KR100290773B1 - Reflective wide viewing angle lcd - Google Patents

Abstract

PURPOSE: A reflective wide viewing angle LCD(Liquid Crystal Display) is provided to realize a wide viewing angle by installing a quarter wave plate and a reflective plate. CONSTITUTION: A reflective LCD comprises a first substrate(11), a second substrate(12) symmetric to the first substrate and spacing apart from the first substrate, a liquid crystal layer(15) formed between the interfaces of the first and second substrates, a polarization plate(18) formed on the non-facing surface, a quarter wave plate(17) formed between the non-facing surface and the polarization plate, orientation films(19,20) formed on respective interfaces of the first and second substrates, and a reflective plate(16) formed on one of the interfaces or the non-facing surface. A pixel electrode(13) and a counter electrode(14) for driving liquid crystal are formed in one or different parts. When forming electric fields(E1,E2) in the pixel electrode and the counter electrode, at least two domains are formed in the liquid crystal layer. Therefore, complete darkness and whiteness are realized without an optical correction film.

Description

Reflective wide viewing angle liquid crystal display

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the technology of a liquid crystal display device, and more particularly, to a reflection type liquid crystal display device comprising a quarter wave plate and a reflection plate to realize a wide viewing angle.

Reflective twisted nematic mode liquid crystal displays have a narrow viewing angle. In addition, the reflective hybrid aligned nematic mode liquid crystal display can implement full color, has a low driving voltage and a fast response speed. However, since the reflective hybrid aligned nematic mode liquid crystal display uses only the birefringence effect of the liquid crystal, gray scale inversion easily occurs depending on the viewing direction. This lowers the contrast.

In order to solve the gray level inversion, an optical compensation film is provided between the substrate and the polarizing plate of the liquid crystal display. However, the optical compensation film depends on the form of the liquid crystal of the liquid crystal layer used. That is, the refractive anisotropy of the liquid crystal used should be isotropic with the optical compensation film. Specifically, if the liquid crystal is rod-shaped, the liquid crystal constituting the optical compensation film should be disk-type, and if the liquid crystal is disk-shaped, the liquid crystal of the optical compensation film should be rod-shaped. Therefore, the production of the optical compensation film is difficult when applied to the liquid crystal display device.

Accordingly, an object of the present invention is to provide a liquid crystal display device having a wide viewing angle while solving the problem of gray level inversion without an optical compensation film.

1A is a cross-sectional view illustrating an off state of a liquid crystal display according to a first embodiment of the present invention.

1B is a cross-sectional view illustrating an on state of a liquid crystal display according to a first exemplary embodiment of the present invention.

Figure 2a is a perspective view showing the principle of operation of Figure 1a.

FIG. 2B is a perspective view showing the operating principle of FIG. 1B; FIG.

3A, 3B, 3C, and 3D are diagrams showing polarization states illustrating FIG. 2A.

4A, 4B, 4C, and 4D are diagrams showing polarization states illustrating FIG. 2B.

5A and 5B illustrate a liquid crystal display device according to a second embodiment of the present invention.

5A illustrates the structure of the counter electrode of the liquid crystal display device;

5B is a cross-sectional view of the liquid crystal display device employing the counter electrode of FIG. 5A.

6A and 6B illustrate a liquid crystal display according to a third exemplary embodiment of the present invention.

6A illustrates a structure of a pixel electrode of a liquid crystal display device,

6B is a cross-sectional view of a liquid crystal display device employing the pixel electrode of FIG. 6A.

7A and 7B illustrate a liquid crystal display device according to a fourth embodiment of the present invention.

7A illustrates the structure of the counter electrode of the liquid crystal display device;

FIG. 7B is a sectional view of the liquid crystal display device employing the counter electrode of FIG. 7A. FIG.

8A and 8B illustrate a liquid crystal display according to a fifth exemplary embodiment of the present invention.

8A illustrates a structure of a pixel electrode of a liquid crystal display device,

8B is a cross-sectional view of the liquid crystal display device employing the pixel electrode of FIG. 8A.

9 is a cross-sectional view of a lower portion of a liquid crystal layer of a sixth embodiment of the present invention.

Fig. 10 is a sectional view of the lower portion of the liquid crystal layer in the seventh embodiment of the present invention.

Fig. 11 is a cross sectional view of a lower portion of a liquid crystal layer of an eighth embodiment of the invention;

(Explanation of symbols for the main parts of the drawing)

11, 21, 31, 51, 61, 81, 91, 101: lower substrate

12, 22, 32, 52, 62: upper substrate 14, 24, 34, 54, 64, 89: counter electrode

13, 23, 33, 53, 63, 88, 98, 108: pixel electrode

18, 28, 38, 58, 68: polarizing plates 17, 27, 37, 57, 67: half-wave plate

16, 26, 36, 56, 66, 86, 96, 106: Reflector

19, 20, 29, 30, 39, 40, 59, 60, 69, 70, 90, 99, 109: vertical alignment layer

87, 97, 107: light transmitting layer for planarization

In order to achieve the object of the present invention, a quarter-wave plate is disposed between the upper substrate and the polarizing plate coated with the vertical alignment layer, and a reflecting plate is disposed on the rear or front surface of the lower substrate coated with the vertical alignment layer on the upper surface. Therefore, when no voltage is applied, light passing through the polarizing plate is linearly polarized to the right (or left), and the linearly polarized light is circularly polarized to the left (or right) through the quarter wave plate, and the circularly polarized light is reflected by the reflector. Circularly polarized in the right (or left) direction. The light then linearly polarizes to the left (or right) as it passes through the quarter-wave plate again. Therefore, since the axis of the light passing through the polarizing plate is perpendicular to the axis of the light passing through the quarter wave plate and incident on the polarizing plate, it is in a dark state. On the other hand, when the voltage is applied, the light passing through the polarizer is linearly polarized to the right (or left), and the linearly polarized light is circularly polarized to the left (or right) through the quarter wave plate, and the circularly polarized light is twisted nema Linearly polarized to the left (or right) while passing through the tick liquid crystal layer, and linearly polarized to the right (or left) by the reflecting plate. Next, the light is circularly polarized in the left (or right) direction while passing through the liquid crystal layer and linearly polarized in the right (or left) while passing through the half wave plate again. Therefore, since the axis of light incident through the polarizing plate and the axis of light passing through the quarter wave plate and incident on the polarizing plate are parallel, the light passes through the polarizing plate and becomes white.

According to a first embodiment of the present invention, a reflective liquid crystal display device includes a first substrate, a second substrate facing the first substrate, and spaced a predetermined distance apart, between the first substrate facing surface and the second substrate facing surface. And a polarizing plate formed on the non-facing surface of the first substrate, a quarter wave plate formed between the non-facing surface and the polarizing plate of the first substrate, and a reflecting plate formed on the non-facing surface of the second substrate.

The liquid crystal display of the second embodiment according to the aspect of the present invention further includes a pixel electrode, a counter electrode, and first and second vertical alignment layers in the liquid crystal display of the first embodiment. A pixel electrode is formed between the opposing surface of the second substrate and the liquid crystal layer, and the counter electrode is spaced apart from the pixel electrode in a predetermined plane on the same plane as the pixel electrode. A first vertical alignment layer is formed between the non-facing surface of the first substrate and the liquid crystal layer, and a second vertical alignment layer is formed between the pixel electrode, the counter electrode, and the liquid crystal layer to cover the second substrate on which the pixel electrode and the counter electrode are formed.

The liquid crystal display device of the third embodiment according to the aspect of the present invention further includes a pixel electrode, a counter electrode, and first and second vertical alignment layers in the liquid crystal display device of the first embodiment. The counter electrode is formed between the opposite surface of the first substrate and the liquid crystal layer and the pixel electrode is formed between the opposite surface of the second substrate and the liquid crystal layer. The first substrate alignment layer is formed between the counter electrode and the liquid crystal layer to cover the entire surface of the first substrate facing surface where the counter electrode is formed, and the second substrate alignment surface is formed between the pixel electrode and the liquid crystal layer so that the pixel electrode is formed. Cover the front. Here, one of the pixel electrode and the counter electrode includes at least one slit.

The liquid crystal display device of the fourth embodiment according to the aspect of the present invention further includes a pixel electrode, a counter electrode, and first and second vertical alignment layers in the liquid crystal display device of the first embodiment. The liquid crystal display device includes a first substrate, a second substrate facing the first substrate, and spaced a predetermined distance apart, a liquid crystal layer formed between the first substrate facing surface and the second substrate facing surface, a polarizer formed on the non-facing surface of the first substrate, A quarter wave plate formed between the non-facing surface of the first substrate and the polarizing plate, and a reflecting plate formed on the opposite surface of the second substrate.

The liquid crystal display device of the fifth embodiment according to the aspect of the present invention is the same as the light transmitting layer formed on the reflecting plate, the pixel electrode formed between the light transmitting layer and the liquid crystal layer, and the pixel electrode in the liquid crystal display device of the fourth embodiment. A counter electrode spaced apart from the pixel electrode in a plane by a predetermined distance, a first vertical alignment layer formed between the opposing surface of the first substrate and the liquid crystal layer, and light transmission formed between the pixel electrode and the counter electrode and the liquid crystal layer to form the pixel electrode and the counter electrode It further includes a second vertical alignment layer covering the entire layer.

According to an aspect of the present invention, a liquid crystal display device according to a sixth embodiment includes a counter electrode formed between an opposing surface of a first substrate and a liquid crystal layer on the liquid crystal display device of the fourth embodiment, a light transmitting layer formed on an upper surface of a reflecting plate, A pixel electrode formed on an upper surface of the planarizing light transmitting layer, a first vertical alignment layer formed between the counter electrode and the liquid crystal layer and covering the entire surface of the counter surface of the first substrate on which the counter electrode is formed, and formed between the pixel electrode and the liquid crystal layer. A second vertical alignment layer covering the entire surface of the formed light transmitting layer is further provided.

In a seventh embodiment liquid crystal display according to an aspect of the present invention, one of the pixel electrode and the counter electrode includes at least one slit.

On the other hand, in either embodiment, the liquid crystal of the liquid crystal layer may exhibit positive or negative dielectric anisotropy. In the case of positive dielectric anisotropy, only the long axis of the liquid crystal molecules is arranged along the electric field, and in the case of negative dielectric anisotropy, the short axis of the liquid crystal molecules is arranged along the electric field.

When no voltage is applied, a dark state is formed by the quarter-wave plate and the reflector, and when the voltage is applied, the white state is realized by the quarter-wave plate, the reflector, and the liquid crystal layer. In addition, two or more domains are formed in the liquid crystal layer when a voltage is applied. Thus, full dark and white states are achieved without the use of optical compensation films, increasing the contrast ratio and improving the viewing angle. Moreover, the rubbing speed of a liquid crystal display device increases by the rubbing process of a vertical alignment film.

EXAMPLE

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First embodiment

1A and 1B, the reflective liquid crystal display includes a lower substrate 11, an upper substrate 12 facing the lower substrate, a pixel electrode 13 formed in a stripe shape on an upper surface of the lower substrate 11, and the pixel electrode. In the same plane as (13), the counter electrode 14 spaced apart from the pixel electrode 13 by a predetermined distance, the first vertical alignment layer 19 coated on the upper substrate, the pixel electrode 13 and the counter electrode 14 A second vertical alignment layer 20 covering the upper surface of the formed lower substrate and a liquid crystal layer 15 formed between the first and second vertical alignment layers. In addition, the reflective liquid crystal display device includes a reflector 16 disposed on the rear surface of the lower substrate 11, a polarizer 18 disposed on the rear surface of the upper substrate, and a quarter wave plate disposed between the upper substrate 12 and the polarizer 18. (17) is further provided. A liquid crystal having positive dielectric anisotropy was used for the liquid crystal layer 15. The polarization axis of the polarizing plate forms 45 degrees with the direction of the electric field. The axis of the quarter-wave plate 17 forms 45 degrees with the transmission axis of the polarizing plate 18.

When no voltage is applied, as shown in FIGS. 1A and 2A, the long axes of all liquid crystals of the liquid crystal layer are vertically aligned with the upper substrate 12 and lower substrate 11 surfaces by the influence of the vertical alignment layers 19 and 20. . Only components in a predetermined direction among the unpolarized light sources pass through the polarizing plate 18. By the way, since the axis of the polarizing plate 18 forms 45 degrees with the direction of an electric field, light transmission becomes largest. Meanwhile, as shown in FIG. 3A, the horizontal component of the light passing through the polarizing plate 18 and the vertical component have the same size, the advancing direction of the polarized light is determined by the Z axis, and the light passing through the polarizing plate is determined as the right linearly polarized light. Assume that the phase of the component is faster than the phase of the y component. Since the quarter-wave plate 17 generates a phase difference of 90 degrees, i.e., 90 degrees, in the normal path and the abnormal path, when the right linearly polarized light passes through the quarter-wave plate 17, as shown in FIG. 3B. Left circularly polarized. Since all the liquid crystals 15a of the liquid crystal layer 15 are arranged in the Z direction, the light passing through the quarter-wave plate 17 passes through the liquid crystal layer 15 without phase change. Since the traveling direction of the light reflected by the reflector 16 changes to -Z, the x component (or y component) of light passing through the liquid crystal layer 15 and incident on the reflector 16 is x of the light reflected by the reflector 16. Since it has a phase difference of 180 degrees with the component (or y component), as shown in FIG. 3C, the left circularly polarized light before reflection is right circularly polarized. The right circularly polarized light passes through the liquid crystal layer 15 as it is and enters into the quarter-wave plate 17 again. While passing through the quarter wave plate 17, the phase of the light before and after passing through the quarter wave plate 17 is 90 degrees so that left linearly polarized light as shown in FIG. 3D. However, since the linearly polarized light shown in FIG. 3A coincides with the polarization axis of the polarizing plate and the optical axis shown in FIG. 3A and the optical axis shown in FIG. 3D cross each other vertically, the light incident from the quarter wave plate 17 into the polarizing plate 18 passes through the polarizing plate 18. can not do. Thus forming a dark state.

On the other hand, when voltage is applied, as shown in FIGS. 1B and 2B, liquid crystals directly contacting the substrate surface under the influence of the vertical alignment layers 19 and 20 maintain a state in which no voltage is applied. In the central portion of the pixel electrode 13 and the counter electrode 14, the long axis of the liquid crystals is canceled out such that the horizontal component of the electric field by the pixel electrode 13 and the counter electrode 14 cancels out and only the vertical component remains to be in contact with the substrate. It is arranged perpendicular to the surface of the upper substrate 12 and the lower substrate 11. Since the horizontal electric field E1 and the elliptical fringe electric field E2 are formed between the pixel electrode 13 and the counter electrode 14, liquid crystal molecules are arranged along the electric field E1 and the electric field E2. Therefore, two domains which are symmetrical with respect to the center line of the pixel electrode and the counter electrode are formed except for the portion in contact with the substrate.

Looking at the progress of the light, only the components in a predetermined direction of the non-polarized light source passes through the polarizing plate 18, the incident light is linearly polarized as shown in Figure 3a. When passing through the quarter wave plate 17, linearly polarized light becomes left circularly polarized as shown in FIG. 3B. All of the liquid crystals 15a of the liquid crystal layer 15 form a double domain that is symmetrically around the pixel electrode 13 and the counter electrode 14, and are adjacent to the liquid crystal adjacent to the first vertical alignment layer and the second alignment layer. Since the twist angle of the liquid crystal forms 90 degrees, the light passing through the liquid crystal layer 15 again undergoes a phase change of 90 degrees and is left linearly polarized as shown in FIG. 4A. The light reflected by the reflector 16 is changed to the left linearly polarized light before the reflection, as shown in Fig. 4B. The right linearly polarized light passes through the liquid crystal layer 15 again, causing a phase change of 90 degrees and left circularly polarized light as shown in FIG. 4C. After that, it enters into the quarter wave plate 17. While passing through the quarter wave plate 17, the phase of the light before and after passing through the quarter wave plate 17 is 90 degrees so that the linearly polarized right is shown, as shown in FIG. 4D. However, since the linearly polarized light shown in FIG. 3A coincides with the polarization axis of the polarizing plate and the optical axis shown in FIG. 3A and the optical axis shown in FIG. 4D are parallel, the light incident from the quarter wave plate 17 into the polarizing plate 18 passes through the polarizing plate 18. . That is, form a white state.

The manufacturing method of this embodiment is described.

The upper substrate 12 and the lower substrate 11 to face the upper substrate 12 are prepared. The first vertical alignment layer 19 is coated on the opposite surface of the upper substrate. The pixel electrode 13 and the counter electrode 14 are formed on the opposite surface of the lower substrate 11. The pixel electrode 13 and the counter electrode 14 are made of an opaque metal. Next, a second vertical alignment layer 20 is coated on the entire surface of the lower substrate on which the pixel electrode 13 and the counter electrode 14 are formed. Next, the upper substrate 12 and the lower substrate 11 are bonded to each other. Next, a quarter wave plate 17 is attached to the non-facing surface of the upper substrate. Next, the polarizing plate 18 is attached to the quarter wave plate 17. On the other hand, the reflecting plate 16 is attached to the non-facing surface of the lower substrate. Thereafter, a liquid crystal having a positive anisotropy dielectric constant is injected into the space formed by the upper substrate and the lower substrate and sealed.

Although a liquid crystal having a positive anisotropy dielectric constant is used, a liquid crystal having a negative anisotropy dielectric constant may be injected into the liquid crystal layer 15.

Furthermore, after forming the first vertical alignment layer 19 and the second vertical alignment layer 20, the alignment layer may be rubbed in the length direction of the pixel electrode, respectively. It is possible to form a double domain without performing separate rubbing treatment on the alignment film. However, when the rubbing treatment is performed on the vertical alignment layer in the longitudinal direction of the pixel electrode, the liquid crystal molecules of the liquid crystal layer are all aligned in one direction with one uniform tilt angle. Therefore, the response speed is increased compared with the case where no rubbing process is performed.

Second embodiment

5A and 5B, the upper substrate 22, the lower substrate 21, the pixel electrode 23, the counter electrode 24, the first vertical alignment layer 29, the second vertical alignment layer 30, and the liquid crystal layer ( 25, the reflecting plate 26, the polarizing plate 28, and the half-wave plate 27 are formed of the upper substrate 12, the lower substrate 11, the pixel electrode 13, the counter electrode 14 of FIGS. 1A and 1B. It corresponds to the 1st vertical alignment film 19, the 2nd vertical alignment film 20, the liquid crystal layer 15, the reflecting plate 16, the polarizing plate 18, and the quarter wave plate 17. As shown in FIG. 1A and 1B, the counter electrode 14 is formed on the lower substrate 12, but in this embodiment, the counter electrode 24 is formed on the upper substrate 22. In addition, as shown in FIG. 5A, the counter electrode 24 has at least one rectangular slit S1 formed therein. The width W1 of the slit is designed to be smaller than the width W2 between the slit and the slit. The counter electrode 24 having the pixel electrode 23 and the slit S1 is disposed on the lower substrate 21 and the upper substrate 22, respectively, so that an electric field is formed between them, and at the same time, the slit of the counter electrode is centered. Since a symmetrical electric field is formed, the sum of these two types of electric fields finally appears as E3. In FIG. 4B, a counter electrode including three slits is shown, forming a double domain around each slit. In addition, the electric field E3 is symmetric about the center of the counter electrodes 24b and 24c between the slit and the slit.

The operating principle when no voltage is applied and when voltage is applied is the same as in the first embodiment. That is, when no voltage is applied, light linearly polarized by the polarizing plate 28 passes through the quarter wave plate 27 and is circularly polarized and passes through the liquid crystal layer 25. Next, the traveling direction of the light is changed by 180 degrees by the reflecting plate 26 so that the light passing through the liquid crystal layer 25 is circularly polarized in the opposite direction to the circularly polarized light passing through the quarter wave plate 27. Furthermore, linearly polarized light passes through the liquid crystal layer 25 without phase change and passes through the quarter-wave plate 27 again. However, the light passing through the polarizing plate 28 and the light entering the polarizing plate 28 through the quarter wave plate 27 are in a quantum linear polarization state or their optical axes are orthogonal, so the light entering the polarizing plate 28 is the polarizing plate 28. Do not pass. When voltage is applied, linearly polarized light, circularly polarized light, linearly polarized light, while passing through the polarizing plate 28, quarter wave plate 27, liquid crystal layer 25, reflecting plate 26, liquid crystal layer 25, and quarter wave plate 27, Linearly polarized light, circularly polarized light and linearly polarized light. However, unlike when no voltage is applied, since the light passing through the polarizing plate 28 and the light incident on the polarizing plate 28 through the quarter wave plate 27 are parallel, the light reflected by the reflecting plate 26 is polarized ( Pass 28).

Similar to the manufacturing method of the liquid crystal display of the first embodiment, except that the counter electrode 24 is formed on the opposite surface of the upper substrate 22, and then the first vertical alignment layer 29 is formed and the lower substrate 21 is formed. The point where only the pixel electrode 23 is formed on the upper surface is different. Further, a mask pattern different from that of the first embodiment is used to form the counter electrode with the slit.

Third embodiment

6A and 6B, the upper substrate 32, the lower substrate 31, the pixel electrode 33, the counter electrode 34, the first vertical alignment layer 39, the second vertical alignment layer 40, and the liquid crystal layer ( 35, the reflecting plate 36, the polarizing plate 38, and the half-wave plate 37 are formed of the upper substrate 12, the lower substrate 11, the pixel electrode 13, the counter electrode 14 of FIGS. 1A and 1B. It corresponds to the 1st vertical alignment film 19, the 2nd vertical alignment film 20, the liquid crystal layer 15, the reflecting plate 16, the polarizing plate 18, and the quarter wave plate 17. As shown in FIG. In the second embodiment, the slit is formed on the counter electrode. However, in the present embodiment, the pixel electrode 33 formed on the upper surface of the lower substrate 31 includes the slit S2. The slit width W3 is designed to be smaller than the width W4 between the slit and the slit. However, since the thin film transistor T1, which is a switching device for driving the pixel electrode 33, is formed on the lower substrate 31, the pixel electrode 33 is formed in a region defined by the data line 44 and the gate line 41a. The thin film transistor T1 is formed in a region except for the portion where the thin film transistor T1 is disposed. Reference numeral 44a is a source of the thin film transistor and 44b is a drain of the thin film transistor.

When voltage is applied to the pixel electrode 33 and the counter electrode 34, the electric field E4 is formed. The electric field E4 corresponds to the electric field E3 of the second embodiment and is symmetric about the center lines of the slit S2 and the pixel electrode 33b.

Therefore, it can be seen that the operation of this embodiment when no voltage is applied and when voltage is applied is the same as that of the second embodiment. Therefore, description of the operation of the present embodiment is omitted.

In the manufacturing method, it is similar to the manufacturing method of the liquid crystal display device of the first embodiment, except that the counter electrode 34 is formed on the opposite surface of the upper substrate 32 and then the first vertical alignment layer 39 is formed. The difference is that only the pixel electrode 33 is formed on the upper surface of the lower substrate 31. In addition, a mask pattern different from the first and second embodiments is used to form the pixel electrode with the slit.

Fourth embodiment

7A and 7B, the upper substrate 52, the lower substrate 51, the pixel electrode 53, the counter electrode 54, the first vertical alignment layer 59, the second vertical alignment layer 60, and the liquid crystal layer ( 55, the reflecting plate 56, the polarizing plate 58, and the half-wave plate 57 are formed of the upper substrate 12, the lower substrate 11, the pixel electrode 13, the counter electrode 14 of FIGS. 1A and 1B. It corresponds to the 1st vertical alignment film 19, the 2nd vertical alignment film 20, the liquid crystal layer 15, the reflecting plate 16, the polarizing plate 18, and the quarter wave plate 17. As shown in FIG. As in the second embodiment, the counter electrode 54 has a slit S3. However, the slits S1 of the second embodiment are three (or two or more), each of which is a rectangle and is spaced a predetermined distance from the adjacent slit. Is set. Circularly projecting electrodes 54c and rod-shaped electrodes 54b are disposed in the center of the recessed rectangular frame. However, as shown in Fig. 7B, the cross section is similar to the second embodiment, and an electric field E5 similar to the electric field E3 is formed. Thus, it can be seen that the operation of this embodiment is the same as that of the first embodiment. Therefore, the description of the operation is omitted in the present embodiment.

The manufacturing method of this embodiment is also similar to the manufacturing method of the liquid crystal display of the second embodiment, except that the mask pattern for forming the counter electrode 54 is different from the mask pattern for the counter electrode 24 used in the second embodiment. use.

Fifth Embodiment

8A and 8B, the upper substrate 62, the lower substrate 61, the pixel electrode 63, the counter electrode 64, the first vertical alignment layer 69, the second vertical alignment layer 70, and the liquid crystal layer ( 65, the reflecting plate 66, the polarizing plate 68, and the half wave plate 67 are formed of the upper substrate 12, the lower substrate 11, the pixel electrode 13, the counter electrode 14 of FIGS. 1A and 1B. It corresponds to the 1st vertical alignment film 19, the 2nd vertical alignment film 20, the liquid crystal layer 15, the reflecting plate 16, the polarizing plate 18, and the quarter wave plate 17. As shown in FIG.

In the fourth exemplary embodiment, slits are formed on the counter electrode. However, in the present exemplary embodiment, the pixel electrode 63 formed on the upper surface of the lower substrate 61 includes the slits S4. However, since the thin film transistor T2, which is a switching device for driving the pixel electrode 63, is formed on the lower substrate 61, the pixel electrode 63 is formed in a region defined by the data line 73 and the gate line 71a. The thin film transistor T2 is formed in a region except for the portion where the thin film transistor T2 is disposed. Reference numeral 73a is a source of the thin film transistor and 73b is a drain of the thin film transistor.

When voltage is applied to the pixel electrode 63 and the counter electrode 64, an electric field E6 is formed. The electric field E6 corresponds to the electric field E5 of the fourth embodiment and is symmetric about the center lines of the slit S4 and the pixel electrode 63b.

Therefore, it can be seen that the operation of this embodiment when no voltage is applied and when voltage is applied is the same as that of the fourth embodiment. Therefore, description of the operation of the present embodiment is omitted.

The manufacturing method of this embodiment is also similar to the manufacturing method of the liquid crystal display of the third embodiment, except that the mask pattern for forming the pixel electrode 63 is different from the mask pattern for the pixel electrode 33 used in the third embodiment. use.

Sixth embodiment

9 is a cross-sectional view of the lower part of the liquid crystal layer of the liquid crystal display, and the upper structure of the liquid crystal layer is the same as that of the first embodiment. The reflective plate 86 is disposed on the upper surface of the lower substrate 81. The surface of the reflecting plate 86 has protrusions (not shown). Therefore, when the electrode and the alignment film are directly formed on the upper surface of the reflecting plate, since the arrangement of the liquid crystal is not vertically aligned, the surface of the reflecting plate 86 must be flattened. To this end, the planarizing light transmitting layer 87 made of a material having light transmitting properties is formed. Next, the pixel electrode 88 and the counter electrode 89 are formed on the upper surface of the planarizing light transmitting layer 87. Thereafter, a vertical alignment layer 90 is coated on the entire surface of the planarizing light transmitting layer 87 on which the pixel electrode 88 and the counter electrode 89 are formed.

When no voltage is applied or when voltage is applied, the lower substrate 81 does not affect the path of light incident through the liquid crystal layer and incident on the reflecting plate 86, and thus exhibits the same operating characteristics as in the first embodiment. Therefore, the description of the operation of this embodiment is omitted.

Seventh embodiment

FIG. 10 is a cross-sectional view of the lower portion of the liquid crystal layer of the liquid crystal display, and the upper structure of the liquid crystal layer is the same as that of the second and fourth embodiments. The reflective plate 96 is disposed on the upper surface of the lower substrate 91. As described in the sixth embodiment, since the surface of the reflecting plate 96 has protrusions, a planarizing light transmitting layer 97 made of a material having light transmitting properties is formed on the upper surface of the reflecting plate 96. Next, the pixel electrode 98 is formed on the upper surface of the planarizing light transmitting layer 97. Thereafter, a vertical alignment layer 89 is coated on the entire surface of the planarizing light transmitting layer 97 on which the pixel electrode 98 is formed.

The operating principle of the liquid crystal display device of this embodiment is the same as that of the second and fourth embodiments.

Eighth embodiment

FIG. 11 is a cross-sectional view of the lower part of the liquid crystal layer of the liquid crystal display, and the upper structure of the liquid crystal layer is the same as that of the third and fifth embodiments. The reflective plate 106 is disposed on the upper surface of the lower substrate 101. As described in the seventh embodiment, since the surface of the reflecting plate 106 has protrusions, the planarizing light transmitting layer 107 made of a material having light transmitting properties is formed on the upper surface of the reflecting plate 106. Next, the pixel electrode 108 having one or more slits is formed on the top surface of the planarizing light transmitting layer 107. Thereafter, a vertical alignment layer 109 is coated on the entire surface of the planarization light transmitting layer 107 on which the pixel electrode 108 is formed.

The operating principle of the liquid crystal display device of this embodiment is the same as that of the third embodiment and the fifth embodiment.

In the first to eighth embodiments, the liquid crystal molecules of the liquid crystal layer form left and right symmetrical double domains when voltage is applied, so that the left and right viewing angles are improved. In addition, since the dark state and the white state are implemented without using the HAN mode and the optical compensation film, the gray level reversal and the difficulty of manufacturing the optical compensation film of the liquid crystal display device generated when using them are not fundamentally generated.

Meanwhile, in the liquid crystal display of the present invention, the twist angle of the liquid crystal layer is 0 degrees or 90 degrees depending on whether it is a quarter wave plate disposed between the polarizing plate and the upper substrate, the reflecting plate disposed on the lower substrate, and whether voltage is applied. By adjusting the phase of the incident light by using the image, a dark state and a white state are realized. Therefore, since the dark state or the white state is not affected by the shape of the liquid crystal of the liquid crystal layer, the selection of the liquid crystal used in the liquid crystal layer is free.

Claims (12)

First substrate, A second substrate facing the first substrate and spaced a predetermined distance apart; A liquid crystal layer formed between the first substrate facing surface and the second substrate facing surface, A polarizing plate formed on a non-facing surface of the first substrate, A quarter-wave plate formed between the non-facing surface of the first substrate and the polarizing plate, and An alignment film formed on each of the opposing surface of the first substrate and the opposing surface of the second substrate, and And a reflecting plate formed on one of the non-facing surfaces and the opposing surfaces of the second substrate, The pixel electrode and the counter electrode for driving the liquid crystal layer are respectively formed in the same engine or different engines, And when forming an electric field in the pixel electrode and the counter electrode, a double domain is formed in the liquid crystal layer. The display panel of claim 1, wherein the reflective plate is formed on an opposite surface of the second substrate, the pixel electrode is formed on an opposite surface of the second substrate, and the counter electrode is formed on an opposite surface of the first substrate. The alignment film is a liquid crystal display device, characterized in that the vertical alignment film. The counter electrode of claim 1, wherein the reflecting plate is formed on a non-facing surface of the second substrate, and a counter electrode is formed between the opposite surface of the first substrate and the liquid crystal layer, and the opposite surface of the second substrate and the liquid crystal layer. A pixel electrode formed therebetween, a first vertical alignment layer formed between the counter electrode and the liquid crystal layer to cover the entire surface of the first substrate facing surface on which the counter electrode is formed, and formed between the pixel electrode and the liquid crystal layer; And a second vertical alignment layer covering an entire surface of the formed second substrate opposing surface. The liquid crystal display of claim 2, wherein the liquid crystal of the liquid crystal layer has positive dielectric anisotropy. The liquid crystal display of claim 3, wherein the liquid crystal of the liquid crystal layer has positive dielectric anisotropy. 4. The liquid crystal display device according to claim 3, wherein at least one slit is formed in one of the pixel electrode and the counter electrode. The liquid crystal display device according to claim 6, wherein the slit has a rectangular shape. The liquid crystal display of claim 7, wherein the width of the slit is smaller than the width between the slit and the slit. 7. The liquid crystal display device according to claim 6, wherein one of the pixel electrode and the counter electrode has a rectangular slit in which a center portion is recessed. 2. The planarizing light transmitting layer of claim 1, wherein the reflecting plate is formed on an opposing surface of the second substrate, the pixel electrode formed between the planarizing light transmitting layer and the liquid crystal layer, and the pixel. A counter electrode spaced apart from the pixel electrode by a predetermined distance in the same plane as the electrode, a first vertical alignment layer formed between the opposing surface of the first substrate and the liquid crystal layer, and formed between the pixel electrode, the counter electrode, and the liquid crystal layer And a second vertical alignment layer covering an entire surface of the planarizing light transmitting layer on which the pixel electrode and the counter electrode are formed. The semiconductor device of claim 1, wherein the reflective plate is formed on an opposite surface of the second substrate, the pixel electrode is formed on the reflective plate, and is formed on an opposite surface of the first substrate, and the alignment layer is a vertical alignment layer. The liquid crystal display device further comprises a light transmitting layer between the reflecting plate and the pixel electrode. The liquid crystal display of claim 11, wherein one of the pixel electrode and the counter electrode includes at least one slit.

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