Abstract:
An improved system and method for controlling the brightness of indicator lights used on portable information handling systems. Various embodiments of the invention optimize the output of the indicator lights in accordance with detected ambient light levels. The brightness of the indicator lights can be adjusted automatically in accordance with a fixed response curve or manually by user inputs. In some embodiments, the brightness is adjusted in accordance with user-designated preferences that are stored in a brightness preference table and correlated with detected ambient light levels.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates in general to the field of information handling system displays, and more particularly to a system and method for controlling indicator lights in portable information handling systems.  
         [0003]     2. Description of the Related Art  
         [0004]     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.  
         [0005]     Information handling systems configured as portable units have grown in popularity among users over the past several years. Portable information handling systems generally integrate in a single housing a display, internal power source and processing components, such as the CPU and hard disk drive, so that a user can carry the portable system from place to place while the system is operating. As processing components have decreased in size and increased in performance, portable information handling systems are often able to pack processing capabilities into a relatively small housing that are comparable to the capabilities available from desktop systems. One important consideration to achieving portability is reducing the power consumption of the components within the system so that the internal power will support operations for a long enough time period. Generally, the most practical display solution for portable systems both in terms of size and power consumption are liquid crystal display (LCD) panels. LCD panels have a backlight, such as cool cathode florescent light (CCFL) that illuminates the display through a panel of pixels. An image is generated by altering the light-absorbing characteristics of the pixels so that backlight passing through a pixel has a desired color.  
         [0006]     In addition to the CCFL, most portable information handling systems comprise a plurality of indicator lights that consume battery power. For example, some portable information handling systems have up to 48 configurable LED indictor lights. Each LED consumes up to 100 mW of power at maximum brightness, resulting in a possible power consumption of 4.8 W when all LEDs are active. This level of power consumption can result in a significant drain on the battery. Furthermore, a large number of active indicator lights can be distracting in a dim environment.  
         [0007]     In view of the foregoing, there is a need for a system and method to control the brightness and power consumption of indicator lights on portable information handling systems both to optimize power consumption and to enhance the aesthetic appearance of the indicator lights.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention provides an improved system and method for controlling the brightness of indicator lights used on portable information handling systems.  
         [0009]     Various embodiments of the invention optimize the output of the indicator lights in accordance with detected ambient light levels. Control logic is operable to receive signals from an ambient light sensor and to generate appropriate control signals to modify the output of the indicator lights. The brightness of the indicator lights can be adjusted automatically in accordance with a fixed response curve. In some embodiments of the invention, the brightness of the indicator lights is adjusted in accordance with manual user inputs, thereby changing the brightness of the indicator lights from a nominal value associated with a sensed ambient light level to a level manually selected by the user.  
         [0010]     In some embodiments, the brightness is adjusted in accordance with user-designated preferences that are stored in a brightness preference table and correlated with detected ambient light levels. After the user preference data has been stored, subsequent use of the information handling system will result in indicator light brightness levels corresponding to the user-specified settings for predetermined ambient light levels. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     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.  
         [0012]      FIG. 1  is a block diagram of an information handling system having a plurality of indicator lights with ambient light brightness correction;  
         [0013]      FIG. 2  is a block diagram of the functional components of a display management subsystem for controlling the output level of a plurality of indicator lights in a portable information handling system; and  
         [0014]      FIG. 3  is a graphical illustration modification of the brightness of indicator lights in an information handling system using ambient light correction with and without user brightness preference adjustments. 
     
    
     DETAILED DESCRIPTION  
       [0015]     Information handling system display brightness adjustments compensate for both ambient light levels and user brightness preferences at various ambient light levels to provide improved display brightness management with reduced direct user involvement. 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.  
         [0016]     Referring now to  FIG. 1 , a block diagram depicts an information handling system  100  configured as a portable system having a plurality of processing components disposed in a housing  102 . In various embodiments of the invention discussed below, the brightness of the display  104  and a plurality of indicator lights  106  are controlled by a display management system that is operable to receive inputs from an ambient light sensor  108 . The functional components of the information handling system include a processor  110  and various other subsystems  112  understood by those skilled in the art. Data is transferred between the various system components via various data buses illustrated generally by bus  114 . A memory interface  116  is operable to control data stored in various memory devices including a hard drive  118  and RAM  120 . An input/output (I/O) interface  122  controls the transfer of data between the various system components and a plurality of input/output (I/O) devices  124 , such as a keyboard  126 , and various devices that may be attached to the information handling system via a plurality of I/O ports known to those of skill in the art. A display management subsystem  128 , described in greater detail below, is operable to manage power consumption in the information handling system  110  by controlling the power consumption of individual components of the information handling system, such as the display  104  and the indicator lights  106 .  
         [0017]      FIG. 2  is a block diagram illustration of functional components of the display management subsystem  128  for controlling the brightness of the display  104  and indicator lights  106 . The display management subsystem is broadly comprised of an inverter  130 , an embedded controller/super I/O (EC/SIO) module  132 , a graphics processing unit (GPU)  134 , and a brightness control module  136 . The ambient light sensor  108  detects the ambient light level in the vicinity of the information handling system  100  and provides the detected ambient light level to the EC/SIO  132  via an SMBus  131 . In an embodiment of the invention, the ambient light sensor  108  is integrated into the inverter  130 . In other embodiments of the invention, the ambient light sensor  108  can be a separate module that provides an input signal to the EC/SIO  132 .  
         [0018]     The EC/SIO  132  has firmware that automatically adjusts the brightness output from display  104  to compensate for the detected ambient light level. The EC/SIO  132  manages the brightness of the display  104  by controlling the power output of the inverter  130  that is capable of providing incrementally variable power levels to a CCFL  138  in the display  104 .  
         [0019]     In addition to automated adjustments in response to detected ambient light, EC/SIO  132  is operable to accept manual user brightness selections and performs automated user brightness preference adjustments. The GPU  134  is operable to provide DPST backlight image adaptation (BIA) adjustments to the inverter to ensure that the adjustments are not perceptible by a user.  
         [0020]     Manual brightness adjustments are made by the user through keyboard  126  to cause the EC/SIO  132  to generate appropriate commands to increase or decrease the brightness of the display  104 . For instance, each selection of control key and an up arrow on keyboard  126  can be interpreted by EC/SIO as a command to incrementally increase display brightness above the brightness level set in response to the detected ambient light level. Firmware embedded in the EC/SIO  132  analyzes the manual user adjustments to establish a user brightness preference for the detected ambient light level. The user brightness preference automatically establishes the user&#39;s manually input brightness level for the display brightness if a similar level of ambient light is detected in a subsequent use of display  104 .  
         [0021]     The display management system  128  is also operable to control the indicator lights  106  by using many of the functional components discussed above regarding the control of the display  104 . The EC/SIO  132  manages the brightness of the indicator lights  106  by generating appropriate control signals for use by brightness control module  136 . As discussed above, the ambient light sensor  108  detects the ambient light level and provides the detected ambient light level to EC/SIO  132  via the SMBus  131 . The EC/SIO  132  has firmware that automatically adjusts the brightness of the display lights  106  to compensate for the detected ambient light level. The EC/SIO  132  is also operable to accept manual user brightness selections and performs automated user brightness preference adjustments to control the output of the indicator lights  106 .  
         [0022]     As is the case for controlling the display  104 , manual brightness adjustments can be made by the user through keyboard  126  to cause the EC/SIO  132  to generate appropriate commands to increase or decrease the brightness of the indicator lights  106 . The firmware embedded in the EC/SIO  132  analyzes the manual user inputs to establish a user brightness preference for the detected ambient light level. The EC/SIO  132  also uses the user inputs to automatically establish brightness levels for the indicator lights  106  if a similar level of ambient light is detected in a subsequent user session of the information handling system  100 .  
         [0023]     The EC/SIO  132  is also operable to analyze a user&#39;s brightness preferences for the display  104  and the indicator lights  106  and to store those preferences in a user brightness preference table  140 . The user preferences stored in the brightness preference table  140  can be used by the firmware in the EC/SIO  132  to fine-tune the brightness output of the indicator lights  106  for various levels of detected ambient light. When the information handling system  100  is powered on and an ambient light level is detected, the EC/SIO  132  is operable to use the data stored in the brightness preference table  140  to generate control signals that are used by the brightness control module  136  to cause the indicator lights  106  to generate light at a predetermined brightness level associated with the detected ambient light level. In various embodiments of the invention, the brightness control module  136  uses varying pulse width modulation (PWM) signals to control the brightness of the indicator lights  106 .  
         [0024]     Manual brightness adjustments entered by a user are used by the EC/SIO  132  to generate control signals to change the brightness level, with each incremental manual input having a corresponding incremental change in brightness. The EC/SIO  132  determines the difference between the predetermined brightness for the detected ambient light level and the user&#39;s manually selected brightness preference and stores that value in user brightness preference table  140 . When, in a subsequent use of the system, the same ambient light level is detected, the EC/SIO  132  automatically generates control signals that are used by the brightness control module to compensate for the user preference that was previously manually selected at that ambient light level. In one embodiment, EC/SIO  132  analyzes user brightness preferences by storing user preferences manually input by a user for a plurality of predetermined ambient light levels. In an alternative embodiment, the EC/SIO  132  predicts user brightness preferences by applying a model to historical manual brightness adjustments made by a user. In yet another embodiment, the EC/SIO  132  allows direct access by a user to user brightness preference table  38  so that the user may directly input the user&#39;s brightness preferences at various detected ambient light levels.  
         [0025]      FIG. 3  is a graphical illustration of nominal brightness adjustments  142  which have a substantially linear relationship to detected ambient light. Preference based brightness adjustments  144  have a non-linear relationship relative to the detected ambient light with the user preferences for various levels of ambient light changing the brightness output compared with the nominal ambient light brightness adjustment.  
         [0026]     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.