PATENT DOCUMENT

Publication Number: US-7750282-B2
Application Number: US-12463008-A
Country: US
Kind Code: B2

Title: Dual purpose ambient light sensor

Abstract:
A dual purpose ambient light sensor. More particularly, an ambient light sensor may be provided on an electronic device to aid in controlling the brightness of the illuminators of the device. The ambient light sensor may be mounted in such a way as to detect ambient light when the electronic device is opened or closed so that the device may control the brightness of the illuminators of the device, whether the illuminators are mounted on the outer or inner shell of the device. Further, when the display is closed, the sensitivity of the ambient light sensor may be adjusted appropriately to account for the lesser amount of light that may reach the sensor. Finally, a spacer or light pipe may be provided to allow ambient light to reach the sensor to provide an accurate ambient light reading when the device is in the closed position.

Claims:
1. An apparatus for controlling the brightness of a plurality of illuminators of an electronic device, the electronic device configured to move between an open position and a closed position, the apparatus comprising:
 an ambient light sensor configured on a surface of the electronic device such that the ambient light sensor is exposed when the electronic device is in the open configuration and when the electronic device is in the closed configuration the ambient light sensor is covered; and 
 a control circuit operative to receive an output from the ambient light sensor and configured to control the brightness of a first illuminator in response to ambient light when the electronic device is in the open position and the brightness of a second illuminator in response to ambient light when the electronic device is in the closed position, wherein the first illuminator is configured on the surface. 
 
   
   
     2. The apparatus of  claim 1 , further comprising:
 a spacer located between a top piece of the electronic device and a bottom piece of the electronic device and at least partially defining a path for at least some ambient light to reach the ambient light sensor when the electronic device is in the closed position. 
 
   
   
     3. The apparatus of  claim 1 , further comprising:
 a light pipe configured to channel at least some ambient light to the ambient light sensor when the electronic device is in the closed position. 
 
   
   
     4. The apparatus of  claim 1 , further comprising:
 a translucent window permitting ambient light to pass to the ambient light sensor when the electronic device is in the closed position. 
 
   
   
     5. The apparatus of  claim 1  wherein the electronic device chosen from the group comprising: a computer; a mobile telephone; a computer display; a digital music player; a medical or health device; and an auto-mounted device. 
   
   
     6. The apparatus of  claim 1 , wherein the control circuit is further operative to scale an output from the ambient light sensor when the electronic device is in the closed position. 
   
   
     7. The apparatus of  claim 1 , wherein the second illuminator is an indicator light. 
   
   
     8. The apparatus of  claim 1  wherein the control circuit adjusts the sensitivity of the ambient light sensor when the apparatus is in the closed position. 
   
   
     9. The apparatus of  claim 4 , wherein:
 the translucent window defines a portion of at least a first edge and second edge of the device; 
 the first edge is exposed when the electronic device is in both the open and closed positions; and 
 the second edge is exposed only when the electronic device is in the open position. 
 
   
   
     10. A method for controlling the brightness of at least one illuminator of an electronic device, the electronic device configured to provide an open position and a closed position, the method comprising:
 sensing ambient light using an ambient light sensor configured on a surface of the electronic device such that the ambient light sensor is exposed when the electronic device is in the open configuration and when the electronic device is in the closed configuration the ambient light sensor is covered; 
 using the output of the ambient light sensor to control the brightness of the at least one illuminator when the electronic device is in the open position; 
 providing a path for at least some ambient light to reach the ambient light sensor when the electronic device is in the closed position; and 
 adjusting the sensitivity of the ambient light sensor when the electronic device is in the closed position by scaling the output of the ambient light sensor. 
 
   
   
     11. The method of  claim 10 , further comprising the operation of providing a spacer located between a top piece of the electronic device and a bottom piece of the electronic device. 
   
   
     12. The method of  claim 10 , wherein the path comprises a light pipe angled to transmit at least some ambient light from an exterior of the electronic device to the ambient light sensor. 
   
   
     13. The method of  claim 10 , further comprising the operation of providing a translucent window configured to surround the ambient light sensor. 
   
   
     14. The method of  claim 10 , wherein the ambient light sensor is hidden from view when the electronic device is in the closed position. 
   
   
     15. A computer system, the computer system configured to provide an open position and a closed position, the computer system comprising:
 a display located on an inner surface of the computer system such that the display is exposed when the computer system is in the open configuration and enclosed by the computer system when the computer system is in the closed configuration; 
 at least a first illuminator located on an outer surface of the computer system; and 
 an ambient light sensor located on the inner surface of the computer system such that the ambient light sensor is exposed when the computer system is in the open configuration and when the computer system is in the closed configuration the ambient light sensor is covered, the ambient light sensor configured to control the brightness of the display when the computer system is in the open position and the brightness of the first illuminator when the computer system is in the closed position. 
 
   
   
     16. The computer system of  claim 15  wherein an output of the ambient light sensor is scaled when the computer system is in the closed position. 
   
   
     17. The computer system of  claim 15  further comprising:
 a top piece; 
 a bottom piece; and 
 at least one spacer located between the top piece and the bottom piece and configured to control the amount of ambient light that reaches the ambient light sensor. 
 
   
   
     18. The computer system of  claim 15  further comprising:
 a light pipe configured to control the amount of ambient light that reaches the ambient light sensor. 
 
   
   
     19. The computer system of  claim 15  further comprising:
 a translucent window configured to surround the ambient light sensor; 
 wherein the translucent window controls the amount of ambient light that reaches the ambient light sensor. 
 
   
   
     20. The computer system of  claim 15  wherein the sensitivity of the ambient light sensor is adjusted when the computer system is in the closed position.

Description:
TECHNICAL FIELD 
   This invention relates generally to ambient light sensors in electronic devices, and more specifically to methods and apparatus for a dual purpose ambient light sensor that aids in controlling the brightness of illuminators of the electronic device whether the device is in the open or closed position. 
   BACKGROUND 
   Many portable electronic devices contain ambient light sensors to sense ambient light of the area surrounding the electronic device. The output of these sensors may be utilized by the device to control the brightness of the backlighting of a display or keyboard in response to ambient light. For example, the device may use the ambient light detected by an ambient light sensor to adjust the brightness of an LCD screen of a laptop computer to maintain a relatively uniform appearance under all lighting conditions, from darkness to direct sunlight. Adjusting the brightness of the backlighting of an electronic device may also save battery power, as backlighting often consumes large amounts of battery power. Thus, dimming the backlights of an electronic device may offer both power savings and uniform appearance. 
   The output of the ambient light sensor may also be utilized to control certain lights or luminance effects associated with an electronic device other than the backlighting. For example, many electronic devices contain indicator lights that provide to the user information about the device, such as the operating status. However, in lowlight environments such as a dark room, indicator lights may appear very bright if the luminance of the lights are not adjusting based on the ambient light in the room. Thus, an ambient light sensor may also be located on the outer shell of the electronic device to measure the ambient light and aid in controlling the indicator lights of the outer shell accordingly when the electronic device is in the closed position. 
   Generally, the best place for locating an ambient light sensor on an electronic device is near the illuminator being controlled (e.g. the display or indicator lights) and facing the direction where the ambient light originates. This allows the ambient light sensor to accurately sense the ambient light of the room or surrounding area in order to allow the device to adjust the brightness of the illuminator accordingly. For example, an ambient light sensor utilized in controlling an LCD screen of a laptop computer may be placed on the bezel of the computer, facing the user. This position would provide the optimal location for the ambient light sensor to detect the amount of ambient light falling on the display such that the device may control the brightness of the LCD screen accordingly. 
   Similarly, the best place to locate an ambient light sensor associated with controlling illuminators located on the outer shell of an electronic device would be next the illuminators on the outer shell. This allows the ambient light sensor to accurately sense the ambient light of the room or surrounding area in order to allow the device to adjust the brightness of the illuminators located on the outer shell of the device accordingly. 
   SUMMARY 
   As described above, many ambient light sensors that control a screen display of an electronic device are located near the screen facing the direction where the ambient light originates. However, when the electronic device is in the closed position, an ambient light sensor located near the screen may no longer detect ambient light. Thus, controlling illuminators located on the outer shell of an electronic device may require a second ambient light sensor located on the outer shell of the electronic device. Thus, what is needed is a single ambient light sensor that accurately detects ambient light such that an electronic device may control the brightness of the illuminators of the device accordingly, and in particular when the device is in both the open and closed positions. 
   One embodiment may take the form of an apparatus for controlling the brightness of a plurality of illuminators of an electronic device. The electronic device of the embodiment may be configured to move between an open position and a closed position. Further, the apparatus may comprise an ambient light sensor and a control circuit. The control circuit may be operative to receive an output from the ambient light sensor and configured to control the brightness of a first illuminator when the electronic device is in the open position. The control circuit may be further configured to control the brightness of a second illuminator when the electronic device is in the closed position. 
   Another embodiment may take the form of a method for controlling the brightness of at least one illuminator of an electronic device. The electronic device of the second embodiment may be configured to provide an open position and a closed position. Further, the method may comprise sensing ambient light using an ambient light sensor and using the output of the ambient light sensor to control the brightness of the at least one illuminator when the electronic device is in the open position. The method may further comprise providing a path for at least some ambient light to reach the ambient light sensor when the electronic device is in the closed position and adjusting the sensitivity of the ambient light sensor when the electronic device is in the closed position. 
   Yet another embodiment may take the form of a computer system configured to provide an open position and a closed position. The computer system may comprise a display located on an inner surface of the computer system, at least a first illuminator located on an outer surface of the computer system and an ambient light sensor configured to control the brightness of the display and the brightness of the first illuminator. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  depicts an isometric view of an exemplary laptop or notebook computer in an open configuration with an ambient light sensor located on the bezel of the display screen. 
       FIG. 2  depicts a front view of the exemplary laptop or notebook computer of  FIG. 1  in a closed configuration. 
       FIG. 3   a  depicts an isometric view of a first embodiment illustrating an exemplary laptop or notebook computer in a closed configuration with a translucent window providing a path for ambient light to reach an ambient light sensor. 
       FIG. 3   b  depicts a cross-section view of a second embodiment illustrating an exemplary laptop or notebook computer in a closed configuration with a light pipe providing a path for ambient light to reach an ambient light sensor. 
       FIG. 4  depicts an isometric view of a third embodiment illustrating an exemplary laptop or notebook computer in a closed configuration with spacers providing a path for present ambient light to reach an ambient light sensor. 
       FIG. 5  depicts a side view of a fourth embodiment illustrating a laptop design that allows present ambient light to reach an ambient light sensor when the laptop is in both an open and closed position. 
       FIG. 6  is a flow chart of a fifth embodiment for adjusting the sensitivity of an ambient light sensor when an electronic device is in a closed position. 
       FIG. 7  depicts a block diagram of an apparatus to control the brightness of an illuminator based on ambient light. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   One particular implementation conforming to aspects of the present invention takes the form an electrical device incorporating an ambient light sensor. The embodiment may allow the ambient light sensor to measure ambient light when the electronic device is in both an open and closed position. Accordingly, the ambient light sensor may thus be referred to as a “dual purpose” ambient light sensor. 
   More particularly, the aforementioned embodiment or a method may provide for the ambient light sensor to be placed near an edge of the electronic device. In this manner, the sensor may continue to detect the ambient light present when the electronic device is in the closed position as well as in the open position. To further accommodate the ambient light sensor detecting the present ambient light in the closed position, a spacer or light pipe-type device may be provided to enhance the amount of ambient light reaching the ambient light sensor. 
   Another embodiment may adjust the sensitivity of the ambient light sensor when the electronic device is in a particular position, such as a closed position. By adjusting the sensitivity of the sensor, the implementation may account for a lesser amount of ambient light reaching the sensor when the electronic device is in the closed position. In this manner, the electronic device may use the output provided by the ambient light sensor to adjust the brightness of the illuminators when the device is in both the open and closed positions without requiring a second sensor on the outer shell. 
     FIG. 1  depicts an exemplary laptop or notebook computer in an open configuration with an ambient light sensor located on the bezel of the display screen. It should be noted that the computer  100  shown in  FIG. 1  is depicted as a notebook computer purely for convenience. The computer could be any form of electronic device having an illuminator, such as a desktop computer, handheld computing device, personal digital assistant, mobile telephone, music or audio player (such as an MP3 player), health or medical device, auto/vehicle-mounted device, and so on. Accordingly, a “computer,” as used generally herein, encompasses all such devices and any other electronic device having, or consisting of, an illuminated display, status light, illuminating indicator, backlight or other light-emitting element capable of emitting light at least at two levels. 
   The notebook computer  100  may also include an ambient light sensor (ALS)  102  generally operative to detect ambient light and aid in controlling the brightness of the illuminators accordingly. As discussed above, it may be generally useful to locate the ALS  102  near the illuminator being controlled and facing the direction where the ambient light originates. Thus, as depicted in  FIG. 1 , an ALS  102  used to control the display  104  of the computer  100  may be located on the bezel  106  of the display facing the user. An ALS  102  located on the bezel  106  may provide an effective location to more accurately detect ambient light falling on the display and thus aid in controlling the display  104  brightness to account for such ambient light. 
   In  FIG. 1 , the ALS  102  is depicted as being located on the top bezel of the notebook. However, it should be appreciated that the ALS  102  may be located anywhere on the bezel surrounding the display  104 . For example, the ALS  102  may also be located on either side of the display  104  of the computer  100 . Further, the ALS  102  may also be located on the case  108  of the computer  100  in situations where the ALS  102  aids in controlling the backlight to the keyboard of the computer  100  and/or LCD display  104 . Further still, for aesthetic reasons, the ALS  102  may be located under a speaker grill located on the case of the computer  100 . Generally, the ALS  102  may be located in any position on the computer  100  that allows the ALS  102  to accurately control the brightness of an illuminator to account for the local ambient light. 
     FIG. 2  depicts a front view of the exemplary laptop or notebook computer of  FIG. 1  in a closed configuration. In this embodiment, the ALS  102  of  FIG. 1  may be located near the edge of the bezel surrounding the display. However, when the computer  200  is in the closed position, the ALS  102  of  FIG. 1  may no longer be able to detect ambient light. In such a position, the case of the computer  100  may block ambient light from reaching the ALS  102 . Therefore, to control the brightness of a set of indicator lights  204  located on the outer shell of the computer  200 , a second ambient light sensor  202  may be needed. This second ambient light sensor  202  may be positioned near the illuminator being controlled and facing the direction where the ambient light originates. In this position, ambient light sensor  202  may aid in controlling the indicator light brightness in response to detected ambient light. 
     FIG. 3   a  depicts an isometric view of a first embodiment illustrating an exemplary laptop or notebook computer in a closed configuration with a translucent window providing a path for present ambient light to reach an ambient light sensor. In  FIG. 3   a , a notebook or laptop computer  300  is shown in the closed position. An ALS  302  may be located near the front edge of the computer  300 . The ALS  302  may be utilized to control the brightness of the various illuminators of the computer  300 . For example, the ALS  302  may control the brightness of the display of the computer  300  when the computer is in the open position. The ALS  302  may also control the indicator lights  304  located on the outer edge of the computer  300 . For the ALS  302  to accurately control the brightness of the illuminators in response to ambient light, the ALS  302  may be positioned in such a manner as to allow the ALS  302  to detect ambient light in both the open and closed positions. To further facilitate the capability of the ALS  302  to detect ambient light when the computer  300  is in the closed position, a translucent window  306  may surround the ALS  302  to provide a path for ambient light to reach the ALS  302 . 
   The translucent window  306  of  FIG. 3  may be box-like in shape and surround the ALS  302 . The translucent window  306  may further abut the front edge of the computer  300  and extend away from the front edge. The translucent window  306  may thus form a see-through box that surrounds the ALS  302  and exposes the ALS  302  to ambient light. Because the translucent window  306  may be made from a translucent or clear material, ambient light may enter the translucent window  306  such that the ALS  302  may detect ambient light. By providing a path for ambient light to reach the ALS  302 , the ALS  302  may control the illuminators of the computer  300  when the computer is in both the open and closed configurations. 
   However, as discussed above, the optimal position for an ALS is typically near the illuminator being controlled and facing the same direction as the illuminator. When the embodiment depicted in  FIG. 3   a  is in the open position, the ALS  302  faces the user. However, when the embodiment depicted in  FIG. 3  is in the closed position, the ALS  302  faces the bottom half of the computer  300 . Therefore, the ALS  302  may not be located in the optimal position to detect and aid in the control of the indicator lights  304  of the computer  300 . Because less ambient light may reach the ALS  302  when the computer  300  is in the closed position, the sensitivity of the ALS  302  may be adjusted to account for the less-than-optimal position of the ALS  302 . The adjustment of the sensitivity of the ALS  302  may be explained in more detail below in  FIG. 6 . 
   As stated above, the translucent window  306  may surround the ALS  302  to provide a path for ambient light to reach the ALS  302  when the computer  300  is in the closed position. However, it is not required that the translucent window  306  surround the ALS  302 . The translucent window  306  may be constructed in any manner that allows ambient light to reach the ALS  302  such that the ALS  302  can detect ambient light when the computer  300  is both open and closed. For example, the translucent window  306  may be constructed as a series of reflectors that reflect ambient light to the ALS  302 . Further, the translucent window  306  may be constructed of any material that would allow ambient light to pass through the window, including, but not limited to, a clear plastic or glass. In general, the translucent window  306  may be constructed in such a way and of such a material that a path is provided for ambient light to reach the ALS  302 , such that the ALS  302  may detect ambient light. 
     FIG. 3   b  depicts a cross-section view of a second embodiment illustrating an exemplary laptop or notebook computer in a closed configuration with a light pipe or wave guide providing a path for ambient light to reach an ambient light sensor. In  FIG. 3   b , a notebook or laptop computer  350  is shown in the closed position. An ALS  352  may be located near the front edge of the computer  350 . The ALS  352  may be utilized to control the brightness of the various illuminators of the computer  350 . To facilitate the capability of a single ALS  352  to detect ambient light when the computer  350  is in the closed position, a light pipe  354  may provide a path for ambient light to reach the ALS  352 . 
   A light pipe, or wave guide, is a pipe or tube that transports light to another location with minimal light loss. In  FIG. 3   b , the light pipe  354  may be located within the bottom piece  356  of the computer  350  abutting the front edge of the computer  350  case. The light pipe  354  may extend horizontally away from the front edge of the computer  350 . The light pipe  354  may also bend 90 degrees and extend vertically, terminating directly below the ALS  352 . It should be noted that the angle or bend in the light pipe may vary in alternative embodiments and may be any angle necessary to transmit at least some light to the ALS. The light pipe  354  may be constructed of any material that propagates ambient light with minimal loss, such as a fiber optic cable. For example, the light pipe  354  may be constructed of optical fiber or an optical lighting film. In this embodiment, ambient light may enter the light pipe  354  at the front of the computer  350  and exit the light pipe directly below the ALS  352 , providing a path for ambient light to reach the ALS  352  when the computer  350  is in the closed position. Because a path for ambient light to reach the ALS  352  when the computer is in the closed position is provided, the ALS  352  may more accurately detect ambient light and therefore facilitate controlling the illuminators of the computer  350  when the computer is in both the open and closed configurations. 
   Similar to the embodiment depicted in  FIG. 3   a , when this embodiment is in the closed position, the ALS  354  may detect less ambient light than may be detected by the ALS when the embodiment is in an open position. Therefore, the sensitivity of the ALS  354  may be adjusted to account for the possibility that the ALS  354  may be detecting less ambient light. The adjustment of the sensitivity of the ALS  354  may be explained in more detail below in  FIG. 6 . 
     FIG. 4  depicts an isometric view of a third embodiment illustrating an exemplary laptop or notebook computer in a closed configuration with spacers providing a path for present ambient light to reach an ambient light sensor. In the embodiment depicted, a notebook or laptop computer  400  is shown in the closed position. Also depicted is a series of spacers  402  located between the top piece  404  and the bottom piece  406  of the computer  400 . 
   Similar to the embodiment of  FIG. 1 , the present embodiment may include an ALS  410  located on the bezel surrounding the display of computer  400 . However, because the computer  400  is depicted in the closed position, the ALS  410  located on the bezel surrounding the display is shown in phantom. Nonetheless, the ALS  410  may be utilized to control the brightness of the illuminators of the computer  400 . For example, similar to the embodiment shown in  FIG. 1 , the ALS  410  may control the brightness of the display of the computer  400  when the computer is in the open position. The ALS  410  may also control indicator lights  408  located on the outer edge of the computer  400 . For the ALS  410  to accurately control the brightness of the illuminators in response to the present ambient light, the ALS  410  may be positioned to allow the ALS  410  to detect ambient light in both the open and closed positions. To further facilitate the capability of the ALS  410  to detect ambient light when the computer  400  is in the closed position, spacers  402  may be provided to bias the computer  400  slightly open, thereby allowing at least some ambient light to reach the ALS  410 . To bias the computer  400  slightly open, spacers  402  may placed between the top piece  404  of the computer and the bottom piece  406  in such a way as to prevent computer  400  from fully closing. Additionally, in some embodiments a mirrored or reflective element may be provided on a surface opposing the ALS when the computer is in the closed position. Such a reflective element may allow more ambient light to reach the ALS by reflecting light entering through the gap defined by the spacer(s) at or into the ALS. 
   As stated above, spacers  402  may be provided to bias the computer  400  slightly open to allow ambient light to reach the ALS  410 . The spacers  402  are depicted in  FIG. 4  as being located between the top piece  404  and the bottom piece  406  of the computer  400  at the corners and above the indicator lights  408 . However, the spacers  402  may be located anywhere between the top piece  404  and the bottom piece  406  of the computer  400 . For example, the spacers  402  may be located near the hinges of the computer  400 . Further, the spacers  402  may be affixed to either the top piece  404  or the bottom piece  406  of the computer  400 , or some spacers may be affixed to the top piece  404  while other spacers are affixed to the bottom piece  406 . Generally, the spacers  402  may take any form that biases the top piece  404  and the bottom piece  406  of the computer  400  in a slightly open position such that an ALS located on the computer is capable of detecting ambient light in both the open and closed positions. In the embodiment depicted in  FIG. 4 , the spacers  402  may be plastic or rubber box-like structures placed between the top piece  404  and the bottom piece  406 . However, as mentioned above, the spacers  402  may be constructed of any material and be of any shape such that the spacers bias the computer  400  in a slightly open position. By biasing the computer  400  in a slightly open position, ambient light may be allowed to enter the computer  400  between the top piece  404  and the bottom piece  406  and may be detected by an ALS. 
   Similar to the embodiment depicted in  FIG. 3 , when this embodiment is in the closed position, the ALS  410  faces the bottom piece  406  of the computer  400 . Therefore, the ALS  410  is not located in the optimal position to detect and aid in the control of the indicator lights  404  of the computer  400 . Because less ambient light may reach the ALS  410  when the computer  400  is in the closed position, the sensitivity of the ALS  410  may be adjusted to account for the less-than-optimal position of the ALS  410 . The adjustment of the sensitivity of the ALS  410  may be explained in more detail below in  FIG. 6 . 
     FIG. 5  depicts a side view of a fourth embodiment taking the form of a computer design. The present embodiment allows at least some ambient light to reach an ambient light sensor when the laptop is in both an open and closed position. In the embodiment depicted, a notebook or laptop computer  500  is shown in the closed position. An ALS  502  may be located such that it may be utilized to control the brightness of the illuminators of the computer  500 . For example, the ALS  502  may control the brightness of the display of the computer  500  when the computer is in the open position. The ALS  502  may also control indicator lights located on the outer edge of the computer  500 . For the ALS  502  to more accurately control the brightness of the illuminators in response to the ambient light detected, the ALS  502  may be positioned in such a manner as to allow the ALS  502  to detect the present ambient light in both the open and closed positions. To further facilitate the capability of the ALS  502  to detect ambient light when the computer  500  is in the closed position, the computer  500  may be constructed in such a manner as to provide a path for ambient light to reach the ALS  502 . 
   For example and as depicted in  FIG. 5 , the computer  500  may be constructed in a clamshell shape. At the front end of computer  500 , a notch  504  may be cut into the clamshell such that, at one end of the clamshell, the top piece  506  of the computer  500  and the bottom piece  508  do not come into contact. Further, the ALS  502  may be positioned on the top piece  506  within the notch  504 . Through the design of the computer  500 , the ALS  502  may detect ambient light when the computer  500  is in both the open position and the closed position. In this manner, the ALS  502  may control multiple illuminators located on the computer  500  as well as on the outer shell of the computer  500 . 
   Similar to the embodiments depicted in  FIGS. 3 and 4 , the sensitivity of the ALS  502  may be adjusted to account for the lesser amount of ambient light that may reach the ALS  502  when the computer is in the closed position. The adjustment of the sensitivity of the ALS  502  may be further explained in more detail below in  FIG. 6 . 
   As discussed in  FIGS. 1-5 , a single ambient light sensor may be provided that controls the brightness of several illuminators of a computer or other electronic device. The ALS may control the illuminators when the electronic device is in both the open and closed positions. However, as explained above, certain configurations allow less ambient light to reach the ALS when the electronic device is in the closed position than when the device is in the open position. Thus, a single ALS may detect less ambient light when the computer is in the closed position when compared to the open position, even though the ambient light of the surrounding area may not have changed. In such circumstances, the sensitivity of the ALS may be adjusted to account for the less ambient light detected by the ALS. 
     FIG. 6  is a flow chart a fifth embodiment for adjusting the sensitivity of an ambient light sensor when an electronic device is in a closed position. In operation  600 , the electronic device may monitor to detect which position the device is in. If the embodiment determines that the electronic device is in the closed position, the sensitivity of the ALS may need to be adjusted to account for the less amount of ambient light reaching the ALS. 
   If the embodiment determines that the lid of the electronic device is in the closed position in operation  600 , the sensitivity of the ALS may be adjusted in operation  602 . To account for the lesser amount of ambient light reaching the ALS in the closed position, the output of the ALS may be adjusted to increase the sensitivity of the sensor. As described above, an ALS located on the inner face of an electronic device may detect less ambient light when the device is in the closed position when compared to the open position, even though the ambient light in the surrounding area may not have changed. Thus, the sensitivity of the ALS may be increased accordingly. 
   To adjust the sensitivity of the ALS, one embodiment may simply adjust the output of the ALS. For example, an ALS may aid in adjusting the brightness of an illuminator of an electronic device in response to ambient light. One method of controlling the brightness of an illuminator is to accept the output provided by the ALS and adjust the brightness accordingly. For example, an ALS output ranging from 0-100 units on an arbitrary scale may correspond to a range from no ambient light to direct sunlight. (It should be noted that the range of the arbitrary scale is likewise arbitrary; 0-100 is used solely for convenience.) Thus, the higher the output from ALS, the brighter the illuminator may become. In this configuration, a control circuit of an electronic device may control the brightness of an illuminator based on the ambient light output provided by the ALS. Thus, the control circuit may increase the brightness of an illuminator when the output of the ALS increases. Further, the control circuit may only adjust the brightness of the illuminator for certain intervals of ambient light. For example, the control circuit may only increase the brightness of the illuminator for every 10 units of the arbitrary scale outputted by the ALS. Thus, the brightness of the illuminator may be adjusted when the ALS output reads 10 units, 20 units, 30 units, etc. 
   When the electronic device is in the closed position, however, the output of the ALS may only range from 0-20 units (indicating no ambient light to direct sunlight) as less ambient light may reach the sensor in this position. Therefore, the sensitivity of the ALS may be adjusted accordingly. In this example, the intervals in which the brightness of the illuminator is adjusted based on the ambient light may be modified. Thus, instead of adjusting the brightness for every 10 units output by the ALS, the control circuit may adjust the brightness for every 2 units output by the ALS. In this manner, the sensitivity of the ALS may be increased to account for the lesser amount of ambient light reaching the ALS. Further, by adjusting the sensitivity of the ALS, a single ALS may more accurately control the brightness of illuminators located on both the inside and outside of the electronic device. 
   As an alternative, the output of the ALS may be multiplied by a scaling factor to compensate for the reduced ambient light reaching the ALS under certain operating conditions, such as when a lid or top of the computer is closed. In such an embodiment, the intervals, range or outputs of the arbitrary scale that correspond to the brightness levels of the indicator(s) are unchanged. Instead, the embodiment applies the scaling factor to the ALS output to produce a modified output within the same range as a standard, unmodified output. 
   As one example, presume the ALS may sense or receive only one-fifth as much light when the computer is closed as it may receive when the computer is open. The embodiment may therefore multiply the ALS output by five to produce a modified output falling within the same ranges expected when the computer is open. In this manner, a single scale or range may be used for control of the illuminators. It should be noted that the scaling factor may be empirically determined and need not be linear. The scaling factor may be logarithmic or otherwise change as the ALS output increases or decreases. 
   As another alternative, the sensitivity of the ALS may be adjusted by adjusting the gain of the sensor. By adjusting the gain of the ALS, the sensor may become more sensitive to smaller external changes in the brightness of the ambient light when the device is in the closed position. Thus, adjusting the gain of the sensor may account for the lesser amount of ambient light that may be detected by the ALS in the closed position. 
   The sensitivity of the ALS may remain adjusted until the embodiment determines that the lid of the electronic device is opened in operation  604 . In this circumstance, the ALS may not need to be adjusted as it may be assumed that the ALS is receiving the ambient light indicative of the ambient light in the surrounding area. Thus, once the embodiment determines that the electronic device is in the open position, the sensitivity of the ALS may be adjusted back to the normal state in operation  606 . When the ALS is normalized in this fashion, the output of the ALS may be no longer adjusted as it is assumed that the ALS is receiving direct ambient light. Referring to the previous example, in the normal state (or when the electronic device is in the open position), the ALS output would return to a range of 0-100 units and typically would no longer be adjusted by the embodiment. The above process may be repeated as the lid of the electronic device is opened and closed during use, thereby adjusting the sensitivity of the ALS accordingly, e.g., the return arrow from operation  606  to operation  600 . 
     FIG. 7  depicts a block diagram of an apparatus to control the brightness of an illuminator based on ambient light. An ALS  700  may detect ambient light  706  of a surrounding area. The ALS  700  may output the detected ambient light level to a control circuit  702 . The control circuit  702  may then control the brightness of an illuminator  704  based on the ambient light level output received from the ALS  700 . In this manner, the brightness of the illuminator  704  may be adjusted in response to the ambient light  706  in the surrounding area so that the illuminator may provide a uniform appearance under all lighting conditions. 
   The control circuit  702  may be formed by hardware components or may be embodied in a general-purpose or special-purpose processor, or logic circuits programmed with machine-executable instructions, to perform the controlling of the illuminator  704 . Further, control circuit  702  may be embodied within an electronic device also containing the ALS  700  and the illuminator  704 . 
   It should be noted that the flowchart of  FIG. 6  is illustrative only. Alternative embodiments of the present invention may add operations, omit operations, or change the order of operations without affecting the spirit and scope of the present invention. 
   The foregoing merely illustrates certain principles and embodiments of the invention. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements and methods which, although not explicitly shown or described herein, embody the principles of the invention and are thus within the spirit and scope of the present invention. As one example, in alternative embodiments the output of the ALS may be scaled downward when the computer is in the open position and the ALS output when the computer is closed may be used as a baseline. As yet another example, the sensitivity of the ALS may likewise be adjusted downward when the computer is in the open position, instead of such functions occurring when the computer is closed. From the above description and drawings, it will be understood by those of ordinary skill in the art that the particular embodiments shown and described are for purposes of illustrations only and are not intended to limit the scope of the present invention. References to details of particular embodiments are not intended to limit the scope of the invention.

Metadata:
Filing Date: 20080521
Publication Date: 20100706
Grant Date: 20100706
Priority Date: 20080521
Inventors: MAHOWALD PETER H.
MARTINEZ JOSE N.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F1/3265", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y02D10/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/3265", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/3203", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/3203", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y02D10/00", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 41341383