KR20090124632A - Circularly polarized light conversion element and brightness enhancing element and the fabrication method thereof - Google Patents

Abstract

PURPOSE: A circularly polarized light conversion device, a luminance improving device, and a manufacturing method thereof are provided to increase production efficiency by using one dielectric thin film different from a multilayer thin film structure. CONSTITUTION: A luminance improving device(20) includes a substrate(21), a first dielectric thin film layer(22), a second dielectric thin film layer(23), and a third dielectric thin film layer(24). The substrate is made of glass or polymer. The first dielectric thin film layer is deposited to a top part of the substrate. The second dielectric thin film layer is deposited to a top part of the first dielectric thin film layer. The third dielectric thin film layer is deposited to a top part of the second dielectric thin film layer. The first dielectric thin film layer and the third dielectric thin film layer are formed by an anisotropic thin film layer of a zigzag structure. The second dielectric thin film layer is formed by an anisotropic thin film layer of a spiral structure.

Description

Circularly polarized light conversion element and brightness enhancing element and the fabrication method

The present invention relates to a circularly polarized light conversion device, a brightness enhancement device and a fabrication method thereof, and more particularly, to deposit a dielectric material at an oblique incidence angle using a complex structure of an oblique incidence deposition method to form a zigzag or spiral dielectric thin film layer. The present invention relates to a circularly polarized light conversion element, a brightness enhancement element, and a method of manufacturing the same, which can easily produce a circularly polarized light conversion element and a brightness enhancement element by lamination.

In general, the quarter wave plate is manufactured by adjusting the thickness such that the phase difference with respect to transmitted light is π / 2 or π using optical birefringence. The quarter wave plate thus manufactured converts linearly polarized light into circularly polarized light or rotates the linearly polarized light by 90 °.

In addition, the 1/2 wave plate serves to change the direction of circularly polarized light in the case of incident circularly polarized light. Such optical phase retardation plate is widely used in various optical devices for controlling polarization components such as liquid crystal display, optical isolator, optical pickup device, laser resonator, optical communication device, light emitting device, optical computing device, plasma display device, etc. do.

In addition, an optical element that transmits or reflects circularly polarized light with respect to one wavelength according to a circularly polarized state is used by sealing a liquid cholesteric liquid crystal made of a low molecular weight in an alignment state between substrates such as glass. .

The circularly polarized light separating device manufactured as described above is widely used in various optical devices for controlling polarization components such as liquid crystal display, optical pickup device, light emitting device, optical communication device, light emitting device, and optical operation device.

Here, the wavelength to transmit or reflect the circularly polarized light according to the circularly polarized state is determined by the average refractive index of the liquid crystal and the thickness of the spiral pitch of the cholesteric phase. As such, the wavelength of the crystal for transmitting or reflecting the circularly polarized light at the desired wavelength can be selected by the thickness of one spiral and the average refractive index of the cholesteric liquid crystal phase.

In addition, 3M's DBEF is typically used for a conventional brightness enhancement device. The DBEF transmits only one polarization component to incident light and reflects light in another polarization state, thereby causing the reflected light to be unpolarized again by the reflector. When the light is changed to light, and the light converted into the unpolarized light is reflected and re-injected into the device is repeated, the efficiency of the light is maximized by maximizing the loss of light.

On the other hand, in the case of circularly polarized light incident by depositing a zigzag half wave plate of a zigzag structure and an anisotropic thin film of a spirally circular circularly polarized light separating element in a stack, the circularly polarized light conversion element which transmits by changing the polarization direction of circularly polarized light Log application is possible, and a zigzag quarter wave plate on both sides of a glass substrate is fabricated, and then a linearly polarized light is applied to a linearly polarized light incident by depositing a circular circularly polarized light separating element in the center. It is also possible to apply the optical element to improve the brightness of the light through a series of repetitive process of incident by the reflecting plate again to the unpolarized light by reflecting the silver by using the reflecting plate.

In the conventional luminance improving device, some polarization components of light incident in the vertical direction are used as an element to improve luminance by using a series of repetitive processes that are reflected and returned. The brightness enhancing device is manufactured using a structure of a multilayer thin film in which high refractive index and low refractive index materials are alternately deposited.

On the other hand, in general, the manufacture of an optical device for adjusting the optical properties is usually using a physical vapor deposition method. The physical vapor deposition method using the dielectric has the advantage of being able to coat a large area and to deposit a thin film resistant to the external environment.

On the other hand, the dielectric thin film deposited by the conventional physical vapor deposition method is almost optically isotropic, and since the pillar microstructure of the thin film grows vertically, polarization separating the circular and linearly polarized light with a small number of three layers or less There is a problem that it is difficult to apply to the device.

On the other hand, oblique incidence deposition methods are described in Seouk-Hoon Woo and Chang Kwon Hwangbo, "Optical Anisotropy of Microstructure-Controlled TiO2 Films Fabricated by Glancing-Angle Deposition" Journal of the Korea physical society 48, 2006 and K. Robbie and MJ Brett, " Sculptured thin films and glancing angle deposition: Growth mechanics and applications "J. Vac. Sci. Technol. A 13 (3), 1997, etc., explain the principles of thin film growth and column structure, and describe how to control thin film column structure.

At this time, the thin film deposited by the oblique incident deposition method is grown into a thin film having a porous microstructure by the shadow effect of the thin film micropillar as the oblique incident angle increases (HA Macleod, Thin-film Optical Filter, 3rd ed 2001), in the case of depositing the oblique incident angle largely, the porosity of the thin film is increased by the column structure and the shadow effect, and the effective refractive index of the thin film is decreased.

As described above, the inclined incident deposition method is used in US Patent 6,908,538 B2, which increases the porosity of the thin film deposited in the deposited structure while rotating the substrate by the inclined incident deposition method. It is used as a method of measuring the change of the electrical signal due to bonding and using it to produce an electrochemical gas sensor with excellent reaction time and sensitivity. However, most of the thin films deposited by the gradient incidence deposition method are characterized by electrical and mechanical characteristics using microstructure. It is used but is limitedly used.

In addition, in the case of the existing luminance improving device, in Korean Patent No. 10-0710734, a luminance enhancement filter is manufactured using one or more mixtures in the case of the luminance enhancement filter, and in Korean Patent No. 10-0624307, the luminance enhancement multilayer is applied. In the case of an optical film, several films using the structure of a multilayer thin film are laminated | stacked and manufactured.

As such, the existing brightness enhancing elements are made of using a polarizing film of 3M company or using a conventional polarizing sheet.

Accordingly, an object of the present invention is to manufacture a circular polarization splitting device capable of separating incident circularly polarized light by manufacturing 1/2 and 1/4 wavelength plates by controlling the thickness by thin film anisotropy during thin film deposition. The present invention provides a circularly polarized light conversion device, a brightness enhancing device, and a method of manufacturing the same, which can be fabricated as a circularly polarized light conversion device that can change the polarization direction of one wavelength with respect to circularly polarized light.

In addition, an object of the present invention is to easily fabricate a brightness enhancement device by depositing a wavelength plate on the circularly polarized light separating element, the circularly polarized light conversion element and the brightness enhancement element such that the brightness enhancement element is stable to heat and excellent in transmittance To provide a method of making the same.

An object of the present invention is to use the principle of the optical thin film anisotropic refractive index of the thin film is a circular polarization conversion that can be applied to an optical display system that can improve the light efficiency by using a wavelength selected by controlling the thickness of the thin film is deposited An element, a brightness enhancing element, and a method of manufacturing the same are provided.

In the circular polarization conversion device using the inclined incident deposition method according to the present invention for achieving the above object of the present invention, a first dielectric thin film layer deposited on the substrate, and a second dielectric thin film layer deposited on the dielectric thin film layer Characterized in that consists of.

The first dielectric thin film layer is an anisotropic thin film layer having a zigzag structure, and the second dielectric thin film layer is an anisotropic thin film layer having a spiral structure.

The first dielectric thin film layer is a quarter wave plate deposited with a thickness satisfying a phase difference Δφ = (2πd / λ) (n _x -n _y ), and the second dielectric thin film layer is formed with a pitch thickness of the anisotropic refractive index thin film. It is characterized in that the circularly polarized light separating element that transmits only one circularly polarized light by the rotation direction of the substrate.

The first dielectric thin film and the second dielectric thin film may have a refractive index higher than that of the substrate.

The first dielectric thin film layer is characterized in that the half wave plate formed by adjusting the anisotropic refractive index and thickness.

The substrate is characterized in that the transparent material made of glass or polymer.

The first dielectric thin film layer and the second dielectric thin film layer are dielectric materials having a low absorption rate of 0.01% or less in the wavelength region to be used, and the dielectric materials are TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , CeO ₂ , Si, Bi ₂ O ₃ , SnO ₂ , WO ₃ , HfO ₂ , MoO ₃ It is characterized by consisting of a metal oxide comprising at least any one or more of them.

The brightness improving element according to the present invention for achieving the above object of the present invention,

A brightness enhancing element using an oblique incidence deposition method, comprising: a first dielectric thin film layer deposited on an upper portion of a substrate, a second dielectric thin film layer deposited on an upper portion of the first dielectric thin film layer, and a second dielectric thin film layer deposited on an upper portion of the second dielectric thin film layer And a third dielectric thin film layer.

The substrate is characterized in that the transparent material made of glass or polymer.

The first dielectric thin film layer and the third dielectric thin film layer may be an anisotropic thin film layer having a zigzag structure, and the second dielectric thin film layer may be an anisotropic thin film layer having a spiral structure.

The first dielectric thin film layer is a quarter wave plate deposited with a thickness satisfying a phase difference Δφ = (2πd / λ) (n _x -n _y ), and the second dielectric thin film layer is formed with a pitch thickness of the anisotropic refractive index thin film. It is characterized in that the circularly polarized light separating element that transmits only one circularly polarized light by the rotation direction of the substrate.

The first dielectric thin film, the second dielectric thin film, and the third dielectric thin film may have a refractive index higher than that of the substrate.

The brightness improving element further comprises a polarizer on the front or the rear, characterized in that to further install a reflector on the back of the polarizer.

The first dielectric thin film layer, the second dielectric thin film layer, and the third dielectric thin film layer are dielectric materials having a small absorption rate of 0.01% or less in a wavelength region to be used, and the dielectric materials are TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , CeO ₂ , Si, Bi ₂ O ₃ , SnO ₂ , WO ₃ , HfO ₂ , MoO ₃ It is characterized by consisting of a metal oxide comprising at least any one or more of them.

The method for manufacturing the circularly polarized light conversion element and the brightness enhancement element according to the present invention for achieving the above object of the present invention is a method for manufacturing the circularly polarized light conversion element and the brightness enhancement element using a gradient incidence deposition method, the predetermined method on the substrate; And depositing a first dielectric thin film layer having a zigzag structure at an angle, and depositing a second dielectric thin film layer having a helical structure on top of the first dielectric thin film layer.

A brightness enhancing device is fabricated by depositing a third dielectric thin film layer having a zigzag structure on the second dielectric thin film layer, and when the first dielectric thin film layer is made of a half wave plate, a circularly polarized light conversion device is fabricated. It is done.

The first dielectric thin film layer and the third dielectric thin film layer are characterized in that the quarter wave plate.

The first dielectric thin film layer and the second dielectric thin film layer are characterized in that for depositing the inclined angle of incidence in the range of 30 ° to 90 °.

The first dielectric thin film layer and the second dielectric thin film layer are deposited while rotating the substrate, wherein the rotation speed of the substrate is 0.5rpm or less, and the deposition rate of the substrate is characterized in that the deposition at more than 0.3nm / s.

According to the circularly polarized light conversion device and the brightness enhancing device as described above, and a method of manufacturing the same, the cost can be reduced by depositing a dielectric thin film while controlling the microstructure of the thin film using general optical thin film processing equipment, and the conventional multilayer thin film structure. Compared to the manufacturing process is simple and the process time is reduced, there is an effect that can be reduced cost.

In addition, the present invention uses a single dielectric thin film as compared to the conventional multilayer thin film structure, which is thermally stable and mechanically robust, and uses a single material when depositing a thin film. Evaporation equipment can be used, and even a large area substrate can be manufactured with the same thickness, thereby increasing production efficiency.

In addition, the present invention can select the wavelength of the transmission or reflection of light compared to the conventional brightness enhancement device, its application field is wide, and it is possible to manufacture a circularly polarized light conversion device and a brightness enhancement device using a single material to reduce the contamination of equipment. It can be reduced, and there is an effect that both the circular polarization conversion element and the brightness enhancement element can be manufactured using the same equipment.

Since the present invention uses an optical thin film, it is easy to adjust the optical thickness to produce a thin film of a desired shape, and the dielectric material is used, the transmittance is excellent at the wavelength used for its optical properties, and the range of wavelength selection is wide. In addition, it is possible to transmit the linearly polarized light incident to the linearly polarized light in the other direction by manufacturing the brightness enhancement device, which has a wide range of applications.

The present invention can not only change the polarization direction of the incident circularly polarized light in the case of the circularly polarized light conversion element, but also can easily adjust the transmitted or reflected circularly polarized light in the rotational direction of the spiral structure, and in the case of the brightness enhancement device, the spiral structure The circularly polarized light reflected according to the rotation direction of the light is changed back to unpolarized light by using a reflecting plate, and then returned to the luminance enhancing device to increase light efficiency.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar elements.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described in the specification, and one or more other It is to be understood that the present invention does not exclude the possibility of the presence or the addition of features, numbers, steps, operations, components, parts, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention.

1 is a cross-sectional view showing a structure of a brightness enhancement device according to an embodiment of the present invention, Figure 2 is a cross-sectional view showing a structure of a circular polarization conversion device according to an embodiment of the present invention.

1 and 2, the brightness enhancing device 20 according to an exemplary embodiment of the present invention may include a substrate 21 made of glass or a polymer and a first dielectric thin film layer deposited on the substrate 21. 22), a second dielectric thin film layer 23 deposited on the first dielectric thin film layer 22, and a third dielectric thin film layer 24 deposited on the second dielectric thin film layer 23.

In this case, the first dielectric thin film layer 22 and the third dielectric thin film layer 24 are zigzag anisotropic thin film layers, and the second dielectric thin film layer is a spiral anisotropic thin film layer.

Meanwhile, the circularly polarized light conversion element according to another embodiment of the present invention includes the substrate 21, the first dielectric thin film layer 22, and the second dielectric thin film layer 23.

That is, as shown in FIG. 2, the circularly polarized light conversion element fabricates the first dielectric thin film layer 22, which is a half-wave plate, using a zigzag structure on the transparent substrate 21, and the first dielectric thin film layer. The upper portion of the 22 is fabricated using the second dielectric thin film layer 23 having a spiral structure.

Here, the second dielectric thin film layer 23 is transmitted in the case of the right circular polarization incident as the rotation direction rotates counterclockwise, and is reflected in the case of the left circular polarization. In addition, in the case of the transmitted right circularly polarized light is transmitted to the left circularly polarized light while passing through the half-wave plate of the zigzag structure.

Meanwhile, the first dielectric thin film layer 22 and the third dielectric thin film layer 24 are formed to have a phase difference by being deposited to a thickness satisfying Equation 1 below, and the phase difference is circularly polarized light from the incident linearly polarized light. It is a quarter wave plate which changes into, and the half wave plate which changes the circularly polarized direction of the circularly polarized light.

(Equation 1)

Δφ = (2πd / λ) (n _x -n _y )

In Equation 1, d denotes a moving distance of light to pass through the medium, that is, a thickness of a thin film, λ denotes a wavelength of incident light, and nx denotes a refractive index of a material with respect to light vibrating in the x direction. Ny represents the refractive index of the material with respect to light oscillating in the y direction.

The second dielectric thin film layer 23 becomes a circularly polarized light separating element that transmits only one circularly polarized light by the pitch thickness of the anisotropic refractive index thin film and the rotation direction of the substrate 21.

In particular, the first dielectric thin film layer 22 serves to change the circularly polarized light back to linearly polarized light by the thickness of the thin film when the quarter wave plate is manufactured.

The brightness enhancing element formed as described above is relatively heat stable because it uses a dielectric, and the manufacturing process is simple, and since it is manufactured in the form of a thin film, it can be manufactured thinly and has a wide range of wavelengths to be selected. The application is not only possible, but also as a polarization direction conversion element that can transmit and change the polarization state of incident light.

As described above, the circularly polarized light conversion element and the brightness enhancement element according to the embodiment of the present invention use a gradient incidence deposition method. The gradient particle deposition method is capable of depositing a thin film having an anisotropic structure by the pillar microstructure of the dielectric thin film. This may cause zigzag and helical thin films to be deposited.

This polarization component of the linearly polarized light incident by using the oblique incidence deposition method is transmitted to exhibit an optical characteristic of being transmitted by linearly polarized light having different phases. In addition, circularly polarized light that is not transmitted is reflected and converted into unpolarized light by using a reflector of the optical system. The reflected light is then reincident into the device, a series of reincident steps are repeated, and the light efficiency is increased.

Such optical anisotropy is described by Seouk-Hoon Woo and Chang Kwon Hwangbo, "Optical Anistropy of Microstructure-Controlled TiO2 Films fabricated by Glancing angle deposition," J. Korea Phys. Soc. As described in 48 1199-1204, 2006, the optical anisotropy of the dielectric optical thin film can be controlled by depositing the dielectric optical thin film by gradient incidence deposition.

At this time, the cause of the anisotropy and the deposition condition in which the optical anisotropy is maximized are the refractive index decreases from about 1.99 to 1.5 when the inclination angle increases from 0 ° to 80 ° when the TiO ₂ thin film is deposited by gradient incidence deposition. The anisotropy is greatest when the incidence angle of inclination is about 60 °.

Hereinafter, a method of manufacturing the circularly polarized light conversion element and the brightness enhancement element according to an embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 3 is a view schematically illustrating a zigzag deposition method in a method of fabricating a circularly polarized light conversion device and a brightness enhancement device according to an embodiment of the present invention, and FIG. 4 is a circularly polarized light conversion and brightness enhancement device according to an embodiment of the present invention. Fig. 5 is a cross-sectional view of a column growth direction of a thin film deposited by the method of fabrication using SEM measurement equipment. FIG. 5 is a transmission spectrum of a polarizer of a quarter wave plate in which a TiO ₂ thin film is deposited by the zigzag deposition method of FIG. FIG. 6 is a diagram illustrating a transmission spectrum by a polarizer of a 1/2 wave plate in which a TiO ₂ thin film is deposited by the zigzag deposition method of FIG. 3, and FIG. 7 is a circularly polarized light conversion according to an embodiment of the present invention. FIG. 8 is a view schematically illustrating a method of depositing a circularly polarized light separating device among methods of fabricating a device and a brightness enhancing device, and FIG. 8 is a SEM cross-sectional view of the circularly polarized light separating device deposited by FIG. 7. FIG. 9 is a diagram illustrating the transmission spectrum of the circularly polarized light separating element of the luminance enhancement device deposited by FIG. 7, and FIG. 10 is the transmission of the circularly polarized light separation element of the brightness enhancement element deposited by FIG. 7. FIG. 11 is a diagram illustrating a spectrum difference, and FIG. 11 is a diagram illustrating a transmission spectrum of circularly polarized light incident using a circularly polarized light conversion element according to an embodiment of the present invention, and FIG. 12 is a diagram illustrating an embodiment of the present invention. FIG. 13 is a cross-sectional view of the luminance enhancing device manufactured by the method of manufacturing the circularly polarized light conversion element and the luminance enhancement device, and FIG. 13 is a diagram illustrating a transmission spectrum of linearly polarized light of the luminance enhancement device of FIG. 12.

3 to 13, the method of manufacturing the luminance improving element 20 according to the exemplary embodiment of the present invention may include a first dielectric thin film layer 22 having an anisotropic zigzag structure on a substrate 21 having a transparent material. The second dielectric thin film layer 23 having an anisotropic spiral structure and the third dielectric thin film layer 24 having an anisotropic zigzag structure are sequentially stacked on the first dielectric thin film layer 22.

In this case, the circular polarization conversion element according to the embodiment of the present invention is formed by stacking the first dielectric thin film layer 22 and the second dielectric thin film layer 23 on the substrate 21.

The circularly polarized light conversion element and the brightness enhancement element are deposited on the substrate 21 having the inclined incident angle α of a predetermined angle so that the phase difference and transmittance are adjusted by adjusting the deposition thickness of the dielectric thin film layers 22, 23, and 24.

In addition, the dielectric thin film layers 22, 23, and 24 have a refractive index higher than that of the substrate 21, and are a dielectric material having a small absorbance of 0.01% or less in a wavelength range to be used, and are made of TiO ₂ , ZrO ₂ , and Ta _2. O ₅ , CeO ₂ , Si, Bi ₂ O ₃ , SnO ₂ , WO ₃ , HfO ₂ , MoO ₃ It is preferable that it consists of a metal oxide which contains at least any one or more of these.

In addition, the dielectric thin film layers 22, 23, and 24 deposit an inclination angle α within a range of 30 to 89 degrees. When the inclination angle is 30 degrees or less, the anisotropic characteristic of the thin film is markedly small, indicating almost isotropic characteristics. If it is 89 degrees or more, it becomes difficult to deposit a thin film.

The second dielectric thin film layer 23 is formed while forming a microstructure in an inclined structure and rotating the substrate 21 at 0.5 rpm or less, and the rotation speed of the substrate 21 is increased to 0.5 rpm or more. In this case, the anisotropic characteristic due to the spiral structure of the thin film does not appear.

At this time, in the present invention, the second dielectric thin film layer is deposited on the substrate, but it is also possible to manufacture the optical element by controlling the polarization state of the transmitted or reflected light by depositing on the optical thin film or metal having a multilayer structure.

As shown in FIG. 3, the zigzag deposition method is a method of depositing the substrate 21 to be inclined at an angle of α so that the vaporized particles are incident to the substrate 21 at an angle of inclination of the substrate 21. Since the inclination angle α can be varied from 0 ° to 90 °, the substrate 21 is changed from the inclination angle α to -α and subsequently deposited.

Such an inclined incident deposition method can be implemented by changing the structure so that only the inclination angle of the substrate can be tilted in a physical vapor deposition machine that deposits a thin film by heating an electron beam in a high vacuum state, and thus the dielectric thin film made of the zigzag structure exhibits anisotropic characteristics do.

As shown in FIG. 4, in the case of a thin film on which 1/2 and quarter wave plates are deposited using the zigzag deposition method, the columnar structure has a zigzag shape. This formation results in an anisotropic refractive index in which the anisotropic characteristic is exhibited by this empty space.

FIG. 5 is a diagram illustrating a transmission spectrum by a polarizer of a quarter wave plate in which a TiO ₂ thin film is deposited by the zigzag deposition method of FIG. 3.

As shown in FIG. 5, the linearly polarized light incident by a polarizer (not shown) installed in front of the brightness enhancing element is changed into circularly polarized light, and is again converted into linearly polarized light by the polarizer installed at the rear side. It shows what is transmitted.

In the case of the quarter wave plate using the zigzag deposition method, the incident light is converted into linearly polarized light by forming a polarizer on the front and the rear side, and the linearly polarized light is thus incident on the quarter wave plate. And a quarter wave plate in which the polarization of light transmitted through the direction of the polarizer on the rear surface is changed.

As shown in FIG. 6, the TiO ₂ anisotropic thin film was deposited by the zigzag deposition method, and the thickness of the TiO ₂ anisotropic thin film was controlled to produce a half wave plate, and then transmitted through linearly polarized light using the polarizer.

 As shown in FIG. 7, in the case of the circularly polarized light separating element, the substrate 21 is tilted and deposited, and at the same time, the left or right polarized light can be transmitted or reflected by the rotation direction of the substrate, and can be adjusted. By controlling the thickness of the pitch deposited as it rotates, it is possible to select the wavelength at which the circularly polarized light is separated.

In this case, the rotational speed of the substrate 21 is reduced to 0.5 rpm or less, and the deposition rate is deposited to 0.3 nm / s or more, and the inclination angle α may be changed from 0 ° to 90 °. If the deposition rate is less than 0.3 nm / s, circularly polarized light separation due to the anisotropic property of the thin film is not easily seen.

FIG. 8 illustrates that the pillar microstructure of the thin film grows in a spiral shape in accordance with the rotation of the substrate 21 in the process of depositing the dielectric thin film layer 23 having the spiral structure, and the circular polarization through three rotations in the process of depositing. It shows a cross-sectional view of the separation element.

As shown in FIG. 9, after injecting light of different circularly polarized states into the circularly polarized light separating element, the transmission spectrum shows a transmittance difference of about 50% at a wavelength of 670 nm.

As shown in FIG. 10, the difference in transmittance after the incidence of different circularly polarized light incident on the circularly polarized light separating element is shown, and the result of the computer simulation using a computer program for circularly polarized light separation before the deposition of the circularly polarized light separating element is performed. The circularly polarized light splitting device can be made to be well matched with, and based on these results, the circularly polarized light splitter can be made to separate the circular polarized light at any wavelength to be used.

11 shows that the circularly polarized light conversion element separates the left circularly polarized light and the right circularly polarized light at 510 nm. The incident circularly polarized light passes through the helical dielectric thin film layer 23 for one wavelength. Only circularly polarized light in one direction is transmitted, and the polarized light direction of circularly polarized light is transmitted while passing through the 1/2 wave plate.

In addition, as another embodiment of the present invention, the incident right polarized light passes through the dielectric thin film layer of the spiral structure formed in the left circle, and the right polarized light is transmitted, and the left circle polarized light may be reflected at one wavelength. The transmitted right polarized light is changed to the left circle polarized light while passing through the 1/2 wave plate again, and only the changed left circle polarized light is transmitted for one wavelength.

As shown in FIG. 12, a first dielectric thin film layer 22, which is a quarter wave plate having a zigzag structure, is formed on the substrate 21, and a second dielectric, which is a circularly polarized light separating element, is formed using a spiral structure thereon. After the thin film layer 23 is formed, the third dielectric thin film layer 24, which is a quarter wave plate having a zigzag structure, is formed on the second dielectric thin film layer 23 again.

Therefore, when the linearly polarized light is incident on the brightness enhancing element 20, the circularly polarized light is changed into circularly polarized light. The circularly polarized light passes through the circularly polarized light separating element of the spiral structure and transmits circularly polarized light in one direction. Passing through the quarter wave plate located above the substrate 21 is converted into linearly polarized light.

Here, in the case of the circularly polarized light reflected by the circularly polarized light splitting device, when the reflecting plate is used, the circularly polarized light is changed into unidirectionally polarized light and reflected again. The reflected light is again converted into linearly polarized light through the polarizer, and a series of processes that are reincident to the brightness enhancing device 20 are repeated and the efficiency is increased.

 As shown in FIG. 13, the luminance improving element has a transmittance of linearly polarized light at 540 nm. The linearly polarized light is incident on the quarter wave plate of the third dielectric thin film layer 24. When the phase is changed to circularly polarized light, the circularly polarized light is passed through the second dielectric thin film layer 23 having a spiral structure so that one circularly polarized light is transmitted for one wavelength and the other circularly polarized light. The reflected light is reflected back to it.

The transmitted circularly polarized light is converted into linearly polarized light having a phase different from that of the linearly polarized light incident through the quarter wave plate, which is the first dielectric thin film layer 22 directly positioned on the glass substrate. .

For example, when the P-polarized polarized wave is incident, it passes through the third dielectric thin film layer 24, which is a quarter wave plate, and is converted into right polarized light, and the right polarized light is a second dielectric thin film layer having a spiral structure ( It passes through 23). In the case of the transmitted circularly polarized light, the first dielectric thin film layer 22, which is a quarter wave plate, is transmitted as S polarized light.

In addition, the incident light is left circularly polarized light passing through the third dielectric thin film layer 24 that is a quarter wave plate in the case of S polarized light, and in the case of the left circularly polarized light, the second dielectric thin film layer having a spiral structure. When the reflective plate is reflected back to one wavelength while passing through (23), and the reflecting plate is located at the rear side, the brightness of the light may be improved through the repeated process of being reflected back to the reflecting plate.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

1 is a cross-sectional view showing the structure of a brightness enhancement device according to an embodiment of the present invention.

2 is a cross-sectional view showing the structure of a circular polarization conversion element according to an embodiment of the present invention.

FIG. 3 is a view schematically illustrating a zigzag deposition method in a method of fabricating a circularly polarized light conversion device and a brightness enhancing device according to an exemplary embodiment of the present invention.

4 is a cross-sectional view of a column growth direction of a thin film deposited by a method of fabricating a circularly polarized light conversion and luminance enhancement device according to an exemplary embodiment of the present invention using an SEM measuring apparatus.

FIG. 5 is a diagram illustrating a transmission spectrum by a polarizer of a quarter wave plate in which a TiO ₂ thin film is deposited by the zigzag deposition method of FIG. 3.

FIG. 6 is a diagram illustrating a transmission spectrum by a polarizer of a 1/2 wave plate in which a TiO ₂ thin film is deposited by the zigzag deposition method of FIG. 3.

FIG. 7 is a view schematically illustrating a method of depositing a circularly polarized light separating element in a method of fabricating a circularly polarized light conversion element and a brightness enhancing element according to an exemplary embodiment of the present invention.

FIG. 8 is a cross-sectional view of the circularly polarized light separating element deposited by FIG.

This is a drawing.

FIG. 9 is a transmission specification of the circularly polarized light separating element of the luminance improving element deposited by FIG.

It is a figure which showed the drum.

10 is a transmission specification of the circularly polarized light separating element of the brightness enhancement element deposited by FIG.

It is a figure which shows the difference of a track.

11 is a circle incident by using the circular polarization conversion element according to an embodiment of the present invention

A diagram showing a transmission spectrum for type polarized light.

12 is a cross-sectional view of the luminance improving element manufactured by the method of manufacturing the circularly polarized light conversion element and the luminance enhancement element according to the embodiment of the present invention.

FIG. 13 is a diagram illustrating a transmission spectrum of linearly polarized light of the luminance improving element of FIG. 12.

*** Explanation of symbols for main parts of drawing ***

20: luminance improving element 21: substrate

22: first dielectric thin film layer 23: second dielectric thin film layer

24: third dielectric thin film layer

Claims (27)

In the circularly polarized light conversion device using a gradient incidence deposition method, A first dielectric thin film layer deposited over the substrate, And a second dielectric thin film layer deposited on the dielectric thin film layer. The method of claim 1, And the first dielectric thin film layer is an anisotropic thin film layer of zigzag structure, and the second dielectric thin film layer is a spiral anisotropic thin film layer. The method of claim 2, And the first dielectric thin film layer is a quarter wave plate deposited with a thickness satisfying a phase difference Δφ = (2πd / λ) (n _x -n _y ). The method of claim 2, And the second dielectric thin film layer is a circularly polarized light separating element that transmits only one circularly polarized light by the pitch thickness of the anisotropic refractive index thin film and the rotation direction of the substrate. The method of claim 1, And the first dielectric thin film and the second dielectric thin film have a refractive index higher than that of the substrate. The method of claim 2, And the first dielectric thin film layer is a half wave plate formed by adjusting anisotropic refractive index and thickness. The method of claim 1, The substrate is a circular polarization conversion element, characterized in that the transparent material made of glass or polymer. The method of claim 1, And the first dielectric thin film layer and the second dielectric thin film layer are dielectric materials having a small absorption rate of 0.01% or less in a wavelength range to be used. The method of claim 8, The dielectric material is TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , CeO ₂ , Si, Bi ₂ O ₃ , SnO ₂ , WO ₃ , HfO ₂ , MoO ₃ The circularly polarized light conversion element which consists of a metal oxide which contains at least any one of these. In the brightness improving element using the oblique incidence deposition method, A first dielectric thin film layer deposited over the substrate, A second dielectric thin film layer deposited on the first dielectric thin film layer; And a third dielectric thin film layer deposited on the second dielectric thin film layer. The method of claim 10, The substrate is a brightness improving element, characterized in that the transparent material made of glass or polymer. The method of claim 10, And the first dielectric thin film layer and the third dielectric thin film layer are zigzag anisotropic thin film layers, and the second dielectric thin film layer is a spiral anisotropic thin film layer. The method of claim 12, And the first dielectric thin film layer is a quarter wave plate deposited with a thickness satisfying a phase difference Δφ = (2πd / λ) (n _x -n _y ). The method of claim 12, And the second dielectric thin film layer is a circularly polarized light separating element that transmits only one circularly polarized light by the pitch thickness of the anisotropic refractive index thin film and the rotation direction of the substrate. The method of claim 10, And the first dielectric thin film, the second dielectric thin film, and the third dielectric thin film have a refractive index higher than that of the substrate. The method of claim 10, The brightness improving element further comprises a polarizer on the front or rear. The method of claim 16, And a reflection plate is further provided on the rear surface of the polarizer. The method of claim 10, And the first dielectric thin film layer, the second dielectric thin film layer, and the third dielectric thin film layer are small dielectric materials having an absorption rate of 0.01% or less in a wavelength region to be used. The method of claim 18, The dielectric material is TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , CeO ₂ , Si, Bi ₂ O ₃ , SnO ₂ , WO ₃ , HfO ₂ , MoO ₃ A luminance enhancing element comprising a metal oxide comprising at least one of at least one of the foregoing. In the manufacturing method of the circularly polarized light conversion element and the brightness enhancement element using a gradient incidence deposition method, Depositing a first dielectric thin film layer having a zigzag structure at a predetermined angle on the substrate; And depositing a second dielectric thin film layer having a spiral structure on top of the first dielectric thin film layer. The method of claim 20, A method of manufacturing a circularly polarized light conversion device and a brightness enhancing device, comprising: depositing a third zigzag third dielectric thin film layer on the second dielectric thin film layer to fabricate a brightness enhancing device. The method of claim 20, A circular polarization converting element and a method for manufacturing a brightness enhancing element, wherein the first dielectric thin film layer is made of a circular polarization converting element when the first dielectric thin film layer is made of a 1/2 wave plate. The method of claim 20 or 21, And the first dielectric thin film layer and the third dielectric thin film layer are quarter wave plates. The method of claim 20, The first dielectric thin film layer and the second dielectric thin film layer is a circular polarization conversion device and the manufacturing method of the brightness enhancement device, characterized in that for depositing inclined incidence angle in the range of 30 ° to 90 °. The method of claim 20, And the first dielectric thin film layer and the second dielectric thin film layer are deposited while rotating the substrate. The method of claim 25, The rotation speed of the substrate is a manufacturing method of the circularly polarized light conversion element and the brightness enhancement element, characterized in that less than 0.5rpm. The method of claim 20, The deposition rate of the substrate is a manufacturing method of the circularly polarized light conversion element and the brightness enhancement element, characterized in that deposited at 0.3nm / s or more.

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