PATENT DOCUMENT

Publication Number: US-9075199-B2
Application Number: US-201213664413-A
Country: US
Kind Code: B2

Title: Displays with polarizer layers for electronic devices

Abstract:
An electronic device may have a display. Inactive portions of the display may be masked using an opaque masking layer. An opening may be provided in the masking layer. A camera may receive light through the opening in the opaque masking layer. The display may include upper and lower polarizers, a color filter layer, and a thin-film transistor layer. The upper polarizer may have an unpolarized window aligned with the opening in the opaque masking layer for the camera, a logo, or another internal structure. The unpolarized window may be formed from openings in polarizer layers such as a polyvinyl alcohol layer and optical retarder layers. The openings may pass through all or less than all of the polarizer layers. The openings may be filled with transparent filler material. The polarizer may include a try-acetyl cellulose layer that continuously covers the opening in other polarizer layers.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a display having an active region and an inactive region; 
 a polarizer in the display, wherein the polarizer overlaps the active region and the inactive region and wherein the polarizer comprises a plurality of polarizer layers; and 
 an unpolarized window in the polarizer within the inactive region, wherein the unpolarized window is formed from an opening in less than all of the plurality of polarizer layers and transparent material in the opening and wherein at least one of the polarizer layers completely covers the opening. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the plurality of polarizer layers comprises a polyvinyl alcohol layer and a tri-acetyl cellulose layer and wherein the opening comprises an opening in the polyvinyl alcohol layer. 
     
     
       3. The electronic device defined in  claim 2  wherein the tri-acetyl cellulose layer comprises a continuous tri-acetyl cellulose layer having a portion that passes over the opening in the polyvinyl alcohol layer. 
     
     
       4. The electronic device defined in  claim 3  wherein the opening extends partially into the tri-acetyl cellulose layer. 
     
     
       5. The electronic device defined in  claim 3  wherein the plurality of polarizer layers further comprises an optical retarder layer attached to the polyvinyl alcohol layer. 
     
     
       6. The electronic device defined in  claim 5  wherein the opening extends through the optical retarder layer. 
     
     
       7. The electronic device defined in  claim 6  wherein the plurality of polarizer layers further comprises at least one optically clear adhesive layer on the optical retarder layer and wherein a portion of the at least one optically clear adhesive layer fills the opening in the polyvinyl alcohol layer and the optical retarder layer. 
     
     
       8. The electronic device defined in  claim 6  wherein the plurality of polarizer layers further comprises an additional optical retarder layer and an optically clear adhesive layer interposed between the optical retarder layer and the additional optical retarder layer and wherein the opening extends through the additional optical retarder layer and the optically clear adhesive layer. 
     
     
       9. The electronic device defined in  claim 8  wherein the plurality of polarizer layers further comprises an additional optically clear adhesive layer on the additional optical retarder layer and wherein a portion of the additional optically clear adhesive layer fills the opening in the polyvinyl alcohol layer, the optical retarder layer, the optically clear adhesive layer, and the additional optical retarder layer. 
     
     
       10. The electronic device defined in  claim 9  wherein the display further comprises a color filter layer and wherein the additional optically clear adhesive layer attaches the polarizer to the color filter layer. 
     
     
       11. The electronic device defined in  claim 10 , further comprising a camera that is aligned with the unpolarized window. 
     
     
       12. A display, comprising:
 a color filter layer; and 
 a polarizer attached to the color filter layer, wherein the polarizer comprises an unpolarized window, wherein the polarizer forms an outermost surface of the display, and wherein outermost surface is a smooth surface that continuously passes over the unpolarized window in the polarizer. 
 
     
     
       13. The display defined in  claim 12  wherein the polarizer comprises a tri-acetyl cellulose layer, a polyvinyl alcohol layer, a plurality of optical retarder layers, and a plurality of optically clear adhesive layers. 
     
     
       14. The display defined in  claim 13  wherein the unpolarized window in the display comprises an opening in the tri-acetyl cellulose layer, the polyvinyl alcohol layer, the plurality of optical retarder layers, and the plurality of optically clear adhesive layers. 
     
     
       15. The display defined in  claim 14  wherein the polarizer further comprises a protective layer formed over the tri-acetyl cellulose layer and wherein the protective layer includes a portion that fills the opening. 
     
     
       16. The display defined in  claim 15  wherein a selected one of the plurality of optically clear adhesive layers attaches the polarizer to the color filter layer.

Description:
BACKGROUND 
     This invention relates to electronic devices and, more particularly, to display structures for electronic devices such as portable computers. 
     Electronic devices such as portable computers and cellular telephones typically have displays. To provide protection from damage, many displays are provided with cover glass layers. The cover glass layer helps protect underlying display structures from scratches and other damage during use of the electronic device. A patterned layer of black ink is sometimes formed on the underside of the cover glass layer to form an opaque border region. The opaque border region can hide internal device components from view. An opening in the black ink can be provided for a camera that is mounted behind the cover glass. 
     As device manufacturers strive to reduce device size and weight, it is becoming unacceptable to include potentially bulky and heavy display structures in a display. It may therefore be desirable to omit the cover glass layer from a display. Care must be taken, however, to ensure that unsightly internal components remain hidden from view and that internal components such as cameras are still able to function properly. 
     It would therefore be desirable to be able to provide improved display structures in electronic devices such as portable computers and cellular telephones. 
     SUMMARY 
     An electronic device such as a portable computer, cellular telephone, or other electronic equipment may have a display. The display may have an active portion such as a central rectangular region in which images are presented to a user of the device. Inactive portions of the display such as peripheral portions of the display may be masked using an opaque masking layer. The opaque masking layer may be formed from colored ink. 
     An opening may be provided in the opaque masking layer to allow light to pass. For example, a logo or other information may be viewed through an opening in the opaque masking layer. Cameras and other internal electronic components may receive light through an opening in the opaque masking layer. 
     The display may include upper and lower polarizers, a color filter layer, and a thin-film transistor layer. The opaque masking layer may be formed on the upper polarizer, may be interposed between the upper polarizer and the color filter layer, or may be interposed between the color filter layer and the thin-film transistor layer. 
     The upper polarizer may have unpolarized windows. The upper polarizer may be formed from polarizer layers such as a layer of stretched polyvinyl alcohol, a layer of tri-acetyl cellulose, one or more optical retarder layers and one or more layers of adhesive such as optically clear adhesive. An unpolarized window in the upper polarizer may be formed from a region of the upper polarizer in which the polyvinyl alcohol layer has been removed. In this way, light that passes through an opening in the polyvinyl alcohol layer in the unpolarized window portion of the upper polarizer may pass through the upper polarizer without being attenuated by the polarizing effects of the upper polarizer. Polarizer layers may be removed by drilling using, for example, laser drilling equipment. 
     The unpolarized window may include optically transparent material such as an optically clear adhesive, a transparent polymer or glass that fills the region in which the polyvinyl alcohol layer has been removed. The upper polarizer may include openings in other polarizer layers. The optically transparent material may be formed in the openings in the other polarizer layers. In some configurations, the tri-acetyl cellulose layer may extend across the unpolarized window over the opening in the polyvinyl alcohol layer. In other configurations, the transparent material may fill an opening in the tri-acetyl cellulose layer and may cover the tri-acetyl cellulose layer. 
     A camera may be aligned with the unpolarized window in the polarizer and the opening in the opaque masking layer to receive image light. A logo may be aligned with the unpolarized window in the polarizer layer and the opening in the opaque masking layer so that the logo is visible from the exterior of the device. Other internal components of the electronic device such as sensors and status indicators may also be mounted beneath unpolarized windows in the polarizer and openings in the opaque masking layer. 
     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 portable computer with display structures in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view of a handheld electronic device with display structures in accordance with an embodiment of the present invention. 
         FIG. 3  is a cross-sectional side view of an electronic device having a display in accordance with an embodiment of the present invention. 
         FIG. 4  is a cross-sectional side view of illustrative display structures in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an illustrative polarizer having polarizer layers that include multiple tri-acetyl cellulose layers for an electronic device display in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of an illustrative polarizer having polarizer layers that include a tri-acetyl cellulose layer and multiple optical retarder layers for an electronic device display in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of an illustrative display having an upper polarizer with an unpolarized window that exposes internal device structures in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of a portion of a display having an upper polarizer with an unpolarized window formed from an opening in a polyvinyl alcohol layer and an optical retarder layer in accordance with an embodiment of the present invention. 
         FIG. 9  is a diagram of an illustrative system for forming an upper polarizer with an unpolarized window formed from an opening in a polyvinyl alcohol layer and an optical retarder layer in accordance with an embodiment of the present invention. 
         FIG. 10  is a diagram showing how openings may be formed in polarizer layers during lamination operations for the polarizer in accordance with an embodiment of the present invention. 
         FIG. 11  is a flow chart of illustrative steps that may be used in forming openings in polarizer layers during lamination operations for the polarizer in accordance with an embodiment of the present invention. 
         FIG. 12  is a cross-sectional side view of a portion of a display having an upper polarizer with an unpolarized window formed from an opening in a polyvinyl alcohol layer and multiple optical retarder layers in accordance with an embodiment of the present invention. 
         FIG. 13  is a diagram showing how openings may be formed in polarizer layers following lamination operations for the polarizer in accordance with an embodiment of the present invention. 
         FIG. 14  is a flow chart of illustrative steps that may be used in forming openings in polarizer layers following lamination operations for the polarizer in accordance with an embodiment of the present invention. 
         FIG. 15  is a cross-sectional side view of a portion of a display having an upper polarizer with an unpolarized window formed from a through-hole in the upper polarizer that is filled with a transparent material in accordance with an embodiment of the present invention. 
         FIG. 16  is a diagram showing how through-holes may be formed in a polarizer and how the through-holes may be filled with transparent materials following lamination operations for the polarizer in accordance with an embodiment of the present invention. 
         FIG. 17  is a flow chart of illustrative steps that may be used in forming a polarizer with an unpolarized window formed from a through-hole in the upper polarizer that is filled with a transparent material in accordance with an embodiment of the present invention. 
         FIG. 18  is a diagram of a laser drilling system with an optical feedback loop showing how the system may be used in drilling openings in polarizer layers of a polarizer for an unpolarized window in the polarizer in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as notebook computers, tablet computers, cellular telephones, and other computing equipment may be provided with displays. 
     An illustrative electronic device such as a portable computer or other electronic equipment that has a display is shown in  FIG. 1 . As shown in  FIG. 1 , display  14  of device  10  may be mounted in upper housing portion  12 A of housing  12 . Housing  12  may be formed from a unibody construction in which some or all of housing  12  is formed form a unitary piece of material (e.g., metal, plastic, or fiber composite materials) or may be formed from multiple structures that have been mounted together using adhesive, fasteners, and other attachment mechanisms. For example, housing  12  may be formed from frame members and other internal supports to which external plates, housing sidewalls, bezel structures, and other structures are mounted. 
     Because housing portion  12 A may be used to house display  14 , housing portion  12 A may sometimes be referred to as a display housing. Display housing  12 A may be attached to housing portion  12 B (sometimes referred to as a main unit or base housing) using hinge structures  18 , so that display housing  12 A may rotate relative to main housing  12 B around hinge axis  16 . Device  10  may include ports for removable media, data ports, keys such as keyboard  20 , input devices such as track pad  24 , microphones, speakers, sensors, status indicators lights, etc. 
     Display  14  may have an active portion and an inactive portion. Active portion  28 A of display  14  may have a shape such as the rectangular shape that is bounded by dashed line  28 D in  FIG. 1 . Inactive portion  281  of display  14  may have a rectangular ring shape or other suitable shape and may form a border around the periphery of display  14 . Image pixel array elements such as liquid crystal diode image pixels or other active image pixel structures may be used in portion  28 A to present images to a user of device  10 . Inactive portion  281  is generally devoid of image pixel elements and does not participate in forming images for a user. To hide unsightly internal components from view, internal components in inactive portion  281  may be blocked from view using an opaque masking layer such as a layer of ink. 
     Device  10  may have components that are formed in inactive device region  281 . For example, device  10  may have a camera such as camera  22 . Camera  22  may be mounted within display housing  12 A and may operate through a window (sometimes referred to as a camera window) in display  14 . 
     Information structures  26  such as a logo may be mounted on device  10 . Information structures  26  may be a trademarked logo that represents a manufacturer of device  10 , may be printed text, may be trademarked text, may be a design, may be personalized information (e.g., information identifying an owner of device  10 ), may be formed from a combination of text and non-text information, or may include other suitable content. Information structures  26  may be formed from patterned ink, patterned paint, patterned polymer, patterned metal traces, or other suitable materials. 
     Information structures  26  may be mounted in upper housing  12 A. For example, information structures  26  or may be formed in inactive display region  281  of upper housing  12 A under a transparent window in display  14 . 
       FIG. 2  is a perspective view of an illustrative configuration that may be used for a handheld electronic device. Electronic device  10  of  FIG. 2  may be, for example, a cellular telephone or other handheld electronic equipment. Device  10  of  FIG. 1  may have housing  12 . Display  14  may be mounted within housing  12  on the front of device  10 . Active portion  28 A of display  14  may lie within rectangular boundary  28 D. Inactive portion  281  of display  14  may form a boundary around the periphery of display  14 . Housing  12  may have sidewalls that run around the periphery of device  10  (as an example). The sidewall structures of housing  12  may be formed from metal, plastic, glass, ceramic, carbon-fiber materials or other fiber-based composites, other materials, or combinations of these materials. The rear of housing  12  may be formed from metal, plastic, a planar member such as a glass or ceramic plate, fiber-based composites, other materials, or combinations of these materials. 
     Device  10  may have openings such as openings  34  in the sidewalls of housing  12 . Openings  34  may be used to form microphone and speaker ports, openings to accommodate button members, openings for data ports and audio jacks, etc. One or more openings may be formed in inactive region  281  of display  14 . For example, one or more openings may be formed in inactive region  281  for buttons such as button  32  (e.g., a menu button). Openings such as opening  30  may also be formed in inactive region  281  (e.g., to form a speaker port for an ear speaker). 
     Camera  22  may be formed behind a window in device  10  such as a camera window in inactive region  281  (as an example). If desired, windows may also be formed over information such as logo information (see, e.g., information structures  26  of  FIG. 1 ) to allow the logo or other information to be viewed by a user of device  10 . Windows for camera  22  and/or logo  26  may be formed from openings in an opaque masking layer that are aligned with unpolarized windows in a display polarizer. Display  14  may have a smooth outer surface that passes continuously over the windows for camera  22  and/or logo  26 . 
     The illustrative electronic device structures of  FIGS. 1 and 2  are merely examples. Any suitable electronic devices  10  may be provided with displays  14 . Electronic devices  10  may, for example, include tablet computers, wristwatch devices, pendant devices, other miniature and wearable devices, televisions, computer displays, accessories, etc. 
     A cross-sectional end view of an electronic device with a display (e.g., a device such as device  10  of  FIG. 2 , a portion of device  10  of  FIG. 1 , etc.) is shown in  FIG. 3 . As shown in  FIG. 3 , display  14  may be mounted within housing  12  so that exterior surface  90  of display  14  is exposed. Device housing  12  may be used to enclose printed circuit boards such as printed circuit board  36 . Printed circuit board  36  may be a rigid printed circuit board such as a fiberglass-filled epoxy printed circuit board (e.g., FR4), a flexible printed circuit (“flex circuit”) formed from a flexible dielectric such as a sheet of polyimide with patterned conductive traces, a rigid flex substrate, or other substrate. 
     Electrical components such as components  37  may be mounted to boards such as board  36 . Electrical components  37  may include switches, resistors, inductors, capacitors, integrated circuits, connectors, cameras, sensors, speakers, or other device components. These components may be soldered or otherwise connected to board  36 . 
     Display  14  may be a touch screen display. Touch screen displays such as display  14  of  FIG. 3  may include an array of capacitive electrodes (e.g., transparent electrodes such as indium tin oxide electrodes), or may include a touch sensor array based on other touch technologies (e.g., resistive touch sensor structures, acoustic touch sensor structures, piezoelectric sensors and other force sensor structures, etc.) The touch structures for display  14  may be implemented on a dedicated touch sensor substrate such as a layer of glass or may be formed on the same layer of glass that is being used for other display functions. For example, touch sensor electrodes may be formed on a color filter array layer, a thin-film transistor layer, or other layers in a liquid crystal display (LCD). 
     Display  14  may, in general, be formed from any suitable type of display structures. Examples of display structures that may be used for display  14  include liquid crystal display (LCD) structures, organic light-emitting diode (OLED) structures, plasma cells, and electronic ink display structures. Arrangements in which display  14  is formed from liquid crystal display (LCD) structures are sometimes described herein as an example. This is merely illustrative. In general, display  14  may be formed using any suitable display technology. 
     A cross-sectional view of display  14  of  FIGS. 1 ,  2  and  3  is shown in  FIG. 4 . As shown in  FIG. 4 , display  14  may include a backlight unit (BLU) such as backlight unit  38 . Light  44  for backlight unit  38  may be launched into light-guide panel  51  from light source  42 . Light source  42  may be formed from an array of light-emitting diodes (as an example). Reflector  49  (e.g., white polyester) may be used to reflect light  44  upwards (outwards) in direction  46  through display module  40 . Optical films  48  may include a diffuser layer and light collimating layers (as an example). 
     Display  14  and display module  40  may have an active region  28 A that produces image pixel light  43  from an array of image pixels. Image pixel light  43  forms an image in active region  28 A that may be viewed by a user of device  10 . The image may include text, graphics, or other image information. A portion of display  14  and display module  40  such as region  281  may be inactive. Region  281  may have a shape that surrounds the periphery of display  14  and display module  40  as shown in  FIG. 1  (as an example). Inactive region  281  generally does not contain active image pixels and may include an opaque masking layer to block interior structures from view. Backlight unit  38  may have a footprint that is aligned with active region  28 A or may have edges that extend under some or all of inactive region  281  (as shown in  FIG. 4 ). 
     Display module  40  may include a lower polarizer such as lower polarizer  50  and an upper polarizer such as polarizer  62 . A thin layer (e.g., 3-5 microns) of liquid crystal material  58  may be interposed between color filter layer  60  and thin-film transistor layer  52 . 
     Thin-film transistor layer  52  may be formed on a transparent planar substrate such as a layer of glass or plastic. The upper surface of thin-film-transistor layer  52  may contain pixel electrode structures and thin-film transistors (shown as circuitry  54  above dashed line  56 ). The circuitry on thin-film-transistor layer  52  may be organized into an array of image pixels that can be controlled to display images on display  14  for a user of device  10 . 
     Color filter layer  60  may include colored filter pixel elements (e.g., red, green, and blue filter elements) that provide display  14  with the ability to display color images. Color filter layer  60  may be formed using a transparent planar substrate such as a glass or plastic substrate. 
     If desired, other layers of material may be included within display module  40  and backlight unit  38 . For example, display module  40  and backlight unit  38  may include one or more layers of material for forming a touch sensor, layers of optical films such as birefringent compensating films, antireflection coatings, scratch prevention coatings, oleophobic coatings, layers of adhesive, etc. 
     Polarizers such as upper (outer) polarizer  62  and lower (inner) polarizer  50  may be formed from multiple layers of material that are laminated together. An illustrative laminated polarizer is shown in the cross-sectional side view of  FIG. 5 . As shown in  FIG. 5 , polarizer  62  (i.e., an upper polarizer in this example) may have polarizer film  68 . Film  68  may be formed from a stretched polymer such as stretched polyvinyl alcohol (PVA) and may therefore sometimes be referred to as a PVA layer. Iodine may be placed on to the stretched PVA film so that iodine molecules align with the stretched film and form the polarizing layer of polarizer  62 . Other polarizer films may be used if desired. Polarizer film  68  may be sandwiched between layers  66  and  70 . Layers  66  and  70  may be formed from a material such as tri-acetyl cellulose (TAC) and may sometimes be referred to as TAC films or TAC layers. The TAC films may help hold the PVA film in its stretched configuration and may protect the PVA film. Other films such as optical retarder films may be laminated to film  68  if desired. 
     Coating layer  72  may be formed from one or more films of material that provide polarizer  62  with desired surface properties. For example, layer  72  may be formed from optical enhancement materials that provide polarizer  62  with antiglare (light diffusing) properties or antireflection properties or protective properties such as scratch resistance, fingerprint resistance, and other desired properties. 
     Layer  72  may be formed from one or more layers of material such as antireflection (AR) layers (e.g., films formed from a stack of alternating high-index-of-refraction and low-index-of-refraction layers), antiglare (AG) layers, antireflection-antiglare (AR/AG) layers, oleophobic layers, antiscratch coatings, or other coating layers. The functions of these layers need not be mutually exclusive. For example, an antiglare film in coating  72  may help provide polarizer  62  with scratch resistance. 
     Polarizer  62  may, if desired, be provided with a layer of adhesive such as adhesive  64  (e.g., optically clear adhesive) to help attach polarizer  62  to the upper surface of display module  40  (i.e., color filter  60  of  FIG. 4 ). However, the example of  FIG. 5  in which polarizer  62  includes multiple layers of tri-acetyl cellulose and a single layer of adhesive  64  is merely illustrative. If desired, polarizer  62  may include a single layer of tri-acetyl cellulose attached to the polyvinyl alcohol layer and one or more optical retarder (OR) layers as shown in  FIG. 6 . 
     In the example of  FIG. 6 , a layer of optically retarding material such as an optical retarder film  82  is laminated to a surface of the polyvinyl alcohol layer and tri-acetyl cellulose layer  80  is laminated to an opposing surface of the polyvinyl acetate layer. Polarizer  62  may also include a layer of optically clear adhesive  64  (e.g., an optically clear pressure sensitive adhesive or other optically clear adhesive) on the optical retarder layer  82  that is attached to polyvinyl alcohol layer  68 . The optically clear adhesive  64  on the optical retarder layer  82  that is attached to polyvinyl alcohol layer  68  may attach another layer  82  of optically retarding material to polarizer  62 . Polarizer  62  may be provided with an additional layer of optically clear adhesive  64  that helps attach polarizer  62  to the upper surface of display module (i.e., color filter  60  of  FIG. 4 ). The thickness of polarizer  62  may be about 50-200 microns (as an example). 
     It is often desirable to mount electronic components such as cameras and other structures within the interior of an electronic device that interact with light that is transmitted into or out of the device. If desired, a camera or other internal device structure that interacts with light that is transmitted into or out of the device may be mounted under a portion of the display module. As shown in  FIG. 7 , for example, internal structure  102  may be mounted below an edge portion of color filter layer  60  and polarizer  62  (as an example). Internal structure  102  may be a camera (e.g., a camera such as camera  22  of  FIGS. 1 and 2  that receives light  86  through layer  60  and polarizer  62 ), a sensor that receives light through layer  60  and polarizer  62 , patterned information structures in the shape of a logo or other information such as structures  26  of  FIG. 1 , a status indicator (e.g. a status indicator element that emits light through layer  60  and polarizer  62 ), or other suitable internal structures in device  10 . 
     Polarizer  62  may include an unpolarized window  84 . Portions of polarizer  62  other than unpolarized window  84  may attenuate the amount of unpolarized light  86  that enters device  10  or the amount of unpolarized light  88  that exits device  10  by blocking a portion of the unpolarized light. Unpolarized window  84  may be portion of polarizer  62  that allows light of substantially all polarizations to pass through window  84 . 
     Unpolarized window  84  may be a portion of polarizer  62  that includes an opening in a polyvinyl alcohol layer of the polarizer. Unpolarized window  84  may have a thickness that is substantially the same as the thickness of other portions of polarizer  62 . Outer surface  90  of polarizer  62  may form an outer surface of device  10 . Outer surface  90  may be a smooth outer surface without any surface features (e.g., openings or protrusions) in the vicinity of unpolarized window  84 . Unpolarized window  84  may have an outer surface portion that is formed in a plane with other portions of outer surface  90 . Unpolarized window  84  may include a continuous layer of tri-acetyl cellulose over the opening in the polyvinyl alcohol layer so that the outer surface of polarizer  62  is a continuous outer surface without any openings. However, this is merely illustrative. If desired, unpolarized window  84  may include an opening in both the polyvinyl alcohol layer and the tri-acetyl cellulose layer and a protective transparent material that covers that tri-acetyl cellulose layer and fills the opening in the polyvinyl alcohol layer and the TAC layer. 
     Unpolarized window  84  may be formed from openings that have circular shapes (e.g., for forming a circular opening that is aligned with a camera lens), rectangular shapes (e.g., for exposing a logo or other information that has a rectangular outline), or other suitable shapes. 
     To ensure that potentially unsightly internal portions of device  10  are blocked from view, device  10  may be provided with one more layers of opaque masking material  92 . For example, opaque masking layer  92  may be incorporated onto one or more of the layers of material in display module  40  of  FIG. 4 . The opaque masking layer may be formed from black ink, ink with other (non-black) colors (e.g., white, silver, gray, red, blue), an opaque polymer, a layer of metal, or other suitable opaque substances. 
     Examples of locations in which the opaque masking layer may be formed in module  40  (see  FIG. 4 ) include position P 1  on the top of polarizer  62 , position P 2  on the lower surface of polarizer  62 , position P 3  on the top surface of color filter layer  60 , and position P 4  on the lower surface of color filter layer  60 . Other masking layer locations and combinations of masking layer locations may be used if desired. Opaque masking layer  92  may include an opening such as opening  94  that is aligned with unpolarized window  84  of polarizer  62  so that incoming light  86  and/or outgoing light  88  can pass through unpolarized window  84  and opening  94  to and/or from structure  102 . 
       FIG. 8  is a cross-sectional side view of a portion of a polarizer such as polarizer  62  having a continuous outer surface  90  and an unpolarized window  84  that allows light  86  to reach structure  102  through window  84 . In the example of  FIG. 8 , unpolarized window  84  is formed from an opening  100  in PVA layer  68  and adjacent optical retarder layer  82 . As shown in  FIG. 8 , opening  100  may, if desired, extend partially into TAC layer  80 . However, whether or not opening  100  extends partially into TAC layer  80 , TAC layer  80  may include at least a portion that passes continuously over opening  100  in PVA layer  68  so that outer surface  90  of polarizer  62  is a continuous outer surface. 
     Coating materials  72  may be formed over the continuous surface of tri-acetyl cellulose layer  80 . Opening  100  in PVA layer  68  and optical retarder layer  82  may be filled with a transparent material such as a portion of optically clear adhesive layer  64 . Because PVA layer  68  is the layer of polarizer  62  that polarizes light, opening  100  in PVA layer  68  prevents light  86  that passes through window  84  from being affected by the polarizing effects of polarizer  62 . 
     Opening  100  may be formed in PVA layer  68  and optical retarder layer  82  using a system of the type shown in  FIG. 9 . The system of  FIG. 9  may use roll-to-roll and sheet-to-sheet lamination processes to form polarizer  62 . As shown in  FIG. 9 , a carrier substrate may be provided in the form of a roll of material such as carrier layer roll  104 . PVA layer  68  and tri-acetyl cellulose layer  80  may be provided in a roll of PVA sheet material that is laminated to tri-acetyl cellulose sheet material such PVA/TAC roll  106 . Optical retarder layer  82  may be dispensed from a roll of optical retarder sheet material such as roll  108 . 
     In a continuous process, rolls  104 ,  106 , and  108  may dispense a carrier layer, a laminated TAC/PCA layer, and an optical retarder layer. The layers may be compressed (laminated) together using lamination equipment  110  such as rollers  120  or other roll-to-roll lamination equipment to form a sheet of materials such as sheet  124 . The roll-to-roll lamination process may then continue by passing sheet  124  under drilling equipment  112 . 
     Drilling equipment  112  may then be used to drill openings  100  in sheet  124  (e.g., openings in the PVA layer and the optical retarder layer that do not pass through the TAC layer). Drilling equipment  112  may include a laser such as laser  134  that emits a laser beam such as an infrared laser beam, an ultraviolet laser beam, or an optical laser beam. Laser  134  may be a continuous wave laser or a pulsed laser. The position of laser  134  may be controlled using computer-controlled positioner  136 . Drilling equipment  112  may include additional optical components such as aperture  130  and lens  132  that help focus the laser beam from laser  134  for laser drilling of sheet  124 . 
     After forming openings  100  in sheet  124 , remaining polarizer layers of polarizer  62  may be laminated to sheet  124  using additional laminating equipment  110  such as rollers  122 . For example, a sheet of optically clear adhesive may be dispensed from roll  140  and laminated to the optical retarder sheet from roll  108 . The adhesive sheet may include portions that fill openings  100  in sheet  124 . However, this is merely illustrative. If desired, optically clear adhesive material may be deposited onto the optical retarder sheet and into openings  100  from a dispenser. An additional layer of optical retarder material may be then be dispensed from roll  140  and laminated onto the optical retarder sheet that came from roll  108  using the deposited adhesive. If desired, additional materials may be laminated to sheet  124  to form polarizer  62 . Laminating equipment  110  may include other equipment such as ovens, dispensers, computing equipment or other equipment. Drilling equipment  112  may include other equipment such as mechanical drills, monitoring equipment, computing equipment or other equipment. 
     If desired, the roll-to-roll lamination operations may be performed in one or more individual steps, rather than continuously as shown in  FIG. 9 . For example, following a first roll-to-roll lamination operation to produce material  124 , material  124  may be collected onto a roll at one manufacturing facility. Later, at the same facility or at another manufacturing facility, that roll of material  124  may be cut, drilled and laminated with additional polarizer layers (e.g., optical retarder layers or other optical films) to form polarizer  62  in a subsequent lamination operation. 
       FIG. 10  is a diagram showing how opening  100  may be formed in PVA layer  68  and optical retarder layer  82  during lamination operations. As shown in  FIG. 10 , lamination tools  110  may be used to form a laminated sheet such as sheet  124  having a carrier layer  142 , TAC layer  80 , PVA layer  68 , and optical retarder  82 . Drilling tool  112  may be used to form an opening such as opening  100  in sheet  124 . Opening  100  may be an opening in PVA layer  68 , optical retarder layer  82  and, if desired, a portion of TAC layer  80 . 
     Lamination and coating tools  114  (e.g., laminating tools  110  and additional tools for providing coatings such as anti-reflective coatings, anti-glare coatings, oleophobic coatings, etc.) may be used to provide transparent material such as optically clear adhesive material in opening  100 , to form additional polarizer layers such additional optically clear adhesive layers  64  and additional optical retarder layers  82  on sheet  124 , and to form coating  72  on tri-acetyl cellulose layer  80 . Lamination and coating tools  114  may also be used to remove carrier layer  142  from tri-acetyl cellulose layer  80  prior to providing coating  72  on TAC layer  80 . 
     Illustrative steps involved in forming a polarizer such as polarizer  62  having an unpolarized window such as window  84  formed from an opening in a PVA layer and an optical retarder layer are shown in  FIG. 11 . 
     At step  150 , an optical retarder layer, a polyvinyl alcohol layer, and a tri-acetyl cellulose (triacetate cellulose) layer may be attached (e.g., laminated) to a carrier layer. 
     At step  152 , an opening may be drilled in the optical retarder layer and the polyvinyl alcohol layer. If desired, the opening may extend partially into the tri-acetyl cellulose layer. 
     At step  154 , transparent material such as optically clear adhesive material may be provided in the drilled opening and over the optical retarder layer. 
     At step  156 , one or more additional optical retarder layers and one or more additional adhesive layers may be laminated onto the provided optically clear adhesive. 
     At step  158 , optical enhancement materials such as an antireflection coating or other coating materials may be formed on the tri-acetyl cellulose layer. 
     At step  160 , the polarizer layer with the drilled opening that is filled with the transparent material may be attached to additional display structures such as a display color filter glass layer. 
     The example described in  FIGS. 8-11  in which unpolarized window  84  is formed from an opening in PVA layer  68  and optical retarder layer  82  without passing through other polarizer layers is merely illustrative. Polarizer  62  may be formed with a continuous outer surface and an unpolarized window using other configurations such as those described below in connection with  FIGS. 12-17 . 
     As shown in  FIG. 12 , polarizer  62  may have a continuous outer surface  90  and an unpolarized window  84  formed from an opening  101  in PVA layer  68 , multiple optical retarder layers  82  and multiple adhesive layers  64 . Opening  101  may also, if desired, extend partially into tri-acetyl cellulose layer  80 . However, TAC layer  80  may pass continuously over opening  101  in PVA layer  68 , retarder layers  82  and adhesive layers  64  so that outer surface  90  of polarizer  62  is a continuous outer surface. Coating materials  72  may be formed over the continuous surface of tri-acetyl cellulose layer  80 . Opening  101  in PVA layer  68 , retarder layers  82  and adhesive layers  64  may be filled with a transparent material such as a portion of optically an outermost optically clear adhesive layer  64 . 
     The optically clear adhesive layer  64  that extends into opening  101  and fills opening  101  may be used to attach polarizer layer  62  to color filter layer  60 . 
       FIG. 13  is a diagram showing how opening  101  may be formed in PVA layer  68 , retarder layers  82  and adhesive layers  64  following lamination operations for polarizer  62 . As shown in  FIG. 13 , lamination tools  110  may be used to form polarizer  62 ′ without any unpolarized windows and to attach polarizer  62 ′ to carrier layer  142 . Drilling tools  112  may then be used to form an opening such as opening  101  in polarizer  62 ′ that passes through PVA layer  68 , retarder layers  82 , adhesive layers  64 , and, if desired, a portion of TAC layer  80 . 
     Filling, carrier removal, and coating tools  115  (e.g., adhesive dispenser, coating dispensers, and additional tools) may be used to provide additional transparent material such as additional optically clear adhesive material in opening  101 , to remove carrier  142  from TAC layer  80 , and to form coating  72  on TAC layer  80 . 
     Illustrative steps involved in forming a polarizer such as polarizer  62  having an unpolarized window such as window  84  formed from an opening in a PVA layer, multiple optical retarder layers and multiple adhesive layers are shown in  FIG. 14 . 
     At step  170 , a display polarizer may be provided that includes adhesive layers, optical retarder layers, a polyvinyl alcohol layer, and a tri-acetyl cellulose layer. 
     At step  172  the display polarizer may be attached to a temporary carrier layer. 
     At step  174 , an opening may be drilled in the display polarizer that passes through the adhesive layers, the optical retarder layers and the polyvinyl alcohol layer. If desired, the opening may extend partially into the tri-acetyl cellulose layer. The opening may be drilled using laser drilling equipment (as an example). 
     At step  176 , transparent filler material such as optically clear adhesive material may be provided in the drilled opening. 
     At step  178 , the temporary carrier layer may be removed. 
     At step  180 , optical enhancement materials such as an antireflection coating or other coating materials may be formed on the tri-acetyl cellulose layer. 
     At step  182 , the polarizer layer with the drilled opening that is filled with the transparent material may be attached to additional display structures such as a display color filter glass layer. 
     As shown in  FIG. 15 , polarizer  62  may have a continuous outer surface  90  that is formed from a protective layer such as protective layer (PL)  188  (and associated films  72 ) and an unpolarized window  84  formed from an opening  103  in PVA layer  68 , multiple optical retarder layers  82 , multiple adhesive layers  64 , and TAC layer  80 . 
     Protective layer  188  may be formed from transparent materials such as transparent polymers or glass. Protective layer  188  may include a portion that covers TAC layer  80  and a portion that fills opening  103 . In this way, unpolarized window  84  may be formed from an opening (e.g., a through-hole) that passes through substantially all of the polarizer layers of polarizer  62  while maintaining a smooth, continuous outer surface for polarizer  62 . 
     Materials  72  may be formed over the continuous surface protective layer  188 . 
       FIG. 16  is a diagram showing how through-hole  103  may be formed in PVA layer  68 , retarder layers  82 , adhesive layers  64 , and tri-acetyl cellulose layer  80  following lamination operations for polarizer  62 . As shown in  FIG. 16 , lamination tools  110  may be used to form polarizer  62 ′ without any unpolarized windows. Drilling tools  112  may then be used to form an opening such as through-hole  103  in polarizer  62 ′ that passes through PVA layer  68 , retarder layers  82 , adhesive layers  64 , and tri-acetyl cellulose layer  80 . 
     Filling and coating tools  117  (e.g., adhesive dispenser, coating dispensers, polymer dispensers, liquid glass dispensers, and/or additional tools) may be used to provide additional transparent material such as polymer or glass material for protective layer  188  in opening  103  and over TAC layer  80 . 
     Illustrative steps involved in forming a polarizer such as polarizer  62  having an unpolarized window such as window  84  formed from a through-hole in a PVA layer, multiple optical retarder layers, multiple adhesive layers, and a TAC layer are shown in  FIG. 17 . 
     At step  190 , a display polarizer may be provided that includes adhesive layers, optical retarder layers, a polyvinyl alcohol layer, and a tri-acetyl cellulose (triacetate cellulose) layer. 
     At step  192 , an opening such as a through-hole may be drilled in the display polarizer that passes through the display polarizer (e.g., through the adhesive layers, the optical retarder layers, the polyvinyl alcohol layer, and the tri-acetyl cellulose layer). The through-hole may be drilled using, for example, laser drilling equipment. 
     At step  194 , transparent filler material such as protective polymer or glass material may be provided in the through-hole and over the tri-acetyl cellulose layer. 
     At step  196 , optical enhancement materials such as an antireflection coating or other coating materials may be formed on the protective material. 
     At step  198 , the display polarizer with the protective-material-filled drilled opening that is filled with the transparent material may be attached to additional display structures such as a display color filter glass layer. 
       FIG. 18  is a diagram of drilling equipment  112  that may be used for drilling openings that pass partially or completely through display polarizer layers. As shown in  FIG. 18 , drilling equipment  112  may include (in addition to laser  134 , computer controlled positioning equipment  136 , aperture  130 , and lens  132  as described above in connection with  FIG. 9 ), computing equipment  208 , a monitor laser  202 , polarizer block  210 , and light sensor  212 . 
     Process laser  134  may emit a high frequency laser beam  200  that reflects from mirror  206  onto polarizer  62  and removes material from polarizer layers of polarizer  62  during drilling operations. Computing equipment  208  may be used to control process laser  134 , equipment  136 , monitor laser  202  and light sensor  212 . Monitor laser  202  may emit a laser beam such as optical laser beam  204  (e.g., a green-colored laser beam) that passes through polarizer  62 . Mirror  206  may be a beam splitting mirror that allows optical beam  204  to pass through mirror  206  onto polarizer  62 . Optical beam  204  may pass through polarizer block  210  and onto sensor  212 . Polarizer block  210  may be a polarizer that is oriented in a direction that is orthogonal to the orientation of polarization of PVA layer  68 . Computing equipment  208  may monitor the intensity of the portion of beam  204  that reaches sensor  212  during drilling operations for polarizer  62 . The amount of light from beam  204  that reaches sensor  212  will increase as PVA layer  68  is removed using process beam  200 . 
     Computing equipment  208  may determine when drilling operations are complete using the monitored intensity of the beam  204 . For example, computing equipment  208  may be configured to terminate drilling operations when the intensity of beam  204  reaches a predetermined threshold level (e.g., a threshold level determined using monitored light intensities from drilling operations for other polarizers or using predetermined measurements of the unattenuated intensity of beam  204 ) or when the change in intensity of beam  204  falls to or below a predetermined minimum rate of change. 
     Drilling equipment  112  of the type shown in  FIG. 18  may be used in forming any of openings  100 ,  101 ,  103  (see, e.g.,  FIGS. 8 ,  12 , and  15 ) or other openings for unpolarized windows in polarizers such as polarizer  62  of display  14  of device  10 . 
     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: 20121030
Publication Date: 20150707
Grant Date: 20150707
Priority Date: 20121030
Inventors: JIAO MEIZI
QI JUN
YIN VICTOR H.
Assignee: APPLE INC
CPC Classifications: [{"code": "G02B5/30", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F2001/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B5/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133528", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/041", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B5/3083", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/1056", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B5/3033", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F2001/13312", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B5/30", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/13312", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/13312", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B5/3033", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B5/3041", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B5/3033", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T156/1056", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B5/3083", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/041", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133528", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B5/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B5/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B5/3083", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/1056", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B5/30", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133528", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 50546886