CN1763831A - Uniformity of luminance compensation process and circuit for display picture surface load effect - Google Patents

Abstract

The invention discloses a brightness uniformity compensation method and circuit of display image load effect, which is characterized by the following: establishing a model according to the relationship of electrode wire conductor length, wire current and potential drop; doing compensation calculation with a preset reference value to change brightness signal data corresponding to luminous unit of random length input according to the relationship value of electrode wire random length and potential drop; reaching the goal of uniformity compensation due to the same brightness of the same image data in different luminous units.

Description

The uniformity of luminance compensation process of display picture surface load effect and circuit

Technical field

The present invention relates to the image data process field, particularly relates to a kind of uniformity of luminance compensation process and circuit of display picture surface load effect.

Background technology

Cathode-ray tube (CRT) has the excellent and cheap characteristics of image quality, thereby be the main flow of televisor and graphoscope always, but along with coming out one after another of Thin Film Transistor-LCD (TFT LCD), plasma scope various flat-panel screens (FPD) such as (PDP), existing tired attitude on market and advantage are no longer.Because the positive commercialization of various flat-panel screens, relevant dealer there's no one who doesn't or isn't drops into a large amount of manpower and materials and seeks technological breakthrough, or promotes production efficiency or improve product quality, also or reduce cost or the like, and in the hope of on market, occupying a tiny space.Described flat-panel screens, mostly be to arrange and formation display frame with intensive matrix form by most luminescence unit (cell), but for the luminescence unit that needs the positive-negative polarity loop, for having bigger aperture opening ratio to promote luminous quantity, mostly adopting the higher transparency electrode of resistance aspect the electrode wires that connects each luminescence unit, or with electrode wires as elongated wire, but its resistance value of elongated lead is high more, the raising of its line resistance, the phenomenon that the load that causes electrode wires is differed is more obvious, thereby luminescence units different on two display lines that charge capacity differs appears when showing identical image data, the inconsistent situation of its brightness by human eye the energy identification.Below sincerely further specify described brightness irregularities defective with the principle of work of plasma scope:

As shown in Figure 7, disclosing the basic framework of a plasma display, mainly is to be formed with most data electrode wires 71 in a back on the glass substrate 70 (its distribution situation on the glass substrate 70 of back please cooperate and consults A shown in Fig. 8 B ₁-A _n), and be covered with a dielectric layer 72 above it, be formed with most barrier rib 73 on this dielectric layer 72, and the fluorescent layer 74 that is coated with heterogeneity respectively on the opposing sidewalls and corresponding dielectric layer 72 surfaces of adjacent barrier rib 73, it can send the coloured light of different wave length after absorbing ultraviolet (UV), person shown in the figure is suitable be that the structural representation of single pixel, meaning are that three road fluorescent layers 74 of 73 of adjacent barrier ribs produce the three primary colors of RGB respectively to constitute a pixel after the absorption ultraviolet ray.

Described plasma scope further comprises a front glass substrate 80, and the lower surface of this front glass substrate 80 is formed with paired transparency electrode 81 (Transparent Electrode), metal electrode lines X, Y in regular turn; Wherein, metal electrode lines Y makes sweep trace to use, and in order only to allow specific luminescence unit luminous, the lateral metal electrode configuration line Y that connects this luminescence unit was scanned then in scan period, the longitudinal data electrode 71 that this luminescence unit is connected on the glass substrate 70 of back will have correspondence to make it to produce with metal electrode lines Y the data-signal of discharge, so that X, dielectric layer 82 under the Y electrode wires can be accumulated suitable positive and negative charge, so during long luminous the keeping of follow-up time width, metal electrode lines X, the voltage of keeping on the Y adds that the magnitude of voltage of positive and negative charge formation is luminous even as big as making noble gas discharge.Otherwise, in scan period, if make it to produce the data-signal of discharge on the data electrode 71 with metal electrode lines Y, then during luminous keeping keep that magnitude of voltage is not sufficient to make noble gas discharge and can be not luminous.Using transparency electrode 81 again is to be increase aperture opening ratio and brightness, but itself is high impedance, thus thereunder establish metal electrode lines X with auxiliary usefulness, Y, to reduce electrode wires resistance, auxiliary transparency electrode 81 causes discharges.For avoiding causing luminous obstruction and brightness to reduce, metal electrode lines X, Y should be very thin as far as possible in addition, and its distribution situation on front glass substrate 80 please cooperate consults shown in Fig. 8 A, this metal electrode lines X ₁-X _m, Y ₁-Y _mSignal input part lay respectively on the relative two ends, and the two is to make parallel crossover with suitable distance in indication range.And at described transparency electrode 81 and metal electrode lines X, the skin relatively of Y then is a dielectric layer 82 and a protective seam 83 in regular turn.

After front/rear glass substrate 80/70 relative combination, promptly be filled with inert gas 80/70 of relative front/rear glass substrate.Its work principle of luminosity is then closely similar with daylight lamp, as the pairing two metal electrode lines X of a luminescence unit, form enough big voltage difference between the Y, then can make the noble gas discharge of filling and produce ultraviolet ray, ultraviolet then by be coated on fluorescent layer 74 on the adjacent barrier rib 73 absorption to produce the coloured light of specific wavelength.

By the above-mentioned basic functional principle of finding out plasma scope, and that desire to be inquired into is the metal electrode lines X of front glass substrate 80 herein, Y is made into elongate for the aperture opening ratio that enlarges luminescence unit, but also thereby produce higher line resistance, and many bad effects of deriving:

1. produce voltage drop owing to electrode wires resistance will make it, and make the input voltage of the luminescence unit that is positioned at the panel middle section lower than the luminescence unit at close end points place;

2. for load electrode wires not of uniform size, the input voltage of load luminescence unit that weight person connects will be lower than load the lighter.

Because the luminous intensity of luminescence unit generally is to be directly proportional with its input voltage, described two kinds of load effects that situation presented will produce following influence to the equal-sized input signal of brightness:

1. two end regions are brighter than middle section;

2. two display lines differing of load the inconsistent situation of brightness can occur when showing identical image data.

No doubt address the above problem and to set about by modes such as reducing electrode wires resistance or minimizing current sinking, but when described two kinds of modes are all infeasible, still must find out feasible solution.

Summary of the invention

The technical matters that the present invention solves is: the present invention adopts image treatment method that the luminescence unit with same image data is carried out luminance compensation, to solve the brightness irregularities phenomenon that it is caused because of the pressure drop loss.

Solve the problems of the technologies described above for reaching: the invention provides a kind of display that can effectively improve and cause the compensation method of brightness irregularities of deriving that differs of each luminescence unit driving voltage because of the electrode wires line resistance.Mainly be to calculate electrode wires resistance earlier for the voltage drop that each luminescence unit produced, with the luminous quantity of image processing mode compensation luminescence unit, its concrete steps comprise again:

Relation according to conductor length, line resistance and the electric current of electrode wires is set up a voltage drop distributed model, and computing obtains the pressure drop relation value at electrode wires random length place;

A described voltage drop value relation value and a preset reference value compensate computing, input to the luminance signal data of the corresponding luminescence unit in this random length place (cell) with change.

In addition, the present invention also provides a kind of brightness uniformity compensating circuit of display picture surface load effect, comprising:

One impact damper, its input end are to connect luminance signal data Pi, and its output terminal then is not the luminance signal data P that inputs to any point k place luminescence unit on the electrode wires before the luminance compensation in order to produce _k

One pressure drop arithmetic element, its input end respectively with described luminance signal data Pi/P _kConnect, and computing according to this produces a relation value T _DkAnd

One luminance compensation arithmetic element, its input end connect the output terminal and the relation value T with reference to luminescence unit of described luminance signal data Pi, pressure drop arithmetic element respectively _Dref, its output terminal is then in order to produce the luminance signal data P that delivers to arbitrary luminescence unit on the electrode wires once over-compensation _k'.

Compared with prior art, the invention has the beneficial effects as follows: adopt image treatment method that the luminescence unit with same image data is carried out luminance compensation, and the different luminescence units that utilize described method can make electrode wires different length place correspondence have identical brightness when showing the same image data, with the purpose of the homogeneity compensation that reaches its brightness irregularities phenomenon that is caused because of the pressure drop loss.

Description of drawings

Fig. 1: be electrode wires X, the performance diagram when last each luminescence unit of Y consumes same current.

Fig. 2: be electrode wires X, the voltage drop scatter chart of each luminescence unit of Y.

Fig. 3: be electrode wires X, Y is connected the circuit distributed model synoptic diagram of luminescence unit with each.

Fig. 4: be brightness uniformity compensating circuit calcspar of the present invention.

Fig. 5: be the pressure drop arithmetic element calcspar in the brightness uniformity compensating circuit of the present invention.

Fig. 6: be the luminance compensation arithmetic element calcspar in the brightness uniformity compensating circuit of the present invention.

Fig. 7: the organigram that is the single pixel of known plasma scope.

Fig. 8 A: be the X on the known plasm display panel, Y metal electrode lines distribution schematic diagram.

Fig. 8 B: be the data electrode wire distribution schematic diagram on the known plasm display panel.

The figure number explanation

10, impact damper 20, pressure drop arithmetic element

21, following counter 22,23, buffer

24,25, selector switch 26,27, multiplier

30, luminance compensation arithmetic element 31, the table of comparisons

32, multiplier 33,34, subtracter

70, back glass substrate 71, data electrode wire

72, dielectric layer 73, barrier layer

74, fluorescent layer 80, front glass substrate

81, transparency electrode 82, dielectric layer

83, protective seam

Embodiment

At first in order to understand the load effect that produces because of the electrode wires pressure drop, below still its generation mechanism is described with plasma scope:

Because plasma scope luminous is because of being applied to metal electrode lines X on the front glass substrate, the keeping drive waveforms (Sustain Pulse) of Y and moving, therefore with regard to this electrode wires X, the loop of Y illustrates the generation of load effect.

Derive to understand the formation of load effect, so make following hypothesis earlier for simplifying:

1. electrode wires X, the line resistance of Y evenly distribute.

2. at electrode wires X, Y discharge range, electric current are continuity along electrode wires to be changed.

According to above-mentioned hypothesis, if the input current of electrode wires is I _b, and electrode wires X, the length of the parallel crossover of Y is L, then please cooperate consult shown in Figure 1:

Electric current I x on the electrode wires X (l)=I _b* (1-l/L);

Electric current I y on the electrode wires Y (l)=I _b* (l/L);

Electrode wires resistance R (l)=ρ * l/A; Wherein, ρ is the resistance coefficient of electrode wires, A is the electrode wires sectional area, l then is an electrode wires length, then one minimum section line resistance is dR=ρ/A * dl, therefore, and for the luminescence unit at any point k place on the electrode wires, it is to electrode wires X, and the Y two-end-point on electrode wires because of voltage drop that line resistance produced then is

$V_d={\∫}_0^k\mathrm{IxdR}+{\∫}_k^L\mathrm{IydR}$

$=\mathrm{\ρ}/A\×I_b\×(k-k^2/L+L/2)$

By following formula as can be known, the voltage drop maximal value is to occur in its value of k=L/2 to be V on the electrode wires _{D, max}=ρ/A * I _bK=0 and k=L place then take place in the minimum value of * L * 3/4 voltage drop

Its value is V _{D, min}=ρ/A * I _b* L/2

Suppose electrode wires X, the input voltage Vs of Y two-end-point, then at electrode wires X, the voltage difference of the corresponding region of discharge in k place, Y overlapping line segment arbitrfary point is

V _X，Y(k)＝Vs-Vd

And can find out voltage drop distribution situation on the entire electrode line by Fig. 2.

After understanding the voltage drop situation that exists on the electrode wires, adopt image treatment method to compensate again for the pressure drop loss that on luminescence unit, produces, so-called image treatment method, be to see through to change the luminance signal data that inputs to luminescence unit, to compensate luminance difference because of pressure drop was produced, desire to reach the concrete practice of the technical matters that will solve, at first must further understand the voltage drop distribution situation on the electrode wires.

For this reason, the present invention is electrode wires X, the circuit modelization (as shown in Figure 3) that Y overlapping line segment is connected with luminescence unit, and wherein n is a panel luminescence unit sum in the horizontal direction, can obtain electrode wires X by this model, the last any point k of Y place connects luminescence unit to electrode wires two-end-point X ₀, Y ₀Because of the voltage drop that line resistance produced

$\begin{array}{c}{V}_{\mathrm{dk}}=[\underset{i=2}{\overset{n}{\mathrm{\Σ}}}\mathrm{Ii\ΔR}+\underset{i=3}{\overset{n}{\mathrm{\Σ}}}\mathrm{Ii\ΔR}+\·\·\·+\underset{i=k}{\overset{n}{\mathrm{\Σ}}}\mathrm{Ii\ΔR}]+[\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{Ii\ΔR}+\underset{i=1}{\overset{k+1}{\mathrm{\Σ}}}\mathrm{Ii\ΔR}+\·\·\·+\underset{i=1}{\overset{n-1}{\mathrm{\Σ}}}\mathrm{Ii\ΔR}]\\ =[\underset{j=2}{\overset{k}{\mathrm{\Σ}}}\underset{i=j}{\overset{n}{\mathrm{\Σ}}}\mathrm{Ii\ΔR}+\underset{j=k}{\overset{n-1}{\mathrm{\Σ}}}\underset{i=1}{\overset{j}{\mathrm{\Σ}}}\mathrm{Ii\ΔR}]\end{array}$

Wherein Ii represents to flow through the electric current of i luminescence unit, Δ R be luminescence unit between line resistance on institute's counter electrode line, and $\mathrm{\ΔR}=\frac{\mathrm{Rx}}{(n-1)}$

Can get through the arrangement following formula

${\mathrm{<figure-callout\; id="1"\; label="V\; d"\; filenames="A20041008644900141.png"\; state="\{\{state\}\}">V</figure-callout>}}_d=\underset{j=1}{\overset{n-1}{\mathrm{\&Sigma;}}}\underset{i=1}{\overset{j}{\mathrm{\&Sigma;}}}{I}_i\mathrm{\&Delta;R}$

V _d2＝V _d1-I ₁ΔR+(I _b-I ₁)ΔR＝V _d1+(I _b-2I ₁)ΔR

＝V _d1+S ₁·ΔR

V _d3＝V _d2-(I ₁+I ₂)ΔR+(I _b-I ₁-I ₂)ΔR＝V _d2+(I _b-2I ₁-2I ₂)ΔR

＝V _d2+S ₂·ΔR

·

·

·

V _dk＝V _d(k-1)+S _k-1·ΔR

S wherein _k=S _K-1-2I _k, work as k1

=I _b, work as k=0

And arbitrfary point k and end points X ₀Because of the pressure drop difference that is caused on the line resistance is

ΔV _dk＝V _dk-V _dl

$=\underset{i=1}{\overset{k-1}{\mathrm{\&Sigma;}}}{S}_i\mathrm{\&Delta;R},1<k<n$

According to above-mentioned model, can obtain the pressure drop of all luminescence units on the single display line, and as described in disclosing, the present invention utilizes to change the luminance difference that luminance signal data is caused because of the pressure drop loss with compensation, and luminance signal data is directly proportional with the electric current that flows through luminescence unit, so make the pressure drop loss of k luminescence unit on every strip electrode line, obtain a relation value T who is directly proportional with luminance signal data Pi _Dk, T wherein _Dk=a * V _Dk, and a is a constant, following formula is multiplied by a is:

a×V _dk＝a×V _d(k-1)+a×S _k-1×ΔR

T _Dk=T _{D (k-1)}+ U _K-1When k＞1

$=a\&times;{\mathrm{<figure-callout\; id="1"\; label="V\; d"\; filenames="A20041008644900141.png"\; state="\{\{state\}\}">V</figure-callout>}}_d=\underset{j=1}{\overset{n-1}{\mathrm{\&Sigma;}}}\underset{i=1}{\overset{j}{\mathrm{\&Sigma;}}}a\&times;\mathrm{Ii\&Delta;R}=\underset{j=1}{\overset{n-1}{\mathrm{\&Sigma;}}}\underset{i=1}{\overset{j}{\mathrm{\&Sigma;}}}\mathrm{Pi},$ Work as k=1, wherein

U _k＝a×S _k×ΔR

＝a×(S _k-1-2×I _k)×ΔR

＝U _k-1-a×2×I _k×ΔR

＝U _k-1-2P _k k≥1

$=a{S}_0\mathrm{\&Delta;R}=a\&times;I_b\&times;\mathrm{\&Delta;R}=P_b=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\mathrm{Pi}----k=0$

By the derivation of following formula as can be known, a * Δ R * I _i=P _i, promptly

A=Δ R * I _i=P _i/ I _i, because luminance signal P _iWith the electric current I that flows through luminescence unit i _iLinear ratio, and Δ R is a constant, thus a also is a constant.

And utilize described relation value T _DkCan compensate because of the caused luminance difference of load effect.

Again for the different luminescence units that make same display data have consistent brightness, thus preset one with reference to luminescence unit, and to make this line resistance pressure drop with reference to luminescence unit be V _Dref, corresponding relation value is T _Dref, T wherein _Dref=a * V _Dref

Can compensate because of the luminance difference that the pressure drop loss is caused luminescence unit according to this according to described model and relational expression, as shown in Figure 4, be a circuit block diagram of the present invention, and it includes:

One impact damper 10 is made of an internal memory in present embodiment, and its input end connects luminance signal data Pi, and its output terminal then is the output P behind horizontal cycle of luminance signal data delay _k

One pressure drop arithmetic element 20, its input end respectively with described luminance signal data Pi/P _kConnect, and computing according to this produces above-mentioned relation value T _Dk

One luminance compensation arithmetic element 30, its input end connect described luminance signal data P respectively _k, pressure drop arithmetic element 20 output terminal and with reference to the relation value T of luminescence unit _Dref, its output terminal is then in order to produce the luminance signal data P that delivers to arbitrary luminescence unit on the electrode wires once over-compensation _k'; Wherein:

This pressure drop arithmetic element 20 further circuit are formed as shown in Figure 5, are made up of once counter 21, two buffers 22,23, two selector switchs 24,25, two multipliers 26,27, a subtracter and several totalizers, and the expression formula of its execution is as following:

T _dk＝T _d(k-1)+U _k-1，k＞1

$=\underset{j=1}{\overset{n-1}{\mathrm{\&Sigma;}}}\underset{i=1}{\overset{j}{\mathrm{\&Sigma;}}}{P}_i,k=1$

U _k＝U _k-1-2×P _k,k≥1

$=P_b=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{P}_i,k=0$

According to following formula to calculate its luminance signal data P of any point k place on the electrode wires _kWith pressure drop V _DkRelation value T _Dk

The concrete framework of described again luminance compensation arithmetic element 30 sees also shown in Figure 6, comprises comparison list (Look Up Table) 31, one multiplier 32 and two subtracters 33,34 etc., in order to carry out following expression formula:

P _k’＝P _k-α(P _k)×(T _dref-T _dk)

α (P wherein _k) be to obtain by the panel experimental measurement, it is stored in the table of comparisons 31, by way of compensation the usefulness of computing.

Can find out that by above-mentioned explanation the present invention carries out the evenly concrete technology contents of compensation of brightness, for example, as the luminance signal data of delivering to each luminescence unit on the same display line is 100 gray scale unit, because of influenced by the pressure drop loss, its gray scale unit of luminescence unit that is positioned at central authorities may have only 80 or 90, and use described method that the gray scale unit of this luminescence unit is increased to 110, so can make the different luminescence units that show the same image data have same brightness, and reach the purpose of brightness uniformity compensation.

Again with regard to the plasma scope of being carried among the embodiment, because each luminescence unit is at its sub-frame (SF, the data that can only show a position Sub Frame) are so can't carry out calculation process (becoming big because of significance bit place deficiency will cause the error of computing) again as following formula.But generally speaking, the image data of plasma scope is before the data video picture that is divided into each single position, and its load effect still has the relation that is similar to following formula, so still can utilize the present invention to improve the load effect of plasma scope.

Though the present invention with preferred embodiment openly as above; right its is not in order to limiting the present invention, anyly is familiar with this skill person, without departing from the spirit and scope of the present invention; when can doing a little change and retouching, so protection scope of the present invention is as the criterion when looking the claim person of defining.

Claims (8)

1. the uniformity of luminance compensation process of a display picture surface load effect is characterized in that, comprises the following steps:

Relation according to conductor length, line resistance and the electric current of electrode wires is set up a voltage drop distributed model, obtains the pressure drop at electrode wires random length place according to this; And

Utilize described voltage drop value and to input to the proportional relation of the luminance signal data of set luminescence unit on the electrode wires, change the luminance signal data that inputs to the corresponding luminescence unit in this random length place according to this.

2. according to the uniformity of luminance compensation process of the described display picture surface load effect of claim 1, it is characterized in that, the pressure drop at electrode wires random length place is to be to produce a relation value with proportional relation with the luminance signal data that inputs to this corresponding luminescence unit in random length place, and a default referring-to relation value compensates computing according to this.

3. according to the uniformity of luminance compensation process of the described display picture surface load effect of claim 2, it is characterized in that this referring-to relation value is default one with reference to luminescence unit, and make after its line resistance pressure drop and produce.

4. the brightness uniformity compensating circuit of a display picture surface load effect is characterized in that, comprising:

One impact damper, its input end are to connect luminance signal data Pi, and its output terminal then is not the luminance signal data P that inputs to any point k place luminescence unit on the electrode wires before the luminance compensation in order to produce _k

One pressure drop arithmetic element, its input end respectively with described luminance signal data Pi/P _kConnect, and computing according to this produces a relation value T _DkAnd

One luminance compensation arithmetic element, its input end connect the output terminal and the relation value T with reference to luminescence unit of described luminance signal data Pi, pressure drop arithmetic element respectively _Dref, its output terminal is then in order to produce the luminance signal data P that delivers to arbitrary luminescence unit on the electrode wires once over-compensation _k'.

5. according to the brightness uniformity compensating circuit of the described display picture surface load effect of claim 4, it is characterized in that the expression formula that this pressure drop arithmetic element is carried out is as following:

$T_{\mathrm{dk}}=T_{d(k-1)}+U_{k-1},k>1$

$=\underset{j=1}{\overset{n-1}{\mathrm{\&Sigma;}}}\underset{i=1}{\overset{j}{\mathrm{\&Sigma;}}}\mathrm{Pi},k=1$

$U_k=U_{k-1}-2\&times;P_k,k\&GreaterEqual;1$

$=P_b=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\mathrm{Pi},k=0$

Formula is for calculating its luminance signal data P of any point k place on the electrode wires before utilizing _kWith pressure drop V _DkRelation value T _Dk

6. according to the brightness uniformity compensating circuit of the described display picture surface load effect of claim 4, it is characterized in that this luminance compensation arithmetic element is in order to carry out following expression formula:

P _k’＝P _k-α(P _k)×(T _dref-T _dk)

7. according to the brightness uniformity compensating circuit of claim 4 or 5 described display picture surface load effects, it is characterized in that this α (P _k) value is to be stored in the comparison list, the usefulness of computing by way of compensation.

8. according to the brightness uniformity compensating circuit of the described display picture surface load effect of claim 7, it is characterized in that this α (P _k) value is to obtain by the panel experimental measurement.

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