Patent Publication Number: US-2022230576-A1

Title: Information handling system blue light exposure system and method

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates in general to the field of information handling system visual image presentation, and more particularly to an information handling system blue light exposure system and method. 
     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. 
     Increased emphasis on working from home has resulted in greater reliance on information handling systems for employee interactions, such as by having meetings through videoconferencing instead of in person. Generally information handling systems output visual images through a display device, such as a liquid crystal display (LCD), organic light emitting diode display (OLED), a Micro-LED display, a QLED display, or similar display devices. In many instances where employees would get a break from viewing information handling system displays to perform employment duties, such as word processing and computer aided design, by leaving screens to have discussions with other employees, now those discussions are also through screen interactions. Although remote interactions offers advantages in terms of work efficiency and isolating to prevent virus spread, the increased amount of screen time can create its own stress. For example, some studies have suggested that exposure to too much blue light in front of a display can produce uncomfortable side effects. Blue light is typically generated when images are defined by pixels of a display that mix red, green and blue light to create colors. The blue portion of the image component may be generated by light emitting diodes (LEDs) used as a backlight for a display or organic light emitting diode (OLED) material that generates light at the application of power to create a color associated with the OLED material. Some evidence suggests that over exposure to blue light in the 415 to 455 nm wavelength can produce retinal damage. Other evidence suggests that exposure to blue light in the 460 to 480 nm wavelength can impact melatonin production, which impacts sleep quality. Other evidence suggests that long term cumulative blue light exposure may lead to phototoxicity that can accelerate eye aging. These effects have led to some concern that the work from home situation faced by many employees could result in over exposure to blue light as screen time increases. 
     One solution to this difficulty is to use less blue light in presenting visual images where possible. For example, one software solution is to reduce the blue light component used to present visual images through a combination of reduced screen brightness, adapting screen colors to match the ambient environment and relying on greater yellow or reddish visual images. Other software solutions offer timed transitions of blue light content to reduce blue light when bedtime approaches. For instance, Microsoft introduced “Night Light” mode in Windows 10 in 2017 to automatically reduce blue light based on time of day. Other software solutions include iris eye protection by IrisTech, f.lux by justgetflux.com and CareUEyes by care-eyes.com. Still other solutions include blue light screen filters and blue light blocking glasses. Although end users perceive reduction of blue light as beneficial in theory, many prefer the more blue images and thus disable the adaptive color and night light options. 
     SUMMARY OF THE INVENTION 
     Therefore, a need has arisen for a system and method which tracks end user cumulative blue light exposure at an information handling system display. 
     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 to manage blue light exposure at an information handling system display. Logic executing on an information handling system processor tracks blue light generated at a display and user presence in a viewing position of the display to determine a cumulative blue light exposure and, at a threshold, presents a message to the end user at the display regarding the cumulative blue light exposure. 
     More specifically, an information handling system processes information with a processor that executes instructions and a memory that stores the information and instructions. A graphics processor further processes the information to define visual images with pixel values for a display frame. The graphics processor communicates the pixel values to the display through a display frame buffer. A blue light manager executing on the processor tracks the visual images defined by the pixel values to determine a blue light component presented at the display. For example, the blue light manager retrieves the display frame buffer and averages the blue light represented by the pixel values. The blue light manager tracks the blue light to determine a cumulative blue light exposure. In one embodiment, cumulative blue light exposure is summed for periods of time during which an end user is present at the display, such as is indicated by a user presence detection device, such as a time of flight sensor. The cumulative blue light exposure may be adjusted based upon a distance of the end user to the display, the size of the display, the brightness setting of the display, the maximum luminance of the display and a blue light component of ambient light conditions sensed at the display. If a threshold of cumulative blue light exposure is detected, the blue light manager issues a message to the end user, such as a suggestion to mitigate the blue light exposure by taking a break, moving further from the display, decreasing blue light content, etc . . . . 
     The present invention provides a number of important technical advantages. One example of an important technical advantage is that a cumulative blue light exposure of an end user at a display is tracked so that, should the end user exceed a threshold of blue light exposure, a notice is provided to the end user who can mitigate the blue light exposure. Tracking of cumulative blue light exposure over time provides a more accurate indication of when an end user should mitigate the effects of blue light, such as by adjusting the color at the display, moving further away from the display screen or taking a rest from viewing the display. An end user experience is enhanced with an ability to view a display with a full color presentation for a longer time period and receiving an indication of when a less robust color presentation should be used. Cumulative blue light exposure is compared against different thresholds to provide an end user with multiple operating conditions and mitigations to adapt display presentations to the end user&#39;s needs so that mitigation steps have less of an impact on the end user experience. 
    
    
     
       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 a block diagram of an information handling system having blue light cumulative exposure monitored at a display; 
         FIG. 2  depicts an example of blue light summation to track cumulative blue light exposure at a display; 
         FIG. 3  depicts a flow diagram of data flows that track cumulative blue light exposure; 
         FIG. 4  depicts a flow diagram of a process for monitoring cumulative blue light exposure at a display; and 
         FIGS. 5A and 5B  depicts a table of an example embodiment of inputs and outputs for a cumulative blue light exposure model that tracks end user cumulative blue light exposure. 
     
    
    
     DETAILED DESCRIPTION 
     An information handling system tracks end user cumulative blue light exposure at a display for improved indications that mitigation of blue light effects should be taken. 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 , a block diagram depicts an information handling system  10  having blue light cumulative exposure monitored at a display  12 . Information handling system  10  processes information by executing instructions on a central processing unit (CPU)  14  that interfaces with a random access memory (RAM)  16  that stores the information and instructions. For example, a solid state drive (SSD)  18  or other non-transient memory provides persistent storage of an operating system and applications that are retrieved to RAM  16  at power up for execution at CPU  14 . A chipset  20  interfaces with CPU  14  to manage processing operations, such as clock speed and memory accesses. A graphics processing unit (GPU)  22  processes the information to generate pixel values for communication to display  12 , which presents the pixel values as a visual image. An embedded controller  24  interfaces with CPU  14  to manage physical operating conditions, such as power and thermal constraints, and to accept end user interactions through input devices, such as a keyboard  26  and mouse  28 . In various embodiments, information handling system  10  may have a portable configuration with display  12  integrated in a housing or a desktop configuration with display  12  interfaced as a peripheral device. Further, information handling system  10  may interface with plural displays, including both integrated and peripheral displays. 
     GPU  22  generates pixel values in display frames that define visual images for presentation on display  12  as a frame of the length and width of pixels  40  to which the pixel values are applied to present the visual image. For instance, pixel values of a display stored in display frame buffer  30  by GPU  22  are communicated through an interface, such as DisplayPort or HDMI ports and cables, to a display frame buffer  32  of display  12  for scanning to pixels  40 . For example, a timing controller  34  interfaces with display frame buffer  32  to scan the pixel values to pixels  40  by setting red material  42 , blue material  44  and green material  46  of each pixel  40  to achieve a color output defined by the pixel value. Timing controller  34  and GPU  30  interface with EDID  36 , which is a flash memory that stores display characteristics, such as the size of the display, the resolution of the display, the maximum luminance of the display and other factors that define how the display presents visual images. Pixels  40  may generate visual images with liquid crystals that filter a backlight by altering transmission of the light with application of an electric field to the liquid crystals, or by organic light emitting diode (OLED) material that generates light in response to a current applied to the material. Over time, OLED material tends to deteriorate so that the amount of illumination provided by a given current will decrease. An OLED degeneration monitor  38  tracks OLED material degeneration so that a consistent image is created by adjusting current applied to the material in response to degeneration. 
     In the example embodiment, cumulative blue light exposure of an end user at display  12  is tracked by a blue light manager  54  that executes on CPU  14 , such as in a display driver of an operating system stored in SSD  18  and retrieved to RAM  16 . In alternative embodiments, blue light manager  54  may execute as software or firmware on other processing resources, such as GPU  22 , embedded controller  24  and timing controller  34 . Blue light manager determines an amount of blue light at a given time by retrieving display characteristics from EDID  38  to determine the size, maximum luminous and brightness of display  12 , and then applies the display characteristics to the visual images presented by display  12  to determine a blue light component of illumination. Blue light manager  54  tracks a cumulative amount of blue light exposure by adding samples of exposure over time when an end user is detected in a viewing position at the display. End user presence may be estimated based upon input detection and content presented at the display, or by directly sensing an end user with a time of flight sensor  48 , eye gaze sensor  52  or other user presence detection device. Blue light exposure may be adjusted further when a distance to the end user is available, such as from the time of flight sensor, or when an eye gaze direction provides an area of focus by the end user on the display versus looking away from a display. In addition, blue light exposure may be adjusted based upon a blue light component of ambient light sensed by an ambient light sensor  50 . Blue light manager  54 , in various embodiments, may determine an amount of blue light emission by monitoring display pixel presentations. For example, blue light manager  54  may: perform screen capture of a display frame where every pixel is analyzed and summed to determine an amount of total blue light from a display; take a linear historgram of the screen and use the average as the total value of blue energy output from the display frame; or estimate blue energy presented by the display based on visual images presented as part of certain applications, such as email, Excel, Power Point, audiovisual players, etc . . . , then determine an average of blue output per application. 
     As an example, blue light manager  54  periodically samples display frames retrieved from display frame buffer  50  and determines a blue light component by averaging the blue light output defined by the pixel values. As an alternative, blue light manager  54  may periodically sample OLED degradation monitor  38  and determine the amount of blue light exposure based upon the degradation of blue OLED material in a sample period. The interval between samples may be varied based upon the type of content presented at display  12 , such as by increasing the number of samples if display content changes more often and decreasing the samples if the display content is static. Over time, the blue light exposure is summed to track a cumulative blue light exposure and compared against one or more thresholds to determine if the end user should be notified so that the end user can take mitigation steps. For example, time in front of the display is based upon user presence detection and the blue light exposure is summed for each sample interval where user presence is detected. In the event that user presence detection is not available, blue light exposure messages may be issued with time periods so that an end user can estimate their cumulative blue light exposure based on their knowledge of viewing time. If user presence information is available, the position of the user, the portion of the display viewed and similar information may be used to obtain more precise estimates of cumulative blue light exposure. Mitigations offered to the end user may include messages recommending a screen break, a greater distance from the display, an automated reduction of blue light illumination with a dark mode or reduced brightness or other suggestions that reduce blue light exposure. The estimate of cumulative blue light exposure can include multiple displays and, if a camera is available, facial recognition to verify that the same user is present during the exposure time. 
     Referring now to  FIG. 2 , an example depicts blue light summation to track cumulative blue light exposure at a display. An end user eye  56  focuses on a display  12  to receive display illumination as indicated by light path  58 . The pixel total illumination for display  12  is the sum of the power P for each pixel location x,y summed for the pixel matrix from i to j. The cumulative blue light energy E is determined from the integral of the power over a start and stop time. For instance, he start and stop times can be based upon detection of an end user viewing the display. As described above, the power of blue illumination at a pixel is based upon the portion of the light in the blue light spectrum of interest, the screen brightness, the distance and other factors. 
     Referring now to  FIG. 3 , a flow diagram depicts data flows that track cumulative blue light exposure. The process starts at step  64  with a reading of the RGB data for pixel values retrieved from a display frame buffer to calculate the display screen energy output in the blue light spectrum. At step  66 , the time of flight sensor data is read to determine user presence and distance of the user to the display screen. At step  68 , the blue light energy exposure is calculated based upon the blue light presented at the display and the end user distance to the display. The blue light energy calculation reflects the amount of blue light energy that the eye is exposed to at a sample time period. At step  70 , the ambient light exposure is read and a blue light component is determined, such as from a measurement of the brightness and temperature color of the ambient light. As an alternative or in addition to the use of an ambient light sensor, a CRGB sensor may be used to capture ambient light brightness and color. Ambient blue light can increase the amount of blue light that the end user experiences and can also increase the impact of blue light where a low ambient light condition increases the eyes absorption of light. At step  72 , threshold values are enabled to use for a comparison with cumulative blue light energy. The threshold values may be individualized for user preference or can be set based on use conditions, such as an end user&#39;s age and sensitivity to blue light. At step  74  a decay function is computed that estimates cumulative blue light exposure versus the thresholds as time passes. At step  76 , the exposure time is monitored versus the thresholds so that messages related to mitigation may be issued at the display if a threshold is exceeded. 
     Referring now to  FIG. 4 , a flow diagram depicts a process for monitoring cumulative blue light exposure at a display. The process starts at step  78 , such as with system power up, and continues to step  80  to determine if an end user is present at the display screen, such as with detection by a time of flight sensor. If not, the process continues to step  82  to track the end user as away from the display screen and to step  84  to adjust the end user cumulative blue light exposure based upon end user recovery due to time away from the display blue light exposure. The process then returns to step  80  to continue monitoring for end user presence. If at step  80  the end use presence is detected, the process continues to step  86  to periodically perform a capture of the display screen frame buffer and calculate blue light content of the digital visual image, such as with a averaging of blue light component of pixel values across the display frame. At step  88 , a distance to the end user and eye gaze of the end user are captured with a time of flight sensor and eye gaze sensor to aid in evaluation of the blue eye light exposure power, such as to decrease the exposure power as distance and increase and where the eye gaze is directed away from the display. At step  90 , ambient light conditions are captured by an ambient light sensor to determine a blue light component in the ambient light and the impact of ambient light on end user absorption of display blue light, such as with increased sensitivity in low ambient light conditions. At step  92 , the display luminance is captured in nits for the display frame buffer using the brightness setting and display EDID maximum luminance. At step  94 , the pixel value, user position, brightness and luminance are applied to a model, such as shown in  FIG. 5 , to calculate an instantaneous blue light exposure for the end user at the periodic sample. At step  96 , the end user exposure and presence data is tracked in a local database. Although the example embodiment determines user blue light exposure with application executing on the system CPU, in alternative embodiments blue light exposure may be tracked at a GPU or at a processing element of the display, such as a timing controller. 
     Once a periodic sample blue light exposure power is determined, the process continues to step  98  to update the end user cumulative blue light exposure and time at the display screen. Once the cumulative blue light exposure is determined, the process continues to step  100  to determine if the end user has exceeded any blue light exposure thresholds. If a threshold is exceeded, the process continues to step  102  to notify the end user that a blue light threshold was exceeded, such as with a message the display or an audible warning. At step  104 , the end user may be offered mitigation steps to reduce the impact of the blue light exposure, such as taking a rest from viewing the display or adjusting the blue light presented at the display. In one alternative embodiment, detection of a threshold may automatically implement mitigation steps, such as commanding a night mode or other reduction in blue light illumination. At step  106  the cumulative blue light exposure is adjusted based upon any mitigation steps that are taken. From step  100 , if no thresholds are met, and step  106 , if mitigation steps are taken, the process continues to step  108  to determine if the information handling system is still in use. If not, the process ends at step  110 . If system use continues, the process returns to step  80  to continue monitoring blue light exposure. 
     Referring now to  FIGS. 5A and 5B , a table depicts an example embodiment of inputs and outputs for a cumulative blue light exposure model that tracks end user cumulative blue light exposure. The example table illustrates inputs retrieved by a cumulative blue light exposure model from a display, including maximum luminance, screen size, brightness setting, color temperature, type of display and the number of displays that are present. In addition, the model tracks end user viewing conditions, such as a viewing distance, ambient light conditions and end user eyewear. In addition, the model tracks the applications active at the display and illumination blue light content presented by the applications, as set forth above. The inputs are applied to generate output parameters that monitor blue light exposure and cumulative exposure over time. For example, ambient and display screen illuminance is added to provide a total illuminance at the end user eyes. From the total illuminance, a blue light short wavelength illuminance is determined based upon the amount of blue light in the display content and the ambient light. The model provides a cumulative blue light exposure in the example of 2.78 hours and sets a discomfort market and time limit for the exposure. In the example, three cumulative exposure time alarms are set to provide notifications to the end user regarding excessive blue light exposure. 
     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.