Patent Grant
9785012
1. Field of the Invention
The present invention relates to the field of displaying technology, and in particular to a high transmittance PSVA (Polymer Stabilized Vertical Alignment) liquid crystal display panel and a manufacturing method thereof.
2. The Related Arts
Active thin-film transistor liquid crystal displays (TFT-LCDs) have been recently developed swiftly and have had wide applications recently. Mainstream TFT-LCDs currently available in the market belong to three categories, which are respectively twisted nematic (TN) or super twisted nematic (STN) type, in-plane switching (IPS) type, and vertical alignment (VA) type. Among them, VA type liquid crystal displays have extremely high contrast as compared to other types and may generally reach 4000-8000. This provides extremely wide applications in large-sized displays, such as televisions.
The reason that the VA type liquid crystal displays have the extremely high contrast is because liquid crystal molecules are arranged perpendicular to a surface of a substrate and have no phase difference in a dark state where no electricity is applied so as to have extremely low leakage of light and very low dark state brightness. According to contrast calculation equation, the lower the dark state brightness is, the higher the contrast will be. To allow the liquid crystal molecules in a VA type liquid crystal display panel to be arranged perpendicular to the surface of the substrate, the liquid crystal molecules must be subjected to alignment, of which the most common way is to coat a vertical alignment agent (which is a polymer material of polyimide (PI), a PI solution) on specific areas of upper and lower substrates and then the substrates are baked for a long time in a predetermined temperature to dry a solvent of the alignment agent thereby forming a PI alignment layer on the surfaces of the substrates. As shown in
To provide a VA type liquid crystal display panel with bettered characteristics in wide view angles and to improve the issue of color shift, multi-domain VA (MVA) technology is often adopted, in which a sub-pixel is divided into multiple zones and the liquid crystal of each zone is caused to tilt in different direction when a voltage is applied so that the result of viewing from different angles would approach homogeneity and consistency. Various ways may be used to provide the MVA technology. As shown in
With the progress of technology, a kind of MVA type liquid crystal display panel that requires no PI alignment layer is available and is referred to as a polymer stabilized vertical alignment (PSVA) liquid crystal display panel. As shown in
Since the pixel electrode 400 that is processed to form a star-shaped pattern comprise a pattern that comprises pixel electrode branches that extend in various directions and alternate with the slits, the electric field formed thereby with respect to the opposite common electrode 300 is not uniform, the electric field corresponding to an area of the pixel electrode branch is apparently stronger than the electric field corresponding to an area of the slit thereby leading to a phenomenon of non-uniform brightness occurring in the pixel.
Further, according to the transmittance equation of the VA type liquid crystal display panel:
T=(½)sin22Δφ sin2(Γ/2) (1)
where T is transmittance; Δφ is an included angle between a long axis of liquid crystal and a polarizer, which provides the maximum efficiency at 45°; Γ is phase difference, which is the effect of modulation of the rotation of liquid crystal molecules with respect to polarization light under an electric field.
The formula for Γ is as follows:
Γ=cos(a)*2π*Δn*d/λ (2)
where a is an included angle between the long axis of liquid crystal molecule and a normal of a substrate, which is determined by the electric field applied to the liquid crystal molecules; d is thickness of a liquid crystal cell; and Δn is refractive index difference between long and short axes of the liquid crystal.
It can be known from equation (1) that when Γ is π, the transmittance is maximum. Combining equation (1) with equation (2) provides that with the liquid crystal cell thickness d being fixed, the transmittance is determined by the electric field applied to the liquid crystal. When Γ is smaller than π, the greater the electric field is, the greater the transmittance would be; and when Γ is greater than π, the greater the electric field is, the smaller the transmittance would be.
Since the electric fields associated with the areas corresponding to the pixel electrode branches and the slits are not consistent, it is generally not possible to make the transmittance of these two areas simultaneously reach the maximum value. In other words, when Γ of the pixel electrode branch is π, the value of Γ of the area corresponding to the slit is smaller than π; and when the value of Γ of the area corresponding to the slit reaches π, the value of Γ of the area associated with the pixel electrode branch has already exceeded π. Thus, the entire pixel area cannot simultaneously reach the maximum transmittance and thus, it is not possible to achieve the maximum transmittance of a liquid crystal display panel and the brightness of the liquid crystal display panel is non-uniform.
An object of the present invention is to provide a high transmittance polymer stabilized vertical alignment (PSVA) liquid crystal display panel, which allows the entire pixel area to simultaneously achieve the maximum transmittance so as to overcome the issue of transmittance reduction of the prior art due to patternization of the pixel electrode and helping improve homogeneity of transmittance and brightness of the PSVA liquid crystal display panel, reducing the requirement of backlighting brightness by the PSVA liquid crystal display panel, and lowering down cost and power consumption of use
An object of the present invention is also to provide a manufacturing method of a high transmittance PSVA liquid crystal display panel, wherein a PSVA liquid crystal display panel manufactured with the method has high transmittance and uniform brightness, reduces the requirement of backlighting brightness by the PSVA liquid crystal display panel, and lowers down cost and power consumption of use.
To achieve the above objects, the present invention provides a high transmittance PSVA liquid crystal display panel, which comprises an upper substrate and a lower substrate that is opposite to the upper substrate, a first common electrode, an insulation layer, and a second common electrode that are arranged to stack, in sequence from top to bottom, on a surface of the upper substrate that faces the lower substrate, a pixel electrode that is arranged on a surface of the lower substrate that faces the upper substrate, a liquid crystal layer interposed between the second common electrode and the pixel electrode, and a plurality of polymer projections formed on surfaces of the second common electrode and the pixel electrode;
one of the first common electrode and the second common electrode being a patternized common electrode, which corresponds to each of sub-pixels, the patternized common electrode being divided into a plurality of zones and each zone comprising a pattern comprising common electrode branches extending in various directions and alternating with spacing slits; and the other one being a planar common electrode that has a uniform thickness and is continuous without interruption;
the pixel electrode being a planar electrode that has a uniform thickness and is continuous without interruption;
the polymer projections align liquid crystal molecules contained in the liquid crystal layer so as to set the liquid crystal molecules at predetermined pre-tilt angles;
wherein in a manufacturing process of the high transmittance PSVA liquid crystal display panel, a voltage is applied to the pixel electrode and the patternized common electrode; and in a use of the high transmittance PSVA liquid crystal display panel, a voltage is applied to the pixel electrode and the planar common electrode.
The first common electrode is the planar common electrode and the second common electrode is the patternized common electrode; in the manufacturing process of the high transmittance PSVA liquid crystal display panel, the voltage is applied to the pixel electrode and the second common electrode; in the use of the high transmittance PSVA liquid crystal display panel, the voltage is applied to the pixel electrode and the first common electrode.
The second common electrode is the planar common electrode and the first common electrode is the patternized common electrode; in the manufacturing process of the high transmittance PSVA liquid crystal display panel, the voltage is applied to the pixel electrode and the first common electrode; in the use of the high transmittance PSVA liquid crystal display panel, the voltage is applied to the pixel electrode and the second common electrode.
The patternized common electrode comprises a star-shaped pattern.
The first common electrode, the second common electrode, and the pixel electrode comprise a material of indium tin oxide (ITO); and
the insulation layer comprises a material of silicon nitride or silicon oxide.
The polymer projections are formed through polymerization of the polymerizable monomers caused by irradiation of ultraviolet (UV) light.
The polymerizable monomers comprise one of acrylate ester and derivatives thereof, methacrylate ester and derivatives thereof, styrene and derivatives thereof, epoxy rein and fatty amine epoxy curing agent, or a combination thereof.
The present invention also provides a manufacturing method of a high transmittance PSVA liquid crystal display panel, which comprises the following steps:
(1) providing an upper substrate and a lower substrate,
wherein a first common electrode, an insulation layer covering the first common electrode, and a second common electrode located on the insulation layer are first formed in sequence on the upper substrate, one of the first common electrode and the second common electrode being a patternized common electrode, which corresponds to each of sub-pixels, the patternized common electrode being divided into a plurality of zones and each zone comprising a pattern comprising common electrode branches extending in various directions and alternating with spacing slits; and the other one being a planar common electrode that has a uniform thickness and is continuous without interruption;
a pixel electrode is formed on the lower substrate and the pixel electrode is a planar electrode that has a uniform thickness and is continuous without interruption; and
the upper and lower substrates are then laminated together and a mixture of liquid crystal molecules and polymerizable monomers is filled between the second common electrode and the pixel electrode;
(2) applying a voltage to the pixel electrode and the patternized common electrode to cause the liquid crystal molecules to tilt in various directions along spacing slits so as to form multiple domains in each of the sub-pixels; and
(3) in the same time of applying a voltage to the pixel electrode and the patternized common electrode, applying UV light irradiation to cause polymerization of the polymerizable monomers to form polymer projections attached to surfaces of the pixel electrode and the second common electrode for aligning the liquid crystal molecules contained in a liquid crystal layer thereby setting the liquid crystal molecules at predetermined pre-tilt angles.
The patternized common electrode comprises a star-shaped pattern; the first common electrode, the second common electrode, and the pixel electrode comprises a material of ITO; the insulation layer comprises a material of silicon nitride or silicon oxide.
The polymerizable monomers comprise one of acrylate ester and derivatives thereof, methacrylate ester and derivatives thereof, styrene and derivatives thereof, epoxy rein and fatty amine epoxy curing agent, or a combination thereof.
The present invention further provides a high transmittance PSVA liquid crystal display panel, which comprises an upper substrate and a lower substrate that is opposite to the upper substrate, a first common electrode, an insulation layer, and a second common electrode that are arranged to stack, in sequence from top to bottom, on a surface of the upper substrate that faces the lower substrate, a pixel electrode that is arranged on a surface of the lower substrate that faces the upper substrate, a liquid crystal layer interposed between the second common electrode and the pixel electrode, and a plurality of polymer projections formed on surfaces of the second common electrode and the pixel electrode;
one of the first common electrode and the second common electrode being a patternized common electrode, which corresponds to each of sub-pixels, the patternized common electrode being divided into a plurality of zones and each zone comprising a pattern comprising common electrode branches extending in various directions and alternating with spacing slits; and the other one being a planar common electrode that has a uniform thickness and is continuous without interruption;
the pixel electrode being a planar electrode that has a uniform thickness and is continuous without interruption;
the polymer projections align liquid crystal molecules contained in the liquid crystal layer so as to set the liquid crystal molecules at predetermined pre-tilt angles;
wherein in a manufacturing process of the high transmittance PSVA liquid crystal display panel, a voltage is applied to the pixel electrode and the patternized common electrode; and in a use of the high transmittance PSVA liquid crystal display panel, a voltage is applied to the pixel electrode and the planar common electrode;
wherein the first common electrode is the planar common electrode and the second common electrode is the patternized common electrode; in the manufacturing process of the high transmittance PSVA liquid crystal display panel, the voltage is applied to the pixel electrode and the second common electrode; in the use of the high transmittance PSVA liquid crystal display panel, the voltage is applied to the pixel electrode and the first common electrode;
wherein the patternized common electrode comprises a star-shaped pattern; and
wherein the polymer projections are formed through polymerization of the polymerizable monomers caused by irradiation of UV light.
The efficacy of the present invention is that the present invention provides a high transmittance PSVA liquid crystal display panel, which comprises an upper substrate on which a first common electrode, an insulation layer, and a second common electrode are formed, a lower substrate on which a pixel electrode is formed, and a plurality of polymer projections formed on surfaces of the second common electrode and the pixel electrode to align liquid crystal molecules, wherein one of the first common electrode and the second common electrode is a patternized common electrode corresponding to each of sub-pixels, the patternized common electrode being divided into a plurality of zones, each zone comprising a pattern comprising common electrode branches extending in various directions and alternating with spacing slits; while the other one is a planar common electrode that has a uniform thickness and is continuous without interruption and wherein the pixel electrode is a planar electrode that has a uniform thickness and is continuous without interruption. In a manufacturing process of the high transmittance PSVA liquid crystal display panel, a voltage is applied to the pixel electrode and the patternized common electrode to cause the liquid crystal molecules to tilt in various directions along spacing slits so as to form multiple domains in each sub-pixel; and in a user of the high transmittance PSVA liquid crystal display panel, through application of a voltage to the pixel electrode and the planar common electrode, the entire pixel area may simultaneously achieve the maximum transmittance, thereby overcoming the issue of transmittance reduction of the prior art due to patternization of the pixel electrode and helping improve homogeneity of transmittance and brightness of the PSVA liquid crystal display panel, reducing the requirement of backlighting brightness by the PSVA liquid crystal display panel, and lowering down cost and power consumption of use. The present invention provides a manufacturing method of a high transmittance PSVA liquid crystal display panel, in which a first common electrode, an insulation layer, and a second common electrode are formed on an upper substrate and a pixel electrode is formed on the lower substrate, wherein one of the first common electrode and the second common electrode is a patternized common electrode and the other is a planar common electrode, the pixel electrode being a planar electrode, whereby through irradiation of UV light to cause polymerization of polymerizable monomers to form polymer projections that align the liquid crystal molecules so as to make the transmittance of the PSVA liquid crystal display panel high, the brightness homogeneous, the requirement of backlighting brightness by the PSVA liquid crystal display panel being reduced, and cost and power consumption of use being lowered.
For better understanding of the features and technical contents of the present invention, reference will be made to the following detailed description of the present invention and the attached drawings. However, the drawings are provided for the purposes of reference and illustration and are not intended to impose limitations to the present invention.
The technical solution, as well as other beneficial advantages, of the present invention will be apparent from the following detailed description of an embodiment of the present invention, with reference to the attached drawing.
In the drawing:
To further expound the technical solution adopted in the present invention and the advantages thereof, a detailed description is given to a preferred embodiment of the present invention and the attached drawings.
Referring collectively to
One of the first common electrode 31 and the second common electrode 33 is a patternized common electrode, which corresponds to each of sub-pixels, the patternized common electrode being divided into a plurality of zones and each zone comprising a pattern comprising common electrode branches extending in various directions and alternating with spacing slits; and the other one is a planar common electrode that has a uniform thickness and is continuous without interruption.
The pixel electrode 4 is a planar electrode that has a uniform thickness and is continuous without interruption.
The polymer projections 5 function to align liquid crystal molecules 7 contained in the liquid crystal layer so as to set the liquid crystal molecules 7 at predetermined pre-tilt angles.
The patternized common electrode provides an effect in a manufacturing process of the high transmittance PSVA liquid crystal display panel, while the planar common electrode provides an effect in a use of the high transmittance PSVA liquid crystal display panel.
Considering the example that the first common electrode 31 is the planar common electrode and the second common electrode 33 is the patternized common electrode, in the manufacturing process of the high transmittance PSVA liquid crystal display panel, application of a voltage to the pixel electrode 4 and the second common electrode 33 allows an inclined electric field to be established between the pixel electrode 4 and the second common electrode 33 so that the liquid crystal molecules 7 tilt in various directions of the spacing slits so as to form multiple zones in each sub-pixel, this, in combination with subsequent irradiation of ultraviolet (UV) light to cause polymerization of polymerizable monomers to form the polymer projections 5, providing the liquid crystal molecules 7 with predetermined pre-tilt angle. In the use of the high transmittance PSVA liquid crystal display panel, as shown in
Of course, if the second common electrode 33 is used as the planar common electrode, while the first common electrode 31 is the patternized common electrode, then in the manufacturing process of the high transmittance PSVA liquid crystal display panel, voltage application is done on the pixel electrode 4 and the first common electrode 31; and in the use of the high transmittance PSVA liquid crystal display panel, voltage application is done on the pixel electrode 4 and the second common electrode 33.
Specifically, the upper substrate 1 is generally a color filter (CF) substrate that is conventionally used, and the lower substrate 2 is generally a thin-film transistor (TFT) substrate that is commonly used.
As shown in
The first common electrode 31, the second common electrode 33, and the pixel electrode 4 each comprise a material of indium tin oxide (ITO).
The insulation layer 32 comprises a material of silicon nitride or silicon oxide.
The polymerizable monomers comprise one of acrylate ester and derivatives thereof, methacrylate ester and derivatives thereof, styrene and derivatives thereof, epoxy rein, and fatty amine epoxy curing agent, or a combination thereof.
Referring to
Step 1: as shown in
A first common electrode 31, an insulation layer 32 covering the first common electrode 31, and a second common electrode 33 located on the insulation layer 32 are first formed in sequence on the upper substrate 1. One of the first common electrode 31 and the second common electrode 33 is a patternized common electrode, which corresponds to each of sub-pixels, the patternized common electrode being divided into a plurality of zones and each zone comprising a pattern comprising common electrode branches extending in various directions and alternating with spacing slits; and the other one is a planar common electrode that has a uniform thickness and is continuous without interruption. A pixel electrode 4 is formed on the lower substrate 2 and the pixel electrode 4 is a planar electrode that has a uniform thickness and is continuous without interruption.
The upper and lower substrates 1, 2 are then laminated together and a mixture of liquid crystal molecules 7 and polymerizable monomers 5′ is filled between the second common electrode 33 and the pixel electrode 4.
Step 2: applying a voltage to the pixel electrode 4 and the patternized common electrode to cause the liquid crystal molecules 7 to tilt in various directions along spacing slits so as to form multiple domains in each of sub-pixels.
Step 3: as shown in
To this point, the manufacturing of the high transmittance PSVA liquid crystal display panel is completed.
Specifically, the patternized common electrode comprises a star like pattern and the first common electrode 31, the second common electrode 33, and the pixel electrode 4 comprises a material of ITO; the insulation layer 32 comprises a material of silicon nitride or silicon oxide.
As shown in
In summary, the present invention provides a high transmittance PSVA liquid crystal display panel, which comprises an upper substrate on which a first common electrode, an insulation layer, and a second common electrode are formed, a lower substrate on which a pixel electrode is formed, and a plurality of polymer projections formed on surfaces of the second common electrode and the pixel electrode to align liquid crystal molecules, wherein one of the first common electrode and the second common electrode is a patternized common electrode corresponding to each of sub-pixels, the patternized common electrode being divided into a plurality of zones, each zone comprising a pattern comprising common electrode branches extending in various directions and alternating with spacing slits; while the other one is a planar common electrode that has a uniform thickness and is continuous without interruption and wherein the pixel electrode is a planar electrode that has a uniform thickness and is continuous without interruption. In a manufacturing process of the high transmittance PSVA liquid crystal display panel, a voltage is applied to the pixel electrode and the patternized common electrode to cause the liquid crystal molecules to tilt in various directions along spacing slits so as to form multiple domains in each sub-pixel; and in a user of the high transmittance PSVA liquid crystal display panel, through application of a voltage to the pixel electrode and the planar common electrode, the entire pixel area may simultaneously achieve the maximum transmittance, thereby overcoming the issue of transmittance reduction of the prior art due to patternization of the pixel electrode and helping improve homogeneity of transmittance and brightness of the PSVA liquid crystal display panel, reducing the requirement of backlighting brightness by the PSVA liquid crystal display panel, and lowering down cost and power consumption of use. The present invention provides a manufacturing method of a high transmittance PSVA liquid crystal display panel, in which a first common electrode, an insulation layer, and a second common electrode are formed on an upper substrate and a pixel electrode is formed on the lower substrate, wherein one of the first common electrode and the second common electrode is a patternized common electrode and the other is a planar common electrode, the pixel electrode being a planar electrode, whereby through irradiation of UV light to cause polymerization of polymerizable monomers to form polymer projections that align the liquid crystal molecules so as to make the transmittance of the PSVA liquid crystal display panel high, the brightness homogeneous, the requirement of backlighting brightness by the PSVA liquid crystal display panel being reduced, and cost and power consumption of use being lowered.
Based on the description given above, those having ordinary skills of the art may easily contemplate various changes and modifications of the technical solution and technical ideas of the present invention and all these changes and modifications are considered within the protection scope of right for the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015 1 0208473 | Apr 2015 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2015/082164 | 6/24/2015 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2016/173109 | 11/3/2016 | WO | A |
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| 101762914 | Jun 2010 | CN |
| Number | Date | Country | |
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| 20170139278 A1 | May 2017 | US |
