KR20040019177A - Method for manufacturing white light emitting diode - Google Patents

Abstract

PURPOSE: A method for fabricating a white LED(light emitting diode) is provided to obtain white light by exciting fluorescent materials of red, green and blue by ultraviolet rays and by mixing the fluorescent materials in a proper ratio. CONSTITUTION: A fluorescent material capable of generating red light, green light blue light due to a light source for generating ultraviolet rays is excited while at least one kink of fluorescent powder is used to reinforce the intensity of the spectrum of white light and to correct the constituents of the spectrum. A fluorescent material that can be excited by ultraviolet rays or visible rays is used as fluorescent powder for reinforcing or correcting the spectrum characteristic of the white light.

Description

Manufacturing method of white light emitting diode {METHOD FOR MANUFACTURING WHITE LIGHT EMITTING DIODE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a white light emitting diode, and more particularly, to a method for producing and obtaining a white light emitting diode by blending powders of various kinds of fluorescent properties.

White light is mixed synthetic light of a plurality of wavelength colors, and the light source identified by the human eye as white light includes mixed light rays of at least two kinds of wavelengths. For example, an LED light source that emits white light on the basis of such a principle, since it is felt as white light when the human eye is simultaneously stimulated by red, blue, and green light rays, or simultaneously by blue and yellow light rays. Can be prepared. There are five types of conventional white light LED manufacturing methods, and the first method uses three LEDs made of AlInGaP, GaP, and GaN, and controls the current passing through each LED to control red, green, and blue light. Emit light. Since these three crystal grains are arranged in the same lamp, the white light can be emitted by mixing the light beams that emit them through the lens. The second method uses two LEDs made of GaN and AlInGaP, and generates white light by emitting blue and yellow-green light rays by controlling the current through these LEDs. At present, these two types of light emitting efficiency can reach 20lm / W. The third method is a method of manufacturing a white light source by incorporating an yttrium aluminum garnet (YAG) fluorescent powder emitting yellow light into an indium gallium nitride blue light emitting diode developed by Nichia Chemical in Japan in 1996. Although the luminous efficiency of this method is slightly lower than that of the above type in the present case (can reach 15 lm / W or more), this white light source requires only a single color LED, which can greatly reduce the manufacturing cost, In addition, since the preparation technology of the fluorescent powder used in combination is already perfect, products are already on the market. The fourth way to generate white light is a white light LED using ZnSe material, developed in January 1999 by Sumitomo Electric Industries, Ltd. The technology first forms a CdZnSe thin film on a ZnSe single chip substrate. After the energization, the thin film emits blue light, emits yellow light by irradiating some blue light onto the substrate, and finally emits white light by complementing the blue light and yellow light. Since only one LED crystal grain is employed in this method, the operation voltage is only 2.7V, which is lower than 3.5V of the LED of InGaN, and white light can be obtained without a fluorescent substance. The fifth method for generating white light is an ultraviolet white light LED currently under development, that is, a method in the field of the present invention, and its principle is to excite three kinds of fluorescent powders by an ultraviolet LED to generate fluorescence, and to mix white light by white light. To generate, and the conventional method in the field is as follows.

1. Synthesis of Y ₂ O ₃ : Eu fluorescent powder, for example (Y _1.9 Eu _0.1 ) O ₃ , as a synthesis method, solid reaction method, chemical synthesis method, for example, citrate gel method or co-treatment Precipitation method, micro colloid method and the like can be employed.

2. Synthesized and obtained SrAl ₂ O ₄ : Eu fluorescent powder, for example, (Sr _0.96 Eu _0.04 ) Al ₂ O ₄ , and as the synthesis method, solid reaction method, chemical synthesis method, for example, citrate gel method or Precipitation method, micro colloid method and the like can be employed.

3. Synthesis of BaMgAl ₁₀ O ₁₇ : Eu-type fluorescent powder, for example, (Ba _0.9 Eu _0.1 ) MgAl ₁₀ O ₁₇ , and as the synthesis method, solid reaction method, chemical synthesis method, for example, citrate gel method or Precipitation method, micro colloid method and the like can be employed.

4. The above three kinds of fluorescent powders were prepared in a predetermined proportion, and the emission spectrum thereof was detected using ultraviolet rays having a wavelength of 396 nm as an excitation source, as shown in FIG. The emission spectrum data is converted into the chromaticity coordinates represented by the corresponding phosphors by the formula of the chromaticity diagram established by the Commission Internationale de 1 'Eclairage (CIE) in 1931. It is shown in FIG.

As can be seen from the above description, at present, a method of manufacturing a white light LED by an ultraviolet light emitting diode mainly excites phosphors of three primary colors of red, green, and blue by ultraviolet rays, and prepares the phosphors in an appropriate proportion, White light is acquired by mixing color light.

However, in the case of white light generated by combining the spectral constitutions of each of the primary color phosphors, since individual fluorescent powders are affected by having a predetermined spectral constitution, the distribution and continuity of the spectral wavelengths of the white light thus formed are actually Since it is less than the sunlight of the light, it has the faults, such as a color unevenness and low saturation to white light. The human eye can omit these phenomena so that only white light is visible, but when detected with a high-precision optical detector, for example by video or a camera, the color rendering is actually considered to be still low, i.e. Errors may occur in the case of color reduction, so that the white light source generated by this kind of method is simply suitable only for general lighting applications.

Therefore, the inventor of the present invention proceeds research and development, and adds academic work, and finally provides a method of manufacturing a white light emitting diode by incorporating powder having various kinds of fluorescent properties into the light emitting diode. The white light emitting diode has high luminance and high color rendering property.

The main object of the present invention is to propose a method of manufacturing a new white light emitting diode, and the characteristic of the method is that the phosphor of red, green by some of them using a phosphor that can be excited by various kinds of ultraviolet light The basic structure of the spectrum of three kinds of white light such as blue and blue is provided, and the color light for correction is provided by the phosphors of different parts, and the brightness thereof is improved, so that the degree of similarity between the mixed color spectrum of the phosphors and the spectrum of the actual sunlight. Significantly improves. Therefore, this invention has the outstanding point which can make high brightness and high color rendering property to the white light emitting diode acquired by the reinforcement and correction technique of various kinds of fluorescent powder.

Another object of the present invention is to provide a method of manufacturing a light emitting diode capable of discoloring light emission. At present, as a method for acquiring light-emitting diodes capable of changing the light color, a plurality of monochromatic light-emitting diodes are combined, and their light emission order is controlled by an electric circuit or light-colored by light filter pieces or hat covers of different complexion colors, respectively. Is converting. However, in the case of such a method, manufacturing cost is high and there is no convenience, and therefore, a new workable method needs to be developed. For example, by employing the techniques of reinforcement and modification of various kinds of fluorescent powders as described above, all or some of the powders have fluorescence or phosphorescence characteristics at the same time, and after stopping of excitation by ultraviolet rays, With the passage of time, the effect of changing the color of the light can be obtained, that is, in the case of the method of the present invention, it is possible to manufacture a discolorable light emitting diode. In addition, it is possible to provide a light emitting diode having a different discoloration order by changing the composition proportion of the powders. Compared with the prior art, the method of the present invention is quite simple, low in cost and high in industrial use.

1 is a white light spectrum in the case of emitting red, green, and blue fluorescence by three kinds of fluorescent powders, such as conventional Y ₂ O ₃ : Eu, SrAl ₂ O ₄ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, etc. An explanatory diagram showing

2 shows light emission of red, green, and blue fluorescence by three kinds of fluorescent powders of Y ₂ O ₃ : Eu, SrAl ₂ O ₄ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, and the like. ₃ Al ₅ O ₁₂ : An explanatory diagram showing a spectrum of white light emitted by combining yellow fluorescence emitted by Ce and Gd phosphors.

FIG. 3 is an explanatory diagram showing chromaticity coordinates A and B of the mixed fluorescent powders calculated and calculated on the basis of the emission spectra of FIGS. 1 and 2, respectively;

4 is a starting point of white light emitted by simultaneously mixing Y ₂ O ₃ : Eu, SrAl ₂ O ₄ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, Y ₃ Al ₅ O ₁₂ : Ce, Gd phosphors according to the present invention. Moreover, it is a change figure which shows the situation where the light color at the time of removing an ultraviolet-excitation light source changes with time.

EMBODIMENT OF THE INVENTION Below, the characteristic and technical content of this invention are described in detail, referring an accompanying drawing, It is to be said that these description is only a part of preferable embodiment of this invention, and does not narrowly define the scope of this invention. It is not necessary.

The present invention relates to a method of manufacturing a white light emitting diode using powders having various kinds of fluorescent properties, which are applied to light emitting diodes. This method uses a light emitting diode, an electron beam, or a plasma that can emit ultraviolet light as an excitation light source, and excites two types of fluorescent powders, red light having a wavelength of 585 nm to 640 nm, green light having a wavelength of 500 nm to 570 nm, and blue light having a wavelength of 430 nm to 490 nm, respectively. Emit light. At the same time, in consideration of the fluorescence properties of these three wavelengths, for example, the luminescence intensity, color saturation, etc., the fluorescence properties having the four or more wavelengths are supplemented or corrected by the fluorescence properties of the other one or more fluorescence powders. After mixing the white light is generated. White light obtained by the fluorescent reinforcement and correction technique of the present invention has an excellent point of having high luminance and high color rendering, as compared with the conventional method of simply using three primary colors of red, green and blue phosphors.

As one of the embodiments of the synthesis and preparation fluorescent powder required by the white light emitting diode of the present invention (one of the methods of the present invention, a method of representing the spectrum of white light obtained after modifying the spectral structure) Can be mentioned.

1. Synthesis of Y ₂ O ₃ : Eu fluorescent powder, for example, (Y _1.9 Eu _0.1 ) O ₃ , and as a synthesis method, solid reaction method, chemical synthesis method, for example, citrate gel method or co-precipitation method, The micro colloidal method etc. can be employ | adopted.

2. Synthesized and obtained SrAl ₂ O ₄ : Eu fluorescent powder, for example, (Sr _0.96 Eu _0.04 ) Al ₂ O ₄ , and as the synthesis method, solid reaction method, chemical synthesis method, for example, citrate gel method or Precipitation method, micro colloid method and the like can be employed.

3. Synthesis of BaMgAl ₁₀ O ₁₇ : Eu-type fluorescent powder, for example, (Ba _0.9 Eu _0.1 ) MgAl ₁₀ O ₁₇ , and as the synthesis method, solid reaction method, chemical synthesis method, for example, citrate gel method or Precipitation method, micro colloid method and the like can be employed.

4. The composition is obtained by synthesizing Y ₃ Al ₅ O ₁₂ : Ce, Gd-type fluorescent powder, for example, (Y _2.3 Ce _0.05 Gd _0.65 ) Al ₅ O ₁₂ , and using the solid reaction method or the chemical synthesis method, for example. For example, citrate gel method, co-precipitation method, micro colloid method and the like can be adopted.

5. The above four kinds of fluorescent powders were prepared in a predetermined proportion, and the emission spectrum thereof was detected using ultraviolet rays having a wavelength of 396 nm as an excitation source, as shown in FIG. The data of the emission spectrum is converted into chromaticity coordinates representing the mixed phosphor, and denoted in FIG. 3 by B point.

Moreover, this invention also relates to the manufacturing method of a 1 type of discolorable light emitting diode, Comprising: The light-emitting body which has phosphorescence characteristics is made into 1 type | mold or plural types of the said fluorescent substance, and the light color differs with time, respectively. It can represent a change. As these light emitters, SrAl ₂ O ₄ : Eu, M, CaAl ₂ O ₄ : Eu, M, Sr ₄ Al ₁₄ O ₂₅ : Eu, M, Y ₂ O ₂ S: Eu, M, ZnS: Cu, M, etc. Among them, a transition metal, a rare earth element, or the like can be employed as M.

Regarding one embodiment of the manufacturing of a discolorable light emitting diode manufactured by a powder having phosphorescent properties, the manufacturing steps thereof are as follows.

1. Synthesis of Y ₂ O ₃ : Eu fluorescent powder, for example, (Y _1.9 Eu _0.1 ) O ₃ , and as a synthesis method, solid reaction method, chemical synthesis method, for example, citrate gel method or co-precipitation method, The micro colloidal method etc. can be employ | adopted.

2. The composition of SrAl ₂ O ₄ : Eu, Dy type fluorescent powder, for example (Sr _0.94 Eu _0.04 Dy _0.02 ) Al ₂ O ₄ is synthesized and obtained as a solid reaction method or chemical synthesis method, for example Citrate gel method, co-precipitation method, micro colloid method, etc. can be employ | adopted.

3. Synthesis of BaMgAl ₁₀ O ₁₇ : Eu-type fluorescent powder, for example, (Ba _0.9 Eu _0.1 ) MgAl ₁₀ O ₁₇ , and as the synthesis method, solid reaction method, chemical synthesis method, for example, citrate gel method or Precipitation method, micro colloid method and the like can be employed.

4. The composition is obtained by synthesizing Y ₃ Al ₅ O ₁₂ : Ce, Gd-type fluorescent powder, for example, (Y _2.3 Ce _0.05 Gd _0.65 ) Al ₅ O ₁₂ , and using the solid reaction method or the chemical synthesis method, for example. For example, citrate gel method, co-precipitation method, micro colloid method and the like can be adopted.

5. The above four kinds of fluorescent powders are prepared by a predetermined proportion, and the emission spectrum thereof is detected using an ultraviolet ray having a wavelength of 396 nm as an excitation source. In addition, the ultraviolet excitation light source is removed, and its emission spectrum is detected several times at predetermined time intervals, and the data of these emission spectra are converted into chromaticity coordinates of respective time points, and gradually moved from point A to point B. And these are shown in FIG.

As shown below, when comparing the conventional method obtained by calculation with the white light spectrum of embodiment of this invention, it turns out that the color rendering and color temperature of this invention became much more preferable than before.

Conventional method Method of the invention CIE chromaticity coordinates (0.3130, 0.3254) (0.3120, 0.3285) Color rendering 85 94 Color temperature 6524K 6550K

1. As can be seen from Fig. 3, both the method of the present invention (see the embodiment) and the conventional method can acquire the effect that the chromaticity coordinates are located in the standard white light region, for example, (0.3130, 0.3245) and (0.3120, 0.3285) of the embodiment. Therefore, the white light diode of the present invention can provide a white light emitting diode as in the conventional method.

2. As shown in the table, in the case of the conventional method, white light composed of three primary colors of red, green, and blue is obtained by three kinds of fluorescent powders, the color rendering property is only 85, and the color temperature is 6524K (absolute temperature). )to be. In the case of the embodiment of the present invention, the spectral constitution can be corrected by Y ₃ Al ₅ O ₁₂ : Ce, Gd type yellow fluorescent powder to improve the color rendering property to 94 and the color temperature to 6550K. The main reason for this is that the distribution of the white light spectrum after the modification of the spectral structure and the spectrum of the actual sunlight is close, thereby obtaining high color rendering properties, and therefore, in the case of the white light emitting diode of the present invention, the color rendering properties are considerably superior to conventional methods. .

3. In the case of the white light emitting diode of the present invention, if the emission spectrum is corrected, for example, Y ₃ Al ₅ O ₁₂ : Ce, yellow light of a Ce, Gd-type fluorescent powder or BaMgAl ₁₀ O ₁₇ : Eu, Blue-green light of Mn-type fluorescent powders (related to the proportion of Eu / Mn in the fluorescent powder and the relative intensity of the emitted blue / green wavelengths, so that they also have the functions of modifying their own color and controlling the adjustment) The lamps are all closer to the wavelength of green light, i.e., the area is sensitive to the human eye, and they act to improve the intensity of the entire white light, so that the luminous efficiency of the white light emitting diode of the present invention is a conventional method. bang.

4. In the case of the white light emitting diode of the present invention, since (Sr _0.94 Eu _0.04 Dy _0.02 ) Al ₂ O ₄ in the mixed fluorescent powder has a green phosphorescence property, the excitation light source is removed. The light color of the powder becomes greener than white, and at the same time, it is possible to maintain a predetermined time. Similarly, when a powder having two or more kinds of phosphorescent properties is used, the conversion of the resulting light color becomes colorful and diverse. Therefore, when several kinds of powders are mixed in a predetermined proportion according to the method of the present invention, and when a UV light emitting diode having a predetermined wavelength (396 nm in this example) is used in combination as an excitation light source, further packaging is appropriate. In this case, when a predetermined current flows, when the powders to be mixed are stopped after being irradiated with ultraviolet rays, a light emitting diode capable of converting light colors can be obtained at any time.

The above-described embodiments of the present invention are merely specific examples of the present invention, and the gist of the present invention is not narrowly limited to these, and all three types of red light having 585 nm to 640 nm are simultaneously used. High brightness and high color rendering by means of combining the phosphor that can emit three primary colors such as green light of 500nm-570nm and blue light of 430nm-490nm with one or more other fluorescent powders to enhance and correct the white light spectrum All changes, modifications, and the like, which are carried out for the purpose of obtaining an excellent white light emitting diode capable of acquiring L, should fall within the claims of the present invention. The present invention also relates to a method of manufacturing a discolorable light emitting diode, and by using one or more components of phosphors having various phosphorescent properties, the color of the light can be changed in different colors over time. have.

Claims (8)

In the white light emitting diode, Exciting phosphors capable of generating red light, green light and blue light by means of a light source generating ultraviolet rays, and employing at least one fluorescent powder as a means for reinforcing intensity of the spectrum of white light and as a means for correcting constitution, provides high luminance and high color rendering properties ( A white light emitting diode is obtained, The manufacturing method of the white light emitting diode characterized by the above-mentioned. The method for manufacturing a white light emitting diode according to claim 1, wherein a fluorescent substance which can be excited by ultraviolet rays, visible rays, or the like is employed as a fluorescent powder for reinforcing or correcting the white light spectral characteristics. The method of claim 1, wherein as a fluorescent powder for enhancing or modifying the characteristics of the white light spectrum, the emission wavelength range is close to the wavelength of green light, for example, Y ₃ Al ₅ O ₁₂ : yellow green light of Ce, Gd-type fluorescent powder Or BaMgAl ₁₀ O ₁₇ : Eu, Mn type fluorescent powder blue green light is adopted, the manufacturing method of the white light emitting diode characterized by the above-mentioned. The method of claim 1, wherein the fluorescent powder can be produced and obtained by a solid reaction method, a chemical synthesis method, or the like, and can be produced and obtained by, for example, a citrate gel method, a coprecipitation method, a micro colloid method, or the like. Method for producing a white light emitting diode. The method of manufacturing a white light emitting diode according to claim 1, wherein a light emitting diode, an electron beam, a plasma, or the like can be employed as a light source capable of generating the ultraviolet rays. The method of claim 1, wherein a light emitter having a phosphorescent property is employed as one or more of the above-mentioned phosphors, so that the color of the light can be changed in different complexion colors over time. Method for producing a white light emitting diode. The method of manufacturing a white light emitting diode according to claim 6, wherein a light emitting body which can be excited by ultraviolet rays, visible light, or the like is employed as the light emitting body having the phosphorescence property. 7. The light emitting device according to claim 6, wherein SrAl ₂ O ₄ : Eu, M or CaAl ₂ O ₄ : Eu, M or Sr ₄ Al ₁₄ O ₂₅ : Eu, M or Y ₂ O ₂ S: Eu, M, ZnS: Cu, M, etc. can be employ | adopted, and among them, a transition metal, a rare earth element, etc. can be employ | adopted, The manufacturing method of the white light emitting diode characterized by the above-mentioned.