Patent Application
20230241409
The present disclosure relates to a light irradiation type cosmetic apparatus and an electronic device.
A light irradiation type cosmetic apparatus has been recently known for performing photocosmetic treatment, such as taking care of unwanted hair, removal of spots and freckles, or the like, through irradiation of skin with near-infrared light. For example, irradiation of hair cells with near-infrared light of relatively high intensity is known to be effective for hair removal because proteins associated with melanin pigments are denatured through heat coagulation, thereby reducing the hair regenerative function. It is known that near-infrared light of relatively high intensity is also effective in removing spots and freckles. Thus, when near-infrared light is used at high-output within a range that does not have a harmful influence on the human body, the effect of photocosmetic treatment is likely to be high. LEDs, xenon lamps, and the like are known as a light source of high-output near-infrared light.
Note that when a xenon lamp is used, the output light of the xenon lamp includes light in a wavelength range shorter than that of near-infrared light. Thus, a light irradiation type cosmetic apparatus using a xenon lamp light source is not energy efficient because light in the wavelength range of 550 nm or less is usually cut off by a filter. Then, as a light source or a light emitting device for a light irradiation type cosmetic apparatus, one that can emit a large amount of a light component of near-infrared light is desired. Here, a light emitting device including a phosphor that emits near-infrared light is being considered. Note that the light output of a phosphor generally tends to be saturated when the phosphor is irradiated with high-output light. Thus, a light emitting device capable of outputting high-output near-infrared light is desired. Various conventional light emitting devices have been considered as a light emitting device capable of outputting high-output near-infrared light.
For example, a configuration (P) light emitting device using a Cr3+-activated phosphor is known. Also, a configuration (Q) light emitting device including an LED chip that emits incoherent light and including a near-infrared phosphor is known. Furthermore, a configuration (R) light emitting device including a light source that emits coherent laser light, such as a laser diode, and including a phosphor (hereinafter called a “red phosphor”) that emits a red fluorescent component is known.
Patent Literature 1 discloses a light emitting device using a YAG-based phosphor co-activated with Cr3+ and Ce3+, as a light emitting device satisfying the configurations (P) and (Q). Examples of the above-described YAG-based phosphor used include Y3Al5O12:Cr3+, Ce3+, Lu3Al5O12:Cr3+, Ce3+, Y3(Al, Ga)5O12:Cr3+, Ce3+, and (Y, Gd)3Al5O12:Cr3+, Ce3+.
Patent Literature 2 discloses an illumination light source for plant growth using a phosphor having a fluorescence peak in a wavelength range of 700 to 760 nm corresponding to a light absorption spectrum of pigment proteins (phytochromes) possessed by plants, as a light emitting device satisfying the configurations (P) and (Q). Specifically, Patent Literature 2 discloses a plant-growth illumination light source that packages a blue LED and a Gd3Ga5O12:Cr3+ phosphor having a fluorescence peak in the wavelength range of 700 to 760 nm. With this illumination light source, the wavelength range of 700 to 760 nm where the fluorescent peak of the phosphor exists corresponds to the light absorption spectrum of the pigment protein (phytochromes), and thus it is possible to control the growth and differentiation of plants. Patent Literature 6 discloses an infrared light emitting device that emits light in a wide band in a wavelength range where the light reception sensitivity of an Si photodiode detector is high.
Patent Literature 3 discloses a medical inspection device that outputs a reflected image and a transmission image of a near-infrared light component emitted on living tissue, as a light emitting device satisfying the configuration (Q). This medical inspection device uses, as a near-infrared light component, a fluorescent component emitted by a phosphor containing the rare earths Nd and Yb as activators.
Patent Literature 4 discloses a light device in which various lasers are applied, including a laser diode, and including a red phosphor activated with Ce3+, as a light emitting device satisfying the configuration (R).
Note that the light emitting devices described in Patent Literatures 1 to 3 and 6 that do not satisfy the configuration (R) are for the purpose of providing lighting devices for growing plants, and the like, simply to obtain output light containing a near-infrared light component suitable for growing plants, and the like. That is, the light emitting devices described in Patent Literatures 1 to 3 and 6 do not solve the issue in which the light output of a phosphor is saturated, which is inherent in a light emitting device using high-output light such as laser light. Thus, the light emitting devices described in Patent Literatures 1 to 3 and 6 do not limit, in an extreme manner, the shape and the like of the fluorescence spectrum emitted by the Cr3+-activated phosphor in order to solve the issue in which the light output of the phosphor is saturated.
As a light emitting device using a near-infrared phosphor, a lighting device mainly for plant growth is known. However, this light emitting device is simply for obtaining output light containing a near-infrared light component suitable for growing plants, and does not solve the issue in which the light output of a phosphor is saturated when the phosphor is subjected to high-density photoexcitation.
As a light emitting device using high-output light such as laser light, a light emitting device that obtains visible output light using a phosphor activated mainly with a rare earth ion (Ce3+ or Eu2+) is known. However, this light emitting device does not provide near-infrared high-output light based on a Cr3+ electron energy transition.
As described above, a light emitting device where a phosphor is excited by high-output light such as laser light has had the issue until now in which the fluorescence output of the phosphor is saturated. To suppress the saturation of the fluorescence output, it has been considered essential to use a phosphor having a short afterglow (10 μs or less), which exhibits fluorescence based on a parity-allowed transition, such as Ce3+ or Eu2+, as described in Patent Literatures 4 and 5. In particular, the use of a Ce3+-activated phosphor exhibiting an ultrashort afterglow (10 to 100 ns) was considered to be preferable.
However, in a light emitting device in which a phosphor is excited by laser light, the following issues arise when the near-infrared light component necessary in a light irradiation type cosmetic apparatus is obtained by using a Ce3+-activated phosphor or an Eu2+-activated phosphor. That is, it is difficult to develop a phosphor because the selection of materials used for the phosphor is narrow and the temperature quenching becomes large, and thus a light emitting device that emits a near-infrared light component cannot be obtained.
The present disclosure has been made in consideration of these issues. The present disclosure is achieved by finding that when a phosphor having Cr3+ as an activator and emitting long-afterglow (10 μs or more) fluorescence based on a parity-forbidden transition is used, the saturation of fluorescence output is less likely to occur even under photoexcitation emitted from a solid-state light source having a high-density rated output of 1 W or more, which is contrary to conventional common technical knowledge.
The above-described finding is surprising because it differs greatly from the conventional common technical knowledge that the use of a phosphor having a short afterglow (less than 10 μs) is essential to suppress the saturation of fluorescence output.
An object of the present disclosure is to provide a light irradiation type cosmetic apparatus that emits high-output light having a high proportion of a near-infrared fluorescent component under excitation with high-output light, and an electronic device using the light irradiation type cosmetic apparatus.
In response to the above issues, a light irradiation type cosmetic apparatus according to an aspect of the present disclosure includes a light emitting device including a light source that emits primary light, and a first phosphor that absorbs the primary light and converts the primary light into first wavelength-converted light having a wavelength longer than that of the primary light, wherein the light source is a solid-state light source having a rated output of 1 W or more, the primary light is light emitted from the solid-state light source, the first wavelength-converted light contains fluorescence based on an electron energy transition of Cr3+, and the first wavelength-converted light has a fluorescence spectrum having a fluorescence intensity maximum value in a wavelength range exceeding 710 nm.
An electronic device according to another aspect of the present disclosure includes the light irradiation type cosmetic apparatus.
A light irradiation type cosmetic apparatus according to the present embodiment is described below with reference to the drawings. Note that dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios.
As illustrated in
As illustrated in
(Light Emitting Device (First Light Emitting Device))
As illustrated in
The light source 2 includes multiple solid-state light emitting elements 200. A driving power source 50 is connected to each of the solid-state light emitting elements 200 constituting the light source 2 to supply power to cause the solid-state light emitting elements 200 to emit light. When power is supplied from the driving power source 50 to the solid-state light emitting elements 200 by pressing the power button 41 or the like, the solid-state light emitting elements 200 of the light source 2 emit the primary light 6.
In the light emitting device 1A, the light source 2 and the wavelength converter 3A are arranged in such a manner that the primary light 6 emitted from the solid-state light emitting elements 200 of the light source 2 is emitted on the wavelength converter 3A including the first phosphor 4. The first phosphor 4 included in the wavelength converter 3A absorbs the primary light 6 emitted by the light source 2, converts it into the first wavelength-converted light 7 having a wavelength longer than that of the primary light 6, and emits it through the wavelength converter 3A. Note that part of the primary light 6 emitted from the light source 2 to the wavelength converter 3A usually penetrates or is reflected by the wavelength converter 3A. Thus, when the primary light 6 is emitted from the light source 2 to the wavelength converter 3A, the output light 15 including the primary light 6 and the first wavelength-converted light 7 is emitted from one surface of the wavelength converter 3A opposite to the other surface thereof facing the light source 2, for example.
In the light emitting device 1A illustrated in
The head part 30 has a tubular head part body 31 and the irradiation port 110 arranged at the end of the head part body 31. The head part 30 is attached to the head-side end part 23 of the body part 20. The head part 30 outputs the output light 15 emitted from the light emitting device 1A of the body part 20 to the outside of the light irradiation type cosmetic apparatus 10 through the irradiation port 110. The head part 30 has a known structure in which the output light 15 introduced from the wavelength converter 3A of the body part 20 is emitted from the irradiation port 110.
When the output light 15 is emitted on human skin from the irradiation port 110 of the light irradiation type cosmetic apparatus 10, the output light 15 acts on melanin pigments to decrease a regenerative function of hair, and thus it is possible to obtain a temporary hair growth reduction effect and a hair growth suppression effect. It is also possible to obtain an effect of the removal of spots, freckles, and the like. Specifically, the first wavelength-converted light 7 included in the output light 15 is light that emits fluorescence based on an electron energy transition of Cr3+ and satisfying the following property (A) and contains a light component in a wavelength range suitable for easier absorption by melanin pigments than by blood and the like. Thus, when the output light 15 including the first wavelength-converted light 7 is emitted on human skin, a burn is less likely to occur, thermal efficiency is high, and destruction, coagulation, or the like occurs in melanin pigments and the like. When the melanin pigments and the like, which have been destroyed or coagulated, come to the surface through the skin's metabolism and are then peeled off and removed from the skin, it is expected that beautiful skin can be obtained through the suppression of unwanted hair growth and the removal of spots, freckles, and the like. The fact that the first wavelength-converted light 7 included in the output light 15 is light in a wavelength range suitable for easier absorption by melanin pigments than by blood and the like is described later.
In the light emitting device 1A of the light irradiation type cosmetic apparatus 10, when the primary light 6 emitted from the light source 2 enters the wavelength converter 3, a phosphor, such as the first phosphor 4, included in the wavelength converter 3 emits fluorescence. When receiving the primary light 6, the first phosphor 4 emits the first wavelength-converted light containing fluorescence based on the electron energy transition of Cr3+ and having a fluorescence intensity maximum value in a wavelength range exceeding 710 nm.
The light emitting device 1A of the light irradiation type cosmetic apparatus 10 emits the first wavelength-converted light that contains a greater amount of a broad spectral component having a fluorescence intensity maximum value in a wavelength range exceeding 710 nm, than a linear spectral component having a fluorescence intensity maximum value in a wavelength range of 680 to 710 nm. Thus, the light emitting device 1A is a light emitting device that contains a large amount of the near-infrared component.
Note that the above-described linear spectral component is a long-afterglow light component based on an electron energy transition (spin-forbidden transition) of 2T1 and 2E→4A2 of Cr3+. The above-described broad spectral component is a short-afterglow light component based on an electron energy transition (spin-allowed transition) of 4T2→4A2. The mechanism of fluorescence related to Cr3+ is described below.
The light source 2 and the wavelength converter 3A are described in detail below.
<Light Source>
The light source 2 is a solid-state light source having a rated output of 1 W or more and emits the primary light 6. That is, light emitted from a solid-state light source having a rated output of 1 W or more is used as the primary light 6. As the primary light 6 that is light emitted from a solid-state light source having a rated output of 1 W or more, warm color light having an intensity maximum value within a wavelength range of 600 nm or more and less than 710 nm is used, for example. As the warm color light, light having an intensity maximum value within a wavelength range of 600 nm or more and less than 680 nm is preferably used.
When the warm color light is used as the primary light 6, the primary light 6 is well absorbed by the first phosphor 4 activated with Cr3+ and is efficiently wavelength-converted to the first wavelength-converted light 7. Thus, it is possible for the light emitting device 1A and the light irradiation type cosmetic apparatus 10 including the light emitting device 1A to emit output light having a large proportion of a fluorescent component based on the electron energy transition of Cr3+.
It is preferable to use the warm color light as the primary light 6 because the Stokes shift between the primary light 6 in the first phosphor 4 and the first wavelength-converted light 7 becomes smaller and thus it becomes difficult for the light source 2 to generate heat.
It is preferable to use the warm color light as the primary light 6 because even when the primary light 6 penetrates the wavelength converter 3A and is emitted on human skin, it is less likely to have a harmful influence on human skin.
As the light source 2, for example, a solid-state light source, such as a warm-color laser element or a warm-color LED, emitting the above-described warm color light is used. When the light source 2 is a warm-color laser element or a warm-color LED, a phosphor in the wavelength converter 3 is excited with high efficiency, which enables the light emitting device 1B and the light irradiation type cosmetic apparatus 10 including the light emitting device 1B to emit high-output near-infrared light. Since the light source 2 is a solid-state light source, such as a laser element or an LED, it has excellent durability and a long life.
A red laser element or a red LED in the warm-color laser element or the warm color LED has a small energy difference from a near-infrared light component and a small energy loss due to wavelength conversion. Thus, it is preferable to use a red laser element or a warm color LED as the light source 2 for achieving the high efficiency of the light emitting device 1A and the light irradiation type cosmetic apparatus 10 including the light emitting device 1A.
For example, a surface emitting laser diode or an LED is used as the solid-state light emitting elements 200 constituting the light source 2. The light source 2 has a rated light output of 1 W or more, preferably 3 W or more. When the rated light output of the light source 2 is within the above-described ranges, the light source 2 emits the high-output primary light 6, and thus it is possible to achieve high output of the light emitting device 1A and the light irradiation type cosmetic apparatus 10 including the light emitting device 1A.
Note that there is no particular upper limit for the rated light output. It is possible for the light source 2 to achieve high output by increasing the number of solid-state light emitting elements 200. However, for practicality, the rated light output of the light source 2 is usually less than 10 kW, preferably less than 3 kW.
The power density of the primary light 6 emitted on the first phosphor 4 is usually 0.5 W/mm2 or more, preferably more than 3 W/mm2, more preferably more than 10 W/mm2, even more preferably more than 30 W/mm2. When the power density of the primary light 6 is within the above-described ranges, the first phosphor 4 is excited by high density light, and thus it becomes possible for the light emitting device 1A and the light irradiation type cosmetic apparatus 10 including the light emitting device 1A to emit a high-output fluorescent component.
<Wavelength Converter>
The wavelength converter 3A includes the first phosphor 4 and a sealant 5. In the wavelength converter 3A, the first phosphor 4 is usually included in the sealant 5.
[First Phosphor]
The first phosphor 4 is a phosphor that absorbs the primary light 6 and converts it into the first wavelength-converted light 7 having a wavelength longer than that of the primary light 6. The first phosphor 4 absorbs the primary light 6 and emits the first wavelength-converted light 7 containing fluorescence based on the electron energy transition of Cr3+. That is, the first wavelength-converted light 7 contains fluorescence based on the electron energy transition of Cr3+. Here, the fluorescence based on the electron energy transition of Cr3+ means fluorescence based on the electron energy transition (spin-allowed transition) of 4T2→4A2.
The electron energy transition of Cr3+ is described below.
The horizontal axis in
The vertical axis in
Here, the electron energy transition accompanied by fluorescence usually results in an electron energy transition from the lowest excited state (2T1 and 2E or 4T2 in
Note that in the electron energy transition from 2T1 and 2E to 4A2, as can be seen from
In contrast, in the electron energy transition from 4T2 to 4A2, as can be seen from
Note that the energy transition between energy levels in the 2T1 and 2E to 4A2 electron energy transition of 3d electrons of Cr3+ is a parity-forbidden transition, and thus the fluorescence afterglow time is as long as 100 μs to less than 50 ms. The afterglow time of the fluorescence based on this Cr3+ is longer compared to that of Ce3+ or Eu2+ fluorescence (10 μs or less), which exhibit a parity-allowed transition. However, the electron energy transition from 4T2 to 4A2 of Cr3+ is a spin-allowed transition between two states having the same spin, and thus the afterglow time is relatively short, around 100 μs.
Such a Cr3+-activated phosphor that exhibits fluorescence due to a parity-forbidden (spin-allowed) electron energy transition exhibits a much longer afterglow property than an Eu2+-activated phosphor that exhibits fluorescence due to a parity-allowed electron energy transition. The present disclosure is achieved by finding that the Cr3+-activated phosphor exhibiting fluorescence due to a parity-forbidden electron energy transition has surprisingly little saturation of fluorescence output even though it exhibits a much longer afterglow property than an Eu2+-activated phosphor.
The first phosphor 4 emits fluorescence satisfying the following property (A) because the first wavelength-converted light 7 is fluorescence based on the spin-allowed electron energy transition of Cr3+. The first phosphor 4 preferably emits fluorescence that satisfies at least one of the properties (B) or (C), in addition to the property (A).
[Property A]
The property (A) is that the fluorescence spectrum of the first wavelength-converted light 7 has a fluorescence intensity maximum value in a wavelength range exceeding 710 nm. Here, the fluorescence intensity maximum value means the maximum fluorescence intensity at a peak where the fluorescence intensity exhibits the maximum value between peaks in the fluorescence spectrum. The fluorescence spectrum of the first wavelength-converted light 7 preferably has a fluorescence intensity maximum value in a wavelength range of 710 nm or more and less than 900 nm.
With the light emitting device 1A satisfying the property (A) and the light irradiation type cosmetic apparatus 10 including the light emitting device 1A, in which the fluorescence spectrum of the first wavelength-converted light 7 has a fluorescence intensity maximum value in a wavelength range exceeding 710 nm, it is possible to easily obtain a point light source containing a large amount of the near-infrared component.
The light emitting device 1A satisfying the property (A) is suitable as a light emitting device included in the light irradiation type cosmetic apparatus 10 because the fluorescence spectrum of the first wavelength-converted light 7 has a fluorescence intensity maximum value in a wavelength range exceeding 710 nm, which is a wavelength range suitable for a light irradiation type cosmetic apparatus. The reason why the fluorescence spectrum of the first wavelength-converted light 7 is suitable for a light irradiation type cosmetic apparatus when it has a fluorescence intensity maximum value in a wavelength range exceeding 710 nm is described below.
Oxyhemoglobin is a substance contained in erythrocytes of a human and so on, and the light absorption rate of oxyhemoglobin can be regarded as the light absorption rate of human blood. Melanin is a substance contained in hair, spots, freckles, and the like of a human and so on, and the light absorption rate of melanin can be regarded as the light absorption rate of human hair, spots, and freckles. Water is a substance contained in a body fluid of a human and so on, and the light absorption rate of water can be regarded as the light absorption rate of human blood.
Thus, in
In contrast, in
In
[Property (B)]
The property (B) is that the percentage of a fluorescence intensity at the wavelength of 780 nm with respect to the fluorescence intensity maximum value in the fluorescence spectrum of the first wavelength-converted light 7 exceeds 30%. Hereinafter, the above-described percentage of the fluorescence intensity is also referred to as a “780-nm fluorescence intensity percentage”. The 780-nm fluorescence intensity percentage preferably exceeds 60%, more preferably exceeds 80%.
When the 780-nm fluorescence intensity percentage is within the above-described ranges, the first wavelength-converted light 7 contains a large amount of a fluorescent component in the near-infrared wavelength range (650 to 1000 nm) in which light easily penetrates a living body, which is called a “biological window”. Thus, it is possible for the light irradiation type cosmetic apparatus 10 that emits the first wavelength-converted light 7 satisfying the property (B) to increase the light intensity of near-infrared light penetrating a living body.
[Property C]
The property (C) is that the 1/10 afterglow of the first wavelength-converted light 7 is less than 1 ms. Here, the 1/10 afterglow means a time τ1/10 required from the time exhibiting the maximum emission intensity to the time to reach the 1/10 intensity of the maximum emission intensity. The 1/10 afterglow is preferably 10 μs or more and less than 1 ms, more preferably 10 μs or more and less than 800 μs, further more preferably 10 μs or more and less than 400 μs, particularly preferably 10 μs or more and less than 350 μs, more particularly preferably 10 μs or more and less than 100 μs.
When the 1/10 afterglow falls within the above-described ranges, the output of the fluorescence emitted by the first phosphor 4 is less likely to saturate, even when the power density of excitation light that excites the first phosphor 4 is high. It is thus possible for the light irradiation type cosmetic apparatus 10 that emits the first wavelength-converted light 7 satisfying the property (C) to emit high-output near-infrared light with less saturation of the fluorescence output when high-output density light emitted from a solid-state light source having a rated output of 1 W or more is emitted.
Note that the 1/10 afterglow of the first wavelength-converted light 7 becomes longer than that of short-afterglow (less than 10 μs) fluorescence based on the parity-allowed transition of Ce3+, Eu2+, or the like. This is because the first wavelength-converted light 7 is fluorescence based on the spin-allowed electron energy transition of Cr3+ and having a relatively long afterglow
As the first phosphor 4, it is possible to use phosphors such as Lu2CaMg2(SiO4)3:Cr3+, Y3Ga2(AlO4)3:Cr3+, Y3Ga2(GaO4)3:Cr3+, Gd3Ga2(AlO4)3:Cr3+, Gd3Ga2(GaO4)3:Cr3+, (Y, La)3Ga2(GaO4)3:Cr3+, (Gd, La)3Ga2(GaO4)3:Cr3+, Ca2LuZr2(AlO4)3:Cr3+, Ca2GdZr2(AlO4)3:Cr3+, Lu3Sc2(GaO4)3:Cr3+, Y3Sc2(AlO4)3:Cr3+, Y3Sc2(GaO4)3:Cr3+, Gd3Sc2(GaO4)3:Cr3+, La3Sc2(GaO4)3:Cr3+, Ca3Sc2(SiO4)3:Cr3+, Ca3Sc2(GeO4)3:Cr3+, BeAl2O4:Cr3+, LiAl5O8:Cr3+, LiGa5O8:Cr3+, Mg2SiO4:Cr3+, Li+, La3Ga5GeO14:Cr3+, and La3Ga5.5Nb0.5O14:Cr3+.
The first phosphor 4 is preferably made from ceramic. When the first phosphor 4 is made from ceramic, the heat dissipation of the first phosphor 4 is enhanced, and thus a decrease in the output of the first phosphor 4 due to temperature quenching is suppressed, and it becomes possible for the light irradiation type cosmetic apparatus 10 to emit high-output near-infrared light.
In the light irradiation type cosmetic apparatus 10, the first wavelength-converted light 7 emitted by the first phosphor 4 has a specific fluorescent component based on the electron energy transition of Cr3+.
Note that the fluorescence spectrum of the first wavelength-converted light 7 preferably does not include traces of a linear spectral component derived from the electron energy transition of Cr3+. The linear spectral component derived from the electron energy transition of Cr3+ is a long-afterglow fluorescent component due to the spin-forbidden transition of Cr3+. When the fluorescence spectrum of the first wavelength-converted light 7 does not include the above-described traces, the first wavelength-converted light 7 does not contain a long-afterglow fluorescent component due to the spin-forbidden transition of Cr3+. It is thus possible to obtain a high-output point light source having less saturation of fluorescence output when the light irradiation type cosmetic apparatus 10 emits light having high-power density that is emitted from a solid-state light source having a rated output of 1 W or more.
The wavelength converter 3A includes only the first phosphor 4 that contains fluorescence based on the electron energy transition of Cr3+, as a phosphor. The first phosphor 4 contains no activator other than Cr3+. Thus, light absorbed by the first phosphor 4 is converted into only the fluorescence based on the electron energy transition of Cr3+. Thus, the light irradiation type cosmetic apparatus 10 in which the first phosphor 4 contains no activator other than Cr3+ facilitates the design of output light to maximize the output proportion of the near-infrared fluorescent component.
The first phosphor 4 preferably has a garnet crystal structure. The ease of compositional deformation of the garnet phosphor enables the preparation of numerous phosphor compounds. Thus, when the first phosphor 4 has a garnet crystal structure, it is easy to adjust a crystal field around Cr3+ and to control the color tone of fluorescence based on the electron energy transition of Cr3.
Note that a phosphor having a garnet structure, especially an oxide, has a polyhedral particle shape close to a sphere and has excellent dispersibility in a phosphor particle group. Thus, when the first phosphor 4 has a garnet structure, it is relatively easy to manufacture the wavelength converter 3A having excellent optical transparency, which makes it possible to achieve high output of the obtained light irradiation type cosmetic apparatus 10. Since a phosphor with a garnet crystal structure has a record of practical application as a phosphor for LEDs, the light irradiation type cosmetic apparatus 10 in which the first phosphor 4 has a garnet crystal structure is highly reliable.
The first phosphor 4 is preferably an oxide-based phosphor, more preferably an oxide phosphor. Note that the oxide-based phosphor refers to a phosphor containing oxygen but not nitrogen.
An oxide is a stable substance in the atmosphere, and thus when an oxide phosphor is heated through high density photoexcitation with light emitted from a solid-state light source having a rated output of 1 W or more, the change in quality of a phosphor crystal due to oxidation in the atmosphere is less likely to occur compared to a nitride phosphor. When the first phosphor 4 is entirely an oxide-based phosphor, it is possible to obtain the light irradiation type cosmetic apparatus 10 having high reliability.
Note that the first phosphor 4 may contain two or more kinds of Cr3+-activated phosphors. When the first phosphor 4 contains two or more kinds of Cr3+-activated phosphors, it is possible to control at least the output light component in the near-infrared wavelength range. Thus, in the light irradiation type cosmetic apparatus 10 in which the first phosphor 4 contains two or more kinds of Cr3+-activated phosphors, it becomes easy to adjust the spectral distribution of the near-infrared fluorescent component.
<Sealant>
In the wavelength converter 3A, the first phosphor 4 is contained in the sealant 5. Preferably, the first phosphor 4 is dispersed in the sealant 5. When the first phosphor 4 is dispersed in the sealant 5, it becomes possible to efficiently absorb the primary light 6 emitted by the light source 2 and efficiently convert the wavelength thereof to that of near-infrared light. When the first phosphor 4 is dispersed in the sealant 5, the wavelength converter 3A can be easily formed into a sheet or film shape.
The sealant 5 is made from at least one of an organic material or an inorganic material. The sealant 5 is preferably made from at least one of a transparent (translucent) organic material or a transparent (translucent) inorganic material. An example of the organic material sealant is a transparent organic material, such as a silicone resin. An example of the inorganic material sealant is a transparent inorganic material, such as low melting point glass.
Note that the wavelength converter 3A is preferably made from an inorganic material. An inorganic material here means a material other than an organic material, and includes ceramics and metals as a concept. When the wavelength converter 3A is made from an inorganic material, the thermal conductivity thereof is higher than that of the wavelength converter containing an organic material such as a sealing resin, which facilitates the design of heat dissipation. Thus, even when the first phosphor 4 is photoexcited at high density by the primary light 6 emitted by the light source 2, it is possible to suppress the temperature rise of the wavelength converter 3A in an effective manner. Consequently, the temperature quenching of the first phosphor 4 in the wavelength converter 3A is suppressed, which makes it possible to achieve high output of emitted light.
When the wavelength converter 3A is made from an inorganic material, the sealant 5 is preferably made from an inorganic material. The inorganic material for the sealant 5 is preferably zinc oxide (ZnO). When the sealant 5 is made from an inorganic material, the heat dissipation of the first phosphor 4 is further enhanced, and thus a decrease in output of the first phosphor 4 due to temperature quenching is suppressed, which makes it possible to emit high-output near-infrared light.
Note that as a modified example of the light irradiation type cosmetic apparatus 10, it is possible to replace the wavelength converter 3A with a wavelength converter that does not include the sealant 5. In this case, particles of the first phosphor 4 can be fixed to each other using an organic or inorganic binder. It is also possible to fix particles of the first phosphor 4 to each other through a heating reaction of the first phosphor 4. A generally used resin-based adhesive, ceramics fine particles, low-melting-point glass, or the like can be used as the binder. In the wavelength converter without the sealant 5, it is possible to reduce the thickness of the wavelength converter.
<Action>
The action of the light irradiation type cosmetic apparatus 10 including the light emitting device 1A will be described. First, the primary light 6 emitted from the light source 2 of the light emitting device 1A is emitted on a front 3a of the wavelength converter 3A. The emitted primary light 6 penetrates the wavelength converter 3A. When the primary light 6 penetrates the wavelength converter 3A, the first phosphor 4 included in the wavelength converter 3A absorbs part of the primary light 6 and emits the first wavelength-converted light 7. In this way, the output light 15 including the primary light 6 and the first wavelength-converted light 7 is emitted from a back 3b of the wavelength converter 3A.
The output light 15 emitted from the light emitting device 1A is emitted to the outside from the irradiation port 110 of the light irradiation type cosmetic apparatus 10. When the output light 15 is emitted on human skin from the irradiation port 110 of the light irradiation type cosmetic apparatus 10, the output light 15 acts on the human skin to provide a hair growth suppression effect, an effect of the removal of spots, freckles, and the like. Specifically, the first wavelength-converted light 7 contained in the output light 15 is light that emits fluorescence based on the electron energy transition of Cr3+ and satisfying the above-described property (A) and contains a light component in a wavelength range suitable for easier absorption by melanin pigments than by blood and the like. Thus, when the output light 15 including the first wavelength-converted light 7 is emitted on human skin, a burn is less likely to occur, thermal efficiency is high, and destruction, coagulation, or the like occurs in melanin pigments and the like. When the melanin pigments and the like, which have been destroyed or coagulated, come to the surface through the skin's metabolism and are then peeled off and removed from the skin, it is expected that beautiful skin can be obtained through the suppression of unwanted hair growth and the removal of spots, freckles, and the like.
The light emitting device 1A and the light irradiation type cosmetic apparatus 10 including the light emitting device 1A are capable of increasing the intensity of near-infrared light penetrating a living body through the “biological window”, and thus have a high effect in suppressing unwanted hair growth, high performance in removing spots and freckles, and the like.
The first wavelength-converted light 7 contained in the output light 15 of the light emitting device 1A and the light irradiation type cosmetic apparatus 10 including the light emitting device 1A is fluorescence based on the spin-allowed electron energy transition of Cr3 of the first phosphor 4. Thus, with the light emitting device 1A and the light irradiation type cosmetic apparatus 10 including the light emitting device 1A, output light design that maximizes the output proportion of the near-infrared fluorescent component is easy, and thus filtering and removing extra light components is unnecessary and the energy efficiency is high.
(More specific examples of light emitting device (second to fifth light emitting devices)) In the above-described light irradiation type cosmetic apparatus 10 illustrated in
For example, it is possible to provide the light source 2 in the head part 30 and provide the wavelength converter 3 in the body part 20, as a configuration of a modified example of the light irradiation type cosmetic apparatus 10. This modified example of the light irradiation type cosmetic apparatus 10 has a configuration in which, usually, the primary light 6 is emitted from the light source 2 in the head part 30 to the wavelength converter 3 in the body part 20 and the output light 15 is emitted from the wavelength converter 3 toward the head part 30. The output light 15 emitted from the wavelength converter 3 toward the head part 30 usually includes the first wavelength-converted light 7 emitted from the wavelength converter 3 and the primary light 6 reflected by the wavelength converter 3. Thus, the light irradiation type cosmetic apparatus 10 and its modified example have multiple aspects in which the arrangements of the light source 2 and the wavelength converter 3 constituting the light emitting device 1 are different.
The wavelength converter 3A of the first light emitting device 1A includes at least a first phosphor as a phosphor and includes a phosphor other than the first phosphor, as necessary. Specifically, the wavelength converter 3A of the first light emitting device 1A can have one aspect in which only the first phosphor is included as a phosphor, and another aspect in which the first phosphor and a phosphor other than the first phosphor are included as phosphors. As described above, the light irradiation type cosmetic apparatus 10 and its modified example have multiple aspects in which the types of phosphors included in the wavelength converter 3 are different.
As described above, the first light emitting device 1A has multiple aspects in which the arrangements of the light source 2 and the wavelength converter 3 constituting the light emitting device 1 are different, and/or the types of phosphors included in the wavelength converter 3 are different. The following is a description of more specific examples of the light emitting device (second to fifth light emitting devices) 1B to 1E in which the arrangements of the light source 2 and the wavelength converter 3 of the first light emitting device 1A, and the types of phosphors included in the wavelength converter 3 are described more specifically.
Note that the second to fifth light emitting devices 1B to 1E are more specific examples of the first light emitting device 1A, and thus the first light emitting device 1A and the second to fifth light emitting devices 1B to 1E have the same basic configuration. Thus, in the following description of the second to fifth light emitting devices 1B to 1E, the first light emitting device 1A may also be referred to as appropriate.
The second light emitting device 1B illustrated in
The third light emitting device 1C illustrated in
The fourth light emitting device 1D illustrated in
The fifth light emitting device 1E illustrated in
The wavelength converter 3B of the second light emitting device 1B illustrated in
(Light Emitting Device (Second Light Emitting Device))
The light emitting device (second light emitting device) 1B includes the wavelength converter 3B (3) containing only the first phosphor 4 as a phosphor and generates the output light 15 using the first wavelength-converted light 7 and the primary light 6 that has penetrated the wavelength converter 3B.
For the second light emitting device 1B, the wavelength converter 3A of the first light emitting device 1A is described more specifically, and other configurations are simplified. The main difference between the second light emitting device 1B and the first light emitting device 1A is only in the wavelength converter 3B. Thus, the wavelength converter 3B is described below, and for other members, the description of their configurations and actions is omitted or simplified.
<Wavelength Converter>
The wavelength converter 3B includes the first phosphor 4 and the sealant 5. In the wavelength converter 3B, the first phosphor 4 is included in the sealant 5.
<Action>
The action of the light irradiation type cosmetic apparatus 10 including the light emitting device 1B will be described. First, the primary light 6 emitted from the light source 2 of the light emitting device 1B is emitted on the front 3a of the wavelength converter 3B. The emitted primary light 6 penetrates the wavelength converter 3B. When the primary light 6 penetrates the wavelength converter 3B, the first phosphor 4 included in the wavelength converter 3B absorbs part of the primary light 6 and emits the first wavelength-converted light 7. In this way, the output light 15 including the primary light 6 and the first wavelength-converted light 7 is emitted from the back 3b of the wavelength converter 3B.
The output light 15 emitted from the light emitting device 1B is emitted to the outside from the irradiation port 110 of the light irradiation type cosmetic apparatus 10. When the output light 15 is emitted on human skin from the irradiation port 110 of the light irradiation type cosmetic apparatus 10, the output light 15 acts on the human skin to provide a hair growth suppression effect, and an effect of the removal of spots, freckles, and the like. The action of the output light 15 acting on the human skin to provide the hair growth suppression effect, and the effect of the removal of spots, freckles, and the like is the same as that of the light irradiation type cosmetic apparatus 10 including the light emitting device 1A, and thus the description is omitted.
The light emitting device 1B and the light irradiation type cosmetic apparatus 10 including the light emitting device 1B are capable of increasing the intensity of near-infrared light penetrating a living body through the “biological window”, and thus have a high effect in suppressing unwanted hair growth, high performance in removing spots and freckles, and the like.
(Light Emitting Device (Third Light Emitting Device))
The light emitting device (third light emitting device) 1C includes the wavelength converter 3C (3) containing the first phosphor 4 and the second phosphor 8 as phosphors and generates the output light 15 using the first wavelength-converted light 7, the second wavelength-converted light 9, and the primary light 6 that has penetrated the wavelength converter 3C.
The third light emitting device 1C uses the wavelength converter 3C instead of the wavelength converter 3B of the second light emitting device 1B. The difference between the third light emitting device 1C and the second light emitting device 1B is only in the wavelength converter 3C. Thus, the wavelength converter 3C is described below, and for other members, the description of their configurations and actions is omitted or simplified.
<Wavelength Converter>
The wavelength converter 3C includes the first phosphor 4, the second phosphor 8, and the sealant 5. In the wavelength converter 3C, the first phosphor 4 and the second phosphor 8 are included in the sealant 5. That is, the wavelength converter 3C of the third light emitting device 1C further includes the second phosphor 8 that absorbs the primary light 6 and converts it into the second wavelength-converted light 9 having a wavelength longer than that of the primary light 6 and being different from the first wavelength-converted light 7.
The wavelength converter 3C is the same as the wavelength converter 3B of the second light emitting device 1B except that the wavelength converter 3C further includes the second phosphor 8. Thus, the second phosphor 8 is mainly described below, and the description of other configurations and actions is omitted or simplified.
[Second Phosphor]
The second phosphor 8 absorbs the primary light 6 and converts it into the second wavelength-converted light 9 having a wavelength longer than that of the primary light 6 and being different from the first wavelength-converted light 7. In the third light emitting device 1C, the wavelength converter 3C further includes the second phosphor 8 in addition to the first phosphor 4, and thus it is possible to emit white output light using additive mixing with the primary light 6 emitted by the light source 2, which is warm color light, for example.
As described above, when the wavelength converter 3C of the fifth light emitting device 1C further includes the second phosphor 8 in addition to the first phosphor 4, it becomes possible to control the shape of the fluorescence spectrum emitted by the wavelength converter 3C and the excitation properties. Thus, it is possible for the obtained light emitting device 1C and the light irradiation type cosmetic apparatus 10 including the light emitting device 1C to easily adjust the spectral distribution of the output light depending on use.
The second phosphor 8 included in the wavelength converter 3C is not limited as long as it can absorb the primary light 6 emitted by the light source 2 and emit the second wavelength-converted light 9 that is visible light. The second phosphor 8 is preferably a Ce3+-activated phosphor having, as a host, a compound having, as a main component, at least one selected from the group of compounds consisting of garnet-type, calcium ferrite-type, and lanthanum silicon nitride (La3Si4N11)-type crystal structures. The second phosphor 8 is preferably a Ce3+-activated phosphor having, as a host, at least one compound selected from the group of compounds consisting of garnet-type, calcium-ferrite-type, and lanthanum silicon nitride (La3Si4N11)-type crystal structures. When the above-described second phosphor 8 is used, it becomes possible to obtain output light having a large amount of light components from green-based to yellow-based light components.
As the second phosphor 8, for example, a Ce3*-activated phosphor having, as a host, a compound (B) having, as a main component, at least one selected from the group consisting of M3RE2(SiO4)3, RE3Al2(AlO4)3, MRE2O4, and RE3Si6N11 is used. As the second phosphor 8, for example, a Ce3+-activated phosphor having, as a host, at least one selected from the group consisting of M3RE2(SiO4)3, RE3Al2(AlO4)3, MRE2O4, and RE3Si6N11 is used. The second phosphor 8 is preferably a Ce3+-activated phosphor having, as a host, a solid solution having the above-described compound (B) as an end component. Note that in the compound (B), M is an alkaline earth metal, and RE is a rare earth element.
The above-described second phosphor 8 well absorbs light within a wavelength range of 430 nm or more and 480 nm or less and converts it with high efficiency to green to yellow-based light having the intensity maximum value within a wavelength range of 540 nm or more and less than 590 nm. Thus, by using the light source 2 that emits warm color light as the primary light 6 and using the second phosphor 8, it is possible to easily obtain a visible light component.
When the wavelength converter 3C includes the first phosphor 4 and the second phosphor 8, the first phosphor 4 preferably emits the first wavelength-converted light 7 by absorbing at least one of the primary light 6 emitted by the light source 2 or the second wavelength-converted light 9 emitted by the second phosphor 8. As described above, the first phosphor 4 is preferably a phosphor that absorbs the primary light 6 emitted by the light source 2 and emits the first wavelength-converted light 7 that is near-infrared light.
The first phosphor 4 may be a phosphor that absorbs the second wavelength-converted light 9 emitted by the second phosphor 8 and emits the first wavelength-converted light 7 that is near-infrared light. That is, the second phosphor 8 may be excited by the primary light 6 to emit the second wavelength-converted light 9, and the first phosphor 4 may be excited by the second wavelength-converted light 9 to emit the first wavelength-converted light 7. Here, even when the first phosphor 4 is a phosphor hardly excited by the primary light 6, it becomes possible to excite the first phosphor 4 through the second phosphor 8 by using fluorescence emitted by the second phosphor 8.
For this reason, when the first phosphor 4 absorbs the second wavelength-converted light 9 and emits the first wavelength-converted light 7, it becomes possible to select as the first phosphor 4 a phosphor that absorbs visible light. Thus, when the first phosphor 4 absorbs the second wavelength-converted light 9 and emits the first wavelength-converted light 7, the choice of the first phosphor 4 expands, and the industrial production of the light emitting device 1C and the light irradiation type cosmetic apparatus 10 including the light emitting device 1C becomes easy. When the first phosphor 4 absorbs the second wavelength-converted light 9 and emits the first wavelength-converted light 7, it becomes possible for the light emitting device 1C and the light irradiation type cosmetic apparatus 10 including the light emitting device 1C to emit the first wavelength-converted light 7 having a large near-infrared light component intensity.
Note that the second phosphor 8 may contain two or more kinds of Cr3+-activated phosphors. When the second phosphor 8 contains two or more kinds of Cr3+-activated phosphors, it is possible to control at least the output light component in the near-infrared wavelength range, which makes it easy to adjust the spectral distribution of the near-infrared fluorescent component.
<Action>
The action of the light irradiation type cosmetic apparatus 10 including the light emitting device 1C will be described. First, the primary light 6 emitted from the light source 2 is emitted on the front 3a of the wavelength converter 3C. The emitted primary light 6 penetrates the wavelength converter 3C. When the primary light 6 penetrates the wavelength converter 3C, the second phosphor 8 included in the wavelength converter 3C absorbs part of the primary light 6 and emits the second wavelength-converted light 9. Furthermore, the first phosphor 4 included in the wavelength converter 3C absorbs the primary light 6 and/or part of the second wavelength-converted light 9 to emit the first wavelength-converted light 7. In this way, the output light 15 including the primary light 6, the first wavelength-converted light 7, and the second wavelength-converted light 9 is emitted from the back 3b of the wavelength converter 3C.
The output light 15 emitted from the light emitting device 1C is emitted to the outside from the irradiation port 110 of the light irradiation type cosmetic apparatus 10. When the output light 15 is emitted on human skin from the irradiation port 110 of the light irradiation type cosmetic apparatus 10, the output light 15 acts on the human skin to provide a hair growth suppression effect, an effect of the removal of spots, freckles, and the like. The action of the output light 15 acting on the human skin to provide the hair growth suppression effect, and the effect of the removal of spots, freckles, and the like is the same as that of the light irradiation type cosmetic apparatus 10 including the light emitting device 1A, and thus the description is omitted.
The light emitting device 1C and the light irradiation type cosmetic apparatus 10 including the light emitting device 1C are capable of increasing the intensity of near-infrared light penetrating a living body through the “biological window”, and thus have a high effect in suppressing unwanted hair growth, high performance in removing spots and freckles, and the like.
(Light emitting device (fourth light emitting device)) The light emitting device (fourth light emitting device) 1D includes the wavelength converter 3D (3) containing only the first phosphor 4 as a phosphor and generates the output light 15 using the first wavelength-converted light 7 and the primary light 6 that has been reflected by the wavelength converter 3D.
The fourth light emitting device 1D uses the wavelength converter 3D instead of the wavelength converter 3B of the second light emitting device 1B. The difference between the fourth light emitting device 1D and the second light emitting device 1B is only in the wavelength converter 3D. Thus, the wavelength converter 3D is described below, and for other members, the description of their configurations and actions is omitted or simplified.
<Wavelength Converter>
The wavelength converter 3D includes the first phosphor 4 and the sealant 5. In the wavelength converter 3D, the first phosphor 4 is included in the sealant 5. The wavelength converter 3D is the same as the wavelength converter 3B of the second light emitting device 1B in that it includes the first phosphor 4 and the sealant 5, but the wavelength converter 3D has an optical action different from that of the wavelength converter 3B.
In the wavelength converter 3B of the second light emitting device 1B, the primary light 6 emitted on the wavelength converter 3B penetrates the wavelength converter 3B. In contrast, in the wavelength converter 3D of the fourth light emitting device 1D, most of the primary light 6 emitted on the wavelength converter 3D enters the wavelength converter 3D from the front 3a of the wavelength converter 3D, and the remainder is reflected by the front 3a.
The wavelength converter 3D is configured in such a manner that the emitted light of the primary light 6 enters from the front 3a of the wavelength converter 3D, and the output light of the first phosphor 4 is emitted from the front 3a of the wavelength converter 3D. Thus, most of the primary light 6 emitted on the wavelength converter 3D enters the wavelength converter 3D from the front 3a of the wavelength converter 3D, and the remainder is reflected by the front 3a.
<Action>
The action of the light irradiation type cosmetic apparatus 10 including the light emitting device 1D will be described. First, the primary light 6 emitted from the light source 2 is emitted on the front 3a of the wavelength converter 3D. Most of the primary light 6 enters the wavelength converter 3D from the front 3a of the wavelength converter 3D, and the remainder is reflected by the front 3a. In the wavelength converter 3D, the first wavelength-converted light 7 is emitted from the first phosphor 4 excited by the primary light 6, and the first wavelength-converted light 7 is emitted from the front 3a. In this way, the output light 15 including the primary light 6 and the first wavelength-converted light 7 is emitted from the front 3a of the wavelength converter 3D.
The output light 15 emitted from the light emitting device 1D is emitted to the outside from the irradiation port 110 of the light irradiation type cosmetic apparatus 10. When the output light 15 is emitted on human skin from the irradiation port 110 of the light irradiation type cosmetic apparatus 10, the output light 15 acts on the human skin to provide a hair growth suppression effect, and an effect of the removal of spots, freckles, and the like. The action of the output light 15 acting on the human skin to provide the hair growth suppression effect, and the effect of the removal of spots, freckles, and the like is the same as that of the light irradiation type cosmetic apparatus 10 including the light emitting device 1A, and thus the description is omitted.
The light emitting device 1D and the light irradiation type cosmetic apparatus 10 including the light emitting device 1D are capable of increasing the intensity of near-infrared light penetrating a living body through the “biological window”, and thus have a high effect in suppressing unwanted hair growth, high performance in removing spots and freckles, and the like.
(Light Emitting Device (Fifth Light Emitting Device))
The light emitting device (fifth light emitting device) 1E includes the wavelength converter 3E (3) containing the first phosphor 4 and the second phosphor 8 as phosphors and generates the output light 15 using the first wavelength-converted light 7, the second wavelength-converted light 9, and the primary light 6 that has been reflected by the wavelength converter 3E.
The fifth light emitting device 1E uses the wavelength converter 3E instead of the wavelength converter 3C of the third light emitting device 1C. The difference between the fifth light emitting device 1E and the third light emitting device 1C is only in the wavelength converter 3E. Thus, the wavelength converter 3E is described below, and for other members, the description of their configurations and actions is omitted or simplified.
<Wavelength Converter>
The wavelength converter 3E includes the first phosphor 4, the second phosphor 8, and the sealant 5. In the wavelength converter 3E, the first phosphor 4 and the second phosphor 8 are included in the sealant 5. That is, the wavelength converter 3E of the light emitting device 1E further includes the second phosphor 8 that absorbs the primary light 6 and converts it into the second wavelength-converted light 9 having a wavelength longer than that of the primary light 6 and being different from the first wavelength-converted light 7. The wavelength converter 3E is the same as the wavelength converter 3C of the third light emitting device 1C in that it includes the first phosphor 4, the second phosphor 8, and the sealant 5, but has an optical action different from that of the wavelength converter 3C.
The second phosphor 8 used in the wavelength converter 3E is the same as the wavelength converter 3C of the third light emitting device 1C, and thus the description is omitted. In the fifth light emitting device 1E, the wavelength converter 3E includes the second phosphor 8, and thus it is possible to emit white output light using additive mixing with the primary light 6 emitted by the light source 2, which is warm color light, for example.
As described above, when the first phosphor 4 and the second phosphor 8 are appropriately combined and used, it becomes possible to control the shape of the fluorescence spectrum of the first wavelength-converted light 7 and the excitation properties. That is, when the wavelength converter 3E of the fifth light emitting device 1E further includes the second phosphor 8 in addition to the first phosphor 4, it becomes possible to control the shape of the fluorescence spectrum of the first wavelength-converted light 7 and the excitation properties. Thus, it is possible for the obtained light emitting device 1E and the light irradiation type cosmetic apparatus 10 including the light emitting device 1E to easily adjust the spectral distribution of the output light depending on use.
In the wavelength converter 3C of the third light emitting device 1C, the primary light 6 emitted on the wavelength converter 3C penetrates the wavelength converter 3C. In contrast, in the wavelength converter 3E of the fifth light emitting device 1E, most of the primary light 6 emitted on the wavelength converter 3E enters the wavelength converter 3E from the front 3a of the wavelength converter 3E, and the remainder is reflected by the front 3a.
In the wavelength converter 3E, the emitted light of the primary light 6 enters from the front 3a of the wavelength converter 3E, and the output light of the first phosphor 4 is emitted from the front 3a of the wavelength converter 3E. Thus, most of the primary light 6 emitted on the wavelength converter 3E enters the wavelength converter 3E from the front 3a of the wavelength converter 3E, and the remainder is reflected by the front 3a.
<Action>
The action of the light irradiation type cosmetic apparatus 10 including the light emitting device 1E will be described. First, the primary light 6 emitted from the light source 2 is emitted on the front 3a of the wavelength converter 3E. Most of the primary light 6 enters the wavelength converter 3E from the front 3a of the wavelength converter 3E, and the remainder is reflected by the front 3a. In the wavelength converter 3E, the second wavelength-converted light 9 is emitted from the second phosphor 8 excited by the primary light 6, and the first wavelength-converted light 7 is emitted from the first phosphor 4 excited by the primary light 6 and/or the second wavelength-converted light 9. Then, the first wavelength-converted light 7 and the second wavelength-converted light 9 are emitted from the front 3a. In this way, the output light 15 including the primary light 6, the first wavelength-converted light 7, and the second wavelength-converted light 9 is emitted from the front 3a of the wavelength converter 3E.
The output light 15 emitted from the light emitting device 1E is emitted to the outside from the irradiation port 110 of the light irradiation type cosmetic apparatus 10. When the output light 15 is emitted on human skin from the irradiation port 110 of the light irradiation type cosmetic apparatus 10, the output light 15 acts on the human skin to provide a hair growth suppression effect, and an effect of the removal of spots, freckles, and the like. The action of the output light 15 acting on the human skin to provide the hair growth suppression effect, and the effect of the removal of spots, freckles, and the like is the same as that of the light irradiation type cosmetic apparatus 10 including the light emitting device 1A, and thus the description is omitted.
The light emitting device 1E and the light irradiation type cosmetic apparatus 10 including the light emitting device 1E are capable of increasing the intensity of near-infrared light penetrating a living body through the “biological window”, and thus have a high effect in suppressing unwanted hair growth, high performance in removing spots and freckles, and the like.
[Electronic Device]
An electronic device according to the present embodiment can be obtained using the light irradiation type cosmetic apparatus 10 including any one of the above-described light emitting devices 1A to 1E. That is, the electronic device according to the present embodiment is provided with the light irradiation type cosmetic apparatus 10 including any one of the above-described light emitting devices 1A to 1E. An example of such an electronic device includes one provided with the above-described light emitting device 1 (1A to 1E) and a fiber (light guide member) that guides the output light 15 emitted from the light emitting device 1.
The present embodiment is described in more detail below with examples and comparative examples, but the present embodiment is not limited to these examples.
An oxide phosphor was synthesized through a preparation procedure using a solid-state reaction. Specifically, an oxide phosphor expressed by the composition formula of Y3(Ga0.98, Cr0.02)2(GaO4)3 was synthesized. Note that the following compound powders were used as main raw materials in synthesizing the oxide phosphor.
Yttrium oxide (Y2O3): purity 3N, manufactured by Shin-Etsu Chemical Co., Ltd.
Gallium oxide (Ga2O3): purity 4N, manufactured by Nippon Rare Metal, Inc. Chromium oxide (Cr2O3): purity 3N, manufactured by Kojundo Chemical Lab. Co., Ltd.
First, the above raw materials were weighed to give a compound Y3(Ga0.98, Cr0.02)2(GaO4)3 of a stoichiometric composition. Then, dry mixing was performed using a mortar and a pestle, and a raw material for calcination was obtained.
The above-described calcination raw material was moved to an alumina crucible having a lid and was calcined for 2 hours in air at 1600° C. using a box-type electric furnace, and then the calcined material was lightly cracked to obtain a phosphor of an example 1. Note that the sample after calcination was confirmed to be Y3(Ga0.98, Cr0.02)2(GaO4)3 using an X-ray diffraction method.
(Evaluation of Emission Spectrum)
The emission spectrum of the phosphor was evaluated using a spectrofluorometer FP-6500 (manufactured by JASCO Corporation).
An oxide phosphor was synthesized through a preparation procedure using a solid-state reaction. Specifically, an oxide phosphor expressed by the composition formula of Gd3(Ga0.98, Cr0.02)2(GaO4)3 was synthesized. Note that the following compound powders were used as main raw materials in synthesizing the oxide phosphor.
Gadolinium oxide (Gd2O3): purity 3N, manufactured by Kojundo Chemical Lab. Co., Ltd.
Gallium oxide (Ga2O3): purity 4N, manufactured by Nippon Rare Metal, Inc. Chromium oxide (Cr2O3): purity 3N, manufactured by Kojundo Chemical Lab. Co., Ltd.
First, the above raw materials were weighed to give a compound Gd3(Ga0.98, Cr0.02)2(GaO4)3 of a stoichiometric composition. Then, dry mixing was performed using a mortar and a pestle, and a raw material for calcination was obtained.
The above-described calcination raw material was moved to an alumina crucible having a lid and was calcined for 2 hours in air at 1600° C. using a box-type electric furnace, and then the calcined material was lightly cracked to obtain a phosphor of an example 2. Note that the sample after calcination was confirmed to be Gd3(Ga0.98, Cr0.02)2(GaO4)3 using an X-ray diffraction method.
The emission spectrum of the phosphor was evaluated in the same manner as in the example 1. The result is illustrated in
An oxide phosphor was synthesized through a preparation procedure using a solid-state reaction. Specifically, an oxide phosphor expressed by the composition formula of (Gd0.75, La0.25)3(Ga0.98, Cr0.02)2(GaO4)3 was synthesized. Note that the following compound powders were used as main raw materials in synthesizing the oxide phosphor.
Gadolinium oxide (Gd2O3): purity 3N, manufactured by Kojundo Chemical Lab. Co., Ltd.
Lanthanum oxide (La2O3): purity 3N, manufactured by Kojundo Chemical Lab. Co., Ltd.
Gallium oxide (Ga2O3): purity 4N, manufactured by Nippon Rare Metal, Inc. Chromium oxide (Cr2O3): purity 3N, manufactured by Kojundo Chemical Lab. Co., Ltd.
First, the above raw materials were weighed to give a compound (Gd0.75, La0.25)3(Ga0.98, Cr0.02)2(GaO4)3 of a stoichiometric composition. Then, dry mixing was performed using a mortar and a pestle, and a raw material for calcination was obtained.
The above-described calcination raw material was moved to an alumina crucible having a lid and was calcined for 2 hours in air at 1400° C. using a box-type electric furnace, and then the calcined material was lightly cracked to obtain a phosphor of an example 3. Note that the sample after calcination was confirmed to be (Gd0.75, La0.25)3(Ga0.98, Cr0.02)2(GaO4)3 using an X-ray diffraction method.
(Evaluation of Emission Spectrum)
The emission spectrum of the phosphor was evaluated in the same manner as in the example 1. The result is illustrated in
An oxide phosphor was synthesized through a preparation procedure using a solid-state reaction. Specifically, an oxide phosphor expressed by the composition formula of Y3(Al0.98, Cr0.02)2(AlO4)3 was synthesized. Note that the following compound powders were used as main raw materials in synthesizing the oxide phosphor.
Yttrium oxide (Y2O3): purity 3N, manufactured by Shin-Etsu Chemical Co., Ltd.
Aluminum oxide (Al2O3): purity 3N, manufactured by Sumitomo Chemical Co., Ltd.
Chromium oxide (Cr2O3): purity 3N, manufactured by Kojundo Chemical Lab. Co., Ltd.
First, the above raw materials were weighed to give a compound Y3(Al0.98, Cr0.02)2(AlO4)3 of a stoichiometric composition. Then, dry mixing was performed using a mortar and a pestle, and a raw material for calcination was obtained.
The above-described calcination raw material was moved to an alumina crucible having a lid and was calcined for 2 hours in air at 1600° C. using a box-type electric furnace, and then the calcined material was lightly cracked to obtain a phosphor of a comparative example 1. Note that the sample after calcination was confirmed to be Y3(Al0.98, Cr0.02)2(AlO4)3 using an X-ray diffraction method.
(Evaluation of Emission Spectrum)
The emission spectrum of the phosphor was evaluated in the same manner as in the example 1. The result is illustrated in
(Summary of Evaluation of Emission Spectra)
It was found that the phosphors of the examples 1 to 3 emitted wavelength-converted light containing a greater amount of a broad spectral component having a fluorescence intensity maximum value in a wavelength range exceeding 710 nm, than a linear spectral component having a fluorescence intensity maximum value in the wavelength range of 680 to 710 nm.
Note that the above-described linear spectral component is a long-afterglow light component based on the electron energy transition (spin-forbidden transition) of 2T1 and 2E→4A2(t23) of Cr3+. The above-described broad spectral component is a short-afterglow light component based on an electron energy transition (spin-allowed transition) of 4T2→4A2.
Thus, with a light emitting device using the phosphors of the examples 1 to 3 as the first phosphor, it was found that a point light source containing a large amount of the near-infrared component could be easily made.
In a light emitting device using the phosphors of the examples 1 to 3 as the first phosphor, it was found that the saturation of the fluorescence output was low when excitation light of high light density was emitted, and achieving high output is easy.
In a light emitting device using the phosphors of the examples 1 to 3 as the first phosphor, it was found that the first wavelength-converted light 7 contains a large amount of a fluorescent component in the near-infrared wavelength range (650 to 1000 nm) in which light easily penetrates a living body, which is called a “biological window”. Thus, it was found that a light irradiation type cosmetic apparatus using the phosphors of the examples 1 to 3 as the first phosphor increased the intensity of near-infrared light penetrating a living body, and enhanced the effect of suppressing unwanted hair growth, the performance in removing spots and freckles, and the like.
A nitride phosphor was synthesized through a preparation procedure using a solid-state reaction. Specifically, a nitride phosphor expressed by the composition formula of (Ca0.997, Eu0.003)AlSiN3 was synthesized. Note that the following compound powders were used as main raw materials in synthesizing the nitride phosphor.
Calcium nitride (Ca3N2): purity 2N, manufactured by TAIHEIYO CEMENT CORPORATION Aluminum nitride (AlN): purity 3N, manufactured by Kojundo Chemical Lab. Co., Ltd.
Silicon nitride (Si3N4): purity 3N, manufactured by Denka Company Limited Europium nitride (EuN): purity 2N, manufactured by TAIHEIYO CEMENT CORPORATION
First, the above raw materials were weighed in a glove box in an N2 atmosphere to give a compound (Ca0.997, Eu0.003)AlSiN3 of a stoichiometric composition. Then, dry mixing was performed using a mortar and a pestle, and a raw material for calcination was obtained.
The above-described calcined raw material was moved to a boron nitride (BN) crucible having a lid and was calcined for 2 hours in an N2 (0.6 MPa) pressurized atmosphere at 1600° C. using a pressurized atmosphere controlled electric furnace, and then the calcined material was lightly cracked to obtain a phosphor of a comparative example 2. Note that the sample after calcination was confirmed to be (Ca0.997, Eu0.003)AlSiN3 using an X-ray diffraction method.
(Evaluation of Emission Lifetime)
The emission lifetime of the phosphors was evaluated using a Quantaurus-Tau compact fluorescence lifetime measurement device (manufactured by Hamamatsu Photonics K.K.). The result is illustrated in
Table 2 illustrates the time to reach 1/10 of the maximum emission intensity ( 1/10 afterglow): τ1/10.
(Summary of Evaluation of Emission Lifetime)
It was found that the phosphors of the examples 1 to 3 emitted wavelength-converted light containing a greater amount of a short-afterglow near-infrared component present in a wavelength range exceeding 710 nm, than a long-afterglow linear spectral component having a fluorescence intensity maximum value within the wavelength range of 680 to 710 nm.
Note that the above-described long-afterglow linear spectral component is the light component based on the 2T1 and 2E→4A2 electron energy transition (spin-forbidden transitions) of Cr3+. The above-described short-afterglow near-infrared component is a light component based on the electron energy transition (spin-allowed transition) of 4T2→4A2.
In a light irradiation type cosmetic apparatus using the above-described phosphors of the examples 1 to 3 as the first phosphor, it was found that a large amount of the near-infrared component is obtained, the saturation of the fluorescence output was low when high-output density light emitted from a solid-state light source having a rated output of 1 W or more was emitted, and achieving high output is easy.
An amount of 1.0 g of phosphor powder of the example 1 was molded using a hydraulic press machine under a pressure of 210 MPa to produce a compact having a diameter of 13 mm. A sintered compact of an example 4 was obtained by calcining the compact for 1 hour in air at 1400° C. using a box-type electric furnace.
An amount of 1.0 g of phosphor powder of the example 2 was molded using a hydraulic press machine under a pressure of 210 MPa to produce a compact having a diameter of 13 mm. A sintered compact of an example 5 was obtained by calcining the compact for 1 hour in air at 1400° C. using a box-type electric furnace.
An amount of 1.0 g of phosphor powder of the example 3 was molded using a hydraulic press machine under a pressure of 210 MPa to produce a compact having a diameter of 13 mm. A sintered compact of an example 6 was obtained by calcining the compact for 1 hour in air at 1400° C. using a box-type electric furnace.
An amount of 0.5 g of phosphor powder of the example 1 was molded using a hydraulic press machine under a pressure of 210 MPa to produce a compact having a diameter of 13 mm. A sintered compact of a comparative example 3 was obtained by calcining the compact for 2 hours in an N2 (0.6 MPa) pressurized atmosphere at 1700° C. using a pressurized atmosphere controlled electric furnace.
(Evaluation of Fluorescence Output Saturation)
For a fluorescence output saturation property, a phosphor was irradiated with blue LD light having a peak wavelength of 450 nm using an integrating sphere, and the emission of light by a phosphor pellet was observed using a multichannel spectrometer. Here, the rated output of blue LD light was varied from 0.93 to 3.87 W. The irradiation area of the phosphor was 0.785 mm2.
The entire contents of Japanese Patent Application No. 2020-106043 (filed on Jun. 19, 2020) are incorporated herein by reference.
Although the present embodiment has been described above, it is not limited to these descriptions, and various modifications can be made within the scope of the gist of the present embodiment.
The present disclosure is capable of providing a light irradiation type cosmetic apparatus that emits high-output light having a high proportion of a near-infrared fluorescent component under excitation with high-output light, and an electronic device using the light irradiation type cosmetic apparatus.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-106043 | Jun 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/022112 | 6/10/2021 | WO |
