Classifications

• • 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
• • 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
  • G09G3/36—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 using liquid crystals
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
• • 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
• • 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
• • 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
  • G09G2320/06—Adjustment of display parameters
  • G09G2320/0626—Adjustment of display parameters for control of overall brightness
  • G09G2320/0633—Adjustment of display parameters for control of overall brightness by amplitude modulation of the brightness of the illumination source
• • 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
  • G09G2320/06—Adjustment of display parameters
  • G09G2320/0626—Adjustment of display parameters for control of overall brightness
  • G09G2320/0646—Modulation of illumination source brightness and image signal correlated to each other
• • 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
  • G09G2320/06—Adjustment of display parameters
  • G09G2320/066—Adjustment of display parameters for control of contrast
• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
  • G09G2360/00—Aspects of the architecture of display systems
  • G09G2360/16—Calculation or use of calculated indices related to luminance levels in display data
• • 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
• • 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

• Display device with a plurality of pixels and method for displaying images
• the invention relates to a display device with a plurality of pixels, comprising a
• An image signal generating device for generating color and brightness values for the plurality of pixels, a light modulation device coupled to the image signal generation device for modulating the plurality of pixels based on the color and brightness values, and a lighting device for backlighting the light modulation device.
• Display devices in particular flat screens, of the type mentioned above are widely known. They are particularly suitable for use as a computer monitor or as a screen for extra-flat TV sets.
• Light emitted from a light source is used to backlight a modulation device having a plurality of pixels, typically a liquid crystal display (LCD).
• LCD liquid crystal display
• Contrast range desirable. Because movies often contain scenes with a large contrast range, where contrast is the ratio between the difference between maximum and minimum brightness and a minimum displayable brightness gradation.
• a disadvantage of using two light modulation devices is in particular in the high cost of light modulation devices that significantly affect the cost of a video.
• the second modulation device and an image signal generating device required therefor require additional power.
• the series connection of two light modulation devices absorbs a larger proportion of the incident light, so that a particularly powerful light source must be used, which in turn requires more energy.
• Object of the present invention is to describe a display device of the type mentioned, which has a particularly high contrast range.
• the display device should be inexpensive to manufacture and economical in energy consumption.
• a display device of the type mentioned at the beginning in which the lighting device has a drive device for driving a multiplicity of light sources and the drive device is coupled to the image signal generation device or the light modulation device, so that a predetermined group of light sources, which are used to backlight a partial region of the light source Light modulation device is arranged, can be controlled by the driving device in dependence of the brightness values for contrast enhancement.
• the illumination of particularly dark image areas can be reduced, so that the contrast range of the illustrated Overall picture increases.
• the darkening of groups of light sources additionally provides energy savings through more efficient use of light.
• a high contrast can advantageously be achieved with only one light modulator by partially dimming the illumination device, ie the predetermined group of light sources. Due to the dimming darker display areas can be darkened more, which has a greater contrast result.
• each light source of the plurality of light sources can be controlled individually by the drive device. In this way, even small image areas can be darkened individually.
• a display device advantageously operates according to a method of displaying images on a display device having a plurality of pixels, comprising the steps of:
• Light modulation device based on the color and brightness values
• corrected color and brightness values for modulating the predetermined groups of pixels are calculated on the basis of the received color and brightness values of the image signal, taking into account the calculated brightness characteristics.
• the weaker backlighting of predetermined groups of pixels can be taken into account in the modulation, so that, for example, details in darkened image areas can be represented particularly well.
• FIG. 1 shows a schematic structure of a screen according to an embodiment of the invention
• FIG. 2 shows a flow chart for a method for displaying images, 3A to be displayed, exemplary brightness values,
• FIG. 3B shows actual brightness values displayed according to the prior art
• FIG. 3C shows brightness characteristics for the exemplary brightness values
• Figure 3E actually displayed brightness values according to an embodiment of the invention.
• Figure 1 shows in schematic form a structure of a display device 1, in the embodiment of a flat panel, according to an embodiment of the invention in cross section.
• the screen 1 has an image signal generating device 2, a light modulation device 3 and a lighting device 4. Between the
• Lighting device 4 and the light modulation device 3, a diffuser 5 is optionally arranged, which distributes the light of the lighting device 4 for the backlighting of the light modulation device 3.
• a ground glass 6 is additionally arranged, which scatters the translucent light through the light modulation device 3 and at the same time protects the light modulation device 3 from contact.
• the ground glass 6 or the diffuser 5 can also serve to select light of a predetermined polarization direction.
• the image signal generating device 2 has an image signal decoder 7, an image memory 8, a processing unit 9 and a selection means 10.
• the lighting device 4 has a drive device 11 and a plurality of light sources 12, in the exemplary embodiment, light-emitting diodes.
• the light modulation device 3 comprises a plurality of pixels 13 suitable for modulating the incident light.
• the individual pixels 13 are composed of subpixels 14, for example one subpixel 14 each for the three primary colors red, green and blue, which allow only the light of the respective primary color to pass through corresponding filters.
• the drive device 11 of the lighting device 4 is set up to control each of the light sources 12 individually, so that the individual light sources 12 spatially assigned groups of pixels 15A, 15B and 15C can be backlit differently.
• the modulator 5 has three mutually delimited areas, so that light of a light source 12 backlit only one group of pixels 15A, 15B or 15C. Alternatively, illumination of adjacent groups 15A, 15B or 15C may also be considered by the processing unit 9.
• display devices 1 naturally have substantially more pixels 13 and light sources 12 used for their illumination than can be shown in FIG.
• an illumination device 4 with approximately 200 light-emitting diodes can be used as the light sources 12 are arranged, for example, strip or kacheiförmig.
• Figure 2 illustrates a method for displaying images on a display device 1 according to an embodiment of the invention.
• an image signal for example a television signal
• the image signal decoder 7 which contains the color and brightness values I so ii contained therein for the pixels 13.
• the decoded image and brightness values I so ii are stored in the image memory 8 for further processing.
• luminance characteristics I Char for predetermined groups of pixels 15 are calculated on the basis of the color and brightness values I so ii stored in the image memory 8.
• the screen 1 has three groups 15A, 15B and 15C of picture elements.
• the upper, middle and lower groups 15A, 15B and 15C are each assigned to one of the light sources 12 and illuminated by them.
• the processing unit 9 in the second step 22 it is recognized by the processing unit 9 in the second step 22 that the lower screen area corresponding to the lower group of pixels 15C represents a particularly dark image area.
• This information is then stored in the brightness characteristic I C har generated for the group 15C.
• the plurality of pixels 13 are modulated by the light modulation device 3 in consideration of the decoded color and brightness values Isoii. For example, by applying different voltages to the individual pixels 13 of the light modulation device 3, the permeability of the pixels 13 or of the subpixels 14 for individual colors can be influenced in such a way that an overall image is created for a viewer.
• crystals of a liquid crystal display are deflected by generating an electric field such that their polarization direction changes so that the light of a predetermined polarization is either transmitted or absorbed.
• the processing unit 9 takes into account the previously calculated brightness characteristic I Char in the actual actual modulation of the pixels 13.
• the color and brightness values corrected from the received color and brightness values I so are ii taking into account the calculated brightness characteristic I C har Ikorr used to modulate the pixels 13 of the light modulation device 3.
• a fourth step 24 the lighting device 4 with the associated drive device 11 is controlled by the processing device 9 such that the illumination of the individual groups of pixels 15A, 15B and 15C corresponds to the previously determined brightness characteristics I C har.
• the group of pixels 15C are darkened by darkening the associated lower light source 12.
• the described process is repeated after a predetermined time, so that both the pixels 13 of the light modulation device 3 and the light sources 12 of the lighting device 4 are continuously driven according to the needs of each current image signal.
• FIG. 3A shows brightness values I so II for each of the pixels 13 to be represented by the screen 1.
• brightness values I so are considered alone, but no color information.
• the calculation described below is performed for each of the illustrated colors, such as red, green and blue.
• the three first pixels 13 of the first group of pixels 15A are intended to represent a very bright image area.
• the next three pixels 13 of the second group of pixels 15B represent a medium-bright image area.
• the last three pixels 13 of the last group 15C represent a very dark image area.
• a brightness value I is such for each of the pixels to be displayed 13 in percent.
• FIG. 3B shows the actually displayed brightness intensity I S d ⁇ of a screen 1 according to FIG State of the art with an exemplary contrast ratio of 1:10.
• a light modulation device 3 can only represent ten different brightness levels.
• the brightness values shown in FIG. 3A can only be displayed correctly in the regions of the first and second group of pixels 15A and 15B.
• the very low brightness in the area of the third group of pixels 15C no longer allows a signal and thus realistic representation.
• this image area is completely darkened, so that details contained therein are no longer displayed.
• FIG. 3C shows luminance characteristics I Char determined according to an embodiment of the invention.
• the respective maximum value of a group of pixels 15A, 15B or 15C is used as the brightness characteristic.
• the first light source 12 of the first group 15A is driven at 100 percent of the possible power, the second light source 12 at 60 percent of the possible power, and the third light source 12 at only one percent of the possible power. Since the luminous intensity of light-emitting diodes used as light source 12 in the exemplary embodiment increases substantially linearly with an operating current, the individual light sources 12 can be controlled as required, for example, by current control.
• FIG. 3D shows corrected brightness values Ikorr for driving the modulation device 3, which are calculated by the processing unit 9, for example.
• the Embodiment yield the corrected brightness values Ikorr by dividing the displayed brightness values I so ii of Figure 3A by the calculated brightness characteristic I C har of Figure 3B.
• FIG. 3E the brightness values I lst perceived by a viewer on the screen 6 are shown. Since the brightness values I visible on the ground glass 6 essentially result from multiplication of the illumination intensity corresponding to the brightness characteristic I C har shown in FIG. 3C with the corrected brightness values I kOrr of FIG. 3D used for the modulation, the brightness values I illustrated in FIG For each of the individual pixels 13, the brightness values I contained in the image signal are exactly the same . Thus, a true-to-life rendition of the image signal is possible.
• individual image areas can also be specifically darkened or lightened with the aid of the selection means 10.
• a screen 1 is used to display the image signal
• the method of the invention can of course be used in other display methods and devices, for example, in a projection or rear projection, such as a video projector or so-called beamer.
• a reflective one instead of a filtering light modulation device 3 such as a liquid crystal display
• Modulation device 9 such as a matrix of controllable mirrors (Digital Mirror Device - DMD) to use.
• light-emitting diodes instead of the light-emitting diodes used in the exemplary embodiment, it is also possible to use other light sources 12, in particular small-area light sources, which are suitable for illuminating individual groups of pixels 15. It is advantageous if the light sources
• OLEDs organic, surface-emitting light-emitting diodes

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Theoretical Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Nonlinear Science (AREA)
• Mathematical Physics (AREA)
• Optics & Photonics (AREA)
• Control Of Indicators Other Than Cathode Ray Tubes (AREA)
• Liquid Crystal Display Device Control (AREA)

Applications Claiming Priority (2)

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• 2005
  • 2005-12-14 DE DE102005059765A patent/DE102005059765A1/de not_active Withdrawn
• 2006
  • 2006-11-30 JP JP2008544939A patent/JP2009519478A/ja not_active Withdrawn
  • 2006-11-30 CA CA002633864A patent/CA2633864A1/en not_active Abandoned
  • 2006-11-30 KR KR1020087016942A patent/KR20080081968A/ko not_active Application Discontinuation
  • 2006-11-30 CN CNA2006800467192A patent/CN101326565A/zh active Pending
  • 2006-11-30 EP EP06830206A patent/EP1960987A1/de not_active Withdrawn
  • 2006-11-30 WO PCT/EP2006/069102 patent/WO2007068594A1/de active Application Filing
  • 2006-11-30 US US12/086,473 patent/US20090109248A1/en not_active Abandoned
  • 2006-12-08 TW TW095146003A patent/TW200746004A/zh unknown

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