WO2014038122A1 - Procédé d'éclairage d'un dispositif d'affichage - Google Patents

Procédé d'éclairage d'un dispositif d'affichage Download PDF

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Publication number
WO2014038122A1
WO2014038122A1 PCT/JP2013/004427 JP2013004427W WO2014038122A1 WO 2014038122 A1 WO2014038122 A1 WO 2014038122A1 JP 2013004427 W JP2013004427 W JP 2013004427W WO 2014038122 A1 WO2014038122 A1 WO 2014038122A1
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Prior art keywords
light
display
light source
blue
led
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PCT/JP2013/004427
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English (en)
Inventor
Xiao-Fan Feng
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Sharp Kabushiki Kaisha
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Priority claimed from US13/604,578 external-priority patent/US9082349B2/en
Application filed by Sharp Kabushiki Kaisha filed Critical Sharp Kabushiki Kaisha
Publication of WO2014038122A1 publication Critical patent/WO2014038122A1/fr

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/3413—Details of control of colour illumination sources
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0209—Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0271—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
    • G09G2320/0276—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
    • G09G3/3426—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines the different display panel areas being distributed in two dimensions, e.g. matrix

Definitions

  • the present invention relates to backlit displays and, more particularly, to a backlit display with improved color.
  • the local transmittance of a liquid crystal display (LCD) panel or a liquid crystal on silicon (LCOS) display can be varied to modulate the intensity of light passing from a backlit source through an area of the panel to produce a pixel that can be displayed at a variable intensity. Whether light from the source passes through the panel to an observer or is blocked is determined by the orientations of molecules of liquid crystals in a light valve.
  • LCD liquid crystal display
  • LCOS liquid crystal on silicon
  • LCD panels used for computer displays and video screens are typically backlit with flourescent tubes or arrays of light-emitting diodes (LEDs) that are built into the sides or back of the panel.
  • LEDs light-emitting diodes
  • the transmittance of the light valve is controlled by a layer of liquid crystals interposed between a pair of polarizers.
  • Light from the source impinging on the first polarizer comprises electromagnetic waves vibrating in a plurality of planes. Only that portion of the light vibrating in the plane of the optical axis of a polarizer can pass through the polarizer.
  • the optical axes of the first and second polarizers are arranged at an angle so that light passing through the first polarizer would normally be blocked from passing through the second polarizer in the series.
  • a layer of translucent liquid crystals occupies a cell gap separating the two polarizers.
  • the physical orientation of the molecules of liquid crystal can be controlled and the plane of vibration of light transiting the columns of molecules spanning the layer can be rotated to either align or not align with the optical axes of the polarizers.
  • the surfaces of the first and second polarizers forming the walls of the cell gap are grooved so that the molecules of liquid crystal immediately adjacent to the cell gap walls will align with the grooves and, thereby, be aligned with the optical axis of the respective polarizer.
  • Molecular forces cause adjacent liquid crystal molecules to attempt to align with their neighbors with the result that the orientation of the molecules in the column spanning the cell gap twist over the length of the column.
  • the plane of vibration of light transiting the column of molecules will be "twisted" from the optical axis of the first polarizer to that of the second polarizer. With the liquid crystals in this orientation, light from the source can pass through the series polarizers of the translucent panel assembly to produce a lighted area of the display surface when viewed from the front of the panel.
  • a voltage typically controlled by a thin film transistor, is applied to an electrode in an array of electrodes deposited on one wall of the cell gap.
  • the liquid crystal molecules adjacent to the electrode are attracted by the field created by the voltage and rotate to align with the field.
  • the column of crystals is "untwisted," and the optical axes of the crystals adjacent the cell wall are rotated out of alignment with the optical axis of the corresponding polarizer progressively reducing the local transmittance of the light valve and the intensity of the corresponding display pixel.
  • Color LCD displays are created by varying the intensity of transmitted light for each of a plurality of primary color elements (typically, red, green, and blue) that make up a display pixel.
  • a method of illuminating a display comprising the steps of:
  • said modifying is further based upon modification of a generally first light source of said multi-colored light sources together with modification of the transmittance of said light valve corresponding to at least one of said filters of a different color than said first said multi-colored light sources in such a manner that generally blue light from said generally first light source is converted to a generally second light from said display in a manner that increases the color gamut of said display, wherein said at least one of said filters of said different color and said first light source includes a structure to reduce the leakage of said first light from said first light source through said display.
  • FIG. 1 illustrates a display with a backlight.
  • FIG. 2 illustrates the spectra of a display with RGB LED and RGB LCD.
  • FIG. 3 illustrates a chromaticity diagram of a display with RGB primary.
  • FIG. 4 illustrates a chromaticity diagram of a display with RGBC primary.
  • FIG. 5 illustrates a color difference histogram.
  • FIG. 6 illustrates rendering RGBC to RGB LED and RGB LCD .
  • FIG. 7 illustrates the spectra of a dual LED backlight with blue and yellow.
  • FIG. 8 illustrates a yellow LED from a normally white LED.
  • FIG. 9 illustrates spectra of a display with dual LED and RGB LCD.
  • FIG. 10 illustrates a color gamut of a RGBYC primary display.
  • FIG. 10 illustrates a color gamut of a RGBYC primary display.
  • FIG. 11 illustrates transmittance of a dichroic filter and its angular dependence.
  • FIG. 12 illustrates a convex shaped dichroic filter. Blue light passes phosphor and was reflected back to phosphor at the normal incidence angle.
  • FIG. 13 illustrates a tri-color display structure with phosphor conversions.
  • FIG. 14 illustrates a tri-color display structure with phosphor conversions.
  • FIG. 15 illustrates a color gamut of the display.
  • FIG. 16 illustrates a technique of deriving LED and LCD driving values for a display.
  • a backlit display 20 comprises, generally, a backlight 22, a diffuser 24, and a light valve 26 (indicated by a bracket) that controls the transmittance of light from the backlight 22 to a user viewing an image displayed at the front surface of the panel 28.
  • the light valve typically comprising a liquid crystal apparatus, is arranged to electronically control the transmittance of light for a picture element or pixel. Since liquid crystals do not emit light, an external source of light is necessary to create a visible image.
  • the backlight 22 comprises flourescent light tubes or an array of light sources 30 (e.g., light-emitting diodes (LEDs)), as illustrated in FIG.
  • edge based illumination sources is necessary to produce pixels of sufficient intensity for highly visible images or to illuminate the display in poor lighting conditions.
  • Light radiating from the light sources 30 of the backlight 22 comprises electromagnetic waves vibrating in random planes. Only those light waves vibrating in the plane of a polarizer's optical axis can pass through the polarizer.
  • the light valve 26 includes a first polarizer 32 and a second polarizer 34 having optical axes arrayed at an angle so that normally light cannot pass through the series of polarizers. Images are displayable with an LCD because local regions of a liquid crystal layer 36 interposed between the first 32 and second 34 polarizer can be electrically controlled to alter the alignment of the plane of vibration of light relative of the optical axis of a polarizer and, thereby, modulate the transmittance of local regions of the panel corresponding to individual pixels 38 in an array of display pixels.
  • the layer of liquid crystal molecules 36 occupies a cell gap having walls formed by surfaces of the first 32 and second 34 polarizers.
  • the walls of the cell gap are rubbed to create microscopic grooves aligned with the optical axis of the corresponding polarizer.
  • the grooves cause the layer of liquid crystal molecules adjacent to the walls of the cell gap to align with the optical axis of the associated polarizer.
  • each succeeding molecule in the column of molecules spanning the cell gap will attempt to align with its neighbors.
  • the result is a layer of liquid crystals comprising innumerable twisted columns of liquid crystal molecules that bridge the cell gap.
  • a voltage is applied to a spatially corresponding electrode of a rectangular array of transparent electrodes deposited on a wall of the cell gap.
  • the resulting electric field causes molecules of the liquid crystal adjacent to the electrode to rotate toward alignment with the field.
  • the effect is to "untwist" the column of molecules so that the plane of vibration of the light is progressively rotated away from the optical axis of the polarizer as the field strength increases and the local transmittance of the light valve 26 is reduced.
  • the pixel 38 progressively darkens until the maximum extinction of light 40 from the light source element 42 is obtained.
  • Color LCD displays are created by varying the intensity of transmitted light for each of a plurality of primary color elements (typically, red, green, and blue) elements making up a display pixel.
  • FIG. 1 illustrates a display with a light emitting diode layer used as a backlight for the liquid crystal material. The light from the array of LEDs passes through the diffusion layer and illuminates the LCD.
  • the backlight image is further modulated by the liquid crystal layer.
  • the displayed image is the product of LED backlight and transmittance of LCD, referred to as T LCD (x,y).
  • the dynamic range of display is the product of the dynamic range of LED and LCD.
  • a normalized LCD and LED output may be used to between 0 and 1.
  • red blue green (or other tri-color spectrum of a suitable type of light sources) LED further improves display in terms of the potential color gamut and possible power savings. For an example, if only the red color is displayed, both the green and blue LEDs can be off, which reduces both the power consumption and the leakage from green and blue light sources which lead to a pure color even at lower intensity. The same occurs for the other light sources.
  • the display image may be represented as a function of wavelength (lambda) and characterized as:
  • the products of the RGB LED backlight and RGB LCD form nine distinct spectra, three primary spectra and six secondary spectra as shown in FIG. 2.
  • the secondary spectra is the result of a backlight color (e.g., green backlight) passing through a color filter other than the color filter corresponding to the particular backlight color (e.g., not the green filter).
  • a backlight color e.g., green backlight
  • the spectra of one backlight light source is filtered by a filter for a different backlight light source, to provide a secondary spectra.
  • the green LED to blue LCD is considerably larger than the other secondary spectra, with the other secondary spectra being relatively small in comparison. To reduce the computational requirements the other secondary spectra may be ignored.
  • the technique may incorporate one or more additional secondary spectra, as desired.
  • the resulting four primary spectra, including the crosstalk from the combination of the green LED together with the blue LCD filter, can be modeled as:
  • both the LED values and LCD values can be independently modulated. Since the LED is at a much lower resolution, the LED values in Equation 4 are given by the convolution of the LED driving signal and the point spread function (PSF) of the LED. By utilizing the fourth crosstalk primary, the system may achieve a larger color gamut which as a result displays more real colors in the world, especially in the dark cyan area, as shown in FIG. 3.
  • PSF point spread function
  • the colorimetric model of the system may include a forward model that accepts RGBC input coordinates and predicts the output color tri-stimulus values XYZ (i.e., CIE color coordinates) produced by the system using a 3*4 matrix with dark correction.
  • XYZ i.e., CIE color coordinates
  • X, Y and Z are dark corrected tri-stimulus values and the subscripts R, G, B and C represent for full red, full green, full blue, and the selected crosstalk.
  • the colorimetric model may include an inverse model that uses a single-pass technique to construct the inverse model, which turns an undetermined 3*4 inverse problem to several determined 3*3 transformations.
  • the system may first determine whether the input falls inside RG'B (G' is combined primary of G and C, as is shown in FIG. 4 and calculated in Equation (6)) gamut or not, shown in Equation (7). If RGB 1 scalars are in the range of [0, 1], it means that the input is inside RG'B, and then RGB and C values may be directly calculated.
  • the system may determine whether the input is inside RGB color gamut or not. Similarly, if RGB 2 are within the range of [0, 1], then the input are inside the RGB color gamut (i.e., no crosstalk is necessary, if desired) and the RGBC may be calculated directly as illustrated in Equation (10).
  • the system may use a single pass method to estimate suitable RGBC values. Initially, the system may calculate tri-stimulus value differences introduced by C, as shown in Equation 11 and Equation 12 (dXYZ may be considered a residual). Then GBC may be calculated by inverse matrix of GBC and then it is added back to RGB to determine RGBC values, as shown in Equation 13 and Equation 14. Also, if any of the values are out of range (e.g., greater than 1 or less than zero), they may be clipped back to 1 or 0 so they are at a boundary.
  • dXYZ may be considered a residual
  • GBC may be calculated by inverse matrix of GBC and then it is added back to RGB to determine RGBC values, as shown in Equation 13 and Equation 14. Also, if any of the values are out of range (e.g., greater than 1 or less than zero), they may be clipped back to 1 or 0 so they are at a boundary.
  • the system has the ability to differentiate between multiple different characteristics of the input values to provide better selection of appropriate color values and crosstalk values, if any.
  • the RGBC scalar may be sampled at 0.25 intervals (altogether 625 groups of data) to be used as input RGBC. Its corresponding XYZ and Lab values are calculated accordingly. Then the inverse model is applied to transform XYZ to RGBC. After this, the X'Y'Z' and L'a'b' may be calculated and a color difference metric may be used to evaluate the difference between the input and the output predicted by the inverse model. The result is plotted in Figure 5 and listed in Table 1.
  • the system does not have independent control of C.
  • the system has four degrees of freedoms, which are G LED , G LCD , B LED and B LCD .
  • a suitable rendering technique is illustrates in FIG. 6.
  • a set of device independent set of values (i.e., X, Y, Z) 600 representative of an image to be displayed are converted to a RGBC image 610.
  • the conversion to the image 610 is performed by using Equation 14.
  • the backlight values are selected so that suitable crosstalk will be provided, as desired.
  • the image 610 is sub-sampled 620 to the LED resolution, which is typically lower in resolution.
  • the result of the sub-sampling is an image representative of the spatial distribution of the backlight 630.
  • the first set of special cases is when C is inside the region defined by CGB 640.
  • the second set of special cases 660 is when C is outside the region defined by CGB, but within the RGB gamut.
  • the green and blue LEDs, i.e., G LED and B LED, are adjusted 670 accordingly.
  • the yellow spectrum may be provided from a blue light emitting diode by using a conversion of a generally blue spectrum to a generally yellow spectrum using a Stokes shift, or other suitable mechanism. Referring to FIG. 7, an exemplary such conversion from generally blue to generally yellow is illustrated. As it may be observed, the resulting color spectrum includes a substantially greater amount of yellow. In this case, the resulting display will typically have multiple primary colors plus a yellow primary, such as red, blue, green, yellow.
  • a technique to achieve additional yellow spectrum for the display includes using a selective filter, such as a blue/yellow dichroic filter.
  • a selective filter such as a blue/yellow dichroic filter.
  • Light emitting from a light source partially undergoes a conversion to a generally yellow spectrum.
  • the generally yellow spectrum light passes through the blue yellow dichroic filter.
  • the blue light from the light emitting diode is reflected by the blue yellow dichroic filter.
  • At least part of the reflected blue light from the dichroic filter is again converted by the phosphor to a generally yellow spectrum.
  • the reflected converted light from the blue to yellow phosphor passes through the blue yellow dichroic filter. This reflection and conversion process may continue. In this manner, the luminous output of the yellow may be increased.
  • the backlight is now consist of two colors, blue light from blue LED and the yellow light from blue LED via blue to yellow phosphor.
  • the display image as a function of wavelength (lambda), with yellow included in the display image, may be given by
  • the products of a dual LED backlight and RGBY LCD form eight distinct spectra, four primary spectra and four secondary spectra. Additional backlight spectrum may be used, as desired. Additional LCD filters may be used, as desired. Of the four secondary spectra, the blue LED to yellow and green LCD sub-pixels are quite significant at the cyan spectrum. A crosstalk based color, using the yellow spectrum, may be used as an additional primary in the display, such as a fifth primary in a RGBYC display.
  • the five primaries can be modeled as:
  • LED and LCD values may be independently modulated. Since the LED is at much lower resolution, the LED values in the above equation may be given by the convolution of LED driving signal and the point spread function (PSF) of LED.
  • PSF point spread function
  • the system may achieve a larger color gamut which facilitates the display of more real colors in the world, especially in the dark cyan region.
  • the colorimetric model of the system may include RGBYC input coordinates and predict the output color tristimulus values XYZ produced by the display system using a 3*5 matrix illustrated below.
  • X s , Y s and Z s are tristimulus values and the subscripts r, g, b, y and c represent the red, green, blue, yellow, and crosstalk cyan. It is noted that the C primary may be a crosstalk primary with a much lower spatial resolution than the other primaries.
  • the color may clipped the color to RGBY gamut, and render the residue XYZ in GBC triangle.
  • the dichroic filter shown in FIG. 8 tends to exhibit angular dependence in its cut-off wavelength, as illustrated in FIG. 11. As illustrated, the cut-off wavelength tends to shift from generally 525nm at 0 degrees incidence angle to generally 450nm at 60 degrees incidence angle. Accordingly, the blue light from the light emitting diode leaks through the dichroic filter at large incidence angles, thus reducing the yellow phosphor light, and changing the purity of the resulting color from the display. To improve the efficiency of the dichroic filter and also reduce the blue leakage light, the angular incidence of the blue light on the dichroic filter should be reduced or otherwise controlled.
  • one technique to control the angular incidence of the blue light on the dichroic filter may be achieved by using a convex shaped dichroic filter.
  • the convex shaped dichroic filter reflects all the unconverted blue light back to the phosphor layer which improves the phosphor conversion process.
  • Other shaped dichroic filters and/or light guides may likewise be used to control the angular incidence of the blue light on the dichroic filter.
  • the broad band yellow phosphor may be used to generate a yellow backlight for red and green for a red, green, blue based display (e.g., a multi-colored display).
  • the blue light may be passed either directly, or indirectly, as the blue portion of the backlight for the display.
  • a red color filter may be used to provide an improved red color
  • a green color filter may be used to provide an improved green color
  • a blue color filter may be used to provide an improved blue color, to reduce the effects of unintentionally mixing colors.
  • a diffusion layer may be included, if desired. Other colors and arrangements may likewise be used.
  • a broad band red phosphor and a broad band green phosphor may be used to generate a respective backlight for red and green for a red, green, blue based display (e.g., a multi-colored display).
  • the blue light may be passed either directly, or indirectly, as the blue portion of the backlight for the display.
  • a red color filter may be used to provide an improved red color
  • a green color filter may be used to provide an improved green color
  • a blue color filter may be used to provide an improved blue color, to reduce the effects of unintentionally mixing colors.
  • a diffusion layer may be included, if desired.
  • Narrow spectra band phosphors may be used, such as nano phosphors, if desired. Other colors and arrangements may likewise be used.
  • the display image as a function of wavelength (lambda) may be given by
  • the products of the dual LED backlight and RGBY LCD form six distinct spectra: three primary spectra and three secondary spectra.
  • the secondary spectra can be substantially reduced, and thus effectively ignored.
  • FIG. 15 illustrates the resulting color gamut of the display.
  • the blue and yellow dual color backlight all three primary shifts toward spectral locus, which results in large color gamut. For example, when a blue light is displayed, the yellow backlight can be off, thus reducing LCD leakage due to the limited contrast ratio and also reduces the power consumption.
  • the three primaries maybe modeled as
  • LED and LCD value may be independently modulated. Since the LED is at lower resolution, the LED values in the above equation may be given by the convolution of LED driving signal and the point spread function (PSF) of LED.
  • PSF point spread function
  • FIG. 16 illustrates a technique to convert an input image 800 into a low resolution LED backlight image 810 and a high resolution LCD image 820.
  • the LCD resolution is m x n pixels with its range from 0 to 1, with 0 being black and 1 being the maximum transmittance.
  • the LED resolution is M x N with M ⁇ m and N ⁇ n.
  • the system may assume that the input image has the same resolution as LCD. If input image is of different resolution, a scaling or cropping step may be used to convert the input image to the LCD image resolution.
  • the input image 800 may be low pass filtered 830 by the point spread function of the diffusion screen and sub-sampled 832 (down sample) to an intermediate resolution (M1xN1).
  • M1xN1 may be twice the LED resolution (2Mx2N).
  • the extra resolution of the LCD relative to the LED assists in reducing flickering for moving objects.
  • the input image 800 may be low pass filtered 834 by a smaller filter kernel, such as 5x5 to simulate the size of specular pattern.
  • the low pass filtered 834 image is then divided into M1xN1 blocks, each block corresponding to one LED with some overlap between each block.
  • the block size is (1+k)*(m/M x n/N), where k is the overlapping factor.
  • the block maximum is used to form a LEDmax image (MxN) 836.
  • k is 0.25.
  • the min operation constrains the LED value from 0 to 1.
  • a 1D or 2D lookup table (LUT) may be used to determine the LED driving value from the LEDlp and LEDmax, which provides more flexibility in a tradeoff between power savings and specular highlight preservation. Since the red and green may share the same yellow LEDs, the yellow LED signal is preferably selected to be the max of red and green LED signal 840.
  • a flickering reduction and/or temporal lowpass filtering process 842 may be used.
  • the filtered image 842 may be LED inverse gamma corrected 844, and provided to the LED driver circuit 810.
  • the LED inverse gamma correction 844 may be provided to a LED gamma correction 850.
  • the sub-sampled gamma corrected data may be upsampled 852, preferably to the LCD resolution.
  • the LED1 838 is of size M1 x N1 and range from 0 to 1. Since the PSF of the diffusion screen is typically larger than the LED spacing to provide a more uniform backlight image, there tends to be considerable crosstalk between the LED elements that are located close together.
  • the backlight bl y (x,y) and bl b (x,y) 856 can be predicted by convolves the LED driving signal with the PSF 854.
  • the LCD driving value 858 may be derived by dividing the input image by the respective backlights 856.
  • the LCD driving values 858 may be inverse gamma corrected 860 and provided to the LCD driver circuit 820.
  • a device for illuminating a display carrying out the steps of: (a) spatially varying the luminance of a multi-colored light source illuminating a plurality of pixels of said display in response to receiving a plurality of pixel values; (b) varying the transmittance of a light valve of said display having filters corresponding to said multi-colored light source in response to receiving said plurality of pixel values; and (c) modifying the illumination from said display for said plurality of pixel values based upon modification of said luminance of said light source and said varying said transmittance of said light valve, wherein said modifying is further based upon modification of a generally first light source of said multi-colored light sources together with modification of the transmittance of said light valve corresponding to at least one of said filters of a different color than said first said multi-colored light sources in such a manner that generally blue light from said generally first light source is converted to a generally second light from said display in a manner that increases the

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Abstract

L'invention concerne un procédé d'éclairage d'un dispositif d'affichage, lequel procédé consiste à faire varier spatialement la luminance d'une source de lumière multicolore éclairant une pluralité de pixels du dispositif d'affichage en réponse à la réception d'une pluralité de valeurs de pixel, et à faire varier le facteur de transmission d'un modulateur de lumière du dispositif d'affichage ayant des filtres correspondant à la source de lumière multicolore en réponse à la réception de la pluralité de valeurs de pixel. L'éclairage est modifié pour une pluralité de valeurs de pixel sur la base de la modification de la luminance de la source de lumière et faisant varier le facteur de transmission du modulateur de lumière.
PCT/JP2013/004427 2012-09-05 2013-07-19 Procédé d'éclairage d'un dispositif d'affichage WO2014038122A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006202962A (ja) * 2005-01-20 2006-08-03 Toyoda Gosei Co Ltd 発光装置
US20090174638A1 (en) * 2006-06-02 2009-07-09 Samsung Electronics Co., Ltd. High Dynamic Contrast Display System Having Multiple Segmented Backlight

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006202962A (ja) * 2005-01-20 2006-08-03 Toyoda Gosei Co Ltd 発光装置
US20090174638A1 (en) * 2006-06-02 2009-07-09 Samsung Electronics Co., Ltd. High Dynamic Contrast Display System Having Multiple Segmented Backlight

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