TW201542766A - Wavelength conversion member and light emitting device using same - Google Patents

Abstract

Provided are: a wavelength conversion member which is not susceptible to decrease of the luminous intensity over time in cases where the wavelength conversion member is irradiated with light from an LED or LD; and a light emitting device which uses this wavelength conversion member. A wavelength conversion member which is obtained by dispersing an inorganic phosphor in a glass matrix, and which is characterized in that: the glass matrix contains, in mol%, 40-60% of SiO2, 0.1-35% of B2O3, 0.1-10% of Al2O3, 0-10% of Li2O, 0-10% of Na2O, 0-10% of K2O, 0.1-10% of (Li2O + Na2O + K2O), 0-35% of MgO, 0-35% of CaO, 0-35% of SrO, 0-35% of BaO, 0.1-35% of (MgO + CaO + SrO + BaO) and 0-15% of ZnO; and the inorganic phosphor is composed of at least one phosphor selected from among oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, oxychloride phosphors, halide phosphors, aluminate phosphors and halophosphate chloride phosphors.

Description

Wavelength conversion member and light-emitting device using the same

The present invention relates to a wavelength conversion member for converting a wavelength of light emitted from a light-emitting element such as a light emitting diode (LED) or a laser diode (LD: Laser Diode) to another wavelength.

In recent years, as a next-generation light source that replaces a fluorescent lamp or an incandescent lamp, attention has been paid to the use of a light source using LEDs or LDs from the viewpoint of low power consumption, small size and light weight, and easy adjustment of the amount of light. As an example of such a next-generation light source, for example, Patent Document 1 discloses a light source in which a wavelength conversion member that absorbs and converts a part of light from an LED into yellow light is disposed on an LED that emits blue light. The light source emits white light which is a combined light of blue light emitted from the LED and yellow light emitted from the wavelength converting member.

As the wavelength converting member, those used in the case where an inorganic phosphor is dispersed in a resin matrix have been used. However, when the wavelength conversion member is used, there is a problem that the resin is deteriorated due to light from the LED, and the luminance of the light source is liable to become low. In particular, there is a problem that the resin matrix is deteriorated due to heat generated by the LED or short-wavelength (blue-ultraviolet) light of high energy, causing discoloration or deformation.

Therefore, a wavelength conversion member including a completely inorganic solid in which an inorganic phosphor is dispersed and fixed in a glass matrix in place of a resin has been proposed (for example, refer to Patent Documents 2 and 3). This wavelength conversion member is characterized in that the glass to be a base material is less likely to be deteriorated by heat of the TED wafer or irradiation light, and it is less likely to cause discoloration or deformation.

However, the wavelength conversion members described in Patent Documents 2 and 3 have baking at the time of manufacture. The problem of deterioration of the inorganic phosphor is caused by burning, and the brightness is easily deteriorated. In particular, in general lighting, special lighting, and the like, since high color rendering properties are required, it is necessary to use an inorganic phosphor having a relatively low heat resistance such as red or green, and the deterioration of the inorganic phosphor becomes remarkable. tendency. Therefore, the wavelength conversion member which reduces the softening point of the glass powder by containing an alkali metal oxide in the glass composition is proposed (for example, refer patent document 4). Since the wavelength conversion member can be produced by firing at a relatively low temperature, deterioration of the inorganic phosphor at the time of baking can be suppressed.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2000-208815

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2003-258308

[Patent Document 3] Japanese Patent No. 4895541

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2007-302858

The wavelength conversion member described in Patent Document 4 has a problem that the luminous intensity tends to decrease over time. As the output of light sources such as LEDs or LDs has further increased in recent years, the decrease in luminous intensity over time has become more pronounced.

Accordingly, an object of the present invention is to provide a wavelength conversion member having a small decrease in luminous intensity over time when an LED or an LD is irradiated, and a light-emitting device using the same.

The wavelength conversion member of the present invention is characterized in that it is obtained by dispersing an inorganic phosphor in a glass matrix, and the glass substrate contains SiO ₂ 40 to 60%, B ₂ O ₃ 0.1 to 35%, and Al in terms of mol%. ₂ O ₃ 0.1~10%, Li ₂ O 0~10%, Na ₂ O 0~10%, K ₂ O 0~10%, Li ₂ O+Na ₂ O+K ₂ O 0.1~10%, MgO 0 ~45%, CaO 0~45%, SrO 0~45%, BaO 0~45%, MgO+CaO+SrO+BaO 0.1~45%, and ZnO 0~15%, and the inorganic fluorescent system is selected from oxides Phosphor, nitride phosphor, oxynitride phosphor, chloride phosphor, oxychloride phosphor, halide phosphor, aluminate phosphor, and halophosphate phosphor At least one of the group consisting of.

The inventors have found that the decrease in the luminous intensity of the wavelength converting member over time is particularly affected by the alkali metal component or the SiO ₂ component contained in the glass composition. It is speculated that the mechanism is as follows.

When the excitation light is irradiated to the glass substrate containing the alkali metal element in the composition, the electrons present in the outermost shell of the oxygen ions in the glass matrix are excited by the energy of the excitation light to be detached from the oxygen ions. A part of it combines with the alkali ions in the glass matrix to form a color center (here, alkali ions escape to form vacancies). On the other hand, the holes generated by the escape of electrons move in the glass matrix, and a part of the holes are trapped to the vacancies formed after the escape of the alkali ions to form a color center. It is considered that the coloring centers formed in the glass matrix become absorption sources of excitation light or fluorescence, and the light-emitting intensity of the wavelength conversion member is lowered. Further, there is a tendency that electrons, holes, and alkali ions in the glass matrix become active due to heat generated by the inorganic phosphor (heat generated by wavelength conversion loss). Thereby, the formation of the coloring center is accelerated, and the luminous intensity is easily lowered. Therefore, in the present invention, by containing an alkali metal element as an essential component and limiting the content thereof to less as described above, the increase in the softening point is suppressed, and the generation of the coloring center is suppressed.

Further, in the case where the SiO ₂ content is large in the composition, the ratio of Si-O-Si bonds as a network forming agent in the glass matrix increases, and the glass matrix structure is stabilized. Therefore, the non-bridged oxygen formed by the cleavage of the bond between Si and O in the Si-O-Si bond is stably maintained, and the non-bridged oxygen becomes a coloring center, which causes a decrease in luminescence intensity. On the other hand, when the content of SiO _{2 is} small in the composition, the content of other components is relatively increased, and the bond other than the Si—O—Si bond is increased (for example, Ba or Na is entered between Si and O, etc.). Element), so the stability of the glass matrix structure is reduced. In the case where non-bridged oxygen is formed in this state, since the stability of the bonding state around the Si element is lowered, it is not easy to stably maintain the non-bridged oxygen. As a result, the formation of the coloring center is suppressed.

Further, the glass substrate of the wavelength converting member of the present invention contains an alkaline earth oxide (including MgO) as an essential component. Alkaline earth oxides can hinder the movement of alkali metal ions or other ions in the glass matrix. As a result, it is difficult to form a coloring center, and it is possible to suppress a decrease in the luminous intensity over time.

In the wavelength conversion member of the present invention, it is preferred that the glass substrate contains 0.1% or more of Li ₂ O, Na ₂ O, and K ₂ O, respectively.

In the wavelength converting member of the present invention, it is preferred that the glass substrate has a softening point of 400 to 800 °C.

The wavelength converting member of the present invention preferably contains 0.01 to 30% by mass of an inorganic phosphor.

The wavelength converting member of the present invention preferably contains a powder sintered body.

A light-emitting device according to the present invention is characterized in that it includes the wavelength conversion member and a light source that emits excitation light to the wavelength conversion member.

According to the present invention, it is possible to provide a wavelength conversion member having a small decrease in luminous intensity over time when irradiating light of an LED or an LD, and a light-emitting device using the same.

1‧‧‧Lighting device

2‧‧‧wavelength conversion component

3‧‧‧Light source

L1‧‧‧Excited light

L2‧‧‧Fluorescent

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic side view of a light-emitting device according to an embodiment of the present invention.

The wavelength conversion member of the present invention is obtained by dispersing an inorganic phosphor in a glass matrix. The glass matrix contains 40 to 60% of SiO ₂ , 0.1 to 35% of B ₂ O ₃ , 0.1 to 10% of Al ₂ O _{3 ,} 0.1 to 10% of Li ₂ O, 0 to 10% of Na ₂ O, and K in terms of mole %. ₂ O 0~10%, Li ₂ O+Na ₂ O+K ₂ O 0.1~10%, MgO 0~45%, CaO 0~45%, SrO 0~45%, BaO 0~45%, MgO+CaO +SrO+BaO 0.1~45%, and ZnO 0~15%. The reason why the glass composition range is thus limited will be described below.

SiO ₂ forms a component of the glass network. The content of SiO ₂ is 40 to 60%, preferably 45 to 55%. When the content of SiO ₂ is too small, there is a tendency that weather resistance or mechanical strength is lowered. On the other hand, when the content of SiO ₂ is too large, the luminescence intensity tends to decrease with time. Further, when the wavelength conversion member is manufactured, the sintering temperature becomes high, and the inorganic phosphor is easily deteriorated.

B ₂ O ₃ is a component which lowers the melting temperature and remarkably improves the meltability. The content of B ₂ O ₃ is from 0.1 to 35%, preferably from 1 to 30%. If the content of B ₂ O ₃ is too small, the above effects are not easily obtained. Further, when the wavelength conversion member is manufactured, the sintering temperature becomes high, and the inorganic phosphor is easily deteriorated. On the other hand, when the content of B ₂ O ₃ is too large, the luminous intensity tends to decrease with time. Moreover, weather resistance is liable to lower.

Further, the ratio of SiO ₂ to B ₂ O ₃ of SiO ₂ /B ₂ O ₃ (mole ratio) is preferably 1 to 7, 1 to 6.5, 1.1 to 6, 1.15 to 5, 1.2 to 4, and 1.5. ~3.5, especially good is 1.7~2.5. When the value of SiO ₂ /B ₂ O ₃ is too large, the ratio of SiO ₂ becomes large, and it is easy to form a coloring center due to the detachment of the O element, and the luminous intensity tends to decrease with time. On the other hand, when the value of SiO ₂ /B ₂ O ₃ is too small, the ratio of B ₂ O ₃ becomes large, and weather resistance is liable to lower.

Al ₂ O ₃ is a component that improves weather resistance or mechanical strength. The content of Al ₂ O ₃ is 0.1 to 10%, preferably 2 to 8%. If the content of Al ₂ O ₃ is too small, the above effects are not easily obtained. On the other hand, when the content of Al ₂ O ₃ is too large, the meltability tends to decrease.

Further, in order to achieve high weather resistance, the content of SiO ₂ + B ₂ O ₃ + Al ₂ O ₃ is preferably 55% or more, more preferably 60% or more, and further preferably set to 65% or more, and particularly preferably 67% or more, and most preferably 70% or more. The upper limit of the content of SiO ₂ + B ₂ O ₃ + Al ₂ O ₃ is not particularly limited, and if it is too large, the meltability is liable to lower. Therefore, it is preferably 85% or less, more preferably 84% or less. It is preferably set to 83% or less.

Li ₂ O, Na ₂ O, and K ₂ O are components which lower the melting temperature and improve the meltability and lower the softening point. The content of the components is 0 to 10%, preferably 0 to 5%, more preferably 0.1 to 2%. If the content of these components is too large, the weather resistance tends to decrease.

Further, the content of Li ₂ O+Na ₂ O+K ₂ O is 0.1 to 10%, preferably 1 to 7%, more preferably 2 to 5%. If the content of Li ₂ O+Na ₂ O+K ₂ O is too small, the softening point is not easily lowered. On the other hand, when the content of Li ₂ O+Na ₂ O+K ₂ O is too large, the weather resistance is liable to lower, and the light emission intensity is likely to decrease with time due to light irradiation of LED or LD. Li ₂ O, Na ₂ O, and K ₂ O are preferably used in combination of two or more kinds, particularly three types. Specifically, it is preferable to contain 0.1% or more of Li ₂ O, Na ₂ O, and K ₂ O, respectively. If so, the softening point can be efficiently reduced by mixing the alkali effect. Moreover, when the content of each basic oxide is made equal, the mixed alkali effect is easily obtained.

In order to achieve high weather resistance, it is preferred to appropriately adjust the total amount of SiO ₂ , B ₂ O ₃ and Al ₂ O _{3 which are} components which contribute to improvement of weather resistance, and the alkali metal oxide which is a cause of deterioration in weather resistance. The ratio of the content of (Li ₂ O, Na ₂ O and K ₂ O). Specifically, (Li ₂ O+Na ₂ O+K ₂ O)/(SiO ₂ +B ₂ O ₃ +Al ₂ O ₃ ) (mole ratio) is preferably 0.2 or less, more preferably 0.18 or less, and further It is preferably 0.15 or less.

MgO, CaO, SrO, and BaO are components which lower the melting temperature and improve the meltability and lower the softening point. Further, since the movement of ions which cause the formation of the coloring center due to the irradiation of the light of the LED or the LD is inhibited, the effect of suppressing the decrease in the luminous intensity over time is also obtained. The content of the components is 0 to 45%, preferably 10 to 45%, and particularly preferably 15 to 35%. If the content of these components is too large, the weather resistance tends to decrease. Further, the hindrance of BaO having a large mass number is a large effect of the movement of ions which is a cause of forming a coloring center, and the temporal decrease of the luminous intensity can be effectively suppressed.

Further, the content of MgO+CaO+SrO+BaO is 0.1 to 45%, preferably 0.1 to 40%, more preferably 0.1 to 35%, further preferably 1 to 30%, and particularly preferably 5 to 25%. . When the content of MgO+CaO+SrO+BaO is too small, the softening point is not easily lowered, and the effect of suppressing the decrease in luminous intensity over time is not easily obtained. On the other hand, when the content of MgO+CaO+SrO+BaO is too large, the weather resistance is liable to lower.

ZnO is a component which lowers the melting temperature and improves the meltability. The content of ZnO is 0~ 15%, preferably 0 to 12%, more preferably 0 to 10%, and still more preferably 1 to 7%. When the content of ZnO is too large, the weather resistance tends to decrease.

Further, in addition to the above components, various components may be contained within the range which does not impair the effects of the present invention. For example, P ₂ O ₅ , La ₂ O ₃ , Ta ₂ O ₅ , TeO ₂ , TiO may be contained in a range of 15% or less, further 10% or less, particularly 5% or less, and 30% or less in total. ₂ , Nb ₂ O ₅ , Gd ₂ O ₃ , Y ₂ O ₃ , CeO ₂ , Sb ₂ O ₃ , SnO ₂ , Bi ₂ O ₃ and ZrO _{2 ,} and the like. Also, it may contain F. Since F has an effect of lowering the softening point, it is possible to suppress the decrease in the luminous intensity over time while maintaining the softening point by containing the alkali metal component which is one of the causes of forming the coloring center. The content of F is preferably 0 to 20%, 0 to 10%, and particularly preferably 0.1 to 5% in terms of anion %.

The softening point of the glass substrate is preferably from 400 to 800 ° C, more preferably from 450 to 750 ° C, and still more preferably from 500 to 700 ° C. If the softening point is too low, mechanical strength and weather resistance are liable to lower. On the other hand, if the softening point is too high, the inorganic phosphor is likely to be deteriorated by baking at the time of production.

Furthermore, in most cases, the refractive index of the inorganic phosphor is higher than that of the glass. In the wavelength conversion member, when the refractive index difference between the inorganic phosphor and the glass substrate is large, the excitation light is easily scattered at the interface between the inorganic phosphor and the glass substrate. As a result, the irradiation efficiency of the excitation light to the inorganic phosphor becomes high, and the luminous efficiency is easily improved. However, if the difference in refractive index between the inorganic phosphor and the glass substrate is too large, excessive scattering of the excitation light tends to cause scattering loss, and the luminous efficiency tends to decrease. In view of the above, the difference in refractive index between the inorganic phosphor and the glass substrate is preferably about 0.001 to 0.5. Further, the refractive index (nd) of the glass substrate is preferably from 1.45 to 1.8, more preferably from 1.47 to 1.75, still more preferably from 1.48 to 1.6.

The inorganic fluorescent system in the present invention is selected from the group consisting of oxide phosphors (including garnet phosphors such as YAG (Yttrium Aluminum Garnet) phosphors), nitride phosphors, and oxynitride. At least one of a group consisting of a substance phosphor, a chloride phosphor, an oxychloride phosphor, a halide phosphor, an aluminate phosphor, and a halophosphate phosphor. Among these inorganic phosphors, the oxide phosphor, the nitride phosphor, and the oxynitride phosphor have high heat resistance and are relatively less likely to be deteriorated during firing, which is preferable. Further, the nitride phosphor and the oxynitride phosphor have the characteristics of converting the near-ultraviolet-blue excitation light into a wide wavelength region of green to red, and the luminescence intensity is relatively high. Therefore, the nitride phosphor and the oxynitride phosphor are particularly effective as an inorganic phosphor for a wavelength conversion member for a white LED element. In order to suppress heat conduction from the inorganic phosphor to the glass substrate, a coated inorganic phosphor may be used. Thereby, activation of movement of electrons, holes, and alkali ions in the glass matrix can be suppressed, and as a result, formation of a coloring center can be suppressed. The coating material is preferably an oxide. In addition, as the phosphor other than the above, a sulfide phosphor is exemplified, but the sulfide phosphor is not deteriorated in the present invention because it deteriorates over time or reacts with the glass substrate to easily reduce the light-emitting intensity.

Examples of the inorganic phosphor include an excitation band at a wavelength of 300 to 500 nm and an emission peak at a wavelength of 380 to 780 nm, and particularly blue (wavelength: 440 to 480 nm), green (wavelength: 500 to 540 nm), and yellow. (wavelength 540~595nm), red (wavelength 600~700nm) light.

An inorganic phosphor that emits blue light when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm, (Sr, Ba) MgAl ₁₀ O ₁₇ : Eu ²⁺ , (Sr, Ba) ₃ MgSi ₂ O ₈ : Eu ²⁺ and the like.

The inorganic phosphor that emits green fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm includes SrAl ₂ O ₄ :Eu ²⁺ , SrBaSiO ₄ :Eu ²⁺ , and Y ₃ (Al, Gd) ₅ O ₁₂ :Ce ³⁺ , SrSiON:Eu ²⁺ , BaMgAl ₁₀ O ₁₇ :Eu ²⁺ ,Mn ²⁺ , Ba ₂ MgSi ₂ O ₇ :Eu ²⁺ , Ba ₂ SiO ₄ :Eu ²⁺ ,Ba ₂ Li ₂ Si ₂ O ₇ :Eu ²⁺ , BaAl ₂ O ₄ :Eu ^{2+ ,} and the like.

Examples of the inorganic phosphor that emits green fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm include SrAl ₂ O ₄ :Eu ²⁺ , SrBaSiO ₄ :Eu ²⁺ , and Y ₃ (Al,Gd). ₅ O ₁₂ :Ce ³⁺ , SrSiON:Eu ²⁺ , β-SiAlON:Eu ^{2+ ,} and the like.

The inorganic phosphor which emits yellow fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm is exemplified by La ₃ Si ₆ N ₁₁ :Ce ³⁺ or the like.

The inorganic phosphor which emits yellow fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm is exemplified by Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ³⁺ , Sr ₂ SiO ₄ : Eu ^{2+ .} .

The inorganic phosphor which emits red fluorescent light when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm can be exemplified by MgSr ₃ Si ₂ O ₈ :Eu ²⁺ , Mn ²⁺ , Ca ₂ MgSi ₂ O _{7 .} :Eu ²⁺ , Mn ^2+, etc.

Examples of the inorganic phosphor that emits red fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm include CaAlSiN ₃ :Eu ²⁺ , CaSiN ₃ :Eu ²⁺ , and (Ca,Sr) ₂ Si ₅ N. ₈ : Eu ²⁺ , α-SiAlON: Eu ^2+, and the like.

Further, a plurality of kinds of inorganic phosphors may be mixed and used in combination with the wavelength region of the excitation light or the light emission. For example, when the excitation light is irradiated in the ultraviolet region to obtain white light, the inorganic phosphor emitting blue, green, yellow, or red fluorescent light may be used by mixing.

The luminous efficiency (lm/W) of the wavelength conversion member varies depending on the type or content of the inorganic phosphor, the thickness of the wavelength conversion member, and the like. The content of the inorganic phosphor and the thickness of the wavelength converting member may be appropriately adjusted so that the luminous efficiency is optimal. When the content of the inorganic phosphor is too large, there is a problem that it is difficult to sinter or the porosity is increased, and the excitation light is efficiently irradiated to the inorganic phosphor or the mechanical strength of the wavelength conversion member is lowered. On the other hand, if the content of the inorganic phosphor is too small, it is difficult to obtain a desired luminescent intensity. In this regard, the content of the inorganic phosphor in the wavelength converting member of the present invention is preferably from 0.01 to 30% by mass, more preferably from 0.05 to 25% by mass, still more preferably from 0.08 to 20% by mass.

Further, the wavelength conversion member which aims to reflect the fluorescent light generated in the wavelength conversion member to the excitation light incident side and mainly extract only the fluorescence to the outside may be out of the above range, and the emission intensity may be maximized. Increase the content of inorganic phosphors (for example It is 30 to 80% by mass, and further 40 to 75% by mass).

In addition to the inorganic phosphor, the wavelength conversion member of the present invention may contain a light-diffusing material such as alumina, ceria or magnesia in an amount of 30% by mass or less based on the total amount.

The wavelength converting member of the present invention preferably contains a powder sintered body. Specifically, it is preferably a sintered body containing a mixed powder of a glass powder and an inorganic phosphor powder. In this case, the wavelength conversion member in which the inorganic phosphor is uniformly dispersed in the glass substrate can be easily produced.

The maximum particle diameter D _{max of the} glass powder is preferably 200 μm or less, more preferably 150 μm or less, still more preferably 105 μm or less. The average particle diameter D _{50 of the} glass powder is preferably 0.1 μm or more, more preferably 1 μm or more, still more preferably 2 μm or more. When the maximum particle diameter D _{max of} the glass powder is too large, the excitation light is less likely to be scattered in the obtained wavelength conversion member, and the luminous efficiency is liable to lower. Further, when the average particle diameter D _{50 of} the glass powder is too small, the excitation light is excessively scattered in the obtained wavelength conversion member, and the luminous efficiency is liable to lower.

Further, in the present invention, the maximum particle diameter D _max and the average particle diameter D ₅₀ refer to values measured by a laser diffraction method.

The calcination temperature of the mixed powder containing the glass powder and the inorganic phosphor is preferably within ±150 ° C of the softening point of the glass powder, more preferably within ±100 ° C of the softening point of the glass powder. If the baking temperature is too low, the glass powder does not flow, and a dense sintered body is not easily obtained. On the other hand, when the baking temperature is too high, the inorganic phosphor component is eluted into the glass to lower the luminescence intensity, or the inorganic phosphor component is diffused into the glass to color the glass, resulting in a decrease in luminescence intensity.

Further, the baking is preferably carried out in a reduced pressure environment. Specifically, the environment in the calcination is preferably less than 1.013 × 10 ⁵ Pa, more preferably 1,000 Pa or less, still more preferably 400 Pa or less. Thereby, the amount of bubbles remaining in the wavelength converting member can be reduced. As a result, the scattering factor in the wavelength conversion member can be reduced, and the luminous efficiency can be improved. Furthermore, the calcination step may be carried out as a whole in a reduced pressure environment, or, for example, only the calcination step may be carried out in a reduced pressure environment, and the temperature rise step or the temperature decrease step before and after the step may be performed in an environment other than a reduced pressure environment (for example, at atmospheric pressure). )get on.

The shape of the wavelength conversion member of the present invention is not particularly limited, and includes, for example, a member having a specific shape such as a plate shape, a column shape, a hemispherical shape, or a hemispherical dome shape, and a substrate formed on a glass substrate or a ceramic substrate. A sintered body such as a film on the surface.

Fig. 1 shows an embodiment of a light-emitting device of the present invention. As shown in FIG. 1, the light-emitting device 1 is provided with a wavelength conversion member 2 and a light source 3. The light source 3 irradiates the wavelength conversion member 2 with the excitation light L1. The excitation light L1 incident on the wavelength conversion member 2 is converted into the fluorescence L2 of the other wavelength, and is emitted from the side opposite to the light source 3. At this time, the combined light of the excitation light L1 and the fluorescent light L2 that have not been converted by the wavelength conversion can be emitted.

[Examples]

Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to the examples.

(1) Production of glass powder

Tables 1 and 2 show the glass powders (samples A to M) used in the examples and the glass powders (samples N to P) used in the comparative examples.

First, raw materials were prepared in such a manner as to have the composition of the glasses shown in Tables 1 and 2. The raw material is melted at a temperature of 800 to 1500 ° C for 1 to 2 hours using a platinum crucible to vitrify, and the molten glass is allowed to flow out between a pair of cooling rolls to form a film. The film-shaped glass molded body was pulverized by a ball mill, and classified to obtain a glass powder having an average particle diameter D ₅₀ of 2.5 μm. The softening point and weather resistance of the obtained glass powder were measured by the following methods.

The softening point is a fiber elongation method and a viscosity of 10 ^7.6 dPa ‧ is used.

Weather resistance was evaluated in the following manner. The glass powder was pressure-molded by a mold to prepare a cylindrical preform having a diameter of 1 cm, and the calcination described in Tables 1 and 2 was carried out. The calcination was carried out at a temperature, whereby a cylindrical sintered body sample was obtained. The sample was held at 121 ° C, 95% RH, and 2 atm for 300 hours using a HAST tester PC-242HSR2 manufactured by Hirayama Seisakusho Co., Ltd., and the surface of the sample was observed to evaluate the weather resistance. Specifically, when observed by an optical microscope (×500), the change in the surface of the sample before and after the test was evaluated as “○”, and the glass component or the tarnish was precipitated on the surface of the sample as “×”.

(2) Production of wavelength conversion member

Tables 3 to 6 show examples (samples 1 to 13, 17 to 29) and comparative examples (14 to 16, 30 to 32) of the present invention.

The inorganic phosphor powders shown in Tables 3 to 6 were mixed in a specific mass ratio to each of the glass powder samples described in Tables 1 and 2 to obtain a mixed powder. The mixed powder was subjected to pressure molding using a mold to prepare a cylindrical preform having a diameter of 1 cm. After the preform was fired, the obtained sintered body was processed to obtain a disk-shaped wavelength conversion member having a diameter of 8 mm and a thickness of 0.2 mm. Further, the calcination temperature is the calcination temperature described in Tables 1 and 2 depending on the glass powder to be used. The luminescence spectrum was measured for the obtained wavelength conversion member, and the luminescence efficiency was calculated. The results are shown in Tables 3 to 6.

The luminous efficiency was obtained in the following manner. First, a wavelength conversion member is provided on a light source having an excitation wavelength of 460 nm, and an energy distribution spectrum of light emitted from a surface of the wavelength conversion member is measured in an integrating sphere. Next, the obtained spectrum is multiplied by the standard specific visual sensitivity to calculate the total luminous flux, and the total luminous flux is divided by the electric power of the light source to calculate the luminous efficiency.

Next, the wavelength conversion member was processed into a 1.2 mm square to obtain a small-wavelength conversion member. The small-wavelength conversion member was placed on an LED wafer having an emission wavelength of 445 nm energized at 650 mA, and subjected to continuous light irradiation for 100 hours. For the wavelength conversion member before the light irradiation and after 100 hours of the light irradiation, the energy distribution spectrum of the light emitted from the upper surface of the wavelength conversion member was measured in the integrating sphere using a general-purpose luminescence spectrometer. The total luminous flux value is calculated by multiplying the obtained luminescence spectrum by a standard specific luminosity. The rate of change of the total luminous flux value is expressed by the value (%) obtained by dividing the total luminous flux value after 100 hours of light irradiation by the total luminous flux value before light irradiation and multiplying by 100, and is shown in Tables 3 to 6.

As is clear from Tables 3 and 4, in the case where α-SiAlON is used as the inorganic phosphor, the total luminous flux value after 100 hours of light irradiation as the wavelength conversion member of Examples 1 to 13 is maintained at 98% before the light irradiation. On the other hand, in the wavelength conversion members of 14 to 16 which are comparative examples, the total luminous flux value after light irradiation for 100 hours is greatly reduced to 96.5% or less before the light irradiation.

As is clear from Tables 5 and 6, when YAG was used as the inorganic phosphor, the wavelength conversion members of Examples 17 to 29 did not confirm the decrease in the total luminous flux value even after 100 hours of light irradiation. In the wavelength conversion member of 30 to 32 which is a comparative example, the total luminous flux value after light irradiation for 100 hours is greatly reduced to 98.5% or less before light irradiation.

[Industrial availability]

The wavelength conversion member of the present invention is suitable as a constituent member of general illumination such as a white LED or special illumination (for example, a projector light source or a headlight source of an automobile).

Claims (6)

A wavelength conversion member characterized in that it is obtained by dispersing an inorganic phosphor in a glass matrix, and the glass substrate contains 40 to 60% of SiO _{2 and} 0.1 to 35% of B ₂ O _{3 in terms of} mol%; Al ₂ O ₃ 0.1~10%, Li ₂ O 0~10%, Na ₂ O 0~10%, K ₂ O 0~10%, Li ₂ O+Na ₂ O+K ₂ O 0.1~10%, MgO 0~45%, CaO 0~45%, SrO 0~45%, BaO 0~45%, MgO+CaO+SrO+BaO 0.1~45%, and ZnO 0~15%, and the above inorganic fluorescent system is selected from Oxide phosphor, nitride phosphor, oxynitride phosphor, chloride phosphor, oxychloride phosphor, halide phosphor, aluminate phosphor, and halophosphate phosphor At least one of the group consisting of bodies. The wavelength conversion member according to claim 1, wherein the glass substrate contains 0.1% or more of Li ₂ O, Na ₂ O, and K ₂ O, respectively. The wavelength conversion member according to claim 1 or 2, wherein the glass substrate has a softening point of 400 to 800 °C. The wavelength conversion member according to any one of claims 1 to 3, which contains 0.01 to 30% by mass of the above inorganic phosphor. The wavelength conversion member according to any one of claims 1 to 4, which comprises a powder sintered body. A light-emitting device comprising the wavelength conversion member according to any one of claims 1 to 5, and a light source that irradiates the wavelength conversion member with excitation light.