KR100676886B1 - Reflection polarized light film and display device having the same - Google Patents

Abstract

The present invention relates to a reflective polarizing film that transmits linearly polarized light in one direction among incident polarized light incident in different wavelength bands and reflects the remaining polarized light. At least one phase delay layer for converting the light into an ellipse or circularly polarized light; And a cholesteric liquid crystal layer laminated on the output side of the phase delay layer to reflect the ellipse or circularly polarized light in the incident direction.

Accordingly, there is provided a reflective polarizing film which can be easily manufactured and can reduce an optical component while improving luminance and minimizing light loss, and a display device having the same.

Polarized light, reflective polarizing film, phase delay, linearly polarized light, circularly polarized light, laminated film, liquid crystal display device, display device

Description

Reflective polarizing film and display device having same {reflection polarized light film and display device having the same}

1 is a configuration diagram of a brightness enhancement device having a conventional reflective polarizing film,

2 is a simplified cross-sectional view of the reflective polarizing film according to the first embodiment of the present invention;

3 is a simplified cross-sectional view of a reflective polarizing film according to a second embodiment of the present invention;

4 is an exploded configuration diagram of the phase delay layer of FIG. 3;

5 is a simplified cross-sectional view of an exemplary reflective polarizing film according to a second embodiment of the present invention;

6 is an exploded configuration diagram of the phase delay layer of FIG. 5;

7 is a simplified cross-sectional view of a reflective polarizing film according to a third embodiment of the present invention;

8 is a simplified cross-sectional view of a reflective polarizing film according to a fourth embodiment of the present invention;

9 is a simplified configuration diagram of a display device having a reflective polarizing film according to the present invention;

10 and 11 are simplified configuration diagrams of another form of display device having a reflective polarizing film according to the present invention.

* Explanation of symbols for the main parts of the drawings

1a-1e, A: reflective polarizing film 10a-10e: phase delay layer

20a to 20e: cholesteric liquid crystal layer 50, 50 'display device

80, 90: light diffusion layer

The present invention relates to a reflective polarizing film and a display device having the same, and more particularly, to a reflective polarizing film and a display device having the same, which can improve the brightness and reduce the optical parts, and can be easily manufactured. .

Liquid crystal (LC) displays widely used in display devices such as mobile phones, electronic calculators, notebook computers, and LCD monitors display an image using polarization in a specific direction among light applied from an electric field and a light source. For this reason, the configuration of a general liquid crystal display has a structure in which a liquid crystal and an electrode matrix are arranged between a pair of light absorbing polarizers.

However, the polarizer of a conventional liquid crystal display passes polarized light in one direction (hereinafter referred to as "P polarization") of light transmitted from the light source and absorbs light in other directions (hereinafter referred to as "S polarization"). Since it has a characteristic to dissipate, there is a problem that the brightness of the display device due to the loss of light drops sharply, causing a waste of power.

In order to solve this problem, Korean Patent Publication has disclosed a brightness enhancement device (registration number 10-0432457) having a reflective polarizing film. As shown in FIG. 1, the brightness enhancing device 101 has a structure in which a reflective polarizing film 130 is provided between the optical cavity 110 and the liquid crystal assembly 120.

The polarization separation principle of the brightness enhancing device 101 is that the P-polarized light of the light from the optical cavity 110 to the liquid crystal assembly 120 is passed through the reflective polarizing film 130 to the liquid crystal assembly 120, S The polarized light is reflected from the reflective polarizing film 130 to the optical cavity 110 and then reflected from the diffuse reflection surface 111 of the optical cavity 110 in a state in which the polarization direction of the light is randomized to reflect the polarizing film 130 again. Eventually, the S-polarized light is converted into P-polarized light that can pass through the polarizer 121 of the liquid crystal assembly 120 to pass through the reflective polarizing film 130 to be transmitted to the liquid crystal assembly 120. will be.

At this time, the selective reflection of S-polarized light and the refraction transmission of P-polarized light with respect to the incident polarization of the reflective polarizing film 130 are performed by the flat optical layer a 131 having anisotropic refractive index and the flat optical layer b having an isotropic refractive index b ( The difference in refractive index between each optical layer in the state where 133 is alternately stacked in multiple layers, the optical thickness setting of each optical layer according to the stretching process of the stacked optical layers, and the refractive index change of the optical layer a (131) Is done.

The structure of the reflective polarizing film 130 is that when the incident polarization incident on the reflective polarizing film 130 is reflected facing a refractive index difference at the boundary between the optical layers, the P polarization of the specific incident angle (Brewster angle) has a reflection coefficient. It is for utilizing the so-called Brewster effect which becomes 0 and transmits and refracts.

Due to the Brewster effect, the light incident on the reflective polarizing film 130 passes through each optical layer and repeats the reflection of the S polarization and the refractive transmission of the P polarization, and eventually only the P polarization of the incident polarization is the liquid crystal assembly 120. Is delivered to. On the other hand, the reflected S-polarized light is reflected in a state in which the polarization state is randomized at the diffuse reflection surface 111 of the optical cavity 110 and is transmitted to the reflective polarization film 130 again.

As a result, power loss can be reduced together with the loss of light generated from the light source.

By the way, the reflective polarizing film of the conventional brightness enhancement device alternately stacked anisotropic optical layer and anisotropic optical layer on the plate with different refractive indices, and by extending it, each optical that can be optimized for selective reflection and incident transmission of incident polarization Since it is manufactured to have an optical thickness and refractive index between layers, there is a problem that the manufacturing process of the reflective polarizing film is complicated.

In particular, since each optical layer of the reflective polarizing film has a flat plate structure, P-polarized light and S-polarized light must be separated to correspond to a wide range of incident angles of incident polarized light, so that the number of stacked optical layers is excessively increased, making production difficult. There is a weighted problem. In fact, looking at the embodiment of the reflective polarizing film disclosed in the patent publication (Registration No. 10-0432457), it can be seen that the number of laminated optical layers is made up of several hundred layers.

In addition, due to the structure in which the number of layers of the optical layer is excessively formed, there is a concern that the optical performance is deteriorated due to the light loss, and there is a problem that an optical component for improving the latitude of the prism sheet or the like must be further provided due to the structure using birefringence There was this.

Accordingly, an object of the present invention is to provide a reflective polarizing film and a display device having the same, which can be easily manufactured and reduce optical components, while simultaneously improving luminance and minimizing light loss.

The above object is, according to the present invention, in a reflective polarizing film that transmits linearly polarized light in one direction of incident polarizations incident on different wavelength bands and reflects the remaining polarizations, converting specific polarizations among incident polarizations into the linearly polarized light At least one phase delay layer for converting the remaining polarized light into an ellipse or circular polarized light and outputting the light; It is achieved by a reflective polarizing film comprising a cholesteric liquid crystal layer laminated on the output side of the phase delay layer to reflect the ellipse or circularly polarized light in the incident direction.

On the other hand, the above object is, according to another aspect of the present invention, in the reflective polarizing film that transmits linearly polarized light in one direction of the incident polarization incident in different wavelength bands and reflects the remaining polarization, the incident side of the incident polarization A first phase delay layer disposed to convert the incident polarization into the ellipse or circular polarization; A cholesteric liquid crystal layer laminated on the exit side of the first phase delay layer to pass polarization in one rotation direction of the ellipse or circular polarization and reflect polarization in the other rotation direction to the incidence side; And a second phase retardation layer laminated on the exit side of the cholesteric liquid crystal layer and converting the polarization in one rotational direction passing through the cholesteric liquid crystal layer into linearly polarized light in the specific direction. It is also achieved by a film.

Here, the phase delay layer is formed by stacking a plurality of retardation plates made of an organic material thin film having birefringence to cross the optical axis, and preferably phase-retards incident light in the wavelength range of 400 nm to 700 nm to a retardation value of λ / 2. Do.

In this case, the phase delay layer may be formed in such a manner that at least two retardation plates having different retardation values cross each other with an optical axis.

Alternatively, the phase delay layer may be laminated so that at least three retardation plates having the same retardation value intersect with each other.

In addition, it is preferable that at least one of the incidence side surface and the outgoing side surface of the cholesteric liquid crystal layer is formed with a refractive pattern for collecting and refracting light in a substantially vertical direction.

At this time, it is effective that the refractive pattern is a prism shape having a triangular cross section when projecting the cross section.

On the other hand, according to another field of the present invention, the liquid crystal for displaying an image using a light emitting and an optical cavity having a diffuse reflection surface at the bottom and the linearly polarized light in a specific direction of light transmitted from the optical cavity A display device having an assembly and a reflective polarizing film disposed between the optical cavity and the liquid crystal assembly and transmitting linearly polarized light in the specific direction and reflecting the remaining polarized light among incident polarizations transmitted from the optical cavity. The film is also achieved by a display device characterized in that the above-mentioned reflective polarizing film.

Here, it is preferable to include a light diffusion layer provided between the reflective polarizing film and the optical cavity.

In addition, it is effective that the light diffusion layer has diffused particles for diffusing light therein.

Further, the light diffusion layer is more preferably composed of a plurality of diffusion patterns having an optical cross section of a partial arc, and a plurality of refractive patterns having a triangular optical cross section formed along the pattern surface of the diffusion pattern.

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

2 is a simplified cross-sectional view of the reflective polarizing film according to the first embodiment of the present invention. As shown in the figure, the reflective polarizing film 1a according to the present invention converts a specific polarized light out of incident polarization into linearly polarized light and converts the remaining polarized light into an elliptic or circularly polarized light (hereinafter referred to as "circular polarized light"). A phase delay layer 10a and a cholesteric liquid crystal layer 20a stacked on the exit side of the phase delay layer 10a and passing linearly polarized light and reflecting circularly polarized light are included.

The phase delay layers 10a are fixed to each other using the adhesive material 5 so that at least two retardation plates 11a and 12a intersect the optical axes.

Each of the retardation plates 11a and 12a is manufactured in the form of a film using an organic thin film having different phase retardation values and birefringence. At this time, the organic thin film is a phase retardation by imparting birefringence to any one or a polymer of polycarbonate, polyimide, polyallylate, polyether sulfone, (alicyclic) polyolefin, poly (meth) acrylate, polyetherimide It can be produced by having a function.

The phase delay layer 10a converts specific polarizations of incident polarizations at a specific band wavelength into linearly polarized light by cross coupling of different phase delay values of the retardation plates 11a and 12a and the optical axis. Convert to circularly polarized light.

In this case, the left or right direction of the circularly polarized light may be selected by the optical axis crossing direction and the angle of the retardation plates 11a and 12a.

The cholesteric liquid crystal layer 20a has a structure in which molecular arrangements are arranged in a spiral in a very thin molecular layer. Such a structure can create a structure in which linearly polarized light is transmitted and circularly polarized light in one direction is reflected depending on the arrangement of molecules.

That is, when the molecular arrangement of the cholesteric liquid crystal layer 20a is a rightward spiral, the incident polarization of right circularly polarized light may be reflected, or when the molecular arrangement of the cholesteric liquid crystal layer 20a is a leftward spiral, The incident polarization of the leftward circularly polarized light can be reflected.

Here, the molecular arrangement direction of the cholesteric liquid crystal layer 20a is selectively set in the manufacturing step, and this setting is set to correspond to the direction of the circularly polarized light selected in the phase delay layer 10a.

That is, when the phase delay layer 10a is manufactured to convert the remaining incident polarization other than the specific polarization into the left circularly polarized light, the molecular arrangement of the cholesteric liquid crystal layer 20a is oriented in the leftward spiral. On the other hand, when the phase delay layer 10a is manufactured to convert the remaining incident polarization to the rightward circularly polarized light, the molecular arrangement of the cholesteric liquid crystal layer 20a is oriented in the rightward spiral.

With this configuration, the reflective polarization film 1a according to the present embodiment converts the specific polarization of the incident polarization of the specific band wavelength transmitted from the light source into linearly polarized light while passing through the phase delay layer 10a, and the remaining polarization is one. It is emitted in the direction circularly polarized light. The linearly polarized light of the polarization converted by the phase delay layer 10a passes through the cholesteric liquid crystal layer 20a as it is, and one-way circularly polarized light is reflected from the cholesteric liquid crystal layer 20a toward the incident side.

On the other hand, Figure 3 is a simplified cross-sectional view of the reflective polarizing film according to a second embodiment of the present invention, Figure 4 is an exploded configuration diagram of the phase delay layer of FIG. As shown in these figures, the reflective polarizing film 1b according to the present embodiment converts a specific incident polarization of linearly polarized light into linearly polarized light and converts the remaining incident polarization into circularly polarized light in one direction. and; A cholesteric liquid crystal layer 20b is laminated on the exit side of the phase delay layer 10b to pass linearly polarized light and reflect circularly polarized light.

The phase retardation layer 10b has a structure in which at least three retardation plates 11b, 12b, and 13b made of an organic material thin film having birefringence are laminated so as to cross the optical axis by the adhesive material 5, and are 400nm to 700nm. Incident light in the wavelength band of? Is delayed in phase with a delay of? / 2.

These delay plates 11b, 12b, and 13b are calculated by Stokes variables and Mueller matrices in which the optical axis angles θ of each of the delay plates 11b, 12b, and 13b have the same phase delay value β. By mutually arranged at a predetermined angle, phase polarization of incident polarization of a specific incident angle in a wavelength band of 400 nm to 700 nm, which is a relatively wide band wavelength, is delayed to a delay value of? / 2, thereby appropriately converting the polarization state to a desired shape. The incident polarization of the remaining incident angle is converted into circular polarized light by the optical axis crossing structure.

Here, converting the incident polarization of the specific incident angle into the desired polarization state can be defined by the following equations.

In general, the polarization state of light can be described in terms of four positive terms. First, the polarization state of incident polarization is expressed by an equation, as shown in Equations 1 and 2 below.

이다.here,

to be.

Using these equations 1 and 2 as they are, the Stokes parameters of incident polarization can be expressed as follows.

Representative polarization states of incident polarization based on Equation-3 to Equation-6 are shown in Table-1 below.

TABLE-1

That is, as shown in Table-1, the polarization state of the incident polarization can be expressed by four terms (stock vectors). Here, the polarization state of the incident polarization may be formed at various angles and states, which may be obtained as Stokes vector values by the above-described equations 3 to 4.

Accordingly, if the polarization state of the incident incident polarization is to be converted, the Stokes vector of the incident incident polarization may be converted into a Stokes vector corresponding to the polarization state of the desired emission light.

Such Stokes vectors have properties that can be applied to both polarized light and partial polarized light. Using this Stokes vector and Muller matrix, the optical axis angles (θ) of the retardation plates 11b, 12b, and 13b are The polarization state of the incident polarization emitted according to the correlation of the phase delay value β can be expressed by Equation-7 and Equation-8 below.

First, the transfer function of the birefringence muller matrix is shown in Equation-7.

Assuming that the delay plates 11b, 12b, 13b are provided in three pieces, for example, as shown in Figs. 3 and 4 by using the transfer function of Equation-7, the optical axes of the respective delay plates 11b, 12b, 13b. The characteristics of the angles θ ₁ , θ ₂ , θ ₃ and the phase delay values β ₁ , β ₂ , β ₃ , can be calculated by the following Equation-8.

Here, Si is a stock vector corresponding to the polarization state of the incident light,

S ₀ is a stock vector corresponding to the polarization state of the emitted light.

That is, as shown in FIG. 4, in order to obtain the polarization state S ₀ of the output light converted for the incident light polarization state Si of any one type, the optical axis angles of the respective retardation plates 11b, 12b, 13b ( By changing θ ₁ , θ ₂ , θ ₃ ) and phase delay values (β ₁ , β ₂ , β ₃ ,) into Equation-8, the desired polarization state S _{0 of the} emitted light can be obtained.

Here, the addition of the transfer function in the above Equation-8, of course, it is possible to manufacture a phase delay layer (10b) provided with three or more delay plates.

Based on these configurations, theories and equations, various broadband phase delay layers can be fabricated, and representative examples are described below.

<Representative example>

The phase retardation layer 10c of the present example has a specific incident polarization among the incident polarizations as the center wavelength of 550 nm in order to achieve a wide bandwidth. The phase retardation layer is formed by using five delay plates 11c, 12c, 13c, 14c, and 15c. Form 10c.

The phase delay values of the respective retardation plates 11c, 12c, 13c, 14c, and 15c are fixed at 137.5 nm, and the optical axis angles θ ₁ , θ ₂ , θ of the retardation plates 11c, 12c, 13c, 14c, and 15c are fixed. ₃ , θ ₄ , θ ₅ ) to select θ ₁ = 15 °, θ ₂ = 15 °, θ ₃ = 75 ° to convert specific incident polarization to circular polarization, θ ₄ = 135 °, θ ₅ = 180 ° The converted circularly polarized light was selected into linearly polarized light. In addition, the incident polarization of the remaining wavelengths was converted into one-way circularly polarized light by the optical axis angle intersection structure of the retardation plates 11c, 12c, 13c, 14c, and 15c.

The ellipticity of each wavelength is shown in Figures 1 and 2. At this time, when the ellipticity is 0.2 or less, it means that the polarization is almost linear.

Here, Figure 1 shows the ellipticity according to the wavelength when incident at the correct angle of incidence, and Figure-2 shows the ellipticity according to the wavelength generated when the incident angle is shifted. As can be seen in Fig. 2, when the incident light differs by more than 10 °, most of the light is emitted as elliptical polarization in one direction by forming an elliptic ratio of 0.2 or more.

On the other hand, the cholesteric liquid crystal layer (20c), as in the first embodiment described above by arranging the molecular arrangement in one direction helical, the linearly polarized light transmitted from the phase delay layer (10c) is transmitted, the circularly polarized light in one direction is It is provided with a reflecting structure. Here, the molecular arrangement direction of the cholesteric liquid crystal layer 20c is selectively set in the manufacturing step to correspond to the phase delay layer 10c.

By such a configuration, the reflective polarizing film 1c according to the present exemplary embodiment converts a specific polarized light out of broadband incident polarization into a linear polarized light that can pass through the polarizer of the liquid crystal assembly, and converts the remaining polarized light into an ellipse and / or a circle in one direction. It is converted to polarized light and emitted.

The linearly polarized light of the polarized light converted by the phase delay layer 10c is transmitted through the cholesteric liquid crystal layer 20c, and the circularly polarized light in one direction is reflected by the cholesteric liquid crystal layer 20c.

In particular, in the reflective polarizing film 1c according to the present embodiment, any one of the plurality of retardation plates 11c, 12c, 13c, 14c, and 15c is bonded to each other according to the optical axis angle in the phase delay layer 10c. When the retardation plates 11c, 12c, 13c, 14c, and 15c are adhered to the other retardation plates (one of 11c, 12c, 13c, 14c, and 15c) at the wrong optical axis angle, the other retardation plates 11c, 12c, and 13c are attached. Can be corrected when adhering one of .14c, 15c).

On the other hand, Figure 7 is a simplified cross-sectional view of the reflective polarizing film according to a third embodiment of the present invention. The reflective polarizing film 1d according to the present embodiment has the configuration of the phase delay layer 10d which is almost the same as that of the first and second embodiments described above, and the light is emitted from the surface of the emission side of the cholesteric liquid crystal layer 20d. The refractive pattern for condensing and refracting the light in a substantially vertical direction is formed.

The refraction pattern is formed of a prism pattern having a triangular cross section during cross-sectional projection, and the prism peak angle θp at this time is preferably formed to have a prism peak angle of 70 ° to 110 °. This refractive pattern improves the luminance of the emitted light emitted from the reflective polarizing film 1d.

Here, the prism peak of the refractive pattern may be variously changed according to the condition. In addition, the pattern size and the pattern arrangement of the refractive pattern may be formed regularly or irregularly.

8 is a simplified cross-sectional view of the reflective polarizing film according to the fourth embodiment of the present invention. As shown in this figure, the reflective polarization film 1e according to the present embodiment includes a first phase delay layer 10e and a first phase delay layer 10e for converting a specific incident polarization of the incident polarization into circular polarization. Cholesteric liquid crystal layer 20e and cholesteric liquid crystal layer 20e which pass circularly polarized light in one rotational direction and reflect circularly polarized light in the other rotational direction to the incident side among the circularly polarized light incident on the output side of The second phase retardation layer 30e is laminated on the output side and converts circularly polarized light in one rotational direction passing through the cholesteric liquid crystal layer 20e into linearly polarized light in a specific direction.

Here, the first phase delay layer 10e is manufactured to convert a specific incident polarization into circular polarization in a desired rotational direction using the same method as the phase delay layer 10b of the second embodiment described above. In addition, the second phase delay layer 30e is also manufactured to convert circularly polarized light in one rotational direction into a desired linearly polarized light using the same method as the phase delay layer 10b of the second embodiment.

In addition, the cholesteric liquid crystal layer 20e adjusts the molecular arrangement appropriately so that the circularly polarized light in one rotational direction passes through the circularly polarized light emitted from the first phase delay layer 10e and reflects the circularly polarized light in the other rotational direction. Is produced. At this time, the circularly polarized light in the other rotational direction means any ellipse or circularly polarized light that is not converted to a desired direction in the first phase delay layer 10e.

With this configuration, the reflective polarizing film 1e according to the present embodiment first converts a specific incident polarization of the incident polarization in the first phase delay layer 10e into circular polarization in one rotation direction, and converts the remaining incident polarization. It is converted into an ellipse or circularly polarized light in the other rotational direction and emitted to the cholesteric liquid crystal layer 20e.

Circularly polarized light in one rotational direction incident to the cholesteric liquid crystal layer 20e passes through the cholesteric liquid crystal layer 20e as it is and enters the second phase delay layer 30e, and an ellipse or circularly polarized light in the other rotational direction is It is reflected to the incident side.

The circularly polarized light in one rotational direction incident on the second phase delay layer 30e is converted into a desired linearly polarized light in the second phase delay layer 30e and is emitted.

In the reflective polarizing film 1e according to the present embodiment, the cholesteric liquid crystal layer 20e is disposed between the first phase delay layer 10e and the second phase delay layer 30e. ) Can be protected. In addition, as the specific polarization of the incident polarization passes through the first phase delay layer 10e, the cholesteric liquid crystal layer 20e, and the second phase delay layer 30e, the change to the accurate linearly polarized light and the reflection action of the remaining polarizations are It can be efficiently made to improve the performance of the reflective polarizing film (1e) as much as possible.

On the other hand, Figure 9 is a simplified block diagram of a display device having a reflective polarizing film according to the present invention. As shown in the figure, the display device 50 having the reflective polarizing film according to the present invention is a reflective polarizing film according to the first to fourth embodiments described above between the optical cavity 60 and the liquid crystal assembly 70 Any one of (A) is arrange | positioned.

The light generated from the optical cavity 60 passes through the reflective polarizing film A, and as described above, the specific polarized light is converted into linearly polarized light through which the polarizer 71 of the liquid crystal assembly 70 can pass, thereby converting the liquid crystal assembly. And the remaining polarized light is converted into circularly polarized light and reflected from the cholesteric liquid crystal layer (a) to the optical cavity 60.

Passed through the polarizer 71 of the linearly polarized liquid crystal assembly 70 to the liquid crystal assembly 70 is used as the light for the image display, the remaining reflected polarization in the diffuse reflection surface 61 of the optical cavity 60 The polarization direction of the light is reflected in a randomized state and then transmitted to the reflective polarizing film (A).

As a result, the remaining polarized light is converted into linearly polarized light in the reflective polarizing film A and transferred to the liquid crystal assembly 70.

As a result, most of the light generated in the optical cavity 60 is supplied to the liquid crystal assembly 70, thereby minimizing the loss of light, and thus, it is possible to reduce power waste for additional generation of light.

Here, the reflective polarizing film A may be installed as a separate optical component between the optical cavity 60 and the liquid crystal assembly 70, as shown in FIG. 9, and integrally formed on the incident side lower surface of the liquid crystal assembly 70. It may be installed. In addition, the reflective polarizing film (A) may be integrally installed on the output side upper surface of the optical cavity 60.

10 and 11 are schematic diagrams of a display apparatus according to another exemplary embodiment of the present invention. As shown in these drawings, the display device 50 ′ according to the present embodiment is substantially the same as the configuration of the display device 50 of FIG. 9 described above, and has a light diffusion layer provided under the reflective polarizing film A. 80) more.

The light diffusion layer 80 may be provided as a light diffusion film containing a plurality of diffusion particles 81, as shown in Figure 10, wherein the diffusion particles 81 are made of acrylic particles, styrene particles, silicon particles, Transparent solid particles may be used, or may be provided with a plurality of air particles having a bubble shape instead of solid particles.

Alternatively, the light diffusion layer 80 may include a plurality of diffusion patterns 91 having an optical cross section of a partial arc and a plurality of triangular optical cross sections formed along a pattern surface of the diffusion pattern 91 as shown in FIG. 11. It may be formed in a structure having a refractive pattern 93. The light diffusion layer 90 has a refractive pattern 93 formed along the diffusion pattern 91 to induce the refractive diffusion of light.

By forming the light diffusing layer 80 or 90 under the reflective polarizing film A as described above, the light incident on the reflective polarizing film A is diffused, thereby realizing high brightness at the exit side, and the reflective polarizing film A ) Foreign objects such as scratches or dust and stains that may be contained inside can be prevented from being visually transmitted to the viewer.

Here, the light diffusing layer 80 or 90 may be integrally formed at the bottom of the reflective polarizing film A, or may be provided as a separate optical component (diffusion film) according to the condition and disposed below the reflective polarizing film A. have.

As described above, the reflective polarizing film and the display device having the same according to the present invention convert the specific polarization and the remaining polarization of the incident polarization from the phase delay layer of the reflective polarization film into linearly polarized and circularly polarized light, respectively, and then the cholesteric liquid crystal layer. Since the linearly polarized light is transmitted and the circularly polarized light is reflected toward the incidence side, the incident polarization can be effectively separated with the optical layers stacked in a significantly smaller number.

Thereby, the reflective polarizing film can be produced by a relatively simple manufacturing process, and the light loss can be reduced.

In addition, by forming an optical pattern in the cholesteric liquid crystal layer, the luminance can be sufficiently improved without adding a separate prism film. Thereby, manufacturing cost can be reduced by reducing the number of optical components.

As described above, according to the present invention, there is provided a reflective polarizing film and a display device having the same, which can be easily manufactured and reduce optical components, while improving luminance and minimizing light loss.

Claims (12)

In a reflective polarizing film that transmits linearly polarized light in one direction among incident polarizations incident on different wavelength bands and reflects the remaining polarizations, At least one phase delay layer for converting and outputting a specific polarization of the incident polarization into the linearly polarized light and converting the remaining polarization into an ellipse or circular polarization; And a cholesteric liquid crystal layer laminated on the exit side of the phase delay layer to reflect the ellipse or circularly polarized light in the incident direction. In a reflective polarizing film that transmits linearly polarized light in one direction among incident polarizations incident on different wavelength bands and reflects the remaining polarizations, A first phase delay layer disposed on the incidence side of the incident polarization and converting the incident polarization into the ellipse or circular polarization; A cholesteric liquid crystal layer laminated on the exit side of the first phase delay layer to pass polarization in one rotation direction of the ellipse or circular polarization and reflect polarization in the other rotation direction to the incidence side; And a second phase retardation layer laminated on the exit side of the cholesteric liquid crystal layer and converting the polarization in one rotational direction passing through the cholesteric liquid crystal layer into linearly polarized light in the specific direction. film. The method according to claim 1 or 2, The phase delay layer is formed by stacking a plurality of retardation plates made of an organic material thin film having birefringence so as to cross the optical axis, and retards incident light in a wavelength range of 400 nm to 700 nm to a retardation value of λ / 2. Reflective polarizing film. The method of claim 3, The phase delay layer is a reflective polarizing film, characterized in that the at least two retardation plates having mutually different retardation values are laminated so as to cross the optical axis. The method of claim 3, The phase delay layer is a reflective polarizing film, characterized in that the lamination is formed so that at least three retardation plates having the same retardation value mutually optical axis cross. The method of claim 3, And at least one of the incidence side surface and the outgoing side surface of the cholesteric liquid crystal layer is formed with a refractive pattern for condensing and refracting light in a substantially vertical direction. The method of claim 6, The refractive pattern is a reflective polarizing film, characterized in that the prism shape having a triangular cross-section in the projection projection. The method of claim 7, wherein The refractive pattern is a reflective polarizing film, characterized in that having a prism peak angle of 70 ° to 110 °. An optical cavity that emits light and has a diffuse reflecting surface at a lower portion thereof, a liquid crystal assembly that displays an image by using linearly polarized light in one direction among light transmitted from the optical cavity, and is disposed between the optical cavity and the liquid crystal assembly In the display device having a reflective polarizing film which transmits the linearly polarized light in any one direction of the incident polarization transmitted from the optical cavity and reflects the remaining polarization, The reflective polarizing film is a display device, characterized in that the reflective polarizing film of claim 1 or 2. The method of claim 9, And a light diffusing layer provided between the reflective polarizing film and the optical cavity. The method of claim 10, The light diffusing layer is a display device, characterized in that the diffusion particles are diffused therein. The method of claim 10, And the light diffusing layer comprises a plurality of diffusion patterns having an optical cross section on a partial arc and a plurality of refractive patterns having a triangular optical cross section formed along a pattern surface of the diffusion pattern.

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