CN1998041A - Color flat panel display for sub-pixel rendering with split blue sub-pixels - Google Patents

Abstract

This invention discloses various embodiments of an eight-subpixel group, which can be composed of three-color (red, green, and blue) subpixels, each with a colored blue subpixel. In the eight-subpixel group, the number of the colored blue subpixels is twice that of the red and green subpixels. This invention also discloses various embodiments of subpixel coloring applied to the subpixel group.

Description

Color flat panel display with subpixel rendering with split blue subpixels

technical field

This application relates to improvements in display design, in particular to improvements in the arrangement of color pixels, addressing methods used in displays, and methods for converting display data formats.

Background technique

The full color perception in the eye is produced by three types of color photosensitive nerve cells called "cones". These three types of photoreceptor cells are sensitive to different wavelengths of visible light: long, medium and short (corresponding to "red", "green" and "blue", respectively). The relative densities of these three photoreceptor cells are significantly different from each other. There are slightly more red photoreceptors than green photoreceptors. There are very few blue photoreceptors compared to red photoreceptors or green photoreceptors.

Contents of the invention

The sensory channels that the human visual system processes information detected by the eyes include: luminance, chroma, and motion. Motion is only important to the imaging system designer for the flicker threshold. The luminance channel only receives input from red and green photoreceptors and is therefore "colorblind". The luma channel processes information in such a way that the contrast of edges can be enhanced. The chroma channel has no edge contrast enhancement. Since the luma channel uses and enhances every red and green photoreceptor cell, the resolution of the luma channel is several times higher than that of the chroma channel. Blue photoreceptors contribute negligibly to brightness perception. The luminance channel thus acts like a resolution bandpass filter. Peak response occurs at 35 cycles/degree (cycle/0). It limits the response at 0 cycles/degree and 50 cycles/degree on the horizontal and vertical axes. This means that the luminance channel can only distinguish the relative luminance between two areas in the field of view, but not the absolute luminance. Also, if a detail exceeds 50 cycles/degree, it will be blended together. The limits on the horizontal axis are slightly higher than those on the vertical axis. The limit on the oblique axis is lower.

The chroma channel can be further divided into two sub-channels, so we can see the full range of colors. These channels are completely different from the luma channel, they are equivalent to two low pass filters. One of them can distinguish the color of an object at any time, no matter how big the object is in our field of vision. The red/green chroma subchannel resolution limit is 8 cycles/degree, and the yellow/blue chroma subchannel resolution is 4 cycles/degree. Thus, to most careful viewers, the errors caused by the octave-low red/green or yellow/blue resolution are barely noticeable, as if not at all, as Xerox and NASA, Ames Research Center As confirmed by the experiments (see R. Martin, J. Gine, J. Madmer, Detectability of Reduced Blue Pixel Count in Projection Displays, SID Digest 1993).

The luminance channel determines image detail by analyzing the spatial frequency Fourier transform components. With the help of signal theory, any known signal can be represented as the sum of a series of sine waves of different amplitudes and frequencies. From an arithmetic point of view, this process of clarifying the sine wave component of a known signal is called Fourier transform. The human visual system responds to these sinusoidal components on a two-dimensional image signal.

Color perception is affected by an effect known as "assimilation" or the Von Bezold color mixing effect. This is why separate pixels (or sub-pixels or emitters) on a display can be perceived as mixed colors. Color mixing effects occur at a given angular distance in the field of view. Because of the relative rarity of blue photoreceptors, color mixing occurs at a greater angular distance for blue photoreceptors than for red or green. This distance is about 0.25° for blue and about 0.12° for red or green. At a viewing distance of 12 inches, 0.25° is equivalent to 50 mils (1,270 μ) on the monitor. Therefore, if the blue subpixel pitch is less than half of the mixing pitch (625μ), the colors can be mixed without loss of image quality. This mixing effect is directly related to the chroma subchannel resolution limit described above. Below the resolution limit, you can see separated colors, and above the resolution limit, you can see mixed colors.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various implementations and embodiments.

Figure 1 shows one method of ordering subpixel emitters, which are grouped into groups of three colors—red, green, and blue. These groups generate a larger group of 8 sub-pixels that repeat linearly, where the blue sub-pixel is "split".

Figures 2, 3, and 4 show an embodiment of sorting red, green, and blue resampling regions for the red, green, and blue planes, respectively. This ordering matches the subpixel arrangement shown in Figure 1.

Figures 5 and 6 show the arrangement of the red and green resampling regions of Figures 2 and 3 respectively, which are superimposed on the sub-pixel arrangement of Figure 1 .

Figure 7 shows a specific inter-color-plane-phase relationship between the red and green resampled regions superimposed on the sub-pixel arrangement shown in Figure 1 .

8A and 8B show two possible schemes of driver arrangements for the color emitter subpixel arrangement shown in FIG. 1 .

Figures 9 and 10 show two "dot inversion" schemes that match the scheme of Figure 8A - commonly referred to as "2x1" and "1x1" respectively.

Figures 11 and 13 show an alternative blue slab resampling area arrangement that can replace the arrangement shown in Figure 4 .

Figures 12 and 14 illustrate how the corresponding blue slab resampling regions shown in Figures 11 and 13 are mapped onto the sub-pixel arrangement shown in Figure 1 .

Figures 15 and 16 show two "dot inversion" schemes that match the scheme shown in Figure 8B - commonly referred to as "2x1" and "1x1" respectively.

Figure 17 shows the result of switching on two full-color incoming data pixels.

Figures 18A and 18B illustrate other embodiments of sub-pixel ordering in groups of eight where the sub-pixel vertical displacements are different.

Figures 19A and 19B illustrate other embodiments of subpixel ordering in groups of eight where the displacements of the majority of subpixels split within a subpixel group are different.

FIG. 20 depicts a system including a subpixel rendering technique device suitable for driving a display panel made according to the embodiments described herein.

Detailed ways

This section describes various implementation forms and embodiments in detail, and some examples have been mentioned in the description of the drawings. Wherever possible, the same reference number will be used throughout the specification to refer to the same or like parts.

In FIG. 1, in the arrangement of sub-pixel light emitters 100, there are three-color light emitters in group 120, and these groups form a larger linear replication unit composed of 8 sub-pixels. This design is described in the '738 provisional application, which is hereby incorporated by reference. Group 120 is composed of red subpixel 104 , green subpixel 106 and blue subpixel 102 . It is not difficult to see that the blue sub-pixel 102 is "split"---that is, its width along the horizontal axis is smaller than that of the red and green sub-pixels, but the number of sub-pixels per group or per replication unit is double times. Such a "split" sub-pixel may refer to a sub-pixel that has a smaller area than a non-split sub-pixel. Splitting the blue subpixel helps to dissipate the noticeable effect of the visible vertical blue bands that appear in the display. This is further discussed in US Patent Application Serial No. 10/278,328 (the '328 application). The patent application titled "Improvement in Subpixel Arrangement and Design for Color Flat Panel Display with Simplified Blue Brightness and Good Visibility" was filed on October 22, 2002, which is hereby incorporated by reference.

It can also be seen from Figure 1 that the red and green sub-pixels are placed on a "checkered disk" with a replica of the cell itself. It is further discussed in the '328 application that it is possible to have a split green sub-pixel at sub-pixel location 102 by changing the color of the replicated cell group 120, and the remaining red and blue sub-pixels form a checkerboard pattern. Likewise, the red subpixel is expected to be split, with the green and blue subpixels placed on a checkered disk. Another "checkered disk" of this illuminant is similar to the red and green "checkered disk" disclosed in U.S. Patent Application Serial No. 09/916,232, "Method of Color Pixel Arrangement for a Full-Color Imaging Device with Simplified Labeling" , which was filed on July 28, 2000, which is hereby incorporated by reference.

It should be noted that while FIG. 1 depicts a "split" blue sub-pixel that is narrower than both red and green sub-pixels, another embodiment of the present invention uses pixels. To achieve a satisfactory white point when all subpixels are on within a logical pixel, the relative intensities of the red, green, and blue emitters can be varied appropriately, as described in U.S. Patent Application Serial No. 10/243,094, "For Subpixel Coloring This is discussed in "Improved four-color arrangement method of illuminants", which was filed on September 13, 2002, and is hereby incorporated by reference.

As shown in FIG. 1, the sub-pixels are generally rectangular. It should be noted that other shapes of sub-pixels are possible and are contemplated within the scope of the present invention. For example, numerous other regular and irregular shapes of sub-pixels are possible if they can be produced. The approach described here can be used to annotate subpixel rendering (SPR), but only if there is a combination of 8 colored subpixels in the approach.

Since the shapes of the sub-pixels within the scope of the present invention can be varied, the exact positions of the sub-pixels within the scope of the present invention can also be varied. For example, FIGS. 18A and 18B depict a similar group of 8 sub-pixels in which one or both majority bars 102 are displaced (relatively or otherwise) to sub-pixels 104 and 106 . Other vertical displacements are also possible.

Other representations of groupings of 8 are also possible. 19A and 19B depict a group of 8 with a majority of sub-pixels 102 interspersed on a checkered disk of sub-pixels 104 and 106 . Other arrangements of most sub-pixel positions within such a grid are possible and within the scope of the invention.

Figures 19A and 19B may have cylindrical electrodes zigzag across the display. Compared to an RGB stripe system with the same resolution, the columnar driver savings should be 1/3, and the number of sub-pixels should be about 2/3 of that of the RGB stripe system.

Other embodiments of the invention are also possible. For example, an entire group of 8 subpixels can be rotated 90 degrees to reverse the effect of the row and column drivers connected to the group. A co-pending application entitled "Color Display with Horizontal Subpixel Arrangement and Design," which is incorporated herein by reference, discloses such a method for horizontal subpixel arrangement.

Another illuminant "checkered disc" is similar to the red and green "checkered disc" disclosed in co-pending and commonly assigned US Patent Application Serial No. 09/916,232 (the '232 application). The patent application, entitled "Arrangement of Color Pixels for a Full-Color Imaging Device with Simplified Addressing," was filed on July 25, 2001, which is incorporated herein by reference.

Since the display essentially consists of a replica unit 120 with blue sub-pixels split into sub-pixels 102, it is possible to implement sub-pixel coloring on this display using area resampling techniques. This technique is disclosed in U.S. Patent Application Serial No. 10/150,355, entitled "Method and System for Subpixel Shading Using Gamma Adjustment," filed May 17, 2002, which is hereby incorporated by reference and incorporated herein by reference. jointly owned by the same assignee of the application. Figures 2 to 7 illustrate one embodiment of region resampling.

Figures 2, 3 and 4 show the red 200, green 300 and blue 400 resampling area arrangements for the red, green and blue planes respectively. It should be noted that each color resampling region arrangement 200, 300 and 400 is composed of resampling regions 206, 306 and 404, and each resampling region has associated resampling points 202, 302 and 402 respectively. Within each color plane, resampling points 202, 302, and 402 are matched to red 104, green 106, and blue 102 subpixel positions, respectively, and their exact intercolor plane phase relationships are not necessary. The number of phase relationships is arbitrary, and a large number of phase relationships have properties useful in known data format conversions.

5 and 6 show the red and green resampling region arrangements of FIGS. 2 and 3 overlaid on the subpixel arrangement 100 shown in FIG. 1 . FIG. 7 illustrates a specific intercolor plane phase relationship between the red and green resampled regions overlaid on the subpixel ordering 100 . This particular relationship depicts a transition from the traditional fully converging square grid red, green, blue RGB format, which will be displayed "one-to-one" with a square blue 102 sub-pixel grid. In this intercolor plane phase relationship, the green 300 , blue 400 , and red 200 resampling regions are arranged so that the red 202 and green 302 resampling points coincide with the blue 402 sampling points. This makes the blue sub-pixel 102 appear to be on top of, or closely related to, the red 104 and green 106 sub-pixel checkerboards.

Figures 11 and 13 show another arrangement of blue plane resampling regions, which can replace the arrangement shown in Figure 4 . Figures 12 and 14 illustrate how these blue plane resampling regions are mapped onto the sub-pixel arrangement shown in Figure 1, respectively. Figures 11 and 13 depict two different embodiments of the resampling region 406 for blue with the phase shifts shown. It should be pointed out that other phase shifts can also satisfy the intent of the present invention. Additionally, other resampling regions for blue pixel data may also be used within the scope of the invention.

These diagrams are only explanatory, and only assist in understanding the relationship between resampling points, reconstruction points, resampling regions and sub-pixel positions in this embodiment.

The subpixel rendering techniques described in the '355 patent application can be used to convert the incoming data format into a format suitable for the display. The method is as follows: (1) Determine the implicit sampling area of each data point that introduces three-color pixel data; (2) Determine the resampling area of each color sub-pixel in the display; (3) Get the coefficient of each resampling area , the coefficient is composed of fractions, the denominator of the fraction is a function of the resampling area, the numerator is a function of the area of each implied sampling area mentioned above, and the implied sampling area may partially overlap with the resampling area; (4) each implied sampling area The imported pixel data is multiplied by the coefficient to obtain the product; (5) adding each product to obtain the brightness value of each resampling area.

Other subpixel rendering techniques can also be employed with the various subpixel arrangements disclosed herein. For example, the known "adaptive filtering" technique can be used in this manner and is described in US Patent Application Serial No. 10/215,843 "Method and System for Sub-Pixel Shading with Adaptive Filtering", issued in 2002 Filed August 8, which is incorporated herein by reference and is commonly owned by the same assignee as this application. Adaptive filtering does not require the sampling of the input data to reach 3×3, and the minimum value of the two-line memory is used. The quiz can use smaller samples of the input data, such as 1x3 or 1x2 matrices. Input data is sampled for testing for vertical or diagonal lines, dots, edges, or other high-contrast details, and action is taken according to the test structure.

An inspection template can be used and compared to the image data to check whether an edge is detected; if so, take appropriate action on the red and/or blue data - such as applying gamma or applying a new value or a different filter. Optical factor. Otherwise, if no signatures are detected, no action is necessary.

Figure 17 illustrates the result of interfacing two full-color input data pixels. Two pixels are converted into two groups of sub-pixels connected with different amplitudes, called "logical pixels". The left logical pixel is located at or near the center of the green sub-pixel 106 . The right subpixel is located at or near the center of red subpixel 104 . Of these two logical pixels, different sub-pixels are connected to the appropriate brightness so that a pleasing white color can be formed and centered on a green or red sub-pixel.

8A and 8B show two possible diagrams of a driver arrangement 800 for the color emitter subpixel arrangement shown in FIG. 1 . FIG. 8A shows a one-to-one correspondence of column drivers to columns in a display; however, with split blue sub-pixels, adjacent columns of split blue sub-pixels can be linked by tie 820 . As shown in Figure 8B, this pattern is advantageous for saving the number of column drivers.

For convenience, the example shown has the same number of sub-pixels as shown in FIG. 1 . Since component 810 can represent one or a few electronic components, these drive arrangements can be used in a wide variety of display technologies. They may represent capacitive display elements for passively addressed liquid crystal displays (LCD) or electroluminescent displays (EL). It can also represent the gaseous discharge element in the plasma display panel (PDP), the semiconductor diode element of the passive inorganic light-emitting diode or organic light-emitting diode display, the transistor, accumulator and capacitor element of the active matrix liquid crystal display (AMLCD), and also Represents the multiple transistors, accumulators and light emitting elements of an Active Matrix Organic Light Emitting Diode Display (AMOLED). In general, color sub-pixels and their associated electronics may be represented in other known or yet-to-be-invented display technologies.

Known drive timings and methods can be used for the NXM drive matrix described above. However, specific color selections will need to be made, especially to adjust for color variations across a grid of plates or within a single column. For example, techniques known in the art such as "multi-row addressing" or "multi-line addressing" in passive liquid crystal displays can be modified to limit the grouping of rows to odd and even row combinations. This will reduce the potential for cross-color interference, because only one color at a time will be marked within a column of two sub-pixels of alternating colors.

An inversion scheme can be used in the unique subpixel arrangement described above, which reverses the polarity of the electric field across the display cell to provide a time-averaged zero-time pure field and ionic current across the cell. Figures 9 and 10 (matching the scheme of Figure 8A) and Figures 15 and 16 (matching the scheme of Figure 8B) show two "dot inversion" schemes --- active matrix respectively "2×1" and "1×1" on the LCD display, both of these patterns can achieve good results. The graphs shown in Figures 9 and 15 work better when there is an imbalance of light emission between positive and negative electrodes, especially when the eye is tracking the movement of a picture displayed on the screen. Each graph shows half of the display labeled fields with polarity and the other half with the opposite polarity. Alternating these fields results in pure zero current (zero DC bias), as is well known in the art.

FIG. 20 depicts a system 2000 in which displays made according to various embodiments disclosed in this specification are driven by a subpixel rendering technique 2004 , which can be maintained on a physical device 2002 . An input image data stream 2008 may be input to subpixel shading technique 2004 and transformed in the manner disclosed herein. An output image data stream 2010 is sent to the display device 2006 to drive various sub-pixels to form an image. As noted in several references cited herein, subpixel rendering (SPR) techniques 2004 may be implemented in hardware and/or software, or a combination of both. For example, the subpixel rendering technique 2004 may reside as logic (hardware or software) on the display, or on a graphics controller chip or plug-in board.

While the invention has been described with reference to exemplary embodiments, it will be readily understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof within the scope of the invention. In addition, numerous adaptations may be made to adapt a particular situation or material to the spirit without departing from the scope of the invention. For example, some of the embodiments described above can be implemented on other display technologies such as organic light emitting diodes (OLED), electroluminescent displays (EL), electrophoretic displays, active matrix liquid crystal displays (AMLCD), passive matrix liquid crystal displays (PMLCD) ), incandescent displays, solid-state light-emitting diodes (LEDs), plasma panel displays (PDPs), and flash displays. Therefore, the invention should not be limited to the particular embodiment disclosed as the best mode directed to this invention, but will include all embodiments falling within the scope of the appended claims.

Claims (30)

1. The display is composed of a large number of sub-pixel groups; the sub-pixel group is composed of 8 sub-pixels; Wherein each sub-pixel refers to one of the red sub-pixel, green sub-pixel and blue sub-pixel; Wherein the sub-pixel group is composed of 4 blue sub-pixels, 2 red sub-pixels and 2 green sub-pixels; Wherein the red and green sub-pixels generally form a checkerboard pattern. 2. The display of claim 1, wherein the blue sub-pixel comprises a smaller area than the red and green sub-pixels. 3. The display of claim 1, wherein said group of subpixels further comprises two rows and four columns of subpixels; and wherein a first set of two non-adjacent columns comprises four of said blue subpixels, the first Two sets of two non-adjacent columns include two of the red sub-pixels and two of the green sub-pixels. 4. The display of claim 3, wherein said two non-adjacent columns containing four of said blue subpixels are opposite to said two non-adjacent columns containing two of said red subpixels and two of said green subpixels. The two non-adjacent columns are vertically shifted. 5. The display of claim 1, wherein said blue sub-pixels are interspersed within said checkerboard pattern formed by said red and green sub-pixels. 6. The display of claim 1, wherein said display is an active matrix liquid crystal display. 7. The display of claim 6, wherein the display employs a dot inversion pattern to drive the subpixels of each subpixel group. 8. The display of claim 7, wherein said dot inversion pattern is 1x1 dot inversion. 9. The display of claim 7, wherein said dot inversion pattern is 2x1 dot inversion. 10. In a display, the display includes a large number of sub-pixel groups; the sub-pixel group further includes 8 sub-pixels; wherein each of the sub-pixels refers to a blue sub-pixel, a red sub-pixel and a green sub-pixel one of the pixels; wherein said sub-pixel group further includes four said blue sub-pixels, two said red sub-pixels and two said green sub-pixels; wherein said red sub-pixels and The green sub-pixels substantially form a checkerboard pattern; A method of converting source pixel data in a rendered native format to said display comprises: Determining the implied sampling area for each data point that introduces three-color pixel data; determining the resampling area for each color subpixel in the display; yields a set of coefficients for each resampling region consisting of fractions whose denominator is a function of the resampling region and whose numerator is a function of the area of each implied sampling region, which may differ from the resampling region part coincide; Multiply the incoming pixel data of each implicit sampling area with the coefficient to obtain the product; The individual products are summed to obtain a brightness value for each resampled region. 11. The method of claim 10, wherein determining the resampling region further comprises: A phase relationship between the resampled regions of each color subpixel is determined. 12. The method of claim 11, wherein determining the phase relationship further comprises: The positions of the resampling points of each of the color resampling regions are determined so that the red and the green resampling points can substantially cover the blue resampling points. 13. In a display, the display includes a large number of sub-pixel groups; the sub-pixel group further includes 8 sub-pixels; wherein each of the sub-pixels is a blue sub-pixel, a red sub-pixel and a green sub-pixel one of them; wherein said sub-pixel group further includes four said blue sub-pixels, two said red sub-pixels and two said green sub-pixels; wherein said red sub-pixels and said The green sub-pixels generally form a grid pattern; A method of converting source pixel data in a rendered native format to said display comprises: Input a set of color image data; Validate input data under numerous conditions; and Appropriate action is taken on the results of the verification of said input data. 14. The method of claim 13, wherein said set of color image input data comprises a 1x3 matrix of samples of input data. 15. The method of claim 13, wherein said set of color image input data comprises a 1x2 matrix of samples of input data. 16. The method of claim 13, wherein validating input data under a plurality of conditions further comprises: Detect high-contrast features in input data. 17. The method of claim 16, wherein said high-contrast feature comprises one of a group consisting of edges, lines and points. 18. The method of claim 13, wherein taking appropriate action on the results of said verification of input data further comprises: Replaces the current color data value with a new color data value. 19. The method of claim 13, wherein taking appropriate action on the results of said verification of input data further comprises: Applies gamma correction to the current color data values. 20. The method of claim 13, wherein taking appropriate action on the results of said verification of input data further comprises: Applies new subpixel shading filter coefficients to the input data. 21. A system includes: A display, the display includes a large number of sub-pixel groups; the sub-pixel group further includes 8 sub-pixels; wherein each of the sub-pixels is one of a blue sub-pixel, a red sub-pixel and a green sub-pixel; Wherein said sub-pixel group further includes four said blue sub-pixels, two said red sub-pixels and two said green sub-pixels; wherein said red sub-pixels and said green sub-pixels A checkerboard pattern is generally constituted; and a method of subpixel rendering input image data. 22. The system of claim 21, wherein said means for subpixel rendering input data further comprises: means for inputting a set of color image data; means of detecting incoming data under a variety of conditions; and Means for taking appropriate action on the result of said verification of the input data. 23. The system of claim 22, wherein said set of color image input data comprises a 1x3 matrix of samples of input data. 24. The system of claim 22, wherein said set of color image input data comprises a 1x2 matrix of samples of input data. 25. The system of claim 22, wherein said means for checking input data under a plurality of conditions further comprises: A device for detecting high-contrast features in input data. 26. The system of claim 25, wherein said high contrast features comprise one of a group consisting of edges, lines and dots. 27. The system of claim 22, wherein said means for taking appropriate action on the results of said verification of input data further comprises: Means for replacing the current color data value with a new color data value. 28. The system of claim 22, wherein said means for taking appropriate action on the results of said verification of input data further comprises: A device that applies a gamma correction to the current color data value. 29. The system of claim 22, wherein said method of taking appropriate action on the results of said verification of input data further comprises: Means for applying new subpixel shading filter coefficients to input data. 30. The system of claim 21, wherein said means for subpixel rendering input data further comprises: means for determining an implied sampling area for each data point into which the three-color pixel data is incorporated; means for determining a resampling area for each color subpixel in the display; means for deriving said set of coefficients for each resampling region, said coefficients consisting of fractions whose denominator is a function of the resampling region and whose numerator is a function of the area of each implied sampling region, which may differ from The resampling area partially overlaps; means for multiplying incoming pixel data for each implied sampling region by a coefficient to obtain a product; A device that adds the individual products to obtain the brightness value for each resampled region.

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