JP6486990B2 - Phosphor, method for producing the same, and light emitting device using the phosphor - Google Patents

Description

  The present invention relates to a phosphor, a manufacturing method thereof, and a light-emitting device using the phosphor.

  A light-emitting diode (LED) light-emitting device is mainly composed of a combination of an LED chip as an excitation light source and a phosphor, and various combinations of emission colors can be realized.

In a white LED light emitting device that emits white light, a combination of an LED chip that emits light in a blue region and a phosphor is used. For example, a combination of an LED chip that emits blue light and a phosphor mixture may be mentioned. As the phosphor, a yellow light emitting phosphor which is a complementary color of blue is mainly used, and it is used as a pseudo white light LED light emitting device. In addition, a three-wavelength white LED using an LED chip that emits blue light, a green or yellow light emitting phosphor, and a red light emitting phosphor has been developed. A K ₂ SiF ₆ : Mn phosphor is known as one of red light emitting phosphors used in such a light emitting device.

Special table 2009-528429 gazette

  An object of the present invention is to provide a red light-emitting phosphor that emits light when excited by light having an emission peak in a blue region, a method for producing the phosphor, and a light-emitting device using the phosphor. is there.

The red light-emitting phosphor according to one embodiment of the present invention is mainly composed of potassium silicofluoride, and the basic composition of the surface is represented by the following formula (A):
K _a SiF _{b (A)}
(Where 1.5 ≦ a ≦ 2.5 and 5.5 ≦ b ≦ 6.5)
The amount of manganese activated by manganese and present on the phosphor surface as measured by X-ray photoelectron spectroscopy is 0.2 with respect to the total amount of all elements present on the phosphor surface. It is not more than mol%, and the internal quantum efficiency η is not less than 60%.

A method for producing a phosphor according to an embodiment of the present invention includes:
Prepare an aqueous solution containing potassium permanganate and hydrogen fluoride as a reaction solution,
The Si source is immersed in the reaction solution for reaction,
After separating the formed phosphor, it is subsequently washed with a weak acid,
It includes rinsing the phosphor after washing.

  A light-emitting device according to an embodiment of the present invention includes a light-emitting element that emits light in a wavelength region of 440 nm to 470 nm and a phosphor layer containing the phosphor. It is.

The XPS spectrum of the fluorescent substance by embodiment. The XPS spectrum by narrow scan of Mn, K, F, Si contained in the phosphor according to the embodiment. The figure which shows the relationship between the manganese amount detected by XPS measurement, external quantum efficiency, and internal quantum efficiency. The figure which shows the change of the absorption spectrum of the fluorescent substance by the presence or absence of weak acid washing. The excitation spectrum of the fluorescent substance by embodiment. 1 is a cross-sectional view of a light emitting device according to an embodiment of the present invention. Sectional drawing of the light-emitting device concerning other embodiment of this invention. Sectional drawing of the light-emitting device concerning other embodiment of this invention. The figure which shows the Mn content rate in the surface, the absorptivity, internal quantum efficiency, and external quantum efficiency of the fluorescent substance by an Example and a comparative example.

  Hereinafter, embodiments of the present invention will be described in detail.

  Embodiments of the present invention will be described below. The embodiment described below shows a phosphor and a light emitting device for embodying the technical idea of the present invention, and the present invention is not limited to the following examples.

  Moreover, this specification does not specify the member shown by the claim as described embodiment. In particular, the size, material, shape, arrangement, and the like of the components described in the embodiments are not intended to limit the scope of the present invention, but are merely illustrative examples. It should be noted that the size and positional relationship of the members shown in each drawing may be exaggerated for clarity. Furthermore, the same name and reference numeral indicate the same or the same members, and detailed description thereof is omitted. Each element constituting the present invention may be composed of a plurality of elements by the same member, and the same member may be used as a plurality of elements. Conversely, the functions of the same member are shared by the plurality of members. It can also be realized.

  As a result of intensive studies and studies on a phosphor mainly composed of potassium silicofluoride and activated with manganese, the present inventors have found that there is a correlation between the surface composition of the phosphor and the emission characteristics of the phosphor. It was.

The red light-emitting phosphor according to the embodiment is a phosphor mainly made of potassium silicofluoride and activated with manganese. Here, the phosphor mainly composed of potassium silicofluoride refers to a phosphor in which the basic crystal structure of the phosphor is potassium silicofluoride and a part of the elements constituting the crystal is substituted with other elements. Although a very small amount of manganese exists on the surface of this phosphor, the basic composition of the surface is represented by the following formula (A).
K _a SiF _{b (A)}
Where
1.5 ≦ a ≦ 2.5, preferably 1.8 ≦ a ≦ 2.3, and 5.5 ≦ b ≦ 6.5, preferably 5.7 ≦ b ≦ 6.2.
The amount of manganese present on the surface of the phosphor is less than the amount of manganese relative to the entire phosphor, and is 0.2 mol% or less, preferably 0.1 mol%, based on the total amount of all elements present on the phosphor surface. Is

  Here, when a and b are within the above ranges, the phosphor can exhibit excellent luminous efficiency.

On the other hand, the phosphor according to the embodiment is preferably represented by the following formula (B) as a whole.
K _c (Si _1-x , Mn _x ) F _d (B)
Where 1.5 ≦ c ≦ 2.5, preferably 1.8 ≦ c ≦ 2.2,
5.5 ≦ d ≦ 6.5, preferably 5.7 ≦ d ≦ 6.2 and 0 <x ≦ 0.06, preferably 0.01 ≦ x ≦ 0.05
It is.

  The phosphor according to the embodiment contains manganese as an activator. When manganese is not contained (x = 0), light emission cannot be confirmed even when excited by light having an emission peak in the ultraviolet to blue region. Therefore, x in the formula (B) needs to be larger than 0. Moreover, when the manganese content increases, the luminous efficiency tends to be improved, and is preferably 0.01 or more. In order to obtain a phosphor emitting red light, the valence of manganese is preferably +4.

  However, when the manganese content is too large, a concentration quenching phenomenon occurs, and the emission intensity of the phosphor tends to be weakened. In order to avoid such inconvenience, the manganese content (x) is preferably 0.06 or less, and more preferably 0.05 or less.

  In order to analyze the content of each element with respect to the entire phosphor, for example, the following method may be mentioned. For metal elements such as K, Si, and Mn, the synthesized phosphor is alkali-melted and analyzed by ICP emission spectroscopy using, for example, an IRIS Advantage type ICP emission spectrometer (trade name, manufactured by Thermo Fisher Scientific). can do. Moreover, the nonmetallic element F can isolate | separate the fluorescent substance which was synthesize | combined by thermal hydrolysis, for example, can be analyzed with DX-120 type | mold ion chromatograph analyzer (a brand name, Nippon Dionex Co., Ltd. product). Further, F can be analyzed by ion chromatography after alkali melting as in the case of the metal element described above.

  The phosphor according to the embodiment does not contain oxygen stoichiometrically. However, oxygen may be inevitably mixed into the phosphor during the phosphor synthesis process or due to decomposition of the phosphor surface after synthesis. It is desirable that the oxygen content in the phosphor is zero, but if the ratio of [oxygen content] / [(fluorine content) + (oxygen content)] is less than 0.05, light emission It is preferable because the efficiency is not greatly impaired.

  In addition, the phosphor according to the embodiment may contain a small amount of an alkali metal element such as Na, Rb, or Cs, or another element such as Ti, Ge, or Sn. Even when these elements are contained in a small amount, the phosphor exhibits a similar emission spectrum and can achieve a desired effect. However, the content of these elements is preferably small from the viewpoint of the stability of the phosphor and the reactivity during phosphor synthesis. Further, when trying to synthesize a phosphor containing these elements, it may be necessary to change the synthesis procedure, and in order to reduce the manufacturing cost, a metal element other than the metal element included in the formula (B) is used. Preferably it is not.

  The phosphor according to the embodiment is characterized in that the amount of manganese present on the surface is small. Here, the surface of the phosphor means not only elements exposed on the surface of the phosphor but also a region having a depth of up to several tens of nm. Such a phosphor surface composition can be measured by X-ray photoelectron spectroscopy (XPS).

  XPS measurement is a technique for irradiating a sample with X-rays and measuring photoelectron energy emitted from the sample. Since the photoelectrons emitted from deep inside the sample are not scattered within the sample, they are not detected and the state near the surface can be evaluated. . Therefore, the XPS measurement can detect the surface state within several to several tens of nanometers of the sample.

Specifically, the XPS measurement can be performed by a Quantum-2000 type X-ray electron spectrometer (trade name, manufactured by ULVAC-PHI Co., Ltd.) or the like. The measurement conditions can vary depending on the type of phosphor to be measured, the particle shape, and the like. For example, the measurement can be performed under the following conditions.
X-ray source: AlKα ray, output: 40 W, measurement area: φ200 μm
Pass energy: Wide scan: 187.85 eV (1.60 eV / Step) Narrow scan: 58.70 eV (0.125 eV / Step)
Charge neutralizing gun: Use both e ⁻ and Ar ⁺ Extraction angle: 45 °

  When XPS measurement is performed on the phosphor according to the embodiment and an element detected from the obtained XPS spectrum is identified, impurities such as C or O are detected in addition to K, Si, and F elements constituting the phosphor. Sometimes. Further, Mn is not detected or is 0.2 mol% or less with respect to the total amount of all elements present on the phosphor surface even if detected. FIG. 1 shows an XPS spectrum by a wide scan for qualitative analysis of a phosphor according to the embodiment. FIG. 2 shows an XPS spectrum by narrow scan for Mn, K, F, and Si detected in the phosphor according to the embodiment. The composition values of Mn, K, F, and Si can be obtained from the peak areas detected in the spectrum for each element shown in FIG.

  The present inventors have found that a phosphor having an Mn content of 0.2 mol% or less with respect to all elements present on the surface detected by the XPS spectrum and having a basic composition of the surface represented by the formula (A) has an external quantum efficiency and We found a tendency to increase the internal quantum efficiency. In the phosphor according to the embodiment, the internal quantum efficiency is 60% or more.

式中
Ｅ（λ）：蛍光体へ照射した励起光源の全スペクトル（フォトン数換算）
Ｒ（λ）：蛍光体の励起光源反射光スペクトル（フォトン数換算）
Ｐ（λ）：蛍光体の発光スペクトル（フォトン数換算）
である。 Here, the external quantum efficiency η is a value calculated by multiplying the absorption rate α defined below and the internal quantum efficiency η ′.

In the formula, E (λ): the entire spectrum of the excitation light source irradiated to the phosphor (photon number conversion)
R (λ): Excitation light source reflected light spectrum of phosphor (photon number conversion)
P (λ): emission spectrum of phosphor (in terms of photon number)
It is.

  That is, the external quantum efficiency (η) can be calculated by (I) × (II).

  The external quantum efficiency, the internal quantum efficiency, and the absorptance can be measured by, for example, a C9920-02G type absolute PL quantum yield measuring apparatus (trade name, manufactured by Hamamatsu Photonics Co., Ltd.). Blue light having a peak wavelength of around 440 to 460 nm and a half-value width of 5 to 15 nm can be used as excitation light when measuring the light emission characteristics.

The relationship between the amount of manganese detected by XPS measurement, the external quantum efficiency, and the internal quantum efficiency is as shown in FIG. It can be seen that the efficiency, particularly the internal quantum efficiency, decreases as the amount of surface manganese detected increases.
According to the study by the present inventors, it has been found that the efficiency is lowered when the composition of the surface measured by XPS measurement is outside the composition range represented by the formula (A).

  The phosphor according to the embodiment can be manufactured by the following method. The method for producing a phosphor according to the embodiment is characterized by a washing step when taking out the synthesized phosphor in a synthesis method using a potassium permanganate reagent.

First, a reaction solution containing potassium permanganate (KMnO ₄ ), hydrogen fluoride (HF), and water is prepared.

This reaction solution preferably has a molar ratio of KMnO ₄ and HF in the range of 1/200 to 1/40. Further, the KMnO ₄ concentration of the solution is preferably 1% by mass or more. When the above range is exceeded, there may be a problem that the external quantum efficiency of the synthesized phosphor is lowered or a problem that the reactivity is lowered and a sufficient amount of the phosphor cannot be synthesized, resulting in high cost. Therefore, it is necessary to use a reaction solution in the above range.

  Moreover, about reaction temperature, it is generally possible to employ | adopt the temperature range of 20-80 degreeC. Regarding the reaction time, the optimum time varies depending on the reaction temperature and the shape of the Si raw material, but the optimum reaction time tends to be shorter as the reaction temperature is higher and the surface area of the Si raw material is larger.

  This reaction solution is brought into contact with a raw material that can be a Si source. In general, the reaction is performed by introducing Si raw material into the reaction solution. The reaction temperature is not particularly limited, but the higher the temperature, the better the reaction efficiency. Therefore, it is preferable to carry out the reaction at a higher temperature, but excessive temperature rise is not preferable from the viewpoint of production cost.

  The shape of the Si source is not particularly limited. However, since the phosphor formed on the surface of the Si source needs to be peeled off from the Si source as described later, it is preferably not in the form of fine powder. That is, in order to isolate the phosphor from the Si source, the volume of the Si source is preferably relatively large with respect to the volume of the phosphor to be formed. For example, it is possible to use a Si source in the form of particles, a plate-like material, or a rod-like material having a volume of 20000 times or more of the volume of the phosphor crystal to be formed. If a Si source having a large volume is used, the phosphor crystal formed on the surface is physically scraped off, or the phosphor crystal is separated from the Si source by ultrasonic vibration or the like and then separated by a sieve. It becomes possible. Specific examples include a silicon substrate such as a silicon wafer, granular amorphous silicon, a silicon dioxide film formed on the surface of the silicon substrate, and the like.

Next, the phosphor synthesized by the reaction is taken out of the reaction solution and washed with a weak acid-containing aqueous solution. By this washing, KMnO ₄ adhering to the phosphor surface is removed. According to the study by the present inventors, the efficiency of the phosphor synthesized by this washing is improved.
This is thought to be due to the following reasons. KMnO ₄ used as a raw material is ionized into K ⁺ and MnO ₄ ⁻ in an aqueous solution. It is known that the produced MnO ₄ ⁻ changes depending on the pH of the solution. Specifically, when the pH is in an acidic state, Mn ²⁺ is generated according to the following reaction formula.
MnO ₄ ⁻ + 8H ⁺ + 5e ⁻ → Mn ²⁺ + 4H ₂ O

On the other hand, when the pH of the solution is near neutral, MnO ₂ is generated according to the following reaction formula.
MnO ₄ ⁻ + 2H ₂ O + 3e ⁻ → MnO ₂ + 4OH ⁻

MnO ₂ produced by the above reaction has a black body color. Therefore, when MnO ₂ is generated on the phosphor surface, it is estimated that the phosphor emits light and reduces the internal quantum efficiency. In contrast, in the method for producing a phosphor according to the embodiment, after the synthesized phosphor is taken out of the reaction solution, the phosphor is subsequently washed with a weak acid aqueous solution, so that KMnO ₄ attached to the phosphor surface is removed. It is. As a result, the phosphor manufactured by the manufacturing method of the embodiment is considered to have excellent characteristics.

In order to remove KMnO ₄ by washing, it is also conceivable to use a strong acid such as hydrochloric acid, nitric acid or sulfuric acid. However, when such a strong acid is used, the surface of the K ₂ SiF ₆ crystal, which is a phosphor base material, is dissolved and the surface composition is changed, which tends to cause a problem that the luminous efficiency is lowered. For this reason, it is necessary to use a weak acid that hardly dissolves the phosphor matrix, for example, an acid having a pKa of 2 or more at 25 ° C. Specific examples of such weak acids include hydrofluoric acid, acetic acid, carbonic acid, and phosphoric acid. Of these, HF is particularly preferable because KMnO ₄ can be sufficiently removed and the phosphor matrix is hardly dissolved.

  Although the density | concentration of the weak acid aqueous solution used for washing | cleaning is not specifically limited, Generally 1-50 mass%, Preferably 5-40 mass% aqueous solution is used.

  In the method according to the embodiment, after washing with a weak acid, the phosphor is further rinsed with, for example, pure water, and the phosphor is further washed to remove the acid. This rinsing process is performed to remove unnecessary weak acid from the phosphor surface. Further, for example, HF is harmful, so it is preferable to remove it.

  Separation of the phosphor from the reaction solution, washing with a weak acid, and rinsing treatment can be performed, for example, on a filter disposed in a filter. That is, the reaction mother liquor is removed from the reaction mixture using a filter, the weak acid aqueous solution is applied to the phosphor particles remaining on the filter to wash the weak acid, the weak acid aqueous solution is removed, and pure water is further applied. A rinsing process can be performed.

  Absorption spectrum measurement was performed on a sample that had been subjected to weak acid washing using HF and a sample that had not been washed. The obtained result was as shown in FIG. In the sample subjected to the weak acid cleaning, it was confirmed that the phosphor of around 600 to 650 nm from which the phosphor emits light has little absorption, and the external quantum efficiency and the internal quantum efficiency are good. Specifically, more excellent luminous efficiency is achieved when the phosphor of the embodiment has an absorption rate of 600 to 650 nm of 10% or less.

A surface layer can also be formed on the surface of the phosphor particles thus produced by a coating process, for example, in order to improve moisture resistance and applicability during device fabrication. The material constituting the surface layer is selected from silicone resin, epoxy resin, fluororesin, tetraethoxysilane (TEOS), silica, zinc silicate, aluminum silicate, calcium polyphosphate, silicone oil, and silicone grease. The thing which consists of at least 1 type can be mentioned. Zinc silicate and aluminum silicate are represented by, for example, ZnO · cSiO ₂ (1 ≦ c ≦ 4) and Al ₂ O ₃ · dSiO ₂ (1 ≦ d ≦ 10), respectively. The surface layer does not need to be completely covered with the phosphor particle surface, and a part of the particle surface may be exposed. If the surface layer made of the material as described above exists on a part of the surface of the phosphor particle, the effect can be obtained even if the entire surface is not completely covered. The surface layer is disposed by immersing phosphor particles in the dispersion or solution for a predetermined time and then drying by heating or the like. In order to obtain the effect of the surface layer without impairing the original function as the phosphor, the surface layer is preferably present at a volume ratio of 0.1 to 5% of the phosphor particles.

  When the surface layer is formed as described above, if XPS measurement is performed on the phosphor particles, XPS measurement of the phosphor itself cannot be performed. Therefore, when measuring the surface composition of the phosphor particles, it is necessary to carry out it before performing the above-described surface treatment.

  Moreover, the phosphor according to the embodiment can be classified according to the coating method to the light emitting device to be used. When the particle size is prepared by classification, the physical stress on the crystal particles is small, so that the light emission characteristics are not lowered. In ordinary white LEDs using excitation light having an emission peak in the blue region, it is generally preferable to use phosphor particles classified to 1 to 50 μm. . If the particle size of the phosphor after classification is excessively small, the emission intensity may decrease. On the other hand, if the particle size is excessively large, the phosphor may be clogged in the phosphor layer coating device when it is applied to the LED, resulting in a decrease in work efficiency and yield, and color unevenness of the completed light emitting device.

The phosphor according to the embodiment of the present invention can be combined with a light emitting element having a light emission peak in the blue wavelength region to obtain the LED light emitting device according to the embodiment. The LED light emitting device according to the embodiment has higher emission intensity than the LED light emitting device using the conventional K ₂ SiF ₆ : Mn red phosphor.

  The phosphor according to the embodiment can be excited by an excitation light source having an emission peak in the ultraviolet to blue region. When this phosphor is used in a fermentation apparatus, as can be seen from the excitation spectrum of the phosphor according to the embodiment shown in FIG. 5, a light emitting element having an emission peak in the wavelength region of 440 nm to 470 nm is used as an excitation light source. It is desirable to do. Use of a light emitting element having a light emission peak outside the above wavelength range is not preferable from the viewpoint of light emission efficiency. As the light emitting element, a solid light source element such as an LED chip or a laser diode can be used.

  The phosphor according to the embodiment is a phosphor that emits red light. Therefore, a white light emitting device can be obtained by using in combination with a green light emitting phosphor and a yellow light emitting phosphor. The phosphor to be used can be arbitrarily selected according to the purpose of the light emitting device. For example, when a white light emitting device having a low color temperature is provided, a light emitting device having both efficiency and color rendering can be provided by combining the phosphor according to the embodiment and the yellow light emitting phosphor.

It can be said that the green light emitting phosphor and the yellow light emitting phosphor are phosphors having a main emission peak in a wavelength region of 520 nm to 570 nm. Examples of such phosphors include silicate phosphors such as (Sr, Ca, Ba) ₂ SiO ₄ : Eu, Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce, (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce, (Ca, Sr, Ba) Sulfide phosphors such as Ga ₂ S ₄ : Eu, (Ca, Sr, Ba) Si ₂ O ₂ N ₂ : Eu, (Ca , Sr) -αSiAlON and the like alkaline earth oxynitride phosphors. The main emission peak is a wavelength at which the peak intensity of the emission spectrum is maximized, and the emission peak of the exemplified phosphor has been reported in the literature so far. Note that a change in emission peak of about 10 nm may be observed due to the addition of a small amount of elements or a slight compositional change during the preparation of the phosphor, and such a phosphor is also included in the phosphors exemplified above. Shall.

  Further, in the light emitting device using the phosphor according to the embodiment, other than the above, a blue-green light emitting phosphor, an orange light emitting phosphor, and a red light emitting phosphor can be used according to applications.

As the orange-emitting phosphor and red-emitting phosphor, silicate phosphors such as (Sr, Ca, Ba) ₂ SiO ₄ : Eu, tungstate phosphors such as Li (Eu, Sm) W ₂ O ₈ , ( La, Gd, Y) ₂ O ₂ S: oxysulfide phosphors such as Eu, (Ca, Sr, Ba) S: sulfide phosphors such as Eu, (Sr, Ba, Ca) ₂ Si ₅ N ₈ : Examples thereof include nitride phosphors such as Eu and (Sr, Ca) AlSiN ₃ : Eu. By using these phosphors in combination with the phosphors according to the embodiments, not only the efficiency but also the color rendering properties for illumination applications and the color gamut for backlight applications can be further improved. However, if too many phosphors are used, the reabsorption phenomenon in which the phosphors absorb and emit light, and the phosphor emission is irradiated to the phosphors again, causing a scattering phenomenon, and the efficiency of the light emitting device decreases. To do.

  FIG. 6 shows a cross section of a light emitting device according to an embodiment of the present invention.

  In the illustrated light emitting device, the light emitting device 200 includes a lead 201 and a lead 202 formed by molding a lead frame, and a resin portion 203 formed integrally therewith. The resin portion 203 has a concave portion 205 whose upper opening is wider than the bottom portion, and a reflective surface 204 is provided on the side surface of the concave portion.

  A light emitting chip 206 is mounted with Ag paste or the like at the center of the substantially circular bottom surface of the recess 205. As the light-emitting chip 206, a chip that emits ultraviolet light or a chip that emits light in the visible region can be used. For example, it is possible to use semiconductor light emitting diodes such as GaAs and GaN. The electrodes (not shown) of the light emitting chip 206 are connected to the leads 201 and 202 by bonding wires 209 and 210 made of Au or the like, respectively. The arrangement of the leads 201 and 202 can be changed as appropriate.

  A fluorescent layer 207 is disposed in the recess 205 of the resin portion 203. The phosphor layer 207 can be formed by dispersing the phosphor 208 according to the embodiment in a ratio of 5 wt% or more and 50 wt% or less in a resin layer 211 made of, for example, a silicone resin. The phosphor can be attached by various binders such as an organic material resin and an inorganic material glass.

  As the binder for the organic material, a transparent resin excellent in light resistance such as an epoxy resin and an acrylic resin is suitable in addition to the above-described silicone resin. Low-melting glass using alkaline earth borate or the like as a binder for inorganic materials, such as ultrafine silica, alumina, etc., for attaching phosphors with large particle diameter, alkaline earth phosphate obtained by precipitation method Salt etc. are suitable. These binders may be used alone or in combination of two or more.

  Further, the phosphor used in the fluorescent layer can be coated on the surface as necessary. This surface coating prevents the phosphor from being deteriorated by external factors such as heat, humidity, and ultraviolet rays. Further, the dispersibility of the phosphor can be adjusted, and the phosphor layer can be easily designed.

  As the light emitting chip 206, a flip chip type having an n-type electrode and a p-type electrode on the same surface can be used. In this case, problems caused by the wires such as wire breakage and peeling and light absorption by the wires are solved, and a highly reliable and high-luminance semiconductor light-emitting device can be obtained. In addition, an n-type substrate may be used for the light emitting chip 206 to have the following configuration. Specifically, an n-type electrode is formed on the back surface of the n-type substrate, a p-type electrode is formed on the upper surface of the semiconductor layer on the substrate, and the n-type electrode or the p-type electrode is mounted on a lead. The p-type electrode or the n-type electrode can be connected to the other lead by a wire. The size of the light emitting chip 206 and the size and shape of the recess 205 can be changed as appropriate.

  FIG. 7 shows a cross-sectional view of a light emitting device according to another embodiment of the present invention. The illustrated light emitting device includes a light emitting device 100, a semiconductor light emitting element 106F mounted thereon, and a sealing body 111 covering the semiconductor light emitting element 106F. The light emitting device 100 includes leads 101 and 102 formed from a lead frame, and a resin portion 103 molded integrally therewith. The leads 101 and 102 are arranged so that one ends of the leads 101 and 102 face each other. The other ends of the leads 101 and 102 extend in opposite directions and are led out from the resin portion 103 to the outside.

  An opening 105 is provided in the resin portion 103, and a protective Zener diode 106 E is mounted on the bottom surface of the opening by an adhesive 107. A semiconductor light emitting element 106F is mounted on the protective Zener diode 106E. That is, the diode 106E is mounted on the lead 101. A wire 109 is connected to the lead 102 from the diode 106E.

  The semiconductor light emitting element 106F is surrounded by the inner wall surface of the resin portion 103, and this inner wall surface is inclined toward the light extraction direction and acts as a reflection surface 104 that reflects light. The sealing body 111 filled in the opening 105 contains the phosphor 110. The semiconductor light emitting element 106F is stacked on the protective Zener diode 106E. As the phosphor 110, the phosphor according to the embodiment of the present invention is used.

  FIG. 8 shows an example of a bullet-type light emitting device. The semiconductor light emitting element 51 is mounted on the lead 50 ′ via the mount material 52 and covered with the pre-dip material 54. A lead 50 is connected to the semiconductor light emitting element 51 by a wire 53 and is enclosed by a casting material 55. The pre-dip material 54 contains the phosphor according to the embodiment.

As described above, the light emitting device according to the embodiment, for example, the white LED is used not only for general illumination, but also as a light emitting device used in combination with a filter such as a color filter and the light emitting device, for example, a light source for a liquid crystal backlight. Is also optimal. Specifically, it can also be used as a red light emitting material for an inorganic electroluminescent device using a liquid crystal backlight source or a blue light emitting layer.
EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further in detail, this invention is not limited to a following example, unless the meaning is exceeded.

Examples 1-3 and Comparative Examples 1-2
A commercially available Si single crystal was prepared as a raw material. Further, 10.8 g of KMnO ₄ powder was sufficiently mixed with 200 ml of HF aqueous solution (49%) in 200 ml of mixed solution to obtain a reaction solution. The Si single crystal was reacted in the reaction solution at room temperature (20 ° C.) for 80 minutes. At this time, the reaction solution was stirred slowly to make the reaction solution uniform. The obtained phosphor was separated, washed with a weak acid with an aqueous HF solution (6% by mass), and further washed with pure water to obtain the phosphor of Example 1. As a result of performing composition analysis on this phosphor, it was found that the composition of the phosphor was K _2.1 (Si _0.98 , Mn _0.02 ) F _5.8 composition. Further, the crystal structure was identified as K ₂ SiF ₆ from the diffraction pattern obtained by XRD measurement. Furthermore, the Mn content on the phosphor surface was 0%.

  The phosphors of Examples 2 and 3 and Comparative Examples 1 and 2 were synthesized by changing the concentration of the HF aqueous solution used for washing, the number of washings, and the like. The obtained phosphor had the Mn content, absorption rate, internal quantum efficiency, and external quantum efficiency on the surface as shown in Table 1 and FIG.

Example 4 and Comparative Examples 3 to 5
A phosphor was manufactured in the same manner as in Example 1 except that the acid used for the weak acid washing after separation from the reaction solution was changed. About the obtained fluorescent substance, the relative yield, the relative quantum efficiency, and the relative luminous efficiency with respect to the fluorescent substance of Example 1 were measured. The obtained results were as shown in Table 2.

DESCRIPTION OF SYMBOLS 200 ... Resin system; 201 ... Lead; 202 ... Lead; 203 ... Resin part 204 ... Reflecting surface; 205 ... Recessed part; 206 ... Light emitting chip 207 ... Fluorescent layer; 208 ... Phosphor; ... resin layer;
DESCRIPTION OF SYMBOLS 100 ... Resin stem; 101 ... Lead 102 ... Lead; 103 ... Resin part; 104 ... Reflecting surface; 105 ... Opening 106E ... Zener diode; 107 ... Adhesive 109 ... Bonding wire; 110 ... Phosphor; Body 142 ... bump; 144 ... bump;
50, 50 '... Lead; 51 ... Semiconductor light emitting element; 52 ... Mounting material 53 ... Bonding wire; 54 ... Pre-dip material; 55 ... Casting material.

Claims (15)

It consists mainly of potassium silicofluoride, and the basic composition of the surface is the following formula (A):
K _a SiF _{b (A)}
(Where 1.5 ≦ a ≦ 2.5 and 5.5 ≦ b ≦ 6.5)
The amount of manganese activated by manganese and existing on the surface of the phosphor is less than the amount of manganese with respect to the entire phosphor, and is measured by X-ray photoelectron spectroscopy A red-emitting phosphor characterized in that the amount of manganese present on the surface is 0.2 mol% or less with respect to the total amount of all elements present on the phosphor surface, and the internal quantum efficiency η is 60% or more. The composition formula of the whole phosphor is the following formula (B):
K _c (Si _1-x , Mn _x ) F _d (B)
(Where 1.5 ≦ c ≦ 2.5, 5.5 ≦ d ≦ 6.5, and 0 <x ≦ 0.05
Is)
The phosphor according to claim 1, represented by:   The phosphor according to claim 1 or 2, wherein the phosphor has an absorptance of 600 to 650 nm of 10% or less. Prepare an aqueous solution containing potassium permanganate and hydrogen fluoride as a reaction solution,
The Si source is immersed in the reaction solution for reaction,
After separating the formed phosphor, it is subsequently washed with hydrogen fluoride,
The manufacturing method of the fluorescent substance of any one of Claims 1-3 including carrying out the rinse process of the fluorescent substance after washing | cleaning.   The process according to claim 4, wherein the reaction time is 20 to 80 minutes. Si source, a single crystal silicon, is selected from polycrystalline silicon, and amorphous silicon or Ranaru group, The method of claim 4 or 5.   The method according to claim 4, wherein the Si source is a silicon substrate.   The method according to any one of claims 4 to 7, wherein a molar ratio of potassium permanganate and hydrogen fluoride in the reaction solution is 1/200 to 1/40.   The method according to any one of claims 4 to 8, wherein the potassium permanganate concentration in the reaction solution is 1% by mass or more.   A light emitting device comprising: a light emitting element that emits light in a wavelength region of 440 nm to 470 nm; and a phosphor layer containing the phosphor according to claim 1. The light emitting device according to claim 10, wherein the phosphor layer includes a phosphor having a main emission peak in a wavelength region of 520 nm or more and 570 nm or less.   The light emitting device according to claim 10 or 11, wherein the phosphor layer further includes a green light emitting phosphor or a yellow light emitting phosphor. The green light-emitting phosphor or the yellow light-emitting phosphor is (Sr, Ca, Ba) ₂ SiO ₄ : Eu, Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce, (Y, Gd) ₃ (Al, _{Ga) 5 O 12: Ce,} (Ca, Sr, Ba) Ga 2 S 4: Eu, (Ca, Sr, Ba) Si 2 O 2 N 2: Eu, and (Ca, from the group consisting of Sr) -αSiAlON The light emitting device according to claim 12, which is selected.   The light emitting device according to claim 10, wherein the phosphor layer further includes an orange light emitting phosphor or a red light emitting phosphor. The orange-emitting phosphor or red-emitting phosphor is (Sr, Ca, Ba) ₂ SiO ₄ : Eu, Li (Eu, Sm) W ₂ O ₈ , (La, Gd, Y) ₂ O ₂ S: Eu. , (Ca, Sr, Ba) S: Eu, (Sr, Ba, Ca) ₂ Si ₅ N ₈ : Eu, and (Sr, Ca) AlSiN ₃ : Eu. 14. The light emitting device according to 14.

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