PATENT DOCUMENT

Publication Number: US-9335510-B2
Application Number: US-201213631125-A
Country: US
Kind Code: B2

Title: Display with electromechanical mirrors for minimizing display borders

Abstract:
An electronic device may be provided with a display mounted in a housing. The display may have an array of display pixels that provide light to a user. The array of display pixels may form active display structures with a rectangular shape. The rectangular active display structures may be surrounded by an inactive border region. Reflector structures may be used to reflect light that is emitted from peripheral portions of the active display structures to a portion of the display overlapping the inactive border region, thereby providing the display with an effective active area that is larger than the area of the active display structures. The reflector structures may include rotatable reflectors. Control circuitry may use a rotatable positioner to rotate rotatable reflector structures in synchronization with controlling which pixel data is displayed by the display pixels in the peripheral portions of the active display structures.

Claims:
What is claimed is: 
     
       1. A display for displaying content with an apparent size to a user, the display comprising:
 active display structures having a central region of display pixels and a peripheral edge region of display pixels; 
 adjustable reflecting structures that reflect light from the display pixels in the peripheral edge region to make the apparent size of the display larger than the area of the active display structures, wherein the adjustable reflecting structures comprise a reflector and a positioner that rotates the reflector; and 
 control circuitry configured to control the active display structures and the adjustable reflecting structures. 
 
     
     
       2. The display defined in  claim 1  wherein the active display structures include an array of display pixels with a rectangular periphery and wherein the adjustable reflecting structures are located along at least part of the rectangular periphery. 
     
     
       3. The display defined in  claim 2  wherein the adjustable reflecting structures comprise electromechanical mirror structures. 
     
     
       4. The display defined in  claim 3  further comprising a stationary reflector configured to reflect the light to the adjustable reflecting structures from the display pixels in the peripheral edge region. 
     
     
       5. The display defined in  claim 4  wherein the stationary reflector comprises a mirror. 
     
     
       6. The display defined in  claim 5  wherein the mirror has a non-planar surface. 
     
     
       7. The display defined in  claim 4  wherein the stationary reflector comprises a prism. 
     
     
       8. The display defined in  claim 3  wherein the reflector comprises a mirror with a non-planar surface. 
     
     
       9. The display defined in  claim 1  wherein the peripheral edge region of display pixels has a display pixel width of at least two display pixels. 
     
     
       10. A display, comprising:
 display structures having a first set of active display pixels and a second set of active display pixels; and 
 adjustable reflector structures that reflect light from the second set of active display pixels without reflecting light from the first set of display pixels to reduce visible inactive display borders, wherein the adjustable reflector structures comprise a reflector and a positioner that rotates the reflector. 
 
     
     
       11. The display defined in  claim 10  wherein the adjustable reflector structures comprise a stationary reflector. 
     
     
       12. The display defined in  claim 10  wherein the second set of active display pixels displays pixels in synchronization with movement of the reflector by the positioner. 
     
     
       13. The display defined in  claim 10  wherein the first set of active display pixels comprises an array of display pixels lying in a plane and wherein the second set of active display pixels includes at least some pixels on a bent edge portion of the display pixels that lies out of the plane. 
     
     
       14. The display defined in  claim 10  wherein the display structures comprise organic-light-emitting diode display structures with a bent edge on which the second set of active display pixels is formed. 
     
     
       15. The display defined in  claim 10  wherein the display structures include a display pixel array, wherein the first set of display pixels forms a central portion of the display pixels in the display pixel array, wherein the second set of display pixels forms peripheral display pixels that surround the central portion of the display, and wherein the reflector comprises an electromechanical mirror. 
     
     
       16. The display defined in  claim 1 , wherein the control circuitry is configured to direct at least one pixel in the peripheral edge region of the display pixels to alternately display first pixel data and second pixel data. 
     
     
       17. A display for displaying content with an apparent size to a user, the display comprising:
 active display structures having a central region of display pixels and a peripheral edge region of display pixels; 
 adjustable reflecting structures that reflect light from the display pixels in the peripheral edge region to make the apparent size of the display larger than the area of the active display structures, wherein the adjustable reflecting structures comprise a reflector and a positioner that rotates the reflector; and 
 control circuitry configured to control the active display structures and the adjustable reflecting structures, wherein the control circuitry is configured to direct at least one pixel in the peripheral edge region of the display pixels to alternately display first pixel data and second pixel data, wherein the control circuitry is configured to alternately adjust the adjustable reflecting structures between a first position and a second position that is different than the first position, wherein the first pixel data from the at least one pixel is reflected to a first location when the adjustable reflecting structures are in the first position, and wherein the second pixel data from the at least one pixel is reflected to a second location that is different than the first location when the adjustable reflecting structures are in the second position.

Description:
BACKGROUND 
     This relates generally to electronic devices, and more particularly, to electronic devices with displays. 
     Electronic devices often include displays. For example, cellular telephones and portable computers often include displays for presenting information to a user. An electronic device may have a housing such as a housing formed from plastic or metal. Components for the electronic device such as display components may be mounted in the housing. 
     It can be challenging to incorporate a display into the housing of an electronic device. Size and weight are often important considerations in designing electronic devices. If care is not taken, displays may be bulky or may be surrounded by overly large borders. The housing of an electronic device can be adjusted to accommodate a bulky display with large borders, but this can lead to undesirable enlargement of the size and weight of the housing and unappealing device aesthetics. 
     It would therefore be desirable to be able to provide improved displays for electronic devices. 
     SUMMARY 
     An electronic device may be provided with a display mounted in a housing. The display may have an array of display pixels that provide light to a user. The array of display pixels may form an active display structure with a rectangular shape. The rectangular active display structure may be surrounded by an inactive border region. Reflector structures may be provided around the periphery of the display structure. The reflector structures may be used to reflect light that is emitted from peripheral portions of the active display structure to a portion of the display overlapping the inactive border region, thereby providing the display with an effective area that is larger than the area of the active display structures. 
     The active display structures may have portions such as bent edge portions that emit light that is reflected by a fixed reflector or other reflector structures. The reflector structures may, for example, include a rotatable reflector. Control circuitry may use a rotatable positioner to rotate the rotatable reflector while simultaneously with controlling which pixel data is displayed by the display pixels in the peripheral portions of the active display structure. This allows pixel data to be distributed across the portion of the display that overlaps the inactive border region. 
     Display pixels may, if desired, be provided with enhanced brightness in the peripheral portion of active display structures to compensate for the use of the rotatable reflector to distribute display pixel light across multiple display locations. Curved or other non-planar surfaces may be used in the reflector structures. 
     An imaging system may use rotatable reflector structures to enhance the area of an image sensor used to capture digital image data. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device such as a laptop computer with a display in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view of an illustrative electronic device such as a handheld electronic device with a display in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view of an illustrative electronic device such as a tablet computer with a display in accordance with an embodiment of the present invention. 
         FIG. 4  is a schematic diagram of an illustrative electronic device with a display in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an illustrative display in accordance with an embodiment of the present invention. 
         FIG. 6  is a top view of illustrative display layers in a display having an active region with an array of display pixels and an inactive border region in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of an illustrative electronic device with an electromechanical mirror to distribute light from pixels in the edge of a display to minimize display borders in accordance with an embodiment of the present invention. 
         FIG. 8  is a set of graphs showing how pixel content may be modulated and mirror position synchronously adjusted to distribute light from pixels in the edge of a display to minimize display borders in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional side view of an illustrative electronic device with an electromechanical mirror to distribute light from multiple pixels in the edge of a display in parallel to minimize display borders in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional side view of an illustrative display with a bent edge portion and an electromechanical mirror to distribute light from multiple pixels in the bent edge portion along the edge of a display to minimize display borders in accordance with an embodiment of the present invention. 
         FIG. 11  is a cross-sectional side view of an illustrative display with a bent edge portion and a stationary mirror to distribute light from multiple pixels in the bent edge portion along the edge of a display to minimize display borders in accordance with an embodiment of the present invention. 
         FIG. 12  is a cross-sectional side view of an illustrative display with an electromechanical mirror in a first of three positions during the process of distributing light along the edge of a display to minimize display borders in accordance with an embodiment of the present invention. 
         FIG. 13  is a cross-sectional side view of the illustrative display of  FIG. 12  in which the electromechanical mirror is in a second of three positions during the process of distributing light along the edge of a display to minimize display borders in accordance with an embodiment of the present invention. 
         FIG. 14  is a cross-sectional side view of the illustrative display of  FIG. 12  in which the electromechanical mirror is in a third of three positions during the process of distributing light along the edge of a display to minimize display borders in accordance with an embodiment of the present invention. 
         FIG. 15  is a cross-sectional side view of an illustrative display with an electromechanical mirror and a stationary mirror of the type that may be provided with optional non-planar surfaces for use in distributing light from pixels along the edge of a display to minimize display borders in accordance with an embodiment of the present invention. 
         FIG. 16  is a cross-sectional side view of an illustrative image sensor system having an electromechanical mirror for enlarging the effective lateral dimensions of a digital image sensor in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may include displays. The displays may be used to display images to a user. Illustrative electronic devices that may be provided with displays are shown in  FIGS. 1, 2, and 3 . 
       FIG. 1  shows how electronic device  10  may have the shape of a laptop computer having upper housing  12 A and lower housing  12 B with components such as keyboard  16  and touchpad  18 . Device  10  may have hinge structures  20  that allow upper housing  12 A to rotate in directions  22  about rotational axis  24  relative to lower housing  12 B. Display  14  may be mounted in upper housing  12 A. Upper housing  12 A, which may sometimes referred to as a display housing or lid, may be placed in a closed position by rotating upper housing  12 A towards lower housing  12 B about rotational axis  24 . 
       FIG. 2  shows how electronic device  10  may be a handheld device such as a cellular telephone, music player, gaming device, navigation unit, or other compact device. In this type of configuration for device  10 , housing  12  may have opposing front and rear surfaces. Display  14  may be mounted on a front face of housing  12 . Display  14  may, if desired, have a display cover layer or other exterior layer that includes openings for components such as button  26 . Openings may also be formed in a display cover layer or other display layer to accommodate a speaker port (see, e.g., speaker port  28  of  FIG. 2 ). 
       FIG. 3  shows how electronic device  10  may be a tablet computer. In electronic device  10  of  FIG. 3 , housing  12  may have opposing planar front and rear surfaces. Display  14  may be mounted on the front surface of housing  12 . As shown in  FIG. 3 , display  14  may have a cover layer or other external layer with an opening to accommodate button  26  (as an example). 
     The illustrative configurations for device  10  that are shown in  FIGS. 1, 2, and 3  are merely illustrative. In general, electronic device  10  may be a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of these devices, or other electronic equipment. 
     Housing  12  of device  10 , which is sometimes referred to as a case, may be formed of materials such as plastic, glass, ceramics, carbon-fiber composites and other fiber-based composites, metal (e.g., machined aluminum, stainless steel, or other metals), other materials, or a combination of these materials. Device  10  may be formed using a unibody construction in which most or all of housing  12  is formed from a single structural element (e.g., a piece of machined metal or a piece of molded plastic) or may be formed from multiple housing structures (e.g., outer housing structures that have been mounted to internal frame elements or other internal housing structures). 
     Display  14  may be a touch sensitive display that includes a touch sensor or may be insensitive to touch. Touch sensors for display  14  may be formed from an array of capacitive touch sensor electrodes, a resistive touch array, touch sensor structures based on acoustic touch, optical touch, or force-based touch technologies, or other suitable touch sensor components. 
     Displays for device  10  may, in general, include image pixels formed from light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electrowetting pixels, electrophoretic pixels, liquid crystal display (LCD) components, or other suitable image pixel structures. In some situations, it may be desirable to use LCD components to form display  14 , so configurations for display  14  in which display  14  is a liquid crystal display are sometimes described herein as an example. It may also be desirable to provide displays such as display  14  with backlight structures, so configurations for display  14  that include a backlight unit may sometimes be described herein as an example. Other types of display technology may be used in device  10  if desired. The use of liquid crystal display structures and backlight structures in device  10  is merely illustrative. 
     A display cover layer may cover the surface of display  14  or a display layer such as a color filter layer or other portion of a display may be used as the outermost (or nearly outermost) layer in display  14 . A display cover layer or other outer display layer may be formed from a transparent glass sheet, a clear plastic layer, or other transparent structures. 
     Touch sensor components such as an array of capacitive touch sensor electrodes formed from transparent materials such as indium tin oxide may be formed on the underside of a display cover layer, may be formed on a separate display layer such as a glass or polymer touch sensor substrate, or may be integrated into other display layers (e.g., substrate layers such as a thin-film transistor layer). 
     A schematic diagram of an illustrative configuration that may be used for electronic device  10  is shown in  FIG. 4 . As shown in  FIG. 4 , electronic device  10  may include control circuitry  29 . Control circuitry  29  may include storage and processing circuitry for controlling the operation of device  10 . Control circuitry  29  may, for example, include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Control circuitry  29  may include processing circuitry based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio codec chips, application specific integrated circuits, etc. 
     Control circuitry  29  may be used to run software on device  10 , such as operating system software and application software. Using this software, control circuitry  29  may present information to a user of electronic device  10  on display  14 . Display  14  may contain an array of display pixels (e.g., liquid crystal display pixels) that are organized in rows and columns. Control circuitry  29  may be used to display content for a user of device  10  on the array of display pixels in display  14 . 
     Control circuitry  29  may include display driver circuitry and other circuitry for controlling the rate at which display pixels are refreshed and for controlling which pixel data is displayed by each display pixel. Display driver circuitry may be formed using thin-film-transistor circuitry on display  14  and/or integrated circuits mounted on a layer in display  14  or on a printed circuit. In addition to controlling the display of pixel data using the display pixels of display  14 , control circuitry  29  may perform control operations within device  10  such as controlling the positions of movable mirrors such as electromechanical mirrors and other controllable electronic components. Control circuitry  29  may, for example, issue control commands that direct a movable mirror to move to a desired position. Mirror adjustments such as these may be synchronized with display control operations (e.g., to ensure that electromechanical mirrors are positioned as desired in synchronization with the operation of display pixels in display  14 ). 
     Input-output circuitry  30  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output circuitry  30  may include communications circuitry  32 . Communications circuitry  32  may include wired communications circuitry for supporting communications using data ports in device  10 . Communications circuitry  32  may also include wireless communications circuits (e.g., circuitry for transmitting and receiving wireless radio-frequency signals using antennas). 
     Input-output circuitry  30  may also include input-output devices  34 . A user can control the operation of device  10  by supplying commands through input-output devices  34  and may receive status information and other output from device  10  using the output resources of input-output devices  34 . 
     Input-output devices  34  may include sensors and status indicators  36  such as an ambient light sensor, a proximity sensor, a temperature sensor, a pressure sensor, a magnetic sensor, an accelerometer, and light-emitting diodes and other components for gathering information about the environment in which device  10  is operating and providing information to a user of device  10  about the status of device  10 . 
     Audio components  38  may include speakers and tone generators for presenting sound to a user of device  10  and microphones for gathering user audio input. 
     Display  14  (e.g., the array of display pixels in display  14 ) may be used to present images for a user such as text, video, and still images. Sensors  36  may include a touch sensor array that is formed as one of the layers in display  14 . 
     User input may be gathered using buttons and other input-output components  40  such as touch pad sensors, buttons, joysticks, click wheels, scrolling wheels, touch sensors such as sensors  36  in display  14 , key pads, keyboards, vibrators, cameras, and other input-output components. 
     A cross-sectional side view of an illustrative configuration that may be used for display  14  of device  10  (e.g., for display  14  of the devices of  FIG. 1 ,  FIG. 2 , or  FIG. 3  or other suitable electronic devices) is shown in  FIG. 5 . As shown in  FIG. 5 , display  14  may include backlight structures such as backlight unit  42  for producing backlight  44 . During operation, backlight  44  travels outwards (vertically upwards in dimension Z in the orientation of  FIG. 5 ) and passes through display pixel structures in display layers  46 . This illuminates any images that are being produced by the display pixels for viewing by a user. For example, backlight  44  may illuminate images on display layers  46  that are being viewed by viewer  48  in direction  50 . 
     Display  14  may, if desired, have one or more optical structures that are located above display layers  46 . For example, display  14  may have a display cover layer such as display cover layer  84 . Display cover layer  84  may be formed from a layer of clear glass, a transparent sheet of plastic, or other transparent structure. Display cover layer  84  may be mounted in housing  12  (e.g., using housing sidewalls). During operation, light  44  may pass through the array of display pixels formed from display layers  46  and display cover layer  84  for viewing by user  48 . 
     Display layers  46  may be mounted in chassis structures such as a plastic chassis structure and/or a metal chassis structure to form a display module for mounting in housing  12  or display layers  46  may be mounted directly in housing  12  (e.g., by stacking display layers  46  into a recessed portion in housing  12 ). Display layers  46  may form a liquid crystal display or may be used in forming displays of other types. Display layers  46  may sometimes be referred to as a display module, a display, or an array of display pixels. The light (light  44 ) that passes through the array of display pixels is used in displaying content on display  14  for user  48 . 
     In a configuration in which display layers  46  are used in forming a liquid crystal display, display layers  46  may include a liquid crystal layer such a liquid crystal layer  52 . Liquid crystal layer  52  may be sandwiched between display layers such as display layers  58  and  56 . Layers  56  and  58  may be interposed between lower polarizer layer  60  and upper polarizer layer  54 . 
     Layers  58  and  56  may be formed from transparent substrate layers such as clear layers of glass or plastic. Layers  56  and  58  may be layers such as a thin-film transistor layer and/or a color filter layer. Conductive traces, color filter elements, transistors, and other circuits and structures may be formed on the substrates of layers  58  and  56  (e.g., to form a thin-film transistor layer and/or a color filter layer). Touch sensor electrodes may also be incorporated into layers such as layers  58  and  56  and/or touch sensor electrodes may be formed on other substrates. 
     With one illustrative configuration, layer  58  may be a thin-film transistor layer that includes an array of thin-film transistors and associated electrodes (display pixel electrodes) for applying electric fields to liquid crystal layer  52  and thereby displaying images on display  14 . Layer  56  may be a color filter layer that includes an array of color filter elements for providing display  14  with the ability to display color images. If desired, layer  58  may be a color filter layer and layer  56  may be a thin-film transistor layer. 
     During operation of display  14  in device  10 , control circuitry  29  (e.g., one or more integrated circuits such as components  68  on printed circuit  66  of  FIG. 5 ) may be used to generate information to be displayed on display  14  (e.g., display data). The information to be displayed may be conveyed from circuitry  68  to display control circuitry such as display driver integrated circuit  62  using a signal path such as a signal path formed from conductive metal traces in flexible printed circuit  64  (as an example). 
     Display driver integrated circuit  62  may be mounted on thin-film-transistor layer driver ledge  82  or elsewhere in device  10 . During operation of display  14 , display driver circuitry  62  and/or other display control circuitry such as gate driver circuitry formed on substrate  58  or coupled to substrate  58  may be used in controlling the array of display pixels in layers  46  (e.g., using a grid of vertical data lines and horizontal gate lines). 
     A flexible printed circuit cable such as flexible printed circuit  64  may be used in routing signals between printed circuit  66  and thin-film-transistor layer  58 . If desired, display driver integrated circuit  62  may be mounted on printed circuit  66  or flexible printed circuit  64 . Printed circuit  66  may be formed from a rigid printed circuit board (e.g., a layer of fiberglass-filled epoxy) or a flexible printed circuit (e.g., a flexible sheet of polyimide or other flexible polymer layer). 
     Backlight structures  42  may include a light guide plate such as light guide plate  78 . Light guide plate  78  may be formed from a transparent material such as clear glass or plastic. During operation of backlight structures  42 , a light source such as light source  72  may generate light  74 . Light source  72  may be, for example, an array of light-emitting diodes. 
     Light  74  from light source  72  may be coupled into edge surface  76  of light guide plate  78  and may be distributed in dimensions X and Y throughout light guide plate  78  due to the principal of total internal reflection. Light guide plate  78  may include light-scattering features such as pits or bumps. The light-scattering features may be located on an upper surface and/or on an opposing lower surface of light guide plate  78 . 
     Light  74  that scatters upwards in direction Z from light guide plate  78  may serve as backlight  44  for display  14 . Light  74  that scatters downwards may be reflected back in the upwards direction by reflector  80 . Reflector  80  may be formed from a reflective material such as a layer of white plastic or other shiny materials. 
     To enhance backlight performance for backlight structures  42 , backlight structures  42  may include optical films  70 . Optical films  70  may include diffuser layers for helping to homogenize backlight  44  and thereby reduce hotspots, compensation films for enhancing off-axis viewing, and brightness enhancement films (also sometimes referred to as turning films) for collimating backlight  44 . Optical films  70  may overlap the other structures in backlight unit  42  such as light guide plate  78  and reflector  80 . For example, if light guide plate  78  has a rectangular footprint in the X-Y plane of  FIG. 5 , optical films  70  and reflector  80  may have a matching rectangular footprint. Display layers  46  and the other display structures of  FIG. 5  typically have rectangular shapes with four peripheral edges, but display configurations with other shapes may be used in forming display  14  if desired. 
     As shown in  FIG. 6 , display structures  46  of display  14  may include a plurality of display pixels  86 . Display pixels  86  may be organized in rows and columns. Display control circuitry may be used in controlling the operation of display pixels  86  using signal lines such as data lines  88  and gate lines  90 . In liquid crystal displays, display pixels  86  may each contain an electrode for applying an electric field to an associated portion of liquid crystal layer  52  ( FIG. 5 ) and a thin-film (amorphous silicon or polysilicon) transistor for controlling the magnitude of the signal applied to the electrode and therefore the magnitude of the electric field. In other types of displays, display pixels  86  may be formed from other types of structures (e.g., organic light-emitting diodes, etc.). 
     Lines  90  may be coupled to the gates of the thin-film transistors and may sometimes be referred to as gate lines. Lines  88  may be coupled to the sources of the thin-film transistors and may sometimes be referred to as source lines or data lines. Gate driver circuitry (e.g., thin-film transistor gate driver circuitry) may be coupled to gate lines  90 . Display driver circuitry that produces data signals for lines  88  (e.g., a display driver integrated circuit) may be coupled to data lines  88 . 
     Gate driver circuitry, one or more display driver integrated circuits, traces for distributing gate and data signals and other display control signals, and other display control circuitry may be formed in inactive region  46 I of display  14  and display structures  46 . As an example, a display driver integrated circuit may be mounted along the upper segment of inactive region  46 I, whereas gate driver thin-film circuitry may be formed along the left and right segments of inactive region  46 I. During operation of display  14 , display pixels  86  may display images for a user, so the portion of display structures  46  containing display pixels  86  may sometimes be referred to as active display structures or the active area of display  14 . The metal traces and other display control circuit structures in inactive region  46 I do not display any images, so this portion of structures  46  may sometimes be referred to as inactive display structures. 
     Inactive region  46 I may form a border that surrounds some or all of active area  46 A. For example, inactive region  46 I may have a rectangular ring shape of the type shown in  FIG. 6  having opposing upper and lower border segments and left and right border segments. 
     To provide display  14  with a borderless appearance, display  14  may be provided with reflective structures that distribute light from peripheral display pixels  86  near the edge of active area  46 A into a portion of the display overlapping inactive area  46 I. In this way, image content can be displayed over inactive area  46 I, effectively increasing the lateral dimensions of display  14  sufficiently to eliminate inactive area  46 I from view by a user. 
     The reflective structures that are used for distributing edge light in display  14  may be formed from stationary (fixed) mirrors, stationary reflecting prisms, movable reflective structures such as movable mirrors or prisms, or other reflective structures. As an example, a movable mirror may be implemented using microelectromechanical systems (MEMs) mirror structures (sometimes referred to as electromechanical mirrors). If desired, other types of adjustable reflective structures may be used in distributing light near the edge of display  14  to minimize visible borders. Configurations for display  14  in which reflective structures based on electromechanical mirrors are used in distributing light near the edge of display  14  may sometimes be described herein as an example. 
       FIG. 7  is a cross-sectional side view of device  10  in a configuration in which adjustable reflective structures such as electromechanical mirror structures are being used to redistribute light from display pixels near the edge of display  14 . As shown in  FIG. 7 , display  14  may include a display cover layer such as display cover layer  84 . Display cover layer  84  may be mounted in housing  12  of device  10  so as to cover and protect display structures  46 . 
     Control circuitry  29  can control which content is displayed on display pixels  86  of display structures  46  at a given time. Control circuitry  29  may, for example, supply display pixel data and control signals to display pixels  86  using signal paths such as signal path  110 . Synchronously, control circuitry  29  may supply control signals on path  108  to adjust electromechanical mirror structures  100 . Mirror structures  100  may include one or more mirrors arranged around the periphery of display  14 . Mirrors such as illustrative electromechanical mirror  100  of  FIG. 7  may, for example, be formed in linear arrays along the left and right borders of display  14  (and, if desired, along the upper and lower borders of display  14  in addition to along the left and right borders of display  14 ). 
     Electromechanical mirror structures  100  may include reflective structures such as mirror structures or prism structures. Mirror structures  100  may, for example, include a rotatable mirror such as mirror  104 . Mirror  104  may be mounted on an adjustable support such as rotatable actuator  102 . Rotatable actuator  102  may be a yolk that is adjusted by application of a voltage control signal, part of a microelectromechanical systems structure such as a diving board structure on a semiconductor substrate, a solenoid-based structure, a stepper motor structure, a piezoelectric actuator structure, or other controllable positioner. By applying control signals to positioner  102  over path  108  from control circuitry  29 , control circuitry  29  can be used to control the rotation of positioner  102  to control the direction in which mirror  104  reflects light from display structures  46  in real time. 
     Display structures  46  may include active area structures  46 A such as display pixels  86  and inactive area structures  46 I. Structures  46 I do not produce light for displaying content and therefore are associated with an inactive border region around display  14 . Using electromechanical mirror structures  100 , pixel light from some of the display pixels near the edge of display structures  46  (e.g., peripheral display pixels in a rectangular ring shaped peripheral portion of display structures  46 ) can be distributed over inactive region  46 I, thereby providing display  14  with a borderless appearance to a viewer such as viewer  48  who is viewing device  10  in direction  50 . 
     As shown in  FIG. 7 , display pixels  86  may display pixel content such as pixel data P 1 , P 2 , and P 3 . The light from some of the display pixels in display structures  46  such as the light associated with pixel data P 2  and P 3  of display pixels  86  in the example of  FIG. 7  travels vertically to viewer  48  unimpeded, as indicated by light ray lines  112 . Display pixels at the edge of active area  46 A such as the display pixels associated with pixel data P 1 /P 1 ′ of  FIG. 7  produce light that is distributed across pixel locations overlapping inactive border region  46 I. 
     Control circuitry  29  can alter the pixel data that is being presented by the P 1 /P 1 ′ display pixel while synchronously adjusting the position of mirror  104  in adjustable electromechanical mirror structures  100 . Light from display pixel P 1 /P 1 ′ may be reflected onto mirror  104  using reflective structures  106  such as a mirror, prism, or other reflector (e.g., a stationary reflector that is coupled to the display pixel array or other support). By alternating the state of mirror  100  while controlling the pixel data that is displayed by display pixel P 1 /P 1 ′, control circuitry  29  can distribute display light over inactive border region  46 I, so that display  14  appears borderless. 
     In the configuration of  FIG. 7 , for example, when control circuitry  29  is directing display pixel P 1 /P 1 ′ to display pixel data P 1 ′, mirror  100  may be placed in a state in which light from reflector  106  is reflected along path L, whereas when control circuitry  29  is directing display pixel P 1 /P 1 ′ to display pixel data P 1 , mirror  100  may be placed in a state in which light from reflector  106  is reflected along path R. In this way, viewer  49  may observe pixel data P 1 , P 2 , P 3 , . . . in region  114  and may observe pixel data P 1  in region  116 . Region  116  overlaps inactive display structure structures  46 I of display structures  46 , so the presence of pixel data P 1 ′ in region  116  causes viewer  48  to observe a display that is entirely filled with active pixel data and has no inactive border. 
     The graphs of  FIG. 8  illustrate how control circuitry  29  may synchronize the display of pixel content on display pixels  86  with the control of mirror position for electromechanical mirror  100  to produce a borderless display of the type shown in  FIG. 7 . As shown in the upper trace of  FIG. 8 , control circuitry  29  use path  110  to provide display pixels  86  such as peripheral display pixel P 1 /P 1 ′ of  FIG. 7  with pixel data P 1  and P 1 ′ in alternation (e.g., so that pixel data is displayed at twice the data rate of the pixel data in the center of display  14 ). In synchronization with the alternation of pixel data P 1  and P 1 ′, control circuitry  29  adjusts electromechanical mirror structures  100  so that mirror  104  is alternately placed in position L (see ray L of  FIG. 7 ) or position R (see ray R in  FIG. 7 ). Mirror structures  100  will therefore distribute pixel data across an area that is sufficiently large that inactive area  46 I is covered with active pixel data (pixel data P 1 ′ in this example). 
     To ensure that the pixel data that is displayed over inactive region  46 I is sufficiently bright, display structures  46  can be configured so that peripheral display pixels produce more light than center pixels. For example, in the configuration of  FIG. 7 , central display pixels  86  may display pixel data P 2 , P 3 , . . . at an intensity of I/pixel, whereas edge pixel structures  86  may display pixel data P 1 /P 1 ′ at an intensity of 2I/pixel. Because each pixel along the edge is illuminated for half of the time that each pixel in the center is illuminated, the resulting image on display  14  will have uniform pixel intensities. Pixel brightness can be adjusted by locally adjusting the type and density of surface pits and/or bumps used on light guide plate  78  (e.g., so that more backlight is produced under peripheral pixels than central display pixels  86 ). 
     If desired, reflector  106  and electromechanical mirror structures  100  may be configured to reflect pixel data from multiple edge pixels at the same time. As shown in  FIG. 9 , electromechanical mirror structures  100  may, for example, use positioner  102  to adjust the position of mirror  104  so as to distribute light from a strip of display pixels that is N pixels wide. In adjusting mirror structures  100 , positioner  102  controls the rotational orientation of mirror  104  about rotational axis  130  (i.e., mirror  102  is rotated back and forth to distribute pixel light so as to overlap the pixel content with inactive area  46 I, as described in connection with  FIG. 7 ). The value of N may be 2-10, 2-50, 2-100, less than 50, less than 30, less than 20, 1 or more, more than 5, 10 or more, or other suitable value. 
       FIG. 10  shows how display structures  46  may have a bend such as bend  132 . One or more pixels such as pixels  86 ′ in side region  136  may be controlled to produce pixel data in synchronization with the movement of electromechanical mirror structures  100 . This allows electromechanical mirror structures  100  to distribute edge light such as light  134  over the border portion of display  14 , so that viewer  48  perceives display  14  to be borderless. Examples of display structures  46  that may be configured to form a bend include flexible display structures such as organic light-emitting diode display structures formed on a flexible substrate such as a flexible polymer sheet, flexible liquid crystal display structures, flexible electrowetting pixels, an array of flexible electrophoretic display pixels, etc. 
       FIG. 11  is a cross-sectional side view of display  14  in device  10  showing how device  10  may be provided with a fixed reflector to minimize inactive display border width. In the  FIG. 11  example, display structures  46  include a bent peripheral portion such as portion  136  and a planar central region  140 . Bent portion  136  may contain active display pixels  86 ′ that produce display light  134 . Reflector  138  may be a mirror or prism that is configured to reflect light  134  from pixels  86 ′ upwards into active peripheral edge region  116 . Pixels  86  in central portion  140  lie in a plane parallel to display cover layer  84  and produce light  112  that is visible in active central display region  114 . When using reflector  138  to reflect pixel light  134  upwards into edge region  116 , edge region  116  will be filled with active image content in addition to central region  114 , thereby increasing the apparent size of display  14  and eliminating or at least reducing visible inactive border portions of display  14  that would otherwise be visible to a viewer such as viewer  48  viewing display  14  in direction  50 . 
     In the illustrative configuration of  FIG. 7 , display pixel light from edge pixels such as edge pixel P 1 /P 1 ′ was distributed using a 1:2 distribution ratio (i.e., light from each active edge pixel in structures  46  was fanned out to cover two corresponding pixels in region  116 ). If desired, other distribution ratios may be used in distributing edge light in display  14 . As an example, a fan-out ratio of 1:3 or 1:4 may be used. 
     Consider, as an example, the display configuration of  FIGS. 12, 13, and 14 , which uses a 1:3 edge light distribution ratio. As shown in  FIG. 12 , peripheral pixel  86 ″ may produce light  134  that reflects off of electromechanical mirror structures  100 . Mirror structures  100  may be adjusted by control circuitry  29  to reflect light  134  into edge pixel location  116 - 1  (as shown in  FIG. 12 ), edge pixel location  116 - 2  (as shown in  FIG. 13 ), or edge pixel location  116 - 3  (as shown in  FIG. 14 ). 
     When reflecting light  134  into location  116 - 1 , display pixel  86 ″ may be controlled by control circuitry  29  to display pixel data P 1 ″, as shown in  FIG. 12 . When reflecting light  134  into location  116 - 2 , display pixel  86 ″ may be controlled by control circuitry  29  to display pixel data P 1 ′, as shown in  FIG. 13 .  FIG. 14  shows how control circuitry  29  may direct display pixel  86 ″ to display pixel data P 1  when electromechanical mirror structures  100  are adjusted to reflect light  134  into location  116 - 3 . 
     To compensate for the light intensity reduction that is experienced by pixels  116 - 1 ,  116 - 2 , and  116 - 3  (each of which receives only one third of light  134  from pixel  86 ″ when averaged over time), pixel  86 ″ can be configured to emit light  134  with an intensity that is proportionally greater than the intensity with which light  112  is emitted by pixels  86 . In particular, pixels such as pixel  86 ″ from which light is distributed across edge portion  116  in display  14  may be configured to be three times brighter than pixels such as pixels  86 . In displays with different fan-out ratios, the brightness of edge pixels such as pixel  86 ″ can be adjusted accordingly. Light from multiple edge pixels such as pixel may be redistributed in parallel using a mirror configuration of the type shown in  FIG. 9 . 
     Reflective structures such as reflector  106  and/or reflector  104  in electromechanical mirror  100  may be provided with non-planar surfaces. As shown in  FIG. 15 , for example, reflector  106  may have non-planar surface shapes such as curved surface shapes  140  and/or reflector  104  may have non-planar surface shapes such as curved surface shapes  142 . Lenses and other optical structures may also be interposed in the path of light  134  to help direct light  134  along the edge of display  14 . 
     If desired, electromechanical mirror structures  100  may be used to direct light into an image sensor. This type of arrangement is shown in  FIG. 16 . As shown in  FIG. 16 , imaging system  150  may have optical structures  151  such as one or more lenses for gathering and focusing image light and a digital image sensor such as digital image sensor  154  that detects the focused image light. Image sensor  154  may be formed from a semiconductor substrate such as a silicon substrate (i.e., image sensor  154  may be a silicon digital imaging integrated circuit). Image sensor  154  may have central image sensor pixels such as pixels  158  that directly receive image light from an external object such as light  164 . Image sensor  154  may also include peripheral image sensor pixels such as pixel  156  of  FIG. 16  that receive incoming light from an external object that has reflected off of reflectors such as mirror  104  and mirror  106 . 
     Image sensor  154  may have an inactive border region such as border region  160 . Border region  160  may have a shape of a rectangular ring that runs around the peripheral edge of image sensor  154 . Electromechanical mirror structures  100  may be adjusted in real time by control circuitry  29  via control path  166  while control circuitry  29  is provided with digital image data from image sensor  154  via digital data path  168 . Mirror structures  100  may run along one or more, two or more, three or more, or four edges of image sensor  154 . 
     During the acquisition of digital data using sensor  154 , control circuitry  166  can adjust the position of mirror  104  in electromechanical mirror structures  100 . Edge pixels such as edge pixel  156  may gather light such as light  152  when mirror  104  is in a first position and may gather light such as light  162  from another direction when mirror  104  is in a second position that is different from the first position. Because mirror structures  100  overlap inactive image sensor structures  160 , the use of mirror structures  100  to deflect light into pixel  156  helps to expand the effective size of digital image sensor  154  (e.g., to effectively produce a digital image sensor that has a minimal inactive border region or has no inactive border region). If desired, mirror  100  may be used to deflect light for multiple image pixels in parallel. The configuration of  FIG. 16  in which mirror  100  is being used to reflect light onto edge pixel structures with a one-pixel width is merely illustrative. 
     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: 20120928
Publication Date: 20160510
Grant Date: 20160510
Priority Date: 20120928
Inventors: YANG TSENG-MAU
MEMERING DALE N.
PREST CHRISTOPHER D.
Assignee: APPLE INC
CPC Classifications: [{"code": "G02B7/1805", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B26/0841", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B26/0841", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B26/0841", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/1805", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B7/1805", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 50384818