The flicker detection method of liquid crystal panel
Technical field
The invention relates to the detection method of a kind of liquid crystal panel (liquidcrystalpanel), and particularly relevant for a kind of flicker (flicker) detection method of liquid crystal panel.
Background technology
(LiquidCrystalDisplay, in manufacture process LCD), can glimmer usually (flicker) detects, and adjusts input voltage according to the result who detects, to reduce the situation that film flicker takes place in present LCD.Present flicker detection is that (LiquidCrystalModule LCM) detects to LCD MODULE mostly.
Figure 1A is the time dependent synoptic diagram of the voltage signal of known LCD MODULE when carrying out flicker detection.See also Figure 1A, LCD MODULE normally utilizes a forward bias VD1 and a reverse biased VD2 to drive, and wherein forward bias VD1 is greater than common electric voltage Vc, and reverse biased VD2 is less than common electric voltage Vc.When forward bias VD1 and reverse biased VD2 alternately inputed to pixel electrode, liquid crystal molecule can be subjected to two opposite each other electric fields of direction and drive, and allows the mode of LCD MODULE reversal of poles (polarityinversion) drive.
LCD MODULE normally utilizes gate voltage signal Vg to control forward bias VD1 and the reverse biased VD2 input to pixel electrode.When gate voltage signal Vg imported with high levels Vgh, forward bias VD1 or reverse biased VD2 can input to pixel electrode.When gate voltage signal Vg imported with low level Vgl, forward bias VD1 can be reduced to forward bias Vd1, or reverse biased VD2 can be reduced to reverse biased Vd2, shown in Figure 1A.
Hold above-mentioned, forward bias VD1 is reduced to the amplitude of forward bias Vd1 and amplitude that reverse biased VD2 is reduced to reverse biased Vd2 about equally, and the pressure reduction between forward bias VD1 and the forward bias Vd1, and the pressure reduction between reverse biased VD2 and the reverse biased Vd2 the two be all a pressure reduction △ Vp, wherein pressure reduction △ Vp is called and recalcitrates voltage (kickbackvoltage) or feed-trough voltage (feedthroughvoltage).
The two average voltage Vm and the pressure reduction between the common electric voltage Vc of forward bias VD1 and reverse biased VD2 is a bucking voltage Vo; wherein bucking voltage Vo approximates pressure reduction △ Vp; common electric voltage Vc is generally definite value; and the two definition such as following mathematical expression (1) of average voltage Vm and bucking voltage Vo; (2) shown in: Vo=│ Vm – Vc │ Vm=(VD1+VD2) 1/2.........................................(1) ... ... ... ... ... ... ... ... .(2) in order to reduce the situation that film flicker takes place, the pressure reduction between common electric voltage Vc and the forward bias Vd1 can be adjusted to usually and common electric voltage Vc and reverse biased Vd2 between pressure reduction suitable.
Yet in truth, average voltage Vm is not a definite value, and can change along with the change of GTG value.Because common electric voltage Vc is definite value, and bucking voltage Vo is the pressure reduction between average voltage Vm and the common electric voltage Vc, so bucking voltage Vo also can change along with the variation of GTG value.
See also Figure 1A and Figure 1B, the curve synoptic diagram that changes for the corresponding GTG value of the bucking voltage of the brilliant display module of regular black liquor (normallyblackLCM) of Figure 1B wherein, and the brilliant display module of this regular black liquor be vertical orientation type LCD MODULE (VerticalAlignmentLCM, VALCM).When the GTG value when GTG value M is above, bucking voltage Vo can increase along with the minimizing of GTG value basically.Yet, the GTG value is more little, and the brightness of the picture that LCD MODULE is shown also can be dark more, to such an extent as to scintillation is difficult to be detected by optical instrument, and can't learn bucking voltage Vo less than the variation in the scope of GTG value M, so Figure 1B does not illustrate the curve below GTG value M.
When GTG value during less than GTG value M, the brightness meeting of picture is too dark and allow scintillation be difficult to be discovered by instrument and naked eyes.Therefore, in the industry of present LCD, a lot of people generally believe: even if omit the scintillation that detects when low order GTG value, ignore bucking voltage Vo less than the variation in the scope of GTG value M, the whole image quality of LCD still can not be affected.
Yet, ignoring bucking voltage Vo but may cause the moving iron (mobileirons) in the liquid crystal layer to pile up less than the variation in the scope of GTG value M, and then generation internal electric field (innerelectricfield), to such an extent as to the situation of direct current residual (DCresidue) may take place the LCD after long-time the use, just when image switching, can image retention occur and destroy the quality of picture.
Summary of the invention
The invention provides a kind of flicker detection method of liquid crystal panel, it can detect the film flicker situation under low order GTG value.
The invention provides a kind of flicker detection method of liquid crystal panel, be used to detect a liquid crystal panel.Liquid crystal panel can be installed in one to have in the LCD MODULE of 8N GTG value, and wherein N is a positive integer.Flicker detection method comprises, at first, liquid crystal panel is interposed between one first polarisation unit and the one second polarisation unit, and wherein the two polarization direction of the first polarisation unit and the second polarisation unit is parallel to each other.Then, utilize a K-1 rank GTG signal to drive liquid crystal panel, wherein K is a positive integer, and K≤N+1.Then, when liquid crystal panel is driven by K-1 rank GTG signal, make a light penetrate the first polarisation unit, liquid crystal panel and the second polarisation unit in regular turn.Then, detect the Strength Changes of light from the second polarisation unit.
In an embodiment of the present invention, 1≤N≤200.
In an embodiment of the present invention, N equals 32.
In an embodiment of the present invention, N equals 16.
In an embodiment of the present invention, N equals 8.
In an embodiment of the present invention, before the Strength Changes of detecting light, more comprise a GTG brightness of correcting liquid crystal panel.
In an embodiment of the present invention, the method for above-mentioned correction GTG brightness comprises, when liquid crystal panel is interposed between the first polarisation unit and the second polarisation unit, makes the two polarization direction of the first polarisation unit and the second polarisation unit be perpendicular to one another.Then, when the two polarization direction of the first polarisation unit and the second polarisation unit is perpendicular to one another, and when light penetrates the first polarisation unit, liquid crystal panel and the second polarisation unit in regular turn, intensity from second polarisation unit detecting light, this moment, liquid crystal panel was driven by a L-1 rank GTG signal, wherein L is a positive integer, and L≤8N.Then, according to the intensity of the light of being detected, adjust an amplitude voltage of L-1 rank GTG signal.
In an embodiment of the present invention, above-mentioned LCD MODULE is a brilliant display module of a regular black liquor or a regular white liquid crystal display module (normallywhiteLCM).
In an embodiment of the present invention, the brilliant display module of above-mentioned regular black liquor is a vertical orientation type LCD MODULE.
In an embodiment of the present invention, above-mentioned regular white liquid crystal display module be the twisted nematic liquid crystals display module (TwistedNematicLCM, TNLCM).
Based on above-mentioned, the present invention utilizes two polarisation unit, before liquid crystal panel is not installed any polarisation unit as yet, liquid crystal panel is carried out flicker detection.See through the polarization direction that changes above-mentioned polarisation unit, the present invention can detect the film flicker situation under low order GTG value.
For above-mentioned feature and advantage of the present invention can be become apparent, embodiment cited below particularly, and cooperate appended graphicly, be described in detail below.
Description of drawings
Figure 1A is the time dependent synoptic diagram of the voltage signal of known LCD MODULE when carrying out flicker detection.
The curve synoptic diagram that Figure 1B changes for the corresponding GTG value of the bucking voltage of the brilliant display module of regular black liquor.
Fig. 2 A is the schematic flow sheet of flicker detection method of the liquid crystal panel of one embodiment of the invention.
Fig. 2 B is the device synoptic diagram of flicker detection method among the execution graph 2A.
Fig. 2 C is a GTG signal time dependent synoptic diagram in K-1 rank among Fig. 2 A.
Fig. 3 is the device synoptic diagram of the GTG brightness of liquid crystal panel among the correction chart 2B.
[primary clustering symbol description] 100 liquid crystal panels 201 first polarisation unit, 202 second polarisation unit 202a exiting surfaces, 300 area source M GTG value R1 light S K-1 rank GTG signal S1, S2 polarization direction S102 ~ S108 step Va amplitude voltage VC, Vc common electric voltage VD1, Vd1, Vh forward bias VD2, Vd2, Vl reverse biased Vg gate voltage signal Vgh high levels Vgl low level VM, Vm average voltage VO, Vo bucking voltage △ Vp pressure reduction.
Embodiment
Fig. 2 A is the schematic flow sheet of flicker detection method of the liquid crystal panel of one embodiment of the invention, and Fig. 2 B is the device synoptic diagram of flicker detection method among the execution graph 2A.See also Fig. 2 A and Fig. 2 B, the flicker detection method of present embodiment is used to detect a liquid crystal panel 100, and wherein liquid crystal panel 100 is not installed any polarisation unit as yet.
Liquid crystal panel 100 can be installed in the LCD MODULE (not illustrating), and this LCD MODULE can be brilliant display module of regular black liquor or regular white liquid crystal display module, the brilliant display module of wherein regular black liquor for example is a vertical orientation type LCD MODULE, and regular white liquid crystal display module for example is the twisted nematic liquid crystals display module.Therefore, the flicker detection method of present embodiment can be applied to brilliant display module of regular black liquor and regular white liquid crystal display module.
Above-mentioned LCD MODULE has 8N GTG value, and wherein N is the positive integer between 1 to 200, i.e. 1≤N≤200.N can equal 8,16 or 32, and LCD MODULE can have 64,128 or 256 GTG values.When LCD MODULE had 64 GTG values, liquid crystal panel 100 can receive from 64 kinds of GTG signals such as 63 rank, the 0th rank to the; When LCD MODULE had 128 GTG values, liquid crystal panel 100 can receive from 128 kinds of GTG signals such as 127 rank, the 0th rank to the; When LCD MODULE had 256 GTG values, liquid crystal panel 100 can receive from 256 kinds of GTG signals such as 255 rank, the 0th rank to the; The rest may be inferred.
In the flicker detection method of present embodiment, at first, carry out step S102, just liquid crystal panel 100 is interposed between one first polarisation unit 201 and the one second polarisation unit 202, wherein the two is parallel to each other for the polarization direction S2 of the polarization direction S1 of the first polarisation unit 201 and the second polarisation unit 202.
The first polarisation unit 201 and the second polarisation unit 202 the two can be all can the rotatory polarization angle the polarisation unit, and in the present embodiment, the first polarisation unit 201 and the second polarisation unit, 202 neither being installed on the liquid crystal panel 100, so in the flicker detection process of present embodiment, liquid crystal panel 100 can't bind with the first polarisation unit 201 and the second polarisation unit 202.
After carrying out step S102, then carry out step S104, promptly utilize a K-1 rank GTG signal to drive liquid crystal panel 100, wherein K-1 rank GTG signal belongs to the GTG signal in the low order GTG value scope.Specifically, when the GTG value had 8N, K was a positive integer, and K≤N+1.For instance, when N equals 8, when promptly the GTG value has 64, K≤9, and K-1 rank GTG signal is the following GTG signals in the 8th rank.When N equals 32, when promptly the GTG value has 256, K≤33, and K-1 rank GTG signal is the following GTG signals in the 32nd rank.
In step S104, K-1 rank GTG signal more can belong to the more GTG signal of low order of GTG value, and promptly K-1 rank GTG signal is very near the 0th rank GTG signal.In detail, when N equaled 8, K can be less than or equal to 3, and K-1 rank GTG signal is the following GTG signals in the 2nd rank.When N equaled 16, K can be less than or equal to 6, and K-1 rank GTG signal is the following GTG signals in the 5th rank.When N equaled 32, K can be less than or equal to 11, and K-1 rank GTG signal is the following GTG signals in the 10th rank.
When liquid crystal panel 100 is driven by K-1 rank GTG signal, carry out step S106, make a light R1 penetrate the first polarisation unit 201, liquid crystal panel 100 and the second polarisation unit 202 in regular turn.Particularly, it is other that an area source (planelightsource) 300 is disposed at the first polarisation unit 201, and towards the first polarisation unit 201, liquid crystal panel 100 and the second polarisation unit 202 R1 that emits beam.
Because driving the K-1 rank GTG signal of liquid crystal panel 100 is in the low order GTG value scope, and the two is parallel to each other for polarization direction S1 and polarization direction S2, therefore after light R1 penetrates the first polarisation unit 201, liquid crystal panel 100 can significantly not change the polarization angle of light R1, allows light R1 can penetrate the liquid crystal panel 100 and the second polarisation unit 202 in regular turn.
After carrying out step S106, then carry out step S108, from the Strength Changes of the second polarisation unit, 202 detecting light R1, the brightness of just detecting the exiting surface 202a of the second polarisation unit 202 changes, and then learns the flicker situation of exiting surface 202a.When carrying out step S108, according to the Strength Changes of light R1, can adjust the average voltage of K-1 rank GTG signal simultaneously, reduce the flicker situation of exiting surface 202a.
Fig. 2 C is a GTG signal time dependent synoptic diagram in K-1 rank among Fig. 2 A.See also Fig. 2 B and Fig. 2 C, K-1 rank GTG signal S has a forward bias Vh, a reverse biased Vl and an average voltage VM, wherein the definition of average voltage VM is shown in following mathematical expression (3): VM=(Vh+Vl) 1/2..............................................(3) forward bias Vh presses VC greater than switching on altogether, and reverse biased Vl is less than common electric voltage VC.Common electric voltage VC can be definite value, and the pressure reduction between average voltage VM and the common electric voltage VC is a bucking voltage VO, be the two definition of average voltage VM and bucking voltage VO shown in following mathematical expression (4): VO=│ VM – VC │ ... ... ... ... ... ... ... ... (4) in addition, K-1 rank GTG signal S has more an amplitude voltage Va, and the definition of amplitude voltage Va is shown in following mathematical expression (5): Va=(Vh-Vl) 1/2...........................................(5) amplitude voltage Va is relevant with the GTG value.Specifically, adjust the brightness that amplitude voltage Va can control exiting surface 202a, and then adjust the GTG value.Therefore, see through and adjust amplitude voltage Va, can allow the brightness of exiting surface 202a meet K-1 rank GTG value.
Before the Strength Changes of detecting light R1, the GTG brightness that present embodiment more can correcting liquid crystal panel 100 allows the brightness of exiting surface 202a can corresponding each rank GTG value.Specifically, see also Fig. 3, it is the device synoptic diagram of the GTG brightness of liquid crystal panel among the correction chart 2B.
The method of above-mentioned correction GTG brightness can may further comprise the steps.When liquid crystal panel 100 is interposed between the first polarisation unit 201 and the second polarisation unit 202, make the two polarization direction S1, S2 of the first polarisation unit 201 and the second polarisation unit 202 be perpendicular to one another.Because the two is all energy rotatory polarization angle the first polarisation unit 201 and the second polarisation unit 202, so polarization direction S1, S2 can rotate to the two and be perpendicular to one another.
When polarization direction S1 is perpendicular to one another with S2, and light R1 from the intensity of the second polarisation unit, 202 detecting light R1, just detects the brightness of exiting surface 202a when penetrating the first polarisation unit 201, liquid crystal panel 100 and the second polarisation unit 202 in regular turn.At this moment, liquid crystal panel 100 is driven by a L-1 rank GTG signal, and wherein L is a positive integer, and L≤8N, so L-1 rank GTG signal is the GTG signal on arbitrary rank in the 8N-1 rank, the 0th rank to the.
Then, intensity according to the light R1 that is detected, adjust the amplitude voltage of L-1 rank GTG signal, wherein the amplitude voltage of L-1 rank GTG signal is the forward bias of L-1 rank GTG signal and half of the two difference of reverse biased, therefore the definition of the amplitude voltage of L-1 rank GTG signal is identical substantially with the amplitude voltage Va shown in the mathematical expression (5), no longer repeated description.The amplitude voltage of adjusting L-1 rank GTG signal can be controlled the brightness of exiting surface 202a, allows the brightness of exiting surface 202a meet L-1 rank GTG value.
What deserves to be mentioned is that utilize Fig. 2 B and device shown in Figure 3, present embodiment can be learnt the flicker situation under all GTG values, learning the bucking voltage of each rank GTG signal, and then adjust the average voltage of all GTG signals.So, the data that concern between amplitude voltage and the bucking voltage, and the data that concern between amplitude voltage and the penetrance all can learn, and these data can be used as the reference data that is used for adjusting LCD MODULE.
In sum, the present invention utilizes two polarisation unit, and the liquid crystal panel of not installing any polarisation unit is as yet carried out flicker detection.See through the polarization direction that changes above-mentioned polarisation unit, the present invention can learn the flicker situation of liquid crystal panel in low order GTG value scope, and then can be adjusted at the average voltage in the low order GTG value scope, reduces flicker appears in picture under low order GTG value situation.
Hence one can see that, the present invention can prevent to pile up moving iron, avoid the generation of internal electric field, and then the residual situation of direct current takes place in minimizing, even even use liquid crystal indicator for a long time, the present invention also can reduce the residual situation of generation direct current effectively, to keep or to improve the image quality of liquid crystal indicator.
Though the present invention discloses as above with previous embodiment, so it is not in order to limiting the present invention, anyly has the knack of alike skill person, and without departing from the spirit and scope of the present invention, institute does to change and the equivalence replacement of retouching, and still is in the scope of patent protection of the present invention.