JP6241994B2 - Phosphor and method for producing phosphor - Google Patents

Description

  The present invention relates to a novel phosphor and a method for producing the same.

  Conventionally, a method for producing a phosphor that emits light of a target fluorescent color by adding one or more types of coactivators to the main activator is known, among which magnesium silicate and calcium silicate On the other hand, a method for producing a phosphor capable of obtaining light emission of a target color by adding coactivators of various elements has been attempted.

Even in the present inventor, for example, as shown in Patent Document 1 below, Eu ³⁺ (europium) is added as an activator to magnesium silicate in which aluminate is solid-dissolved. A proposal has been made regarding a novel phosphor capable of emitting light in color and a method for producing the same.

JP2013-6920A

  By the way, the inventor of the present application uses such magnesium silicate or calcium silicate as a main activator, adds various activators to this, and fires the raw material to obtain light emission of the target color, thereby producing a novel phosphor. When the firing temperature of calcium silicate as the main activator is too high, the produced phosphor changes from amorphous to crystalline, so-called concentration quenching occurs and the emission intensity decreases I confirmed the phenomenon. On the contrary, it is confirmed that by adjusting the firing temperature and time appropriately, the emission intensity is extremely high at a certain wavelength and a good phosphor can be manufactured, and the proposal according to the present invention is made.

  That is, an object of the present invention is to provide a phosphor capable of emitting light with high intensity in the red range, and a method for producing the same.

Among the phosphors of the present invention, the phosphor according to claim 1 is a phosphor that irradiates excitation light with a wavelength of 980 nm to obtain green light with a wavelength of 546 nm and red light with a wavelength of 659 nm, , Yb ³⁺ , Ho ³⁺ added as an activator and mixed with a calcium chloride mixed aqueous solution to synthesize the phosphor.

Among the phosphors of the present invention, the phosphor according to claim 2 is a phosphor obtained by mixing and synthesizing a calcium chloride mixed aqueous solution to which Ce ³⁺ is further added as an activator.

Among the phosphors of the present invention, the phosphor according to claim 3 is a phosphor obtained by adding Yb ^{3+ so} that the atomic ratio of Yb / Ca is 0.04 to 0.06 and synthesizing the phosphor.

Among the phosphors according to the present invention, the phosphor according to claim 4 is a phosphor formed by adding Ho ^{3+ so} that the atomic ratio of Ho / Ca is 0.0001 to 0.003.

Among the phosphors of the present invention, the phosphor according to claim 5 is a phosphor obtained by adding Ce ^{3+ so} that the Ce / Ca atomic ratio is 0.005 to 0.02 and synthesizing.

Moreover, claim 6 of the present invention is a method for producing a phosphor that irradiates excitation light having a wavelength of 980 nm to obtain green light having a wavelength of 546 nm and red light having a wavelength of 659 nm , wherein Yb ³⁺ A mixing step of mixing a calcium chloride mixed aqueous solution added with Ho ³⁺ as an activator;
A fluorescence comprising: a filtration step of filtering the aqueous solution obtained in the mixing step to obtain a hydrate; and a firing step of firing the hydrate obtained in the filtration step to obtain a phosphor. It is a manufacturing method of a body.

Among the phosphor manufacturing methods of the present invention, the one according to claim 7 is a phosphor manufacturing method in which Ce ³⁺ is further added as an activator and a calcium chloride mixed aqueous solution is mixed in the mixing step. .

Among the methods for producing the phosphor of the present invention, the method according to claim 8 synthesizes the phosphor by adding Yb ^{3+ so} that the atomic ratio of Yb / Ca is 0.04 to 0.06. It is a manufacturing method of fluorescent substance.

Among the phosphor manufacturing methods of the present invention, the phosphor according to claim 9 synthesizes the phosphor by adding Ho ^{3+ so} that the atomic ratio of Ho / Ca is 0.0001 to 0.003. It is a manufacturing method of fluorescent substance.

Among the methods for producing the phosphor of the present invention, the method according to claim 10 synthesizes phosphor by adding Ce ^{3+ so} that the Ce / Ca atomic ratio is 0.005 to 0.02. It is a manufacturing method of fluorescent substance.

  Among the methods for producing a phosphor according to the present invention, a method according to claim 11 is a method for producing a phosphor in which the firing temperature in the firing step is 770 ° C. to 860 ° C.

  Among the phosphor manufacturing methods of the present invention, the phosphor according to claim 12 is a phosphor manufacturing method in which the firing time in the firing step is 15 minutes to 60 minutes.

Among the methods for producing the phosphor of the present invention, a method according to claim 13 is a method for producing a phosphor in which the firing step is performed in the atmosphere or in an Ar—H ₂ atmosphere.

  The present invention can provide a phosphor capable of emitting light with high intensity in the red range.

It is a flowchart which shows the flow of manufacture of the fluorescent substance which concerns on embodiment of this invention. In the Yb ³⁺ Ho ³⁺ co-activated calcium silicate phosphor of Example 1, it is an X-ray diffraction diagram of each phosphor obtained by changing the Ho / Ca atomic ratio. It is a graph which shows the excitation and the emission spectrum of the fluorescent substance shown in FIG. 2 obtained by Ho / Ca atomic ratio change. 4 is a graph showing the influence of a change in Ho / Ca atomic ratio on the emission intensity in the phosphor of Example 1. In the Yb ³⁺ Ho ³⁺ co-activated calcium silicate phosphor of Example 2, it is an X-ray diffraction diagram of each phosphor obtained by changing the Yb / Ca atomic ratio. It is a graph which shows the excitation and the emission spectrum of the fluorescent substance shown in FIG. 5 obtained by Yb / Ca atomic ratio change. It is a graph which shows the influence of the Yb / Ca atomic ratio change which acts on the emitted light intensity in the fluorescent substance of Example 2. 4 is an X-ray diffraction diagram of each phosphor obtained by changing the Ce / Ca atomic ratio in the Ho ³⁺ Ce ³⁺ co-activated calcium silicate phosphor of Example 3. FIG. It is a graph which shows the excitation and the emission spectrum of the fluorescent substance shown in FIG. 8 obtained by Ce / Ca atomic ratio change. It is a graph which shows the influence of Ce / Ca atomic ratio change which acts on the emitted light intensity in the fluorescent substance of Example 3. In the Ho ³⁺ Ce ³⁺ co-activated calcium silicate phosphor of Example 4, it is an X-ray diffraction diagram of each phosphor obtained by changing the firing temperature. It is a graph which shows the excitation and the emission spectrum of the fluorescent substance shown in FIG. 11 obtained by the calcination temperature change. It is a graph which shows the influence of the calcination temperature change which acts on the emitted light intensity in the fluorescent substance of Example 4. In the Yb ³⁺ Ho ³⁺ Ce ³⁺ co-activated calcium silicate phosphor of Example 5, it is an X-ray diffraction diagram of each phosphor obtained by changing the firing time. It is a graph which shows the excitation and the emission spectrum of the fluorescent substance shown in FIG. 14 obtained by baking time change. It is a graph which shows the influence of the baking time change which acts on the emitted light intensity in the fluorescent substance of Example 5.

  FIG. 1 is a flowchart showing a flow of manufacturing a phosphor according to an embodiment of the present invention. The phosphor according to the embodiment of the present invention is synthesized by sequentially executing a mixing step, a filtration step, and a firing step.

In the mixing step, a calcium chloride mixed aqueous solution in which Yb ³⁺ , Ho ³⁺ and Ce ³⁺ are added as activators is mixed with the sodium metasilicate aqueous solution.
The aqueous sodium metasilicate solution is prepared by melting silicon dioxide with sodium carbonate or sodium hydroxide. The production is performed, for example, by stirring for 0.5 hour (step S1 in FIG. 1).
The calcium chloride mixed aqueous solution is prepared by adding an activator to the calcium chloride aqueous solution and then stirring, for example, for 0.5 hour (step S2). In the calcium chloride mixed aqueous solution, Yb ³⁺ is added so that the atomic ratio of Yb / Ca is 0.04 to 0.06, and Ho ³⁺ is the atomic ratio of Ho / Ca is 0.0001 to 0.003. Ce ³⁺ is added so that the Ce / Ca atomic ratio is 0.005 to 0.02.
The mixing of the sodium metasilicate aqueous solution and the calcium chloride mixed aqueous solution is performed, for example, by stirring at room temperature for 0.5 hour (step S3). The sodium metasilicate aqueous solution and calcium chloride mixed aqueous solution are mixed in such an amount that the atomic ratio of (Yb ³⁺ + Ho ³⁺ + Ce ³⁺ + Ca ³⁺ ) / Si is 1.0.

In the filtration step, Yb ³⁺ , Ho ³⁺ , Ce ³⁺ co-activated calcium silicate hydrate is obtained by filtering the aqueous solution obtained in the mixing step (steps S4 and S5).
In the firing step, the hydrate obtained in the filtration step is fired to obtain a phosphor (steps S6 and S7). The firing is preferably performed in an Ar—H ₂ atmosphere at a firing temperature of 770 ° C. to 860 ° C., a firing time of 15 minutes to 60 minutes. Baking may be performed in the air.

Examples of the above embodiment will be described below.
Example 1
2 is an X-ray diffraction pattern of each phosphor obtained by changing the Ho / Ca atomic ratio in the Yb ³⁺ Ho ³⁺ co-activated calcium silicate phosphor of Example 1. FIG. FIG. 3 is a graph showing an excitation / emission spectrum of the phosphor shown in FIG. 2 obtained by changing the Ho / Ca atomic ratio. FIG. 4 is a graph showing the influence of a change in the Ho / Ca atomic ratio on the emission intensity in the phosphor of Example 1. The vertical axis in FIGS. 3 and 4 is an arbitrary unit.

In Example 1, phosphors were synthesized under the following conditions in each step shown in FIG.
(1) Mixing process:
Ytterbium chloride was added as an activator to the calcium chloride aqueous solution so that the atomic ratio Yb / Ca was 0.05. Further, holmium chloride was added as an activator to the calcium chloride aqueous solution. Seven samples having atomic ratios Ho / Ca of 0.0001, 0.0003, 0.0004, 0.0005, 0.0007, 0.001, and 0.003 were prepared depending on the amount of holmium chloride added.
(2) In the filtration step, β-wollastonite was obtained as Yb ³⁺ , Ho ³⁺ co-activated calcium silicate hydrate.
(3) Firing step: Firing was performed under the following conditions.
Firing atmosphere (heating atmosphere): Air (air)
Firing temperature (heating temperature): 830 ° C
Firing time: 0.5 hours

In the measurement of the spectrum, the phosphor was irradiated with excitation light having an excitation wavelength of λex = 980 nm, and the slit width (band width) of the spectrometer was set to 5 nm.
As a result, as shown in FIG. 3, red light having a wavelength of 659 nm was observed in addition to green light having a wavelength of 546 nm. The red light has an emission intensity much higher than that of green light. As shown in FIG. 4, red light having a wavelength of 659 nm has particularly high emission intensity when the atomic ratio Ho / Ca is 0.0003, 0.0004, 0.0005, 0.0007, and 0.001. 0005 is the peak of emission intensity.

(Example 2)
FIG. 5 is an X-ray diffraction diagram of each phosphor obtained by changing the Yb / Ca atomic ratio in the Yb ³⁺ Ho ³⁺ co-activated calcium silicate phosphor of Example 2. FIG. 6 is a graph showing the excitation / emission spectrum of the phosphor shown in FIG. 5 obtained by changing the Yb / Ca atomic ratio. FIG. 7 is a graph showing the influence of the change in the Yb / Ca atomic ratio on the emission intensity in the phosphor of Example 2. The vertical axis in FIGS. 6 and 7 is an arbitrary unit.

Also in Example 2, phosphors were synthesized under the following conditions in each step shown in FIG.
(1) Mixing process:
Holmium chloride was added as an activator to the calcium chloride aqueous solution so that the atomic ratio Ho / Ca was 0.0005. Further, ytterbium chloride was added as an activator to the calcium chloride aqueous solution. Three samples having atomic ratios Yb / Ca of 0.04, 0.05, and 0.06 were prepared depending on the amount of ytterbium chloride added.
(2) In the filtration step, β-wollastonite was obtained as Yb ³⁺ , Ho ³⁺ co-activated calcium silicate hydrate.
(3) Firing step: Firing was performed under the following conditions.
Firing atmosphere (heating atmosphere): Air (air)
Firing temperature (heating temperature): 830 ° C
Firing time: 0.5 hours

In the measurement of the spectrum, the phosphor was irradiated with excitation light having an excitation wavelength of λex = 980 nm, and the slit width (band width) of the spectrometer was set to 5 nm.
As a result, as shown in FIG. 6, red light having a wavelength of 659 nm was observed in addition to green light having a wavelength of 546 nm. The red light has an emission intensity much higher than that of green light. As shown in FIG. 7, the red light having a wavelength of 659 nm has a peak of emission intensity when the atomic ratio Yb / Ca is 0.05.

(Example 3)
FIG. 8 is an X-ray diffraction pattern of each phosphor obtained by changing the Ce / Ca atomic ratio in the Ho ³⁺ Ce ³⁺ co-activated calcium silicate phosphor of Example 3. FIG. 9 is a graph showing the excitation / emission spectrum of the phosphor shown in FIG. 8 obtained by changing the Ce / Ca atomic ratio. FIG. 10 is a graph showing the influence of a change in Ce / Ca atomic ratio on the emission intensity in the phosphor of Example 3. The vertical axis in FIGS. 9 and 10 is an arbitrary unit.

Also in Example 3, phosphors were synthesized under the following conditions in each step shown in FIG.
(1) Mixing process:
Ytterbium chloride and holmium chloride were added as activators to the calcium chloride aqueous solution so that the atomic ratio Yb / Ca was 0.05 and Ho / Ca was 0.0005. Moreover, cerium chloride was added as an activator to the calcium chloride aqueous solution. Four samples with atomic ratios Ce / Ca of 0.005, 0.010, 0.015, and 0.020 were prepared depending on the amount of cerium chloride added.
(2) In the filtration step, β-wollastonite was obtained as Yb ³⁺ , Ho ³⁺ , Ce ³⁺ co-activated calcium silicate hydrate.
(3) Firing step: Firing was performed under the following conditions.
Firing atmosphere (heating atmosphere): Ar—H ₂
Firing temperature (heating temperature): 830 ° C
Firing time: 0.5 hours

In the measurement of the spectrum, the phosphor was irradiated with excitation light having an excitation wavelength of λex = 980 nm, and the slit width (band width) of the spectrometer was set to 2.5 nm.
As a result, as shown in FIG. 9, red light having a wavelength of 659 nm was observed in addition to green light having a wavelength of 546 nm. The red light has an emission intensity much higher than that of green light. As shown in FIG. 10, red light having a wavelength of 659 nm has a peak of emission intensity when the atomic ratio Ce / Ca is 0.010.

Example 4
FIG. 11 is an X-ray diffraction pattern of each phosphor obtained by changing the firing temperature in the Ho ³⁺ Ce ³⁺ co-activated calcium silicate phosphor of Example 4. FIG. 12 is a graph showing the excitation / emission spectrum of the phosphor shown in FIG. 11 obtained by changing the firing temperature. FIG. 13 is a graph showing the influence of the firing temperature change on the emission intensity in the phosphor of Example 4. The vertical axis in FIGS. 12 and 13 is an arbitrary unit.

Also in Example 4, phosphors were synthesized under the following conditions in each step shown in FIG.
(1) Mixing process:
Ytterbium chloride, holmium chloride, and cerium chloride as activators for an aqueous calcium chloride solution so that the atomic ratio Yb / Ca is 0.05, Ho / Ca is 0.0005, and Ce / Ca is 0.01. Was added.
(2) In the filtration step, β-wollastonite was obtained as Yb ³⁺ , Ho ³⁺ , Ce ³⁺ co-activated calcium silicate hydrate.
(3) Firing step: Firing was performed under the following four conditions.
Firing atmosphere (heating atmosphere): Ar—H ₂
Firing temperature (heating temperature): 770 ° C, 800 ° C, 830 ° C, 860 ° C,
Firing time: 0.5 hours

In the measurement of the spectrum, the phosphor was irradiated with excitation light having an excitation wavelength of λex = 980 nm, and the slit width (band width) of the spectrometer was set to 2.5 nm.
As a result, as shown in FIG. 12, red light having a wavelength of 659 nm was observed in addition to green light having a wavelength of 546 nm. The red light has an emission intensity much higher than that of green light. As shown in FIG. 13, red light having a wavelength of 659 nm has a peak of emission intensity when the baking temperature is 830 ° C.

(Example 5)
14 is an X-ray diffraction pattern of each phosphor obtained by changing the firing time in the Yb ³⁺ Ho ³⁺ Ce ³⁺ co-activated calcium silicate phosphor of Example 5. FIG. FIG. 15 is a graph showing an excitation / emission spectrum of the phosphor shown in FIG. 14 obtained by changing the firing time. FIG. 16 is a graph showing the influence of the firing time change on the emission intensity in the phosphor of Example 5. The vertical axis in FIGS. 15 and 16 is an arbitrary unit.

Also in Example 5, phosphors were synthesized under the following conditions in each step shown in FIG.
(1) Mixing process:
Ytterbium chloride, holmium chloride, and cerium chloride as activators for an aqueous calcium chloride solution so that the atomic ratio Yb / Ca is 0.05, Ho / Ca is 0.0005, and Ce / Ca is 0.01. Was added.
(2) In the filtration step, β-wollastonite was obtained as Yb ³⁺ , Ho ³⁺ , Ce ³⁺ co-activated calcium silicate hydrate.
(3) Firing step: Firing was performed under the following three conditions.
Firing atmosphere (heating atmosphere): Ar—H ₂
Firing temperature (heating temperature): 830 ° C
Firing time: 15 minutes, 30 minutes, 60 minutes

In the measurement of the spectrum, the phosphor was irradiated with excitation light having an excitation wavelength of λex = 980 nm, and the slit width (band width) of the spectrometer was set to 2.5 nm.
As a result, as shown in FIG. 15, red light with a wavelength of 659 nm was observed in addition to green light with a wavelength of 546 nm. The red light has an emission intensity much higher than that of green light. As shown in FIG. 16, red light having a wavelength of 659 nm has a peak of emission intensity when the baking time is 30 minutes (0.5 hours).

  The phosphor according to the present invention and the phosphor obtained by the method for producing the same are based on calcium silicate hydrate obtained by mixing a sodium metasilicate aqueous solution and a calcium chloride mixed aqueous solution. Red light can be emitted from a phosphor based on a simple oxide.

Claims (13)

A phosphor to obtain a red light green light and wavelength 659nm wavelength 546nm is irradiated with excitation light having a wavelength of 980 nm, with respect to sodium metasilicate ^solution, Yb 3+, calcium chloride mixture added with ^{Ho 3+} as an activator A phosphor obtained by mixing and synthesizing an aqueous solution. The phosphor according to claim 1, wherein the phosphor is obtained by mixing and synthesizing a calcium chloride mixed aqueous solution to which Ce ³⁺ is further added as an activator. The phosphor according to claim 1, wherein Yb ³⁺ is added and synthesized so that the atomic ratio of Yb / Ca is 0.04 to 0.06. The phosphor according to claim 1, wherein Ho ³⁺ is added and synthesized such that the atomic ratio of Ho / Ca is 0.0001 to 0.003. The phosphor according to claim 2, wherein Ce ³⁺ is added and synthesized such that the Ce / Ca atomic ratio is 0.005 to 0.02. A method for producing a phosphor that irradiates excitation light having a wavelength of 980 nm to obtain green light having a wavelength of 546 nm and red light having a wavelength of 659 nm,
A mixing step of mixing an aqueous solution of calcium chloride mixed with Yb ³⁺ and Ho ³⁺ as an activator to an aqueous solution of sodium metasilicate;
A filtration step of filtering the aqueous solution obtained in the mixing step to obtain a hydrate;
And a firing step of firing the hydrate obtained in the filtration step to obtain a phosphor. The method for producing a phosphor according to claim 6, wherein in the mixing step, Ce ³⁺ is further added as an activator, and a calcium chloride mixed aqueous solution is mixed. The method for producing a phosphor according to claim 6, wherein Yb ³⁺ is added so that an atomic ratio of Yb / Ca is 0.04 to 0.06 to synthesize the phosphor. The method for producing a phosphor according to claim 6, wherein the phosphor is synthesized by adding Ho ^{3+ so} that the atomic ratio of Ho / Ca is 0.0001 to 0.003. The method for producing a phosphor according to claim 7, wherein Ce ³⁺ is added so that the Ce / Ca atomic ratio is 0.005 to 0.02 to synthesize the phosphor.   The method for producing a phosphor according to any one of claims 6 to 10, wherein a firing temperature in the firing step is 770 ° C to 860 ° C.   The method for producing a phosphor according to any one of claims 6 to 11, wherein a firing time in the firing step is 15 minutes to 60 minutes. The firing step method for manufacturing the phosphor according to any one of claims 6 to claim 12, characterized in that in an atmosphere of air or in Ar-H _2.