CN1768293A - Liquid crystal display with internal polarizer - Google Patents

Abstract

A liquid crystal display is provided comprising a front panel (103), a rear panel, and a liquid crystal layer placed between the front and rear panels (106). At least one of the front and rear panels comprises an internal polarizer (301) situated between an electrode (104) and a substrate (103) in the panel. The internal polarizer is made of a highly temperature durable material that is chemically stable at an elevated temperature of at least 150 DEG C.

Description

LCD display with internal polarizer

related application

This application claims priority to U.S. Application No. 10/656,516, filed September 4, 2003, which claims U.S. Provisional Patent Application entitled "LIQUID CRYSTAL DISPLAY WITHINTERNAL POLARIEZR," filed April 9, 2003 Priority No. 60/461,686, both applications are hereby incorporated by reference in their entirety.

technical field

The present invention relates to liquid crystal displays and related devices, and more particularly, to liquid crystal displays with polarizers.

Background technique

In the early 1970s, liquid crystals were first used as a basic material for devices that display visual information. The low power consumption and small size of these devices compared to other types of similarly functional systems has made LCDs rapidly becoming an indispensable part of portable and mobile devices. Subsequent developments in liquid crystal technology have demonstrated the ability of these devices to display high-quality color graphics images while maintaining the advantages of small size, light weight, low power consumption, and relatively low price. The combination of these properties makes liquid crystal displays widely used. Currently, liquid crystal displays have been used in virtually all technical fields, including displays for portable computers, calculators, and related equipment; control display panels for portable and small instruments and sensors; mobile and portable household appliances and related equipment (such as mobile phones) , notebooks, e-books, notepads, and electronic watches); projection devices and large screens for cinemas, exhibition halls, public places and events, etc.

Liquid crystal displays have been known since the late 1970s, and "Reflective Liquid Crystal Displays" by S.-T.Wu and D.-K. Yang, published by Wiley in 2001, and by Wiley in 2001 The device structure is described in full detail in "Liquid Crystal Displays: Addressing Schemes and Electro-Optical Effects" by E. Lueder, published by E. Lueder. The structure of a liquid crystal display consists of a system of multiplanar layers that perform various functions.

At least two types of liquid crystal displays can be distinguished: reflective and transmissive. The two types differ in the way light travels through the various layers of the LCD. In reflective LCDs, light enters the structure, is reflected by the reflective layer, and exits the same side. In a transmissive LCD, light enters the structure from one side, travels through the system, and exits the opposite side.

In practice, however, the difference between these two types of LCDs is related to the use of external light sources or lighting systems. The illumination system can generally be any light source that provides uniform transmitted illumination of the liquid crystal display layer.

In reflective LCDs, there can be no lighting system: this type of LCD uses light from surrounding light sources. The function of the reflective layer is to reflect light from these light sources towards the viewer. Such LCD monitors are often also equipped with an internal front lighting system to ensure that the monitor operates in the dark.

In transmissive liquid crystal displays, illumination is provided by an external light source that transmits the illumination of the system from the rear side. This situation is called a backlight system.

In addition to these two main types of liquid crystal displays, there are also devices that combine these two principles. Such displays are called transflective or transreflective. This combination is achieved by incorporating a translucent reflective layer and a backlight source into a reflective liquid crystal display.

When describing an LCD display, it is best to distinguish between the front side and the back side. The front side is the side facing the viewer, and the back side is the side opposite to the front side. The layers located before or after the liquid crystal layer in the liquid crystal display structure are usually referred to as the front layer and the rear layer, respectively. For example, there are rear and front substrates, rear and front electrodes, etc. The layers before the liquid crystal layer in the liquid crystal display structure are often referred to as the front panel, while the layers after the liquid crystal layer are referred to as the rear panel.

The light flux from the backlight system is regulated by the structure of the liquid crystal display to generate an image on the display. In addition to the reflection layer and the light source, the image is also controlled by the functional layer of the liquid crystal and at least one polarizer.

The working principle of a liquid crystal display is based on controlling the polarization state of light (polarized by one of a plurality of polarizers) in a liquid crystal by a voltage applied to electrodes.

Depending on the type of liquid crystal display (reflective or transmissive), the functional sequence of polarizers and liquid crystal layers can be as follows.

In a reflective LCD, after the front polarizer is the liquid crystal and reflective layer. In order to increase the contrast of a liquid crystal display, a second polarizer is usually introduced between the liquid crystal and the reflective layer. As mentioned above, light from an ambient light source or a front lighting system passes through the LCD structure twice: from the front side to the reflective layer and back to the viewer.

In a transmissive LCD, the front polarizer is followed by a liquid crystal and a rear polarizer. Here, light passes through the LCD structure in only one direction (from the backlight system to the viewer), so a second polarizer is required.

In a transflective liquid crystal display, the front polarizer is followed by a liquid crystal layer, a rear polarizer, and a translucent reflective layer. In this scheme, there must also be a rear polarizer.

The polarizer layer is usually applied on the outer surface of the front substrate, which is usually related to the characteristics of the liquid crystal display and the manufacturing process of the polarizer. In this case, the polarizer is called an external polarizer. In liquid crystal display projection devices, the polarizer is of the prism type. The large size and considerable energy consumption dictate that such polarizers be arranged externally.

In the case of sheet polarizers, the external arrangement has several disadvantages. An additional protective layer is required to prevent damage to the polarizer from external mechanical factors (scratches, impacts). Color filters used to form images on color liquid crystal displays depolarize transmitted light. In this case, the polarizer helps to eliminate this depolarization, but this is not possible with systems that are external polarizers. And because of the relatively large substrate thickness, the use of external polarizers significantly increases the optical path in the LCD structure, which results in loss of brightness and contrast and exacerbates image distortion at oblique viewing angles.

For LCDs with external polarizers located on the outside of the substrate, the substrate protects the internal layers from external elements and also often serves as the load-bearing part of the entire mechanical structure. For technical reasons, the substrate thickness is relatively large, so polarizers located outside the substrate significantly increase the optical path in the display. Relatedly, the main disadvantages of these display designs are the small viewing angle, sensitivity to mechanical action (related to the risk of damaging the external polarizer), and the extra layer required to protect the external polarizer (leading to strong parallax or image ghosting) The related manufacturing process is complex.

The aforementioned inherent drawbacks of liquid crystal displays with external polarizers have led to the invention of various methods for realizing liquid crystal displays with internal polarizers positioned between the substrates. All of the above approaches propose an arrangement where an internal polarizer layer is placed between the electrodes and the liquid crystal, and the functions of the polarizer and the alignment layer are combined in one layer.

US Patent No. 3,941,901 teaches a method of making internal polarizers for liquid crystal displays based on the alignment of long chains of vinyl polymers near the surface of the substrate. The process involves dissolving the polymer, applying the solution to the substrate, and creating shear strain as the layer thins. The solvent is then allowed to evaporate, leaving a thin layer of aligned polymer molecules on the substrate surface. It should be noted that by depositing such a layer on a substrate, and using polymers that behave as dichroic dyes, it is possible to obtain polarizers that simultaneously perform the function of an alignment layer.

US Patent No. 4,241,984 describes a liquid crystal display with an internal polarizer layer, wherein the polarizer with alignment properties performs dual functions of polarization and alignment. The combined polarization and alignment functions, the large capacitance and long switching times of the polarizers defined between the electrodes of the display structure, the relatively thick polarizers, and the degraded optical properties of the display make the fabrication process more complex and inflexible. Another disadvantage is that the liquid crystal layer is always oriented along the polarizer axis, making it impossible to perform modes of operation in these non-uniform orientations.

WO 9,739,380 describes a liquid crystal display with internal polarizers, in which a polarizer layer is generated instantaneously on a substrate using dichroic dye solutions in a lyotropic liquid crystal. One disadvantage of this liquid crystal display is that during the manufacturing process of the liquid crystal display, the polarizer layer needs to be generated instantaneously using a specific material applied by a specific equipment, which complicates the process and limits the choice of materials for the functional elements of the liquid crystal display .

A liquid crystal display with internal polarizers is described in US Patent No. 6,417,899 B1, in which a polarizing film is created on a special alignment layer between the electrodes and the substrate. The disadvantage of this solution is that in the manufacturing process of the liquid crystal display, a polarizing film needs to be formed instantaneously on the alignment layer, which makes the process complicated and the selection of polarizer materials is very limited.

Contents of the invention

It is therefore an object of the present invention to provide a liquid crystal display (LCD) with internal polarizers which overcomes the disadvantages of prior art LCDs, which include: high operating voltage, low multiplexing rate , chemical interaction may occur between the liquid crystal layer and the internal polarizer layer, and the manufacturing process is complicated.

These and other objects are achieved by a liquid crystal display of the present invention comprising a front panel, a rear panel, and a liquid crystal layer positioned between the front panel and the rear panel. At least one of the front and rear panels includes an internal polarizer positioned between the electrodes and the substrate in the same panel. The internal polarizer is made of a material that is chemically stable at elevated temperatures of at least 150°C.

Description of drawings

The present invention can be clearly understood from the following description in conjunction with the accompanying drawings, wherein:

Figure 1 (Prior Art) is a schematic diagram showing a liquid crystal display with an external polarizer;

Figure 2 (Prior Art) is a schematic diagram showing a liquid crystal display comprising two internal polarizers placed between a plurality of electrodes.

FIG. 3 is a schematic diagram illustrating a liquid crystal display including an internal polarizer disposed between an electrode and a substrate according to one embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating a reflective liquid crystal display according to an embodiment of the present invention.

FIG. 5 is a schematic diagram illustrating a transflective liquid crystal display according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a liquid crystal display including a reflective layer also serving as an electrode according to one embodiment of the present invention.

FIG. 7 is a schematic diagram illustrating a transmissive liquid crystal display according to an embodiment of the present invention.

Detailed ways

Herein, when the term "front" is used to describe substrates, electrodes, polarizers, transmission axes, and alignment directions, it means that the described elements are located on the viewer side of the liquid crystal.

Herein, when the term "rear" is used to describe substrates, electrodes, polarizers, transmission axes, and alignment directions, it means that the described elements are located on the side opposite to the viewer of the liquid crystal.

The present invention provides a liquid crystal display comprising at least one internal polarizer as well as electrodes, substrates and other functional layers. Internal polarizers are located between the electrodes and the substrate in the front panel, or between the electrodes and the substrate in the rear panel. In this embodiment, the substrate provides protection for the alignment layer and electrodes from external factors, thus reducing the operating voltage used to control the liquid crystal. The internal polarizer is fabricated from a refractory material (ie, a material that is chemically stable at elevated temperatures of at least 150°C).

The LCD manufacturing process includes multiple stages, requiring all layers in the panel to be resistant to high temperatures. These stages include: ITO sputtering treatment and polyimide baking. Indium tin oxide or ITO is a common material for electrodes in liquid crystal cells. Polyimide is a material used as an alignment layer of liquid crystal materials in LCD manufacturing. An additional protective layer can be used to protect the polarizer during the ITO etch process.

In one embodiment of the present invention, the layer structure of the liquid crystal display is as follows. The liquid crystal layer is sandwiched between a plurality of alignment layers in contact with the front and rear surfaces of the liquid crystal layer. Liquid crystals with adjacent alignment layers are located between the electrodes. At least one of the front or rear panels includes at least one internal polarizer made of high temperature resistant material, and the internal polarizer is located between the substrate and the electrodes.

In another embodiment of the invention, one of the front and rear panels has an internal polarizer in its functional layer, while the other panel has an external polarizer.

In another embodiment of the present invention, the transflective liquid crystal display may include at least two external polarizers in addition to the internal polarizers. According to the invention, at least one external polarizer is located on the same panel as the internal polarizer.

The outer polarizers of the present invention need not be made of high temperature resistant materials, although such materials can also be used to make the outer polarizers.

In another embodiment of the present invention, the internal polarizer does not cover the entire surface of the substrate. This design with partial internal polarizers can be used in some designs that combine the properties of both transmissive and reflective designs in one display.

There is no need for any other auxiliary layers between the electrodes and the polarizer and/or between the polarizer and the substrate, although for some special applications auxiliary layers can be provided if necessary.

According to the invention, the materials used for the polarizer and the auxiliary functional layer can be selected. The prior art LCD requires special materials for the polarizing film, and also requires special auxiliary layers and special manufacturing techniques. These factors complicate the polarizer process due to material constraints and the introduction of additional process operations.

The polarizers used in liquid crystal displays can be either flat plates with nonlinear optical properties or Taylor-Glan prism type devices. Taylor-Glan prism devices are commonly used in projection systems.

In one embodiment of the invention, the polarizer is Crystalline Film (TCF), available from Optiva, Inc., California, USA. The optically anisotropic dichroic crystal film has thin film thickness, low temperature sensitivity, highly anisotropic refractive index, and large dichroic ratio. These properties of TCF are related to the materials and methods used to make the membrane. Once the liquid crystal is applied to a suitable substrate, aligned, and then dried, the TCF of the present invention forms a specific molecular crystalline structure due to the crystallization of the liquid crystal phase. The liquid crystal phase includes at least one organic compound capable of forming a stable lyotropic liquid crystal phase or a thermotropic liquid crystal phase. The organic substance comprises at least one organic compound whose chemical formula includes (i) at least one ionic group to ensure dissolution in polar solvents for obtaining a lyotropic liquid crystal phase, and/or (ii) at least one non- Ionic groups, to ensure dissolution in non-polar solvents, for obtaining lyotropic liquid crystal phases, and/or (iii) at least one counterion, which may or may not remain in the molecular structure after film formation .

An optically anisotropic dichroic film comprises a supramolecular complex of a plurality of one or more organic compounds. These supramolecular complexes are oriented in specific ways to create the conductivity and polarization of transmitted light. The membrane comprises rod-shaped supramolecules comprising at least one discotic polycyclic organic compound having a conjugated π system. The film has a spherically ordered crystal structure with an intermolecular spacing of 3.4±0.3 Å along its polarization axis.

Selected for optically anisotropic dichroics based on the presence of expanded conjugated π-bonds in the conjugated aromatic ring and the presence of groups such as amines, phenols, ketones, etc. located in the molecular plane and attached to the conjugated bonds The basic material of crystal film. Molecules and/or molecular fragments have a planar structure. These basic materials are, for example, indanthrone (Var Blue 4), dibenzimidazole 1,4,5,8-naphthalene tetracarboxylic acid (Var Red 14), dibenzimidazole 3,4,9,10-perylenetetra Carboxylic acid, quinacridone (Pigment Violet 19), etc., their derivatives (or their mixtures) can form a stable lyotropic liquid crystal phase. When selecting materials for a TCF, the transmission spectrum of the film in the visible range can be considered. The use of dyes as initial compounds makes it possible to use crystal thin film polarizers as color temperature or neutrality filters and/or as UV or IR filters.

The colloidal lyotropic liquid crystal system formed is formed by the aggregation of molecules into supramolecular complexes constituting the kinetic unit of the system. These supramolecular complexes are oriented in specific ways to create the conductivity and polarization of transmitted light. WO 01/63346 describes a colloidal lyotropic liquid crystal system, the content of which is incorporated herein by reference. This colloidal lyotropic liquid crystal phase is largely the precursor of an ordered system from which optically anisotropic dichroic films in the solid state can be formed during the subsequent alignment of the supramolecular complex and solvent removal.

In an optically anisotropic dichroic film, at least in part of the film, the molecular planes are parallel to each other and the molecules form a three-dimensional crystal structure. Optimization of the fabrication process allows the formation of optically anisotropic dichroic single crystal films. The optical axis in this single crystal is perpendicular to the molecular plane. Such crystalline thin films are highly anisotropic and exhibit a high refractive index and/or high absorption coefficient in at least one direction.

Another important feature of optically anisotropic dichroic films is their high temperature resistance. In comparison, the thermal stability of iodine-type polarizers is generally limited to a maximum temperature of 80°C. For example, Bobrov, Y et al. held the 10th SID Symposium in Minsk, Belarus from September 18 to 21, 2001 (Proc.Of the 10 ^th SID Symposium, Minsk, Republic of Belarus, September 18-21, 2001, 23- 30) "Environmental and optical testing of OptivaThin Crystal Film ^TM Polarizers" published in "Advanced display technologies" and Abstracts of Technical Papers of Ignatov, L. et al., SID International Symposium, Long Beach, CA, May 16-18, 2000. In "Thin FilmPolarizers: Optical and Color Characteristics. Thermostability" published in Vol. As mentioned above, the optically anisotropic dichroic crystal film (OptivaTCF ^TM ) of the present invention manufactured by Optiva has high temperature resistance higher than 150°C. Recent studies have shown that the film is chemically stable up to 270 °C. The LCD manufacturing process requires relatively short exposures at temperatures of 200°C to 250°C, Optiva TCF ^TM enables internal polarizers in LCDs and makes them suitable for stages where ITO sputtering and/or PI baking is performed .

Colloidal systems can be mixed, which leads to the formation of complex supramolecules to provide crystal films with intermediate optical properties. In an optically anisotropic dichroic film obtained from a mixed colloidal solution, the absorption coefficient and the refractive index can take various values within the range determined by the initial composition. Due to a characteristic dimension of the organic compound used (intermolecular spacing 3.4±0.3 Å), it is possible to mix different colloidal systems in this way to form composite supramolecules. The thickness of the optically anisotropic dichroic crystal film is determined by the content of solid matter in the applied solution. During film formation, a technical parameter that is conveniently controlled under commercial production conditions is solution concentration. The crystallinity of the final wafer can be monitored by X-ray diffraction and/or optical methods. Additional treatments may be performed on the substrate to which the thin crystal film is applied to ensure uniform wetting of the surface and to provide hydrophilicity of the surface. Possible treatments include machining, annealing, and mechanochemical treatments, among others. Before applying the crystalline film, the surface of the substrate can be machined so as to form an anisotropic alignment structure, which can increase the degree of orientation of the molecules in the obtained crystalline film.

Polarizers can be processed to create a surface microscopic roughness that is characterized by a particular orientation so that the polarizer can perform the function of an alignment layer.

The desired anisotropy of the absorption coefficient and refractive index, as well as the orientation of the major axes can be guaranteed by establishing a specific angular distribution of molecules in the polarizing film on the substrate surface (i.e., the optical characteristic).

The optical properties of the crystal thin film can be controlled by the above methods during the manufacturing process, so the layer properties can be adjusted according to the needs of various special applications. For example, the absorption spectrum of polarizers can be tuned, which can improve the color rendering and achromaticity of displays. Birefringent films can be used as phase retarders by presetting the phase shift at specific wavelengths. The angular characteristics of liquid crystal displays with thin-film crystal polarizers can be improved by varying the optical anisotropy of the film.

The optical dichroism of the film allows the use of such polarizers as phase retarders to improve the contrast and/or angular characteristics of liquid crystal displays.

Another important feature of the Optiva TCF ^™ polarizer of the present invention is its small thickness. The performance of an LCD depends largely on the thickness of the layers in the design. One of the reasons why conventional polarizers, especially PVA-based polarizers, are not used as internal polarizers even if a protective layer is applied is that the thickness of the added protective layer is greater than 200 microns.

The Optiva TCF ^™ polarizers of the present invention are less than 1 micron thick and, if necessary, even with the addition of additional layers, are significantly thinner than conventional polarizers. For example iodine type.

The position of the polarizer relative to other layers in the display depends on the polarizer type. Prism-type polarizers are usually located on the front and outside of the liquid crystal display layer structure. Crystal thin film polarizers can be placed between other liquid crystal display layers.

Liquid crystal displays include other functional layers required for proper functioning of the display. Image control in liquid crystal displays is provided by electrode layers. The electrode layer material is required to have a relatively low electrical resistance and provide a connection for the control voltage supply. In addition, the electrodes are required to be transparent so that a sufficiently bright image can be obtained. In most cases, the electrodes are made of a transparent conductive material of the Indium Tin Oxide (ITO) type. In some liquid crystal displays (eg, single polarizer retroreflective types), one of the electrodes may be opaque.

The alignment layer (aligner) is used for the alignment of the liquid crystal molecules in the nematic phase. The alignment layer determines the twist angle of the liquid crystal and is usually directly connected to the liquid crystal. Typically, the alignment layer is made of a polymer material such as polyamide (eg SE3210 Nissan).

The substrate in liquid crystal displays protects the above-mentioned functional layers from external factors and serves as a mechanical base element. The substrate is usually made of, for example, glass or plastic, usually about 0.7mm thick, and has a refractive index of about 1.5.

The thickness and materials of the auxiliary layers are selected based on their functionality and transparency requirements in the wavelength range of 400nm to 700nm.

Liquid crystal displays may include other layers to improve image quality and electrical characteristics, and to prevent undesired physical and chemical interactions between adjacent layers, among other purposes.

For example, phase delay (phase compensation) or retardation layers can be used to improve image quality and color reproduction. According to the disclosed invention, the retardation layer may be located on one or both panels of the display. In some embodiments, the retarder layer is made of a heat-resistant material manufactured by Optiva Corporation, see Lazarev, P. et al., Abstracts of Technical Papers at the SID International Symposium, San Jose, CA, June 2001, Vol. 32, 571- "Submicron Thin Retardation Coating" published on page 573 (SID, Int.Symp.Digest of Technical Papers, San Jose, CA, June 2001, Vol.XXXII, pp.571-573) and T.Fiske et al., 2002 "Molecular Alignment in Crystal," May 2002, Abstracts of Technical Papers of the SID International Symposium, Boston, MA, pp. 866-869 (SID, Int. Symp. Digest of Technical Papers, Boston, Ma, May 2002, pp.866-869 Polarizers and Retarders". Optaiva TCF retarders are thin film layers inside the liquid crystal cell that can be used at various positions relative to other functional elements of the liquid crystal display. In some embodiments, a liquid crystal display with an internal polarizer may have a TCF retarder layer between the internal polarizer and electrodes on the same panel. However, in another embodiment, a liquid crystal display designed with an inner polarizer and an outer polarizer on one panel, the TCF retarder layer can be placed between the inner polarizer and the electrode or between the two polarizers.

Additional protective layers can be used to protect other layers from damage during manufacture and operation of the liquid crystal display. For example, it is desirable to protect the outer front polarizer by a special outer layer. An insulating layer (eg, SiO ₂ ) can increase the resistance between the electrodes and protect the liquid crystal display structure from electrical breakdown. The adhesive layer enables better mutual adhesion between the functional layer and the auxiliary layer. A planarization layer can be used to even out the roughness on the liquid crystal display element. Undesirable interference effects are suppressed, for example, by a diffusely reflective layer with a rough surface. Color filter substrates can be used for the formation of color images in color liquid crystal displays. A diffuse scattering layer can be used to increase the viewing angle and suppress unwanted interference. Anti-reflective coatings can be used to improve contrast, etc.

Various functions may be combined and performed by a single layer made of a particular material or formed by a particular method. For example, a liquid crystal display may include reflective polarizers, or reflective electrodes, or polarizer/alignment layers.

Some other functional layers may also be arranged between the electrodes and the substrate layer, as long as these layers do not hinder the normal function of the liquid crystal display and do not affect the obtained technical results.

For example, existing processes that use photolithography followed by etching to form electrode layers require the use of a protective acrylic layer to protect the polarizer from contact with the etching solution. An acrylic layer is deposited on the electrode-facing side of the polarizer. In addition to protecting the polarizer from etching during electrode formation, the acrylic layer also prevents polarizer components (eg, metal ions) from dissolving during LCD operation.

The other side of the polarizer can also be attached to an additional layer, for example, a planarization layer to homogenize the roughness of the diffuser mirror in reflective displays, or to protect the polarizer from specular reflection layers in reflective displays. Aluminum ion-diffusing layer.

The space between the electrodes and the liquid crystal layer can also accommodate additional polarizers, phase retarders, color filter substrates, and adhesive films, among others.

In another embodiment, the thickness and order of the functional layers are chosen to ensure that at least one wavelength in the interference extremum in the output of the display is within the spectral range of 500nm to 600nm. This is to ensure that the high brightness of the display is within the most sensitive range of the human eye.

The LCD of the disclosed invention may include a plurality of polarizers. Typically, a liquid crystal display structure includes two polarizing layers, one on each side of the liquid crystal layer. Each polarizer can be arranged according to the proposed functional order of the layers. At the same time, the quality of the polarizer can be improved by using a pair of polarizing layers with an intermediate adhesive on each side of the liquid crystal. This double polarizer can also be located between the electrode and the substrate on one side of the liquid crystal. Reducing the thickness of the polarizer can further improve the performance of the liquid crystal display. For example, a standard iodine polarizer used in most liquid crystal displays is approximately 100 microns thick. The thickness of the polarizer used in the liquid crystal display of the present invention is as small as 1 micron, or less than 1 micron. The polarizer is made of an optically anisotropic dichroic liquid crystal film. Polarizers made of TCF have extremely small thickness, low temperature sensitivity, highly anisotropic refractive index, good angular characteristics, high oblique polarization capability, and large dichroic ratio.

Another embodiment of the invention discloses a liquid crystal design with a high temperature resistant internal polarizer on one panel and an external polarizer on the other panel. In this case, two designs can be considered. One design has an internal polarizer in the rear panel, while the other has an internal polarizer in the front panel. In this embodiment, the outer polarizer can be the same high durability polarizer as used for the inner polarizer, or it can be any type of polarizer. The design of this embodiment can be used with any type of liquid crystal display, including reflective, transmissive, and transflective designs, and these designs will exhibit the above-mentioned advantages of the disclosed liquid crystal display.

Yet another embodiment of the present invention is a liquid crystal display further comprising a retardation layer. The retardation layer can also be made of high temperature resistant material.

Another embodiment of the present invention is a transflective liquid crystal display comprising three polarizers, two of which are external polarizers and one of which is an internal polarizer. In this embodiment, the one or two outer polarizers polarizers may be the same high durability polarizers used for the inner polarizers, or any type of polarizer. This design will demonstrate the above-mentioned advantages of the disclosed liquid crystal display.

The present invention will be described below with reference to the accompanying drawings.

Figure 1 (prior art) shows a liquid crystal display with two external polarizers. The liquid crystal display includes two protective layers 101 for protecting two outer polarizers 102 from scratches and moisture etc. from both sides of the display. Polarizers 102 are placed on corresponding transparent substrates 103 . The liquid crystal display includes two electrodes 104 , two alignment layers 105 , and a liquid crystal layer 106 . Except for the protective layer 101, the liquid crystal display shown in FIG. 1 is characterized by a large thickness and an increased optical distance. These factors lead to a decrease in corner characteristics.

FIG. 2 (Prior Art) shows a liquid crystal display with two internal polarizers, both of which are located between the plurality of electrodes 104 . The first inner polarizer 201 is placed between the electrode 104 and the liquid crystal layer 106 in the front panel, and functions as an alignment layer for the liquid crystal layer 106 . The second polarizer 202 is placed between the alignment layer 105 and the electrode 104 in the rear panel. This design does not require combining the alignment layer 105 and the second polarizer 202 into a single layer. Due to the placement of the polarizer layers 201 and 202 between the plurality of electrodes 104, this design requires a high operating voltage and may have a low multiplication factor, among other things. These disadvantages are related to the relatively high dielectric constant of the polarizer material. Another disadvantage of the LCD shown in FIG. 2 is the direct contact between the first polarizer/alignment layer 201 and the liquid crystal layer 106 . This can lead to intermixing of the layers by solid state diffusion, which can poison the polarizer 201 and/or the liquid crystal layer 106 .

FIG. 3 illustrates a liquid crystal display according to one embodiment of the disclosed invention. Two internal polarizers 301 are located between the electrodes 104 and the transparent substrate 103 in the front panel and in the rear panel, respectively. A liquid crystal layer 106 and two alignment layers 105 on both sides of the liquid crystal layer 106 are accommodated between the plurality of electrodes 104 . The use of the internal polarizer 301 in the LCD shown in Figure 3 increases the viewing angle, improves the angular characteristics, reduces the thickness of the display, simplifies the design of the display screen, and significantly strengthens the protection of the polarizer layer from scratches and moisture. Protect. In addition, disposing the internal polarizer 301 outside the electrode 104 reduces the operating voltage and increases the multiplexing rate of the display. Additionally, the placement of electrodes 104 between the inner polarizer layer 301 and the liquid crystal layer 106 in each panel provides protection of the liquid crystal layer and polarizer layer from diffusion poisoning. According to another embodiment of the invention not shown in this figure, the transmissive LCD can have a different design with an internal polarizer on only one of the two panels and an external polarizer on the other panel, between its multiple functional layers.

FIG. 4 illustrates a reflective LCD including a reflective layer 401 according to one embodiment of the disclosed invention. The reflective layer 401 enables the LCD to form an image using light from an ambient light source or a front light source. Reflective LCDs also significantly reduce power consumption. According to another embodiment of the invention not shown in this figure, the reflective LCD has another design with an internal polarizer in only one of the two panels and an external polarizer in the other panel, between its multiple functional layers.

Figure 5 illustrates a transflective LCD according to one embodiment of the disclosed invention. The LCD includes a translucent reflective layer 401 . The backlight system 501 is located on the rear side of the liquid crystal display. The transflective layer and backlight system provide a transflective type LCD. The transflective LCD combines the advantages of reflective and transmissive LCDs. In addition to backlighting, transflective LCDs can also use ambient or front lighting.

According to another embodiment of the present invention, the transflective LCD can have many different designs. According to one of them, only one of the two panels has an internal polarizer, while the other panel has an external polarizer, between its functional layers. In another embodiment, at least three polarizers are included, two of which are external polarizers and one is an internal polarizer. In this embodiment, the one or two outer polarizers may be the same high durability polarizers used for the inner polarizers, or any type of polarizer. In another embodiment not specifically described in this specification, however, the internal polarizer does not cover the entire substrate surface, in other words its surface area on the optical path is smaller than the area covered by the liquid crystal material.

FIG. 6 shows a liquid crystal display according to one embodiment of the disclosed invention, the liquid crystal display comprising a reflective layer 601 which simultaneously performs the function of an electrode. The electrode/reflective layer 601 is disposed on the rear side of the display, between the transparent substrate 103 and the alignment layer 105 . The advantage of the LCD shown in Figure 6 is the use of ambient light sources and the small overall thickness of the layers of the display. The small total thickness of these layers provides high angle characteristics and high brightness of the liquid crystal display.

Figure 7 illustrates a transmissive LCD according to one embodiment of the disclosed invention. A transmissive LCD includes a backlight system 501 disposed behind the liquid crystal display. The backlight system makes the disclosed liquid crystal display self-illuminating without the need for ambient light.

The LCD provided by the invention greatly reduces the working voltage and capacitance of the LCD, increases the image brightness and contrast of the liquid crystal display, the viewing angle, and the robustness against surface mechanical damage. The disclosed invention does not complicate the manufacturing process of liquid crystal displays. In addition, the LCD of the present invention reduces the loss of light flux in the structure of the liquid crystal display and reduces the thickness of the display.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (23)

1. A liquid crystal display, comprising: front panel; rear panel; and a liquid crystal layer, located between the two panels, wherein an internal polarizer is included in at least one of the front panel and the rear panel, the internal polarizer being located between an electrode in the panel and a substrate; and The internal polarizer is made of a material that is chemically stable at high temperatures of at least 150°C. 2. The liquid crystal display according to claim 1, wherein the internal polarizer is made of an optically anisotropic dichroic film comprising rod-shaped supramolecules, the The rod-shaped supramolecule includes at least one disc-shaped polycyclic organic compound having a conjugated π system, and the film is characterized in that the spacing between molecules is 3.4 ± 0.3 Å along its polarization axis. 3. The liquid crystal display of claim 2, wherein the optically anisotropic dichroic film is formed of a lyotropic liquid crystal comprising at least one dichroic dye. 4. The liquid crystal display according to any one of claims 1 to 3, wherein the thickness of the inner polarizer is less than 1 micron. 5. The liquid crystal display according to any one of claims 1 to 4, wherein the polarizer material is chemically stable at a high temperature of at least 200°C. 6. The liquid crystal display according to any one of claims 1 to 5, comprising, in addition to the internal polarizer, an external polarizer on the panel. 7. The liquid crystal display according to any one of claims 1 to 6, wherein the rear panel further comprises a reflective layer. 8. The liquid crystal display according to any one of claims 1 to 6, wherein the rear panel further comprises a translucent reflective layer and a backlight system. 9. The liquid crystal display according to any one of claims 7 or 8, wherein the front panel further comprises a front light system. 10. A liquid crystal display according to any one of claims 7 to 9, wherein the reflective layer is diffuse. 11. A liquid crystal display according to any one of claims 7 to 9, wherein the reflective layer is specular. 12. A liquid crystal display according to any one of claims 7 to 11, wherein the reflective layer is electrically conductive and performs the function of an electrode. 13. A liquid crystal display according to any one of claims 8 to 14, further comprising at least one external polarizer. 14. The liquid crystal display of claim 13, wherein the external polarizer is located in the same panel as the internal polarizer. 15. The liquid crystal display according to any one of claims 1 to 14, wherein the inner polarizer partially covers the substrate. 16. A liquid crystal display according to any one of claims 1 to 15, wherein the rear panel comprises a backlight system. 17. A liquid crystal display according to any one of claims 1 to 16, wherein the polarizer performs the function of a phase retarder and/or a correction filter. 18. A liquid crystal display according to any one of claims 1 to 17, further comprising an anti-reflection or anti-glare coating on a front surface of the display. 19. The liquid crystal display according to any one of claims 1 to 18, further comprising a layer selected from the group consisting of a retardation layer, a protective layer, a light scattering layer, a polarizing layer, a correction filter layer, and an insulating layer. at least one functional layer. 20. The liquid crystal display according to any one of claims 1 to 19, further comprising a retardation layer made of an optically anisotropic dichroic film, the optically anisotropic dichroic The film comprises a rod-shaped supramolecule comprising at least one disc-shaped polycyclic organic compound having a conjugated π system, and the film is characterized in that the intermolecular spacing along its polarization axis is 3.4 ± 0.3 . 21. A liquid crystal display according to any one of claims 1 to 20, wherein the thickness and the order of the functional layers are selected to ensure that at least one wavelength of the interference extremum in the output of the display is within the spectral range of 500nm to 600nm . 22. A liquid crystal display according to any one of claims 6 or 13, wherein said external polarizer is made of an optically anisotropic dichroic film comprising A rod-shaped supramolecule comprising at least one disc-shaped polycyclic organic compound having a conjugated π system, and the film is characterized in that the spacing between molecules is 3.4 ± 0.3 Å along its polarization axis. 23. The liquid crystal display of claim 22, wherein the optically anisotropic dichroic film is formed of a lyotropic liquid crystal comprising at least one dichroic dye.

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