PATENT DOCUMENT

Publication Number: US-8749737-B2
Application Number: US-201113103726-A
Country: US
Kind Code: B2

Title: Display with color control

Abstract:
Techniques are provided for controlling the colors of reflected light out of a display surface in a display device, such that display discoloration (e.g., green tinting) may be reduced, particularly when the display is operating in bright ambient environments. In one embodiment, a display device may include a color filter black mask layer having an arrangement of red, green, and blue color filter areas, where the red and/or blue color filter areas are substantially greater than the green color filter area. In some embodiments, the display device may include red and blue color filter pigment resin areas which may be disposed over the reflective areas to increase the overall amount of red and blue light that will be generated by reflected light to result in a total light reflection that is substantially neutral in color.

Claims:
What is claimed is: 
     
       1. A display device comprising:
 a thin film transistor (TFT) layer comprising a plurality of reflective portions, a red pixel, a blue pixel, and a green pixel, wherein each reflective portion of the plurality of reflective portions comprises a data line, a gate line, or any combination thereof; and 
 a color filter and black mask layer disposed over the TFT layer, wherein the color filter and black mask layer comprises:
 a red color filter configured to be disposed over the red pixel of the display device; 
 a blue color filter configured to be disposed over the blue pixel of the display device; 
 a green color filter configured to be disposed over the green pixel of the display device, wherein an area of at least one of the red color filter and the blue color filter is greater than an area of the green color filter; and 
 a black mask configured to be disposed over a first reflective portion of the plurality of reflective portions, wherein the first reflective portion is coupled to the green pixel of the display device, and wherein a segment of a second reflective portion of the plurality of reflective portions coupled to either the red pixel or the blue pixel of the display device is not configured to be covered by the black mask. 
 
 
     
     
       2. The display device of  claim 1 , wherein each reflective portion of the plurality of reflective portions is coupled to one of the red pixel, the blue pixel, or the green pixel, wherein at least one of the red color filter and the blue color filter is disposed over the segment of the second reflective portion of the plurality of reflective portions. 
     
     
       3. The display device of  claim 2 , comprising one or more optical films disposed under the TFT layer, wherein the one or more optical films are configured to reflect impinging external light towards the color filter and black mask layer, wherein a total reflection out of the display surface is substantially neutral, wherein the total reflection out of the display surface comprises light reflected from the one or more optical films and light reflected from the segment of the second reflective portion of the plurality of reflective portions through at least one of the red color filter and the blue color filter. 
     
     
       4. The display device of  claim 1 , wherein the black mask is configured to separate the red, green, and blue color filters such that the area of the green color filter surrounded by the black mask is smaller than at least one of the area of the red color filter surrounded by the black mask and the area of the blue color filter surrounded by the black mask. 
     
     
       5. The display device of  claim 4 , wherein the color filter and black mask layer is configured such that the area of the green color filter surrounded by the black mask is approximately 1% to 40% smaller than at least one of the area of the red color filter surrounded by the black mask and the area of the blue color filter surrounded by the black mask. 
     
     
       6. The display device of  claim 1 , wherein the color filter and black mask layer is configured such that a total light reflection out of a display surface of the display device is substantially neutral, wherein the total light reflection comprises a red light reflecting out of the red color filter, a green light reflecting out of the green color filter, and a blue light reflecting out of the blue color filter. 
     
     
       7. The display device of  claim 1 , comprising a backlight assembly configured to illuminate light towards a display surface of the display device, wherein the TFT layer is disposed over the backlight assembly. 
     
     
       8. The display device of  claim 1 , wherein the area of at least one of the red color filter and the blue color filter is approximately 1% to 40% larger than the area of the green color filter. 
     
     
       9. A display device, comprising:
 a pixel matrix comprising a red pixel, a blue pixel, and a green pixel; 
 a red color filter disposed over the red pixel and first reflective portion coupled to the red pixel, wherein the first reflective portion comprises a first data line coupled to the red pixel, a first gate line coupled to the red pixel, or any combination thereof, the red color filter is configured to pass light having wavelengths in a visible red spectrum, and the first reflective portion is configured to reflect a portion of external light impinging the first reflective portion through the red color filter; 
 a blue color filter disposed over the blue pixel and a second reflective portion coupled to the blue pixel, wherein the second reflective portion comprises a second data line coupled to the blue pixel, a second gate line coupled to the blue pixel, or any combination thereof, the blue color filter is configured to pass light having wavelengths in a visible blue spectrum, and the second reflective portion is configured to reflect a portion of external light impinging the second reflective portion through the blue color filter; 
 a green color filter disposed over the green pixel, wherein the green color filter is configured to pass light having wavelengths in a visible green spectrum; and 
 a black mask configured to separate the red color filter, the green color filter, and the blue color filter from one another, wherein the black mask is disposed over a third reflective portion coupled to the green pixel, 
 wherein the third reflective portion comprises a third data line coupled to the green pixel, a third gate line coupled to the green pixel, or any combination thereof, and wherein the black mask does not cover either a first segment of the first reflective portion or a second segment of the second reflective portion. 
 
     
     
       10. The display device of  claim 9 , wherein an area of each of the red color filter and the blue color filter is greater than the area of the green color filter. 
     
     
       11. The display device of  claim 9 , wherein the black mask is configured to surround an area of the red color filter disposed over the first segment of the first reflective portion. 
     
     
       12. The display device of  claim 9 , wherein the black mask is configured to surround an area of the blue color filter disposed over the second segment of the second reflective portion. 
     
     
       13. The display device of  claim 9 , comprising one or more optical films configured to reflect external light impinging the display device, wherein the one or more optical films is configured to reflect portions of the external light through the red color filter, the green color filter, or the blue color filter. 
     
     
       14. The display device of  claim 13 , wherein a combination of light reflected by the one or more optical films and light reflected by the first and second reflective portions which propagate out of a display surface of the display device is substantially neutral in color. 
     
     
       15. The display device of  claim 9 , wherein an area of one or more of the red color filter and the blue color filter is approximately 1% to 40% larger than an area of the green color filter. 
     
     
       16. A method of controlling a color of total reflected light from a display device, the method comprising:
 reflecting light from an optical film in a backlight assembly of the display device; 
 color filtering the reflected light from the optical film using a plurality of color filters in a color filter and black mask layer, wherein the color filter and black mask layer comprises a black mask, a plurality of red color filters disposed over a plurality of red pixels, a plurality of green color filters disposed over a plurality of green pixels, and a plurality of blue color filters disposed over a plurality of blue pixels; 
 displaying the color filtered reflected light from the optical film on the display surface; 
 reflecting light from a plurality of reflective portions disposed on a thin film transistor (TFT) layer of the display device, wherein each reflective portion comprises a data line, a gate line, or any combination thereof, and each reflective portion of the plurality of reflective portions is coupled to a respective red pixel of the plurality of red pixels or a respective blue pixel of the plurality of blue pixels; 
 color filtering the reflected light from the plurality of reflective portions through one of the plurality of red color filters and the plurality of blue color filters in the color filter and black mask layer, wherein the black mask is disposed over each reflective portion coupled to a respective green pixel of the plurality of green pixels, the black mask does not cover first segments of each reflective portion coupled to a respective red pixel of the plurality of red pixels, and the black mask does not cover second segments of each reflective portion coupled to a respective blue pixel of the plurality of blue pixels; and 
 displaying the color filtered reflected light from the plurality of reflective portions on the display surface such that the total reflected light displayed on the display surface is substantially neutral in color, wherein the total reflected light displayed on the display surface comprises reflected light from the optical film, reflected light from the first segments of the reflective portions coupled to the plurality red pixels, and reflected light from the second segments of the reflective portions coupled to the plurality of blue pixels. 
 
     
     
       17. The method of  claim 16 , wherein the reflected light from the optical film is displayed on the display surface substantially concurrently with the reflected light from the plurality of reflective portions. 
     
     
       18. The method of  claim 16 , comprising transmitting internal light from a backlight assembly through the plurality of color filters in the color filter and black mask layer, wherein the total reflected light comprises the internal light transmitted through the plurality of color filters. 
     
     
       19. A method of manufacturing a display device having reduced discoloration, the method comprising:
 providing a display panel configured to emit modulated light to be displayed through the display device, wherein the display panel comprises first reflective portions and second reflective portions, and each first reflective portion comprises a data line, a gate line, or any combination thereof; 
 configuring a color filter and black mask layer to comprise an arrangement of red color filters, green color filters, and blue color filters each surrounded by black mask material, such that the red color filters are each larger than each of the green color filters; and 
 disposing the color filter and black mask layer over the display panel, wherein the black mask material surrounding the red color filters and the blue color filters does not cover segments of the first reflective portions disposed under the red color filters and the blue color filters, and the black mask material surrounding the green color filters is configured to cover the second reflective portions disposed under the green color filters. 
 
     
     
       20. The method of  claim 19 , wherein the red color filters are each configured to be approximately 1% to 40% larger in area than each of the green color filters. 
     
     
       21. The method of  claim 19 , wherein configuring the color filter and black mask layer comprises configuring each of the blue color filters to be larger in area than each of the green color filters. 
     
     
       22. The method of  claim 19 , wherein the blue color filters are each configured to be approximately 1% to 40% larger in area than each of the green color filters.

Description:
BACKGROUND 
     The present disclosure relates generally to display devices, and more particularly, to techniques for controlling colors displayed by display devices. 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     Liquid crystal displays (LCDs) are commonly used as screens or displays for a wide variety of electronic devices, including such consumer electronics as televisions, computers, and handheld devices (e.g., cellular telephones, audio and video players, gaming systems, and so forth). Such LCD devices typically provide a flat display in a relatively thin package that is suitable for use in a variety of electronic goods. 
     LCD devices typically include multiple layers, including a backlight, an LCD panel having a pixel matrix configured to selectively modulate the amount and color of light transmitted from the backlight, and a color filter layer which enables specific colors of light to be emitted (e.g., red, green, and blue). LCD devices also typically include one or more optical layers from which external light (i.e., ambient light, such as from sunlight, lamplight, etc.) may be reflected. Due to the reflection of external light, LCD devices may be readable under direct sunlight, even if the backlight is not actively transmitting light through the LCD device. More specifically, external light may propagate through the layers of the LCD devices to be reflected by one or more optical layers out of the LCD device. The reflected external light may form images on the display surface as it passes through the liquid crystal panel and color filter layer. However, the reflection of external light may sometimes contribute to undesirable display effects. For instance, reflected external light may contribute to a green tint on a display surface, particularly in brightly lit environments. 
     SUMMARY 
     A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below. 
     The present disclosure generally relates to techniques for controlling the reflection of colors out of a display. In particular, display discoloration, such as green tinting, may be reduced, particularly when the display is operating in bright ambient environments. In one embodiment, a color filter and black mask layer may be configured to have red and/or blue color filters which each cover a larger area through which reflected light is color-filtered, compared to green color filters. For example, red and/or blue color filters may be extended over reflective areas of corresponding red and/or blue pixels, such as the data lines, gate lines, thin film transistors (TFTs), and storage capacitors in each respective pixel. In some embodiments, the black mask regions of each pixel may be altered to increase the amount of red and blue light that is reflected out from the display. Therefore, in some embodiments, the amount of external light which reflects through red and/or blue color filters may be controlled (e.g., increased) to result in displayed images having a substantially neutral color. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which: 
         FIG. 1  is a block diagram of an electronic device, in accordance with aspects of the present disclosure; 
         FIG. 2  is a perspective view of a computer in accordance with aspects of the present disclosure; 
         FIG. 3  is a perspective view of a handheld electronic device in accordance with aspects of the present disclosure; 
         FIG. 4  is a cross-sectional side view of the display in the display device illustrated in  FIG. 1 , in accordance with aspects of the present disclosure; 
         FIG. 5  is a diagram representing light transmission and reflection in the display of  FIG. 4  in accordance with aspects of the present disclosure; 
         FIG. 6  is a diagram representing light reflection through a color filter and black mask layer of the display of  FIG. 4  in accordance with aspects of the present disclosure; 
         FIG. 7  is a diagram representing increased light reflection through red and blue color filters in the display of  FIG. 4  in accordance with aspects of the present disclosure; 
         FIG. 8  is a top view of a color filter and black mask layer of red, green, and blue pixels; 
         FIG. 9  is a top view of red, green, and blue color filter pigment resin areas in a first embodiment in accordance with aspects of the present disclosure; 
         FIG. 10  is a top view of a color filter and black mask layer having controlled black mask areas over the red and blue pixels in a second embodiment in accordance with aspects of the present disclosure; and 
         FIG. 11  is a top view of a color filter and black mask layer having exposed color filter regions over reflective areas in the red and blue pixels in a third embodiment, in accordance with aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     One or more embodiments are directed towards controlling the light reflected from a display device. Display devices typically include multiple layers, including a backlight, an pixel matrix layer configured to selectively modulate the amount and color of light transmitted from the backlight, and a color filter layer which color filters light such that specific wavelengths of light are emitted (e.g., visible light having red, green, and blue wavelengths). Display devices also typically include one or more optical layers from which external light (i.e., ambient light, such as from sunlight, lamplight, etc.) may be reflected. In some embodiments, the reflected external light may propagate to the display surface to contribute to the illumination of the display, thereby conserving power consumption while increasing pixel illumination. Moreover, in some embodiments, due to the reflectivity of such optical layers, display devices may be readable in bright ambient conditions (e.g., under direct sunlight or under lamplight), even if the backlight is not actively transmitting light through the display. More specifically, external light may impinge a top surface of the display device and propagate through the display layers (e.g., the pixel matrix layer, the color filter layer, etc.) to be reflected out of the display by one or more optical layers. The reflected external light may form colored images on the display surface as it passes through the light modulating pixel matrix layer and the color filter layer. 
     While the reflection of external light may be desirable for certain purposes (e.g., increasing illumination without expending extra power, displaying colored images without transmitting backlight, etc), such reflections may also contribute to undesirable display effects. For instance, due to the configuration of typical display devices and certain properties of visible light, more light having green wavelengths may be reflected out of the display, in comparison to light having red or blue wavelengths. Increased reflections of light having green wavelengths may be perceived by a user of the display device as a green tint throughout the display surface, particularly in brightly lit environments. Such a green tint may decrease the quality of the displayed images. 
     In one or more embodiments, a display device includes a color filter and/or black mask layer configured to result in a substantially neutral color of light propagating out of a display screen of the display device. Propagating light may include any light which propagates into or out of layers in a display device, including transmitted internal light (e.g., backlight, OLEDs, or other light source within the display device) and reflected external light (e.g., sunlight, lamplight, or other ambient light from a source external to the display device). Moreover, reflected external light may include portions of external light which reflect from any reflective surface within the display device, including, for example, optical layers, reflective layers, transmissive layers, and/or other reflective components of the display. Light which propagates out of the display screen may be viewed by a user of the display device and may include a combination of transmitted internal light and reflected external light, depending on the operation of the display device and/or the ambient light conditions in which the display device is operating. Furthermore, light propagating out of the display device may be referred as substantially balanced when the display device can generate a neutral color to be viewed by a user, even when the display device is operating in bright ambient conditions. For instance, in display devices having red, green, and blue colored pixels, the color filter and/or black mask layer may be configured such that the red, green, and blue wavelengths of light propagating out of the display screen are substantially balanced to generate a neutral color. 
     In one embodiment, display discoloration (i.e., when the light propagating out of the display screen is not substantially balanced) can be reduced by controlling size of certain color filters (e.g., red, green, and/or blue) through which reflected light can be transmitted and color filtered. For example, display discoloration such as green tinting may be reduced by configuring the color filter and black mask layer such that red pixels and/or blue pixels have a larger area for color filtering red and/or blue reflected light, as compared to green pixels. 
     In one embodiment, red and blue pixels may each have a corresponding red or blue color filter pigment resin area that is disposed not only over the transmissive areas of the respective red of blue pixel, but also over the reflective areas of the respective pixel. For example, the red or blue color filter areas may be disposed over reflective areas such as data lines, gate lines, thin film transistors (TFTs), and storage capacitors in each respective red pixel or blue pixel. In some embodiments, the black mask regions of each red pixel or blue pixel may be altered to control the amount of red and blue light is reflected out from the display, such that the total red, blue and green light propagating out of the display screen is substantially balanced. Therefore, in some embodiments, the color filter and black mask layer may be configured to increase the areas through which external light may be reflected through red and/or blue color filter pigment resin areas such that the total red, blue, and green light propagating out of the display screen is substantially balanced. By increasing the areas through which red and/or blue light is reflected, the color of displayed images may be neutralized, and discoloration such as green tinting may be reduced. 
     Prior to discussing the above summarized techniques in detail, it is useful to understand certain examples of devices in which such techniques may be used. As may be appreciated, electronic devices may include various internal and/or external components which contribute to the function of the device. For instance,  FIG. 1  is a block diagram illustrating components that may be present in one such electronic device  10 . Those of ordinary skill in the art will appreciate that the various functional blocks shown in  FIG. 1  may include hardware elements (including circuitry), software elements (including computer code stored on a computer-readable medium, such as a hard drive or system memory), or a combination of both hardware and software elements.  FIG. 1  is only one example of a particular implementation and is merely intended to illustrate the types of components that may be present in the electronic device  10 . For example, in the presently illustrated embodiment, these components may include a display  12 , input/output (I/O) ports  14 , input structures  16 , one or more processors  18 , one or more memory devices  20 , non-volatile storage  22 , expansion card(s)  24 , networking device  26 , and power source  28 . 
     The display  12  may be used to display various images generated by the electronic device  10 . The display  12  may be any suitable display, such as a liquid crystal display (LCD) or an organic light-emitting diode (OLED) display. Additionally, in certain embodiments of the electronic device  10 , the display  12  may be provided in conjunction with a touch-sensitive element, such as a touch-screen, that may be used as part of the control interface for the device  10 . The display  12  may also include a light source (e.g., backlight, OLED panel, etc.), various optical layers, and a matrix of pixels and circuitry for modulating the transmittance of light through each pixel to display an image, as will be discussed. 
     The electronic device  10  may take the form of a computer system or some other type of electronic device. Such computers may include computers that are generally portable (such as laptop, notebook, tablet, and handheld computers), as well as computers that are generally used in one place (such as conventional desktop computers, workstations and/or servers). In certain embodiments, electronic device  10  in the form of a computer may include a model of a MacBook®, MacBook® Pro, MacBook Air®, IMac®, Mac® mini, or Mac Pro® available from Apple Inc. of Cupertino, Calif. By way of example, an electronic device  10  in the form of a laptop computer  30  is illustrated in  FIG. 2  in accordance with one embodiment. The depicted computer  30  includes a housing  32 , a display  12  (e.g., in the form of an LCD  34  or some other suitable display), I/O ports  14 , and input structures  16 . 
     The display  12  may be integrated with the computer  30  (e.g., such as the display of the depicted laptop computer) or may be a standalone display that interfaces with the computer  30  using one of the I/O ports  14 , such as via a DisplayPort, Digital Visual Interface (DVI), High-Definition Multimedia Interface (HDMI), or analog (D-sub) interface. For instance, in certain embodiments, such a standalone display  12  may be a model of an Apple Cinema Display®, available from Apple Inc. 
     Although an electronic device  10  is generally depicted in the context of a computer in  FIG. 2 , an electronic device  10  may also take the form of other types of electronic devices. In some embodiments, various electronic devices  10  may include mobile telephones, media players, personal data organizers, handheld game platforms, cameras, and combinations of such devices. For instance, as generally depicted in  FIG. 3 , the device  10  may be provided in the form of handheld electronic device  36  that includes various functionalities (such as the ability to take pictures, make telephone calls, access the Internet, communicate via email, record audio and video, listen to music, play games, and connect to wireless networks). By way of further example, handheld device  36  may be a model of an IPod®, IPod® Touch, or IPhone® available from Apple Inc. In the depicted embodiment, the handheld device  32  includes the display  12 , which may be in the form of an LCD  34 . The LCD  34  may display various images generated by the handheld device  32 , such as a graphical user interface (GUI)  38  having one or more icons  40 . 
     In another embodiment, the electronic device  10  may also be provided in the form of a portable multi-function tablet computing device (not illustrated). In certain embodiments, the tablet computing device may provide the functionality of two or more of a media player, a web browser, a cellular phone, a gaming platform, a personal data organizer, and so forth. By way of example only, the tablet computing device may be a model of an IPad® tablet computer, available from Apple Inc. 
     With the foregoing discussion in mind, it may be appreciated that an electronic device  10  in either the form of a computer  30  ( FIG. 2 ) or a handheld device  36  ( FIG. 3 ) may be provided with a display device  10  in the form of an LCD  34 . As discussed above, an LCD  34  may be utilized for displaying respective operating system and/or application graphical user interfaces running on the electronic device  10  and/or for displaying various data files, including textual, image, video data, or any other type of visual output data that may be associated with the operation of the electronic device  10 . 
     With the foregoing in mind, and referring once again to the figures,  FIG. 4  depicts a cross-sectional side view of an example of a display, such as the display  12  illustrated in  FIG. 1 . The display  12  includes a top polarizing layer  42  and a bottom polarizing layer  58  each configured to polarize light from a backlight assembly  78 . Between the top and bottom polarizing layers  42  and  58 , the display  12  may include a thin film transistor (TFT) layer  50 , liquid crystal layer  48 , and color filter and black mask layer  46  which together selectively modulate and color filter the light emitted through the backlight assembly  78 . One or more layers of the display  12  may be encapsulated and/or surrounded by a display frame  68 . 
     The backlight assembly  78  may include a light source  62 , which may include, for example, a light emitting diode (LED), cold cathode fluorescent lamps (CCFLs), and/or hot cathode fluorescent lamps (HCFLs), or other suitable lighting device. In one embodiment, the backlight assembly  78  includes a light guide  64  configured to guide the light from the internal light source  62  throughout the display area of the display  12 . The backlight assembly  78  may also include a reflector  66  disposed beneath the light guide  64  and may be configured to reflect and/or direct the light emitted by the light source  62  such that the emitted light is transmitted towards the upper layers (e.g., towards the top polarizer  42  and out of the display surface) of the display  12 . In some embodiments, the backlight assembly  78  may also include one or more optical films  60  disposed over the light guide  64  through which light from the light guide  64  is transmitted towards the upper layers of the display  12 . In some embodiments, the one or more optical films  60  may include reflective properties, and may reflect portions of external light which impinge the display surface and propagate through the layers of the display  12 . 
     In some embodiments, the thin film transistor (TFT) layer  50  is disposed above the bottom polarizer  58  which is disposed over the backlight assembly  78 . For simplicity of illustration, the TFT layer  50  is depicted as a generalized structure in  FIG. 4 . In practice, the TFT layer  50  may itself include various conductive, non-conductive, and semiconductive layers and structures which generally form the electrical devices and pathways which drive operation of the each pixel of the display  12 . In some embodiments, each pixel in the display  12  may be controlled by the display driver  54  which may be coupled to display driving circuitry  56 . For example, in an embodiment in which the display  12  is an FFS LCD display, the display driving circuitry  56  may control the display driver  54  to drive the TFT layer  50  through data lines (also referred to as “source lines”) and scanning lines (also referred to as “gate lines”) to activate pixel electrodes, and common electrodes (as well as other conductive traces and structures). Such conductive structures may be formed using transparent conductive materials, such as indium tin oxide (ITO) or indium zinc oxide (IZO), for example. In some embodiments, such conductive structures may have reflective properties which may be suitable for reflecting portions of external light which impinge the surface of the display  12 , as will be further discussed. 
     The TFT layer  50  may further include insulating layers (such as a gate insulating film) formed from suitable transparent materials (such as silicon oxide) and semiconductive layers formed from suitable semiconductor materials (such as amorphous silicon). In general, the respective conductive structures and traces, insulating structures, and semiconductor structures may be suitably disposed to form the respective pixel electrodes and common electrodes, a TFT, and the respective data and scanning lines used to operate (e.g., activate or deactivate) each pixel in the display  12 . 
     The liquid crystal layer  48  may be disposed over the TFT layer  50  and may include liquid crystal molecules suspended in a fluid or embedded in polymer networks. The liquid crystal molecules may be oriented or aligned with respect to an electrical field generated by the TFT layer  50 . In practice, the orientation of the liquid crystal molecules in the liquid crystal layer  48  determines the amount of light (e.g., provided by the light source  64 ) that is transmitted through each pixel of the display  12 . For example, applying a voltage to the TFT layer  50  of the pixel may generate an electric field in the liquid crystal layer  48 , such that the liquid crystal molecules in the liquid crystal layer  50  may be aligned to affect the polarization of light propagating through the liquid crystal layer  48 . Based on the polarization of the light passing out from the liquid crystal layer  48 , the light may be absorbed by the top polarizer  42  or transmitted through the top polarizer  42 . 
     Disposed over the liquid crystal layer  48  opposite from the TFT layer  50  may be one or more alignment and/or overcoating layers interfacing between the liquid crystal layer  48  and an overlying color filter and black mask layer  46 . In some embodiments, the color filter and black mask layer  46  may be sealed with the liquid crystal layer  48  and the TFT layer  50  by a suitable sealant  52 . While the color filter and black mask layer  46  in  FIG. 4  is illustrated as a generalized structure, the color filter and black mask layer  46  may actually include an arrangement of red, green, and blue pigment resin areas, each surrounded by a black mask and disposed over a pixel, as will be discussed in further detail. The red, green, and blue pigment resin areas may be configured such that light passing through each color filter pigment resin area may have substantially red, green, or blue wavelengths, respectively. The black mask may be a light-opaque mask or matrix which defines a red, green, or blue pixel area and prevents light transmitted through the aperture and color filter pigment resin areas from diffusing or “bleeding” into adjacent pixels. In some embodiments, each pixel of the display  12  may correspond to a primary color (e.g., red, green, or blue) when light is transmitted from the backlight assembly  78  through the liquid crystal layer  48  and the color filter and black mask layer  46 . 
     As previously discussed, light which propagates within the display  12  may include internal light (e.g., light emitted from a backlight assembly  78  or any other suitable internal light source) and external light (e.g., light external to the display  12  that impinges a top surface of the display  12 ). Light which propagates out of the display surface (i.e., out of the top polarizer  42 ) may include transmissions of internal light or reflections of external light. 
     For example,  FIG. 5  illustrates light transmission and reflection in the display  12  of  FIG. 4 . As illustrated in  FIG. 5 , internal light  70  may be emitted out from the light guide and through the optical films of the backlight assembly  78 . The internal light  70  may be polarized by the bottom polarizer  58  and selectively modulated (e.g., by intensity and in color) by the TFT layer  50 , the liquid crystal layer  48 , and the color filter and black mask layer  46 . The internal light  70  may be polarized by the top polarizer  42  and transmitted out of the display surface to be viewed by a user of the display  12 . 
     External light  72  from any light source external to the display  12  may impinge the top surface of the display  12  and may propagate through layers of the display  12 . Once external light  72  impinges the display surface to propagate within the layers of the display  12 , the light, referred to as impinging light  74 , may be modified in polarization, direction, and/or wavelength, etc. The impinging light  74  may be reflected by one or more optical films  60  in the display  12 , resulting in reflected light  76 . The reflected light  76  may also be modified in polarization, direction, and/or wavelength, etc. before it is transmitted out of the surface of the display  12  to be viewed by a user. 
     As reflected light  76  which is viewed by a user passes through the color filter and black mask layer  46 , the reflected light  76  may be different in wavelength (i.e., different in color) depending on the color of color filter pigment resin area the reflected light  76  passes through before it propagates out of the surface of the display  12 . For example, as illustrated in  FIG. 6 , impinging light  74  may pass through the color filter and black mask layer  46 , which includes an arrangement of red color filter pigment resin areas  84 , green color filter pigment resin areas  86 , and blue color filter pigment resin areas  88 , referred to generally as a red filter  84 , green filter  86 , and blue filter  88 , respectively. Each of the red, green, and blue filters  84 ,  86 , and  88  may be surrounded by a black mask  82 , such that the black mask and filter  84 ,  86 , or  88  define the area and color of a red pixel  96 , a green pixel  98 , or a blue pixel  100  in the display  12 . 
     Light transmitted from the backlight assembly  78  is modulated by the TFT layer  50  (which includes reflective areas  80  such as TFTs, pixel electrodes, gate lines, etc.) and liquid crystal layer  48  ( FIGS. 4 and 5 ) and transmitted through a red filter  84 , green filter  86 , or blue filter  88 . Similarly, when external light impinges the display surface and impinges the layers of the display  12 , the impinging light  74  may propagate through the red filter  84 , green filter  86 , or blue filter  88 , reflected by the backlight assembly  78  and be transmitted through the red filter  84 , green filter  86 , or blue filter  88  again to be viewed as a user as either red light  90 , green light  92 , or blue light  94 . 
     Therefore, external light propagates through the layers of a display  12  twice before the reflections of external light are viewed by a viewer. However, due to certain properties of visible light, and due to the configuration of typical displays, certain wavelengths of light may be attenuated before the reflected light is transmitted out of a display to be viewed by a user, such that less light having certain wavelengths is visually perceived by the user. For example, in some displays, less red light  90  or blue light  94  may be reflected out of a typical display than green light  92 , possibly resulting in undesirable display characteristics, such as green tinting. 
     In some embodiments, the color filter and black mask layer  46  may be configured such that a total light propagating out of the display  12  may be substantially neutral in color. As illustrated in  FIG. 7 , the color filter and black mask layer  46  may include red filters  84  and blue filters  88  each having larger areas than the area of green filters  86 . In some embodiments, the red filter  84  and blue filter  88  may also be disposed over a reflective portion  80  of the TFT layer  50  for each corresponding pixel  96 ,  98 , or  100 . For example, the red filter  84  may be extended over the reflective portion  80  of a red pixel  96 . In addition to the red light  90  reflecting from the backlight assembly  78  and through the red filter  84 , red light  90   a  may also reflect from the reflective portion  80  and through the red filter  84 . The green filter  86  may be significantly smaller in area (e.g., approximately 1% to 40% smaller in area) in comparison to the red filter  84 , such that green light  86  is reflected from the backlight assembly  78 , but not significantly from a reflective portion  80  corresponding to the green pixel  98 . The blue filter  88  may be disposed over a reflective portion  80  corresponding to the blue pixel  100 . For example, as illustrated in  FIG. 7 , the blue filter  88  may be disposed over a reflective portion  80  coupled to the blue pixel  100 , such that blue light  94   a  is reflected from the reflective portion  80  through the blue filter  88 , in addition to the blue light  94  reflected by the backlight assembly  78 . 
     Moreover, in some embodiments, the reflective portions  80  may include reflective pixel elements and/or reflective materials disposed beneath certain filters in the color filter and black mask layer  46 . As discussed, the reflective portions  80  may include TFTs, pixel electrodes, gate lines, etc. Additionally, the reflective portions  80  may also include reflective materials (e.g., aluminum) which are disposed beneath the red filter  84  and/or the blue filter  88 , such that red light  90   a  and blue light  94   a  may be displayed on a display surface in addition to the red light  90 , green light  92 , and blue light  94  which is reflected from the backlight assembly  78  to be transmitted through the filters  84 ,  86 , and  88 . 
     A top view of a typical color filter and black mask layer (for which the cross-sectional side view is illustrated in  FIG. 6 ) is provided in  FIG. 8 , where each of the red filter  84 , green filter  86 , and blue filter  88  has approximately the same area which is defined by the surrounding black mask  82 . The black mask  82  may also be disposed over reflective portions  80  of each pixel. 
       FIG. 9  illustrates a top view of one embodiment including a red color filter  84 , a green color filter  86 , and a blue color filter  88 . The top view of the color filters  84 ,  86 , and  88  may illustrate the color filter portion of the embodiment illustrated in the cross-sectional side view of  FIG. 7 . Though not necessarily drawn to scale,  FIG. 9  represents that each of the red color filter  84  and the blue color filter  88  are larger in area than the green color filter  86 . Furthermore, in some embodiments, the red and blue color filters  84  are also disposed over the corresponding reflective portions  80  of red and blue pixels. 
     In some embodiments, as illustrated in the color filter and black mask layer  46   a  of  FIG. 10 , the black mask  82  may be shaped such that red and blue pixels have a larger area of a red filter  84  and blue filter  88  compared to an area of green filter  86 . For example, in some embodiments, the areas of the each of the red filter  84  and blue filter  88  may be approximately 1% to 40% larger in area than the area of the green filter  86 . The red and blue filters  88  may be areas of pigment resin rather than areas of black mask material. Impinging light  74  ( FIGS. 6 and 7 ) which reflects from reflective optical layers of the backlight assembly  78  or from a reflective portion  80  of a red pixel  96  or a blue pixel  100  may pass through the red filter  84  or blue filter  88  to be viewed as red light  90  or blue light  94 . 
       FIG. 11  illustrates yet another embodiment of a color filter and black mask layer  46   b  configured to increase the areas through which light can be reflected as red light  90  and blue light  94 . The red filter  84  and the blue filter  88  may each be disposed over respective reflective portions  80 , such that impinging light  74  may be reflected off the reflective portions  80  and transmitted through the red filter  84  or blue filter  88  to be viewed as red light  90  or blue light  94 . The black mask  82  may surround the red and blue filters  84  and  88  without covering the reflective portions  80  of the red and blue pixels  96  and  100 . In some embodiments, the green filter  86  may also be extended over a portion of a respective reflective portion  80 . For example, such techniques may increase the total reflection the display  12 , thereby increasing illumination from the display  12  in brightly lit environments. 
     In accordance with the present techniques, even if green light  92  tends to attenuate less than red light  90  or blue light  94 , the larger areas of the red filter  84  and/or blue filter  88  may compensate for such properties of light, such that the total red light  90  (and  90   a ), green light  92 , and blue light  94  (and  94   a ) may be substantially neutral in color. 
     The present techniques may include any combination of the embodiments described above, as well as various other configurations of red filters  84 , green filters  86 , blue filters  88 , and black mask  84 . In some embodiments, the red filter  84 , green filter  86 , and blue filter  88  may all have different sizes of exposed areas in the black mask  84 . For example, in some embodiments, only one of the red filter  84 , green filter  86 , or blue filter  88  may be disposed over a larger area than the other filters. Depending on the configuration of the display  12 , the pigment resin filters in the color filter and black mask layer  46  may be configured such that the light propagating out of the display surface may be substantially neutral in color, even in brightly lit environments. Embodiments may include any combination of configuring the areas through which light can be reflected as red light  90 , green light  92 , or blue light  94 , such that the light propagating from the display surface may be substantially neutral. 
     The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure.

Metadata:
Filing Date: 20110509
Publication Date: 20140610
Grant Date: 20140610
Priority Date: 20110509
Inventors: CHEN CHENG
ZHONG JOHN Z.
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F2201/52", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B5/223", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F2201/52", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133512", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B5/201", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B5/223", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133514", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B5/201", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133514", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K50/865", "inventive": false, "first": false, "tree": "[]"}, {"code": "H10K59/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/38", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/133512", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K59/8792", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 47141743