PATENT DOCUMENT

Publication Number: US-8248554-B2
Application Number: US-48830409-A
Country: US
Kind Code: B2

Title: Edge-lit backlight unit with thin profile

Abstract:
An edge-lit backlight unit for a display is provided. In one embodiment, the backlight unit may include a light guide configured to receive light from a source and emit such light in a broad distribution to a turning film disposed over the light guide. The turning film may be configured to redirect light received from the light guide toward a normal of the turning film. In one embodiment, the light guide may be configured such that peak light distribution therefrom occurs at an incident angle of approximately sixty degrees, with broad light distribution substantially occurring over an angular range between incident angles of thirty-five and eighty-five degrees. Additionally, in one embodiment, the turning film may include multiple prisms that receive and redirect the light emitted from the light guide, and that include apex angles of less than or about sixty degrees. Additional edge-lit backlight units and methods are also disclosed.

Claims:
1. A display backlight unit comprising:
 a light guide configured to receive light from a light source at a first surface and to emit the light from a second surface such that the light emitted from the second surface is at an angle of between thirty-five degrees and eighty-five degrees measured with respect to a normal of the second surface; and 
 a turning film disposed over the second surface of the light guide, the turning film including a plurality of prisms configured to receive and redirect the light emitted from the second surface of the light guide. 
 
     
     
       2. The display backlight unit of  claim 1 , wherein the angle is between fifty-five and sixty-five degrees. 
     
     
       3. The display backlight unit of  claim 2 , wherein the angle is substantially sixty degrees. 
     
     
       4. The display backlight unit of  claim 1 , comprising the light source, wherein the light source includes at least one of a cold-cathode fluorescent lamp or a light-emitting diode. 
     
     
       5. The display backlight unit of  claim 1 , comprising a diffuser disposed over the turning film. 
     
     
       6. The display backlight unit of  claim 1 , wherein the turning film includes a diffusing portion configured to diffuse the redirected light received from the plurality of prisms. 
     
     
       7. A display backlight unit comprising:
 a light guide configured to receive light from a light source and to emit the light from an emission surface of the light guide, wherein the light guide includes anisotropic optical elements configured to refract the light received from the light source such that the light emitted from the emission surface is substantially distributed over an angular range, measured with respect to a normal of the emission surface, of greater than thirty-five degrees and less than ninety degrees; and 
 a redirection layer disposed over the emission surface for receiving the light from the emission surface of the light guide. 
 
     
     
       8. The display backlight unit of  claim 7 , wherein the anisotropic optical elements are disposed on at least one of the emission surface or an additional surface of the light guide opposite the emission surface. 
     
     
       9. The display backlight unit of  claim 8 , wherein the anisotropic optical elements include substantially ellipsoid lenses. 
     
     
       10. The display backlight unit of  claim 7 , wherein the angular range is less than sixty degrees. 
     
     
       11. The display backlight unit of  claim 10 , wherein the angular range is substantially centered at a sixty-degree angle with respect to a normal of the emission surface. 
     
     
       12. The display backlight unit of  claim 11 , wherein the angular range is substantially located between angles of thirty-five degrees and eighty-five degrees with respect to the normal. 
     
     
       13. A liquid crystal display comprising:
 a liquid crystal display panel; and 
 an edge-lit backlight unit configured to output light to the liquid crystal display panel, the backlight unit including:
 a light source; 
 a light guide configured to emit light received from the light source, the light guide including optical elements on at least one surface of the light guide that are configured to scatter the light emitted from the light guide within a primary distribution range of thirty-five degrees to eighty-five degrees measured with respect to a normal of an emission surface of the light guide, and wherein the optical elements are further configured to emit light at an angle between fifty-seven degrees and sixty-three degrees with respect to the normal; 
 a turning film disposed over the light guide and including a plurality of prisms configured to receive light emitted from the light guide and redirect such light toward the liquid crystal display panel, wherein the plurality of prisms includes prisms having apex angles of less than or approximately sixty degrees. 
 
 
     
     
       14. The liquid crystal display of  claim 13 , wherein each prism of the plurality of prisms is symmetric. 
     
     
       15. The liquid crystal display of  claim 13 , comprising a reflector disposed adjacent an additional surface of the light guide opposite the emission surface and configured to direct light incident on a reflective surface of the reflector toward the emission surface of the light guide. 
     
     
       16. The liquid crystal display of  claim 13 , wherein the reflector comprises at least one of a specular reflector or a diffuse reflector. 
     
     
       17. An electronic device comprising:
 one or more input structures; 
 a storage structure capable of storing one or more executable routines; 
 a processor capable of receiving inputs from the one or more input structures and of executing the one or more executable routines; and 
 a liquid crystal display (LCD) capable of displaying an output of the processor, wherein the LCD includes:
 a liquid crystal display panel; and 
 an edge-lit backlight unit configured to output light to the liquid crystal display panel, the backlight unit including:
 a light guiding plate; 
 a light source adjacent a lateral edge of the light guiding plate; and 
 a turning film disposed over the light guiding plate, the turning film including a plurality of prisms on a surface of the turning film facing the light guiding plate; 
 wherein the light guiding plate is configured to receive light from the light source at the lateral edge such that the received light propagates through the light guiding plate and is redirected by lenses of the light guiding plate to emit light to the turning film, and wherein light emitted from an emission surface of the light guiding plate is substantially distributed over an angular range of at least thirty-five degrees and less than ninety degrees measured with respect to a normal of the emission surface. 
 
 
 
     
     
       18. The electronic device of  claim 17 , wherein the edge-lit backlight unit includes only a single turning film. 
     
     
       19. The electronic device of  claim 17 , wherein the turning film is configured such that peak light distribution from the LCD occurs at a non-zero angle with respect to a normal of the LCD. 
     
     
       20. The electronic device of  claim 17 , wherein the electronic device includes at least one of a computer, a monitor, or a handheld electronic device. 
     
     
       21. A method of redirecting light in an edge-lit backlight unit, the method comprising:
 emitting light from an emission surface of a light guide of an edge-lit backlight unit such that the light is substantially distributed over an angular range, measured with respect to a normal of the emission surface, of greater than thirty-five degrees and less than eighty-five degrees; 
 receiving light emitted from the light guide on a first surface of a prism formed on a receiving surface of a turning film; 
 transmitting the received light to a second surface of the prism, the prism including an apex angle between the first and second surfaces of fifty degrees to sixty-five degrees; 
 reflecting the transmitted light from the second surface toward an emission surface of the turning film opposite the receiving surface; and 
 emitting the reflected light from the emission surface of the turning film. 
 
     
     
       22. The method of  claim 21 , wherein emitting the reflected light from the emission surface of the turning film includes emitting the reflected light such that the emitted light exhibits a peak intensity substantially along a normal of the emission surface. 
     
     
       23. The method of  claim 21 , wherein receiving light emitted from the light guide includes receiving light emitted from the light guide on respective first surfaces of a plurality of prisms formed on the receiving surface, the plurality of prisms including first and second prisms different from one another. 
     
     
       24. The method of  claim 21 , wherein receiving light emitted from the light guide includes receiving light emitted from the light guide on respective first surfaces of a plurality of prisms of the receiving surface of the turning film, and wherein the receiving surface is configured to reduce moiré effects on an image generated on a display including the display backlight unit. 
     
     
       25. A display backlight unit comprising:
 a light guide configured to receive light from a light source at a first surface and to emit the light from a second surface such that the light emitted from the second surface includes a peak direction of transmittance angle of between forty-five degrees and seventy degrees, wherein the light guide includes anisotropic optical elements including substantially ellipsoid lenses disposed on at least one of the emission surface or an additional surface of the light guide opposite the emission surface configured to refract the light received from the light source; and 
 a turning film disposed over the second surface of the light guide, the turning film including a plurality of prisms configured to receive and redirect the light emitted from the second surface of the light guide. 
 
     
     
       26. A display backlight unit comprising:
 a light guide configured to receive light from a light source and to emit the light from an emission surface of the light guide, wherein the light guide includes anisotropic optical elements including substantially ellipsoid lenses configured to refract the light received from the light source and which are disposed on at least one of the emission surface or an additional surface of the light guide opposite the emission surface; and 
 a redirection layer disposed over the emission surface for receiving the light from the emission surface of the light guide. 
 
     
     
       27. A liquid crystal display comprising:
 a liquid crystal display panel; and 
 an edge-lit backlight unit configured to output light to the liquid crystal display panel, the backlight unit including:
 a light source; 
 a light guide configured to emit light received from the light source, the light guide including anisotropic optical elements on at least one surface of the light guide that are configured to refract the light emitted from the light guide within a primary distribution range of thirty degrees to eighty-five degrees measured with respect to a normal of an emission surface of the light guide, and wherein the optical elements are further configured to emit light at a peak direction of transmittance angle between fifty-seven degrees and sixty-three degrees with respect to the normal, and wherein the optical elements include substantially ellipsoid lenses; and 
 a turning film disposed over the light guide and including a plurality of prisms configured to receive light emitted from the light guide and redirect such light toward the liquid crystal display panel, wherein the plurality of prisms includes prisms having apex angles of less than or approximately sixty degrees. 
 
 
     
     
       28. An electronic device comprising:
 one or more input structures; 
 a storage structure capable of storing one or more executable routines; 
 a processor capable of receiving inputs from the one or more input structures and of executing the one or more executable routines; and 
 a liquid crystal display (LCD) capable of displaying an output of the processor, wherein the LCD includes:
 a liquid crystal display panel; and 
 an edge-lit backlight unit configured to output light to the liquid crystal display panel, the backlight unit including:
 a light guiding plate; 
 a light source adjacent a lateral edge of the light guiding plate; and 
 a turning film disposed over the light guiding plate, the turning film including a plurality of prisms on a surface of the turning film facing the light guiding plate; 
 wherein the light guiding plate is configured to receive light from the light source at the lateral edge such that the received light propagates through the light guiding plate and is redirected by lenses, including anisotropic substantially ellipsoid lenses, of the light guiding plate to emit light to the turning film, and wherein light emitted from an emission surface of the light guiding plate is distributed over an angular range of at least thirty degrees. 
 
 
 
     
     
       29. A method of redirecting light in an edge-lit backlight unit, the method comprising:
 receiving light emitted from a light guide of an edge-lit backlight unit on a first surface of a prism formed on a receiving surface of a turning film, wherein the light guide includes anisotropic elements, and wherein the anisotropic elements include substantially ellipsoid lenses; 
 transmitting the received light to a second surface of the prism, the prism including an apex angle between the first and second surfaces of fifty degrees to sixty-five degrees; 
 reflecting the transmitted light from the second surface toward an emission surface of the turning film opposite the receiving surface; and 
 emitting the reflected light from the emission surface of the turning film.

Description:
BACKGROUND 
     1. Technological Field 
     This relates generally to backlight units of electronic display panels, such as liquid crystal displays. 
     2. Description of the Related Art 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     Liquid crystal displays (LCDs) are commonly used as screens or displays for a wide variety of electronic devices, including such consumer electronics as televisions, computers, and handheld devices (e.g., cellular telephones, audio and video players, gaming systems, and so forth). Such LCD devices typically provide a flat display in a relatively thin package that is suitable for use in a variety of electronic goods. In addition, such LCD devices typically use less power than comparable display technologies, making them suitable for use in battery-powered devices or in other contexts where it is desirable to minimize power usage. 
     LCDs typically include an LCD panel having, among other things, a liquid crystal layer and various circuitry for controlling orientation of liquid crystals within the layer to modulate an amount of light passing through the LCD panel. Further, while certain LCDs may operate by reflecting and modulating passage of light from a source positioned in front of the LCD panel (e.g., ambient light), many LCDs include a light source, such as an internal light source, that illuminates the LCD panel from behind. For example, in a direct-lit backlight configuration, a light source (e.g., a lamp or light emitting diodes) is provided behind, and directs light to, an LCD panel. To reduce the thickness of the LCD, an edge-lit backlight configuration may instead be used, in which the light source is oriented to illuminate an edge of a light guide, which in turn distributes such light to the LCD panel. While edge-lit backlights are generally thinner than direct-lit backlights, various conventional edge-lit backlights may exhibit certain disadvantages, such as reduced brightness and/or narrow acceptable viewing angles. 
     SUMMARY 
     Certain aspects of embodiments disclosed herein by way of example are summarized below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms an invention disclosed and/or claimed herein might take, and that these aspects are not intended to limit the scope of any invention disclosed and/or claimed herein. Indeed, any invention disclosed and/or claimed herein may encompass a variety of aspects that may not be set forth below. 
     The present disclosure generally relates to an edge-lit backlight unit for a display. In one embodiment, the edge-lit backlight unit includes a light guide that receives light from a light source, and emits this light in a broad distribution to a turning film. In one embodiment, the light guide includes anisotropic optical elements that refract light such that the light emitted to the turning film falls within a broad distribution, such as over a range of approximately fifty degrees. Additionally, the turning film may be configured to redirect this broad distribution of light toward a normal direction with respect to the backlight unit. In one embodiment, an edge-lit backlight unit may exhibit increased luminance, improved viewing angles, or both when compared to conventional edge-lit backlight units. Additionally, in one embodiment, the edge-lit backlight unit may be thinner than certain conventional edge-lit backlight units. 
     Various refinements of the features noted above may exist in relation to various aspects of the present invention. Further features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present invention alone or in any combination. Again, the brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of embodiments of the present invention without limitation to the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Advantages of the present disclosure may become apparent upon reading the following detailed description and upon reference to the drawings in which: 
         FIG. 1  is a block diagram of exemplary components of an electronic device, in accordance with aspects of the present disclosure; 
         FIG. 2  is a perspective view of a computer in accordance with aspects of the present disclosure; 
         FIG. 3  is a perspective view of a handheld electronic device in accordance with aspects of the present disclosure; 
         FIG. 4  is an exploded view of a liquid crystal display (LCD) including a backlight unit in accordance with aspects of the present disclosure; 
         FIG. 5  depicts an example of a backlight unit including a wedge-shaped light guide and brightness enhancement films; 
         FIG. 6  depicts another example of a backlight unit including a light guide having prismatic features and a turning film having prisms configured to receive light from the light guide; 
         FIG. 7  generally illustrates the turning of a narrow distribution of light emitted from the light guide of  FIG. 6  by a prism of the turning film also of  FIG. 6 ; 
         FIG. 8  is a partially exploded view generally depicting a backlight unit having a light guide that emits light over a broader distribution range than that of  FIGS. 6 and 7 , in accordance with aspects of the present disclosure; 
         FIG. 9  generally illustrates the turning of the broad distribution of light emitted from the light guide of  FIG. 8  by a prism of the turning film of  FIG. 8  in accordance with aspects of the present disclosure; 
         FIG. 10  is a flowchart representative of operation of the prism of  FIG. 9  in receiving and redirecting light from the light guide in accordance with aspects of the present disclosure; 
         FIG. 11  is a top plan view of the light guide of  FIGS. 8 and 9 , which includes anisotropic optical elements to emit light over a broad distribution range in accordance with aspects of the present disclosure; 
         FIG. 12  is a partially exploded view generally depicting a backlight unit having a light guide that emits light over a broad distribution range and a multi-function film in accordance with aspects of the present disclosure; 
         FIG. 13  is a partially exploded view generally depicting a backlight unit that does not include a diffusion layer over a turning film of the backlight unit in accordance with aspects of the present disclosure; 
         FIG. 14  is a partially exploded view generally depicting a backlight unit having a turning film that includes differently-shaped prisms in accordance with aspects of the present disclosure; 
         FIG. 15  is a graph representing the luminance of the backlight unit of  FIG. 6  as a function of viewing angle along its major and minor axes; 
         FIG. 16  is a graph generally representing the improvement in minor-axis luminance of a backlight unit emitting a broad distribution of light from a light guide to a turning film provided in accordance with aspects of the present disclosure; and 
         FIG. 17  is a perspective view of a computer generally depicting the possibility of biasing of the peak luminance direction of a backlight unit and a display in accordance with aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     One or more specific embodiments will be described below. These described embodiments are provided only by way of example, and do not limit the scope of the present disclosure. Additionally, in an effort to provide a concise description of these exemplary embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     When introducing elements of various embodiments described below, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, while the term “exemplary” may be used herein in connection to certain examples of aspects or embodiments of the presently disclosed subject matter, it will be appreciated that these examples are illustrative in nature and that the term “exemplary” is not used herein to denote any preference or requirement with respect to a disclosed aspect or embodiment. Additionally, it should be understood that references to “one embodiment,” “an embodiment,” “some embodiments,” and the like are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the disclosed features. 
     The present application is generally directed to edge-lit backlight units for displays. Particularly, the present application discloses edge-lit backlight units that provide improved luminance in a thinner profile compared to certain traditional backlight units employing brightness enhancement films. Additionally, the presently disclosed backlight units may also exhibit better viewing angle performance than other traditional backlight units. As discussed in greater detail below, in some embodiments, edge-lit backlight units in accordance with the present techniques include a light guide that emits light in a broad distribution to a turning film, which generally operates to redirect such light out of the backlight unit, such as to an LCD panel of a display. 
     With these foregoing features in mind, a general description of electronic devices that may employ such an edge-lit backlight unit is provided below. As may be appreciated, electronic device may include various internal and/or external components which contribute to the function of the device. For instance,  FIG. 1  is a block diagram illustrating components that may be present in one such electronic device  10 , and which may allow device  10  to function in accordance with the techniques discussed herein. Those of ordinary skill in the art will appreciate that the various functional blocks shown in  FIG. 1  may include hardware elements (including circuitry), software elements (including computer code stored on a computer-readable medium, such as a hard drive or system memory), or a combination of both hardware and software elements. It should further be noted that  FIG. 1  is merely one example of a particular implementation and is merely intended to illustrate the types of components that may be present in electronic device  10 . For example, in the presently illustrated embodiment, these components may include display  12 , I/O ports  14 , input structures  16 , one or more processors  18 , memory device  20 , non-volatile storage  22 , expansion card(s)  24 , networking device  26 , and power source  28 . 
     With regard to each of these components, it is first noted that display  12  may be used to display various images generated by device  10 . In various embodiments, display  12  may be a liquid crystal display (LCD), a cathode ray tube (CRT) display, or any other suitable display. Additionally, in certain embodiments of electronic device  10 , display  12  may be provided in conjunction with a touch-sensitive element, such as a touchscreen, that may be used as part of the control interface for device  10 . 
     I/O ports  14  may include ports configured to connect to a variety of external devices, such as a power source, headset or headphones, or other electronic devices (such as handheld devices and/or computers, printers, projectors, external displays, modems, docking stations, and so forth). I/O ports  14  may support any interface type, such as a universal serial bus (USB) port, a video port, a serial connection port, an IEEE-1394 port, an Ethernet or modem port, and/or an AC/DC power connection port. 
     Input structures  16  may include the various devices, circuitry, and pathways by which user input or feedback is provided to processor(s)  18 . Such input structures  16  may be configured to control a function of electronic device  10 , applications running on device  10 , and/or any interfaces or devices connected to or used by device  10 . For example, input structures  16  may allow a user to navigate a displayed user interface or application interface. Non-limiting examples of input structures  16  include buttons, sliders, switches, control pads, keys, knobs, scroll wheels, keyboards, mice, touchpads, and so forth. User interaction with input structures  16 , such as to interact with a user or application interface displayed on display  12 , may generate electrical signals indicative of user input. These input signals may be routed via suitable pathways, such as an input hub or bus, to processor(s)  18  for further processing. 
     Additionally, in certain embodiments, one or more input structures  16  may be provided together with display  12 , such an in the case of a touchscreen, in which a touch sensitive mechanism is provided in conjunction with display  12 . In such embodiments, the user may select or interact with displayed interface elements via the touch sensitive mechanism. In this way, the displayed interface may provide interactive functionality, allowing a user to navigate the displayed interface by touching display  12 . 
     Processor(s)  18  may provide the processing capability to execute the operating system, programs, user and application interfaces, and any other functions of the electronic device  10 . Processor(s)  18  may include one or more microprocessors, such as one or more “general-purpose” microprocessors, one or more special-purpose microprocessors and/or ASICS, or some combination of such processing components. For example, processor(s)  18  may include one or more reduced instruction set (RISC) processors, as well as graphics processors, video processors, audio processors, and the like. As will be appreciated, processor(s)  18  may be communicatively coupled to one or more data buses or chipsets for transferring data and instructions between various components of electronic device  10 . 
     Programs or instructions executed by processor(s)  18  may be stored in any suitable manufacture that includes one or more tangible, computer-readable media at least collectively storing the executed instructions or routines, such as, but not limited to, the memory devices and storage devices described below. Also, these programs (e.g., an operating system) encoded on such a computer program product may also include instructions that may be executed by processor(s)  18  to enable device  10  to provide various functionalities, including those described herein. 
     The instructions or data to be processed by processor(s)  18  may be stored in a computer-readable medium, such as memory  20 . Memory  20  may include a volatile memory, such as random access memory (RAM), and/or a non-volatile memory, such as read-only memory (ROM). Memory  20  may store a variety of information and may be used for various purposes. For example, memory  20  may store firmware for electronic device  10  (such as basic input/output system (BIOS)), an operating system, and various other programs, applications, or routines that may be executed on electronic device  10 . In addition, memory  20  may be used for buffering or caching during operation of the electronic device  10 . 
     The components of device  10  may further include other forms of computer-readable media, such as non-volatile storage  22  for persistent storage of data and/or instructions. Non-volatile storage  22  may include, for example, flash memory, a hard drive, or any other optical, magnetic, and/or solid-state storage media. Non-volatile storage  22  may be used to store firmware, data files, software programs, wireless connection information, and any other suitable data. 
     The embodiment illustrated in  FIG. 1  may also include one or more card or expansion slots. The card slots may be configured to receive one or more expansion cards  24  that may be used to add functionality, such as additional memory, I/O functionality, or networking capability, to electronic device  10 . Such expansion cards  24  may connect to device  10  through any type of suitable connector, and may be accessed internally or external to the housing of electronic device  10 . For example, in one embodiment, expansion cards  24  may include a flash memory card, such as a SecureDigital (SD) card, mini- or microSD, CompactFlash card, Multimedia card (MMC), or the like. Additionally, expansion cards  24  may include one or more processor(s)  18  of the device  10 , such as a video graphics card having a GPU for facilitating graphical rendering by device  10 . 
     The components depicted in  FIG. 1  also include network device  26 , such as a network controller or a network interface card (NIC). In one embodiment, network device  26  may be a wireless NIC providing wireless connectivity over any 802.11 standard or any other suitable wireless networking standard. Network device  26  may allow electronic device  10  to communicate over a network, such as a personal area network (PAN), a local area network (LAN), a wide area network (WAN), or the Internet. Further, electronic device  10  may connect to and send or receive data with any device on the network, such as portable electronic devices, personal computers, printers, and so forth. Alternatively, in some embodiments, electronic device  10  may not include a network device  26 . In such an embodiment, a NIC may be added as one expansion card  24  to provide similar networking capability as described above. 
     Further, device  10  may also include power source  28 . In one embodiment, power source  28  may be one or more batteries, such as a lithium-ion polymer battery or other type of suitable battery. The battery may be user-removable or may be secured within the housing of electronic device  10 , and may be rechargeable. Additionally, power source  28  may include AC power, such as provided by an electrical outlet, and electronic device  10  may be connected to power source  28  via a power adapter. This power adapter may also be used to recharge one or more batteries of device  10 . 
     Electronic device  10  may take the form of a computer system or some other type of electronic device. Such computers may include computers that are generally portable (such as laptop, notebook, tablet, and handheld computers), as well as computers that are generally used in one place (such as conventional desktop computers, workstations and/or servers). In certain embodiments, electronic device  10  in the form of a computer may be a model of a MacBook®, MacBook® Pro, MacBook Air®, iMac®, Mac® mini, or Mac Pro® available from Apple Inc. of Cupertino, Calif. By way of example, electronic device  10  in the form of laptop computer  30  is illustrated in  FIG. 2  in accordance with one embodiment. Depicted computer  30  includes housing  32 , display  12  (e.g., LCD  34  or some other suitable display), input/output ports  14 , and input structures  16 . 
     In one embodiment, input structures  16  (such as a keyboard and/or touchpad) may be used to interact with computer  30 , such as to start, control, or operate a graphical user interface (GUI) or applications running on computer  30 . For example, a keyboard and/or touchpad may allow a user to navigate a user interface or application interface displayed on display  12 . 
     As depicted, electronic device  10  in the form of computer  30  may also include various I/O ports  14  to allow connection of additional devices. For example, I/O ports  14  may include a USB port, a DVI port, or some other port suitable for connecting to another electronic device, a projector, a supplemental display, and so forth. In addition, computer  30  may include network connectivity, memory, and storage capabilities, as described with respect to  FIG. 1 . As a result, computer  30  may store and execute a GUI and other applications. 
     Although electronic device  10  is generally depicted in the context of a computer in  FIG. 2 , electronic device  10  may also take the form of other types of electronic devices. In some embodiments, various electronic devices  10  may include cellular telephones, media players for playing music and/or video, personal data organizers, handheld game platforms, cameras, and/or combinations of such devices. For instance, as generally depicted in  FIG. 3 , device  10  may be provided in the form of handheld electronic device  36  that includes various functionalities (such as the ability to take pictures, make telephone calls, access the Internet, communicate via email, record audio and/or video, listen to music, play games, connect to wireless networks, and so forth). By way of further example, handheld device  36  may be a model of an iPod® or iPhone® available from Apple Inc. In other embodiments, however, other types of handheld devices (such as other media players for playing music and/or video, personal data organizers, handheld game platforms, and/or combinations of such devices) may also be suitably provided as electronic device  10 . 
     Handheld device  36  of the presently illustrated embodiment includes an enclosure or body that protects the interior components from physical damage and shields them from electromagnetic interference. The enclosure may be formed from any suitable material such as plastic, metal or a composite material and may allow certain frequencies of electromagnetic radiation to pass through to wireless communication circuitry within handheld device  36  to facilitate wireless communication. 
     Handheld electronic device  36  also may include various input and output (I/O) ports  14  that allow connection of the handheld device  36  to external devices. For example, one I/O port  14  may be a port that allows the transmission and reception of data or commands between the handheld electronic device  36  and another electronic device, such as a computer. Such an I/O port  14  may be a proprietary port from Apple Inc. or may be an open standard I/O port. 
     In the depicted embodiment, the enclosure includes user input structures  16  through which a user may interface with the device. Each user input structure  16  may be configured to help control a device function when actuated. For example, in a cellular telephone implementation, one or more input structures  16  may be configured to invoke a “home” screen or menu to be displayed, to toggle between a sleep and a wake mode, to silence a ringer for a cell phone application, to increase or decrease a volume output, and so forth. 
     In the depicted embodiment, handheld device  36  includes display  12 , which may be in the form of LCD  34 . Such LCD  34  may be used to display graphical user interface (GUI)  38  that allows a user to interact with handheld device  36 . GUI  38  may include various layers, windows, screens, templates, or other graphical elements that may be displayed in all, or a portion, of LCD  34 . Generally, GUI  38  may include graphical elements that represent applications and functions of the electronic device, such as icons  40 , as well as other images representing buttons, sliders, menu bars, and the like. Icons  40  may correspond to various applications of the electronic device that may open upon selection of a respective icon  40 . Furthermore, selection of a particular icon  40  may lead to a hierarchical navigation process, such that selection of the particular icon  40  leads to a screen that includes one or more additional icons or other GUI elements. Icons  40  may be selected via a touchscreen included in display  12 , or may be selected by one or more user input structures  16 , such as a wheel or button. Of course, LCD  34  may also be used to display other data, images, or visual outputs. 
     One example of LCD display  34  is depicted in  FIG. 4  in accordance with one embodiment. LCD display  34  generally includes LCD panel  42  and backlight unit  44 , which may be assembled within frame  46 . As may be appreciated, LCD panel  42  may include numerous pixels configured to selectively modulate the amount and color of light passing from backlight unit  44  through LCD panel  42 . For example, LCD panel  42  may include a liquid crystal layer, one or more thin film transistor layers configured to control orientation of liquid crystals of the liquid crystal layer via an electric field, and polarizing films, which cooperate to enable LCD panel  42  to control the amount of light emitted by each pixel. Additionally, LCD panel  42  may include color filters that allow specific colors of light to be emitted from the pixels (e.g., red, green, and blue). LCD panel  42  may be a twisted nematic (TN) panel, an in-plane switching (IPS) panel, a fringe-field switching (FFS) panel, a vertical alignment panel (e.g., a multi-domain vertical alignment (MVA) panel or a patterned vertical alignment (PVA) panel), variants of the foregoing types of panel, or any other suitable panel. 
     As discussed in greater detail below, backlight unit  44  includes light source  48 . Light from light source  48  is routed through portions of backlight unit  44  (e.g., a light guide and optical films) and generally emitted toward LCD panel  42 . In various embodiments, light source  48  may include a cold-cathode fluorescent lamp (CCFL), one or more light emitting diodes (LEDs), or any other suitable source(s) of light. Although various LCD displays  34  may be incorporated into computers  30  or handheld devices  36 , it is noted that other LCD displays  34  may be incorporated into televisions, computer monitors, and other types of devices. 
     More detailed examples of portions of backlight units are depicted in  FIGS. 5 and 6 . In both of these figures, the illustrated backlight units are edge-lit backlight units. In such edge-lit backlight units, a light source is positioned to provide light to a lateral edge of a light guide, which emits light from an emission surface (e.g., an upper surface of the light guide). For instance, backlight unit  50  of  FIG. 5  includes light guide  52 , such as a light guiding plate, positioned adjacent light source  54 . Although light source  54  is generally depicted as a portion of a CCFL, light source  54  may also or instead include any suitable light source, such as LEDs. 
     Light from light source  54  may generally propagate through light guide  52  via total internal reflection at upper and lower surfaces of light guide  52 , and may ultimately be emitted therefrom toward various optical films  56 . For example, light guide  52  may include certain optical features on either or both of the upper and lower surfaces of light guide  52  that disrupt total internal reflection, allowing light to pass from light guide  52  to optical films  56 . Such optical features may include, for example, printed dots or micro-lenses on either or both of the upper and lower surfaces of light guide  52 . In other instances, however, the generally wedge-shaped light guide  52  may gradually decrease the angle of incidence of the reflected light, eventually allowing the light to escape light guide  52 . Although depicted as generally wedge-shaped in  FIG. 5 , it is noted that light guide  52  may be provided in other forms, such as a generally planar light guide. 
     For backlight units  50  in which light guide  52  includes printed dots or micro-lenses, such optical features typically scatter light over a very broad range of distribution (i.e., greater than ninety degrees). Optical films  56  may function to focus this very broad light distribution for output to an LCD panel, thereby increasing apparent brightness of the LCD panel. For instance, optical films  56  may include brightness enhancement films  58  and  60 , which generally increase “on-axis” brightness (i.e., the brightness of backlight unit  50  along a normal of an upper surface of backlight unit  50 ). Such brightness enhancement films  58  and  60  typically include prisms formed on an upper surface of such films and generally directed away from light guide  52 , as generally depicted in  FIG. 5 . 
     Brightness enhancement films  58  and  60  generally increase on-axis brightness of backlight unit  50  by permitting certain received light to be emitted within a desired viewing range about the normal, while the other received light may be recycled by reflecting the light toward reflector  66 . For example, the lower surface of brightness enhancement film  58  may reflect light incident at an angle greater than the critical angle of the surface, and may refract light incident at an angle less than the critical angle. Of light refracted by the lower surface, some of this light may be reflected back toward light guide  52  by one or more surfaces of the prisms of brightness enhancement film  58 , while other light will be emitted from the prisms. Brightness enhancement film  60  may operate in a similar manner. 
     Light reflected from brightness enhancement films  58  and  60  may be again reflected by reflector  66  back toward brightness enhancement films  58  and  60 . This recycled light may then pass through the brightness enhancement films  58  and  60  or may again be reflected, depending on the angle at which the recycled light approached such films. Backlight unit  50  may also include diffuser layers  62  and  64  to scatter light and provide a more uniform light distribution from backlight unit  50 . Backlight unit  50 , and other backlights similarly having a light guide that emits light over a very broad distribution range and one or more brightness enhancement films for increasing on-axis brightness, is typically referred to as a “PMMA” backlight, generally named for the material commonly used to form light guide  52  (i.e., polymethyl-methacrylate, an acrylic glass). It is noted, however, that light guide  52  may be formed of other suitable materials. 
     In the example depicted in  FIG. 6 , backlight unit  68  includes light source  70  configured to output light to light guide  72 . Light guide  72  includes a multiple micro-prisms  74  that disrupt total internal reflection of light received from light source  70 , causing such light to be emitted from light guide  72  (either directly or via reflection from reflector  66 ) toward turning film  76  and diffuser layer  78 . Such backlight units including a light guide having micro-prisms and one or more turning films to redirect light from the light guide are typically referred to as prism backlight units. Unlike the very broad light distribution from light guide  52  discussed above with respect to the PMMA backlight of  FIG. 5 , light guide  72  instead emits light from its upper surface to turning film  76  in a very narrow distribution range (i.e., less than or approximately equal to thirty degrees). Turning film  76  includes small prisms  80  formed on a lower surface of turning film  76  and generally projecting toward adjacent light guide  72 . Rather than operating to focus a very broad distribution of light, such as discussed above with respect to brightness enhancement films  58  and  60 , turning film  76  operates to receive the very narrow distribution of light and generally redirects such light toward a normal of a display including backlight unit  68 , thereby allowing on-axis viewing by a user of such a display. 
     Such operation may be better understood with reference to  FIG. 7 , which generally depicts the redirection of light from light guide  72  by a single prism  80  in prism backlight unit  68 . In such units, rays of light  82  emitted from light guide  72  may be directed toward prism  80 . Light output from light guide  72  may include a peak direction of transmittance  84 , and such light may substantially fall within distribution range  86 . In backlight unit  68 , and in other prism backlight units, light is emitted from light guide  72  at a steep incident angle  88  (e.g., approximately seventy-five degrees) and falls within a narrow range of distribution generally represented by angle  90  (e.g., less than or approximately equal to thirty degrees). 
     Light  82  received at surface  92  of prism  80  is refracted toward surface  96 , as generally indicated by reference numeral  94 . Such light  82  may then be reflected by surface  96  and redirected to pass through turning film  76  (as well as additional layers of a display), as generally indicated by reference numeral  98 . Prism  80  may include apex  100  formed by the intersection of surfaces  92  and  96 , and apex  100  may define apex angle  102 . Traditionally, prism  80  is formed such that apex angle  102  is substantially equal to sixty-eight degrees. 
     As previously noted, displays including prism backlight units often exhibit greater brightness than PMMA backlight units when viewed from a typical viewing angle (e.g., at a normal to the backlight unit and display), while PMMA backlights typically provide better viewing angles (e.g., less image distortion when viewing, at a wide angle, an image on a display including a backlight) than prism backlight units. In accordance with the present techniques, however, various backlight units that may provide greater brightness than traditional PMMA backlight units and wider viewing angles than traditional prism backlight units are described below with reference to  FIGS. 8-17 . 
     For example, backlight unit  104 , which may provide enhanced viewing angles in comparison to backlight unit  68 , is depicted in  FIG. 8  in accordance with one embodiment. Backlight unit  104  includes light guide  106  configured to receive light on an edge thereof from light source  108 , such as one or more LEDs or a CCFL. Light guide  106  includes upper emission surface  110 , from which light is emitted toward other layers of backlight unit  104 , and lower surface  112 . Backlight unit  104  may also include reflector  114  configured to direct light toward emission surface  110 . Reflector  114  may include a specular reflector or a diffuse (e.g., Lambertian) reflector. As discussed in greater detail below, light guide  106  may be configured with anisotropic optical elements that allow light to escape light guide  106  in distribution range  116  broader than that of light emitted from light guide  72  discussed above. The light emitted from light guide  106  is generally directed toward prisms  118  formed on a lower surface of turning film  120 . Prisms  118  may be arranged on turning film  120  in a periodic manner or with some degree of apparent randomness. Additionally, prisms  118  may be substantially linear along their axial length, or may include curvature (e.g., a wave pattern). 
     Additional details with respect to backlight unit  104  are described below with reference to  FIGS. 9-11  in accordance with one embodiment.  FIG. 9  generally depicts details regarding light emitted from light guide  106  and the redirection of such light by a single prism  118  in accordance with method  122  generally depicted in  FIG. 10 . Additionally,  FIG. 11  generally depicts an example of anisotropic optical features formed on a surface of light guide  106  for emitting light in a broad pattern suitable for turning by turning film  120 . 
     By way of example, and as generally depicted in  FIG. 9 , light  124  may be emitted from emission surface  110  of light guide  106  toward prism  118 . Light  124  falls within distribution range  116 , which includes peak transmittance direction  126 . Whereas the distribution of light from light guide  72  is quite narrow and at a steep incident angle, light  124  emitted by light guide  106  falls over broader distribution range  116  and includes shallower incident angles. For instance, angle of incidence  130  of peak transmittance direction  126  may be between fifty degrees and seventy-five degrees measured from normal  132 , rather than approximately equal to seventy-five degrees as discussed above with respect to light guide  72 . More particularly, in certain embodiments, angle of incidence  130  may be between about fifty-five degrees to about sixty-five degrees, between about fifty-seven degrees to about sixty-three degrees, or may be substantially equal to sixty degrees. 
     Broad distribution range  116  may include an angular range, generally represented by angle  134 , greater than that provided by prism light guide  72 . For example, the angular range of distribution  116  within a plane perpendicular to both light source  108  and emission surface  110  of light guide  106  (e.g., the field of view depicted in  FIG. 9 ) may be greater than thirty degrees. In various embodiments, this angular range may be between about thirty-five degrees and about ninety degrees, such as approximately: thirty-five degrees, forty degrees, forty-five degrees, fifty degrees, fifty-five degrees, sixty degrees, sixty-five degrees, seventy degrees, seventy-five degrees, eighty degrees, eighty-five degrees, or ninety degrees. By way of further example, in one embodiment the angular range represented by angle  134  may be approximately fifty degrees wide, and may be substantially located between incidence angles of thirty-five degrees and eighty-five degrees with respect to normal  132 , as generally represented by angles  136  and  138 . Further, in this or other embodiments, distribution range  116  may be substantially centered on peak transmittance direction  126  (i.e., approximately half of the light within distribution  116  includes incident angles greater than angle  130 , while the other approximate half includes incident angles less than angle  130 ). 
     As generally indicated by reference numeral  140  in  FIG. 10 , light  124  from light guide  106  may be received at first surface  142  of prism  118 . Light  124  incident on first surface  142  may be refracted and transmitted to second surface  148  of prism  118 , as generally represented by reference numeral  144 . Refracted light  146  may be reflected from second surface  148 , as generally indicated by reference numeral  150 , and this reflected light  152  may be emitted from emission surface  156  of turning film  120 , as generally indicated by reference numeral  154 . Further, light  152  may then pass through any additional layers of backlight unit  104  or a display (e.g., LCD  34 ), such as diffuser  158  ( FIG. 8 ) and various layers of LCD panel  42  ( FIG. 4 ). It is noted that diffuser  158  may function to partially scatter light received from turning film  120  and provide a more uniform light distribution from backlight unit  104 . Further, the inclusion of diffuser  158  may prevent or reduce the magnitude of moiré patterns, which may otherwise result from interference between prisms  118  and pixels of LCD panel  42 , in images displayed by LCD  34 . In some embodiments, the haze value of diffuser  158  may be thirty percent or greater, although this value may be smaller in other embodiments. 
     First and second surfaces  142  and  148  of prism  118  may intersect at apex  162 , which generally defines apex angle  164 . In contrast to turning film  76  ( FIG. 6 ) having prisms  80  with apex angles  102  greater than sixty-five degrees (e.g., sixty-eight degrees), apex angle  164  of prism  118  depicted in  FIG. 9  includes a smaller apex angle  164  less than sixty-five degrees, such as between about fifty degrees and sixty-five degrees. More particularly, in one embodiment apex angle  164  is substantially equal to sixty degrees, although other apex angles  164 , such as any other angle between about fifty degrees and sixty-five degrees, may be employed in full accordance with the present techniques. 
     Rays of light  152  may be emitted at various angles  160  with respect to the base of prism  118  or turning film  120 . The resulting angle  160  for a particular ray of light depends on various geometric parameters, such as angle of incidence  130  for the particular light ray emitted from light guide  106  and various aspects of prism  118  (e.g., apex angle  164 , base angles of prism  118 , and so forth). Some or all prisms  118  of turning film  120  may be symmetric about a line or plane of symmetry, as generally represented by reference numeral  166 , or may be asymmetric. For instance, such symmetric prisms  118  may include an axial cross-section generally in the form of an isosceles triangle, with substantially identical base angles that are different than apex angle  164 , or generally in the form of an equilateral triangle having base angles substantially identical to each other and to apex angle  164 . Prism  118  may be configured in some embodiments such that peak light distribution occurs along a common normal of the base of prism  118 , emission surface  156 , and LCD panel  42  (i.e., such that peak light distribution is orthogonal to such surfaces), or may be configured such that peak light distribution occurs at a non-perpendicular angle  160  with respect to such surfaces. 
     As noted above, and in contrast to light guide  72 , light guide  106  may include various anisotropic optical elements to provide a broader distribution of light at generally shallower angles of incidence to turning film  120 . For example, as depicted in  FIG. 11  in accordance with one embodiment, light guide  106  includes anisotropic optical elements  174 , such as generally elongated (e.g., elliptical or ellipsoid) lenses, formed on surface  176  of light guide  106 . For example, such anisotropic optical elements  174  may be formed on one or both of emission surface  110  and lower surface  112  of light guide  106 . Light from light source  108  may be received at lateral surface  178  and may generally propagate through light guide  106  toward opposite surface  180  by way of total internal reflection. Anisotropic optical elements  174 , such as elongated lenses, may disrupt such total internal reflection and generally emit light in distribution patterns  116  as described above. Such elongated lenses or other anisotropic optical elements may be arranged in a pattern on surface  176  or may be randomized. Further, in one embodiment, the relative density of optical elements  174  on surface  176  may increase as a function of distance from lateral surface  178  to facilitate evenness of light emission from light guide  106 . Although anisotropic optical elements  174  are generally depicted as elongated lenses in the present illustrated embodiment, any other suitable anisotropic elements (e.g., various prisms) capable of providing light distribution  116  may be used in full accordance with the present techniques. 
     Additional embodiments of various backlight units in accordance with the present techniques are depicted in  FIGS. 12-14 . For instance, as depicted in  FIG. 12 , backlight unit  184  may include multi-function film  186  that operates to both turn and diffuse light received from light guide  106 . For example, light guide  106  may receive light from light source  108 , and may include emission surface  110  and lower surface  112  as generally described above. Light may be emitted from emission surface  110  within distribution range  116  and toward turning prisms  118  of multi-function film  186 . Prisms  118  may operate to redirect received the light in the manner discussed above with respect to  FIGS. 9 and 10 . Additionally, multi-function film  186  may also include an integrated diffusion layer  188  for diffusing the redirected light, rather than a separate diffuser  158  ( FIG. 8 ). In some embodiments, the haze value of integrated diffusion layer  188  may be thirty percent or greater, although lesser values may be employed in other embodiments. The use of multi-function film  186 , rather than separate turning film  120  and diffuser  158 , may result in a reduction in the thickness of backlight unit  184  in comparison to backlight unit  104 . 
     In other embodiments, it may be desirable to omit diffusion layers (e.g., diffuser  158  and/or integrated diffusion layer  188 ) over prisms  118 , as generally illustrated with respect to backlight unit  194  in  FIG. 13 . In one such embodiment, diffusion may instead be accomplished by applying certain haze to some other layer of the display, such as a polarizing layer of LCD panel  42 . In yet another embodiment generally depicted in  FIG. 14 , backlight unit  204  may include turning film  206  having prisms  118  different from one another, and generally provided with certain disorder that may, among other things, reduce or prevent moiré patterns in images rendered on display  34  including such backlight unit  204 . The disorder of prisms  118  may be provided through variation of any suitable parameter, such as prism angles, height, orientation, and the like; by providing a random speckle pattern on surfaces of prisms  118 ; or in some other fashion. As may be appreciated from the above discussion of other embodiments, light received by prisms  118  may be redirected and emitted from emission surface  208  of turning film  206 . Backlight unit  204  may include diffuser  158 , an integrated diffusion layer (e.g., diffusion layer  188 ), or may omit such a diffusion layer over prisms  118 . 
     As generally depicted in  FIGS. 15 and 16 , viewing angles for a display including an edge-lit backlight unit configured in accordance with the present techniques (e.g., backlight units  104 ,  184 ,  194 , and  204 ) may be significantly improved in comparison to those for a display incorporating a traditional prism backlight unit, such as backlight unit  68 . In  FIG. 15 , graph  220  generally depicts luminance (represented along vertical axis  222 ) as a function of viewing angle (represented along horizontal axis  224 ). Curve  226  generally represents the luminance of the display at different viewing angles along the major axis of the display (e.g., the horizontal axis), while curve  228  generally represents luminance at viewing angles along a minor axis (e.g., the vertical axis) of the display. As generally indicated in graph  220 , luminance of a display including a traditional prism backlight unit decreases at a significantly greater rate for changes in viewing angle along the minor axis than changes in the major axis. 
     Conversely, in one embodiment an edge-lit backlight unit configured in accordance with the present techniques may enable substantially uniform luminance response for changes in viewing angle along the major and minor axes of a display, as generally illustrated in  FIG. 16 . Graph  230  depicts luminance of such a display as a function of viewing angle along vertical and horizontal axes  232  and  234  of graph  230 . Luminance response for variations in viewing angle along a major axis of the display is represented by curve  236 , while that for variance in viewing angle along a minor axis of the display is represented by curve  238 . As may be determined from a comparison of graphs  220  and  230 , improved viewing angles along a minor axis of a display may be obtained through use of an edge-lit backlight unit configured in accordance with the present techniques. Additionally, such an edge-lit backlight unit may provide peak luminance levels greater than that provided by traditional PMMA backlight units by significantly reducing the amount of light lost by the backlight unit. Still further, edge-lit backlight units in accordance with the present techniques may have fewer optical layers, and hence a thinner profile, than traditional PMMA backlight units. For instance, whereas PMMA backlight units may include two prism films and two diffusers, backlight unit  104  includes a single prism film (i.e., turning film  120 ) and a single diffuser  158 , while backlight unit  194  includes a single prism film without a diffuser. In some embodiments, the presently disclosed backlight units may be thinner than traditional PMMA backlight units by twenty-five percent or even more. 
     With reference to  FIG. 17  provided in accordance with one embodiment, it is noted that peak luminance may occur along normal  252  of display  12  of computer  30  (or of some other electronic device  10 ), or at a non-orthogonal angle with respect to display  12 , depending on the configuration of the backlight unit. For instance, as generally discussed above with respect to  FIG. 9 , prisms  118  of a turning film in accordance with the present techniques may output light such that peak luminance occurs along a common normal of the turning film and display  12 , as generally indicated by reference numeral  250 . In other embodiments, however, light guide  106 , prisms  118 , or other aspects of the backlight unit may be configured to provide biased angular performance, in which peak luminance (generally represented by reference numeral  254 ) occurs at angle  256  with respect to normal  252 . 
     The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. It should be further understood that the present techniques are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure.

Metadata:
Filing Date: 20090619
Publication Date: 20120821
Grant Date: 20120821
Priority Date: 20090619
Inventors: QI JUN
YIN VICTOR H.
ZHONG JOHN Z.
CHEN WEI
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F1/1335", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B6/0001", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0036", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133615", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0036", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0061", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B6/0053", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B6/0061", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B6/0053", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B6/0053", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 42471423