Patent Publication Number: US-2021183596-A1

Title: Information handling system keyboard discrete row illumination

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. patent application Ser. No. 16/380,025, filed Apr. 10, 2019, entitled “Information Handling System Keyboard Discrete Row Illumination,” naming Jace W. Files and John Trevor Morrison as inventors, which application is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates in general to the field of information handling system keyboards, and more particularly to an information handling system keyboard discrete row illumination. 
     Description of the Related Art 
     As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems. 
     Information handling systems typically accept inputs from keyboards that associate values, such as letter and number values, with presses at individual mechanical keys. For example, information handling systems commonly accept inputs from QWERTY keyboards that interface with a keyboard controller through a cable or wireless signals. For instance, peripheral keyboards often interface through USB cables and/or Bluetooth wireless signals. A typical keyboard has six rows of keys arranged in a rectangular layout adapted in size to accept inputs from fingers spread across the keyboard surface. 
     Portable information handling systems often integrate a keyboard in a portable housing. For example, a portable information handling system includes rotationally coupled housing portions so that a base housing portion integrates a keyboard and supports a lid housing portion that integrates a display held in a raised viewing position. Typically, the integrated keyboard attaches to an upper face of the base housing portion and is exposed and ready for use when the housing portions rotate to an open position. 
     In some usage scenarios, insufficient external light is available to allow an end user to distinguish key values marked on the top of keyboard keys. For instance, some environments in which desktop information handling systems operate have limited ambient light. Similarly, portable information handling systems are often used in low ambient light situations, such as while traveling or at WiFi hotspots. Limited ambient light can make keyboard interactions difficult for end users who struggle to orient their fingers to the base keyboard position. 
     One solution often found in keyboards of portable information handling systems is to illuminate the keys from below so that key value markings are visible in low ambient conditions. Typical keyboard backlight solutions flood the area underneath keyboard keys so that enough light escapes to illuminate individual key markings. For example, openings distributed across the bottom surface of the keyboard allow light to escape from a flood of illumination at the bottom surface in a controlled manner at the upper surface. One problem with this approach is that a good deal of illumination is wasted in order to provide sufficient illumination across the keyboard bottom surface. Inevitably, some shadows will show up at the keys where illumination escapes in an uneven manner. These shadows tend to be worse where the amount of illumination is limited. 
     Increased illumination at a keyboard backlight light results in increased power consumption and typically increases the size and weight of the assembled keyboard. In particular, the Z-height of the keyboard tends to increase with the total amount of illumination created by a keyboard backlight. Typical conventional keyboard backlights send illumination against the keyboard bottom surface from a flexible printed circuit board that integrates LED illumination sources. One typical backlight configuration attaches a flexible printed circuit across a central portion of the keyboard to add 0.3 mm to the keyboard height. Another typical backlight configuration attaches a flexible printed circuit board strip along one side of the keyboard to add 0.4 mm to the keyboard height. Other solutions that attempt to distribute LEDs across a keyboard back surface tend to add height and complexity to the keyboard design. 
     SUMMARY OF THE INVENTION 
     Therefore, a need has arisen for a system and method which illuminates keyboard keys in an energy and size efficient manner. 
     In accordance with the present invention, a system and method are provided which substantially reduce the disadvantages and problems associated with previous methods and systems for backlight illumination of keyboard keys. An information handling system keyboard disposes a lightguide under each of plural key rows to transmit light from a light source to the key rows for backlight illumination of the keys. 
     More specifically, a portable information handling system processes information with processing components disposed in a housing, such as central processing unit (CPU) and memory, and presents the information as visual images at an integrated display. A keyboard integrates in the housing to accept keyed inputs, such as by communicating key touches from membrane to a keyboard controller for use by the CPU. The keyboard includes a backlight disposed below the keys for illumination of the keys, such as when ambient light conditions are low. The backlight includes plural discrete lightguides with each key row of the keyboard having one of the lightguides disposed beneath along the length of keys of the row. A light source disposed at a side edge of the keyboard directs illumination into each of the plural lightguides so that each key row has discrete illumination. A channel defined by each backlight lightguide has a reflective inner surface with openings formed along its length to release illumination proximate to keys of the keyboard with microlenses disposed near the openings to direct illumination to each opening. In one example embodiment, a keyboard controller interfaces with the light source to adapt illumination levels provided to each lightguide based upon conditions at the keyboard, such as type of keyed inputs and rate of keyed inputs. 
     The present invention provides a number of important technical advantages. One example of an important technical advantage is that a keyboard has a reduced size, weight and power consumption while maintaining illumination levels and even distribution of light across keyboard keys. Segmented illumination to provide keyboard backlight, such as across discrete rows, reduces the overall amount of illumination needed to light individual keys in a uniform manner. More efficient distribution of light reduces power consumption associated with keyboard backlight illumination and decreases the number and size of backlights included in the keyboard for reduced keyboard thickness and size. Individualized control of each keyboard key row&#39;s illumination adapts to end user interactions for an improved end user experience and reduced power consumption. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention may be better understood, and its numerous objects, features and advantages made apparent to those skilled in the art by referencing the accompanying drawings. The use of the same reference number throughout the several figures designates a like or similar element. 
         FIG. 1  depicts an exploded view of an information handling system having a keyboard that applies backlight illumination to discrete rows of keys; 
         FIG. 2  depicts a bottom view of a keyboard having backlight illumination provided to discrete rows of keys; and 
         FIG. 3  depicts a side cutaway view of a keyboard backlight having illumination provided to an opening disposed proximate a key. 
     
    
    
     DETAILED DESCRIPTION 
     An information handling system keyboard has discrete illumination provided to key rows. For purposes of this disclosure, an information handling system may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an information handling system may be a personal computer, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the information handling system may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The information handling system may also include one or more buses operable to transmit communications between the various hardware components. 
     Referring now to  FIG. 1 , an exploded view depicts an information handling system  10  having a keyboard  34  that applies backlight illumination to discrete rows  48  of keys  46 . In the example embodiment, information handling system  10  has a portable form factor with a main housing portion  12  rotationally coupled to a lid housing portion  14  by hinges  16 . For example, main housing portion  12  and lid housing portion  14  rotate about hinges  16  between a closed position and an open clamshell position so that a display  17  integrated in lid housing portion  14  is held in a raised view position by main housing portion  12 . In various embodiments, main housing portion  12  may rotate 360 degrees relative to lid housing portion  14  to convert to a tablet mode. Alternatively, lid housing portion  14  may separate from main housing portion  12  to act as a separate tablet system. In one alternative embodiment, keyboard  34  may reside as a peripheral device that is completely separate from information handling system  10 , such as by communicating through a USB cable or with a wireless interface. 
     In the example embodiment, portable information handling system  10  processes information with processing components disposed in main housing portion  12 . For instance, a motherboard  18  couples inside main housing portion  12  and interfaces processing components that cooperate to execute instructions that process information. A central processing unit (CPU)  20  couples to motherboard  18  and executes instructions stored in random access memory (RAM)  22 , such as instructions of an operating system and applications retrieved to RAM  22  from persistent storage of a solid state drive (SSD)  24  or other non-transitory storage device. A chipset  26  manages operation of CPU  20 , such as clock speed, memory access and presentation of visual information as images presented at an integrated display  17 . A keyboard controller (KBC)  28  or other embedded controller interfaces through motherboard  18  to manage power applied to the processing components and input/output device interactions. A wireless network interface card (WNIC) provides a wireless radio interface for communicating with external networks and peripheral devices. In various embodiments, different configurations of hardware and software components may be used in information handling system  10 , and information handling system  10  may work with an integrated or peripheral keyboard. 
     Keyboard  34  assembles over the top of the processing components, such as by coupling to an upper surface  32  of main housing  12 . In the example embodiment, keyboard  34  assembles into a keyboard chassis  36  to rest on top of upper surface  32 . A light source  38  couples to keyboard chassis  36  to provide illumination for a backlight of keyboard  34 . For example, light source  38  has plural light emitting diodes (LEDs) disposed on a flexible printed circuit (FPC) to provide illumination from a side edge of keyboard chassis  36  towards a central position. In one embodiment, light source  38  is disposed outside the perimeter of keyboard chassis  36  so as not to increase the thickness of keyboard  34 . 
     A set of six independent and separate lightguides  40  are disposed on keyboard chassis  36  to accept illumination from light source  38 . In the example embodiment, each key row  48  has one lightguide disposed underneath it and each lightguide  40  extends along the length of each key row  48  to transmit light from light source  38  to the opposing side of keyboard chassis  36 . Each lightguide  40  directs illumination to keys  46  of each key row  48 , such as with openings formed in lightguides  40  below each key  46 . Lightguides  40  have a width that is narrower than the width of keys  46  so that along its length, lightguide  40  falls under the footprint of keys  46  to leave spacing between each lightguide  40 . 
     A membrane  42  fits over lightguides  40  and is supported by keyboard chassis  36  to detect key  46  presses with a matrix that reports the key presses at an output interface  50 . For instance, a key assembly  44  fits over membrane  42  to align keys  46  with associated input locations. Key assembly  44  biases keys  46  away from membrane  42 , such as with a rubber dome, so that an end user press on a key  46  overcomes the bias to hit membrane  42  and report an input through output interface  50 . Backlight illumination is fed from light source  38  through each lightguide  40  along each key row  48  to present out at each key  46  so that the key value is visible. Although the example embodiment is described in terms of a mechanical keyboard having a conventional rubber dome assembly, in alternative embodiments alternative types of key touch detection mechanisms may be used with lightguides  40  adapted as appropriate to align under each key row  48 . 
     Referring now to  FIG. 2 , a bottom view depicts a keyboard  34  having backlight  52  illumination provided to discrete rows of keys. Light source  38  couples to the edge of the assembly of keyboard  34  to direct illumination towards the center of keyboard  34 . For instance, by coupling outside the perimeter of membrane  42 , the Z-height of lightguide  38  may be aligned in an area outside of keyboard  34  so that the overall height of keyboard  34  is not increased due to the height of light source  38 . In the example embodiment, a spacebar backlight lightguide  54  aligns with the lowest key row starting with the “control” key and having a central space bar key, with first and second portions formed and a second light source  38  providing illumination from an opposing side. Dividing spacebar backlight lightguide  54  into two portions reduces illumination at the space bar key, which is generally identifiable by its size. In addition, a lightguide  38  on both sides of keyboard  34  may be used at just spacebar backlight lightguide  54  or may provide illumination to other lightguides as needed. For instance, where each lightguide  38  has one or more LEDs directing light down specific lightguides  40 , illumination from two light sources on opposing ends for less than all the lightguides  40  may highlight certain keys while other keys in other rows having illumination by one light source  38  will have half the relative brightness. In an alternative embodiment, individual LEDs within light source  38  have illumination levels controlled to adapt illumination to different levels at different key rows. 
     In the example embodiment, five additional lightguides  40  couple to keyboard  34  to align with five additional key rows  48 . A shift backlight lightguide  56  aligns underneath a key row that starts with the “shift” key followed by the “Z” key. An anchor backlight lightguide  58  aligns underneath a key row that starts with the “Caps Lock” key followed by the A, S, D, and F anchor keys of the QWERTY keyboard. A tab backlight lightguide  60  aligns underneath a key row that starts with the “Tab” key followed by the “Q” key. A number backlight lightguide  62  aligns underneath a key row that includes numbers 0-9. The uppermost function backlight lightguide  64  aligns underneath a key row that includes function keys. The example embodiment depicts key row alignments associated with a typical information handling system keyboard  34 , however, in alternative embodiments other types of key configurations and different numbers of key rows may be supported. 
     Aligning a lightguide under each key row provides discrete illumination of keyboard keys that help to optimize a keyboard backlight solution. For example, optimizing segmented solutions in rows improves illumination allocation to keys based upon an amount of light needed to illuminated keys under different conditions. Narrow lightguides disposed under each key row have better efficiency for transmitting illumination than does flooding a keyboard undersurface with illumination. For instance, an airgap and reflector system used in between each optimizes light transmission performance to save power with lower illumination levels. Optimized reflectors on three sides of each lightguide without any breaks and a top reflector mask matched to individual key illumination optimizes key lighting to reduce power consumption. This more efficient illumination transmission reduces shadowing at keys to negligible amounts. As depicted in  FIG. 2 , coupling points  66  that couple keyboard  34  to an information handling system  10  may be disposed between lightguides  40  so that the reflection surface of the lightguides is not broken up or disrupted and the keyboard has greater flexibility at assembly. Further adjusting illumination provided to each lightguide allows variance in illumination across a keyboard. 
     Backlight illumination managed by discrete individualized illumination of key rows  48  provides a number of operational modes that improve an end user&#39;s experience while reducing power consumption. For example, when a keyboard is in an idle state for a predetermined amount of time, illumination of only the anchor key row provides an end user with a visible orientation for hand placement while reducing power consumption. As another example, during different types of inputs, specific rows of keys may have enhanced and/or limited illumination. For instance, during rapid typed inputs of letters, an end users&#39; hands tend to cover the anchor key row so that illumination at the anchor key row and below key rows (i.e., shift and control key rows) may be reduced while upper key rows have an increased illumination that allows the end user to stay oriented. Alternatively, while typing is taking place with greater than a predetermined amount or rate of inputs, the function key row may have illumination limited or shut off, since function keys are not typically input values during rapid letter key inputs. Similarly, a number key row may have reduced illumination while letters are typed and increased illumination as numbers are typed. In one example embodiment, a keyboard controller or other embedded controller monitors inputs made at the keyboard keys with a firmware module to determine variances in keyboard row illumination based upon the type and rate of key inputs. In various embodiments, various other factors may be used to adjust key row illumination to achieve a desired user experience and power consumption. 
     Referring now to  FIG. 3 , a side cutaway view depicts a keyboard backlight  52  having illumination provided to an opening  78  disposed proximate a key. In the example embodiment, a single side-oriented LED  68  directs illumination into a lightguide film channel  74  defined on a bottom surface and two side surfaces by a reflector  70  and an upper surface by a reflective front mask  76 . Front mask  76  forms openings  78  proximate to keys targeted for illumination. The size of openings  78  may vary based upon a desired amount of illumination with an increased size available at locations more distal LED  68 . In the example embodiment, a mircorlens array  72  of plural microlenses are disposed proximate each opening  78  to reflect light from channel  74  towards opening  78 . Directing light from LED  68  through channel  74  with breaks only at openings  78  increases the efficiency of light transmission and reduces shadows that interfere with illumination output. By more effectively directing light to desired exit points, channel  74  provides more even light distribution so that lower illumination levels may be used. In the example embodiment, individual control of LED  68  at each of plural lightguides  40  is supported by a keyboard controller, such as through a GPIO or other control interface. 
     Although the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as defined by the appended claims.