KR100457864B1 - Phosphor for white LED lamp - Google Patents

Abstract

The present invention is Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [which is excited in a broad wavelength region of ultraviolet and violet to emit white light. x = 0-7), y, z, w].

The phosphor Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z, w] has an excitation wavelength It is distributed in a wide range from 250 nm to 430 nm, so that a conventional nitride semiconductor can be used as excitation light, and the emission spectrum exhibits uniform white light from blue to red. In addition, it is possible to implement a variety of colors according to the change in the composition ratio x, y, z, w of each element. Ultraviolet and violet excitation characteristics and uniform white light emission characteristics of the phosphor are distinguished from conventional phosphors, and may be variously applied to white light using nitride semiconductors. Since the phosphor is made of silicon oxide, it is chemically stable and has high reliability.

Description

Phosphor for white LED lamp.

The present invention provides a phosphor Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7) ), y, z, w]. Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z, w] Phosphor is blue, green, red It shows uniform light emission characteristics to the entire visible light region including, and has a wide range of absorption light from the near ultraviolet region to purple. Therefore, it is a phosphor that can be applied to a white lamp using various ultraviolet and violet light emitting diodes as excitation light.

A white lamp including a light emitting diode and a phosphor light conversion layer may be used as a back light of a color liquid crystal monitor. In addition, there is a characteristic of having a high efficiency and a long light emission life is considered to be able to replace the conventional lighting such as fluorescent lamps. The wider application area is abundantly applicable as display devices such as outdoor billboards, traffic signal indicators, and aviation and marine guidance.

Looking at the prior art in the field of the present invention as follows.

So far, examples of phosphors developed or in progress for white light emitting lamps using nitride semiconductors as excitation light of phosphors and emission characteristics of phosphors are as follows.

The phosphor YAG and the related series phosphors for commercially available white lamps currently do not emit blue light by themselves and have poor red light emission characteristics. In addition, since the excitation light has a narrow width of blue, it is difficult to develop a lamp having various colors with a white background. In addition, it is a big disadvantage that the change in the white light characteristics according to the wavelength change of the blue light is severe.

In the sulfide-based phosphor, which is under development, the elemental sulfur is easily replaced with oxygen when exposed to ultraviolet light, and is converted into an oxide structure. In this case, the brightness is remarkably lowered so that it can no longer be used, and thus the reliability of the light emitting device is not secured.

Ca ₈ Mg (SiO ₄ ) ₄ Cl ₂ : EU ²⁺ _y and Mn ²⁺ phosphors synthesized with Ca element and silicon oxide have also been studied in various ways. Phosphors with such a composition have strong monochromatic emission characteristics and react with other elements. Because it contains easy Ca element, it has shortcomings due to its weak thermal and chemical stability.

Most of the conventional phosphors exhibit strong luminescence properties only in a part of the visible light region, and thus are not suitable for white light emitting phosphors, and the excitation light often belongs to a short wavelength in the ultraviolet region. It is not suitable for the white light emitting lamp used.

The present invention relates to a phosphor capable of emitting white light by using ultraviolet and violet light emitting diodes as excitation light. The developed phosphor should have luminescent properties covering the entire visible light region and be a material that can be easily excited by ultraviolet and violet light. In addition, it must have high light conversion efficiency and should be applicable to high brightness device fabrication.

In addition, it must be composed of chemically stable elements in order to secure the reliability of the device and must be excellent in heat resistance generated from the operation of the device. In addition, it is necessary to be able to variously convert the light emission characteristics for a wide range of applications.

1 is represented by the general formula Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z, w] Schematic of the synthesis method of phosphors.

2 is a change in emission spectrum according to x value of Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y [(x = 0-7), y = 5 mol%] phosphor.

3 is a change in emission spectra of phosphors to which Mn ²⁺ _z is added to Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y phosphors. [(x = 0-7), y = 5 mol%, z = 5 mol%].

4 is a change in emission spectrum according to excitation light of Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z phosphors. [(x = 0-7), y = 5 mol%, z = 5 mol%].

5 is an excitation spectrum of Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z phosphors.

6 is white using Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z, w] phosphors Example of a light emitting diode lamp.

In order to achieve the above object, the phosphors developed in the present invention can be excited in various ultraviolet and violet wavelength ranges, show even luminescence properties in the entire visible light region, are manufactured using oxides, and are excellent in chemical stability and luminescent activators. By controlling the content of the material used as the (Activator) has the characteristic that the light conversion can be made in a variety of colors.

Referring to the manufacturing method of the phosphor developed for achieving the object of the invention as follows.

Phosphor substance Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z, w] SrCO ₃ , CaCO ₃ , MgO, SiO ₂ , and SrCl ₂ · 6H ₂ O as a substance were mixed well in the ratio of molar ratio 7-x: x: 1: 4: 1.5 (x = 0-7) Activator Eu ₂ O ₃ , MnO and Nm elements (Nm is an oxide consisting of at least one of Bi, Mn, Ce, Er, Pr, Cr, Sm, Dy, Eu) are suitable for the desired optical properties Add in molar ratio. Next, the mixed samples are finely ground to increase the reaction rate at the surface of the powder. When the mixed sample is put into an electric furnace and fired at 800 ° C to 1400 ° C while flowing a gas mixed with nitrogen and hydrogen, the reaction is completed. In order to remove excess SrCl ₂ , for example, the calcined sample is filtered through distilled water to precipitate only the synthesized phosphor, and excess SrCl ₂ is dissolved and removed to give Sr _8-x Ca having white luminescence properties. _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z, w] phosphors are prepared. 1 shows Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z, w] phosphors A schematic of the manufacturing method and process is shown.

Changes in the luminescence properties of the Eu ²⁺ luminescent activator according to the component ratio x of the host material Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ of the phosphor used in the present invention will be described in detail with reference to the accompanying drawings. [See FIG. 2]

Ca ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y The Ca element of the phosphor is partially or entirely replaced by Sr element, and is represented by the chemical formula of Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl 2: Eu ²⁺ _y When the phosphor is made, the blue light emission property becomes stronger as the amount of Sr replaced is increased, and when x = 4 or less when the content of Sr is higher than Ca, light emission properties corresponding to the entire visible light region start to appear. This change in luminescence properties is because the crystal field acting on Eu ²⁺ changes due to the increase in Sr. In the case of replacing Sr with Ca, the effect of reliability on the device is to replace the highly reactive Ca with Sr, which is less reactive with other elements, thereby increasing chemical stability and thereby improving the reliability of the device.

In the Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z, w] phosphors, Ca is converted into Ba. Substituents having a structure of Sr _8-x Ba _x Mg (SiO ₄ ) ₄ Cl 2: Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z, w] In case of development, the long life characteristics of Ba-based phosphors can be used. In this case too, the reliability of the device can be improved.

Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z, w according to each light-emitting activator Changes in the luminescence properties of the phosphors according to the respective activators Eu ²⁺ _y , Mn ²⁺ _z , and Nm ^{n +} _w may be described as follows.

In the case of Eu ²⁺ , the excitation and emission transitions are caused by 4f ⁶ 5d ¹ → 4f ⁷ , and are very sensitive and variously react to the crystal field of the surrounding crystal structure. Therefore, blue luminescence properties, which did not appear in Ca ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , are replaced by Sr, which is closer to Sr ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y phosphors. Therefore, the emission characteristics of blue gradually become stronger due to the change in crystal field on Eu ²⁺ .

In the case of Mn ²⁺ , the luminescence property can be confirmed from FIG. 3 that yellow light emission is enhanced when Mn ²⁺ is added to Sr ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y . This is because the light emission transition of Mn ²⁺ shows typical green and yellow light emission characteristics. In this case, it can be seen that the phenomenon of energy transfer from Eu ²⁺ to Mn ²⁺ occurs, whereby Eu 2+ emission is relatively decreased and Mn ²⁺ emission becomes stronger.

Finally, look at the case of Nm ^{n +,} Nm ^{n +} is to say the case of using at least one element of the elements of Bi, Mn, Ce, Er, Pr, Cr, Sm, Dy, Eu a n-valent light emitting activator (Activator) When added to Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , [(x = 0-7), y, z], various emission characteristics are exhibited. In the case of Eu ^3+, an element having a typical red light emission transition, unlike Eu ²⁺ , it is not affected by the surrounding crystal field. In the case of Pr ³⁺ , it is possible to obtain various luminescence when added to the crystals of Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ , (x = 0-7), which are highly influenced by the crystal field. I think. Sm ²⁺ , Mn ⁴⁺ , Cr ^{3+ are} also considered to be potent luminescent activators capable of enhancing the red luminescence properties of the phosphor.

By using the light emission characteristics of each of the above-described light-emitting activator can be made a phosphor having an even white light emission characteristics. As a first method, pure white light emission is obtained by adding Nm ^{n +} as a co-activator to the strong blue, yellow and weak red light emission characteristics of Sr ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z phosphors. Characteristics can be obtained. Alternatively, Sr ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y and Mn ²⁺ _z phosphors are mixed with Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Nm ^{n +} w phosphors in an appropriate ratio. In this case, it is possible to obtain white light emission characteristics which emit light in the entire visible light region. In addition, it is possible to manufacture a phosphor having a variety of colors on a white background, for this purpose, it is necessary to properly adjust the content of each light-emitting activator.

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Attached [FIG. 6] shows Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, according to the present invention. z, w] is a cross-sectional view showing an embodiment of a structure of a white light emitting lamp having a light conversion phosphor. (Nm ^{n +} uses at least one element of Bi, Mn, Ce, Er, Pr, Cr, Sm, Dy, Eu as an n-valent activator.)

As shown in FIG. 6, the present invention places the ultraviolet and infrared light emitting diodes at the bottom of the lamp, and mixes the phosphors with a resin that transmits the ultraviolet and violet light by 90% or more and applies the same to the top of the diode. In addition, an epoxy or resin that can reflect ultraviolet rays and violet light by 90% or more is manufactured in a convex form to protect the interior and to produce a lamp having directivity of white light. In addition to the use of resins and epoxies, the use of glass, which can act as a color barrier, can also be considered. In this case, a thin film of phosphor is applied on the glass that transmits more than 98% of the ultraviolet rays and purple, and then the glass which reflects more than 98% of the ultraviolet and purple light is covered therewith to block and reflect the emission of ultraviolet and purple light together with internal protection. Re-excitation of light maximizes luminous efficiency. In addition, the structure of the lamp in which the above two methods are properly mixed can be considered.

The present invention is not limited to the above-described embodiments and can be modified in various ways.

According to the present invention made as described above, Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z , w] When a material is used as a light conversion phosphor, a white lamp using ultraviolet and violet light emitting diodes as excitation light can be manufactured. The white lamp having such a structure has high lifespan and efficiency, which is highly reliable and can be applied to various display devices such as back-light of color liquid crystal display and next generation lighting.

Sr _8-x Ca _x Mg (SiO ₄ ) ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w [(x = 0-7), y, z, w] Adjusting the x, y, z, w values can adjust the color of the lamp, which may be the greatest advantage of the present invention in the field of next-generation lighting. (Nm ^{n +} uses at least one element of Bi, Mn, Ce, Er, Pr, Cr, Sm, Dy, Eu as an n-valent activator.)

Claims (9)

The composition of the phosphor is a general formula Sr _8-x Ca _x Mg (SiO ₄ ) _{4 in which} ultraviolet or violet light is used as an excitation light source and the excitation light source is irradiated to the photoconversion phosphor to emit light having a wide range of wavelengths. A light emitting device comprising a phosphor represented by Cl ₂ : Eu ²⁺ _y . 7 ≥ x ≥ 0, 0.8 ≥ y ≥ 0. The composition of the phosphor is a general formula Sr _8-x Ca _x Mg (SiO ₄ ) _{4 in which} ultraviolet or violet light is used as an excitation light source and the excitation light source is irradiated to the photoconversion phosphor to emit light having a wide range of wavelengths. A light emitting device comprising a phosphor represented by Cl ₂ : Mn ²⁺ _z . Provided that 7 ≥ x ≥ 0, 0.8 ≥ z ≥ 0. The composition of the phosphor is a general formula Sr _8-x Ca _x Mg (SiO ₄ ) _{4 in which} ultraviolet or violet light is used as an excitation light source and the excitation light source is irradiated to the photoconversion phosphor to emit light having a wide range of wavelengths. A light emitting device comprising a phosphor represented by Cl ₂ : Nm ^{n +} _w . However, 7 ≥ x ≥ 0, 4 ≥ n ≥ 0, 0.8 ≥ w ≥ 0, Nm is one or two or more selected from the elements of Bi, Mn, Ce, Er, Pr, Cr, Sm, Dy, Eu. The composition of the phosphor is a general formula Sr _8-x Ca _x Mg (SiO ₄ ) _{4 in which} ultraviolet or violet light is used as an excitation light source and the excitation light source is irradiated to the photoconversion phosphor to emit light having a wide range of wavelengths. A light emitting device comprising a phosphor represented by Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , or Nm ^{n +} _w . 7 ≥ x ≥ 0, 0.8 ≥ y ≥ 0, 0.8 ≥ z ≥ 0, 0.8 ≥ w ≥ 0, 4 ≥ n ≥ 1, Nm is Bi, Mn, Ce, Er, Pr, Cr, Sm, Dy, One or more selected from the elements of Eu. The composition of the phosphor is a general formula Sr _8-x Ba _x Mg (SiO ₄ ) _{4 in which} ultraviolet or violet light is used as an excitation light source and the excitation light source is irradiated to a photoconversion phosphor to emit light having a wide range of wavelengths. A light emitting device comprising a phosphor represented by Cl ₂ : Eu ²⁺ _y . 7 ≥ x ≥ 0, 0.8 ≥ y ≥ 0. The composition of the phosphor is a general formula Sr _8-x Ba _x Mg (SiO ₄ ) _{4 in which} ultraviolet or violet light is used as an excitation light source and the excitation light source is irradiated with a color conversion phosphor to emit light having a wide range of wavelengths. A light emitting device comprising a phosphor represented by Cl ₂ : Mn ²⁺ _z . Provided that 7 ≥ x ≥ 0, 0.8 ≥ z ≥ 0. The composition of the phosphor is a general formula Sr _8-x Ba _x Mg (SiO ₄ ) _{4 in which} ultraviolet or violet light is used as an excitation light source and the excitation light source is irradiated with a color conversion phosphor to emit light having a wide range of wavelengths. A light emitting device comprising a phosphor represented by Cl ₂ : Nm ^{n +} _w . However, 7 ≥ x ≥ 0, 4 ≥ n ≥ 0, 0.8 ≥ w ≥ 0, Nm is one or two or more selected from the elements of Bi, Mn, Ce, Er, Pr, Cr, Sm, Dy, Eu. The composition of the phosphor is a general formula Sr _8-x Ba _x Mg (SiO ₄ ) _{4 in which} ultraviolet or violet light is used as an excitation light source and the excitation light source is irradiated with a color conversion phosphor to emit light having a wide range of wavelengths. A light emitting device comprising a phosphor represented by Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , or Nm ^{n +} _w . 7 ≥ x ≥ 0, 0.8 ≥ y ≥ 0, 0.8 ≥ z ≥ 0, 0.8 ≥ w ≥ 0, 4 ≥ n ≥ 1, Nm is Bi, Mn, Ce, Er, Pr, Cr, Sm, Dy, One or more of the elements of Eu. The composition of the phosphor is a general formula Sr _8-x Ba _xv Ca _v Mg (SiO) in the structure of emitting ultraviolet light, violet and blue light as excitation light sources, and irradiating the excitation light source to the color conversion phosphor to emit light of a wide range of wavelengths. ₄ ) A light emitting device comprising a phosphor represented by ₄ Cl ₂ : Eu ²⁺ _y , Mn ²⁺ _z , Nm ^{n +} _w . 7≥x≥0, v = 8-x, 0.8≥y≥0, 0.8≥z≥0, 0.8≥w≥0, 4≥n≥1, Nm is Bi, Mn, Ce, Er, Pr, One or more selected from elements of Cr, Sm, Dy, and Eu.