DE102019205029A1 - Display device with improved thermal management - Google Patents

Abstract

The present invention relates to a display device (1) with improved thermal management. The display device (1) has a display panel (10) and at least one electronic component (12) for the display panel (10), which is arranged adjacent to an active surface (13) of the display panel (10). The display device (1) also has a heat-conducting element (14) which is larger than the at least one electronic component (12) and which is designed to distribute the heat input generated by the electronic component (12) over an area.

Description

The present invention relates to a display device with improved thermal management, in particular with improved cooling of electronic components.

Thermal management in display devices wins in view of a constant increase in the processing power of electronic devices, e.g. the processors of smartphones are becoming increasingly important.

For example, describes WO 2013/049243 A1 an OLED display (OLED: Organic Light Emitting Diode) for a smartphone. The display stack of the OLED display has a thermally conductive layer which is arranged on or under a substrate of the display stack. The thermally conductive layer is used to distribute the heat produced by the electronic components of the smartphone evenly over the OLED display.

However, all display types currently used in display devices heat up significantly with respect to the environment, regardless of the other electronic components, also due to internal losses. The drivers are an essential source of heat in a display. Typically the drivers are mounted on a glass substrate of the display, but they can also be mounted on a circuit board, e.g. a flexible printed circuit board. The number of driver elements can vary. Another source of heat in liquid crystal displays (LCD: Liquid Crystal Display) is the backlighting, e.g. can be implemented in the form of an arrangement of LEDs (LED: Light Emitting Diode; light emitting diode). Due to the concept, the driver components for the backlighting can also lead to additional heat input. Further factors are increasing demands on the resolution and the color saturation of displays, which in turn drive up the power loss of the display.

A strong heat development of the driver components, possibly combined with the heat development of the backlighting, leads to a significant heating of the optical components of the display, e.g. optical foils or polarizing filters. In the worst case, this increase in temperature can lead to damage to the optical components.

Furthermore, a considerable amount of heat develops on the display surface or the glass surface. These hot spots on the glass surface in the area of the driver components are undesirable, especially when using a display with a touch function, or if they are touched they lead to unpleasant effects for the user.

Due to the strong local heating, the brightness may have to be turned down early to protect the materials used and to ensure comfort for the user. Increased brightness requirements of customers and the associated performance input into the system can no longer be achieved without additional measures with the current state of the art.

It is an object of the present invention to provide a display device with improved thermal management.

This object is achieved by a display device with the features of claim 1. Preferred embodiments of the invention are the subject matter of the dependent claims.

• - ein Display-Panel;
• - zumindest ein elektronisches Bauteil für das Display-Panel, das angrenzend an eine aktive Fläche des Display-Panels angeordnet ist; und
• - ein wärmeleitendes Element, das größer als das zumindest eine elektronische Bauteil ist und das dazu ausgebildet ist, einen vom elektronischen Bauteil erzeugten Wärmeeintrag flächig zu verteilen.

According to the invention, a display device has:

• - a display panel;
• - At least one electronic component for the display panel, which is arranged adjacent to an active surface of the display panel; and
• a thermally conductive element which is larger than the at least one electronic component and which is designed to distribute a heat input generated by the electronic component over a large area.

In the solution according to the invention, an additional heat-conducting or heat-distributing element is applied to the heat-producing electronic component. The thermally conductive element is made of a suitable material with a high thermal conductivity, e.g. made of pyrolytic graphite [1]. Due to the large-area application compared to the electronic component, the heat input is distributed more evenly and the temperature on the electronic components is reduced. The resulting improved cooling enables higher power densities to be achieved. In addition, the temperature range in which the display device manages without active cooling is expanded. The solution according to the invention can be used for all types of display applications.

According to one aspect of the invention, the at least one electronic component is a driver or a lighting element. The at least one electronic component can be arranged, for example, on a substrate of the display panel, a circuit board for the display panel or a circuit board of a lighting assembly. Drivers and lighting elements are essential Heat sources that are not already thermally connected in current display devices, so that cooling these components is particularly recommended. However, the solution can also be applied to other components with lost heat that are not in the optical path.

According to one aspect of the invention, the display device has a cover glass for the display panel, the at least one electronic component being arranged below the cover glass. Display devices are often provided with a cover glass, particularly for applications in the automotive sector. Because of the thermally non-conductive glass environment, heat build-up typically occurs without further measures. In this case, heat-producing electronic components arranged below the cover glass can cause hot spots on the glass surface. These are perceived by the user as annoying, especially in displays with a touch function, and should therefore be avoided. Heat dissipation from these electronic components is therefore particularly useful in order to ensure that the display device can be operated comfortably for the user.

According to one aspect of the invention, the heat-conducting element extends over the entire width of the display panel, over the entire rear side of the display panel or over at least part of a housing of the display device. In all of these embodiments, a particularly large-area distribution of the heat input is achieved; the cooling of the electronic components is therefore particularly effective.

According to one aspect of the invention, the heat-conducting element is designed to be flexible. For example, a foil made of pyrolytic graphite, graphene or metal can be used as the thermally conductive element. The flexible configuration allows a largely free adaptation of the heat-conducting element to the geometric conditions of the display device, in particular with regard to the available space. A flexible configuration is also helpful in order to realize a thermal connection of the thermally conductive element to a heat sink. A thermal connection to an external component and the heat transfer to less critical areas of the display device can further increase the cooling. The external component can for example be a housing of the display device.

According to one aspect of the invention, the at least one electronic component is thermally connected to the heat-conducting element. In this way, the heat dissipation is additionally improved, since the heat conduction from the electronic component into the heat-conducting element is increased.

According to one aspect of the invention, the heat-conducting element is arranged on an underside of the substrate. The heat transport from the heat source to the thermally conductive element is dependent on the substrate thickness. This configuration is therefore particularly suitable for thin displays, such as those used e.g. needed for curved displays. At the same time, this arrangement enables more efficient cooling.

According to one aspect of the invention, the thermally conductive element is glued to the cover glass. The use of an adhesive connection significantly simplifies the application of the thermally conductive element. In this configuration, an additional thermal coupling between the thermally conductive element and the electronic component is recommended in order to ensure sufficient heat transport. Alternatively, the thermally conductive element is separated from the cover glass by an air gap or by a thermal insulator. A further reduction in the surface temperature on the front of the display or the cover glass is achieved by thermal decoupling by means of an air gap or a thermal insulator. Here, the heat-conducting element and the thermal insulator can be designed as individual elements or as a combination of two different materials in one assembly. The combination can e.g. be made by lamination.

Further features of the present invention will become apparent from the following description and the appended claims in conjunction with the figures.

Figure list

• 1 shows a perspective illustration of an embodiment of a display device according to the invention with electronic components and a heat-conducting element;
• 2 shows a plan view of an embodiment of a display device according to the invention;
• 3 shows a section through an embodiment of a display device according to the invention;
• 4th shows an embodiment of the display device with thermal coupling between the electronic component and the thermally conductive element;
• 5 shows an embodiment of the display device with thermal decoupling between the thermally conductive element and a cover glass;
• 6th shows a further embodiment of the display device with thermal decoupling between the heat-conducting element and a cover glass;
• 7th shows an embodiment of the display device with connection of the thermally conductive element to a heat sink;
• 8th illustrates an adapted configuration of the heat-conducting element for the embodiment of the display device 7th ;
• 9 shows an embodiment of the display device with cooling of a lighting assembly;
• 10 shows a further embodiment of the display device with cooling of the lighting assembly; and
• 11 shows an embodiment of the display device with a thermally conductive element arranged below a substrate.

Figure description

For a better understanding of the principles of the present invention, embodiments of the invention are explained in more detail below with reference to the figures. The same reference symbols are used in the figures for elements that are the same or have the same effect and are not necessarily described again for each figure. It goes without saying that the invention is not restricted to the illustrated embodiments and that the features described can also be combined or modified without departing from the scope of protection of the invention as defined in the appended claims.

1 shows a perspective view of an embodiment of a display device according to the invention 1 with several electronic components 12 and a thermally conductive element 14th . A perspective exploded drawing of the display device is shown 1 . With the electronic components 12 In this exemplary embodiment, the driver of a display panel is involved 10 that are on a substrate 15th of the display panel 10 adjacent to an active surface shown here in dashed lines 13 are arranged. On the active surface 13 there is a cover 26th , the design and function of which depends on the type of display. In the case of a liquid crystal display, the cover is 26th For example, a color filter glass, but in the case of an OLED display, a cover glass that is required for encapsulation. The active area 13 is typically slightly smaller than the cover 26th . Above the display panel 10 is a cover slip 11 intended. The thermally conductive element 14th extends over the entire width of the display panel 10 and thus over all drivers. By applying a thermally conductive element to the surface 14th Made of a suitable material with a high thermal conductivity, the heat input of the drivers is evenly distributed and the temperature at the drivers is reduced.

2 shows a plan view of an embodiment of a display device according to the invention 1 . In this embodiment, the electronic components are not visible here and are therefore shown in dashed lines 12 not on a substrate of the display panel 10 arranged, but on a circuit board 16 for the display panel 10 . The circuit board 16 for the display electronics, in turn, is adjacent to an active surface 13 of the display panel 10 on. On the circuit board 16 is a thermally conductive element 14th arranged, which as in 1 across the entire width of the display panel 10 and thus over all electronic components on the circuit board 16 extends.

3 shows a section through an embodiment of a display device according to the invention 1 . On a substrate 15th of the display panel 10 is an electronic component 12 arranged, in this case a driver. The driver is adjacent to an active surface for the image display or to a cover located thereon 26th arranged. The display panel 10 is in a housing 2 mounted on the display device. The case 2 is outward through a cover slip 11 completed. The thermally conductive element 14th is in this example on the back of the cover slip 11 under one on the cover slip 11 applied black print 19th appropriate. Between the cover 26th and the cover slip 11 there is a bonding layer 27 . The gap between the adjacent components can also be filled with air.

4th shows an embodiment of the display device 1 with thermal coupling between the electronic component 12 and the thermally conductive element 14th . In this exemplary embodiment, the heat-conducting element is installed 14th on the back of the cover slip 11 , for example by means of an adhesive connection 20th . An adhesive tape can be used particularly advantageously for this purpose. At the same time ensures a back on the thermally conductive element 14th applied thermal coupling 21st reliable heat conduction from the electronic component 12 in the thermally conductive element 14th . The electronic component 12 is in this example on a substrate 15th of the display panel 10 arranged.

5 shows an embodiment of the display device 1 with thermal decoupling between the thermally conductive element 14th and the cover slip 11 . In this embodiment that will thermally conductive element 14th without connection to the cover slip 11 directly onto the electronic component 12 upset. Between that on the substrate 15th arranged electronic component 12 and the thermally conductive element 14th there is a thermal coupling 21st . By means of an air gap 22nd becomes the thermally conductive element 14th thermal from the cover slip 11 decoupled. This results in a further reduction in the surface temperature on the front of the display device 1 or the cover glass 11 reached.

6th shows a further embodiment of the display device 1 with thermal decoupling between the thermally conductive element 14th and the cover slip 11 . In this embodiment too, the thermally conductive element 14th without connection to the cover slip 11 using thermal coupling 21st directly on the electronic components 12 upset. In addition, is on the thermally conductive element 14th a thermal insulator 18th upset. Through thermal decoupling by means of a thermal isolator 18th is a further reduction in the surface temperature on the front of the display device 1 or the cover glass 11 achieved. Here, the thermally conductive element 14th and the thermal insulator 18th be designed as individual elements or as a combination of two different materials in one assembly. The combination can be produced, for example, by lamination. Between the thermal isolator 18th and the cover slip 11 can, as in 6th recognizable, an additional air gap 22nd be provided. The electronic component 12 is like before on the substrate 15th of the display panel 10 arranged.

7th shows an embodiment of the display device 1 with connection of the thermally conductive element 14th to a heat sink 17th . In this example, the heat sink is part of a housing 2 the display device 1 . As before, the thermally conductive element 14th without connection to the cover slip 11 using thermal coupling 21st directly on the electronic components 12 upset. By means of an air gap 22nd or alternatively a thermal insulator becomes the thermally conductive element 14th thermal from the cover slip 11 decoupled. Especially when using a flexible thermally conductive element 14th , for example a thermally conductive film, the cooling can be achieved through a thermal connection to an external component 2 and the heat transport into less critical areas of the display device 1 To this end, an application-specific adaptation of the shape of the heat-conducting element may be necessary 14th makes sense. This can be done in a simple manner by cutting, for example. 8th illustrates such an adapted configuration of the thermally conductive element 14th that are the shape of a circuit board 16 for the display panel 10 considered.

9 shows an embodiment of the display device 1 with cooling of a lighting assembly 23 , which in this example is used for backlighting in the form of an “edge backlight”. The electronic component 12 in this case is a lighting element, in particular an LED component, on a circuit board 24 below the cover slip 11 is arranged and light in a light guide 25th coupled with a stack of foils. By means of a thermally conductive element 14th , for example a thermally conductive film, is applied locally by the lighting assembly 23 Generated heat input over the entire rear of the display panel 10 distributed. This can be done with or without an additional thermal coupling with the surrounding housing 2 implemented as an additional heat sink in the case of thermal coupling 17th serves.

10 shows a further embodiment of the display device 1 with cooling of the lighting assembly 23 . By means of a thermally conductive element 14th is done locally by the lighting assembly 23 generated heat input in this embodiment from the display device 1 transported out and flat on the entire back of a housing 2 the display device 1 distributed. This can in turn with or without an additional thermal coupling with the surrounding housing 2 implemented as an additional heat sink in the case of thermal coupling 17th serves.

11 shows an embodiment of the display device 1 with one below a substrate 15th of the display panel 10 arranged thermally conductive element 14th , ie the thermally conductive element 14th is on the back of the display panel 10 appropriate. The heat transfer from the source to the thermally conductive element 14th depends on the thickness of the substrate 15th so that this variant is particularly suitable for thin displays, such as those required for curved displays. An advantage of this arrangement is that more efficient cooling can be made possible.

credentials

1. [1] Thermal Protection Sheet:
   • https://industrial.panasonic.com/ww/products/thermal-solutions/graphite-she et-pgs / pgs

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 2013/049243 A1 [0003]

Claims (10)

Display device (1) with: - a display panel (10); - At least one electronic component (12) for the display panel (10), which is arranged adjacent to an active surface (13) of the display panel (10); and - A thermally conductive element (14) which is larger than the at least one electronic component (12) and which is designed to distribute a heat input generated by the electronic component (12) over an area. Display device (1) according to Claim 1 , wherein the at least one electronic component (12) is a driver or a lighting element. Display device (1) according to Claim 1 or 2 with a cover glass (11) for the display panel (10), the at least one electronic component (12) being arranged below the cover glass (11). Display device (1) according to one of the preceding claims, wherein the heat-conducting element (14) extends over the entire width of the display panel (10), over the entire rear side of the display panel (10) or over at least part of a housing (2 ) the display device (1) extends. Display device (1) according to one of the preceding claims, wherein the heat-conducting element (14) is designed to be flexible. Display device (1) according to one of the preceding claims, wherein the heat-conducting element (14) is thermally connected to a heat sink (17). Display device (1) according to one of the preceding claims, wherein the at least one electronic component (12) is thermally connected to the heat-conducting element (14). Display device (1) according to one of the preceding claims, wherein the at least one electronic component (12) on a substrate (15) of the display panel (10), a circuit board (16) for the display panel (10) or a circuit board ( 24) a lighting assembly (23) is arranged. Display device (1) according to Claim 8 , wherein the thermally conductive element (14) is arranged on an underside of the substrate (15). Display device (1) according to Claim 8 , wherein the thermally conductive element (14) is glued to the cover glass (11) or is separated from the cover glass (11) by an air gap or by a thermal insulator (18).

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