Source: https://patents.google.com/patent/CN101785044B/en
Timestamp: 2020-05-25 22:23:11
Document Index: 799408588

Matched Legal Cases: ['arts\n21', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15', 'art 15']

CN101785044B - Image display device - Google Patents
CN101785044B
CN101785044B CN 200880104066 CN200880104066A CN101785044B CN 101785044 B CN101785044 B CN 101785044B CN 200880104066 CN200880104066 CN 200880104066 CN 200880104066 A CN200880104066 A CN 200880104066A CN 101785044 B CN101785044 B CN 101785044B
CN 200880104066
CN101785044A (en
2007-10-25 Priority to JP2007-277708 priority Critical
2007-10-25 Priority to JP2007277708 priority
2008-09-26 Application filed by 夏普株式会社 filed Critical 夏普株式会社
2008-09-26 Priority to PCT/JP2008/067382 priority patent/WO2009054223A1/en
2010-07-21 Publication of CN101785044A publication Critical patent/CN101785044A/en
2012-08-15 Publication of CN101785044B publication Critical patent/CN101785044B/en
An area active drive processing unit (15) obtains liquid crystal data (32) used for driving a liquid crystal panel (11) and LED data (33) used for driving backlight (13) from an input image (31). In order to obtain the LED data (33), the input image (31) is divided into areas, a maximum value Ma and a mean value Me of luminances of pixels in each area are obtained, and a weighted mean of the maximum value Ma and the mean value Me is obtained, thereby obtaining the luminance of an LED (23)-(25) corresponding to each area. A coefficient a used for obtaining the weighted mean changes depending on the mean value Me. As the mean value Me increases, the LED luminance increases from the mean value Me at an accelerated rate and approaches the maximum value Ma. As a result, flicker and lowering of luminance in an image display device controlling backlight are prevented.
The present invention relates to image display device, particularly have the image display device of the function (backlight light-adjusting function) of the brightness of controlling backlight.
Comprise in the image display device of backlight at liquid crystal indicator etc.,, can suppress the power consumption of backlight, improve the image quality of display image through control the brightness of backlight based on input picture.Particularly through picture segmentation being become a plurality of zones,,, can further realize low power consumption and high image qualityization to controlling with the brightness of the light source of this corresponding backlight in zone based on the input picture in the zone.Below, the brightness of such light source of controlling backlight based on the input picture in the zone as stated and the method that drives display panel are called " area active drive ".
Light emitting diode) or White LED in the image display device that carries out area active drive,, for example use LED (the Light Emitting Diode: of RGB three looks as the light source of backlight.As the method for brightness of these LED of decision, known in the past have two kinds of following methods.The maximal value of brightness that first method is based on the pixel in the zone decides the method (hereinafter, being called the Max mode) with the brightness of this zone corresponding LED.The mean value of brightness that second method is based on the pixel in the zone decides the method (hereinafter, being called the Mean mode) with the brightness of this zone corresponding LED.
Usually, the number of the LED that is comprised in the backlight is less than the pixel count of display panel.Therefore, if utilize area active drive to show dynamic image, then the maximal value (or mean value) of the brightness of the pixel in the zone changes by frame, and the brightness of LED changes by frame, in picture, produces scintillation (flicker) sometimes.This scintillation is more obvious when conversation structure is brighter when picture is dark.In the image display device that carries out area active drive, prevent that the scintillation in the dynamic image demonstration from becoming important problem.
In addition, about the present invention, known have a following prior art document.In patent documentation 1, putting down in writing cold cathode fluorescent tube and light emitting diode are carried out that disposed adjacent constitutes backlight and make up the technology that drives cold cathode fluorescent tube and light emitting diode according to picture brightness.In patent documentation 2, the lightness of putting down in writing the illumination light of calculating the lighting unit that is made up of a plurality of light sources distributes and distributes the technology of correction image data based on the lightness of being calculated.In patent documentation 3, putting down in writing in the image display device that dynamically luminosity of the light source of backlight is changed control, coming shielding the technology that changes control with the intensity level of display image signals that shows according to the luminosity of the light source of backlight.
Patent documentation 1: Japanese Patent Laid is opened the 2003-140110 communique
Patent documentation 2: Japanese Patent Laid is opened the 2005-309338 communique
Patent documentation 3: Japanese Patent Laid is opened the 2005-321423 communique
Yet (Fig. 6 that states after the reference and the explanation of Figure 10) has problems respectively in above-mentioned Max mode and Mean mode.In the Max mode, having can be with the advantage of correct brightness display image, but has following problem: promptly, the scintillation when dynamic image shows is bigger, because scintillation is big thereby can't the enlarged area size.On the other hand, in the Mean mode, have that scintillation is less, the image quality improving effect is higher than the advantage of Max mode, but have following problem: promptly, produce brightness and descend, can't come display image with correct brightness.Usually, it is relatively poor to think that the Max mode shows for dynamic image, and the Mean mode shows relatively poor for still image.
Therefore, the object of the present invention is to provide a kind of image display device, this image display device can prevent scintillation and the brightness decline both of these case in still image shows in dynamic image shows, carries out area active drive.
First aspect of the present invention is the image display device with function of the brightness of controlling backlight, it is characterized in that, comprising:
Display panel, above-mentioned display panel comprises a plurality of display elements;
Backlight, above-mentioned backlight comprises a plurality of light sources;
Signal processing part, above-mentioned signal processing part are obtained demonstration with data and backlight control data based on input picture;
Panel drive circuit, above-mentioned panel drive circuit is used data based on above-mentioned demonstration, comes the signal to the light transmission of the above-mentioned display element of above-mentioned display panel output control; And
Backlight source driving circuit, above-mentioned backlight source driving circuit come the signal to the brightness of the above-mentioned light source of above-mentioned backlight output control based on above-mentioned backlight control data,
Above-mentioned signal processing part is when obtaining above-mentioned backlight control data; Above-mentioned input picture is divided into a plurality of zones; Obtain the maximal value and the mean value of brightness of the pixel in each zone, obtain the brightness with each regional corresponding light source based on the maximal value of obtaining and mean value.
Second aspect of the present invention is characterised in that, in first aspect of the present invention,
Above-mentioned signal processing part is through carrying out the brightness that weighted mean is obtained above-mentioned light source to above-mentioned maximal value and above-mentioned mean value.
The third aspect of the invention is characterised in that, in second aspect of the present invention,
Above-mentioned signal processing part provides the weight that changes according to above-mentioned mean value, and above-mentioned maximal value and above-mentioned mean value are carried out weighted mean.
Fourth aspect of the present invention is characterised in that, in the third aspect of the invention,
Above-mentioned signal processing part provides big more weight to above-mentioned maximal value when above-mentioned mean value is big more, to above-mentioned mean value more little weight is provided, and above-mentioned maximal value and above-mentioned mean value are carried out weighted mean.
The 5th aspect of the present invention is characterised in that, in the third aspect of the invention,
Above-mentioned signal processing part provides the weight of the bigger variation of generation when above-mentioned mean value is big more, above-mentioned maximal value and above-mentioned mean value are carried out weighted mean.
The 6th aspect of the present invention is characterised in that, in second aspect of the present invention,
Above-mentioned signal processing part the variation of brightness with the pixel in the zone be judged to be than hour, provide greater than previous weight to above-mentioned maximal value, provide less than previous weight to above-mentioned mean value, above-mentioned maximal value and above-mentioned mean value are carried out weighted mean.
The 7th aspect of the present invention is characterised in that, in first aspect of the present invention,
When above-mentioned signal processing part is still image at above-mentioned input picture, obtain the brightness of above-mentioned light source based on above-mentioned maximal value.
Eight aspect of the present invention is the method for displaying image in the image display device, and above-mentioned image display device comprises: comprise the display panel and the backlight that comprises a plurality of light sources of a plurality of display elements, it is characterized in that, comprising:
Based on input picture, obtain the step that shows with data and backlight control data;
Based on above-mentioned demonstration with data, come step to the signal of the light transmission of the above-mentioned display element of above-mentioned display panel output control; And,
Based on above-mentioned backlight control data, come step to the signal of the brightness of the above-mentioned light source of above-mentioned backlight output control,
Obtain in the step of above-mentioned demonstration with data and above-mentioned backlight control data; When obtaining above-mentioned backlight control data; Above-mentioned input picture is divided into a plurality of zones; Obtain the maximal value and the mean value of brightness of the pixel in each zone, obtain the brightness with each regional corresponding light source based on the maximal value of obtaining and mean value.
According to of the present invention first or eight aspect; Through the two obtains the brightness of light source based on the maximal value of the brightness of pixel and mean value; Compare and only use peaked mode; Can suppress the scintillation in the dynamic image demonstration, compare the mode of only using mean value, the brightness that can suppress in the still image demonstration descends.Thereby, can prevent the brightness decline both of these case in the scintillation of dynamic image in showing and the still image demonstration.
According to a second aspect of the invention; Maximal value and mean value through to the brightness of pixel carry out weighted mean; Can easily obtain based on the two the brightness of light source of maximal value and mean value, can prevent the brightness decline both of these case in the scintillation of dynamic image in showing and the still image demonstration.
According to a third aspect of the invention we; Through mean value the weight when carrying out weighted mean is changed according to the brightness of pixel; Thereby make maximal value or the mean value of the brightness of light source according to input picture, can prevent the brightness decline both of these case in the scintillation of dynamic image in showing and the still image demonstration near the brightness of pixel.
According to a forth aspect of the invention; Through when the mean value of the brightness of pixel is big, making the maximal value of the brightness of light source near the brightness of pixel; Can prevent the tangible scintillation when input picture is dark, and when preventing that input picture is brighter, the brightness that becomes problem descends.
According to a fifth aspect of the invention, because the mean value of the brightness of pixel when big more, the weight when carrying out weighted mean have greatly changed, therefore if mean value increases, then the brightness of light source is quickened to increase, promptly near the maximal value of the brightness of pixel.Thereby the brightness that can more effectively prevent when input picture is brighter, becomes problem descends.
According to a sixth aspect of the invention, though when brightness does not change or the variable quantity of brightness hour, the brightness of light source also increases gradually, finally reaches the maximal value of the brightness of pixel.Thereby, can prevent fully that the brightness in the rest image demonstration from descending.
According to a seventh aspect of the invention, through when input picture is rest image, obtain the brightness of light source, can prevent fully at once that the brightness of still image in showing from descending based on the maximal value of pixel.
Fig. 1 is an expression embodiment of the present invention 1 and the block diagram of the structure of the related liquid crystal indicator of embodiment 2.
Fig. 2 is the figure of the details of expression backlight shown in Figure 1.
Fig. 3 is the process flow diagram of the processing of the area active drive handling part in the related liquid crystal indicator of expression embodiment of the present invention 1.
Fig. 4 is the figure of example of corresponding relation of mean value and alpha of the brightness of pixel in the related liquid crystal indicator of expression embodiment of the present invention 1, in the zone.
Fig. 5 be illustrated in the related liquid crystal indicator of embodiment of the present invention 1, up to the figure of the process that obtains liquid crystal data and LED data.
Fig. 6 is the figure that is illustrated in the example of the picture that produces scintillation in the existing Max mode.
Fig. 7 is the figure of the variation of the contrast table brightness that is shown in the LED when showing picture shown in Figure 6.
Fig. 8 is the process flow diagram that the coefficient decision in the related liquid crystal indicator of embodiment of the present invention 2 is handled.
Fig. 9 is the figure of example of corresponding relation of mean value and alpha of the brightness of pixel in the related liquid crystal indicator of expression embodiment of the present invention 2, in the zone.
Figure 10 is the figure that is illustrated in the example of the picture that produces brightness decline in the existing Mean mode.
Figure 11 is the figure of the variation of the contrast table brightness that is shown in the LED when showing picture shown in Figure 10.
10 liquid crystal indicators
11 liquid crystal panels
12 panel drive circuits
13 backlights
14 backlight source driving circuits
15 area active drive handling parts
21 display elements
The 22LED unit
23 red LED
24 green LED
25 blue leds
31 input pictures
32 liquid crystal data
The 33LED data
41,51 zones
52 zonules
Fig. 1 is the block diagram of the structure of the related liquid crystal indicator of expression embodiment of the present invention 1.Liquid crystal indicator 10 shown in Figure 1 comprises: liquid crystal panel 11, panel drive circuit 12, backlight 13, backlight source driving circuit 14, and area active drive handling part 15.Liquid crystal indicator 10 is a plurality of zones with picture segmentation, carries out area active drive, and the input picture that the active driving of above-mentioned zone is based in the zone is controlled the brightness of the light source of backlight, and drives liquid crystal panel 11.Below, establishing m and n is the integer more than 2, and establishing p and q is the integer more than 1, and at least one side is the integer more than 2 among p and the q.
Import the input picture 31 that comprises R image, G image, reaches the B image to liquid crystal indicator 10.R image, G image, and the B image all comprise the (m * n) brightness of individual pixel.Area active drive handling part 15 is based on input picture 31; Obtain the demonstration that is used to drive liquid crystal panel 11 with data (below; Be called liquid crystal data 32) and be used to drive the backlight control data (below, be called LED data 33) (details will be narrated below) of backlight 13.
Liquid crystal panel 11 comprises (m * n * 3) individual display element 21.Display element 21 is gone up 3m of configuration at every line direction (being horizontal among Fig. 1), goes up n of configuration at every column direction (being vertical among Fig. 1), is configured to two-dimentional shape as a whole.In the display element 21, include transmission cross G display element that the R display element of red light, transmission cross green light, and transmission cross the B display element of blue light.R display element, G display element, and the B display element follow direction and row arrangement, form a pixel with three.
Panel drive circuit 12 is driving circuits of liquid crystal panel 11.Panel drive circuit 12 comes the signal (voltage signal) to the light transmission of liquid crystal panel 11 output control display elements 21 based on the liquid crystal data 32 from 15 outputs of area active drive handling part.To write the pixel electrode (not shown) in the display element 21 from the voltage of panel drive circuit 12 outputs, the light transmission of display element 21 changes according to the voltage that writes pixel electrode.
Backlight 13 is arranged at the rear side of liquid crystal panel 11, backlight illumination is mapped to the back side of liquid crystal panel 11.Fig. 2 is the figure of the details of expression backlight 13.That kind as shown in Figure 2, backlight 13 comprise (the individual LED of p * q) unit 22.LED unit 22 disposes p on every line direction, q of configuration on every column direction, be configured to two-dimentional shape as a whole.LED unit 22 comprises red LED 23.Green LED 24, and each one of blue led 25.The illumination that three LED23 to 25 that comprised from a LED unit 22 launch is to the part at the back side of liquid crystal panel 11.
Backlight source driving circuit 14 is driving circuits of backlight 13.Backlight source driving circuit 14 comes the signal (voltage signal or current signal) to the brightness of backlight 13 output control LED23 to 25 based on the LED data 33 from 15 outputs of area active drive handling part.With in the brightness of LED23 to 25 and the unit and the brightness of the LED outside the unit independently control.
Be that (the individual zone of p * q), a zone is corresponding with a LED unit 22 with the picture segmentation of liquid crystal indicator 10.Area active drive handling part 15 is respectively to (brightness with the corresponding red LED 23 in this zone is obtained based on the R image in the zone in the individual zone of p * q).Equally, the G image that the brightness of green LED 24 is based in the zone decides, and the brightness of blue led 25 is based on that B image in the zone decides.Area active drive handling part 15 is obtained the brightness of all LED23 to 25 that backlight 13 comprised, and 33 pairs of backlight source driving circuits 14 of LED data of the expression LED brightness of obtaining are exported.
In addition, area active drive handling part 15 is obtained the brightness of the backlight light in all display elements 21 that comprised in the liquid crystal panel 11 based on LED data 33.Have again; Area active drive handling part 15 is based on the brightness of input picture 31 and backlight light; Obtain the light transmission of all display elements 21 that liquid crystal panel 11 comprised, the liquid crystal data 32 counter plate driving circuits 12 of the expression light transmission of being obtained are exported.
In liquid crystal indicator 10, the brightness of R display element is long-pending from the light transmission of the brightness of the red light of backlight 13 ejaculations and R display element.The light that penetrates from a red LED 23 is mapped to a plurality of zones with a zone of correspondence as the center.Thereby the brightness of R display element is long-pending from the light transmission of the summation of the brightness of the light of a plurality of red LED 23 ejaculations and R display element.Equally; The brightness of G display element is long-pending from the light transmission of the summation of the brightness of the light of a plurality of green LED 24 ejaculations and G display element, and the brightness of B display element is long-pending from the light transmission of the summation of the brightness of the light of a plurality of blue leds 25 ejaculations and B display element.
According to the liquid crystal indicator 10 that adopts above structure; Through obtain suitable liquid crystal data 32 and LED data 33 based on input picture 31; Control the light transmission of display element 21 based on liquid crystal data 32; Control the brightness of LED23 to 25 based on LED data 33, thereby can input picture 31 be shown in liquid crystal panel 11.In addition, the pixel intensity in the zone than hour, through reducing the brightness with this zone corresponding LED 23 to 25, can reduce the power consumption of backlight 13.In addition, the pixel intensity in the zone hour through between the level of smaller amounts, switching and the brightness of the corresponding display element 21 in this zone, can improve the resolution of image, improves the image quality of display image.
Fig. 3 is the process flow diagram of the processing of expression area active drive handling part 15.Image to certain color component that area active drive handling part 15 is comprised in input picture 31 (below be called color component C) is imported (step S11).Include (m * n) the brightness of individual pixel in the input picture of color component C.
Then, the input picture of 15 couples of color component C of area active drive handling part carries out auxiliary sampling and handles (equalization processing), obtains and comprise (the downscaled images (step S12) of the pixel intensity of individual (s is the integer more than 2) of sp * sq).In step S12, the input picture of color component C longitudinally is reduced into (sq/n) doubly along laterally being reduced into (sp/m) doubly.Then, area active drive handling part 15 is divided into downscaled images (p * q) individual zone (step S13).Include (the pixel intensity that s * s) is individual in each zone.
Then, (the mean value Me (step S14) of brightness of maximal value Ma and the pixel in the zone of the brightness of the pixel in the zone is obtained in the individual zone of p * q) to area active drive handling part 15 for each.Then, (LED brightness (step S15) is obtained based on maximal value Ma and mean value Me in the individual zone of p * q) to area active drive handling part 15 for each.In step S15,, come maximal value Ma and mean value Me are carried out weighted mean, thereby obtain LED brightness E through using following formula (1).
E＝Me+(Ma-Me)×α
＝α×Ma+(1-α)×Me (1)
The alpha that following formula (1) is comprised is the weight when carrying out weighted mean, and its typical case gets the value below 1 more than 0.Alpha changes according to mean value Me, along with mean value Me increases and increases.In addition, at mean value Me hour, even mean value Me changes; Alpha also not too changes; When mean value Me was big, if mean value Me changes, then alpha had greatly changed; When mean value surpassed predetermined value with respect to the ratio (Me/Ma) of maximal value, alpha became 1.Fig. 4 is the figure of example of the corresponding relation of expression mean value Me and alpha.In Fig. 4, mean value Me gets the value in 0 to 4095 the scope, and alpha is carried out the variation in 16 stages.In addition, the also desirable negative value of alpha.
As stated, area active drive handling part 15 provides the weight that changes according to mean value Me, and maximal value Ma and mean value Me are carried out weighted mean.At this moment, area active drive handling part 15 provides big more weight to maximal value Ma when mean value Me is big more, to mean value Me more little weight is provided.In addition, big more variation takes place in this weight when mean value Me is big more.
Then; Area active drive handling part 15 through to utilize that step 15 obtains (brightness diffusion filter (some diffusion filter) is used in p * q) individual LED brightness, thereby obtains and comprise (the first back light source brightness data (step S16) of the brightness of individual (t is the integer more than 2) of tp * tq).In step S16, (p * q) individual LED brightness is expanded as t doubly to horizontal and vertical respectively.
Then, area active drive handling part 15 is handled through the first back light source brightness data being carried out linear interpolation, obtains and comprise (the second back light source brightness data (step S17) of individual brightness of m * n).In step S17, the first back light source brightness data along horizontal expansion be (m/tp) doubly, longitudinally expand as (n/tq) doubly.The second back light source brightness data representation is in that (brightness that the LED of individual color component C of p * q) obtains with step S15 carries out when luminous, incide (m * n) the brightness of the backlight light of the color component C of the display element 21 of individual color component C.
Then; Area active drive handling part 15 through comprised in the input picture with color component C (brightness of the individual pixel of m * n) respectively divided by comprised in the second back light source brightness data (brightness that m * n) is individual, thus obtain (the light transmission T (step S18) of the display element 21 of individual color component C of m * n).
At last; Area active drive handling part 15 is for color component C output liquid crystal data 32 and LED data 33; (light transmission that m * n) is individual, (the LED brightness (step S19) that p * q) is individual that above-mentioned LED data 33 expressions are obtained by step S15 that 32 expressions of above-mentioned liquid crystal data are obtained by step S18.At this moment, liquid crystal data 32 and LED data 33 are transformed to the value in the suitable scope according to the specification of panel drive circuit 12 and backlight source driving circuit 14.
Area active drive handling part 15 through to R image, G image, and the B image carry out processing shown in Figure 3; Thereby, obtain the liquid crystal data 32 of the individual light transmission of expression (m * n * 3) and the LED data 33 of the individual LED brightness of expression (p * q * 3) based on the input picture 31 of the brightness that comprises (m * n * 3) individual pixel.
Fig. 5 is the figure that is illustrated under the situation of m=1920, n=1080, p=32, q=16, s=10, t=5 up to the process that obtains liquid crystal data and LED data.That kind as shown in Figure 5 is carried out auxiliary sampling through the input picture to the color component C of the brightness that comprises (1920 * 1080) individual pixel and is handled, and is comprised the downscaled images of the brightness of (320 * 160) individual pixel.Downscaled images is divided into (32 * 16) individual zone (area size is (10 * 10) pixel).The maximal value Ma and the mean value Me of the brightness through each zone being obtained pixel are comprised (32 * 16) individual peaked maximum value data and are comprised the average data of (32 * 16) individual mean value.Through maximum value data and average data are applied to following formula (1), obtain the LED data of the color component C of the individual LED brightness of expression (32 * 16).
LED data through with color component C are applied to the brightness diffusion filter; The first back light source brightness data that comprised (160 * 80) individual brightness; Handle through the first back light source brightness data being carried out linear interpolation, comprised the second back light source brightness data of (1920 * 1080) individual brightness.At last, through with the brightness of the pixel that is comprised in the input picture divided by the brightness that is comprised in the second back light source brightness data, comprised the liquid crystal data of the color component C of (1920 * 1080) individual light transmission.
In addition, in Fig. 3, explanation for ease, area active drive handling part 15 is successively the image of each color component to be handled, but also can handle the image of each color component to timesharing.In addition, in Fig. 3, area active drive handling part 15 is in order to remove noise input picture to be carried out auxiliary sampling to handle, and carries out area active drive based on downscaled images, but also can carry out area active drive based on original input picture.
Below, the effect of the related liquid crystal indicator of this embodiment 10 is described.The method of the brightness of the decision LED (light source of backlight) when carrying out area active drive; Known in the past have following two kinds of methods: promptly, decide the method (Max method) of the brightness of LED and decide the method (Mean method) of the brightness of LED based on the mean value of the brightness of the pixel in the zone based on the maximal value of the brightness of the pixel in the zone.In liquid crystal indicator 10, the brightness of LED is based on maximal value Ma and mean value Me, the use following formula (1) of the brightness of the pixel in the zone and calculates.In such liquid crystal indicator 10, the brightness of LED is to use the new method that made up Max mode and Mean mode (below, be called the Mix mode) to decide.
Here, that kind as shown in Figure 6, the situation that the dynamic image of considering in the background of black (brightness is 0%), the bar 42 of the white (brightness is 100%) of 70% width with zone 41 being moved left shows.Among the figure, establish bar 42 and move with the speed that time per unit moves an amount of pixels of downscaled images.In this case, the maximal value Ma of the pixel intensity of zone in 41 gets at regional 41 o'clock in the part of bar 42 and rises to 100% from 0% at once.In addition, the mean value Me of the brightness of the pixel of zone in 41 is interior and rise to 70% from 0% gradually along with bar 42 carries out zone 41.
Fig. 7 be expression when using Max mode, Mean mode and Mix mode to show picture shown in Figure 6, with the figure of the variation of the brightness of regional 41 corresponding LED.When showing this picture with the Max mode, identical with the brightness of regional 41 corresponding LED with maximal value Ma, if the part of bar 42 gets in the zone 41, then rise to 100% (with reference to the dot-and-dash line of Fig. 7) from 0% at once.In such Max mode,, therefore in picture, produce bigger scintillation because the brightness of LED changes sharp.
When showing this picture, with the brightness and the mean value Me identical change of regional 41 corresponding LED, along with little by little rising to 70% (with reference to the thick dashed line of Fig. 7) in the entering regional 41 of bar 42 from 0% with the Mean mode.Therefore, in the Mean mode, flicker not too can become problem.But, because the brightness maximum of LED also can only arrive 70%, therefore produce brightness and descend, can't come show white with correct brightness.
In the related liquid crystal indicator 10 of this embodiment, mean value Me is big more, and the alpha that following formula (1) is comprised is big more, and the variable quantity of alpha is also big more.Therefore, when mean value Me rose with certain speed, alpha was quickened to rise since 0 and is come near 1.According to the LED brightness E of following formula (1), be 0 o'clock in alpha, equate with the brightness of Mean mode, be 1 o'clock at coefficient, equate with the brightness of Max mode.Thereby, in the liquid crystal indicator 10 that uses the Mix mode, with the brightness of regional 41 corresponding LED at first near the brightness of Mean mode, this after-acceleration is risen, near the brightness of Max mode.In example shown in Figure 7, the brightness of LED greater than the brightness of Mean mode, equates with the brightness of Max mode after moment t2 after moment t1.
In such Mix mode, because the brightness of LED increases gradually, therefore same with the Mean mode, scintillation not too can become problem.In addition, after the moment t1 of brightness greater than the brightness of Mean mode of LED, brightness descends less than the Mean mode, becomes in the brightness of LED after 100% the moment t2, does not produce brightness and descends.
Thus; According to the liquid crystal indicator 10 that uses the Mix mode; Through the two obtains the brightness with this zone corresponding LED 23 to 25 based on maximal value Ma and the mean value Me of the brightness of the pixel in the zone; The scintillation during thereby the dynamic image that can suppress to utilize the Max mode shows also can suppress to utilize the brightness in showing of the still image of Mean mode to descend.
In addition, area active drive handling part 15 carries out weighted mean through the maximal value Ma and the mean value Me of brightness to the pixel in the zone, obtains the brightness of LED23 to 25.Thus, the two the brightness of LED23 to 25 can be easily obtained, scintillation and the brightness decline both of these case in still image shows in dynamic image shows can be prevented based on maximal value Ma and mean value Me.
In addition, area active drive handling part 15 changes the alpha (weight when carrying out weighted mean) that is comprised in the following formula (1) according to the mean value Me of the brightness of the pixel in the zone.Thus, make the maximal value Ma or the mean value Me of the brightness of the pixel in the brightness access areas of LED23 to 25 according to input picture 31, can prevent scintillation and the brightness decline both of these case in still image shows in dynamic image shows.
In addition, when the mean value Me of the brightness of the pixel of area active drive handling part 15 in the zone is big, make the maximal value Ma of the brightness of LED23 to 25 near the brightness of pixel.Thus, can prevent scintillation showy when input picture 31 is dark, and prevent that the brightness that when input picture 31 is brighter, becomes problem from descending.
In addition, when the mean value Me of the brightness of the pixel of area active drive handling part 15 in the zone is big more, make the alpha that is comprised in the following formula (1) carry out big more variation.Therefore, if mean value Me increases, then the brightness of LED23 to 25 is just quickened to increase, promptly near the maximal value Ma of the brightness of pixel.Thus, in the time of preventing more effectively that input picture 31 is brighter, the brightness that becomes problem descends.
As stated; The liquid crystal indicator related according to this embodiment; Through the two obtains the brightness with this zone corresponding LED (light source of backlight) based on maximal value and the mean value of the brightness of the pixel in the zone, can prevent scintillation and the brightness decline both of these case in the still image demonstration in dynamic image shows.
The related liquid crystal indicator of embodiment 2 of the present invention has identical structure (with reference to Fig. 1) with embodiment 1 related liquid crystal indicator 10.In the related liquid crystal indicator of embodiment 1, in step S15 shown in Figure 3, alpha is based on that the mean value Me of the brightness of the pixel in the zone decides.Yet alpha is less than 1 sometimes, and during showing still image, alpha does not change.Therefore, in the related liquid crystal indicator of embodiment 1, the general who has surrendered becomes problem under the brightness during still image shows sometimes.
Therefore, the variation of the brightness of the pixel of the related liquid crystal indicator of this embodiment in the zone than hour, make the processing of the brightness of LED near the brightness of Max mode.Particularly; Area active drive handling part 15 the variation of brightness with the pixel in the zone be judged as than hour; Make alpha greater than once preceding; Provide greater than previous weight to maximal value Ma, provide less than previous weight, maximal value Ma and mean value Me are carried out weighted mean to mean value Me.
Fig. 8 is the process flow diagram that the coefficient decision of the related liquid crystal indicator of this embodiment is handled.。Coefficient decision shown in Figure 8 is handled and in step S15 shown in Figure 3, is carried out.Fig. 9 is the figure of example of the corresponding relation of mean value Me and alpha in the related liquid crystal indicator of this embodiment of expression.Below, maximal value Ma and the mean value Me that establishes the brightness of the pixel in the zone gets the value in 0 to 4095 the scope.
That kind as shown in Figure 9 is categorized as 16 grades with mean value Me.Maximal value Ma is categorized as 16 grades similarly.Below, establishing the affiliated grade of maximal value Ma is X, and the grade under the mean value Me is Y, and the pairing grade of alpha is Z.Area active drive handling part 15 is to (p * q) each color component in individual zone stores Three Estate X, Y, reaches Z.For example under number of degrees was 16 situation, area active drive handling part 15 stored (p * q * 3) individual 4 Bit datas.
That kind as shown in Figure 8, area active drive handling part 15 in coefficient decision is handled, obtain the grade X under the maximal value Ma that in step S14, is obtained and the mean value Me that in step S14, obtained under grade Y (step S21).
Then; Whether 15 couples of grade X of area active drive handling part and previous grade X (grade under the maximal value of the brightness of the pixel in the same area of previous frame) identical judges (step S22); Judge (step S23) to grade Y and previous grade Y (grade under the mean value of the brightness of the pixel in the same area of previous frame) be whether identical; Advance to step S24 having at least under the condition of different, under their all identical situation, advance to step S25.
Under the former situation, area active drive handling part 15 will be set at grade Z (step S24) by the grade Y that step S21 obtains.In the latter case, 15 couples of previous grade Z of area active drive handling part (when the same area of previous frame being carried out coefficient decision and handle, the grade that is set by step S24 or step S25) add 1 and are set at grade Z (step S25).But, make the value that is set at grade Z be no more than the maximal value (being 15 in this example) of grade.
Then, area active drive handling part 15 obtain with step S24 or step S25 in the corresponding alpha of grade Z (step S26) that sets.Then, area active drive handling part 15 Three Estate X will be when carrying out coefficient decision in the same area of next frame and handle included, that obtain by this processing, Y, and Z store (step S27).
For example, the maximal value Ma of brightness of the pixel in certain zone of previous frame is 2000, mean value Me is 1000 o'clock, and previous grade X is 7, and previous grade Y is 3.In addition, establishing previous alpha is 0.05, establish with the corresponding previous grade Z of alpha be 3.That the maximal value Ma of the brightness of the pixel in the same area of next frame remains is 2000 constant, mean value Me is changed under 1700 the situation, and grade X is identical with last time, but grade Y is changed to 6 from 3.In this case, grade Z is set at 6 in step S24, alpha is changed to 0.18 from 0.05.
Different therewith is, maximal value Ma is changed to 2040 in next frame, mean value Me is changed under 1020 the situation, and grade X becomes identical with last time with grade Y.In this case, grade Z is set at 4 in step S25, alpha is changed to 0.09 from 0.05.That maximal value Ma in next frame keeps is 2000 constant, mean value Me keeps under the 1000 constant situation, also identical with above-mentioned situation.
In addition; In Fig. 8; The grade Y of area active drive handling part 15 under grade X under the maximal value Ma and mean value Me the two all with last second phase simultaneously; The variation of brightness of the pixel in the zone is judged as less, but also can uses any means in addition, judge whether the variation of brightness of the pixel in the zone is less.
Below, the effect of the liquid crystal indicator that this embodiment is related is described.Here, that kind shown in figure 10, the situation of considering in the background of black, the still image of the zonule 52 of the white that comprised 1/10 area with zone 51 being shown.In this case, the maximal value Ma of the brightness of the pixel in the zone 51 is always 100%, and the mean value Me of the brightness of the pixel in the zone 51 is always 10%.
Figure 11 be expression when using Max mode, Mean mode and Mix mode to show picture shown in Figure 10, with the figure of the variation of the brightness of regional 51 corresponding LED.Showing with the Max mode under the situation of this picture, identical with the brightness of regional 51 corresponding LED with maximal value Ma, be always 100% (with reference to the dot-and-dash line of Figure 11).Showing with the Mean mode under the situation of this picture, identical with the brightness of regional 51 corresponding LED with mean value Me, be always 10% (with reference to the thick dashed line of Figure 11).Therefore, in the Max mode, can come show white, descend, can not come show white with correct brightness but in the Mean mode, produce brightness with correct brightness.
In the related liquid crystal indicator of this embodiment, handle the alpha that decides following formula (1) to be comprised according to coefficient decision shown in Figure 8.Thereby, under the situation that shows picture shown in Figure 10, even maximal value Ma and the mean value Me of the brightness of the pixel in the zone do not change, but with the corresponding grade Z of alpha along with the time through also becoming greatly gradually, become the maximal value 15 of grade at last.Alpha is also quickened to become big thereupon, becomes 1 at last.In addition, quicken brightness, arrive the brightness of Max mode at last near the Max mode with the brightness of regional 51 corresponding LED.
In the related liquid crystal indicator of this such embodiment; Even when the brightness of pixel in the zone does not change or the variable quantity of the brightness of the pixel in the zone than hour; But the brightness of LED23 to 25 also increases gradually, the final maximal value Ma that arrives the brightness of the pixel in the zone.Thereby, according to the liquid crystal indicator of this embodiment, can prevent fully that the brightness in still image shows from descending.
In addition, for the related liquid crystal indicator of embodiment 1 of the present invention and embodiment 2, can constitute various variation.For example, input picture 31 is that any in dynamic image or the still image is known under the situation about having, and then can expression input picture 31 be provided to liquid crystal indicator is the dynamic image or the signal of still image.In this case; When area active drive handling part 15 is rest image at input picture 31; The alpha that also can following formula (1) be comprised is as 1, and the brightness maximal value Ma based on the pixel in the zone obtains the brightness with this zone corresponding LED 23 to 25.Thus, can prevent fully at once that the brightness in the rest image demonstration from descending.
In addition, in embodiment 1 and 2, backlight 13 by red LED 23, green LED 24, and blue led 25 constitute, cold-cathode tube) but backlight also can be by White LED or cold-cathode tube (CCFL:Cold CathodeFluorescent Lamp: formation such as.At backlight is under the situation about being made up of White LED; The area active drive handling part if for example based on R image, G image, and the B image generate Y image (luminance picture); The Y image is carried out the step S11 to S17 in the processing shown in Figure 3, the image of three looks is carried out step S18 with the combination of Y image respectively get final product.
In addition, in embodiment 1 and 2, establish LED unit 22 and comprise a red LED 23, green LED 24 respectively, reach blue led 25, but the number of the LED of three looks that comprise in the LED unit 22 also can be a number in addition.For example, LED unit 22 also can comprise a red LED 23 and blue led 25, and two green LED 24 respectively.In this case, backlight source driving circuit 14 is as long as control the LED24 of two greens, makes that the summation of brightness of LED24 of two greens is that the LED brightness of following formula (1) gets final product.
In addition, the frame per second in the liquid crystal indicator can be arbitrarily, for example also can be 30Hz, 60Hz, 120Hz, reach more than the 120Hz.Because frame per second is high more, the brightness of LED changes with littler unit, so scintillation becomes more unshowy.In addition, through in comprising the image display device arbitrarily of backlight, using above-mentioned Mix mode, can obtain the effect identical with the situation of liquid crystal indicator.
As stated; According to image display device of the present invention; Through the two obtains the brightness with the light source of this corresponding backlight in zone based on maximal value and the mean value of the brightness of the pixel in the zone, can prevent scintillation and the brightness decline both of these case in the still image demonstration in dynamic image shows.
Practicality in the industry
Because image display device of the present invention has the scintillation that can prevent in dynamic image shows and the effect of the brightness decline both of these case in still image shows, therefore can be used for liquid crystal indicator etc., comprise the various image display devices of backlight.
1. image display device,
Have the function of the brightness of control backlight, it is characterized in that, comprising:
Display panel, this display panel comprises a plurality of display elements;
Backlight, this backlight comprises a plurality of light sources;
Signal processing part, this signal processing part are obtained demonstration with data and backlight control data based on input picture;
Panel drive circuit, this panel drive circuit is used data based on said demonstration, comes the signal to the light transmission of the said display element of said display panel output control; And,
Backlight source driving circuit, this backlight source driving circuit come the signal to the brightness of the said light source of said backlight output control based on said backlight control data,
Said signal processing part is when obtaining said backlight control data; Said input picture is divided into a plurality of zones; Obtain the maximal value and the mean value of the brightness of the pixel in each zone; The weight that changes according to said mean value is provided, obtains the brightness with each regional corresponding light source through said maximal value and mean value being carried out weighted mean
Said signal processing part provides the weight of the bigger variation of generation when said mean value is big more.
2. image display device as claimed in claim 1 is characterized in that,
Said signal processing part the variation of brightness with the pixel in the zone be judged to be than hour, provide greater than previous weight to said maximal value, provide less than previous weight to said mean value, said maximal value and said mean value are carried out weighted mean.
3. image display device as claimed in claim 1 is characterized in that,
When said signal processing part is still image at said input picture, obtain the brightness of said light source based on said maximal value.
4. method for displaying image,
Said method for displaying image is used for image display device, and said image display device comprises: comprise the display panel and the backlight that comprises a plurality of light sources of a plurality of display elements, said method for displaying image is characterised in that, comprising:
Use data based on said demonstration, come said display panel is exported the step of the signal of the light transmission of controlling said display element; And,
Based on said backlight control data, come said backlight is exported the step of the signal of the brightness of controlling said light source,
Obtain in the step of said demonstration with data and said backlight control data; When obtaining said backlight control data; Said input picture is divided into a plurality of zones, obtains the maximal value and the mean value of the brightness of the pixel in each zone, the weight that changes according to said mean value is provided; Obtain the brightness with each regional corresponding light source through said maximal value and mean value being carried out weighted mean
The weight of the bigger variation of generation is provided when said mean value is big more.
CN 200880104066 2007-10-25 2008-09-26 Image display device CN101785044B (en)
JP2007-277708 2007-10-25
JP2007277708 2007-10-25
PCT/JP2008/067382 WO2009054223A1 (en) 2007-10-25 2008-09-26 Image display device
CN101785044A CN101785044A (en) 2010-07-21
CN101785044B true CN101785044B (en) 2012-08-15
ID=40579330
CN 200880104066 CN101785044B (en) 2007-10-25 2008-09-26 Image display device
US (1) US20110115826A1 (en)
EP (1) EP2202718A4 (en)
JP (1) JPWO2009054223A1 (en)
CN (1) CN101785044B (en)
WO (1) WO2009054223A1 (en)
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2008-09-26 JP JP2009538029A patent/JPWO2009054223A1/en active Pending
2008-09-26 WO PCT/JP2008/067382 patent/WO2009054223A1/en active Application Filing
2008-09-26 CN CN 200880104066 patent/CN101785044B/en active IP Right Grant
2008-09-26 EP EP08842621A patent/EP2202718A4/en not_active Withdrawn
2008-09-26 US US12/674,750 patent/US20110115826A1/en not_active Abandoned
JPWO2009054223A1 (en) 2011-03-03
US20110115826A1 (en) 2011-05-19
EP2202718A1 (en) 2010-06-30
WO2009054223A1 (en) 2009-04-30
CN101785044A (en) 2010-07-21
EP2202718A4 (en) 2010-11-03
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