KR100797157B1 - White light-emitting inorganic-electroluminescents device, white light-emitting diode and illumination device using white phosphor layers - Google Patents

Abstract

The present invention provides an inorganic electroluminescent device having a white fluorescent film in which a blue fluorescent film, a green fluorescent film, and a red fluorescent film are arranged in one layer, or a white fluorescent film in which a complementary blue fluorescent film and a yellow fluorescent film are arranged in one layer. The present invention relates to a white light emitting device provided and a lighting device including the same, wherein the light emitting colors of the respective fluorescent films are mixed to emit white light. This minimizes the reduction in luminous efficiency due to the reabsorption of each emitted light due to the conventional vertically stacked and mixed dispersion fluorescent film structure, thereby providing a white light source having better brightness and efficiency than the conventional white light emitting device.

Single layer, stripe, square lattice, hexagonal lattice, electroluminescent element for white light emission, white light emitting device, lighting device

Description

WHITE LIGHT-EMITTING INORGANIC-ELECTROLUMINESCENTS DEVICE, WHITE LIGHT-EMITTING DIODE AND ILLUMINATION DEVICE USING WHITE PHOSPHOR LAYERS}

Figure 1a is a block diagram of the edge light type backlight using a conventional cold cathode fluorescent lamp.

Figure 1b is a block diagram of a direct type backlight using a conventional cold cathode fluorescent lamp.

Figure 2a is a block diagram of a conventional vertical stacked electroluminescent device.

Figure 2b is a block diagram of a conventional mixed dispersion electroluminescent device.

Figure 3a is a block diagram of a square lattice structure fluorescent film according to the present invention.

FIG. 3B is a schematic diagram illustrating adjusting a grid size in FIG. 3A; FIG.

Figure 4a is a block diagram of a hexagonal lattice structure fluorescent film according to the present invention.

FIG. 4B is a schematic diagram illustrating adjusting a grid size in FIG. 4A; FIG.

5A is a block diagram of a stripe structure fluorescent film according to the present invention;

Figure 5b is a block diagram showing the width adjustment in Figure 5a.

6 is a block diagram of a white electroluminescent device having a white fluorescent film according to the present invention.

7 is an electroluminescence spectrum when the fluorescent films of FIGS. 3A and 3B are provided in FIG. 6.

8 is an electroluminescence spectrum when the fluorescent films of FIGS. 5A and 5B are provided in FIG. 6.

9 is an electroluminescence spectrum of a fluorescent film of a square lattice structure, a fluorescent film of a stripe structure, and a blue and yellow 1: 3 square lattice structure fluorescent film.

10A is a block diagram of a white light emitting device having a white fluorescent film according to the present invention.

FIG. 10B is an enlarged view of the main portion of FIG. 10A; FIG.

Fig. 11 is a relative photoluminescence spectrum when the fluorescent film of Figs. 3A and 3B, the fluorescent film of Figs. 5A and 5B, and the conventional mixed dispersion fluorescent film in Figs. 10A and 10B are provided.

Fig. 11A is a photoluminescence image when the Figs. 3A and 3B are provided with Figs. 10A and 10B.

FIG. 11B is a CIE chromaticity coordinate system with the fluorescent films of FIGS. 3A and 3B in FIGS. 10A and 10B.

FIG. 11C is a photoluminescence image when the fluorescent film of FIGS. 5A and 5B is provided in FIGS. 10A and 10B.

FIG. 11D is a CIE chromaticity coordinate system when the fluorescent films are provided with FIGS. 5A and 5B in FIGS. 10A and 10B.

<Description of the symbols for the main parts of the drawings>

11: cold cathode fluorescent lamp

12: reflector

13: diffuser plate

14: light guide plate

15: reflector

21: antioxidant layer

22: back electrode layer

23: dielectric layer

24, 25, 26: blue, green, red fluorescent film

27: glass

28: fluorescent film of mixed dispersion structure

29: front electrode layer

100: white fluorescent film according to the present invention

110: fluorescent film of a square grid structure according to the present invention

120: fluorescent film of hexagonal lattice structure according to the present invention

130: fluorescent film of the striped structure according to the present invention

171: LED chip

172: Reflective Cup

173: Epoxy Dome Lens

The present invention provides an inorganic electroluminescent device having a white fluorescent film in which a blue fluorescent film, a green fluorescent film, and a red fluorescent film are arranged in one layer, or a white fluorescent film in which a complementary blue fluorescent film and a yellow fluorescent film are arranged in one layer. It relates to a white light emitting device provided and a lighting device having the same .

In general, a liquid crystal display (LCD) device has a liquid crystal positioned between a common electrode substrate of a thin film, an active element for adjusting an applied voltage, and an electrode substrate connected to an address line. Thus, when no voltage is applied, the light is aligned in a spiral manner and the incident light passes. When the voltage is applied, the liquid crystal molecules are vertically aligned in the direction of the electric field to block or obstruct the passage of incident light. The liquid crystal itself does not have a light emitting property, and only serves to pass or block incident light. Therefore, backlight illumination is essential to the LCD panel in order to implement image information display using the LCD principle. By using the backlight of the white light source, color information can be reproduced by each pixel or sub-pixel in which blue, green, and red filters are disposed in each pixel of the LCD. As mentioned, the backlight illuminated on the LCD panel for full color implementation is a white light source, and a high brightness backlight having a uniform intensity is essential to obtain a uniform image.

1A and 1B are a structure of a back light unit (BLU) that is generally used in an LCD panel, which is based on a Cold Cathode Fluorescent Lamp (CCFL) technology. The principle of cold cathode fluorescent lamps is based on the principle of traditional fluorescent lamps, also called hot cathode fluorescent lamps (HCFL). That is, CCFL is a kind of light emission method of gas discharge, and it is a principle that emits light by stimulating fluorescent material applied inside the lamp, and it is also called a conversion device that converts electrical energy into light energy. CCFL is optimal as a typical light source of LCD because it has low calorific value and low power consumption and provides high brightness white light.

In the drawings, the same reference numerals are used to designate the same components.

1A shows an edge-light CCFL backlight 10a. The light emitted from the fluorescent lamp is directly incident on the light guide plate and light incident on the light guide plate 14 after being reflected by the reflector plates 12 and 15. Since the incident light is a line light source, the light guide plate 14 is used to convert the surface light into surface light, thereby realizing uniform surface light. In addition, the diffused light must be refracted and collected by using a vertical horizontal prism sheet, and the light emitted from the light guide plate is diffused using the diffuser plate 13.

FIG. 1B is a direct-type CCFL backlight 10b, in which a plurality of fluorescent lamps 11 are arranged on the rear surface of the diffuser plate 13 at regular intervals to reflect light emitted from the fluorescent lamps 11 to the reflecting plates 12 and 15. Thus, light is refracted and diffused through the prism sheet and the diffusion plate 13. The edge light method is preferred because of its thin thickness and low power consumption.

However, in the backlight unit manufactured through such a design, the luminous efficiency is drastically reduced in the process of converting the line light source to the surface light source. The light transmission efficiency of the prism sheet is 57.3%, and the light emission efficiency at the viewing surface that has passed through the LCD panel is only 5-7% of the backlight light source (CCFL). In addition, the design and process for manufacturing a thin panel of less than 2mm has the disadvantage that the manufacturing cost is expensive.

Backlight technology based on cold cathode fluorescent lamp (CCFL) technology has been accelerating price cuts in the last two to three years due to intense competition with other devices and increased demand in the LCD market. Therefore, the backlight based on the CCFL technology requires more than 80% of the manufacturing price compared to the selling price, so the reduction of the manufacturing cost is urgently required. However, the conventional BLU technology has a limitation in manufacturing cost reduction due to the labor-intensive manual manufacturing process and the need for a number of inverters, thereby accelerating the transfer of production bases to China. In addition, since mercury regulations have been in full swing since 2006, next-generation backlight technologies that can replace CCFLs are required.

Therefore, in order to overcome the shortcomings of the backlight based on the CCFL technology, a backlight technology using a white light emitting diode capable of surface emission and a white light emitting diode having high brightness characteristics has been studied.

Generally, photoluminescence, electroluminescence, and catholuminescence are classified according to the form of external energy absorbed by the phosphor. Photoluminescence is a phenomenon in which light is emitted to a fluorescent film to induce luminescence. The energy of incident light excites particles, and the energy absorbed by the fluorescent film passes through some other paths and is emitted as light by the remaining gap.

In other words, photoluminescence refers to a phenomenon in which atoms or molecules of a substance absorb light rays, ultraviolet rays, X-rays, and the like, and emit light by emitting photons having a wavelength longer than that of the absorbed photons. At this time, according to Stokes' law, the wavelength of the emitted photons is always longer than the wavelength of the incident photons. Therefore, the fluorescent film emits light mainly using light emitting short wavelengths of ultraviolet wavelength such as UV lamp as excitation energy source. Fluorescent lamps, fluorescent mercury lamps, luminous paints and the like are examples.

As such, photoluminescence emits energy using light, whereas electroluminescence emits light energy by applying an electric field to the fluorescent film.

That is, the electroluminescent device is an active solid display device that emits light by electroluminescence (EL) phenomenon in which a material emits light when an electric field is applied. Since it was discovered by O.W.Destriau in 1936, it has been actively applied to specific fields such as lighting and backlight sources, but its use is extremely limited due to problems in brightness and lifetime. That is, in spite of the advantages of uniform surface emission and easy manufacturing process, high voltage is required for low luminance and driving, and there is a problem of accelerating deterioration of image quality due to short lifetime of the blue light emitting material.

2A and 2B illustrate a method of implementing a white light source using a conventional electroluminescent device.

FIG. 2A shows a vertically stacked electroluminescent device consisting of an anti-oxidation layer 21, a back electrode layer 22, a dielectric layer 23, blue, green and red fluorescent films 24, 25, 26 and glass 27. It is a block diagram of 20a). A vertically stacked electroluminescent device 20a is illustrated in which blue, green, and red fluorescent films are sequentially stacked 24, 25, and 26, and then white voltage is applied to each fluorescent film individually. The vertical stacked electroluminescent device 20a has a limitation in that respective voltages must be applied to the blue, green, and red fluorescent films. In addition, the blue light emitted from the blue phosphor film is reabsorbed by the green and red phosphors, and the green light emitted from the green phosphor film is resorbed by the red phosphors.

2B shows a mixture consisting of an anti-oxidation layer 21, a back electrode layer 22, a dielectric layer 23, a fluorescent film 28 composed of mixed blue, green, and red phosphors, a front electrode layer 29, and a glass 27. It is a block diagram of the distributed electroluminescent element 20b. A mixed dispersion type electroluminescent device 20b is illustrated in which blue, green, and red phosphors are mixed with an organic binder and then dispersed between a single electrode to apply an alternating voltage to implement white light. There is an advantage of the single electrode, and the front emission layer is improved by reflecting light emitted from the back electrode to the front electrode layer. However, the blue and green light emitted from the blue and green phosphor films were reabsorbed by the green and red phosphors, and thus the fundamental limitations of the luminous efficiency were not overcome.

In addition, the white light emitting device for overcoming the disadvantages of the backlight based on the CCFL technology is a method of implementing the conventional white light, first, the yellow YAG-based phosphor is mixed with the epoxy and dispersed on the upper surface of the blue light emitting diode. After that, a high luminance blue light emitting diode in the wavelength range of 450 to 470 nm was used as an excitation energy source of a yellow phosphor, thereby realizing white color through the hue sum of the blue light of the light emitting diode and the yellow light of the phosphor. Alternatively, a method of obtaining white light using a light emitting diode having light emission characteristics in the ultraviolet wavelength range as an excitation energy source of three colors of blue, green and red phosphors was used. However, the white light reproduction using the white light emitting diode method, despite the advantages of having high brightness and long life, there is a problem that the manufacturing cost is expensive and severe heat generation. In addition, high brightness white light can be realized only by combining a high output light emitting diode and a phosphor having high luminous efficiency and color rendering property. In addition, there is a problem in that light emission luminance is irregular due to thermal instability of an epoxy resin and a silicone resin used to disperse a phosphor on an upper surface of the light emitting diode and an irregular distribution of the phosphor during curing, and color reproduction is poor.

In addition, the present invention can be widely applied as a lighting device in addition to the white light emitting device and the white light emitting device. That is, it can be used not only as a display device such as an LCD backlight, but also as a general lighting and an interior lighting device as a decorative meaning. Therefore, for those who want an efficient and energy-saving luminaire capable of producing a variety of colors, the development of a luminaire having a long lifespan and high luminance and color rendering will be a big challenge. .

Accordingly, an object of the present invention is to provide a high brightness, high efficiency white fluorescent film that can overcome the above problems, and an inorganic electroluminescent device, a white light emitting device, and a lighting device for white light emission using the same. In other words, cross-arrangement of the phosphors in a single layer minimizes the emission loss through reabsorption of the light emitted from each phosphor, thereby reproducing high-efficiency white light, and adjusting chromaticity by adjusting the grid size and stripe width of the arranged phosphors. It is an object of the present invention to provide a high luminance white fluorescent film close to a standard white light source.

In the inorganic electroluminescent device according to the present invention for achieving the above technical problem, a white fluorescent film or a complementary blue fluorescent film and a yellow fluorescent film in which a blue fluorescent film, a green fluorescent film and a red fluorescent film are arranged in one layer. The inorganic electroluminescent device having the white fluorescent film arranged in a row is driven by a single electrode, and the emission colors of the respective fluorescent films are mixed to emit white light.
In addition, a white light emitting device that emits light by using light emitted from a light emitting diode chip located inside a reflecting cup according to the present invention as an excitation energy source of a phosphor may include a blue fluorescent film, a green fluorescent film, and a red light on the light emitting diode chip. A white fluorescent film having a fluorescent film arranged in one layer or a blue fluorescent film having a complementary color and a white fluorescent film having a yellow fluorescent film arranged in one layer is provided, and the emission colors of the respective fluorescent films are mixed to emit white light.
Preferably, the light emitting diode chip uses a white fluorescent film, which emits light in the region of 340 nm to 470 nm.
Preferably, the inside of the reflective cup on which the fluorescent film is formed is molded with an epoxy resin or covered with a cavity to cover the light emitting diode chip.
The lighting apparatus according to the present invention includes a white fluorescent film in which a blue fluorescent film, a green fluorescent film and a red fluorescent film are arranged in one layer, or a white fluorescent film in which a complementary blue fluorescent film and a yellow fluorescent film are arranged in one layer. And emit light using an external energy source capable of exciting the respective fluorescent films.
Preferably, each of the fluorescent film uses a white fluorescent film, characterized in that the cross-arranged in a lattice structure or a stripe structure.
Preferably, each of the fluorescent film gratings is divided into different sizes or the width of each of the fluorescent film stripes is adjusted to adjust the chromaticity through the combination of each of the fluorescent film emission colors.

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Hereinafter, a white fluorescent film according to the present invention and a manufacturing method thereof, in particular, a manufacturing method using a screen printing method and a sputtering method, an electroluminescent device for emitting white light, a white light emitting device and a lighting device using the same will be described in order.

First, the white fluorescent film according to the present invention is formed by cross-aligning blue, green and red or complementary blue and yellow phosphors in a lattice structure (square lattice, hexagonal lattice, etc.) or stripe structure on a substrate. Thus, the respective phosphor colors are mixed to emit white light.

Then, a method of manufacturing the fluorescent film of the present invention will be described. Hereinafter, a process of manufacturing a fluorescent film by using a screen printing method and a sputtering method will be described.

First, the manufacturing process of the white fluorescent film using the screen printing method,

First, the fluorescent powder and the resin are mixed in the following ratio to prepare a phosphor paste. The ratio of red fluorescent powder (ZnS: Mn) and resin is 45: 55, the ratio of green fluorescent powder (ZnS: Cu, Al) and resin is 40: 60, and the blue fluorescent powder (ZnS: Cu, Cl) and resin is 55: 45 Mix in a Homo Mixer. At this time, by adjusting the mixing rate is prepared to uniformly disperse the powder, it is preferable to remove the oxygen in the vacuum chamber after mixing. In this case, the phosphor paste may use blue and yellow phosphors having two complementary color characteristics instead of the three primary phosphors. The blue phosphor powder (ZnS: Cu, Cl) and the yellow phosphor powder (ZnS: Mn) may be respectively used as a resin. Mix in a ratio of 35:65. This allows for easier mask making and allows for expansion of the white blend region. Each phosphor paste mixed with the resin is aligned with a mask of a 30 μm film formed in a lattice structure, and then a fluorescent film is formed as a single layer by screen printing sequentially using a squeezer. At this time, the fluorescent film means a phosphor paste film formed on a substrate. That is, for example, blue, green, and red phosphor pastes are arranged in one layer on the substrate to form a blue phosphor, a green phosphor, and a red phosphor. Each of the phosphors is arranged in one layer on the substrate. To form a white fluorescent film according to the present invention
At this time, it is preferable to make the entire surface to be printed in a uniform amount in order to achieve a surface light emission having a uniform intensity, each step of screen printing is maintained at 90 ℃ in the drying oven and dried for 15 minutes. In this case, the fluorescent film may be manufactured by aligning a mask formed of a stripe structure instead of the lattice structure.

The fluorescent film formed through the above-described fluorescent film manufacturing process is as shown in FIGS. 3A, 3B, 4A, 4B, 5A, and 5B.

3A illustrates a fluorescent film 110 having a square lattice structure according to the present invention. Blue, green, and red fluorescent films are alternately arranged in a square lattice structure. 3B illustrates chromaticity adjustment by adjusting the lattice size of each fluorescent film . That is, the phosphor emission color is adjusted by adjusting the four side lengths w _1, w _2, w _{3, and} w ₄ of each fluorescent film forming a square lattice. For example, when the two rectangular grids are arranged to abut from side to side, the right side w ₃ of the left square grating and the left side w ₁ of the right square grating come into contact with each other to have the same length, or to be brought up and down. In the two arranged square grids, the lower side w ₂ of the upper square lattice and the upper side w ₄ of the lower square lattice are in contact with each other, and thus have the same length. The reason for the same length is that in the two rectangular lattices which are in contact with the left and right sides, the upper right lattice point of the left rectangular lattice meets the upper left lattice point of the right rectangular lattice, and the lower right lattice point of the left rectangular lattice The lower left lattice point of the right square lattice meets, and at the two square lattices which are in contact with each other up and down, the lower lattice point of the upper square lattice meets the upper lattice point of the lower square lattice, and the upper square lattice This is because the lower left lattice point of X and the upper left lattice point of the lower rectangular lattice meet.
In this way, the length of the four sides of each lattice can be freely adjusted to adjust the desired emission color. In order to expand the color mixing region and reduce the amount of heat generated _, it is preferable to fabricate the dot size (w _1, w _2, w _3, w ₄ ) of the mask having a square lattice structure to 0.35 mm or less. In addition, blue, green, and red fluorescent films as illustrated, as well as complementary blue and yellow fluorescent films may be alternately arranged to produce a square grid structure fluorescent film.

4A illustrates a fluorescent film 120 having a hexagonal lattice structure according to the present invention. Blue, green, and red fluorescent films are alternately arranged in a hexagonal lattice structure. 4b illustrates that chromaticity is adjusted by adjusting the lattice size of each fluorescent film . That is, the phosphor emission color is adjusted by adjusting the lengths (w _1, w _2, w _3, w _4, w _{5, and} w ₆ ) of the six sides of each fluorescent film forming the hexagonal grid. For example, when adjusting the length of each side of two hexagonal lattice abutted left and right, the length of one w ₁ and the other w ₄ will be abutted to be the same length. Also, the length of one w ₃ and the other w ₆ will abut and be the same length. The reason is the same as described for the square lattice. In this way, the length of the six sides of each lattice can be freely adjusted to adjust the desired emission color. In order to expand the color mixing region and reduce the amount of heat generated _, it is preferable to fabricate the _half- dot size (w _1, w _2, w _3, w _4, w _5, w ₆ ) of the mask having a hexagonal grid structure of 0.3 mm or less. Do. In this case, a fluorescent film having a hexagonal lattice structure can be manufactured by alternately arranging complementary blue and yellow fluorescent films .

5A illustrates a fluorescent film 130 having a stripe structure according to the present invention. Blue, green and red fluorescent films are alternately arranged in a stripe structure. 5B illustrates chromaticity adjustment by adjusting the stripe width of each fluorescent film . In other words, each phosphor emission color is adjusted by adjusting the width w _{1 of the} stripe structure. In order to expand the color mixing region and reduce the amount of heat generated, it is preferable that the halftone size (w ₁ ) of the mask having the stripe structure be made 0.25 mm or less. In addition, it is also possible to produce a fluorescent film having a striped structure by alternately arranging complementary blue and yellow fluorescent films .

The fluorescent film of the above-described lattice structure and stripe structure can be adjusted in chromaticity by adjusting the size and width in addition to the illustrated configuration.

In addition, the structure of the fluorescent film formed on the single layer is characterized in that it can be applied to various modifications to the structure of the fluorescent film within a range not departing from the technical idea in addition to the square grid, hexagonal grid, stripe and the like.

Next, look at the manufacturing by the sputtering method which is another method for producing a white fluorescent film of the present invention. Hereinafter, the manufacturing process is demonstrated concretely.

First, a transparent base material (ITO or transparent glass) is installed inside the vacuum container of the sputter, and then the vacuum container is sufficiently evacuated and argon, oxygen, and hydrogen sulfide are supplied. At the same time, the temperature of the base material is raised and a frequency power (RF Power) is operated to form a plasma. In addition, three targets are made by sintering the blue, green and red phosphor powders mixed with the above-described fluorescent powder components. Here, the mask having the lattice structure or the stripe structure is aligned, followed by a two-step process of sequentially forming a thin film on the transparent base material by sputtering the three targets. Alternatively, complementary blue and yellow powders are sintered and sputtered sequentially. The deposited fluorescent film is subjected to a three step process of crystallizing at 700 ° C. The four-step process of determining the crystallinity and homogeneity of the thin film by analyzing the structure and surface state of the fluorescent film that has undergone the above-described process using a distributed X-ray diffractometer and a scanning electron microscope (SEM) Go through The thin film fluorescent film thus manufactured has excellent durability and thermal characteristics.

As described above, each of the fluorescent films composed of the phosphor paste deposited on the transparent base material may be formed in a structure such as a square grid, a stripe, a hexagonal grid, or the like. In addition to the deposition by the sputtering method, various vacuum deposition methods possible may be utilized.

Hereinafter, the electroluminescent device for high efficiency white light emission, in which the white fluorescent film of the present invention manufactured as described above is applied to the electroluminescent device, will be described in more detail with reference to Examples.

Example  1: for white light emission having a white fluorescent film of the present invention Electroluminescence  device.

Looking at the configuration of the electroluminescent device for white light emitting of high efficiency shown in Figure 6,

A glass substrate 24 that is transparent to light, excellent in heat shielding, and easy to make a large area at low cost, and an ITO (Indium Tin Oxide: InO + SnO) film having excellent light permeability and conductivity on the rear surface of the glass substrate 24 It is applied to the front electrode layer 29. A fluorescent film 100 manufactured by using the above-described fluorescent film manufacturing method is formed on the rear surface of the front electrode layer 29, and electroluminescence of the fluorescent material is performed on the rear surface of the fluorescent film 100 with a high dielectric constant characteristic with a thickness of 15 μm. At the same time, a dielectric layer 23 is formed which is transparent to emitted light. A back electrode layer 22 made of metal paste (Ag paste) having excellent reflection characteristics is formed on the back surface of the dielectric layer 23 to reflect light emitted backward from the fluorescent film. In this case, the rear electrode layer 22 is made of a metal paste having a reflection characteristic of 90% or more to realize high luminance white electroluminescence, thereby reflecting light propagated in the rear electrode direction to the front electrode layer to further increase luminous efficiency. The anti-oxidation layer 21 for protecting the back electrode layer is sequentially screen printed on the back surface of the back electrode layer 22 to produce a vertically stacked structure as a whole. Each paste is preferably prepared by maintaining at 90 ° C. and drying for 15 minutes in a drying oven. In addition, the electroluminescent device may be manufactured using a phosphor having two complementary color characteristics rather than a trichromatic phosphor. The electroluminescent device applies a voltage of 110V to 220V at both ends of the front electrode layer 29 and the back electrode layer 22 to induce an electric field in a fluorescent layer formed of a single layer lattice structure or a stripe structure, thereby causing the phosphor to emit light. Is operated.

7 illustrates electroluminescence (EL) spectra when a voltage of 110 V / 60 Hz is applied to a fluorescent film of a square lattice structure according to the present invention. It has an intensity of 0.00005a.u.highest point 141a at 470-530nm wavelength and an intensity of 0.00003a.u.highest point 141b at 560-600nm wavelength. Looking at the emission spectrum of the fluorescent film, it can be seen that strong absorption occurs in both the blue, green, and red regions.

8 shows electroluminescence (EL) spectra when a voltage of 110 V / 60 Hz is applied to the fluorescent film of the stripe structure according to the present invention. It has an intensity of 0.00006a.u.highest point 151a at 470-530nm wavelength and an intensity of 0.00004a.u.highest point 151b at 560-600nm wavelength. Again, looking at the emission spectrum of the fluorescent film, it can be seen that strong absorption occurs in both the blue, green, and red regions.

FIG. 9 illustrates electroluminescence (EL) spectra of a stripe structure fluorescent film, a square lattice structure fluorescent film, and a blue and yellow 1: 3 square lattice structure fluorescent film including FIGS. 7 and 8. The spectrum of the stripe structure and the square lattice structure fluorescent film is as described above, and the blue and yellow fluorescent film of the 1: 3 square lattice structure has a low intensity as a whole and is 0.00001a.u. The highest point 161 is shown.

Next, the high efficiency white light-emitting device which applied the white fluorescent film of this invention to the white light-emitting device which used UV light emitting diode as excitation light is demonstrated in detail through an Example. First, the light emission characteristics of the electroluminescent device and the white light emitting device will be briefly compared through a table.

Table 1 below shows the emission characteristics of the electroluminescent device using 110V / 60Hz to 220V / 60Hz as an energy source and the white light emitting device using the 365nm UV light emitting diode as an energy source.

TABLE 1

Luminescent Characteristics of Power Supply EL and UV Lamp PL

Power Supply EL image UV Light Emitting Diode PL Image 110V / 60Hz ~ 220V / 60Hz 365nm UV Phosphor Luminance Difference with Voltage Phosphor homogeneous luminous light emitting layer pin hole Color mixing glass Dielectric layer O₂ remaining

In addition, the chromaticity coordinates of the electroluminescent element and the white light emitting device will be described. First, the chromaticity coordinate is x = X / (X + Y + Z), y when three colors of blue, green, and red emitted from each phosphor mixture paste are used as the primary colors, and the primary colors are combined by X, Y, and Z. It is represented by the x, y, and z values obtained by = Y / (X + Y + Z) and z = Z / (X + Y + Z). In general, all colors are represented by (x, y) and theoretical pure white has chromaticity coordinates of (0.333, 0.333) in CIE chromaticity coordinates.

The table below shows the CIE chromaticity coordinates for each structure.

TABLE 2

Square grid, stripe, CIE chromaticity coordinates of 1: 3 square grid

structure CIE (x, y) CIE (x, y) Efficiency 110V / 60Hz Stripe 0.30, 0.41 When using diffuser plate 0.34, 0.43 30 to 45 percent reduction Square grid 0.29, 0.41 0.33, 0.43 1: 3 grid 0.38, 0.43 0.34, 0.43 UV light emitting diode Stripe 0.35, 0.38 0.33, 0.34 Square grid 0.37, 0.38 0.35, 0.38 1: 3 grid 0.40, 0.44 0.37, 0.40

As shown in the table, chromaticity coordinates at the time of emission of the electroluminescent element using 110V / 60Hz and the white light emitting device using the UV light emitting diode were shown. It was found that the white light emitting device using the UV light emitting diode showed higher luminance, and in each fluorescent film structure, the stripe structure showed the brightness closest to pure white. In addition, when the diffusion plate is used, the overall luminous efficiency decreases by about 30 to 45%.

Hereinafter, a high efficiency white light emitting device combining the fluorescent film and a light emitting diode and a method of manufacturing the same will be described.

Example  2: white light emitting device having a white fluorescent film of the present invention

10A and 10B illustrate the high efficiency white light emitting device 170 in which the fluorescent film 100 is combined with the light emitting diode chip 171 in the above embodiment. The inside of the reflective cup 172 may be molded with an epoxy resin or the like, or placed in a cavity state, and the fluorescent film 100 may be bonded to the top of the reflective cup 172. The epoxy dome lens 173 is enclosed in its circumference and finished. After phosphors having absorption characteristics in the near ultraviolet and blue regions are mixed with an organic binding resin, a fluorescent film is manufactured by screen printing or sputtering on a transparent glass substrate using a lattice structure or a stripe structure. The fluorescent film is bonded to the top of the InGaN-based light emitting diode having light emission characteristics in the near ultraviolet and blue (340 to 470 nm) regions. Thus, a white light emitting device is manufactured in which the fluorescent film emits light by a light emitting diode chip to realize high efficiency white light by mixing light emission colors of respective phosphors.

However, the present invention is not characterized by the internal structure of the white light emitting device, and FIGS. 10A and 10B are merely examples of the white fluorescent film according to the present invention, and may be applied to white light emitting devices having various structures. Of course.

FIG. 11 is a relative light emission spectrum of the white light emitting device having the white fluorescent film produced by the present invention in FIG. 10A and the light emission spectrum of the white light emitting device having the conventional mixed dispersion type fluorescent film.

The emission efficiency and luminance were compared with the photoluminescence spectrum according to the structure of the fluorescent film bonded to the top of the reflecting cup using the 365 nm UV light emitting diode as the excitation light.

Looking at the graph, the photoluminescence spectrum of a conventional white light emitting device having a mixed dispersion fluorescent film is 0.000175a.u. At a wavelength of 380 ~ 420nm. The highest point of accuracy is shown, and the highest point of 0.000125a.u. Is shown at a wavelength of 490-510 nm. On the other hand, the photoluminescence spectrum of the white light emitting device having the fluorescent film of the square lattice structure of the present invention is 0.00021a.u. The highest point of accuracy is shown, and the highest point of 0.00017a.u. Is shown at a wavelength of 490-510 nm. Further, the photoluminescence spectrum of the white light-emitting device having the fluorescent film of the stripe structure of the present invention is 0.000273a.u. At a wavelength of 380-420 nm. It shows the highest point of accuracy and is 0.0002a.u. At a wavelength of 490-510 nm. It represents the highest point of the degree. Accordingly, it can be seen that the light emission luminance is improved by about 22% or more in the square lattice structure and about 53% or more in the stripe structure.

In addition, the highest point in the wavelength range of 380 ~ 400nm rises by more than 50% to minimize the re-absorption of blue light to maximize the luminous efficiency and the brightness is also greatly increased.

FIG. 11A illustrates a photoluminescence (PL) image when a fluorescent film having a square lattice structure is used. It can be seen that the brightness is very bright.

FIG. 11B shows that a white light emitting device using a rectangular lattice-shaped fluorescent film has color coordinates x = 0.37 and y = 0.38 (indicated by ●), indicating that luminance is very close to theoretical white coordinates x = 0.333 and y = 0.333. Able to know.

FIG. 11C shows a photoluminescence (PL) image when a stripe structure fluorescent film is used. It can be seen that the brightness is very bright.

FIG. 11D shows that a white light emitting device using a fluorescent film having a striped structure has color coordinates x = 0.35 and y = 0.38 (indicated by ●), and shows that luminance is very close to theoretical white coordinates x = 0.333 and y = 0.333. have.

In addition, the white fluorescent film of the present invention can be provided in a lighting apparatus, and white light can be realized using various external energy sources capable of exciting each phosphor. For example, the present invention is applied to a fluorescent lamp using a low pressure discharge principle, and the ultraviolet rays generated by the discharge stimulate the fluorescent film provided inside the glass tube, or apply to the high pressure sodium discharge lamp to excite the light emitted from the sodium. It emits light by using it as an energy source. Such lighting fixtures may be applied to various applications from general home lighting to street lamps and store display lighting.

As described above, the white fluorescent film of the present invention can be applied to various fields such as an electroluminescent device, a white light emitting device, and a white lighting device.

The present invention is not limited to the above embodiments, and various modifications are possible without departing from the scope of the technical idea of the present invention. Therefore, the scope of the present invention should not be limited to the examples, but should be defined by the claims and the equivalents described below.

 The white fluorescent film according to the present invention configured as described above has an effect of overcoming a decrease in luminous efficiency due to reabsorption of respective phosphor emission light according to a conventional vertically stacked and mixed dispersion fluorescent film structure, which is arranged in a single layer. .

In addition, the chromaticity can be adjusted by variously adjusting the lattice size and width of the cross-arrayed lattice structure and the stripe structure fluorescent film, so that it is very easy to mix and reproduce desired colors.

In addition, when the white fluorescent film according to the present invention is applied to the electroluminescent device, it can be driven by a single electrode to reduce the power consumption, and has the effect of emitting a white light of high luminance close to the standard white light source.

In other words, in the surface light source, which is a key part of the LCD backlight development, it can overcome the fundamental problems of the LCD backlight technology using the EL, which is a representative surface light source, and can have a great competitiveness in the LCD market.

In addition, the white light emitting device and the lighting device having the white fluorescent film according to the present invention can emit white light with higher luminance and higher efficiency than the conventional one, and can be replaced according to the mercury regulations in 2006 and the LCD backlight which can meet the increasing demand of the LCD market. There is an effect that can be used in a variety of applications in a wide range of applications, such as the use as possible white light.

For reference, the present invention was awarded at the 4th National University Invention Club Contest organized by the Korea Intellectual Property Office and hosted by the Korea Invention Promotion Association, held in Daejeon International Patent Training Department on August 22-24, and won the Gold Prize Award from the President of the Patent Office. Has proved its excellence.

Claims (12)

delete delete delete A white light emitting device that emits light by using light emitted from a light emitting diode chip located inside a reflecting cup as an excitation energy source of a phosphor, On the light emitting diode chip, a white fluorescent film in which a blue fluorescent film, a green fluorescent film and a red fluorescent film are arranged in one layer or a white fluorescent film in which a complementary blue fluorescent film and a yellow fluorescent film are arranged in one layer is provided. A white light emitting device using a white fluorescent film, characterized in that the emission color of each fluorescent film is mixed to give white light. The method of claim 4, wherein Wherein each of the fluorescent films is cross-arranged in a lattice structure or a stripe structure. The method of claim 5, And dividing the respective fluorescent film gratings into different sizes or adjusting the width of each fluorescent film stripe to adjust chromaticity through the combination of the fluorescent film emitting colors. The method of claim 4, wherein The light emitting diode chip is a white light emitting device using a white fluorescent film, characterized in that for emitting light in the region of 340 nm to 470 nm. The method of claim 4, wherein The inside of the reflective cup on which the fluorescent film is formed is molded with an epoxy resin to cover the light emitting diode chip, or is in a cavity state, the white light emitting device using a white fluorescent film. In the lighting device, A white fluorescent film in which a blue fluorescent film, a green fluorescent film and a red fluorescent film are arranged in one layer, or a white fluorescent film in which a complementary blue fluorescent film and a yellow fluorescent film are arranged in one layer may be provided to excite each of the fluorescent films. Lighting device using a white fluorescent film, characterized in that for emitting light using an external energy source. The method of claim 9, Wherein each of the fluorescent films is cross-arranged in a lattice structure or a stripe structure. The method of claim 9, And dividing each of the fluorescent film gratings into different sizes or adjusting the width of each fluorescent film stripe to adjust chromaticity through the combination of each of the fluorescent film emission colors. delete

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