JP2016194697A - Fluorescent light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent light source device which is capable of highly efficiently emitting the fluorescent light generated inside a wavelength conversion member to the outside by effectively using the fluorescent light, and therefore obtains high light-emitting efficiency.SOLUTION: A fluorescent light source device comprises a light source for excitation, a wavelength conversion member 21 which converts the excitation light from the light source for excitation to light having a longer wavelength than the excitation light, and a substrate 31 which supports the wavelength conversion member 21. The wavelength conversion member 21 comprises a fluorescent member 22, and a photonic structure part 23 which is arranged on the fluorescent member 22 and in which a plurality of salients are formed on the surface thereof. A light reflection film 33 is provided between the fluorescent member 22 and the substrate 31. The photonic structure part 23 is composed of an inorganic compound layer made of metal oxide, and a light-receiving surface of excitation light and an emitting surface of fluorescent light are composed of a surface of the photonic structure part 23.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fluorescent light source device that emits fluorescence from a phosphor by exciting the phosphor with excitation light.

Conventionally, as a fluorescent light source device, one having a configuration in which a phosphor is irradiated with laser light as excitation light and fluorescence is emitted from the phosphor is known.
As shown in FIG. 8, a certain type of such fluorescent light source device has a barium sulfate on the surface of a substrate 62 made of an AIN sintered body provided with a heat dissipating member 65 having heat dissipating fins 65a on the back surface. A wavelength conversion member is provided in which a fluorescent member 61 made of a YAG sintered body is disposed via a layer 63 (see, for example, Patent Document 1). In this fluorescent light source device, the surface of the fluorescent member 61 is an excitation light receiving surface in the wavelength conversion member and a fluorescent light emitting surface.

  However, in such a fluorescent light source device, there is a problem that the fluorescence generated inside the fluorescent member 61 cannot be emitted from the fluorescence emitting surface with high efficiency, and thus the fluorescence cannot be used effectively. In addition, the fluorescent member 61 is heated by the fluorescent light that cannot be emitted from the fluorescent light emitting surface, and the fluorescent material itself becomes high temperature, resulting in temperature quenching, so that a sufficient fluorescent light beam cannot be obtained.

Thus, in the fluorescent light source device, in order to improve the emission efficiency of the fluorescence from the fluorescence emission surface, the periodic structure in which convex portions are periodically arranged on the surface of the wavelength conversion member that is the fluorescence emission surface Techniques for providing such are known.
However, since the fluorescent member is composed of a single crystal or polycrystalline phosphor such as a YAG sintered body, it is difficult to form a fine uneven structure with the desired dimensions on the fluorescent member itself. is there.
Therefore, a periodic structure layer made of a material having ease of processing such as a polymer material and having convex portions arranged on the surface is laminated on the fluorescent member, and the periodic structure layer can be constituted by the periodic structure layer. It is being considered. However, in particular, when the surface of the periodic structure layer is used as a fluorescence emitting surface and also used as an excitation light receiving surface, the shape of the periodic structure layer is deformed by the heat of the laser light that is the excitation light. Thus, there is a problem that the emission efficiency of fluorescence from the fluorescence emission surface of the wavelength conversion member is lowered.

JP 2011-198560 A

  The present invention has been made based on the circumstances as described above, and the purpose thereof is to effectively utilize the fluorescence generated inside the wavelength conversion member and to emit it outside with high efficiency. An object of the present invention is to provide a fluorescent light source device capable of obtaining high luminous efficiency.

The fluorescent light source device of the present invention includes an excitation light source,
A wavelength conversion member that converts excitation light from the excitation light source into light having a longer wavelength than the wavelength of the excitation light;
A fluorescent light source device comprising a substrate supporting the wavelength conversion member,
The wavelength conversion member includes a fluorescent member, and a photonic structure portion disposed on the fluorescent member and having a plurality of convex portions formed on the surface thereof,
A light reflecting film is provided between the fluorescent member and the substrate;
The photonic structure part is composed of an inorganic compound layer made of a metal oxide, and the excitation light receiving surface and the fluorescence emission surface are constituted by the surface of the photonic structure part.

  In the fluorescent light source device of the present invention, the inorganic compound layer includes a plurality of columnar units, and each of the plurality of columnar units extends in a direction away from the fluorescent member and has a minute space between adjacent columnar units. It is preferable that the material is porous.

In the fluorescent light source device of the present invention, the metal oxide constituting the inorganic compound layer is alumina (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), magnesium oxide (MgO), tin oxide (SnO ₂ ). , Tungsten oxide (WO ₃ ), yttrium oxide (Y ₂ O ₃ ), indium tin oxide (ITO), zirconia (ZrO ₂ ), tantalum oxide (Ta ₂ O ₅ ), titanium oxide (TiO ₂ ), niobium oxide (Nb) ₂ O ₅ ) and a mixture of zirconia (ZrO ₂ ) and titanium oxide (TiO ₂ ).

Moreover, in the fluorescence light source device of this invention, it is preferable that the diffuse reflection member is provided in the side surface of the said wavelength conversion member.
In the fluorescent light source device of the present invention, it is preferable that the direction in which the excitation light from the excitation light source enters the excitation light receiving surface is the same as the direction in which the convex portion in the photonic structure extends. .

  According to the fluorescent light source device of the present invention, the fluorescent light generated inside the wavelength conversion member can be effectively used and emitted to the outside with high efficiency, so that high luminous efficiency can be obtained.

It is explanatory drawing which shows the outline of a structure in an example of the fluorescence light source device of this invention. It is sectional drawing for description which shows the structure of the fluorescence light-emitting member in the fluorescence light source device of FIG. It is an enlarged view for explanation which expands and shows the wavelength conversion member in the fluorescence light-emitting member of FIG. It is a fragmentary sectional view for explanation which shows the surface structure of the photonic structure part of the wavelength conversion member of Drawing 3. It is explanatory drawing which shows the wavelength conversion member formation process in an example of the manufacturing method of the fluorescence light source device of this invention, Comprising: (a) is sectional drawing for description which shows a fluorescent member, (b) is on a fluorescent member. It is sectional drawing for description which shows the state in which the inorganic compound layer was formed. (C) is an explanatory view showing a soft mold, (d) is an explanatory sectional view showing a state in which the soft mold is pressed against a resist film formed on the inorganic compound layer, (e) These are sectional drawings for description which show the state by which the resist pattern film was formed on the inorganic compound layer. Moreover, (f) is sectional drawing for description which shows the state by which the inorganic compound layer was etched, (g) is sectional drawing for description which shows the structure of the obtained wavelength conversion member. It is a SEM photograph of the wavelength conversion member obtained by passing through the wavelength conversion member formation process concerning FIG. It is sectional drawing for description which shows the surface structure of the photonic structure part of the wavelength conversion member in the other example of the fluorescence light source device of this invention. It is sectional drawing for description which shows the structure of the wavelength conversion member in the conventional fluorescence light source device.

Hereinafter, embodiments of the fluorescent light source device of the present invention will be described.
FIG. 1 is an explanatory diagram showing an outline of the configuration of an example of the fluorescent light source device of the present invention, and FIG. 2 is an explanatory sectional view showing the configuration of a fluorescent light emitting member in the fluorescent light source device of FIG. 3 is an enlarged view for explaining the wavelength converting member in the fluorescent light emitting member of FIG. 2, and FIG. 4 is an explanatory view showing the surface structure of the photonic structure portion of the wavelength converting member of FIG. It is a fragmentary sectional view.
As shown in FIG. 1, the fluorescent light source device 10 is excited by a laser diode 11 and excitation light L that is disposed opposite to the laser diode 11 and is laser light emitted from the laser diode 11. And a fluorescent light emitting member 20 having a wavelength conversion member 21 that emits the fluorescent light L1.
A collimator lens 15 that emits the excitation light L incident from the laser diode 11 as a parallel light beam is disposed between the laser diode 11 and the fluorescent light emitting member 20 at a position close to the laser diode 11. A dichroic mirror 16 that transmits the excitation light L from the laser diode 11 and reflects the fluorescence L1 from the wavelength conversion member 21 in the fluorescence light emitting member 20 is disposed between the collimator lens 15 and the fluorescence light emitting member 20. For example, the lens 15 is disposed in a posture inclined at an angle of 45 ° with respect to the optical axis of the lens 15.
Here, in FIG. 1, the light of one laser diode 11 is used, but there are a plurality of laser diodes 11, a condenser lens is disposed in front of the wavelength conversion member 21 in the fluorescent light emitting member 20, and the condensed light. May be applied to the wavelength conversion member 21. Further, the excitation light L is not limited to the light from the laser diode 11, and may be one that collects the light from the LED as long as it can excite the phosphor in the wavelength conversion member 21, and further, mercury. In addition, light from a lamp enclosing xenon or the like may be used. When a light source having a width in the emission wavelength such as a lamp or LED is used, the wavelength of the excitation light is the main emission wavelength region. However, the present invention is not limited to this.

As shown in FIG. 2, the fluorescent light emitting member 20 has a substantially disk-shaped wavelength conversion member 21 provided on the surface (upper surface in FIG. 2) of a rectangular flat substrate 31.
As shown in FIGS. 3 and 4, the wavelength conversion member 21 includes a disk-shaped fluorescent member 22 and a substantially circular plate formed on the surface (the upper surface in FIGS. 3 and 4) of the fluorescent member 22. The photonic structure part 23 is shaped.
In the wavelength conversion member 21, the surface of the photonic structure portion 23 (upper surface in FIGS. 2 to 4) is an excitation light receiving surface and a fluorescence emitting surface.
A light reflecting film 33 made of a multilayer film is provided on the back surface of the wavelength conversion member 21, that is, the back surface of the fluorescent member 22 (the lower surface in FIGS. 2 to 3). An annular diffuse reflection member 34 is provided on the side surface of the wavelength conversion member 21 in close contact with the side surface. As the diffuse reflection member 34, for example, a material made of a mixture of silicone and diffusing particles such as alumina and titania, or a material obtained by drying a ceramic paste containing an alkali metal element or the like is used. As described above, the wavelength conversion member 21 is provided with the light reflection film 33 and the diffuse reflection member 34 to have a reflection function on the back surface and the side surface. Further, a bonding member (not shown) is interposed between the light reflection film 33 and the substrate 31, and the wavelength conversion member 21 is bonded onto the substrate 31 by the bonding member. As the joining member, solder, a silver sintered material, or the like is used from the viewpoint of exhaust heat. Further, a heat radiating member 39 made of a metal such as copper is disposed on the back surface of the substrate 31. The heat radiating member 39 is provided with heat radiating fins 39a.

The photonic structure portion 23 constituting the wavelength conversion member 21 is formed by forming a periodic structure 24 in which a plurality of convex portions 25 are two-dimensionally arranged on the fluorescence emission surface, that is, the surface of the photonic structure portion 23. Is. The periodic structure 24 forms a photonic structure.
Here, in the present invention, the photonic structure refers to a two-dimensional periodic structure. Specifically, on the surface of the photonic structure part, a plurality of protrusions are two-dimensionally and periodically arranged. The structure is shown.
In the example of this figure, the periodic structure 24 in the photonic structure portion 23 is a two-dimensional periodic array in which the substantially conical convex portions 25 are densely packed.

Further, in the periodic structure 24, the period d is set to a size of a range (Bragg condition) in which diffraction of fluorescence emitted from the phosphor constituting the fluorescent member 22 occurs.
Specifically, the period d of the periodic structure 24 is a value obtained by dividing the peak wavelength of fluorescence emitted from the phosphor by the refractive index of the material (specifically, the inorganic compound layer) constituting the periodic structure 24 ( Hereinafter, it is referred to as “optical length”) or a value of several times the optical length.
In the present invention, the period of the periodic structure means a center-to-center distance (nm) between adjacent convex portions in the periodic structure.
By setting the period d of the periodic structure 24 to a size in which the diffraction of the fluorescence L1 generated in the fluorescent member 22 occurs, the fluorescence L1 can be emitted from the surface of the fluorescent member 22 to the outside with high efficiency.

Further, an aspect ratio (hereinafter also referred to as “periodic structure aspect ratio”) which is a ratio (h / d) of the height h of the convex portion 25 to the period d in the periodic structure 24 is 0.2 or more. preferable.
By setting the aspect ratio in the periodic structure 24 to be 0.2 or more, the fluorescence emitted from the phosphors constituting the fluorescent member 22 can be efficiently emitted from the photonic structure portion 23 which is the fluorescent emission surface of the wavelength conversion member 21. It can be taken out from the surface.
In addition, when the aspect ratio of the periodic structure 24 is 0.2 or more, it is possible to suppress the excitation light L from being reflected on the surface of the photonic structure portion 23, that is, the surface of the wavelength conversion member 21. . Therefore, the excitation light L can be sufficiently taken into the fluorescent member 22 when the surface of the photonic structure portion 23 is irradiated with the excitation light L.

And the photonic structure part 23 consists of a metal oxide, and is also called the inorganic compound layer (henceforth "specific inorganic compound layer") which has a columnar structure extended in the direction away from the fluorescent member 22 (upward in FIGS. 2-4). .). That is, the photonic structure portion 23 is obtained by forming the periodic structure 24 on the surface of the specific inorganic compound layer.
The specific inorganic compound layer constituting the photonic structure portion 23 is composed of a plurality of columnar units (inorganic compound columnar units), and each of the plurality of columnar units extends in a direction away from the fluorescent member 22 and is adjacent to each other. It is a porous material in which a minute space is formed between columnar units.

Moreover, in the photonic structure part 23, it is preferable that each of the some convex part 25 which comprises the periodic structure 24 is comprised by the columnar unit. That is, it is preferable that the convex part 25 consists of one columnar unit.
By constituting the convex part 25 by the columnar unit, the convex part 25 can surely have an intended shape by a method for manufacturing a fluorescent light source device (a wavelength conversion member forming step) described later.

Specific examples of the material of the specific inorganic compound layer constituting the photonic structure portion 23 include alumina (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), magnesium oxide (MgO), tin oxide (SnO ₂ ), and tungsten oxide. (WO ₃ ), yttrium oxide (Y ₂ O ₃ ), indium tin oxide (ITO), zirconia (ZrO ₂ ), tantalum oxide (Ta ₂ O ₅ ), titanium oxide (TiO ₂ ), niobium oxide (Nb ₂ O ₅₎ And metal oxides such as zirconia (ZrO ₂ ) and titanium oxide (TiO ₂ ). Among these, since it has a thermal expansion coefficient approximate to the thermal expansion coefficient (6 × 10 ⁻⁶ to 8 × 10 ⁻⁶ / K) of the phosphor (LuAG, YAG), zirconia (thermal expansion coefficient) 10.5 × 10 ⁻⁶ / K), indium tin oxide (thermal expansion coefficient 6.8 × 10 ⁻⁶ / K) and titanium oxide (thermal expansion coefficient 7.9 × 10 ⁻⁶ / K) are preferable. In particular, zirconia is more preferable because of its small absorption coefficient (specifically, 13 cm ⁻¹ (absorption coefficient for light having a wavelength of 550 nm)).

Moreover, it is preferable that the specific inorganic compound layer which comprises the photonic structure part 23 is a thing with a large refractive index. Specifically, the refractive index is preferably equal to or higher than the refractive index value of the fluorescent member 22. According to the configuration of the photonic structure portion 23 with the specific inorganic compound layer having a refractive index higher than the refractive index value of the fluorescent member 23, the fluorescence incident on the interface between the fluorescent member 22 and the photonic structure portion 23 Refraction is caused by passing through. Therefore, since the direction of travel of the fluorescence is changed at the interface between the fluorescent member 22 and the photonic structure portion 23, it is suppressed that the fluorescence is confined inside the wavelength conversion member 21, and as a result, the fluorescence is converted into the photonic structure. The light can be emitted from the surface of the portion 23 to the outside with high efficiency.
Further, by using a specific inorganic compound layer having a higher refractive index than that of the fluorescent member 22, it is possible to form the periodic structure 24 having a small period d. Therefore, since the convex portion 25 constituting the periodic structure 24 can be designed with a small height even if the aspect ratio (periodic structure aspect ratio) is large, the periodic structure 24 can be easily formed. For example, in the wavelength conversion member forming step described later, a soft mold can be produced and a resist pattern film can be easily formed (imprint operation).

Moreover, the thickness of the photonic structure part 23 is 0.05-1.0 micrometer, for example.
In the example of this figure, the thickness of the photonic structure portion 23 is the height h of the convex portion 25.

The fluorescent member 22 contains a phosphor. Specifically, the fluorescent member 22 is made of a single crystal or polycrystalline phosphor, or a mixture of a single crystal or polycrystalline phosphor and a ceramic binder. It consists of a knot. That is, the fluorescent member 22 is composed of a single crystal or polycrystalline phosphor.
Here, in the sintered body of the mixture of the phosphor and the ceramic binder used as the fluorescent member 22, nano-sized alumina particles are used as the ceramic binder. And this sintered compact is obtained by mixing several mass%-several tens mass% ceramic binder with respect to 100 mass% of fluorescent substance, pressing the mixture, and baking.
Since the fluorescent member 22 is made of a single crystal or polycrystalline phosphor, the fluorescent member 22 has high thermal conductivity. Therefore, in the fluorescent member 22, since the heat generated by the irradiation of the excitation light L is efficiently exhausted, the fluorescent member 22 is suppressed from becoming high temperature.

The single crystal phosphor constituting the fluorescent member 22 can be obtained, for example, by the Czochralski method. Specifically, the seed crystal is brought into contact with the melted raw material in the crucible, and in this state, the seed crystal is pulled up in the vertical direction while rotating the seed crystal to grow the single crystal on the seed crystal. The body is obtained.
Moreover, the polycrystalline fluorescent substance which comprises the fluorescent member 22 can be obtained as follows, for example. First, raw materials such as a base material, an activator, and a firing aid are pulverized by a ball mill or the like to obtain raw material fine particles of submicron or less. Next, the raw material fine particles are sintered by, for example, a slip casting method. Thereafter, a polycrystalline phosphor having a porosity of 0.5% or less, for example, is obtained by subjecting the obtained sintered body to hot isostatic pressing.

Specific examples of the phosphor constituting the fluorescent member 22 include YAG (Y ₃ Al ₅ O ₁₂ ), LuAG, (Lu ₃ Al ₅ O ₁₂ ), CASN (CaAlSiN ₃ : Eu), and SCASN ((Sr, Ca). AlSiN ₃ : Eu) and the like.

  In addition, the thickness of the fluorescent member 22 is, for example, 0.05 to 2.0 mm from the viewpoint of the conversion efficiency (quantum yield) between the excitation light L and fluorescence and the exhaust heat property.

  As a material constituting the substrate 31, an aluminum substrate or the like through a heat radiation adhesive in which metal fine powder is mixed into a resin can be used. Moreover, the thickness of the board | substrate 31 is 0.5-1.0 mm, for example.

The fluorescent light source device 10 having the above-described configuration can be manufactured by, for example, obtaining the wavelength conversion member 21 through a specific process described below.
Specifically, the wavelength conversion member 21 forms an inorganic compound layer having a columnar structure extending in a direction away from the fluorescent member 22 on the fluorescent member 22 and etches the surface of the inorganic compound layer (hereinafter, referred to as “a”). It is also referred to as “wavelength conversion member forming step”).

The wavelength conversion member forming step will be specifically described with reference to FIG.
As shown in FIG. 5G, the wavelength conversion member 21 obtained through the wavelength conversion member formation step shown in FIG. 5 has the configuration of the photonic structure portion 23 according to FIG. Is different. That is, in the wavelength conversion member 21 according to FIG. 5G, the photonic structure portion 23 has a thin film portion 42 and a plurality of protrusions (two in FIG. 5G) provided on the thin film portion 42. Part 43. Further, the plurality of convex portions 43 have a truncated cone shape, and the plurality of convex portions 43 are arranged at regular intervals in a state of being separated from each other. Then, the periodic structure 41 in which the plurality of convex portions 43 are two-dimensionally arranged on the surface of the photonic structure portion 23 (the upper surface in FIG. 5G) by the thin film portion 42 and the plurality of convex portions 43. Is formed.

First, as shown in FIG. 5A, a fluorescent member 22 is prepared and washed with an organic solvent.
In the example of this figure, the fluorescent member 22 has a circular flat plate shape with a diameter of 50.8 mm and a thickness of 0.13 mm, and the front and back surfaces are polished.

Next, as shown in FIG. 5B, an inorganic compound layer (hereinafter referred to as “photonic structure”) for forming the photonic structure portion 23 on the entire surface of the fluorescent member 22 (the upper surface in FIG. 5B). Also referred to as “part formation layer.”) 23A is formed. The photonic structure portion forming layer 23A is an inorganic compound layer made of a metal oxide and having a columnar structure extending in a direction away from the fluorescent member 22, and has a substantially flat surface (upper surface in FIG. 5B). is there.
As a method for forming the photonic structure portion forming layer 23A, a sputtering method is preferably used.
According to the sputtering method, the form of the obtained sputtered film can be controlled by adjusting the sputtering conditions, so that the photonic structure portion forming layer 23A having the desired columnar structure can be easily obtained.
Here, in the present invention, the “sputtering method” is a concept including a reactive sputtering method. In the case of forming a sputtered film by the reactive sputtering method, a reactive sputtering apparatus is used.

In the obtained photonic structure portion forming layer 23A, the columnar unit forming the photonic structure portion forming layer 23A has a ratio of the vertical width to the horizontal width (hereinafter also referred to as “columnar unit aspect ratio”). It is preferable that it is 1.3 or more.
Since the columnar unit aspect ratio in the photonic structure portion forming layer 23A is in the above range, the photonic structure portion forming layer 23A has further improved workability by an etching method. 23 can have the intended shape.

In order to form the photonic structure portion forming layer 23A by the sputtering method, it is necessary to control the sputtering conditions.
Specifically, it is preferable to reduce the high-frequency voltage applied between the fluorescent member 22 and the target material and reduce the flow rate of the inert gas.
By reducing the applied high-frequency voltage, the temperature of the fluorescent member 22 during the formation of the sputtered film can be lowered. Therefore, recrystallization in the sputtered film formed on the fluorescent member 22 can be suppressed, and the resulting sputtered film can have the intended columnar structure.
By making the flow rate of the inert gas relatively small, the sputtered film formed on the fluorescent member 23 is dense, specifically, the columnar unit aspect ratio is large and a fine space is formed between the columnar units. And a high refractive index.
In order to make the sputtered film have a high refractive index, it is preferable to introduce oxygen gas together with inert gas.
Specifically, when a sputtering apparatus is used to form a zirconia sputtered film as the photonic structure part forming layer 23A, the high frequency power applied between the fluorescent member 22 and the target material (zirconia) is 450 W or less. Preferably, it is 250 W or less.
For example, the flow rate of an inert gas such as argon gas is preferably 1 to 20 sccm. Moreover, it is preferable that the flow volume of the oxygen gas introduce | transduced with an inert gas as needed is 0.1-3 sccm.
In the example of this figure, the photonic structure portion forming layer 23A is made of a zirconia sputtered film and has a thickness of about 600 nm (specifically, 550 nm). The photonic structure portion forming layer 23A is formed by using a sputtering apparatus, using zirconia as a target material, high-frequency power of 250 W, an argon gas flow rate of 20 sccm, and an oxygen gas flow rate of 0.5 sccm as an inert gas. Depending on conditions, it was formed over 4 hours. During the formation of the sputtered film, the temperature (surface temperature) of the fluorescent member 22 was 100 ° C. or lower.

  Thereafter, a resist film is obtained on the surface of the photonic structure portion forming layer 23A formed on the fluorescent member 22 (upper surface in FIG. 5B) by, for example, a spin coating method, and this resist film is patterned by a nanoimprint method.

As a technique for patterning a resist film by the nanoimprint method, first, as shown in FIG. 5C, a pattern (specifically, a plurality of concave portions corresponding to the periodic structure 41 in the photonic structure portion 23 to be formed). A soft mold 51 having a pattern in which 52 is arranged is formed. As the soft mold 51, for example, one made of a thermosetting material or one made of an ultraviolet curable material is used.
Then, using the nanoimprint apparatus, as shown in FIG. 5D, the soft mold 51 is pressed against the resist film formed on the photonic structure part forming layer 23A, thereby forming the soft mold 51 on the resist film. The transferred pattern is transferred. As a result, as shown in FIG. 5E, a resist pattern film 27 having a period of 460 nm is formed on the photonic structure portion forming layer 23A.
In the example of this figure, the resist pattern film 27 is formed so as to cover the entire surface of the photonic structure portion forming layer 23A, a thin film portion 28A formed on the surface of the photonic structure portion forming layer 23A, and this A plurality of convex portions 28B formed on the thin film portion 28A. The plurality of protrusions 28B have a constant interval (period (distance between the centers of the protrusions 28B) corresponding to the protrusions 43 constituting the periodic structure 41 of the photonic structure part 23 to be formed is 460 nm, etc. (Interval).

Then, a dry etching process is performed on the photonic structure portion forming layer 23A on which the resist pattern film 27 is formed on the surface, so that the surface (the upper surface in FIG. 5F) is obtained as shown in FIG. The photonic structure portion 23 having the periodic structure 41 is obtained.
A specific example of the dry etching method is an ICP (Inductive Coupling Plasma) etching method.
The formation conditions for forming the periodic structure 41 by this ICP etching method are as necessary or necessary depending on the shape of the periodic structure 41 (specifically, for example, the shape of the convex portion 43 and the periodic structure aspect ratio). Accordingly, the thickness is appropriately determined in consideration of the material of the photonic structure portion forming layer 23A, the columnar unit aspect ratio, and the like.
Specifically, for example, silane gas (SiH ₄ ), silicon tetrafluoride gas (SiF ₄ ), diborane gas (B ₂ H ₆ ), boron trichloride gas (BCl ₃ ), or the like is used as the etching gas. The high frequency power is 100 to 700 W, and the bias power is 1 to 30 W.
In the example of this figure, the periodic structure 41 of the photonic structure portion 23 is formed by using boron trichloride gas (BCl ₃ ) as an etching gas by an ICP etching method, with a high-frequency power of 700 W and a bias power of 20 W. It is formed with a processing time of 350 seconds.

Thereafter, the remaining film 27A of the resist pattern film 27 left on the formed photonic structure portion 23 is removed with an organic solvent, whereby the wavelength conversion member 21 having the configuration as shown in FIG. obtain.
In the example of this figure, the SEM photograph of the obtained wavelength conversion member 21 is shown in FIG. The columnar unit aspect ratio of the wavelength conversion member 21 was 9.3.

  Then, the wavelength conversion member 21 obtained in this way is bonded onto the substrate 31 with the light reflection film 33 and the diffuse reflection member 34 provided as necessary, thereby obtaining the fluorescent light emitting member 20, and this fluorescence. The fluorescent light source device 10 is manufactured by arranging the light emitting member 20, the laser diode 11, and other components at appropriate positions.

  In the fluorescent light source device 10, the excitation light L that is laser light emitted from the laser diode 11 is converted into parallel rays by the collimator lens 15. Thereafter, the excitation light L passes through the dichroic mirror 16 and is irradiated substantially perpendicularly to the excitation light receiving surface of the wavelength conversion member 21 in the fluorescent light emitting member 20, that is, the surface of the photonic structure portion 23. The light enters the fluorescent member 22 through the portion 23. And in the fluorescent member 22, the fluorescent substance which comprises the said fluorescent member 22 is excited. Thereby, fluorescence is emitted in the fluorescent member 22. This fluorescence is emitted from the fluorescence emission surface, that is, the surface of the photonic structure portion 23, reflected in the vertical direction by the dichroic mirror 16, and then emitted to the outside of the fluorescence light source device.

In such a fluorescent light source device 10, the wavelength conversion member 21 is formed by forming the photonic structure portion 23 on the surface of the fluorescence member 22, and the excitation light receiving surface and the fluorescence emission are formed by the surface of the photonic structure portion 23. The surface is configured. On the surface of the photonic structure portion 23, a periodic structure 24 is formed in which approximately conical convex portions 25 are two-dimensionally arranged. Therefore, the fluorescence radiated from the phosphor constituting the fluorescent member 22 can be taken out from the surface of the photonic structure portion 23 that is the fluorescent emission surface of the wavelength conversion member 21 with high efficiency. Moreover, since the fluorescence can be extracted from the wavelength conversion member 21 with high efficiency, the fluorescence member 22 is suppressed from being heated by the fluorescence that cannot be emitted from the fluorescence emission surface. Therefore, since the temperature rise of the fluorescent member 22 in the wavelength conversion member 21 is suppressed, it is possible to suppress a reduction in the amount of fluorescent light due to the occurrence of temperature quenching in the phosphor.
Moreover, since the material of the photonic structure portion 23 is an inorganic compound (metal oxide), the shape thereof is not deformed by the influence of heat such as the heat of the laser light that is the excitation light L. Therefore, in the wavelength conversion member 21, fluorescence can be extracted from the fluorescence emission surface over a long period of time with high efficiency.
Therefore, according to the fluorescent light source device 10, since the fluorescence generated inside the wavelength conversion member 21 can be effectively used and emitted to the outside with high efficiency, high luminous efficiency can be obtained.

  Further, in this fluorescent light source device 10, since the wavelength conversion member 21 is composed of the fluorescent member 22 and the photonic structure portion 23, it is not necessary for the fluorescent member 22 to have a periodic structure. And the specific inorganic compound layer which comprises the photonic structure part 23 has the outstanding workability (workability). Therefore, the periodic structure 24 having the desired shape can be easily formed through the wavelength conversion member forming step.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.
For example, the wavelength conversion member only needs to have a photonic structure formed on a fluorescent member formed of a specific inorganic compound layer, and the photonic structure (periodic structure) in the photonic structure is shown in FIGS. It is not limited to the periodic structure according to FIG. Specifically, the wavelength conversion member may have a structure as shown in FIG.
Specifically, the photonic structure portion 23 according to FIG. 7A includes a thin film portion 42 provided on the surface of the fluorescent member 22 and a plurality of (in FIG. 7A) provided on the thin film portion 42. The photonic structure portion 23 has the same configuration as that of the photonic structure portion 23 shown in FIG. 1 except that it is constituted by four (4) weight-like (for example, substantially conical) convex portions 43. The photonic structure portion 23 according to FIG. 7B is the same as the photonic structure portion 23 according to FIG. 7A except that the shape of the convex portion 43 is a frustum shape (for example, a truncated cone shape). It has the structure of. In the photonic structure portion 23 of FIG. 7C, the convex portion 43 has a sectional shape in the height direction of the convex portion 43 that is hexagonal, and the plurality of convex portions 43 are separated from each other. The photonic structure portion 23 has the same configuration as that of the photonic structure portion 23 shown in FIG. In the example of FIG. 7C, the cross-sectional shape in the direction perpendicular to the height direction of the convex portion 43 is circular.
Here, when the shape of the convex portion 43 is such that the tip portion 43a is flat as shown in FIGS. 5 (g), 7 (b) and 7 (c), The dimension (maximum dimension) of the tip part 43a is less than the wavelength of the excitation light L.

As shown in FIG. 5G and FIGS. 7A to 7C, when the photonic structure portion 23 has a configuration having a thin film portion 42 and a convex portion 43, a photonic structure is formed. Since high adhesiveness is obtained between the structure part 23 and the fluorescent member 22, the occurrence of peeling between the photonic structure part 23 and the fluorescent member 22 is suppressed.
Further, as shown in FIGS. 5G, 7B, and 7C, when the tip 43a of the convex portion 43 is flat, for example, in the manufacturing process of the fluorescent light source device. In the process of assembling the constituent members, the occurrence of breakage due to contact of the other constituent members (for example, the dichroic mirror 16) with the tip portion 43a of the convex portion 43 is suppressed.

Moreover, the wavelength conversion member should just be that the fluorescence emission surface in the wavelength conversion member was formed by the surface of the photonic structure part, and the excitation light receiving surface in the wavelength conversion member was formed by the back surface of the fluorescence member, for example There may be.
Moreover, the structure of the whole fluorescence light source device is not limited to what is shown in FIG. 1, A various structure is employable.

DESCRIPTION OF SYMBOLS 10 Fluorescence light source device 11 Laser diode 15 Collimator lens 16 Dichroic mirror 20 Fluorescence light emission member 21 Wavelength conversion member 22 Fluorescence member 23 Photonic structure part 23A Inorganic compound layer (photonic structure part formation layer)
24 periodic structure 25 convex portion 27 resist pattern film 27A residual film 28A thin film portion 28B convex portion 31 substrate 33 light reflection film 34 diffuse reflection member 39 heat dissipation member 39a heat dissipation fin 41 periodic structure 42 thin film portion 43 convex portion 51 soft mold 52 concave portion 61 Fluorescent member 62 Substrate 63 Barium sulfate layer 65 Heat radiating member 65a Heat radiating fin L Excitation light

Claims (5)

An excitation light source;
A wavelength conversion member that converts excitation light from the excitation light source into light having a longer wavelength than the wavelength of the excitation light;
A fluorescent light source device comprising a substrate supporting the wavelength conversion member,
The wavelength conversion member includes a fluorescent member, and a photonic structure portion disposed on the fluorescent member and having a plurality of convex portions formed on the surface thereof,
A light reflecting film is provided between the fluorescent member and the substrate;
The photonic structure portion is composed of an inorganic compound layer made of a metal oxide, and an excitation light receiving surface and a fluorescence emission surface are constituted by the surface of the photonic structure portion.   The inorganic compound layer includes a plurality of columnar units, each of the plurality of columnar units extends in a direction away from the fluorescent member, and is a porous layer in which a minute space is formed between adjacent columnar units. The fluorescent light source device according to claim 1, wherein the fluorescent light source device is provided. The metal oxide constituting the inorganic compound layer includes alumina (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), magnesium oxide (MgO), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), yttrium oxide ( Y ₂ O ₃ ), indium tin oxide (ITO), zirconia (ZrO ₂ ), tantalum oxide (Ta ₂ O ₅ ), titanium oxide (TiO ₂ ), niobium oxide (Nb ₂ O ₅ ), and zirconia (ZrO ₂ ) The fluorescent light source device according to claim 1, wherein the fluorescent light source device is a mixture of titanium oxide and titanium oxide (TiO ₂ ).   The fluorescent light source device according to any one of claims 1 to 3, wherein a diffuse reflection member is provided on a side surface of the wavelength conversion member.   The direction in which the excitation light from the excitation light source is incident on the excitation light receiving surface is the same as the direction in which the convex portion of the photonic structure extends. A fluorescent light source device according to claim 1.