CN101587698A - Display apparatus, display control method, and display control program - Google Patents

Display apparatus, display control method, and display control program Download PDF

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Publication number
CN101587698A
CN101587698A CNA2009101429668A CN200910142966A CN101587698A CN 101587698 A CN101587698 A CN 101587698A CN A2009101429668 A CNA2009101429668 A CN A2009101429668A CN 200910142966 A CN200910142966 A CN 200910142966A CN 101587698 A CN101587698 A CN 101587698A
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brightness
flow rate
screen
value
image
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Chinese (zh)
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渡边秀和
行友英记
门胁泰仁
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Sony Corp
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Sony Ericsson Mobile Communications Japan Inc
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Abstract

A display apparatus includes a liquid crystal display element, a backlight, and a plurality of circuits conducting the following. A drive signal for driving the backlight is formed according to an adjustment value calculated from the one-screen average image luminance in the image signal for display and a predetermined linear luminance adjustment curve. An image signal amplification control is then conducted according to a linear image luminance correction curve specified by the adjustment value, the average luminance, and one or both of the one-screen minimum and maximum luminance values detected from the image signal. The corrected image is then supplied to the liquid crystal display element. In so doing, reduced power consumption is realized in the backlight of a liquid crystal display element while maintaining the image quality of displayed images.

Description

Display device, display control method and display control program
Technical field
The present invention relates to for example be installed in the display device in the miniaturized electronics such as mobile phone handsets, and control method of using in this display device and control program.
Background technology
LCD (LCD) is widely used as display element.Because liquid crystal itself is not self luminous, so will be provided with backlight usually for display image.
CCFL (Cold Cathode Fluorescent Lamp, cold-cathode fluorescence lamp) is backlight as the relatively large LCD that uses in the equipment such as TV mainly.But the power consumption in the lighting circuit of CCFL is bigger.
Therefore, need a kind of with size reduce, weight saving and power consumption be reduced to the backlight of feature, the LCD that installs with the miniaturized electronics that is used for such as mobile phone handsets.In addition, the relatively low white LEDs (white LED) of power consumption has been dropped into use as the backlight of LCD (LCD) of the display element that is used as PDA (personal digital assistant) recently.
But, go up the image quality in images that shows in order to keep LCD, a certain amount of at least electric current is flowed, to illuminate LCD in white LEDs backlight.The power consumption of LED backlight among the PDA is therefore bigger.
Therefore, come as since backlight, developed a large amount of and the reduction LCD relevant invention of power consumption backlight since introducing CCFL.
For example, the Japan not open No.H11-109317 of substantive examination patented claim discloses a kind of invention, it uses average picture intensity (the average picture level of the mean flow rate of expressing image, APL), be used as being used to utilize pulse-length modulation (PWM) signal controlling backlight illumination and be used for the basis that carries out image is proofreaied and correct (that is, picture signal strengthens).
More specifically, for example, shown in the A among Fig. 5, invention disclosed at first uses APL as being used for the basis that detection signal brightness is not more than the dark image of summary of mean value among the JP-A-H11-109317.Then, dim backlight for the dark image of detected like this summary.Simultaneously, according to the degree that is dimmed backlight, the picture signal (or vision signal) that forms this slightly dark image is enhanced, shown in the B among Fig. 5.
By aforesaid operations, invention disclosed can reduce backlight power consumption by carry out backlight intensity (backlight level) control (that is, dimming control) according to luminance signals among the JP-A-H11-109317.In addition, obtain bright image, thereby kept and the image visual that dims preceding same degree backlight by picture signal being strengthened by the degree that is dimmed backlight.
Summary of the invention
Disclosed foregoing invention is a kind of otherwise effective technique among the JP-A-H11-109317, because it has realized the power consumption reduction for LCD is backlight under the situation of not damaging shown image.But, have realized that and depend on image attributes that above-mentioned technology may not be worked in some cases effectively.
More detailed description: the given image that is used to show that is made of picture signal may be darker on the whole, but also may comprise incandescent (that is high brightness) image section in many cases.Empirical evidence if this picture signal just is enhanced by dimming degree backlight for this image simply, then utilizes the image of the picture signal demonstration that strengthens may seem not nature.
For example, shown in the A among Fig. 6, it is contemplated that a picture signal can be processed, wherein brightness of image integral body is lower, but has the high-brghtness picture images part at center Screen.When on lcd screen, showing the image that constitutes by the picture signal shown in the A among Fig. 6, backlight being dimmed, and picture signal is enhanced by the degree of dimming.
In this process, the hi-lite of being indicated by the arrow among the B among Fig. 6 is limited at 100% luminance signals place.In the case, the signal in the hi-lite (that is, the part of the picture signal that the above dotted line of 100% luminance signals intensity is indicated) changes to be lost, and the picture signal distortion that becomes.As a result, in this case, probably can not show the image of nature.
In addition, how many wherein brightness very low images without exception all of entire image normal video comprises usually hardly, even but comprise many dark on the whole but also brighter images of some part.Therefore,, it is contemplated that then that the actual headroom amount backlight (that is, offering the amount that power backlight can be lowered) that dims almost completely has been eliminated in picture signal to be processed if take measures to prevent the distortion of shown image.
Consider above situation and design the invention provides a kind of technology, by this technology, the characteristic that need not to depend on picture signal to be processed just can realize that the power consumption backlight of liquid crystal display cells reduces, and can carry out appropriate display to display image.
According to the solution of first embodiment of the invention a kind of display device of foregoing problems be provided with: liquid crystal display cells; The back lighting device that is used for liquid crystal display cells; The mean flow rate calculation element is used to calculate a screen mean flow rate of the represented image of the picture signal that is used to show; The regulated value calculation element is used for based on screen the average image brightness and the predetermined linear luminance adjustment curve from the mean flow rate calculation element, calculates the regulated value of the brightness that is used for regulating back lighting device; Drive signal forms device, is used for forming based on the regulated value that is calculated by the regulated value calculation element being used for making the drive signal that back lighting device is luminous, then resulting drive signal is offered back lighting device; The monochrome information pick-up unit is used for detecting one of a screen minimum image brightness of the picture signal that is used to show and a screen maximum image brightness or both; And image correction apparatus, be used for the mean flow rate that calculates based on the regulated value that calculates by the regulated value calculation element, by the mean flow rate calculation element and come the picture signal that is used to show carried out strengthening control, will offer liquid crystal display cells through the picture signal of overcorrect then by one of the detected minimum brightness of monochrome information pick-up unit and high-high brightness or linear image gamma correction curve that both are specified.
According to the display device of first embodiment of the invention, the regulated value calculation element uses a screen the average image brightness that is calculated by the mean flow rate calculation element, and predetermined linear luminance adjustment curve, calculates the regulated value of the brightness that is used to regulate back lighting device.Then, drive signal forms device and is formed for driving the drive signal of back lighting device according to the regulated value that calculates, and uses it to control the brightness of back lighting device.
In addition, come the picture signal that is used to show carried out based on a screen the average image brightness value that calculates by the mean flow rate calculation element, regulated value that the regulated value calculation element calculates and by one of the detected screen minimum image brightness of monochrome information pick-up unit and a screen maximum image brightness or both specified linear image gamma correction curves and strengthen control.
In this process, suitably carry out backlight intensity control based on the linear luminance adjustment curve, also suitably carry out enhancing control simultaneously to the picture signal that is used to show based on the linear image gamma correction curve of also having considered backlight intensity control.Therefore, realized that under the situation of the characteristic that does not rely on picture signal to be processed the power consumption backlight of liquid crystal display cells reduces, also under the situation that prevents the image visual reduction, suitably shown image simultaneously.
A kind of display device according to second embodiment of the invention is provided with: liquid crystal display cells; The back lighting device that is used for liquid crystal display cells; The mean flow rate calculation element is used to calculate a screen mean flow rate of the represented image of the picture signal that is used to show; Mean flow rate is averaged device, is used on multi-screen the screen mean flow rate from the mean flow rate calculation element being averaged; The regulated value calculation element is used for based on the mean value of the mean flow rate that is averaged device from mean flow rate and predetermined linear luminance adjustment curve, calculates the regulated value of the brightness be used for regulating back lighting device; Drive signal forms device, is used for forming based on the regulated value that is calculated by the regulated value calculation element being used for making the drive signal that back lighting device is luminous, then resulting drive signal is offered back lighting device; The monochrome information pick-up unit is used for detecting one of a screen minimum image brightness of the picture signal that is used to show and a screen maximum image brightness or both; Monochrome information is averaged device, is used to calculate by the detected minimum brightness of monochrome information pick-up unit at mean value that is averaged on the multi-screen and the mean value that is averaged on multi-screen by the detected high-high brightness of monochrome information pick-up unit; And image correction apparatus, be used for coming the picture signal that is used to show carried out at one of the minimum brightness that is averaged on the multi-screen and high-high brightness of on multi-screen, being averaged or both specified linear image gamma correction curves and strengthening control, will offer liquid crystal display cells through the picture signal of overcorrect then based on what the regulated value that is calculated by the regulated value calculation element, mean flow rate were averaged that the mean value of the mean flow rate that device calculates and monochrome information be averaged that device calculates.
Display device according to second embodiment of the invention, the regulated value calculation element is based on being averaged by mean flow rate that device is averaged on multi-screen a screen the average image brightness that is calculated by the mean flow rate calculation element and the value of the mean flow rate that obtains, and, calculate the regulated value of the brightness that is used to regulate back lighting device based on predetermined linear luminance adjustment curve.Then, drive signal forms device and is formed for driving the drive signal of back lighting device according to the regulated value that calculates, and uses it to control the brightness of back lighting device.
In addition, based on being averaged by mean flow rate that the value of device in a screen the average image brightness that is averaged on the multi-screen, regulated value that the regulated value calculation element calculates and monochrome information are averaged that device is averaged respectively on multi-screen one of the detected screen minimum image brightness of monochrome information pick-up unit and a screen maximum image brightness or both and one of the minimum brightness that obtains or high-high brightness or both specified linear image gamma correction curves come the picture signal that is used to show carried out and strengthen control.
In this process, suitably carry out backlight intensity control based on the linear luminance adjustment curve, also suitably carry out enhancing control simultaneously to the picture signal that is used to show based on the linear image gamma correction curve of also having considered backlight intensity control.
In addition, above-mentioned display device is configured to use the value of a screen mean flow rate that is averaged on multi-screen, and a screen minimum brightness that is averaged respectively on multi-screen and a screen high-high brightness.In this process, even the lcd controller of only interim memory image signal or similarly in the device therein also can suitably be carried out back lighting device brilliance control and picture signal and strengthen and control both.Therefore, also can handle the picture signal that is in the low frame rate state, thereby promote further power-saving.
Therefore,, realized that under the situation of the characteristic that does not rely on picture signal to be processed the power consumption backlight of liquid crystal display cells reduces, also under the situation that prevents the image visual reduction, suitably shown image simultaneously according to embodiments of the invention.
Description of drawings
Fig. 1 is the block diagram that is used to illustrate the display device of having used the embodiment of the invention;
Fig. 2 is the diagrammatic sketch that is used for illustrating the example of the linear luminance adjustment curve (that is linear APL-PWMGAIN curve) that the PWMGAIN counting circuit 107 of display device shown in Figure 1 100 uses;
Fig. 3 is used for illustrating that image calibrating circuit 104 in display device shown in Figure 1 100 is used for picture signal is carried out the diagrammatic sketch of example of the linear image gamma correction curve of brilliance control;
Fig. 4 is the block diagram that is used to illustrate another example of the display device of having used the embodiment of the invention;
Fig. 5 is the diagrammatic sketch that dims method backlight substantially that is used to illustrate prior art; And
Fig. 6 is the diagrammatic sketch that dims the problem of method backlight substantially that is used to illustrate prior art.
Embodiment
Below, embodiments of the invention will be described with reference to the drawings.As example, embodiment described below is applied to the display device that is installed in the mobile phone handsets, and wherein LCD is used as display element, and white LEDs to be used as LCD backlight.In addition, in the following detailed description, picture signal also is understood to include the common signal that forms a plurality of images of video sequence of expression.In other words, the picture signal here also can be a vision signal.In addition, the term here " intensity " (level) refers to picture signal or brightness backlight, is synonym with " brightness " here therefore.
(summary of the processing of carrying out in the display device)
In order to reduce backlight power consumption, carry out backlight intensity control according to the display device of embodiment described below, and picture signal strengthens control.But, should be understood that the display device according to embodiment described below is not to dim backlight simply or the enhancing picture signal.
Carry out the processing that combines following two classes processing according to the display device of embodiment described below.
(1) in backlight intensity control,, also control backlight so that it can excessively not dimmed and make image to seem not nature even under the lower situation of the mean flow rate of the expressed image of picture signal to be processed.
(2) in picture signal enhancing control, for the highlights and the dark portion change enhancing ratio of the formed image of picture signal, so that image is saturated and distortion is not obvious.
In this process, even when the picture signal that forms relatively brighter image is handled, also by dimming the reduction that suitable intensity has realized backlight power consumption with backlight.Simultaneously, prevented that by carrying out sensitively at picture signal to be processed to strengthen to control display image from seeming nature.
(exemplary configuration of display device)
Fig. 1 is the block diagram that is used to illustrate according to the configuration of the display device of present embodiment.As shown in Figure 1, the display device 100 of present embodiment is provided with picture signal input port 101, image quality improvement circuit 102 and lcd controller 103 (being labeled as LCDCTL in Fig. 1).
The display device 100 of present embodiment also is provided with image calibrating circuit 104, mean flow rate, minimum brightness (Min) and high-high brightness (Max) counting circuit 105 (below be referred to as the brightness calculation circuit), and parameter configuration register circuit 106.
In addition, the display device 100 of present embodiment also is provided with PWMGAIN (that is regulated value) counting circuit 107, PWM generative circuit 108, LCD panel 109, CPU (central processing unit) (CPU) 120 and keyboard 121.
Picture signal (that is Digital Image Data) via 101 inputs of picture signal input port at first is imported in image quality improvement circuit 102 and the brightness calculation circuit 105.For example, 102 pairs of processed picture signals of image quality improvement circuit are carried out various Flame Image Process, make to realize high-quality image replaying in the characteristic of the characteristic of considering picture signal and LCD panel 109.After 102 processing of image quality improvement circuit, picture signal is provided for lcd controller 103 subsequently.
Lcd controller 103 is made of the assembly such as video memory and LCD control circuit.The given picture signal that provides, lcd controller 103 forms the picture signal that is used for display image that is provided for LCD panel 109.The picture signal that is used to show that forms like this in lcd controller 103 is provided for image calibrating circuit 104 subsequently.
Image calibrating circuit 104 is regulated at the performed backlight illumination of the function of also considering the PWMGAIN counting circuit 107 that hereinafter will describe when handling (that is, backlight intensity control), and (or adjusting) proofreaied and correct in the brightness of the picture signal that provided.The picture signal of handling like this in image calibrating circuit 104 is provided for LCD panel 109 subsequently.
Simultaneously, a screen the average image brightness (that is average picture intensity (APL)) that provides the picture signal of coming to calculate single screen (that is frame) from picture signal input port 101 is provided brightness calculation circuit 105.In addition, brightness calculation circuit 105 also detects screen minimum image brightness (that is minimum picture intensity (Min)) and a screen maximum image brightness (that is maximum picture intensity (Max)).
A screen average picture intensity (APL), a screen minimum picture intensity (Min) and the maximum picture intensity of screen (Max) that brightness calculation circuit 105 is obtained are provided for PWMGAIN (that is backlight illumination regulated value) counting circuit 107 subsequently.
In addition, be used for seven parameters that the brightness backlight of LCD panel 109 is controlled are preconfigured in the register of parameter configuration register circuit 106, these parameters be via keyboard 121 input and set via CPU 120.
As shown in Figure 1, seven parameters here comprise minimum value (MIN) and the maximal value (MAX) of backlight intensity regulated value (PWMGAIN).
In addition, these seven parameters also comprise two threshold values of average picture intensity (APL): first threshold (the low threshold value of mean flow rate) and second threshold value (higher thresholds of mean flow rate).
In addition, these seven parameters also comprise three parameters relevant with the linear luminance adjustment curve of the practical adjustments value that is used to specify backlight illumination.These three parameters are low scope slope (LOW), middle scope slope (MIDDLE) and high scope slopes (HIGH), and wherein each parameter is respectively the basic, normal, high regional neutral line brightness regulation slope of a curve of dividing according to mean flow rate.
After in the register that is set at parameter configuration register circuit 106, above-mentioned seven parameters are provided for PWMGAIN counting circuit 107 subsequently.
In PWMGAIN counting circuit 107, based on a screen the average image brightness from brightness calculation circuit 105, and, calculate backlight intensity regulated value (PWMGAIN) from the linear luminance adjustment curve that seven parameters are determined that passes through of parameter configuration register circuit 106.
Then, PWMGAIN counting circuit 107 offers PWM generative circuit 108 with the backlight intensity regulated value (PWMGAIN) that is calculated.In addition, PWMGAIN counting circuit 107 offers image calibrating circuit 104 with the backlight intensity regulated value (PWMGAIN) that calculated with from three brightness correlations that brightness calculation circuit 105 receives.
Here, PWM generative circuit 108 from three brightness correlations that brightness calculation circuit 105 received and offered subsequently image calibrating circuit 104 is: a screen average picture intensity (APL), a screen minimum picture intensity (Min) and a screen maximum picture intensity (Max).
Based on the backlight intensity regulated value (PWMGAIN) that comes is provided from PWMGAIN counting circuit 107, PWM generative circuit 108 is formed for making the pwm signal of white LEDs backlight luminescence of LCD panel 109.PWM generative circuit 108 offers LCD panel 109 with this pwm signal subsequently.
LCD panel 109 is provided with LCD, is used as white LEDs backlight and the led drive circuit that is used for white LEDs.Led drive circuit is backlight according to providing the pwm signal that comes to drive white LEDs from PWM generative circuit 108.
Characteristic according to previously described processing (1), PWMGAIN counting circuit 107 calculates backlight intensity regulated value (PWMGAIN), when making mean flow rate when the expressed image of the picture signal of handling low, not backlight excessively not dimmed and the image nature that can not become.In this process, the brightness of serving as the white LEDs backlight of LCD panel 109 can be according to the image of handling and Be Controlled, and can excessively not dimmed.
Simultaneously, in image calibrating circuit 104, based on the enhancing amount that provides the parameter of coming to calculate the picture signal that is used for handling from PWMGAIN counting circuit 107, and to provide the picture signal of coming to carry out enhancement process from lcd controller 103.Then, the picture signal of enhancing is provided to the LCD of LCD panel 109.
According to the characteristic of previously described processing (2), the enhancing ratio of the highlights of 104 pairs of formed images of picture signal of image calibrating circuit and dark portion is made amendment, so that image is saturated and distortion is not obvious.In this process, the hi-lite of picture signal can excessively not strengthened, thereby makes high-quality image can be displayed on the lcd screen of LCD panel 109.
Like this, 100 pairs of the display device of present embodiment are served as the white LEDs backlight of LCD panel 109 and are carried out brilliance control, also picture signal are carried out simultaneously to strengthen control.
Below, will describe the processing of performed enhancing (that is, the proofreading and correct) picture signal of the processing of the performed calculating backlight intensity regulated value (PWMGAIN) of PWMGAIN counting circuit 107 in the display device 100 of present embodiment and image calibrating circuit 104 respectively in detail.
(PWMGAIN counting circuit 107 performed processing)
At first, the processing that the PWMGAIN counting circuit in the display device 100 of description present embodiment 107 is carried out.As previously mentioned, PWMGAIN counting circuit 107 provides the mean flow rate (APL) of coming to find the solution backlight intensity regulated value (PWMGAIN) by using from brightness calculation circuit 105.
Backlight intensity regulated value (PWMGAIN) can be considered to express lightness backlight, and this value is big more, backlight bright more.More specifically, suppose that backlight intensity regulated value (PWMGAIN) gets the value between 0.0 (minimum) and 1.0 (maximums), then 100% ground work backlight when PWMGAIN=1.0 (, brightness is 100%).
In addition, if the PWMGAIN counting circuit in the display device of present embodiment 100 107 calculates backlight intensity regulated value (PWMGAIN) according to average picture intensity (APL), then PWMGAIN counting circuit 107 calculates PWMGAIN based on linear luminance adjustment curve (that is linear APL-PWMGAIN curve).In the case, use seven pre-configured parameters.
These seven parameters are preconfigured in the register in the parameter configuration register circuit 106 in the display device 100.More specifically, these seven parameters comprise minimum value (MIN) and the maximal value (MAX) of backlight intensity regulated value (PWMGAIN), as previously mentioned.
These seven parameters also comprise the first threshold (lower limit of mean flow rate) and second threshold value (upper limit of mean flow rate) of average picture intensity (APL).In addition, these seven parameters also comprise three slope value of the linear luminance adjustment curve that is used to specify the practical adjustments value: hang down scope slope (LOW), middle scope slope (MIDDLE), high scope slope (HIGH) accordingly according to the basic, normal, high scope of linear luminance adjustment curve that the average image brightness is divided.
Fig. 2 is used for illustrating the PWMGAIN counting circuit 107 employed linear luminance adjustment curves (that is linear APL-PWMGAIN curve) of display device 100 of present embodiment and the diagrammatic sketch of the relation between above-mentioned seven parameters.
In Fig. 2, transverse axis is represented average picture intensity (APL), and Z-axis is represented backlight intensity regulated value (PWMGAIN).In addition, in Fig. 2, the linear luminance adjustment curve (that is linear APL-PWMGAIN curve) that linearity curve (A) expression is backlight.
As shown in Figure 2, linear luminance adjustment curve (A) utilizes above-mentioned seven parameters to come appointment, and these parameters are to come predetermined according to characteristic and the factor the picture quality state of a control such as LCD panel 109.
The maximal value and the minimum value of maximal value among Fig. 2 (MAX) and minimum value (MIN) expression backlight intensity regulated value (PWMGAIN).
In addition, the expression of first threshold among Fig. 2 (TH1) and second threshold value (TH2) is used to revise the APL point (that is, dividing the point of the definite scope of the average picture intensity (APL) of basis) of adjustment state backlight.
In addition, the low scope slope (LOW) among Fig. 2, middle scope slope (MIDDLE) and high scope slope (HIGH) are illustrated respectively in the slope of each preset range neutral line brightness regulation curve (A) of average picture intensity (APL), as previously mentioned.
Here, above-mentioned first threshold (TH1) and second threshold value (TH2) are separated the preset range of average picture intensity (APL).In the PWMGAIN counting circuit 107 of the display device 100 of present embodiment, first threshold (TH1) and second threshold value (TH2) are the APL points that is used for linear luminance adjustment curve (A) is divided into three scopes (that is zone).
At first, the scope of the average image brightness is to divide like this: low area is the scope less than the value of first threshold (TH1), middle zone is the scope of the value between first threshold (TH1) and second threshold value (TH2), and high zone is the scope greater than the value of second threshold value (TH2).
In addition, in the display device 100 of present embodiment, not simply backlight intensity regulated value (PWMGAIN) to be compared with average picture intensity (APL).As shown in Figure 2, in the basic, normal, high zone of separating, carry out different adjustings respectively by first threshold (TH1) and second threshold value (TH2) (that is APL point).In other words, the display device 100 of present embodiment is configured to and can carries out three grades of adjustings according to average picture intensity (APL).
More specifically, in the low scope of average picture intensity (APL), if backlight illumination (that is, light quantity) is excessively reduced, then image can seem strange.Therefore, the lower limit of backlight intensity regulated value (PWMGAIN) is set by the minimum value (MIN) of backlight intensity regulated value shown in Figure 2, thereby has prevented that backlight illumination from excessively being reduced.
In addition, if average picture intensity (APL) is present in the following low area of first threshold, then the unexpected variation of backlight illumination may can increase the not sense of nature on the contrary.Therefore, make the variation of backlight illumination keep less by low scope slope (LOW).Like this, in the time of in the low area below average picture intensity (APL) is present in first threshold (TH1), make backlight illumination increase (that is, increasing) gradually by smaller step size.
In addition, when average picture intensity (APL) is present in the middle zone between first threshold (TH1) and second threshold value (TH2), average picture intensity (APL) neither extremely low neither be high.
Therefore, when average picture intensity (APL) is present in the middle zone between first threshold (TH1) and second threshold value (TH2), control backlight illumination by middle scope slope (MIDDLE), so that change pro rata with the variation of average picture intensity (APL).
If average picture intensity (APL) is present in the above high zone of second threshold value (TH2), then the image saturated or distortion that may become.Consider this, limit the rising of backlight illumination by the maximal value (MAX) of backlight intensity regulated value.
In addition, when average picture intensity (APL) is present in the high zone more than second threshold value, improves backlight illumination significantly and be easy to cause the saturated and distortion of image.Therefore, make the variation of backlight illumination keep less by high scope slope (HIGH).Like this, in the time of in the high zone more than average picture intensity (APL) is present in second threshold value (TH2), also make backlight illumination increase (that is, increasing) gradually by smaller step size.
By following linear luminance adjustment curve shown in Figure 2 (A), as get off to find the solution corresponding backlight intensity adjustments value (PWMGAIN) in low area, middle zone and the high zone.
In the time of in the low area below average picture intensity (APL) is present in first threshold (TH1), multiply by average picture intensity (APL), add minimal adjustment value (MIN) then, calculate backlight intensity regulated value (PWMGAIN) by hanging down scope slope (LOW).
When average picture intensity (APL) is present in the middle zone between first threshold (TH1) and second threshold value (TH2), by middle scope slope (MIDDLE) being multiply by this regional the average image brightness (APL-TH1), add the regulated value (PWMGAIN) of first threshold (TH1) then, calculate backlight intensity regulated value (PWMGAIN).
In the time of in the high zone more than average picture intensity (APL) is present in second threshold value (TH2), by high scope slope (HIGH) being multiply by this regional the average image brightness (APL-TH2), add the regulated value (PWMGAIN) of second threshold value (TH2) then, calculate backlight intensity regulated value (PWMGAIN).
In this process, even when average picture intensity (APL) when increasing to high strength, also backlight intensity regulated value (PWMGAIN) is remained and be less than or equal to predetermined maximum value (Max), as shown in Figure 2.
In addition, even, also backlight intensity regulated value (PWMGAIN) is remained and is equal to or greater than predetermined minimum value (MIN), as shown in Figure 2 when average picture intensity (APL) when being reduced to low-intensity.
In addition, when average picture intensity (APL) is present in the above high part (that is, high zone) of lower part (that is, low area) below the first threshold (TH1) or second threshold value (TH2), make the variation of backlight intensity regulated value (PWMGAIN) keep less.
When average picture intensity (APL) is present in the part between the first threshold and second threshold value, control backlight intensity regulated value (PWMGAIN) pro rata with the average image brightness.
By to the above-mentioned a series of controls of execution backlight, realized the reduction of backlight power consumption.In addition, the influence that the image that the variation of backlight illumination upward shows LCD applies has been reduced, thereby has prevented that LCD from going up the image that shows and seeming nature.
In other words, backlight illumination is retained as on the whole and is equal to or less than maximal value (MAX), and in the part below the average image brightness is present in first threshold (TH1) time, backlight illumination also is maintained near minimum value backlight (MIN).Therefore, realized the reduction of power consumption backlight.
In addition, owing to the variation of backlight illumination is remained in the part when average picture intensity (APL) is present in first threshold (TH1) below the time lessly, so prevented that shown image from seeming naturally.In addition, owing to similarly the variation of backlight illumination is remained in the part when average picture intensity (APL) is present in second threshold value (TH2) more than the time lessly, so also can reduce saturated and distortion effect.
In addition, when the average image brightness is present in the scope between first threshold (TH1) and second threshold value (TH2), control backlight illumination, thereby can not make the image of demonstration seem nature according to average picture intensity (APL).
Like this, in the display device 100 of present embodiment, used the linear luminance adjustment curve (A) that as described in, forms, thereby made it possible to come the suitably regulated value (that is backlight brightness values) of definite backlight illumination based on average picture intensity (APL) with reference to figure 2.
Should be understood that it is that cost preferentially reduces power consumption slightly secretly that display device 100 can be configured to shown image by regulating aforesaid seven parameters.On the contrary, display device 100 can be configured to also reduce with power consumption that not to be evident as so that cost comes with picture quality serve as preferential.
In addition, actual seven parameters using also can be modified according to the characteristic and the picture quality state of a control of employed LCD panel.In the display device 100 of the present embodiment here, seven above-mentioned parameters are based on and are used for coming the repeated experiments of optimization setting and preassigned at LCD panel or employed other assemblies.
Aforesaid low scope slope (LOW) and high scope slope (HIGH) are understood such slope here, and these slopes limit the slope of the rate of change of the rate of change that is not more than mean flow rate.Basically, low scope slope (LOW) and high scope slope (HIGH) are got and are less than or equal to 1 value.More specifically, low scope slope (LOW) and the desirable value such as 0.5 and 0.7 of high scope slope (HIGH).
In addition, middle scope slope (MIDDLE) is understood that proportional with the rate of change of mean flow rate here.More specifically, middle scope slope (MIDDLE) get near or equal 1 value, and desirable in some cases greater than 1 value.
Here, two threshold values (first threshold and second threshold value) of average picture intensity (APL) are used to the average image brightness domain is divided into three zones (low area, middle zone and high zone).Be that the slope of linear luminance adjustment curve (A) is set in each zone subsequently, and use it to carry out the backlight illumination adjusting.But the present invention is not limited to said circumstances.
Also may set single threshold value, thereby the average image brightness domain is divided into two zones (low area and high zone) for average picture intensity.Be the slope of each the setting linear luminance adjustment curve (A) in these two zones then, and use it to carry out the backlight illumination adjusting.
Can also set three or more threshold values for average picture intensity, thereby average picture intensity domain is divided into four or more a plurality of zone.Be that in these four or the more a plurality of zone each is set the slope of linear luminance adjustment curve (A) then, use it to carry out backlight illumination then and regulate.
In other words, the number of the threshold value of average picture intensity is not limited to two.Can provide one or more threshold values in the time of suitably, so that can suitably carry out the backlight illumination adjusting according to characteristic or other factors of display device.
(image calibrating circuit 104 performed processing)
The performed processing of image calibrating circuit 104 in the display device 100 of present embodiment will be described now.In conjunction with the backlight intensity control that above-mentioned PWMGAIN counting circuit 107 is carried out, image calibrating circuit 104 carries out image signals strengthen control, so that prevent that LCD from going up the image that shows and seeming not nature.
There are many situations as previous with reference to as described in figure 5 and Fig. 6, that is, when the degree that just is lowered according to backlight illumination simply when the picture signal that forms image is enhanced, the image quality in images reduction of the last demonstration of LCD.In particular, when enhancing has the image section of high brightness, the saturated and distortion of picture signal takes place.
Therefore, given picture signal to be processed, image calibrating circuit 104 in the display device 100 of present embodiment is set bigger enhancing ratio for the corresponding part of the image section with having relatively low brightness of picture signal, and sets less enhancing ratio for the corresponding part of the image section with having relative higher brightness of picture signal.
In this process, can carry out the two-stage brilliance control to the brightness of picture signal.The brilliance control of picture signal is based on is scheduled to or the linear image gamma correction curve of configuration automatically carries out.
Fig. 3 is the diagrammatic sketch of the example of the image calibrating circuit 104 that is used for illustrating the display device 100 of the present embodiment linear image gamma correction curve that is used for the control of carries out image luminance signals.
In Fig. 3, transverse axis is represented the brightness value Yin of received image signal, and Z-axis is represented the brightness value Yout of output image signal.In addition, the linearity curve (B) that is shown solid line among Fig. 3 is the linear image gamma correction curve that is used for the brightness of image signal correction.The slope that is shown the linearity curve (C) of dotted line among Fig. 3 is 1, is used for comparison.
As shown in Figure 3, in the time of in the part below received image signal brightness value Yin is present in predetermined flex point IX (INFLEXTION_X), the slope of linear image gamma correction curve (B) becomes low-light level slope (LOWER).When received image signal brightness value Yin is present in when being equal to or higher than predetermined flex point IX (INFLEXTION_X) middle, slope becomes high brightness slope (UPPER).
Except low-light level slope (LOWER) and high brightness slope (UPPER), also there are basic brightness BY (BASE_Y) and aforesaid flex point IX (INFLEXTION_X).
Basic brightness BY (BASE_Y) is used for being fixed as 0 in the value of input signal brightness value Yin near 0 o'clock value with output signal brightness value Yout, thereby it is black to make that the user can be felt as the blackboard branch of image, and it is strange can not seem.
Basic brightness BY (BASE_Y) thus be fixed as 0 in the value of input signal brightness value Yin near 0 o'clock value with output signal brightness value Yout.As a result, the user can be with black the black of nature that be felt as on the display screen.
As previously mentioned, the flex point of the slope of flex point IX (INFLEXTION_X) expression linear image gamma correction curve (B).In other words, linear image gamma correction curve (B) becomes low-light level slope (LOWER) in brightness value is lower than the part of flex point IX (INFLEXTION_X).In addition, the slope of linear image gamma correction curve (B) becomes high brightness slope (UPPER) in brightness value is higher than the part of flex point IX (INFLEXTION_X).
Above four parameters of manual configuration in advance.But, also can be configured to four parameters automatically, hereinafter will be described in detail this.By using above four parameters, can change brightness of image correcting state (that is, strengthening the state of control) at the picture signal of handling.
In addition, by following linear image gamma correction curve (B) shown in Figure 3, as get off to find the solution brightness of image in the part that brightness of image in the part that brightness value is lower than flex point IX (INFLEXTION_X) and brightness value be higher than flex point IX (INFLEXTION_X).
When input signal brightness value Yin is present in the zone that is lower than flex point IX (INFLEXTION_X), by low-light level slope (LOWER) be multiply by input signal brightness value Yin, add basic brightness BY (BASE_Y) then, calculate output signal brightness value Yout.
When input signal brightness value Yin is present in the zone that is equal to or higher than flex point IX (INFLEXTION_X), by high brightness slope (UPPER) be multiply by input signal brightness value Yin and flex point IX (INFLEXTION_X) (promptly, its brightness value) poor between, add flex point IX (INFLEXTION_X) then, calculate output signal brightness value Yout.
In linear image gamma correction curve (B) shown in Figure 3, in fact the enhancing ratio with picture carrier is identical can to think slope.Therefore, at the bigger part of slope (that is, low-light level slope (LOWER))) in, it is higher to strengthen ratio.On the contrary, in the less part of slope (that is, high brightness slope (UPPER)), it is lower to strengthen ratio.Therefore, when slope (in the part of high brightness slope (UPPER) shown in Figure 3 is exactly like this) less than 1 the time, brightness of image changes on the decay direction.
Under the situation of picture signal, the high improvement that strengthens ratio corresponding to contrast.Therefore, though improved contrast for the low brightness values among Fig. 3, for the higher part of brightness, possible degradation in contrast.
But as previously mentioned, handling (that is, picture signal strengthens control) for the two-stage image gamma correction of picture signal is to carry out according to linear image gamma correction curve (B) shown in Figure 3.In this process, can suppress the influence that treatment for correcting applies the hi-lite of picture signal.As a result, prevented that image from seeming not nature.
In other words,, leniently strengthen brightness of image, thereby prevented the negative effect such as the saturated and shown image fault of picture signal, and shown high quality graphic for the higher part of brightness in the image.
(being used to specify the concrete grammar of parameter)
Use description to the method for four parameters (that is, low-light level slope (LOWER), high brightness slope (UPPER), basic brightness BY (BASE_Y) and flex point IX (INFLEXTION_X)) of use in the specify image correcting circuit 104 now.
For four parameters using in the image calibrating circuit 104, can find out and set suitable value in advance by experiment.Can also investigate the attribute of image input by software processes or similar means in advance, set above four parameters according to result then.
But, the picture carrier treatment for correcting of carrying out in the image calibrating circuit 104 preferably with PWMGAIN counting circuit 107 in the LCD backlight intensity control carried out carry out explicitly.
Therefore, in the image calibrating circuit 104 of the display device 100 of present embodiment, low-light level slope (LOWER) is based on that the backlight intensity regulated value (PWMGAIN) that calculates in the PWMGAIN counting circuit 107 determines.
In addition, high brightness slope (UPPER) and basic brightness BY (BASE_Y) are based on a screen average picture intensity (APL) and a screen minimum (Min) and maximum (Max) picture intensity and determine.
In case determined above three parameters, just can utilize these three parameters to find the solution flex point IX (INFLEXTION_X) by simple calculating.
Below, the concrete grammar that uses description to specify low-light level slope (LOWER), high brightness slope (UPPER), basic brightness BY (BASE_Y) and flex point IX (INFLEXTION_X).
At first, use description to specify the method for low-light level slope (LOWER).Low-light level slope (LOWER) is so set in PWMGAIN counting circuit 107, so that the degree that degree that input signal strength is exaggerated and backlight intensity are lowered is suitable.More specifically, if backlight intensity be lowered to intensity p (=PWMGAIN), input signal strength then is multiplied by 1/p=p -1
But in the practice, the image that shows on the LCD panel 109 also is carried out gamma correction.Here, with the typical gamma value 2.2 in the consideration LCD panel and the situation of basic backlight intensity 1.0 (100%).In addition, the unit of backlight intensity and picture intensity (that is brill) is cd/m here 2, " nit " in other words.
In the case, if backlight intensity is reduced to intensity p relatively, then the surface brightness Y ' that has under the situation of image of same pixel intensity in demonstration can utilize original brightness Y to be expressed as Y '=Yp 1/2.2In other words, 1/2.2 power that can multiply by backlight intensity p by the original brightness Y with image is found the solution surface brightness Y '.
Therefore, in the display device 100 of present embodiment, by to Y '=Yp 1/2.2Carry out inversion and bring setting low-light level slope (LOWER).In other words, low-light level slope (LOWER) is set to p -1/2.2(-1/2.2 power of p).Clearly, low-light level slope (LOWER) is not limited to this value, but can be set to other appropriate value according to employed concrete gamma value.
Simultaneously, set high brightness slope (UPPER), to get the value in the scope between 0.65 to 1.0 according to the value of screen average picture intensity (APL) and the maximum picture intensity of screen (Max) by using display device 100 to experimentize.
Therefore, based on screen average picture intensity (APL) and a screen maximum picture intensity (Max), set up the single value that a table determines to belong to the high brightness slope (UPPER) of the scope between 0.65 to 1.0.The table here is in the predetermined memory zone that is based upon in advance in the image calibrating circuit 104.
As a result, for example, if one the screen average picture intensity (APL) value be a, and one the screen maximum picture intensity (Max) value be b, then the value of high brightness slope (UPPER) is 0.65.Like this, determined high brightness slope (UPPER) uniquely by average picture intensity (APL) and maximum picture intensity (Max).
Set basic brightness BY (BASE_Y) by using display device 100 to experimentize, to get the value in the scope between 0 to-22 according to the minimum picture intensity of screen (Min).
Therefore, based on a screen minimum picture intensity (Min), set up the single value that a table determines to belong to the basic brightness BY (BASE_Y) of the scope between 0 to-22.Above-mentioned table is based upon in the predetermined memory zone in the image calibrating circuit 104 similarly in advance.
As a result, if the value of the minimum picture intensity of screen (Min) is c, then the value of basic brightness BY (BASE_Y) is-5.0.Like this, determined basic brightness BY (BASE_Y) uniquely by the minimum picture intensity of screen (Min).
Should be understood that basic brightness BY (BASE_Y) is not limited to only determine by the minimum picture intensity of screen (Min), but can certainly determine by the combination of screen minimum picture intensity (Min) and average picture intensity (APL).
Can be by finding the solution flex point IX (INFLEXTION_X) based on the calculating of above three parameters (that is, low-light level slope (LOWER), high brightness slope (UPPER) and basic brightness BY (BASE_Y)).
More specifically, the linear image gamma correction curve (B) that is lower than in the zone of flex point IX of input signal brightness value Yin is represented by following formula 1.
The basic brightness BY of Yout=low-light level slope (LOWER) * input signal brightness value Yin+ (1)
In addition, input signal brightness value Yin is higher than linear image gamma correction curve (B) in the zone of flex point IX by representing with following formula 2.
Intercept m (2) on Yout=high brightness slope (UPPER) * input signal brightness value Yin+Yout axle
Here, if the maximal value of picture intensity is taken as 1.0 (that is, 100% brightness), then when the value of input signal brightness value Yin was 1.0, output signal brightness value Yout also became 1.0.Therefore, can utilize with following formula 3 and find the solution intercept m on the Z-axis (that is Yout axle).
Intercept m=1.0-low-light level slope (LOWER) (3) on the Yout axle
Under the situation that above-mentioned formula 1 and formula 2 equates (that is, the position that the line in formula 1 and formula 2 intersects), the flex point IX that find the solution (INFLEXTION_X) thus equal the value of input signal brightness value Yin.
Can determine low-light level slope (LOWER) like this based on regulated value (PWMGAIN) from the PWMGAIN counting circuit.
In addition, can be by based on average picture intensity (APL) and maximum picture intensity (Max) or based on minimum picture intensity (Min), with reference to the information in the table of setting up in advance, determine high brightness slope (UPPER) and brightness BY (BASE_Y) substantially like this.
In addition, can find the solution flex point IX (INFLEXTION_X) like this by calculating based on above three definite parameters (that is, low-light level slope (LOWER), high brightness slope (UPPER) and basic brightness BY (BASE_Y)).
Utilize such designated parameters, based on the screen of one in the picture signal of handling luminance correlation information, and backlight intensity regulated value (PWMGAIN), for each screen has been specified optimum linear image gamma correction curve (B).
Based on the linear image gamma correction curve (B) of such appointment, can carry out suitably to strengthen to input signal and control.
Here, above-mentioned low-light level slope (LOWER) and the ratio that is varied to of handling the brightness of image of image.More specifically, low-light level slope (LOWER) can near or equal 1, and desirable in some cases greater than 1 value.Simultaneously, high brightness slope (UPPER) is less than or equal to the variation of the brightness of image of the image of handling.Basically, high brightness slope (UPPER) is got and is less than or equal to 1 value.More specifically, high brightness slope (UPPER) is got the value such as 0.5 and 0.7.
From description, can know and find out that PWMGAIN counting circuit 107 and image calibrating circuit 104 can suitably be regulated the backlight illumination of LCD panel 109, thereby reduce backlight power consumption the display device 100 of previous embodiment.In addition, owing in backlight intensity control, also suitably controlled the brightness of the picture signal of handling, therefore can the shown image of deterioration.
Utilize the display device 100 of present embodiment, confirm by experiment, when showing the rest image of common landscape or portrait, compare, power consumption can be reduced by 20% to 50% with the display device of prior art.In addition, confirm,, when display video, power consumption can be reduced about 30% to 80% because video has a large amount of relatively this characteristics of dark image section.
In the display device 100 of present embodiment, can suitably carry out backlight intensity control and picture signal enhancing control based on the simple parameter such as average picture intensity (APL), minimum picture intensity (Min) and maximum picture intensity (Max).
In addition, can utilize the relative small-scale circuit such as image calibrating circuit 104, brightness calculation circuit 105, parameter configuration register circuit 106 and PWMGAIN counting circuit 107 to carry out backlight intensity control and picture signal enhancing control.
Because it is relative less with the scale that picture signal strengthens the circuit of controlling to carry out backlight intensity control, so it is also lower to be used for the power of image rectification, thereby embodiments of the invention can be installed in series after lcd controller, even also be like this in high frame rate device.
In other words, the display device 100 of present embodiment has realized that by following a kind of novelty and relative simple algorithm backlight emission control and picture signal strengthen control, and also can not increase the scale of circuit.
In display device shown in Figure 1 100, image calibrating circuit 104, brightness calculation circuit 105, parameter configuration register circuit 106 and PWMGAIN counting circuit 107 are deployed in after the LCDCTL 103.
Therefore, in display device shown in Figure 1 100, be used in subsequently among the LCDCTL 103 by image quality improvement circuit 102 handled picture signals, be provided for the picture signal that is used to show of LCD panel 109 with formation, this picture signal that is used for showing was accumulated in storer subsequently before being provided for image calibrating circuit 104.
Therefore, the processing in brightness calculation circuit 105, parameter configuration register circuit 106 and the PWMGAIN counting circuit 107 is to carry out when picture signal is processed in image quality improvement circuit 102 and LCDCTL103.
As a result, processing in the image calibrating circuit 104 and the processing in the PWM generative circuit 108 are carried out simultaneously.Therefore, more than configuration make according to pwm signal carry out to the backlight drive control that causes by brilliance control of LCD panel 109 can with above-mentioned display device 100 in synchronous by strengthening the picture signal display process that control causes.
In the image calibrating circuit 104 in the display device 100 of the present embodiment of describing referring to figs. 1 to Fig. 3, basic brightness BY (BASE_Y) is based on that the minimum picture intensity of screen (Min) disposes.But, should be understood that at basic brightness BY (BASE_Y) to be set under the situation of fixed value, can omit finding the solution to a screen minimum picture intensity (Min).
Therefore, under above situation, can only find the solution a screen maximum picture intensity (Max), can utilize maximum picture intensity (Max) and average picture intensity (APL) suitably to find the solution high brightness slope (UPPER) then.
In addition, for example, can high brightness slope (UPPER) be set under the situation of fixed value, can omit finding the solution a screen maximum picture intensity (Max) by the test in advance of display device 100.
Therefore, under above situation, only find the solution a screen minimum picture intensity (Min), suitably find the solution basic brightness BY (BASE_Y) based on minimum picture intensity (Min) then.
Like this, be set under the situation of fixed value, can find the solution screen minimum picture intensity (Min) or a screen maximum picture intensity (Max) so that determine not to be set to another parameter of fixed value at high brightness slope (UPPER) or basic brightness BY (BASE_Y).
(variant)
Simultaneously, even for video, the frame rate of the content of mobile phone handsets also is approximately 5FPS to 30FPS (frame per second).But the frame rate of the video behind the lcd controller is enhanced about 60FPS.
On the principle, this raising of carrying out frame rate is in order to keep higher picture quality, and wherein, the view data that is used for the image demonstration that is formed by lcd controller provides identical picture signal to LCD repeatedly, till the picture signal of new images is provided.
As previously mentioned and since one embodiment of the present of invention have on a small scale circuit and lower control related power consumption, even therefore after being applied to lcd controller the time, this embodiment also is favourable.But in some cases, embodiments of the invention can be used in before the lcd controller, so that further suppress the power draw of circuit.
Therefore, the display device 200 of the variant according to the embodiment of the invention described below is configured to carry out backlight intensity control and picture signal and strengthens and control before lcd controller.
Fig. 4 is the block diagram that is used to illustrate according to the display device 200 of this variant.As shown in Figure 4, the display device 200 of this example is provided with picture signal input port 201, image quality improvement circuit 202 and lcd controller 203 (being labeled as LCDCTL in Fig. 4).
The display device 200 of this example also is provided with image calibrating circuit 204, mean flow rate, minimum brightness (Min) and high-high brightness (Max) counting circuit 205 (below be referred to as the brightness calculation circuit), and parameter configuration register circuit 206.
In addition, the display device 200 of this example also is provided with PWMGAIN (that is regulated value) counting circuit 207, PWM generative circuit 208, LCD panel 209, luminance parameter interframe and is averaged circuit 210, CPU (central processing unit) (CPU) 220 and keyboard 221.
Here, among the circuit that is provided with in the display device 200 shown in Figure 4 with display device 100 shown in Figure 1 in each circuit of circuit corresponding (that is, same names being arranged) have and the similar function of describing with reference to display device shown in Figure 1 100 of related circuit.
But, when display device more shown in Figure 4 200 and display device 100 shown in Figure 1, can recognize, there are following two significant differences.
At first, display device 200 shown in Figure 4 is that with the significant difference of display device 100 shown in Figure 1 image calibrating circuit 204, brightness calculation circuit 205, parameter configuration register circuit 206 and PWMGAIN counting circuit 207 are set at before the LCDCTL 203.
Next, display device 200 shown in Figure 4 is that with the difference of display device 100 shown in Figure 1 display device 200 comprises that also the luminance parameter interframe between brightness calculation circuit 205 and PWMGAIN counting circuit 207 is averaged circuit 210.
In display device shown in Figure 4 200, luminance parameter interframe is averaged circuit 210 makes the assembly such as image calibrating circuit 204 and PWMGAIN counting circuit 207 can be set at before the LCDCTL 203.
More specifically, under the situation of display device shown in Figure 1 100, image calibrating circuit 104, brightness calculation circuit 105, parameter configuration register circuit 106 and PWMGAIN counting circuit 107 are set at after the LCDCTL 103.
Therefore, the circuit such as PWMGAIN counting circuit 107 can play a role during picture signal remains in period among the LCDCTL 103 and this picture signal is carried out backlight intensity control and picture signal and strengthen and control, as previously mentioned.
Different with it, under the situation of display device 200 shown in Figure 4, the circuit such as image calibrating circuit 204 and PWMGAIN counting circuit 207 is set at before the LCDCTL 203.Therefore, before the picture signal from 202 outputs of image quality improvement circuit was provided for image calibrating circuit 204, the mean flow rate of given picture signal, minimum brightness and high-high brightness and regulated value backlight (PWMGAIN) were not calculated.
Therefore, in display device shown in Figure 4 200, luminance parameter interframe is averaged circuit 210 and finds the solution brightness calculation circuit 205 has for example calculated two most recent of average picture intensity (APL) for it the mean value of average picture intensity (APL) of frame.
More specifically, luminance parameter interframe is averaged mean value, the mean value of minimum picture intensity (Min) and the mean value of maximum picture intensity (Max) of average picture intensity (APL) that circuit 210 calculates the frame of two most recent, then the result is offered PWMGAIN counting circuit 207.
PWMGAIN counting circuit 207 uses the mean value that is averaged the average picture intensity (APL) of circuit 210 from luminance parameter interframe to calculate backlight intensity regulated value (PWMGAIN) then.In other words, the function of PWMGAIN counting circuit 207 is identical with PWMGAIN counting circuit 107 shown in Figure 1, only wherein is not to use average picture intensity (APL), rather than uses the mean value of average picture intensity (APL).
Therefore, in PWMGAIN counting circuit 207 shown in Figure 4, the linear luminance adjustment curve of describing with reference to figure 2 (A) seven parameters providing from parameter configuration register circuit 206 is provided comes appointment.
In addition, in PWMGAIN counting circuit 207, backlight intensity regulated value (PWMGAIN) is to provide the mean value of the average picture intensity (APL) of coming to calculate according to be averaged circuit 210 from luminance parameter interframe, is provided for PWM generative circuit 208 then.
Similar with PWM generative circuit 108 shown in Figure 1, PWM generative circuit 208 is according to providing the regulated value (PWMGAIN) that comes to form pwm signal from PWMGAIN counting circuit 207, and the LED that then this pwm signal is offered LCD panel 209 drives.In this process, can carry out brilliance control to serving as LED backlight.
Simultaneously, PWMGAIN counting circuit 207 offers image calibrating circuit 204 with the backlight intensity regulated value (PWMGAIN) that calculates, and also will offer image calibrating circuit 204 from the luminance correlation information that luminance parameter interframe is averaged circuit 210 simultaneously.
Also illustrate as Fig. 4, the luminance correlation information here comprises the interframe mean value (Min (avg.)) of the interframe mean value (APL (avg.)) of average picture intensity (APL), minimum picture intensity and the interframe mean value (Max (avg.)) of maximum picture intensity.
Similar with image calibrating circuit 104 shown in Figure 1, image calibrating circuit 204 is specified based on four parameters describing with reference to figure 3 will be to providing the linear image gamma correction curve (B) of the picture signal use that comes from image quality improvement circuit 202.
Then, image calibrating circuit 204 uses the linear image gamma correction curve (B) of appointment to come provide the picture signal of coming to carry out enhancing control from image quality improvement circuit 202 based on next information is provided from PWMGAIN counting circuit 207.The picture signal that strengthens after controlling is provided for LCDCTL 203 subsequently.
LCDCTL 203 is subsequently according to provide the picture signal through strengthening control of coming to form the picture signal that will be provided for LCD panel 209 from image calibrating circuit 204.The picture signal that obtains thus is provided for LCD panel 209 subsequently.
In this process, be displayed on the lcd screen of LCD panel 209 with the corresponding image of controlling through enhancing of picture signal.In addition, the LED backlight of LCD panel 209 is created the pwm signal of controlling backlight illumination and drives.
Therefore, the display device 200 of this variant shown in Figure 4 also can suitably be carried out backlight intensity control according to the linear luminance adjustment curve of describing with reference to figure 2 (that is linear APL-PWMGAIN curve) similarly.
Simultaneously, display device 200 can also come the picture signal that will show is carried out enhancing control according to the linear image gamma correction curve of describing with reference to figure 3.
Like this, even when the circuit according to the embodiment of the invention is set at before the LCDCTL 203, also can suitably carry out backlight intensity control, and can realize the reduction of backlight power consumption.
In addition, owing to also can control the enhancing control of suitably carrying out the picture signal that will show, therefore can show high-quality image, and can not produce the saturated or distortion of image according to backlight intensity.
In addition, under the situation of display device shown in Figure 4 200, the circuit such as image calibrating circuit 204 and PWMGAIN counting circuit 207 can be set at before the LCDCTL 203.As a result, can carry out backlight intensity control and picture signal enhancing control to the picture signal before being handled with relatively low frame rate by LCDCTL 203.Therefore, can prevent that backlight intensity control and picture signal from strengthening the power consumption that relates in the control and becoming excessive.
Here, in the scope of processing time permission, the luminance parameter interframe in the variant shown in Figure 4 is averaged circuit 210 and also can be configured to more a plurality of frames are found the solution mean value.In addition, luminance parameter interframe is averaged the weighted mean that circuit 210 also can be configured to use a plurality of frames certainly.
In variant shown in Figure 4, the mean value of 207 pairs of average picture intensity of PWMGAIN counting circuit (APL) uses the first threshold and second threshold value, thereby the territory of the mean value of average picture intensity is divided into three zones: low area, middle zone and high zone.Then each zone is set the slope of linear luminance adjustment curve (A), used it to regulate backlight illumination then.But the present invention is not limited to this.
Can also be only the mean value of average picture intensity be set a threshold value, thereby the territory of the mean value of average picture intensity is divided into two zones: low area and high zone.Can be each zone then and set the slope of linear luminance adjustment curve (A), and can use it to regulate backlight illumination subsequently.
In addition, can also be that the mean value of average picture intensity is set three or more threshold values, thereby the territory of the mean value of average picture intensity is divided into four or more a plurality of zone.Each that can be then in these four or the more a plurality of zone is set the slope of linear luminance adjustment curve (A), and can use it to carry out backlight illumination subsequently and regulate.
In other words, the number of the threshold value of the mean value of average picture intensity is not limited to two.Can provide one or more threshold values in the time of suitably, so that can suitably carry out the backlight illumination adjusting according to characteristic or other factors of display device.
Here, the variant of describing with reference to figure 4 is configured to use the mean value of the mean value of average picture intensity, minimum picture intensity and the mean value of maximum picture intensity.But, in theory, more than being equivalent to use average picture intensity (APL), minimum picture intensity (Min) and maximum picture intensity (Max), this situation with the display device of describing with reference to figure 1 100 is similar.
In addition, in variant shown in Figure 4, image calibrating circuit 204 is configured to dispose basic brightness BY (BASE_Y) based on the mean value of the minimum picture intensity of screen (Min).But, be set at basic brightness BY (BASE_Y) and can omit finding the solution under the situation of fixed value the mean value of the minimum picture intensity of screen (Min).
Therefore, under above situation, can only find the solution a screen maximum picture intensity (Max), can utilize maximum picture intensity (Max) and average picture intensity (APL) suitably to find the solution high brightness slope (UPPER) then.
In addition, for example, can high brightness slope (UPPER) be set under the situation of fixed value, can omit finding the solution a screen maximum picture intensity (Max) by the test in advance of display device shown in Figure 4 200.
Therefore, under above situation, only find the solution a screen minimum picture intensity (Min), suitably find the solution basic brightness BY (BASE_Y) based on minimum picture intensity (Min) then.
Like this, be set under the situation of fixed value, can find the solution screen minimum picture intensity (Min) or a screen maximum picture intensity (Max) so that determine not to be set to another parameter of fixed value at high brightness slope (UPPER) or basic brightness BY (BASE_Y).
In the previous embodiment of describing referring to figs. 1 to Fig. 3, the LCD that installs in the LCD panel 109 is corresponding to liquid crystal display cells, and the function of back lighting device is to realize by the white LEDs and the led driver that are installed in the LCD panel 109.
In addition, brightness calculation circuit 105 has been realized the function of mean flow rate calculation element, and PWMGAIN counting circuit 107 has been realized the regulated value calculation element.PWM generative circuit 108 has realized that drive signal forms the function of device.
In addition, brightness calculation circuit 105 has also been realized the function of monochrome information pick-up unit, and image calibrating circuit 104 has been realized the function of image correction apparatus.
Simultaneously, in the aforementioned variant of describing with reference to figure 4, the LCD that installs in the LCD panel 209 is corresponding to liquid crystal display cells, and the function of back lighting device is to realize by the white LEDs and the led driver that are installed in the LCD panel 209.
In addition, brightness calculation circuit 205 has been realized the function of mean flow rate calculation element, realized that mean flow rate is averaged the function of device and luminance parameter interframe is averaged circuit 210, and PWMGAIN counting circuit 207 has been realized the regulated value calculation element.PWM generative circuit 208 has realized that drive signal forms the function of device.
In addition, brightness calculation circuit 205 has also been realized the function of monochrome information pick-up unit, realized that monochrome information is averaged the function of device and luminance parameter interframe is averaged circuit 210, and image calibrating circuit 204 has been realized the function of image correction apparatus.
(application of display control method)
Display device 100 and 200 according to previous embodiment has been employed display control method according to another embodiment of the present invention.In other words, the circuit in the display device 100 shown in Figure 1 is carried out following treatment step respectively:
(1) brightness calculation circuit 105 is carried out the mean flow rate calculation procedure, wherein, the picture signal that show is calculated a screen average picture intensity (that is mean flow rate).
(2) PWMGAIN counting circuit 107 is carried out the regulated value calculation procedure, wherein, based on an average picture intensity of screen and a predetermined linear luminance adjustment curve that in the mean flow rate calculation procedure, calculates, calculate the regulated value of the intensity (that is brightness) of the back lighting device that is used for the regulator solution crystal display element.
(3) PWM generative circuit 108 is carried out drive signals and is formed steps, wherein, calculates based on the regulated value that calculates in the regulated value calculation procedure and to be used to make the pwm signal (that is drive signal) of backlight luminescence of LCD panel 109.The LED that the pwm signal that calculates is provided for LCD panel 109 subsequently drives.
(4) brightness calculation circuit 105 is carried out monochrome information and is detected step, wherein, and for the picture signal that will show detects a minimum picture intensity of screen and a maximum picture intensity (that is, minimum and high-high brightness).
(5) image calibrating circuit 104 carries out image aligning steps, wherein, based on the regulated value that in the regulated value calculation procedure, calculates, the mean flow rate that in the mean flow rate calculation procedure, calculates, detect detected minimum brightness and high-high brightness and predetermined linear image gamma correction curve in the step, come picture signal to be processed carried out and strengthen control in monochrome information.Picture signal through overcorrect is provided for liquid crystal display cells subsequently.
The display control method of carrying out above treatment step (1) to (5) is equivalent to first display control method according to an embodiment of the invention.
Simultaneously, the circuit in the display device 200 shown in Figure 4 is carried out following treatment step respectively.
(A) brightness calculation circuit 205 is carried out the mean flow rate calculation procedure, wherein, the picture signal that show is calculated a screen average picture intensity (that is mean flow rate).
(B) luminance parameter interframe is averaged circuit 210 execution mean flow rates and is averaged step, wherein, on a plurality of frames the average picture intensity of a screen that calculates in the mean flow rate calculation procedure is being averaged.
(C) PWMGAIN counting circuit 207 is carried out the regulated value calculation procedure, wherein, based on mean value that is averaged the average picture intensity of calculating in the step in mean flow rate and predetermined linear luminance adjustment curve, calculate the regulated value of the intensity (that is brightness) of the back lighting device that is used for the regulator solution crystal display element.
(D) PWM generative circuit 208 is carried out drive signals and is formed steps, wherein, calculates based on the regulated value that calculates in the regulated value calculation procedure and to be used to make the pwm signal (that is drive signal) of backlight luminescence of LCD panel 209.The LED that the pwm signal that calculates is provided for LCD panel 209 subsequently drives.
(E) brightness calculation circuit 205 is carried out monochrome information and is detected step, wherein, and for the picture signal that will show detects a minimum picture intensity of screen and a maximum picture intensity (that is, minimum and high-high brightness).
(F) luminance parameter interframe is averaged circuit 210 execution monochrome informations and is averaged step, wherein, respectively detected minimum brightness and high-high brightness in monochrome information detection step is being averaged on a plurality of frames.
(G) image calibrating circuit 204 carries out image aligning steps, wherein, based on the regulated value that in the regulated value calculation procedure, calculates, mean flow rate be averaged the mean flow rate that calculates in the step mean value, be averaged the value and the predetermined linear image gamma correction curve of the value of the minimum brightness that on a plurality of frames, is averaged respectively in the step and high-high brightness in monochrome information, come picture signal to be processed carried out and strengthen control.Be provided for the LCD of LCD panel 209 subsequently through the picture signal of overcorrect.
The display control method of carrying out above treatment step (A) to (G) is equivalent to second display control method according to an embodiment of the invention.
(realization of display control program)
Display control program according to the embodiment of the invention can also be applied to the display device 200 of previous embodiment.In other words, in display device shown in Figure 4 200, image calibrating circuit 204, brightness calculation circuit 205, parameter configuration register circuit 206, PWMGAIN counting circuit 207 and luminance parameter interframe are averaged circuit 210 function separately and can utilize CPU 220 performed programs to realize.
More specifically, the performed respective handling of the circuit of display device 200 can utilize the program of CPU 220 execution to be achieved as follows.This program can be configured to make that the CPU 220 of display device 200 carries out the computer-readable program of following steps:
By the mean flow rate calculation procedure (A) that brightness calculation circuit 205 is carried out, wherein, the picture signal that show is calculated a screen average picture intensity (that is mean flow rate);
The mean flow rate that is averaged circuit 210 execution by luminance parameter interframe is averaged step (B), wherein, on a plurality of frames the average picture intensity of a screen that calculates in the mean flow rate calculation procedure is being averaged;
Regulated value calculation procedure (C) by 207 execution of PWMGAIN counting circuit, wherein, based on mean value that is averaged the average picture intensity of calculating in the step in mean flow rate and predetermined linear luminance adjustment curve, calculate be used to regulate LCD panel 209 intensity backlight (promptly, brightness) regulated value, the regulated value that calculates then is provided to drive signal and forms device, and this drive signal forms device and is used to form and makes the drive signal of backlight luminescence;
The monochrome information of being carried out by brightness calculation circuit 205 detects step (E), wherein, and for the picture signal that will show detects a minimum picture intensity of screen and a maximum picture intensity (that is, minimum and high-high brightness);
The monochrome information that is averaged circuit 210 execution by luminance parameter interframe is averaged step (F), wherein, respectively detected minimum brightness and high-high brightness in monochrome information detection step is being averaged on a plurality of frames; And
Image rectification step (G) by image calibrating circuit 204 execution, wherein, based on the regulated value that in the regulated value calculation procedure, calculates, mean flow rate be averaged the mean flow rate that calculates in the step mean value, be averaged the value and the predetermined linear image gamma correction curve of the value of the minimum brightness that on a plurality of frames, is averaged respectively in the step and high-high brightness in monochrome information, come picture signal to be processed is carried out enhancing control, be provided for the LCD of LCD panel 209 then through the picture signal of overcorrect subsequently.
The program here can be stored in the storer such as ROM (ROM (read-only memory)) in the display device 200 (not illustrating among the figure), and wherein program is to store in the mode that CPU 220 can carry out.Program also can provide via various recording mediums, perhaps via the distribution of of the network phone calls such as the Internet.
In addition, under the situation of display device shown in Figure 1 100, image calibrating circuit 104, brightness calculation circuit 105, parameter configuration register circuit 106 and PWMGAIN counting circuit 107 are set at after the LCDCTL 103.Therefore, if attempt utilizing program to realize foregoing circuit, then be used for then becoming difficult with the control of LCDCTL 103 coordinated manipulations.
But,, also can utilize program to realize image calibrating circuit 104, brightness calculation circuit 105, parameter configuration register circuit 106 and PWMGAIN counting circuit 107 function separately by suitably controlling LCDCTL 103 and CPU 120.
In above program, do not comprise the function of PWM generative circuit 108 and 208.But the present invention is not limited to this program.If the processing power of CPU is higher, then PWM generative circuit 108 and 208 function also can utilize program to realize.Can certainly use a plurality of CPU this processing that distributes.
(other)
More than by example the situation that embodiments of the invention are applied to the display device of installing in the mobile phone handsets has been described.But the present invention is not limited to this configuration.Except mobile phone handsets, embodiments of the invention also can be applied to the display device of installing in the multiple portable electric appts such as personal portable hand-held set or electronic address book (being called as PDA (personal digital assistant)) or laptop computer.
More specifically, in recent years, providing the one section reception service that is suitable for mobile phone and other mobile devices (one segment reception service often is called 1seg broadcasting).Be applied to receive and to be utilized as by this mobile phone or similarly portable set receive and during the portable set of the terrestrial digital television broadcasting of design, the present invention is desirable.
In addition, in the display device that embodiments of the invention certainly are used for installing in the electronic equipment of family or similar position installation and use.
The present invention comprises Japan that Japan of submitting to Jap.P. office with on May 19th, 2008 formerly submits to Jap.P. office in patented claim JP 2008-130437 and on August 11st, 2008 relevant theme of patented claim JP 2008-206683 formerly, by reference its full content is incorporated into here.
It will be understood by those of skill in the art that and depend on designing requirement and other factors, can carry out various modifications, combination, sub-portfolio and change, as long as they are within the scope of claims or its equivalent.

Claims (13)

1. display device comprises:
Liquid crystal display cells;
The back lighting device that is used for described liquid crystal display cells;
The mean flow rate calculation element is used to calculate a screen mean flow rate of the represented image of the picture signal that is used to show;
The regulated value calculation element is used for based on screen the average image brightness and the predetermined linear luminance adjustment curve from described mean flow rate calculation element, calculates the regulated value of the brightness that is used for regulating described back lighting device;
Drive signal forms device, is used for forming based on the regulated value that is calculated by described regulated value calculation element being used for making the drive signal that described back lighting device is luminous, then resulting drive signal is offered described back lighting device;
The monochrome information pick-up unit is used to detect one of the represented screen minimum image brightness of the described picture signal that is used to show and a screen maximum image brightness or both; And
Image correction apparatus, be used for the mean flow rate that calculates based on the regulated value that calculates by described regulated value calculation element, described mean flow rate calculation element and one of the detected minimum brightness of described monochrome information pick-up unit and high-high brightness or linear image gamma correction curve that both are specified, come the described picture signal that is used to show is carried out enhancing control, will offer described liquid crystal display cells through the picture signal of overcorrect then.
2. display device comprises:
Liquid crystal display cells;
The back lighting device that is used for described liquid crystal display cells;
The mean flow rate calculation element is used to calculate a screen mean flow rate of the represented image of the picture signal that is used to show;
Mean flow rate is averaged device, is used to calculate the mean value of a screen mean flow rate on multi-screen from described mean flow rate calculation element;
The regulated value calculation element is used for based on the mean value of the mean flow rate that is averaged device from described mean flow rate and predetermined linear luminance adjustment curve, calculates the regulated value of the brightness be used for regulating described back lighting device;
Drive signal forms device, is used for forming based on the regulated value that is calculated by described regulated value calculation element being used for making the drive signal that described back lighting device is luminous, then resulting drive signal is offered described back lighting device;
The monochrome information pick-up unit is used to detect one of the represented screen minimum image brightness of the described picture signal that is used to show and a screen maximum image brightness or both;
Monochrome information is averaged device, is used to calculate by the detected minimum brightness of described monochrome information pick-up unit at the mean value on the multi-screen and by one of the detected high-high brightness of described monochrome information pick-up unit mean value on multi-screen or both; And
Image correction apparatus, be used for being averaged the mean value of the mean flow rate that device calculates and described monochrome information and be averaged one of average minimum brightness on the multi-screen that device calculates and the average high-high brightness on the multi-screen or both specified linear image gamma correction curves based on the regulated value that calculates by described regulated value calculation element, described mean flow rate, come the described picture signal that is used to show is carried out enhancing control, will offer described liquid crystal display cells through the picture signal of overcorrect then.
3. display device as claimed in claim 1 or 2, wherein, the employed linear luminance adjustment curve of described regulated value calculation element is based on a plurality of linear luminance adjustment curve slopes of each subset definition in the territory of the average brightness value that the minimum value of backlight illumination regulated value and maximal value, one or more threshold values of mean flow rate and these one or more mean flow rate threshold values of serving as reasons divide, and comes appointment.
4. display device as claimed in claim 1 or 2, wherein, the employed linear luminance adjustment curve of described regulated value calculation element is based on a plurality of linear luminance adjustment curve slopes of each definition that three sons in the territory of the average brightness value of dividing than second threshold value on the upper side in the territory of the first threshold on the downside, average brightness value and serve as reasons this first threshold and second threshold value in territory of the minimum value of backlight illumination regulated value and maximal value, average brightness value concentrate, and comes appointment.
5. display device as claimed in claim 4, wherein
Be present in the slope of linear luminance adjustment curve described in the zone between described first threshold and described second threshold value and the ratio that is varied to of mean flow rate in mean flow rate, and
Be less than or equal to the variation of mean flow rate with the slope of linear luminance adjustment curve described in the zone that is higher than described second threshold value in the zone that is lower than described first threshold.
6. display device as claimed in claim 1 or 2, wherein, the employed linear image gamma correction of described image correction apparatus curve be based on the low subclass of brightness value in the processed picture signal first slope, the brightness value in the processed picture signal higher subclass second slope, be defined under the situation of zero luminance of processed picture signal through the basic brightness value of the minimum brightness value of the picture signal of overcorrect and the flex point that indicates the brightness value at slope variation place, come appointment.
7. display device as claimed in claim 6, wherein
The ratio that is varied to of the brightness of described first slope and processed picture signal, and
The value of described second slope is less than or equal to 1.
8. display control method may further comprise the steps:
One screen mean flow rate of the image that the picture signal that calculating is used to show is represented;
Screen the average image brightness and a predetermined linear luminance adjustment curve based on calculating in the mean flow rate calculation procedure calculates the regulated value of the brightness that is used for regulating the back lighting device that is used for liquid crystal display cells;
Be used for making the drive signal that described back lighting device is luminous based on forming, then resulting drive signal offered described back lighting device by the regulated value that in the regulated value calculation procedure, calculates;
Detect one of the represented screen minimum image brightness of the described picture signal that is used to show and a screen maximum image brightness or both; And
Based on detecting one of detected minimum brightness and high-high brightness or both specified linear image gamma correction curves in the step by the regulated value that in the regulated value calculation procedure, calculates, the mean flow rate that in the mean flow rate calculation procedure, calculates and in monochrome information, come the described picture signal that is used to show is carried out enhancing control, will offer described liquid crystal display cells through the picture signal of overcorrect then.
9. display control method may further comprise the steps:
One screen mean flow rate of the image that the picture signal that calculating is used to show is represented;
On the multi-screen screen mean flow rate that calculates in the mean flow rate calculation procedure is being averaged;
Based on mean value that is averaged the mean flow rate that calculates in the step in mean flow rate and predetermined linear luminance adjustment curve, calculate the regulated value of the brightness that is used for regulating the back lighting device that is used for liquid crystal display cells;
Form based on the regulated value that in the regulated value calculation procedure, calculates and to be used for making the drive signal that described back lighting device is luminous, then resulting drive signal is offered described back lighting device;
Detect one of the represented screen minimum image brightness of the described picture signal that is used to show and a screen maximum image brightness or both; And
Respectively one of detected minimum brightness and high-high brightness in monochrome information detection step or both are being averaged on the multi-screen; And
Based on by the regulated value that in the regulated value calculation procedure, calculates, be averaged the mean value of the mean flow rate that calculates in the step and be averaged one of average minimum brightness on the multi-screen that calculates in the step and the average high-high brightness on the multi-screen or both specified linear image gamma correction curves in monochrome information in mean flow rate, come the described picture signal that is used to show is carried out enhancing control, will offer described liquid crystal display cells through the picture signal of overcorrect then.
10. one kind makes the computing machine of installing in the display device carry out the computer-readable display control program of following steps:
One screen mean flow rate of the image that the picture signal that calculating is used to show is represented;
Based on a screen the average image brightness and a predetermined linear luminance adjustment curve that in the mean flow rate calculation procedure, calculates, calculating is used for regulating the regulated value of the brightness of the back lighting device that is used for liquid crystal display cells, described regulated value is offered to be used to form the drive signal formation device that makes the luminous drive signal of described back lighting device then;
Detect one of the represented screen minimum image brightness of the described picture signal that is used to show and a screen maximum image brightness or both; And
Based on detecting one of detected minimum brightness and high-high brightness or both specified linear image gamma correction curves in the step by the regulated value that in the regulated value calculation procedure, calculates, the mean flow rate that in the mean flow rate calculation procedure, calculates and in monochrome information, come the described picture signal that is used to show is carried out enhancing control, will offer described liquid crystal display cells through the picture signal of overcorrect then.
11. one kind makes the computing machine of installing in the display device carry out the computer-readable display control program of following steps:
One screen mean flow rate of the image that the picture signal that calculating is used to show is represented;
On the multi-screen screen mean flow rate that calculates in the mean flow rate calculation procedure is being averaged;
Based on mean value that is averaged the mean flow rate that calculates in the step in mean flow rate and predetermined linear luminance adjustment curve, calculating is used for regulating the regulated value of the brightness of the back lighting device that is used for liquid crystal display cells, described regulated value is offered to be used to form the drive signal formation device that makes the luminous drive signal of described back lighting device then;
Detect one of the represented screen minimum image brightness of the described picture signal that is used to show and a screen maximum image brightness or both;
Respectively one of detected minimum brightness and high-high brightness in monochrome information detection step or both are being averaged on the multi-screen; And
Based on by the regulated value that in the regulated value calculation procedure, calculates, be averaged the mean value of the mean flow rate that calculates in the step and be averaged one of average minimum brightness on the multi-screen that calculates in the step and the average high-high brightness on the multi-screen or both specified linear image gamma correction curves in monochrome information in mean flow rate, come the described picture signal that is used to show is carried out enhancing control, will offer described liquid crystal display cells through the picture signal of overcorrect then.
12. a display device comprises:
Liquid crystal display cells;
Be used for the backlight of described liquid crystal display cells;
The mean flow rate counting circuit is configured to calculate a screen mean flow rate of the represented image of the picture signal that is used to show;
The regulated value counting circuit is configured to based on screen the average image brightness and the predetermined linear luminance adjustment curve from described mean flow rate counting circuit, calculates the regulated value that is used for regulating described brightness backlight;
Drive signal generation circuit is configured to form based on the regulated value that is calculated by described regulated value counting circuit and is used for making and then resulting drive signal is offered the drive signal of described backlight luminescence described backlight;
The monochrome information testing circuit is configured to detect one of the represented screen minimum image brightness of the described picture signal that is used to show and a screen maximum image brightness or both; And
Image calibrating circuit, be configured to the mean flow rate that calculates based on the regulated value that calculates by described regulated value counting circuit, described mean flow rate counting circuit and one of the detected minimum brightness of described monochrome information testing circuit and high-high brightness or linear image gamma correction curve that both are specified, come the described picture signal that is used to show is carried out enhancing control, will offer described liquid crystal display cells through the picture signal of overcorrect then.
13. a display device comprises:
Liquid crystal display cells;
Be used for the backlight of described liquid crystal display cells;
The mean flow rate counting circuit is configured to calculate a screen mean flow rate of the represented image of the picture signal that is used to show;
Mean flow rate is averaged circuit, is configured to calculate the mean value of a screen mean flow rate on multi-screen from described mean flow rate counting circuit;
The regulated value counting circuit is configured to based on the mean value of the mean flow rate that is averaged circuit from described mean flow rate and predetermined linear luminance adjustment curve, calculates the regulated value be used for regulating described brightness backlight;
Drive signal generation circuit is configured to form based on the regulated value that is calculated by described regulated value counting circuit and is used for making and then resulting drive signal is offered the drive signal of described backlight luminescence described backlight;
The monochrome information testing circuit is configured to detect one of the represented screen minimum image brightness of the described picture signal that is used to show and a screen maximum image brightness or both;
Monochrome information is averaged circuit, is configured to calculate by the detected minimum brightness of described monochrome information testing circuit at the mean value on the multi-screen and by the mean value of the detected high-high brightness of described monochrome information testing circuit on multi-screen; And
Image calibrating circuit, be configured to be averaged the mean value of the mean flow rate that circuit calculates and described monochrome information and be averaged one of average minimum brightness on the multi-screen that circuit calculates and the average high-high brightness on the multi-screen or both specified linear image gamma correction curves based on the regulated value that calculates by described regulated value counting circuit, described mean flow rate, come the described picture signal that is used to show is carried out enhancing control, will offer described liquid crystal display cells through the picture signal of overcorrect then.
CNA2009101429668A 2008-05-19 2009-05-19 Display apparatus, display control method, and display control program Pending CN101587698A (en)

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CN102347014A (en) * 2011-10-25 2012-02-08 中兴通讯股份有限公司 Method and device for adjusting backlight brightness of display panel
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CN101877208A (en) * 2010-06-29 2010-11-03 彩虹集团公司 Control method of LED backlight
CN101877208B (en) * 2010-06-29 2013-07-03 彩虹集团公司 Control method of LED backlight
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CN102347014B (en) * 2011-10-25 2016-09-14 中兴通讯股份有限公司 A kind of method and device of adjusting backlight brightness of display panel
CN102347014A (en) * 2011-10-25 2012-02-08 中兴通讯股份有限公司 Method and device for adjusting backlight brightness of display panel
CN102750912B (en) * 2012-07-13 2015-04-08 冠捷显示科技（厦门）有限公司 LED backlight dynamic control device and control method thereof
CN102750912A (en) * 2012-07-13 2012-10-24 冠捷显示科技（厦门）有限公司 LED backlight dynamic control device and control method thereof
CN103021335B (en) * 2012-12-14 2015-01-07 京东方科技集团股份有限公司 OLED (organic light emitting diode) driving circuit, OLED display device and brightness adjusting method for OLED display device
CN103021335A (en) * 2012-12-14 2013-04-03 京东方科技集团股份有限公司 OLED (organic light emitting diode) driving circuit, OLED display device and brightness adjusting method for OLED display device
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