JP2017083814A - Wavelength conversion member and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion member capable of minimizing discoloration thereof when irradiated with excitation light and temporal degradation of inorganic nanophosphor particles.SOLUTION: A wavelength conversion member 10 comprises a first substrate 1, a second substrate 2, and a phosphor layer 3 which is formed between the first substrate 1 and the second substrate 2 and contains inorganic nanophosphor particles. The first substrate 1 and the second substrate 2 are made of an inorganic material, and peripheral edge portions thereof are fused together.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wavelength conversion member using inorganic nanocrystalline phosphor particles and a method for producing the same.

  In recent years, a light-emitting device using an excitation light source such as a light emitting diode (LED) or a semiconductor laser (LD) and using fluorescence generated by irradiating the phosphor with excitation light generated from these excitation light sources has been studied. Has been. In addition, the use of inorganic nanophosphor particles such as quantum dots as a phosphor has been studied. The quantum dot can be adjusted in fluorescence wavelength by changing its diameter, and has high luminous efficiency (see, for example, Patent Documents 1 to 3).

  Inorganic nanophosphor particles have the property of being easily deteriorated when they come into contact with moisture or oxygen in the atmosphere. For this reason, the inorganic nanophosphor particles are used by being sealed with a resin or the like so as not to contact the external environment.

International Publication No. 2012/102107 International Publication No. 2012/161065 Special table 2013-525243 gazette

  When a resin is used as the sealing material, there is a problem that the resin is discolored by heat generated from the inorganic nanophosphor particles when irradiated with excitation light. Further, since the resin is inferior in water resistance and easily penetrates moisture, there is a problem that the inorganic nanophosphor particles are likely to deteriorate over time.

  In view of the above, an object of the present invention is to provide a wavelength conversion member capable of suppressing discoloration of a member when irradiated with excitation light and deterioration with time of inorganic nanophosphor particles.

  The wavelength conversion member of the present invention has a first substrate and a second substrate, and a phosphor layer containing inorganic nanophosphor particles formed between the first substrate and the second substrate. The wavelength conversion member is characterized in that the first substrate and the second substrate are made of an inorganic material and are fused to each other.

  Since the wavelength conversion member of the present invention has the above configuration, the inorganic nanophosphor particles are sealed between the first substrate and the second substrate made of an inorganic material. Therefore, the inorganic nanophosphor particles are hardly affected by the external environment, and can be prevented from deterioration over time. Moreover, unlike the case of resin sealing, by using an inorganic material as a substrate for sealing inorganic nanophosphor particles, discoloration of a member when irradiated with excitation light can be suppressed.

  In the wavelength conversion member of the present invention, it is preferable that the first substrate and the second substrate are fused to each other at the peripheral portion.

  In the wavelength conversion member of the present invention, it is preferable that the yield point of at least one of the first substrate and the second substrate is 380 ° C. or lower. According to the said structure, degradation of an inorganic nano fluorescent substance particle can be suppressed at the heat processing process at the time of producing a wavelength conversion member.

  In the wavelength conversion member of the present invention, it is preferable that at least one of the first substrate and the second substrate is made of glass. Glass is difficult to permeate moisture and oxygen due to its structure, and thus has a high effect of suppressing deterioration of inorganic nanophosphor particles. Moreover, since it is excellent also in heat resistance compared with resin, the discoloration of the member at the time of irradiating excitation light can be suppressed. Furthermore, since glass is excellent in light transmittance, the incident efficiency of excitation light and the emission efficiency of fluorescence can be increased, and as a result, the light emission efficiency of the wavelength conversion member can be increased.

  In the wavelength conversion member of the present invention, the glass is preferably Sn-P glass or Sn-PF glass. Sn-P glass and Sn-PF glass are preferable because the yield point can be easily lowered.

In the wavelength conversion member of the present invention, Sn-P-based glass is mol%, SnO 50-80%, P ₂ O ₅ 15-25% (however, 25% is not included), ZrO ₂ 0-3%, _{al 2 O 3 0~10%, B} 2 O 3 0~10%, 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 ~10%, 0~10% MgO, CaO 0~3%, SrO 0~2.5%, BaO 0~2%, MgO + CaO + SrO + BaO 0~11% and _{ZrO 2 +} Al 2 O 3 ₊ containing 0% MgO SnO / P ₂ O ₅ is preferably 1.6 to 4.8.

In the wavelength converting member of the present invention, Sn-P-F-based glass, by ^{cationic%, Sn 2+ 10~90%, P} 5+ 10~70%, by ^anionic%, O 2- ^30~99.9%, F ^- preferably contains 0.1 to 70%.

  In the wavelength conversion member of the present invention, the inorganic nanophosphor particles are selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, InP, GaN, GaAs, GaP, AlN, AlP, AlSb, InN, InAs, and InSb. A quantum dot phosphor composed of at least one kind or a composite of two or more of these is preferred. Alternatively, the inorganic nanophosphor particles are inorganic particles composed of at least one selected from oxides, nitrides, oxynitrides, sulfides, oxysulfides, rare earth sulfides, aluminate chlorides, and halophosphates. It may be.

  In the wavelength conversion member of the present invention, the phosphor layer is preferably formed by dispersing inorganic nanophosphor particles in a glass matrix. According to this configuration, the inorganic nanophosphor particles are less susceptible to the influence of the external environment, which is advantageous for suppressing deterioration over time.

  In the wavelength conversion member of the present invention, a reflective film may be formed on the surface of the first substrate on the phosphor layer side. If it does in this way, it will become possible to use as a reflection type wavelength conversion member.

  In the wavelength conversion member of the present invention, a bandpass filter may be formed on the surface of the first substrate on the phosphor layer side. In this way, it is possible to increase the efficiency of extracting light having a required wavelength (for example, fluorescence) to the outside.

  In the wavelength conversion member of the present invention, it is preferable that the bandpass filter transmits the excitation light and reflects the fluorescence emitted from the phosphor layer.

  In the wavelength conversion member of the present invention, it is preferable that an antireflection film is formed on the surface of the second substrate opposite to the phosphor layer. In this way, it is possible to increase the efficiency of taking out fluorescence (or excitation light) to the outside.

  In the method for producing a wavelength conversion member of the present invention, a phosphor layer containing inorganic nanophosphor particles is sandwiched between a first substrate and a second substrate, and thermocompression-pressed using a mold. The first substrate and the second substrate are fused to each other.

  By performing thermocompression pressing using a mold, the first substrate and the second substrate can be fused to each other in a relatively short time, so that thermal degradation of the inorganic nanophosphor particles in the manufacturing process is suppressed. be able to. Further, even when the first substrate and the second substrate are made of a brittle material such as glass (particularly Sn—P—F-based glass), the manufacturing method of the present invention has an advantage that the member is not easily damaged. . Therefore, a thin wavelength conversion member can be easily produced. Note that when the phosphor layer is formed by the paste method or the green sheet method, the carbon component due to the solvent, the binder, or the like may remain in the sintered body, which may cause a decrease in emission intensity. On the other hand, according to the production method of the present invention, it is not necessary to use an organic compound such as a solvent or a binder, and thus it is possible to prevent a decrease in emission intensity due to the carbon component.

  In the manufacturing method of the wavelength conversion member of this invention, it is preferable to perform a thermocompression-bonding press at 400 degrees C or less. If it does in this way, the thermal deterioration of the inorganic nano fluorescent substance particle at the time of thermocompression-bonding press can be suppressed. Note that general inorganic nanophosphor particles (especially quantum dot phosphors) are deteriorated by heat exceeding 350 ° C. and light emission efficiency is reduced, but the substrates are fused in a relatively short time by a thermocompression press. Therefore, a decrease in the luminous efficiency of the inorganic nanophosphor particles can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the wavelength conversion member which can suppress the discoloration of the member at the time of irradiating excitation light, and temporal deterioration of an inorganic nano fluorescent substance particle.

(A) It is a typical sectional view of a wavelength conversion member concerning a 1st embodiment of the present invention. (B) It is a typical top view of the wavelength conversion member concerning a 1st embodiment. It is typical sectional drawing which shows the manufacturing process of the wavelength conversion member which concerns on the 1st Embodiment of this invention. It is a typical sectional view of a wavelength conversion member concerning a 2nd embodiment of the present invention. It is a typical sectional view of a wavelength conversion member concerning a 3rd embodiment of the present invention. It is a plane photograph at the time of irradiating the wavelength conversion member obtained in Example 4 with excitation light.

  Hereinafter, embodiments of the wavelength conversion member of the present invention will be described with reference to the drawings.

(1) 1st Embodiment (a) of FIG. 1 is typical sectional drawing of the wavelength conversion member 10 which concerns on the 1st Embodiment of this invention, (b) is typical plan view of the wavelength conversion member 10 It is.

  The wavelength conversion member 10 includes a first substrate 1 and a second substrate 2 made of an inorganic material, and a phosphor layer 3 formed therebetween. The phosphor layer 3 contains inorganic nanophosphor particles. The phosphor layer 3 is formed only on the substantially central portion of the first substrate 1 and the second substrate 2. That is, the phosphor layer 3 is not formed on the peripheral portions of the first substrate 1 and the second substrate 2. Here, a recess may be formed on at least one surface of the first substrate and the second substrate, and the phosphor layer 3 may be formed in the recess. In this case, the boundary between the region where the phosphor layer 3 is formed and the region where the phosphor layer 3 is not formed tends to be clear. For example, the phosphor layer 3 can be efficiently irradiated with the light emitted from the light source by matching the shape of the concave portion with the shape of the light emitting surface of the light source (for example, LED chip). The 1st board | substrate 1 and the 2nd board | substrate 2 are mutually fuse | fused over the perimeter by the peripheral parts 1a and 2a. Thereby, since the phosphor layer 3 is completely sealed by the first substrate 1 and the second substrate 2, it is not easily affected by the external environment. Therefore, deterioration with time of the inorganic nanophosphor particles can be suppressed.

The 1st board | substrate 1 and the 2nd board | substrate 2 consist of translucent materials, such as glass, for example. By constituting both the first substrate 1 and the second substrate 2 with a translucent material, it can be used as a transmissive wavelength conversion member. For example, when the excitation light L ₀ is irradiated from the first substrate 1 side, the fluorescence L ₁ is emitted from the phosphor layer 3 and is extracted from the second substrate 2 side to the outside. At this time, the combined light of the fluorescence emitted from the phosphor layer 3 and the excitation light that has not been wavelength-converted may be extracted from the second substrate 2 side to the outside. Here, an antireflection film (not shown) may be formed on the surface of the second substrate 2 opposite to the phosphor layer 3. In this way, the extraction efficiency of excitation light and fluorescence can be improved.

  The glass is preferably a glass based on Sn and P, such as Sn-P glass, Sn-PB glass, Sn-PF glass, etc. having a low yield point. Among these, Sn—PF glass is preferable because it is easy to lower the yield point.

The Sn-P-F-based glass, ^{cationic%, Sn 2+ 10~90%, P} 5+ 10~70%, by ^{anionic%, O 2- 30~99.9%, F} - 0.1~70% The thing containing is mentioned. The reason why the content of each component is limited in this way will be described below. Unless otherwise specified, in the following description regarding the content of each component, “%” means “cation%” or “anion%”.

Sn ²⁺ is a component that improves chemical durability and weather resistance. It also has the effect of lowering the yield point. The Sn ²⁺ content is preferably 10 to 90%, 20 to 85%, particularly preferably 25 to 82.5%. When the content of Sn ²⁺ is too small, the above effect is difficult to obtain. On the other hand, when there is too much content of Sn2 ⁺ , it will become difficult to vitrify or devitrification resistance will fall easily.

P ⁵⁺ is a constituent component of the glass skeleton. Moreover, it has the effect of increasing the light transmittance. It also has the effect of suppressing devitrification and lowering the yield point. The content of P ⁵⁺ is preferably 10 to 70%, 15 to 60%, and particularly preferably 20 to 50%. When there is too little content of ^{P5 +} , the said effect will become difficult to be acquired. On the other hand, when the content of P ⁵⁺ is too large, the content of Sn ²⁺ is relatively low, the weather resistance tends to lower.

The content of P ⁵⁺ and Sn ²⁺ is preferably 50% or more, 70.5% or more, 75% or more, 80% or more, and particularly preferably 85% or more. When the content of P ⁵⁺ and Sn ²⁺ is too small, devitrification resistance and mechanical strength tends to decrease. The upper limit of the content of P ⁵⁺ and Sn ²⁺ is not particularly limited and may be 100%. However, when other components are contained, they are 99.9% or less, 99% or less, 95% or less, and further 90%. % Or less.

  In addition to the above components, the following components can be contained as the cationic component.

B ³⁺ , Zn ²⁺ , Si ⁴⁺ and Al ³⁺ are components of the glass skeleton, and have a particularly large effect of improving chemical durability. The content of B ³⁺ + Zn ²⁺ + Si ⁴⁺ + Al ³⁺ is preferably 0 to 50%, 0 to 30%, 0.1 to 25%, 0.5 to 20%, particularly preferably 0.75 to 15%. When the content of ^{B 3+ + Zn 2+ + Si 4+} + Al 3+ is too large, the devitrification resistance tends to decrease. Moreover, Sn metal etc. precipitate with a raise of melting temperature, and light transmittance becomes easy to fall. Also, the yield point tends to rise. From the viewpoint of improving the weather resistance, it is preferable to contain 0.1% or more of B ³⁺ + Zn ²⁺ + Si ⁴⁺ + Al ³⁺ .

The preferable content range of each component of B ³⁺ , Zn ²⁺ , Si ⁴⁺ and Al ³⁺ is as follows.

B ³⁺ is a component constituting the glass skeleton. Moreover, there exists an effect which improves a weather resistance, and especially the effect which suppresses that components, such as ^{P5 +} in glass, elute selectively into water is large. The content of B ³⁺ is preferably 0 to 50%, 0.1 to 45%, particularly preferably 0.5 to 40%. When there is too much content of ^{B3 +} , there exists a tendency for devitrification resistance and a light transmittance to fall.

Zn ²⁺ is a component that acts as a flux. Moreover, there exists an effect which improves a weather resistance, suppresses the elution of the glass component in various washing | cleaning solutions, such as polishing washing water, and suppresses the quality change of the glass surface in a hot and humid state. Zn ²⁺ also has the effect of stabilizing vitrification. In view of the above, the content of Zn ²⁺ is preferably 0 to 40%, 0.1 to 30%, particularly preferably 0.2 to 20%. When there is too much content of Zn2 ⁺ , there exists a tendency for devitrification resistance and a light transmittance to fall.

Si ⁴⁺ is a component constituting a glass skeleton. Moreover, there exists an effect which improves a weather resistance, and especially the effect which suppresses that components, such as ^{P5 +} in glass, elute selectively into water is large. The content of Si ⁴⁺ is preferably 0 to 20%, particularly preferably 0.1 to 15%. When the content of Si ⁴⁺ is too large, the yield point tends to be high. In addition, striae and bubbles due to undissolved are likely to remain in the glass.

Al ³⁺ is a component capable of constituting a glass skeleton together with Si ⁴⁺ and B ³⁺ . Moreover, there exists an effect which improves a weather resistance, and especially the effect which suppresses that components, such as ^{P5 +} in glass, elute selectively into water is large. The content of Al ³⁺ is preferably 0 to 20%, particularly preferably 0.1 to 15%. When there is too much content of ^{Al3 +} , there exists a tendency for devitrification resistance and a light transmittance to fall. Further, the melting temperature is increased, and striae and bubbles due to undissolution are likely to remain in the glass.

Mg ²⁺ , Ca ²⁺ , Sr ²⁺ and Ba ²⁺ (alkaline earth metal ions) are components that act as fluxes. Moreover, there exists an effect which improves a weather resistance, suppresses the elution of the glass component in various washing | cleaning solutions, such as polishing washing water, and suppresses the quality change of the glass surface in a hot and humid state. Moreover, it is a component which raises the hardness of glass. However, when there is too much content of these components, devitrification resistance will fall easily. Therefore, the content of Mg ²⁺ , Ca ²⁺ , Sr ²⁺ and Ba ²⁺ is preferably 0 to 10%, 0 to 7.5%, 0.1 to 5%, particularly preferably 0.2 to 1.5%.

Li ⁺ is a component having the greatest effect of lowering the yield point among alkali metal oxides. However, since Li ⁺ has a strong phase separation property, if its content is too large, the devitrification resistance tends to decrease. In addition, Li ⁺ tends to reduce chemical durability and light transmittance. Therefore, the content of Li ⁺ is preferably 0 to 10%, 0 to 5%, 0 to 1%, particularly preferably 0 to 0.1%.

Na ⁺ has the effect of lowering the yield point in the same manner as Li ⁺ . However, when the content is too large, striae are easily generated. Further, the devitrification resistance is likely to be lowered. Further, Na ⁺ tends to reduce chemical durability and light transmittance. Therefore, the Na ⁺ content is preferably 0 to 10%, 0 to 5%, 0 to 1%, particularly preferably 0 to 0.1%.

K ⁺ also has the effect of lowering the yield point in the same way as Li ⁺ . However, if the content is too large, the weather resistance tends to decrease. Further, the devitrification resistance is likely to be lowered. Further, K ⁺ tends to reduce chemical durability and light transmittance. Therefore, the content of K ₂ O is preferably 0 to 10%, 0 to 5%, 0 to 1%, particularly preferably 0 to 0.1%.

In addition, it is preferable that the content of Li ^<+> , Na ^<+> and K ^<+> is 0 to 10%, 0 to 5%, 0 to 1%, particularly 0 to 0.1%. When there is too much content of Li ^<+> , Na ^<+> and K ^{< + >} , it will become easy to devitrify and there exists a tendency for chemical durability to fall.

In addition to the above components, La ³⁺ , Gd ³⁺ , Ta ⁵⁺ , W ⁶⁺ , Nb ⁵⁺ , Ti ⁴⁺ , Y ³⁺ , Yb ³⁺ , Ge ⁴⁺ , Te ⁴⁺ , Bi ³⁺ and Zr ⁴⁺ are contained up to 10%. Can be made.

Rare earth components such as Ce ⁴⁺ , Pr ³⁺ , Nd ³⁺ , Eu ³⁺ , Tb ³⁺ and Er ³⁺ , Fe ³⁺ , Ni ²⁺ and Co ²⁺ are components that reduce the light transmittance. Therefore, the content of these components is preferably 0.1% or less, and more preferably not contained.

Since In ³⁺ has a strong devitrification tendency, it is preferably not contained.

Incidentally, for environmental reasons, it is preferred not to contain ^{Pb 2+} and ^{As 3+.}

F ⁻ which is an anionic component has an effect of lowering the yield point and an effect of increasing the light transmittance. However, if the content is too large, the volatility at the time of melting becomes high and striae easily occurs. Further, the devitrification resistance is likely to be lowered. The content of F ⁻ is preferably 0.1 to 70%, 1 to 67.5%, 5 to 65%, 2 to 60%, particularly 10 to 60%. In addition, examples of the raw material for introducing F ⁻ include fluorides such as La, Gd, Ta, W, Nb, Y, Yb, Ge, Mg, Ca, Sr, and Ba, in addition to SnF ₂ .

In addition, as anion components other than F ⁻ , O ^{2 −} is usually contained. That is, the content of O ²⁻ is determined according to the content of F ⁻ . Specifically, the content of O ²⁻ is preferably 30 to 99.9%, 32.5 to 99%, 35 to 95%, 40 to 98%, particularly 40 to 90%.

The sn-P based glass, in _{mol%, SnO 50~80%, P 2} O 5 15~25% ( however, not including _{25%), ZrO 2 0~3%} , Al 2 O 3 0~10 _{%, B 2 O 3 0~10%} , Li 2 O 0~10%, Na 2 O 0~10%, K 2 O 0~10%, Li 2 O + Na 2 O + K 2 O 0~10%, MgO 0~ 10%, CaO 0-3%, SrO 0-2.5%, BaO 0-2%, MgO + CaO + SrO + BaO 0-11% and ZrO ₂ + Al ₂ O ₃ + MgO 0-10%, SnO / P ₂ O ₅ What is 1.6-4.8 is mentioned.

  The yield points of the first substrate 1 and the second substrate 2 are preferably 380 ° C. or lower, 300 ° C. or lower, particularly 200 ° C. or lower. If the yield point of the first substrate 1 and the second substrate 2 is too high, the inorganic nanophosphor particles are likely to deteriorate in the heat treatment step when the wavelength conversion member 10 is produced. On the other hand, the lower limit of the yield point of the first substrate 1 and the second substrate 2 is not particularly limited, but is actually 100 ° C. or higher, particularly 120 ° C. or higher. Here, the yield point refers to the point at which the test piece showed the maximum elongation in the measurement with the thermal expansion coefficient measurement (TMA) apparatus, that is, the value at which the elongation of the test piece stopped.

In addition, although the yield point of both the 1st board | substrate 1 and the 2nd board | substrate 2 may be in the said range, only one of the yield points may be in the said range. For example, when the yield point of the first substrate 1 is in the above range and the yield point of the second substrate 2 is higher than the above range, the heat treatment is performed at the yield point to the yield point + 100 ° C. of the first substrate 1. As a result, the first substrate 1 can be softened and deformed and fused to the second substrate 2. For example, the first substrate 1 is made of a low yield point glass such as Sn—PF glass, and the second substrate 2 has a relatively high yield point such as silicate glass, borosilicate glass, or quartz glass. It may be made of glass, or may be made of ceramics such as Al ₂ O ₃ and AlN. Alternatively, the first substrate 1 is made of a low yield point glass such as Sn—PF glass, and the second substrate 2 is made of a metal such as Al, Cu, Ag, etc. It is good also as a member. From the viewpoint of matching the thermal expansion coefficients of the first substrate 1 and the second substrate 2, the difference in thermal expansion coefficient between them (temperature range: 30 to 380 ° C.) is ± 50 × 10 ⁻⁷ / ° C., particularly ± 30 ×. It is preferably within the range of 10 ⁻⁷ / ° C.

  The thickness of the first substrate 1 and the second substrate 2 is preferably 0.1 to 1 mm, particularly preferably 0.1 to 0.5 mm. If the thickness of the first substrate 1 and the second substrate 2 is too small, the mechanical strength is lowered, and therefore, the first substrate 1 and the second substrate 2 are easily damaged during manufacturing and use. On the other hand, when the thickness of the 1st board | substrate 1 and the 2nd board | substrate 2 is too large, the time required in order to fuse both with a thermocompression press will become long, and inorganic nano fluorescent substance particle will deteriorate easily.

  Inorganic nanophosphor particles used for the phosphor layer 3 include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, etc. as II-VI group compounds, InP, GaN, GaAs, GaP, AlN as III-V compounds. Examples thereof include quantum dot phosphors such as AlP, AlSb, InN, InAs, and InSb. These can be used alone or in admixture of two or more. Or you may use the composite_body | complex (For example, the core shell structure by which the surface of CdSe particle | grains was coat | covered with ZnS) which consists of these 2 or more types. In addition to quantum dot phosphors, inorganic nanophosphor particles include oxides, nitrides, oxynitrides, sulfides, oxysulfides, rare earth sulfides, aluminate chlorides, halophosphates, and the like. What consists of inorganic particles can also be used. These can be used alone or in admixture of two or more. The average particle size of the inorganic nanophosphor particles is not particularly limited, but is usually 100 nm or less, 50 nm or less, particularly 1 to 30 nm, 1 to 15 nm, or even about 1.5 to 12 nm. In addition, in this specification, an average particle diameter points out the value (D50) measured based on JIS-R1629.

  The phosphor layer 3 may be formed by dispersing inorganic nanophosphor particles in a glass matrix. In this way, since the sealing properties of the inorganic nanophosphor particles are improved, deterioration over time can be easily suppressed. The phosphor layer 3 may contain a light diffusing material such as alumina or silica.

  Next, the manufacturing method of the wavelength conversion member 10 is demonstrated based on FIG.

  First, a laminate is prepared in which a phosphor layer 3 containing inorganic nanophosphor particles 3 is sandwiched between a first substrate 1 and a second substrate 2. The phosphor layer 3 is formed only on the substantially central portion of the first substrate 1 and the second substrate 2, and the phosphor layer is formed on the peripheral portion 1 a of the first substrate 1 and the peripheral portion 2 a of the second substrate 2. 3 is not formed. Next, the laminate is placed between the upper mold 4 a and the lower mold 4 b in the mold 4. After preheating as necessary, pressure P is applied to the upper mold 4a to perform thermocompression pressing. As a result, the peripheral edge 1a of the first substrate 1 and the peripheral edge 2a of the second substrate 2 are softened and fused together, and the phosphor layer 3 containing inorganic nanophosphor particles is sealed between the two substrates. Is done. In this way, the wavelength conversion member 10 is obtained.

  In addition, the area | region of the fluorescent substance layer 3 has the tendency for the area to expand after a thermocompression press compared with the thermocompression press. Therefore, the thermocompression pressing may be performed in a state where a recess is formed on at least one surface of at least the first substrate and the second substrate and the phosphor layer 3 is formed in the recess. In this case, the phosphor layer 3 tends to stay in the recess even after the thermocompression pressing, and the boundary between the region where the phosphor layer 3 is formed and the region where the phosphor layer 3 is not formed is clear as described above. It is easy to become.

  In addition, thermocompression bonding is performed using a mold in a state where a phosphor layer 3 made of a mixture of inorganic nanophosphor particles and glass powder as a dispersion medium is sandwiched between the first substrate 1 and the second substrate 2. You may press. In this way, it is possible to produce a wavelength conversion member in which the phosphor layer 3 in which inorganic nanophosphor particles are dispersed in a glass matrix is sealed between both substrates. As a glass powder, it is preferable to use what consists of Sn-FP glass which has a low yield point. In this way, since the glass powder softens and flows during the thermocompression pressing and becomes a dense structure, the sealing performance of the inorganic nanophosphor particles can be improved. In addition, the thickness of the phosphor layer 3 can be easily increased, and the amount of inorganic nanophosphor particles contained in the phosphor layer 3 can be increased. As a result, the emission intensity of the wavelength conversion member 10 can be easily increased.

  As a dispersion medium, in addition to glass powder, silicone resin, epoxy resin, urethane resin, acrylic resin, polycarbonate resin, etc .; alumina powder, silica powder, titania powder, zinc oxide powder, calcium carbonate powder, barium sulfate powder, etc. Inorganic powders such as: cellulose fibers, chitin fibers, chitosan fibers, inorganic fibers other than carbon, and organic polymer fibers. In addition, you may form the fluorescent substance layer 3 by carrying | supporting inorganic nano fluorescent substance particles on sheet-like media, such as an alumina sheet and a cellulose fiber sheet. For example, the inorganic nanophosphor particles can be supported on the sheet-like medium by immersing the dispersion liquid in which the inorganic nanophosphor particles are dispersed in a dispersion medium such as hexane into the sheet-like medium and then drying. .

  The temperature of the thermocompression-bonding press is preferably not less than the yield point of the substrate having the lower yield point of the first substrate 1 or the second substrate 2, particularly not less than the yield point + 20 ° C. If the thermocompression press temperature is too low, it is difficult to fuse both substrates. On the other hand, the upper limit of the temperature of the thermocompression press is preferably the yield point + 100 ° C. or less of the substrate having the lower yield point of the first substrate 1 or the second substrate 2, particularly the yield point + 50 ° C. or less. . If the thermocompression pressing temperature is too high, the inorganic nanophosphor particles are likely to deteriorate. Specifically, the temperature of the thermocompression pressing is about 130 to 400 ° C, and further about 150 to 300 ° C. For example, when the first substrate 1 or the second substrate 2 is Sn—P—F-based glass, the temperature of the thermocompression press is preferably 130 to 350 ° C., particularly preferably 130 to 250 ° C.

The pressure of the thermocompression press is preferably 10 to 400 kPa / cm ² , particularly preferably ²⁰ to 300 kPa / cm ² . When the pressure of the thermocompression press is too low, the first substrate 1 and the second substrate 2 are difficult to fuse. On the other hand, when the pressure of the thermocompression press is too high, the first substrate 1 and the second substrate 2 are easily damaged. In addition, when the 1st board | substrate 1 or the 2nd board | substrate 2 is Sn-PF system glass, in order to suppress the failure | damage at the time of a press, it is 10-30 kPa / cm < ² >, Especially 15-25 kPa / cm < ² >. Preferably there is.

  The thermocompression press time is preferably 0.1 to 10 minutes, 0.3 to 5 minutes, 0.4 to 3 minutes, particularly preferably 0.5 to 2 minutes. When the time of the thermocompression pressing is too short, the first substrate 1 and the second substrate 2 are difficult to fuse. On the other hand, if the time of the thermocompression pressing is too long, the inorganic nanophosphor particles are likely to be deteriorated.

  The atmosphere of the thermocompression press may be an air atmosphere, but in order to suppress problems such as deactivation of inorganic nanophosphor particles and deterioration due to oxidation of the mold, a reduced pressure atmosphere or an inert atmosphere, especially running cost is considered. A nitrogen atmosphere is preferred. In addition, when using Sn-PF glass as the first substrate 1 or the second substrate 2, the atmosphere of the thermocompression press can be reduced by setting the atmosphere of the thermocompression press to a reduced pressure atmosphere or an inert atmosphere. Denaturation can be suppressed.

(2) Second Embodiment FIG. 3 is a schematic cross-sectional view of a wavelength conversion member 20 according to a second embodiment of the present invention. The wavelength conversion member 20 is different from the wavelength conversion member 10 according to the first embodiment in that the reflective film 5 is formed on the surface of the first substrate 1 on the phosphor layer 3 side.

The wavelength conversion member 20 can be used as a reflective wavelength conversion member. Specifically, when the excitation light L ₀ is irradiated from the second substrate 2 side, the fluorescence L ₁ generated by the wavelength conversion of the excitation light in the phosphor layer 3 (or excitation light that has not been wavelength-converted) is The reflection film 5 reflects the excitation light incident side and takes it out.

  Examples of the reflective film 5 include metal thin films such as Ag and Al. Examples of the method for forming the metal thin film include a plating method, a vacuum deposition method, an ion plating method, and a sputtering method.

(3) Third Embodiment FIG. 4 is a schematic cross-sectional view of a wavelength conversion member 30 according to a third embodiment of the present invention. The wavelength conversion member 30 is different from the wavelength conversion member 10 according to the first embodiment in that a band pass filter 6 is formed on the surface of the first substrate 1 on the phosphor layer 3 side.

As the band-pass filter 6, for example, a filter that transmits excitation light and reflects fluorescence emitted from the phosphor layer 3 can be used. In this way, when the excitation light L ₀ is irradiated from the first substrate 1 side, the excitation light passes through the band-pass filter 6 to excite the inorganic nanophosphor particles in the phosphor layer 3 and the phosphor. The fluorescence L ₁ emitted from the layer 3 is reflected by the bandpass filter 6 toward the second substrate 2 side. As a result, it is possible to efficiently extract the fluorescence to the second substrate 2 side.

Specific examples of the bandpass filter 6 include a high refractive index film made of Nb ₂ O ₅ , TiO ₂ , Ta ₂ O ₅ , HfO ₂ , ZrO ₂ , Al ₂ O ₃ , SiN, etc., SiO ₂ , MgF _2, etc. And a dielectric multilayer film in which low refractive index films made of fluoride or the like are alternately laminated.

  The wavelength conversion members 10 to 30 described above can be used as a light emitting device by combining with an excitation light source such as an LED or an LD.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these Examples.

Example 1
_SnO, a SnF _2, P _{2 O 5} as starting materials, by ^{cationic%, Sn 2+ 56.3%, P} 5+ 43.8%, by ^{anionic%, F - 24.8%, O} 2- 75.2% The batch prepared so as to contain the solution was put into a quartz beaker and melted at 680 ° C. for 5 minutes in an electric furnace in a nitrogen atmosphere. The obtained molten glass was formed into an ingot shape and cut and subjected to double-side polishing to produce two glass plates having a size of 15 mm × 15 mm × 1 mm (deflection point = 150 ° C.).

100 μl of a dispersion liquid in which inorganic nanophosphor particles (CdSe / ZnS, average particle diameter = about 3 nm) are dispersed in hexane as a dispersion medium at a concentration of 1% by mass is applied to the substantially central portion of the surface of one glass plate. Then, vacuum drying was performed to form a phosphor layer made of inorganic nanophosphor particles. The laminate obtained by stacking the other glass plate on the phosphor layer was sandwiched between tungsten carbide press dies and preheated at 180 ° C. for 2 minutes in a nitrogen atmosphere. Then, thermocompression pressing was performed for 20 seconds at a pressure of 14 kPa / cm ^{2 while} maintaining the temperature at 180 ° C. As a result, the peripheral portions of the two glass plates were fused together, and a wavelength conversion member was obtained.

  With respect to the obtained wavelength conversion member, the light emission quantum efficiency (internal quantum efficiency) was measured to be 43%. In addition, the light emission quantum efficiency points out the value calculated by the following formula, and measured using the absolute PL quantum yield apparatus made from Hamamatsu Photonics. A quartz plate was used as a reference.

    Luminescence quantum efficiency = {(number of photons emitted from the sample as luminescence) / (number of photons absorbed from the sample)} × 100 (%)

(Example 2)
The ingot-shaped glass produced in Example 1 was pulverized in a mortar to obtain glass powder (average particle size = 25 μm). 100 μl of the inorganic nanophosphor particle dispersion prepared in Example 1 was added to and mixed with 0.2 g of the glass powder, followed by vacuum drying to obtain a mixture of glass powder and inorganic nanophosphor particles. The laminate obtained by sandwiching the obtained mixture between the two glass plates obtained in Example 1 was sandwiched between the lower molds of a tungsten carbide press mold, and at 180 ° C. for 2 minutes in a nitrogen atmosphere. Preheated. Then, thermocompression pressing was performed for 20 seconds at a pressure of 14 kPa / cm ^{2 while} maintaining the temperature at 180 ° C. As a result, the peripheral portions of the two glass plates were fused together, and a wavelength conversion member was obtained. With respect to the obtained wavelength conversion member, the light emission quantum efficiency was measured and found to be 40%.

(Example 3)
A wavelength conversion member was produced in the same manner as in Example 1 except that the temperature of the preheating and thermocompression pressing was 200 ° C. The obtained wavelength conversion member was measured for luminescence quantum efficiency and found to be 30%.

Example 4
Two glass plates having a size of 10 mm × 7 mm × 1 mm were produced in the same manner as in Example 1. With an aluminum foil of 2 mm × 6 mm × 1.1 mm placed at the center of one glass plate surface, this was sandwiched between tungsten carbide press dies and preheated at 180 ° C. for 2 minutes in a nitrogen atmosphere. Then, thermocompression pressing was performed for 20 seconds at a pressure of 14 kPa / cm ^{2 while} maintaining the temperature at 180 ° C. Thereby, a rectangular recess having a depth of about 0.13 mm was formed on the glass plate surface. 100 μl of the inorganic nanophosphor particle dispersion prepared in Example 1 was applied to the recesses on the surface of the glass plate and vacuum dried to form a phosphor layer composed of inorganic nanophosphor particles. The upper and lower sides of the laminate obtained by stacking the other glass plate on the phosphor layer were sandwiched between tungsten carbide press dies and preheated at 180 ° C. for 2 minutes in a nitrogen atmosphere. Then, thermocompression pressing was performed for 20 seconds at a pressure of 14 kPa / cm ^{2 while} maintaining the temperature at 180 ° C. As a result, the peripheral portions of the two glass plates were fused together, and a wavelength conversion member was obtained. FIG. 5 shows a plan photograph when the obtained wavelength conversion member is irradiated with excitation light (wavelength 365 nm). With respect to the obtained wavelength conversion member, the light emission quantum efficiency was measured and found to be 48%.

(Example 5)
A mixture of 100 μl of the inorganic nanophosphor particle dispersion prepared in Example 1 and 1 g of a silicone resin (LPS5500 (A / B) manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the recesses on the surface of the glass plate, dried at room temperature, and inorganic nano A wavelength conversion member was produced in the same manner as in Example 4 except that a phosphor layer made of phosphor particles was formed. With respect to the obtained wavelength conversion member, the light emission quantum efficiency was measured and found to be 55%.

(Example 6)
A mixture of 100 μl of the inorganic nanophosphor particle dispersion prepared in Example 1 and 0.19 g of a surface hydrophobized alumina powder (average particle size 13 nm) was applied to the recesses on the surface of the glass plate and dried in vacuo to form inorganic nanophosphor particles. A wavelength conversion member was produced in the same manner as in Example 4 except that the phosphor layer made of was formed. With respect to the obtained wavelength conversion member, the light emission quantum efficiency was measured and found to be 44%.

(Example 7)
A mixture of 1.6 ml of the inorganic nanophosphor particle dispersion prepared in Example 1 and 0.2 g of cellulose fiber was applied to the recesses on the surface of the glass plate and vacuum dried to form a phosphor layer composed of inorganic nanophosphor particles. A wavelength conversion member was produced in the same manner as in Example 4 except that. With respect to the obtained wavelength conversion member, the light emission quantum efficiency was measured and found to be 43%.

(Example 8)
A cellulose fiber sheet (2 mm × 3 mm × 0.1 mm) was impregnated with 100 μl of the inorganic nanophosphor particle dispersion prepared in Example 1 and vacuum dried. The dried cellulose fiber sheet is sandwiched between the two glass plates obtained in Example 1 and thermocompression-pressed under the same conditions as in Example 1 so that the peripheral portions of the two glass plates melt together. As a result, a wavelength conversion member was obtained.

Example 9
An alumina sheet (2 mm × 3 mm × 0.1 mm) was impregnated with 100 μl of the inorganic nanophosphor particle dispersion prepared in Example 1 and vacuum dried. The dried alumina sheet was placed in the concave portion on the surface of the glass plate obtained in Example 4, and the other glass plate was stacked, and then thermocompression-pressed under the same conditions as in Example 4 to obtain 2 The peripheral portions of the glass plates were fused together to obtain a wavelength conversion member.

(Comparative example)
After pre-molding the mixture of glass powder and inorganic nanophosphor particles obtained in Example 2 into a cylindrical shape, heat treatment is performed at 200 ° C. for 20 minutes in a vacuum atmosphere, and the glass powder is sintered, thereby converting the wavelength conversion member. Got. With respect to the obtained wavelength conversion member, the light emission quantum efficiency was measured and found to be 1%.

DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 2nd board | substrate 1a, 2a Peripheral part 3 Phosphor layer 4 Mold 4a Upper mold 4b Lower mold 5 Reflective film 6 Band pass filter 10, 20, 30 Wavelength conversion member

Claims (17)

A first substrate and a second substrate;
A phosphor layer containing inorganic nanophosphor particles formed between the first substrate and the second substrate;
A wavelength conversion member having
The wavelength conversion member, wherein the first substrate and the second substrate are made of an inorganic material and are fused to each other.   The wavelength conversion member according to claim 1, wherein the first substrate and the second substrate are fused to each other at a peripheral edge portion.   The wavelength conversion member according to claim 1 or 2, wherein a yield point of at least one of the first substrate and the second substrate is 380 ° C or lower.   The wavelength conversion member according to any one of claims 1 to 3, wherein at least one of the first substrate and the second substrate is made of glass.   The wavelength conversion member according to claim 4, wherein the glass is Sn—P-based glass. The Sn—P-based glass is mol%, SnO 50-80%, P ₂ O ₅ 15-25% (however, 25% is not included), ZrO ₂ 0-3%, Al ₂ O ₃ 0-10. _{%, B 2 O 3 0~10%} , Li 2 O 0~10%, Na 2 O 0~10%, K 2 O 0~10%, Li 2 O + Na 2 O + K 2 O 0~10%, MgO 0~ 10%, CaO 0-3%, SrO 0-2.5%, BaO 0-2%, MgO + CaO + SrO + BaO 0-11% and ZrO ₂ + Al ₂ O ₃ + MgO 0-10%, SnO / P ₂ O ₅ It is 1.6-4.8, The wavelength conversion member of Claim 5 characterized by the above-mentioned.   The wavelength conversion member according to claim 4, wherein the glass is Sn—PF glass. The Sn-P-F-based glass, by ^{cationic%, Sn 2+ 10~90%, P} 5+ 10~70%, by ^{anionic%, O 2- 30~99.9%, F} - 0.1~70% The wavelength conversion member according to claim 7, comprising:   The inorganic nanophosphor particles are at least one selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, InP, GaN, GaAs, GaP, AlN, AlP, AlSb, InN, InAs, and InSb, or these two types The wavelength conversion member according to any one of claims 1 to 8, wherein the wavelength conversion member is a quantum dot phosphor made of the above composite.   The inorganic nanophosphor particles are inorganic particles composed of at least one selected from oxides, nitrides, oxynitrides, sulfides, oxysulfides, rare earth sulfides, aluminate chlorides, and halophosphates. The wavelength conversion member according to any one of claims 1 to 8, wherein:   The wavelength conversion member according to any one of claims 1 to 10, wherein the phosphor layer is formed by dispersing the inorganic nanophosphor particles in a glass matrix.   The wavelength conversion member according to claim 1, wherein a reflection film is formed on a surface of the first substrate on the phosphor layer side.   The wavelength conversion member according to any one of claims 1 to 12, wherein a band pass filter is formed on a surface of the first substrate on the phosphor layer side.   The wavelength conversion member according to claim 13, wherein the band-pass filter transmits excitation light and reflects fluorescence emitted from the phosphor layer.   The wavelength conversion member according to any one of claims 1 to 14, wherein an antireflection film is formed on a surface of the second substrate opposite to the phosphor layer.   A phosphor layer containing inorganic nanophosphor particles is sandwiched between the first substrate and the second substrate, and the first substrate and the second substrate are pressed by thermocompression using a mold. A method for producing a wavelength conversion member, comprising fusing a peripheral portion of a substrate.   The method for producing a wavelength conversion member according to claim 16, wherein the thermocompression pressing is performed at 400 ° C. or lower.