KR100246926B1 - Reflection lcd device - Google Patents

Abstract

The present invention relates to a reflective liquid crystal display device which provides a vertical incident means to one surface of a substrate or a polarizing plate in contact with external light to focus most of the external light more vertically on a reflecting plate surface, wherein the vertical incident means continuously bends from one direction to another. A plurality of curved portions formed by forming a plurality of curved portions formed on one surface facing the substrate or the polarizing plate to focus a plurality of external light incident in at least two directions to the reflecting plate or a plurality of polygonal portions having a polygonal structure having at least three surfaces or more in succession. It consists of a condensing plate which is formed in one surface facing a board | substrate or a polarizing plate, and focuses the majority of the external light which enters in at least three directions to a reflecting plate. Accordingly, most of the external light incident at a predetermined angle is refracted in the direction more perpendicular to the reflection plate, thereby minimizing scattering or diffuse reflection factors on the surface of the reflection plate to improve the vertical reflectance of the reflection plate in the area where the user is located. Has the effect of further improving the luminance.

Description

Reflective LCD

The present invention relates to a reflective liquid crystal display device, and more particularly, by concentrating most of the external light incident at various angles in a direction more perpendicular to the reflection plate surface, an improved contrast and improved contrast can be realized by using light that is incident vertically. The present invention relates to a reflective liquid crystal display device.

In general, the reflection type liquid crystal display device is a method of reflecting external light passing through the substrate and the liquid crystal layer back to the user direction by installing a reflector having a high reflectance instead of a light source, and is capable of driving at a lower power than the light source type in which the light source is installed. It has a more advantageous advantage in compact and lightweight.

Such a reflective liquid crystal display device is generally provided as two transparent substrates, a liquid crystal cell having a pixel electrode, a scanning electrode, and an alignment liquid crystal on opposite surfaces of the substrate, and one surface of a substrate disposed at the bottom of the substrate. It is provided with a reflecting plate or the like.

The pixel electrode and the scan electrode are arranged such that a plurality of conductive films are orthogonal to each other so that the orthogonal portion forms a single pixel, and the respective voltage waveforms are applied to the pixel electrode and the scan electrode, respectively, The image is changed while the arrangement is changed, which corresponds to a conventional STN type liquid crystal display device. In the case of a TFT liquid crystal display device, a common electrode and a pixel electrode formed on opposite surfaces between substrates, and the pixel electrode It is provided with TFT which is a switching element which drives a liquid crystal to a bottom face.

In addition, a reflector is provided on one surface of the substrate disposed on a bottom surface of the substrate, and the reflector has a function of recognizing an image of the liquid crystal display device to a user by reflecting external light passing through the substrate and the liquid crystal layer toward the user direction. .

However, the conventional reflective liquid crystal display device has a problem in that the light utilization efficiency is deteriorated because a large probability that most of the external light incident at a predetermined angle is scattered or diffusely reflected on the reflecting plate surface.

Therefore, the present invention has been made to solve the above problems, an object of the present invention is to focus the majority of the external light incident at various angles in a direction more perpendicular to the reflecting plate to improve the light utilization efficiency of the reflecting plate further improved brightness The present invention provides a reflective liquid crystal display device.

In order to achieve the above object, the present invention provides a liquid crystal cell comprising two transparent substrates arranged in parallel at predetermined intervals, and a liquid crystal injected between the alignment layer and the alignment layer on electrodes formed on opposite surfaces of the substrate. And a reflecting plate installed on one surface of one of the substrates to reflect external incident light, and provided to a substrate to which external incident light is incident, thereby focusing the external incident light onto the reflecting plate to improve vertical incidence of external incident light. Provided is a reflective liquid crystal display device including vertical incidence means.

In addition, a liquid crystal cell comprising two transparent substrates arranged in parallel at predetermined intervals, an alignment layer and liquid crystal injected between the alignment layers on electrodes formed on opposite surfaces of the substrate, and one surface of one of the substrates. A reflecting plate provided to reflect external incident light, a polarizing plate provided on at least one of the substrates to selectively transmit only external incident light in a constant vibration direction, and provided to a substrate or polarizing plate side to which the external incident light is incident to the external incident light It provides a reflective liquid crystal display device comprising a vertical incidence means for focusing the light to the reflecting plate to improve the vertical incidence of external incident light.

The vertical incidence means may be provided as a focusing plate for arranging a plurality of bent parts continuously bent along one direction from one direction to one surface facing the substrate or the polarizing plate to focus a plurality of external light incident in at least two directions to a reflecting plate, or In addition, a plurality of polygonal portions having a polygonal structure having at least three surfaces or more formed in succession are formed on one surface facing the substrate or the reflecting plate to provide a focusing plate for focusing a plurality of external light incident in at least three directions to the reflecting plate.

Accordingly, a plurality of external light incident on the liquid crystal display device having various inclinations in various directions may be refracted in a direction more perpendicular to the reflection plate and then incident to improve reflection efficiency of the reflection plate, thereby realizing improved luminance.

1 is a cross-sectional view of a reflective liquid crystal display device according to a first embodiment of the present invention.

2 is a cross-sectional view of a reflective TFT liquid crystal display device according to a second embodiment of the present invention.

3 is a partially enlarged sectional view showing a first embodiment of a focusing plate.

4 is a partially enlarged cross-sectional view showing a second embodiment of a focusing plate.

5 is a partially enlarged cross-sectional view of FIG.

6 is a partially enlarged cross-sectional view showing another embodiment of the focusing plate.

7 is a schematic perspective view of the focusing plate showing the focusing function of the focusing plate.

8 is a partially enlarged sectional view showing a third embodiment of a focusing plate.

9 is a partially enlarged sectional view showing a fourth embodiment of a focusing plate.

10 is a partially enlarged cross-sectional view of FIG. 1 showing a reflecting plate.

11 is a cross-sectional view of a reflective liquid crystal display device according to a third embodiment of the present invention.

12 is a cross-sectional view of a reflective liquid crystal display device according to a fourth embodiment of the present invention.

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

1 is a cross-sectional view of a reflective liquid crystal display device according to a first embodiment of the present invention. The reflective liquid crystal display device newly implemented by the present invention includes two transparent upper and lower substrates 2 and 4 and the substrate 2. A liquid crystal cell 36 having a liquid crystal LC oriented by the pixel electrode 6, the scan electrode 8, and the alignment layer 10 on the opposite surface of the substrate 4, and one surface of the lower substrate 4. It includes a reflecting plate 12 is disposed in the vertical direction means disposed on one surface of the upper substrate (2).

2 is a cross-sectional view of a reflective TFT liquid crystal display device according to a second embodiment of the present invention, including two transparent substrates 2 and 4, a TFT 38 which is a switching element for driving a liquid crystal LC, A common filter 40 and a pixel electrode 42 formed on opposite surfaces of the substrates 2 and 4, a color filter 44 for implementing colors including three basic colors of dye, and the lower substrate ( And a vertical incidence means disposed on one surface of the upper substrate 2 on which the external incident light is incident.

The vertical incidence means refracts most of the external light incident to the liquid crystal display device at various angles in a direction more perpendicular to the reflecting plate 12 to focus the external light. The vertical incidence means extends from one direction to the other direction. It consists of a converging plate 16 arranged in a plurality of bent portion 14 that is continuously bent to form a surface facing the substrate (2).

In the first embodiment of the focusing plate 16, the bent portion 14 is sharply formed with a predetermined angle as shown in FIG. 3, and the second embodiment is the bent portion 18 as shown in FIG. Forms a gentle curve at predetermined intervals and is formed on one surface facing the upper substrate 2.

The focusing plate 16 having such a structure focuses a large number of external light incident in at least two directions to the upper substrate 2 and transmits the reflected light to the reflecting plate 12. As shown in FIG. 5, the external light incident on the focusing plate 16 at a predetermined angle is refracted in a direction more perpendicular to the upper substrate 2 while passing through the curved portion 14. do.

This is because the focusing plate 16 is made of a transparent polymer material, particularly preferably made of a transparent acrylic material, the refractive index of the focusing plate 16 generally has a larger value than that of air.

Accordingly, when an arbitrary line perpendicular to the inclined surface of the bent portion 14 formed on the focusing plate 16 is drawn (shown by a dashed line), the external light (shown by an arrow) incident at an angle of a1 with respect to the single dashed line is curved portion ( 14 is incident on the upper substrate 2 while passing the inclined surface at an angle of a2 larger than the angle of a1, so that the inclined surface is refracted in the direction more perpendicular to the upper substrate 2 and is incident.

That is, since there is a difference in the refractive index of the polymer material constituting the focusing plate 16 and the refractive index of the air layer through which the external light is incident while passing through the inclined surface of the curved portion 14, the phenomenon as shown in FIG. Most of the external light is focused in a direction more perpendicular to the upper substrate (2) can be delivered to the reflecting plate (12).

The bent portion 14 of the focusing plate 16 is formed to be in contact with a fine air layer as shown, but to form a more stable focusing plate 16, the outer surface of the bent portion 14, that is, between each bent portion 14 It is preferable to further include the formation of a second polymer film 22 having a refractive index lower than its refractive index in the space portion to be formed, which is shown in FIG. 6, wherein the focusing plate 16 faces external light. The first polymer film 20 to form the bent portion 14 toward the upper substrate 2, and the second polymer film 22 formed by the outer surface of the bent portion 14 of the first polymer film 20 Is done.

Accordingly, the focusing plate 16 may have a more stable structure, and may attach the focusing plate 16 to one surface of the upper substrate 2 without damaging the bent portion 14.

As described above, the focusing plate 16 forming the bent portion 14 focuses a plurality of external light incident in at least two directions to the upper substrate 2, which is illustrated in FIG. 7. Since a plurality of bent portions 14 are continuously formed in one direction and bent along the other direction, most of the external light (arrow shown) incident at a predetermined angle in the A and B directions is an inclined surface formed by the bent portion 14. As shown in FIG. 2, the focusing is performed by refraction in a direction more perpendicular to the upper substrate 2, but most of the external light incident at a predetermined angle in the C and D directions is difficult to expect a clear focusing effect.

Accordingly, the following embodiments of the focusing plate 16 are designed to focus a plurality of external light incident in at least three directions to the upper substrate 2, wherein the focusing plate 16 has a polygon having at least three surfaces. A plurality of polygonal portions having a continuous structure are formed on one surface facing the upper substrate 2.

The third embodiment of the focusing plate 16 is shown in FIG. 8, and the polygonal part 24 facing the upper substrate 2 is shown to face the upper part of the drawing. In the polygonal portion 24 of FIG. 2, a plurality of square pyramids 28 are formed in a predetermined pattern, and FIG. 9 is a fourth embodiment of the focusing plate 16. Is formed by combining a plurality of cones 30 to form a predetermined pattern.

The polygonal portion 24 of the focusing plate 16 shown in the third embodiment is a modification of the bent portion 14 shown in the first embodiment, and the bending direction is changed from one direction to the other direction, and It was bent once again from one direction to the other along the vertical direction.

Accordingly, the polygonal portion 24 of the focusing plate 16 having the plurality of square pyramids 28 refracts most of the external light incident in the direction in which the polygonal surface faces in the direction more perpendicular to the upper substrate 2. It focuses on the reflecting plate 12, which is to refract most of the incident light having a predetermined inclination in four directions facing each other while passing through the polygonal part to focus in a direction more perpendicular to the upper substrate 2. The principle of refraction thereof is the same as that shown in FIG.

The focusing plate 16 having the polygonal part 24 in which the plurality of quadrangular pyramids 28 is formed in a predetermined pattern and combined is focused on at least four directions of external light incident to at least four directions as illustrated in the upper substrate 2. In addition, the deformation of the polygonal portion 24 formed of the quadrangular pyramid 28 is a cone 30 pattern shown in FIG. 9, which focuses a large number of external light incident on the upper substrate 2 in at least four directions. .

The focusing plate 16 having the polygonal part 24 is also preferably made of a transparent polymer material having a high refractive index as in the above embodiment, and prevents damage to the polygonal parts 24 and 26 and stabilizes the focused focusing plate. It is preferable that the second polymer material is formed to have a refractive index lower than its own refractive index in the space portion formed between the polygonal portions 24 and 26 to form (16).

Accordingly, the external light focused through the focusing plate 16 reaches the reflecting plate 12 through the liquid crystal cell 36, and the reflecting plate 12 receives the external light (shown by the arrow) incident on the surface toward the user. As reflected, this reflects most of the external light incident in the vertical direction as shown in FIG. 10 in the vertical direction.

The following is a third embodiment of a reflective liquid crystal display device according to the present invention. FIG. 11 shows two transparent upper and lower substrates 2 and 4 and the pixel electrodes 6 facing opposite surfaces of the substrates 2 and 4. A liquid crystal cell 36 including a liquid crystal LC oriented by the scan electrode 8 and the alignment layer 10, a reflector 12 disposed on one surface of the lower substrate 4, and the upper substrate ( 2 shows a reflective liquid crystal display device including a polarizing plate 32 attached to one surface of 2) and a focusing plate 16 formed on one surface of the polarizing plate 32.

The polarizing plate 32 is a film that transmits only the light vibrating in parallel with any one axis among the light vibrating in various directions. The polarizing plate generally adsorbs a dye having a high anisotropy or dichroism to polyvinyl alcohol (PVA). A polymer membrane made by arranging urea molecules or dye molecules through stretching, wherein the stretching direction is a absorption axis and a direction perpendicular to the absorption axis forms a polarization axis so that only light passing through the polarization axis is transmitted through light that vibrates in an arbitrary direction. do.

The polarizing plate 32 having this function can be simultaneously attached to the outer surface of the upper substrate 2 or the outer surface of the lower substrate 4 or the outer surfaces of the upper substrate 2 and the lower substrate 4 according to the characteristics of the liquid crystal display device. In addition, the focusing plate 16 attached to one surface of the polarizing plate 32 in contact with the external light has the same structure and function as the four embodiments described in the first embodiment of the present invention.

12 is a schematic cross-sectional view of a reflective liquid crystal display device according to a fourth embodiment of the present invention, wherein the pixel electrodes 6 and the pre-scan 8 electrodes are disposed on opposite surfaces inside the substrates 2 and 4. And a liquid crystal cell 36 having an alignment liquid crystal LC, a phase difference compensation film 34 formed on one surface of the upper substrate 2, and a polarizing plate attached to one surface of the phase difference compensation film 34. 32, a focusing plate 16 disposed on one surface of the polarizing plate 32 in contact with the external light, and a reflecting plate 12 formed on one surface of the lower substrate 4. have.

The liquid crystal LC used in the liquid crystal display device has a characteristic of birefringence inherent in the liquid crystal, that is, a refractive index in the long axis direction and a short axis direction are different from each other. Is generated.

Therefore, in order to compensate for the viewing angle phenomenon, the retardation compensation film 34 is attached to one surface of the upper substrate 2. The retardation compensation film 34 is made of a polymer material such as polycarbonate in the form of a film and then stretched. In order to have a suitable phase difference in the film, the polymer constituting the phase difference compensation film 34 has a shape stacked obliquely in the horizontal or vertical direction.

Accordingly, the phase change of the retardation compensation film 34 has the same magnitude and the opposite direction as the phase change in the liquid crystal LC, so that they are compensated for each other to compensate for the phase change in the liquid crystal LC.

The retardation compensation film 34 is attached to one surface of the upper substrate 2 or one surface of the lower substrate 4. When the retardation compensation film 34 is attached to one surface of the lower substrate 4, the reflection plate 12 is applied. ) Should be attached to the bottom surface of the retardation compensation film 34.

And the focusing plate 16 attached to one surface of the polarizing plate 32 in contact with the external light has the same structure and operation as the four embodiments described in the first embodiment of the present invention.

The formation of the converging plate 16 provided on one surface of the substrate 2 or the polarizing plate 32 in contact with the external light to inject most of the external light in a direction more perpendicular to the reflecting plate 12 is usually performed by a chemical etching process or a machine. It can be formed through a conventional injection process, the attachment of the focusing plate 16 can be attached by a conventional transparent adhesive.

As described above, the majority of the external light incident at various angles through the focusing plate 16 is focused in a direction more perpendicular to the reflecting plate 12 to improve the vertical incident rate of the external light, so that the incident light has a predetermined inclination. By minimizing the factor that most of the light is scattered or diffusely reflected in the reflector 12 can improve the vertical reflectance of the liquid crystal display device.

Therefore, the luminance in the region where the user is located is further improved, thereby realizing a better reflection type liquid crystal display device.

As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it is within the scope of the present invention.

As described above, the present invention provides a vertical incidence means, which reflects most of the external light incident on the substrate and the liquid crystal cell in a direction more perpendicular to the reflection plate, thereby increasing the reflection efficiency of the reflection plate, thereby realizing improved luminance. It is possible to provide a display device.

Claims (23)

Two transparent substrates arranged in parallel at predetermined intervals; A liquid crystal cell comprising an alignment film and liquid crystal injected between the alignment films on electrodes formed on opposite surfaces of the substrate; A reflection plate installed on one surface of one of the substrates to reflect external incident light; And a vertical incidence means provided on one of the substrates to which external incident light is incident to focus the external incident light onto the reflecting plate, thereby improving vertical incidence of external incident light. The method of claim 1, wherein the vertical incidence means is arranged in a plurality of bent portions formed by continuously bending in one direction along the other direction on one surface facing the substrate, focusing a plurality of external light incident in at least two directions to the reflecting plate A reflective liquid crystal display device comprising a focusing plate. The reflective liquid crystal display of claim 2, wherein the curved portion of the focusing plate is sharply formed. The reflective liquid crystal display of claim 2, wherein the curved portion of the focusing plate is curved. The liquid crystal display of claim 2, wherein the focusing plate is made of a transparent polymer material. The reflection type liquid crystal display device of claim 2, wherein the focusing plate further comprises a polymer film having a refractive index lower than its refractive index in a space formed between each curved portion. The method of claim 1, wherein the vertical incidence means is formed by forming a plurality of polygonal portions in which a polygonal structure having at least three surfaces or more in succession facing a substrate, focusing a large number of external light incident in at least three directions to the reflecting plate A reflective liquid crystal display device comprising a focusing plate. The reflective liquid crystal display of claim 7, wherein the polygonal portions of the focusing plate are formed by combining a plurality of square pyramids in a predetermined pattern. 8. The reflective liquid crystal display of claim 7, wherein the polygonal portion of the focusing plate is formed by combining a plurality of cones in a predetermined pattern. The liquid crystal display device of claim 7, wherein the focusing plate is made of a transparent polymer material. The liquid crystal display device of claim 7, wherein the focusing plate further comprises a polymer film having a refractive index lower than its refractive index in the space formed between the polygonal portions. Two transparent substrates arranged in parallel at predetermined intervals; A liquid crystal cell comprising an alignment film and liquid crystal injected between the alignment films on electrodes formed on opposite surfaces of the substrate; A reflection plate installed on one surface of one of the substrates to reflect external incident light; A polarizing plate provided on at least one of the substrates and selectively transmitting only external incident light in a constant vibration direction; And a vertical incidence means provided at the side of the substrate or the polarizing plate on which the external incident light is incident to focus the external incident light on the reflecting plate to improve the vertical incidence ratio of the external incident light. The reflection type liquid crystal display device of claim 12, further comprising a phase difference compensation film for correcting a phase change according to a viewing angle on at least one of the substrates. The reflecting plate of claim 12, wherein the vertical incidence means comprises a plurality of bent portions that are continuously bent from one direction along the other direction to one surface facing the substrate or the polarizing plate, and the plurality of external light incident in at least two directions is disposed on the reflecting plate. A reflection type liquid crystal display device comprising a focusing plate for focusing with light. The liquid crystal display of claim 14, wherein the curved portion of the focusing plate is sharply formed. 15. The reflective liquid crystal display of claim 14, wherein the curved portion of the focusing plate is curved. The reflective liquid crystal display of claim 14, wherein the focusing plate is made of a transparent polymer material. The reflection type liquid crystal display device of claim 14, wherein the focusing plate further comprises a polymer film having a refractive index lower than its refractive index in a space formed between the curved portions. The method of claim 12, wherein the vertical incidence means is formed by forming a plurality of polygonal portions in which a polygonal structure having at least three surfaces or more continuously formed on one surface facing the substrate or a polarizing plate, the majority of the external light incident in at least three directions A reflection type liquid crystal display device comprising a focusing plate focused on a reflecting plate. The reflective liquid crystal display of claim 19, wherein the polygonal portion of the focusing plate is formed by combining a plurality of square pyramids in a predetermined pattern. 20. The reflective liquid crystal display of claim 19, wherein the polygonal portion of the focusing plate is formed by combining a plurality of cones in a predetermined pattern. 20. The reflective liquid crystal display of claim 19, wherein the focusing plate is made of a transparent polymer material. 20. The reflective liquid crystal display device of claim 19, wherein the focusing plate further comprises a polymer film having a refractive index lower than its refractive index in a space formed between the polygonal portions.

Images