PATENT DOCUMENT

Publication Number: US-9349329-B2
Application Number: US-201313927521-A
Country: US
Kind Code: B2

Title: Displays with light leakage reduction structures

Abstract:
An electronic device is provided with a display such as a liquid crystal display. The display includes a display module having an array of display pixels and a backlight unit configured to provide backlight to the array of display pixels. The array of display pixels includes display pixels in a central region surrounded by display pixels in a border region. To minimize light leakage from the display, display control circuitry drives the display pixels in the central region according to a first gray level mapping function and drives the display pixels in the border region according to a second gray level mapping function. Light leakage reduction structures may be used to reduce the intensity of backlight received by display pixels in the border region relative to the intensity of backlight received by display pixels in the central region.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a display having an array of display pixels, wherein the array of display pixels comprises display pixels in a rectangular central region and display pixels in a border region surrounding the central region; 
 a backlight unit configured to provide backlight to the array of display pixels; 
 light leakage reduction structures configured to reduce an intensity of backlight received by the display pixels in the border region relative to an intensity of backlight received by the display pixels in the central region; and 
 display control circuitry configured to drive the display pixels in the central region according to a gray level mapping function and to drive the display pixels in the border region according to a modified gray level mapping function, wherein the gray level mapping function determines first pixel transmissivity levels based on digital input gray levels, and wherein the modified gray level mapping function determines second pixel transmissivity levels that are different from the first pixel transmissivity levels based on the digital input gray levels. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the light leakage reduction structures comprise a shutter module interposed between the backlight unit and the array of display pixels. 
     
     
       3. The electronic device defined in  claim 2  wherein the shutter module comprises a polymer-dispersed liquid crystal layer. 
     
     
       4. The electronic device defined in  claim 2  wherein gray level mapping function and the modified gray level mapping function are the same for digital input gray levels above a threshold gray level. 
     
     
       5. The electronic device defined in  claim 1  wherein the backlight unit comprises a light guide plate and wherein the light leakage reduction structures comprise light-scattering features in the light guide plate having a gradient density along a surface of the light guide plate. 
     
     
       6. The electronic device defined in  claim 5  wherein the density of the light-scattering features under the display pixels in the border region is less than the density of light-scattering features under the display pixels in the central region. 
     
     
       7. The electronic device defined in  claim 1  wherein the first pixel transmissivity levels are the same as the second pixel transmissivity levels for digital input gray levels above a threshold gray level. 
     
     
       8. The electronic device defined in  claim 7 , wherein the first pixel transmissivity levels are different from the second pixel transmissivity levels for digital input gray levels below the threshold gray level. 
     
     
       9. A method for displaying a gray level on a display pixel in a display having an array of display pixels, wherein the array of display pixels comprises display pixels in a central region of the display and display pixels in a border region of the display that surrounds the central region, the method comprising:
 with a backlight unit, providing backlight to the array of display pixels, wherein the intensity of backlight received by the display pixels in the border region of the display is lower than the intensity of backlight received by the display pixels in the central region of the display; 
 with display control circuitry, determining whether the display pixel is in the border region of the display; 
 in response to determining that the display pixel is not in the border region of the display, driving the display pixel according to a gray level mapping function; and 
 in response to determining that the display pixel is in the border region of the display, driving the display pixel according to a modified gray level mapping function, wherein the gray level mapping function and the modified gray level mapping function map digital input gray levels to pixel transmissivity levels, and wherein the gray level mapping function and the modified gray level mapping function map a first digital input level to different pixel transmissivity levels. 
 
     
     
       10. The method defined in  claim 9  wherein the backlight unit comprises a light guide plate having light-scattering features, wherein the light-scattering features are configured such that the display pixels in the border region receive a reduced backlight intensity compared to the display pixels in the central region, and wherein driving the display pixel according to the modified gray level mapping function comprises compensating for the reduced backlight intensity. 
     
     
       11. The method defined in  claim 9  further comprising:
 in response to determining that the display pixel is in the border region of the display, activating a shutter module interposed between the display pixel and the backlight unit to block a portion of the backlight so that the intensity of backlight received by the display pixels in the border region of the display is lower than the intensity of backlight received by display pixels in the central region of the display. 
 
     
     
       12. The method defined in  claim 11  wherein the shutter module comprises a polymer-dispersed liquid crystal layer and wherein activating the shutter module comprises adjusting an electric field across the polymer-dispersed liquid crystal layer. 
     
     
       13. The method defined in  claim 9 , wherein the gray level mapping function maps the first digital input level to a first pixel transmissivity level, and wherein the modified gray level mapping function maps the first digital input level to a second pixel transmissivity level that is different than the first pixel transmissivity level. 
     
     
       14. The method defined in  claim 9 , wherein the display pixels in the border region of the display and the display pixels in the central region of the display are matrix addressable. 
     
     
       15. A method for displaying a gray level on a display pixel in a display having an array of display pixels, wherein the array of display pixels comprises display pixels in a central region of the display and display pixels in a border region of the display that surrounds the central region, the method comprising:
 with the display control circuitry, determining whether the display pixel is in the border region of the display; 
 in response to determining that the display pixel is not in the border region of the display, driving the display pixel according to a gray level mapping function, wherein the gray level mapping function maps digital input gray levels to first pixel transmissivity levels; and 
 in response to determining that the display pixel is in the border region of the display:
 with display control circuitry, determining whether a digital input gray level is below a threshold gray level; 
 in response to determining that the digital input gray level is below the threshold gray level, activating a shutter module to reduce an intensity of backlight received by the display pixel; and 
 with the display control circuitry, driving the display pixel according to a modified gray level mapping function, wherein the modified gray level mapping function maps the digital input gray levels to second pixel transmissivity levels that are different than the first pixel transmissivity levels. 
 
 
     
     
       16. The method defined in  claim 15  further comprising:
 with a backlight unit, providing the backlight to the array of display pixels, wherein the shutter module is interposed between the backlight unit and the array of display pixels. 
 
     
     
       17. The method defined in  claim 16  wherein driving the display pixel according to a modified gray level mapping function comprises compensating for the reduced intensity of backlight received by the display pixel. 
     
     
       18. The method defined in  claim 15  wherein the shutter module comprises a polymer-dispersed liquid crystal layer and wherein activating the shutter module comprises adjusting an electric field across the polymer-dispersed liquid crystal layer so that the polymer-dispersed liquid crystal layer is only partially transmissive. 
     
     
       19. The method defined in  claim 15  wherein the shutter module comprises a polymer-dispersed liquid crystal layer and wherein deactivating the shutter module comprises adjusting an electric field across the polymer-dispersed liquid crystal layer so that the polymer-dispersed liquid crystal layer is fully transmissive.

Description:
BACKGROUND 
     This relates generally to displays, and, more particularly, to displays such as liquid crystal displays. 
     Displays are widely used in electronic devices to display images. Displays such as liquid crystal displays display images by controlling liquid crystal material in the display using electrodes associated with an array of image pixels. In a typical liquid crystal display, the liquid crystal material is formed between a glass layer with an array of thin-film transistor circuits and a glass layer with an array of color filter elements. 
     Portions of a liquid crystal display often experience stresses due to mounting structures that are attached to the display or due to internal display structures. During operation of a conventional liquid crystal display, the liquid crystal material is sometimes arranged so that light is blocked from escaping from the display. However, in a portion of the display that is under stress, a fraction of that light can sometimes escape from that portion of the display or from a nearby portion of the display. This type of light leakage from a display under stress can create difficulties in, for example, displaying images with dark portions. 
     It would therefore be desirable to be able to provide improved displays such as displays that exhibit minimized light leakage under stress. 
     SUMMARY 
     An electronic device is provided with a display such as a liquid crystal display mounted in an electronic device housing. The display includes a display module having an array of display pixels. The array of display pixels includes display pixels in a central region of the display and display pixels in a border region of the display. 
     A backlight unit is used to provide backlight illumination to the display module. The backlight unit may include a light guide plate and a light source that emits light into an edge of the light guide plate. The light guide plate is used to distribute the light uniformly across the display. 
     The display includes display control circuitry and light leakage reduction structures. The display control circuitry is configured to drive each display pixel based on whether or not the display pixel is in the central region or the border region of the display. The display control circuitry may also be configured to drive each display pixel based on whether or not an input gray value for the display pixel is above or below a threshold gray value. 
     Display pixels in the central region are driven according to a first gray level mapping curve. Display pixels in the border region are driven according to a second gray level mapping curve that is different from the first gray level mapping curve. The first and second gray level mapping curves are used to map digital input gray levels to pixel transmissivity levels. 
     To reduce light leakage from the display, the second gray level mapping curve maps input gray levels below a light leakage threshold level to higher pixel transmissivity levels than the first gray level mapping curve. Higher transmissivity levels may in turn lead to minimized light leakage. 
     To ensure that display pixels in the border region display light having a desired intensity, light leakage reduction structures are configured to reduce the intensity of backlight received by the display pixels in the border region relative to the intensity of backlight received by display pixels in the central region. The increase in pixel transmissivity and the reduction in backlight intensity are coordinated such that the display pixel displays light at the desired intensity. 
     The light leakage reduction structures may be switchable or non-switchable. In one suitable embodiment, the light leakage reduction structures are light-scattering features in the light guide plate. The light-scattering features have a gradient density such that less light is scattered upwards towards pixels in the border region than towards pixels in the central region. 
     In another suitable embodiment, the light leakage reduction structures include a shutter module interposed between the backlight unit and the array of display pixels. The shutter module includes one or more local dimming elements formed from a polymer-dispersed liquid crystal layer. The local dimming element may be activated by adjusting an electric field across the polymer-dispersed liquid crystal layer such that the polymer-dispersed liquid crystal layer is only partially transmissive. The local dimming element may be deactivated by adjusting the electric field across the polymer-dispersed liquid crystal layer such that the polymer-dispersed liquid crystal layer is fully transmissive. 
     Further features, their 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 display structures in accordance with an embodiment. 
         FIG. 2  is a perspective view of an illustrative electronic device such as a handheld electronic device with display structures in accordance with an embodiment. 
         FIG. 3  is a perspective view of an illustrative electronic device such as a tablet computer with display structures in accordance with an embodiment. 
         FIG. 4  is a perspective view of an illustrative electronic device such as a computer display with display structures in accordance with an embodiment. 
         FIG. 5  is a schematic diagram of an illustrative electronic device of the type shown in  FIGS. 1, 2, 3, and 4  in accordance with an embodiment. 
         FIG. 6  a cross-sectional side view of an illustrative display of the type that may be used in devices of the types shown in  FIGS. 1, 2, 3, and 4  in accordance with an embodiment. 
         FIG. 7  is a graph showing how light leakage in a conventional display varies as a function of input gray level. 
         FIG. 8  is a graph of luminance as a function of input gray value showing how a display may have a light leakage threshold value in accordance with an embodiment. 
         FIG. 9  is a top view of display  14  showing how a pixel array may include display pixels in a central region surrounded by display pixels in a border region in accordance with an embodiment. 
         FIG. 10  is a graph showing how display pixels in a border region of a display may be driven according to a different gray level mapping function than display pixels in a central region of the display in accordance with an embodiment. 
         FIG. 11  is a cross-sectional side view of a portion of a display showing how light-scattering features in a light guide plate may be configured to scatter less light towards display pixels in a border region of the display than towards display pixels in a central region of the display in accordance with an embodiment. 
         FIG. 12  is a cross-sectional side view of a portion of a display showing how light-scattering features in a light guide plate may have a gradient density along a surface of the light guide plate in accordance with an embodiment. 
         FIG. 13  is a cross-sectional side view of a portion of a display showing how a shutter module having one or more local dimming elements may be interposed between an array of display pixels and a backlight module in accordance with an embodiment of the present invention. 
         FIG. 14  is a cross-sectional side view of a local dimming element formed from a polymer-dispersed liquid crystal layer in accordance with an embodiment. 
         FIG. 15  is a flow chart of illustrative steps involved in operating a display having static light leakage reduction structures in accordance with an embodiment. 
         FIG. 16  is a flow chart of illustrative steps involved in operating a display having dynamic light leakage reduction structures in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Displays are widely used in electronic devices. For example, displays may be used in computer monitors, laptop computers, media players, cellular telephones, televisions, and other equipment. Displays may be based on plasma technology, organic-light-emitting-diode technology, liquid crystal structures, or other suitable display structures. 
     Liquid crystal displays are popular because they can exhibit low power consumption and good image quality. Liquid crystal display structures are sometimes described herein as an example. In order to minimize light leakage from the display when some or all of the display is under stress (e.g., when some or all of the display is experiencing an internal or external pressure or force) a liquid crystal display may be provided with one or more light leakage reduction structures. The light leakage reduction structures may be used in combination with display control circuitry to reduce light leakage from the display. 
     Illustrative electronic devices that have displays with light leakage reduction structures and display control circuitry that may be used to minimize light leakage from the display are shown in  FIGS. 1, 2, 3, and 4 . 
     Electronic device  10  of  FIG. 1  has the shape of a laptop computer and has upper housing  12 A and lower housing  12 B with components such as keyboard  16  and touchpad  18 . Device  10  has hinge structures  20  to allow upper housing  12 A to rotate in directions  22  about rotational axis  24  relative to lower housing  12 B. Display  14  is mounted in upper housing  12 A. Upper housing  12 A, which may sometimes referred to as a display housing or lid, is placed in a closed position by rotating upper housing  12 A towards lower housing  12 B about rotational axis  24 . 
       FIG. 2  shows an illustrative configuration for electronic device  10  based on 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  has opposing front and rear surfaces. Display  14  is mounted on a front face of housing  12 . Display  14  may have an exterior layer that includes openings for components such as button  26  and speaker port  28 . 
     In the example of  FIG. 3 , electronic device  10  is a tablet computer. In electronic device  10  of  FIG. 3 , housing  12  has opposing planar front and rear surfaces. Display  14  is mounted on the front surface of housing  12 . As shown in  FIG. 3 , display  14  has an external layer with an opening to accommodate button  26 . 
       FIG. 4  shows an illustrative configuration for electronic device  10  in which device  10  is a computer display or a computer that has been integrated into a computer display. With this type of arrangement, housing  12  for device  10  is mounted on a support structure such as stand  27 . Display  14  is mounted on a front face of housing  12 . 
     The illustrative configurations for device  10  that are shown in  FIGS. 1, 2, 3, and 4  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, is 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. 
     Display  14  for device  10  includes display pixels formed from liquid crystal display (LCD) components or other suitable image pixel structures. 
     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 . The outermost display layer may be formed from a transparent glass sheet, a clear plastic layer, or other transparent member. 
     A schematic diagram of electronic device  10  is shown in  FIG. 5 . As shown in  FIG. 5 , electronic device  10  includes a display such as display  14 . Display  14  includes display module  46  having an array of display pixels  46 P, light leakage reduction structures  62 , and display control circuitry  30  for operating display module  46  and, in some arrangements, for operating light leakage reduction structures  62 . 
     Display pixels  46 P may be formed from reflective components, liquid crystal display (LCD) components, organic light-emitting diode (OLED) components, or other suitable display pixel structures. Arrangements in which display pixels  46 P are liquid crystal display pixels are sometimes described herein as an illustrative example. To provide display  14  with the ability to display color images, display pixels  46 P may include color filter elements. Each color filter element may be used to impart color to the light associated with a respective display pixel  46 P in pixel array of display  14 . 
     Light leakage reduction structures  62  and display control circuitry  30  are used to help control the amount of light that is emitted by display  14 . For example, display control circuitry  30  may be used to increase the voltage applied to pixels in light leakage regions (thereby increasing the transmissivity of those pixels), while, at the same time, light leakage reduction structures may be used to reduce the amount of backlight that reaches those pixels. The reduced backlight intensity and corresponding shift in pixel voltage may help suppress or eliminate light leakage from display  14 . 
     Light leakage reduction structures  62  may be switchable (i.e., dynamic) or non-switchable (i.e., static). In configurations where structures  62  are dynamic, structures  62  may include an array, ring, or other arrangement of local dimming elements. Each local dimming element may be used to control the amount of backlight that reaches overlapping display pixels  46 P from a backlight unit. For example, when it is desired to display black in a selected region of display  14 , light leakage reduction structures  62  that overlap that region are manipulated to block light from reaching display pixels  46 P in the selected region. 
     In configurations where structures  62  are static, structures  62  may be configured to reduce the amount of backlight that reaches display pixels  46 P in one or more regions of display  14 . 
     Display control circuitry  30  may include a graphics controller (sometimes referred to as a video card or video adapter) that may be used to provide video data and control signals to display  14 . Video data may include text, graphics, images, moving video content, or other content to be presented on display  14 . 
     Display control circuitry  30  may also include display driver circuitry. Display driver circuitry in circuitry  30  may be implemented using one or more integrated circuits (ICs) and is sometimes be referred to as a driver IC, display driver integrated circuit, or display driver. If desired, the display driver integrated circuit may be mounted on an edge of a thin-film-transistor substrate layer in display  14  (as an example). Display control circuitry  30  may include timing controller (TCON) circuitry such as a TCON integrated circuit. The timing controller may be used to supply pixel signals to display pixels  46 P. In configurations where light leakage reduction structures  62  are switchable, the timing controller used to supply pixel signals to display pixels  46 P may also be used to supply signals to light leakage reduction structures  62 . If desired, a separate timing controller may supply signals to light leakage reduction structures. 
     Display control circuitry  30  may supply pixel signals to each display pixel  46 P based on whether or not that pixel is in a light leakage region and/or based on whether or not the input pixel value is within a light leakage range of pixel values. For example, display control circuitry  30  may use a lookup table to adjust the transmissivity of a pixel when the input pixel value is within a light leakage range of pixel values and/or when a pixel is in a light leakage region of the display. 
     Display control circuitry  30  may be coupled to additional circuitry in device  10  such as storage and processing circuitry  33 . Storage and processing circuitry  33  in device  10  may include microprocessors, microcontrollers, digital signal processor integrated circuits, application-specific integrated circuits, and other processing circuitry. Volatile and non-volatile memory circuits such as random-access memory, read-only memory, hard disk drive storage, solid state drives, and other storage circuitry may also be included in circuitry  33 . Display calibration information may be stored using circuitry  33  or may be stored using display control circuitry  30  or other circuitry associated with display  14 . 
     Circuitry  33  may use wireless communications circuitry  35  and/or input-output devices  37  to obtain user input and to provide output to a user. Input-output devices  37  may include speakers, microphones, sensors, buttons, keyboards, displays, touch sensors, and other components for receiving input and supplying output. Wireless communications circuitry  35  may include wireless local area network transceiver circuitry, cellular telephone network transceiver circuitry, and other components for wireless communication. 
     A cross-sectional side view of an illustrative configuration for display  14  of device  10  (e.g., for display  14  of the devices of  FIG. 1 ,  FIG. 2 ,  FIG. 3 ,  FIG. 4  or other suitable electronic devices) is shown in  FIG. 6 . As shown in  FIG. 6 , display  14  includes 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. 6 ) 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  illuminates images on display layers  46  that are being viewed by viewer  48  in direction  50 . 
     Display layers  46  may be mounted in chassis structures such as a plastic chassis structure and/or a metal chassis structure to form a display module for mounting in housing  12  or display layers  46  may be mounted directly in housing  12  (e.g., by stacking display layers  46  into a recessed portion in housing  12 ). Display layers  46  form a liquid crystal display or may be used in forming displays of other types. 
     In a configuration in which display layers  46  are used in forming a liquid crystal display, display layers  46  include a liquid crystal layer such as liquid crystal layer  52 . Liquid crystal layer  52  is sandwiched between display layers such as display layers  56  and  58 . Layers  56  and  58  are interposed between lower polarizer layer  60  and upper polarizer layer  54 . Display layers  46  are sometimes collectively referred to herein as “display module”  46 . 
     Layers  56  and  58  are formed from transparent substrate layers such as clear layers of glass or plastic. Layers  56  and  58  are layers such as a color filter layer (e.g., a color filter layer substrate such as a layer of glass having a layer of color filter elements such as red, green, and blue color filter elements arranged in an array) and/or a thin-film transistor layer (e.g., a thin-film transistor substrate such as a glass layer coated with a layer of thin-film transistor circuitry). Conductive traces, color filter elements, transistors, and other circuits and structures are formed on the substrates of layers  56  and  58  (e.g., to form a color filter layer and/or a thin-film transistor layer). Touch sensor electrodes may also be incorporated into layers such as layers  56  and  58  and/or touch sensor electrodes may be formed on other substrates. 
     With one illustrative configuration, layer  58  is 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  is 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. 
     Display module  46  is illuminated with backlight  44  provided by backlight structures  42 . In the example of  FIG. 6 , backlight structures  42  include a light guide plate such as light guide plate  78 . Light guide plate  78  is 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  generates light  74 . Light source  72  may be, for example, an array of light-emitting diodes. 
     Light  74  from one or more light sources such as light source  72  is coupled into one or more corresponding edge surfaces such as edge surface  76  of light guide plate  78  and is distributed in dimensions X and Y throughout light guide plate  78  due to the principal of total internal reflection. Light guide plate  78  includes light-scattering features such as pits or bumps. The light-scattering features are 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  serves as backlight  44  for display  14 . Light  74  that scatters downwards is reflected back in the upwards direction by reflector  80 . Reflector  80  is formed from a reflective material such as a layer of white plastic or other shiny materials. The use of a reflector in backlight  42  is, however, merely illustrative and may not be needed in some configurations. 
     The configuration of  FIG. 6  in which backlight structures  42  form part of an edge-lit display is merely illustrative. If desired, other suitable types of backlights may be used in display  14 . For example, backlight structures  42  may include an array (e.g., a rectangular array) of light-emitting diodes or organic light-emitting diodes formed behind display module  46  or may include other light sources such as a cold-cathode florescent lamp. Arrangements in which display  14  is an edge-lit display (e.g., in which a light source emits light into the edge of a light guide plate which in turn distributes the light across the display panel) are sometimes described herein as an example. 
     To enhance backlight performance for backlight structures  42 , backlight structures  42  optionally include optical films  70 . Optical films  70  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  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. 6 , optical films  70  and reflector  80  preferably have a matching rectangular footprint. The configuration of  FIG. 6  in which optical films  70  are located directly above light guide plate  78  is merely illustrative. If desired, optical films  70  may be located elsewhere in display  14 . 
     In some configurations, light leakage reduction structures  62  are integrated into backlight structures  42 . For example, as shown in  FIG. 6 , light leakage reduction structures  62 A may be integrated into light guide plate  78 . Structures  62 A may, for example, be light-scattering features (e.g., bumps, pits, roughened surfaces, or other suitable light-scattering features) in light guide plate  78 . Light leakage reduction structures  62 A may be configured to reduce the amount of light that is scattered upwards towards display pixels in light leakage regions (e.g., display pixels in a border region of the display) relative to the amount of light that is scattered upwards towards display pixels that are not in light leakage regions (e.g., display pixels in a central region of the display). 
     For example, edge pixels that tend to exhibit greater light leakage than center pixels may receive a reduced amount of backlight  44  from light guide plate  78  compared to the amount of backlight  44  received by center pixels. This may be achieved by, for example, configuring light-scattering features  62 A (e.g., configuring the density, size, shape, location, and/or type of light-scattering features  62 A) in light guide plate  78  to scatter more light upwards (in direction Z) from the central portion of the upper surface of light guide plate  78  than from the peripheral portion of the upper surface of light guide plate  78 . 
     In other configurations, light leakage reduction structures  62  are formed from a shutter module that controls the transmission of backlight  44  from backlight structures  42 . For example, as shown in  FIG. 6 , light leakage reduction structures  62 B (sometimes referred to as shutter module  62 B) may be interposed between backlight structures  42  and display module  46 . Shutter module  62 B may include one or more local dimming elements. Each local dimming element may be configured to control the amount of backlight  44  that reaches a given region of display  14 . 
     Local dimming elements in shutter module  62 B can have different shapes and sizes or local dimming elements can all have the same shape and size. In one suitable embodiment, local dimming elements in shutter module  62 B are arranged in an array of rows and columns. In another suitable embodiment, shutter module  62 B includes a single dimming element that forms a rectangular ring that is aligned with the display pixels in the border region of the display. Local dimming elements in shutter module  62 B can have the same resolution as display pixels  46 P ( FIG. 5 ) in display module  46  or local dimming elements can have a resolution that is greater or less than the resolution of display pixels  46 P in display module  46 . 
     Shutter module  62 B may be formed from liquid crystal structures, polymer-dispersed liquid crystal structures, reflective display structures, electrowetting display structures, electrophoretic display structures, microelectromechanical systems-based shutter elements, photovoltaic materials, and/or other suitable light-controlling structures. Each local dimming element in shutter module  62 B is configured to control light transmission independently of the other local dimming elements in shutter module  62 B. Local dimming elements can be controlled using data line signals on data lines and gate line signals on gate lines. 
     Shutter module  62 B may be configured to reduce the amount of backlight  44  that reaches display pixels  46 P in light leakage regions of display  14 . For example, edge pixels that are more prone to exhibit light leakage than center pixels may receive a reduced amount of backlight  44  from light guide plate  78  compared to the amount of backlight  44  received by center pixels. This may be achieved by, for example, using shutter module  62 B to block some or all of backlight  44  from reaching edge display pixels, while allowing all of backlight  44  to reach center pixels. 
     Shutter module  62 B may be assembled with other display structures in display  14  in any suitable fashion. In one suitable embodiment, shutter module  62 B is laminated to display module  46  using an adhesive such as optically clear adhesive. In another suitable embodiment, an air gap may separate display module  46  from shutter module  62 B. If desired, display module  46  and shutter module  62 B may be manufactured as a single panel. 
     During operation of display  14 , control circuitry in device  10  (e.g., circuitry  33  of  FIG. 5 ) is used to generate information to be displayed on display  14  (e.g., display data). The information to be displayed is conveyed from the control circuitry to display control circuitry  30  (e.g., a display driver integrated circuit that is mounted on a ledge of thin-film transistor layer  58  or elsewhere in device  10 ). If desired, a flexible printed circuit cable can be used in routing signals between the control circuitry and thin-film-transistor layer  58 . 
     If desired, a single display control circuit (e.g., a timing controller (ICON) integrated circuit in circuitry  30  of  FIG. 5 ) may be used to control both display module  46  and shutter module  62 B. With this type of configuration, the timing controller supplies data line and gate line signals to both display module  46  and shutter structures  62 B. The use of a single timing controller integrated circuit to control both display module  46  and shutter module  62 B is merely illustrative. If desired, a first timing controller integrated circuit can be used to control display module  46  and a second timing controller integrated circuit can be used to control shutter module  62 B. 
       FIG. 7  is a graph illustrating how ΔL/L in a conventional display varies as a function of the input gray level, where ΔL corresponds to luminance error (sometimes referred to as light leakage), and L corresponds to luminance. As the input gray level increases, the measured luminance increases and the error in luminance decreases. Beyond a threshold luminance, the error in luminance becomes insignificant (e.g., light leakage becomes unnoticeable to a viewer). In other words, light leakage in conventional displays tends to be observable for dark, low-luminance colors such as black and dark grays (e.g., input gray levels below 60). The input gray level at which luminance error becomes insignificant is sometimes referred to herein as the light leakage threshold gray level (LL). 
     Light leakage may therefore be minimized by increasing pixel transmissivity for input gray levels below the light leakage threshold level. Increasing pixel transmissivity for low gray levels my reduce or eliminate light leakage. For example, as shown in  FIG. 8 , an input gray level for a pixel such as input gray level G may fall below light leakage threshold LL. In order to minimize light leakage from the pixel while still displaying light with the desired luminance L1, the transmissivity of the pixel for the input gray level may be increased while, at the same time, light leakage reduction structures  62  ( FIG. 5 ) may decrease the intensity of backlight received by the pixel by a corresponding amount. Pixels that receive input gray levels above the light leakage threshold LL may exhibit minimal light leakage. 
     If desired, the light leakage threshold LL may be determined on a per-device basis. For example, display performance information such as luminance information and luminance error information may be gathered from display  14  during manufacturing and may be used to determine the light leakage threshold gray value LL for display  14 . The light leakage threshold gray value may, for example, be a value between 40 and 80, between 50 and 70, between 55 and 65, less than 60, greater than 60, etc. 
     It should be appreciated that  FIGS. 7 and 8  are examples in which each color channel has eight bits dedicated to it. Alternative embodiments may employ greater or fewer bits per color channel. For example, each color may, if desired, have six bits dedicated to it. With this type of configuration, gray levels may range from 0 to 64. Arrangements in which each color channel has eight bits dedicated to it are sometimes described herein as an example. 
     Some regions of a display may be more prone to light leakage than other regions of a display. For example, stress-induced birefringence may cause light leakage at edges and corners of a display, whereas the central portion of a display may exhibit little to no light leakage. It may therefore be desirable to adjust the gray level mapping function used to drive pixels in light leakage regions where light leakage tends to be an issue. The gray level mapping function used to drive pixels that are located in regions of the display that do not tend to exhibit light leakage need not be adjusted. 
       FIG. 9  is a top view of display  14  showing how pixels  46 P may be located in region  14 A of display  14  and how pixels  46 P′ may be located in region  14 B of display  14 . Region  14 A may be a region of display  14  that is not prone to light leakage. Region  14 B may be a region of display  14  that, if care is not taken, may be prone to light leakage when input gray levels are below the light leakage threshold and when the gray level mapping function is not adjusted. Pixels  46 P in region  14 A may therefore be driven according to a first gray level mapping function, whereas pixels  46 P′ in region  14 B may be driven according to a second (modified) gray level mapping function that is different from the first gray level mapping function. As used herein, “gray level mapping function” refers to a function that maps digital input gray levels to pixel transmissivity levels. 
     The phrase “light leakage region” may be used herein to describe a region of display  14  that can, if care is not taken, exhibit light leakage when pixels in that region receive input gray levels below the light leakage threshold gray level LL and when the gray level mapping function is not adjusted to reduce light leakage. In the illustrative example of  FIG. 9 , light leakage region  14 B forms a rectangular ring around central portion  14 A of display  14 . Region  14 B may have a width W between 1 cm and 10 cm, between 2 cm and 8 cm, between 3 cm and 5 cm, less than 10 cm, greater than 10 cm, etc. 
     Light leakage in region  14 B may be minimized by increasing the transmissivity of pixels  46 P′ for input gray levels that are less than the light leakage threshold LL. To achieve the desired gray level output from pixels  46 P′, the increase in transmissivity of pixels  46 P′ may be accompanied by a corresponding decrease in backlight intensity received by pixels  46 P′. The intensity of backlight received by pixels  46 P′ may be reduced using light leakage reduction structures  62  (e.g., light leakage reduction structures  62 A or light leakage reduction structures  62 B of  FIG. 6 ). Pixels  46 P′ in region  14 B may overlap light leakage reduction structures  62  that reduce the intensity of backlight received by pixels  46 P′. 
     The example of  FIG. 9  in which light leakage region  14 B is a rectangular ring that surrounds central region  14 A is merely illustrative. In general, any suitable region of pixels in display  14  may be driven at increased voltages when input gray levels are below a gray level threshold LL while receiving reduced backlight intensity. For example, light leakage region  14 B may include one or more top rows and one or more bottom rows of pixels; may include one or more left columns and one or more right columns of pixels; may include pixels in a central portion of the display; may include the entire array of pixels; or may include any other suitable region(s) of pixels. Arrangements in which region  14 A is a rectangular central region of display  14  and in which region  14 B forms a border that surrounds central region  14 A are sometimes described herein as an example. 
     If desired, light leakage regions of display  14  may be determined during manufacturing on a per-device basis. In one suitable embodiment, a camera may be used to take images of display  14  and to determine the luminance error distribution across the panel. The luminance error information may be used to determine which regions are susceptible to light leakage (such as region  14 B of  FIG. 9 ). Display  14  (e.g., display control circuitry  30  and/or light leakage reduction structures  62 ) may then be configured such that pixels  46 P′ in the determined light leakage regions receive reduced backlight intensity and corresponding shifts in pixel transmissivity. This is, however, merely illustrative. If desired, light leakage regions  14 B may be determined for device  10  without gathering luminance error information from display  14 . 
     Display control circuitry  30  may therefore use a modified gray level mapping function for controlling pixels  46 P′ in border region  14 B relative to the gray level mapping function used to control pixels  46 P in central region  14 A. A graph showing illustrative gray level mapping functions that may be used in respectively controlling pixels  46 P′ in border region  14 B and pixels  46 P in central region  14 A is shown in  FIG. 10 . 
     Gray level mapping function  15 A of  FIG. 10  is used to determine transmissivity levels of pixels  46 P in central region  14 A based on digital input gray levels (e.g., digital input gray values received from storage and processing circuitry  33 ). Modified gray level mapping function  15 B is used to determine transmissivity levels of pixels  46 P′ in border region  14 B based on digital input gray levels. 
     As shown in  FIG. 10 , pixels  46 P′ in border region  14 A are configured to be more transmissive than pixels  46 P in central region  14 B when displaying neutral light having an associated input gray level that is below the light leakage threshold LL. The higher transmissivity of pixels  46 P′ in border region  14 B for darker colors such as black and dark gray helps minimize light leakage in display  14 . 
     Display control circuitry  30  may drive pixels  46 P in central region  14 A according to gray level mapping function  15 A and may drive pixels  46 P′ in border region  14 B according to gray level mapping function  15 B. 
     In the example of  FIG. 10 , modified gray level mapping function  15 B differs from gray level mapping function  15 A only for input gray levels below the light leakage threshold LL. This type of modified gray level mapping function is suitable for arrangements in which light leakage reduction structures  62  are switchable. For example, for input gray levels at or above the light leakage threshold LL, light leakage reduction structures  62  may be turned off and the pixel transmissivity of pixels  46 P′ in border region  14 B may be the same as pixels  46 P in central region  14 A. 
     In arrangements where light leakage reduction structures  62  are not switchable, display control circuitry  30  may use a modified gray level mapping function that is different from gray level mapping function  15 A for input gray levels above the light leakage threshold LL. For example, display control circuitry  30  may use modified gray level mapping function  15 C to map input gray levels to pixel transmissivity. Because light leakage reduction structures are non-switchable and are configured to reduce the intensity of backlight received by pixels  46 P′ regardless of input gray level value, the transmissivity of pixels  46 P′ may be higher than that of pixels  46 P for input gray values above the light leakage threshold LL. 
     Gray level mapping functions  15 A,  15 B, and  15 C may be mathematical expressions computed by a processor or other circuitry in device  10 , may be lookup tables stored in memory in device  10 , and/or may be implemented using any other suitable circuitry in device  10 . 
       FIGS. 11 and 12  are cross-sectional side views of a portion of display  14  illustrating how static light leakage reduction structures  62 A may be configured to reduce the amount of backlight that reaches display pixels  46 P′ in light leakage regions of display  14  such as light leakage region  14 B. 
     In the example of  FIG. 11 , light scatting features  62 A (e.g., bumps, pits, roughened surfaces, or other suitable light-scattering features) are used to reduce the amount of light that is emitted from region  14 B of top surface  78 T of light guide plate  78  relative to the amount of light that is emitted from region  14 A of top surface  78 T of light guide plate  78 . This may be achieved by configuring light-scattering features  62 A (e.g., configuring the density, size, shape, location, and/or type of light-scattering features  62 A) to ensure that the amount of backlight  44  that is scattered upwards through pixels  46 P′ is half as much (or any other suitable ratio) as the amount of backlight  44  that is scattered upwards through pixels  46 P. For example, in a light guide plate configuration that uses pits to scatter backlight, the pits that are formed on the portion of light guide plate  78  that lies under pixels  46 P′ may have half the density of pits that are formed on the portion of light guide plate  78  that lies under pixels  46 P (or any other suitable ratio). 
     If desired, light-scattering features  62 A may be configured in a gradient fashion such that the transmittance of upper surface  78 T of light guide plate  78  decreases gradually from central portion  14 A to peripheral portion  14 B. This type of configuration is shown in  FIG. 12 . As shown in  FIG. 12 , the density of light-scattering features  62 A is gradually reduced from a first density under pixels  46 P to a second density under pixels  46 P′. The gradual decrease in transmittance of top surface  78 T ensures that pixels  46 P′ receive backlight with lower intensity than that received by pixels  46 P without producing image artifacts on display  14 . 
       FIG. 13  is a cross-sectional side view of a portion of display  14  illustrating how light leakage reduction structures  62 B may be configured to reduce the amount of backlight that reaches display pixels  46 P′ in light leakage regions of display  14  such as light leakage region  14 B. 
     In the example of  FIG. 13 , light leakage reduction structures are formed from a shutter module such as shutter module  62 B that is interposed between display module  46  and backlight structures  42 . Shutter module  62 B may have local dimming elements such as local dimming element  62 L configured to control the amount of backlight  44  that passes through shutter module  62 B. As shown in  FIG. 13 , local dimming element  62 L lies under pixels  46 P′ in region  14 B of display  14 , and, when activated, blocks a portion of backlight  44  so that the intensity of backlight  44 ′ received by pixels  46 P′ is reduced compared to the intensity of backlight received by pixels  46 P. If desired, there may be a single contiguous local dimming element under display pixels  46 P′ in region  14 B (e.g., a single contiguous local dimming element having a rectangular ring shape as shown in  FIG. 9 , or having any other suitable shape that matches the shape of region  14 B of pixels  46 P′) or there may be multiple local dimming elements under pixels  46 P′ (e.g., one local dimming element under each pixel  46 P′, one local dimming element under each set of 4 pixels  46 P′, one local dimming element under each set of 8 pixels  46 P′, etc.) 
     In one suitable embodiment, local dimming elements  62 L in shutter module  62 B are formed from polymer-dispersed liquid crystal structures. This type of configuration is shown in  FIG. 14 . As shown in  FIG. 14 , local dimming element  62 L includes a polymer-dispersed liquid crystal layer such as polymer-dispersed liquid crystal layer  94 . Shutter modules having local dimming elements  62 L formed from polymer-dispersed liquid crystal structures are sometimes referred to as polymer-dispersed liquid crystal modules. 
     Polymer-dispersed liquid crystal layer  94  includes liquid crystal droplets  96  dispersed in solid polymer matrix  102 . Layer  94  is interposed between upper substrate  90  and lower substrate  100 . Upper and lower substrate layers  90  and  100  are formed from transparent substrate layers such as clear layers of plastic or glass. Upper substrate layer  90  is coated with a conductive material such as transparent conductive material  92  (e.g., a thin coating of indium tin oxide or other transparent conductive material). Lower substrate layer  100  is also coated with a conductive material such as transparent conductive material  98  (e.g., a thin coating of indium tin oxide or other transparent conductive material). Polymer-dispersed liquid crystal layer  94  is sandwiched between conductive coatings  92  and  98  (sometimes referred to herein as upper and lower ITO coatings). 
     Upper and lower ITO coatings are used for applying electric fields to polymer-dispersed liquid crystal layer  94  and thereby controlling the amount of light transmitted through local dimming element  62 L. The transmission of light through layer  94  of local dimming element  62 L depends on the amount of scattering that occurs as light strikes layer  94 . The amount of light-scattering in turn depends on the orientation of liquid crystal droplets  96 . In the absence of an applied voltage, liquid crystal droplets  96  are dispersed in polymer  102  in a random array. This maximizes the amount of scattering that occurs as light is incident on layer  94  and therefore minimizes the transmission of light through local dimming element  62 L. When a voltage is applied across layer  94 , the electric field that is produced across layer  94  causes liquid crystal droplets  96  to align with the electric field. This minimizes the amount of scattering that occurs as light is incident on layer  94  and therefore maximizes the transmission of light through local dimming element  62 L. 
     Display control circuitry  30  (e.g., a timing controller) that controls display module  46  can also be used in adjusting the electric field across layer  94  in local dimming element  62 L, thereby selectively increasing or decreasing the intensity of backlight received by pixels in display  14 . For example, display control circuitry  30  may activate shutter module  62 B by adjusting the electric field across layer  94  such that a portion of backlight  44  incident upon dimming element  62 L is blocked, thereby reducing the amount of backlight received by overlapping pixels  46 P′ in region  14 B. 
     Using a switchable light leakage reduction structure such as shutter module  62 B of  FIGS. 12 and 13  may allow display  14  to retain a high dynamic range in light leakage region  14 B. For example, when input gray levels for pixels  46 P′ are below the light leakage threshold LL, the transmissivity of the pixel may be increased and display control circuitry  30  may adjust shutter module  62 B such that local dimming element  62 L reduces the intensity of backlight received by pixels  46 P′ by a corresponding amount (e.g., an amount corresponding to the increase in transmissivity). On the other hand, when input gray levels to pixels  46 P′ are at or above the light leakage threshold LL, the pixel transmissivity need not be modified and display control circuitry  30  may adjust shutter module  62 B such that local dimming element  62 L is fully transmissive (e.g., display control circuitry  30  may deactivate local dimming element  62 L). This type of configuration ensures that pixels  46 P′ are able to accurately display high gray levels (e.g., gray levels at or above the light leakage threshold LL) with the desired luminance. 
       FIG. 15  is a flow chart of illustrative steps involved in operating a display such as display  14  using static (e.g., non-switchable) light leakage reduction structures such as light leakage reduction structures  62 A of  FIGS. 11 and 12 . 
     At step  200 , display control circuitry  30  may receive an input gray value corresponding to an intensity of light to be displayed by a given pixel in display  14 . 
     At step  202 , display control circuitry  30  may determine whether the display pixel is in a light leakage region of display  14  such as border region  14 B of  FIG. 9 . If it is determined that the pixel is not in a light leakage region of display  14 , processing proceeds to step  204 . 
     At step  204 , display control circuitry  30  may drive the display pixel according to an unmodified gray level mapping function such as gray level mapping function  15 A of  FIG. 10 . Because the pixel is not within light leakage region  14 B (i.e., because the pixel is within central region  14 A and does not overlap low-density light scatting features  62 A in light guide plate  78 ), the backlight received by the pixel has an intensity such that the output gray level displayed by the pixel corresponds to the input gray level. 
     If it is determined during step  202  that the pixel is within a light leakage region such as light leakage region  14 B, processing proceeds to step  206 . 
     At step  206 , display control circuitry  30  may drive the display pixel according to a modified gray level mapping function such as modified gray level mapping function  15 C of  FIG. 9 . Because the pixel is within border region  14 B, low-density light-scattering features  62 A in light guide plate  78  ensure that the backlight received by the pixel has a reduced intensity that corresponds to the increased pixel transmissivity such that the output gray level corresponds to the original input gray level. 
       FIG. 16  is a flow chart of illustrative steps involved in operating a display such as display  14  using dynamic (e.g., switchable) light leakage reduction structures such as light leakage reduction structures  62 B of  FIGS. 13 and 14 . 
     At step  300 , display control circuitry  30  may receive an input gray value corresponding to an intensity of light to be displayed by a given pixel in display  14 . 
     At step  302 , display control circuitry  30  may determine whether the display pixel is in a light leakage region of display  14  such as border region  14 B of  FIG. 9 . If it is determined that the pixel is not in a light leakage region of display  14 , processing proceeds to step  304 . 
     At step  304 , display control circuitry  30  may drive the display pixel according to an unmodified gray level mapping function such as gray level mapping function  15 A of  FIG. 10 . Because the pixel is not within light leakage region  14 B (i.e., because the pixel is within central region  14 A and does not overlap local dimming element  62 L), the backlight received by the pixel has an intensity such that the output gray level displayed by the pixel corresponds to the input gray level. 
     If it is determined during step  302  that the pixel is within a light leakage region such as border region  14 B, processing proceeds to step  306 . 
     At step  306 , display control circuitry  30  may determine whether the input gray level is below a threshold gray level (e.g., light leakage threshold gray level LL of  FIG. 10 ). If it is determined that the input gray level is equal to or greater than the light leakage threshold gray level LL, processing proceeds to step  308 . 
     At step  308 , display control circuitry  30  may deactivate light leakage reduction structures  62 B such that the local dimming element  62 L under the display pixel is fully transmissive. This may include, for example, using display control circuitry  30  to adjust the electric field across layer  94  ( FIG. 14 ) such that all of backlight  44  incident upon structures  62 B overlapping the pixel is transmitted and allowed to reach the pixel. Processing may then proceed to step  312 . 
     If it is determined during step  306  that the input gray level is less than the light leakage threshold gray level LL, processing proceeds to step  310 . 
     At step  310 , display control circuitry  30  may activate light leakage reduction structures  62 B such that the local dimming element  62 L under the display pixel is only partially transmissive, thereby reducing the intensity of backlight that reaches the display pixel. This may include, for example, using display control circuitry  30  to adjust the electric field across layer  94  ( FIG. 14 ) such that a portion of backlight  44  incident upon structures  62 B overlapping the pixel is blocked from reaching the pixel. Processing may then proceed to step  312 . 
     At step  312 , display control circuitry  30  may drive the display pixel according to a modified gray level mapping function such as modified gray level mapping function  15 B of  FIG. 9 . The intensity of backlight received by the display pixel and the transmissivity of the display pixel may be coordinated such that the intensity of light displayed by the display pixel corresponds to the input gray level. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20130626
Publication Date: 20160524
Grant Date: 20160524
Priority Date: 20130626
Inventors: CHEN CHENG
RUNDLE NICHOLAS A.
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F1/133512", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/36", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F2001/133601", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/0238", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B6/0061", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F2001/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2310/0232", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/3406", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133601", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/3406", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133512", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2320/0238", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B6/0061", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133512", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/36", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2320/0238", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133601", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/3406", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2310/0232", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2310/0232", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/36", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B6/0061", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133388", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 52115169