CN100338512C - Polarizers for Multi-domain Vertical Alignment Liquid Crystal Displays - Google Patents

Abstract

A polarizing plate for a liquid crystal display is composed of two parts. The first part of the polarizing plate is adjacent to the backlight source, and the backlight source and the multi-domain vertical alignment liquid crystal layer sequentially comprise a protective film, a linear polarizing film, a biaxial stretching film and a quarter-wavelength phase difference film. The second part of the polarizer is positioned at the other side of the multi-domain vertical alignment liquid crystal layer, and comprises a quarter-wavelength phase difference film, a biaxial extension film, a linear polarization film and a protective film in sequence from the multi-domain vertical alignment liquid crystal layer.

Description

Polarizers for Multi-domain Vertical Alignment Liquid Crystal Displays

(1) Technical field

The invention relates to a liquid crystal display device, and in particular to a polarizing plate of a multi-domain vertical alignment liquid crystal display.

(2) Background technology

Liquid crystal displays have the advantages of high image quality, small size, light weight, low voltage drive, low power consumption, and wide application range. Therefore, it is widely used in consumer electronics or computer products such as medium and small portable TVs, mobile phones, video recorders, notebook computers, desktop monitors, and projection TVs, and has gradually replaced cathode ray tubes. , CRT) has become the mainstream of the display. In recent years, the liquid crystal display market has increased greatly, especially in the application of computers and notebook computers. The so-called requirements of large area, high resolution, wide viewing angle and fast response time have also become the key to the requirements of these liquid crystal displays.

Multi-domain vertical alignment (MVA) is a widely used wide viewing angle technology. Segmentation technology constitutes. In this type of multi-domain vertically aligned liquid crystal display, it is necessary to manufacture some structures inside the two substrates of the liquid crystal display, use these structures to form different regions, and arrange the liquid crystal molecules in each region in different directions to achieve wide function of perspective.

FIG. 1A is a schematic diagram of a conventional multi-domain vertical alignment liquid crystal panel. The liquid crystal pixel 102 in charge of displaying red in FIG. There are liquid crystal molecules 122 , 124 , 126 , and 128 aligned in different directions, respectively. FIG. 1B is a schematic diagram of alignment directions of liquid crystal molecules in different regions in FIG. 1A . As shown in FIG. 1B , in the four regions, the liquid crystal molecules 122 , 124 , 126 and 128 are arranged in different directions, so as to achieve the function of wide viewing angle.

Generally speaking, the multi-domain vertical alignment technology provides at least four alignment regions in a single pixel, enabling it to achieve wide-angle properties in at least four directions. For the viewing angle characteristics of the alignment division of the four alignment regions, its oblique 45-degree angle direction characteristics are poor, but as long as it is compensated with an optical compensation film, such as a biaxial film (biaxial film), better results can be obtained. viewing angle characteristics.

However, in addition to the oblique 45-degree viewing angle characteristics, the multi-domain vertical alignment technology also has the problem of insufficient brightness. First of all, since the multi-domain vertical alignment technology is to form multiple structures on the panel to divide the alignment area and align the liquid crystal molecules, these structures will inevitably reduce the aperture ratio of the panel. The aperture ratio of the panel is related to the brightness of the liquid crystal display, and the larger the aperture ratio of the panel, the greater the brightness of the liquid crystal display. Therefore, these structures used in the multi-domain vertical alignment technology often reduce the brightness of the liquid crystal display, resulting in insufficient brightness.

In addition, the vertically aligned liquid crystal molecules are vertically aligned in the off state (off state), and their arrangement is perpendicular to the liquid crystal panel to present a dark state. In the on state (on state), it will be affected by the electric field and turn into a horizontal alignment. Its arrangement is parallel to the upper and lower substrates, but not parallel to any absorption axis of the upper or lower linear polarizing film, so as to present a bright light. state. In this configuration, when two adjacent liquid crystal molecules fall due to the influence of the electric field, they often collide because their positions are too close. Moreover, under the continuous influence of the electric field, the two liquid crystal molecules have to continue to tilt in a direction parallel to the absorption axis of the upper or lower linear polarizing film, and finally the arrangement of the two liquid crystal molecules will be parallel to the upper or lower linear polarizing film. the absorption axis.

Therefore, in this kind of liquid crystal pixel, when the liquid crystal molecules at the junction of each alignment region are in the on state, because their alignment direction is parallel to the above-mentioned absorption axis, the liquid crystal pixel operating in the bright state, its middle position But it presents a dark pattern similar to a cross. This dark cross pattern will reduce the luminance of the liquid crystal display in the bright state, and since the contrast is generally defined as the ratio of the luminance of the bright state to the luminance of the dark state, the above dark cross pattern will also reduce the contrast of the liquid crystal display, resulting in The brightness and contrast of the liquid crystal display are insufficient.

The conventional multi-domain vertical alignment liquid crystal display has the above problems of insufficient brightness and contrast. Therefore, in order to maintain the high brightness and high contrast of the liquid crystal display, when designing and manufacturing the liquid crystal display, more lamps are usually used in its backlight Tube. However, if the number of backlight tubes used in the liquid crystal display is larger, the power required for its operation is relatively higher, and the heat generated accordingly is also higher. The high power consumption demand will reduce the working hours of portable electronic devices that widely use liquid crystal displays, such as notebook computers or personal digital assistants, and it is not conducive to carry-on operation. Moreover, excess heat will often increase the heat dissipation burden of the liquid crystal display, and accelerate the loss of its backlight tube, reducing the service life of the backlight tube.

(3) Contents of the invention

Therefore, the object of the present invention is to provide a polarizer for a vertical alignment liquid crystal display, which is used to increase the brightness of the vertical alignment liquid crystal display, and improve the high power consumption and high heat generation problems of the conventional vertical alignment display.

Another object of the present invention is to provide a polarizing plate for a multi-domain vertically aligned liquid crystal display, which can improve the utilization rate of light by using the added quarter-wavelength retardation film, increase the brightness of the liquid crystal display in the bright state, and effectively Reduce the loss of its backlight tube.

According to the above object of the present invention, a polarizer for a multi-domain vertical alignment liquid crystal display is proposed. The first part of the polarizing plate is adjacent to the backlight source. From the backlight source to the multi-domain vertical alignment liquid crystal layer, it includes a protective film, a linear polarizing film, a biaxially stretched film and a quarter-wave retardation film. The second part of the polarizing plate is located on the other side of the multi-domain vertical alignment liquid crystal layer. The multi-domain vertical alignment liquid crystal layer includes a quarter-wavelength retardation film, a biaxially stretched film, a linear polarizing film and a protective film in sequence. film.

The above two parts are used to form a polarizing plate for multi-domain vertical alignment liquid crystal displays. The quarter-wavelength retardation film can convert the original linearly polarized light into circularly polarized light, and use the characteristics of circularly polarized light to eliminate the conventional To improve the brightness of the multi-domain vertical alignment liquid crystal display, thereby reducing its power demand and the loss of the backlight lamp tube.

In the polarizing plate of the present invention, the absorption axes of the two linear polarizing films must be perpendicular to each other so as to cooperate with each other to control the brightness and darkness of the pixels of the liquid crystal display during operation. In addition, the slow axes (slow axes) of the two quarter-wavelength retardation films must also be perpendicular to each other, so that after the linearly polarized light is converted into circularly polarized light or elliptically polarized light by the first quarter-wavelength retardation film, Can be fully reconverted back to linearly polarized light by the second quarter-wave retardation film.

Since the wavelength of visible light ranges from 400nm to 700nm, the center wavelength of the above-mentioned quarter-wavelength retardation film is generally selected to be between 480nm and 600nm to achieve the best use effect. In addition, the present invention also provides a broad band quarter-wavelength retardation film, so that the polarizing plate of the present invention can be well compensated in the entire visible light wavelength range from 400nm to 700nm.

According to a preferred embodiment of the present invention, the light passes through the protective film, the linear polarizing film, the biaxially stretched film, the quarter-wave retardation film, the multi-domain vertical alignment liquid crystal layer, and the quarter-wavelength polarizing film from the backlight in sequence. Phase difference films, biaxially stretched films, linear polarizing films, and protective films.

According to another preferred embodiment of the present invention, the light from the backlight passes through the protective film, the linear polarizing film, the quarter-wave retardation film, the biaxially stretched film, the multi-domain vertical alignment liquid crystal layer, and the biaxially stretched film. , quarter-wave retardation film, linear polarizing film and protective film.

According to another preferred embodiment of the present invention, when the angle between the absorption axis of the linearly stretched film and the slow axis of the quarter-wavelength retardation film is 45 degrees, the quarter-wavelength retardation film can Linearly polarized light is converted into circularly polarized light, that is, the polarization direction of light will be uniformly distributed in all directions over time, and the compensation effect of the polarizer is the best at this time. In addition, when the slow axes of the two biaxially stretched films in the present invention are perpendicular to each other, and the slow axes of each biaxially stretched film are also perpendicular to the absorption axes of its adjacent linear polarizing films, the optimum The viewing angle compensation effect.

According to yet another preferred embodiment of the present invention, a half-wavelength retardation film and a quarter-wavelength retardation film are combined to obtain a polarization phase effect equivalent to a broadband quarter-wavelength retardation film . When using this wide-band quarter-wavelength retardation film, the angle between the slow axis of the half-wavelength retardation film and the absorption axis of its adjacent linear polarizing film has an angle range of between Between 0 and 40 degrees. The angle between the slow axis of the quarter-wave retardation film and the absorption axis of the adjacent linear polarizing film ranges from 50 to 85 degrees.

The present invention uses a quarter-wavelength retardation film to convert the linearly polarized light originally entering the multi-domain vertically aligned liquid crystal layer into circularly polarized light, so as to avoid the linearly polarized light in a single direction being directed parallel to the upper or lower linearly polarized light Due to the influence of liquid crystal molecules tilted in the direction of the absorption axis of the film, dark cross lines appear in the middle of the liquid crystal pixel. Therefore, the present invention can effectively improve the utilization rate of light, increase the brightness of the liquid crystal display in the bright state, and prolong the service life of the backlight lamp tube.

(4) Description of drawings

In order to make the above and other purposes, features and advantages of the present invention more comprehensible, a preferred embodiment is specifically cited below, and is described in detail in conjunction with the accompanying drawings as follows:

FIG. 1A is a schematic diagram of a conventional multi-domain vertical alignment liquid crystal panel.

FIG. 1B is a schematic diagram of the alignment direction of liquid crystal molecules in FIG. 1A .

FIG. 2A is a schematic diagram of a preferred embodiment of the present invention.

Fig. 2B is a schematic diagram of another preferred embodiment of the present invention.

3A is a schematic diagram of the relationship between the absorption axis of the linearly stretched film and the slow axis of the quarter-wave retardation film of the present invention.

3B is a schematic diagram of the relationship between the absorption axis of the linearly stretched film and the slow axis of the quarter-wave retardation film of the present invention.

Fig. 4 is a schematic diagram showing the relationship between the absorption axis of the linearly stretched film and the slow axis of the biaxially stretched film of the present invention.

Fig. 5A is a schematic diagram of another preferred embodiment of the present invention.

FIG. 5B is a schematic diagram of another preferred embodiment of the present invention.

(5) specific implementation

In order to improve the problems of high power consumption and high heat generation of the conventional multi-domain vertical alignment display, the present invention proposes a polarizer for the multi-domain vertical alignment liquid crystal display.

The polarizing plate of the multi-domain vertical alignment liquid crystal display of the present invention is composed of two parts. The first part of the polarizing plate is adjacent to the backlight source. From the backlight source to the multi-domain vertical alignment liquid crystal layer, it includes a protective film, a linear polarizing film, a biaxially stretched film and a quarter-wave retardation film. The second part of the polarizing plate is located on the other side of the multi-domain vertical alignment liquid crystal layer. The multi-domain vertical alignment liquid crystal layer includes a quarter-wavelength retardation film, a biaxially stretched film, a linear polarizing film and a protective film in sequence. film.

Using the above two parts to form a polarizing plate for multi-domain vertical alignment liquid crystal display, the quarter-wave retardation film can convert the original linearly polarized light into circularly polarized light, and use the characteristics of circularly polarized light to eliminate the conventional To improve the brightness of the multi-domain vertical alignment liquid crystal display, thereby reducing its power demand and the loss of the backlight lamp tube.

In the polarizing plate of the present invention, the absorption axes of the two linear polarizing films must be perpendicular to each other, so as to cooperate with each other to control the brightness and darkness of the pixels of the liquid crystal display during operation. In addition, the slow axes of the two quarter-wavelength retardation films must also be perpendicular to each other, so that the linearly polarized light can be completely absorbed by the second surface after being converted into circularly polarized light by the first quarter-wavelength retardation film. The quarter-wave retardation film then converts back to linearly polarized light.

Since the wavelength of visible light ranges from 400nm to 700nm, the center wavelength of the above-mentioned quarter-wavelength retardation film is usually selected around 550nm to achieve the best use effect. In addition, the present invention also provides a broad band quarter-wavelength retardation film, so that the polarizing plate of the present invention can be well compensated in the entire visible light wavelength range from 400nm to 700nm.

FIG. 2A is a schematic diagram of a preferred embodiment of the present invention. In this preferred embodiment, the polarizer of the multi-domain vertical alignment liquid crystal display of the present invention is composed of two polarizer parts 202a and 204a. The polarizer part 202a is adjacent to the backlight, and includes a protective film 212 , a linear polarizing film 214 , a biaxially stretched film 216 and a quarter-wave retardation film 218 from the backlight to the MVA liquid crystal layer 206 in sequence. The other polarizer part 204a is located on the other side of the multi-domain vertical alignment liquid crystal layer 206, and the multi-domain vertical alignment liquid crystal layer 206 includes a quarter-wave retardation film 228, a biaxially stretched film 226, a linear Polarizing film 224 and protective film 222 .

The polarizing plate of the present invention uses the quarter-wave retardation film 218 to convert the linearly polarized light screened by the linear polarizing film 214 and ready to enter the multi-domain vertical alignment liquid crystal layer 206 into circularly polarized light. Since the circularly polarized light will not be affected by the liquid crystal molecules located at the junction of two adjacent alignment regions and parallel to the absorption axis of the upper or lower substrate, the conventional dark cross fringe problem can be eliminated. Then, the circularly polarized light is converted back to Polarized light is used for screening by the linear polarizing film 224 .

In addition, in the present invention, the positions of the biaxially stretched film and the quarter-wave retardation film in the two polarizing plate parts 202a and 204a can be interchanged together, and are not limited by the arrangement in the embodiment shown in FIG. 2A . However, it should be noted that after the swapping, the sequence must still be arranged symmetrically with the multi-domain vertical alignment liquid crystal layer 206 as the center, so as to obtain a complete compensation effect.

Fig. 2B is a schematic diagram of another preferred embodiment of the present invention. The positions between the biaxially stretched film 216 and the quarter-wave retardation film 218 in the polarizer part 202b are exchanged, and the biaxially stretched film 226 and the quarter-wave retardation film 226 in the other polarizer part 204b are reversed. The positions between films 228 are also interchanged.

The light passes through the protective film 212, linear polarizing film 214, quarter-wavelength retardation film 218, biaxially stretched film 216, multi-domain vertical alignment liquid crystal layer 206, biaxially stretched film 226, quarter The wavelength retardation film 228 , the linear polarizing film 224 and the protective film 222 . In this way, the polarizing plate in FIG. 2B can also obtain the same effect as the polarizing plate in FIG. 2A .

The characteristics of the two linear polarizing films used in the present invention are the same as the two linear polarizing films in the known liquid crystal display, that is to say, the absorption axes of the upper and lower two linear polarizing films must be perpendicular to each other, so as to realize the control of the bright state of the liquid crystal pixels or dark state functionality. Moreover, the slow axes of the two quarter-wavelength retardation films in the present invention must also be perpendicular to each other, so that the linearly polarized light is converted into circularly polarized light or elliptically polarized light by the first quarter-wavelength retardation film. , can be completely converted back to linearly polarized light by the second quarter-wavelength retardation film.

Taking the embodiment of FIG. 2A as an example, the above-mentioned conversion process of the light polarization direction will be described below. First, the light from the backlight will be converted into linearly polarized light by the linear polarizing film 214 after passing through the linear polarizing film 214 , which has a single linear polarization direction. Then the linearly polarized light passes through the quarter-wavelength retardation film 218 . Based on the optical properties of the quarter-wavelength retardation film, the quarter-wavelength retardation film 218 converts linearly polarized light into circularly polarized light or elliptically polarized light.

The polarization direction of circularly polarized light or elliptically polarized light will rotate with time to form a circular or elliptical shape. Therefore, when passing through the multi-domain vertically aligned liquid crystal layer 206, the above-mentioned problem of dark cross lines can be avoided by using multiple polarization directions. . After passing through the MVA liquid crystal layer 206 , the circularly polarized light or elliptically polarized light passes through another quarter-wavelength retardation film 228 . As previously mentioned, the quarter-wavelength retardation film 228 must be perpendicular to the slow axis of the quarter-wavelength retardation film 218, so that the above-mentioned converted circularly polarized light or elliptically polarized light can be converted again The linearly polarized light is used for screening by the linear polarizing film 224 afterwards.

Regarding the above-mentioned absorption axes of the linearly stretched films 214 and 224 and the slow axes of the quarter-wave retardation films 218 and 228, the present invention also proposes a preferred relationship between them in another preferred embodiment, so as to Optimizing the compensation effect of the present invention. When the angle between the absorption axes of the linearly stretched films 214 and 224 and the slow axes of the quarter-wavelength retardation films 218 and 228 is 45 degrees, the quarter-wavelength retardation films 214 and 224 can linearly polarize The light is converted into a perfectly circularly polarized light, not an elliptically polarized light. That is to say, at this time, the polarization direction of light will be uniformly distributed in all directions as time changes, so under this condition, the compensation effect of the polarizing plate of the present invention is the best.

3A and FIG. 3B are schematic diagrams of another preferred embodiment of the present invention, illustrating the above-mentioned absorption axes of the linearly stretched films 214 and 224 and the sandwich between the slow axes of the quarter-wavelength retardation films 218 and 228. Two situations when the angle is 45 degrees. Firstly, it should be noted that the absorption axis 314 of the linear polarizing film 214 in these two figures is in the horizontal direction, while the absorption axis 324 of the linear polarizing film 224 is in the vertical direction.

In FIG. 3A, the slow axis 318a of the quarter-wavelength retardation film 218a and the slow axis 328a of the quarter-wavelength retardation film 228a are perpendicular to each other, and are respectively connected to the absorption axes 314 and 324 of the linear polarizing films 214 and 224. Hold a 45-degree angle. Similarly, in FIG. 3B, the slow axis 318b of the quarter-wavelength retardation film 218b and the slow axis 328b of the quarter-wavelength retardation film 228b are also perpendicular to each other, and are also respectively parallel to the linear polarizing films 214 and 224. The absorption axes 314 and 324 form an angle of 45 degrees.

In addition, when the slow axes of the two biaxially stretched films in the present invention are perpendicular to each other and the absorption axes of their adjacent linear polarizing films are respectively perpendicular to each other, the best viewing angle compensation effect can be obtained. FIG. 4 is a schematic diagram of another preferred embodiment of the present invention, illustrating the preferred relationship between the slow axis of the biaxially stretched film and the absorption axis of the linear polarizing film.

In FIG. 4 , the slow axis 316 of the biaxially stretched film 216 and the absorption axis 314 of the adjacent linear polarizing film 214 are perpendicular to each other. The slow axis 326 of another biaxially stretched film 226 is also perpendicular to the absorption axis 324 of the adjacent linear polarizing film 224 . Of course, the slow axes 316 and 326 of the biaxial absorbing films 216 and 226 are also perpendicular to each other, so that the best viewing angle compensation effect can be obtained.

Since the wavelength range of visible light from blue light to red light is approximately between 400nm and 700nm, the center wavelength of the above-mentioned quarter-wavelength retardation films 218 and 228 is usually selected around 480-600nm to achieve the best use. Effect. In this embodiment, the central wavelengths of the quarter-wavelength retardation films 218 and 228 are selected between 540-560 nm of green light. But in practice, the quarter-wavelength retardation film will have different selectivity for different wavelengths, that is to say, its effect of converting circularly polarized light is best at its center wavelength, while the conversion effect of other wavelengths depends on its Depends on the bandwidth range. Therefore, common narrow-band quarter-wavelength retardation films cannot obtain good conversion effects in such a large range of visible light (between 400nm and 700nm).

Therefore, the present invention also provides a broad band quarter-wavelength retardation film, so that the polarizing plate of the present invention can obtain a good conversion effect in the entire visible light wavelength range of 400nm to 700nm. Or, as another embodiment of the present invention, a combination of a half-wavelength retardation film and a quarter-wavelength retardation film is used to obtain a polarization equivalent to a broadband quarter-wavelength retardation film. Xiangguo.

Fig. 5A is another preferred embodiment of the present invention, in order to illustrate the above-mentioned combination of utilizing the half-wave retardation film and the quarter-wave retardation film to obtain the equivalent broadband quarter-wave Polarization effect of retardation film.

FIG. 5A adds two half-wavelength retardation films to the embodiment of FIG. 2A , wherein the half-wavelength retardation film 517 is located between the quarter-wavelength retardation film 218 and the biaxially stretched film 216. , and another half-wavelength retardation film 527 is located between the quarter-wavelength retardation film 228 and the biaxially stretched film 226 .

Similarly, FIG. 5B shows that two half-wavelength retardation films are added in the embodiment of FIG. 2B, wherein the half-wavelength retardation film 517 is located between the quarter-wavelength retardation film 218 and the biaxial Between the stretched films 216 , another half-wavelength retardation film 527 is located between the quarter-wavelength retardation film 228 and the biaxially stretched film 226 .

It should be noted that, in the above two embodiments, the broadband quarter-wavelength retardation films formed by the half-wavelength retardation films 517 and 527 and the quarter-wavelength retardation films 218 and 228 are equivalent to The slow axis of the linear polarizing films 214 and 224 can form an angle of 45 degrees with the absorption axes of the linear polarizing films 214 and 224 according to the preferred embodiment shown in FIG. 3A and FIG. 3B . In this way, this broadband quarter-wavelength retardation film can convert linearly polarized light in a large wavelength range into circularly polarized light, that is, the polarization direction of light can be uniformly distributed in all directions as time changes, so as to obtain the best performance. conversion effect.

According to a preferred embodiment of the present invention, when using this broadband quarter-wavelength retardation film, the slow axis of its half-wavelength retardation film 517 or 527 and the adjacent linear polarizing film 214 or 224 The angle between the absorption axes is in the range of 0 to 40 degrees. The angle between the slow axis of the quarter-wave retardation film 218 or 228 and the absorption axis of the adjacent linear polarizing film 214 or 224 ranges from 50 to 85 degrees.

Commonly used materials for the quarter or half wavelength retardation films 218 , 228 , 517 , 527 , the linear polarizing films 214 and 224 , and the protective films 212 and 222 in the present invention are discussed below. The retardation film used in the above embodiments is a uniaxially stretched retardation film, and its material is polynorbornene or polycarbonate (PC). Since polyvinyl alcohol (PVA) has a polarizing effect due to its stretching properties, it is generally used as the substrate of the linear polarizing films 214 and 224 in the present invention.

In addition, after stretching, the mechanical properties of the polyvinyl alcohol will be reduced and it will be easily broken. Therefore, protective films 212 and 222 are usually coated to prevent it from breaking. The material of the protective films 212 and 222 can be triacetyl cellulose (TAC), polycarbonate (polycarbonate) or polynorbornene (polynorbornene). On the one hand, it can protect the polyvinyl alcohol, and on the other hand, it can The linear polarizing films 214 and 224 made of polyvinyl alcohol are prevented from retracting.

The present invention uses a quarter-wavelength retardation film to convert the linearly polarized light originally entering the multi-domain vertically aligned liquid crystal layer into circularly polarized light, so as to avoid the conventional linearly polarized light in a single direction being directed parallel to the upper or lower Due to the influence of the liquid crystal molecules tilted in the direction of the absorption axis of the linear polarizing film, there is a problem of dark cross lines in the middle of the liquid crystal pixel. Therefore, the present invention can effectively improve the utilization rate of light, increase the brightness of the liquid crystal display in the bright state, and prolong the service life of the backlight lamp tube.

Although the present invention has been disclosed above with a preferred embodiment, it is not intended to limit the present invention. Any person familiar with the art may make various changes and substitutions without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims (13)

1. the Polarizer of a multi-domain vertical alignment liquid crystal displays comprises at least:

One first protective film;

One first linear polarizing film;

One first double shaft extensioning film;

One first quarter-wave phasic difference film;

One second quarter-wave phasic difference film;

One second double shaft extensioning film;

One second linear polarizing film; And

One second protective film;

This first protective film wherein; this first linear polarizing film; this first double shaft extensioning film; this first quarter-wave phasic difference film; this second quarter-wave phasic difference film; this second double shaft extensioning film; this second linear polarizing film and this second protective film are arranged in regular turn from a source backlight; and an absorption axes of this first linear polarizing film is vertical mutually with an absorption axes of this second linear polarizing film, and a slow axis of this first quarter-wave phasic difference film is vertical mutually with a slow axis of this second quarter-wave phasic difference film.

2. the Polarizer of a multi-domain vertical alignment liquid crystal displays comprises at least:

One first protective film;

One first linear polarizing film;

One first quarter-wave phasic difference film;

One first double shaft extensioning film;

One second double shaft extensioning film;

One second quarter-wave phasic difference film;

One second linear polarizing film; And

One second protective film,

This first protective film wherein; this first linear polarizing film; this first quarter-wave phasic difference film; this first double shaft extensioning film; this second double shaft extensioning film; this second quarter-wave phasic difference film; this second linear polarizing film and this second protective film are arranged in regular turn from a source backlight; and an absorption axes of this first linear polarizing film is vertical mutually with an absorption axes of this second linear polarizing film, and a slow axis of this first quarter-wave phasic difference film is vertical mutually with a slow axis of this second quarter-wave phasic difference film.

3. Polarizer as claimed in claim 1 or 2, the angle that it is characterized in that this slow axis of this absorption axes of this first linear polarizing film and this first quarter-wave phasic difference film are 45 degree.

4. Polarizer as claimed in claim 1 or 2 is characterized in that the scope of the centre wavelength of this first quarter-wave phasic difference film and this second quarter-wave phasic difference film is between between the 480nm to 600nm.

5. Polarizer as claimed in claim 1 or 2 is characterized in that this first quarter-wave phasic difference film and this second quarter-wave phasic difference film are two wideband quarter-wave phasic difference films.

6. Polarizer as claimed in claim 5 is characterized in that the effective wavelength range of those wideband quarter-wave phasic difference films comprises 400～700nm.

7. Polarizer as claimed in claim 1, it is characterized in that this first quarter-wave phasic difference film comprises one first narrow frequency quarter-wave phasic difference layer and one first narrow frequency 1/2nd wavelength phasic difference layers, and this second quarter-wave phasic difference film comprises one second narrow frequency quarter-wave phasic difference layer and one second narrow frequency 1/2nd wavelength phasic difference layers, these first narrow frequency 1/2nd wavelength phasic difference layers are between this first double shaft extensioning film and this first narrow frequency quarter-wave phasic difference layer, and these second narrow frequency 1/2nd wavelength phasic difference layers are between this second double shaft extensioning film and this second narrow frequency quarter-wave phasic difference layer.

8. Polarizer as claimed in claim 2, it is characterized in that this first quarter-wave phasic difference film comprises one first narrow frequency quarter-wave phasic difference layer and one first narrow frequency 1/2nd wavelength phasic difference layers, and this second quarter-wave phasic difference film comprises one second narrow frequency quarter-wave phasic difference layer and one second narrow frequency 1/2nd wavelength phasic difference layers, these first narrow frequency 1/2nd wavelength phasic difference layers are between this first linear polarizing film and this first narrow frequency quarter-wave phasic difference layer, and these second narrow frequency 1/2nd wavelength phasic difference layers are between this second linear polarizing film and this second narrow frequency quarter-wave phasic difference layer.

9. as claim 7 or 8 described Polarizers, the angle that it is characterized in that this slow axis of this absorption axes of this first linear polarizing film and this first narrow frequency quarter-wave phasic difference film is between 50 to 85 degree, and the angle of a slow axis of this absorption axes of this first linear polarizing film and these first narrow frequency 1/2nd wavelength phasic difference layers be between 0 to 40 spend between.

10. Polarizer as claimed in claim 1 or 2, a slow axis that it is characterized in that this first double shaft extensioning film is vertical mutually with a slow axis of this second double shaft extensioning film, and the angle of this slow axis of this absorption axes of this first linear polarizing film and this first double shaft extensioning film is 90 degree.

11. Polarizer as claimed in claim 1 or 2; the material that it is characterized in that this first protective film and this second protective film be triacetate fiber (triacetyl cellulose, TAC), polycarbonate (polycarbonate) or polynorbornene (polynorborene).

12. Polarizer as claimed in claim 1 or 2, the material that it is characterized in that this first linear polarizing film and this second linear polarizing film be polyvinyl alcohol (PVA) (polyvinyl alcohol, PVA).

13. Polarizer as claimed in claim 1 or 2, the material that it is characterized in that this first quarter-wave phasic difference film and this second quarter-wave phasic difference film is tributyl carbonate (polynorbornene) or polycarbonate (polycarbonate).

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