MXPA98006884A - An opt movie - Google Patents

Abstract

The invention relates to an optical film, which comprises a dispersed phase of polymer particles placed within a continuous birefringent matrix. The film is oriented, typically by stretching, in one or more directions. The size and shape of the particles of the dispersed phase, the volume fraction of the dispersed phase, the thickness of the film, and the amount of orientation are chosen to achieve a desired degree of diffuse reflection and total transmission of electromagnetic radiation of a length desired wavelength in the film result

Description

AN OPTICAL FILM Field of the Invention This invention relates to optical materials which contain structures suitable for controlling the optical characteristics, such as reflectance and transmission. In a further aspect, it relates to the control of specific polarizations of reflected and transmitted light.

Background of the Invention Optical films are known for the art, which are constructed of scattered inclusions within a continuous matrix. The characteristics of these inclusions can be manipulated to provide a range of reflective and transmissible properties to the film. These characteristics include the inclusion size with respect to the wavelength within the film, the shape and alignment of inclusion, the volumetric fill factor of inclusion and the degree of inequality of the refractive index with the continuous matrix along the the three orthogonal axes of the film.

Conventional absorbent polarizers (dichroic) have, as their inclusion phase, similar inorganic chains Ref. 028114 to a light absorbing iodine rod, which is aligned within a polymer matrix. Such a film will tend to absorb the polarized light with its electric field vector aligned parallel to the iodine chains similar to a rod, and transmit the polarized light perpendicular to the rods. Because iodine chains have two or more dimensions "that are small compared to the wavelength of visible light, and because the number of chains per cubic wavelength of light is large, the optical properties of such a film is predominantly specular, with very little diffuse transmission through the film or diffuse reflection of the film surfaces.Also most other commercially available polarizers, these polarizing films are based on selective polarization absorption.

Films filled with inorganic inclusions with different characteristics can provide other optical and reflective transmission properties. For example, pieces of mica coated with two or more dimensions that are large compared to visible wavelengths have been incorporated into polymeric films and paints to impart a metallic sheen. These pieces can be manipulated to be in the plane of the film, therefore a strong directional dependence is imparted to the reflective appearance. Such an effect can be used to produce security screens that are highly reflective for certain angles of view, transmissible to other angles of view. Large pieces that have a coloration (selective reflection in a specular manner) that depends on the alignment with respect to the incident light, can be incorporated into a film to provide evidence of alteration. In this application, it is necessary that the pieces in the film similarly align with respect to each other.

However, optical films made from polymers filled with inorganic inclusions suffer from a variety of frailties: Typically, adhesion between the inorganic particles and the polymer matrix is poor. Accordingly, the optical properties of the film decrease when the intense stress or strain is applied across the matrix, both because the union between the matrix and the inclusions is arranged, and because the rigid inorganic inclusions can be fractured. . In addition, the alignment of inorganic inclusions requires process steps and considerations that complicate manufacturing.

Other films, such as those described in U.S. 4,688,900 (Doane et al.), Consist of a continuous light-transmitting polymer matrix of light, with droplets of liquid light-modulating crystals dispersed therein. The elongation of the material is said to result in the distortion of the liquid crystal droplet from a spherical to an ellipsoidal shape, with the long axis of the ellipsoid parallel to the direction of elongation. The U.S. 5,301,041 (Konuma et al.) Makes a similar description, but achieves the distortion of the liquid crystal droplet through the application of pressure. A. Aphonin, "Optical Properties of Stretched Polymer Dispersed Liquid Crystal Films: Angle-Dependent Polarized Light Scattering, Liquid Crystals, Vol. 19, No. 4,469-480 (1995), discusses the optical properties of stretched films consisting of droplets of liquid crystals placed inside a polymer matrix It is reported that the elongation of the droplets in an ellipsoidal shape, with their long axes parallel to the direction of stretching, imparts a birefringence oriented (difference of the index refriicción between the dimensional axes of the droplet) to the droplets, resulting in an inequality of the relative refractive index between the scattered and continuous phases along certain axes, and an equality of the relative index along other film axes. they are not small in comparison to the wavelengths visible in the film, and therefore the optical properties of such films have a Substantial diffuse component for its reflective and transmissible properties. Aphonin suggests the use of these materials as a polarizing disjector for backlit braided pneumatic LCDs. However, optical films that employ liquid crystals as the substantially dispersed phase are limited in the degree of equality of the refractive index between the matrix phase and the dispersed phase. In addition, the birefringence of the liquid crystal component of such films is typically temperature sensitive.

The U.S. 5,268,225 (Isayev) discloses a laminated composite made from thermotropic liquid crystal polymer blends. The mixture consists of two liquid crystal polymers which are immiscible with each other. The mixtures can be melted into a film consisting of a disperse inclusion phase and a continuous phase. When the film is stretched, the dispersed phase forms a series of fibers whose axes align in the direction of stretching. While the film is described based on the improved mechanical properties, no allusion is made to the optical properties of the film. However, due to their liquid crystal nature, films of this type suffer from the frailties of other liquid crystal materials discussed above.

Still other films have been made to exhibit the desirable optical properties by means of the application of electric or magnetic fields. For example, U.S. 5,008,807 (Waters et al.) Discloses a liquid crystal device, which consists of a layer of fibers impregnated with a liquid crystal material and placed between two electrodes. A voltage across the electrodes produces an electric field which changes the birefringent properties of the liquid crystal material, resulting in several degrees of inequality between the refractive indices of the fibers and the liquid crystal. However, the requirement of an electric or magnetic field is inconvenient and undesirable in many applications, particularly where there are fields that can cause interference.

Other optical films have been made by incorporating a dispersion of inclusions of a first polymer into a second polymer, and then stretching the resulting compound in one or two directions. The U.S. 4,871,784 (Otonari et al.) Is an example of this technology. The polymers are selected so that there is low adhesion between the dispersed phase and the surrounding matrix polymer, so that an elliptical void space is formed around each inclusion when the film is stretched. Such empty spaces have dimensions of the order of visible wavelengths. The inequality of the refractive index between the void space and the polymer in these "microvaccinated" films is typically very large (approximately 0.5), causing substantial diffuse reflection. However, the optical properties of microvanced materials are difficult to control due to variations in the geometry of the interfaces, and it is not possible to produce an axis of the film by which refractive indexes are relatively equal, as it should be useful for optical properties sensitive to polarization. In addition, empty spaces of such material can easily collapse through exposure to heat and pressure.

Optical films have also been produced, where a dispersed phase is deterministically arranged in an ordered pattern within a continuous matrix. The U.S. 5,217,794 (Schrenk) is an example of this technology. There, a laminar polymer film is described, which is made of polymeric inclusions which are large in comparison with the wavelength in the two axes, placed inside a continuous matrix of another polymeric material. The refractive index of the dispersed phase differs significantly from that of the continuous phase along one or more of the laminated axes, and is relatively appropriately equated along another. Due to the ordering of the dispersed phase, films of this type exhibit strong iridescence (ie, interference-dependent colouration based on interference) for examples in which they are substantially reflective. As a result, the use of such films has been limited for optical applications where optical diffusion is desirable.

Therefore there remains a need in the art for an optical material consisting of a continuous and a dispersed phase, where the refractive index inequality between the two phases along the three dimensional axes of the material can conveniently and permanently be manipulated to achieve the desired degrees of reflection and diffuse and specular transmission, where the material optical is stable with respect to intense stress, voltage, temperature differences, and electric and magnetic fields, and where the optical material has an insignificant level of iridescence. These and other needs are met by the present invention, as described below.

Brief description of the Drawings FIG. 1 is a schematic drawing illustrating an optical body made in accordance with the present invention, wherein the dispersed phase is arranged as a series of elongated masses having essentially a circular cross-section; FIG. 2 is a schematic drawing illustrating an optical body made in accordance with the present invention, wherein the dispersed phase is arranged as a series of elongated masses having essentially an elliptical cross section; FIG.3a-e are schematic drawings illustrating various forms of the dispersed phase in an optical body made in accordance with the present invention; FIG. 4a is a graph of the bidirectional dispersion distribution as a function of the scattered angle for a oriented film according to the present invention for polarized light perpendicular to the direction of orientation; FIG. 4b is a graph of the bidirectional dispersion distribution as a scatter angle function for a film oriented in accordance with the present invention for polarized light parallel to the direction of orientation; Y FIG. 5 is a schematic representation of a multilayer film made in accordance with the present invention.

Brief Description of the Invention In another aspect, the present invention relates to a diffusively reflective film or other optical body comprising a continuous birefringent polymer phase and a non-birefringent dispersed phase substantially placed within the continuous phase. The refractive indices of the continuous and substantially dispersed phases are substantially unequal (ie, they differ from each other by greater than about 0.05) along a first axis of the three orthogonal axes reciprocally, and substantially equalize ( that is, they differ by less than about 0.05) along a second axis of the three orthogonal axes reciprocally. In some embodiments, the refractive indices of the substantially continuous and dispersed phases may be matched or unequal along, or parallel to, a third axis of the three orthogonal axes reciprocally to produce a mirror or a polarizer. Incident light polarized along, or parallel to, an unequal axis is scattered, resulting in a significant diffuse reflection. Incident light polarized along an even axis is dispersed to a much lesser degree and is significantly transmitted specularly. These properties can be used to manufacture optical films for a variety of uses, including reflective (significantly non-absorbent) low loss polarizers so that light polarizations that are not significantly transmitted are diffusedly reflected.

In a referred aspect, the present invention relates to an optical film or other optical body comprising a continuous birefringent phase and a dispersed phase, wherein the refractive indices of the continuous and dispersed phases substantially equalize (i.e., where the difference of the index between the continuous and dispersed phases is less than 0.05) along an axis perpendicular to a surface of the optical body.

In another aspect, the present invention relates to a composite optical body comprising a first continuous birefringent polymeric phase, in which the second phase can be birefringent, but in which the degree of equality and inequality in at least two orthogonal directions is mainly due to the birefringence of the first phase.

In a still further aspect, the present invention relates to a method for obtaining a diffuse reflective polarizer, comprising the steps of: providing a first resin, whose degree of birefringence can be altered by the application of a force field, such as by the dimensional orientation or an applied electric field, so that the resulting resin material has, for at least two orthogonal directions, a refractive difference index of greater than about 0.05; providing a second resin, dispersed within the first resin; and applying the force field to the composite of both resins so that the indexes of the two resins are approximately equalized to less than about 0.05 in one of the two directions, and the difference in the index between the first and second resin in the another of the two directions is greater than about 0.05. In a referred embodiment, the second resin is dispersed in the first resin after the imposition of the force field and the subsequent alteration of the birefringence of the first resin.

In still another aspect, the present invention relates to an optical body that acts as a reflective polarizer with a high extinction rate. In this regard, the difference of the index in the equality direction is chosen as small as possible and the difference in the direction of inequality is maximized. The fraction volume, thickness, and particle size and shape of the dispersed phase can be chosen to maximize the extinction ratio, although the relative importance of the transmission and optical reflection for the different polarizations can vary for different applications.

In another aspect, the present invention relates to an optical body comprising a continuous phase, a dispersed phase whose refractive index differs from the continuous phase by greater than about 0.05 along a first axis and by less than about 0.05 at along a second axis orthogonal to the first axis, and a dichroic dye. The optical body is preferably oriented along at least one axis. The dichroic dye improves the extinction coefficient of the optical body by absorbing, in addition to the dispersion, the polarized light parallel to the axis of the orientation.

In various aspects of the present invention, the reflection and transmission properties of at least two orthogonal polarizations of incident light are determined by the selection or manipulation of various parameters, including the optical indices of the continuous and dispersed phases, the size and shape of the the particles of the dispersed phase, the volume fraction of the dispersed phase, the thickness of the optical body through which the incident light is passed, and the wavelength or wavelength band of electromagnetic radiation of interest.

The magnitude of the equality or inequality of the index along a particular axis will directly affect the degree of dispersion of the polarized light along that axis. In general, scattering dust varies by the square of the index inequality. Therefore, the greatest inequality of the index along a particular axis, the strongest dispersion of polarized light along that axis. Conversely, when the inequality along a particular axis is small, the polarized light along that axis is dispersed to a smaller extent and is therefore transmitted in a specular manner through the volume of the body.

The size of the dispersed phase can also have a significant effect on the dispersion. If the particles of the scattered phase are too small (ie, less than about 1/30, the wavelength of light in the medium of interest) and if there are many particles per cubic wavelength, the optical body behaves as medium with a refractive index effective in some way between the indices of the two phases along any given axis. In such a case, very little light is scattered. If the particles are too large, the light in a specular way is reflected from the surface of the particle, with very little diffusion in other directions. When the particles are too large in at least two orthogonal directions, undesirable iridescence effects may also occur. Practical limits can also be reached when the particles become large, so that the thickness of the optical body becomes larger and the desired mechanical properties are arranged.

The shape of the particles of the dispersed phase can also have an effect on light scattering. The depolarization factors of the particles for the electric field in the refractive index of the equality and inequality directions can reduce or increase the amount of dispersion in a given direction. The effect can either be added or decreased from the amount of dispersion of the index inequality, but generally has a small influence on the dispersion in the preferred range of properties in the present invention.

The shape of the particles can also influence the degree of diffusion of scattered light from the particles. This shape effect is usually small, but it increases as it increases the dimensional proportion of the geometric cross section of the particle in the plane perpendicular to the direction of incidence of the light and since the particles are obtained relatively large. In general, in the operation of this invention, the particles of the dispersed phase should be smaller in size than several wavelengths of light in one or two orthogonal dimensions reciprocally if the diffuse reflection is preferred, rather than the specular one.

The dimensional alignment is also found to have an effect on the scattering behavior of the dispersed phase. In particular, it has been observed, in the optical bodies manufactured according to the present invention, that the aligned dispersers will not scatter the light symmetrically near the directions of transmission or specular reflection since the dispersers are randomly aligned. In particular, inclusions that have been elongated by orientation resembling rods scatter light mainly along (or near) a cone centered in the direction of orientation and having an edge along the transmitted direction of Specular way. For example, for the incident light of such an elongated rod in a direction perpendicular to the orientation, the scattered light appears as a band of light in the plane perpendicular to the direction of orientation with an intensity that decreases with a rising angle outside the directions specular Due to the adaptation of the geometry of the inclusions, some control over the distribution of scattered light can be achieved, both in the transmissible hemisphere and in the reflective hemisphere.

The volume fraction of the dispersed phase also affects the scattering of light in the optical bodies of the present invention. Within certain limits, increasing the volume fraction of the dispersed phase tends to increase the amount of scattering that a ray of light experiences after it enters the body for both directions of equality and inequality of polarized light. This factor is important to control the reflection and transmission properties for a given application. However, if the volume fraction of the dispersed phase becomes too large, the scattering light decreases. Without wishing to be bound by theory, this seems to be due to the fact that the particles of the dispersed phase are more closed together, in terms of the wavelength of the light, so that the particles tend to act together for a number smaller than large effective particles.

The thickness of the optical body is also an important control parameter, which can be manipulated to affect the reflection and transmission properties in the present invention. As the thickness of the optical body increases, diffuse reflection also increases, and transmission decreases, both specular and diffuse.

While the present invention will often be described here with reference to the visible region of the spectrum, various embodiments of the present invention can be used to operate at different wavelengths (and therefore frequencies) of electromagnetic radiation through an appropriate setting of the components of the optical body. Therefore, as the wavelength increases, the linear size of the components of the optical body increases so that the dimensions, measured in units of wavelength, remain approximately constant. Another major effect of changing the wavelength is, for most of the materials of interest, the refractive index and the change in the absorption coefficient. However, still the principles of equality and inequality of the index apply to each wavelength of interest.

Detailed description of the invention Introduction As used herein, the terms "Specular reflection" and "Specular reflectance" refer to the reflectance of light rays in a projecting cone with a corner angle of 16 degrees centered around the specular angle. The terms "Diffuse reflection" or "Diffuse reflectance" refer to the reflection of rays that are outside the specular cone defined above. The terms "Total Reflectance" or "Total Reflection" refer to the combined reflectance of all the light of a surface. Therefore, total reflection is the sum of the specular and diffuse reflection.

Similarly, the terms "Specular Transmission" and "Specular Transmittance" are used here with reference to the transmission of rays in a projecting cone with a corner angle of 16 degrees centered around the specular direction. The terms "diffuse transmission" and "diffuse transmittance" are used herein with reference to the transmission of all rays that are outside the specular cone defined above. The terms "Total Transmission" or "Total Transmittance" refers to the combined transmission of all light through an optical body. Thus, the total transmission is the sum of the specular and diffuse transmission.

As used, the term "extinction ratio" defined means the proportion of the total light transmitted in a polarization to the light transmitted in an orthogonal polarization.

FIGS. 1-2 illustrates a first embodiment of the present invention. According to the invention, a diffuse reflective optical film 10 or other optical body is produced, which consists of a birefringent matrix or continuous phase 12 and a continuous or dispersed phase 14. The birefringence of the continuous phase is typically at least about 0.05, preferably at least about 0.1, more preferably at least about 0.15, and most preferably at least about 0.2.

The refractive indices of the continuous and substantially dispersed phases are equalized (i.e., they differ by less than about 0.05) along a first axis of the three orthogonal axes reciprocally, and are substantially unequal (i.e. they differ by greater than approximately 0.05) along a second axis of the three orthogonal axes reciprocally. Preferably, the refractive indices of the continuous and dispersed phases differ by less than about 0.03 in the equality direction, more preferably, less than about 0.02 and more preferably, less than about 0.01. The refractive indices of the continuous and dispersed phases preferably differ in the direction of inequality by at least about 0.07, preferably by at least about 0.1, and more preferably, by at least about 0.2.

Inequality in refractive indices along a particular e ect has the effect that incident light polarized along that axis will substantially be dispersed, resulting in a significant amount of reflection. In contrast, the polarized incident light along an axis, in which the refractive indices are equalized, will be transmitted in a specular manner transmitted or reflected with a much lower degree of dispersion. This effect can be used to manufacture a variety of optical devices, including polarizers and reflective mirrors.

The present invention provides a practical and simple optical body and method for manufacturing a reflective polarizer, and also provides a means of obtaining a continuous range of optical properties according to the principles described herein. Also, very efficient low loss polarizers can be obtained with high extinction ratios. Other advantages are a wide range of practical materials for the dispersed phase and the continuous phase, and a high degree of control in obtaining optical bodies of high quality, predictable and consistent performance.

Effects of Equality / Inequality of the index In the preferred embodiment, the materials of at least one of the continuous and dispersed phases are of a type that undergoes a change in the refractive index with the orientation. Therefore, since the film is oriented in one or more directions, the inequalities or equalities of the refractive index occur along one or more axes. Due to the careful manipulation of the orientation parameters and other process conditions, the positive or negative birefringence of the matrix can be used to induce diffuse reflection or transmission of one or both light polarizations along a given axis. The relative proportion between transmission and diffuse reflection is dependent on the concentration of the inclusions of the dispersed phase, the thickness of the film, the square of the difference in the refractive index between the continuous and dispersed phases, the size and geometry of the the inclusions of the dispersed phase, and the wavelength or wavelength band of the incident radiation.

The magnitude of the equality or inequality of the index along a particular axis directly affects the degree of dispersion of polarized light along that axis. In general, the dispersion powder varies by the square of the index inequality. Therefore, the greatest inequality of the index along a particular axis, the strongest dispersion of polarized light along that axis. Conversely, when the inequality along a particular axis is small, the polarized light along that axis is dispersed to a lesser extent and is therefore transmitted in a specular manner through the volume of the body.

FIGS. 4a-b show this effect in oriented films manufactured in accordance with the present invention. There, a measurement of the typical Bidirectional Dispersion Distribution Function (BSDF) is shown for normal incident light at 632.8 nm. BSDF is described in J. Stover, "Optical Scattering Measurement and Analysis" (1990). The BSDF is shown as a function of the scattered angle for the light polarizations, both perpendicular and parallel to the axis of orientation. A scattered angle of zero corresponds to light (specularly transmitted) not scattered. For polarized light in the direction of equality of the index (ie, perpendicular to the direction of orientation) as in FIG. 4a, there is a maximum transmitted in a significant specular manner with a considerable component of diffusely transmitted light. (angle of dispersion between 8 and 80 degrees), and a small component of diffuse reflected light (scattering angle greater than 100 degrees). For polarized light in the direction of index inequality (ie, parallel to the direction of orientation) as in FIG. 4b, there is a light transmitted in a negligible specular manner and a greatly reduced component of diffusely transmitted light, and a considerably diffuse reflected component. It should be noted that the scattering plane shown by these graphs is the plane perpendicular to the direction of orientation where most of the scattered light exists for these elongated inclusions. The contributions of scattered light outside this plane are greatly reduced.

If the refractive index of the inclusions (ie, the dispersed phase) equals that of the continuous host medium along some axis, then the incident light polarized with the electric fields parallel to this axis will pass through the non-phase. dispersed with respect to the size, shape and density of the inclusions. If the indexes do not equal along an axis, then the inclusions will scatter the polarized light along this axis. For dispersers of a given cross-sectional area with dimensions greater than approximately? / 30 (where? Is the wavelength of light in the middle), the force of the dispersion is largely determined by the inequality of the index. The exact size, shape and alignment of an unequal inclusion plays a role in determining how much light will be scattered in various directions of that inclusion. If the density and thickness of the dispersion layer is sufficient, according to the theory of multiple dispersion, the incident light will be either reflected or absorbed, but not transmitted, without considering the details of the size and shape of the disperser.

When the material is used as a polarizer, it is preferably processed, by stretching and leaving some dimensional relaxation in the transverse stretch plane direction, so that the difference in the refractive index between the continuous and dispersed phases is greater throughout of a first axis in a plane parallel to a surface of the material and is small along two other orthogonal axes. This results in a large optical anisotropy for electromagnetic radiation of different polarizations.

Some of the polarizers within the scope of the present invention are elliptical polarizers. In general, the elliptical polarizers will have a difference in the refractive index between the dispersed phase and the continuous phase for both directions of stretching and transverse. The proportion of the forward to backward dispersion is dependent on the difference in the refractive index between the continuous and dispersed phases, the concentration of the dispersed phase, the size and shape of the dispersed phase, and the overall thickness of the film. In general, elliptical diffusers have a relatively small difference in the refractive index between the particles of the dispersed and continuous phases. Due to the use of a diffuser based on birefringent polymer, a sensitivity to elliptical polarization (ie, diffuse reflectivity depending on the polarization of light) can be highly achieved. At one end, where the refractive index of the polymers are equalized on one axis, the elliptical polarizer will be a diffuse re-flexing polarizer.

Methods of Obtaining Equality / Inequality of the Index The materials selected for use in a polarizer according to the present invention, and the degree of orientation of these materials, are preferably chosen so that the phases in the finished polarizer have at least one axis for which the associated refractive indexes of Substantial way are the same. The equality of the refractive indices associated with that axis, which typically, but not necessarily, is an axis transverse to the direction of orientation, result in substantially no reflection of light in that plane of polarization .

The dispersed phase may also exhibit a decrease in the refractive index associated with the direction of orientation after stretching. If the birefringence of the host is positive, a birefringence induced by the negative tension of the dispersed phase has the advantage of increasing the difference between the refractive indices of the adjacent phases associated with the axis of orientation while the reflection of light with its plane polarization perpendicular to the direction of orientation is still negligible. The differences between the refractive indices of the adjacent phases in the direction orthogonal to the direction of orientation should be less than about 0.05 after orientation, and preferably, less than about 0.02.

The dispersed phase may also exhibit a birefringence induced by positive tension. However, this can be altered by means of the heat treatment until the refractive index of the axis perpendicular to the orientation direction of the continuous phase is equalized. The temperature of the heat treatment should not be high to relax the birefringence in the continuous phase.

Size of the Dispersed Phase The size of the dispersed phase can also have a significant effect on the dispersion. If the particles of the dispersed phase are too small (ie less than about 1/30 the wavelength of light in the medium of interest) and if there are many particles per cubic wavelength, the optical body behaves as a medium with an index of refraction effective in a certain way between the indices of the two phases along any of the given axes. In such a case, very little light is scattered. If the particles are too large, the light in a specular way is reflected from the surface of the particle, with very little diffusion in other directions.

When the particles are too large in at least two orthogonal directions, unwanted iridescence effects may also occur. Practical limits can also be reached when the particles become large, so that the thickness of the optical body becomes larger and the desired mechanical properties are arranged.

The dimensions of the particles of the dispersed phase after alignment may vary depending on the desired use of the optical material. Therefore, for example, the dimensions of the particles may vary depending on the wavelength of the electromagnetic radiation that is of interest in a particular application, with different dimensions required to reflect or transmit the visible, ultraviolet, infrared and radiation. microwave. Generally, however, the length of the particles must be such that they are approximately greater than the wavelength of electromagnetic radiation of interest in the medium, divided by 30.

Preferably, in applications where the optical body is used as a low loss reflective polarizer, the particles will have a length that is greater than about 2 times the wavelength of the electromagnetic radiation over the wavelength range of interest , and preferably by 4 times the wavelength. The average diameter of the particles is preferably equal to or less than the wavelength of the electromagnetic radiation over the wavelength range of interest, and preferably less than 0.5 of the desired wavelength. While the dimensions of the dispersed phase are a secondary consideration in most applications, it becomes more important in thin-film applications, where in a comparative manner there is little diffuse reflection.

Geometry of the Dispersed Phase While index inequality is the predominant factor that depends on promoting dispersion in the films of the present invention (i.e., a diffuse mirror or polarizer manufactured in accordance with the present invention has a substantial inequality in the refractive indexes of the continuous and scattered phases along at least one axis), the geometry of the particles of the dispersed phase may have a secondary effect on the dispersion. Therefore, the depolarization factors of the particles for the electric field in the directions of equality and inequality of the refractive index can reduce or increase the amount of dispersion in a given direction. For example, when the dispersed phase is elliptical in a cross section taken along a plane perpendicular to the axis of orientation, the elliptical cross-sectional shape of the dispersed phase contributes to the asymmetric diffusion in both the scattered light backward and the scattered light forward. The effect may either add or decrease the amount of dispersion of the index inequality, but generally have a small influence on the dispersion in the preferred range of properties in the present invention.

The shape of the particles of the dispersed phase can also influence the degree of diffusion of scattered light from the particles. This shape effect is generally small, but it increases by the dimensional proportion of the geometric cross section of the particle in the plane perpendicular to the direction of incidence of the light increments and by the relatively large particles obtained. In general, in the operation of this invention, the particles of the dispersed phase must be of smaller size than several wavelengths of light in one or two orthogonal dimensions reciprocally if the diffuse reflection is preferred, rather than the specular one.

Preferably, for a low loss reflective polarizer, the preferred embodiment consists of a dispersed phase placed within the continuous phase as a series of rod-like structures which, as a consequence of the orientation, have a high dimensional proportion which can increase the reflection for polarizations parallel to the direction of orientation by increasing the dispersion force and the dispersion for that polarization in relation to the polarizations perpendicular to the direction of orientation. However, as indicated in FIGS 3a-e, the dispersed phase can be provided with many different geometries. Therefore, the dispersed phase can be disk-shaped or elongated disk-shaped, as in FIGS. 3. a-c, rod-shaped, as in FIG.3d-e, or spherical. Other embodiments are contemplated, wherein the dispersed phase has cross sections, which are approximately elliptical (including circular), polygonal, irregular or a combination of one or more of these forms. The shape and size of the cross section of the particles of the dispersed phase can also vary from one particle to another, or from one region of the film to another (i.e., from the surface to the core).

In some embodiments, the dispersed phase may have a core or shell construction, wherein the core or shell is made out of the same or different materials, or where the core is hollow. Thus, for example, the dispersed phase may consist of hollow fibers of equal or random lengths, and of a uniform or non-uniform cross section. The interior space of the fibers can be emptied, or can be occupied by a suitable medium which can be a solid, liquid, or gas, and can be organic or inorganic. The refractive index of the medium can be chosen in consideration of the refractive indices of the dispersed phase and the continuous phase to achieve a desired optical effect (ie, reflection or polarization along a given axis).

The geometry of the dispersed phase can be achieved by means of suitable orientation or processing of the optical material, although the use of the particles having a particular geometry, or by means of a combination of the two. Therefore, for example, a dispersed phase having a rod-like structure can substantially be produced by orienting a film consisting of approximately spherical dispersed phase particles along a single axis. The rod-like structures can be given with an elliptical cross section orienting the film in a second direction perpendicular to the first. As a further example, a dispersed phase having a rod-like structure in which the rods are rectangular in cross-section can be produced by orienting in a single direction a film having a dispersed phase consisting essentially of a series of pieces rectangular Dispersion is a convenient way to achieve in a desired geometry, since dispersion can also be used to induce a difference in the refractive indices within the material. As indicated above, the orientation of the films according to the invention can be in more than one direction, and can be sequential or simultaneous.

As an example, the components of the continuous and dispersed phases can be extruded so that the dispersed phase is similar to a rod on an axis in the non-oriented film. Rods with a high aspect ratio can be generated by orientation in the direction of the major axis of the rods in the extruded film. Plate-like structures can be generated by orientation in a direction orthogonal to the major axis of the rods in the extruded film.

The structure in FIG 2 can be produced by asymmetric biaxial orientation of a mixture of spherical particles essentially within a continuous matrix. Alternatively, the structure can be obtained by incorporating a plurality of fibrous structures in the matrix material, aligning the structures along a single axis, and orienting the mixture in a direction transverse to that axis. Yet another method for obtaining this structure is by controlling the relative viscosities, shear stress, or surface tension of the components of a polymer mixture to obtain a fibrous dispersed phase when the mixture is molded by extrusion into a film. In general, it is found that the best results are obtained when the shear stress is applied in the direction of extrusion.

Dimensional Alignment of Scattered Phase The dimensional alignment is also found to have an effect on the scattering behavior of the dispersed phase. In particular, it has been observed in the optical bodies made according to the present invention that the aligned dispersers do not scatter light symmetrically near the directions of the transmission or specular reflection since the dispersers are randomly aligned. In particular, inclusions that have been lengthened by the orientation resembling the rods scatter light mainly at the end of (or near) the surface of a cone centered in the direction of orientation and along the the direction transmitted in a specular manner. This can result in an anisotropic distribution of light scattered near the directions of specular reflection and specular transmission. For example, for the incident light on the elongated rod in a direction perpendicular to the direction of orientation, the scattered light appears as a band of light in the plane perpendicular to the direction of orientation with an intensity that decreases with increasing angle outside of the specular directions. Due to the adaptation of the geometry of the inclusions, some control over the distribution of scattered light can be achieved, both in the transmissible hemisphere and in the reflective hemisphere.

Dimensions of the Scattered Phase In applications where the optical body is used as a low loss reflective sorber, the structures of the dispersed phase preferably have a high dimensional proportion, i.e. the structures are substantially large in one dimension than in any other dimension. The dimensional ratio is preferably at least 2, and more preferably at least 5. The largest dimension (i.e., the length) is preferably at least 2 times the wavelength of the electromagnetic radiation over the range of wavelength of interest, and more preferably at least 4 times the desired wavelength. On the other hand, the smaller dimensions (ie, the cross section) of the structures of the dispersed phase are preferably less than or equal to the wavelength of interest, and more preferably less than 0.5 times the length Wave of interest.

Fraction Volume of the Dispersed Phase The volume fraction of the dispersed phase also affects the scattering of light in the optical bodies of the present invention. Within certain limits, increasing the volume fraction of the dispersed phase tends to increase the amount of scattering that a light beam experiences after it enters the body for both directions of polarized light equality and inequality. This factor is important to control the reflection and transmission properties for a given application. However, if the volume fraction of the dispersed phase becomes too large, the scattering of light may decrease. Without wanting to be bound by theory, this seems to be due to the fact that the particles of the dispersed phase are more closed together, in terms of the wavelength of the light, so that the particles tend to act together for a smallest number of large effective particles.

The desired volume fraction of the dispersed phase will depend on many factors, including the specific choice of materials for the continuous or dispersed phase. However, the volume fraction of the dispersed phase will typically be at least about 1% by volume relative to the continuous phase, preferably within the range of about 5 to about 15%, and more preferably within the range of about 15 up to about 30%.

Thickness of the Optical Body The thickness of the optical body is also an important parameter, which can be manipulated to affect the reflection and transmission properties in the present invention. Since the thickness of the optical body increases, it also increases the diffuse reflection, and decreases the transmission, both specular and diffuse. Therefore, while the thickness of the optical body will typically be chosen to achieve a desired degree of mechanical strength in the finished product, it can also be used directly to control the reflection and transmission properties.

The thickness can also be used to make final adjustments in the reflection and transmission properties of the optical body. Therefore, for example, in the film applications, the device used to extrude the film can be controlled by a downstream optical device, which measures the transmission and reflection values in the extruded film, and which varies the thickness of the film (i.e., by adjusting the extrusion rates or changing the speeds of the casting wheel) to maintain the reflection and transmission values within the predetermined range.

Materials for the Continuous / Dispersed Phases Many different materials can be used as the continuous or dispersed phases in the optical bodies of the present invention, depending on the specific application to which the optical body is directed. Such materials include inorganic materials such as silica-based polymers, organic materials such as liquid crystals., and polymeric materials, including monomers, copolymers, grafted polymers, and mixtures or combinations thereof. The exact choice of materials for a given application will be carried by the desired equality and inequality obtainable in the refractive indices of the continuous and dispersed phases along a particular axis, as well as the physical properties desired in the resulting product. However, the materials of the continuous phase will generally be characterized as being substantially transparent in the region of the desired spectrum.

An additional consideration in the choice of materials is that the resulting product must contain two distinct phases. This can be achieved by melting the optical material from two or more materials, which are immiscible with each other. Alternatively, if it is desired to manufacture an optical material with a first and second material, which are not immiscible with each other, and if the first material has a higher melting point than the second material, in some cases it may be possible to fix particles of dimensions of the first material within a fused matrix of the second material at a temperature below the melting point of the first material. Then the resulting mixture can be molded into a film, with or without subsequent orientation, to produce an optical device.

The polymeric materials suitable for use as the continuous or dispersed phase in the present invention may be amorphous, semi-crystalline, or crystalline polymeric materials, including materials made from carboxylic acid-based monomers such as isophthalic, azelaic, adipic, sebasic acids , dibenzoic, terephthalic, 2,7-naphthalenedicarboxylic, 2, 6-naphthalenedicarboxylic, cyclohexanedicarboxylic, and bibenzoic (including 4,4'-benzoic acid), or materials made from corresponding esters of the aforementioned acids (ie, dimethylterephthalate). Of these, 2-6-polyethylene naphthalate (PEN) is particularly preferred, due to its stress-induced birefringence, and because of its ability to permanently maintain the birefringent after stretching. The PEN has a refractive index for the polarized incident light of 550 nm wavelength, which increases after stretching when the plane of polarization is parallel to the stretch axis of about 1.64 to as high as about 1.9, while the Refractive index decreases by polarized light perpendicular to the stretch axis. The PEN exhibits a birefringence (in this case, the difference between the reaction index along the direction of stretching and the index perpendicular to the direction of stretching) from 0.25 to 0.40 in the visible spectrum. Birefringence can be increased by increasing molecular orientation. The PEN can be substantially heat stable from about 155 ° C to about 230 ° C, depending on the processing conditions used during the manufacture of the film.

Polybutylene naphthalate is also a suitable material, as well as other dicarboxylic polyesters of crystalline naphthalene. The crystalline naphthalate dicarboxylic polyesters exhibit a difference in the refractive indices associated with the different plane axes of at least 0.05 and preferably above 0.20.

When the PEN is used as a phase in the optical material of the present invention, the other phase is preferably polymethylmethacrylate (PMMA) or an aromatic vinyl syndiotactic polymer, such as polystyrene (sPS). Other preferred polymers for use with PEN are based on terephthalic, isophthalic, sebacic, azelaic or cyclohexanedicarboxylic acid or the referred alkyl esters of these materials. The naphthalene dicarboxylic acid can also be used in smaller amounts to improve the adhesion between the phases. The diol component can be ethylene glycol or a diol referred to. Preferably, the refractive index of the selected polymer is less than about 1.65, and more preferably, less than about 1.55, although a similar result may be obtainable using a polymer having a higher refractive index if the same is achieved. refractive index.

Syndiotactic vinyl aromatic polymers useful in the present invention include poly (styrene), poly (alkyl styrene), poly (styrene halide), poly (alkyl styrene), poly (vinyl ester benzoate), and these hydrogenated polymers and blends, or copolymers containing these structural units. Examples of poly (alkyl styrenes) may be mentioned, which include: poly (methyl styrene), poly (ethyl styrene), poly (propyl styrene), poly (butyl styrene), poly (styrene) phenyl), poly (vinyl naphthalene), poly (vinyl styrene), and poly (acenaphthalene). As for the poly (styrene halides), examples include: poly (chlorostyrene), poly (bromostyrene), and poly (polyfluorostyrene). Examples of the poly (alkoxy styrene) include: poly (methoxy styrene) and poly (ethoxy styrene). • Among these examples, it may be mentioned that preferable styrene group polymers are: polystyrene, poly (p-methyl styrene), poly (m-methyl styrene), poly (p-tertiary butyl styrene), poly ( p-chlorostyrene), poly (m-chlorostyrene), poly (p-fluorostyrene), and copolymers of styrene and p-methyl styrene.

Further, vinyl aromatic group copolymer monomers, in addition to styrene group polymer monomers set forth above, may be mentioned as olefin monomers such as ethylene, propylene, butene, hexene, or octene; diene monomers such as butadiene, isoprene; polar vinyl monomers such as cyclic diene monomer, methyl methacrylate, maleic acid anhydride, or acetonitrile.

The syndiotactic vinyl aromatic polymers of the present invention may be blocked copolymers, random copolymers, or alternative copolymers.

The vinyl aromatic polymer having a high level syndiotactic structure referred to in this invention generally includes polystyrene having syndiotacticity of greater than 75% or more, as determined by carbon nuclear magnetic resonance 13. Preferably, the degree of syndiotacticity is greater than 85%, racemic diad, or greater than 30%, or more preferably, greater than 50%, racemic pentad.

In addition, although there are no particular restrictions with respect to the molecular weight of this syndiotactic vinyl aromatic group polymer, preferably, the average molecular weight is greater than 10,000 and less than 1,000,000, and more preferably, greater than 50,000 and less that 800,000.

As for other resins, various types may be mentioned, including, for example, polymers of vinyl aromatic group with atactic structures, vinyl aromatic group polymers with isotactic structures, and all polymers that are miscible. For example, the polyphenylene ethers show good miscibility with the vinyl aromatic group polymers previously discussed. In addition, the composition of these miscible resin components is preferably between 70 to 1% by weight, or more preferably, 50 to 2% by weight. When the composition of the miscible resin component exceeds 70% by weight, degradation by heat resistance may occur, and is usually not desirable.

The polymer selected for a particular phase is not required to be a copolyester or copolycarbonate. Vinyl polymers and copolymers made from monomers such as vinyl naphthalenes, styrenes, ethylene, maleic anhydride, acrylates, and methacrylates can also be employed. Condensation polymers, different from polyesters and polycarbonates, can also be used. Suitable condensation polymers include polysulfones, polyamides, polyurethanes, polyamic acids, and polyimides. The naphthalene and halogen groups such as chlorine, bromine and iodine are useful in increasing the refractive index of the selected polymer to the desired level (1.59 to 1.69) if it is necessary to substantially equal the refractive index if the PEN He is the guest. The acrylate and fluoro groups are particularly useful in decreasing the refractive index.

The minor amounts of the comonomers can be substituted in the polyester of naphthalene dicarboxylic acid, while the difference of the large refractive index in the direction (s) of orientation substantially does not settle. A smaller index difference (and therefore decreased reflectivity) can be balanced by the advantages in any of the following: improved adhesion between the continuous phase and the dispersed phase, low extrusion temperature, and better equality of melt viscosities .

Spectrum Region While the present invention is often described herein with reference to the visible region of the spectrum, various embodiments of the present invention can be used to operate at different wavelengths (and therefore frequencies) of electromagnetic radiation by means of a appropriate adjustment of the components of the optical body. Therefore, since it increases the wavelength, the linear size of the components of the optical body can be increased so that the dimensions of these components, measured in units of wavelength, remain approximately constant.

Of course, a greater effect of changing the wavelength is that, for most of the materials of interest, the refractive index and the absorption coefficient change. However, the principles of equality and inequality of the index still apply to each wavelength of interest, and can be used in the selection of materials for an optical device that will operate over a specific region of the spectrum. Therefore, for example, the proper adjustment of the dimensions will allow operation in the infrared, almost ultraviolet and ultra violet regions of the spectrum. In these cases, the refractive indexes refer to the values at these wavelengths of operation, and the thickness and size of the body of the scattering components of the dispersed phase should also be approximately adjusted for the wavelength. Even, most of the electromagnetic spectrum can be used, including very high, ultra high, microwave and millimeter wave frequencies. The effects of polarization and diffusion will be present with the proper adjustment to the wavelength and the refractive indices can be obtained from the square root of the dielectric function (including the real and imaginary parts). Useful products in these longer wavelength bands can be diffuse reflective polarizers and partial polarizers.

In some embodiments of the present invention, the optical properties of the optical body vary across the wavelength band of interest. In these embodiments, the materials can be used for the continuous and / or dispersed phases whose refractive indices, along one or more axes, vary from one region of wavelength to another. The choice of materials for the continuous and dispersed phase, and the optical properties (ie, scattered and diffuse reflection or specular transmission) that result from a specific choice of materials, will depend on the wavelength band of interest.

Surface layers A layer of material which is substantially free of a dispersed phase may be coextensively placed on one or both of the larger surfaces of the film, ie, the extruded mixture of the dispersed phase and the sonuous phase. The composition of the layer, also called a surface layer, may be chosen, for example, to protect the integrity of the dispersed phase within the extruded mixture, to add mechanical or physical properties to the final film or to add optical functionality to the final movie. Suitable materials of choice may include the material of the continuous phase or the material of the dispersed phase. Other materials with a melt viscosity similar to the extruded mixture may also be useful.

A surface layer or layers can reduce the wide range of shear intensities, which extruded mixture could be experienced in the extrusion process, particularly in the matrix. A medium of high shear stress can cause undesirable surface vacuum and can result in a textured surface. A wide range of shear values throughout the thickness of the film can also prevent the dispersed phase from forming the desired particle size in the mixture.

A surface layer or layers can also add physical strength to the resulting composite or reduce problems during processing, such as, for example, reducing the tendency to split the film during the orientation process. The materials of the surface layer which remain amorphous may tend to produce films with a greater roughness, while the materials of the surface layer which are semicrystalline may tend to produce films with a larger extensible module. Other functional components such as antistatic additives, ultraviolet UV absorbers, dyes, antioxidants and pigments, can be added to the surface layer, does not substantially provide interference with the optical properties of the resulting product.

The surface layers can be applied to one or two sides of the extruded mixture at some point during the extrusion process, i.e. before the extruded mixture and the surface layer (s) leave the extrusion die. This can be done using conventional co-extrusion technology, which can include the use of a 3-layer co-extrusion matrix. Lamination of the surface layer (s) for a preformed film of an extruded mixture is also possible. The thicknesses of the total surface layer can range from about 2% to about 50% of the total surface layer / mixture thickness.

A wide range of polymers are appropriate for the surface layers. Predominantly amorphous polymers include copolyesters based on one or more of terephthalic acid, 2,6-naphthalene dicarboxylic acid, phthalic acid of isophthalic acid, or their alkyl ester counterparts, and alkylene diols, such as ethylene glycol. Examples of semicrystalline polymers are 2,6-polyethylene naphthalate, polyethylene terephthalate, and nylon materials.

Anti-reflection layers The films and other optical devices made according to the invention can also include one or more anti-reflective layers. Such layers, which may or may not be sensitive to polarization, serve to increase transmission and reduce reflective intense light. An anti-reflective layer can be imparted to the films and optical devices of the present invention by means of appropriate surface treatment, such as coating or chemical etching by spraying with liquid expelled from the mouth.

In some embodiments of the present invention, it is desired to maximize the transmission and / minimize the specular reflection for certain polarizations of light. In these embodiments, the optical body may comprise two or more layers in which at least one layer comprises an antireflection system in close contact with a layer providing the continuous and dispersed phases. Such an anti-reflection system acts to reduce the specular reflection of the incident light and increases the amount of incident light entering the portion of the body comprising the continuous and dispersed layers. Such a function can be performed by a variety of means well known in the art. Examples are one-quarter wave antireflection layers, two or more layer antireflective layers, engraved index layers, and layers of recorded density. Such antireflection functions can also be used on the transmitted light side of the body to increase the transmitted light if desired.

Microvacuum In some embodiments, the materials of the continuous and dispersed phases may be chosen so that the interface between the two phases will be sufficiently weak to result in a vacuum when the film is oriented. The average dimensions of the empty spaces can be controlled by means of the careful manipulation of the processing parameters and stretching proportions, or by means of the selective use of the compatibilizers. The empty spaces can be filled in the finished product with a liquid, gas or solid. The vacuum can be used in conjunction with the dimensional proportions and the refractive indices of the continuous and dispersed phases to produce the desired optical properties in the resulting film.

More Than Two Phases The optical bodies made according to the present invention can also consist of more than two phases. Therefore, for example, an optical material made according to the present invention can consist of two different phases dispersed with the sontinuous phase. The second dispersed phase could be randomly or non-randomly dispersed throughout the sonuous phase, and can be randomly aligned or aligned along a somno axis.

Optical bodies made according to the present invention may also consist of more than one sonuous phase. Thus, in some modalities, the optical body can include, in addition to a first phase sontinua and a dispersed phase, a second phase which is cosontinua in at least one dimension are the first phase sontinua. In a partisan modality, the second sontinuous phase is a material paired to a sponge, porous the sual is soextensive with the first continuous phase (i.e., the first continuous phase extends along a network of spas or channels that extend through the second phase sontinua, although it extends through a sanal network in a wet sponge). In a referred modality, the second continuous phase is in the form of a dentrítisa structure which is coextensive in at least one dimension with the first sontinuous phase.

Multisaps Combinations If desired, one or more sheets of a continuous / dispersed phase film made according to the present invention can be used in combination, or as a component in a multiple sheet film (ie, to increase reflectance). The multi-aided satin films include those of the type dessrito in the dossier WO 95/17303 (Ouderkirk et al.). In such a design, the individual sheets can be laminated or otherwise adhered together or spaced apart. In the optimum thicknesses of the phases inside the sheets they are substantially equal (it is desir, if the two sheets substantially present an equal and large number of dispersers that impinge the light along a given axis), the set it will reflect, a mass in the greater efisiensia, substantially the same bandwidth and the espestral range of the reflescence (it is desir, "band") as the individual leaves. If the optical thicknesses of the phases within the sheets are not substantially the same, the composition will be reflected through a wider bandwidth than the individual phases. A compound that combines the leaves of the mirror are the sheets of the polarizer is useful to insrementar total reflestania, while still transmitted light is polarized. Alternatively, a single sheet can be asymmetrically and biaxially oriented to produce a film having polarizing and reflective selectors.

FIG. 5 illustrates an example of this embodiment of the present invention. There, the optimum body consists of a multilayer film 20 in the sual the alternative sapes between the PEN 22 sapes and the co-PEN 24 sapes. Each PEN layer includes a dispersed phase of syndiotastiso polystyrene (sPS) within a PEN matrix. This type of construction is desirable since it promotes color at a lower angle. In addition, since the separation of layers or inslusion of the averages of the dispesores out of the loss of light, the control of the thickness of the sap is less oritic, allowing the film to be more tolerable of variations in processing parameters.

Any of the previously mentioned materials can be used as any of the sapas in this modality, or we are the sontinuous or dispersed phase within a partisan sap. However, the PEN and so-PEN in particular are desirable somo greater somers of the adjacent sapas, since these materials promote good laminar adhesion.

Also, a number of variations is possible in the arrangement of the sapas. Therefore, for example, the sapas can be elaborated following a repetition sesuensia by means of a part or the whole structure. Another example of this is a construction having the layer pattern ABCABC, where A, B, and C are different materials or different combinations of the same or different materials, and wherein one or more of A, B, or C are at least one dispersed phase and at least one sonuous phase. The surface layers are preferably similar or similarly chemically similar materials.

Additives The optical materials of the present invention can also comprise other materials or additives such as cones for teas. Such materials include pigments, dyes, binders, coatings, fillers, somatizers, antioxidants (including stably hindered phenols), tensides, antimisrobis agents, anti-sestorm agents, flame retardants, foaming agents, lubricants, reinforcing agents, light stabilizers. (including ultraviolet UV stabilizers or blockers), salor stabilizers, impact modifiers, plasticizers, viscose modifiers, and other materials. In addition, the films and other optical devices made of agreement are the present invention may include one or more external sapas, the suals serve to protect the device from abrasion, impasto, or other damage, or the sual insures the prossability or durability of the device. .

Suitable lubricants for use in the present invention include salsium stearate, zin sterate, this envelope time, sobalt stearate, molybdenum neodosanoate, and ruthenium (III) asethylsatonate.

Antioxidants useful in the present invention include 4,4'-thiobis- (6-t-butyl-m-sresol), 2,2'-methylenebis- (4-methyl-6-t-butyl-butylphenol), ostadesil -3,5-di-t-butyl-4-hydroxyhydrosinnamate, bis- (2,4-di-t-butylphenyl) pentaerythritol diphosphite, Irganox ™ 1093 (1979) (crude phosphoniso ester ((3, 5) -bis (1,1-dimethylethyl) -4-hydroxyphenyl) methyl) -diostadesyl), Irganox ™ 1098 (N, N'-1,6-hexanediylbis (3,5-bis (1,1-dimethyl) -4- hydroxy-bensenpropanamide), Naugaard ™ 445 (aryl amine), Irganox ™ L 57 (alkylated diphenylamine), Irganox ™ L 115 (sulfur that are bisphenol), Irganox ™ LO 6 (alkylated phenyl-delta-naphthylamine), Etanox 398 ( fluorophosphonate), and 2,2'-ethylidenebis (4,6-di-t-butylphenyl) fluorophositite.

A group of antioxidants that are especially preferred are sterically hindered phenols, including butylated hydroxytoluene (BHT), Vitamin E (di-alpha-tocopherol), Irganox ™ 1425WL (bis- (O-ethyl (3, 5-di -t-butyl-4-hydroxybenzyl)) phosphonate of salsium), Irganox ™ 1010 (tetrakis (methylene (3,5-di-t-butyl-4-hydroxyhydrosinnamate)) methane), Irganox ™ 1076 (3, 5-di) -tert-butyl-4-hydroxyhydrosinnamate of ostadesyl), Etanox ™ 702 (hindered bis phenosis), Etanox 330 (hindered phenoxine of high molecular weight), and Etanox ™ 703 (hindered phenolic amine).

Dichroic dyes are a particularly useful additive in some applications to which the optical materials of the present invention can be directed, due to st. Ease to absorb the light of a partisan polarization subara are aligned in a way to disturb inside the material. When used in the film or other material which predominantly disperses only one polarization of light, the dye disroiso sausa that the material absorbs one polarization more than another. Dichroic dyes suitable for use in the present invention include Congo Red (sodium diphenyl-bis-alpha-naphthylamine sulfonate), methylene blue, stilbene dye (Color Index (Cl) ----- 620) , and 1,1'-diethyl-2,2'-synanine chloride (Cl = 374 (orange) or Cl = 518 (blue)). The properties of these dyes, and methods of manufacturing them, are described in E.H. Land, Colloid Chemistry (1946). These dyes have remarkable dichroism in polyvinyl alcohol and a lower dichroism in the selulosa. A slight disroism is observed with Congo Red in PEN.

Other adesuted dyes include the following materials: The properties of these dyes, and methods of manufacturing them, are discussed in the Kirk Othmer Ensyslopedia of Chemisal Teshnology, Vol. 652-661 (Fourth Edision, 1993), and in the referensias here.

When a disrodysal dye is used in the optical bodies of the present invention, it can be incorporated in either the sonless or dispersed phase. However, it is preferred that the disrodion dye insorpore in the dispersed phase.

The dissolvable dyes in symbiosis are siertos polymer systems exhibits the fasilidad to polarize the light until varying the degrees. The polyvinyl alcohol and the disodium dyes can be used to make films are the fascility to polarize the light. Other polymers, such as polyethylene terephthalate or piliamides, such as nylon 6, do not exhibit good ability to polarize light when combined with dichroic dye. The combination of the polyvinyl alcohol and the disrodysal dye is designed to have a greater disrodistic propulsion than, for example, the same dye in another film forming the polymer systems. A greater disroism propsion indicates a greater fascility to polarize light.

The molar alignment of a disrodysal dye within an optimized body of agreement is the present invention preferably is performed by stretching the optimal body after the dye has been insorporated in this. Nevertheless, other methods can also be used to achieve molecular alignment. Therefore, in one method, the disroxy dye is crystallized, either by sublimation or by crystallization from a sol- ution, in a series of elongated sorts that are sorted, recorded, or otherwise formed in the superfi- a film or other optimal body, either before or after the optimal body has been oriented. Then the treated surface can be resurfaced by one or more superfisial sapas, it can be insorporated in a polymer matrix or used in a multilayer casing, or somo somponent of another optic can be used. The sortes can be created according to a certain pattern or diagram, and with a predetermined amount of spacing between the cuts, to achieve the desired optical properties.

In a referred embodiment, the disrodysal dye may be solved within one or more bone fibers or other dyes, either before or after the fibers or hollow ducts are solved within the optic body. Fibers or bonded bones can be built out of a material that is the same or different from the sundand material of the optimal body.

In yet another embodiment, the dichroic dye colossates along the layer interface of a multilayer construction, such as by sublimation of the surface of a sap before it is insorporated in the multispassing structure. In yet other embodiments, the disrodysal dye is used to at least partially fill the spasios vasios in a misovaciated pelvis made in accordance with the present invention.

Applications of the Present Invention The optical bodies of the present invention in particular are useful as diffuse polarizers. However, the optical bodies are also elaborated according to the inventions the suals operate as reflective polarizers or diffuse mirrors. In these applications, the sonussion of the opti- mal material is similar to that in the diffuser aplissations previously dis- creted. However, these reflectors will generally have a greater difference in the reflectance index along at least one axis. This indistinct difference is typically at least 0.1, more preferably about 0.15, and more preferably about 0.2.

Reflective polarizers have a difference in refractive index along one axis, and substantially equalized along another. The reflective films, on the other hand, differ in refraction indices along at least two orthogonal plane axes in film.

However, the reflexive properties of these modalities need not be explored solely for the sake of the inequalities of the refraction index. Therefore, for example, the thickness of the films must be adjusted to provide a desired degree of reflection. In some cases, adjusting the thickness of the film may cause it to change from a transmissive diffuser to a diffuse reflector.

The reflective polarizer of the present invention has many different applications and is particularly useful in liquid crystal display panels. In addition, the polarizer can be built from PEN or similar materials, the suals are good ultraviolet light filters and the suals absorb the ultraviolet light in an efisient way up to the edge of the visible thickener. The reflective polarizer can also be used as a thin infrared sheet polarizer.

Point of View of the Examples The following examples illustrate the production of various optical materials according to the present invention, as well as spectral properties of these materials. With the exception of a sonic indication, the somposision in by sorry refers to the somposission in by I feel for weight. The polyethylene naphthalate resin used was produced for these samples using ethyleneglisol and dimethyl-2,6-naphthalenedisarboxylate, available from Amoso Corp., Chisago, Illinois. These retannages are polymerized to various intrinsic visuosities (IV) using conventional polyester resin polyacrylate rubbers. The syndiotate polystyrene (sPS) can be produced according to the method described in the U.S. patent. 4,680,353 (Ishihara et al.). The examples include various parts of polymer, various continuous and dispersed phase fractions and other additives or fillers.

Stretching or orienting the samples is provided using either conventional orientation equipment used to fabricate the polyester film or a laboratory batch orientator. The laboratory batch former used is designed to use a small piece of molten material (7.5 sm per 7.5 cm.) Cut from the extruded molten lamella and assisted by a square set of 24 fasteners (6 on each side). The orienteering temperature of the sample is sonrola by an outgoing air fan and the film sample is oriented by means of a mechanical system that increases the distance between the fasteners in one or both directions to a sonorous propulsion. The stretched samples in both directions should be oriented in a sesuensial or simultaneous manner. For samples that are oriented in forced mode (s), all fasteners maintain the movement of the lamella and fasteners in one dimension. While, in the unforced ear (U), the fasteners holding the pelvis in a dimension fixed perpendicular to the direction of stretching are not required and the film is allowed to relax or the extrusion section in that direction is relaxed.

Polarized diffuse transmission or reflection is measured using an ultraviolet / visible / near infrared spectrophotometer Perkin Elmer Lambda 19 equipped with a 150 mm integral sphere actuator Perkin Elmer Labsphere S900-1000 and a Glan-Thompson sub-loader. The values of transmission and parallel or transverse reflection are measured are the vestor e of the polarized light parallel or perpendicular, respectively, to the stretching direction of the film. All explorations are sontinua and are carried to sabo are a scan ratio of 480 nanometers per minute and a slot width of 2 nanometers. The reflection is done in the "reflection V" mode. Transmission and reflectance values are averages of all wavelengths from 400 to 700 nanometers.

EXAMPLE 1 In example 1, an optical film is elaborated according to the invention by extrusion of a mixture of 75% polyethylene naphthalate (PEN) as the sontinuous phase or greater and 25% of poly'-netilmetasrilato (PMMA) as the phase dispersed or smaller in a pellet or cast sheet of approximately 380 thicknesses using conventional extrusion and casting tessellations. The PEN has an intrinsic (IV) visosity of 0.52 (measured in 60% phenol, 40% dislorobensen). PMMA is obtained from ICI Amerisas, Ins., Wilmington, Delaware, under the designation of produsto CP82. The used extruder is a Brabender of 3.15 sm (1.24 inches) is a 60 μm Tegra filter from a tube. The matrix is an EDI Ultraflex ™ 40 of 30.4 sm (12 inches).

Approximately 24 hours after the film is extruded, the cast film is oriented in width or cross direction (TD) is a polyester film elongation device. Stretching at approximately 9.1 meters per minute (30 ft / min) is an exit gap of approximately 140 sm (55 inches) and a stretch temperature of approximately 160 ° C (320 ° F). The total reflectance of the stretched sample is measured in a single-dial integral in a spectrophotometer. Lambda 19 are the polarized sample beam are a Glan-Thompson subo polarizer. The sample has a parallel reflectance of 75% (ie, the reflectivity is measured are the stretch tension of the film parallel to the vestor of the polarized light), and transverse reflectivity of 52% (ie, the reflectivity is measured with vector e of polarized light perpendicular to the direction of stretching).

EXAMPLE 2 In Example 2, an optical film is processed and evaluated in a manner similar to Example 1, which is used in a mixture of 75% PEN, 25% polystyrene syndiotate (sSP), 0.2% of a glisidyl metasillate somatibilizer of polystyrene, and 0.25% of sada one of Irganox ™ 1010 and Ultranox ™ 626. The synthesis of polystyrene glisidyl methacrylate is dessribe in the Prosesos de Polímero, "Chemisal Teshnology of Plastics, Resins, Rubbers, Adhesives and Fibers", Vol 10, Chapter 3, pp. 69-109 (1956) (Ed. By Calvin E. Schildknesht).

The PEN have an intrinsic viscosity of 0.52 measured in 60% phenol, 40% dichlorobenzene. The sSP is obtained from Dow Chemisal Co. and has an average weight average of approximately 200,000, designated in a subsysuent manner as sSP-200-0. The parallel reflectance in the stretched-film sample is determined to be 73.3% and the transverse reflectivity is determined to be 35%.

EXAMPLE 3 In Example 3, an optical film is processed and evaluated in a manner similar to Example 2, except that the level of compaitibilizer is increased to 0.6%. The resulting parallel reflectance is determined to be 81% and the transverse reflectance is determined to be 35.6%.

EXAMPLE 4 In Example 4, a three-layer optics film is elaborated according to the present invention using so-extrusion tresses from three sonovsional sapes. The film has a layer of nuscle and a superfisial sapa on the side of the core sap. The core layer consists of a mixture of 75% PEN and 25% of sSP-200-4 (the designation sSP-200-4 refers to a copolymer of polystyrene syndiotate which is 4% mol of styrene of paramethyl), and sap superfisial sap consists of 100% PEN having an intrinsic viscosity of 0.56 measured in 60% phenol, 40% dichlorobensen.

The resulting three-layer cast film has a core layer thickness of about 415 millimeters, and a superfisial sap is approximately 110 millimeters of thickness for a total thickness of about 635 millimeters. A laboratory batch stretcher is used to stretch the three-layer melt pellet resulting in about 6 to 1 in the machine direction (MD) at a temperature of about 129 ° C. Because the edges of the film sample parallel to the stretch direction are not held by the laboratory fastener, the sample is not forced in the transverse direction (TD) and the sample is reduced in the extrusion section in the TD approximately 50% as a result of the stretching procedure.

The optical performance is evaluated in a manner similar to Example 1. The parallel reflectivity is determined to be 80.1%, and the transverse reflectivity is determined to be 15%.

These results show that the film is made by a system of energy preservation, of low absorption.

EXAMPLES 5-29 In Examples 5-29, a series of optical films are produced and evaluated in a manner similar to Example 4, which shows that the flush of sPS in the nick and the IV of the PEN resin used is varied as shown in FIG. Table 1. The IV of the PEN resin in the sap of nuscle and that in the superfisial sapas is the same for a given sample. The total thickness of the cast sheet is approximately 625 mm, approximately two threads of this total in the sheet metal and the balance in the surface layers, which are approximately equal in thickness. Several mixtures of PEN and sPS in the core layer are produced, as indicated in Table 1. The films are stretched to a stretch ratio of approximately 6: 1 in either the machine (MD) or in the diression Cross section (TD) at various temperatures is indicated in Table 1. Some of the samples are forced (C) in the direction perpendicular to the stretch direction to prevent the redussion sample from the extrusion session during stretching. The "U" blank samples in Table 1 are unforced and the extrusion section is allowed to be redrawn in the unforced dimension. Certain optical properties of the stretched samples, including transmission, reflection, and absorption in per cent, are measured along axes both parallel and transverse or perpendicular to the stretching direction. The results are summarized in the Table The medium of salor, as indicated by Examples 24-27, is performed manually by forcing the two edges of the stretched sample, the suals are perpendicular to the stretching direction by holding a rigid shell in size appropriately and soldering the clamped sample in an oven at the temperature indicated for 1 minute. The two sides of the sample parallel to the stretching direction are unforced (U) or do not hold and allow the restriction section to be reduced. The heat medium of Example 29 is similar, except that all four edges of the stretched sample are unforced (C) or clamped. Example 28 is not a heat equipment.

All the above samples are observed to contain variant forms of the dispersed phase depending on the localization of the dispersed phase within the body of the pellet sample. The insides of the scattered phase, which are closest to the superfisies of the samples, are observed to be of an elongated form rather than being more spherical. The insides, which are approximately more centered between the surfaces of the samples, may be more spherical. This is true for the samples are the superfisial sapas, but the magnitude of the efesto reduse are the superfisial saps. The adduction of the superfisial layers mejera the processing of the films reducing the tendency to unfolding during the stretching operation.

Without wishing to be bound by theory, the stretching of the inclusions (dispersed phase) in the nickel sape of the molten film is by the result of the shear stress in the mixture as it is transported through the matrix. This stretching sarasteristisa can be altered by varying the physical dimensions of the matrix, extrusion temperatures, flow propulsion of extruded material the sual would alter its relative fusion visosities. Certain applications or uses can be benefited by providing some stretching to the dispersed phase during extrusion. For those aplissations which are subsequently stretched in the machine direction, inisia being the dispersed phase stretched during extrusion can maintain a higher dimensional propulsion that is achieved in the resulting dispersed phase.

Another notable sarasteristisa is hesho that a remarkable improvement in performance is observed when the same sample is not subjected to an elongated effort. Therefore, in Example 9, the% transmission is 79.5% and 20.3% in the parallel and perpendicular directions, respectively. By contrast, the transmission in Example 16 is only 75.8% and 28.7% in the parallel and perpendicular directions, respectively. There is an instement of thickness in relasion to forced stretching when the samples are subjected to an elongation effort, but since it improves both the transmission and extrusion, it probably improves the equality of the index.

An alternative way to improve the control of the refraction index is to modify the materials' chemisa. For example, a sopolymer of 30% by weight of interpolymerized units derived from terephthalic acid and 70% by p > that of units derived from rough 2, 6-naphthalism has a refractive index of 0.02 units less than a 100% PEN poly. Other monomers or propions may have slightly different results. This type of sambio can be used to stress the indices of refraction on an axis, while only a slight reduction in the axis is caused, the sual wants a big difference. In other words, the benefits are more stressed by the equality of the values of the index on one axis than by the sompensar redussión on an orthogonal axis in the sual a great difference is desired. Second, a quimical sambio may be desirable to alter the temperature range in the sual stretching occurs. A sPS sopolymer and varying styrene monomer proprimetions of paramethyl will alter the temperature range of the optimal stretch. A symbiosis of these theses may be necessary in order to more effectively optimize the total system for the prosecution and resulting equalities and refractive index differences. Therefore, an improved control of the final performance can be achieved by optimizing the process and chemistry in terms of stretching conditions and also by adjusting the material thickness and material to maximize the difference in the refractive index in at least one axis and minimizing the difference in at least one orthogonal ej ej.

These samples represent better optical performance if oriented in the MD rather than the TD direction (compared in Examples 14-15). Without wishing to be bound by theory, it is believed that inclusions of different geometry are developed with an MD orientation that are a TD orientation and that these insides have larger dimensional propsions, making less important non-ideal end efests. The non-ideal end efests refer to the replenishment of the somplej / indise geometry of refraction at the tip of the end sada of the elongated partisans. The interior or non-final points of the particles are believed to have a uniform geometry and an index of refraction the sual is believed to be desirable. Therefore, the greater percentage of the stretched particle that is uniform, improves the optimal performance.

The extinction propulsion of these materials is the propulsion of the transmission for polarizations perpendicular to the direction of stretching to that parallel to the direction of stretching. For the examples cited in Table 1, the extinction ratio ranges from about 2 to about 5, although the extinction ratios up to 7 have been observed in optical bodies made according to the present invention. It is expected that the extinction rates can be achieved by adjusting the thickness of the film, the inclusion volume fraction, the size of the particle, and the degree of equality and inequality of the index.

EXAMPLES 30-100 In Examples 30-100, the samples of the invention are made using various materials as listed in Table 2. The PEN 42, PEN 47, PEN 53, PEN 56, and PEN 60 refer to the polyethylene terephthalate having a intrinsic viscosity (IV) of 0.42, 0.47, 0.53, 0.56, and 0.60, respectively, measured in 60% phenol, 40% dislorobensen. The used partisan sPS-200-4 is obtained from Dow Chemisal Co. The Ecdel ™ 9967 and Eastar ™ are copolyesters which are commercially available from Eastman Chemical Co., Rochester, New York, the Surlyn ™ 1706 is an ionomer resin available from He di Pont de Nemours & Co., Wilmington, Delaware. The materials listed as Additive 1 or 2 include polystyrene glisidyl methacrylate. The designations GMAPS2, GMAPS5, and GMAPS8 refer to glisidyl metasyrilate having 2, 5, 8% by weight, resistantly, of glisidyl metasillate in the total sopolymer. ETPB refers to ethyltriphenylphosphonium bromide as a crosslinking agent. PMMA V044 refers to a polymethyl methacrylate available somersially from Atohaas North Amerisa, Ins.

The optical film was produced in a similar way to the Example 4, exsept that for the differences shown in the Table 2 and discussed below. The continuous phase and its propulsion of the total is reported as a major phase. The dispersed phase and its proportion of the total is reported as a minor phase.

The reported value for mixing thicknesses represents the approximate thickness of the surface layer in microns. The thickness of the surface sapes varies when the thickness of the core layer varies, but it is maintained at a constant rate, that is, the superfisial sapes are approximately equal and the total of the two superfisial sapas is approximately one threse of the total thickness. The size of the dispersed phase is determined by some samples by either an astronomical exploration microscope (SEM) or transmission microscope (TEM) These samples are supersistently stretched using the laboratory batch orienter shown by an "X" in the marsada elongated batch.

TABLE 2 co o 00 1- 00 INJ oo 00 00 -fc. 00 00 The presensia of the various somatizers is ensured that they reduce the size of the dispersed or insulated phase.

EXAMPLE 101 In Example 101, an optical film is made in a similar manner to Example 4, that the resulting nickel thickness is about 420 inches thick, and that the superfisial sheet is about 105 inches thick. The PEN have an IV of 0.56. The molten film is oriented as in Example 1, except that the stretching temperature is 165 ° C and it is a 15 day delay between melting and stretching. The transmission is 87.1% and 39.7% for polarized light, parallel and perpendicularly, respec- tively.

EXAMPLES 102-121 In Examples 102-121, the optical films are processed as in Example 101, except that the orientation conditions are varied and / or the sSP-200-0 is replaced with either sSP sopolymers that are either 4 or 8 % by mol of para-methyl styrene or are an atastized form of styrene, Styron 663 (available from Dow Chemical Company, Midland, Mishigan) as listed in Table 3. Transmission properties assessments are also reported. The transmission values are averaged with all wavelengths between 450-700 nm.

TABLE 3 These examples do not specify that the particles of the insulated phase are stretched in the machine direction in PEN of high IV that in PEN of low IV, the elongation is presented to a greater extension sersa of the superfisie of the film than in interior points to the Pelisula, are the result that the fibrillar stratifications are formed sersa of the superfisie and the estrérisas estrusturas are formed towards the center.

Some of these examples suggest that orienteering temperatures and the degree of orientation are important variables in achieving the desired effect. Examples 109 to 114 suggest that the required crystallization at rest is not the only reason for the lack of transmission of a preferred polarization light.

EXAMPLES 122-124 In Example 122, a multilayer optical film is made in accordance with the invention by means of a 209-ply feed block. The feeding block is fed with two materials: (1) PEN at 38.6 kg per hour (intrinsic visosity of 0.48); and (2) a mixture of 95% CoPEN and 5% by weight of sPS homopolymer (molecular weight of 200,000). CoPEN is a copolymer based on 70 mol% of naphthalene dicarboxylate and 30% in polymerized dimethyl isophthalate mold are ethyleneglisol at an intrinsic visosity of 0.59. The CoPEN / sPS mixture is fed into the feed block at a propulsion of 34.1 kg per hour.

The material of the CoPEN mixture is on the outside of the extruded material, and the composition of the layer of the resultant layer of the altered layers between the two materials. The thicknesses of the layers are designed to result in a quarter wavelength with a linear gradient of thickness, and have a ratio of 1.3 from the thinnest layer to the thickest. Then, a coarser superfisial sappa of CoPEN (elaborated in agreement) are the method described above to elaborate the CoPEN / sPS mixture, except that the molar proportions are 70/15/15 of naphthalene dicarboxylate / dimethyl terephthalate / dimethyl isophthalate ) free of sPS is added to each side of the composite of 209 layers. The total surface layer is added at a rate of 29.5 kg per hour, with about one-half of this amount on each side or surface of the pile.

The coated multilayer stack is a resulting superfisial sap is molded by extrusion through an asymmetric 1.2 ratio multiplier to achieve a multilayer composite of 421 layers. Then the resultant multilayer composite is coated with another surface layer of CoPEN 70/15/15 in sada superfisie to a total propulsion of 29.5 kg per hour are approximately one half of this sanctity on each side. Since the second superfisial sapa separately can not be detestable by the existing superfisial sap (since the material is the same), for the purposes of this dissusion, the resulting extra-thick superfisial sap will be counted as a single layer.

The resulting 421 layer composite is again molded by extrusion through an asymmetric multiplier of 1.40 of proporsion to achieve a film of 841 saps, the sual then melted into a sheet by extrusion through a die and cooling on a sheet of approximately 30 mm thick. Then the resulting cast sheet is oriented in the direction of anchors using an elongation device for the fabrication of a sonorse film. The sheet is stretched at a temperature of about 300 ° F (149 ° C) to a stretch propration of about 6: 1 and a stretch propulsion of about 20% per second. The resulting stretched film is approximately 5 millimeters thick.

In Example 123, a multi-sheet optical film is made as in Example 122, except that the amount of sPS in the CoPEN / sPS mix is 20% instead of 5%.

In Example 124, a multi-sheet optical film is processed as in Example 122, which is not adhered to the sPS film.

The results reported in Table 4 include a measure of the optical gain of the film. The ganansia of the film is the propulsion of the light transmitted through an LCD panel of a background illumination are the film inserted between the two in the light transmitted without the film in its proper place. The importance of optimal ganisation in the context of optical films is disclosed in WO 95/17692 in rejection to FIG. 2 of that referendum. A higher rate of ganasia is usually desirable. The transmission values include the values obtained when the light source is polarized parallel to the stretching direction (T) and polarized light perpendicular to the stretching direction (T,). The out-of-angle solor (OAC) is measured using an Oriel spectrometer as the mean square root deviation of p-polarized transmission at 50 degrees of incident light of wavelength between 400 and 700 nm.

TABLE 4 The out-of-angle color value (OAC) demonstrates the advantage of using a multilayer construsion in the context of the present invention. In particular, such a construct can be used to substantially reduce OAC with only a modest reduction in ganglia. This somercialization may have advantages in some applications. Light scattered by the scattered phase of sPS can not be received by the detector.

The presedent description of the present invention is merely illustrative, and is not intended to be limiting. Therefore, the scope of the present invention should only be considered referensia to the amended claims.

It should be noted that they are relasion to this fesha, the best method sounded by the solisitant to bring the invention to the test is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property.

Claims (31)

1. An optimal body, sarasterized because it includes: a first phase that has a birefringence of at least about 0.05; Y a second phase, collided within the first phase, its refraction index differs from the first phase by greater than approximately 0.05 along a first axis and by less than approximately 0.05 along a second axis orthogonal to the first axis; wherein the diffuse reflectance of the first and second phase all along the at least one axis for at least one polarization of electromagnetic radiation is at least about 30%.

2. The optical body according to claim 1, characterized in that the first phase has a birefringence of at least about 0.1, preferably at least about 0.15, more preferably at least about 0.23.

The sonorous optics body to claim 1 or 2, characterized in that the second phase has a birefringence of less than about 0.02, preferably less than about 0.01.

4. The optical body according to any one of the recesses 1 to 3, sarasterized because the second phase has a refraction index, the sual differs from the first phase by greater than about 0.1, more preferably greater than about 0.15, so more preferable by greater than approximately O2 along the first axis.

5. The optimum sonority body at any of claims 1 to 4, characterized in that the second phase has a refractive index which differs from the first phase by less than about 0.03, preferably by less than about 0.01 throughout the second. axis.

6. The optical skeleton body at any of claims 1 to 5, sarasterized in that the first and second phases taken together have a diffuse reflectivity along at least one axis of at least about 50% for both polariasions of the electromagnetic radiation.

7. The optimum sonority body to claim 1, sarasterized in that the optimum body has a total reflectance of greater than about 50%, preferably greater than about 60%, more preferably greater than about 70% for a first polarization of electromagnetic radiation and a total transmission of greater than approximately 50%, preferably greater than approximately 60%, more preferably greater than approximately 70% for a second polarization of electromagnetic radiation orthogonal to the first polarization-

8. The optimum sonority body to claim 7, which is sampled because at least about 40% of greater than about 60% polarized light orthogonal to a first light polyricing is transmitted through the opti- mal body is a deflection angle of less than about 8. °, preferably at least about 60%, more preferably at least about 70%.

9. The optical body according to claim 1 to 8, sarasterized because the first phase somprende a thermoplastic resin.

10. The optimum sound-insulating strength to claim 9, characterized in that the thermoplastic resin is an aromatic syndiotactic vinyl polymer derived from an aromatic vinyl monomer.

11. The optimum sonority body at claim 9 or 10, sarasterized because the thermoplastic resin comprises interpolymerized units of polystyrene syndiotates.

12. The optimum sonority body at claim 9 to 11, sarasterized because the thermoplastic resin contains polyethylene naphthalate.

13. The optimal sonority body to the claim 12, characterized in that the second phase comprises polystyrene syndiotates.

14. The optical body according to claim 9 up to 12, sarasterized in that the second phase also comprises at least one thermoplastic polymer.

15. The optical body according to claim 1, is sarasterized in that the optimum body is stretched to a stretch propulsion of at least about 2 to at least about 6.

16. The optimum sonority body according to claim 1 to 15, characterized in that the optical body is oriented in at least two directions.

17. The optimum sonority body at claim 1 to 16, sarasterized in that the second phase occurs at a sanity of at least about 1%, preferably from about 5% to about 50%, more preferably about 15% up to approximately 30% by volume in relasion to the first phase.

18. The optimum sonority element to any of claims 1 to 17, characterized in that the diffuse reflectance of the first and second phases taken together along at least one axis for at least one polarization of visible, ultraviolet, or infrared electromagnetic radiation is at least about 30%.

19. The optimum sonority element at any one of the claims 1-18, sarasterized because the optimum body is a film, and wherein the difference of the index between the first and second phase is less than about 0.05 along a terser axis, the sual is perpendicular to the superfisie of the film and the sual is resyprosely orthogonal to the first and second axis.

20. The optimum sonority element at any one of claims 1-19, is sarastered because the optical element is stretched in at least one direction, wherein at least about 40% of polarized light orthogonal to a first diffuse polarization of light is transmitted to Through the optical body, and in which the diffusely transmitted rays are distributed mainly along or close to the surface of a cone of the superfamily, they have the direction of transmitted specular and their axis is directed in the direction of stretching.

21. The optical signature of any of claims 1 to 21, characterized in that the optical body is a polarizing film.

22. The optical body, which is sarasterized because it comprises: a continuous phase; a dispersed phase whose refractive index differs from the continuous phase by greater than about 0.05 along a first axis; Y a dye-like dye.

23. The optimum sonority element to claim 22, characterized in that the dispersed phase has a refractive index that differs from the sonless phase by less than about 0.05 along a second axis orthogonal to the first axis.

24. The optical body according to claim 22 or 23, sarasterized because the disrodion dye solves within the dispersed phase.

25. An optimal body, characterized because it includes: a first phase that has a birefringence of at least about 0.05; Y a second phase, placed within the first phase; where the absolute value of the difference in the refraction index of the first and second phases is neither along a prime axis y? n2 along a second axis orthogonal to the first axis, where the value The absolute difference between? nx and? n2 is at least about 0.05, and wherein the diffuse reflectance of the first and second phases taken together along at least one axis for at least one polarization of the electromagnetic radiation is at least approximately 30%

26. The optimal sonority suerpo to claim 25, sarasterized because the absolute value of the difference between? Ni and? N2 is at least about 0.1.

27. The optimum sonority body at claim 25 or 26, sarasterized because the first phase has a greater birefringence than the second phase.

28. The optimal sonority body to the claim 27, sarasterized because the birefringence of the first phase is at least 0.02, preferably at least 0.05 higher than the birefringensia of the second phase.

29. An optimum sonority body at claim 25 up to 28, sarasterized because the second phase is dissonant along at least two of the three orthogonal axes resy rosamente.

30. A polarizer, sarasterized because it comprises: a first phase that has a birefringence of at least about 0.05; and a second phase, which is discontinuous along two of the three orthogonal axes resríprosamente; where the absolute value of the difference in the index of refraction of the first and second phase is? nx along a first axis and? n2 along a second axis orthogonal to the first axis, where the absolute value of the difference between? ni and? n2 is at least about 0.05, and wherein the diffuse reflectivity of the first and second phases taken together along at least one axis for at least one polarization of electromagnetic radiation is at least about 30% .

31. The polarity of the deformation to the claim 30, characterized in that it also produces a dye disroiso.