CN102789759B

CN102789759B - Method for improving contrast of PDP (Plasma Display Panel)

Info

Publication number: CN102789759B
Application number: CN201210266476.0A
Authority: CN
Inventors: 陈泽祥; 董淼; 胡添勇
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2012-07-30
Filing date: 2012-07-30
Publication date: 2015-07-22
Anticipated expiration: 2032-07-30
Also published as: CN102789759A

Abstract

The invention provides a method for improving the contrast of a PDP (Plasma Display Panel). A filter membrane with adjustable transmissivity is introduced to the outer side of a PDP screen, and in the driving mode of the PDP, at a preparation period and an addressing period, a voltage is fed between a horizontal electrode and a vertical electrode, the transmissivity of the filter membrane is the lowest, and the brightness of background light is reduced; and at a maintenance period, an opposite polarity voltage is fed, the transmissivity of the filter membrane is the highest so as to improve the transmissivity of an addressing unit to be lightened, and the strength of emergent light is improved, so that the contrast is greatly improved.

Description

A kind of method improving PDP contrast

Technical field

The present invention relates to a kind of Driving technique of PDP screen, provide a kind of by the light filter film technology of this Driving technique in conjunction with the quick real-time, tunable of transmitance, the transmitance and the reflectivity that adjust filter coating in real time can be realized under the type of drive that PDP is special, thus increase substantially the contrast of PDP.

Background technology

PDP utilizes gas discharge luminescence to carry out the flat-panel monitor shown, and is made up of display screen body and Circuits System two parts, and wherein display screen body is display luminous component.At present, the principal element that restriction PDP further develops is brightness and contrast.In order to obtain very high light-room contrast, PDP display has installed filter coating in the dead ahead of display screen, and this filter coating thickness is generally 100 ~ 500 μm, and its transmitance is generally 30 ~ 50%, can effectively reduce extraneous light reflectance.But the effective luminous flux that the use of this fixing filter coating also makes PDP shield reduces greatly, raising contrast is made to become conflict with raising brightness.Meanwhile, due to the special type of drive of PDP, unofficially lighting the brightness of period meeting production background at PDP screen, thus contrast is reduced greatly.Affect PDP display contrast height principal element and have light-source brightness, unique type of drive reasons for its use brightness and surround lighting are to the reflecting brightness of display screen.

Contrast evaluates one of most important index of color PDP picture quality, in order to obtain high-quality display image, must improve the contrast of display as much as possible.The contrast (C) of flat-panel monitor refers to display screen white brightness (L _d) and details in a play not acted out on stage, but told through dialogues brightness (L _b) ratio, i.e. C=L _d /l _b.Usually, the contrast of display is divided into darkroom contrast and light-room contrast.Operationally, the luminous situation of display screen as shown in Figure 2

In dark room conditions, L _d=L _d, L _dfor the brightness that display screen shields entirely in vain, L _b=L _b, L _bfor the brightness of the full blank screen of display screen, i.e. bias light.

In bright room environmental, L _d=L _d+ L _ref, L _b=L _b+ L _ref, wherein L _reffor the luminance brightness that display screen reflects because surround lighting irradiates.

From the definition of contrast, the main method improving darkroom contrast when PDP luminescence efficiency is constant is improve luminosity and reduce background luminance, and background luminance is main relevant with the type of drive of PDP uniqueness; And improve the measure that light-room contrast also needs to take in the Structure and energy of color PDP the reflection coefficient reducing display screen surface.

Addressing is generally adopted to be separated the type of drive of (ADS) with display in commercial AC-PDP.In which, a frame comprises several subfield, and a subfield is divided into 3 stages: preparatory stage, address period, maintenance phase.All there is the Discharge illuminating of unit in this three phases.Wherein the luminescence of maintenance phase is that display image is necessary, is effective light L _d; And the unit that preparatory stage all unit (comprising selected cell and non-addressed cells) and address period needs are lighted also can be luminous, but this luminescence is the bias light L not wishing to occur _b.When gray scale shows, each subfield has the electric discharge of preparatory stage and address period, and this can cause background brightness very high, causes contrast very low.Such as: in bright room environmental, in PDP drive waveforms, general reset electric discharge will produce 0.4cd brightness, and total address discharge will produce 0.6 cd brightness.If the brightness of the complete white screen of PDP display screen display is L _dthe brightness that=300 cd, PDP display screen shows full blank screen is L _bit is L that=1cd, PDP shield reflection of ambient light light intensity to external world _ref=2cd, therefore, L under bright room _d=L _d+ L _ref=302 cd, L _b=L _b+ L _ref=3 cd, corresponding light-room contrast is only about 100:1.Similarly, under darkroom, L _d=L _d=300 cd, L _b=L _b=1 cd, corresponding darkroom contrast only has 300:1.

At present, improving the brightness and contrast of PDP display screen, mainly starting with from improving circuit, that improves that drive waveforms reduces the non-maintenance phase lights number of times to reduce background luminance.But this can cause the shortcomings such as judder.The present invention will start with from display screen itself, PDP screen in introduce the adjustable filter coating of transmitance first, make its preparatory stage and address period transmitance extremely low, effectively reduce background light intensity, thus significantly improve contrast.

Summary of the invention

The object of the present invention is to provide a kind of method improving PDP contrast, when its PDP drives addressing to show, reduce background luminance in preparatory stage and address period; And in maintenance phase, improve exiting light beam intensity.While finally reaching the effect improving contrast, also greatly improve brightness.

The present invention is to achieve these goals by the following technical solutions:

Improve a method for PDP contrast, it is characterized in that: in the type of drive of PDP, in preparatory stage and address period, pass into voltage between horizontal electrode and vertical electrode, the transmitance of filter coating is minimum, reduces the brightness of bias light; In maintenance phase, then pass into an opposite polarity voltage, the transmitance of filter coating is the highest, and the selected cell transmitance that light is improved.

In such scheme, described filter coating comprise by glass substrate, Ne-cut/NIR-cut adhesive film, transparent substrates, the second transparency conducting layer, photochromic layer, the first transparency conducting layer, transparent substrates to lower and on the filter coating block that is superimposed as, also comprise vertical electrode and horizontal electrode, second transparency conducting layer is connected to the vertical electrode in system, and the first transparency conducting layer is connected to the horizontal electrode in system.

In such scheme, described filter coating block is formed a large filter coating with a monoblock type or is arranged in a large filter coating with array architecture, and each filter coating module unit is connected external power supply by horizontal electrode with vertical electrode.

In such scheme, the material of described photochromic layer is inorganic material or organic material; Have multiple transition metal oxide in inorganic electrochromic material, organic off-color material is oxidization-reduction type compound, metal organic compound, or conducting polymer electrochromic material.

In such scheme, described inorganic electrochromic material is one or more in Rh2O3, CoO, MoO3, V2O5, NiO, WO3, Ir2O3, TiO2, Nb2O5 electrochromic materials of being mixed to get.

In such scheme, described organic off-color material is Viologen Compounds, polyaniline, and group of the lanthanides phthaleinization is blue or green, Prussian blue, conducting polymer or polymer/metallic complex compound.

Design road of the present invention is, removes the filter coating that original transmitance is fixing, and adopt a kind of special filter coating in traditional PDP shields, and this filter coating has transmitance can the feature of fast tunable.In preparatory stage and address period, after namely passing into certain voltage, under very low-power consumption, the transmitance of filter coating just can be made very low, to reduce background luminance L _b; And in maintenance phase, pass into opposite polarity voltage, make the transmitance of filter coating very high, improve exiting light beam intensity L _d, from but contrast greatly improve.

As: traditional AC-PDP display, the transmitance of fixing filter coating is about 40%, and maximum outgoing brightness is 300 cd, and details in a play not acted out on stage, but told through dialogues brightness is 1 cd.During VGA Display form, resolution is 640 × 480, frame frequency is 60Hz, adopt ADS technology, one frame is divided 8 subfields, see Fig. 4, suppose that the time scanning a line is 3 μ s, the time scanned needed for 480 row is 1.44ms, the time that 8 sub-field scan addressing are used in a frame time 16.7ms is 11.52ms, and the time leaving sustain discharge display like this for only has 5.15ms.Visible, not displaying time L _baccount for more than 60% of a T.T..Therefore the background light level L reducing the non-maintenance phase is managed _bwill effectively raising picture contrast.Compared with the fixing filter coating being about 40% with transmitance, adopt the filtration membrane that transmitance is adjustable between 5% to 60%, contrast will improve greatly, and brightness simultaneously also improves greatly.Meanwhile, reflected light L _refalso can change along with the change of the transmitance of filter coating.In a whole field time, the non-maintenance phase is 3:2 with the time ratio of maintenance phase, and total reflecting brightness is L _ref=2cd, then the reflecting brightness L of non-maintenance phase _ref1with the reflecting brightness L of maintenance phase _ref2be respectively 1.2cd and 0.8cd.In the non-maintenance phase, when transmitance becomes 5% from 40%, L _ref10.15 cd is reduced to by 1.2 cd.In maintenance phase, transmitance becomes 60%, L from 40% _ref21.2 cd are become from 0.8cd, so, in a whole field time, total reflecting brightness L _ref`1.35 cd are dropped to by 2 original cd.

When the complete white field of display screen display, because the transmitance of filter coating brings up to 60% by 40%, make white screen brightness L _d450 cd are brought up to by 300 original cd; When display screen is in the non-maintenance phase, because the transmitance of filter coating is reduced to 5% from 40%, make background brightness L _breduce to 0.125cd, L _b1.4752 cd are reduced to by 3cd.Therefore under bright room, L _d=L _d+ L _ref=450+1.35=451.35 cd, L _b=L _b+ L _ref=1.475 cd, L contrast brings up to about 306 by original about 100:1; Light-room contrast significantly improves.

Certainly, photochromic layer can also be prepared from, as high speed electrophoresis class material, liquid crystal material etc. by except the above-mentioned material with Electrocontrolled color change function.

Accompanying drawing explanation

Fig. 1 is the structural representation of current PDP filter coating.Wherein 11 be labeled as AR layer/CH layer, 12 are labeled as PET template, and 13 are labeled as Ne-cut/NIR-cut adhesive film, and 14 are labeled as PDP shields front glass substrate.

Fig. 2 is the luminous schematic diagram of PDP.The wherein 21 brightness L being labeled as incoming ambient light _in, 22 are labeled as the reflecting brightness L of screen to surround lighting _ref, 23 are labeled as PDP shows luminosity L _d, 24 are labeled as the background luminance L under PDP details in a play not acted out on stage, but told through dialogues state _b.25 ~ 210 form the basic structure of PDP display screen, and wherein 25 is prebasal plate (being made up of 11 ~ 14 in Fig. 1), and 26 is dielectric layer, and 27 is maintenance electrode, and 28 is phosphor powder layer, and 29 is metacoxal plate, and 210 is addressing electrode.211 is gas discharge region when PDP display screen works.

Fig. 3 is the adjustable filter coating schematic diagram of PDP transmitance that the present invention adopts.Wherein 31 be labeled as transparent substrates, 32 mark transparency conducting layer 1(are connected to the horizontal electrode in system), 33 are labeled as photochromic layer, 34 are labeled as transparency conducting layer 2(is connected to vertical electrode in system), 12 are labeled as PET or other transparent substrates, 13 are labeled as Ne-cut/NIR-cut adhesive film, and 14 are labeled as PDP shields front glass substrate.

Fig. 4 is under the employing addressing of PDP is separated the type of drive of (ADS) with display, the Annual distribution of eight subfields (mark 41 ~ mark 48) and the filter coating transmitance schematic diagram of correspondence.Each subfield was made up of three time periods, be respectively the preparatory stage shown in mark 49, the address period of mark shown in 410, the maintenance phase of mark shown in 411, light grey and oblique line portion is that each subfield carries out preparation and the time shared by addressing, all subfields are all identical, Dark grey part is the time shared by sustain discharge luminescence, and its time scale is 1:2:4:8:16:32:64:128.412 are labeled as a frame time, and as 60Hz frame frequency is about 16.7ms, 50Hz frame frequency is 20ms.413 is the transmitance schematic diagram of the adjustable filter coating of transmitance, and 414 black represent light low transmission period, and its transmitance is less than 10%, and 415 whites represent light high permeability period, and its transmitance is greater than 50%.

Fig. 5 (a) and (b) are respectively side view and the vertical view of monolithic construction filter coating, and wherein 51 be labeled as substrate, 52 are labeled as transmitance real-time, tunable filter coating as shown in Figure 3, and 53 are labeled as horizontal electrode, and 54 are labeled as vertical electrode.

Fig. 6 (a) and (b) are respectively side view and the vertical view of array architecture filter coating, wherein 51 be labeled as substrate, the 62 filter coating module units being labeled as transmitance real-time, tunable as shown in Figure 3,63 are labeled as horizontal electrode array, and 64 are labeled as vertical electrode array.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described further:

First be described further design concept of the present invention, remove the filter coating that original transmitance is fixing, and adopt a kind of special filter coating in traditional PDP shields, this filter coating has transmitance can the feature of fast tunable.In preparatory stage and address period, after namely passing into certain voltage, under very low-power consumption, the transmitance of filter coating just can be made very low, to reduce background luminance L _b; And in maintenance phase, pass into opposite polarity voltage, make the transmitance of filter coating very high, improve exiting light beam intensity L _d, from but contrast greatly improve.

As: traditional AC-PDP display, the transmitance of fixing filter coating is about 40%, and maximum outgoing brightness is 300 cd, and details in a play not acted out on stage, but told through dialogues brightness is 1 cd.During VGA Display form, resolution is 640 × 480, frame frequency is 60Hz, adopt ADS technology, one frame is divided 8 subfields, see Fig. 3, suppose that the time scanning a line is 3 μ s, the time scanned needed for 480 row is 1.44ms, the time that 8 sub-field scan addressing are used in a frame time 16.7ms is 11.52ms, and the time leaving sustain discharge display like this for only has 5.15ms.Visible, not displaying time L _baccount for more than 60% of a T.T..Therefore the background light level L reducing the non-maintenance phase is managed _bwill effectively raising picture contrast.Compared with the fixing filter coating being about 40% with transmitance, adopt the filtration membrane that transmitance is adjustable between 5% to 60%, contrast will improve greatly, and brightness simultaneously also improves greatly.Meanwhile, reflected light L _refalso can change along with the change of the transmitance of filter coating.In a whole field time, the non-maintenance phase is 3:2 with the time ratio of maintenance phase, and total reflecting brightness is L _ref=2cd, then the reflecting brightness L of non-maintenance phase _ref1with the reflecting brightness L of maintenance phase _ref2be respectively 1.2cd and 0.8cd.In the non-maintenance phase, when transmitance becomes 5% from 40%, L _ref10.15 cd is reduced to by 1.2 cd.In maintenance phase, transmitance becomes 60%, L from 40% _ref21.2 cd are become from 0.8cd, so, in a whole field time, total reflecting brightness L _ref`1.35 cd are dropped to by 2 original cd.

Below in conjunction with embodiment, the present invention is described further:

Embodiment one

The electrochromism filter coating of monolithic construction

The electrochromism filter coating of monolithic construction, once prepared the large filter coating that a size enough covers whole screen, this filter coating uses structure as shown in Figure 3, the change of its transmitance is controlled by external power supply, these external power supplys are provided by two electrodes, one is horizontal electrode 53, is connected to the first transparency conducting layer 32 in Fig. 3; Another is vertical electrode 54, is connected to the second transparency conducting layer 34 in Fig. 3.In the type of drive of PDP, in preparatory stage and address period, between two electrodes, pass into certain voltage, make the transmitance of whole film minimum, to reduce the brightness of bias light; In maintenance phase, then pass into an opposite polarity voltage, the transmitance of whole film strips is the highest, and the selected cell transmitance that light is improved.By this technology, effectively contrast can be promoted.The structure of monoblock type filter coating is simple, and it is convenient to drive.

Embodiment two

The electrochromism filter coating of array architecture

The electrochromism filter coating of array architecture, multiple filter coating block is rearranged the large filter coating that a size enough covers whole screen in an orderly manner, these optical filtering film strips use the structure shown in Fig. 3, these little filter coating blocks are with array architecture arrangement (as shown in Figure 6), they share a base substrate, between film block, arrangement closely, each non-conterminous filter coating module unit has different external power supplys, these external power supplys are provided by two electrod-arrays, one is horizontal electrode array (mark 63 of Fig. 6), another is vertical electrode array (mark 64 of Fig. 6), filter coating block each is like this after passing to voltage, due to the difference of image color or extraneous light, by regulating external voltage, make the optical property of the filter coating block on screen also different.In the type of drive of PDP, in preparatory stage and address period, pass into certain voltage, make the transmitance of whole film block minimum, to reduce the brightness of bias light; In maintenance phase, pass into an opposite polarity voltage, filter coating is improved the selected cell transmitance that will light, other non-lighting unit transmitances reduce, and make transmitance keep this distribution.By this technology, its contrast is significantly promoted, the shortcoming that monolithic construction filter coating reduces in maintenance phase contrast can also be solved.The size that filter coating block does is less, and overall performance is better.

Claims

1. improve a method for PDP contrast, it is characterized in that: in the type of drive of PDP, in preparatory stage and address period, pass into voltage between horizontal electrode and vertical electrode, the transmitance of filter coating is minimum, reduces the brightness of bias light; In maintenance phase, then pass into an opposite polarity voltage, the transmitance of filter coating is the highest, and the selected cell transmitance that light is improved;

Adopt the filter coating that transmitance is adjustable between 5% to 60%, reflected light L _refalso can change along with the change of the transmitance of filter coating, in a whole field time, the non-maintenance phase is 3:2 with the time ratio of maintenance phase, and total reflecting brightness is L _ref=2cd, the reflecting brightness L of non-maintenance phase _ref1with the reflecting brightness L of maintenance phase _ref2be respectively 1.2cd and 0.8cd, in the non-maintenance phase, when transmitance becomes 5% from 40%, L _ref1be reduced to 0.15 cd by 1.2 cd, in maintenance phase, transmitance becomes 60%, L from 40% _ref21.2 cd are become from 0.8cd, in a whole field time, total reflecting brightness L _ref`1.35 cd are dropped to by 2 original cd;

When the complete white field of display screen display, because the transmitance of filter coating brings up to 60% by 40%, make white screen brightness L _d450 cd are brought up to by 300 original cd; When display screen is in the non-maintenance phase, because the transmitance of filter coating is reduced to 5% from 40%, make background brightness L _breduce to 0.125cd, L _b1.4752 cd are reduced to by 3cd, under bright room, L _d=L _d+ L _ref=450+1.35=451.35 cd, L _b=L _b+ L _ref=1.475 cd, L _dfor the brightness that display screen shields entirely in vain, L _bfor details in a play not acted out on stage, but told through dialogues brightness, L _dfor display screen white brightness.

2. improve the method for PDP contrast according to claim 1, it is characterized in that: filter coating comprise by glass substrate, Ne-cut/NIR-cut adhesive film, transparent substrates, the second transparency conducting layer, photochromic layer, the first transparency conducting layer, transparent substrates to lower and on the filter coating block that is superimposed as, also comprise vertical electrode and horizontal electrode, second transparency conducting layer is connected to the vertical electrode in system, and the first transparency conducting layer is connected to the horizontal electrode in system.

3. according to claim 1 or 2, improve the method for PDP contrast, it is characterized in that: described filter coating block is formed a large filter coating with a monoblock type or is arranged in a large filter coating with array architecture, and each filter coating module unit is connected external power supply by horizontal electrode with vertical electrode.

4. the method for raising PDP contrast according to claim 2, is characterized in that: the material of described photochromic layer is inorganic electrochromic material or organic off-color material; Have transition metal oxide in inorganic electrochromic material, organic off-color material is oxidization-reduction type compound, metal organic compound, or conducting polymer electrochromic material.

5. the method for raising PDP contrast according to claim 4, is characterized in that: described inorganic electrochromic material is one or more in Rh2O3, CoO, MoO3, V2O5, NiO, WO3, Ir2O3, TiO2, Nb2O5 electrochromic materials of being mixed to get.

6. the method for raising PDP contrast according to claim 4, is characterized in that: described organic off-color material is blue or green, the Prussian blue or polymer/metallic complex compound of Viologen Compounds, polyaniline, group of the lanthanides phthaleinization.