PATENT DOCUMENT

Publication Number: US-10031367-B2
Application Number: US-201213628811-A
Country: US
Kind Code: B2

Title: Display with inverted thin-film-transistor layer

Abstract:
An electronic device may be provided with a display that has a layer of liquid crystal material interposed between a color filter layer and a thin-film-transistor layer. The thin-film-transistor layer may have a substrate with an upper surface and a lower surface. A circular polarizer may be formed on the upper surface. Thin-film transistor circuitry such as gate driver circuitry may be formed on the lower surface. A display driver circuit may be mounted on an inactive border region of the lower surface of the thin-film transistor substrate. Display pixels may form an array in a central active region of the display. A grid of metal gate and data lines may distribute signals from the display driver circuit and gate driver circuitry to the display pixels. A grid of non-reflecting lines may be interposed between the grid of metal lines and the lower surface.

Claims:
What is claimed is: 
     
       1. A display having an active area surrounded by an inactive border area, comprising:
 a polarizer; 
 a thin-film transistor layer that includes a thin-film-transistor substrate layer, an array of display pixels on the thin-film-transistor substrate layer, and a grid of metal data and gate lines that distribute signals to the display pixels, wherein the thin-film transistor layer further includes a non-reflecting material that is formed between the grid of metal data and gate lines and the thin-film transistor substrate layer, wherein the thin-film transistor substrate layer is interposed between the non-reflecting material and the polarizer, and wherein the non-reflecting material extends into the inactive border area to form an opaque border; and 
 a liquid crystal layer, wherein the thin-film-transistor layer is interposed between the polarizer and the liquid crystal layer. 
 
     
     
       2. The display defined in  claim 1  wherein the polarizer is a circular polarizer. 
     
     
       3. The display defined in  claim 1  wherein the non-reflecting material is characterized by a reflectance of less than 20%. 
     
     
       4. The display defined in  claim 1  wherein the non-reflecting material comprises an inorganic material. 
     
     
       5. The display defined in  claim 4  wherein the non-reflecting material includes multiple sublayers. 
     
     
       6. The display defined in  claim 5  wherein the non-reflecting material includes a chrome layer and a layer of chromium oxide and wherein the chromium oxide is interposed between the chrome layer and the thin-film-transistor substrate layer. 
     
     
       7. The display defined in  claim 4  wherein the non-reflecting material comprises chromium oxide. 
     
     
       8. The display defined in  claim 7  wherein the metal lines comprise metal lines selected from the group consisting of: aluminum lines, molybdenum lines, chromium lines, and copper lines. 
     
     
       9. The display defined in  claim 8  wherein the polarizer is a circular polarizer. 
     
     
       10. The display defined in  claim 8  further comprising:
 a color filter layer; 
 an additional polarizer; and 
 a light guide plate, wherein the color filter layer is interposed between the additional polarizer and the liquid crystal layer and wherein the additional polarizer is interposed between light guide plate and the color filter layer. 
 
     
     
       11. The display defined in  claim 1  wherein the non-reflecting material comprises an organic material. 
     
     
       12. The display defined in  claim 11  wherein the non-reflecting material is configured to exhibit a reflectance of less than 20%. 
     
     
       13. The display defined in  claim 1  further comprising:
 a light guide plate that distributes backlight; 
 a color filter layer; and 
 an additional polarizer, wherein the color filter layer is interposed between the additional polarizer and the liquid crystal layer and wherein the additional polarizer is interposed between light guide plate and the color filter layer. 
 
     
     
       14. The display defined in  claim 1  further comprising:
 a color filter layer, wherein the liquid crystal layer is interposed between the color filter layer and the thin-film-transistor layer; 
 sealant that is formed between the color filter layer and liquid crystal layer and that surrounds the liquid crystal layer to contain the liquid crystal layer, wherein the opaque border overlaps the sealant in the inactive border area. 
 
     
     
       15. A display comprising:
 an upper polarizer; 
 a lower polarizer; 
 a liquid crystal layer; 
 a thin-film transistor layer between the upper polarizer layer and the liquid crystal layer; 
 a color filter layer between the lower polarizer and the liquid crystal layer; 
 a backlight structure, wherein the lower polarizer is interposed between the color filter layer and the backlight structure; 
 at least one integrated circuit mounted to the thin-film transistor layer, wherein the thin-film transistor layer comprises:
 a thin-film-transistor substrate layer; 
 gate driver circuitry on the thin-film transistor substrate layer; 
 display pixels on the thin-film transistor substrate layer; 
 a grid of crisscrossed metal gate and data lines on the thin-film transistor substrate layer that distribute signals to the display pixels from the gate driver circuitry and the integrated circuit; 
 a grid of crisscrossed lines of non-reflecting material interposed between the grid of crisscrossed metal gate and data lines and the thin-film transistor substrate layer, wherein the grid of non-reflecting material extends into an inactive region of the display to form an opaque border in the inactive region of the display, and wherein the opaque border overlaps the at least one integrated circuit to hide the at least one integrated circuit from view. 
 
 
     
     
       16. The display defined in  claim 15 , comprising:
 sealant that surrounds the liquid crystal layer and that is interposed between the thin-film transistor layer and the color filter layer, wherein the opaque border overlaps the sealant to hide the sealant from view. 
 
     
     
       17. The display defined in  claim 16  wherein the upper polarizer comprises a circular polarizer. 
     
     
       18. The display defined in  claim 17  wherein the grid of crisscrossed lines of non-reflecting material comprises an inorganic material. 
     
     
       19. The display defined in  claim 18  wherein the inorganic material is configured to exhibit a visible light reflectance of less than 20%. 
     
     
       20. The display defined in  claim 19  wherein the inorganic material comprises chromium oxide. 
     
     
       21. The display defined in  claim 17  wherein the grid of crisscrossed lines of non-reflecting material comprises polymer. 
     
     
       22. A display, comprising:
 a thin-film transistor layer having a substrate with opposing first and second surfaces, having a grid of non-reflecting lines on the second surface, and having metal gate and data lines on the grid of non-reflecting lines; 
 a circular polarizer on the first surface; 
 a color filter layer; 
 a liquid crystal layer between the thin-film transistor layer and the color filter layer; and 
 an opaque masking layer interposed between the substrate and the metal gate and data lines in an inactive border region of the display, wherein the metal gate and data lines are interposed between the liquid crystal layer and the second surface of the substrate. 
 
     
     
       23. The display defined in  claim 22  wherein the grid of non-reflecting lines comprises chromium oxide. 
     
     
       24. The display defined in  claim 23  wherein the grid of non-reflecting lines comprises first and second inorganic sublayers. 
     
     
       25. The display defined in  claim 22  further comprising:
 an integrated circuit on the opaque masking layer, wherein a portion of the circular polarizer overlaps the opaque masking layer, and wherein the opaque masking layer is formed on the second surface of the substrate.

Description:
BACKGROUND 
     This relates generally to electronic devices, and more particularly, to electronic devices with displays. 
     Electronic devices often include displays. For example, cellular telephones and portable computers often include displays for presenting information to a user. An electronic device may have a housing such as a housing formed from plastic or metal. Components for the electronic device such as display components may be mounted in the housing. 
     It can be challenging to incorporate a display into the housing of an electronic device. Size and weight are often important considerations in designing electronic devices. If care is not taken, displays may be bulky or may be surrounded by overly large borders. 
     It would therefore be desirable to be able to provide improved ways to provide displays for electronic devices. 
     SUMMARY 
     An electronic device may be provided with a display such as a liquid crystal display. The liquid crystal display may have an upper polarizer and a lower polarizer. The upper polarizer may be a circular polarizer. The upper polarizer may be formed on an upper surface of a thin-film-transistor layer. The lower polarizer may be formed on a lower surface of a color filter layer. Liquid crystal material may be interposed between the thin-film-transistor layer and the color filter layer. 
     The thin-film-transistor layer may have a substrate with an upper surface and a lower surface. The circular polarizer may be formed on the upper surface of the substrate. Thin-film transistor circuitry such as gate driver circuitry may be formed on the lower surface of the substrate. An integrated circuit such as a display driver circuit may be mounted on an inactive border region of the lower surface of the thin-film transistor substrate. 
     Display pixels may form an array on the thin-film-transistor substrate. A grid of metal gate and data lines may distribute signals from the display driver circuit and gate driver circuitry to the array of display pixels. A grid of non-reflecting material may be interposed between the grid of metal lines and the lower surface. The non-reflecting material may be an organic material or may be an inorganic material and may minimize metal line reflections visible from the top of the display. 
     An opaque masking layer may be formed around a peripheral portion of the thin-film-transistor substrate, overlapping a ring of sealant that is used to contain the liquid crystal material and overlapping the display driver integrated circuit. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device such as a laptop computer with a display in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view of an illustrative electronic device such as a handheld electronic device with a display in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view of an illustrative electronic device such as a tablet computer with a display in accordance with an embodiment of the present invention. 
         FIG. 4  is a schematic diagram of an illustrative electronic device with a display in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an illustrative display in accordance with an embodiment of the present invention. 
         FIG. 6  is a perspective view of an illustrative thin-film transistor layer in accordance with an embodiment of the present invention. 
         FIG. 7  is in a cross-sectional side view of an illustrative display with an inverted thin-film-transistor layer in accordance with an embodiment of the present invention. 
         FIG. 8  is a top view of an illustrative display showing how an inactive border region may be provided with an opaque masking material in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional side view of a thin-film transistor layer that has been provided with a patterned non-reflecting layer to help hide internal components from view in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may include displays. The displays may be used to display images to a user. Illustrative electronic devices that may be provided with displays are shown in  FIGS. 1, 2, and 3 . 
       FIG. 1  shows how electronic device  10  may have the shape of a laptop computer having upper housing  12 A and lower housing  12 B with components such as keyboard  16  and touchpad  18 . Device  10  may have hinge structures  20  that allow upper housing  12 A to rotate in directions  22  about rotational axis  24  relative to lower housing  12 B. Display  14  may be mounted in upper housing  12 A. Upper housing  12 A, which may sometimes referred to as a display housing or lid, may be placed in a closed position by rotating upper housing  12 A towards lower housing  12 B about rotational axis  24 . 
       FIG. 2  shows how electronic device  10  may be a handheld device such as a cellular telephone, music player, gaming device, navigation unit, or other compact device. In this type of configuration for device  10 , housing  12  may have opposing front and rear surfaces. Display  14  may be mounted on a front face of housing  12 . Display  14  may, if desired, have a display cover layer or other exterior layer that includes openings for components such as button  26 . Openings may also be formed in a display cover layer or other display layer to accommodate a speaker port (see, e.g., speaker port  28  of  FIG. 2 ). 
       FIG. 3  shows how electronic device  10  may be a tablet computer. In electronic device  10  of  FIG. 3 , housing  12  may have opposing planar front and rear surfaces. Display  14  may be mounted on the front surface of housing  12 . As shown in  FIG. 3 , display  14  may have a cover layer or other external layer (e.g., a color filter layer or thin-film-transistor layer) with an opening to accommodate button  26  (as an example). 
     The illustrative configurations for device  10  that are shown in  FIGS. 1, 2, and 3  are merely illustrative. In general, electronic device  10  may be 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, or other wearable or miniature device, a television, 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, equipment that implements the functionality of two or more of these devices, or other electronic equipment. 
     Housing  12  of device  10 , which is sometimes referred to as a case, may be formed of materials such as plastic, glass, ceramics, carbon-fiber composites and other fiber-based composites, metal (e.g., machined aluminum, stainless steel, or other metals), other materials, or a combination of these materials. Device  10  may be formed using a unibody construction in which most or all of housing  12  is formed from a single structural element (e.g., a piece of machined metal or a piece of molded plastic) or may be formed from multiple housing structures (e.g., outer housing structures that have been mounted to internal frame elements or other internal housing structures). 
     Display  14  may be a touch sensitive display that includes a touch sensor or may be insensitive to touch. Touch sensors for display  14  may be formed from an array of capacitive touch sensor electrodes, a resistive touch array, touch sensor structures based on acoustic touch, optical touch, or force-based touch technologies, or other suitable touch sensor components. 
     Displays for device  10  may, in general, include image pixels formed from light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electrowetting pixels, electrophoretic pixels, liquid crystal display (LCD) components, or other suitable image pixel structures. In some situations, it may be desirable to use LCD components to form display  14 , so configurations for display  14  in which display  14  is a liquid crystal display are sometimes described herein as an example. It may also be desirable to provide displays such as display  14  with backlight structures, so configurations for display  14  that include a backlight unit may sometimes be described herein as an example. Other types of display technology may be used in device  10  if desired. The use of liquid crystal display structures and backlight structures in device  10  is merely illustrative. 
     A display cover layer may cover the surface of display  14  or a display layer such as a color filter layer, thin-film transistor layer or other portion of a display may be used as the outermost (or nearly outermost) layer in display  14 . For example, a color filter layer or thin-film transistor layer that is covered by a polarizer layer may form the outermost layer for device  10 . A display cover layer or other outer display layer may be formed from a transparent glass sheet, a clear plastic layer, or other transparent member. 
     Touch sensor components such as an array of capacitive touch sensor electrodes formed from transparent materials such as indium tin oxide may be formed on the underside of a display cover layer, may be formed on a separate display layer such as a glass or polymer touch sensor substrate, or may be integrated into other display layers (e.g., substrate layers such as a thin-film transistor layer). 
     A schematic diagram of an illustrative configuration that may be used for electronic device  10  is shown in  FIG. 4 . As shown in  FIG. 4 , electronic device  10  may include control circuitry  29 . Control circuitry  29  may include storage and processing circuitry for controlling the operation of device  10 . Control circuitry  29  may, for example, 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. Control circuitry  29  may include processing circuitry based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio codec chips, application specific integrated circuits, etc. 
     Control circuitry  29  may be used to run software on device  10 , such as operating system software and application software. Using this software, control circuitry  29  may present information to a user of electronic device  10  on display  14 . When presenting information to a user on display  14 , sensor signals and other information may be used by control circuitry  29  in making adjustments to the strength of backlight illumination that is used for display  14 . 
     Input-output circuitry  30  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 circuitry  30  may include communications circuitry  32 . Communications circuitry  32  may include wired communications circuitry for supporting communications using data ports in device  10 . Communications circuitry  32  may also include wireless communications circuits (e.g., circuitry for transmitting and receiving wireless radio-frequency signals using antennas). 
     Input-output circuitry  30  may also include input-output devices  34 . A user can control the operation of device  10  by supplying commands through input-output devices  34  and may receive status information and other output from device  10  using the output resources of input-output devices  34 . 
     Input-output devices  34  may include sensors and status indicators  36  such as an ambient light sensor, a proximity sensor, a temperature sensor, a pressure sensor, a magnetic sensor, an accelerometer, and light-emitting diodes and other components for gathering information about the environment in which device  10  is operating and providing information to a user of device  10  about the status of device  10 . 
     Audio components  38  may include speakers and tone generators for presenting sound to a user of device  10  and microphones for gathering user audio input. 
     Display  14  may be used to present images for a user such as text, video, and still images. Sensors  36  may include a touch sensor array that is formed as one of the layers in display  14 . 
     User input may be gathered using buttons and other input-output components  40  such as touch pad sensors, buttons, joysticks, click wheels, scrolling wheels, touch sensors such as sensors  36  in display  14 , key pads, keyboards, vibrators, cameras, and other input-output components. 
     A cross-sectional side view of an illustrative configuration that may be used for display  14  of device  10  (e.g., for display  14  of the devices of  FIG. 1 ,  FIG. 2 , or  FIG. 3  or other suitable electronic devices) is shown in  FIG. 5 . As shown in  FIG. 5 , display  14  may include backlight structures such as backlight unit  42  for producing backlight  44 . During operation, backlight  44  travels outwards (vertically upwards in dimension Z in the orientation of  FIG. 5 ) and passes through display pixel structures in display layers  46 . This illuminates any images that are being produced by the display pixels for viewing by a user. For example, backlight  44  may illuminate images on display layers  46  that are being viewed by viewer  48  in direction  50 . 
     Display layers  46  may be mounted in chassis structures such as a plastic chassis structure and/or a metal chassis structure to form a display module for mounting in housing  12  or display layers  46  may be mounted directly in housing  12  (e.g., by stacking display layers  46  into a recessed portion in housing  12 ). Display layers  46  may form a liquid crystal display or may be used in forming displays of other types. 
     In a configuration in which display layers  46  are used in forming a liquid crystal display, display layers  46  may include a liquid crystal layer such a liquid crystal layer  52 . Liquid crystal layer  52  may be sandwiched between display layers such as display layers  58  and  56 . Layers  56  and  58  may be interposed between lower polarizer layer  60  and upper polarizer layer  54 . 
     Layers  58  and  56  may be formed from transparent substrate layers such as clear layers of glass or plastic. Layers  56  and  58  may be layers such as a thin-film transistor layer and/or a color filter layer. Conductive traces, color filter elements, transistors, and other circuits and structures may be formed on the substrates of layers  58  and  56  (e.g., to form a thin-film transistor layer and/or a color filter layer). Touch sensor electrodes may also be incorporated into layers such as layers  58  and  56  and/or touch sensor electrodes may be formed on other substrates. 
     With one illustrative configuration, layer  58  may be a thin-film transistor layer that includes an array of thin-film transistors and associated electrodes (display pixel electrodes) for applying electric fields to liquid crystal layer  52  and thereby displaying images on display  14 . Layer  56  may be a color filter layer that includes an array of color filter elements for providing display  14  with the ability to display color images. If desired, the positions of color filter layer  56  and thin-film-transistor layer  58  may be inverted so that the thin-film-transistor layer is located above the color filter layer. 
     During operation of display  14  in device  10 , control circuitry  29  (e.g., one or more integrated circuits such as components  68  on printed circuit  66  of  FIG. 5 ) may be used to generate information to be displayed on display (e.g., display data). The information to be displayed may be conveyed from circuitry  68  to display driver integrated circuit  62  using a signal path such as a signal path formed from conductive metal traces in flexible printed circuit  64  (as an example). 
     Display driver integrated circuit  62  may be mounted on thin-film-transistor layer driver ledge  82  or elsewhere in device  10 . A flexible printed circuit cable such as flexible printed circuit  64  may be used in routing signals between printed circuit  66  and thin-film-transistor layer  60 . If desired, display driver integrated circuit  62  may be mounted on printed circuit  66  or flexible printed circuit  64 . Printed circuit  66  may be formed from a rigid printed circuit board (e.g., a layer of fiberglass-filled epoxy) or a flexible printed circuit (e.g., a flexible sheet of polyimide or other flexible polymer layer). 
     Backlight structures  42  may include a light guide plate such as light guide plate  78 . Light guide plate  78  may be formed from a transparent material such as clear glass or plastic. During operation of backlight structures  42 , a light source such as light source  72  may generate light  74 . Light source  72  may be, for example, an array of light-emitting diodes. 
     Light  74  from light source  72  may be coupled into edge surface  76  of light guide plate  78  and may be distributed in dimensions X and Y throughout light guide plate  78  due to the principal of total internal reflection. Light guide plate  78  may include light-scattering features such as pits or bumps. The light-scattering features may be located on an upper surface and/or on an opposing lower surface of light guide plate  78 . 
     Light  74  that scatters upwards in direction Z from light guide plate  78  may serve as backlight  44  for display  14 . Light  74  that scatters downwards may be reflected back in the upwards direction by reflector  80 . Reflector  80  may be formed from a reflective material such as a layer of white plastic or other shiny materials. 
     To enhance backlight performance for backlight structures  42 , backlight structures  42  may include optical films  70 . Optical films  70  may include diffuser layers for helping to homogenize backlight  44  and thereby reduce hotspots, compensation films for enhancing off-axis viewing, and brightness enhancement films (also sometimes referred to as turning films) for collimating backlight  44 . Optical films  70  may overlap the other structures in backlight unit  42  such as light guide plate  78  and reflector  80 . For example, if light guide plate  78  has a rectangular footprint in the X-Y plane of  FIG. 5 , optical films  70  and reflector  80  may have a matching rectangular footprint. 
       FIG. 6  is a perspective view of an illustrative thin-film transistor layer. As shown in  FIG. 6 , thin-film transistor layer  58  may include a substrate such as substrate  84  and components on the surface of substrate  84  such as components  86 . Substrate  84  may be formed from a clear sheet of material such as a transparent glass or plastic layer (e.g., polyimide or other polymer, etc.). Components  86  may include one or more integrated circuits such as display driver integrated circuit  62 . Components  86  may also include interconnect lines and thin-film circuitry such as amorphous or polysilicon thin-film transistor circuitry. 
     An array of display pixels  94  may be formed in a central rectangular region on substrate  84 . Each display pixel  94  may include electrodes for applying an electric field to an associated portion of liquid crystal material  52 . Each display pixel  94  may also include a thin-film transistor for controlling the amount of electric field that is applied by the electrodes. Patterned traces such as lines of metal may be used in routing control signals to display pixels  94 . For example, data lines  92  may be used to route data signals to the pixels  94  from display driver integrated circuit  62  (directly or through associated thin-film transistor demultiplexer circuitry on substrate  84 ). Gate control signals may be provided to the gates of the thin-film transistors in the display pixels  94  from gate driver circuitry  96  via gate lines  90 . Gate lines  90  and data lines  92  may run perpendicular to each other to form a grid of crisscrossed metal lines on thin-film-transistor layer  58 . 
     Gate lines  90 , data lines  92 , and other conductive traces on substrate  84  may be formed from metals such as aluminum, molybdenum, chromium, copper, or other metals (as examples). Transistors in gate driver circuitry  96  and display pixels  94  and other circuitry on substrate  84  may be formed from thin-film transistor structures (e.g., amorphous silicon or polysilicon transistor structures). 
     If desired, display  14  may be configured so that thin-film transistor layer  58  is formed on top of color filter layer  56 . With this type of arrangement, which is illustrated in the cross-sectional side view of  FIG. 7 , thin-film transistor layer  58  lies nearer to exterior surface  104  of display  14  than color filter layer  56 . Color filter layer  56  may contain an array of color filter elements  56 E. Color filter elements  56 E may be formed, for example, by red, blue, and green polymer elements (e.g., polyimide containing colored dyes). As backlight unit  42  produces backlight  44 , the backlight passes through color filter elements  56 E in color filter layer  56 , thereby providing backlight  44  with color. Electrodes in the display pixels of thin-film transistor layer  58  may apply electric fields to liquid crystal material  52  so as to display images on display  14 . Viewer  48  may view the images that are displayed on display  14  when viewing display  14  in direction  50 . 
     Display driver integrated circuit  62  may be mounted on the active side (lower surface) of thin-film transistor layer  58 , as shown in  FIG. 7 . Conductive traces associated with structures  86  on substrate  84  of thin-film transistor layer  58  may be used to convey signals between display driver integrated circuit  62  and thin-film circuitry such as display pixels  94  ( FIG. 6 ). Flexible printed circuit  64  may be coupled to thin-film transistor layer  58  in inactive ledge region  82 . 
     A ring of sealant such as sealant  100  may be formed in a rectangular shape that runs around the periphery of color filter layer  56 . Sealant  100  may be formed from a polymer such as epoxy (as an example). Sealant  100  may be used to surround and laterally contain liquid crystal material  52  within display  14 . 
     Active area AA of display  14  may occupy a central rectangular portion of display  14 . A rectangular ring shaped inactive border region (border IA in  FIG. 7 ) may surround the active area. Sealant  100  and display driver integrated circuit  62  may be formed in inactive region IA. 
     Opaque masking material  102  may be used to prevent internal components such as sealant  100 , display driver integrated circuit  62 , and other components on the surface of thin-film transistor layer  58  in inactive region IA from being visible from the exterior of display  14  and device  10  (e.g., to hide these components from a viewer such as viewer  48  who is viewing display  14  in direction  50 ). Opaque masking material  102  may be formed from an organic substance (e.g., a polymer such as polyimide containing a dye or pigment such as carbon black or other substance that renders opaque masking material opaque to visible light) or may be formed from an inorganic substance such as chromium oxide that has a black or dark color. 
     Opaque masking material  102  may be formed in strips on lower (inner) surface  106  of thin-film transistor layer  58  that run along the edges of thin-film transistor layer  58 . As shown in  FIG. 8 , organic masking material  102  may be formed in a rectangular ring-shaped strip that surrounds the periphery of thin-film transistor layer  58  and that coincides with inactive area IA of  FIG. 7 . Components such as display driver integrated circuit  62  may be coupled to circuitry such as display pixels  94  using traces that run on top of opaque masking material  102  and/or that run under opaque masking material  102 . 
     The presence of reflective structures such as metal lines  90  and  92  on thin-film transistor layer  58  may give rise to a potential for undesired reflections when layer  58  is viewed in direction  50  from the exterior of display  14 . To block these metal line reflections, upper polarizer  54  may be implemented using a layer of circular polarizer material. When upper polarizer  54  is a circular polarizer, unwanted light reflections from metal structures such as traces  90  and  92  will be suppressed. To provide the exterior surface of display  14  with a smooth uninterrupted appearance, circular polarizer  54  may, if desired, extend over all or substantially all of the surface of thin-film transistor layer  58 , thereby covering all of inactive area IA and overlapping sealant  100  and integrated circuit  62  (as an example). 
     Undesired reflections from patterned metal structures on thin-film-transistor layer  58  may also be suppressed by placing some or all of the metal structures on top of a patterned layer of non-reflecting material. The non-reflecting layer may, for example, have the shape of a grid of crisscrossed lines that matches the grid of crisscrossed metal gate and data lines used in supplying control signals from display driver integrated circuit  62  and gate driver circuitry  96  to the array of display pixels  94  in the active region of display  14 . This type of configuration is shown in  FIG. 9 . 
     As shown in  FIG. 9 , thin-film transistor layer  58  may include a substrate such as substrate  84 . Substrate  84  may be a layer of clear plastic, a layer of clear glass, or other transparent material. Conductive metal traces  108  such as metal lines  90  and  92  of  FIG. 6  may be formed in a grid pattern on the underside (inner surface) of thin-film-transistor layer  58  (e.g., on the lower surface of substrate  84 ). The presence of reflections from metal traces  108  may be suppressed by interposing a matching grid of non-reflective (e.g., black) lines  110  between metal traces  108  and lower (innermost) surface  112  of substrate  84 . Lines  110  may be the same width or a slightly larger width than lines  90  and  92  (as an example). Uppermost surface  114  of thin-film-transistor substrate  84  may be covered with a layer of polarizer such as polarizer  54  (e.g., a circular polarizer or other polarizer). 
     Non-reflecting material  110  may be formed from a material that has a visible-light reflectance of less than 20%, less than 5%, less than 2%, between 3-1%, or greater than 1% (as examples). The reflectance of non-reflecting material  110  is less than the reflectance of metal traces  108  (which may be 50% or more, or 70% or more), so the presence of non-reflecting material  110  between metal traces  108  and surface  112  of substrate layer  84  suppresses reflections and helps to decrease the visibility of metal traces  108  by a viewer such as viewer  48  who is viewing display  14  in direction  50 . 
     Non-reflecting material layer  110  (which may sometimes be referred to as an antireflection layer or low-reflection layer) may be an organic material or an inorganic material. As an example, material  110  may be an organic material such as polyimide or other polymer that is rendered non-reflecting by incorporation of materials such as dyes or pigments (e.g., carbon black). Non-reflecting layer  110  may also be implemented as a single-layer structure such as a solid layer of chromium oxide or as a multilayer structure (e.g., a structure in which upper sublayer  110 ′ is formed from chromium oxide and lower sublayer  110 ″ is formed from chrome). 
     In active area AA, non-reflecting material  110  may be patterned in a layer that has a footprint matching that of lines  108 . For example, material  110  may be patterned to form lines that are comparable in width to lines  90  and that run along lines  90  in dimension X ( FIG. 6 ) and may be patterned to form lines that are comparable in width to lines  92  that run along lines  92  in dimension Y ( FIG. 6 ). 
     Material  110  in inactive region IA may serve to block components such as display driver circuit  62  from view in direction  50 , as described in connection with opaque masking layer  102  of  FIG. 7  (i.e., opaque masking layer  102  may be formed from a non-reflecting material such as material  110  of  FIG. 9 ). 
     Metal  108  in region IA may be patterned to form traces that distribute signals from display driver integrated circuit  62  to display components such as an array of display pixels  94  in active area AA. Traces for distributing signals between contacts that are associated with the attachment of flexible printed circuit  64  to thin-film-transistor layer  58  and display driver integrated circuits such as integrated circuit  62  may also be formed on the lower (innermost) surface of layer  110 . 
     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: 20120927
Publication Date: 20180724
Grant Date: 20180724
Priority Date: 20120927
Inventors: YIN, VICTOR H.
QI, JUN
MATHEW, DINESH C.
CHANG, SHIH-CHANG
CHEN, CHENG
ZHONG, JOHN Z.
CHEN, WEI
GARELLI, ADAM T.
POSNER, BRYAN W.
LIGTENBERG, CHRISTIAAN A.
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F1/13454", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133528", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/1362", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/1362", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13454", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/1362", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13454", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133514", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133528", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/136209", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/136209", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/136209", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133528", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F2001/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/1362", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F2001/133562", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/13454", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/136209", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F2001/133541", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133528", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/133562", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133388", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133541", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133541", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133562", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133541", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133562", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 50338498