JP4834312B2 - Method for manufacturing phosphor for display device and method for manufacturing display device - Google Patents

Description

  The present invention relates to a method for manufacturing a phosphor for a display device and a method for manufacturing a display device using the same.

  In recent years, as a large display device such as a road sign, a display device in which a coating material containing a phosphor is applied in a predetermined shape and irradiated with ultraviolet rays from a fluorescent lamp is widely used. It is coming. As a light source of such a display device, a fluorescent lamp that emits ultraviolet light having a long wavelength such as black light is used.

That is, when ultraviolet rays are used as a light source, ultraviolet rays having a wavelength of 300 nm or less harmful to the eyes are avoided, and ultraviolet rays having a long wavelength of around 330 to 380 nm are used. Specifically, fluorescent lamps using BaSi ₂ O ₅ : Pb phosphor (peak wavelength: 353 nm) and SrB ₄ O ₇ : Eu phosphor (peak wavelength: 370 nm) are used. FIG. 3 shows the emission spectrum distribution of these phosphors.

  Also in LED lamps using light emitting diodes (LEDs), blue, green and red light emitting phosphors are applied to the surface of the LED chip, or phosphor powders of each color light emission are included in the resin constituting the LED. Therefore, it has been attempted to take out light emission of white or any intermediate color from one LED lamp. In such an LED lamp, the phosphor is excited by ultraviolet light having a long wavelength of about 370 nm emitted from the LED.

  For this reason, phosphors for display devices are required to emit visible light efficiently with long-wavelength ultraviolet light (around 330 to 380 nm). In addition, since display devices such as road signs are used outdoors, the phosphors used in such display devices are required to be chemically stable, such as excellent weather resistance.

  However, the red light-emitting phosphor has a problem that it is weakly absorbed with respect to excitation light (ultraviolet light) having a wavelength of about 330 to 380 nm, compared with other light-emitting color phosphors such as blue and green. It is desired to increase the wavelength of the excitation spectrum.

  In recent years, the color sense has been enriched, and various display devices have been required to have subtle hues (color reproduction). From this point of view, the luminous efficiency of long-wavelength ultraviolet light emitted from red phosphors has been increased. Is desired. Furthermore, when the above-mentioned phosphor display device is used for a traffic sign, it is desired to further improve nighttime discrimination, and from this point of view, the long wavelength of the phosphor including the red light emitting phosphor It is desired to increase the luminous efficiency of ultraviolet rays.

  The present invention has been made to cope with such a problem. By increasing the light emission efficiency of long-wavelength ultraviolet light of a phosphor, particularly the light emission efficiency of long-wavelength ultraviolet light of a red light-emitting phosphor, an arbitrary color temperature can be obtained. Provided are a method for manufacturing a phosphor for a display device that can efficiently and accurately extract white light and various intermediate color lights, and a method for manufacturing a display device to which such a method for manufacturing a phosphor for a display device is applied. The purpose is that.

The method for producing a phosphor for a display device according to the present invention is a method for producing a phosphor for a display device containing a blue light emitting component, a green light emitting component, and a red light emitting component.
General _{formula: (La 1-xy Eu x} Sm y) 2 O 2 S
(Wherein x and y are numbers satisfying 0.01 ≦ x ≦ 0.15 and 0.0001 ≦ y ≦ 0.03)
The trivalent europium and samarium activated lanthanum oxysulfide phosphors substantially represented by the formula (1) are used.

  The display device manufacturing method of the present invention is a display device manufacturing method including a light emitting unit including a phosphor and a light source that irradiates light to the light emitting unit, and the phosphor of the light emitting unit is used for the display device described above. The method is characterized by comprising a step of applying a phosphor manufacturing method.

  In the method for producing a phosphor for a display device of the present invention, a trivalent compound that efficiently absorbs long-wavelength ultraviolet light having a wavelength of, for example, around 330 to 380 nm as a red light-emitting component and is excellent in light-emitting characteristics with respect to such long-wavelength ultraviolet light. Phosphors for display devices that can produce white light of various color temperatures and various intermediate color lights efficiently and accurately when excited by long-wavelength ultraviolet light because of the use of the europium and samarium activated lanthanum oxysulfide phosphors Can be provided. Further, by applying such a method for manufacturing a phosphor for a display device, it is possible to improve the light emission efficiency and the like of the display device using long-wavelength ultraviolet light as an excitation source.

Hereinafter, modes for carrying out the present invention will be described. In the method for manufacturing a phosphor for a display device according to an embodiment of the present invention, the phosphor for a display device contains a blue light emitting component, a green light emitting component, and a red light emitting component. Of these luminescent components,
General _{formula: (La 1-xy-z} Eu x Sm y A z) 2 O 2 S ... (1)
(In the formula, A is at least one of Y and Ga, and x and y are numbers satisfying 0.01 ≦ x ≦ 0.15, 0.0001 ≦ y ≦ 0.03, and 0 <z ≦ 0.3)
A trivalent europium and samarium activated lanthanide oxysulfide phosphor substantially represented by the formula (1) is used as a red light emitting component.

  Here, trivalent europium (Eu) is an activator for enhancing the light emission efficiency of lanthanum oxysulfide as a phosphor matrix, and is contained in the range of 0.01 to 0.15 as the value of x in the above formula (1). When the value of x indicating the Eu content is less than 0.01, the effect of improving the light emission efficiency is small, and sufficient luminance cannot be obtained. On the other hand, when the value of x exceeds 0.15, the luminance is significantly lowered due to concentration quenching or the like. More preferably, the value of x is in the range of 0.03 to 0.08.

  In addition to functioning as an activator, samarium (Sm) has an effect of shifting the shape of the excitation spectrum of a phosphor based on lanthanum oxysulfide to the longer wavelength side. As a result, for example, the absorption efficiency of ultraviolet light having a long wavelength of about 330 to 380 nm is improved, and the light emission efficiency at that time can be improved. Sm is contained in the range of 0.0001 to 0.03 as the value of y in the above formula (1). If the value of y indicating the Sm content is less than 0.0001, the effect of shifting the excitation spectrum wavelength to the long wavelength side cannot be sufficiently obtained. On the other hand, when the value of y exceeds 0.03, coloring tends to occur, and the luminance is significantly reduced due to concentration quenching or the like. The value of y is more preferably in the range of 0.001 to 0.01.

In the lanthanum oxysulfide as the phosphor matrix, a part of the lanthanum (La) is at least one element selected from yttrium (Y) and gadolinium (Gd), specifically any one of Y, Gd, and Y + Gd. Replace with Y and Gd exhibit the effect of increasing the emission energy in the red region by being dissolved in the phosphor. However, if the amount of substitution of La by Y or Gd is too large, crystal distortion cannot be ignored, and conversely, the emission intensity decreases. Therefore, the amount of substitution by Y or Gd is preferably 30 mol% or less of La. . A more preferable substitution amount is in the range of 5 to 20 mol%.

  Such trivalent europium and samarium activated lanthanum oxysulfide phosphors as red light-emitting components efficiently absorb long-wavelength ultraviolet light having a wavelength of about 330 to 380 nm. Therefore, red light can be efficiently obtained when excited with such a long wavelength ultraviolet ray.

The trivalent europium and samarium activated lanthanum oxysulfide phosphors are produced, for example, as follows. That is, the first _{La 2 O 3, Eu 2 O} 3, Sm 2 O 3, each raw material powder S and the like, the above-mentioned (1) were weighed predetermined amounts so as to have the composition of formula, Ya These Na ₂ CO ₃ Mix well with a flux such as Li ₃ PO ₄ using a ball mill or the like. The raw material mixture thus obtained is housed in an alumina crucible or the like and fired in the atmosphere at a temperature of about 1100 to 1400 ° C. for about 3 to 6 hours.

  Thereafter, the fired product obtained is washed with pure water to remove unnecessary soluble components. Further, for example, after washing with an acidic solution having a pH of 2 or more, washing with pure water about 3 to 5 times, filtering and drying, the desired red light-emitting phosphor can be obtained. Here, during acid cleaning, by maintaining the pH of the cleaning liquid at 2 or more, non-luminescent components mixed in the phosphor particles can be efficiently removed. More preferably, the pH of the cleaning solution during acid cleaning is kept in the range of 2-4.

  In the method for manufacturing a phosphor for a display device according to this embodiment, a blue light-emitting component and a green light-emitting component are mixed with a red light-emitting component composed of the above-described trivalent europium and samarium-activated lanthanum oxysulfide phosphor. A phosphor is prepared. Here, the phosphor as the blue and green light-emitting components is not particularly limited, but it is preferable to use a phosphor that is excellent in light emission efficiency by long-wavelength ultraviolet rays.

For example, as a blue light emitting component,
General formula: (M1, Eu) ₁₀ (PO ₄ ) ₆ · Cl ₂ (2)
(Wherein M1 represents at least one element selected from Mg, Ca, Sr and Ba)
A divalent europium-activated halophosphate phosphor substantially represented by
General formula: a (M2, Eu) O.bAl ₂ O ₃ (3)
(Wherein M2 represents at least one element selected from Mg, Ca, Sr, Ba, Zn, Li, Rb and Cs, and a and b are a> 0, b> 0, 0.2 ≦ a / b ≦ 1.5)
It is preferable to use a divalent europium activated aluminate phosphor substantially represented by

Moreover, as a green light emission component,
General formula: a (M2, Eu, Mn ) O · bAl 2 O 3 ... (4)
(Wherein M2 represents at least one element selected from Mg, Ca, Sr, Ba, Zn, Li, Rb and Cs, and a and b are a> 0, b> 0, 0.2 ≦ a / b ≦ 1.5)
It is preferable to use a divalent europium and manganese activated aluminate phosphor substantially represented by

  Both the blue light-emitting phosphor and the green light-emitting phosphor described above are excellent in absorption efficiency of long-wavelength ultraviolet light having a wavelength of about 330 to 380 nm. Therefore, when excited with long-wavelength ultraviolet light, blue light and green light Light can be obtained efficiently.

  The mixing ratio of the blue, green, and red light emitting components can be appropriately set according to the target light emission color. For example, when obtaining white light, it is preferable that the blue light-emitting component is 65% or less, the green light-emitting component is in the range of 5 to 65%, and the red light-emitting component is in the range of 15 to 95%. According to such a mixing ratio, for example, white light having a color temperature of about 2700 K to about 8000 K can be arbitrarily obtained, and furthermore, brightness comparable to that of a conventional three-wavelength phosphor excited at a wavelength of 254 nm can be obtained. . The ratio of each color component is more preferably 50% or less for the blue light emitting component, 15 to 45% for the green light emitting component, and 30 to 80% for the red light emitting component.

  Thus, according to the method for manufacturing a phosphor for a display device according to an embodiment of the present invention, long-wavelength ultraviolet light having a wavelength of about 330 to 380 nm is efficiently absorbed as a red light-emitting component, and such long-wavelength ultraviolet light is used. By using trivalent europium and samarium activated lanthanum oxysulfide phosphors with excellent light emission characteristics for the long-wavelength ultraviolet absorption efficiency of the phosphors for display devices containing blue and green light emitting components, blue, green, The luminous efficiency of visible light of each red color can be increased. Therefore, such a phosphor for a display device can efficiently extract white light of an arbitrary color temperature and intermediate color light such as purple, pink, and blue-green by appropriately selecting a combination of each color component. Furthermore, the color reproducibility of each color can be greatly improved.

  The phosphor for a display device to which the manufacturing method of the above-described embodiment is applied has excellent luminous efficiency with respect to ultraviolet rays having a long wavelength of about 330 to 380 nm. Therefore, a phosphor for a display device to which the manufacturing method of the present invention is applied is suitable as a phosphor used in a display device having a light source that emits ultraviolet light having a long wavelength.

  A manufacturing method of a display device according to an embodiment of the present invention manufactures a display device configured to irradiate a light emitting unit including a phosphor with a long wavelength ultraviolet ray or the like from a light source, thereby obtaining visible light from the light emitting unit. In doing so, the method includes the step of producing the phosphor of the light emitting unit by applying the method for producing the phosphor for display device of the above-described embodiment.

  Specifically, a sign display device comprising a light emitting part in which the phosphor for display device of the present invention is applied together with a paint, and a light source (fluorescent lamp or the like) for irradiating the light emitting part with ultraviolet rays, particularly long-wavelength ultraviolet rays. Applicable to manufacturing. In addition, for the manufacture of LED lamps and the like in which the resin layer as the light emitting part containing the phosphor for display device of the present invention is disposed on the outer peripheral side of the light emitting chip that irradiates the light emitting part with light such as ultraviolet light having a long wavelength. Applicable. In such an LED lamp, the phosphor is excited by ultraviolet light having a long wavelength of about 370 nm emitted from the LED.

  Next, specific examples of the present invention and evaluation results thereof will be described.

Example 1, Comparative Examples 1-2
First, a red light emitting phosphor represented by La ₂ O ₂ S: Eu _0.06 , Sm _0.002 and a blue light emitting phosphor represented by (Sr _0.73 Ba _0.22 Ca _0.05 ) ₁₀ (PO ₄ ) ₆ · Cl ₂ : Eu And a green light emitting phosphor represented by 3 (Ba, Mg) O.8Al ₂ O3: Eu _0.20 and Mn _0.40 was prepared. These phosphors of each color emission are weighed so that the red light emission component is 60.5%, the blue light emission component is 18.0%, and the green light emission component is 21.5% by mass ratio. A phosphor for a display device was obtained. The phosphor (mixed phosphor) thus obtained was measured for the emission spectrum distribution when excited with ultraviolet light having a wavelength of 380 nm. The result is shown in FIG.

On the other hand, as Comparative Example 1 with the present invention, a known three-wavelength phosphor [red light-emitting phosphor = Y ₂ O ₃ : Eu / 34.0%, blue light-emitting phosphor = (Sr, Ba, Ca) ₁₀ (PO ₄ ) FIG. 2 shows the emission spectrum distribution when ₆ · Cl ₂ : Eu / 36.0%, green light emitting phosphor = (La, Ce) (P, B) O ₄ : Tb / 30.0%] is excited with ultraviolet light having a wavelength of 254 nm. Shown in The color temperature of the white light emitted from each of these mixed phosphors is about 5000K.

  As a result of obtaining the respective areas from the spectral distributions shown in FIG. 1 and FIG. 2 and comparing the emission luminance, assuming that the three-wavelength phosphor of Comparative Example 1 is 100%, the mixed phosphor of Example 1 has a long wavelength ultraviolet ray. It was found that the brightness was 80% despite being excited by the light, and that the brightness was practically satisfactory.

Further, as Comparative Example 2, a red light-emitting phosphor represented by Y ₂ O ₂ S: Eu _0.05 was 80.0%, and (Sr _0.73 Ba _0.22 Ca _0.05 ) ₁₀ (PO ₄ ) ₆ · Cl ₂ : blue represented by Eu. A phosphor (mixed fluorescence) in which a green phosphor expressed by 8.5%, 3 (Ba, Mg) O.8Al ₂ O ₃ : Eu _0.20 and Mn _0.40 is mixed at a ratio (mass ratio) of 11.5%. ) Was measured for the emission spectrum distribution when excited with ultraviolet light having a wavelength of 380 nm. Assuming that the mixed phosphor of Comparative Example 2 is 100%, the brightness of the mixed phosphor of Example 1 is 216%, and the brightness (efficiency) when excited with long-wavelength ultraviolet light is significantly improved. .

  From each measurement result mentioned above, it turns out that the mixed fluorescent substance by Example 1 is very useful as a fluorescent substance for the display apparatus which uses long wavelength ultraviolet rays (around 330-380 nm) as an excitation source.

Example 2
_{La 2 O 2 S: Eu 0.06} , 64.5% of the red light-emitting phosphor represented by _{Sm 0.002, 3 (Ba, Mg} ) O · 8Al 2 O 3: 12.5% blue emitting phosphor represented by Eu _0.20, 3 (Ba, Mg) O.8Al ₂ O ₃ : The green fluorescent material represented by Eu _0.20 and Mn _0.40 is sufficiently mixed at a ratio (mass ratio) of 23.0% to achieve the desired fluorescence for a display device. Got the body. The phosphor (mixed phosphor) thus obtained was measured for the spectral distribution of light emission when excited with ultraviolet light having a wavelength of 380 nm. The emission color was white light with a color temperature of around 5000K.

  The area was obtained from the obtained emission spectrum distribution and compared with the emission spectrum distribution by the phosphor of Comparative Example 1 described above. Assuming that Comparative Example 1 was 100%, the mixed phosphor of Example 2 was 85% despite being excited by ultraviolet light having a long wavelength, and had a brightness that was practically satisfactory. Furthermore, if the mixed phosphor of Comparative Example 2 described above is 100%, the brightness of the mixed phosphor of Example 2 is 232%, and the brightness (efficiency) when excited with long-wavelength ultraviolet light is significantly improved. Was.

  From the measurement results described above, it can be seen that the mixed phosphor according to Example 2 is very useful as a phosphor for a display device using a long wavelength ultraviolet ray (about 330 to 380 nm) as an excitation source.

Example 3 and Comparative Example 3
La ₂ O ₂ S: Eu _0.06 , red emitting phosphor represented by Sm _0.01 , 61.0%, (Sr _0.80 Ba _0.15 Ca _0.05 ) ₁₀ (PO ₄ ) ₆ · Cl ₂ : blue emitting phosphor represented by Eu 22.0%, 2 (Ba, Mg) O.5Al ₂ O ₃ : Eu _0.20 , Mn _0.40 and the green light emitting phosphor represented by Mn _0.40 are sufficiently mixed at a ratio (mass ratio) of 17.0%. A phosphor for a display device was obtained. The phosphor (mixed phosphor) thus obtained was measured for the spectral distribution of light emission when excited with ultraviolet light having a wavelength of 380 nm. The emission color at this time was white light with a color temperature of around 6500K.

On the other hand, as Comparative Example 3 with the present invention, a known three-wavelength phosphor [red-emitting phosphor = Y ₂ O ₃ : Eu / 32.0%, blue-emitting phosphor = (Sr, Ba, Ca) ₁₀ (PO ₄ ) ₆ · Cl ₂ : Eu / 42.0%, green light emitting phosphor = (La, Ce) (P, B) O ₄ : Tb / 26.0%] was excited with ultraviolet light having a wavelength of 254 nm, and the emission spectrum distribution at that time was It was measured.

  As a result of obtaining the respective areas from the spectrum distributions of Example 3 and Comparative Example 3 and comparing the emission luminance, assuming that the three-wavelength phosphor of Comparative Example 3 is 100%, the mixed phosphor of Example 3 is a long wavelength ultraviolet ray. It was 83% despite being excited by the light, and had a brightness that was practically satisfactory. Therefore, it turns out that the mixed fluorescent substance by Example 3 is very useful as a fluorescent substance for display apparatuses which use long wavelength ultraviolet rays (around 330-380 nm) as an excitation source.

It is a figure which shows the emission spectrum distribution at the time of exciting the fluorescent substance for display apparatuses by Example 1 of this invention with the ultraviolet-ray with a wavelength of 380 nm. It is a figure which shows the emission spectrum distribution at the time of exciting the three wavelength fluorescent substance by the comparative example 1 with the ultraviolet-ray with a wavelength of 254 nm. It is a figure which shows the typical light emission spectrum distribution of the fluorescent substance used for a ultraviolet light-emitting lamp.

Claims (7)

In the method for producing a phosphor for a display device that emits visible light by irradiation with long-wavelength ultraviolet light in the wavelength range of 330 to 380 nm, and contains the blue light-emitting component, green light-emitting component, and red light-emitting component of the visible light ,
As the red light emitting component,
General _{formula: (La 1-xy-z} Eu x Sm y A z) 2 O 2 S
(In the formula, A is at least one of Y and Ga, and x and y are numbers satisfying 0.01 ≦ x ≦ 0.15, 0.0001 ≦ y ≦ 0.03, and 0 <z ≦ 0.3)
Preparing a trivalent europium and samarium with Katsusan sulfide lanthanide phosphor substantially represented in,
In the acid washing step of the oxysulfide lanthanide phosphor, after washing the oxysulfide lanthanide phosphor with pure water, a step of holding the pH in the range of 2 to 4 (pH = 2 with the exception),
Mixing the lanthanide oxysulfide phosphor, the phosphor of the blue light emitting component, and the phosphor of the green light emitting component to produce the phosphor for display device;
A method for producing a phosphor for a display device, comprising: In the manufacturing method of the fluorescent substance for display apparatuses of Claim 1,
As the phosphor of the blue light emitting component,
General formula: (M1, Eu) ₁₀ (PO ₄ ) ₆ · Cl ₂
(Wherein M1 represents at least one element selected from Mg, Ca, Sr and Ba)
And a divalent europium-activated halophosphate phosphor substantially represented by the general formula: a (M ₂ , Eu) O.bAl ₂ O ₃
(Wherein M2 represents at least one element selected from Mg, Ca, Sr, Ba, Zn, Li, Rb and Cs, and a and b are a> 0, b> 0, 0.2 ≦ a / b ≦ 1.5)
A method for producing a phosphor for a display device, comprising using at least one selected from divalent europium activated aluminate phosphors substantially represented by: In the manufacturing method of the fluorescent substance for display apparatuses of Claim 1,
As the phosphor of the green light emitting component,
General _{formula: a (M 2, Eu,} Mn) O · bAl 2 O 3
(Wherein M2 represents at least one element selected from Mg, Ca, Sr, Ba, Zn, Li, Rb and Cs, and a and b are a> 0, b> 0, 0.2 ≦ a / b ≦ 1.5)
A method for producing a phosphor for a display device, comprising using a divalent europium and manganese activated aluminate phosphor substantially represented by the formula: In the manufacturing method of the fluorescent substance for display apparatuses of Claim 1, Claim 2 or Claim 3,
The blue light-emitting component phosphor in a mass ratio of 65% or less, the green light-emitting component phosphor in a range of 5 to 65%, and the red light-emitting component phosphor in a range of 15 to 95%. A method of manufacturing a phosphor for a display device, comprising mixing In a method of manufacturing a display device having a light emitting unit including a phosphor and a light source that irradiates light to the light emitting unit,
The manufacturing method of the display apparatus characterized by comprising the process which produces the said fluorescent substance of the said light emission part by applying the manufacturing method of the fluorescent substance for display apparatuses of Claim 1. In the manufacturing method of the display device according to claim 5 ,
The display device is a sign display device having a fluorescent lamp that irradiates the light emitting unit with ultraviolet rays as the light source. In the manufacturing method of the display device according to claim 5 ,
The display device is an LED lamp having a light emitting chip that irradiates light to the light emitting portion as the light source.

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