KR20180007454A - Optical member and liquid crystal display including the same - Google Patents

Abstract

Provided is an optical member having an improved color reproduction rate. The optical member comprises: a narrowband reflection polarizing part; and a broadband reflection polarizing part laminated on the narrowband reflection polarizing part, wherein the width of a reflection polarizing wavelength band of the narrowband reflection polarizing part is smaller than the width of the reflection polarizing wavelength band of the broadband reflection polarizing part.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical member and a liquid crystal display including the optical member.

The present invention relates to an optical member and a liquid crystal display including the optical member.

A liquid crystal display (LCD) is a device for displaying an image by injecting liquid crystal between two glass plates and applying power to the upper and lower glass plate electrodes to change the arrangement of liquid crystal molecules in each pixel. Unlike a cathode ray tube (CRT), a plasma display panel (PDP) or the like, a display using a liquid crystal display device is not usable in a place where there is no light because the display itself is non-luminous. In order to compensate for these drawbacks, a backlight assembly that is uniformly irradiated on the information display surface is mounted for the purpose of enabling use in a dark place.

A typical liquid crystal display device emits light in a wavelength band of visible light incident from a backlight using an LED light source through various color filters of the panel to transmit only light of different wavelength band for each pixel, thereby realizing various colors displayed on the screen. However, the wavelength of light to be filtered by the color filter is wide and color reproducibility is poor. For example, in the case of an organic light emitting diode (OLED) as a self-luminous element, red, green, and blue colors can be expressed with a narrow range of wavelengths to express excellent saturation. However, in the case of the color filter, since the transmitted wavelength is relatively wide, even in the case of expressing pure red, a considerable amount of light in the neighboring green wavelength band is also leaked, so pure red is not expressed well. Therefore, it is difficult for an ordinary liquid crystal display device using a color filter to accurately express the color of objects. In order to improve the color reproducibility, a structure in which a separate wavelength converting member using pigments or dyes is additionally disposed is considered. However, such a structure may cause a remarkable decrease in luminance compared to the efficiency of improving color reproducibility.

 An object of the present invention is to provide an optical member capable of remarkably improving color reproducibility while minimizing luminance degradation, that is, maximizing the efficiency of improving color reproducibility.

Another object of the present invention is to provide a liquid crystal display device with improved color reproducibility while minimizing luminance degradation.

The problems of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided an optical member including a narrowband reflective polarizer and a broadband reflective polarizer stacked on the narrowband reflective polarizer, The width of the band is smaller than the width of the reflection polarized wave band of the broadband reflective polarizer.

According to another aspect of the present invention, there is provided a liquid crystal display device including the optical member, and a liquid crystal display panel disposed on the optical member.

The details of other embodiments are included in the detailed description and drawings.

According to the optical member and the liquid crystal display device according to the embodiments of the present invention, by selectively reducing the light of a specific wavelength band, the color reproduction rate can be increased while minimizing the decrease in luminance.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the specification.

1 is a schematic view of a liquid crystal display device according to an embodiment of the present invention.
2 is a light spectrum of light emitted in a white mode of a general liquid crystal display device.
3 is a cross-sectional view of an optical member according to an embodiment of the present invention.
4 is a graph showing the optical spectrum of the cholesteric liquid crystal layer.
5 is a graph showing an optical spectrum of a broadband reflective polarizing layer according to an embodiment of the present invention.
6 is a sectional view of a narrow band liquid crystal film of an optical member according to another embodiment of the present invention.
7 is a cross-sectional view of an optical member according to another embodiment of the present invention.
8 is a cross-sectional view of an optical member according to another embodiment of the present invention.
9 is a cross-sectional view of an optical member according to another embodiment of the present invention.
10 is a schematic diagram of a backlight unit according to an embodiment of the present invention.
11 is a graph showing the optical spectrum of light emitted when the backlight unit according to Comparative Example and Production Example 31 is mounted on a liquid crystal display panel and driven in a white mode.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

It is to be understood that elements or layers are referred to as being "on " other elements or layers, including both intervening layers or other elements directly on or in between. On the other hand, a device being referred to as "directly on" refers to not intervening another device or layer in the middle. Like reference numerals refer to like elements throughout the specification. "And / or" include each and any combination of one or more of the mentioned items.

Although the first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical scope of the present invention.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms " comprises "and / or" comprising "used in the specification do not exclude the presence or addition of one or more other elements in addition to the stated element.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" And can be used to easily describe a correlation between an element and other elements. Spatially relative terms should be understood in terms of the directions shown in the drawings, including the different directions of components at the time of use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element . Thus, the exemplary term "below" can include both downward and upward directions. The components can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

As used herein, the terms "to sheet "," to film ", "to plate ", and the like may be used interchangeably. In addition, the optical member, which is a term in this specification, can be used to mean an optical sheet, an optical film, an optical plate, an optical film package and the like. In the present specification, the term " transmission axis "means a transmission axis.

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

1 is a schematic view of a liquid crystal display device according to an embodiment of the present invention.

1, a liquid crystal display device 50 according to an exemplary embodiment of the present invention includes a light source 30, an optical member 10 disposed on the light source 30, a liquid crystal display panel 20 ). 1 illustrates a case where the liquid crystal display device 50 includes a direct-type backlight unit, but may also include an edge-type backlight unit with the light source on the side.

The light source 30 serves to provide light to the optical member 10. The light source 30 may be a light emitting diode (LED), but the present invention is not limited thereto, and a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), an external electro fluorescent lamp (EEFL) .

The light source 30 may be a white light source, but a light source that emits light of a specific wavelength such as blue or ultraviolet light may be used. For example, when a blue LED is used as the light source 30, the light conversion material can be converted to white light by being disposed on the optical path. The photo-conversion material may be arranged immediately adjacent to the light source 30 or on the side of the optical member 10 or on the inside or outside of the liquid crystal display panel 20. [ In the following embodiments, the blue LED is used as the light source 30, and the light conversion material is disposed on the optical member 10, but the present invention is not limited thereto.

The optical member 10 includes a light wavelength conversion member 16 and a reflective polarizing member 15.

The light wavelength converting member 16 may be disposed between the light source 30 and the reflective polarizing member 15. [ The light wavelength converting member 16 receives blue light from the light source 30 and converts the blue light into white light.

The light wavelength conversion member 16 includes a wavelength conversion material. The wavelength converting material may be a quantum dot. The quantum dot may be a spherical semiconductor nanomaterial having a size of several nanometers to several hundreds of nanometers, and may include a core composed of a material having a small band gap and a shell arranged to surround the core. Quantum dots have discontinuous band gap energies unlike bulk materials due to the quantum confinement effect. When a quantum dot absorbs light, it emits light of a wavelength different from the incident light as the energy level is lowered inside the quantum dot. The details of the light wavelength converting member 16 will be described later.

The reflective polarizing member 15 has a reflection polarizing characteristic, and can transmit specific polarized light and reflect other specific polarized light. Light that has passed through the light source 30 and / or the light wavelength conversion member 16 is provided to the reflective polarizing member 15, and is converted into light of a specific polarized light. That is, the optical member 10 can convert non-polarized light into specific polarized light and emit it. As described above, the light having the specific polarized light emitted by the optical member 10 can be effectively utilized for display and the like. For example, the liquid crystal display panel 20 displays an image by controlling the transmittance of light. The liquid crystal display panel 20 typically controls the transmittance using polarized light. The liquid crystal display panel includes polarizing elements such as polarizing plates 21 and 22, a wire grid, etc. in order to use polarized light. The incident-side polarizing plate 21 blocks the unpolarized light in a specific direction before the light passes through the liquid crystal layer, thereby allowing the polarized light to be incident on the liquid crystal layer. Therefore, the light polarized in a direction different from that of the incidence-side polarizer 21 of the liquid crystal display panel 20 is blocked and can not be used in the liquid crystal display panel 20, resulting in a loss in luminance.

In the present embodiment, the light reflected by the reflective polarizing member 15 travels in the direction opposite to the emitting direction of the optical member 10. The reflected light is refracted and reflected by the optical recycling structure inside the backlight assembly, and can be reentered upward again. The phase of the light is changed in the recycling process, and the polarized light when the light is reflected is not maintained, and the various polarized lights are converted into the mixed unpolarized state. Therefore, the re-entered light passes through the reflective polarizing member 15 again and is transmitted or reflected according to the polarized state. This recycling process can be repeated.

As a result of the recycling process, the amount of light having a specific polarized light emitted through the optical member 10 is amplified. The transmissive axis of the broadband reflective polarizing section 13 of the reflective polarizing member 15 is aligned in the same direction as the transmissive axis of the incident-side polarizing plate 21 of the liquid crystal display panel 20, The amount of light blocked by the light emitting elements 21 is reduced, and the overall luminance efficiency can be increased.

The reflective polarizing member 15 includes a narrowband reflective polarizing section 11 and a broadband reflective polarizing section 13 laminated (for example, on top) on the narrowband reflective polarizing section 11. The narrow-band reflection polarizing section 11 and the wide-band reflective polarizing section 13 are respectively reflected and polarized with respect to light of at least some wavelengths.

The narrow-band reflection polarizing section 11 and the wide-band reflective polarizing section 13 may have different types of polarized light to be reflected and polarized. For example, the broadband reflective polarizer 13 is a linearly polarized reflection polarizer that reflects linearly polarized light. Specifically, the broadband reflection polarizing section 13 can transmit either the p-wave or the s-wave in the reflection wavelength band and reflect the other. On the other hand, the narrow-band reflection polarizing section 11 is a circularly polarization-type reflection polarizing section that reflects and circularly polarizes circularly polarized light. Specifically, the narrowband reflection polarizing section 11 transmits either the left circularly polarized light or the right circularly polarized light in the reflection polarized wavelength band and reflects the other. However, the present invention is not limited to this, and the narrow-band reflection polarizing section 11 and the wide-band reflective polarizing section 13 may reflectively polarize the same kind of polarized light.

The narrow-band reflection polarizing section 11 and the wide-band reflective polarizing section 13 may have different wavelength bands as well as types of wavelengths to be reflected and polarized.

For example, the broadband reflective polarizer 13 has a reflective polarizing function for light in most visible wavelength bands. For example, the broadband reflective polarizing section 13 can reflect and polarize light in the entire visible light wavelength band ranging from 380 nm to 780 nm.

On the other hand, the narrowband reflection polarizing section 11 has a reflection polarizing function only for a specific wavelength band that is significantly narrower than that of the broadband reflection polarizing section 13. That is, the width of the reflection polarized light wavelength band of the narrowband reflection polarized light section 11 is smaller than the width of the reflection polarized light wavelength band of the wideband reflection polarized light section 13.

More specifically, the narrowband reflection polarizing section 11 transmits light other than the wavelength band having the reflective polarizing function as it is. The wavelength range of light for which the narrowband reflection polarizing section 11 performs the reflection polarizing function may be included in the wavelength range of the light for which the wideband reflection polarizing section 13 is reflective polarized. For example, the narrowband reflection polarizing section 11 may have a reflection polarizing function with respect to light in the vicinity of 580 nm. Herein, the half width of the reflection wavelength band of light may be 70 nm or less.

When the narrowband reflection polarizing section 11 has a circularly polarized reflection polarizing function with respect to light in the vicinity of 580 nm and its half width is 70 nm, the wavelength range in which the narrow reflection polarizing section 11 effectively reflects the reflected polarized light is 545 nm To 615 nm. The narrowband reflection polarizing section 11 substantially transmits light in a wavelength range other than 545 nm to 615 nm as it is.

For convenience of explanation, the wavelength range in which the reflection polarized light is not formed in the narrowband reflection polarized portion 11 and the reflection polarized light is made in the wideband reflection polarized portion 13 is referred to as a first wavelength range, and the narrowband reflection polarized portion 11 And the broadband reflection polarizing section 13 are referred to as a second wavelength range.

The light that is provided from the light source 30 to the reflective polarizing member 15 through the light or light source 30 and through the light wavelength conversion member 16 to the reflective polarizing member 15 emits light in the first wavelength range, It can include all the light in the wavelength range.

The light of the first wavelength range provided to the reflective polarizing member 15 passes through the narrow-angle retroreflective polarizer 11 regardless of the polarization. The light having passed through the narrow retroreflective polarizing section 11 is incident on the broadband reflective polarizing section 13 and the linearly polarized light coinciding with the transmission axis of the broadband reflective polarizing section 13 is transmitted and transmitted through the broadband reflective polarizing section 13 Linear light perpendicular to the axis is reflected. The reflected linearly polarized light can be recycled.

On the other hand, light in the second wavelength range provided to the reflective polarizing member 15 is subjected to reflection polarized light in the narrow-reverse-polarized polarizing section 11. For example, the narrow-reverse-reflection polarization section 11 can transmit left-handed circularly polarized light and can reflect right-handed circularly polarized light. The transmitted left-handed circularly polarized light again travels to the wide-band reflective polarizing section 13, and the wide-band reflective polarizing section 13 dissolves it into a linearly polarized light component and transmits and reflects the left-circularly polarized light. The reflected right-handed circularly polarized light can be recycled.

As described above, the light in the first wavelength range is mostly transmitted through the narrow-band retroreflective polarizer 11 and enters the broadband reflective polarizer 13. However, the light in the second wavelength range is partially narrow- And transmits the light. Of course, although the light reflected by the narrow-reverse-reflection polarization section 11 is recycled, the amount thereof is reduced as compared with that transmitted through the entirety. Therefore, when the narrow reverse-reflection polarizing section 11 is used, the amount of light in the second wavelength range is relatively smaller than the amount of light in the first wavelength range, as compared with the case in which the narrow-reverse-reflection polarizing section 11 is not used.

By appropriately using such a narrow-band reverse-reflection polarization section 11, the amount of light in an undesired wavelength band can be reduced.

2 is a light spectrum of light emitted in a white mode of a general liquid crystal display device. FIG. 2 exemplarily shows the light spectrum of light emitted from the liquid crystal display device to illustrate the color reproduction rate of the screen of the liquid crystal display device. However, since the light emitted from the liquid crystal display device is provided from the backlight, It will be understood that the light emitted from the light source or the blue light source and converted by the wavelength conversion film will also have a peak and a peak at a wavelength substantially the same as the spectrum of Fig.

Referring to FIGS. 1 and 2, the optical spectrum shows the first high peak peak Ph1 near the blue wavelength of about 450 nm, the second high peak peak Ph2 near the green wavelength of about 530 nm, the red peak wavelength of about 630 nm (Ph3) at the second peak point (Ph3). In addition, it has a first low peak P1 at about 480 nm and a second low peak P2 at around 580 nm.

The first to third high peak peaks (Ph1, Ph2, Ph3) represent blue, green, and red hues, respectively, and the luminance increases as their values increase. On the other hand, the vicinity of the first low peak point Pl1 is a period in which an intermediate color of blue and green is expressed, and the interval between the second low peak point Pl2 and the intermediate color of green and red is expressed. However, the color purity decreases.

Therefore, when the second wavelength range, which is reflected and polarized by the narrowband reflection polarizing section 11, is positioned near the first low peak P1 or the second low peak P2, light in the wavelength range is reduced, . However, it is preferable that the second wavelength range does not overlap with the first to third high peak peaks Ph1, Ph2, and Ph3. When the second wavelength range is overlapped with the first to third high peak peaks Ph1, Ph2 and Ph3, not only the luminance is greatly reduced, but also the pure color light located near the peak value decreases together and the color purity can be reduced.

From the above viewpoint, it is preferable that the reflection central wavelength of the narrow-band reflection polarizing section 11 does not overlap with the peak peaks Ph1, Ph2 and Ph3. The wavelength distances between the central wavelengths of the reflected polarized light of the narrowband reflection polarizing section 11 and the peak peaks Ph1, Ph2 and Ph3 adjacent thereto correspond to the peak wavelengths of the reflected polarized light of the narrowband reflective polarizing section 11 and the low peak peaks Pl1, and Pl2).

It is preferable that the section corresponding to the half width (the width of the section where the reflectance is half or more of the maximum reflection value) of the narrowband reflection polarizing section 11 does not overlap with the high peak peaks Ph1, Ph2 and Ph3. On the other hand, the low peak peaks Pl1 and Pl2 may be included in a section corresponding to the half width of the narrowband reflection polarizer.

For example, a narrow-band reflective polarizing section 11 having a half-width of 70 nm or less and a reflective polarized central wavelength of 480 nm and / or a narrow-band reflective polarizing section 11 having a half-width of 70 nm or less and a reflective polarized center wavelength of 580 nm It is possible to improve the color purity while reducing the luminance drop.

More specific details will be described later with reference to Production Examples and Experimental Examples.

Hereinafter, the optical member 10 will be described in more detail.

3 is a cross-sectional view of an optical member according to an embodiment of the present invention. In this embodiment, a case is described in which the optical member includes only the reflective polarizing member without the light wavelength converting member.

3, the optical member 100 includes a narrow band liquid crystal film 110 and a wide band reflective polarizer film 130 stacked on the narrow band liquid crystal film 110. [ The narrow band liquid crystal film 110 corresponds to the narrow band reflection polarizing portion 11 of Fig. 1 and the broad band reflective polarizing film 130 corresponds to the wide band reflective polarizing portion 13 of Fig. In the figure, the main travel path of light through the optical member 100 is from the bottom to the top.

The narrow band liquid crystal film 110 includes a substrate 112 and a cholesteric liquid crystal layer 111 formed on the substrate 112. 3, the substrate 112 is disposed on the outermost side where light is incident, and the cholesteric liquid crystal layer 111 is disposed on the emission side. However, the present invention is not limited thereto, and the substrate 112, The position of the layer 111 may be changed with each other or may be incident on the cholesteric liquid crystal layer 111 after light is incident on the functional layer such as the antireflection layer. In addition, the substrate 112 may be omitted as the case may be.

The cholesteric liquid crystal layer 111 is a layer that transmits either the left-handed circularly polarized light or the right-handed circularly polarized light with respect to light of a specific wavelength band and reflects the other. The cholesteric liquid crystal layer 111 includes a cholesteric liquid crystal. The wavelength band that the cholesteric liquid crystal transmits and reflects can be controlled by the pitch of the cholesteric liquid crystals.

For example, the cholesteric liquid crystal layer 111 may include a cholesteric liquid crystal having a pitch with a minimum transmittance in a wavelength band of 470 nm to 490 nm.

4 is a graph showing the optical spectrum of the cholesteric liquid crystal layer. Referring to FIG. 4, the optical spectrum of the cholesteric liquid crystal layer 111 has one valley in the wavelength band near about 480 nm. The low point of the bone is located at about 480 nm, the light transmittance may be in the range of 40 to 60%, and preferably in the vicinity of 50%. The wavelength band outside the bone may have a light transmittance of 80% or more, and preferably 90% or more.

The narrower the width of the reflection polarization band of the cholesteric liquid crystal layer 111, the more favorable the brightness. The width of the reflection polarized light band is related to the half width. The half width is defined as the distance between two X-coordinates intersecting a straight line passing between the maximum value and minimum value in the downward convex graph. Therefore, the half width of the optical spectrum can be defined as the width between two wavelengths corresponding to the intermediate transmittance which is an intermediate value between the maximum transmittance and the minimum transmittance in the optical spectrum. The half width of the optical spectrum of the cholesteric liquid crystal layer 111 to have the above narrow reflection polarized light band may be 70 nm or less, preferably 60 nm or less, more preferably 30 nm or less, still more preferably 20 nm or less.

For example, if the cholesteric liquid crystal layer 111 has a minimum transmittance at 480 nm and a half width of 70 nm, it exhibits an effective reflection polarizing function in a wavelength band of 445 nm to 515 nm. In this case, the cholesteric liquid crystal layer 111 transmits less wavelength band of 445 nm to 515 nm than light of other wavelength bands. Therefore, the color reproduction ratio can be improved by reducing the light of 445 nm to 515 nm in the light spectrum transmitted through the optical member 100.

In order for the cholesteric liquid crystal layer 111 to have a narrower half width, it is advantageous that the cholesteric liquid crystal has a small refractive index anisotropy. For example, when a cholesteric liquid crystal having a refractive index anisotropy of 0.16 or less is used, the half width can be reduced to 70 nm or less, and when the refractive index anisotropy of the liquid crystal is 0.12 or less, the half width can be further reduced to 30 nm or less, When the refractive index anisotropy is 0.10 or less, the half width can be further reduced to 20 nm or less, and a narrow reflective polarized light band can be realized.

In the present embodiment, the case where the cholesteric liquid crystal layer 111 includes a cholesteric liquid crystal having a pitch having a minimum transmittance in a wavelength band from 470 nm to 490 nm is exemplified. However, the present invention is not limited thereto. For example, a wavelength of 570 nm to 590 nm And a cholesteric liquid crystal having a pitch with a minimum transmittance in another wavelength band such as a band.

Referring again to FIG. 3, the optical member 10 may further include a retardation layer 120. The phase difference layer 120 is disposed on the cholesteric liquid crystal layer 111 to change the phase of the light emitted through the cholesteric liquid crystal layer 111. The phase change value of the retardation layer 120 is preferably a value capable of converting circularly polarized light selectively transmitted by the cholesteric liquid crystal layer 111 into linearly polarized light. For example, the retardation layer 120 may have a phase delay value of? / 4. The polarization direction of the linearly polarized light converted by the retardation layer 120 may be different from the transmission axis of the upper broad band reflective polarizing film 130. [ For example, the polarization direction of the linearly polarized light converted by the retardation layer 120 may be perpendicular to the transmission axis of the broadband reflective polarizing film 130, have an inclination angle of 30 to 80, or have an inclination angle of about 45 have.

The cholesteric liquid crystal layer 111 transmits only the specific circularly polarized light for the light in the reflection wavelength band. On the other hand, light other than the reflection wavelength band is transmitted irrespective of the circular polarization. Therefore, the light in the reflection wavelength band of the light passing through the retardation layer 120 is converted into linearly polarized light, but the light in the other wavelength band is only converted in the polarization state at the time of emergence, Polarized light. The light passing through the retardation layer 120 includes the linearly polarized light of the reflection wavelength band more than the linearly polarized light of the other wavelength band. Therefore, if the transmission axis of the upper broadband reflective polarizing film 130 is arranged to be different from the polarizing direction of the linearly polarized light of the reflection wavelength band, for example, vertically, the corresponding light is transmitted through the upper broadband reflective polarizing film 130 Can be effectively reduced or blocked. Therefore, the color reproducibility can be improved.

Although the figure illustrates a case where a film-shaped retardation layer 120 made of uniaxially or biaxially stretched plastic is disposed between the narrow band liquid crystal film 110 and the broadband reflective polarizer film 130, But may be provided in various other forms.

For example, the retardation layer 120 may be formed by coating, applying, or transferring a resin including an A-plate liquid crystal or a C-plate liquid crystal. In this case, the retardation layer 120 may be formed on a separate substrate, but may be formed directly on the narrowband liquid crystal film 110 or the broadband reflective polarizing film 130.

For example, the narrow band liquid crystal film 110 and the retardation layer 120 may be formed by coating a cholesteric liquid crystal layer 111 on one surface of a base material 112 and forming a retardation layer 120 on the other surface of the base material 112 Coating method. Alternatively, the cholesteric liquid crystal layer 111 may be coated with a cholesteric liquid crystal layer 111 on one side of the substrate 112 and the retardation layer 120 may be coated on one side of the cholesteric liquid crystal layer 111. In this case, the substrate 112 will be disposed at the bottom. Conversely, the retardation layer 120 may be coated on one side of the substrate 112 and the cholesteric liquid crystal layer 111 may be coated on one side of the retardation layer 120. In this case, the substrate 112 is disposed so as to face the uppermost portion. In the above examples, an adhesive layer such as a primer layer may be further interposed between the substrate 112, the cholesteric liquid crystal layer 111, and the retardation layer 120.

When the retardation layer 120 is provided as a retardation film made of plastic, the retardation layer 120 itself can serve as a base. In this case, the above-described base material 112 may be omitted, a cholesteric liquid crystal may be coated on the retardation film, or a separate cholesteric liquid crystal film may be formed and laminated. In the same way, the retardation layer 120 may be integrated with the broadband reflective polarizing film 130. [

It will be appreciated by those skilled in the art that various other known methods for forming the retardation layer 120 into one integral film with the cholesteric liquid crystal layer 111 and / or the broadband reflective polarizing film 130 can be applied There will be. The retardation layer 120 may be omitted.

A wide band reflective polarizing film 130 is disposed on the narrow band liquid crystal film 110. The wide band reflective polarizing film 130 is disposed on the light emitting side of the narrow band liquid crystal film 110. The wide band reflective polarizing film 130 may be disposed close to the narrow band liquid crystal film 110. [ The broadband reflective polarizing film 130 may be positioned so as to overlap with the narrow band liquid crystal film 110.

The broad-band reflective polarizing film 130 includes a broad-band reflective polarizing layer 131. The broadband reflective polarizing layer 131 has reflective polarizing properties in a wider wavelength band than the cholesteric liquid crystal layer 111.

The broad-band reflective polarizing layer 131 may be a multilayered reflective polarizing layer or a stretched reflective polarizing layer in which a high refractive index layer and a low refractive index layer are elongated and alternately laminated. The wide band reflective polarizing layer 131 may be a polymer dispersion type having a plurality of second polymers having different refractive indexes in the first polymer layer or a polymer type reflective polarizing layer having fibers instead of the second polymer, And may be a wire grid type reflective polarizing layer having a pattern.

The wide-band reflective polarizing layer 131 is a multilayer reflective polarizing layer in which a high refractive index layer and a low refractive index layer are stretched and laminated alternately. The broadband reflective polarizing layer 131 includes a plurality of alternately stacked first refractive layers (131a) and a second refractive layer (131b). The first refraction layer 131a may be a PEN layer, and the second refraction layer 131b may be a COPEN layer.

The refractive indexes of the first refractive layer 131a and the second refractive layer 131b may be different from each other along the first direction and the refractive index may be the same along the second direction perpendicular to the first direction. Since the refractive indexes of the first refraction layer 131a and the second refraction layer 131b in the second direction are substantially equal to each other, the linearly polarized light oscillating in the second direction transmits the broadband reflective polarizer. On the other hand, since the refractive indices of the first refractive layer 131a and the second refractive layer 131b are different from each other in the first direction, light oscillating in the first direction is transmitted through the first refractive layer 131a and the second refractive layer 131b Lt; / RTI >

The reflection efficiency at the interface between the first refraction layer 131a and the second refraction layer 131b is correlated with the wavelength and the thickness of the first refraction layer 131a and the thickness of the second refraction layer 131b. There is a thickness of each layer having the maximum reflection efficiency for the wavelength. The longer the wavelength, the greater the thickness of each layer exhibiting the maximum reflection efficiency. Therefore, in order to have excellent reflection efficiency in the entire wavelength range of visible light, the broadband reflective polarizer layer 131 is provided with the first refraction layer 131a and the second refraction layer 131b having various thicknesses. For example, the broadband reflective polarizer layer 131 may include a first refraction layer 131a and a second refraction layer 131b having a first thickness and a maximum reflection efficiency at a blue wavelength, The first refraction layer 131a and the second refraction layer 131b having a second thickness larger than the first thickness and the first refraction layer 131a having a third thickness larger than the second thickness having the maximum reflection efficiency at the red wavelength, And a second refractive layer 131b.

Although not shown in the drawing, the broadband reflective polarizing layer 131 may further include a substrate on which a plurality of first refraction layers 131a and a second refraction layer 131b alternately stacked are formed, and further, And a concavo-convex layer formed on the transparent substrate and performing at least one of a light diffusion function, a close-contact prevention function, and a concealment function.

5 is a graph showing an optical spectrum of a broadband reflective polarizing layer according to an embodiment of the present invention. Referring to FIG. 5, the light transmittance of the broadband reflective polarizer layer may be 40 to 60% over the entire visible light wavelength range of 380 nm to 780 nm.

Hereinafter, other embodiments of the present invention will be described.

6 is a sectional view of a narrow band liquid crystal film of an optical member according to another embodiment of the present invention. 6, the narrow band liquid crystal film 110_1 of the optical member 101 according to the present embodiment includes a first cholesteric liquid crystal layer 111a and a second cholesteric liquid crystal layer 111b This is different from the embodiment of Fig.

More specifically, the narrow band liquid crystal film 110_1 includes a first cholesteric liquid crystal layer 111a formed on a base material 112, a second cholesteric liquid crystal layer 111b formed on the first cholesteric liquid crystal layer 111a, Layer 111b.

The first cholesteric liquid crystal layer 111a is substantially the same as the cholesteric liquid crystal layer 111 in Fig. The second cholesteric liquid crystal layer 111b includes a cholesteric liquid crystal having a pitch having a minimum transmittance in a wavelength band different from that of the first cholesteric liquid crystal layer 111a. For example, the first cholesteric liquid crystal layer 111a may include a cholesteric liquid crystal having a pitch with a minimum transmittance in a wavelength band of 470 nm to 490 nm, while the second cholesteric liquid crystal layer 111b may include a And a cholesteric liquid crystal having a pitch with a minimum transmittance in a wavelength band of 590 nm. The half widths of the first cholesteric liquid crystal layer 111a and the second cholesteric liquid crystal layer 111b may be 70 nm or less, preferably 60 nm or less, more preferably 30 nm or less, further preferably 20 nm or less .

Since the cholesteric liquid crystal having the minimum transmittance in the wavelength band of 470 to 490 nm as well as the cholesteric liquid crystal having the minimum transmittance in the wavelength band of 570 to 590 nm are included in this embodiment, To 590 nm can be reduced. Therefore, the color reproduction rate can be further improved.

6, the order of stacking the first cholesteric liquid crystal layer 111a and the second cholesteric liquid crystal layer 111b may be reversed. However, it is preferable that the first cholesteric liquid crystal layer 111a and the second cholesteric liquid crystal layer 111b have relatively small reflection central wavelengths, It is more advantageous in terms of luminance and color reproduction rate to be disposed in the light emitting portion.

Although the first cholesteric liquid crystal layer 111a and the second cholesteric liquid crystal layer 111b are in direct contact with each other in Fig. 6, a bonding layer is interposed therebetween, and the first cholesteric liquid crystal layer 111a and the second cholesteric liquid crystal layer 111b It is possible.

In addition to the substrate 112 on which the first cholesteric liquid crystal layer 111a is formed, it may further include a separate substrate on which the second cholesteric liquid crystal layer 111b is formed. At least one of the first cholesteric liquid crystal layer 111a and the second cholesteric liquid crystal layer 111b may be directly laminated on the broadband reflective polarizing layer 131. [

The first cholesteric liquid crystal layer 111a may be formed on one side of the substrate 112 and the second cholesteric liquid crystal layer 111b may be formed on the other side of the substrate 112. [

3, the cholesteric liquid crystal layer includes a cholesteric liquid crystal having a minimum transmittance in a wavelength band of 470 to 490 nm and a cholesteric liquid crystal layer having a minimum transmittance in a wavelength band of 470 to 490 nm, And a cholesteric liquid crystal having a minimum transmittance in a wavelength band of 590 nm.

7 is a cross-sectional view of an optical member according to another embodiment of the present invention. The embodiment of FIG. 7 illustrates that the narrow band liquid crystal film 110, the retardation layer 120, and the broadband reflective polarizing film 130 can be integrated.

The optical member 102 includes a first bonding layer 151 and a retardation layer 120 disposed between the narrow band liquid crystal film 110 and the retardation layer 120 and the wideband reflective polarizing film 130, And a second bonding layer 152 disposed between the first bonding layer 150 and the second bonding layer 152. The narrow band liquid crystal film 110, the retardation layer 120, and the broadband reflective polarizing film 130 may be integrated by the bonding layers 151 and 152. [ The bonding layers 151 and 152 may be composed of a bonding material layer, for example, an adhesive layer, an adhesive layer, or a resin layer. Examples of the material constituting the adhesive layer include a silicone polymer, a urethane polymer, a silicone-urethane hybrid structure, an SU polymer, an acrylic polymer, an isocyanate polymer, a polyvinyl alcohol polymer, a gelatin polymer, a vinyl polymer, a latex polymer, A high-transparency adhesive containing a high molecular substance classified into < RTI ID = 0.0 > An example of the resin layer is a polymer resin including an ultraviolet curable resin or a thermosetting resin. Specifically, it may be composed of an unsaturated fatty acid ester, an aromatic vinyl compound, an unsaturated fatty acid and a derivative thereof, an unsaturated dibasic acid and a derivative thereof, and a vinylcyanide compound such as methacrylonitrile.

In this embodiment, since the films 110, 120, and 130 are combined, the thin film is formed and the assembly is simplified, and since the spacing between the films 110, 120, and 130 is maintained constant, .

8 is a cross-sectional view of an optical member according to another embodiment of the present invention.

8 illustrates that in the embodiment of FIG. 3, the stacking order of the wide band reflective polarizing film 130 and the narrow band liquid crystal film 110 of the optical member 103 can be reversed. That is, the broadband reflective polarizing film 130 may be disposed at the lower portion of the optical path, and the narrow band liquid crystal film 110 may be disposed at the upper portion thereof. Also in this case, the retardation layer 120 is preferably disposed on the narrow band liquid crystal film 110.

9 is a cross-sectional view of an optical member according to another embodiment of the present invention.

Fig. 9 illustrates a case where, in the embodiment of Fig. 3, the optical member 104 further includes another optical film.

9, the optical member 104 further includes a light wavelength conversion film 160 and a composite optical film 170 as well as a narrow band liquid crystal film 110, a retardation film 120, a broadband reflective polarizing film 130, do. An exemplary arrangement order is a light wavelength conversion film 160, a composite optical film 170, a narrow band liquid crystal film 110, a retardation layer 120, and a broadband reflective polarizing film 130. However, the arrangement order is not limited to this, and the composite optical film 170 may be disposed at the lowermost portion, and the light-wavelength conversion film 160 may be disposed thereon.

The composite optical film 170 is disposed under the narrow band liquid crystal film 110. The composite optical film 170 includes a first prism sheet 171, a second prism sheet 172 and a bonding layer 172 disposed between the first prism sheet 171 and the second prism sheet 172 . The composite optical film 170 functions to increase the brightness by condensing the light.

The first prism sheet 171 includes a first base material 171a and a first prism pattern layer 171b disposed on the first base material 171a. The second prism sheet 172 includes a second base material 172a and a second prism pattern layer 172b disposed on the second base material 172a. The prism pattern of the first prism pattern layer 171b may extend in the third direction and the prism pattern of the second prism pattern layer 172b may extend in the fourth direction. Although the third direction and the fourth direction are the same direction for the sake of convenience, the third direction and the fourth direction may be perpendicular to each other and may have an acute angle of intersection.

The bonding layer 173 is disposed on the lower surface of the second substrate 172a. The peak of the first prismatic layer 171b penetrates and bonds at least partially into the bonding layer 173. An air gap is defined between the first prism pattern layer 171b and the bonding layer.

The above-described composite optical film 170 can be replaced with other various types of optical films. For example, the bonding layer of the composite optical film 170 is omitted, and the first prism sheet and the second prism sheet can be laminated without a bonding layer. In addition, the first prism sheet or the second prism sheet of the composite optical film 170 may be replaced with a microlens or a diffusion sheet. Instead of the composite optical film 170, a single prism sheet, a microlens, a diffusion sheet, or the like may be disposed.

The light wavelength conversion film 160 is disposed under the composite optical film 170. The light wavelength conversion film 160 corresponds to the light wavelength conversion member 16 described in Fig.

The wavelength conversion film 160 is disposed on the first barrier film 161, the quantum dot fluorescent film 163 including the quantum dots QD disposed on the first barrier film 161 and the quantum dot fluorescent film 163 The second barrier film 162 may include a first barrier film 162 and a second barrier film 162. [ The quantum dot fluorescent material film 163 is sandwiched between the first barrier film 161 and the second barrier film 162.

The quantum dots QD may comprise a core and at least one shell surrounding the core.

The core may be made of materials such as Group II-VI, Group III-V, and the like. For example, the core may be selected from the group consisting of CdS, CdSe, CdTe, ZnS, ZnTe, HgS, HgSe, HgTe, PbS, PbTe, AlN, AlP, AlAs, GaN, GaP, GaAs, InN, InP, InAs, InSb, Or a mixture thereof, or a mixture thereof.

A shell is a semiconductor quantum dot which forms a coating layer on the surface of a core semiconductor by bonding with the core semiconductor quantum dots. The core / shell structure has a higher luminous efficiency than the single core structure due to the core / shell structure. Nanoparticles can be obtained. The shell has a band gap larger than that of the core semiconductor and functions as a passivation layer for protecting the core semiconductor from the outside. As such a shell, a II-VI group semiconductor having a high bandgap is used. For example, ZnS, CdS or ZnSe can be preferably used. In the combination of the core / shell structure using this, when the core is composed of CdSe or CdS, the shell can use ZnS, and when the core is CdSe, CdS or ZnSe is used as the shell, Various combinations can be used without limitation.

In some embodiments, there may be a plurality of shells surrounding the core. For example, the quantum dot may include a core, a first shell surrounding the core, and a second shell surrounding the first shell.

The first shell may be a semiconductor quantum dot that forms a coating layer on the surface of the core semiconductor in combination with the core semiconductor quantum dots as described above.

The second shell surrounds the first shell, and can act to block moisture and moisture. The second shell may comprise a single layer or multiple layers of inorganic layers. The inorganic material in the inorganic coating layer may include an inorganic oxide such as silica, alumina, titania, zirconia, or a combination thereof. The moisture permeability of the second shell is preferably measured by the ASTM F 1249 method at a temperature of 38 ° C and a relative humidity of 90% M2 / day, less than 0.7 g / m2 / day, less than 0.6 g / m2 / day, a water vapor transmission rate (WVTR) of less than about 1 g / Less than 0.5 g / m2 / day, less than 0.4 g / m2 / day, less than 0.3 g / m2 / day, less than 0.2 g / m2 / day, less than 0.1 g / m2 / day, less than 0.09 g / m2 / day, less than 0.07 / m2 / day, less than 0.06 g / m2 / day, less than 0.05 g / m2 / day, less than 0.04 g / m2 / day, less than 0.03 g / day or less.

The positions of the first shell and the second shell may be changed. That is, a structure may be employed in which a second shell, which serves to block moisture or moisture, surrounds the core and the first shell surrounds the second shell.

Hereinafter, embodiments of the present invention will be described in more detail with reference to Production Examples and Experimental Examples.

≪ Preparation Example 1 &

10 is a schematic diagram of a backlight unit according to an embodiment of the present invention.

A blue LED light source 250 is disposed on both sides of the light guide plate 200 and a reflective sheet 210 is disposed under the light guide plate 200 as shown in FIG. The reflective sheet 210 mainly used a blue reflective sheet including a dye that minimizes reflection of light in the 580 nm to 600 nm band. The light wavelength conversion film 160, the composite optical film 170, the narrow band liquid crystal film 110, the retardation layer 120, and the broadband reflective polarizing film 130 are sequentially stacked on the upper side of the light guide plate 200. As a result, a backlight unit 300 having a laminated structure as shown in FIG. 10 was completed. The narrow band liquid crystal film 110 was formed by aligning a liquid crystal composition blended with a chiral dopant on a liquid crystal so as to have a minimum transmittance at a wavelength of 410 nm (i.e., a center wavelength of a reflection polarized light of 410 nm) and a half width of 60 nm. The broadband reflective polarizing film 130 has a reflective polarizing function over the entire visible light wavelength range of 380 nm to 780 nm. The retardation layer 120 having a retardation value of 140 nm was used and the retardation axis was disposed at an angle of 45 ° with the transmission axis of the broadband reflective polarizing film 130.

≪ Production Examples 2 to 29 >

A narrow band liquid crystal film was used in which the central wavelengths of the reflection polarized light were 410 nm, 420 nm, 430 nm, 440 nm, 450 nm, 460 nm, 470 nm, 480 nm, 490 nm, 500 nm, 510 nm, 520 nm, 530 nm, 540 nm, 550 nm, 560 nm, 570 nm, , 610 nm, 620 nm, 630 nm, 640 nm, 650 nm, 660 nm, 670 nm, 680 nm and 690 nm was used in place of the liquid crystal composition.

<Comparative Example>

A backlight unit was completed in the same manner as in Production Example 1, except that the narrow band liquid crystal film and the retardation layer were omitted.

Experimental Example  One

The backlight units according to Production Examples 1 to 29 and Comparative Example were mounted on a liquid crystal display panel of an LCD TV (product name: UN55JS8500F). The luminance and CIE color coordinates were measured while driving the liquid crystal display panel in the white mode, and the color recall ratio was calculated according to the DCI standard. The results are shown in Table 1 below.

Reflective polarized light
Center wavelength (nm) Luminance
(cd / m &lt; 2 & Relative luminance
(%) X Y Color recall Color recall
Deviation Comparative Example - 577.7 - - - 98.2 - Production Example 1 410 559.7 96.9% 0.0048 0.0104 98.2 100.0% Production Example 2 420 562.5 97.4% 0.0063 0.0150 98.2 100.0% Production Example 3 430 559.3 96.8% 0.0039 0.0088 98.2 100.0% Production Example 4 440 558.1 96.6% 0.0065 0.0133 98.2 100.0% Production Example 5 450 564.5 97.7% 0.0064 0.0155 97.6 99.4% Production Example 6 460 561.7 97.2% -0.0003 -0.0043 98.7 100.5% Production Example 7 470 555.1 96.1% -0.0020 -0.0054 99.1 100.9% Production Example 8 480 553.3 95.8% -0.0023 -0.0009 99.5 101.3% Production Example 9 490 549.3 95.1% -0.0025 -0.0087 99.4 101.2% Production Example 10 500 513.7 88.9% -0.0023 -0.0120 98.5 100.3% Production Example 11 510 486.0 84.1% -0.0023 -0.0120 97.6 99.4% Production Example 12 520 473.8 82.0% -0.0020 -0.0130 95.7 97.4% Production Example 13 530 461.6 79.9% -0.0020 -0.0130 93.7 95.4% Production Example 14 540 439.6 76.1% 0.0002 -0.0074 93.9 95.6% Production Example 15 550 442.4 76.6% -0.0052 0.0020 95.8 97.6% Production Example 16 560 456.4 79.0% -0.0017 0.0058 97.1 98.8% Production Example 17 570 497.4 86.1% -0.0018 0.0058 98.6 100.4% Production Example 18 580 502.6 87.0% -0.0019 0.0014 100.6 102.4% Production Example 19 590 505.5 87.5% -0.0032 0.0051 99.2 100.1% Production example 20 600 523.7 90.7% -0.0032 0.0051 94.9 96.6% Production Example 21 610 527.5 91.3% -0.0046 -0.0007 94.0 95.7% Production Example 22 620 534.1 92.5% 0.0007 0.0053 94.9 96.6% Production Example 23 630 540.5 93.6% 0.0019 0.0006 96.8 98.5% Production Example 24 640 539.7 93.4% 0.0013 0.0000 97.7 99.5% Production example 25 650 551.3 95.4% 0.0052 0.0010 97.4 99.2% Production Example 26 660 551.9 95.5% 0.0021 -0.0002 97.4 99.1% Production Example 27 670 552.5 95.6% 0.0022 -0.0003 97.3 99.1% Production Example 28 680 556.1 96.3% 0.0023 -0.0002 97.9 99.7% Production Example 29 690 559.7 96.9% 0.0023 -0.0002 97.5 99.3%

In Table 1, the luminance represents the measured luminance value, and the relative luminance represents the relative luminance as a percentage of the comparative example. x and y are CIE chromaticity coordinate values, and DELTA x and DELTA y represent differences in color coordinates relative to the comparative example. The color recall ratio deviation is a relative color recall ratio as a percentage of the comparative example.

Referring to Table 1, the production examples (Production Example 7-9) including the narrow band liquid crystal film having the central wavelengths of 470 nm, 480 nm and 490 nm exhibited higher color reproducibility than the Comparative Example 1, Was relatively small. Also, it can be confirmed that the production examples (Production Example 17-19) including a narrow band liquid crystal film having a central reflection wavelength of 570 nm, 580 nm and 590 nm exhibited a higher color reproduction ratio than the other wavelength ranges in the vicinity.

&Lt; Preparation Example 30 &

A backlight unit was completed in the same manner as in Production Example 1, except that the first narrow-band liquid crystal film was placed underneath the narrow-band liquid crystal film and the second narrow-band liquid crystal film was laminated thereon. The retardation layer was disposed on top of the second narrow band liquid crystal film.

The first narrow-band liquid crystal film was manufactured using a liquid crystal composition having a central reflection wavelength of 480 nm and a half-width of 60 nm, and the second narrow-band liquid crystal film was manufactured using a liquid crystal composition having a central reflection wavelength of 570 nm and a half- Respectively.

&Lt; Production Examples 31 to 34 >

A backlight unit was manufactured in the same manner as in Production Example 30, except that a liquid crystal composition having a central wavelength of reflected polarized light of 580 nm, 590 nm, 600 nm, and 610 nm was used as the second narrow band liquid crystal film.

&Lt; Production Example 35 >

A backlight unit was produced in the same manner as in Production Example 30, except that the first narrow-band liquid crystal film was used with a liquid crystal composition having a central reflection polarized light wavelength of 490 nm.

&Lt; Preparation Examples 36 to 39 &

A backlight unit was manufactured in the same manner as in Production Example 35, except that a liquid crystal composition having a central wavelength of reflected polarized light of 580 nm, 590 nm, 600 nm, and 610 nm was used as the second narrow band liquid crystal film.

&Lt; Production Example 40 &

A backlight unit was produced in the same manner as in Production Example 31, except that the retardation film was omitted.

&Lt; Preparation Example 41 &

A backlight unit was produced in the same manner as in Production Example 36, except that the retardation film was omitted.

Experimental Example  2

The backlight units according to Production Examples 1 to 29 and Comparative Example were mounted on a liquid crystal display panel of an LCD TV (product name: UN55JS8500F). The luminance and CIE color coordinates were measured while driving the liquid crystal display panel in the white mode, and the color recall ratio was calculated according to the DCI standard. The results are shown in Table 2 below.

Reflective polarized light
Center wavelength (nm) Phase difference
film Luminance
(cd / m &lt; 2 & Relative luminance
(%) Color recall Color recall
Deviation Comparative Example - - 577.7 - 98.2 - Production Example 30 480/570 O 450.2 77.93 99.2 101.0% Production Example 31 480/580 O 485.6 84.06 104.0 105.9% Production example 32 480/590 O 489.3 84.70 101.8 103.7% Production Example 33 480/600 O 499.6 86.48 100.9 102.7% Production example 34 480/610 O 495.6 85.79 99.1 100.9% Production example 35 490/570 O 420.8 72.84 100.4 102.2% Production Example 36 490/580 O 476.4 82.46 103.5 105.4% Production example 37 490/590 O 482.7 83.56 101.8 103.7% Production Example 38 490/600 O 498.0 86.20 101.0 102.9% Production example 39 490/610 O 498.0 86.20 98.7 100.5% Production example 40 480/580 X 517.3 89.54 100.6 102.4% Production example 41 490/580 X 524.1 90.72 97.8 99.6%

Referring to Table 2, production examples in which a second narrow band liquid crystal film having a center wavelength of 580 nm and a reflection polarized center wavelength of about 580 nm are stacked on a first narrow band liquid crystal film having a central reflection wavelength of 480 nm or 490 nm, It can be seen that it is effective. On the other hand, Production Examples 31 and 36 to which a retardation film was applied under the same first and second narrow band liquid crystal film lamination conditions exhibited a higher color reproducibility than Production Examples 40 and 41 which did not use a retardation film and applied a retardation film Which is advantageous for improving the color recall ratio.

11 is a graph showing the optical spectrum of light emitted when the backlight unit according to Comparative Example and Production Example 31 is mounted on a liquid crystal display panel and driven in a white mode. Referring to FIG. 11, it can be seen that, in the case of the backlight unit according to Production Example 31, the optical spectrum narrow band liquid crystal films reduce the luminance around the central wavelength of the reflected polarized light.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

100: optical member
110: narrow band liquid crystal film
120: Wavelength control film
130: Broadband reflective polarizing film

Claims (18)

A narrowband reflection polarizer; And
And a broadband reflective polarizer laminated on the narrowband reflective polarizer,
And the width of the reflection polarized light wavelength band of the narrowband reflection polarized portion is smaller than the width of the reflection polarized light wavelength band of the wideband reflection polarized portion. The method according to claim 1,
And a reflection polarized wavelength band of the narrowband reflection polarized portion is contained within a wavelength band of reflected polarized light of the wideband reflective polarized portion. 3. The method of claim 2,
And the wavelength range in which the broad-band reflection polarized light is reflected and polarized is 380 nm to 780 nm. 3. The method of claim 2,
Wherein a reflection central wavelength of the narrow band reflection polarizing portion is in a range of 470 nm to 490 nm or in a range of 570 nm to 590 nm. 5. The method of claim 4,
And a reflection half-width of the narrow-band reflection polarizing portion is 70 nm or less. 6. The method of claim 5,
And the section corresponding to the central wavelength and the half-width of the reflection polarized light of the narrowband reflection polarizing section does not overlap with the blue, green, and red peak wavelengths. The method according to claim 1,
Wherein the narrowband reflection polarizing section reflects circularly polarized light and the broadband reflective polarizing section reflects linearly polarized light. 8. The method of claim 7,
Wherein the narrowband reflection polarizing section includes a cholesteric liquid crystal having a center wavelength of the reflected polarized light of 470 nm to 490 nm and a cholesteric liquid crystal having a central wavelength of the reflected polarized light of 570 nm to 590 nm. 9. The method of claim 8,
Wherein the narrow band reflection polarizing section includes a first cholesteric liquid crystal layer having a center wavelength of the reflected polarized light of 470 nm to 490 nm and a second cholesteric liquid crystal layer having a central wavelength of the reflected polarized light of 570 nm to 590 nm. 10. The method of claim 9,
And the second cholesteric liquid crystal layer is disposed on an emitting portion side of the first cholesteric liquid crystal layer. The method according to claim 1,
Wherein the narrow band reflection polarizing section includes a cholesteric liquid crystal layer and a retardation layer. 12. The method of claim 11,
Wherein the phase difference layer converts circularly polarized light having passed through the cholesteric liquid crystal layer into linearly polarized light, wherein the converted linearly polarized light is different from the transmission axis of the broadband reflective polarized light portion. 13. The method of claim 12,
And the converted linearly polarized light is perpendicular to the transmission axis of the broadband reflective polarizer. The method according to claim 1,
Wherein the optical member is provided with light having a first high peak, a second high peak, and a first low peak peak positioned between the first high peak and the second peak,
Wherein a wavelength distance between a central wavelength of a reflected polarized light of the narrowband reflection polarizing section and the first low peak peak adjacent thereto is smaller than a wavelength distance between a peak peak of the reflection polarized light and an adjacent high peak. 15. The method of claim 14,
And a section corresponding to a reflected central wavelength and a half-width of the narrow-band reflection polarizing section do not overlap with the first high peak and the second high peak. 16. The method of claim 15,
Wherein the first low peak peak is included in a section corresponding to a reflection half-width of the narrow-band reflection polarizer. 15. The method of claim 14,
Wherein the main traveling direction of the light in the optical member is the narrow band reflection polarizing portion and the wide band reflective polarizing portion. An optical device comprising: an optical member according to any one of claims 1 to 17; And
And a liquid crystal display panel disposed on the optical member.

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