KR20110043729A - Transflective display with white tuning - Google Patents

Abstract

In one embodiment, the multi-mode liquid crystal display comprises pixels, each pixel comprising sub-pixels, each sub pixel comprising a first polarization layer; A second polarization layer; A first substrate layer and an oppositely directed second substrate layer, wherein the first and second substrate layers are interposed between the first polarization layer and the second substrate layer; A liquid crystal material between the first substrate layer and the second substrate layer; A first reflective layer adjacent to the first substrate layer and including at least one opening forming part of a transmisive part of the sub-pixel, wherein the remaining portion of the first reflective layer is the sub-pixel Forming a part of the reflecting portion of-; A first filter of a first color facing the transmitter and covering the transmitter, the first filter having an area wider than that of the transmitter; And a second filter of a second color facing the reflector and partially covering the reflector, wherein the second color is different from the first color.

Description

Reflective display with white tuning {TRANSFLECTIVE DISPLAY WITH WHITE TUNING}

The present disclosure relates generally to displays. More specifically, the disclosure relates to a multi-mode liquid crystal display (LCD).

The ways described in this section are ways that can be pursued, but not necessarily ways previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the ways described in this section are merely recognized as prior art by the content contained in this section.

Monochromatic liquid crystal displays (LCDs), such as those used for gasoline pump display clocks, are typically optimized for the intermediate spectrum of the visible light spectrum. Compared to green, which is located in the middle of the spectrum, red and blue light are not transmitted well. Therefore, monochrome LCDs may look greenish even when displaying black-and-white or grayscale images. Monochromatic LCDs are also inadequate for display color images or video.

Color LCDs can be used to display black-and-white or gray scale images. Each pixel of the color LCDs includes three or more color sub-pixels that can be used to simulate different shades of gray. However, when used as monochrome displays, the resoulation of color LCDs is typically limited by an area of pixels three times larger or coarse than the area of each sub-pixel. Color artifacts can remain visible at a spot, which causes viewers to see a pale tint of red or blue around the edges that are assumed to be black or gray scale characteristics.

Since the light passing through the color filters of the color sub-pixels is attenuated, color LCDs may use backlights in addition to or in place of ambient light. As a result, the power consumption of color LCDs is high to obtain acceptable resolution, even when used as a monochrome display.

LCDs are typically refreshed at 30. 60. or 120 frames per second. At these frame rates, LCDs consume much more power at lower rates. For example, at 60 frames per second, the LCD may consume twice as much power as at 30 frames per second.

1. General Overview

In an embodiment, the multi-mode LCD described later provides better resolution and readability compared to existing LCDs. In an embodiment, the power usage / consumption required by the LCD is reduced. In an embodiment, a solar readable display is provided in an LCD. In an embodiment, an indoor light readable display is provided in an LCD.

In some embodiments, the multi-mode LCD may comprise a plurality of pixels substantially along the surface of the plane, each pixel comprising sub-pixels. The sub-pixel in the plurality of sub-pixels includes a first polarization layer having a first polarization axis and a second polarization layer having a second polarization axis. The sub-pixel also includes a first substrate layer and a second substrate layer opposite to the first substrate layer. The sub-pixel includes a first reflective layer adjacent to the first substrate layer. The first substrate layer may be made of a roughened metal and includes at least one opening that partially forms the transmissvie part of the sub-pixel. The remainder of the first reflective layer covered by the metal in the sub-pixel forms part of the reflective part of the sub-pixel. In some embodiments, the first color filter of the first color faces the transmitter and covers the transmitter and has a larger area than the area of the transmitter, while the second color filter of the second color has the reflection Opposite the part and partially covering the reflecting part. The second color is different from the first color.

The multi-mode LCD has the first reflective layer on one side of the first electrode layer, while the second reflective layer is on the opposite side of the first electrode layer. This second reflective layer may be made of metal and includes at least one opening that is part of the transfer portion of the sub-pixel.

In an embodiment, the multi-mode LCD includes a light source for illuminating the multi-mode display. In an embodiment, the spectrum of color is generated from the light from the light source (or backlight) using a diffraction or micro light source film.

In an embodiment, color filters (e.g., the first color filter of the first color) may be transferred to the transmitter of the pixel, and other color filters (e.g., the second color filter of the second color). ) With respect to the region of the reflecting portion of the pixel allows for solid white-point shifting and strong readability in ambient light. In an embodiment, the black matrix mask typically used for color filters is removed. Additionally, an embodiment provides horizontally oriented sub-pixels to improve the resolution of the LCD in the color transfer mode. Additionally, an embodiment provides vertically oriented sub-pixels to enhance the resolution of the LCD in the color transfer mode. Moreover, the embodiment reduces the required frame rate of the LCD when used in the hybrid field sequential scheme, thereby providing the light between the two colors while the third color (typically green) is always on. Makes it possible to switch. In an embodiment, colors are generated from the backlight by eliminating the need for the color filters. In an embodiment, color filters are used only for the green color pixels, by eliminating the need to use additional masks to make the color filter arrangement.

In an embodiment, the cross-sectional area of the reflecting portion of the sub-pixel may exceed half of the total cross-sectional area of the total sub-pixel. For example, the reflector may account for 70% to 100% of the plurality of pixels. In an embodiment, in the multi-mode LCD, 1% to 50% of the reflectors in the sub-pixel are covered with one or more color filters.

In an embodiment said transmitting part occupies an interior part of the cross section of said sub-pixel. In an embodiment, said first filter and said second filters of said other colors are new monochrome colorless for said sub-pixel from a previously tinged white point. ) Can be configured to shift to a white spot. In an embodiment, the transmission unit occupies 0% to 30% of the plurality of pixels. In an embodiment, said one or more color-filters are different colors. In an embodiment, said one or more color-filters have the same thickness.

In an embodiment, the multi-mode crystal display further comprises one or more colorless spacers disposed above the reflecting portion. In an embodiment, the one or more colorless spacers have the same thickness In an embodiment, the one or more colorless spacers have different thicknesses.

In an embodiment, said multi-mode liquid crystal display further comprises a driving circuit for providing pixel values to a plurality of switching elements, said plurality of switching elements determining light to transmit through said transmission. In an embodiment, the drive circuit further comprises a transistor-transistor-logic (TTL) interface. In an embodiment, the multi-mode liquid crystal display further comprises a timing control circuit for refreshing the pixel values of the multi-mode liquid crystal display.

In an embodiment, the multi-mode liquid crystal display as described herein forms part of a computer, including but not limited to laptop computer, notebook computer, ebook reader, cell phone, and netbook computer.

Various embodiments relate to liquid crystal displays (LCDs) that can operate in multi-mode, monochrome reflection mode, and color transmission mode. The various modifications related to the above-described preferred embodiments and the generic principles and the features described herein will be very clear to those skilled in the art. Therefore, the disclosure is not intended to be limited to the embodiments shown above, but is to be accorded the widest scope consistent with the principles and features described herein.

Various embodiments of the invention will be described hereinafter with reference to the accompanying drawings, which are provided for illustrative purposes but not for limiting the invention, wherein similar designations denote similar elements.
1 is a cross-sectional view of a sub-pixel of an LCD.
2 shows the placement of three pixels (nine sub-pixels) of the LCD.
3 shows the operation of the LCD in the monochrome reflective mode.
4 illustrates the operation of the LCD in color transfer mode by using a partial color filter scheme.
5 illustrates the operation of the LCD in color transfer mode by using a hybrid field sequential scheme.
6 shows an example of configuration in a multi-mode LCD operating at low field rate without flicker.

 2. Structural Summary

1 is a cross-sectional view of a sub-pixel 100 of an LCD. The sub-pixel 100 includes a liquid crystal material 104, a sub-pixel electrode (or first electrode layer) 106 including switching elements, a common electrode (or a second electrode layer) 108, an electrode 106. The first reflective layer 160 on one side of the second reflective layer 150 on the other side of the electrode 106, the transmitter 112, the first and second substrate layers 114, spacers ( 118a, 118b, first polarization layer 120, and second polarization layer 122.

In one embodiment, the first and second reflective layers 160 and 150 have an opening on top of the transmitter 112. The surface of the first reflective layer 160 forms a part of the reflector 110. The surface of the second reflective layer 150 may be used to reflect light incident from the left side of the surface. In one embodiment, the light source 102 or ambient light 124 illuminates the sub-pixel 100. Examples of light source 102 include, but are not limited to, light emitting diode backlights (LEDs), cold-cathode fluorescent backlights (CCFLs), and the like. The ambient light 124 may be sunlight or an external light source. In an embodiment, optically active material, liquid crystal material 104 rotates the polarization axis of the light from light source 102 or ambient light 124. The liquid crystal 104 may be twisted nematic (TN), electrically controlled birefringence (ECB), or the like. In one embodiment, the rotation of the polarization orientation of the light is determined by the potential difference applied between the sub-pixel electrode 106 and the common electrode 108. In one embodiment, sub-pixel electrode 106 and common electrode 108 may be constructed by iridium tin oxide (ITO). Moreover, each sub-pixel is provided to the sub-pixel electrode 106, while the common electrode 108 is common to all sub-pixels and the pixels are present in the LCD.

In one embodiment, reflector 110 is electrically conductive and reflects ambient light 124 to illuminate sub-pixel 100. The first reflective layer 160 is made of metal and electrically connected to the sub-pixel electrode 106 to provide a potential difference between the reflector 110 and the common electrode 108. The transmitter 112 transmits light from the light source 102 to illuminate the sub-pixel 100. Substrates 114 and 116 surround liquid crystal material 104, pixel electrode 106 and common electrode 108. In one embodiment, the sub-pixel electrode 106 is located on the substrate 114 and the common electrode 108 is located on the substrate 116. In addition, the substrate 114 and the subpixel electrode layer include switching elements (not shown in FIG. 1). In one embodiment, the switching elements may be thin film transistors (TFTs). In another embodiment, the switching elements can be low temperature polysilicon.

The driver circuit 130 sends signals related to the sub-pixel values to the switching elements. In one embodiment, the drive circuit 130 uses low voltage differential signaling (LVDS) drivers. In another embodiment, a transistor-transistor logic (TTL) interface that senses both the rise and fall of the voltage is used in the drive circuit 130. In addition, timing controller 140 encodes the signals associated with the sub-pixel values into the signals required by the transmissions on the diagonal of the sub-pixels. Moreover, timing controller 140 has a memory to allow self-refresh of the LCD when signals associated with sub-pixels are removed from timing controller 140.

In one embodiment, spacers 118a and 118b are disposed on top of reflector 110 to maintain a uniform distance between substrates 114 and 116. Additionally, the sub-pixel 110 includes a first polarizer 120 and a second polarizer 122. In one embodiment, the axes of polarization of the first polarizer 120 and the second polarizer 122 are perpendicular to each other. In another embodiment, the axes of polarization of the first polarizer 120 and the second polarizer 122 are parallel to each other.

Sub-pixel 100 is illuminated by light source 102 or ambient light 124. The intensity of light passing through the sub-pixel 100 is determined by the potential difference between the sub-pixel electrode 106 and the common electrode 108. In an embodiment, when there is no potential difference applied between the sub-pixel electrode 106 and the common electrode 108, the liquid crystal material 104 is in a disoriented state and light passing through the first polarizer 120 is Blocked by the second polarizer 122. The liquid crystal material 104 is oriented when a potential difference is applied between the sub-pixel electrode 106 and the common electrode 108. The orientation of the liquid crystal material 104 allows light to pass through the second polarizer 122.

In an embodiment, the first reflective layer 160 may be disposed on one side of the electrode 106, while the second reflective layer 150 may be disposed on the opposite side of the electrode 106. The second reflective layer 150 may be made of metal and may be incident from the left-side of FIG. 1 until light 126 is transmitted through the transmitter 112 to illuminate the sub-pixel 100. ) Reflect or bounc the light 126 more than once.

For purposes of showing clear examples, the straight lines indicate the light path segments of the lights 112, 124. 126. Each optical path segment may include additional bending due to diffractions that may occur when the lights 112, 124. 126 move through the junction between the media of different refractive indices.

For purposes of showing clear examples, the sub-pixel 100 is described with two spacers 118a and 118b. In various embodiments, two neighboring spacers are spaced apart by one or more pixels, spaced every 10 pixels, spaced every 20 pixels, spaced every 100 pixels, or spaced apart by other distances. Can be arranged.

2 illustrates the placement of nine sub-pixels 100 of the LCD. The sub-pixel 100 includes a transmitter 112b and a reflector 110. In an embodiment, the transmitters 112a-c impart red, green and components respectively when followed by a (red-green-blue) RGB color system to form a color pixel. In addition, the transmitters 112a-c may impart other colors, such as red, green, blue and white or other color combinations. Moreover, the transmitters 113a and 114a give red color, the transmitters 113b and 114b give green color, and the transmitters 113c and 114c give blue color to the color pixel. In some embodiments, color filters 404a-c of different thicknesses may be disposed through the transmitters 112a-c to increase or decrease the saturation of the color imparted to the color pixel. Saturation is defined as the intensity of a gradation of a particular color in the visible spectrum. Furthermore, the colorless filter 202d may be disposed through the reflector 110. In various embodiments, the thickness of the colorless filter 202d may vary from zero to the thickness of the color filters 404a-c disposed through the transmissions 112a-c.

In an embodiment, the transmitter 112a represents a subpixel of one of the three colors of the color pixel. Similarly, transmitters 112b and 112c represent sub-pixels of the other two colors of the color pixel. In another embodiment, vertically oriented subpixels may be used to increase triple reflection and transflective resolution in the vertical direction as compared to the color transfer mode of operation. In another embodiment, the horizontal strips of subpixels can be used to increase triple reflection and transmissive resolution in the horizontal direction when compared to the color transfer mode.

The amount of light from the light source 102 transmitting through each of the transmitters 112a-c is determined by the switching elements (not shown in FIG. 1). The amount of light transmitted through each of the transmission units 112a-c, in order, determines the luminance of the color pixels. Moreover, the shape of the transmissions 112a-c and the color filters 404a-c may be hexagonal, square, octagonal, circular, or the like. Additionally, the shape of the reflector 110 may be rectangular, circular, octagonal, or the like.

In some embodiments, additional color filters may be disposed in the pixel 208 through the reflectors 110 of the sub-pixels 100. These additional color filters may be used to provide for compensating for colors that help to create a new monochrome white point for sub-pixels in the pixel 208 in monochrome operating mode. With a new monochrome white point, the pixel 208 Sub-pixels can be used to represent various shades of gray, collectively or individually.

For example, the color filter 206e may be used to cover the area of the reflector 110 in the sub-pixel 100 that includes the transmitter 112a. In some embodiments described in FIG. 2, the color filter 206e may include (1) the reflection portion 110 of the sub-pixel 100 that includes the transmission portion 112a (denoted red in this example). In addition to the part, the part of the reflector 110 may also be included in the sub-pixel including (2) the transmitter 112b (denoted green in this example). The color filter 206e may be used to impart blue to both the subpixels 100 that are given red and green in the pixel 208.

Similarly, the color filter 206f may be used to cover the area of the reflector 110 in the sub-pixel 100 that includes the transmitter 112c. In some embodiments as described in FIG. 2, the color filter 206f includes a reflector 110 in the sub-pixel 100 that includes (1) a transmitter 112c (denoted blue in this example). In addition to a portion of), a portion of the reflector 110 may also be included in the sub-pixel including (2) the transmitter 112d (denoted green in this example). The color filter 206f may be used to impart red to both the subpixels 100 imparted with blue and greens in the pixel 208.

The reflecting portion of the red sub-pixel 100 has an area covered by the red color filter 404a and another area covered by the blue filter 206e. The net result is that the sub-pixel can receive red and blue contributions from these areas covered by color filters 404a and 206e. The same is valid for the blue sub-pixels. However, the reflecting portion of the green sub-pixel 100 is covered by the first area covered by the green filter 404b, the second area covered by the blue filter 206e, and the third area covered by the red filter 206f. Has an area. In some embodiments, the first region may be smaller than one of the second and third regions or vice versa. In some embodiments, the second and third regions can be set to different sizes to create a solid colorless white point. The net result is that the green sub-pixel can receive the overall red and blue contribution from color filters 404b, 206e and 206f that can compensate for the green contribution for the purpose of creating a solid colorless white point.

  In some embodiments, as shown, these color filters 206e and 206f may cover a portion of the reflector 110 within the sub-pixel 100; Most of the reflector 110 in the sub-pixel 100 may be covered by the colorless filter 202d or may not be covered by the filters.

Embodiments may be configured to correct green hue and others. In various embodiments, the area covered by each of the color filters 404a-c may be the same as or larger than the area of each of the transmitters 112a-c. For example, the color filter 404a covering the transmitter 112a may have an area larger than that of the transmitter 112a. The same is valid for color filters 404b and 404c. In such embodiments, the color filters 404 and 206 of the sizes may be arranged or resized in some ways to produce a solid, colorless white spot.

In some embodiments, regions of sub-pixels 100 within pixel 208 may or may not be the same. For example, the area of the green sub-pixel 100 that includes the transmitter 112b is configured to be smaller than the areas of the red or green sub-pixel 100 that include the transmitter 112a or 112c. Can be.

In some embodiments, regions of color filters through transmitters 112a-c within pixel 208 may or may not be the same. For example, the area of the green filter 404b may be smaller than the areas of the red or blue filter 404a, 404c.

In some embodiments, regions of color filters through the reflector may or may not be the same. For example, the area of the blue filter 206e may be larger or smaller than the area of the red filter 206f.

In some embodiments, although (1) the areas of sub-pixels may be different from each other and / or (2) the areas covered by color filters 404a-c within pixel 208 may be different from each other, and And / or (3) reflections that are not covered by color filters in all sub-pixels of pixel 208, although the areas covered by color filters 206e and 206f in pixel 208 may be different. The areas are substantially the same. As used herein, the term "substantially the same" refers to differences within a small percentage. In some embodiments, the reflective areas are substantially the same if these reflective areas differ only within a certain range, such as <= 5%, for example.

3. Functional Summary

FIG. 3 illustrates the operation of sub-pixel 100 (eg, any sub-pixels 100 of FIG. 2) in the monochrome reflection mode. Since the embodiment of the monochromatic reflection is described with reference to Fig. 3, only the reflecting portion is shown in the figure.

The sub-pixel 100 can be used in monochromatic reflection mode in the presence of an external light source. In an embodiment, ambient light 124 passes through the layer of filters and the liquid crystal material 104 and is incident on the reflector 110. The layer of filters may include (1) a colorless filter 202d, (2) a color filter 404 (e.g., extending from an area opposite the transmission of sub-pixel 100 (e. 2, 404a of FIG. 2, and (3) color filter 206 (eg, 206e of FIG. 2), when the sub-pixel 100 is provided with the transmitter 112a in FIG. 2. . Some or all of the filters may be used to maintain the attenuation and path difference of ambient light 124 which is the same as the attenuation and path difference of light in the color transmission mode. The colorless color filter 202d may also be excluded by changing the design.

The reflector 110 of the sub-pixel 100 reflects the ambient light 124 to the substrate 116. In an embodiment, the potential difference v is applied to the sub-pixel electrode 106, which is electrically connected with the reflector 110 and the common electrode 108. The liquid crystal material 104 is directed, depending on the potential difference v. As a result, the orientation of the liquid crystal material 104 allows light to pass through the second polarizer 122, rotating the plane of ambient light 124. Therefore, the directivity angle of the liquid crystal material 104 determines the brightness of the sub-pixels and consequently the brightness of the sub-pixels 100.

In an embodiment, a normally white liquid crystal embodiment may be employed in the sub-pixel 100. In this embodiment, the axes of the first polarizer 120 and the second polarizer 122 are parallel to each other. The maximum threshold voltage is applied between the sub-pixel electrodes 106 to block light reflected by the reflector 110. The sub-pixel 100 therefore looks like black. In an embodiment, the axes of the first polarizer 120 and the second polarizer 122 are perpendicular to each other. The maximum threshold voltage may be applied between the sub-pixel electrode 106 and the common electrode 108 to illuminate the sub-pixel 110.

For the purpose of illustrating a clear example, the reflector 110 is shown as a smooth straight line. Alternatively, the reflector 110 may have a roughened or bumpy surface at the micron or sub-micron level.

4 illustrates the operation of the LCD in color transfer mode by using a partial color filter scheme. Since the color transmission embodiment is described, only the sub-pixel transmission unit 112a-c is shown in FIG. Over the substrate 116, as shown in FIG. 4, color filters 404a, 404b and 404c are disposed in the transmission sub-pixel portions 112a, 112b and 112c, respectively. Sub-pixel portions 112a, 112b and 112c refer to the sub-pixel optical value. Part 112a has light contributions from parts 102, 402, 120, 114, 106a, 104, 404a 108, 116 and 122. Part 112b has light contributions from parts 102, 402, 120, 114, 106b, 104, 404b, 108, 116, and 122. Part 112c has light contributions from parts 102, 402, 120, 114, 106c, 104, 404c, 108, 116, and 122. The color filters 404a, 404b, and 404c are also partially spread out on top of (or extending to part of) the reflective region of the sub-pixel. In various embodiments, the color filters cover less than half the amount of reflective area of the pixel (eg, 0% to 50% of the area) and in a particular embodiment the color filters cover about 0% of the area, In another particular embodiment the color filters cover 6% to 10% of the area and in still another particular embodiment the color filters cover 14% to 15% of the area.

The light source 102 is a reverse light source that provides light that can be collimated by using a light guide or lens. In an embodiment, light 402, coming from light source 102, passes through first polarizer 120. This aligns the plane 402 of light with respect to the particular plane. In an embodiment, the planes of light 402 are aligned in the horizontal direction. Additionally, the second polarizer 122 has an axis of polarization in the vertical direction. Transmitters 112a-c transmit light 402. In an embodiment, each of the transmitters 112a-c has a separate switching element. The switching element controls the intensity of the light 402 passing through the corresponding transmission.

Additionally, light 402 passes through liquid crystal material 104 after being transmitted through transmissions 112a-c. Transmitters 12a, 112b and 112c are provided with sub-pixel electrodes 106a-c, respectively. The potential difference applied between the sub-pixel electrodes 106a-c and the common electrode 108 determines the orientation of the liquid crystal material 104. The orientation of the liquid crystal material 104 in turn determines the intensity of light 402 incident on each color filter 404a-c.

In an embodiment, the green filter 404a may be disposed mostly or completely through the transmitter 112a and partially disposed in the reflector 110 (shown in FIGS. 2 and 3), and the blue filter 404b may transmit Most or fully disposed through portion 112b and partially disposed through reflecting portion 110 (shown in FIGS. 2 and 3), red filter 404c disposed most or completely through transmission portion 112c. And partly disposed in the reflector 110 (shown in FIGS. 2 and 3). Each of the color filters 404a-c gives a color corresponding to the color pixel. The colors imparted by the color filters 404a-c determine the chrominance value of the color pillsel. The color difference includes color information such as hue and saturation for the pixel. Furthermore, if ambient light 124 is present, the light reflected by reflector 110 (shown in FIGS. 2 and 3) provides illumination to the other pixels and compensates for the greenish appearance of the LC mode. It gives a monochromatic adjustment to the white reflectance. Therefore, such illumination increases the resolution in color transfer mode. Illumination is a measure of the brightness of a pixel.

As shown in FIG. 4, the transmitters 112a-c may have other cross-sectional areas (vertical directions are horizontal in FIG. 4). For example, the green transmitter 112b may have a smaller area than the red and blue transmitters 112a and 112c because green light may transmit more effectively in the sub-pixel 100 than lights of other colors. have. As shown in FIGS. 4, 5 and 6, the cross-sectional areas for the transmitters 112a-c may or may not be different in various embodiments.

5 illustrates the operation of an LCD in a color transfer mode by using a hybrid field sequential scheme, in accordance with various embodiments. Since the color transmission embodiment is described, only the transmission units 112a-c are shown in FIG. In an embodiment, the light source 102 comprises strips of LEDs, such as LED group 1, LED group 2, and the like (not shown). In an embodiment, the horizontally aligned LEDs are grouped together with one LED group at the bottom of the remaining LEDs to illuminate the LCD. Alternatively, vertically aligned LEDs can be grouped.

The groups of LEDs are illuminated in sequential form. The illumination frequency of the LED group can be 30 frames to 540 frames per second. In an embodiment, each LED group includes red LEDs 506a, white LEDs 506b, and blue LEDs 506c. Moreover, the red LEDs 506a and white LEDs 506b of LED group 1 are from time t = 0 to t = 5 and the red LEDs 506a and white LEDs 506b of LED group 2 are time t = 1 to t = 6 Similarly, all red and white LEDs of other LED groups function in sequential form. In an embodiment, where each group of LEDs is arranged vertically, each group of LEDs illuminates a horizontal row of pixels of the LCD. Similarly, the blue LEDs 506c and white LEDs 506b of LED group 1 are turned on from time t = 5 to t = 10 and the blue LEDs 506c and white LEDs of LED group 2 ( 506b) is turned on from time t = 6 to t = 11. Similarly, all blue and white LEDs of other LED groups are arranged in sequential form. The red LEDs 506a, white LEDs 506b and blue LEDs 506b have red LEDs 506a and blue LEDs 506b illuminating the transmitters 112a and 112c and the white LEDs 506b. ) Is aligned to illuminate the transmitter 112b. In another embodiment, the LED groups may include red, green and blue LEDs. The red, green and blue LEDs are arranged such that the green LEDs illuminate the transmitter 112b and the red and blue LEDs illuminate the transmitters 112a and 112c.

In an embodiment, light 502 from light source 102 passes through first polarizer 120. First polarizer 120 aligns the plane of light 502 with respect to a particular plane. In an embodiment, the plane of light 502 is aligned in the horizontal direction. Additionally, the second polarizer 122 has an axis of polarization at the vertical axis. Transmitters 112a-c transmit light 502. In an embodiment, each of the transmitters 112a-c has a separate switching element. Furthermore, the switching elements control the intensity of each color element, thereby controlling the intensity of light passing through each of the transmissions 112a-c. Furthermore, light 502 passes through liquid crystal material 104 after passing through transmissions 112a-c. Each of the transmitters 112a-c has its own sub-pixel electrode 106a-c. The potential difference applied between the sub-pixel electrodes 106a-c and the common electrode 108 determines the orientation of the liquid crystal material 104. In an embodiment where red, white, and blue LEDs are used, the orientation of the liquid crystal material 104 is, in order, the intensity of the light 502 incident on the green filter 504, and the transparent spacers 508a and 508b. Determine.

The intensity of the light 502 passing through the green filter 504 and the transparent spacers 508a and 508b determines the color difference value of the color pixel. In an embodiment, the green filter 504 is disposed corresponding to the transmitter 112b. The transmitters 112a and 112c do not have color filters. Alternatively, the transmitters 112a and 112c may use transparent spacers 508a and 508b, respectively. Green filter 504, transparent spacers 508a and 508b are positioned on top of substrate 116. In another embodiment, magenta color filters may be disposed on top of the transparent spacers 508a and 508b. In an embodiment, while time t = 0 and t = 5, when red LED 506a and white LED 506b are on, transmitters 112a and 112c are red and green filter 504 is Give green to the transmitter 112b. Similarly, while t = 11 at time t = 6, when blue LED 506c and white LED 506b are on, transmitters 112a and 112c are blue and green filter 504 is Give green to the transmitter 112b. The color imparted to the color pixel is formed by the combination of colors from the transmissions 112a-c. Moreover, if ambient light 124 is available, reflector 110 (shown in FIGS. 2 and 3) provides illumination for the color pixels. Therefore, this illumination increases the resolution in color transfer mode.

6 illustrates the operation of the LCD in the color transmission mode by using the diffraction scheme. Since the color transmission embodiment is described, only the transmission units 112a-c are shown in FIG. The light source 102 can be a standard reverse light source. In an embodiment, the light 602 from the light source 102 can be separated into a green element 602a, a blue element 602b, and a red element 602c by using another grating 604. Alternatively, the light 602 can be separated into a spectrum of colors having a different portion of the spectrum passing through each transmission 112a-c using a micro-light structure. In an embodiment, the micro-light structure is a thin film light structure with small lenses that can be stamped or imparted to the film. The green element 602a, the blue element 602b, and the red element 602c are directed to the transmissions 112a, 112b and 112c using the diffraction grating 604, respectively.

Moreover, light 602 components pass through first polarizer 120. This aligns the plane of the light components 602a-c with respect to the particular plane. In an embodiment, the planes of the light components 602a-c are aligned in the horizontal direction. Additionally, the second polarizer 122 has an axis of polarization in the vertical direction. The transmitters 112a-c allow the light components 602a-c to be transmitted through the transmitter. In an embodiment, each transmitter 112a-c has a separate switching element. The switching elements control the intensity of the light passing through the respective transmissions 112a-c, thereby controlling the intensity of the light component. Moreover, light components 602a-c pass through liquid crystal material 104 after passing through transmissions 112a-c. The transmitters 112a, 112b and 112c have pixel electrodes 106a, 106b and 106c, respectively. The potential difference applied between the pixel electrodes 106a-c and the common electrode 108 determines the orientation of the liquid crystal material 104. The orientation of the liquid crystal material 104, in order, determines the intensity of the light components 602a-c passing through the second polarizer 122. The intensity of the color elements passing through the second polarizer 122 determines the color difference of the color pixels in order. Moreover, if ambient light is available, the light reflected by reflector 110 (shown in FIGS. 2 and 3) provides illumination to the color pixels. Therefore, such illumination increases the resolution in the transmission mode.

As shown here, the presence of ambient light increases the illumination of the light pixels in the light transmission mode. Therefore, each pixel has both illumination and color difference. This increases the resolution of the LCD. As a result, the number of pixels required for a particular resolution is lower than in known LCDs, thus reducing the power consumption of the LCD. Moreover, transistor-transistor logic (TTL) based interfaces can be used to lower the power consumption of LCDs compared to the power consumed at interfaces used in known LCDs. In addition, because the timing controller stores signals related to pixel values, the LCD is optimized to take advantage of the self-refresh feature, reducing power consumption. In various embodiments, a lot of light and thin color filters that transmit less saturated colors may be used. Therefore, various embodiments facilitate the process of reducing power consumption when compared to existing LCDs.

Moreover, in the embodiment (described in FIG. 5), green or white light is always visually displayed in the sub-pixel 100, and only red and blue light are switched. Therefore, a low frame rate can be used compared to previously known field sequential displays.

 4. Driving Signal Technologies

In some embodiments, the pixels in the multi-mode LCD described herein may be used in color transfer mode in the same way as sub-pixels of standard color pixels. For example, three sub-pixels may be electrically driven by a multi-bit signal representing an RGB value (eg, a 24-bit signal) to produce the red, green, and blue component colors specified in the pixel. Can be.

In some embodiments, a pixel in the multi-mode LCD described herein may be used as a black-and-white pixel in a black-and-white reflection mode. In some embodiments, the three sub-pixels in the composite pixel of a multi-mode LCD are individually or alternatively collectively electrically connected by a single 1-bit signal that provides black or white to the sub-pixels. Can be driven. In some embodiments, each sub-pixel within a composite pixel within a pixel of a multi-mode LCD may be electrically driven by a different 1-bit signal to produce black or white at each sub-pixel individually. have. In these embodiments, power consumption is greatly reduced by (1) using 1-bit signals when compared to multi-bit signals in color transmission mode and / or (2) using ambient light as the main source of light. . In addition, in black-and-white reflection modes where each sub-pixel can be driven individually by a different bit value and each sub-pixel is an independent display unit of the display, The resolution may be such that the pixel is three times higher than the resolution of the LCD operating in other modes where the display unit is used as an independent display unit.

In some embodiments, the pixel in the multi-mode LCD described herein is used as a gray pixel (eg, in 2-bit-, 4-bit-, or 6-bit-gray-level reflection mode). Can be. In some embodiments, three sub-pixels in a pixel of a multi-mode LCD can be collectively electrically driven by a single multi-bit signal to provide gray shades to the pixel. In some embodiments, each sub-pixel within a pixel of a multi-mode LCD may be electrically driven by a different multi-bit signal to produce gray shades of each sub-pixel individually. Similar to the black-and-white mode of operation, in embodiments of these different gray-level reflection modes, the power consumption is (1) a smaller number of bits of the signal as compared to the multi-bit signals in the color transmission mode. And / or (2) using ambient light as the main source of light. In addition, in black-and-white reflection modes where each sub-pixel can be driven individually by a different bit value and each sub-pixel is an independent display unit of the display, The resolution may be such that the pixel is three times higher than the resolution of the LCD operating in other modes where the display unit is used as an independent display unit.

In some embodiments, the signal may be encoded into a video signal that instructs the display driver to drive in which mode of operation and at a corresponding resolution. A separate line may be used to inform the display to enter a low-power mode. Can be.

5. Low Field Rate Operations

In some embodiments, a low field rate can be used to reduce power consumption. In some embodiments, the driver IC for a multi-mode LCD may include electrons that can operate through slow moving liquid crystals and allow them to stay longer. In some embodiments, the metal layers 110, 150 and electrode layer 106 (which may be an oxide layer) may operate as additional capacitors to retain charge.

In some embodiments, a layer of liquid crystal material 104 having a high value of Δn, which refers to a thick LC material, may be used. For example, an LC material with Δn = 0.25 can be used. Such thick liquid crystals can switch states at low field rates and have high voltage holding ratios and long lifetimes even at low switching frequencies. In one embodiment, a 5CB liquid crystal material commercially available from Merck may be used.

The chipset 702 including the CPU (or controller) 708 may be part of the latched pixel drive circuit 400 described herein in the first timing control signal 712 at the LCD driver IC 704 or And output to the timing control logic 710, which may be added to the latched pixel driving circuit 400. The timing control logic 710 may then output the second timing control signal 704 to the multi-mode LCD 706. In some embodiments, chipset 702 may be a standard chipset that may be used to drive other types of LCD displays, including, but not limited to, multi-mode LCD 706 described herein.

In some embodiments, driver IC 704 may be inserted between chipset 702 and multi-mode LCD 706 and include specific logic to drive the multi-mode LCD in other modes of operation. The first timing control signal 712 can have a first frequency, such as 30 hertz, while the second timing control signal 714 is associated with the first frequency in a given operating mode of a multi-mode LCD. It may have a second frequency. In some embodiments, the second frequency can be configured or controlled to be half of the first frequency in reflection mode. As a result, the second timing control signal 714 received by the multi-mode display 706 may have a frequency lower than that for a standard LCD display in that mode. In some embodiments, the second frequency is adjusted by the timing control signal 710 to have different relationships from the first frequency depending on the operating modes of the multi-mode LCD 706. For example, in the color transmission mode, the second frequency may be the same as the first frequency.

In some embodiments, a pixel, such as pixel 208 of FIG. 2, may be formed substantially like a square while sub-pixels 100 may be formed like a rectangle with short sides of the rectangles arranged adjacent to each other. Can be. In such embodiments, the sub-pixel 100 may be directed in the direction of the long side of the rectangular shape. In some embodiments, the multi-mode LCD is substantially rectangular in shape. Sub-pixels in the LCD can be directed along the long or short side of the LCD rectangle.

For example, if a multi-mode LCD is mainly used for e-book applications, the multi-mode LCD may be a portrait mode with long sides in the vertical (or upward) direction. The sub-pixel 100 can be configured to direct in the long side direction of the multi-mode display. Multi-mode LCDs, on the other hand, are used in a variety of other applications such as video, reading, the Internet, and gaming, while multi-mode LCDs can be used in landscape modes with long sides in the horizontal direction. The sub-pixels 100 can be configured to orient in the short side direction of the multi-mode display. Thus, the orientation of sub-pixels in a multi-mode LCD display can be set to be the same as the method for improving the readability and resolution of the contents in main use.

6. Extensions and variations

While the preferred embodiments of the invention have been shown and described, it will be clear that the invention is not limited to these embodiments. Various modifications, changes, variations, substitutions and equivalents are within the scope of the invention without departing from the spirit and scope of the invention as set forth in the claims. It will be apparent to those of ordinary skill in the art.

Claims (30)

A multi-mode liquid crystal display comprising a plurality of pixels,
Each pixel includes a plurality of sub-pixels, and the sub-pixels in the plurality of sub-pixels are:
A first polarization layer having a first polarization axis;
A second polarization layer having a second polarization axis;
A first substrate layer and a second substrate layer opposite to the first substrate layer, wherein the first substrate layer and the second substrate layer are interposed between the first polarization layer and the second polarization layer; Inserted －;
A liquid crystal material between the first substrate layer and the second substrate layer;
A first reflective layer adjacent to the first substrate layer, the first reflective layer comprising at least one opening forming part of a transmisive part of the sub-pixel, wherein the first reflective layer The remainder forms part of the reflective part of the sub-pixel;
A first filter of a first color facing the transmitter and covering the transmitter, the first filter having an area wider than that of the transmitter; And
And a second filter of a second color facing said reflecting portion and partially covering said reflecting portion, said second color being different from said first color. The method according to claim 1,
A first side of the display is located on a first side of the second substrate layer, and the first reflective layer is located on a second side, which is the other side of the second substrate layer, the first side of the first reflective layer And a light source for providing light at a second side opposite the display through at least one opening. The method of claim 2,
And a diffractive grating or micro-optical film configured to disperse light from the light of the light source into a spectrum of color. The method according to claim 1,
And the cross-sectional area of the reflecting portion of the sub-pixel is over half of the total cross-sectional area of the sub-pixel. The method according to claim 1,
The second filter of the second color extends over an area of another sub-pixel, and partially covers an area of the other sub-pixel. The method according to claim 1,
A third filter of a third color opposite the reflecting portion of the sub-pixel and partially covering another area of the reflecting portion, wherein the third color is different from both the first and second colors; Multi-mode liquid crystal display. The method according to claim 1,
A reflection mode that is not covered by color filters in all sub-pixels of the pixel is substantially the same. The method according to claim 1,
And the first reflective layer comprises a metal. The method of claim 6,
Further comprising a first electrode layer adjacent to the first substrate layer and a second electrode layer adjacent to the second substrate layer,
And the liquid crystal material is interposed between the first electrode layer and the second electrode layer. 10. The method of claim 9,
And the first electrode layer is an oxide layer. The method according to claim 1,
Further comprising a second reflective layer on the opposite side of the first electrode layer, while the first reflective layer is on one side of the first electrode layer,
And the second reflective layer includes at least one opening that is part of the transmission portion of the sub-pixel. The method according to claim 1,
Wherein the first and second color filters are configured to shift a monochrome white point for the sub-pixel. The method according to claim 1,
And the transmission portion occupies an interior part of the cross section of the sub-pixel. The method according to claim 1,
And the first and second color-filters have different thicknesses. The method according to claim 1,
And the first and second color-filters have the same thickness. The method according to claim 1,
Further comprising one or more colorless spacers on top of the reflecting portion. The method of claim 16,
And the one or more colorless spacers have the same thickness. The method of claim 16,
And the one or more colorless spacers have different thicknesses. The method of claim 17,
Further comprising a driving circuit configured to provide pixel driving signals to the plurality of switching elements,
And the plurality of switching elements determine an intensity of light transmitted through the transmitter. The method of claim 19,
And the drive circuit further comprises a transistor-transistor-logic (TTL) interface. The method of claim 19,
And a timing control circuit configured to refresh the pixel values of the multi-mode liquid crystal display. The method according to claim 1,
1% to 50% of the reflectors have color filters. As a computer,
One or more processors; And
A multi-mode liquid crystal display coupled to the one or more processors, the multi-mode liquid crystal display comprising a plurality of pixels, each pixel comprising a plurality of sub-pixels, wherein the sub pixel in the plurality of sub-pixels is:
A first polarization layer having a first polarization axis;
A second polarization layer having a second polarization axis;
A first substrate layer and a second substrate layer opposite to the first substrate layer, wherein the first substrate layer and the second substrate layer are between the first polarization layer and the second polarization layer; Inserted in －;
A liquid crystal material between the first and second substrate layers;
A first reflective layer adjacent to the first substrate layer, the first reflective layer comprising at least one opening forming part of a transmisive part of the sub-pixel, wherein the first reflective layer The remainder forms part of the reflective part of the sub-pixel;
A first filter of a first color facing the transmitter and covering the transmitter, the first filter having an area wider than that of the transmitter; And
A second filter of a second color opposite the reflecting portion and partially covering the reflecting portion, the second color being different from the first color. 24. The method of claim 23,
A first side of the display is located on a first side of the second substrate layer, and the first reflective layer is located on a second side, which is the other side of the second substrate layer, the first side of the first reflective layer And a light source for providing light at a second side opposite the display, through at least one opening. 24. The method of claim 23,
And the reflective regions not covered by the color filters within all sub-pixels of the pixel are substantially the same. 24. The method of claim 23,
And the first reflective layer comprises a metal. 24. The method of claim 23,
Further comprising a second reflective layer on the opposite side of the first electrode layer, while the first reflective layer is on one side of the first electrode layer,
And the second reflective layer includes at least one opening that is part of the transmission portion of the sub-pixel. 24. The method of claim 23,
A second reflective layer adjacent the first reflective layer on an opposite side of the first substrate layer,
And the second reflective layer includes at least one opening that is part of the transmission portion of the sub-pixel. 24. The method of claim 23,
And one or more colorless spacers on top of the reflecting portion. 24. The method of claim 23,
Further comprising a driving circuit configured to provide pixel driving signals to the plurality of switching elements,
And the plurality of switching elements determine an intensity of light transmitted through the transmission unit.

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