JP2022063277A - Glass for use in wavelength conversion material, wavelength conversion material, wavelength conversion member, and light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass which can be used in a wavelength conversion material containing a phosphor, is less likely to undergo the deterioration in properties of the phosphor upon firing in the production of a wavelength conversion member, and makes it possible to produce a wavelength conversion member having excellent weather resistance.

SOLUTION: A glass can be used in a wavelength conversion material, and is characterized by containing, in mass%, 30 to 75% of SiO₂, 1 to 30% of B₂O₃, more than 4% and up to 20% of Al₂O₃, 0.1 to 10% of Li₂O, 0% and less than 9% of Na₂O+K₂O, and 0 to 10% of MgO+CaO+SrO+BaO+ZnO.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a glass used for manufacturing a wavelength conversion member that converts the wavelength of light emitted by a light emitting diode (LED: Light Emitting Diode), a laser diode (LD: Laser Diode), or the like into another wavelength. ..

In recent years, as a next-generation light source that replaces fluorescent lamps and incandescent lamps, attention has been increasing to light sources using LEDs and LDs. As an example of such a next-generation light source, for example, in Patent Document 1, a light source in which a wavelength conversion member that absorbs a part of light from an LED and converts it into yellow light is arranged on an LED that emits blue light. Is disclosed. This light source emits white light, which is a composite light of blue light emitted from an LED and yellow light emitted from a wavelength conversion member.

Conventionally, as the wavelength conversion member, a member in which a phosphor is dispersed in a resin matrix has been used. However, when the wavelength conversion member is used, there is a problem that the resin is deteriorated by the light from the LED and the brightness of the light source tends to be lowered. In particular, there is a problem that the mold resin is deteriorated by the heat generated by the LED or the phosphor and the high-energy short-wavelength (ultraviolet) light, causing discoloration or deformation.

Therefore, a wavelength conversion member made of a completely inorganic solid in which a phosphor is dispersed and fixed in a glass matrix instead of a resin has been proposed (see, for example, Patent Documents 2 and 3). The wavelength conversion member has a feature that the glass as a base material is less likely to be deteriorated by the heat of the LED chip or the irradiation light, and problems such as discoloration and deformation are less likely to occur.

Japanese Unexamined Patent Publication No. 2000-208815 Japanese Unexamined Patent Publication No. 2003-258308 Japanese Patent No. 4895541

The wavelength conversion member has a problem that the phosphor is deteriorated by firing at the time of manufacturing and the brightness is easily deteriorated. In particular, in applications such as general lighting and special lighting, high color rendering properties are required, so it is necessary to use a red phosphor having relatively low heat resistance, and the deterioration of the phosphor tends to be remarkable.

On the other hand, if low softening point glass capable of low temperature sintering is used in order to solve the above problem, there is a problem that the use as the wavelength conversion member is limited because the weather resistance of the obtained wavelength conversion member is inferior. ..

Therefore, the present invention is a glass used as a wavelength conversion material containing a phosphor, and a wavelength conversion member having less deterioration in the characteristics of the phosphor due to firing during manufacturing of the wavelength conversion member and having excellent weather resistance is produced. The purpose is to provide a glass that can be made.

The glass of the present invention is a glass used as a wavelength conversion material, and in terms of mass%, SiO ₂ 30 to 75%, B ₂ O ₃ 1 to 30%, Al ₂ O ₃ 4 or more to 20%, Li ₂ O. It is characterized by containing 0.1 to 10%, Na ₂ O + K ₂ O 0 to less than 9%, and MgO + CaO + SrO + BaO + ZnO 0 to 10%. Here, "Na ₂ O + K ₂ O" means the total amount of each content of Na ₂ O and K ₂ O, and "MgO + CaO + SrO + BaO + ZnO" means the total amount of each content of MgO, CaO, SrO, BaO and ZnO. Means.

Since the glass of the present invention contains Li ₂ O in an amount of 0.1% by mass or more as described above, it is easy to achieve a low softening point. Therefore, low-temperature sintering is possible, and thermal deterioration of the fluorophore powder can be suppressed. Further, since the glass contains 30% by mass or more of SiO ₂ , the glass has excellent weather resistance, and the wavelength conversion member is less likely to deteriorate with time. Furthermore, by limiting the content of SiO ₂ that enhances the transmittance in the ultraviolet region to 30% by mass or more and the content of the alkaline component that reduces the transmittance in the ultraviolet region to less than 19% by mass, the light transmittance is high in the ultraviolet region. Can be achieved.

The glass of the present invention preferably contains substantially no lead component or arsenic component.

Since the lead component and the arsenic component are environmentally hazardous substances, the glass powder can be an environmentally preferable wavelength conversion member by having a structure that does not substantially contain these components. In addition, "substantially not contained" means that the glass is intentionally not contained, and does not mean that unavoidable impurities are completely eliminated. Objectively, it means that the content of these components including impurities is less than 0.05% by mass, respectively.

The glass of the present invention further preferably contains ZrO ₂₀ to 10% and F ₂₀ to 5% by mass.

The glass of the present invention preferably has a softening point of 750 ° C. or lower.

The glass of the present invention preferably has a coloring degree λ ₈₀ of 400 nm or less.

In the present invention, the degree of coloration λ ₈₀ means the shortest wavelength at which the light transmittance is 80% in the light transmittance curve measured using a sample having a thickness of 10 mm.

The glass of the present invention is preferably in the form of powder.

The wavelength conversion material of the present invention is characterized by containing the above glass and a phosphor.

In the wavelength conversion material of the present invention, the fluorescent substance is a nitride fluorescent substance, an oxynitride phosphor, an oxide fluorescent substance, a sulfide fluorescent substance, an acid sulfide fluorescent substance, a halide fluorescent substance, an aluminate fluorescent substance, and the like. Barium magnesium aluminate-based fluorescent material, calcium halophosphate-based fluorescent material, alkaline earth chlorobolate-based fluorescent material, alkaline earth aluminate-based fluorescent material, alkaline earth silicon oxynitride-based fluorescent material, alkaline earth magnesium silicate-based fluorescent material It is preferably one or more selected from the body, alkaline earth silicon nitride type fluorescent material and rare earth oxycalyugenite type fluorescent material.

The wavelength conversion member of the present invention is characterized by being made of a sintered body of the wavelength conversion material.

The wavelength conversion member of the present invention is a wavelength conversion member in which a phosphor is dispersed in a glass matrix, and the glass matrix has a mass% of SiO ₂ 30 to 75%, B ₂ O ₃ 1 to 30%, and the like. It is characterized by containing Al ₂ O 34 more than 20%, Li ₂ O 0.1 to 10%, Na ₂ O + K ₂ O ₀ to less than 9%, and MgO + CaO + SrO + BaO + ZnO 0 to 10%.

The light emitting device of the present invention is characterized by comprising the wavelength conversion member and a light source for irradiating the wavelength conversion member with excitation light.

According to the present invention, a glass used as a wavelength conversion material containing a phosphor, which has little deterioration in the characteristics of the phosphor due to firing during manufacturing of the wavelength conversion member and has excellent weather resistance, is produced. It is possible to provide a glass that can be used.

It is a schematic side view of the light emitting device which concerns on one Embodiment of this invention.

The glass of the present invention is used as a wavelength conversion material, and in mass%, SiO ₂ 30 to 75%, B ₂ O ₃ 1 to 30%, Al ₂ O ₃ 4 or more to 20%, Li ₂ O 0. .1 to 10%, Na ₂ O + K ₂ O 0 to less than 9%, MgO + CaO + SrO + BaO + ZnO 0 to 10%. Since glass containing the composition can be fired at a low temperature, the fluorescent substance is less likely to deteriorate and react with the phosphor when fired together with the phosphor. Further, since the wavelength conversion member obtained by using the glass is excellent in weather resistance and light transmittance in the ultraviolet region, the degree of freedom in designing a light emitting device using the wavelength conversion member can be expanded. Moreover, a highly reliable light emitting device can be manufactured.

The reason for limiting the glass composition range as described above will be described below. In the following description of the content of each component, "%" means "mass%" unless otherwise specified.

SiO ₂ is a component that forms a glass network, and is a component that remarkably enhances the light transmittance in the ultraviolet region to the visible region. Especially in the case of glass having a high refractive index, the effect of increasing the light transmittance can be easily obtained. It is also a component that improves weather resistance. The content of SiO ₂ is 30 to 75%, preferably 35 to 70%, 40 to 65%, 45 to 62.5%, and particularly preferably 45 to 60%. If the content of SiO ₂ is too small, it becomes difficult to obtain the above effect. On the other hand, if the content of SiO ₂ is too large, the sintering temperature becomes high, and the phosphor tends to deteriorate during firing.

B ₂ O ₃ is a component that forms a glass network and is a component that enhances the light transmittance in the ultraviolet to visible range. Especially in the case of glass having a high refractive index, the effect of increasing the light transmittance can be easily obtained. The content of B ₂ O ₃ is 1 to 30%, preferably 1.5 to 27.5%, 2 to 25%, and particularly preferably 2.5 to 20%. If the content of B ₂ O ₃ is too small, it becomes difficult to obtain the above effect. On the other hand, if the content of B ₂ O ₃ is too large, the sintering temperature becomes high and the phosphor tends to deteriorate during firing.

Al ₂ O ₃ is a component that forms a glass network and is a component that enhances the light transmittance in the ultraviolet to visible range. Especially in the case of glass having a high refractive index, the effect of increasing the light transmittance can be easily obtained. The content of Al ₂ O ₃ is more than 4 to 20%, preferably 5 to 18%, 6 to 16%, and particularly preferably 7 to 14%. If the content of Al ₂ O ₃ is too small, it becomes difficult to obtain the above effect. On the other hand, if the content of Al ₂ O ₃ is too large, the sintering temperature becomes high and the phosphor tends to deteriorate during firing.

Li ₂ O is a component that significantly lowers the softening point. The content of Li ₂ O is 0.1 to 10%, preferably 0.5 to 7.5%, particularly preferably 1 to 5%. If the content of Li ₂ O is too small, it becomes difficult to obtain the above effect. On the other hand, if the content of Li ₂ O is too large, the weather resistance and the refractive index tend to decrease, and the light transmittance tends to decrease.

Na ₂ O and K ₂ O are components that lower the softening point. The content of Na ₂ O + K ₂ O is preferably 0 to less than 9%, 0.5 to 8%, and particularly preferably 1 to 7%. If the content of Na ₂ O + K ₂ O is too large, the weather resistance and the refractive index tend to decrease, and the light transmittance tends to decrease.

The range of Na ₂ O and K ₂ O contents is as follows.

The content of Na ₂ O is preferably 0 to less than 9%, 0.5 to 7.5%, and particularly preferably 1 to 5%.

The content of K2O is preferably ₀ to less than 9%, 0.5 to 7.5%, and particularly preferably 1 to 5%.

MgO, CaO, SrO, BaO and ZnO are components that act as a flux. It also has the effect of suppressing devitrification and improving weather resistance. The content of MgO + CaO + SrO + BaO + ZnO is 0 to 10%, preferably 0.1 to 9%, 0.5 to 8%, 1 to 7%, 1.5 to 6%, and particularly preferably 2 to 5%. If the content of MgO + CaO + SrO + BaO + ZnO is too large, devitrification is likely to occur during molding or sintering. In addition, the light transmittance tends to decrease.

The range of the contents of MgO, CaO, SrO, BaO and ZnO is as follows.

The content of MgO is preferably 0 to 10%, 0.1 to 9%, 0.5 to 8%, 1 to 7%, 1.5 to 6%, and particularly preferably 2 to 5%.

The CaO content is preferably 0 to 10%, 0.1 to 9%, 0.5 to 8%, 1 to 7%, 1.5 to 6%, and particularly preferably 2 to 5%.

The content of SrO is preferably 0 to 10%, 0.1 to 9%, 0.5 to 8%, 1 to 7%, 1.5 to 6%, and particularly preferably 2 to 5%.

The content of BaO is preferably 0 to 10%, 0.1 to 9%, 0.5 to 8%, 1 to 7%, 1.5 to 6%, and particularly preferably 2 to 5%.

The ZnO content is preferably 0 to 10%, 0.1 to 9%, 0.5 to 8%, 1 to 7%, 1.5 to 6%, and particularly preferably 2 to 5%.

The glass of the present invention may contain the following components in addition to the above components.

ZrO ₂ is a component that improves weather resistance and a component that enhances the refractive index. The content of ZrO ₂ is preferably 0 to 10%, 0.1 to 7.5%, 0.25 to 5%, and particularly preferably 0.5 to 3%. If the content of ZrO ₂ is too large, the softening point tends to increase, the devitrification resistance deteriorates, and the liquidus viscosity tends to decrease.

F ₂ is a component that lowers the softening point. In addition, it is a component that remarkably enhances the light transmittance in the ultraviolet region. The content of F ₂ is preferably 0 to 5%, 0.1 to 4.5%, and particularly preferably 0.3 to 4%. If the content of F ₂ is too large, the weather resistance and devitrification resistance tend to deteriorate.

Nb ₂ O ₅ is a component that improves weather resistance and a component that enhances the refractive index. The content of Nb ₂ O ₅ is preferably 0 to 20%, 0.1 to 15%, 0.5 to 10%, and particularly preferably 1 to 5%. If the content of Nb ₂ O ₅ is too large, the softening point tends to increase and the light transmittance tends to decrease.

La ₂ O ₃ is a particularly effective component for obtaining high refractive index characteristics. The content of La ₂ O ₃ is preferably 0 to 20%, 0.1 to 15%, 0.5 to 10%, and particularly preferably 1 to 5%. If the content of La ₂ O ₃ is too large, the softening point tends to increase, the devitrification resistance deteriorates, and the liquidus viscosity tends to decrease.

WO ₃ is a component that increases the refractive index. The content of WO ₃ is preferably 0 to 20%, 0.1 to 15%, 0.5 to 10%, and particularly preferably 1 to 5%. If the content of WO ₃ is too large, the softening point tends to increase and the light transmittance tends to decrease.

Y ₂ O ₃ has the effect of increasing the refractive index and improving the weather resistance. The content of Y ₂ O ₃ is preferably 0 to 5%, 0 to 4%, 0 to 3%, and particularly preferably 0.1 to 2%. If the content of _Y2O3 is too large _, the glass is colored and the light transmittance is lowered, and the liquidus viscosity is likely to be lowered.

When TiO ₂ contains a large amount of Fe component as an impurity in the glass (for example, 20 ppm or more), the light transmittance tends to be remarkably lowered, and the softening point tends to increase. Therefore, the content of TiO ₂ is preferably 1% or less, 0.5% or less, and particularly preferably 0.1% or less.

For environmental reasons, it is preferable to avoid introducing lead components (PbO, etc.) and arsenic components (As ₂ O ₃ , etc.) into glass. Therefore, it is preferable that these components are not substantially contained.

The softening point of the glass of the present invention is preferably 750 ° C. or lower, 748 ° C. or lower, and particularly preferably 745 ° C. or lower. If the softening point is too high, the sintering temperature of the wavelength conversion material containing the glass and the phosphor of the present invention becomes high, so that the phosphor is likely to deteriorate during firing. The lower limit of the softening point is not particularly limited, but if it is too low, the weather resistance tends to deteriorate. Therefore, the softening point is preferably 400 ° C. or higher, more preferably 450 ° C. or higher, and even more preferably 500 ° C. or higher.

The degree of coloration λ ₈₀ of the glass of the present invention is preferably 400 nm or less, 380 nm or less, and particularly preferably 360 nm or less. If the degree of coloring λ ₈₀ is too large, the light transmittance in the ultraviolet region to the visible region tends to be inferior. As a result, the amount of excitation light irradiated to the phosphor powder is reduced, and it becomes difficult to obtain emitted light having a desired hue from the wavelength conversion member.

The coefficient of thermal expansion (30 to 300 ° C.) of the glass of the present invention is 30 × ^10-7 to 120 × ^10-7 / ° C, 40 × ^10-7 to 110 × ^10-7 / ° C, especially 50 × ^10-7 to It is preferably 100 × 10 ^-7 / ° C. If the coefficient of thermal expansion is too low or too high, the coefficient of thermal expansion of the base material for fixing the wavelength conversion member and the adhesive material for adhering the wavelength conversion member and the base material will not match, and the temperature will be high. Cracks are likely to occur when used in.

In general, a fluorescent substance often has a higher refractive index than glass. In the wavelength conversion member, if the difference in refractive index between the phosphor and the glass matrix is large, the excitation light is likely to be scattered at the interface between the phosphor and the glass matrix. As a result, the irradiation efficiency of the excitation light to the phosphor is increased, and the luminous efficiency is likely to be improved. However, if the difference in refractive index between the phosphor and the glass matrix is too large, the excitation light is excessively scattered, resulting in scattering loss and conversely, the luminous efficiency tends to decrease. In view of the above, the refractive index (nd) of the glass of the present invention is 1.4 to 1.8, more preferably 1.42 to 1.75, and even more preferably 1.45 to 1.7. The difference in refractive index between the phosphor and the glass matrix is preferably about 0.001 to 0.5.

Next, an example of the method for producing glass of the present invention will be described.

First, a glass raw material is prepared so as to have a desired composition, and then melted in a glass melting furnace. In order to obtain a homogeneous glass, the melting temperature is preferably 1150 ° C. or higher, 1200 ° C. or higher, and particularly preferably 1250 ° C. or higher. From the viewpoint of preventing glass coloring due to Pt melting from the platinum metal constituting the melting container, the melting temperature is preferably 1450 ° C. or lower, 1400 ° C. or lower, 1350 ° C. or lower, and particularly preferably 1300 ° C. or lower.

Further, if the melting time is too short, a homogeneous glass may not be obtained. Therefore, the melting time is preferably 30 minutes or more, particularly preferably 1 hour or more. However, from the viewpoint of preventing glass coloring due to Pt melting from the melting container, the melting time is preferably 8 hours or less, particularly preferably 5 hours or less.

The molten glass may be poured into a mold and formed into a plate shape, or may be poured between a pair of cooling rollers and formed into a film shape. To obtain glass powder, glass formed into a plate or film is crushed with a ball mill or the like.

In the case of powdery glass, by mixing it with a powdery phosphor and firing it, it becomes possible to easily produce a wavelength conversion member in which the phosphor is uniformly dispersed in the glass matrix.

When the glass of the present invention is in the form of powder (that is, glass powder), its particle size is not particularly limited, but for example, the maximum particle size Dmax is 200 μm or less (particularly 150 μm or less, further 105 μm or less), and the average particle size. It is preferable that D50 is 0.1 μm or more (particularly 1 μm or more, further 2 μm or more). If the maximum particle diameter Dmax 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 likely to decrease. Further, if the average particle diameter D50 is too small, the excitation light is excessively scattered in the obtained wavelength conversion member, and the luminous efficiency tends to decrease.

In the present invention, the maximum particle diameter Dmax and the average particle diameter D50 refer to the values measured by the laser diffraction method.

The glass of the present invention is used as a wavelength conversion material in combination with a phosphor.

The fluorescent substance is not particularly limited as long as it is generally available on the market. For example, nitride phosphors, oxynitride phosphors, oxide phosphors (including garnet-based phosphors such as YAG phosphors), sulfide phosphors, acid sulfide phosphors, and halide phosphors (halophosphate formation). Phosphorus, etc.), Aluminate Fluorescent, Barium Magnesium Aluminate Fluorescent, Calcium Halophosphate Fluorescent, Alkaline Earth Chlorobolate Fluorescent, Alkaline Earth Aluminate Fluorescent, Alkaline Earth Silicon Oxinite Examples thereof include a ride-based fluorescent substance, an alkaline earth magnesium silicate-based fluorescent substance, an alkaline earth silicon nitride-based fluorescent substance, and a rare earth oxycalyugenite-based fluorescent substance. These fluorophores are usually in powder form. Of these fluorescent materials, the nitride fluorescent material, the oxynitride fluorescent material, and the oxide fluorescent material are preferable because they have high heat resistance and are relatively resistant to deterioration during firing. The nitride phosphor and the oxynitride phosphor have a feature that the excitation light of near-ultraviolet to blue is converted into a wide wavelength region of green to red, and the emission intensity is relatively high. Therefore, the nitride phosphor and the oxynitride phosphor are particularly effective as phosphors used in wavelength conversion members for white LED elements.

The phosphor has an excitation band at a wavelength of 300 to 500 nm and an emission peak at a wavelength of 380 to 780 nm, particularly blue (wavelength 440 to 480 nm), green (wavelength 500 to 540 nm), and yellow (wavelength 540 to 595 nm). ) Or those that emit light in red (wavelength 600 to 700 nm).

Examples of the phosphor that emits blue light when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm include (Sr, Ba) MgAl ₁₀ O ₁₇ : Eu ²⁺ , (Sr, Ba) ₃ MgSi ₂ O ₈ : Eu. ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , (Ca, Sr, Ba) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , (Ca, Sr, Ba) ₂ B ₅ O ₉ Cl: Eu ²⁺ , LaAl (Si _{6- z} Al _z ) N _{10-z Oz} : Ce ³⁺ , (Sr _1-x , Ba _x ) Al ₂ Si ₃ O ₄ N ₄ : Eu ²⁺ and the like.

Examples of the phosphor that emits blue-green light when irradiated with ultraviolet-near-ultraviolet excitation light having a wavelength of 300 to 440 nm include (Sr, Ca, Ba) Al ₂ O ₄ : Eu ²⁺ , (Sr, Ca, Ba) ₄ Al. ₁₄ O ₂₅ : Eu ²⁺ and the like can be mentioned.

SrAl ₂ O ₄ : Eu ²⁺ , SrBaSiO ₄ : Eu ²⁺ , Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ³⁺ , SrSiO _n : 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⁺ , (Mg, Ca, Sr, Ba) Si ₂ O ₂ N ₂ : Eu ²⁺ , (Ba, Ca, Sr) ₂ SiO ₄ : Eu ²⁺ and the like.

Examples of the phosphor that emits red fluorescence when irradiated with ultraviolet-near-ultraviolet excitation light having a wavelength of 300 to 440 nm include (Mg, Ca, Sr, Ba) ₂ Si ₅ N ₈ : Eu ²⁺ , (Y, La, Gd, Lu) ₂ O ₂ S: Eu ²⁺ and the like.

Examples of phosphors that emit 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⁺ , Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ³⁺ , Examples thereof include SrSiOn: Eu ²⁺ and β-SiAlON: Eu ²⁺ .

Examples of the phosphor that emits yellow fluorescence when irradiated with ultraviolet-near-ultraviolet excitation light having a wavelength of 300 to 440 nm include La ₃ Si ₆ N ₁₁ : Ce ³⁺ and the like.

Examples of the phosphor that emits yellow fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm include Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ³⁺ and Sr ₂ SiO ₄ : Eu ²⁺ .

CaGa ₂ S ₄ : Mn ²⁺ , MgSr ₃ Si ₂ O ₈ : Eu ²⁺ , Mn ²⁺ , Ca ₂ MgSi ₂ are examples of phosphors that emit red fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light with a wavelength of 300 to 440 nm. O ₇ : Eu ²⁺ , Mn ²⁺ and the like can be mentioned.

Examples of phosphors that emit 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⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ²⁺ , α-. SiAlON: Eu ²⁺ and the like.

A plurality of phosphors may be mixed and used according to the wavelength range of the excitation light or the emission. For example, when white light is obtained by irradiating excitation light in the ultraviolet region, a phosphor that emits blue, green, yellow, and red fluorescence may be mixed and used.

If the content of the phosphor in the wavelength conversion member is too large, problems such as difficulty in efficiently irradiating the phosphor with excitation light and a tendency to reduce the mechanical intensity occur. On the other hand, if the content of the phosphor is too small, it becomes difficult to obtain a desired emission intensity. From this point of view, the content of the phosphor in the wavelength conversion member is mass%, preferably 0.01 to 50%, more preferably 0.05 to 40%, still more preferably 0.1 to 30%. Adjusted in range.

In the wavelength conversion member whose purpose is to reflect the fluorescence generated in the wavelength conversion member to the side where the excitation light is incident and mainly extract only the fluorescence to the outside, the emission intensity is maximized, not limited to the above. As described above, the content of the phosphor can be increased (for example, 50% to 80% by mass, and further 55 to 75%).

The wavelength conversion member of the present invention is not particularly limited as long as it is formed by sealing a phosphor in glass. For example, those composed of a sintered body of glass powder and phosphor powder can be mentioned. Alternatively, a fluorescent substance may be sandwiched between a plurality of (for example, two) glass plates. In this case, it is preferable that the plurality of glass plates are fused to each other at the peripheral edge or sealed with a sealing material such as a glass frit.

The sintered body of glass powder and phosphor powder can be produced by roll press molding. Specifically, after the glass powder and the phosphor powder are mixed to obtain a mixed powder, the mixed powder is put into a pair of heating roller gaps. Inorganic filler may be mixed in the mixed powder for the purpose of improving mechanical strength and the like. The mixed powder is extruded in the direction of rotation of the roller while being heated and pressed by the roller. As a result, the mixed powder is formed into a sheet. According to this molding method, since the heating time is short, thermal deterioration of the phosphor can be suppressed. Further, by passing the mixed powder between the heating rollers, the glass powder is softened and crushed, so that a dense sheet-shaped wavelength conversion member can be easily obtained. When a nanoparticle phosphor is used as the phosphor, since the phosphor particle size is small, the contact resistance of the phosphor particles to the roller is small, so that the moldability is easily improved. Further, since the contact resistance between the glass powder and the phosphor particles is also reduced, the adhesion (sinterability) between the glass powders is likely to be improved.

The size of the gap between the rollers can be appropriately set according to the thickness of the target sheet. The rotation speed of the roller can be appropriately set according to the type of the mixed powder, the temperature of the roller, and the like.

The molding step can be performed, for example, in an atmosphere of air, nitrogen or argon. From the viewpoint of suppressing deterioration of the characteristics of the glass powder or the phosphor, it is preferable to perform molding in an inert gas such as nitrogen or argon. Further, molding may be performed in a reduced pressure atmosphere. By performing the molding in a reduced pressure atmosphere, it is possible to suppress the residual bubbles in the wavelength conversion member.

The method for producing a sintered body of glass powder and ultraviolet luminescent phosphor powder is not limited to roll press molding. Specifically, a wavelength conversion material can be obtained by mixing glass powder and ultraviolet luminescent phosphor powder to obtain a mixed powder and then firing the powder. The firing temperature is preferably equal to or higher than the softening point of the glass powder. This makes it possible to form a glass matrix formed by fusing glass powder. On the other hand, if the firing temperature is too high, the inorganic ultraviolet luminescent phosphor powder elutes into the glass and the emission intensity decreases, or the components contained in the inorganic ultraviolet luminescent phosphor powder diffuse into the glass and the glass is colored. , The emission intensity may decrease. Therefore, the firing temperature is preferably a softening point of the glass powder + 150 ° C. or lower, and more preferably a softening point of the glass powder + 100 ° C. or lower.

Baking is preferably performed in a reduced pressure atmosphere. Specifically, the calcination is preferably carried out in an atmosphere of less than ^1.013 × 105 Pa, more preferably 1000 Pa or less, still more preferably 400 Pa or less. Thereby, the amount of bubbles remaining in the wavelength conversion 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. The entire firing step may be performed in a reduced pressure atmosphere, or only the firing step may be performed in a reduced pressure atmosphere, and the temperature raising step and the temperature lowering step before and after the firing step may be performed in an atmosphere other than the reduced pressure atmosphere (for example, under atmospheric pressure). You may.

The shape of the wavelength conversion member of the present invention is not particularly limited, and is not limited to a member having a specific shape itself such as a plate shape, a columnar shape, a spherical shape, a hemispherical shape, a hemispherical shape, etc. It may be in the form of a film formed on the surface of the base material of.

The wavelength conversion member obtained as described above is a wavelength conversion member in which a phosphor is dispersed in a glass matrix, and the glass matrix has a mass% of SiO ₂ 30 to 75% and B ₂ O ₃ . It contains 1 to 30%, Al ₂ O ₃ 4 to 20%, Li ₂ O 0.1 to 10%, Na ₂ O + K ₂ O 0 to less than 9%, MgO + CaO + SrO + BaO + ZnO 0 to 10%.

FIG. 1 shows an embodiment of the light emitting device of the present invention. As shown in FIG. 1, the light emitting device 1 includes a wavelength conversion member 2 and a light source 3. The light source 3 irradiates the wavelength conversion member 2 with the excitation light _Lin of the phosphor powder. The excitation light Lin incident on the wavelength conversion member 2 is converted into light having a different wavelength, and is _emitted as L _out from the side opposite to the light source 3. At this time, the combined light of the light after the wavelength conversion and the excitation light transmitted without the wavelength conversion may be emitted.

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

(1) Preparation of glass Tables 1 to 3 show the glass according to Examples (samples a to m) and Comparative Examples (samples x and y).

First, the raw materials were prepared so as to have the compositions shown in Tables 1 to 3. The raw material was melted in a platinum crucible at 1300 ° C. for 2 hours to vitrify it, and the molten glass was poured between a pair of cooling rollers to form a film. The film-shaped glass was pulverized with a ball mill and then classified to obtain a glass powder having an average particle size D50 of 2.5 μm. In addition, a plate-shaped sample suitable for each measurement was prepared by casting a part of the molten glass into a carbon mold.

The obtained sample was evaluated for refractive index (nd), softening point, degree of coloring, coefficient of thermal expansion (30 to 300 ° C.) and weather resistance. The results are shown in the table.

The refractive index is shown as a measured value for the d-line (587.6 nm) of the helium lamp.

For the softening point, a fiber elongation method was used, and a temperature at which the viscosity was ^107.6 dPa · s was adopted.

The degree of coloring was measured as follows. For an optically polished sample having a thickness of 10 mm ± 0.1 mm, the light transmittance in the wavelength range of 200 to 800 nm was measured at intervals of 0.5 nm using a spectrophotometer, and a light transmittance curve was prepared. In the light transmittance curve, the shortest wavelength showing the light transmittance of 80% was defined as the coloring degree λ ₈₀ .

The coefficient of thermal expansion (30 to 300 ° C.) was measured using a thermal expansion measuring device (dirato meter).

For weather resistance, a disk-shaped evaluation sample having a diameter of 8 mm and a thickness of 1 mm was held for 300 hours under the conditions of 121 ° C., 95% RH, and 2 atm using a HAST testing machine PC-242HSR2 manufactured by Hirayama Seisakusho. It was evaluated by observing the sample surface. Specifically, by microscopic observation before and after the test, those with no change in the sample surface were evaluated as "○", and those with glass components precipitated or lost gloss were evaluated as "×". .. The evaluation sample was prepared by pressure-molding the glass powder with a mold, firing at a temperature 20 ° C. lower than the softening points shown in Tables 1 to 3, and then performing processing such as cutting and polishing.

As shown in Tables 1 to 3, the samples a to m of Examples were excellent in each characteristic. On the other hand, the sample x as a comparative example had a high softening point of 785 ° C. Further, the sample y was inferior in weather resistance, and the degree of coloring λ ₈₀ was as large as 420 nm. (2) Preparation of Wavelength Converting Member Tables 4 to 6 show the wavelength conversion member according to Examples (No. 1 to 13) and Comparative Example (No. 14).

BaMgAl ₁₀ O ₁₇ : Eu ²⁺ or α-SiAlON as a fluorescent substance powder is mixed with each of the glass powder samples shown in Tables 1 to 3 so that the glass powder: fluorescent substance powder = 80:20 (mass ratio). Obtained a raw material powder for a wavelength conversion member. The raw material powder was pressure-molded with a mold to prepare a columnar premolded body having a diameter of 1 cm. This preformed body was fired at a temperature of + 30 ° C. at the softening point of the glass powder, and then 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. .. The emission spectrum of the obtained wavelength conversion member was measured, and the luminous efficiency was calculated. The results are shown in Tables 4-6.

Luminous efficiency was determined as follows. A wavelength conversion member was placed on a light source having an excitation wavelength of 405 nm or 460 nm, and the energy distribution spectrum of light emitted from the upper surface of the sample was measured in the integrating sphere. Next, the total luminous flux was calculated by multiplying the obtained spectrum by the standard luminosity factor, and the total luminous flux was divided by the power of the light source to calculate the luminous efficiency.

As is clear from Tables 4 to 6, when BaMgAl ₁₀ O ₁₇ : Eu ²⁺ was used as the phosphor powder and the measurement was performed on a light source of 405 nm, No. The wavelength conversion members 1 to 13 had a luminous efficiency of 5.5 lm / W or more, whereas No. 1 was a comparative example. The wavelength conversion member of No. 14 had a low luminous efficiency of 2.9 lm / W.

Further, when α-SiAlON was used as the phosphor powder and the measurement was performed on a light source of 460 nm, No. The wavelength conversion members 1 to 13 had a luminous efficiency of 7.2 lm / W or more, whereas No. 1 was a comparative example. The wavelength conversion member of No. 14 had a low luminous efficiency of 4.2 lm / W.

In addition, No. Since the wavelength conversion members 1 to 13 are manufactured by using a glass powder sample having excellent weather resistance, the surface is not easily deteriorated even after being used for a long period of time, and the luminous efficiency is significantly reduced. It is thought that it is unlikely to occur.

The glass of the present invention is suitable as a wavelength conversion member glass used for general lighting such as a single color or white LED, special lighting (for example, a projector light source, an in-vehicle head lamp light source), and the like.

1 Light emitting device 2 Wavelength conversion member 3 Light source

Claims (11)

Glass used as a wavelength conversion material, in terms of mass%, SiO ₂ 55 to 75%, B ₂ O ₃ 1 to 30%, Al ₂ O ₃ 5.5 to 20%, Li ₂ O 0.1 to 10 %, Na ₂ O + K ₂ O 0 to 8%, MgO + CaO + SrO + BaO + ZnO 0 to 10%. The glass according to claim 1, wherein the glass does not substantially contain a lead component and an arsenic component. The glass according to claim 1 or ₂ , further comprising ZrO 20 to 10% by mass. The glass according to any one of claims 1 to 3, wherein the softening point is 750 ° C. or lower. The glass according to any one of claims 1 to 4, wherein the degree of coloring λ ₈₀ is 400 nm or less. The glass according to any one of claims 1 to 5, wherein the glass is in the form of powder. A wavelength conversion material comprising the glass according to claim 6 and a phosphor. The phosphor is one or more selected from a nitride phosphor, an oxynitride phosphor, an oxide phosphor, a sulfide phosphor, an acid sulfide phosphor, a halide phosphor, and an aluminate phosphor. The wavelength conversion material according to claim 7. A wavelength conversion member comprising a sintered body of the wavelength conversion material according to claim 7 or 8. It is a wavelength conversion member in which a fluorescent substance is dispersed in a glass matrix, and the glass matrix has a mass% of SiO ₂ 55 to 75%, B ₂ O ₃ 1 to 30%, and Al ₂ O ₃ 5.5 to. A wavelength conversion member comprising 20%, Li ₂ O 0.1 to 10%, Na ₂ O + K ₂ O 0 to 8%, MgO + CaO + SrO + BaO + ZnO 0 to 10%. The light emitting device according to claim 9 or 10, further comprising a wavelength conversion member and a light source for irradiating the wavelength conversion member with excitation light.

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