CN101393725A - Liquid crystal display device, image brightness controlling circuit and method - Google Patents
Liquid crystal display device, image brightness controlling circuit and method Download PDFInfo
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Abstract
The invention discloses an image brightness control circuit, which comprises a receiving unit, a processing unit and a control unit, wherein the receiving unit is used for receiving the image brightness signals; the processing unit is used for determining the brightness level of the brightness signals received by the receiving unit, and generating and outputting the image brightness control signals and the backlight brightness control signals according to the determining results; and the control unit is used for controlling the image brightness through the image brightness control signals output by the processing unit, and controlling the backlight brightness through the backlight brightness control signals, so that the brightness of the displayed image signals can meet the requirements for the brightness level determined by the processing unit. The invention further discloses a method for controlling the image brightness and an LCD. The invention has the advantages that the power consumption of the backlight is reduced, and the power energy is further reduced.
Description
Technical field
The present invention relates to image processing techniques, relate in particular to a kind of LCD, image brightness controlling circuit and method.
Background technology
Characteristics such as that LCD has is frivolous, low power consumption and radiation are few, therefore be widely used on the equipment such as monitor, digital television, mobile phone and portable computer, because liquid crystal itself is not luminous, therefore LCD need be come luminous by luminophor, usually backlight is set as light source in LCD inside, liquid crystal places the front of backlight and realizes the demonstration of LCD to image as a kind of light medium of preaching.At present, in the process of liquid crystal display displays image, backlight remains to be lighted and brightness generally remains unchanged, and produces a large amount of power attenuations, consumes a large amount of power supply energies.
Summary of the invention
Embodiment of the invention technical matters to be solved is, a kind of LCD, image brightness controlling circuit and method are provided.Can in the process of liquid crystal display displays image, reduce the power attenuation of backlight, and then reduce power supply energy.
In order to solve the problems of the technologies described above, the embodiment of the invention provides a kind of intednsity circuit, comprising:
Receiving element is used to receive image brightness signal;
Processing unit, the brightness degree of the luminance signal that is used to judge that described receiving element receives, and generate and output image brightness control signal and brightness of backlight control signal according to described result of determination;
Control module, be used for by the described brightness of image control signal control chart image brightness of described processing unit output and by described brightness of backlight control signal control brightness of backlight, so that the requirement of the determined brightness degree of described processing unit is satisfied in the brightness of the picture signal that shows.
Accordingly, the embodiment of the invention also provides a kind of LCD, comprise backlight, backlight power circuit and the liquid crystal panel that is positioned at described backlight the place ahead, it is characterized in that, this LCD also comprises an image brightness controlling circuit, link to each other with described liquid crystal panel with described backlight power circuit respectively, described image brightness controlling circuit comprises:
Receiving element is used to receive image brightness signal;
Processing unit, the brightness degree of the luminance signal that is used to judge that described receiving element receives, and according to described result of determination output image brightness control signal and brightness of backlight control signal;
Control module, be used for by the described brightness of image control signal control chart image brightness of described processing unit output and by described brightness of backlight control signal control brightness of backlight, so that the requirement of the determined brightness degree of described processing unit is satisfied in the brightness of the picture signal that shows.
Accordingly, the embodiment of the invention also provides a kind of image brightness control method, comprising:
Receive image brightness signal;
Judge the brightness degree of received image brightness signal, and generate and output image brightness control signal and brightness of backlight control signal according to described brightness degree;
By the described brightness of image control signal control chart image brightness of described processing unit output and by described brightness of backlight control signal control brightness of backlight, so that the requirement of described definite brightness degree is satisfied in the brightness of the picture signal of demonstration.
The embodiment of the invention is in image display process, and the brightness of backlight is followed the variation of brightness of image and changed, greatly reduce in the image display process, and the power attenuation of backlight, and then reduced power supply energy.
Description of drawings
Fig. 1 is that an example structure of LCD of the present invention is formed synoptic diagram;
Fig. 2 is that first example structure of image brightness controlling circuit among Fig. 1 of the present invention is formed synoptic diagram;
Fig. 3-Fig. 6 is that the brightness of image of embodiment shown in Fig. 2 and an embodiment between brightness of image control signal and brightness of backlight control signal concern synoptic diagram;
Fig. 7 is the first embodiment schematic flow sheet of image brightness control method of the present invention;
Fig. 8 is that second example structure of image brightness controlling circuit among Fig. 1 of the present invention is formed synoptic diagram;
Fig. 9 is the second embodiment schematic flow sheet of image brightness control method of the present invention.
Embodiment
For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with drawings and Examples.
Fig. 1 is that an example structure of LCD of the present invention is formed synoptic diagram.As shown in Figure 1, the LCD of present embodiment comprises backlight 1, backlight power circuit 2, liquid crystal panel 3 and image brightness controlling circuit 4, and wherein, described backlight 1 is used to this LCD that light source is provided; Described backlight power circuit 2 is used to described backlight 1 that power supply is provided; Backlight commonly used at present comprises cold-cathode fluorescence lamp (CCFL, Cold-cathode Fluorescent Lamp) and light emitting diode (LED, Light EmittingDiode).Described liquid crystal panel 3 is used to do light conductive medium, display image signals; Described brightness of image control signal circuit 4 links to each other with described liquid crystal panel 3 with described backlight power circuit 2 respectively, be used to judge the brightness degree of the image brightness signal that receives, generate brightness of image control signal and brightness of backlight control signal according to described result of determination, and the described brightness of image control signal control chart image brightness by described generation and by described brightness of backlight control signal control brightness of backlight, so that the requirement of described definite brightness degree is satisfied in the brightness of the picture signal that shows.
Fig. 2 is that an example structure of image brightness controlling circuit 4 is formed synoptic diagram among Fig. 1.As shown in Figure 2, the image brightness controlling circuit 4 of present embodiment comprises receiving element 41, processing unit 42 and control module 43, and wherein, described receiving element 41 is used to receive image brightness signal; In the specific implementation, picture signal can delegation, delegation, and therefore He Yichang,, an or frame, a frame transmit is carrying out when image shows, also can be by delegation, delegation, and He Yichang,, or a frame, a frame scan to receive and show.The brightness degree of the luminance signal that described processing unit 42 is used to judge that described receiving element 41 receives, and generate and output image brightness control signal and brightness of backlight control signal according to described result of determination; The described brightness of image control signal control chart image brightness that described control module 43 generates by described processing unit 42 and by described brightness of backlight control signal control brightness of backlight is so that the requirement of described definite brightness degree is satisfied in the brightness of the picture signal of demonstration.
Further with reference to figure 2, described processing unit 42 comprises peak detection unit 421, first storage unit 422, determining unit 423 and generation unit 424, wherein,
Described peak detection unit 421 is used to detect the peak value of the luminance signal that described receiving element 41 receives; General diode or triode adds the function that electric capacity can realize that promptly peak value detects.In the luminance signal effective period of the capacitor discharge time correspondence of the peak detection unit of present embodiment (frame, or one, or delegation).If the amplitude of a back signal is higher than the amplitude of previous signal, so, a back signal is when being carried out amplitude detection, and filter capacitor can continue charging on the basis of previous signal charging, and makes the amplitude of charging continue to raise; If the amplitude of a back signal is lower than the amplitude of previous signal, a so back signal is when being carried out amplitude detection, filter capacitor can not continue charging again on the basis of previous signal charging, but can not discharge yet, but keeps original maximum voltage value; When arriving, filter capacitor just discharges up to next effective period (frame, or, or delegation), to guarantee the real-time of peak detection circuit work.Peak detection unit also can adopt digital circuit technique to realize, an A/D converter at first will be arranged, by sampling analog signal conversion is become digital signal, the digital signal that sampling is obtained is stored then, the every storage of signal is once just carried out data processing once, promptly by two data are compared, preserving corresponding to the bigger numerical value of luminance signal amplitude, relatively use for proceed next time, (frame in the effective cycle of luminance signal then, or one, or delegation) maximal value is elected.
Described first storage unit 422 is used for the brightness degree criterion of memory image luminance signal; Such as, example 1, brightness of image can be divided into 1 grade, 2 grades, 3 grades ... 7 grades, 8 grades, 10 grades such as 9 grades and 10 grades, the corresponding corresponding luminance voltage of each grade, regulation shows that brightness of image is 1 grade of brightness during smaller or equal to 1 volt when luminance voltage, when luminance voltage greater than 1 volt, show during smaller or equal to 2 volts that brightness of image is 2 grades of brightness, when luminance voltage greater than 2 volts, show during smaller or equal to 3 volts that brightness of image is 3 grades of brightness, when luminance voltage greater than 6 volts, show during smaller or equal to 7 volts that brightness of image is 7 grades of brightness, when luminance voltage greater than 7 volts, show during smaller or equal to 8 volts that brightness of image is 8 grades of brightness, when luminance voltage greater than 8 volts, show during smaller or equal to 9 volts that brightness of image is 9 grades of brightness, when luminance voltage greater than 9 volts, show during smaller or equal to 10 volts that brightness of image is 10 grades of brightness.For another example, example 2: set a benchmark magnitude of voltage, when the ratio of luminance voltage value and described reference voltage value shows that brightness of image is 1 grade of brightness smaller or equal to 10% the time, when the ratio of luminance voltage value and described reference voltage value greater than 10%, show that smaller or equal to 20% o'clock brightness of image is 2 grades of brightness ... when the ratio of luminance voltage value and described reference voltage value greater than 80%, show that smaller or equal to 90% o'clock brightness of image is 9 grades of brightness, when the ratio of luminance voltage value and described reference voltage value greater than 90%, show that smaller or equal to 100% o'clock brightness of image is 10 grades of brightness.First storage unit 422 can be RAM or ROM storer
Described determining unit 423 is used for described criterion and the described peak detection unit 421 detected described peak values according to 422 storages of described first storage unit, determines the brightness degree of the luminance signal that described receiving element 41 receives; Be right after above-mentioned example 1, determining unit 423 comprises comparer and requestor, the size of the boundary values of more described peak detection unit 421 detected crest voltage of comparer and described first storage unit, 422 stored voltage rate ranges is to determine the scope of described peak detection unit 421 detected peak values; Requestor is inquired about the classification standard of described first storage unit 422, determines the grade of described peak value scope correspondence of living in, with the grade of the luminance signal of determining described peak detection unit 421 detected peak value correspondences.Such as, when peak value is 5.5 volts,,, determine that then the luminance signal of this peak value correspondence is 6 grades of brightness less than 6 volts by relatively finding this voltage greater than 5 volts.For another example, be right after above-mentioned example 2, determining unit 423 comprises divider and requestor, and this divider is done division to draw number percent with the reference voltage of described peak detection unit 421 detected crest voltage and 422 storages of described first storage unit; Requestor is inquired about the classification standard of described first storage unit 422, determines the grade of described number percent correspondence, with the grade of the luminance signal of determining described peak detection unit 421 detected peak value correspondences.Such as, peak value is 8.4 volts, and reference voltage is 10 volts, and the ratio that draws the two by divider is 84%, inquires about this ratio greater than 80% by requestor, less than 90%, determines that then the luminance signal of this peak value correspondence is 9 grades of brightness.In addition, determining unit 423 also can have the function to other unit co-ordination simultaneously concurrently, such as, when effectively the work period finishes, the data in the peak detection unit 421 are carried out clearly 0, or discharge on the filter capacitor charge stored (electric capacity both end voltage) etc.
Further with reference to figure 2, described control module 43 comprises brightness of image control module 431 and brightness of backlight control module 432, wherein,
Described brightness of image control module 431 is used for the described brightness of image control signal control chart image brightness according to described generation unit 424 outputs.
Described brightness of backlight control module 432 is used for the described brightness of backlight control signal control brightness of backlight according to described generation unit 424 outputs.
Concern synoptic diagram with reference to the brightness of image of the figure 3-embodiment of the invention shown in Figure 6 and an embodiment between brightness of image control signal and brightness of backlight control signal; As Fig. 3-shown in Figure 6, the influence that the brightness of image of the embodiment of the invention is changed by brightness of image control signal L1 not only will, the influence that changed by brightness of backlight control signal L2.Brightness of image control signal L1 is shown Fig. 3 and brightness of backlight control signal L2 changes preceding brightness of image curve, Fig. 4 shows brightness of image control signal L1 and changes influence to brightness of image, and Fig. 5 shows brightness curve L2 when backlight by the influence that changes brightness of image.Fig. 6 shows brightness of image control signal L1 and brightness of backlight control signal L2 and changes influence to brightness of image simultaneously.Among Fig. 3-Fig. 6, the brightness of y presentation video, t express time.With reference to figure 3 and Fig. 4, when with brightness of image control signal L1 when C1 heightens C2, whole piece brightness of image curve all will upwards move, i.e. the whole rising of brightness of image (if C1 turns down, whole piece brightness of image curve will descend, i.e. the whole step-down of brightness of image).With reference to figure 3 and Fig. 5, when with backlight lamp control signal L2 when Z1 drops to Z2, whole piece brightness of image curve all will be to decline, i.e. the whole reduction of brightness of image (as shown in the figure, L2 moves and causes the brightness of image distortion).As Fig. 3 and shown in Figure 6, when with backlight lamp control signal L2 when Z1 drops to Z3, simultaneously the brightness of image control signal is elevated to C3 from C1, the brightness of image curve is remained unchanged, the brightness of image distortion just can be corrected fully, and in whole process, brightness of backlight has dropped to Z2 from Z1, and the backlight power attenuation has reduced.Should be noted that some brightness of backlight control curve will be higher than the peak of brightness of image curve all the time, can distortion can guarantee brightness of image.
We can further illustrate.If picture carrier is divided into 10 grades, the 1st grade of brightness is minimum, and the 10th grade of brightness is the highest, and is divided into 10 (or frame) picture signals respectively and shows, is designated as respectively: V1, V2, V3, V4, V5, V6, V7, V8, V9, V10.Corresponding brightness control signal also has 10 grades, is designated as respectively: C1, C2, C3, C4, C5, C6, C7, C8, C9, C10.The brightness of backlight also has 10 grades, is designated as respectively: L1, L2, L3, L4, L5, L6, L7, L8, L9, L10; When the brightness of backlight was non-adjustable, its brightness was in high state, and brightness degree is designated as L10.So, 10 grades of picture carrier can be regarded 10 kinds of different conditions that 2 kinds of different elements carry out combination results as, are designated as respectively:
V1＝C1+L10，V2＝C2+L10，V3＝C3+L10，V4＝C4+L10，V5＝C5+L10，V6＝C6+L10，
V7＝C7+L10，V8＝C8+L10，V9＝C9+L10，V10＝C10+L10 (1)
Now, it is adjustable that we make the brightness of backlight be divided into 3 grades, promptly the brightness of backlight is divided into 100%, 70%, 40% Three Estate (being equivalent to L10, L7, L4), and discuss respectively under three kinds of different brightness of backlight situations, the situation of brightness of image and contrast, and the situation of saving backlight power.First kind of brightness of backlight is the situation of 100% (L10), the result who had discussed above promptly.Please referring to (1) formula analysis result.
Below our emphasis analyze the situation that other brightness of backlight is respectively 70%, 40% (L7, L4).(brightness of backlight is divided into L10, L7, a L43 grade here, just illustrates, can at random be divided into a lot of grades in the practical application, and can be adjustable continuously).
When picture carrier is reduced to 7 grades (comprising 7 grades) between 4 grades the time, corresponding brightness of backlight can be reduced to 70% by 100%, and then top 10 kinds of different conditions can be changed into:
U1＝C1+L7，U2＝C2+L7，U3＝C3+L7，U4＝C4+L7，U5＝C5+L7，U6＝C6+L7，
U7＝C7+L7，U8＝C8+L7，U9＝C9+L7，U10＝C10+L7 (2)
Because the brightness of backlight reduces, obviously the brightness of U1, U2, U3, U4, U5, U6, U7, U8, U9, U10 is lower than the brightness of V1, V2, V3, V4, V5, V6, V7, V8, V9, V10 respectively.
But, if we can improve picture carrier (supposing that picture carrier is directly proportional with the amplitude of brightness control signal) by the amplitude that improves brightness control signal, and relational expression: V1=C1+L10=C4+L7 sets up, then the grade of picture carrier can be arranged in order into:
U1、U2、U3、U4、U5、U6、U7、U8、U9、U10、V8、V9、V10 (3)
Or: U1, U2, U3, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10 (4)
According to (3) formula as can be known, if make the amplitude of the brightness of backlight and brightness control signal simultaneously adjustable, when brightness of image is 7 grades, the brightness of corresponding backlight is reduced to 70% o'clock of high-high brightness, picture carrier not only can distortion, the power of backlight can also save 30%, and the contrast of image can also be than 3 grades of original increases: U1, U2, U3 (3 ,-2 ,-1).But, can only adopt a kind of brightness of backlight control model in a field picture luminance signals shows, therefore, 3 grades of brightness of image V8, V9, the V10 of back also needs the brightness of backlight is transferred to 100% in (3) formula.Because we have supposed that with field (or frame) picture signal be the control unit front; Also can with go picture signal serve as control unit.
We continue to discuss the situation that the brightness of backlight is reduced to 40% (L4) again, that is: when picture carrier was reduced to 4 grades, the brightness of backlight also dropped to 40% (L4) by 100% (L10).Then top 10 kinds of different luminance states also can change by changing brightness control signal, are designated as respectively:
u1＝C1+L4，u2＝C2+L4，u3＝C3+L4，u4＝C4+L4，u5＝C5+L4，u6＝C6+L4，
u7＝C7+L4，u8＝C8+L4，u9＝C9+L4，u10＝C10+L4 (5)
Equally, if we improve picture carrier (supposing that picture carrier is directly proportional with the amplitude of brightness control signal) by the amplitude that improves brightness control signal, and relational expression: U1=C1+L7=C4+L4 sets up, and then the grade of picture carrier can be arranged as:
u1、u2、u3、u4、u5、u5、u6、u7、u8、u9、u10、U8、U9、U10、V8、V9、V10 (6)
Or:
u1、u2、u3、U1、U2、U3、V1、V2、V3、V4、V5、V6、V7、V8、V9、V10 (7)
According to (6) formula and (7) formula as can be known, if make the adjustable brightness of backlight, when picture carrier is that 7 grades (comprising 7 grades) are between 4 grades the time, the adjustable brightness of backlight is to 70% (L7) of high-high brightness, picture carrier not only can distortion, and backlight can also save power (30%), and image shows and can also increase contrast; When picture carrier is that 4 grades (comprising 4 grades) are when following, the brightness of backlight can also further reduce, and is reduced to 40% (L4) of high-high brightness, and picture carrier can distortion yet, and backlight can be saved power (60%), and image shows that contrast can increase by 6 grades altogether.
In like manner, owing in a field picture luminance signals shows, can only adopt a kind of brightness of backlight control model, therefore, 6 grades of brightness of image V5, V6, V7 and V8, V9, the V10 of back also needs the brightness of backlight is transferred to 70% and 100% respectively in (7) formula.
Further analyze below, but, can save how many backlight powers when the brightness of backlight timing.
If the adjustable extent of the brightness of backlight is 40%～100%, that is: when television image brightness is the highest, be 100% (when brightness of backlight is turned up full blast), when television image brightness is minimum be 40% (brightness of backlight be transferred to minimum time), then the mean flow rate of television image brightness and backlight all is 70%.Generally speaking, it is that the chance of minimum situation can be not a lot of for brightness appears in the highest or television image that brightness appears in television image, its probability density distribution meets normal distribution (Gaussian distribution) basically, that is: chance to occur when brightness is about 70% maximum for television image.The expression formula of normal distyribution function is:
(8) in the formula, y represents probability density, and x represents brightness, and wherein μ is the average of normal distribution, and σ is the standard deviation of normal distribution.
Suppose that when the brightness of backlight was non-adjustable, its brightness was 100%; When the brightness of backlight be high-high brightness 70% the time, compare with high-high brightness, be equivalent to save power 30% (supposing that brightness is directly proportional with power); But but the brightness of working as backlight is timing, its brightness may change between 70% to 100% back and forth, and from Fig. 3 as can be seen, brightness changes near 70% probability wants the probability of specific luminance close 100% a lot of greatly, if estimate, can save power and be approximately 15% according to curve ratio among the figure.
Same principle, the brightness of backlight high-high brightness 40% to 70% between scope in also can occur; Equally, brightness change near 70% probability than near 40% probability more greatly, that is: can save power equally and be approximately 15%.
If changing near 40% probability that occurs and brightness variation, brightness equates substantially near 100% probability that occurs, so, although the variation range of brightness of backlight is 40% to 100%, but save power and remain 30% of former general power, the mean flow rate that is equivalent to backlight can be reduced to 70%.That is:
P
X＝P
100-P
70＝P
030％ (9)
(9) P in the formula
XBut be the power that the brightness range timing of backlight is saved, P
100The expression brightness of backlight is the power of loss in 100% o'clock, P
70The expression brightness of backlight is the power of loss in 70% o'clock, P
0The power of loss when the expression backlight did not have brightness regulation originally.
In actual applications, backlight generally all is to adopt the Switching Power Supply power supply, it is lighted and closes all needs the regular hour, the frequency of operation of Switching Power Supply is got higherly can reach better effect, and the Switching Power Supply frequency of operation surpasses the very general of 300kHz at present.
Fig. 7 is the first embodiment schematic flow sheet of image brightness control method of the present invention; As shown in the figure, the image brightness control method of present embodiment comprises:
Step S100 receives image brightness signal;
Step S101 detects the peak value of the described luminance signal that receives;
Step S102 according to the brightness degree criterion of the image brightness signal of storing and the peak value of the detected luminance signal of described detecting unit, determines the brightness degree of the described luminance signal that receives; Such as, example 1, brightness of image can be divided into 1 grade, 2 grades, 3 grades ... 7 grades, 8 grades, 10 grades such as 9 grades and 10 grades, the corresponding corresponding luminance voltage of each grade, regulation shows that brightness of image is 1 grade of brightness during smaller or equal to 1 volt when luminance voltage, when luminance voltage greater than 1 volt, show during smaller or equal to 2 volts that brightness of image is 2 grades of brightness, when luminance voltage greater than 2 volts, show during smaller or equal to 3 volts that brightness of image is 3 grades of brightness, when luminance voltage greater than 6 volts, show during smaller or equal to 7 volts that brightness of image is 7 grades of brightness, when luminance voltage greater than 7 volts, show during smaller or equal to 8 volts that brightness of image is 8 grades of brightness, when luminance voltage greater than 8 volts, show during smaller or equal to 9 volts that brightness of image is 9 grades of brightness, when luminance voltage greater than 9 volts, show during smaller or equal to 10 volts that brightness of image is 10 grades of brightness.For another example, example 2: set a benchmark magnitude of voltage, when the ratio of luminance voltage value and described reference voltage value shows that brightness of image is 1 grade of brightness smaller or equal to 10% the time, when the ratio of luminance voltage value and described reference voltage value greater than 10%, show that smaller or equal to 20% o'clock brightness of image is 2 grades of brightness ... when the ratio of luminance voltage value and described reference voltage value greater than 80%, show that smaller or equal to 90% o'clock brightness of image is 9 grades of brightness, when the ratio of luminance voltage value and described reference voltage value greater than 90%, show that smaller or equal to 100% o'clock brightness of image is 10 grades of brightness.Be right after above-mentioned example 1, determine that brightness degree can be through comparing and inquiring about two steps and realize, the boundary values of at first more described detected crest voltage and described stored voltage rate range is to determine the scope of peak value; After the scope of determining peak value, by the classification standard of inquiry storage, determine the grade of described peak value scope correspondence of living in, with the grade of the luminance signal of determining described detected peak value correspondence.Such as, when peak value is 5.5 volts,,, determine that then the luminance signal of this peak value correspondence is 6 grades of brightness less than 6 volts by relatively finding this voltage greater than 5 volts.For another example, be right after above-mentioned example 2, determine that the step of brightness degree can realize through division arithmetic and two steps of inquiry, at first by the reference voltage of detected crest voltage and storage is done division to draw number percent; After obtaining number percent, by the classification standard of inquiry storage, determine the grade of described number percent correspondence, with the grade of the luminance signal of determining described detected peak value correspondence.Such as, peak value is 8.4 volts, and reference voltage is 10 volts, and the ratio that draws the two by divider is 84%, inquires about this ratio greater than 80% by requestor, less than 90%, determines that then the luminance signal of this peak value correspondence is 9 grades of brightness.
Step S103 generates brightness of image control signal and brightness of backlight control signal according to described definite brightness degree;
Step S104, the described brightness of image control signal control chart image brightness by described generation and by described brightness of backlight control signal control brightness of backlight is so that the requirement of described definite brightness degree is satisfied in the brightness of the picture signal that shows.
Fig. 8 is that second example structure of image brightness controlling circuit among Fig. 1 of the present invention is formed synoptic diagram; As shown in Figure 8, the difference of the present embodiment and first embodiment is, the image brightness controlling circuit of present embodiment is Duoed a synchronizing signal processing unit 44 than first embodiment, this synchronizing signal processing unit 44 is used for the synchronizing signal that receives is handled, and export width respectively and meet the field sync signal that the line synchronizing signal of horizontal flyback period of the image brightness signal that described receiving element 41 receives and width meet the field flyback period of the image brightness signal that described receiving element 41 receives and give described brightness of backlight control module 432, so that described brightness of backlight control module 432 control backlights are closed in the line retrace sweep time and the field flyback of picture signal sweep time.
Further described synchronizing signal processing unit 44 comprises synchronous Signal Receiver Unit 441, synchronous signal separation unit 442, line synchronizing signal processing unit 443 and field sync signal processing unit 444, wherein,
Described synchronous Signal Receiver Unit 441 is used to receive synchronizing signal;
The described synchronizing signal that described synchronous signal separation unit 442 is used for described synchronous Signal Receiver Unit is received is separated into line synchronizing signal and field sync signal;
Described line synchronizing signal processing unit 443 is used for the line synchronizing signal of described synchronous signal separation unit 442 outputs is handled, and the output width meets the line synchronizing signal of the horizontal flyback period of the image brightness signal that described receiving element 41 receives;
Field sync signal processing unit 444 is used for the field sync signal of described synchronous signal separation unit 442 outputs is handled, and the output width meets the described field sync signal that receives the field flyback period of single 41 yuan of image brightness signals that receive.
Image can produce trace scanning and retrace scanning when scanning, also claim to scan the blanking time during retrace scanning.Be expert at, the field scan blanking therebetween, image does not show.Can save part of back lamp power like this.
Such as, the line-scanning period is 64 microseconds, and trace sweep time is 51.5 microseconds, and the retrace scanning time is 12.5 microseconds.Brightness of backlight is closed during the scan retrace if be expert at, then can save power and be:
(10) in the formula, P
HBe the power that the line scanning retrace interval is saved, T
OFFBe line scanning retrace interval, T
HBe the line-scanning period, P
0General power for former backlight loss.That is: brightness of backlight is closed during the scan retrace of being expert at, and then can save 20% of former backlight loss general power.
For another example, field-scanning period is 20 milliseconds, and trace sweep time is 16 milliseconds, and the retrace scanning time is 4 milliseconds.If scan retrace scan period handle back of the body brightness of backlight on the scene is closed, then can save power 20% equally.That is:
(11) in the formula, P
VBe the power that the field scan retrace interval is saved, T
OFFBe field scan retrace interval, T
VBe field-scanning period, P
0General power for former backlight loss.
If (10) formula and the savable power of (11) formula are merged, then can save power and be about 36% of former backlight loss general power.That is:
P
HV＝P
0(1-20％)20％+P
020％＝P
036％ (12)
(12) in the formula, P
HVBe the power that row, field scan retrace interval are saved, P
0General power for former backlight loss.
Fig. 9 is an embodiment schematic flow sheet controlling brightness of backlight in the image brightness control method of the present invention by synchronizing signal.As shown in Figure 9, the flow process of passing through synchronizing signal control brightness of backlight of present embodiment comprises:
Step S200 when receiving image brightness signal, receives synchronizing signal;
Step S201 is separated into line synchronizing signal and field sync signal with the synchronizing signal of described reception;
Step S202 handles described isolated line synchronizing signal, and the output width meets the line synchronizing signal of the horizontal flyback period of the described image brightness signal that receives; Described isolated field sync signal is handled, and the output width meets the field sync signal of the field flyback period of the described image brightness signal that receives;
Step S203 is according to the line synchronizing signal and the field sync signal control brightness of backlight of described output, so that backlight is closed in the line retrace sweep time and the field flyback of picture signal sweep time.
The embodiment of the invention is in image display process, and the brightness of backlight is followed the variation of brightness of image and changed, greatly reduce in the image display process, and the power attenuation of backlight, and then reduced power supply energy, and improved the contrast of LCD.
Above disclosed is preferred embodiment of the present invention only, can not limit the present invention's interest field certainly with this, and therefore the equivalent variations of doing according to claim of the present invention still belongs to the scope that the present invention is contained.
Claims (12)
1, a kind of image brightness controlling circuit is characterized in that, comprising:
Receiving element is used to receive image brightness signal;
Processing unit, the brightness degree of the luminance signal that is used to judge that described receiving element receives, and generate and output image brightness control signal and brightness of backlight control signal according to described result of determination;
Control module, be used for by the described brightness of image control signal control chart image brightness of described processing unit output and by described brightness of backlight control signal control brightness of backlight, so that the requirement of the determined brightness degree of described processing unit is satisfied in the brightness of the picture signal that shows.
2, image brightness controlling circuit as claimed in claim 1 is characterized in that, described processing unit comprises:
Peak detection unit is used to detect the peak value of the luminance signal that described receiving element receives;
First storage unit is used for the brightness degree criterion of memory image luminance signal;
Determining unit is used for described criterion and the detected described peak value of described peak detection unit according to described cell stores, determines the brightness degree of the luminance signal that described receiving element receives;
Generation unit is used for generating and export corresponding brightness of image control signal and brightness of backlight control signal according to the determined described brightness degree of described determining unit.
3, image brightness controlling circuit as claimed in claim 2 is characterized in that, described peak detection unit comprises:
Detecting unit is used to detect the peak value of the luminance signal that described receiving element receives;
Second storage unit is used to store the detected peak value of described detecting unit.
4, image brightness controlling circuit as claimed in claim 1 is characterized in that, described adjusting control module comprises:
The brightness of image control module is used for the described brightness of image control signal control chart image brightness according to described processing unit output;
The brightness of backlight control module is used for the described brightness of backlight control signal control brightness of backlight according to described processing unit output.
5, image brightness controlling circuit as claimed in claim 4 is characterized in that, also comprises:
The synchronizing signal processing unit, be used for the synchronizing signal that receives is handled, and export width respectively and meet the field sync signal that the line synchronizing signal of horizontal flyback period of the image brightness signal that described receiving element receives and width meet the field flyback period of the image brightness signal that described receiving element receives and give described brightness of backlight control module, so that described brightness of backlight control module control backlight is closed in the line retrace sweep time and the field flyback of picture signal sweep time.
6, image brightness controlling circuit as claimed in claim 5 is characterized in that, described synchronous control unit comprises:
Synchronous Signal Receiver Unit is used to receive synchronizing signal;
Synchronous signal separation unit, the described synchronizing signal that is used for described synchronous Signal Receiver Unit is received is separated into line synchronizing signal and field sync signal;
The line synchronizing signal processing unit is used for the line synchronizing signal of described synchronous signal separation unit output is handled, and the output width meets the line synchronizing signal of the horizontal flyback period of the image brightness signal that described receiving element receives;
The field sync signal processing unit is used for the field sync signal of described synchronous signal separation unit output is handled, and the output width meets the field sync signal of the field flyback period of the image brightness signal that described receiving element receives.
7, a kind of LCD, comprise backlight, backlight power circuit and the liquid crystal panel that is positioned at described backlight the place ahead, it is characterized in that, this LCD also comprises an image brightness controlling circuit, link to each other with described liquid crystal panel with described backlight power circuit respectively, described image brightness controlling circuit comprises:
Receiving element is used to receive image brightness signal;
Processing unit, the brightness degree of the luminance signal that is used to judge that described receiving element receives, and generate and output image brightness control signal and brightness of backlight control signal according to described result of determination;
Control module, be used for by the described brightness of image control signal control chart image brightness of described processing unit output and by described brightness of backlight control signal control brightness of backlight, so that the requirement of the determined brightness degree of described processing unit is satisfied in the brightness of the picture signal that shows.
8, a kind of image brightness control method is characterized in that, comprising:
Receive image brightness signal;
Judge the brightness degree of received image brightness signal, and according to described brightness degree output image brightness control signal and brightness of backlight control signal;
By the described brightness of image control signal control chart image brightness of described processing unit output and by described brightness of backlight control signal control brightness of backlight, so that the requirement of described definite brightness degree is satisfied in the brightness of the picture signal of demonstration.
9, image brightness control method as claimed in claim 8, it is characterized in that, the brightness degree of the image brightness signal that described judgement is received, and comprise according to the step of described brightness degree output image brightness control signal and brightness of backlight control signal:
Detect the peak value of the described luminance signal that receives;
Be used for determining the brightness degree of the described luminance signal that receives according to the brightness degree criterion of the image brightness signal of storing and the peak value of described detected luminance signal;
Be used for according to described definite brightness degree, generate and output image brightness control signal and brightness of backlight control signal.
10, image brightness control method as claimed in claim 9 is characterized in that, also comprises behind the peak value of the received luminance signal of described detection:
Described peak value is preserved.
11, as each described image brightness control method among the claim 8-10, it is characterized in that, also comprise:
When receiving image brightness signal, receive synchronizing signal;
The synchronizing signal of described reception is separated into line synchronizing signal and field sync signal;
Described isolated line synchronizing signal is handled, and the output width meets the line synchronizing signal of the horizontal flyback period of the described image brightness signal that receives; Described isolated field sync signal is handled, and the output width meets the field sync signal of the field flyback period of the described image brightness signal that receives;
According to the line synchronizing signal and the field sync signal control brightness of backlight of described output, so that backlight is closed in the line retrace sweep time and the field flyback of picture signal sweep time.
12, as each described image brightness control method among the claim 8-10, it is characterized in that the value of described brightness of backlight control signal is more than or equal to the maximal value of described image brightness signal.
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| Application Number | Priority Date | Filing Date | Title |
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| CNA2007100303682A CN101393725A (en) | 2007-09-21 | 2007-09-21 | Liquid crystal display device, image brightness controlling circuit and method |
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| Application Number | Priority Date | Filing Date | Title |
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| CNA2007100303682A CN101393725A (en) | 2007-09-21 | 2007-09-21 | Liquid crystal display device, image brightness controlling circuit and method |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102088541A (en) * | 2009-12-02 | 2011-06-08 | 康佳集团股份有限公司 | Method, device and television set for recovering video line synchronization |
| CN102682716A (en) * | 2012-04-28 | 2012-09-19 | 深圳光启创新技术有限公司 | Method and device for regulating screen brightness and electronic device |
| CN105141862A (en) * | 2015-07-06 | 2015-12-09 | Tcl海外电子（惠州）有限公司 | Field frequency synchronous backlight control method, field frequency synchronous backlight control device and television set |
| CN106448556A (en) * | 2016-12-20 | 2017-02-22 | 珠海市魅族科技有限公司 | Method of adjusting OLED screen display and device thereof |
| WO2017120995A1 (en) * | 2016-01-15 | 2017-07-20 | 深圳市华星光电技术有限公司 | Power regulation circuit and liquid crystal display device |
| CN110335570A (en) * | 2019-05-08 | 2019-10-15 | 京东方科技集团股份有限公司 | Consumption control method, system and device, computer readable storage medium |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102088541A (en) * | 2009-12-02 | 2011-06-08 | 康佳集团股份有限公司 | Method, device and television set for recovering video line synchronization |
| CN102682716A (en) * | 2012-04-28 | 2012-09-19 | 深圳光启创新技术有限公司 | Method and device for regulating screen brightness and electronic device |
| CN105141862A (en) * | 2015-07-06 | 2015-12-09 | Tcl海外电子（惠州）有限公司 | Field frequency synchronous backlight control method, field frequency synchronous backlight control device and television set |
| WO2017120995A1 (en) * | 2016-01-15 | 2017-07-20 | 深圳市华星光电技术有限公司 | Power regulation circuit and liquid crystal display device |
| CN106448556A (en) * | 2016-12-20 | 2017-02-22 | 珠海市魅族科技有限公司 | Method of adjusting OLED screen display and device thereof |
| CN110335570A (en) * | 2019-05-08 | 2019-10-15 | 京东方科技集团股份有限公司 | Consumption control method, system and device, computer readable storage medium |
| CN110335570B (en) * | 2019-05-08 | 2021-08-31 | 京东方科技集团股份有限公司 | Energy consumption control method, system and device and computer readable storage medium |
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