Detailed Description
Referring to fig. 1, a display panel 1 of the present application is used for displaying an image, and is a self-luminous display panel including a plurality of light emitting elements. The application discloses display panel 1 can be an independent device that is used for showing the image, also can be integrated in an intelligent equipment, realizes the function of showing the image as a functional module. The specific shape of the display panel 1 is not limited in this application. The following embodiment exemplifies the case where the plane of the display panel 1 is substantially circular.
Referring to fig. 1 and fig. 2, in the present embodiment, the display panel 1 includes a circuit board 10. The circuit board 10 may be a single layer, a double layer, a triple layer or a multiple layer. The circuit board 10 may be rigid or flexible. The present application is not limited to the configuration or type of circuit board 10. A driving circuit (not shown) is integrated in the circuit board 10 for outputting a plurality of driving signals.
In this embodiment, the display panel 1 further includes a driving chip 20 and a flexible board 30. The driving chip 20 is located on the flexible board 30 and electrically connected to the flexible board 30. The driving chip 20 is used to provide image data including, for example, a gray scale value for each pixel, and the like. The circuit board 10 may also be electrically connected to the driving chip 20 by electrically connecting the flexible board 30, thereby acquiring image data. The plurality of driving signals are generated from the image data.
In the present embodiment, the planar structure of the circuit board 10 is also substantially circular in the view of fig. 1, corresponding to the circular shape of the display panel 1.
In this embodiment, the circuit board 10 includes a first surface 11. The display panel 1 further includes a plurality of light emitting elements 40. The light emitting elements 40 are disposed on the first surface 11 of the circuit board 10 and spaced apart from each other. Each light emitting element 40 is electrically connected to a driving circuit on the circuit board 10. Each of the light emitting elements 40 is configured to receive a driving signal and emit image light according to the driving signal.
In this embodiment, the display panel 1 defines a plurality of sub-pixel regions. One light emitting element 40 is provided in each sub-pixel region. The adjacent three sub-pixel regions constitute one pixel. The light emitting elements 40 in the three sub-pixel regions in the same pixel are used to emit light of different colors, for example, red, green and blue, respectively. In this embodiment, the driving circuit includes at least a plurality of driving elements (e.g., thin film transistors). Each driving element is electrically connected to a light emitting element 40 to output one of the driving signals to drive the light emitting element 40 to emit light. The image to be displayed can be modulated by adjusting the light emission luminance of the light emitting elements 40 in the respective sub-pixels by the drive signals output from the respective drive elements.
In one display period, the circuit board 10 receives image data of one frame of image, generates a plurality of driving signals according to the image data to drive each light emitting element 40 respectively, and the light emitting elements 40 emit image light according to the driving signals received respectively, so that all the light emitting elements 40 display one frame of image in common.
In the present embodiment, each light emitting element 40 is a mini-LED (75-300 microns in size, inclusive). In other embodiments, each light emitting element 40 may also be a Micro light emitting diode (Micro-LED) (with a size less than 75 μm).
In this embodiment, the display panel 1 further includes a thermal isolation layer 50 on the first surface 11 of the circuit board 10. The thermally conductive isolation layer 50 fills the gaps between the individual light emitting elements 40. The thermally conductive, insulative layer 50 is in direct contact with the sides of the respective light emitting elements 40 to partially encapsulate each light emitting element 40. The surface of each light emitting element 40 remote from the circuit board 10 is exposed to the thermally conductive isolation layer 50 to emit image light. In this embodiment, after a plurality of light emitting elements 40 are formed on the circuit board 10, the gaps between the light emitting elements 40 are filled by dispensing to form the thermal conductive isolation layer 50 on the circuit board 10.
In this embodiment, the thermal isolation layer 50 covers all areas of the first surface 11 where the light emitting elements 40 are not disposed. In the present embodiment, the thermal isolation layer 50 is an insulating material, which is electrically insulated from each light emitting element 40 and the circuit board 10.
The thermally conductive isolation layer 50 is made of an opaque material to isolate the image light emitted by the adjacent light emitting elements 40, so as to prevent the image light emitted by different light emitting elements 40 from crosstalk and causing image distortion. The thermal isolation layer 50 is also made of a material with good thermal conductivity, so that heat generated by each light emitting element 40 is conducted out to the air, thereby facilitating heat dissipation of the display panel 1. In this embodiment, the thermally conductive isolation layer 50 may include black ink and a thermally conductive material doped in the ink. The heat conducting material is, for example, one or any combination of silicon, boron nitride, aluminum nitride and diamond. In other embodiments, the thermal isolation layer 50 may also be an opaque thermal conductive adhesive, so that the thermal conductivity is greater than or equal to 2W/mK, and the resistivity is greater than or equal to 108 Ω/m, so as to achieve a good heat dissipation effect.
In this embodiment, the display panel 1 further includes a first heat conductive layer 60 on the first surface 11 of the circuit board 10. The first thermally conductive layer 60 is completely covered by the thermally conductive isolation layer 50. That is, the first thermally conductive layer 60 is located between the circuit board 10 and the thermally conductive isolation layer 50. And the first thermally conductive layer 60 is also in direct contact with the first surface 11 and the thermally conductive, insulating layer 50, respectively. The first heat conductive layer 60 is electrically insulated from the circuit board 10 and each light emitting element 40. The thermally conductive isolation layer 50 conducts heat from the individual light emitting elements 40 and into the first thermally conductive layer 60. The first heat conducting layer 60 is used in conjunction with the heat conducting isolation layer 50 to conduct heat generated by the respective light emitting elements 40 out to the air.
Referring to fig. 2 and 3, in the present embodiment, the first heat conduction layer 60 has a circular ring shape in accordance with the circular shape of the circuit board 10. Since the traces of the driving circuit integrated on the circuit board 10 are generally located at the center of the first surface 11 to be electrically connected to each light emitting element 40, the first heat conductive layer 60 in this embodiment is located at the peripheral region of the first surface 11 to avoid the traces of the driving circuit. That is, the first heat conductive layer 60 in the present embodiment surrounds each light emitting element 40.
When the layout of the traces of the driving circuit is changed, the shape and structure of the first heat conductive layer 60 are also changed accordingly. Referring to fig. 4, in other embodiments, for convenience of routing layout, the first heat conduction layer 60 may further include a plurality of heat conduction blocks 61 disposed at intervals. Each of the heat-conducting blocks 61 is completely covered by the heat-conducting isolating layer 50, that is, each of the heat-conducting blocks 61 is located between the circuit board 10 and the heat-conducting isolating layer 50 and directly contacts the first surface 11 and the heat-conducting isolating layer 50, respectively. Each of the heat conductive blocks 61 is electrically insulated from the circuit board 10 and each of the light emitting elements 40, and is used together with the heat conductive isolation layer 50 to conduct heat generated by the respective light emitting elements 40 to the air. The shape and structure of each heat-conducting block 61 may be the same or different. In this embodiment, the respective heat-conducting blocks 61 are also located at the periphery of the first surface 11, i.e., the periphery of the respective light-emitting elements.
By splitting the first heat conduction layer 60 into the plurality of separated heat conduction blocks 61, the distribution of the first heat conduction layer 60 is more flexible, which is beneficial to avoiding the wiring on the circuit board 10 under the condition of complex wiring and is beneficial to more fully utilizing the space on the first surface 11 of the circuit board 10.
The larger the surface area of the first conductive layer 60, the better the heat dissipation. In other embodiments, the first heat conducting layer 60 may be located at the center of the first surface 11 without interfering with the normal operation of the light emitting element 40.
Referring to fig. 2, in the present embodiment, the circuit board 10 further includes a second surface 12 disposed opposite to the first surface 11. The circuit board 10 further has a plurality of through holes 13 disposed at intervals, and each through hole 13 penetrates through the first surface 11 and the second surface 12. The number of the through holes 13 is not limited in the present application. In the present embodiment, each through hole 13 is also opened on the periphery of the circuit board 10, depending on the position of the first heat conduction layer 60. In the present embodiment, each through hole 13 is a circular through hole, that is, each through hole 13 penetrates through the first surface 11 and the second surface 12 to form a circular opening on the first surface 11 and the second surface 12, respectively. In other embodiments, each through hole 13 may also be a rectangular through hole (i.e., each through hole 13 forms a rectangular opening on the first surface 11 and the second surface 12 when penetrating through the first surface 11 and the second surface 12), a ring-shaped through hole (i.e., each through hole 13 forms a ring-shaped opening on the first surface 11 and the second surface 12 when penetrating through the first surface 11 and the second surface 12), and so on. The shape of the through-hole 13 is not limited in the present application.
The display panel 1 further comprises a second thermally conductive layer 70 located on the second surface 12 of the circuit board 10 and in direct contact with the second surface 12. The second thermally conductive layer 70 also extends from the second surface of the circuit board 10 along each of the vias 13 to the first surface 11 for connection to the first thermally conductive layer 60. The thermally conductive isolation layer 50 conducts heat generated by each light emitting element 40 to the first thermally conductive layer 60, and the first thermally conductive layer 60 in turn conducts heat generated by each light emitting element 40 to the second thermally conductive layer 70. In this embodiment, therefore, the thermally conductive isolation layer 50, the first thermally conductive layer 60, and the second thermally conductive layer 70 are used to collectively conduct heat generated by the light emitting elements 40 out to the air.
The first conductive layer 60 and the second conductive layer 70 are preferably made of a material having good thermal conductivity. In this embodiment, the first thermally conductive layer 60 and the second thermally conductive layer 70 are made of the same material and are both made of metal, such as copper. In other embodiments, the first thermally conductive layer 60 and the second thermally conductive layer 70 may be formed of different materials.
The present application does not limit the shape or configuration of the second thermally conductive layer 70. The larger the surface area of the second thermally conductive layer 70, the better the heat dissipation. In this embodiment, in order to maximize the surface area of the second heat conducting layer 70 to facilitate heat dissipation, the second heat conducting layer 70 almost completely covers the second surface 12 (as shown in fig. 5). That is, the area of the second heat conductive layer 70 is slightly smaller than the area of the second surface 12.
In the display panel 1 of the embodiment, the heat conductive isolation layer 50 is arranged to fill the gaps between the light emitting elements 40 and is made of an opaque material, so that the image light emitted by each light emitting element 40 can be blocked, and the image light emitted by different light emitting elements can be prevented from crosstalk with each other, thereby causing image display distortion. The heat-conducting isolation layer 50 is also selected from heat-conducting materials with better heat-conducting performance, and can conduct heat generated by the light-emitting elements 40 arranged densely to the air, so that the heat-conducting isolation layer 50 is also beneficial to heat dissipation of the display panel 1, and therefore, each light-emitting element 40 in the display panel 1 can work normally, and the service life of each light-emitting element 40 is prolonged. And the display panel 1 further comprises a first heat conducting layer 60 and a second heat conducting layer 70, the first heat conducting layer 60 directly contacting the heat conducting isolating layer 50, the first heat conducting layer 60 being connected to the second heat conducting layer 70. The thermally conductive isolation layer 50 conducts heat generated by each light emitting element 40 to the first thermally conductive layer 60, and the first thermally conductive layer 60 in turn conducts heat generated by each light emitting element 40 to the second thermally conductive layer 70. Therefore, in the embodiment, the heat-conducting isolation layer 50, the first heat-conducting layer 60 and the second heat-conducting layer 70 can conduct the heat generated by each light-emitting element 40 to the air together, so as to facilitate better heat dissipation and further improve the heat dissipation effect of the display panel 1.
It will be appreciated by those skilled in the art that the above embodiments are illustrative only and not intended to be limiting, and that suitable modifications and variations may be made to the above embodiments without departing from the true spirit and scope of the invention.