KR102106817B1 - Multilayered filters for controlling color purity and manufacturing method thereof - Google Patents

Abstract

The present invention comprises the steps of: a) cleaning the substrate sequentially with an ultrasonic bath in acetone, alcohol and demineralized water; b) depositing a SiO2 / TiO2 stacking layer using SiO2 and TiO2 targets through a sputtering method; c) annealing the deposited multilayer film at a temperature of 200 to 600 ° C. for 30 to 150 minutes; Disclosed is a method for manufacturing a SiO2 / TiO2 multilayer structure filter comprising a, and the color purity control is adjusted by combining the prepared SiO2 / TiO2 multilayer structure filter with a liquid crystal display, an LED or an OLED to vary the annealing temperature. Disclosed is a more easily adjustable point.

Description

Multilayered filters for controlling color purity and manufacturing method thereof

The present invention relates to a method for manufacturing a SiO ₂ / TiO ₂ multilayer structure filter and the multilayer structure filter coupled to an LCD color filter, LED or OLED.

So far, many studies have been conducted on thin film filters having a multilayer structure.

In particular, in the case of an LCD display, a technique of changing a white backlight light source to RGB color using a color filter is used, but such a technique has a problem in that color purity is lowered due to a limitation in wavelength selectivity of the color filter.

On the other hand, in the case of LED and OLED, there is an advantage that the color purity is relatively good due to the self-emission characteristics of each RGB than the LCD display, but in order to improve the additional color expression power, expensive additional auxiliary materials such as quantum dot films must be used. There is a problem. In particular, in the case of an LED backlight-based LCD or OLED using a color filter, an expensive quantum dot film or the like is essential to improve color purity.

In this situation, studies on many multilayer thin films have been conducted so far. Prior Document 1 relates to a research result that various thickness combinations of SiO2 / TiO2 multi-layer thin films have a great influence on transmittance characteristics, and according to their research results, the red shift of transmittance can be achieved in the range of UV, visible light and IR spectrum. Suggests that there is. On the contrary, according to the prior document 2, it is suggested that the blue shift and the increase in the reflection intensity are possible by changing the number of stacked multilayer films.

However, few studies have been conducted on changes in structural, optical, and filtration characteristics due to the effect of annealing temperature of SiO2 / TiO2 multilayer films.

(1) M. Kitui, M. M Mwamburi, F. Gaitho, C. M. Maghanga, "Optical Properties of TiO2 Based Multilayer Thin Films: Application to Optical Filters", Int. J. Thin Film Sci. Technol. 4 (2015) 17-21. (2) P. Kurt, D. Banerjee, R. E. Cohen and M. F. Rubner, "Structural color via layer-by-layer deposition: layered nanoparticle arrays with near-UV and visible reflectivity bands", J. Mater. Chem. 19 (2009) 8920-8927.

The present invention is designed to solve the above-mentioned problems, and one object of the present invention is to provide a method of manufacturing a SiO2 / TiO2 multilayer structure film combined with an LED light source and an OLED structure and a multilayer structure film produced therefrom.

Another object of the present invention relates to a method of simply adjusting the color purity as needed by depositing an optical filter having a multilayer structure of SiO2 / TiO2 in an LCD color filter and a pre-process or post-process step of LED and OLED.

In order to achieve the above object,

According to one aspect of the invention,

a) cleaning the substrate sequentially with an ultrasonic bath in acetone, alcohol and demineralized water;

b) depositing a SiO2 / TiO2 stacking layer using SiO2 and TiO2 targets through a sputtering method;

c) annealing the deposited multilayer film at a temperature of 200 to 600 ° C. for 30 to 150 minutes;

Provided is a method of manufacturing a SiO 2 / TiO 2 multilayer structure filter comprising a.

In addition, according to another aspect of the present invention, a liquid crystal display (LCD) including a SiO2 / TiO2 multilayer structure filter manufactured according to the above manufacturing method, including a substrate, a color filter, and an external film, between the substrate and the external film A liquid crystal display device is provided, characterized in that the SiO2 / TiO2 multilayer structure filter is disposed.

Further, according to another aspect of the present invention, an organic light emitting diode (OLED) display device including a SiO 2 / TiO 2 multilayer structure filter manufactured according to the above manufacturing method, an encapsulation layer, first and second electrode layers, An organic light emitting diode display device comprising a TFT layer, an OLED layer, a substrate, and an external film, wherein the SiO2 / TiO2 multilayer structure filter is disposed between the substrate and the external film.

Furthermore, as a light emitting diode display device including an LC panel, a light guide plate, a reflector and a light emitting diode (LED), the LC panel, the light guide plate and the reflector are stacked on each other, including a light emitting diode (LED) on the side of the light guide plate, the light emitting diode And a stacked LC panel, a light guide plate, and a reflector, an SiO 2 / TiO 2 multilayer structure filter manufactured according to the above manufacturing method is provided.

Meanwhile, according to an aspect of the present invention, a light emitting diode including a light emitting diode (LED) chip, an epoxy, a phosphor, and a lens, between the LED chip and an epoxy or between a phosphor and a lens, SiO 2 prepared according to the above manufacturing method A light emitting diode comprising a / TiO2 multilayer structure filter is provided.

In addition, in the pre-process or post-process step of the LCD color filter, LED or OLED manufacturing process, the SiO2 / TiO2 multilayer structure filter deposited by annealing at a temperature of 300 to 500 ° C is deposited to improve the color purity of the LCD color filter, LED or OLED. A method of adjustment is provided.

According to the SiO2 / TiO2 multilayer structure film of the present invention, the color purity can be easily adjusted as required by depositing the optical filter of the SiO2 / TiO2 multilayer structure in the pre- or post-process steps of the LCD color filter and LED and OLED. , Deterioration can be prevented through heat treatment of the surface of the SiO2 / TiO2 multilayer structure or the substrate.

1 (a) shows the X-ray diffraction pattern of the SiO2 / TiO2 multilayer film before and after annealing at 300, 400 and 500 ° C, and (b) shows the AFM surface profile of the SiO2 / TiO2 multilayer film annealed at 500 ° C. , (c), (d) and (e) show cross-section bright field TEM, HR-TEM and EDS mapping images of SiO2 / TiO2 films, respectively. (F) also shows the atomic line profiles of Si, Ti and O after annealing at 500 ° C.
Figure 2 shows the optical properties of the SiO2 / TiO2 multilayer thin film before and after heat treatment at a temperature of 300-500 ° C ((a): transmittance (inset shows an enlargement in the range of 520-620 nm), (b): reflectance, (c): Absorbance, (d): FT-IR).
3 shows the optical filter characteristics of the SiO2 / TiO2 multilayer thin film before and after heat treatment at 300-500 ° C, (a), (b) and (c) are emission spectra of red, green and blue light, respectively, and (d) is Indicates the annealing temperature-dependent luminescence intensity of the multilayer film. (Inset shows the top view of the filter on the RGB-LED.)
4 shows a structure in which a multilayer filter is combined with a light emitting diode (LED) chip according to an embodiment of the present invention.
5 shows an LED structure provided with a multilayer filter according to an embodiment of the present invention.
6 shows a structure in which a multi-layer filter is combined with an LCD display color filter according to an embodiment of the present invention.
7 shows a structure applied to an OLED color filter according to an embodiment of the present invention.
Figure 8 shows each thickness of the SiO2 / TiO2 multilayer thin film laminated on a glass substrate according to an embodiment of the present invention.
9 shows a temperature change over time (a) an annealing apparatus and (b) an hour according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention comprises the steps of: a) cleaning the substrate sequentially with an ultrasonic bath in acetone, alcohol and demineralized water;

b) depositing a SiO2 / TiO2 stacking layer using SiO2 and TiO2 targets through a sputtering method;

c) annealing the deposited multilayer film at a temperature of 200 to 600 ° C. for 30 to 150 minutes;

It provides a method of manufacturing a SiO2 / TiO2 multilayer structure filter comprising a.

In step a, the substrate may be a glass substrate, and the thickness is not particularly limited, but may be 0.3 μm to 3 μm, or 0.5 μm to 1 μm.

In addition, the cleaning step may clean the substrate in an ultrasonic bath through a cleaning material, and if the cleaning material and cleaning time correspond to the material and time to clean the substrate, the type or time is not particularly limited. , In particular, the washing may be performed for 5 to 30 minutes, more specifically 10 to 20 minutes through acetone, alcohol and demineralized water. Particularly preferably, acetone, alcohol, and demineralized water can be washed sequentially with an ultrasonic bath for about 15 minutes each.

In addition, the deposition step of step b is preferably carried out in a cluster sputter chamber, the sputter chamber can be injected with pure Ar gas, the flow rate of the Ar gas and the pressure in the sputter chamber belongs to the art. Those skilled in the art can perform the adjustment within a range that can be usually performed. In addition, the deposition rate of SiO2 and TiO2 in the deposition step may also be appropriately selected and adjusted by those skilled in the art from the viewpoint of not significantly departing from the scope of the present invention.

On the other hand, the step c is to perform annealing at a specific temperature for the prepared multi-layer film, the annealing in a box furnace (box furnace), under an oxygen atmosphere, annealing at a temperature of about 300 to 500 ℃ for about 60 to 120 minutes Can be done. The annealing practice temperature may be selected within a range of 300 to 500 ° C by a person skilled in the art in order to adjust the color purity by absorbing or transmitting a specific wavelength region band.

Meanwhile, the SiO2 / TiO2 filter prepared as described above may have a multi-layered structure composed of several layers, and is not limited as much as the number of layers, but may be increased or decreased as necessary, for example, 5 to 13 layers, 7 To 11 layers, or 9 layers.

In addition, the thickness of each layer of the SiO2 / TiO2 multilayer structure filter may vary depending on the needs of wavelength selection. In particular, it is preferable that the multilayer structure has a symmetrical structure around the middle layer.

For example, as shown in FIG. 8, a TiO2 layer and a SiO2 layer may be formed in a cross-section with an SiO2 layer having a cavity structure formed thereon, and the thickness of the SiO2 layer as the center of the multilayer structure is 200. It may be from 800 nm, the thickness of the TiO2 and SiO2 layer formed crossing about the center layer may be 10 to 200 nm, or 30 to 150 nm.

The SiO2 / TiO2 multilayer structure filter manufactured according to the above-described manufacturing method may be applied to a liquid crystal display (LCD) color filter, an organic light emitting diode (OLED) display, a light emitting diode (LED), or a light emitting diode display.

When the SiO2 / TiO2 multilayer structure filter is included in the liquid crystal display device, the liquid crystal display device may include a substrate, a color filter, and an external film, and the SiO2 / TiO2 multilayer structure filter is disposed between the substrate and the external film. Can be.

In addition, when the SiO2 / TiO2 multilayer structure filter is included in the organic light emitting diode display, the organic light emitting diode display includes an encapsulation layer, a first and second electrode layer, a TFT layer, an OLED layer, a substrate, and an external film. The SiO2 / TiO2 multilayer structure filter may be disposed between the substrate and the outer film.

In addition, when the SiO2 / TiO2 multilayer structure filter is included in the light emitting diode, the light emitting diode may include a light emitting diode chip, an epoxy, a phosphor, and a lens, and the SiO2 / TiO2 multilayer structure filter is located between the light emitting diode chip and the epoxy. Or, it may be disposed between the phosphor and the lens.

Furthermore, when the SiO2 / TiO2 multilayer structure filter is included in the LED display device, the LED display device may include an LC panel, a light guide plate, a reflector, and a light emitting diode, and the LC panel, the light guide plate, and the reflector are stacked on each other, and The SiO2 / TiO2 multilayer structure filter may be disposed between the stacked LC panel, the light guide plate, and the reflector and the light emitting diode. As described above, by combining the SiO2 / TiO2 multi-layer structure filter, there is an advantage that it can replace expensive additional subsidiary materials, such as a conventional quantum dot film, used to exhibit relatively good color purity.

Meanwhile, according to another aspect of the present invention, in a pre-process or post-process step of a liquid crystal display (LCD) color filter, light emitting diode (LED), or organic light emitting diode (OLED) manufacturing process, at a temperature of 300 to 500 ° C. A method of controlling the color purity of a liquid crystal display color filter, a light emitting diode or an organic light emitting diode can be provided by depositing an annealing SiO2 / TiO2 multilayer structure filter.

Hereinafter, an embodiment of the present invention and its experimental results will be described in detail.

However, the following examples and experimental results are merely illustrative of the present invention, and the contents of the present invention are not limited to the following examples and experimental results.

< Example >

The multilayered SiO ₂ / TiO ₂ film was deposited on a 0.5 μm thick glass substrate by a cluster sputtering system. Prior to the deposition, the glass substrate was washed sequentially in acetone, alcohol and demineralized water for 15 minutes each by an ultrasonic bath. Subsequently, the substrate was moved to a cluster sputter chamber, and at the same time, an SiO2 / TiO2 stacking layer was deposited using high purity (99, 99%) TiO2 and SiO2 targets. The pure Ar (99.99%) gas flow rate and chamber pressure for both films were fixed at 120 sccm and 15 mTorr. Radio frequency sputtering powers of 250W and 300W were applied to TiO2 and SiO2 targets, respectively. The 74 nm thick TiO2 (n = 2.32) and 96 nm thick SiO2 (n = 1.45) layered films were deposited at 5.7 and 3.6 Pa / s deposition rates, respectively. The SiO2 cavity refractive index was chosen to be 1.44 with a layer thickness of 373 nm. Thereafter, the prepared multilayer film was annealed at a temperature of 300 ° C., 400 ° C. and 500 ° C. for 90 minutes in a box furnace under an oxygen atmosphere. The structural properties of the film were characterized by an X-ray diffractometer (Bruker, D2 PHASER, Cu Kα, λ = 0.15406 nm). Surface morphology, microstructure and optical properties were characterized by atomic microscopy (AFM, XE-100), scanning transmission electron microscopy (STEM) and UV-Vis spectroscopy (UV-Vis, Lambda 750), respectively. The binding properties and surface contamination of all samples were evaluated by Fourier transmittance infrared spectroscopy (FT-IR). Band-pass and color filter properties were measured by a PR-650 spectrometer.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. If the person having ordinary knowledge in the technical field to which the present invention pertains, the technical spirit of the present invention can be clearly understood through the above-described embodiments and drawings, and various forms may be modified within the scope of the technical spirit to which the present invention pertains. Can be.

<Experiment results>

The structural and morphological properties of the SiO2 / TiO2 multilayer film are shown in FIG. 1. 1 (a) shows the XRD pattern of the multilayer film before and after annealing. It can be seen that SiO 2 / TiO 2 deposited and low temperature annealed (300 ° C.) exhibits amorphous properties. By further raising the annealing temperature to 400 and 500 ° C., the anatase TiO2 diffraction planes of (101), (004), (200), (105) and (211) were 25.38 °, 38.07 °, 48.32 °, respectively. It began to appear at 54.17 ° and 55.32 °. The intensity of the (004) and (200) reflection peaks for the film annealed at 500 ° C was increased, indicating that the crystallinity was improved. The surface morphology AFM image of the multilayer film annealed at 500 ° C shows the granular structure with average particle size and roughness of 50 nm and 5 nm, respectively (see Fig. 1 (b)). To obtain more insight into the crystallography of the multilayer film, the microstructure and elemental composition were analyzed by HR-TEM and TEM-EDS techniques and are shown in FIGS. 1 (c)-(f). 1 (c)-(e) show cross-sectional bright field region TEM, HR-TEM and EDS element mapping images of samples annealed at 500 ° C. The TEM image of the brightfield region clearly shows that the entire film consists of a composite film with a total thickness of 1.185 μm, deposited alternately with 6 TiO 2 and 5 SiO 2 layers. FIG. 1 (d) shows the HR-TEM image of the boxed region of FIG. 1 (c), and the lattice streaks of 0.35 nm on the TiO2 (101) plane were in good agreement with the SRD results. The distribution of Si, Ti, and O elements in the total multilayer film is shown in the EDS mapping image in FIG. 1 (e). The line profile obtained along the X-Y line (shown in Figure 1 (f)) shows that the Si and Ti atomic percentages change 5% in the corresponding SiO2 and TiO2 layers throughout the composite film.

The optical transmittance, reflection and absorption properties of the SiO2 / TiO2 multilayer film before and after annealing at different temperatures were investigated in FIG. 2. The experimental results show filter characteristics through which blue wavelengths of about 450 nm or less, wavelengths around 560 nm, wavelengths around 750 nm, and wavelengths above 850 nm pass (see FIG. 2). As shown in Fig. 2 (a), the light transmittance of the sample simultaneously shows the blue shift due to the change in the annealing temperature with 80-95% transparency in the visible and infrared ranges (300-1600 nm). The room temperature transmittance for an annealed sample at 300-500 ° C. with a spectrum in the wavelength range of 300-500 nm shows three shoulder peaks centered around 382, 415 and 454 nm. The peak at 382 nm is ultraviolet and the other two peaks at 415 nm and 454 nm are related to the blue region in the measured spectral range. The blue and ultraviolet peaks at 454 nm (88%) and 382 (83%) show the highest transmittance values with a 5% difference. In the yellow region, very clear transmittance peaks were observed with transparency and peak centers of 78% and 568 nm, respectively. The transmittance in the infrared region, particularly at 907, 1065 and 1527 nm wavelengths, was at least 90%. Figure 2 (a) shows an enlarged image of the spectrum in the range of 520-620 nm to clearly show the blue shift of the transmittance according to the annealing temperature. It can be seen that when the annealing temperature is increased to 400 ° C., the spectrum becomes blue by 13 nm (568, 559, and 555 nm). However, if the annealing temperature is further increased to 500 ° C, a red shift occurs to 556 nm. The calculations indicate that as the annealing temperature increases, the FWHM of the spectrum decreases linearly as follows: 16.62 (568), 15.05 (559), 15.01 (555) and 14.27 (556) nm. The reason for the change in the transmittance of the multilayer film is due to the recrystallization of the TiO2 layer and the formation of a polycrystalline anatase phase of different refractive index.

The average reflectance values with response wavelengths at 382 and 454 nm are as low as 10% in the UV and blue regions and as high as 95% in the visible light range at 500-540 nm and 580-710 nm (see Figure 2 (b)). It showed the highest reflectance in the visible region of the sample annealed at 500 ° C, but decreased in the near infrared spectrum, especially at 790 and 1220 nm.

Figure 2 (c) shows the absorbance of the SiO2 / TiO2 multilayer film before and after annealing at temperatures of 300, 400 and 500 ° C. Absorbance shows two high intensity peaks in the visible spectrum at 526 and 638 nm. Thus, it can be concluded that green and red emission can be effectively absorbed by the filter. In contrast, the absorbance of the multilayer film in the UV-blue (300-500 nm) and near infrared (NIR) (750-1600 nm) spectrum is poor, so that the SiO2 / TiO2 multilayer film is effective UV-blue and near infrared band pass filters. To work.

2 (d) shows the FTIR spectrum results of films deposited and annealed at different temperatures, respectively. FTIR binding peaks were observed and designated as the proposed chemical species. The Si-O-Si characteristic bands at 800 and 1000- are due to symmetric and asymmetric tensile modes, respectively. The peaks at 3306 and 1633 cm ⁻¹ are due to stretching and bending vibrations of the OH group. The band around 1385 cm ^-1 is assigned to the Ti-O-Ti tensile mode, while the overlapping band in the 930 cm ^-1 region is related to the motion of the Ti-O-Si bond. Moreover, the presence of CO2 and CH binding peaks at 2364 and 2919 cm ^-1 was confirmed.

The color filtering properties of the multilayer film are shown in FIG. 3. Red, green and blue (RGB) light emitting diodes were selected as reference light sources, and the transmitted intensity for each wavelength was shown in FIGS. 3 (a)-(c). The red light emitting diode as a reference light source having a peak band center at 632 nm exhibited an intensity of 0.45 in unit value (Fig. 3 (a)). After the multi-layer film was used as a red-block filter, the intensity decreased rapidly to 0.02 units for the deposited film, and further decreased to 0.01 units when the annealing temperature reached 500 ° C. This means that 98% of the red transmittance was effectively blocked by the multilayer filter. The other 2% transmittance in red is due to the small gap between the 620-720 nm transmittance ranges in Figure 2 (a). The green color filtering by the multilayer film is shown in Figure 3 (b). For reference, the green LED shows the electroluminescent center at 535 nm and the intensity decreases from 0.084 to 0.015 units. A new peak at 568 nm was observed in the yellow region due to the sharp transmittance peak in the visible spectrum. And the peak was blue shifted from 568 to 560 and increased nonlinearly with increasing annealing temperature. Fig. 3 (c) shows the blue light filtration characteristics before and after annealing. Since the blue bandpass filter multilayer film delivers 98% blue emission, it works as shown in Figure 3 (c). The transmitted strength of the multilayer film is different from other colors, and is slightly reduced due to the effect of increasing the annealing temperature. The red, green and blue light emission intensities before and after filtering by the multilayer film at different temperatures are measured in cd / m ² and images obtained with a digital camera from the sample surface on the RGB-LED are shown in Fig. 3 (d).

That is, FIG. 3 shows a result of blocking a red light source having a center wavelength of about 635 nm, passing a blue wavelength centering at 460 nm, and a green light source having a center wavelength of 530 nm passing through a 560 nm center pass filter.

Through these experimental results, when the annealing was performed at 300 ° C, 400 ° C, or 500 ° C, and the multi-layered filter without annealing was compared, the multi-layered filter with annealing each LED light source at the specific temperature was used. It can be seen that the light source of a specific wavelength can be blocked or passed through more effectively if passed. Furthermore, it can be seen that by utilizing such a multi-layered filter, it is possible to increase the color purity of the LED light source by applying the wavelength band of the filter showing a narrow band pass characteristic to one of the red, green or blue LED light sources.

Claims (10)

a) cleaning the substrate sequentially with an ultrasonic bath in acetone, alcohol and demineralized water;
b) depositing a SiO2 / TiO2 stacking layer using SiO2 and TiO2 targets through a sputtering method;
c) controlling the color purity of the multilayer film by annealing the deposited multilayer film at a temperature of 300 to 500 ° C. for 60 to 120 minutes under an oxygen atmosphere;
Method of manufacturing a SiO2 / TiO2 multilayer structure filter comprising a.
According to claim 1,
The substrate of step a is a glass substrate, and the method of manufacturing the SiO2 / TiO2 multilayer structure filter is characterized by sequentially washing in acetone, alcohol and demineralized water for 10 to 20 minutes, respectively.
According to claim 1,
The step b is deposited under Ar gas, and the multilayer structure is a method of manufacturing a SiO 2 / TiO 2 multilayer structure filter, characterized in that it consists of 5 to 13 layers.
delete According to claim 1,
The SiO2 / TiO2 multilayer structure is a method of manufacturing a SiO2 / TiO2 multilayer structure filter, characterized in that a symmetrical structure is formed around a middle layer.
A liquid crystal display (LCD) comprising a SiO2 / TiO2 multilayer structure filter prepared according to the method of claim 1,
A liquid crystal display device comprising a substrate, a color filter, and an outer film, wherein the SiO2 / TiO2 multilayer structure filter is disposed between the substrate and the outer film.
An organic light emitting diode (OLED) display device including a SiO 2 / TiO 2 multilayer structure filter prepared according to the method of claim 1,
An organic light emitting device comprising an encapsulation layer, first and second electrode layers, a TFT layer, an OLED layer, a substrate, and an outer film, wherein the SiO2 / TiO2 multilayer structure filter is disposed between the substrate and the outer film. Diode display.
A light emitting diode display comprising an LC panel, a light guide plate, a reflector and a light emitting diode (LED),
A multilayer structure of SiO2 / TiO2 prepared according to the method of claim 1 between the LC panel, the light guide plate and the reflector, wherein the LC panel, the light guide plate and the reflector are stacked with each other, and including a light emitting diode (LED) on the side of the light guide plate. A light emitting diode display device comprising a filter.
A light emitting diode including a light emitting diode (LED) chip, an epoxy, a phosphor, and a lens,
A light emitting diode comprising a SiO2 / TiO2 multilayer structure filter manufactured according to the method of claim 1, between the light emitting diode chip and the epoxy or between the phosphor and the lens.
SiO2 in which annealing was performed at a temperature of 300 to 500 ° C. for 60 to 120 minutes under an oxygen atmosphere in a pre-process or a post-process step of a liquid crystal display (LCD) color filter, light emitting diode (LED), or organic light emitting diode (OLED) manufacturing process. / TiO2 A method of controlling the color purity of a liquid crystal display color filter, a light emitting diode or an organic light emitting diode by depositing a multilayer structure filter.

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