PATENT DOCUMENT

Publication Number: US-8867015-B2
Application Number: US-201213348496-A
Country: US
Kind Code: B2

Title: Displays with liquid crystal shutters

Abstract:
An electronic device may have a display such as a liquid crystal display. The display may have an array of display pixels. The array of display pixels may display images for a user in an active area of the display. An inactive area of the display may surround the active area. An opaque masking layer may be provided in the inactive area to block internal components in the electronic device from view. An optical component such as a light-based proximity sensor, ambient light sensor, image sensor, or light-emitting status indicator may be aligned with an opening in the opaque masking layer. A liquid crystal shutter may be provided in the display. The liquid crystal shutter may be controlled by control circuitry in the electronic device. The liquid crystal shutter may be aligned with the opening in the opaque masking layer in the inactive area and with the optical component.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a display having an array of display pixels arranged to form an active area for the display in which images are displayed; 
 a liquid crystal shutter in an inactive area of the display; 
 an optical component aligned with the liquid crystal shutter, wherein the display comprises a first liquid crystal material in the array of display pixels and a second liquid crystal material in the liquid crystal shutter; 
 a color filter layer; and 
 a thin-film transistor layer, wherein the first liquid crystal material is interposed between the color filter layer and the thin-film transistor layer in the active area and wherein the second liquid crystal material is interposed between the color filter layer and the thin-film transistor layer in the inactive area. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the first and second liquid crystal materials are different materials. 
     
     
       3. The electronic device defined in  claim 1  further comprising at line of sealant that separates the first liquid crystal material from the second liquid crystal material. 
     
     
       4. The electronic device defined in  claim 1  further comprising a layer of opaque masking material in the inactive area. 
     
     
       5. The electronic device defined in  claim 4  wherein the layer of opaque masking material has an opening that is aligned with the liquid crystal shutter and the optical component. 
     
     
       6. The electronic device defined in  claim 5  wherein the optical component comprises at least one optical component selected from the group consisting of: a light-based proximity sensor, an ambient light sensor, a status indicator light, and a camera. 
     
     
       7. The electronic device defined in  claim 5  wherein the optical component comprises a camera and wherein the liquid crystal shutter is configured to operate in:
 a closed state in which the camera is blocked from view through the opening; and 
 an open state in which image light for the camera passes through the opening and the second liquid crystal material of the liquid crystal shutter. 
 
     
     
       8. The electronic device defined in  claim 7  further comprising control circuitry that is configured to place the liquid crystal shutter in the open state to acquire images with the camera. 
     
     
       9. The electronic device defined in  claim 1  further comprising control circuitry that controls operation of the liquid crystal shutter, wherein the liquid crystal shutter is configured to operate in:
 a closed state in which the optical component is blocked from view through the display; and 
 an open state in which light associated with the optical component passes through the display and the second liquid crystal material of the liquid crystal shutter. 
 
     
     
       10. An electronic device, comprising:
 a display having an array of display pixels arranged to form an active area for the display in which images are displayed; 
 a liquid crystal shutter in an inactive area of the display; and 
 an optical component aligned with the liquid crystal shutter, wherein the display comprises a color filter layer and a thin-film transistor layer and wherein the liquid crystal shutter is formed from liquid crystal material that lies between the color filter layer and the thin-film transistor layer in a portion of the inactive area. 
 
     
     
       11. The electronic device defined in  claim 10  wherein the liquid crystal shutter comprises an electrode and a thin-film transistor.

Description:
BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices with displays and optical components. 
     Electronic devices such as computers and cellular telephones may have displays. Computers and cellular telephones may also include optical components such as cameras. For example, a computer or cellular telephone may include a front-facing camera for use in videoconferencing sessions. 
     It can be challenging to accommodate optical components such as cameras in electronic devices with displays. 
     In some devices, a camera may be mounted under a circular hole in a plastic display bezel. The circular hole in the bezel in this type of arrangement is visible to the user and may detract from the appearance of the device. 
     To improve device aesthetics, a device may be provided with a display that has a black border with a hole to accommodate a camera. The black border may be formed from a layer of black masking material on the underside of a display cover glass. A device of this type need not include a plastic display bezel. Nevertheless, the presence of the hole in the black border region can be visually unappealing. 
     It would therefore be desirable to be able to provide improved ways in which to mount optical components such as cameras in electronic devices with displays. 
     SUMMARY 
     An electronic device may have a display. The display may have an array of display pixels. The array of display pixels may display images for a user in an active area of the display. The display may be a liquid crystal display that has a layer of liquid crystal material. The display pixels in the active area may be provided with electrodes that control electric fields that are applied to the liquid crystal material. 
     An inactive area of the display may surround the active area. An opaque masking layer may be provided in the inactive area to serve as a border that blocks internal components in the electronic device from view. 
     An optical component such as a light-based proximity sensor, ambient light sensor, camera, or light-emitting status indicator may be aligned with an opening in the opaque masking layer. A liquid crystal shutter may be provided in the display. The liquid crystal shutter may be controlled by control circuitry in the electronic device. The liquid crystal shutter may be aligned with the opening in the opaque masking layer in the inactive area and with the optical component. The control circuitry may open the liquid crystal shutter to allow light to pass through the opening to support operation of the optical component. The control circuitry may close the liquid crystal shutter when the optical component is not producing or receiving light. In its closed position, the liquid crystal shutter may have a dark appearance that matches the dark appearance of surrounding portions of the opaque masking layer and may block the optical components from vie through the opening 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 diagram of an illustrative electronic device such as a portable computer with a display and one or more optical components in accordance with an embodiment of the present invention. 
         FIG. 2  is a diagram of an illustrative electronic device such as a cellular telephone or other handheld device with a display and one or more optical components in accordance with an embodiment of the present invention. 
         FIG. 3  is a diagram of an illustrative electronic device such as a tablet computer with a display and one or more optical components in accordance with an embodiment of the present invention. 
         FIG. 4  is a diagram of an illustrative electronic device such as a computer monitor with a built-in computer having a display and one or more optical components in accordance with an embodiment of the present invention. 
         FIG. 5  is a schematic diagram of an illustrative electronic device with a display and one or more optical components in accordance with an embodiment of the present invention. 
         FIG. 6  is a circuit diagram of an illustrative display pixel in an array of pixels in an electronic device display in accordance with an embodiment of the present invention. 
         FIG. 7  is a diagram of an illustrative array of display pixels in the active area of an electronic device display in accordance with an embodiment of the present invention. 
         FIG. 8  is a circuit diagram of an illustrative optical component shutter formed using liquid crystal material in an inactive region of an electronic device display in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional side view of a portion of an electronic device in which a liquid crystal display shutter is in an opaque state and is being used to block one or more optical components from view by a user of the electronic device in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional side view of a portion of the electronic device of  FIG. 9  in a configuration in which the liquid crystal display shutter is in a transparent state and is allowing one or more optical components to send or receive light through the shutter in accordance with an embodiment of the present invention. 
         FIG. 11  is a top view of an illustrative display having an active region containing an array of display pixels that display images surrounded by an inactive region that has a liquid crystal shutter structure covering one or more optical components in accordance with an embodiment of the present invention. 
         FIG. 12  is a cross-sectional side view of a portion of the display in  FIG. 11  in the vicinity of the liquid crystal shutter in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative electronic device of the type that may be provided with a display and one or more optical components is shown in  FIG. 1 . Electronic device  10  may be a computer such as a computer that is integrated into a display such as a computer monitor, a laptop computer, a tablet computer, a somewhat smaller portable device such as a wrist-watch device, pendant device, or other wearable or miniature device, a cellular telephone, a media player, a tablet computer, a gaming device, a navigation device, a computer monitor, a television, or other electronic equipment. 
     As shown in  FIG. 1 , device  10  may include a display such as display  14 . Display  14  may be a touch screen that incorporates capacitive touch electrodes or other touch sensor components or may be a display that is not touch sensitive. Display  14  may include image pixels formed from liquid crystal display (LCD) components or other suitable display pixel structures. Arrangements in which display  18  is formed using liquid crystal display pixels are sometimes described herein as an example. This is, however, merely illustrative. Any suitable type of display technology may be used in forming display  14  if desired. 
     Device  10  may have a housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. 
     Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). 
     As shown in  FIG. 1 , housing  12  may have multiple parts. For example, housing  12  may have upper portion  12 A and lower portion  12 B. Upper portion  12 A may be coupled to lower portion  12 B using a hinge that allows portion  12 A to rotate about rotational axis  16  relative to portion  12 B. A keyboard such as keyboard  18  and a touch pad such as touch pad  20  may be mounted in housing portion  12 B. 
     Display  14  may have an active area such as active area AA and an inactive area such as area IA. Active area AA may be, for example, a rectangular region in the center of display  14  in which display pixels are actively used to display images for a user of device  10 . Inactive area IA may be devoid of active display pixels, but may contain one or more liquid crystal shutters for selectively hiding and uncovering one or more optical components. In the example of  FIG. 1 , inactive area IA has the shape of a rectangular ring, surrounding the periphery of active area AA of display  14 . 
     Circuitry and other components may sometimes be formed in inactive area IA. To hide the circuitry and other components from view by a user of device  10 , inactive area IA may sometimes be provided with an opaque mask. The opaque mask can be formed from an opaque material such as a black pigmented polymer material or may be formed from opaque masking materials of other colors. Configurations in which the opaque masking material in display  14  has a black appearance are sometimes described herein as an example. This is, however, merely illustrative. Opaque masking layers in device  10  may have any suitable colors. 
     In the example of  FIG. 2 , device  10  has been implemented using a housing that is sufficiently small to fit within a user&#39;s hand (i.e., device  10  of  FIG. 2  may be a handheld electronic device such as a cellular telephone). As show in  FIG. 2 , device  10  may include a display such as display  14  mounted on the front of housing  12 . Display  14  may be substantially filled with active display pixels or may have an inactive portion such as inactive portion IA that surrounds an active portion such as active portion AA. Display  14  may have openings (e.g., openings in inactive region IA or active region AA of display  14 ) such as an opening to accommodate button  22  and an opening to accommodate speaker port  24 . 
       FIG. 3  is a perspective view of electronic device  10  in a configuration in which electronic device  10  has been implemented in the form of a tablet computer. As shown in  FIG. 3 , display  14  may be mounted on the upper (front) surface of housing  12 . An opening may be formed in display  14  to accommodate button  22  (e.g., in inactive region IA surrounding active region AA). 
       FIG. 4  is a perspective view of electronic device  10  in a configuration in which electronic device  10  has been implemented in the form of a computer integrated into a computer monitor. As shown in  FIG. 4 , display  14  may be mounted on the front surface of housing  12 . Stand  26  may be used to support housing  12 . Display  14  may include an inactive region such as inactive region IA that surrounds active region AA. 
     If desired, display  14  may be configured so as to minimize or eliminate the size of inactive region IA along one or more edges of active region AA. Configurations in which inactive region IA extends along all four edges of a rectangular active region AA are described herein as an example. 
     A schematic diagram of an illustrative electronic device such as electronic device  10  of  FIG. 1  is shown in  FIG. 5 . As shown in  FIG. 5 , electronic device  10  may include control circuitry such as storage and processing circuitry  30 . Storage and processing circuitry  30  may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in storage and processing circuitry  30  may be used to control the operation of device  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio codec chips, application specific integrated circuits, display driver integrated circuits, etc. 
     Storage and processing circuitry  30  may be used to run software on device  10  such as internet browsing applications, voice-over-internet-protocol (VOIP) telephone call applications, email applications, media playback applications, operating system functions, etc. The software may be used to implement control operations such as image acquisition operations using a camera, ambient light measurements using an ambient light sensors, proximity sensor measurements using a proximity sensor, information display functions implemented using status indicators such as light-emitting-diode status indicators, touch event measurements using a touch sensor, functions associated with displaying information on multiple (e.g., layered) displays, operations associated with performing wireless communications functions, operations associated with gathering and producing audio signals, control operations associated with gathering and processing button press event data, operations associated with opening and closing optical shutters such as liquid crystal shutters formed in a display, and other functions in device  10 . 
     Input-output circuitry  42  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  42  may include optical components  32 . Optical components  32  may include cameras, ambient light sensors, light-based proximity sensors, light-emitting diode status indicators, and other equipment for producing and receiving light. 
     Input-output circuitry  42  may also include one or more displays such as display  14 . Display  14  may be a liquid crystal display, an organic light-emitting diode display, an electronic ink display, a plasma display, a display that uses other display technologies, or a display that uses any two or more of these display technologies. Display  14  may include an array of touch sensors (i.e., display  14  may be a touch screen) or may be insensitive to touch. The touch sensors in a touch sensitive arrangement for display  14  may be capacitive touch sensors formed from an array of transparent touch sensor electrodes such as indium tin oxide (ITO) electrodes or may be touch sensors formed using other touch technologies (e.g., acoustic touch, pressure-sensitive touch, resistive touch, optical touch, etc.). 
     Audio components  36  may be used to provide device  10  with audio input and output capabilities. Examples of audio components that may be included in device  10  include speakers, microphones, buzzers, tone generators, and other components for producing and detecting sound. 
     Communications circuitry  38  may be used to provide device  10  with the ability to communicate with external equipment. Communications circuitry  38  may include analog and digital input-output port circuitry and wireless circuitry based on radio-frequency signals and/or light. Wireless circuitry in communications circuitry  38  may include radio-frequency transceiver circuitry, power amplifier circuitry, low-noise amplifiers, switches, filters, and antennas. Wireless communications circuitry in circuitry  38  may, for example, include circuitry for supporting near field communications (NFC) by transmitting and receiving near-field-coupled electromagnetic signals. For example, circuitry  38  may include a near field communications antenna and a near field communications transceiver. Circuitry  38  may also include a cellular telephone transceiver and antennas, wireless local area network transceiver circuitry and antennas, etc. 
     Device  10  may also include a battery, power management circuitry, accelerometers, and other sensors, and other input-output devices  40 . Input-output devices  40  may include buttons, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, etc. 
     A user can control the operation of device  10  by supplying commands through input-output circuitry  42  and may receive status information and other output from device  10  using the output resources of input-output circuitry  42 . 
     Display  14  may be, for example, a liquid crystal display. Display  14  may include an array of pixels. Each pixel may be used to control the light intensity associated with a portion of the display in active area AA. 
       FIG. 6  is a circuit diagram of an illustrative display pixel in the pixel array of display  14 . Display  14  may have a set of data lines for supplying pixel image data to columns (or rows) of display pixels in the pixel array of display  14  and may have a set of gate lines for activating and deactivating rows (or columns) of display pixels during the process of displaying images on display  14 . Pixels such as pixel  50  of  FIG. 6  may be located at the intersection of each gate line and data line in display  14 . 
     A data signal D may be supplied to terminal  49  from one of the data lines in display  14 . Thin-film transistor  52  (e.g., a thin-film polysilicon transistor or an amorphous silicon transistor on a thin-film transistor substrate) may have a gate terminal such as gate  54  that receives gate line signal G from display driver circuitry (e.g., gate driver circuitry). When signal G is asserted, transistor  52  will be turned on and signal D will be passed to node  56  as voltage Vp. Data for display  14  may be displayed in frames. Following assertion of signal G in one frame, signal G may be deasserted. Signal G may then be asserted to turn on transistor  52  and capture a new value of Vp in a subsequent display frame. 
     Pixel  40  may have a signal storage element such as capacitor Cst or other charge storage element. Storage capacitor Cst may be used to store signal Vp between frames (i.e., in the period of time between the assertion of successive signals G). 
     Display  14  may have a common electrode coupled to node  58 . The common electrode (which is sometimes referred to as the Vcom electrode) may be used to distribute a common electrode voltage such as common electrode voltage Vcom to nodes such as node  58  in each pixel  50  of the pixel array in display  14 . Capacitor Cst may be coupled between nodes  56  and  58 . A parallel capacitance Clc arises across nodes  56  and  58  due to electrode structures in pixel  50  that are used in controlling the electric field through the liquid crystal material of the pixel (liquid crystal material  60 ). As shown in  FIG. 6 , electrode structures  62  may be coupled to node  56 . During operation, electrode structures  62  may be used to apply a controlled electric field across a pixel-sized portion of liquid crystal material  60  in pixel  50 . Due to the presence of storage capacitor Cst and the capacitance produced by electrode structures  62 , the value of Vp (and therefore the associated electric field across liquid crystal material  60 ) may be maintained across nodes  56  and  58  for the duration of the frame. Electrode structures  62  may have any suitable shape. For example, each display pixel may have an electrode that is formed from multiple electrode fingers. The material that is used in forming electrode structures (display pixel electrode)  62  may be, for example, a transparent conductive material such as indium tin oxide. 
     The electric field that is produced across liquid crystal material  60  causes a change in the orientations of the liquid crystals in liquid crystal material  60 . This changes the polarization of light passing through liquid crystal material  60 . The change in light polarization may be used in controlling the amount of light that is transmitted through each pixel  50  in active region AA of display  14 .  FIG. 7  is a diagram of an illustrative array of display pixels  50  in active region AA of display  14 . 
     To provide display  14  with the ability to display color images, active area AA of display  14  may be provided with color filter elements. For example, display  14  may be provided with color filter elements such as red, green, and blue elements. Each color filter element may be used to impart color to the light associated with a respective display pixel in the pixel array of display  14  ( FIG. 7 ). 
     Some or all of inactive region IA of display  14  may be provided with an opaque masking layer that blocks internal device components from view by a user of device  10 . One or more openings may be formed in the opaque masking layer to allow light from internal optical components to exit device  10  and to allow external light to enter device  10  for use by internal optical components. For example, an opaque masking layer in inactive region IA may be provided with one or more holes to accommodate a camera, ambient light sensor, light-based proximity sensor, status indicator light, and/or other optical components  32 . 
     To minimize the visual impact of openings in the opaque masking layer, each opening may be covered with a liquid crystal shutter structure. A circuit diagram of an illustrative liquid crystal shutter is shown in  FIG. 8 . As shown in  FIG. 8 , a first voltage V 1  (e.g., a positive voltage) may be supplied to terminal  76  and a second voltage V 2  (e.g., a ground voltage or a positive or negative voltage) may be supplied to terminal  78 . Thin-film transistor  72  may be a thin-film polysilicon transistor or an amorphous silicon transistor and may be formed on the same thin-film transistor substrate one which thin-film transistors such as transistor  52  of  FIG. 6  are formed. Transistor  72  may have a gate terminal such as gate  74  that receives a shutter control signal from control circuitry such as storage and processing circuitry  30  ( FIG. 5 ). Using the shutter control signal, transistor  52  may be turned on and off. 
     When transistor  72  is turned on, voltage V 1  will be applied node  80 . As shown in  FIG. 8 , electrode structures  82  may be coupled to node  80 . During operation of shutter  64 , electrode structures  82  may be used to apply a controlled electric field across liquid crystal shutter material  84  in shutter  64 . Electrode structures  82  may have any suitable shape. For example, electrode  82  may be formed from one or more electrode fingers. The material that is used in forming electrode  82  may be, for example, a transparent conductive material such as indium tin oxide. 
     The electric field that is produced across liquid crystal material  84  causes a change in the orientations of the liquid crystals in liquid crystal material  84 . This changes the polarization of light passing through liquid crystal material  84 . The change in light polarization may be used in controlling the amount of light that is transmitted through shutter  64  in inactive region IA of display  14 . 
     Operation of a liquid crystal shutter structure for display  14  such as shutter  64  of  FIG. 8  is illustrated in  FIGS. 9 and 10 . 
       FIGS. 9 and 10  are cross-sectional side views of a portion of device  10  in the vicinity of an opening in inactive area IA that has been provided with a liquid crystal shutter  64 . Shutter  64  may be formed in inactive portion IA of display  14  in alignment with optical component  32 . A single shutter is shown in the examples of  FIGS. 9 and 10 , but, in general, there may be two or more shutters and two or more associated optical components in device  10 . Control circuitry in device  10  such as storage and processing circuitry  30  of  FIG. 2  may be used to control the state of shutter  64  during operation of optical components  32  (e.g., to open shutter  64  to allow images to be acquired by a camera, etc.). 
     In  FIG. 9 , shutter  64  is in a closed state. In this state, shutter  64  may have an opaque (e.g., black) appearance. Shutter  64  may, for example, have a black appearance that matches surrounding black masking material in display  14 . Because shutter  64  is in an opaque state, light  66  will not readily pass through shutter  64 . As a result, shutter  64  will block internal device structures such as optical components  32  from view from the exterior of device  10 . 
     In  FIG. 10 , shutter  64  is in an open state. In this state, shutter  64  may have a transparent (clear) appearance. Because shutter  64  is in a transparent state, light such as light  66  can pass through shutter  64  from the exterior of device  10  to the interior of device  10  and can reach internal components such as optical components  32 . Light  72  that is produced by optical components  32  may also pass through shutter  64 . 
     Optical component(s)  32  may include one or more components that produce and/or receive light. 
     Optical component(s)  32  may include one or more light-based proximity sensors. A light-based proximity sensor may, for example, include a light-emitting diode that that emits infrared light or light of other wavelengths. The emitted light may pass through shutter  64  when shutter  64  is in the open position of  FIG. 10 , as indicated by light  72 . In the presence of nearby external objects, the emitted light may be reflected back through shutter  64 , as indicated by light  66  in  FIG. 10 . The light-based proximity sensor may include a light sensor that measures the magnitude of reflected light to determine whether or not an external object is in the vicinity of the light-based proximity sensor. 
     Optical component(s)  32  may also include one or more light-based status indicators. A light-based status indicator may be implemented using one or more light-emitting diodes or other light sources capable of emitting light with an intensity and/or pattern that conveys information to a user. As an example, a status indicator component may be formed from one or more light-emitting diodes of one or more different colors. The status indicator light-emitting diodes may be used for indicating on/off status (power status), sleep/wake status, battery charging status, or other status information. The emitted light from the status indicator may pass through shutter  64  when shutter  64  is in its open configuration, as shown by light  72  of  FIG. 10 . 
     Optical component(s)  32  may include light detecting components such as one or more ambient light sensors. An ambient light sensor may include one or more semiconductor light detectors. The light detectors may be used to measure ambient lighting conditions for device  10 . To make a light measurement, shutter  64  may be placed in its open state ( FIG. 10 ), so that ambient light  66  may be received and measured by the detector structures associated with the ambient light sensor. 
     If desired, optical component(s)  32  may include one or more images sensors. For example, optical component(s)  32  may include an image sensor that has been packaged with a lens to form a camera (sometimes referred to as a camera module) or may contain other optical structures that are capable of capturing digital images for device  10 . The camera may be mounted so that lens structures are pointing outwards through shutter  64 . When shutter  64  is placed in its open configuration by the control circuitry of device  10 , image light from an external object may be received by the camera through shutter  64 , as indicated by light  66  of  FIG. 10 . The camera may convert the incoming image light into digital image data for use by the storage and processing circuitry of device  10 . 
     When optical component(s)  32  are not being actively used (e.g., during moments in time in which light  72  is not being emitted and in which light  66  is not being received), shutter  64  may be placed in its closed position by the control circuitry of device  10 , so that optical components  32  are hidden from view in direction  68  ( FIG. 9 ) by a user of device  10 . 
       FIG. 11  is a front view of display  10  showing structures that may be used in implementing an illustrative liquid crystal shutter for display  14 . In the illustrative configuration of  FIG. 11 , active area AA of display  14  has a rectangular shape that lies in the center of the surface of display  14  and inactive area IA has a rectangular ring shape that forms a peripheral border around all of the four edges of active area AA. In active area AA, display pixels such as display pixels  50  of  FIG. 6  may be arranged to form a display pixel array such as the array of pixels in  FIG. 7 . The array of display pixels in active area AA may be controlled by control circuitry in device  10  (e.g., a display driver integrated circuit and other control circuitry) so that display  14  can be used to display images for a user. 
     Inactive area IA serves as a border region surrounding the periphery of active area AA. Components such as display driver circuits, antennas, signal buses, connectors, alignment marks, and other structures may be located under inactive area IA. To hide these structures from view, inactive area IA may be covered using an opaque masking material such as a black pigmented polymer, a sheet of black plastic, or other opaque masking structures. As an example, a layer of cover glass, a color filter layer, or other display layer in display  14  may be coated with a black masking material in inactive area IA. The black masking material may be formed on the underside (inner surface) of a display cover glass or other suitable display surface (as an example). Active area AA may have a black matrix formed from thin horizontal and vertical lines of black masking material. Openings in the black matrix may be provided with color filter elements that allow colored light from the display pixel array to be emitted for viewing by a user. Active area AA may otherwise be devoid of black masking material. In inactive area AA, the black masking material may be patterned to form a black border surrounding active area AA. 
     Openings such as opening  90  may be formed in the black masking material within inactive area IA. Openings such as opening  90  may be used to allow light such as light  66  and  72  to pass through display  14 . One or more different types of liquid crystal structure (e.g., liquid crystal layers containing different liquid crystals, different layer thicknesses, or other attributes) may be used in display  14 . In the example of  FIG. 11 , two different types of liquid crystal structure are being used in display  14 : liquid crystal material LC 1  and liquid crystal material LC 2 . 
     Lines of sealant  92  and  94  may be used to seal liquid crystal material within desired regions of display  14 . As shown in  FIG. 11 , for example, liquid crystal material LC 1  (i.e., liquid crystal material  60  of  FIG. 6 ) may be used in the display pixels in active area AA (e.g., display pixels such as display pixels  50  of  FIGS. 6 and 7 ) and may be contained within active area AA by sealant  94  (and a portion of sealant  92 ). Liquid crystal material LC 2  (i.e., liquid crystal material  84  of shutter  64  of  FIG. 8 ) may be confined within an area that overlaps opening  90  in inactive region IA. As shown in  FIG. 11 , the outline of the region in which liquid crystal material LC 1  is confined may be surrounded by adjacent portions of sealant lines  92  and  94 . Sealant lines  92  and  94  may be formed from any suitable material such as epoxy or other adhesives. 
       FIG. 12  is a cross-sectional side view of display  14  of  FIG. 11  taken along line  98  in  FIG. 11  and viewed in direction  100 . As shown in  FIG. 12 , sealant  92  and  94  may be interposed between display layers such as color filter layer  102  and thin-film transistor layer  104 . 
     Color filter layer  102  may include color filter elements  108  formed on a substrate layer such as color filter substrate layer  106 . Color filter substrate layer  106  may be formed from clear plastic, clear glass, or other transparent material. Color filter elements  108  may be formed in an array (e.g., an array of alternating red, green, and blue color filter elements) and may therefore sometimes be referred to as a color filter array or color filter array structures. The illustrative color filter array of  FIG. 12  has red (R), green (G), and blue (B) elements aligned with respective display pixels  50  in thin-film transistor layer  104 . Black matrix material  110  in active area AA may be interposed between adjacent color filter elements  108 . 
     In inactive area IA, black masking material  112  may form a black border for display  14 . Opening  90  may be formed from a circular hole, a rectangular hole, or an opening of other suitable shapes in black masking material  112 . Liquid crystal material LC 2  for shutter  64  may be interposed between respective sealant borders  94  and  92  and may overlap liquid crystal shutter structures  64  on thin-film transistor layer substrate  114  in thin-film transistor layer  104 . Substrate  114  may be formed form a clear plastic layer, a clear glass layer, or other transparent substrate material. When shutter  64  is in its open configuration, light  66  may be received by one or more optical components  32  through opening  90  in black masking layer  112  and shutter  64  and light produced by one or more optical components  32  may pass through shutter  64  and opening  90 . 
     In active region AA, backlight  55  for display  14  may be provided by backlight unit  120 . Backlight unit  120  may include a transparent light guide plate. A light source such as an array of light-emitting diodes may emit light into one or more edges of the light guide plate. The light guide plate may distribute light over the rear surface of display  14  in active area AA. A reflector on the lower surface of the light guide plate may help reflect light that has leaked downwards back in an upwards direction to serve as backlight  55 . 
     Display  14  may include upper polarizer  118  and lower polarizer  116 . During operation, control circuitry may control the array of display pixels  50  to adjust the electric fields that are produced by display pixels  50  in liquid crystal layer LC 1 . These electric field adjustments may rotate different pixels of liquid crystal material LC 1  by different amounts, thereby rotating the polarization of backlight  55  that is traveling through liquid crystal material LC 1  by different amounts. In combination with upper and lower polarizers  116  and  118 , adjustment of the polarization of backlight  55  that is traveling through liquid crystal layer LC 1  liquid crystal will create images for viewing by a user of device  10 . 
     When shutter  64  is in its open position, one or more optical components  32  may emit and receive light through shutter  64 . To ensure that excess light is not absorbed by liquid crystal material  64 , it may be desirable to configure liquid crystal material LC 2  to ensure satisfactory light transmission. As an example, liquid crystal material LC 2  may be provided with a thinner thickness and/or may be formed from a liquid crystal material that exhibits a higher maximum transmission than liquid crystal material LC 1 . 
     When shutter  64  is in its closed position, the electrode in shutter  64  may apply an electric field to liquid crystal material LC 2  that orients liquid crystal material LC 2  so that (in combination with upper polarizer  118  and lower polarizer  116 ), liquid crystal material LC 2  blocks light transmission. In this situation, liquid crystal shutter  64  may have a black appearance that matches the black color of surrounding portions of black masking layer  112 , thereby ensuring that display  14  has an uncluttered and aesthetically appealing appearance in inactive region IA. 
     If desired, display  14  of  FIG. 12  may be provided with additional display layers. For example, display  14  may be provided with a cover layer such as a layer of cover glass. The cover glass may have a black peripheral border portion that is aligned with inactive area IA. Display  14  may also have anti-smudge layers, antireflection coating layers, anti-scratch layers, layers that perform two or more of these functions or other suitable functions, etc. The display layers of display  14  of  FIG. 12  are shown as an example. Other display configurations may be provided with controllable shutter structures such as liquid crystal shutter  64 , if desired. 
     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: 20120111
Publication Date: 20141021
Grant Date: 20141021
Priority Date: 20120111
Inventors: POSNER BRYAN W.
QI JUN
YIN VICTOR H.
WILSON, JR. THOMAS W.
MATHEW DINESH C.
HENDREN KEITH J.
AUGENBERGS PETERIS K.
GARELLI ADAM T.
MCCLURE STEPHEN R.
PETERSON CARL R.
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F1/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/1333", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/1333", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 48743701