the present embodiment described below does not unduly limit the content of the present disclosure described in the claims, and all of the configurations described in the present embodiment are essential as a solution to the present disclosure. not necessarily.

[First embodiment]
A display device 10 according to the first embodiment includes a display panel 12 , a first circuit board, a second circuit board, a radiator plate 40 and an adhesive layer 50 . First, the overall configuration of the display device 10 will be described.

FIG. 1 is a front view of a display device 10 according to Embodiment 1 of the present disclosure. As shown in FIG. 1, a display device 10 according to Embodiment 1 of the present disclosure is incorporated as a display panel module into, for example, a television receiver, a monitor display, or other equipment. The display device 10 includes a rectangular display panel 12 that displays an image, and the display panel 12 extends in the horizontal direction. The display panel 12 is a self-luminous display panel, specifically an organic EL panel using organic light emitting diode elements. In other words, the display device 10 is a display panel module (OLED module) including an organic EL panel. The display panel 12, which is an organic EL panel, has an EL substrate, a CF substrate (glass substrate) on which color filters are formed, and a resin layer disposed between the EL substrate and the CF substrate. , detailed illustrations and descriptions of these elements are omitted.

The display device 10 includes a rectangular frame 14 that surrounds and holds the display panel 12. The frame 14 is made of metal with high thermal conductivity, such as aluminum or iron.

As shown in FIG. 1, a source board 24 for controlling the display of the display panel 12 is arranged as a first circuit board on the end side of the rear surface of the display panel 12 . The source substrate 24 extends in the left-right direction and is joined to the rear surface of the display panel 12 by a fixing member (joining member) 26 such as double-sided tape. The source substrate 24 is a printed circuit board on which electronic components (not shown) such as capacitors, resistors, and diodes are mounted.

Further, as shown in FIG. 1, a plurality of flexible substrates 28 as second circuit substrates are arranged at intervals in the left-right direction on the back side of the display panel 12 . As shown in FIG. 5, the flexible board 28 is positioned closer to the end of the display panel 12 than the first circuit board. Each flexible substrate 28 is a connection substrate that connects the display panel 12 and the source substrate 24 . A first connection terminal (not shown) for connecting to the display panel 12 is formed on one end side of each flexible substrate 28 . A second connection terminal (not shown) for connecting to the source substrate 24 is formed on the other end side of each flexible substrate 28 . Each flexible board 28 has a source driver 30 for driving the display panel 12 . Each source driver 30 is positioned on the bottom side (lower end side) of the display panel 12 relative to the source substrate 24 and supplies drive signals for driving the display panel 12 to the display panel 12 . Each source driver 30 becomes a heat source during operation of the display device 10 . The plurality of source drivers 30 are arranged at intervals in the horizontal direction (width direction). Each source driver 30 that is a heat source transfers heat to the source substrate 24 .

A heat insulating member 32 is provided between the back surface of the display panel 12 and each source driver 30 . The plurality of heat insulating members 32 are arranged at intervals in the left-right direction, similar to the plurality of source drivers 30 . Each heat insulating member 32 is made of a porous material such as highly expanded silicon foam or polyurethane foam.

Here, since the second circuit board has the source driver 30 , it becomes a heat source, and the heat of the source driver 30 is transmitted to the source substrate 24 and then to the display panel 12 . The heat is radiated from the radiator plate 40 at the portion where the source driver 30 and the source substrate 24 are not provided on the back side of the display panel 12 . Then, a large temperature gradient occurs between the surface of the display panel 12 where the source driver 30 and the source substrate 24 are provided and the surface of the display panel 12 where the heat sink 40 is provided, resulting in uneven luminance. is conspicuous. Therefore, an adhesive layer 50 is provided between the back surface of the display panel 12 and a part of the heat sink 40, and the occupancy of the adhesive layer 50 is reduced toward the second circuit board, so that the display can be improved. The temperature uniformity of the entire panel 12 can be achieved, and the uneven brightness of the display panel 12 can be made inconspicuous, thereby improving the display quality of the display device. The display device 10 according to the first embodiment will be described in detail below.

FIG. 2 is a front view schematically showing the adhesive layer 50 included in the display device 10 according to the first embodiment of the present disclosure. The adhesive layer 50 shown in FIG. 2 is provided on the rear surface of the display panel 12 and part of the heat sink 40 as shown in FIGS. 3-5. As shown in FIG. 3-5, the occupation ratio of the adhesive layer 50 between the rear surface of the display panel 12 and the heat sink 40 is characterized by decreasing in the direction in which it is arranged on the second circuit board. .

As shown in FIG. 3, there are portions where a portion of the adhesive layer 50 extends to the vicinity of the source substrate 24 and portions where it does not extend. Also, on the rear surface of the display panel 12 , the occupation ratio of the adhesive layer 50 decreases toward the flexible substrate 28 .

Details thereof will be described with reference to cross-sectional views. 4 is an enlarged cross-sectional view taken along line BB in FIG. 3. FIG. 5 is an enlarged cross-sectional view taken along line CC in FIG. 4, the adhesive layer 50 extends to the vicinity of the source substrate 24 (first circuit substrate) toward the flexible substrate 28 (second circuit substrate), but in FIG. (the second circuit board) and does not extend to the vicinity of the source substrate 24 (the first circuit board). That is, the non-adhesive layer region S exists between the display panel 12 and the heat sink 40 . In this way, the occupation ratio of the adhesive layer 50 between the rear surface of the display panel 12 and the heat sink 40 decreases toward the second circuit board.

In the region where the adhesive layer 50 and the heat sink 40 are provided, the heat of the source substrate 24 transmitted from the source driver 30 is easily released by the heat sink 40, and the surface temperature of the display panel 12 decreases. In the area where the plate 40 is not provided, the heat cannot be radiated by the heat sink 40, so the temperature of the surface of the display panel 12 becomes high. Therefore, the temperature difference between the area where the heat sink 40 is provided and the area where the heat sink 40 is not provided on the surface of the display panel 12 increases.

Therefore, by providing a non-adhesive layer region S between the display panel 12 and the heat sink 40 and decreasing the occupancy rate of the adhesive layer 50 toward the second circuit board, the area where the heat sink 40 is provided is reduced. However, the non-adhesive layer region S can reduce the heat radiation from the heat sink 40, and reduce the temperature difference between the region where the heat sink 40 is provided and the region where the heat sink 40 is not provided. can do. In this way, the display device 10 according to the first embodiment can efficiently equalize the temperature of the entire display panel 12, make the luminance unevenness of the display panel 12 inconspicuous, and further improve the display quality of the display device. can.

As shown in FIG. 2, the adhesive layer 50 preferably has a plurality of projections 51 on the second circuit board side. In this way, the temperature of the entire display panel 12 can be efficiently uniformed, and the uneven brightness of the display panel 12 can be made less conspicuous, thereby further enhancing the display quality of the display device. Also, the length L of the projection 51 shown in FIG. 2 is preferably 1 cm to 10 cm, more preferably 3 cm to 7 cm. If it is less than 1 cm, the non-adhesive layer region S becomes small, and the effect of uniformizing the temperature of the entire display panel 12 tends to be small. On the other hand, if the length is larger than 10 cm, the adhesion with the heat sink 40 becomes weak, and it tends to be difficult to sufficiently attach the heat sink 40 to the display panel 12 .

Further, it is conceptually conceivable to change the thickness of the adhesive layer 50 in the vertical direction of the display panel 12, but preparing the adhesive layer 50 with different thicknesses is difficult in terms of manufacturing. Therefore, according to the display device 10 according to the first embodiment, the occupation ratio of the adhesive layer is decreased toward the second circuit board, so that the temperature gradient on the surface of the display panel 12 can be decreased. , and can be easily manufactured.

The adhesive layer 50 is preferably an adhesive tape. By doing so, the display panel 12 and the heat sink 40 can be easily attached.

A thermally conductive material may be mixed into the adhesive layer 50 . Also, the content of the thermally conductive material mixed in the adhesive layer 50 may be increased toward the upper surface of the display panel 12 . In this way, the temperature gradient can be further reduced even within the area where the heat sink 40 is provided.

Note that the adhesive layer 50 may be a printed matter described later instead of the adhesive tape. In this case, the adhesive layer 50 may be formed by screen printing or the like.

FIG. 6 is a diagram showing the temperature distribution of the surface on the bottom side of the display panel 12 of the display device of the reference example. 6 does not have the protrusion 51 of the adhesive layer 50 as shown in FIG. 2, and does not have the non-adhesive layer region S as shown in FIG. Further, as the configuration of the display device of the reference example in FIG. 6, the cross-sectional views taken along line BB and line CC in FIG. 3 are both configured as shown in FIG. It exists up to the vicinity of the substrate 24 . FIG. 7 is a diagram showing the temperature distribution of the surface on the bottom side of the display panel 12 of the display device 10 according to the first embodiment of the present disclosure.

As shown in FIG. 6, in the display device of the reference example, since there is no non-adhesive layer region S, the heat of the source substrate 24 (first circuit substrate) transmitted from the source driver 30 is radiated steeply from the edge portion of the radiator plate. Therefore, it can be seen that the temperature gradient on the bottom surface side of the display panel 12 in the circled portion is large.

On the other hand, as shown in FIG. 7, in the display device 10 according to the first embodiment of the present disclosure, the heat of the source substrate 24 (first circuit substrate) transmitted from the source driver 30 can be gradually dissipated. It can be seen that the temperature gradient on the bottom surface side of the display panel 12 is small.

FIG. 8 is a diagram showing temperature changes in a vertical cross section of the left-right central portion of the display panel 12 of the display device 10 according to the first embodiment of the present disclosure. FIG. 9 is a diagram showing the neighborhood where the occupancy rate of the adhesive layer 50 changes. That is, in FIG. 8, it is a diagram showing changes in temperature from -0.35 to -0.25 m in the vertical direction. A solid line indicates the temperature change of the display panel 12 of the display device 10 according to the first embodiment. On the other hand, the dotted line indicates the temperature change of the display panel of the display device of the reference example.

In FIG. 8, the source driver 30 is positioned behind the display panel 12 at the coordinates with the highest temperature. Then, the temperature decreases from the source driver 30 toward the upper surface of the display panel 12 . As shown in FIGS. 8 and 9, in the display panel 12 of the display device of the reference example, the temperature change from the source driver 30 toward the upper surface of the display panel 12 is large. On the other hand, in the display panel 12 of the display device 10 according to the first embodiment, it can be seen that the temperature change from the source driver 30 toward the upper surface of the display panel 12 is small.

As described above, in the display device 10 according to the first embodiment of the present disclosure, the temperature of the entire display panel 12 can be uniformed, the luminance unevenness of the display panel 12 can be made inconspicuous, and the display quality of the display device can be improved.

FIG. 10 is a front view schematically showing a modification of the adhesive layer 50 provided in the first embodiment of the present disclosure. As shown in FIG. 10, the tips of the projections 51 of the adhesive layer 52 are preferably rounded. In this way, the display panel 12 and the radiator plate 40 are less likely to peel off, the temperature of the entire display panel 12 is uniformed, the luminance unevenness of the display panel 12 is made inconspicuous, and the display quality of the display device is further improved. can be done.

The second circuit board may be arranged on the bottom side of the display panel 12 . Heat is easily transferred to the top side of the display panel 12, but since the convection phenomenon of air is not developed on the bottom side of the display panel 12, heat transfer is predominantly due to heat conduction. Since the ratio between the layer 52 and the non-adhesive layer region S gradually changes, the thermal conductivity also gradually changes, and the temperature of the entire display panel 12 is uniformed, and the luminance unevenness of the display panel 12 is made inconspicuous. display quality can be improved.

As described above, in the display device 10 according to the first embodiment of the present disclosure, the display quality of the display device can be improved by uniforming the temperature of the entire display panel 12 and making the luminance unevenness of the display panel 12 inconspicuous. .

[Second embodiment]
Next, a second embodiment will be described. FIG. 11 is a front view schematically showing an adhesive layer 53 provided in the second embodiment of the present disclosure. As shown in FIG. 11, the adhesive layer 53 has an adhesive layer main body 54 and dots 55, and the dots 55 are provided so as to become smaller toward the second circuit board side. The second embodiment is characterized by having dots 55 on the adhesive layer 53 . The occupation ratio of the adhesive layer 53 provided in the second embodiment of the present disclosure also decreases toward the second circuit board, like the adhesive layer 53 provided in the second embodiment. Note that the adhesive layer body 54 is rectangular.

In this way, the occupancy rate of the adhesive layer 53 between the back surface of the display panel 12 and the heat sink 40 can be gradually reduced toward the second circuit board, and the temperature of the entire display panel 12 can be uniformed. The display quality of the display device can be further improved by making the luminance unevenness of the display panel 12 inconspicuous.

The adhesive layer 53 is preferably a printed matter. Since the dot 55 shape is separated from each other by one point, the adhesive layer 53 can be easily formed in this way.

FIG. 12 is a diagram showing the temperature distribution of the surface on the bottom side of the display panel of the display device according to the second embodiment of the present disclosure. It can be seen that in the display device according to the second embodiment of the present disclosure, the heat of the source substrate (first circuit substrate) transmitted from the source driver can be released slowly, and the temperature gradient on the bottom surface side of the display panel is small.

FIG. 13 is a diagram showing the temperature distribution of the surface on the bottom side of the display panel of the display device according to the second embodiment of the present disclosure. As shown in FIG. 13, in the display panel of the display device according to the second embodiment, it can be seen that the temperature change from the source driver toward the upper surface of the display panel is smaller than that of the display panel of the display device of the reference example. .

As described above, in the display device according to the second embodiment of the present disclosure, the temperature gradient near the boundary of the heat source substrate arranged on the back surface of the display panel is reduced, and the luminance unevenness of the display panel is made inconspicuous. display quality can be improved.

Although the embodiments and examples of the present disclosure have been described in detail as described above, it should be understood by those skilled in the art that many modifications are possible without substantially departing from the novel matters and effects of the present disclosure. , will be easily understood. Accordingly, all such modifications are intended to be included within the scope of this disclosure.

For example, a term described at least once in the specification or drawings together with a different, broader or synonymous term can be replaced with the different term anywhere in the specification or drawings. Also, the configuration and operation of the display device are not limited to those described in the embodiments and examples of the present disclosure, and various modifications are possible.

REFERENCE SIGNS LIST 10 display device 12 display panel 14 frame 24 source substrate (first circuit substrate) 26 fixing member 28 flexible substrate (second circuit substrate) 30 source driver (heat source) 32 heat insulating member 40 radiator plate , 50, 52, 53 adhesive layer, 51 protrusion, 54 adhesive layer main body, 55 dot, L length of protrusion, S non-adhesive layer region

Claims (9)

a display panel for displaying an image;
a first circuit board disposed on an end side of the back surface of the display panel;
a second circuit board having a heat source positioned closer to the end of the display panel than the first circuit board;
a radiator plate disposed at a position different from a position on the rear surface of the display panel on which the first circuit board and the second circuit board are disposed;
an adhesive layer provided between the back surface of the display panel and a portion of the heat sink;
with
A display device, wherein the occupation ratio of the adhesive layer between the back surface of the display panel and the radiator plate decreases toward the second circuit board. 2. The display device according to claim 1, wherein the adhesive layer has a plurality of protrusions on the second circuit board side. 3. The display device according to claim 2, wherein the tips of the protrusions are rounded. 4. The display device according to claim 1, wherein the adhesive layer is an adhesive tape. The adhesive layer has an adhesive layer main body and dots,
2. The display device according to claim 1, wherein the dots are provided so as to become smaller toward the second circuit board. 6. The display device according to claim 4, wherein the adhesive layer is a printed matter. 7. The display device according to claim 1, wherein the second circuit board is arranged on the bottom side of the display panel. The first circuit board is a source board that controls display on the display panel, the second circuit board is a connection board that connects the first circuit board and the display panel, and the heat source is the 8. The display device according to claim 1, wherein the display device is a source driver for driving a display panel. 9. The display device according to claim 1, wherein the display panel is an organic EL panel using organic light emitting diode elements.

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