JP5391946B2 - Phosphor, light emitting device using the same, and method for producing phosphor - Google Patents

Description

  The present invention relates to a phosphor that is efficiently excited by near-ultraviolet light, a light-emitting device using the phosphor, and a method for manufacturing the phosphor, and more specifically, a yellow-emitting phosphor that is efficiently excited by near-ultraviolet light and the phosphor. The present invention relates to a light emitting device and a method for manufacturing a phosphor.

  LED lamps using light emitting diodes (LEDs) are used in many fields such as signal lamps, mobile phones, various types of lighting, in-vehicle displays, and various types of display devices. In addition, white LED light-emitting devices formed by combining LEDs and phosphors have been actively applied to backlights of liquid crystal displays, small strobes, and the like. Recently, the white light emitting device has been tried to be used for a lighting device, and is expected to be an alternative light source for a fluorescent lamp with a small environmental load by taking advantage of its long life and mercury free.

  As a configuration of a light emitting device that emits white light, a combination of a blue light emitting LED and a yellow light emitting phosphor can be used (see, for example, Patent Document 1). This is to allow white light to be obtained by mixing blue light from the LED and yellow light obtained by converting a part of the blue light emitted from the LED with a yellow light emitting phosphor. is there. Therefore, as a phosphor, there is a demand for a phosphor that is efficiently excited by blue light having a wavelength of 420 nm to 470 nm emitted from an LED and emits yellow light.

  However, in this configuration, since blue light having a wavelength of 420 nm to 470 nm uses transmitted light that is not absorbed by the phosphor, a difference in the amount of transmitted blue light occurs in the amount of phosphor and the thickness of the phosphor layer. There was a problem that the color variation was large.

  For this reason, as a configuration of a white light emitting device, an ultraviolet light LED having a wavelength range of 350 nm to 420 nm, a blue light emitting phosphor excited by the LED, and a yellow light emitting that is excited by the LED and hardly excited by blue light. A combination of phosphors is exemplified (for example, see Patent Document 2). In such a configuration, if the ratio of various phosphors is controlled, even if there is a change in the total amount of the phosphor or a difference in the thickness of the phosphor layer, the blue light and the yellow light are kept almost constant, resulting in color variations. It is hard to occur. Therefore, in this method, a highly efficient phosphor that emits blue and yellow light that can be excited by near-ultraviolet light in a wavelength range of 350 nm to 420 nm is required.

  However, yellow light-emitting phosphors that can be excited at wavelengths in the near-ultraviolet region and have high efficiency have not yet been put into practical use. For this reason, in the field of white light emitting devices as described above, it has been particularly desired to develop a yellow light emitting phosphor that can be practically used with high efficiency.

JP 2008-274240 A JP 2009-38348 A

  The present invention has been made in view of the above points, and its main purpose is to efficiently emit near-ultraviolet light, particularly light having an emission spectrum having a peak wavelength in the range of 540 to 600 nm. An object of the present invention is to provide a phosphor that emits light, a manufacturing method thereof, and a light-emitting device using the phosphor.

Means for Solving the Problems and Effects of the Invention

  As a result of intensive studies, the present inventors have found that the above problem can be solved by a phosphor having a specific elemental composition ratio, and have completed the present invention.

That is, according to the phosphor of the present invention, it is possible to represent the set formed by the following general formula.

_{Ca x1 Sr x2 Re y Eu z} Si 6 O a Cl b
(In the above formula, Re is at least one selected from the group consisting of Sc, Y, La, Ce, Pr, Gd, Tb, Dy, Ho, Tm, and Lu;
2 ≦ x1 ≦ 3
3 ≦ x2 ≦ 4
5.0 ≦ x1 + x2 ≦ 7.0,
0 <y <0.05 ,
0 <z ≦ 1.5,
a = (x1 + x2) + (3/2) y + z + 12− (1/2) b,
1.0 ≦ b ≦ 2.0. )

  As a result, a phosphor capable of emitting yellow light when excited with excitation light in the near ultraviolet region can be obtained. In addition, a phosphor having a wide half-value width of the emission spectrum, high brightness, excellent temperature characteristics, and excellent temperature characteristics with little color shift and low brightness at high temperatures can be obtained.

  A part of the Ca and Sr may be substituted with one or more elements selected from the group consisting of Mg, Ba, Zn, and Mn.

  The peak wavelength of the emission spectrum can be set to a wavelength range of 540 to 600 nm by being excited by light having a wavelength range of 350 nm to 420 nm. As a result, a phosphor capable of emitting yellow light when excited with excitation light in the near ultraviolet region can be obtained.

  Based on the luminance of the phosphor at room temperature, the luminance of the phosphor when heated to 200 ° C. can be 56% or more. As a result, it is possible to obtain a phosphor excellent in temperature characteristics in which the luminance is hardly lowered even at high temperatures.

  At least 50% by weight or more can have crystals. Thereby, the light emission luminance can be increased and the processability of the phosphor is improved.

  The particle size of the phosphor can be in the range of 2 μm to 50 μm. Thereby, the advantage which can suppress the color nonuniformity at the time of using fluorescent substance for a light-emitting device is acquired.

  Absorbs at least part of the light from the excitation light source that emits light on the short-wavelength side of visible light from the near ultraviolet region, the first phosphor composed of the phosphor, and the excitation light source, and peaks at 420 nm to 480 nm. One or more types of second phosphors that emit fluorescence having a wavelength and a translucent resin containing the first and second phosphors can be used. Thereby, a high-quality light-emitting device with suppressed color unevenness can be obtained.

  The second phosphor has a larger central particle diameter than the first phosphor, and the second phosphor is distributed in the vicinity of the excitation light source in the translucent resin to form a color conversion layer. One phosphor can be distributed outside the color conversion layer in the translucent resin. Thereby, color conversion can be efficiently performed by the color conversion layer constituted by the second phosphor, and color unevenness can be suppressed by the first phosphor dispersed on the outside thereof.

  As said 2nd fluorescent substance, an apatite or a BAM type fluorescent substance and a silicate type fluorescent substance can be included.

The second phosphor may include Ca ₅ (PO ₄ ) ₃ (Cl, Br): Eu or BaMgAl ₁₀ O ₁₇ : Eu, (Sr, Ba, Ca) ₃ MgSi ₂ O ₈ : Eu.

  According to the method for producing a phosphor according to the present invention, a simple substance, an oxide, a nitride, or a carbonate containing an element contained in the composition represented by the following general formula is prepared and ground so as to contain chlorine. And / or mixing step, filling the obtained raw material in a crucible and firing in a reducing atmosphere, solid-liquid separation of the fired raw material, drying, pulverizing, dispersing and filtering to obtain the desired fluorescence A step of obtaining a body powder, and alkaline earth metal chloride can be added as a flux during the firing.

_{Ca x1 Sr x2 Re y Eu z} Si 6 O a Cl b
(In the above formula, Re is at least one selected from the group consisting of Sc, Y, La, Ce, Pr, Gd, Tb, Dy, Ho, Tm, and Lu;
2 ≦ x1 ≦ 3
3 ≦ x2 ≦ 4
5.0 ≦ x1 + x2 ≦ 7.0,
0 <y <0.05 ,
0 <z ≦ 1.5,
a = (x1 + x2) + (3/2) y + z + 12− (1/2) b,
1.0 ≦ b ≦ 2.0. )

  As a result, a phosphor capable of emitting yellow light when excited with excitation light in the near ultraviolet region can be obtained. In addition, a phosphor having a wide half-value width of the emission spectrum, high brightness, excellent temperature characteristics, and excellent temperature characteristics with little color shift and low brightness at high temperatures can be obtained. Moreover, the reactivity can be improved, it can act as a flux, and the reaction promotion effect can be acquired.

The alkaline earth metal chloride can be SrCl ₂ . Thereby, since the melting point is low and the reactivity can be promoted, there is an advantage that the particle size of the phosphor can be controlled regardless of the temperature.

4 is a graph showing emission spectra of phosphors according to Example 1 and Comparative Example 1. 6 is a graph showing reflection spectra of phosphors according to Example 1 and Comparative Example 1. 6 is a graph showing excitation spectra of phosphors according to Example 1 and Comparative Example 1. It is an image figure which shows the electron micrograph of the fluorescent substance which concerns on Example 1 and Comparative Example 1. FIG. 22 is a schematic cross-sectional view of a light emitting device according to Example 19. FIG. It is a graph which shows the emission spectrum of the light-emitting device of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a phosphor for embodying the technical idea of the present invention, a method for manufacturing the phosphor, and a light emitting device using the phosphor. The manufacturing method and the light emitting device using this phosphor are not specified as follows. Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely explanations. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing. In addition, the contents described in some examples and embodiments may be used in other examples and embodiments.

The relationship between the color name and chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, and the like comply with JIS Z8110. Specifically, 380 nm to 455 nm is blue purple, 455 nm to 485 nm is blue, 485 nm to 495 nm is blue green, 495 nm to 548 nm is green, 548 nm to 573 nm is yellow green, 573 nm to 584 nm is yellow, 584 nm to 610 nm is yellow red , 610 nm to 780 nm is red.
(Embodiment 1)

Phosphor according to Embodiment 1, the general formula is represented by _{Ca x1 Sr x2 Re y Eu z} Si 6 O a Cl b. In this formula, Re is at least one selected from the group consisting of Sc, Y, La, Ce, Pr, Gd, Tb, Dy, Ho, Tm, and Lu, Eu is europium, and Si is silicon. Further, 2 ≦ x1 ≦ 3, 3 ≦ x2 ≦ 4, 5.0 ≦ x1 + x2 ≦ 7.0, 0 <y <0.05 , 0 <z ≦ 1.5, a = (x1 + x2) + (3/2 ) Y + z + 12− (1/2) b, 1.0 ≦ b ≦ 2.0. Further, in this phosphor, Eu, which is a rare earth, becomes the emission center.

  A part of Ca and Sr may be substituted with one or more elements selected from the group consisting of Mg, Ba, Zn and Mn.

  This phosphor absorbs light in the short wavelength region of visible light from near ultraviolet rays, and emits light having the emission peak wavelength of the phosphor longer than the emission peak wavelength of excitation light. That is, the main emission peak is efficiently excited by near ultraviolet light, and light having an emission spectrum peak at 540 to 600 nm is efficiently emitted. Therefore, by using this phosphor in combination with a phosphor emitting blue light from near-ultraviolet light, a light emitting device with high luminous efficiency and hardly depending on the thickness of the phosphor layer can be formed.

  In the present specification, the short wavelength region from the near ultraviolet region to the visible light is not particularly limited, but refers to a region of 240 to 420 nm. Specifically, it is preferable to use an excitation light source in the range of 290 nm to 410 nm.

Moreover, it is preferable that at least a part of the phosphor has a crystal. For example, since the glass body (amorphous) has a loose structure, the component ratio in the phosphor is not constant, and chromaticity may be uneven. Therefore, in order to avoid this, it is necessary to control the reaction conditions in the production process to be strictly uniform. On the other hand, since the phosphor according to the first embodiment can be made of powder or particles having crystallinity instead of a glass body, it is easy to manufacture and process. Further, this phosphor can be uniformly dissolved in an organic medium, and adjustment of a light emitting plastic or a polymer thin film material can be easily achieved. Specifically, in the phosphor according to Embodiment 1, at least 50 wt% or more, more preferably 80 wt% or more has crystals. This indicates the proportion of the crystalline phase having luminescent properties, and if it has a crystalline phase of 50% by weight or more, light emission that can withstand practical use can be obtained. Therefore, the more crystal phases, the better. Thereby, the light emission luminance can be increased and the workability is improved.
(Particle size)

  In consideration of mounting in a light emitting device, the particle diameter of the phosphor is preferably in the range of 2 μm to 50 μm, more preferably 5 μm to 30 μm. Moreover, it is preferable that the phosphor having this central particle size value is contained with high frequency. Furthermore, the particle size distribution is preferably distributed in a narrow range. By using a phosphor having a large particle size with small variations in particle size and particle size distribution and having optically excellent characteristics, a light emitting device having a favorable color tone can be obtained with further suppressed color unevenness. Therefore, a phosphor having a particle size in the above range has high light absorption and conversion efficiency. On the other hand, a phosphor having a particle size smaller than 2 μm tends to form an aggregate.

  In the case of a light emitting device in which a phosphor is combined with an excitation light source such as an LED chip, a color conversion layer is formed by being dispersed in a translucent resin and distributed in the vicinity of the LED chip. At this time, in addition to making the particle size of the phosphor close to uniform, it is also possible to combine a phosphor with a small particle size and a phosphor with a large particle size. In this case, it is preferable to distribute phosphors having a small particle diameter outside the color conversion layer. Thereby, color conversion can be efficiently performed by the color conversion layer constituted by the large particle size phosphor, and color unevenness can be suppressed by the small particle size fluorescent material dispersed on the outside thereof.

  Specifically, the phosphor described above is used as the first phosphor, and in addition to this, one or more second types that are excited by absorbing light from the same excitation light source and emit fluorescence having a peak wavelength at 420 nm to 480 nm. A phosphor is combined and contained in a translucent resin. This second phosphor has a larger center particle size than the first phosphor.

As such a large particle size phosphor, one having a center particle size adjusted to a range of 10 μm to 60 μm is used. For example, Ca ₅ (PO ₄ ) ₃ (Cl, Br): Eu apatite phosphor having a center particle diameter of about 13 μm, BaMgAl ₁₀ O ₁₇ : Eu BAM phosphor, (Sr, Ba, Ca) ₃ MgSi ₂ O ₈ : Eu, CaMgSi ₂ O ₆ : Eu silicate phosphor, Y _2.965 Al ₅ O ₁₂ : Ce _0.035 aluminate phosphor, etc. can be used. As the phosphor having a small particle diameter, a phosphor having a center particle diameter adjusted to a range of 0.2 μm to 8 μm is used. For example, the phosphor of 5 to 7 μm is used. Or you may adjust to a smaller particle size, for example, the center particle size of a 1st fluorescent substance is set to the range of 0.2 micrometer-1.5 micrometers. Thereby, color conversion can be efficiently performed by the color conversion layer constituted by the second phosphor, and color unevenness can be suppressed by the first phosphor dispersed on the outside thereof. That is, the yellow light-emitting phosphor particles are dispersed in the blue light-emitting phosphor particles, and the phosphor can be filled with high density. As a result, it becomes easy to irradiate the excitation light directly to the yellow light emitting phosphor. Conversely, the second phosphor, BAM phosphor, apatite phosphor, silicate phosphor (for example, Ca ₅ (PO ₄ ) ₃ (Cl, Br): Eu, BaMgAl ₁₀ O ₁₇ : Eu, ( Sr, Ba, Ca) ₃ MgSi ₂ O ₈ : Eu) emits light from the excitation light source efficiently because the yellow light emitting phosphor is hardly excited by the blue light near 460 nm emitted from the light. Thus, the excitation of the yellow light-emitting phosphor can be effectively realized by being positioned outside the blue light-emitting phosphor. Conversely, if the phosphors have the same particle size for the yellow light emitting phosphor and the blue light emitting phosphor, a gap is likely to be generated between the phosphors, and the excitation light is likely to leak. In particular, in the present embodiment, near ultraviolet light is used as the excitation light source instead of visible light, so it is important to effectively use the excitation light inside the light emitting device without leaking the excitation light to the outside. For this reason, the advantage which can utilize excitation light effectively as mentioned above is acquired by using the combination of the fluorescent substance of a different particle size.
(Production method)

Next, a method for manufacturing the phosphor according to Embodiment 1 will be described. Phosphors are made from simple elements, oxides, carbonates or nitrides of the elements contained in the composition, and some of the prescribed chlorine is scattered or eluted from each raw material. Chlorine can be adjusted. Additive materials such as flux are appropriately added to these raw materials, and they are mixed wet or dry using a mixer. The mixer can be pulverized using a pulverizer such as a vibration mill, a roll mill, a jet mill, or the like, in addition to a ball mill that is usually used industrially, to increase the specific surface area. In addition, in order to keep the specific surface area of the powder within a certain range, classification is performed using industrially used sedimentation tanks, hydrocyclones, centrifuges and other wet separators, cyclones, air separators and other dry classifiers. You can also.
(Baking)

The mixed raw materials are packed in a crucible made of SiC, quartz, alumina, BN or the like and fired in a reducing atmosphere of N ₂ and H ₂ . As the firing atmosphere, an argon atmosphere, an ammonia atmosphere, or the like can also be used. Firing is performed at a temperature of 1000 ° C. to 1150 ° C. for 1 hour to 30 hours.
(Crushing etc.)

  Next, the fired product is pulverized, dispersed, filtered, etc. to obtain the desired phosphor powder. Solid-liquid separation can be performed by industrially used methods such as filtration, suction filtration, pressure filtration, centrifugation, and decantation. Drying can be performed by industrially used apparatuses such as a vacuum dryer, a hot-air heating dryer, a conical dryer, and a rotary evaporator.

Regarding the phosphor raw material, the purity of SiO ₂ as the raw material is preferably 2N or higher, but may contain different elements such as Li, Na, K, B, and Cu. Furthermore, a part of Si can be replaced with Ge and Sn.

Alkaline earth Mg, Ca, Sr, and Ba can be used in combination with halogen salts and oxides, carbonates, phosphates, silicates, and the like to achieve a predetermined halogen ratio. In addition, when a halogen is introduced, an ammonium salt containing a halogen can be used instead of the alkaline earth halogen salt.
(Activator)

Further, Eu as the activator is preferably used alone, but halogen salts, oxides, carbonates, phosphates, silicates and the like can be used. Moreover, when using the mixture which requires Eu, a compounding ratio can be changed as desired. Thus, by replacing a part of Eu with another element, the other element acts as a co-activation. As a result, the color tone can be changed, and the light emission characteristics can be adjusted. Europium mainly has bivalent and trivalent energy levels, but the phosphor of Embodiment 1 uses Eu ²⁺ as an activator.

Further, a Eu compound may be used as a raw material. In this case, it is better to use a purified raw material, but a commercially available product may be used. Specifically, europium oxide Eu ₂ O ₃ , metal europium, europium nitride, and the like can be used as Eu compounds. The raw material Eu may be an imide compound or an amide compound. Europium oxide preferably has a high purity, and commercially available products can also be used.

  Furthermore, it is preferable that the rare earth element to be added other than Eu is usually added in the form of an oxide or hydroxide, but is not limited thereto, and is not limited to chloride, bromide, iodide, fluoride, phosphate. , Carbonates, sulfates or other inorganic salts may be used, or they may be contained in other raw materials in advance.

  The raw material is preferably purified. Thereby, since a purification process is not required, the manufacturing process of the phosphor can be simplified, and an inexpensive phosphor can be provided.

  Hereinafter, as an example of the phosphor according to the embodiment, a phosphor, a light emitting device using the phosphor, and a method for manufacturing the phosphor will be described.

  Table 1 shows the light emission characteristics of the phosphors of Examples 1 to 18 and Comparative Examples 1 to 9. Specifically, the charged composition of each phosphor, the particle size of the obtained phosphor, and the light emission characteristics when excited at a wavelength of 400 nm, the chromaticity (x, y), and Comparative Example 1 as a reference (100%) Relative luminance Y (%) was evaluated. FIG. 1 shows emission spectra of phosphors according to Example 1 and Comparative Example 1. FIG. 2 shows the reflection spectrum. FIG. 3 shows the excitation spectrum. FIG. 4 shows a photomicrograph of the phosphor.

  In Examples 1 to 18, it was confirmed that the luminance was improved as compared with the comparative example. Moreover, the particle size of the phosphors according to Examples 1 to 18 could be reduced as compared with the comparative example. This is probably because the reaction of the phosphor was suppressed by adding rare earth.

In Example 1, in the charged composition ratio, Ca: Sr: Sc: Eu: Si: Cl = 2.56: 5.03: 0.03: 0.6: 6.0: 5.62 (Sr and Cl are Each raw material is weighed so that SrCl ₂ becomes a flux component and is charged in excess of a given composition.

Specifically, the following powders were weighed as the phosphor material of Example 1. However, the purity of each phosphor material is assumed to be 100%.
Calcium carbonate (CaCO ₃ ) ... 8.31 g
Strontium carbonate (SrCO ₃ ) ... 41.71 g
Calcium chloride (CaCl ₂ ) ... 15.47g
Strontium chloride (SrCl ₂ ) ... 14.02 g
Europium oxide (Eu ₂ O ₃ ) ... 7.78 g
Scandium oxide (Sc ₂ O ₃ ) 0.15 g
Silicon oxide (SiO ₂ ) ... 26.57 g

The weighed raw materials are thoroughly mixed in a dry manner by a ball mill, further packed in a crucible, and baked at 1100 ° C. for 4 hours in a reducing atmosphere. The fired product was pulverized and washed with water to obtain a phosphor powder. Although the exact composition and composition ratio of the phosphor are unknown, since SrCl ₂ is present in excess, Cl ₂ is washed away by water washing, so that the actual composition after water washing is (Ca, Sr, Re, Eu). ) ₇ Si ₆ O ₁₈ Cl ₂ Thus, the charged composition and the actual composition seem to be greatly different.

As described above, broad fluorescence emission having a wide half-value width could be obtained. Thereby, it is possible to obtain light emission having sufficient color rendering properties without adding a red light emitting phosphor. However, it goes without saying that phosphors emitting red fluorescence can be mixed in order to further improve color rendering. As such a red light emitting phosphor, (Ca, Sr) ₂ Si ₅ N ₈ : Eu, (Ca, Sr) AlSiBN ₃ : Eu, 0.5 MgF ₂ .3.5MgO · GeO ₂ : Mn, Ln ₂ O A phosphor such as ₂ S: Eu (Ln = Y, La, Gd, etc.) can be suitably used. For example, the general formula _{M x Al y Si z O a} N b: Eu 2+ (0.5 ≦ x ≦ 3,0.5 ≦ y ≦ 3,0.5 ≦ z ≦ 9,0 ≦ a ≦ 3, 0.5 ≦ b ≦ 3), and M is at least one selected from the group consisting of Mg, Zn, Ca, Sr, and Ba.

In the same manner as in Example 1, the raw materials were adjusted and synthesized so as to have a predetermined blending ratio. As a result, the luminance using a certain rare earth and the added amount was improved by up to 11%. Thus, a yellow phosphor with high luminance can be obtained even by excitation at 405 nm. In particular, Sc, Y, La, Ce, Tb, and Ho showed good luminance even when the addition amount was large.
(Temperature characteristics)

  Table 2 shows the relative luminance of each phosphor when heated to 100 ° C. and 200 ° C. with the luminance at room temperature (about 27 ° C.) of each phosphor as a reference (100%). From this table, it was confirmed that the deterioration of luminance at high temperature was suppressed as compared with the comparative example, that is, the phosphor was excellent in temperature characteristics and did not easily decrease in luminance even at high temperature.

  The temperature characteristic indicates whether or not the phosphor exhibits high emission characteristics when a phosphor is provided on the surface of the light emitting element. The higher the relative luminance (%), the better the temperature characteristic and the more stable the phosphor. Is shown. In particular, part of the current supplied to the light emitting element becomes heat, and when the phosphor absorbs light emitted from the light emitting element and emits light, part of the light emission loss of the phosphor also becomes heat. For this reason, since the vicinity of the phosphor becomes a relatively high temperature, the better the temperature characteristics, the more reliable the white light emitting device can be made. From this result, it can be confirmed that the phosphor according to the example has better temperature characteristics and higher reliability than the comparative example. In particular, Examples 11 to 13 and 18 show higher numerical values than the comparative examples, and the temperature characteristics are excellent. From these results, it was confirmed that the temperature characteristics were improved by about 5 to 10%.

Furthermore, Table 3 shows the analysis value of the obtained phosphor and the composition ratio obtained from the analysis value when Si = 6. From this table, it can be seen that the charged composition and the actual composition actually obtained differ greatly. In particular, since SrCl ₂ is present in a considerably excessive amount, the substantial composition (chemical formula) after washing with water seems to be (Ca, Sr, Re, Eu) ₇ Si ₆ O ₁₈ Cl ₂ . From the elemental analysis values, it is considered that some alkali metals, rare earth elements, and halogens are less than the substantial composition.

(Light emitting device)

  Hereinafter, light emitting devices employing the phosphors according to the above-described embodiments will be described as Examples 19 and 20. FIG. 5 is a schematic cross-sectional view showing a general light emitting device. The light emitting device 100 includes a cup-shaped package 110 having an opening at the top, and a light-emitting element 101 mounted in the cup shape of the package 110. Positive and negative lead electrodes 111 are formed on the surface of the package 110. The light emitting element is placed on one electrode of the lead electrode 111, and is electrically connected to the other electrode via the conductive wire 104. Further, the cup of the package 110 is filled with a sealing resin 103 containing a phosphor 102, and the light emitting element 101 is sealed with the sealing resin 103.

  The light emitting element 101 emits light upon receiving power supply from the outside via the lead electrode 111. A part of the light emitted from the light emitting element 101 is converted by the phosphor 102 while passing through the sealing resin 103, and mixed color light is emitted from the upper part of the sealing resin 103. In addition, the light emitting device 100 can reflect the light emitted from the light emitting element 101 to the light extraction side with the reflection member 112, and can improve the light extraction efficiency. The reflecting member 112 is generally made of metal, and is provided so as to cover the lead electrode 111 with, for example, silver, gold, or aluminum having high reflectivity. Hereinafter, each member of the light emitting device will be described.

(Light emitting element)
As the light-emitting element, one that emits light in a short wavelength region from near ultraviolet to visible light can be used. Preferably, it has an emission peak wavelength at 290 to 410 nm. This is because the phosphor according to the present invention can be excited efficiently and visible light can be effectively utilized. In addition, by using a light emitting element as an excitation light source, a stable light emitting device with high efficiency, high output linearity with respect to input, and strong mechanical shock can be obtained.
(Combination of multiple phosphors)
Although the above-mentioned phosphor according to the present invention can be used alone, it can also be used in combination with other phosphors. In particular, the phosphor according to the embodiment of the present invention is difficult to absorb light of other hues adjacent to the hue of the emission peak wavelength, that is, it is difficult to affect the phosphor emitting light in other hues. Therefore, it can be suitably used for a light emitting device that emits mixed color light. A phosphor that hardly interferes with other phosphors can increase the conversion efficiency by excitation and emit light having a wavelength of an intended hue with high luminance. Therefore, in the case of a light emitting device containing a plurality of phosphors, it is preferable that at least one phosphor is the phosphor of the present invention. In this case, the other phosphors absorb light from the light emitting element and can be converted into light having a wavelength different from that of the light emitting element and the one phosphor.

  In addition, it is preferable that the plurality of phosphors mounted on the light-emitting device be formed using the phosphors described in the embodiment and the modified example of the embodiment. That is, it is possible to obtain a light emitting device that contains phosphors having the same composition of the host crystal and the yellow and green light emission hues, respectively. In this light emitting device, the specific gravity of each phosphor can be made substantially the same, so that each phosphor contained in the sealing resin can be diffused substantially uniformly. Since the phosphors arranged substantially uniformly can reduce the uneven distribution of light of each hue, the ratio of color mixture can be made uniform and the directivity of light emission can be reduced. That is, a light emitting device in which color unevenness is prevented is preferable. In addition, as described above, by including a plurality of phosphors that do not easily interfere with each other, secondary absorption of fluorescence in the phosphors can be avoided, and a reduction in luminance can be prevented.

Further, the phosphor contained in the light emitting device is not limited to the above, and various materials can be employed instead of the above phosphor or in addition to the above phosphor. For example, nitride phosphors / oxynitride phosphors / sialon phosphors mainly activated by lanthanoid elements such as Eu and Ce, lanthanoid elements such as Eu, and transition metal elements such as Mn. Activated alkaline earth metal halogen apatite phosphor, alkaline earth metal borate halogen phosphor, alkaline earth metal aluminate phosphor, alkaline earth metal silicate, alkaline earth metal sulfide, alkaline earth Activated mainly by lanthanoid elements such as rare earth aluminates, rare earth silicates or Eu mainly activated by lanthanoid elements such as metal thiogallate, alkaline earth metal silicon nitride, germanate, or Ce It is preferably at least one selected from the group consisting of organic and organic complexes. For example, (Y, Gd, Tb) ₃ (Ga, Al) ₅ O ₁₂ : Ce, (Ca, Sr) ₂ Si ₅ N ₈ : Eu, (Ca, Sr) AlSiN ₃ : Eu, (Ca, Sr, Ba ) Si ₂ O ₂ N ₂ : Eu and the like are listed. By mounting various phosphors, light emitting devices with various colors can be provided. Further, in the embodiment in which the phosphor is mounted on the device, the two or more kinds of phosphors may be mixed and used, or may be arranged as separate layers.
(Examples 19 and 20)

Next, Examples 19 and 20 in which light emitting devices were actually created will be described. In Examples 19 and 20, the yellow-emitting chlorosilicate phosphor according to Example 12 is combined with a blue-emitting phosphor and an LED element. Details of Examples 19 and 20 are shown in Table 4. As shown in this table, Example 19 uses Ca ₅ (PO ₄ ) ₃ (Cl, Br): Eu as the blue light-emitting phosphor, and Example 20 uses BaMgAl ₁₀ O ₁₇ : Eu as the BAM phosphor. doing. The LED element is a surface-mount type (SMD) element of a ceramic package, and emits near-ultraviolet light having a die size of 320 μm × 320 μm and a peak wavelength of 405 nm. A light-emitting device was configured using this element, and after applying a phosphor, it was sealed with a silicone resin. In addition, an emission spectrum of the light-emitting device obtained as a result is shown in FIG. As shown in this table and graph, a light emitting device having excellent color rendering properties could be obtained.

  The light-emitting device obtained as described above was able to obtain a high-quality light-emitting output with little color variation compared to a conventional light-emitting device combining a blue light-emitting LED having a peak wavelength of about 460 nm and a YAG phosphor. In particular, in the conventional light emitting device, the peak value of blue light varies depending on the LED element, and the transmission ratio of the blue light varies depending on the film thickness of the phosphor layer coated on the LED element by potting or the like. In addition, when the film thickness is not uniform over the entire surface or even around the LED element, the film thickness is non-uniform, and the degree of wavelength conversion also fluctuates due to such non-uniformity of the phosphor, resulting in a spectrum of white light. There has been a problem in that unevenness in color occurs in which the light varies from element to element and the output light becomes non-uniform depending on the part.

  In contrast, in the present embodiment, since the light from the LED is not visible light, stable output light can be obtained without being affected by such variations in transmitted light. Reliability can be improved because the output light does not depend on the thickness of the phosphor layer.

  Furthermore, the color temperature of the output light was able to obtain white light in the range of 3000K to 5800K.

  As described above, by adding the rare earth oxide to the chlorosilicate phosphor, a yellow light-emitting phosphor having excellent characteristics could be obtained. The reason for this is unknown whether the rare earth oxide worked as a co-activator or whether it functions as a flux, but it was confirmed that it was effective in improving temperature characteristics and brightness. As a result, a practical yellow light-emitting phosphor can be realized, so that variations in output light caused by non-uniformity of the phosphor layer when a light-emitting device combined with an excitation light source such as an LED chip is suppressed, resulting in improved yield. In addition, high-quality lighting can be obtained.

  The phosphor of the present invention, the light-emitting device using the same, and the method for producing the phosphor use a fluorescent display tube, display, PDP, CRT, FL, FED, projection tube, etc., particularly a blue light-emitting diode or an ultraviolet light-emitting diode as a light source. It can be suitably used for a white illumination light source, an LED display, a backlight light source, a traffic light, an illumination switch, various sensors, various indicators, and the like that have extremely excellent light emission characteristics. In particular, since highly reliable phosphors with little uneven emission are obtained, the industrial utility value is extremely high.

DESCRIPTION OF SYMBOLS 100 ... Light-emitting device 101 ... Light-emitting element 102 ... Phosphor 103 ... Sealing resin 104 ... Conductive wire 110 ... Package 111 ... Lead electrode 112 ... Reflective member

Claims (9)

Phosphor, wherein a set formed is represented by the following general formula.
_{Ca x1 Sr x2 Re y Eu z} Si 6 O a Cl b
(In the above formula, Re is at least one selected from the group consisting of Sc, Y, La, Ce, Pr, Gd, Tb, Dy, Ho, Tm, and Lu;
2 ≦ x1 ≦ 3
3 ≦ x2 ≦ 4
5.0 ≦ x1 + x2 ≦ 7.0,
0 <y <0.05 ,
0 <z ≦ 1.5,
a = (x1 + x2) + (3/2) y + z + 12− (1/2) b,
1.0 ≦ b ≦ 2.0. )   2. The phosphor according to claim 1, wherein a part of the Ca and Sr is substituted with one or more elements selected from the group consisting of Mg, Ba, Zn, and Mn. The phosphor according to claim 1 or 2,
Excited by light having a peak wavelength of 350 nm to 420 nm,
A phosphor having a peak wavelength of an emission spectrum in a wavelength range of 540 to 600 nm. The phosphor according to any one of claims 1 to 3,
A phosphor having a luminance of 56% or more when heated to 200 ° C., based on the luminance of the phosphor at room temperature. An excitation light source that emits light on the short wavelength side of visible light from the near ultraviolet region;
The first phosphor according to any one of claims 1 to 4,
One or more second phosphors that absorb at least part of the light from the excitation light source and emit fluorescence having a peak wavelength of 420 nm to 480 nm;
A translucent resin containing the first and second phosphors;
A light emitting device characterized by using the above. The light-emitting device according to claim 5,
The second phosphor has a larger central particle size than the first phosphor,
The second phosphor is distributed near the excitation light source in the translucent resin to form a color conversion layer, and the first phosphor is distributed outside the color conversion layer in the translucent resin. A light emitting device characterized by comprising: The light-emitting device according to claim 5 or 6,
A light emitting device comprising an apatite phosphor, a BAM phosphor, or a silicate phosphor as the second phosphor. A method for producing a phosphor, comprising:
A step of preparing a simple substance, an oxide, a nitride or a carbonate containing an element contained in the composition represented by the following general formula and pulverizing and / or mixing so as to contain chlorine;
Packing the obtained raw material in a crucible and firing in a reducing atmosphere;
Solid-liquid separation of the fired raw material, drying, pulverization, dispersion, and filtration to obtain the desired phosphor powder;
Including
A method for producing a phosphor, comprising adding an alkaline earth metal chloride as a flux during the firing.
_{Ca x1 Sr x2 Re y Eu z} Si 6 O a Cl b
(In the above formula, Re is at least one selected from the group consisting of Sc, Y, La, Ce, Pr, Gd, Tb, Dy, Ho, Tm, and Lu;
2 ≦ x1 ≦ 3
3 ≦ x2 ≦ 4
5.0 ≦ x1 + x2 ≦ 7.0,
0 <y <0.05 ,
0 <z ≦ 1.5,
a = (x1 + x2) + (3/2) y + z + 12− (1/2) b,
1.0 ≦ b ≦ 2.0. ) It is a manufacturing method of the fluorescent substance according to claim 8,
The method for producing a phosphor, wherein the alkaline earth metal chloride is SrCl ₂ .