Abstract:
An improved organic electroluminescent display includes a plurality of normal mode colors and a plurality of user-selected power saving mode colors. The display is switchable between a normal display mode and a power saving display mode. In the normal display mode, the normal mode colors are displayed by the display. Conversely, in the power saving display mode, the power saving mode colors are displayed by the display.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
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   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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   INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
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   NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION 
   A portion of the material in this patent document is subject to copyright protection under the copyright laws of the United States and of other countries. The owner of the copyright rights has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office publicly available file or records, but otherwise reserves all copyright rights whatsoever. The copyright owner does not hereby waive any of its rights to have this patent document maintained in secrecy, including without limitation its rights pursuant to 37 C.F.R. § 1.14. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention pertains generally to organic electroluminescent displays, and more particularly to methods for conserving power consumed by organic electroluminescent displays. 
   2. Description of Related Art 
   Liquid crystal displays (LCDS) are widely used for portable computers and other products. One major disadvantage of an LCD is that an LCD emits no light; only the transparency of an LCD changes by adding or not adding a voltage. To obtain a high contrast, an LCD requires a backlight. Unfortunately, a backlight lamp consumes much power, e.g., more than one-half of the total power that a laptop personal computer (PC) consumes. The power consumption of the LCDs is an important matter for battery operated portable products. 
   Current state-of-the art displays include organic electroluminescent (OEL) displays. OEL displays are slowly being introduced into the electronics market. Unlike LCDs, each pixel on an OEL display emits light. Therefore, a backlight is not required. Further, OEL displays can be slimmer than LCDs. It is likely that in many applications LCDs will be replaced with OEL displays in the near future. 
   As stated above, OEL displays emit light. It happens that darker colors consume less power than brighter colors. As such, darker colors are preferable for power saving. However, white, or other brighter colors, are commonly used as background colors for windows in a PC, and these colors increase the power consumption of OEL displays. Accordingly, if brighter colors occupy most areas of the display screen, a color reverse might be good in order conserve power consumption. Microsoft Windows OS, for example, has such a color reverse feature. A user can change the display mode in a display appearance window. Unfortunately, this feature can only be applied to Windows graphic objects; that is, window background, frames, menus, etc. Many web pages use white as a background color, but this background color remains the same regardless of user Windows settings. Therefore, the Windows color reverse feature is not beneficial for power conservation. In order to maximize power conservation, all brighter colors on the display screen should be changed to darker ones. 
   The present invention recognizes the present drawbacks and provides a solution to one or more of the problems associated therewith. 
   BRIEF SUMMARY OF THE INVENTION 
   An aspect of the invention is to provide a self-emitting display such as an organic electroluminescent display that includes a plurality of normal mode colors and a plurality of power saving mode colors. Each power saving mode color is assigned to a normal mode color. During a power saving display mode, each normal mode color having an assigned power saving mode color is switched to the assigned power saving mode color. 
   In a preferred embodiment, each normal mode color not having an assigned power saving mode color is reversed during a power saving display mode. Moreover, a user can assign each power saving mode color to a normal mode color. Preferably, the display includes a power saving indicator that shows the reduction in energy consumed by the display when it is in the power saving display mode. The power saving display mode can be entered manually or automatically. In a preferred embodiment, the display is an organic electroluminescent display. 
   Another aspect of the invention is a method for conserving power in an organic electroluminescent display. The method includes providing a plurality of normal mode colors and providing a plurality of power saving mode colors. Each power saving mode color is assigned to a normal mode color. In a power saving display mode, each normal mode color having an assigned power saving mode color is switched to the assigned power saving mode color. 
   A still further aspect of the invention is an organic electroluminescent display having a plurality of plural normal mode colors and a plurality of power saving mode colors. In this aspect of the present invention, the display is switchable between a normal display mode, in which the normal mode colors are displayed, and a power saving display mode, in which the power saving mode colors are displayed. 
   Further aspects of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
     The invention will be more fully understood by reference to the following drawings which are for illustrative purposes only: 
       FIG. 1  is a block diagram of an organic electroluminescent display system. 
       FIG. 2  is a flow chart of the configuration logic according to the present invention. 
       FIG. 3  is a view of a color configuration window according to the present invention. 
       FIG. 4  is a color selection window according to the present invention. 
       FIG. 5  is a flow chart of the operating logic according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring more specifically to the drawings, for illustrative purposes the present invention is embodied in the apparatus generally shown in  FIG. 1  through  FIG. 5 . It will be appreciated that the apparatus may vary as to configuration and as to details of the parts, and that the method may vary as to the specific steps and sequence, without departing from the basic concepts as disclosed herein. 
   Referring initially to  FIG. 1 , an organic electroluminescent display system is shown and is generally designated  10 . As shown, the system  10  includes a display  12 , such as an organic electroluminescent (OEL) display, to which a power supply  14  is connected. It can be appreciated that the power supply  14  can be an alternating current (AC) power supply or a direct current (DC) power supply. Moreover, a processor  16  is connected to the display  12 . The processor  16  includes a program, described below, that can be used to conserve the power consumed by the display  12  during operation.  FIG. 1  further shows a user interface  18  that is connected to the processor  16 . The user interface  18  can be, for example, a keyboard, a mouse, an electric pen, etc. In lieu of a user interface  18 , the display  12  can include touch screen functionality that can act as a user interface.  FIG. 1  further shows that the system  10  further includes a power saving indicator  20  that can appear on the display  12  in order to show the reduction in energy consumption of the display  12  when it is in the power saving display mode, described in detail below. 
   It is to be understood that the processor  16  includes a program that provides a power saving display mode for the display  12 . The program, described below, increases the energy efficiency of the display  12  while maintaining the clarity of the display. In other words, the easiest way to convert bright colors to dark colors is to automatically reverse the colors. However, this results in a bizarre display scheme, i.e., it looks like a photo negative, that is difficult to see. Additionally, the background color can be user selected and it may be darker in normal mode. Thus, when reversed, the background color is going to be brighter. The program according to the present invention allows a user to freely assign a power saving display mode color to each normal mode color and when the power saving display mode is executed each normal mode color is changed to its corresponding power saving display mode color. 
   Referring now to  FIG. 2 , configuration logic according to the present invention is shown and commences at block  50  with a do loop, wherein when a button, e.g., a color configuration button, is toggled, the following steps are performed. At block  52 , a color configuration window is displayed. Thereafter, at block  54 , a menu of normal mode colors is provided, e.g., within the color configuration window. Moving to block  56 , a menu of power saving mode colors is also provided, e.g., within the color configuration window. Proceeding to block  58 , a user is allowed to select one or more normal mode colors for each element displayed on the display  12  ( FIG. 1 ). At block  60 , a user is allowed to select a power saving mode color for each normal mode color. The logic then ends at state  62 . 
     FIG. 3  shows a non-limiting, exemplary embodiment of a color configuration window, generally designated  100 . As shown, the color configuration window  100  includes a normal mode column  102  that includes a first color indication square  104 , a second color indication square  106 , a third color indication square  108 , and a fourth color indication square  110 . The color configuration window  112  also includes a power saving mode column  112  that includes a first color indication square  114 , a second color indication square  116 , a third color indication square  118 , and a fourth color indication square  120 . 
   It is to be understood that in a non-limiting, exemplary embodiment, user can select a normal mode color for a particular element displayed on the display  12  ( FIG. 1 ) by using the user interface  18 , e.g., a mouse, to move a cursor to a particular color area or color element on the display  12 . Then, the user can drag-and-drop that particular color area or color element into a color indication square  104 ,  106 ,  108 ,  110  in the normal mode column  102 , e.g., the first color indication square  104 . After that, the user can toggle or otherwise click on the corresponding first color indication square  114  in the power saving mode column  112  to open a color selection window, e.g., the color selection window shown described below in conjunction with  FIG. 4 . Using the color selection window, the user can select a power saving mode color for the corresponding normal mode color shown in the first color indication square  104 . Similarly, the user can drag-and-drop other colors into the second and third color indication squares  106 ,  108  in the normal mode column  102  and choose corresponding power saving mode colors for each normal mode color via the color selection window. 
   It can be appreciated that more than four color indication squares  104 ,  106 ,  108 ,  110  can be included in the normal mode column  102  and as such, the power saving mode column  112  can include more than four color indication squares  114 ,  116 ,  118 ,  120 . Moreover, it can be appreciated that the color configuration window  100  can include names of particular graphic objects, e.g., desktop, scrollbar, background, etc., adjacent to corresponding color indication squares  104 ,  106 ,  108 ,  110  in the normal mode column  102 . In such an embodiment, a user does not have to drag-and-drop each object color—he or she can simply select a normal mode color and a power saving mode color for each graphic object listed in the color configuration window  100 . 
   Further, it is to be understood that the fourth color indication square  110  in the normal mode column  102  and the corresponding fourth color indication square  120  in the power saving mode column  112  can be a “catch-all” configuration setting for all other remaining colors not given a corresponding power saving mode color. For example, by selecting an original colors square  122  all other normal mode colors not assigned a power saving mode color can remain their original color during the power saving mode. On the other hand, if a reversed colors square  124  is selected, the other colors not assigned a power saving mode color can be reversed during the power saving mode. 
     FIG. 4  shows a color selection window, generally designated  150 . As shown in  FIG. 4 , the color selection window  150  includes a basic colors menu  152  and a custom colors menu  154  from which a user can select power saving mode colors as described above. 
   Referring to  FIG. 5 , a non-limiting, exemplary embodiment of the operating logic according to the present invention is shown and commences at block  200  with a do loop, wherein during operation, the succeeding steps are performed. At block  202 , the normal mode colors are displayed at the display  12  ( FIG. 1 ). Next, at decision diamond  204 , it is determined whether a power saving display mode is selected. The power saving display mode can be selected manually by a user. Alternatively, the power saving display mode can be selected automatically, e.g., when the power supply  14  ( FIG. 1 ) is switched from AC to DC or if the power level within the power supply  14  ( FIG. 1 ) has fallen below a minimum power threshold. 
   If the power saving mode is not selected, the logic returns to block  202  and the normal mode colors continue to be displayed by the display  12 . Otherwise, if the power saving mode is selected, the logic proceeds to block  206  and the power saving mode colors previously selected by a user are displayed. Additionally, the normal mode colors that are not assigned power saving mode colors, are simply reversed or remain their original colors. Thereafter, moving to decision diamond  208 , it is determined whether a normal display mode has been selected, e.g., threshold or manually. If so, the logic returns to block  202  and the normal mode colors are again displayed. The logic then continues as described above. If the normal display mode is not selected, the logic returns to block  206  and the power saving mode colors continue to be displayed. 
   It is to be understood that a graphic memory within the processor usually stores three (Red, Green, Blue) 8-bit data per pixel. The screen on the display  12  is drawn based on the graphics data within the graphic memory. With the system and method described above, a user can select a power saving mode color for one or more normal mode colors. During operation, when a power saving mode is entered, the normal mode colors are switched to their corresponding power saving mode colors. Specifically, each of the pixel data is replaced with a new value based on the color conversion information that a user inputs in the color configuration window  100  ( FIG. 3 ). 
   Thereafter, when the normal mode is entered, the power saving mode colors revert back to the normal mode colors. Accordingly, a user can effectively choose which normal mode colors are to be switched during power saving mode in order to effectively conserve power while maintaining screen clarity on the display  12  ( FIG. 1 ). It can be appreciated that the power saving display mode can be used in conjunction with displays other than OEL displays. Moreover, the display  12  ( FIG. 1 ) can be used in conjunction with a computer, a cellular telephone, a personal data assistant (PDA), or any other energy-sensitive device that includes a display. 
   Although the description above contains many details, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural, chemical, and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.”