PATENT DOCUMENT

Publication Number: US-10522072-B2
Application Number: US-201715796675-A
Country: US
Kind Code: B2

Title: Display with vias for concealed printed circuit and component attachment

Abstract:
An electronic device may include a display. The display may be an organic light-emitting diode display. The organic light-emitting diode display may have a substrate layer, a layer of organic light-emitting diode structures, and a layer of sealant. Vias may be formed in the substrate layer by laser drilling. The vias may be filled with metal using electroplating or other metal deposition techniques. The vias may be connected to contacts on the rear surface of the display. Components such as flexible printed circuits, integrated circuits, connectors, and other circuitry may be mounted to the contacts on the rear surface of the display.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a housing; 
 an organic light-emitting diode display mounted in the housing, wherein the organic light-emitting diode display has an active area and an inactive area and comprises:
 a glass substrate; 
 a thin-film transistor layer on the glass substrate; 
 organic light-emitting diodes on the glass substrate in the active area; 
 a sealant layer that overlaps the organic light-emitting diodes; and 
 a conductive via that extends through the glass substrate in the inactive area and that is electrically connected to the thin-film transistor layer; 
 
 a rigid printed circuit board having first and second opposing surfaces, wherein the via is electrically connected to a conductive structure on the first surface; and 
 a display driver integrated circuit mounted to the second surface, wherein the via electrically connects the display driver integrated circuit to the thin-film transistor layer. 
 
     
     
       2. The electronic device defined in  claim 1 , wherein the conductive via has electroplated metal sidewalls. 
     
     
       3. The electronic device defined in  claim 2 , wherein the organic light-emitting diodes form an array of pixels that displays images to a user. 
     
     
       4. The electronic device defined in  claim 3 , wherein the inactive area is an inactive border region of the display that surrounds the array of pixels. 
     
     
       5. The electronic device defined in  claim 4 , further comprising:
 a plurality of additional conductive vias that extend through the glass substrate, wherein the plurality of additional conductive vias are formed in the inactive border region. 
 
     
     
       6. The electronic device defined in  claim 5 , further comprising:
 a transparent display cover layer over the display. 
 
     
     
       7. An electronic device, comprising:
 a housing; 
 a display mounted in the housing, wherein the display comprises:
 a glass substrate; 
 an array of organic light-emitting diode pixels on the glass substrate that form an active region of the display; 
 an inactive region that surrounds the active region; and 
 a conductive via that extends through the glass substrate in the inactive region and that is electrically connected to the array of organic light-emitting diode pixels; 
 
 a printed circuit board electrically connected to the conductive via; and 
 a display driver integrated circuit mounted to the printed circuit board, wherein the printed circuit board is interposed between the display driver integrated circuit and the glass substrate. 
 
     
     
       8. The electronic device defined in  claim 7 , wherein the display comprises:
 a layer of organic emissive material on the glass substrate that forms the array organic light-emitting diode pixels; and 
 a thin-film transistor layer on the glass substrate that is electrically connected to the array of organic light-emitting diode pixels. 
 
     
     
       9. The electronic device defined in  claim 8 , wherein the display driver integrated circuit provides signals to the thin-film transistor layer through the conductive via. 
     
     
       10. The electronic device defined in  claim 9 , wherein the display further comprises:
 a sealant layer that overlaps the layer of organic emissive material and the thin-film transistor layer, wherein the layer of organic emissive material is between the glass substrate and the sealant layer. 
 
     
     
       11. The electronic device defined in  claim 7 , wherein the conductive via has electroplated metal sidewalls. 
     
     
       12. The electronic device defined in  claim 11 , further comprising:
 a plurality of additional conductive vias that extend through the glass substrate in the inactive region and that are electrically connected to the array of organic light-emitting diode pixels. 
 
     
     
       13. The electronic device defined in  claim 12 , wherein each of the plurality of additional conductive vias has electroplated metal sidewalls. 
     
     
       14. The electronic device defined in  claim 7 , further comprising:
 a transparent display cover layer that overlaps the display. 
 
     
     
       15. An electronic device, comprising:
 a housing; 
 an organic light-emitting diode display mounted in the housing, wherein the organic light-emitting diode display comprises:
 a glass substrate; 
 a thin-film transistor layer on the glass substrate; 
 organic light-emitting diodes on the glass substrate that form an array of pixels that displays images; and 
 a via in the glass substrate in an inactive edge region of the display that runs along the array of pixels, wherein the via has electroplated metal sidewalls that extend through the glass substrate; 
 
 a printed circuit board connected to the via; and 
 a display driver integrated circuit mounted to the printed circuit board, wherein the printed circuit board is interposed between the display driver integrated circuit and the glass substrate and provides signals to the array of pixels through the via. 
 
     
     
       16. The electronic device defined in  claim 15 , wherein the printed circuit board has first and second opposing surfaces, wherein the first surface is interposed between the second surface and the glass substrate, and wherein the display driver integrated circuit is mounted on the second surface. 
     
     
       17. The electronic device defined in  claim 16 , wherein the printed circuit board comprises a first conductive contact on the first surface that is electrically connected to a second conductive contact on the glass substrate. 
     
     
       18. The electronic device defined in  claim 17 , wherein the second conductive contact is electrically connected to the via. 
     
     
       19. The electronic device defined in  claim 18 , wherein the printed circuit board is a rigid printed circuit board. 
     
     
       20. The electronic device defined in  claim 15  further comprising:
 a plurality of additional vias in the glass substrate in the inactive edge region of the display, wherein each of the plurality of additional vias has electroplated metal sidewalls that extend through the glass substrate.

Description:
This application is a continuation of U.S. patent application Ser. No. 14/866,494, filed Sep. 25, 2015, which is a continuation of U.S. patent application Ser. No. 13/284,096, filed on Oct. 28, 2011, each of which are hereby incorporated by reference herein in their entireties. This application claims the benefit of and claims priority to U.S. patent application Ser. No. 14/866,494, filed Sep. 25, 2015, and U.S. patent application Ser. No. 13/284,096, filed on Oct. 28, 2011. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and more particularly, to displays for use in electronic devices. 
     Electronic devices such as portable computers and other electronic equipment may have displays. Driver circuitry may be used to control operation of the displays. In some displays, such as liquid crystal displays, a layer such as a thin-film transistor layer may have a ledge portion on which a display driver integrated circuit is mounted. The minimum size needed for the ledge is at least partly dictated by the size of the driver integrated circuit. In some device designs, such as designs for compact portable devices, the inclusion of this type of driver ledge may give rise to a border region for a liquid crystal display that is larger than desired. In other displays, driver circuitry may be coupled to the display using a flexible printed circuit cable. The attachment structures needed to accommodate attachment of the flexible printed circuit cable to the display may consume more area than desired, particularly in compact devices and in arrangements where thin display borders are desired. 
     It would therefore be desirable to provide improved ways to interconnect displays with associated circuitry such as display driver circuitry. 
     SUMMARY 
     An electronic device may include a display. The display may be an organic light-emitting diode display. The organic light-emitting diode display may, for example, have a substrate layer, a layer of organic light-emitting diode structures, and a layer of sealant. 
     Vias may be formed in a display substrate layer by laser drilling or other via hole formation techniques. The vias may be filled with a conductive material such as metal using electroplating or other metal deposition techniques. The vias may be connected to contacts on the rear surface of the display. Components such as flexible printed circuits, integrated circuits, connectors, and other circuitry may be mounted to the contacts on the rear surface of the display. Conductive materials such as solder and conductive adhesive may be used in mounting components to the contacts. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 and 2  are cross-sectional side views of illustrative electronic devices with displays in accordance with embodiments of the present invention. 
         FIG. 3  is a top view of an illustrative display showing how vias may be used in distributing signals for the display in accordance with an embodiment of the present invention. 
         FIG. 4  is a cross-sectional side view of a portion of a display showing how a via may be formed through the rear surface of the display in accordance with an embodiment of the present invention. 
         FIG. 5  is a diagram showing how a display may be provided with vias so that circuitry can be attached to the rear of the display in accordance with an embodiment of the present invention. 
         FIG. 6  is a diagram showing how a display may be formed from a substrate such as a flexible printed circuit substrate that has backside contacts in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with displays having vias. An illustrative electronic device of the type that may be provided with a display having vias is shown in  FIG. 1 . Electronic device  10  of  FIG. 1  may be a computer, a personal computer, a tablet computer, a cellular telephone, a media player, a gaming device, a navigation device, or other electronic equipment. As shown in the cross-sectional view of device  10  in  FIG. 1 , electronic device  10  may include housing  12 , a display such as display  14 , and internal components such as components  16 . 
     Housing  12  may be formed from plastic, metal, fiber-composite materials, glass, ceramic, other materials, or combinations of these materials. Display  14  may be a liquid crystal display, an organic light-emitting diode display, a plasma display, an electrochromic display, an electrophoretic ink display, an electrowetting display, or other suitable display. Examples in which display  14  is implemented as an organic light-emitting diode display are sometimes described herein as an example. This is, however, merely illustrative. Display  14  may be formed using any suitable display if desired. If desired, display  14  may be covered with a cover layer of glass or plastic or other protective display layer. In the example of  FIG. 1 , the cover layer has been omitted. 
     Internal components  16  may include printed circuits such as rigid printed circuit boards (e.g., fiberglass-filled epoxy printed circuit boards), flexible printed circuits (“flex circuits”) formed from flexible sheets of polymers such as polyimide, “rigid flex” printed circuits (e.g., printed circuit boards including rigid printed circuit portions with integral flex circuit tails), or other printed circuit structures. As an example, device  10  may include a printed circuit such as printed circuit board  18  on which one or more components such as electrical components  20  or other internal components  16  have been mounted. Components  20  may include switches, connectors, discrete components such as capacitors, resistors, and inductors, integrated circuits, and other electronic components. 
     As shown in  FIG. 1 , display  14  may have multiple layers. For example, display  14  may be an organic light-emitting diode display having a substrate layer such as substrate layer  22 , a layer of thin-film transistor structures (e.g., polysilicon transistors and/or amorphous silicon transistors) and organic emissive material such as layer  24 , and a sealant layer such as layer  26 . Substrate layer  22  may be formed from a rigid or flexible dielectric such as glass, ceramic, or plastic. As an example, substrate  22  in display  14  may be formed from a flexible sheet of polymer such as a layer of polyimide. 
     Vias such as vias  28  may be formed in display  14 . As shown in  FIG. 1 , for example, vias  28  may be formed through substrate layer  22  so that electrical contacts may be formed on the rear (inner) surface of substrate  22  and display  14 . Vias  28  may be formed by laser drilling and electroplating or using other fabrication techniques. Conductive material in vias  28  such as metal (e.g., gold plated copper) may be used to form signal paths in display  14 . The signal paths may, for example, be used to route signals between the circuitry of layer  24  (e.g., thin-film transistors) and external circuitry such as display driver circuitry. 
     In the example of  FIG. 1 , display driver circuitry for display  14  has been provided using display driver integrated circuit  30 . Display driver integrated circuit  30  (in the  FIG. 1  example) has been mounted on printed circuit  32 . Printed circuit  32  may be a rigid printed circuit board or a flex circuit. For example, printed circuit  32  may be a flex circuit that includes one or more layers of patterned interconnect lines such as traces  34 . Traces  34  may be electrically connected between one or more vias in substrate layer  22  of display  14  and driver integrated circuit  30 . If desired, traces  34  may be connected to a communications path formed from flex circuit  36  (e.g., a flex circuit that is connected to printed circuit board  18  directly or, as shown in  FIG. 1 , a flex circuit that is connected to components  20  on printed circuit board  18  via flex circuit connector  20 ′). The connection between flex circuit  36  and printed circuit  32  may be formed using a connector or by directly attaching flex circuit  36  to traces  34  on printed circuit  32 . 
     By using vias  28  in layer  22 , the need to form flex circuit attachments or driver circuit attachments to the front (upper/exterior) surface of display  14  may be avoided, allowing the edge regions surrounding the active display pixels in display  14  to be minimized. More area in display  14  may therefore be available for forming the array of pixels that displays images to a user. 
     If desired, a jumper structure such as structure  38  may be attached to vias on the backside of substrate  22  and may be used to route signals between two or more different locations in display  14 . Structure  38  may be formed from a printed circuit such as a flex circuit or rigid printed circuit board. Traces  40  in structures  38  may be used to help distribute signals for display  14 . Any suitable signals may be routed through flex circuits or other jumper structures on the rear of display  14 . For example, structures  38  may be used to carry gate line signals, data line signals, power supply signals, or other information or power signals associated with operating display  14 . By implementing at least some of the interconnect resources associated with display  14  using structures located on the rear surface of display  14 , more room may be made available on the front surface of display  14  for active pixel structures and the size of any inactive border regions on the front side of display  14  may be minimized. 
     In the illustrative arrangement of  FIG. 1 , flex circuit  32  is being used to support display driver integrated circuit  30  and a separate flex circuit such as flex circuit  36  is being used to couple flex circuit  32  to printed circuit board  18  (using connector  20 ′). Other arrangements may be used if desired. For example, flex circuit  32  may be connected directly to traces on printed circuit board  18  (e.g., using anisotropic conductive film or solder connections) or flex circuit  32  may be connected directly to connector  20 ′. There may be more than one flex circuit such as flex circuit  32  that is interconnected between rear surface vias  28  on display  14  and circuitry such as circuitry in components  20  on printed circuit board  18 . Supplemental interconnection pathways such as traces  40  of flex circuit  38  may be provided on one or more, two or more, or three or more integrated circuits. Flex circuits such as flex circuit  32  may include mounted circuits such as display driver integrated circuit  30  for controlling the operation of display  14  and may, if desired, include supplemental interconnect lines for forming gate line paths, data line paths, power lines paths, or other signal paths in device  10 . Supplemental interconnect lines for forming gate line paths, data line paths, power lines paths, or other signal paths in device  10  may also be formed using jumper structures  38 . 
     As shown in  FIG. 2 , a printed circuit such as flex circuit  42  may have traces such as traces  44  that form a path between vias  28  in substrate  22  of display  14  and circuitry on printed circuit board  18 . A connector such as connector  20 ′ of  FIG. 2  or a direct attachment scheme (e.g., using solder or anisotropic conductive film) may be used to interconnect traces  44  to traces on printed circuit board  18  such as traces  46 . Display driver circuitry  30  (e.g., a display driver integrated circuit) may, if desired, be mounted on printed circuit  18  and may be coupled to traces  44  in printed circuit  42  via traces  46 . 
     An arrangement that may be used for providing vias  28  in display  14  is shown the top view of illustrative display  14  of  FIG. 3 . As shown in  FIG. 3 , display  14  may display pixels such as display pixels  48 . Display pixels  48  may each contain an organic light-emitting diode structure for emitting light for display  14 . Display pixels  48  may be organized in an array such as array  50 . Array  50  may contain any suitable number or rows and columns of display pixels  48 . For example, array  50  may have hundreds of rows and/or hundreds of columns of display pixels  48  (as an example). Vertical and horizontal control lines may be used in supplying control signals to display pixels  48 . For example, signals may be applied to respective columns of display pixels  48  using vertical signal lines such as lines  52  and may be applied to respective rows of display pixels  48  using horizontal signal lines such as lines  54 . 
     If desired, signal lines such as lines  52  may be coupled to vias in substrate layer  22  of display  14  such as vias  28 A. Signal lines such as lines  54  may be coupled to vias in substrate layer  22  of display  14  such as vias  28 B. Vias in substrate layer  22  such as vias  28 C may be formed within array  50  (e.g., at intermediate locations in the rows or columns of display pixels  48 ). Edge vias such as vias  28 D may also be formed in substrate  22  and may be used for handling signals associated with operating display pixels  48  (e.g., signals for lines  52  and/or  54 ). 
     A cross-sectional side view of a portion of display  14  containing a via is shown in  FIG. 4 . Via  28  may be one of vias  28  of  FIGS. 1 and 2 , one of vias  28 A,  28 B,  28 C, or  28 D of  FIG. 3 , or other vias formed through substrate  22  of display  14 . As shown in  FIG. 4 , via  28  may include tubular metal sidewalls such as sidewalls  60  that coat the cylindrical inner surface of a through hole in layer  22 . Sidewalls  60  may be formed by any suitable fabrication technique. For example, sidewalls  60  may be formed using electrodeposition (e.g., formation of a thin seed layer followed by electroplating of a metal such as copper and, if desired, a subsequent coating of a metal such as gold). With a via structure of the type shown in  FIG. 4 , via  28  is formed from a hole (e.g., a cylindrical hole) in substrate  22  and is lined with a tubular layer of metal. Other types of vias may be formed in layer  22  if desired (e.g., via holes that are plugged with solid metal, etc.). 
     If desired, traces may be formed on the surface of substrate  22 . As shown in  FIG. 4 , for example, contact pad  62  may be formed on rear surface  64  of display  14 . Contact  62  may be formed from a metal trace that is electrically shorted to sidewalls  60  of via  28 . Additional patterned conductive structures may be formed on surface  64  of substrate  22  if desired. The example of  FIG. 4  is merely illustrative. 
       FIG. 5  is a diagram showing how a display may be provided with vias. Initially, a display substrate such as substrate  22  may be provided. Substrate  22  may be, for example, a layer of polymer such as a layer of polyimide. 
     Via hole formation equipment  70  such as laser drilling equipment may be used to form one or more via holes such as via hole  72  in substrate  22 . 
     Following formation of via holes such as via hole  72 , conductive material deposition equipment such as metal plating equipment  74  may be used to form conductive structures for vias  28  such as conductive sidewalls  60 . Traces such as contact trace  62  may also be formed on lower surface  64  of substrate  22 . 
     Organic light-emitting diode (OLED) fabrication equipment  76  or other display fabrication equipment may be used to complete display  14 . For example, OLED fabrication equipment  76  may be used to form thin-film transistor structures and interconnects in layer  24 . Layer  24  may include organic emissive material and light-emitting diode structures that are used to form display pixels such as display pixels  48  of  FIG. 3 . A sealant layer such as sealant layer  26  (e.g., a polymer layer) may then be formed over the front (upper) surface of display  14  to protect the structures of layer  24 . 
     Additional processing equipment  78  may then be used to form electrical connections to additional circuitry  84 . As shown in  FIG. 5 , conductive material  82  may be used in forming electrical connections between contacts such as contact  62  on display  14  (e.g., contacts on surface  64  of substrate  22 ) and associated contacts such as contact  80  on additional circuitry  84 . Conductive material  82  may be solder, metal associated with a weld, part of a connector, conductive adhesive (e.g., anisotropic conductive film), or other suitable material for forming an electrical connection between via  28  and additional circuitry  84 . Additional circuitry  84  may be a printed circuit or other circuitry. For example, additional circuitry  84  may be a flex circuit on which integrated circuits and/or other electrical components are mounted, a flex circuit cable that is attached to a printed circuit board with components, a rigid printed circuit board, or other suitable circuitry (see, e.g., the illustrative arrangements of  FIGS. 1, 2, and 3 ). 
       FIG. 6  is a diagram showing how display  14  may be formed from a two-sided printed circuit layer that serves as substrate  22 . 
     Initially, printed circuit processing equipment  86  may be used to produce patterned two-sided printed circuit  22 . Patterned two-sided printed circuit  22  may include patterned traces  88  and patterned traces  90  on opposing first (upper) and second (lower) surfaces. If desired, one or more layers of internal printed circuit traces such as traces  92  may be used to interconnect upper surface traces  88  and lower surface traces  90  (i.e., printed circuit layer  22  may include multiple sublayers of dielectric such as polyimide and one or more corresponding sublayers of patterned traces). Traces  92  may include vias  28 . 
     Following formation of a multilayer printed circuit such as a two-sided printed circuit substrate or a multilayer printed circuit substrate that includes one or more patterned internal layers of traces and/or one or two exposed surfaces covered with of external traces such as substrate  22 , OLED processing equipment  94  may be used to complete the formation of OLED display  14  by forming organic emissive material and light-emitting diode structures in layer  24  and covering layer  24  with sealant layer  26 . 
     Component mounting tools and other processing equipment  96  may be used to mount components  102  to substrate  22 . In particular, conductive material  104  such as solder, welds, conductive material associated with connector structures, anisotropic conductive film or other conductive adhesive, or other conductive material may be used to connect traces (contacts)  100  on components  102  to corresponding traces  90  on rear surface  64  of display  14 . Examples of components  102  that equipment  96  may attach to traces  90  include integrated circuits, discrete components such as resistors, capacitors, and inductors, connectors, flex circuit cables and other printed circuit structures, and other circuitry. Components  102  may be, for example, surface mount technology (SMT) components and equipment  96  may be a pick-and-place tool. 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20171027
Publication Date: 20191231
Grant Date: 20191231
Priority Date: 20111028
Inventors: WRIGHT, DEREK
ROTHKOPF, FLETCHER R.
MYERS, SCOTT A.
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K1/115", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2300/0426", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/3208", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2300/0426", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/3208", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01L27/3276", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L51/52", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2300/0426", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/115", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/3208", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G3/32", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K59/131", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/131", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K50/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/80", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/80", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 47192085