Patent Publication Number: US-2012026106-A1

Title: Electronic paper display

Description:
RELATED APPLICATIONS 
     This application claims priority to Taiwan Application Serial Number 99125442, filed Jul. 30, 2010, which is herein incorporated by reference. 
     BACKGROUND 
     1. Field of Invention 
     The present invention relates generally to a display panel and, more particularly, to an electronic paper panel. 
     2. Description of Related Art 
     With advances in electronic technology, various electronic products, such as computers, televisions, mobile phones, etc., have been introduced into the market to meet the consumers&#39; daily demands. E-readers have recently been developed to help meet user demands, as well as in response to the awareness of environmental protection. 
     Conventional e-readers rely on environmental light sources, such as natural light, lamp-light, etc., to illuminate the electronic paper of the e-readers so that the users may see the contents displayed thereon. In the case where the environmental light sources are insufficient to illuminate the electronic paper (for example, when the user is sitting in a bus at night or a dim outdoor space), users cannot read the contents on the e-readers. 
     In sum, due to the nature of conventional electronic paper, conventional e-readers must rely on the environmental light sources to display the contents of the e-readers. As such, users cannot utilize the e-readers when the environmental lights are insufficient, and this can cause inconveniences to the users. Accordingly, there exists an urgent need in the related art to provide a solution to address this disadvantage. 
     SUMMARY 
     The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the present invention or delineate the scope of the present invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later. 
     An electronic paper display is provided to address or alleviate the conventional problems described hereinabove. Specifically, the electronic paper display provided herein may display the contents therein under dim light or in the absence of environmental light. 
     To this end, in one aspect, the present invention is directed to an electronic paper display comprising an electronic paper panel, a light-guiding structure, and a light source. The light-guiding structure is disposed above the electronic paper panel, and the light source is disposed on one lateral side of the light-guiding structure. The light-guiding structure is configured to reflect and scatter the light provided by the light source. And the light, after being reflected and scattered by the light-guiding structure, may illuminate the electronic paper panel. 
     In another aspect, the present invention is directed to an electronic paper display comprising an electronic paper panel and an organic light-emitting diode layer disposed above the electronic paper panel. The organic light-emitting diode layer is an active light source that provides light for the electronic paper panel. 
     In view of the foregoing, some embodiments of the present invention provide an electronic paper display having a light source and a light-guiding structure so that the light provided by the light source may be reflected and scattered by the light-guiding structure and then illuminate the electronic paper panel. Alternatively, some embodiments of the present invention provide an electronic paper display having an organic light-emitting diode layer as an active light source so that the light provided by the organic light-emitting diode layer illuminates the electronic paper panel. As such, users may read the contents of the e-readers using the electronic paper display according to embodiments of the present invention, even under dim light or in the absence of environmental light. 
     It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows: 
         FIG. 1  is a schematic diagram illustrating an electronic paper display according to the first embodiment of the present invention; 
         FIG. 2  is a schematic diagram illustrating an electronic paper display according to the second embodiment of the present invention; 
         FIG. 3  is a schematic diagram illustrating an electronic paper display according to the third embodiment of the present invention; 
         FIG. 4  is a schematic diagram illustrating an electronic paper display according to the forth embodiment of the present invention; 
         FIG. 5  is a schematic diagram illustrating an electronic paper display icy according to the fifth embodiment of the present invention; 
         FIG. 6  is a schematic diagram illustrating an electronic paper display according to the sixth embodiment of the present invention; 
         FIG. 7  is a schematic diagram illustrating an electronic paper display according to the seventh embodiment of the present invention; and 
         FIG. 8  is a schematic diagram illustrating an electronic paper display according to the eighth embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utilized. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples. 
     The terms used in this specification generally have their ordinary meanings in the art, within the context of the disclosure, and in the specific context where each term is used. Certain terms that are used to describe the disclosure are discussed below, or elsewhere in the specification, to provide additional guidance to the practitioner regarding the description of the disclosure. The use of examples anywhere in this specification, including examples of any terms discussed herein, is illustrative only, and in no way limits the scope and meaning of the disclosure or of any exemplified term. Likewise, the disclosure is not limited to various embodiments given in this specification. 
     As used in the description herein and throughout the claims that follow, the meaning of “a”, “an”, and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. 
     As used herein, the terms “comprising,” “including,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. 
     Electronic paper panels, which are commonly employed in conventional e-readers, are reflective panels. Accordingly, such e-readers rely on environmental light sources, and users cannot read/view the contents when the e-readers are in dim light conditions or present in the absence of environmental light. 
     Since users may still need to use the e-readers in the absence of environmental light, conventional e-readers are, at times, provided with lateral light sources to illuminate the electronic paper panel. However, by using only the conventional lateral light sources, the e-readers may suffer from uneven distribution of light across the electronic paper panel. Further, more light-emitting diodes may be required due to the unevenness of light, and it in turns causes more power consumption. In view of the foregoing, providing only the lateral light sources in the electronic paper panel would result in the rise of the manufacturing cost and power consumption but still be unable to provide satisfactory reading conditions for the users. 
     Therefore, electronic paper displays according to embodiments of the present invention are provided here to address or alleviate the problems faced by the conventional electronic paper display. 
     In one aspect, the present invention is directed to an electronic paper display comprising an electronic paper panel, a light-guiding structure, and a light source. The light-guiding structure is disposed above the electronic paper panel, and the light source is disposed on one lateral side of the light-guiding structure. The light-guiding structure is configured to reflect and scatter the light provided by the light source. And the light, after being reflected and scattered by the light-guiding structure, may illuminate the electronic paper panel. As such, the electronic paper display according to this aspect may display the contents therein under dim light or in the absence of environmental light. Some exemplary embodiments of such electronic paper display are discussed herein below. 
     Reference is now made to  FIG. 1  which is a schematic diagram illustrating an electronic paper display  100  according to the first embodiment of the present invention. As shown in the figure, the electronic paper display  100  includes a light-guiding structure  110 , an electronic paper panel  120 , a system  130 , a light source  140  and a diffusion sheet  150 . 
     The light-guiding structure  110  is disposed above the upper surface of the electronic paper panel  120 . As sued herein, the upper surface of any sheets/layers described herein is referred to as the surface that faces the user during use, whereas a lower surface is the one opposite to the upper surface. Also, each sheet/layer may have at least one lateral side in addition to the upper and lower surfaces. 
     The light source  140  is disposed on one lateral side of the light-guiding structure  110 , and the diffusion sheet  150  is disposed between the light source  140  and the light-guiding structure  110 . The light source  140  is operable to irradiate light, and the diffusion sheet  150  is configured to diffuse the light from the light source  140  so as to provide a more uniform light for the light-guiding structure  110 . The light-guiding structure  110  is arranged in such a way to receive the diffused light from the diffusion sheet  150  and is operable to reflect and scatter the incident light so that the light may illuminate the electronic paper panel  120 . The path of the light in the electronic paper display is shown as arrow A in  FIG. 1  to  FIG. 8 . 
     According to the principles and spirit of the present invention, the upper surface of the light-guiding structure  110  is treated so that it may exhibit the reflecting and scattering functionalities. For example, the upper surface may be printed with reflective inks, etched with chemicals or lasers, or molded to form structures or microstructures, thereby providing the light-guiding structure  110  with the optical characteristics of a light guide plate. As such, the light-guiding structure  110  provided herein is operable to reflect and scatter the light irradiated by the light source  140  so that the light may illuminate the electronic paper panel  120 . 
     In the embodiments of the present invention, the electronic paper panel  120  may be any reflective panel suitable for use in the e-readers. Illustrative examples of the electronic paper panel  120  include, but are not limited to, electrophoretic display panels and cholesterol liquid crystal display panels. 
     Generally, the system  130  may include at least one driving circuits, such as the driving circuit(s) for the electronic paper panel  120  and the driving circuit(s) for the light source  140 . 
     As can be appreciated by those with ordinary skill in the art, the light source  140  may include a device for irradiating light, and the device is electrically connected to a power supply. Illustrative examples of the device for irradiating light include, but are not limited to, a cathode fluorescent lamp (“CCFL”), an external electrode fluorescent lamp (“EEFL”), and a light emitting diode (“LED”). 
     Illustrative materials suitable for use as the diffusion sheet  150  are acrylic resins with a variety of diffusive particles, such as titanium dioxide, silicon dioxide, and silicon. 
       FIG. 2  is a schematic diagram illustrating an electronic paper display  200  according to the second embodiment of the present invention. 
     Generally, the electronic paper display  200  includes a light-guiding structure  210 , an electronic paper panel  220 , a system  230 , a light source  240  a diffusion sheet  250 , and a touch panel  260 . The electronic paper display  200  and the electronic paper display  100  described hereinabove in connection with  FIG. 1  are substantially similar in structure, except that the electronic paper display  200  further includes a touch panel  260  which is disposed between the electronic paper panel  220  and the light-guiding structure  210 . Accordingly detailed descriptions regarding the arrangements and examples of the elements of electronic paper display  200  are omitted herein for the sake of brevity. 
     Next, in  FIG. 3 , a schematic diagram of an electronic paper display  300  according to the third embodiment of the present invention is illustrated. 
     In this embodiment, the electronic paper display  300  comprises a touch panel  310 , an electronic paper panel  320 , a light source  330  and a diffusion sheet  340 . The electronic paper panel  320 , the light source  330  and the diffusion sheet  340  are substantially similar to those described hereinabove in connection with  FIG. 1 , and hence, detailed descriptions thereof are omitted herein for the sake of brevity and only the structure of the touch panel  310  is further described hereinafter. 
     AS shown in  FIG. 3 , the touch panel  310  is disposed above the upper surface of the electronic paper panel  320 . According to the principles and spirit of the present invention, the touch panel  310  may be a resistive touch panel and is operable to serve as a light-guiding structure for reflecting and scattering the light toward the electronic paper panel  320 . 
     For example, the touch panel  310  (in this case, a resistive touch panel) may comprise an upper substrate  311 , and the light source  330  and diffusion sheet  340  are disposed at one lateral side of the upper substrate  311 . The uppermost layer, such as a flexible plastic overlay, of a resistive touch panel may be used as the upper substrate  311  described herein, and the upper surface of the upper substrate  311  may be treated to so that it may exhibit the reflecting and scattering functionalities. For example, the upper surface may be printed with reflective inks, etched with chemicals or lasers, or molded to form structures or microstructures, thereby providing the light-guiding structure  311  with the optical characteristics of a light guide plate. As such, the upper substrate  311  provided herein is operable to reflect and scatter the light diffused by the diffusion sheet  340 , thereby illuminating the electronic paper panel  320 . 
     In practice, the touch panel  310  may further comprise an upper indium tin oxide (ITO) layer  312 , a plurality of dots  313 , a lower ITO layer  314 , and a lower substrate  315 . The upper ITO layer  312  is disposed on the lower surface of the upper substrate  311 , whereas the lower ITO layer  314  is disposed on the upper surface of the lower substrate  315 . The layer consisting of dots  313  is sandwiched between the upper ITO layer  312  and the lower ITO layer  314 . 
     For the sake of brevity, a system (such as the system  130  described hereinabove in connection with  FIG. 1 ) of the electronic paper display  300  is not shown in  FIG. 3 , and it will be clear to those of ordinary skill in the art that, such a system will necessarily be included in the electronic paper display  300 . 
       FIG. 4  is a schematic diagram illustrating an electronic paper display  400  according to the forth embodiment of the present invention. 
     In this embodiment, the electronic paper display  400  comprises a touch panel  410 , an electronic paper panel  420 , a light source  430 , a diffusion sheet  440 , and a system (not shown). The electronic paper panel  420 , the light source  430 , the diffusion sheet  440 , and the system are substantially similar to those described hereinabove in connection with  FIG. 1 , and hence, detailed descriptions thereof are omitted herein for the sake of brevity and only the structure of the touch panel  410  is further described hereinafter. 
     As shown in  FIG. 4 , the touch panel  410  is disposed above the upper surface of the electronic paper panel  420 . According to the principles and spirit of the present invention, the touch panel  410  may be a capacitive touch panel and is operable to serve as a light-guiding structure for reflecting and scattering the light toward the electronic paper panel  420 . 
     For example, the touch panel  410  (in this case, a capacitive touch panel) may comprise an upper substrate  411 , and the light source  430  and diffusion sheet  440  are disposed at one lateral side of the upper substrate  411 . The uppermost layer (such as a sensor glass/flexible print circuit sheet or a cover glass/flexible print circuit sheet) of a capacitive touch panel may be used as the upper substrate  411  described herein, and the upper surface of the upper substrate  411  may be treated to so that it may exhibit the reflecting and scattering functionalities. For example, the upper surface may be printed with reflective inks, etched with chemicals or lasers, or molded to form structures or microstructures, thereby providing the light-guiding structure  411  with the optical characteristics of a light guide plate. As such, the upper substrate  411  provided herein is operable to reflect and scatter the light diffused by the diffusion sheet  440 , thereby illuminating the electronic paper panel  420 . 
     In practice, the touch panel  410  may further comprise an upper ITO layer  412 , a pressure sensitive adhesive (PSA) layer  413 , a lower substrate  414 , and a lower ITO layer  415 . The upper ITO layer  412  is disposed on the lower surface of the upper substrate  411 , whereas the lower ITO layer  415  is disposed on the lower surface of the lower substrate  414 . The PSA layer  413  is sandwiched between and bonds together the upper ITO layer  412  and the lower substrate  414 . 
       FIG. 5  is a schematic diagram illustrating an electronic paper display  500  according to the fifth embodiment of the present invention. 
     In this embodiment, the electronic paper display  500  comprises a touch panel  510 , an electronic paper panel  520 , a light source  530 , a diffusion sheet  540 , and a system (not shown). The electronic paper panel  520 , the light source  530 , the diffusion sheet  540 , and the system are substantially similar to those described hereinabove in connection with  FIG. 1 , and hence, detailed descriptions thereof are omitted herein for the sake of brevity and only the structure of the touch panel  510  is further described hereinafter. 
     AS shown in  FIG. 5 , the touch panel  510  is disposed above the upper surface of the electronic paper panel  520 . According to the principles and spirit of the present invention, the touch panel  510  may be a capacitive touch panel and is operable to serve as a light-guiding structure for reflecting and scattering the light toward the electronic paper panel  520 . 
     For example, the touch panel  510  (in this case, a capacitive touch panel) may comprise an upper substrate  511 , and the light source  530  and diffusion sheet  540  are disposed at one lateral side of the upper substrate  511 . The uppermost layer (such as a protector sheet) of a capacitive touch panel may be used as the upper substrate  511  described herein, and the upper surface of the upper substrate  511  may be treated to so that it may exhibit the reflecting and scattering functionalities. For example, the upper surface may be printed with reflective inks, etched with chemicals or lasers, or molded to form structures or microstructures, thereby providing the light-guiding structure  511  with the optical characteristics of a light guide plate. As such, the upper substrate  511  provided herein is operable to reflect and scatter the light diffused by the diffusion sheet  540 , thereby illuminating the electronic paper panel  520 . 
     In practice, the touch panel  510  may further comprise a PSA layer  512 , an upper ITO layer  513 , a lower substrate  514 , and a lower ITO layer  515 . The upper ITO layer  513  is disposed on the upper surface of the lower substrate  514 , whereas the lower ITO layer  515  is disposed on the lower surface of the lower substrate  514 . The PSA layer  512  bonds the upper ITO layer  513  to the lower surface of the upper substrate  511 . 
     In another aspect, the present invention is directed to an electronic paper display comprising an electronic paper panel and an organic light-emitting diode layer disposed above the electronic paper panel. The organic light-emitting diode layer is an active light source that provides light for the electronic paper panel. As such, the electronic paper display provided herein may display the contents therein under dim light or in the absence of environmental light. Some exemplary embodiments of such electronic paper display are discussed herein below. 
     Reference is now made to  FIG. 6  which is a schematic diagram illustrating an electronic paper display  600  according to the sixth embodiment of the present invention. As shown in the figure, the electronic paper display  600  comprises an organic light-emitting diode layer  610 , an electronic paper panel  620  and a system  630 . 
     The organic light-emitting diode layer  610  is disposed above the electronic paper panel  620 . According to the principles and spirit of the present invention, the organic light-emitting diode layer  610  serves as an active light source for irradiating light that illuminate the electronic paper panel  620 . 
     The electronic paper panel  620  is substantially similar to those described hereinabove in connection with  FIG. 1 , and hence, detailed descriptions thereof are omitted herein for the sake of brevity. 
     Similar to system  130  described hereinabove, the system  630  of this embodiment may also comprise at least one driving circuit. Illustrative examples of the driving circuits include, but are not limited to, driving circuit(s) for the electronic paper panel  620  and the driving circuit(s) for the organic light-emitting diode  610 . 
     As discussed hereinabove, the organic light-emitting diode layer  610  is an active-matrix organic light-emitting diode layer. As is appreciated by those of ordinary skill in the art, it is possible to switch on/off the individual pixel of the active-matrix organic light-emitting diode layer  610  so that only a portion of the electronic paper panel  620  is illuminated while the other portion(s) may not be illuminated. 
     Is  FIG. 7  is a schematic diagram illustrating an electronic paper display  700  according to the seventh embodiment of the present invention. 
     Generally, electronic paper display  700  comprises an organic light-emitting diode layer  710 , an electronic paper panel  720 , a system  730 , and a touch panel  740 . The electronic paper display  700  and the electronic paper display  600  described hereinabove in connection with  FIG. 6  are substantially similar in structure, except that the electronic paper display  700  further comprises the touch panel  740 . Accordingly detailed descriptions regarding the arrangements and examples of the elements of electronic paper display  700  are omitted herein for the sake of brevity. 
     As shown in  FIG. 7 , the touch panel  740  is disposed on the upper surface of the organic light-emitting diode layer  710 . Illustrative examples of the touch panel  740  include, but are not limited to, resistive touch panels and capacitive touch panels. 
       FIG. 8  is a schematic diagram illustrating an electronic paper display  800  according to the eighth embodiment of the present invention. 
     Generally, electronic paper display  800  comprises an organic light-emitting diode layer  810 , an electronic paper panel  820 , a system  830 , and a touch panel  840 . The electronic paper display  800  and the electronic paper display  700  described hereinabove in connection with  FIG. 7  are substantially similar in structure, except that the touch panel  840  of the electronic paper display  800  is disposed between the electronic paper panel  820  and the organic light-emitting diode layer  810 . Accordingly detailed descriptions regarding the arrangements and examples of the elements of electronic paper display  800  are omitted herein for the sake of brevity. 
     In view of the foregoing detailed description, many advantages of the present invention are now apparent. Some of the advantages are discussed as follows, whereas other advantages of the present invention will be apparent to those of ordinary skill in the art in view of the specification, claims and drawings provided herein. 
     According to some embodiments of the present invention, electronic paper displays are provided with a light source and a light-guiding structure such that the light irradiated by the light source is reflected and scattered by the light-guiding structure and then illuminates the electronic paper panel. Alternatively, in some embodiments of the present invention, electronic paper displays are provided with an organic light-emitting diode layer serving as an active light source so as to illuminate the electronic paper panel. As such, users may view the contents of the e-readers by using the electronic paper display according to embodiments of the present invention, even under dim light or in the absence of environmental light. 
     As compared with conventional electronic paper displays that employ only a light source, the electronic paper displays according to some embodiments of the present invention provide better quality content by providing the electronic paper displays with a light source and a light-guiding structure such that the light can be evenly distributed across the electronic paper panel. Hence, the present electronic paper displays may provide users with a more satisfactory reading experience. 
     Similarly, the electronic paper displays according to some embodiments of the present invention are provided with an organic light-emitting diode layer as an active light source that may irradiate a more uniform light as compared with other light sources. As such, the present electronic paper displays provide better quality content which results in a more satisfactory reading experience. 
     Moreover, due to the more uniform distribution of light, it is possible to reduce the amount of the devices for irradiating light (such as light-emitting diodes). In addition, the pixels of the active-matrix organic light-emitting diode can be individually switched on or off so that only a portion of the active-matrix organic light-emitting diode layer irradiates light. In both instances, the power consumption of the electronic paper displays may be reduced. 
     Further, with respect to the electronic paper displays comprising a touch panel and a light-guiding structure, the light-guiding structure may optionally be formed on the upper substrate of the touch panel. As compared with providing an additional light-guiding element, integrating the light-guiding structure in the upper substrate of the touch panel may lower the manufacturing cost, reduce the overall thickness of the final product, and increase the light transmittance. In addition, the process for forming the light-guiding structure on the upper substrate is simple and compatible with existing manufacturing process. 
     It will be understood that the above description of embodiments is given by way of example only and that various modifications may be made by those with ordinary skill in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments of the invention. Although various embodiments of the invention have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those with ordinary skill in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention, and the scope thereof is determined by the claims that follow.