Patent Publication Number: US-9843016-B2

Title: OLED package structure and OLED packaging method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of co-pending U.S. patent application Ser. No. 14/758,244, filed on Jun. 29, 2015, which is a national stage of PCT Application No. PCT/CN2015/075846, filed on Apr. 3, 2015, claiming foreign priority of Chinese Patent Application No. 201510039439.X, filed on Jan. 26, 2015. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of packaging technology, and in particular to an OLED (Organic Light-Emitting Diode) package structure and an OLED packaging method. 
     2. The Related Arts 
     OLED stands for organic light emitting diode, which has various advantages, such as being self-luminous, high brightness, wide view angle, high contrast, being flexible, and low power consumption and is considered the new generation of display measures that gradually takes the place of the conventional liquid crystal displays by being widely used in mobile phone screens, computer displays, and full-color televisions. The OLED displaying technology is different from the liquid crystal displaying technology in that no backlighting is needed and an extremely thin coating layer of an organic material and a glass substrate are used in such a way that when an electrical current flows therethrough, the organic material emits light. However, since the organic material is highly reactive to moisture and oxygen, an OLED display, which is a display device based on such an organic material, must require extremely high standard of packaging. 
     Currently, packaging of an OLED device is generally done with a dam-and-desiccant manner.  FIG. 1  is a cross-sectional view showing a conventional OLED package structure. The structure comprises a substrate  100 , a package lid  200  opposite to the substrate  100 , an OLED device  110  that is arranged between the substrate  100  and the package lid  200  and mounted on the substrate  100 , desiccant  210  that is arranged between the substrate  100  and the package lid  200  and mounted to the package lid  200 , and enclosure resin  300  that is located between the substrate  100  and the package lid  200  and bonds the substrate  100  and the package lid  200  together. A recess  220  is formed on an inner side of the package lid  200  and corresponds to an outer circumference of the OLED device  110 . The desiccant  210  is mounted in the recess  220  to absorb moisture penetrating through the enclosure resin  300  and entering the interior of the OLED in order to enhance the performance of the OLED device and extend the life span of the OLED. However, such an OLED package structure has a large gap existing in the interior thereof, leading to reduced mechanical strength and easy breaking. 
     Thus, it is desired to provide a novel OLED package structure and an OLED packaging method that overcome the above problems. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an organic light-emitting diode (OLED) package structure, which has a high mechanical strength, good sealing tightness, and extended life span. 
     Another object of the present invention is to provide an OLED packaging method, which significantly enhances the mechanical strength of a package structure and improves sealing tightness so as to improve the performance of an OLED device and extend the life span of the OLED device. 
     To achieve the above objects, the present invention provides an OLED package structure, which comprises a substrate, a package lid arranged opposite to the substrate, an OLED device arranged between the substrate and the package lid and mounted to the substrate, and enclosure resin located between the substrate and the package lid and bonding the substrate and the package lid together; 
     wherein the package lid comprises a recess formed therein at a location corresponding to the OLED device and the recess comprises a plurality of corrugation projection structures arranged therein and extending outwards from a bottom of the recess, wherein desiccant is attached to the bottom of the recess in an area between two adjacent ones of the corrugation projection structures. 
     The recess has a depth less than or equal to ⅓ of a thickness of the package lid. 
     The corrugation projection structures have a height less than or equal to the depth of the recess. 
     The desiccant comprises calcium oxide. 
     The present invention also provides an OLED package structure, which comprises a substrate, a package lid arranged opposite to the substrate, an OLED device arranged between the substrate and the package lid and mounted to the substrate, and enclosure resin located between the substrate and the package lid and bonding the substrate and the package lid together; 
     wherein the package lid comprises a recess formed therein at a location corresponding to the OLED device and the recess comprises a plurality of corrugation projection structures arranged therein and extending outwards from a bottom of the recess, wherein desiccant is attached to the bottom of the recess in an area between two adjacent ones of the corrugation projection structures; 
     wherein the recess has a depth less than or equal to ⅓ of a thickness of the package lid; 
     wherein the desiccant comprises calcium oxide. 
     The present invention further provides an organic light-emitting diode (OLED) packaging method, which comprises the following steps: 
     (1) providing a substrate and a package lid; 
     (2) forming a recess in the package lid and forming a plurality of corrugation projection structures in the recess to extend outward from a bottom of the recess, wherein the corrugation projection structures are connected to two parallel sidewalls of the recess and are perpendicular to the two sidewalls; 
     (3) attaching desiccant to the bottom of the recess in an area between two adjacent ones of the corrugation projection structures; 
     (4) coating enclosure resin on the package lid around and outside a perimeter of the recess; 
     (5) forming an OLED device on the substrate in an area corresponding to the recess; 
     (6) laminating the substrate and the package lid together; 
     (7) applying ultraviolet light to irradiate for curing the enclosure resin so as to complete packaging the substrate with the package lid. 
     Step (2) applies an acid etching process to form the recess and the corrugation projection structures in the recess. 
     The recess has a depth less than or equal to ⅓ of a thickness of the package lid. 
     The corrugation projection structures have a height less than or equal to the depth of the recess. 
     The desiccant of step (3) comprises calcium oxide. 
     Step (5) applies a vapor deposition process to form the OLED device. 
     The efficacy of the present invention is that the present invention provides an OLED package structure, which comprises a recess formed in a package lid and a plurality of corrugation projection structures arranged in the interior of the recess and extending outwards from a bottom of the recess to help significantly improve the performance of the package lid resisting shocks and pressurization so as to provide the OLED package structure of the present invention with an increased mechanical strength and also, desiccant is mounted in the interior of the recess to absorb moisture penetrating through an enclosure resin into the interior of the package structure so as to achieve improved sealing tightness, extended life span, and a simple structure that makes manufacture easy. The present invention provides an OLED packaging method, which has a simple manufacture process and is of high operability. 
     For better understanding of the features and technical contents of the present invention, reference will be made to the following detailed description of the present invention and the attached drawings. However, the drawings are provided for the purposes of reference and illustration and are not intended to impose limitations to the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The technical solution, as well as other beneficial advantages, of the present invention will be apparent from the following detailed description of an embodiment of the present invention, with reference to the attached drawing. 
       In the drawing: 
         FIG. 1  is a cross-sectional view showing a conventional OLED (Organic Light-Emitting Diode) package structure; 
         FIG. 2  is a cross-sectional view showing an OLED package structure according to the present invention; 
         FIG. 3  is a flow chart illustrating an OLED packaging method according to the present invention; 
         FIG. 4  is a schematic view illustrating step 1 of the OLED packaging method according to the present invention; 
         FIG. 5  is a schematic view illustrating step 2 of the OLED packaging method according to the present invention; 
         FIG. 6  is a schematic view illustrating step 3 of the OLED packaging method according to the present invention; 
         FIG. 7  is a top plan view illustrating step 3 of the OLED packaging method according to the present invention; 
         FIG. 8  is a schematic view illustrating step 4 of the OLED packaging method according to the present invention; 
         FIG. 9  is a top plan view illustrating step 4 of the OLED packaging method according to the present invention; 
         FIG. 10  is a schematic view illustrating step 5 of the OLED packaging method according to the present invention; 
         FIG. 11  is a schematic view illustrating step 6 of the OLED packaging method according to the present invention; and 
         FIG. 12  is a schematic view illustrating step 7 of the OLED packaging method according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     To further expound the technical solution adopted in the present invention and the advantages thereof, a detailed description is given to a preferred embodiment of the present invention and the attached drawings. 
     Referring to  FIG. 2 , the present invention provides an organic light-emitting diode (OLED) package structure, which comprises a substrate  1 , a package lid  2  arranged opposite to the substrate  1 , an OLED device  11  arranged between the substrate  1  and the package lid  2  and mounted to the substrate  1 , and enclosure resin  3  located between the substrate  1  and the package lid  2  and bonding the substrate  1  and the package lid  2  together. 
     The package lid  2  comprises a recess  21  formed therein at a location corresponding to the OLED device  11 . The recess  21  comprises a plurality of corrugation projection structures  212  arranged therein and formed on and extending outwards from a bottom thereof, wherein desiccant  211  is attached to the bottom of the recess  21  in an area between two adjacent ones of the corrugation projection structures  212 . 
     Specifically, the corrugation projection structures  212  are formed to connect to two parallel sidewalls of the recess  21  and are perpendicular to the two sidewalls. 
     Specifically, the corrugation projection structures  212  each comprise a plurality of projections and a passageway delimited between every two adjacent ones of the projections. Preferably, the substrate  1  and the package lid  2  are both glass boards and the substrate  1  is a thin-film transistor (TFT) substrate. 
     Specifically, the enclosure resin  3  comprises ultraviolet (UV) curable resin. 
     Preferably, the recess  21  has a depth that is less than or equal to one third (⅓) of a thickness of the package lid  2  and the corrugation projection structures  212  have a height less than or equal to the depth of the recess  21 . 
     The arrangement of the corrugation projection structures  212  significantly increases the performance of the package lid resisting shocks and pressurization and thus providing the OLED package structure of the present invention with an increased mechanical strength. 
     Preferably, the desiccant  211  comprises calcium oxide, which absorbs moisture penetrating through the enclosure resin  3  and entering the interior of the package structure. 
     The above-described OLED package structure comprises a package lid in which a recess is formed and a plurality of corrugation projection structures arranged in the recess and formed on and extending outwards from a recess bottom to help significantly improve the performance of the package lid resisting shocks and pressurization so as to provide the OLED package structure of the present invention with an increased mechanical strength and also, desiccant is mounted in the interior of the recess to absorb moisture penetrating through an enclosure resin into the interior of the package structure so as to achieve improved sealing tightness, extended life span, and a simple structure that makes manufacture easy. 
     Referring to  FIGS. 3-12 , the present invention also provides an OLED packaging method, which comprises the following steps: 
     Step 1: as shown in  FIG. 4 , providing a substrate  1  and a package lid  2 . 
     Preferably, the substrate  1  and the package lid  2  are both glass boards and the substrate  1  is a TFT substrate. 
     Step 2: as shown in  FIG. 5 , forming a recess  21  in the package lid  2  and forming a plurality of corrugation projection structures  212  in the recess  21  to extend outward from a bottom of the recess  21 , wherein the corrugation projection structures  212  are connected to two parallel sidewalls of the recess  21  and are perpendicular to the two sidewalls. 
     Specifically, the corrugation projection structures  212  each comprise a plurality of projections and a passageway delimited between every two adjacent ones of the projections. The arrangement of the corrugation projection structures  212  significantly increases the performance of the package structure resisting shocks and pressurization and thus providing an increased mechanical strength thereof. 
     Specifically, the recess  21  and the corrugation projection structure  212  can be formed through an acid etching process. 
     Preferably, the recess  21  has a depth that is less than or equal to one third (⅓) of a thickness of the package lid  2  and the corrugation projection structures  212  have a height less than or equal to the depth of the recess  21 . 
     Step 3: as shown in  FIGS. 6 and 7 , attaching desiccant  211  to the bottom of the recess  21  in an area between two adjacent ones of the corrugation projection structures  212 . 
     Preferably, the desiccant  211  comprises calcium oxide, which absorbs moisture penetrating through the enclosure resin  3  and entering the interior of the package structure. 
     Step 4: as shown in  FIG. 8-9 , coating enclosure resin  3  on the package lid  2  around and outside a perimeter of the recess  21 . 
     Specifically, the enclosure resin  3  comprises UV curable resin. 
     Step 5: as shown in  FIG. 10 , forming an OLED device  11  on the substrate  1  in an area corresponding to the recess  21 . 
     Specifically, the OLED device  11  is formed through a vapor deposition process. 
     Step 6: as shown in  FIG. 11 , laminating the substrate  1  and the package lid  2  together. 
     Step 7: as shown in  FIG. 12 , applying ultraviolet light to irradiate for curing the enclosure resin  3  so as to complete packaging the substrate  1  with the package lid  2 . 
     The above-described OLED packaging method comprises forming a recess in a package lid and simultaneously forming a plurality of corrugation projection structures in the recess to extend outwards from a bottom of recess so as to improve the performance of the package lid resisting shocks and pressurization and thus providing the OLED package structure with an improved mechanical strength and also comprises attaching desiccant to the interior of the recess for absorbing moisture penetrating through enclosure resin into the interior of the package structure thereby improving sealing tightness and effectively extending the life span of the OLED device and also providing a simple manufacture process that is of high operability. 
     In summary, the present invention provides an OLED package structure, which comprises a recess formed in a package lid and a plurality of corrugation projection structures arranged in the interior of the recess and extending outwards from a bottom of the recess to help significantly improve the performance of the package lid resisting shocks and pressurization so as to provide the OLED package structure of the present invention with an increased mechanical strength and also, desiccant is mounted in the interior of the recess to absorb moisture penetrating through an enclosure resin into the interior of the package structure so as to achieve improved sealing tightness, extended life span, and a simple structure that makes manufacture easy. The present invention provides an OLED packaging method, which has a simple manufacture process and is of high operability. 
     Based on the description given above, those having ordinary skills of the art may easily contemplate various changes and modifications of the technical solution and technical ideas of the present invention and all these changes and modifications are considered within the protection scope of right for the present invention.