JP2007314657A - Wavelength converting material using fluorescent substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wavelength-converting material that has high emission intensity, excellent weather resistance and high reliability. <P>SOLUTION: The wavelength-converting material comprises a nitride fluorescent substance absorbing near ultraviolet rays or blue color ray and emitting red light and represented by the formula: M<SB>w</SB>Al<SB>x</SB>Si<SB>y</SB>B<SB>z</SB>N<SB>((2/3)w+x(4/3)y+z)</SB>: Eu (M is at least one of Mg, Ca, Sr and Ba; 0.5≤w≤3, x=1, 0.5≤y≤3, 0≤z≤0.5), at least one kind of fluoresence body among the Ce-activated structure fluorescent substances represented by the formula: M'<SB>3</SB>(Al<SB>1-v</SB>Ga<SB>v</SB>)<SB>5</SB>O<SB>12</SB>(wherein M' is Lu, Y, Gd, and Tb, 0 ≤ v ≤ 0.8) and at least one of fluorescent substance among Ce activated garnet structure fluorescent substances is represented by general formula rR<SB>2</SB>O-sB<SB>2</SB>O<SB>3</SB>-tZnO<SB>2</SB>-uSiO<SB>2</SB>(wherein R is one of Li, Na, K, Rb, and Cs; 0.1≤r≤0.15, 0.4≤s≤0.6, 0.2≤t≤0.4, 0.05≤u≤0.2). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wavelength conversion material using a phosphor.

  A wavelength conversion material using a phosphor is prepared by mixing phosphor powder with a mold resin or the like made of an organic or inorganic binder resin that shields the light emitting surface of the light emitting element, and absorbing the light emitted from the light emitting element. The light is converted into the wavelength of. However, when the wavelength conversion material is composed of a phosphor layer containing an organic binder resin, the organic binder resin itself is deteriorated by light in a short wavelength region (ultraviolet region to blue region) with high output, coloring, etc. As a result, there is a problem that the light emission luminance is greatly reduced.

  In Patent Document 1, a mixture of phosphor powder, organic binder resin, and inorganic sintering aid is molded into a desired shape, and organic binder resin that causes deterioration of the phosphor layer is sintered and removed. It has been proposed to do.

  Patent Document 2 proposes an emission color conversion member in which an inorganic phosphor is dispersed in glass.

  However, there are cases where sufficient weather resistance and reliability cannot be obtained by the method of sintering and removing the organic binder resin. In addition, when sintering is performed at a high temperature, depending on the type of phosphor, the phosphor may be deteriorated or decomposed, resulting in a decrease in emission intensity.

Further, even when the phosphor has a softening point dispersed in the glass, the processing temperature becomes high, so that the phosphor is deteriorated or decomposed, and the emission intensity may be lowered.
JP 2004-161871 A JP 2003-258308 A

  An object of the present invention is to provide a wavelength conversion material having high emission intensity and excellent weather resistance and reliability.

Wavelength converting material of the present invention have the general formula _{M w Al x Si y B z} N ((2/3) w + x + (4/3) y + z): Eu ( wherein, M represents, Mg, Ca, Sr and Ba At least one selected, and w, x, y, and z satisfy 0.5 ≦ w ≦ 3, x = 1, 0.5 ≦ y ≦ 3, and 0 ≦ z ≦ 0.5. A nitride phosphor activated with europium (Eu) that absorbs near-ultraviolet or blue light and emits red light, and a general formula M ′ ₃ (Al _1-v Ga _v ) ₅ O ₁₂ : Ce ( In the formula, M is at least one selected from Lu, Y, Gd, and Tb, and v is 0 ≦ v ≦ 0.8, and is activated by cerium (Ce). at least one phosphor of garnet structure phosphors formula _{rR 2 O-sB 2 O 3} -tZnO-uSiO ₂ (wherein R is at least one selected from Li, Na, K, Rb, and Cs, r, s, t, and u represent a molar ratio, and 0.1 ≦ r ≦ 0.15) 0.4 ≦ s ≦ 0.6, 0.2 ≦ t ≦ 0.4, and 0.05 ≦ u ≦ 0.2.).

  The nitride phosphor and the garnet structure phosphor respectively represented by the above general formulas are generally phosphors having low heat resistance, and are easily deteriorated or decomposed when heated to a high temperature. For this reason, when producing a wavelength conversion material in which a phosphor is dispersed in glass using a conventional glass material, the processing temperature increases, the phosphor deteriorates or decomposes, and the emission intensity of the wavelength conversion material decreases. There was a problem.

  Further, many glass materials having a low softening point are generally difficult to become transparent, and simply having a low softening point is not suitable as a material for dispersing the phosphor. There is also a problem that a specific component contained in the glass material reacts with the phosphor to deteriorate the phosphor.

In the present invention, the general formula rR ₂ O—sB ₂ O ₃ —tZnO—uSiO ₂ (wherein R is at least one selected from Li, Na, K, Rb, and Cs, and r, s, t and u represent molar ratios, and 0.1 ≦ r ≦ 0.15, 0.4 ≦ s ≦ 0.6, 0.2 ≦ t ≦ 0.4, 0.05 ≦ u ≦ 0.2. By using the glass material represented by the following formula as a dispersion medium, it is possible to obtain a wavelength conversion material having high emission intensity and excellent weather resistance and reliability even when the phosphor is used.

In the glass material, R ₂ O is an alkali metal oxide, and R contains at least one selected from Li, Na, K, Rb, and Cs. R ₂ O is a component that lowers the softening point of the glass. If the value of r, which is the molar ratio of R ₂ O, is greater than 0.15, the moisture resistance tends to be reduced. On the other hand, if the value of r is smaller than 0.1, the softening point of the glass tends to be high, and the phosphor tends to deteriorate.

B ₂ O ₃ is a component that forms a glass network, and vitrifies stably when the value of s, which is the molar ratio thereof, is in the range of 0.4 to 0.6. In addition, when the value of s is out of this range, the glass tends to be crystallized easily, the transmittance is lowered, the luminance is lowered, and the light emission intensity is easily lowered.

  ZnO is a component that forms a network of glass, and vitrifies stably when the value of t, which is the molar ratio thereof, is in the range of 0.2 to 0.4. When the value of t is out of this range, the glass tends to be crystallized easily, the transmittance is lowered, the luminance is lowered, and the light emission intensity is easily lowered.

SiO ₂ is a component that enhances moisture resistance. If the value of u, which is the molar ratio of SiO ₂ , is greater than 0.2, the softening point of the glass tends to be high, and the phosphor tends to deteriorate. On the other hand, when the value of u is smaller than 0.05, it is difficult to obtain the effect of improving moisture resistance.

  The softening point of the glass material of the present invention is preferably 600 ° C. or less, and more preferably in the range of 500 to 560 ° C. When the softening point of the glass material is increased, the phosphor tends to be easily degraded or decomposed. Further, when the softening point of the glass material is lowered, the glass material and the phosphor material tend to react easily. By making the softening point of the glass material in such a range, a wavelength conversion material in which the phosphor is dispersed in the glass material is produced without causing a reaction between the glass and the phosphor, or deterioration or decomposition of the phosphor. Can do.

  The nitride phosphor used as the phosphor is a phosphor that absorbs near ultraviolet light or blue light and emits red light. Near ultraviolet or blue light is generally light having a wavelength in the range of 360 nm to 480 nm. Red light is generally light having a wavelength in the range of 600 nm to 700 nm.

Nitride phosphor used in the present invention have the general formula _{M w Al x Si y B z} N ((2/3) w + x + (4/3) y + z): Eu ( wherein, M is Mg, Ca, Sr and (At least one selected from Ba, and w, x, y, and z satisfy 0.5 ≦ w ≦ 3, x = 1, 0.5 ≦ y ≦ 3, and 0 ≦ z ≦ 0.5.) It is represented by By setting w, x, y, and z within the above range, a phosphor with high emission luminance can be obtained.

The garnet structure phosphor used in the present invention has a general formula M ′ ₃ (Al _1-v Ga _v ) ₅ O ₁₂ : Ce (where M ′ is at least one selected from Lu, Y, Gd, and Tb). And v satisfies 0 ≦ v ≦ 0.8. By setting t within the above range, a phosphor with high emission luminance can be obtained. The garnet structure phosphor in the present invention can absorb near ultraviolet light or blue light and emit yellow to green light. Therefore, by using the nitride phosphor and the garnet structure phosphor in combination, a wavelength conversion material that emits white light can be obtained.

  The content of the phosphor in the wavelength conversion material of the present invention is appropriately selected depending on the type of the phosphor and is not particularly limited, but is generally preferably in the range of 1.0 to 25% by weight, More preferably, it is in the range of 8 to 15% by weight. If the phosphor content is too large, bubbles will tend to remain in the sintered body when the phosphor and glass material are mixed and sintered. As a result, the transmittance decreases. As a result, the luminance decreases and the emission intensity tends to decrease. Moreover, when there is too little content of a fluorescent substance, the ratio of excitation light will increase too much and it exists in the tendency for chromaticity to shift | deviate.

  The wavelength conversion material of the present invention can be produced by mixing a phosphor and a glass material and sintering the mixed powder at a temperature equal to or higher than the softening point of the glass material. If necessary, a resin binder can be added and pressure-molded to prepare a preform having a predetermined shape, which is then fired to prepare a wavelength conversion material having a predetermined shape.

  According to the present invention, a wavelength conversion material having high emission intensity and excellent weather resistance and reliability can be obtained.

  Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited to the following examples.

Example 1
A wavelength conversion material was produced using the phosphor and glass material (softening point 520 ° C.) shown in Table 1. Specifically, the phosphor and glass material shown in Table 1 were sufficiently mixed by a dry method using a mixer, and this raw material was packed in a crucible and heated and fired at 520 ° C. for 20 minutes in an air atmosphere. Thereby, a desired wavelength conversion material was obtained.

(Example 2)
A wavelength conversion material was produced using the phosphor and glass material (softening point 520 ° C.) shown in Table 1. Specifically, the phosphor and glass material shown in Table 1 were sufficiently mixed by a dry method using a mixer, and this raw material was packed in a crucible and heated and fired at 530 ° C. for 20 minutes in an air atmosphere. Thereby, a desired wavelength conversion material was obtained.

(Example 3)
A wavelength conversion material was prepared using the phosphor and glass material (softening point 540 ° C.) shown in Table 1. Specifically, the phosphor and glass material shown in Table 1 were sufficiently mixed by a dry method using a mixer, and this raw material was packed in a crucible and heated at 540 ° C. for 20 minutes in an air atmosphere and fired. Thereby, a desired wavelength conversion material was obtained.

Example 4
A wavelength conversion material was prepared using the phosphor and glass material (softening point 550 ° C.) shown in Table 1. Specifically, the phosphor and glass material shown in Table 1 were sufficiently mixed by a dry method using a mixer, and this raw material was packed in a crucible and heated at 540 ° C. for 20 minutes in an air atmosphere and fired. Thereby, a desired wavelength conversion material was obtained.

(Comparative Example 1)
A wavelength conversion material was prepared using the phosphor and glass material (softening point 820 ° C.) shown in Table 1. Specifically, the phosphor and glass material shown in Table 1 were sufficiently mixed by a dry method using a mixer, and this raw material was packed in a crucible and heated and baked at 800 ° C. for 20 minutes in an air atmosphere. Thereby, a desired wavelength conversion material was obtained.

[Evaluation of luminescent color]
The wavelength conversion materials prepared in Examples 1 to 4 and Comparative Example 1 were irradiated with excitation light of 460 nm, and the emission color emitted from the wavelength conversion material was measured using a chromaticity meter. The color of the emission color and the CIE coordinates (x, y) are as follows.
Example 1: White: x / y = 0.343 / 0.345
Example 2: White: x / y = 0.402 / 0.389
Example 3: Red: x / y = 0.655 / 0.337
Example 4: Yellowish green: x / y = 0.335 / 0.589
Comparative Example 1: little luminescence was obtained

[Evaluation of luminous intensity]
The wavelength conversion materials of Examples 1 to 4 were irradiated with excitation light of 460 nm, and the emission luminance of the emitted light was measured. The light emission luminance is a relative value when the resin-sealed YAG phosphor is 100%.
Example 1: 95.5%
Example 2: 90.4%
Example 3: 20.3%
Example 4: 112.3%

[Reliability evaluation]
Reliability was evaluated using the wavelength conversion material produced in Example 1. As Comparative Example 2, a wavelength conversion material in which a phosphor was dispersed in a resin using an equal amount of resin instead of the glass material in Example 1, was evaluated for reliability. The power of the irradiation light was changed, and the luminous flux of light emitted from the wavelength conversion material at that time was measured and evaluated.

  FIG. 2 is a schematic view showing a light emitting device used for reliability evaluation. A light emitting element 11 made of a laser diode (LD) is provided in the light source 10, and the light 1 emitted from the light emitting element 11 passes through the lens 13 and is emitted from the emitting unit 12. One end of an optical fiber 20 is connected to the emitting section 12, and a wavelength conversion material 30 is attached to the output section 21 that is the other end of the optical fiber 20. The light emitting element 11 is a GaN-based semiconductor element and emits light in the vicinity of 405 nm. The wavelength of the light is converted in the wavelength conversion material 30, and the white light 2 is irradiated from the wavelength conversion material 30.

  FIG. 1 shows the evaluation results of evaluating the reliability as described above. The temperature (retention temperature: Ta) at the time of evaluating reliability was changed to 25 ° C., 60 ° C., and 100 ° C., respectively, and the evaluation was performed under each condition. In FIG. 1, the horizontal axis indicates the light output from the laser diode (LD), and the vertical axis indicates the luminous flux of the light emitted from the wavelength conversion material. This means that the reliability is low when the luminous flux is reduced when high output energy is irradiated.

  As shown in FIG. 1, in Example 1 using the glass material of the present invention, the luminous flux does not decrease even when high output energy is irradiated. On the other hand, in the wavelength conversion material of Comparative Example 2 using a resin, when high-power energy is irradiated, the luminous flux is lowered.

  As described above, by using the wavelength conversion material of the example, a wavelength conversion material having high emission luminance and excellent reliability can be obtained.

The figure which shows the relationship between the output from a light emitting element, and the light beam from a wavelength conversion material. The schematic diagram which shows the light-emitting device used for evaluation of reliability.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light 2 ... Light emission from wavelength conversion material 10 ... Light source 11 ... Light emitting element 12 ... Output part 13 ... Lens 20 ... Optical fiber 21 ... Output part 30 ... Wavelength conversion material

Claims (1)

Formula _{M w Al x Si y B z} N ((2/3) w + x + (4/3) y + z): Eu ( wherein, M is at least one selected from Mg, Ca, Sr and Ba, w , X, y, and z satisfy 0.5 ≦ w ≦ 3, x = 1, 0.5 ≦ y ≦ 3, and 0 ≦ z ≦ 0.5). A nitride phosphor activated with europium (Eu) that absorbs and emits red light, and a general formula M ′ ₃ (Al _1-v Ga _v ) ₅ O ₁₂ : Ce (where M ′ is Lu , Y, Gd, and Tb, and v is 0 ≦ v ≦ 0.8.) Of the garnet structure phosphor activated by cerium (Ce) At least one phosphor,
Formula _rR in _{2 O-sB 2 O 3 -tZnO} -uSiO 2 ( wherein, R, Li, at least one selected Na, K, Rb, and from Cs, r, s, t, and u The molar ratio is 0.1 ≦ r ≦ 0.15, 0.4 ≦ s ≦ 0.6, 0.2 ≦ t ≦ 0.4, and 0.05 ≦ u ≦ 0.2. A wavelength conversion material characterized by being contained in a glass material.

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