KR19980026471A - LCD and its manufacturing method - Google Patents

Abstract

Disclosed are an improved liquid crystal display device and a method for manufacturing the spacer and the method for manufacturing the spacer for maintaining a uniform space between the liquid crystal injection. The liquid crystal display device includes a front plate and a rear plate which are installed to face each other to form a closed space into which liquid crystal is injected, and the rear plate is formed with a plurality of protrusions so that the front plate and the rear plate maintain a predetermined distance. An electrode layer formed in a predetermined pattern on mutually opposing surfaces of the and back plates, an alignment film formed on the top surfaces of the front and back plates, respectively, and an upper polarizing plate and a lower polarizing plate provided on the outside of the front and back plates, respectively, And liquid crystal injected into the closed space between the plate and the back plate. Since the liquid crystal display device and the manufacturing method thereof are fixed in place without moving the spacer, the gap between the upper and lower substrates can be kept constant, and the spacer can be selectively formed in a desired shape at a desired position. The display quality can be improved, and the device manufacturing process can be simplified and the cost can be reduced.

Description

LCD and its manufacturing method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a liquid crystal display device and a method of manufacturing the improved structure and manufacturing method of a spacer for maintaining a uniform space between liquid crystals.

The liquid crystal display device is not a device that emits light by itself such as a CRT, a light emitting diode, and a light emitting display tube, but is a light receiving type device that receives light from the outside and becomes visible as a print.

These liquid crystal display elements have extremely low power consumption compared to other display elements, and can be produced in various sizes from the smallest to the largest. They can be diversified in display type, can operate at low voltage, and are extremely easy to interface with the integrated circuit. It is characterized by.

In general, liquid crystal display devices, which are widely used as display devices of low power consumption type characters and graphics, have become larger in recent years so that a large amount of information can be displayed on one screen.

As the liquid crystal display device becomes larger and larger in size as described above, it has occupied a very important position in the field of display devices. On the other hand, the precise internal structure of the liquid crystal display device requires precise control of the manufacturing process.

1 and 2 illustrate an example and another example of a conventional liquid crystal display device.

Referring to FIG. 1, a conventional liquid crystal display device 10 includes a front plate 12 and a back plate 12 ′ which are installed to face each other and form a closed space therein, and the front plate 12 and the back plate ( The liquid crystal molecules are oriented in a predetermined direction on the upper surfaces of the electrode layers 13 and 13 'formed on the opposite surfaces of the surface 12' in a predetermined pattern, and the front plate 12 and the back plate 12 'on which the electrode layers are formed. The alignment layers 14 and 14 ', respectively, to be formed on the outer side of the front plate 12 and the back plate 12', and the front plate 12 and the back plate ( The liquid crystal 16 is injected into the closed space between the 12 ') and the spacer 15 is provided to maintain a constant distance between the front plate 12 and the back plate 12'. In addition, the spacer 15 is a spherical spacer, which is randomly distributed and distributed on a substrate to maintain a gap of the closed space.

In the conventional plastic liquid crystal display device 10 having such a configuration, the front plate 12 and the back plate 12 'are made of a flexible plastic, so that a spacer 15 is disposed between the front plate and the back plate. There is a possibility of moving to one side. Therefore, a problem arises that the distance between the front plate 12 and the back plate 12 'cannot be kept uniform over the entire surface of the substrate. In addition, the density of the spacers must be increased in order to allow the device to withstand mechanical shocks from the outside. Such a randomly distributed spacer has a high possibility of acting as a defect in the pixel portion, thereby degrading the display function of the device. There was this. In addition, when the liquid crystal is vacuum-injected in the liquid crystal injection process, the substrate is strongly compressed by the pressure difference between the inside and the outside of the substrate. The pressing force causes a problem that the plastic substrate is easily deformed and the alignment film and the conductive film are damaged. .

Figure 2 shows another example of a conventional liquid crystal display device for solving such a problem. Referring to FIG. 2, the liquid crystal display device 20 has the same configuration except for the liquid crystal display device 10 and the spacer shown in FIG. 1. That is, the liquid crystal display device 20 is provided with a front plate 22 and a back plate 22 'which are provided to face each other and form a closed space therein, and the front plate 22 and the back plate 22' of each other. In order to align the liquid crystal molecules in predetermined directions on the opposite surfaces of the electrode layers 23 and 23 'formed in a predetermined pattern on the opposite surface, and the front plate 22 and the back plate 22' on which the electrode layers are formed, respectively. Between the alignment films 24 and 24 ', the polarizing plates 21 and 21' attached to the outside of the front plate 22 and the back plate 22 ', and between the front plate 22 and the back plate 22'. Liquid crystal 26 is injected into the closed space of the spacer and the spacer 25 is provided to maintain a constant distance between the front plate 22 and the back plate 22 '. The spacer 25 is formed of a plastic rod provided at a portion other than the pixel, that is, at a portion where the electrode layers 23 and 23 'are not formed. In order to form such a spacer, a fine rod-shaped spacer may be formed and attached to a substrate, or the substrate may be selectively etched to leave a spacer in a non-pixel portion, or a photosensitive resin may be applied onto the substrate, followed by photolithography. To leave the spacer part and remove the other part.

However, it is difficult to form the liquid crystal display device having such a spacer, and the defect rate is high at the time of manufacturing the substrate, resulting in a rise in the cost of forming the spacer.

The present invention was created in order to solve the above problems, and the structure and the process are improved so that the space into which the liquid crystal is injected can be maintained at a constant interval, which is resistant to impact from the outside, and the process for forming the spacer is easy. It is an object of the present invention to provide a liquid crystal display device and a method of manufacturing the same.

1 is a view showing an example of a conventional liquid crystal display device, Figure 1a is a schematic cross-sectional view and Figure 1b is a perspective view,

2 is a view showing another example of a conventional liquid crystal display device, FIG. 2A is a schematic cross-sectional view and FIG. 2B is a perspective view;

3 is a schematic cross-sectional view of an embodiment of a liquid crystal display device according to the present invention;

4 is a schematic cross-sectional view of another embodiment of a liquid crystal display device according to the present invention;

5 is a conceptual view showing an embodiment of a method of manufacturing a liquid crystal display device according to the present invention;

6 is a conceptual view showing another embodiment of the method of manufacturing a liquid crystal display device according to the present invention.

* Explanation of symbols on the main parts of the drawings *

32,42 upper polarizer 32 ', 42' lower polarizer

33,41 ... Front plate 33 ', 41' ... Back plate

34,34 ', 43,43' ... barrier layer 35,35 ', 44,44' ... electrode layer

36,36 ', 45,45' ... Alignment film 37,46 ... Liquid crystal

The liquid crystal display device according to the present invention for achieving the above object is provided with a front plate and a back plate which are installed to face each other so as to form a closed space in which the liquid crystal is injected, the front plate and the back plate is a predetermined A plurality of protrusions are formed to maintain a gap, and the liquid crystal molecules are formed in predetermined directions on an electrode layer formed in a predetermined pattern on opposite surfaces of the front plate and the back plate, and on an upper surface of the front plate and the back plate on which the electrode layers are formed. And a liquid crystal injected into a closed space between the front plate and the back plate, and an alignment film formed to align the structure, the upper polarizing plate and the lower polarizing plate respectively provided outside the front plate and the back plate. do.

And the front plate and the back plate is composed of an optically isotropic film made of a plastic material, it is preferable that the barrier layer is formed on each of the opposite surface of the front plate and the back plate is further provided.

It is preferable that the said back plate is a crimping member in which the some processus | protrusion was formed in the site | part in which the said electrode layer is not formed.

It is preferable to coat an adhesive on top of the plurality of protrusions.

The liquid crystal is preferably composed of a nematic liquid crystal.

The liquid crystal is preferably composed of a ferroelectric liquid crystal.

It is preferable that the said liquid crystal consists of a mixture of a polymer and a liquid crystal.

It is preferable that a reflecting plate provided outside the lower polarizing plate is further provided.

In addition, the liquid crystal display device according to the present invention for achieving the above object is provided with an upper polarizing plate and a lower polarizing plate facing each other to form a closed space in which the liquid crystal is injected, the lower polarizing plate is the upper polarizing plate and the lower polarizing plate A plurality of protrusions are formed to maintain a predetermined interval, and the liquid crystal molecules are formed on upper surfaces of the upper polarizing plate and the lower polarizing plate having electrode layers formed in a predetermined pattern on opposite surfaces of the upper and lower polarizing plates, respectively. And a liquid crystal injected into a closed space between the upper polarizing plate and the lower polarizing plate, and an alignment film formed to orientate in the direction of?, A substrate respectively provided outside the upper polarizing plate and the lower polarizing plate.

And the front plate and the back plate is made of a plastic film, it is preferable that the barrier layer is formed on each of the opposite surface of the upper polarizing plate and the lower polarizing plate is further provided.

The lower polarizing plate is preferably a molding member having a plurality of protrusions formed at a portion where the electrode layer is not formed.

It is preferable to coat an adhesive on top of the plurality of protrusions.

The liquid crystal is preferably composed of a nematic liquid crystal.

The liquid crystal is preferably composed of a ferroelectric liquid crystal.

It is preferable that the reflector is further provided on the outside of the lower polarizing plate.

In addition, the manufacturing method of the liquid crystal display device according to the present invention for achieving the above object, the step of pressing-molding the back plate so that a plurality of projections are formed in the non-electrode layer of the back plate made of a plastic film, the front plate And sequentially forming a barrier layer, an electrode layer, and an alignment layer, respectively, on the top surface of the back plate, and combining the front plate and the back plate to face each other so as to be formed between the front plate and the back plate. Forming a closed space maintained at a predetermined height, injecting liquid crystal into the closed space, and attaching polarizers to the outside of the front plate and the back plate, respectively.

And it is preferable to further have a step of coating an adhesive on the top of the projection of the back plate.

In addition, the manufacturing method of the liquid crystal display device according to the present invention for achieving the above object, the step of forming the lower polarizing plate so that a plurality of projections are formed in the non-electrode layer of the lower polarizing plate, the upper polarizing plate and the lower polarizing plate Sequentially forming a barrier layer, an electrode layer, and an alignment layer, respectively, on an upper surface thereof, and combining the upper polarizing plate and the lower polarizing plate so as to face each other, being formed between the upper polarizing plate and the lower polarizing plate and having a predetermined height by the plurality of protrusions. Forming a maintained closed space, injecting a liquid crystal into the closed space, and attaching a plastic substrate to the outer side of the upper polarizing plate and the lower polarizing plate, respectively.

And it is preferable to further have a step of coating an adhesive on the top of the projection of the lower polarizing plate.

Hereinafter, a preferred embodiment of a liquid crystal display device and a method of manufacturing the same according to the present invention with reference to the accompanying drawings will be described in detail.

3 illustrates an embodiment of a liquid crystal display device according to the present invention.

Referring to FIG. 3, the liquid crystal display device 30 includes a front plate 33 and a back plate 33 ′ which are installed to face each other to form a closed space into which liquid crystal is injected, and the front plate 33 and the back plate 33. ') Liquid crystal molecules are aligned in a predetermined direction on the upper surfaces of the electrode layers 35 and 35' formed in a predetermined pattern on the mutually opposite surfaces of the ') and the front plate 33 and the back plate 33' on which the electrode layers are formed. Each of the alignment layers 36 and 36 'formed so as to be provided, the upper polarizing plate 32 and the lower polarizing plate 32' which are respectively provided on the outer side of the front plate 33 and the rear plate 33 ', and the front plate ( The liquid crystal 37 injected into the closed space between the 33 and the back plate 33 'is provided.

When the liquid crystal display device 30 is a plastic LCD, the front plate 33 and the back plate 33 'are made of an optically isotropic film made of a plastic material, and the front plate 33 and the back plate 33 Barrier layers 34 and 34 'are formed on opposite surfaces of').

The back plate 33 'is provided with a plurality of protrusions 33'a so as to maintain a constant distance between the back plate 33' and the front plate 33, which functions as a spacer. In order to make the protrusion 33'a, a plastic substrate is formed, and the protrusions 33'a are selectively formed at a desired position of a portion where the electrode layer 35 'is not formed on the substrate. In addition, the shape of the projection 33'a can be a variety of shapes, such as cylindrical, elliptic cylinder, hexahedral dot shape, cuboid rod shape, these shapes in consideration of ease of design, positional relationship with other parts, etc. Will be decided.

An adhesive (not shown) is coated on top of the plurality of protrusions 33 ′ a to increase adhesiveness.

Reference numerals 31 and 31 ′ in the drawings are polarizer protective plates.

4 illustrates another embodiment of a liquid crystal display device according to the present invention.

Referring to FIG. 4, the liquid crystal display device 40 includes an upper polarizing plate 42 and a lower polarizing plate 42 ′ disposed to face each other so as to form a closed space into which liquid crystal is injected, and the upper polarizing plate 42 and the lower polarizing plate 42. Liquid crystal molecules are oriented in a predetermined direction on the electrode layers 44 and 44 'formed in a predetermined pattern on opposite surfaces of') and on the upper surfaces of the upper polarizing plate 42 and the lower polarizing plate 42 'on which the electrode layers are formed. The alignment layers 45 and 45 ', respectively, and the substrates 41 and 41' respectively provided outside the upper polarizing plate 42 and the lower polarizing plate 42 ', and the upper polarizing plate 42 and the lower polarizing plate. The liquid crystal 46 is injected into the closed space between the 42 '.

In the case where the liquid crystal display device 40 is a plastic LCD, the substrates 41 and 41 'are made of a plastic film, and barriers are provided on opposite surfaces of the upper polarizing plate 42 and the lower polarizing plate 42', respectively. Layers 43 and 43 'are formed, respectively. In this embodiment, the plastic substrates 41 and 41 'may not be optically isotropic.

The lower polarizing plate 42 'is formed as a molding member, and a plurality of protrusions 42'a are selectively formed at a portion where the electrode layer 44' is not formed. The protrusion 42'a functions as a spacer for keeping the gap between the liquid crystal injection spaces, and the protrusion may have various shapes such as a cylindrical shape, an elliptic cylinder shape, a hexahedral dot shape, and a rectangular bar shape. In determining the shape of the projections, the ease of design and the positional relationship with other parts shall be taken into account.

And an adhesive (not shown) is coated on the top of the plurality of protrusions 42'a to increase the adhesion.

The present invention is not limited to the plastic LCD described so far. Therefore, the above-described features can be implemented in the liquid crystal display device as described above without departing from the scope of the present invention.

1) TN-LCD (twisted nematic); The liquid crystals 37 and 46 in FIGS. 3 and 4 are constituted by nematic liquid crystals. The liquid crystal display device injects nematic liquid crystals with positive dielectric anisotropy between two ITO glass substrates and arranges them so that the molecular arrangements of the two substrate surfaces are perpendicular to each other. A 90 degree contiguous twisted array is formed. On the other hand, it is naturally applicable to the liquid crystal display device having a super twisted nematic (STN) mode.

2) FLCD (ferroelectric): The liquid crystals 37 and 46 in Figs. 3 and 4 are composed of ferroelectric liquid crystals. The liquid crystal display device utilizes a change in the arrangement direction of liquid crystal molecules in a direction parallel to the electrodes due to the interaction between the spontaneous polarization of the ferroelectric liquid crystal and the electric field.

3) Polymer / Liquid Crystal Composite; The liquid crystal 36 in FIG. 3 is composed of a mixture of polymer and liquid crystal. This liquid crystal display element uses a mixture of a liquid crystal and a polymer, and displays by adjusting scattering and reflection by application of voltage. Since the polarizing plates 32 and 32 'are not necessary, the process can be simplified and a display with good light efficiency can be realized.

4) reflective liquid crystal display device; 3 and 4, reflectors are provided outside the lower polarizing plates 32 'and 42'.

FIG. 5 illustrates an embodiment of a method of manufacturing a liquid crystal display device according to the present invention, and is a process diagram of manufacturing the liquid crystal display device 30 shown in FIG. 3.

5A and 5B, in order to manufacture the liquid crystal display device 30, a back plate 33 ′ made of an optically isotropic plastic film is first molded into a predetermined shape. The projections 33'a produced by this molding are selectively made in plural so as to be located at the non-electrode layer portion of the substrate.

Then, as shown in FIGS. 5C, 5D, and 5E, the barrier layer 34 ', the electrode layer 35', and the alignment layer 36 'are sequentially formed on the upper surface of the molded back plate 33'. do.

As shown in FIG. 5F, the barrier layer 34, the electrode layer 35, and the alignment layer 36 are sequentially formed on the front plate 33 made of an uncompressed plastic film.

And as shown in Figure 5g, the front plate 33 and the back plate 33 'by opposing to each other to create a closed space in which the liquid crystal can be injected. In this case, the blocking space formed between the front plate 33 and the back plate 33 'may be maintained at a predetermined height by the plurality of protrusions 33'a.

Next, as shown in FIG. 5H, the liquid crystal 37 is injected into the closed space, and the polarizing plates 32 and 32 ′ are attached to the outside of the front plate 33 and the back plate 33 ′, respectively. 30 is completed.

Meanwhile, the adhesive may be further improved by coating an adhesive on the top of the protrusion 33'a of the back plate 33 '.

FIG. 6 illustrates another embodiment of a method of manufacturing a liquid crystal display device according to the present invention, which is a process diagram of manufacturing the liquid crystal display device 40 shown in FIG. 4.

As shown in FIGS. 6A and 6B, in order to manufacture the liquid crystal display device 40, first, the lower polarizing plate 42 ′ is formed into a predetermined shape to form a plurality of protrusions 42 ′ a. In this case, the protrusion 42'a is selectively formed to be located at the non-electrode layer portion of the substrate.

Then, as shown in FIGS. 6C, 6D, and 6E, the barrier layer 43 ', the electrode layer 44', and the alignment layer 45 'are sequentially formed on the upper surface of the lower polarizing plate 42' which is press-molded. do.

As shown in FIG. 6F, the barrier layer 43, the electrode layer 44, and the alignment layer 45 are sequentially formed on the unmolded upper polarizing plate 42.

As shown in FIG. 6G, the upper polarizing plate 42 and the lower polarizing plate 42 ′ are opposed to each other to form a closed space in which liquid crystal can be injected. In this case, the blocking space formed between the upper polarizing plate 42 and the lower polarizing plate 42 'may be maintained at a predetermined height by the plurality of protrusions 42'a.

Then, as shown in FIG. 6H, the liquid crystal 46 is injected into the closed space, and the substrates 41 and 41 'are made of plastic films on the outer sides of the upper polarizing plate 42 and the lower polarizing plate 42', respectively. By attaching the liquid crystal display device 40, the liquid crystal display device 40 is completed.

On the other hand, including the step of coating an adhesive on the top of the projection 42'a of the lower polarizing plate can further improve the adhesion.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the technical protection scope of the present invention should be defined by the technical spirit of the claimed claims.

The liquid crystal display device and its manufacturing method as described above has the following advantages.

First, since the spacer of the liquid crystal display is not moved and fixed in place, there is no fear of biasing it to one side. When using a plastic substrate, the distance between the upper and lower substrates can be kept constant, and the impact resistance when used is Is improved.

Second, since the spacers of the liquid crystal display device may be selectively formed at a desired position (in a portion other than the pixel) without being randomly dispersed, the display quality of the device may be improved.

Third, defects caused by deformation of the substrate during liquid crystal injection can be reduced.

Fourth, since the spacers can be formed without steps such as a photolithography process or an etching process, the liquid crystal display device manufacturing process can be simplified and the cost can be reduced.

Claims (19)

A front plate and a rear plate provided to face each other so as to form a closed space into which liquid crystal is injected; a plurality of protrusions are formed on the rear plate so that the front plate and the rear plate maintain a predetermined distance, An electrode layer formed in a predetermined pattern on opposite surfaces of the front plate and the back plate, respectively; An alignment layer formed on the upper surface of the front plate and the back plate on which the electrode layer is formed to align the liquid crystal molecules in a predetermined direction; An upper polarizing plate and a lower polarizing plate respectively installed outside the front plate and the rear plate; And a liquid crystal injected into the closed space between the front plate and the back plate. The method of claim 1, The front plate and the back plate is composed of an optically isotropic film made of a plastic material, And a barrier layer formed on opposite surfaces of the front plate and the back plate, respectively. The method according to claim 1 or 2, And the back plate is a press-molded member having a plurality of protrusions formed at a portion where the electrode layer is not formed. The method of claim 1, Liquid crystal display device characterized in that the adhesive is coated on the top of the plurality of projections. The method according to any one of claims 1 to 4, And the liquid crystal is composed of a nematic liquid crystal. The method according to any one of claims 1 to 4, And the liquid crystal comprises a ferroelectric liquid crystal. The method according to any one of claims 1 to 4, And the liquid crystal is composed of a mixture of polymer and liquid crystal. The method according to any one of claims 1 to 4, The liquid crystal display device further comprises a reflection plate provided outside the lower polarizing plate. An upper polarizing plate and a lower polarizing plate disposed to face each other so as to form a closed space into which liquid crystal is injected, and the lower polarizing plate is provided with a plurality of protrusions so that the upper polarizing plate and the lower polarizing plate maintain a predetermined interval; An electrode layer formed in a predetermined pattern on surfaces of the upper polarizer and the lower polarizer, respectively; An alignment layer formed on the upper surface of the upper polarizing plate and the lower polarizing plate on which an electrode layer is formed to align liquid crystal molecules in a predetermined direction; A substrate provided outside the upper polarizing plate and the lower polarizing plate, respectively; And a liquid crystal injected into a closed space between the upper polarizing plate and the lower polarizing plate. The method of claim 9, The front plate and the back plate are made of a plastic film, And a barrier layer formed on opposite surfaces of the upper polarizing plate and the lower polarizing plate, respectively. The method of claim 9 or 10, And the lower polarizing plate is a compression molding member having a plurality of protrusions formed at a portion where the electrode layer is not formed. The method of claim 9, Liquid crystal display device characterized in that the adhesive is coated on the top of the plurality of projections. The method according to any one of claims 9 to 12, The liquid crystal is a liquid crystal display device, characterized in that composed of a nematic liquid crystal (nematic), The method according to any one of claims 9 to 12, And the liquid crystal comprises a ferroelectric liquid crystal. The method according to any one of claims 9 to 12, The liquid crystal display device further comprises a reflection plate provided outside the lower polarizing plate. Shaping the back plate such that a plurality of protrusions are formed on a portion of the non-electrode layer of the back plate made of a plastic film, Sequentially forming a barrier layer, an electrode layer, and an alignment layer on the upper surface of the front plate and the back plate, respectively; Coupling the front plate and the back plate to face each other to form a closed space formed between the front plate and the back plate and maintained at a predetermined height by the plurality of protrusions; Injecting liquid crystal into the closed space; Method for manufacturing a liquid crystal display device comprising the step of attaching a polarizing plate on the outside of the front plate and the back plate, respectively, The method of claim 16, Liquid crystal display device further comprising the step of coating an adhesive on the top of the projection of the back plate. Shaping the lower polarizing plate such that a plurality of protrusions are formed on a portion of the non-electrode layer of the lower polarizing plate; Sequentially forming a barrier layer, an electrode layer, and an alignment layer on the upper surface of the upper polarizing plate and the lower polarizing plate, respectively; Coupling the upper polarizing plate and the lower polarizing plate to face each other, forming a closed space formed between the upper polarizing plate and the lower polarizing plate and maintained at a predetermined height by the plurality of protrusions; Injecting liquid crystal into the closed space; Method of manufacturing a liquid crystal display device comprising the step of attaching a plastic substrate on the outer side of the upper and lower polarizing plate, respectively, The method of claim 18, Liquid crystal display device further comprising the step of coating an adhesive on the top of the projection of the lower polarizing plate.