PATENT DOCUMENT

Publication Number: US-12112681-B2
Application Number: US-202217825367-A
Country: US
Kind Code: B2

Title: Electronic devices with displays and interposer structures

Abstract:
An electronic device may have a display. The display may include an array of pixels formed on a silicon substrate. Display driver circuitry may be formed in a display driver integrated circuit that outputs display data and other control signals for operating the display. An interposer structure may be included in the electronic device. The interposer structure may be attached to the silicon display substrate and may only partially overlap the silicon display substrate. The display driver integrated circuit may be attached to the interposer structure and provide signals to the display pixels through the interposer structure. In another possible arrangement, the display driver integrated circuit may bridge a gap between the silicon display substrate and the flexible printed circuit. The display driver integrated circuit only partially overlaps the silicon display substrate in this arrangement.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a silicon substrate; 
 an array of display pixels formed on the silicon substrate; 
 an interposer structure that is attached to the silicon substrate; 
 a display driver integrated circuit that is attached to the interposer structure, wherein the display driver integrated circuit is configured to provide data to the array of display pixels through the interposer structure; 
 a rigid printed circuit board; 
 a flexible printed circuit that is attached to the rigid printed circuit board and the interposer structure, wherein the silicon substrate has an edge and wherein the interposer structure bridges a gap between the flexible printed circuit and the edge of the silicon substrate; and 
 a support structure that supports the silicon substrate, wherein the support structure has a portion that extends past the edge of the silicon substrate towards the flexible printed circuit, and wherein the display driver integrated circuit is interposed between the portion of the support structure and the interposer structure. 
 
     
     
       2. The electronic device defined in  claim 1 , wherein the interposer structure comprises silicon. 
     
     
       3. The electronic device defined in  claim 1 , wherein the interposer structure has a first portion that is attached to the silicon substrate, a second portion that is attached to the display driver integrated circuit, and a third portion that is attached to the flexible printed circuit. 
     
     
       4. The electronic device defined in  claim 3 , wherein the first portion comprises a first plurality of contact pads that is electrically connected to a respective second plurality of contact pads in the flexible printed circuit, wherein the second portion comprises a third plurality of contact pads that is electrically connected to a respective fourth plurality of contact pads in the display driver integrated circuit, and wherein the third portion comprises a fifth plurality of contact pads that is electrically connected to a respective sixth plurality of contact pads in the silicon substrate. 
     
     
       5. The electronic device defined in  claim 4 , wherein the fifth plurality of contact pads is electrically connected to the sixth plurality of contact pads using anisotropic conductive films. 
     
     
       6. The electronic device defined in  claim 5 , wherein the third plurality of contact pads is electrically connected to the fourth plurality of contact pads using solder. 
     
     
       7. The electronic device defined in  claim 1 , further comprising:
 a filler that is interposed between the portion of the support structure and the display driver integrated circuit, wherein the filler conforms to the display driver integrated circuit. 
 
     
     
       8. The electronic device defined in  claim 1 , wherein the flexible printed circuit has first and second opposing ends, wherein the first end is attached to the rigid printed circuit board, and wherein the second end is attached to the interposer structure. 
     
     
       9. The electronic device defined in  claim 8 , wherein the flexible printed circuit is bent between the first and second ends. 
     
     
       10. The electronic device defined in  claim 1 , wherein the interposer structure includes power delivery circuitry. 
     
     
       11. An electronic device comprising:
 a silicon substrate; 
 an array of display pixels formed on the silicon substrate; 
 a rigid printed circuit board; 
 a flexible printed circuit that is attached to the rigid printed circuit board; 
 a display driver integrated circuit that is configured to provide data to the array of display pixels, wherein the display driver integrated circuit bridges a gap between the flexible printed circuit and the silicon substrate, wherein a first portion of the display driver integrated circuit is attached to the flexible printed circuit, and wherein a second portion of the display driver integrated circuit is attached to the silicon substrate; 
 a support structure that supports the silicon substrate and is overlapped by the silicon substrate, wherein the support structure has an extension that extends past an edge of the silicon substrate and is not overlapped by the silicon substrate; and 
 a spacer interposed between the extension and the display driver integrated circuit. 
 
     
     
       12. The electronic device defined in  claim 11 , wherein the flexible printed circuit has first and second opposing ends, wherein the first end is attached to the rigid printed circuit board, wherein the second end is attached to the display driver integrated circuit, and wherein the flexible printed circuit is bent between the first and second ends. 
     
     
       13. An electronic device comprising:
 a silicon substrate; 
 an array of display pixels formed on the silicon substrate; 
 a silicon interposer having a first contact that is bonded to a respective second contact in the silicon substrate, wherein the silicon interposer has opposing first and second surfaces; 
 a display driver integrated circuit having a third contact that is bonded to a respective fourth contact in the silicon interposer, wherein the first contact and the fourth contact are located on the first surface of the silicon interposer and wherein the display driver integrated circuit is configured to provide data to the array of display pixels through the silicon interposer; 
 a flexible printed circuit having a fifth contact that is bonded to a respective sixth contact in the silicon interposer; and 
 a rigid printed circuit board having a seventh contact that is bonded to a respective eighth contact in the flexible printed circuit, wherein the flexible printed circuit is interposed between the first surface of the silicon interposer and the rigid printed circuit board in a direction perpendicular to the first surface of the silicon interposer. 
 
     
     
       14. The electronic device defined in  claim 11 , wherein the first portion overlaps the flexible printed circuit in a first direction and the second portion overlaps the silicon substrate in the first direction. 
     
     
       15. The electronic device defined in  claim 11 , wherein the display driver integrated circuit has a first contact that is bonded to a respective second contact in the flexible printed circuit, and wherein the display driver integrated circuit has a third contact that is bonded to a respective fourth contact in the silicon substrate. 
     
     
       16. The electronic device defined in  claim 1 , wherein the support structure serves as a heat sink for the silicon substrate. 
     
     
       17. The electronic device defined in  claim 13 , further comprising:
 a heat sink structure that supports the silicon substrate, wherein the heat sink structure has a portion that extends past the edge of the silicon substrate. 
 
     
     
       18. The electronic device defined in  claim 11 , wherein the spacer comprises a plastic spacer. 
     
     
       19. The electronic device defined in  claim 11 , wherein the spacer is attached to at least the extension or the display driver integrated circuit with adhesive. 
     
     
       20. The electronic device defined in  claim 11 , wherein the array of display pixels emit light in a first direction and wherein the flexible printed circuit is interposed between the display driver integrated circuit and the rigid printed circuit board in a second direction parallel to the first direction.

Description:
This application claims priority to U.S. provisional patent application No. 63/240,311, filed Sep. 2, 2021, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to electronic devices with displays. 
     Electronic devices often include displays. For example, an electronic device may have an organic light-emitting diode (OLED) display based on organic light-emitting diode pixels or a liquid crystal display (LCD) based on liquid crystal display pixels. The display may include display driver circuitry that is configured to provide display data to the pixels and gate driver circuitry that is configured to control the pixels. 
     It is within this context that the embodiments herein arise. 
     SUMMARY 
     An electronic device may have a display. The display may include an array of pixels formed on a silicon substrate. The display may include display driver circuitry that is configured to provide display data to the pixels and gate driver circuitry that is configured to control the pixels. 
     The display driver circuitry may be formed in a display driver integrated circuit that outputs display data and other control signals for operating the display. An interposer structure may be included in the electronic device. The interposer structure may be attached to the silicon display substrate and may only partially overlap the silicon display substrate. The display driver integrated circuit may be attached to the interposer structure and provide signals to the display pixels through the interposer structure. The interposer structure may have a first portion that is attached to the silicon display substrate, a second portion that is attached to the display driver integrated circuit, and a third portion that is attached to a flexible printed circuit. 
     In another possible arrangement, the display driver integrated circuit may bridge a gap between the silicon display substrate and the flexible printed circuit. The display driver integrated circuit only partially overlaps the silicon display substrate in this arrangement. 
     The silicon display substrate may be formed on a support structure that provides mechanical support for the display substrate. The support structure may be formed from a metal material and may also serve as a heat sink for the display substrate. The support structure may have an extension that extends past an edge of the silicon display substrate. A filler may be included between the support structure extension and the display driver integrated circuit and/or interposer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of an illustrative electronic device having a display in accordance with an embodiment. 
         FIG.  2    is a schematic diagram of an illustrative display in accordance with an embodiment. 
         FIG.  3    is a cross-sectional side view of an illustrative electronic device with a display driver integrated circuit that is mounted directly on a display substrate in accordance with an embodiment. 
         FIG.  4    is a cross-sectional side view of an illustrative electronic device with a display driver integrated circuit that is mounted to an interposer structure in accordance with an embodiment. 
         FIG.  5    is a cross-sectional side view of an illustrative electronic device with a display driver integrated circuit that serves as an interposer structure in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative electronic device of the type that may be provided with a display is shown in  FIG.  1   . Electronic device  10  may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a display, a computer display that contains an embedded computer, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, or other electronic equipment. Electronic device  10  may have the shape of a pair of eyeglasses (e.g., supporting frames), may form a housing having a helmet shape, or may have other configurations to help in mounting and securing the components of one or more displays on the head or near the eye of a user. 
     As shown in  FIG.  1   , electronic device  10  may include control circuitry  16  for supporting the operation of device  10 . Control circuitry  16  may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access memory), etc. Processing circuitry in control circuitry  16  may be used to control the operation of device  10 . The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, application-specific integrated circuits, etc. 
     Input-output circuitry in device  10  such as input-output devices  12  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  12  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, sensors, light-emitting diodes and other status indicators, data ports, etc. A user can control the operation of device  10  by supplying commands through input resources of input-output devices  12  and may receive status information and other output from device  10  using the output resources of input-output devices  12 . 
     Input-output devices  12  may include one or more displays such as display  14 . Display  14  may be a touch screen display that includes a touch sensor for gathering touch input from a user or display  14  may be insensitive to touch. A touch sensor for display  14  may be based on an array of capacitive touch sensor electrodes, acoustic touch sensor structures, resistive touch components, force-based touch sensor structures, a light-based touch sensor, or other suitable touch sensor arrangements. A touch sensor for display  14  may be formed from electrodes formed on a common display substrate with the display pixels of display  14  or may be formed from a separate touch sensor panel that overlaps the pixels of display  14 . If desired, display  14  may be insensitive to touch (i.e., the touch sensor may be omitted). Display  14  in electronic device  10  may be a head-up display that can be viewed without requiring users to look away from a typical viewpoint or may be a head-mounted display that is incorporated into a device that is worn on a user&#39;s head. If desired, display  14  may also be a holographic display used to display holograms. 
     Control circuitry  16  may be used to run software on device  10  such as operating system code and applications. During operation of device  10 , the software running on control circuitry  16  may display images on display  14 . 
       FIG.  2    is a diagram of an illustrative display  14 . As shown in  FIG.  2   , display  14  may include layers such as substrate layer  26 . Substrate layers such as layer  26  may be formed from rectangular planar layers of material or layers of material with other shapes (e.g., circular shapes or other shapes with one or more curved and/or straight edges). The substrate layers of display  14  may include glass layers, polymer layers, silicon layers, composite films that include polymer and inorganic materials, metallic foils, etc. 
     Display  14  may have an array of pixels  22  for displaying images for a user such as pixel array  28 . Pixels  22  in array  28  may be arranged in rows and columns. The edges of array  28  may be straight or curved (i.e., each row of pixels  22  and/or each column of pixels  22  in array  28  may have the same length or may have a different length). There may be any suitable number of rows and columns in array  28  (e.g., ten or more, one hundred or more, or one thousand or more, etc.). Display  14  may include pixels  22  of different colors. As an example, display  14  may include red pixels, green pixels, and blue pixels. Pixels of other colors such as cyan, magenta, and yellow might also be used. 
     Display driver circuitry  20  may be used to control the operation of pixels  28 . Display driver circuitry  20  may be formed from integrated circuits, thin-film transistor circuits, and/or other suitable circuitry. Illustrative display driver circuitry  20  of  FIG.  2    includes display driver circuitry  20 A and additional display driver circuitry such as gate driver circuitry  20 B. Gate driver circuitry  20 B may be formed along one or more edges of display  14 . For example, gate driver circuitry  20 B may be arranged along the left and right sides of display  14  as shown in  FIG.  2   . 
     As shown in  FIG.  2   , display driver circuitry  20 A (e.g., one or more display driver integrated circuits, thin-film transistor circuitry, etc.) may contain communications circuitry for communicating with system control circuitry over signal path  24 . Path  24  may be formed from traces on a flexible printed circuit or other cable. The control circuitry may be located on one or more printed circuits in electronic device  10 . During operation, control circuitry (e.g., control circuitry  16  of  FIG.  1   ) may supply circuitry such as a display driver integrated circuit in circuitry  20  with image data for images to be displayed on display  14 . Display driver circuitry  20 A of  FIG.  2    is located at the top of display  14 . This is merely illustrative. Display driver circuitry  20 A may be located at both the top and bottom of display  14  or in other portions of device  10 . 
     To display the images on pixels  22 , display driver circuitry  20 A may supply corresponding image data to data lines D while issuing control signals to supporting display driver circuitry such as gate driver circuitry  20 B over signal paths  30 . With the illustrative arrangement of  FIG.  2   , data lines D run vertically through display  14  and are associated with respective columns of pixels  22 . 
     Gate driver circuitry  20 B (sometimes referred to as gate line driver circuitry or horizontal control signal circuitry) may be implemented using one or more integrated circuits and/or may be implemented using thin-film transistor circuitry on substrate  26 . Horizontal control lines G (sometimes referred to as gate lines, scan lines, emission control lines, etc.) run horizontally across display  14 . Each gate line G is associated with a respective row of pixels  22 . If desired, there may be multiple horizontal control lines such as gate lines G associated with each row of pixels. Individually controlled and/or global signal paths in display  14  may also be used to distribute other signals (e.g., power supply signals, etc.). 
     Gate driver circuitry  20 B may assert control signals on the gate lines G in display  14 . For example, gate driver circuitry  20 B may receive clock signals and other control signals from circuitry  20 A on paths  30  and may, in response to the received signals, assert a gate line signal on gate lines G in sequence, starting with the gate line signal G in the first row of pixels  22  in array  28 . As each gate line is asserted, data from data lines D may be loaded into a corresponding row of pixels. In this way, control circuitry such as display driver circuitry  20 A and  20 B may provide pixels  22  with signals that direct pixels  22  to display a desired image on display  14 . Each pixel  22  may have a light-emitting diode and circuitry (e.g., thin-film circuitry on substrate  26 ) that responds to the control and data signals from display driver circuitry  20 . 
     Gate driver circuitry  20 B may include blocks of gate driver circuitry such as gate driver row blocks. Each gate driver row block may include circuitry such output buffers and other output driver circuitry, register circuits (e.g., registers that can be chained together to form a shift register), and signal lines, power lines, and other interconnects. Each gate driver row block may supply one or more gate signals to one or more respective gate lines in a corresponding row of the pixels of the array of pixels in the active area of display  14 . 
       FIG.  3    is a cross-sectional side view of an illustrative display. The display may include a substrate  26  formed from silicon. The silicon substrate may include circuitry (transistors) that is used to operate pixels  22 . Using silicon as the material for substrate  26  may allow for display  14  to have a higher resolution and/or greater processing capabilities than if a different material such as glass or plastic is used for substrate  26 . 
     Substrate  26  may include a plurality of contacts that are used to electrically connect circuitry within the substrate to additional components within the electronic device. One such contact is cathode contact  58 . Cathode contact  58  is configured to electrically connect to a cathode layer for the display. The cathode layer may be present when display  14  includes organic light-emitting diode pixels, as an example. In an organic light-emitting diode display, organic light-emitting diode layers may be formed over substrate  26 . Substrate  26  may include an array of anodes that contact the organic light-emitting diode layers. The cathode layer is formed over the organic light-emitting diode layers. 
     In the example of  FIG.  3   , a display driver integrated circuit (DDIC)  50  is included in the electronic device. The display driver integrated circuit  50  includes display driver circuitry for the display such as display driver circuitry  20 A in  FIG.  2   . Display driver integrated circuit  50  is configured to provide data and other control signals to display  14  to control operations of pixels  22 . 
     As shown in  FIG.  3   , display driver integrated circuit  50  may be mounted (attached) directly to silicon substrate  26 . Display driver integrated circuit  50  includes contacts  52  (sometimes referred to as contact pads  52 ) that are configured to electrically connect to contacts  56  (sometimes referred to as contact pads  56  or bond pads  56 ) in substrate  26 . Contacts  52  of display driver integrated circuit  50  may be bonded to contacts  56  of substrate  26  using conductive bonding structures  54  (sometimes referred to as conductive interconnect structures  54 , conductive attachment structures  54 , etc.). Conductive bonding structures  54  may be, for example, formed from anisotropic conductive films (ACF). A conductive bonding structure  54  is interposed between each respective contact  52  and contact  56 . Conductive bonding structures  54  are used to bond DDIC  50  to substrate  26 . The conductive bonding structures may form a physical and electrical connection between DDIC  50  and substrate  26 . 
     Display driver integrated circuit  50  may receive signals from flexible printed circuit  60 . The flexible printed circuit  60  may be coupled between substrate layer  26  and printed circuit board  74 . Flexible printed circuit  60  may be formed from one or more dielectric layers formed from a flexible material such as polyimide. Metal traces may be printed on the one or more dielectric layers. Printed circuit board  74  may be, for example, a rigid printed circuit board (sometimes referred to as a motherboard). 
     Flexible printed circuit  60  includes one or more contacts  62  (sometimes referred to as contact pads  62 ) and one or more contacts  68  (sometimes referred to as contact pads  68 ). Contacts  62  are electrically connected to a respective contact  66  (sometimes referred to as contact pads  66  or bond pads  66 ) in substrate  26  by conductive bonding structures  64  (sometimes referred to as conductive interconnect structures  64 , conductive attachment structures  64 , etc.). Contacts  68  are electrically connected to a respective contact  72  (sometimes referred to as contact pads  72  or bond pads  72 ) in rigid printed circuit board  74  by conductive bonding structures  70  (sometimes referred to as conductive interconnect structures  70 , conductive attachment structures  70 , etc.). Conductive bonding structures  64  and  70  may be, for example, formed from anisotropic conductive films. A conductive bonding structure  64  is interposed between each respective contact  62  and contact  66 . The conductive bonding structures  64  may form a physical and electrical connection between flexible printed circuit  60  and substrate  26 . A conductive bonding structure  70  is interposed between each respective contact  68  and contact  72 . The conductive bonding structures  70  may form a physical and electrical connection between flexible printed circuit  60  and rigid printed circuit board  74 . 
     During operations of the electronic device of  FIG.  3   , signals for operating the display (e.g., control signals and/or display data) may be provided from control circuitry within rigid printed circuit board  74  to flexible printed circuit  60 . The flexible printed circuit  60  conveys the signals to substrate  26  (e.g., to contact pads  66 ). Thereafter, display driver integrated circuit  50  receives the signals from substrate  26  (e.g., from some of the contact pads  56 ). Display driver integrated circuit  50  may output corresponding signals for operating the display to substrate  26  (e.g., to some of the contact pads  56 ). The signals from display driver integrated circuit  50  may subsequently be used by circuitry within substrate  26  to operate the display. 
     In  FIG.  3   , display driver integrated circuit  50  completely overlaps silicon layer  26 . Accordingly, the footprint of silicon layer  26  needs to be sufficiently large to accommodate the footprint of display driver integrated circuit  50 . As shown in  FIG.  3   , there is a distance  78  between the edge of the pixel array (e.g., a light-emitting active area for the display) and an edge of substrate  26 . In  FIG.  3   , distance  78  needs to be sufficiently large to accommodate cathode contact  58 , contact pads  56  that couple to the display driver integrated circuit that completely overlaps the substrate, and contact pads  66  that couple to the flexible printed circuit that partially overlaps the substrate. 
     It may be desirable to reduce the magnitude of distance  78 . Because substrate  26  in  FIG.  3    is formed from silicon, substrate  26  may be formed using a semiconductor manufacturing process. In the semiconductor manufacturing process, numerous silicon dice are formed in a larger silicon wafer. The silicon wafer is then diced to produce the individual silicon layers  26  that are of the appropriate size for display  14 . There may be limits to the size of the silicon wafer that can be produced during the semiconductor manufacturing process. Accordingly, the larger the footprint of substrate  26  for display  14 , the fewer silicon dice can be fit on the silicon wafer during manufacturing. To increase the number of silicon dice that fit on the silicon wafer during manufacturing, the footprint of substrate  26  may be decreased. 
       FIG.  4    is a cross-sectional side view of an illustrative display that uses an interposer to decrease the size of the footprint of substrate  26 . In  FIG.  4   , the display may include a substrate  26  formed from silicon. The silicon substrate may include circuitry (transistors) that is used to operate pixels  22 . Using silicon as the material for substrate  26  may allow for display  14  to have a higher resolution and/or greater processing capabilities than if a different material such as glass or plastic is used for substrate  26 . 
     Substrate  26  may include a plurality of contacts that are used to electrically connect circuitry within the substrate to additional components within the electronic device. One such contact is cathode contact  58 . Cathode contact  58  is configured to electrically connect to a cathode layer for the display. The cathode layer may be used when display  14  includes organic light-emitting diode pixels, as previously described. 
     In the example of  FIG.  4   , display driver integrated circuit (DDIC)  50  is mounted on (attached to) an interposer  76 . Display driver integrated circuit  50  includes display driver circuitry for the display such as display driver circuitry  20 A in  FIG.  2   . Display driver integrated circuit  50  is configured to provide data and other control signals to display  14  to control operations of pixels  22 . 
     As shown in  FIG.  3   , display driver integrated circuit  50  may be mounted directly on (bonded to) interposer  76 . Interposer  76  may be formed from silicon or another desired material. Display driver integrated circuit  50  includes contacts  52  (sometimes referred to as contact pads  52 ) that are configured to electrically connect to contacts  84  (sometimes referred to as contact pads  84  or bond pads  84 ) in interposer  76 . Contacts  52  of display driver integrated circuit  50  may be bonded to contacts  84  of interposer  76  using conductive bonding structures  54  (sometimes referred to as conductive interconnect structures  54 , conductive attachment structures  54 , etc.). Conductive bonding structures  54  may be, for example, formed from anisotropic conductive films or solder. A conductive bonding structure  54  is interposed between each respective contact  52  and contact  84 . The conductive bonding structures  54  may form a physical and electrical connection between DDIC  50  and interposer  76 . 
     Interposer  76  may receive signals from flexible printed circuit  60 . The flexible printed circuit  60  may be coupled between interposer  76  and printed circuit board  74 . Flexible printed circuit  60  includes one or more contacts  62  (sometimes referred to as contact pads  62 ) and one or more contacts  68  (sometimes referred to as contact pads  68 ). Contacts  62  are electrically connected to a respective contact  82  (sometimes referred to as contact pads  82  or bond pads  82 ) in interposer  76  by conductive bonding structures  64  (sometimes referred to as conductive interconnect structures  64 , conductive attachment structures  64 , etc.). Contacts  68  are electrically connected to a respective contact  72  (sometimes referred to as contact pads  72  or bond pads  72 ) in rigid printed circuit board  74  by conductive bonding structures  70  (sometimes referred to as conductive interconnect structures  70 , conductive attachment structures  70 , etc.). Conductive bonding structures  64  and  70  may be, for example, formed from anisotropic conductive films. A conductive bonding structure  64  is interposed between each respective contact  62  and contact  82 . The conductive bonding structures  64  may form a physical and electrical connection between flexible printed circuit  60  and interposer  76 . A conductive bonding structure  70  is interposed between each respective contact  68  and contact  72 . The conductive bonding structures  70  may form a physical and electrical connection between flexible printed circuit  60  and rigid printed circuit board  74 . 
     Interposer  76  may have a portion mounted on substrate  26 . As shown in  FIG.  4   , interposer  76  includes contacts  86  (sometimes referred to as contact pads  86 ) that are configured to electrically connect to contacts  56  (sometimes referred to as contact pads  56  or bond pads  56 ) in substrate  26 . Contacts  86  of interposer  76  may be bonded to contacts  56  of substrate  26  using conductive bonding structures  88  (sometimes referred to as conductive interconnect structures  88 , conductive attachment structures  88 , etc.). Conductive bonding structures  88  may be, for example, formed from anisotropic conductive films. A conductive bonding structure  88  is interposed between each respective contact  86  and contact  56 . The conductive bonding structures  88  may form a physical and electrical connection between interposer  76  and substrate  26 . 
     There may be an array of contacts  56  that are configured to be electrically connected to the interposer contacts  86  using conductive structures  88 . There may be more than 1,000 total contacts  56 , more than 3,000 total contacts  56 , more than 5,000 total contacts  56 , more than 7,000 total contacts  56 , more than 8,000 total contacts  56 , more than 9,000 total contacts  56 , etc. The array of contacts  56  may have more than five rows, more than ten rows, more than twenty rows, more than thirty rows, etc. The array of contacts  56  may have more than 100 columns, more than 200 columns, more than 300 columns, more than 400 columns, etc. 
     During operations of the electronic device of  FIG.  4   , signals for operating the display (e.g., control signals and/or display data) may be provided from control circuitry within rigid printed circuit board  74  to flexible printed circuit  60 . The flexible printed circuit  60  conveys the signals to interposer  76  (e.g., to contact pads  82 ). Thereafter, display driver integrated circuit  50  receives the signals from interposer  76  (e.g., from some of the contact pads  84  in interposer  76 ). Display driver integrated circuit  50  may output corresponding signals for operating the display to interposer  76  (e.g., to some of the contact pads  84  in interposer  76 ). Thereafter, the signals are conveyed from the interposer  76  to substrate  26  (e.g., to contact pads  56 ). The signals may subsequently be used by circuitry within substrate  26  to operate the display. 
     Interposer  76  therefore receive signals from the flexible printed circuit (e.g., at contacts  82 ), conveys the signals to DDIC  50  (e.g., using some of contacts  84 ), receives output signals from DDIC  50  (e.g., at some of contacts  84 ), and conveys the signals to substrate  26  (e.g., using contacts  86 ). 
     In  FIG.  3   , contacts are needed in substrate  26  to both provide signals to DDIC  50  and receive signals from DDIC  50 . In  FIG.  4   , contacts are only needed to receive signals from DDIC  50  (from intervening interposer  76 ). 
     In  FIG.  3   , a contact  66  is present in substrate  26  to electrically connect to the flexible printed circuit  60 . In  FIG.  4   , this contact is omitted (and instead the flexible printed circuit is connected to interposer  76 ). 
     Due to the omission of these components on substrate  26  in  FIG.  4   , the footprint of silicon layer  26  in  FIG.  4    only needs to be sufficiently large to accommodate the partial footprint of interposer  76 . In  FIG.  4   , display driver integrated circuit  50  does not overlap silicon layer  26 . Interposer  76  only partially overlaps silicon layer  26 . As shown in  FIG.  4   , there is a distance  78  between the edge of the pixel array (e.g., a light-emitting active area for the display) and an edge of substrate  26 . In  FIG.  4   , distance  78  needs to be sufficiently large to accommodate cathode contact  58  and contact pads  56  that couple to the interposer that partially overlaps the substrate. Distance  78  in  FIG.  4    is less than distance  78  in  FIG.  3    due to the space saved by omitting the contact pads for the flexible printed circuit (e.g., contacts  66  in  FIG.  3   ) and by omitting some of contacts  56  for the display driver integrated circuit. 
     Distance  78  in  FIG.  4    may be less than 10 millimeters, less than 5 millimeters, less than 3 millimeters, less than 2 millimeters, less than 1 millimeter, greater than 1 millimeter, between 2 millimeters and 5 millimeters, etc. The smaller footprint of substrate  26  in  FIG.  4    relative to  FIG.  3    allows for more silicon dice to fit on a silicon wafer during manufacturing. 
     To ensure the mechanical reliability of the interposer  76  and DDIC  50  in  FIG.  4   , a support structure extension may be present. As shown in  FIG.  4   , a support structure  90  may be present below substrate  26 . Support structure  90  may physically support substrate  26  within the electronic device. Support structure  90  may also be formed from a thermally conductive material and therefore serve as a heat sink for substrate  26 . Support structure  90  may therefore sometimes be referred to as heat sink structure  90  or heat sink  90 . Support structure  90  may have a thermal conductivity (in units of W×m −1 ×K −1 ) that is greater than 50, greater than 100, greater than 200, greater than 300, greater than 400, greater than 500, etc. 
     As shown in  FIG.  4   , support structure  90  may have an extension  102  that extends past an edge of substrate  26 . Extension  102  may be formed under display driver integrated circuit  50  and a corresponding overlapped portion of interposer  76 . In this way, extension  102  is in a position to provide mechanical support to display driver integrated circuit  50  and interposer  76 . A filler  92  may be included between support structure  90  and display driver integrated circuit  50  and/or interposer  76 . Filler  92  may contact both support structure  90  and display driver integrated circuit  50  and/or interposer  76  to mitigate vertical deflection of display driver integrated circuit  50  and/or interposer  76  in the event of an impact event (e.g., when the device is dropped). 
     In some cases, filler  92  may be formed from a conformal material that conforms to an upper surface and edges of display driver integrated circuit  50 . The conformal material may be deposited in a liquid state to ensure the material fills the gap between support structure  90  and display driver integrated circuit  50  and conforms to display driver integrated circuit  50 . The conformal material may subsequently be solidified to ensure the material maintains its shape/structural integrity during operation. Filler  92  in this type of arrangement may be epoxy, as an example. 
     In another possible example, filler  92  may be formed from a solid plastic spacer that is attached to support structure  90  and/or display driver integrated circuit  50  with adhesive. In this case, the filler is attached in a solid state and serves as a spacer between support structure  90  and display driver integrated circuit  50  and/or interposer  76 . 
     Using interposer  76  in device  10  provides advantages in addition to reducing the footprint of substrate  26 . Bonding processes for contacts on substrate  26  may be temperature limited due to manufacturing constraints associated with the silicon substrate. Due to these temperature constraints, soldering may not be available as an attachment technique for contacts on substrate  26 . This is why anisotropic conductive films (ACF) may be used as the attachment structure for contacts on substrate  26 . 
     With the arrangement of  FIG.  3   , where display driver integrated circuit  50  is attached directly to the substrate  26 , solder is not available as an attachment structure between display driver integrated circuit  50  and substrate  26  due to the temperature constraints. However, in  FIG.  4   , where display driver integrated circuit  50  is attached to interposer  76 , the display driver integrated circuit to interposer bonds may be made before the module is attached to substrate  26 . Therefore, the display driver integrated circuit to interposer bonds may be made using a higher temperature process (e.g., soldering). 
     Said another way, in  FIG.  4   , conductive bonding structures  54  (between interposer  76  and DDIC  50 ) may have a higher melting point than conductive bonding structures  88  (between interposer  76  and substrate  26 ). Conductive bonding structures  54  may be formed from solder while conductive bonding structures  88  may be formed from ACF. 
     Another advantage to using interposer  76  in device  10  is that interposer  76  may be designed to include additional circuitry  80  for the electronic device. Additional circuitry  80  may be timing circuitry for operating the display (e.g., gate driver circuitry  20 B as in  FIG.  2   ), power delivery circuitry for delivering power to the display, or any other desired circuitry. Including timing circuitry (e.g., gate driver circuitry  20 B in  FIG.  2   ) in interposer  76  allows for the timing circuitry to be removed from substrate  26 , further reducing the footprint requirements for substrate  26 . Power delivery circuitry may sometimes be included in rigid printed circuit board  74 . Moving the power delivery circuitry from rigid printed circuit board  74  to interposer  76  results in the power delivery circuitry being closer to substrate  26 , offering performance improvements. 
     The example of including a dedicated interposer structure as in  FIG.  4    is merely illustrative. In another possible arrangement, shown in  FIG.  5   , display driver integrated circuit  50  may itself serve as interposer that bridges a gap between flexible printed circuit  60  and substrate  26 . Display driver integrated circuit  50  includes contacts  52  (sometimes referred to as contact pads  52 ). Some of the contacts  52  are configured to electrically connect to contacts  56  (sometimes referred to as contact pads  56  or bond pads  56 ) in substrate  26 . Contacts  52  of display driver integrated circuit  50  may be bonded to contacts  56  of substrate  26  using conductive bonding structures  54  (sometimes referred to as conductive interconnect structures  54 , conductive attachment structures  54 , etc.). Conductive bonding structures  54  may be, for example, formed from anisotropic conductive films (ACF). A conductive bonding structure  54  is interposed between each respective contact  52  and contact  56 . The conductive bonding structures  54  may form a physical and electrical connection between DDIC  50  and substrate  26 . 
     There may be an array of contacts  56  that are configured to be electrically connected to the DDIC contacts  52  using conductive structures  54 . There may be more than 1,000 total contacts  56 , more than 3,000 total contacts  56 , more than 5,000 total contacts  56 , more than 7,000 total contacts  56 , more than 8,000 total contacts  56 , more than 9,000 total contacts  56 , etc. The array of contacts  56  may have more than five rows, more than ten rows, more than twenty rows, more than thirty rows, etc. The array of contacts  56  may have more than 100 columns, more than 200 columns, more than 300 columns, more than 400 columns, etc. 
     Display driver integrated circuit  50  may receive signals from flexible printed circuit  60 . The flexible printed circuit  60  may be coupled directly to contacts  52  in display driver integrated circuit  50 . 
     Flexible printed circuit  60  includes one or more contacts  96  (sometimes referred to as contact pads  96 ) and one or more contacts  68  (sometimes referred to as contact pads  68 ). Contacts  96  are electrically connected to a respective contact  52  (sometimes referred to as contact pads  52  or bond pads  52 ) in DDIC  50  by conductive bonding structures  98  (sometimes referred to as conductive interconnect structures  98 , conductive attachment structures  98 , etc.). Contacts  68  are electrically connected to a respective contact  72  (sometimes referred to as contact pads  72  or bond pads  72 ) in rigid printed circuit board  74  by conductive bonding structures  70  (sometimes referred to as conductive interconnect structures  70 , conductive attachment structures  70 , etc.). Conductive bonding structures  70  and  98  may be, for example, formed from anisotropic conductive films. A conductive bonding structure  98  is interposed between each respective contact  96  and contact  52 . The conductive bonding structures  98  may form a physical and electrical connection between flexible printed circuit  60  and DDIC  50 . A conductive bonding structure  70  is interposed between each respective contact  68  and contact  72 . The conductive bonding structures  70  may form a physical and electrical connection between flexible printed circuit  60  and rigid printed circuit board  74 . 
     During operations of the electronic device of  FIG.  5   , signals for operating the display (e.g., control signals and/or display data) may be provided from control circuitry within rigid printed circuit board  74  to flexible printed circuit  60 . The flexible printed circuit  60  conveys the signals to DDIC  50  (e.g., to some of contact pads  52 ). Thereafter, display driver integrated circuit  50  may output corresponding signals for operating the display to substrate  26  (e.g., to the contact pads  56 ). The signals from display driver integrated circuit  50  may subsequently be used by circuitry within substrate  26  to operate the display. 
     In  FIG.  3   , contacts are needed in substrate  26  to both provide signals to DDIC  50  and receive signals from DDIC  50 . In  FIG.  5   , contacts are only needed to receive signals from DDIC  50 . 
     In  FIG.  3   , a contact  66  is present in substrate  26  to electrically connect to the flexible printed circuit  60 . In  FIG.  5   , this contact is omitted (and instead the flexible printed circuit is connected to DDIC  50 ). 
     Due to the omission of these components on substrate  26  in  FIG.  5   , the footprint of silicon layer  26  in  FIG.  5    only needs to be sufficiently large to accommodate the partial footprint of DDIC  50 . In  FIG.  5   , display driver integrated circuit  50  only partially overlaps silicon layer  26 . As shown in  FIG.  5   , there is a distance  78  between the edge of the pixel array (e.g., a light-emitting active area for the display) and an edge of substrate  26 . In  FIG.  5   , distance  78  needs to be sufficiently large to accommodate cathode contact  58  and contact pads  56  that couple to the DDIC  50 . Distance  78  in  FIG.  5    is less than distance  78  in  FIG.  3    due to the space saved by omitting the contact pad for the flexible printed circuit (e.g., contact  66  in  FIG.  3   ) and by omitting some of contacts  56  for the display driver integrated circuit. 
     Distance  78  in  FIG.  5    may be less than 10 millimeters, less than 5 millimeters, less than 3 millimeters, less than 2 millimeters, less than 1 millimeter, greater than 1 millimeter, between 2 millimeters and 5 millimeters, etc. The smaller footprint of substrate  26  in  FIG.  5    relative to  FIG.  3    allows for more silicon dice to fit on a silicon wafer during manufacturing. 
     To ensure the mechanical reliability of DDIC  50  in  FIG.  5   , a support structure extension may be present. As shown in  FIG.  5   , a support structure  90  may be present below substrate  26 . Support structure  90  may physically support substrate  26  within the electronic device. Support structure  90  may also be formed from a thermally conductive material and therefore serve as a heat sink for substrate  26 . Support structure  90  may therefore sometimes be referred to as heat sink structure  90  or heat sink  90 . Support structure  90  may have a thermal conductivity (in units of W×m −1 ×K −1 ) that is greater than 50, greater than 100, greater than 200, greater than 300, greater than 400, greater than 500, etc. 
     As shown in  FIG.  5   , support structure  90  may have an extension  102  that extends past an edge of substrate  26 . Extension  102  may be formed under a portion of display driver integrated circuit  50 . In this way, extension  102  is in a position to provide mechanical support to display driver integrated circuit  50 . A filler  92  may be included between support structure  90  and display driver integrated circuit  50 . Filler  92  may contact both support structure  90  and display driver integrated circuit  50  to mitigate vertical deflection of display driver integrated circuit  50  in the event of an impact event (e.g., when the device is dropped). 
     As previously discussed in connection with  FIG.  4   , filler  92  may be formed from a liquid-dispensed material that conforms to DDIC  50  or a solid structure that is attached using adhesive.  FIG.  5    shows an example of the latter arrangement, with filler  92  attached to an upper surface of support structure  90  with a first adhesive layer  94  and attached to a lower surface of DDIC  50  with a second adhesive layer  94 . 
     Although the aforementioned arrangements for the display driver integrated circuit have been described in relation to an organic light-emitting diode display, it should be noted that the aforementioned arrangements may be used for any desired display type (a microLED display, a liquid crystal display, etc.). 
     It should be noted that the example in  FIGS.  3 - 5    of flexible printed circuit  60  being bent is merely illustrative. In some cases, flexible printed circuit  60  may not be bent. In general, flexible printed circuit  60  may have any desired shape and bending profile. Moreover, flexible printed circuit does not necessarily need to be bonded to rigid printed circuit board  74  (e.g., using structures  68 ,  70 , and  72 ). Other arrangements may be used if desired. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20220526
Publication Date: 20241008
Grant Date: 20241008
Priority Date: 20210902
Inventors: SCARDATO, STEVEN M
CAGDASER, BARIS
BENNETT, PATRICK B
SLOOTSKY, MICHAEL
LEVANDER, ALEJANDRO X
JEN, HENRY C
Assignee: APPLE INC
CPC Classifications: [{"code": "G09G2300/0426", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2300/0408", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2380/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2330/045", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2300/0426", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/2092", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G3/2092", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2300/0426", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2300/0408", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/2092", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 85289002