JPWO2017119313A1 - Phosphor element and lighting device - Google Patents

Abstract

The phosphor element includes a support substrate and an optical waveguide made of a phosphor provided on the support substrate, and an incident surface is provided at one end in the longitudinal direction of the optical waveguide. An emission surface is provided at the other end in the longitudinal direction, and the phosphor is made of a single crystal doped with rare earth element ions, and the thickness of the optical waveguide is 3 μm or more and 80 μm or less. [Selection] Figure 1

Description

  The present invention relates to a phosphor element and an illumination device that emits white light.

  Recently, research on automobile headlights using a laser light source has been actively conducted, and one of them is a white light source combining a blue laser or an ultraviolet laser and a phosphor. The light density of the excitation light can be increased by condensing the laser light, and the light intensity of the excitation light can also be increased by condensing a plurality of laser lights on the phosphor. As a result, the luminous flux and the luminance can be increased simultaneously without changing the light emitting area. For this reason, a white light source combining a semiconductor laser and a phosphor has been attracting attention as a light source that replaces the LED. For example, the phosphor glass used in automotive headlights is the phosphor glass “Lumifas” manufactured by Nippon Electric Glass Co., Ltd., National Research and Development Corporation, National Institute for Materials Science, Tamra Manufacturing Co., Ltd. The body is considered.

  Non-Patent Document 1 proposes that white light is generated by irradiating an optical fiber made of phosphor glass with laser light.

  As an illumination device using a laser light source and a grating element, Patent Document 1 discloses a structure in which a reflector made of a grating element is arranged on the output side of a laser light source. In this apparatus, the phosphor is disposed outside the apparatus, and an optical component such as a lens for condensing light is necessary, which is problematic in terms of miniaturization.

  According to Patent Document 2, by converting YAG into a single crystal, even if the temperature rises, the conversion efficiency does not deteriorate, and high-efficiency fluorescence characteristics are exhibited, enabling application in the high power field. This material is capable of obtaining white light by irradiating with 450 nm blue excitation light and emitting yellow light which is a complementary color, and is being developed for application to projectors and headlights.

  For example, in an automobile headlight, as schematically shown in FIG. 15, it is conceivable to spatially separate a laser diode (LD) and a phosphor by using an optical system. That is, laser light is emitted from the blue semiconductor laser light source 41 as indicated by an arrow D, and is condensed on the phosphor element 48 as indicated by an arrow A by the condensing optical system 42. As a result, white light is emitted from the phosphor element 48 as indicated by an arrow B.

  However, the single crystal phosphor 50 has low mechanical strength due to the cleavage property unique to the single crystal, and it is difficult to attach the single crystal phosphor 50 to the container 43 alone. For this reason, the single crystal phosphor 50 is attached and fixed to the support substrate 49, and the laser beam A is irradiated toward the bottom surface of the support substrate 49.

Patent 5231990 Patent 5620562 Patent 3864943 WO 2013/077031 A1

"Materials Integration" Vol.17, No3, p.51-56, 2004 "Development of fluorescent glass" Furukawa Electric Times, No. 105, p24-29, January 2000 "Light source device for next-generation automotive headlamps" Vol. 61, No.1, p.41-46, May 2015, "Panasonic Technical Journal"

  The present inventor has examined a technique for generating white light from a phosphor made of a single crystal doped with a rare earth element. However, single crystal phosphors are fragile and difficult to handle when miniaturized. For this reason, as shown in FIG. 15, the single crystal phosphor was fixed on the support substrate, and the emitted light was observed by making blue light incident. However, it was found that color unevenness occurs in the white light B actually emitted from the single crystal phosphor.

  When the emitted light from the single crystal phosphor was observed, the color tone was different depending on the place, and there were many places where the target white light was not obtained. That is, color unevenness was observed in the emitted white light.

  An object of the present invention is to reduce color unevenness of emitted white light in an apparatus that generates white light using a single crystal phosphor doped with rare earth element ions.

The present invention comprises a support substrate, and an optical waveguide made of a phosphor provided on the support substrate,
An incident surface is provided at one end in the longitudinal direction of the optical waveguide, an exit surface is provided at the other end in the longitudinal direction of the optical waveguide, and the phosphor contains rare earth element ions. The phosphor element is made of a doped single crystal and has a thickness of 3 μm or more and 80 μm or less.

Further, the present invention is an illumination device including a light source that oscillates laser light and a phosphor element,
The phosphor element is the phosphor element, and white light is emitted from the optical waveguide.

  The present inventor examined the cause of color unevenness in the emitted white light in a light source that generates white light using a single crystal phosphor, and the concentration of rare earth element ions in the single crystal phosphor is determined depending on the location. As a result, it was found that the ion concentration has a light and shade. Here, when the laser light A is applied perpendicularly to the single crystal phosphor plate 50 as in the prior art, the light travels straight and passes through the single crystal phosphor plate 50 to be emitted. Then, the spectrum of the emitted light reflects the density of the rare earth ion concentration in the single crystal phosphor plate 50.

  Based on such knowledge, the present inventor has found that the color unevenness of the emitted light can be suppressed by providing the single crystal phosphor on the support substrate and setting the thickness of the single crystal phosphor to 80 μm or less. For this reason, when the single crystal phosphor provided on the support substrate is thinned, the propagating light is repeatedly reflected between the interface with the support substrate and the surface on the opposite side. It is thought that the influence of the density of rare earth ions is averaged.

From such a viewpoint, the thickness of the optical waveguide is set to 80 μm or less, preferably 50 μm or less, and more preferably 30 μm or less. This further reduces color unevenness and increases the coherence length of the emitted light.
On the other hand, by setting the thickness of the optical waveguide to 3 μm or more, further 10 μm or more, the excitation light can be coupled to the optical waveguide with high efficiency, so that the average output power of the emitted light is improved and it is easy to couple to the single mode light. Therefore, coherence can be ensured.

  Here, the thickness of the optical waveguide is a dimension of the optical waveguide viewed in a direction perpendicular to the surface of the support substrate, and corresponds to T shown in FIGS. The waveguide phosphor element of the present invention is a non-grating phosphor element that does not include a grating (diffraction grating) in the optical waveguide.

1 is a perspective view schematically showing a waveguide type phosphor element 1 of the present invention. 1 is a side view showing an illuminating device including a waveguide type phosphor element 1 and a light source 11. FIG. 1 is a side view showing an illuminating device including a waveguide phosphor element 1A and a light source 11. FIG. It is a side view which shows the illuminating device which consists of waveguide type phosphor element 1B and light source 11A. It is a perspective view which shows typically the waveguide type phosphor element 21 using a ridge type | mold optical waveguide. It is a transverse cross section showing typically waveguide type phosphor element 21 using a ridge type optical waveguide. It is sectional drawing which shows typically the waveguide type phosphor element 21A using a ridge type | mold optical waveguide. It is sectional drawing which shows typically the waveguide type phosphor element 21B using a ridge type | mold optical waveguide. (A), (b), (c) is a cross-sectional view schematically showing each waveguide type phosphor element. (A), (b) is a cross-sectional view which shows each waveguide type phosphor element typically, respectively. The illuminating device which concerns on other embodiment is shown. The lighting device concerning other embodiments is shown. 6 shows a lighting device according to another embodiment of the present invention. It is a schematic diagram which shows the example which utilized the waveguide type phosphor element 1 of the example of this invention for the headlamp use for motor vehicles. It is a schematic diagram which shows the example which utilized the phosphor element 48 of the prior art example for the headlamp use for motor vehicles.

Hereinafter, embodiments of the present invention will be described in detail.
As shown in FIGS. 1 and 2, the waveguide phosphor element 1 includes a support substrate 2, a lower clad layer 3 provided on the support substrate 2, and a phosphor provided on the lower clad layer 3. The slab type optical waveguide 4 and the upper clad layer 5 covering the upper surface of the optical waveguide 4 are provided. The slab type optical waveguide 4 has a thin plate shape and has an incident surface 4a on which laser light is incident and an output surface 4b that emits white light. 4c is the upper surface of the optical waveguide 4, and 4d is the bottom surface. When the longitudinal direction of the optical waveguide is F, the incident surface 4a is at one end in the longitudinal direction F of the optical waveguide 4, and the exit surface 4b is at the other end in the longitudinal direction F.

  As shown in FIG. 2, a light source 11 is installed facing the waveguide type phosphor element 1. The light source 11 has a substrate 12 and an active layer 13, and the active layer 13 faces the incident surface 4 a of the slab type optical waveguide 4. As shown in FIG. 1, the laser light emitted from the active layer 13 enters the slab type optical waveguide 4 as indicated by an arrow A and propagates through the optical waveguide 4. The propagating light undergoes wavelength conversion in the optical waveguide 4 and is repeatedly reflected many times on the upper surface 4 c and the bottom surface 4 d of the optical waveguide 4, and white light is emitted from the emission surface 4 b of the optical waveguide 4 as indicated by an arrow B. To do. Here, as a result of the propagation light being converted into fluorescence while being repeatedly reflected in the optical waveguide 4, the influence of the concentration of the doping component in the phosphor constituting the optical waveguide 4 is uniformed, and the white light B Color unevenness is reduced.

  The phosphor element 1A of FIG. 3 is provided on the support substrate 2, the lower clad layer 3 provided on the support substrate 2, the adhesive layer 7 provided below the lower clad layer 3, and the lower clad layer 3. The slab type optical waveguide 4 and the upper cladding layer 5 on the upper surface of the optical waveguide 4 are provided.

  The phosphor element 1B of FIG. 4 is on the support substrate 9, the lower clad layer 3 provided on the support substrate 9, the slab type optical waveguide 4 provided on the lower clad layer 3, and the upper surface of the optical waveguide 4 An upper cladding layer 5 is provided. Further, a light source 11A is mounted on the support substrate 9 of the phosphor element 1B via a solder layer 14, for example, and the active layer 13 of the light source 11A faces the slab type optical waveguide 4.

5 to 8 show examples of phosphor elements using ridge type optical waveguides.
The waveguide type phosphor element 21 of FIGS. 5 and 6 includes a support substrate 2, a lower clad layer 3 provided on the support substrate 2, a phosphor layer 20 provided on the lower clad layer 3, and An upper clad layer 22 is provided on the upper surface 20a of the phosphor layer 20 (the upper clad layer 22 is not shown in FIG. 5).

  For example, a ridge groove 26 is formed on the upper surface 20 a of the phosphor layer 20, and a ridge type optical waveguide 25 is formed. The ridge groove 26 can also be formed on the bottom surface 20b side. The optical waveguide 25 includes an entrance surface 25a and an exit surface 25b. Reference numeral 24 denotes an extending portion outside the ridge groove.

  A waveguide type phosphor element 21A shown in FIG. 7 is the same as the waveguide type phosphor element shown in FIG. 6, except that an adhesive layer 7 is provided between the lower clad layer 3 and the support substrate 2. Yes.

  Further, in the waveguide type phosphor element 21B shown in FIG. 8, a ridge groove 26 is formed on the bottom surface 20b side of the phosphor layer 20, and thus a ridge type optical waveguide 25 is formed.

  In another preferred embodiment, the optical waveguide comprises a core made of the single crystal phosphor, and a clad covers the core. The shape of the cross section of the core (cross section perpendicular to the longitudinal direction of the core) is a convex figure.

  The convex figure means that a line segment connecting any two points of the outer contour line of the core cross section is located inside the outer contour line of the core cross section. A convex figure is a general geometric term. Examples of such figures include triangles, quadrangles, hexagons, octagons, and other polygons, circles, ellipses, and the like. As the quadrangle, a quadrangle having an upper side, a lower side, and a pair of side surfaces is particularly preferable, and a trapezoid is particularly preferable.

  For example, as shown in FIG. 9A, a ridge type (channel type) optical waveguide 28 made of a phosphor is formed on the support substrate 2 via a lower clad layer 38. The cross-sectional shape of the optical waveguide 28 is a trapezoid, and the upper surface 28a is narrower than the lower surface 28b. An adhesive layer can also be formed between the clad layer 38 and the support substrate 2.

  In the element shown in FIG. 9B, a clad layer 29 is provided on the support substrate 2, and an optical waveguide 28 made of a phosphor is embedded in the clad layer 29. The clad layer 29 has an upper surface covering portion 29c that covers the upper surface of the optical waveguide, a side surface covering portion 29b that covers the side surface of the optical waveguide, and a bottom surface covering portion 29a located between the optical waveguide and the support substrate.

  In the element shown in FIG. 9C, a cladding layer 29 is provided on the support substrate 2, and an optical waveguide 31 made of a single crystal phosphor is embedded in the cladding layer 29. The clad layer 29 has an upper surface covering portion 29c that covers the upper surface of the optical waveguide, a side surface covering portion 29b that covers the side surface of the optical waveguide, and a bottom surface covering portion 29a between the optical waveguide and the support substrate. The optical waveguide 31 has a trapezoidal shape, and the upper surface 31a is wider than the lower surface 31b.

  In the element shown in FIG. 10A, an optical waveguide 28 made of a phosphor is formed on the support substrate 2 via a lower clad layer 38. An upper cladding layer 30 is formed on the side surface and the upper surface 28 of the optical waveguide 28 to cover the optical waveguide 28. The upper clad layer 30 has a side surface covering portion 30 b that covers the side surface of the optical waveguide 28 and an upper surface covering portion 30 a that covers the upper surface.

  In the element shown in FIG. 10B, an optical waveguide 31 made of a phosphor is formed. The cross-sectional shape of the optical waveguide 31 is a trapezoid, and the lower surface is narrower than the upper surface. The upper clad layer 30 includes a side surface covering portion 30 b that covers the side surface of the optical waveguide 31 and an upper surface covering portion 30 a that covers the upper surface.

  The illuminating device shown in FIG. 11 includes a light source module 55 and a waveguide type phosphor element 1. In the light source module 55, one or more light sources 11 are mounted on the support substrate 37. Although one light source 11 is illustrated in FIG. 11, the number of light sources is not limited. The light source 11 includes a substrate 12 and an active layer 13 thereon. The active layer 13 is connected to the pad 35 through a wire 36.

  The waveguide phosphor element 1 includes a support substrate 2, a lower clad layer 3 provided on the support substrate 2, and a phosphor layer 4 provided on the lower clad layer 3. The phosphor layer 4 functions as a slab type optical waveguide, and the incident surface 4 a of the phosphor layer faces the emission surface of the light source 11.

  In this example, the light emitted from the active layer 13 of the light source 11 enters the incident surface 4a of the slab type optical waveguide 4 made of a single crystal phosphor, and propagates through the optical waveguide as indicated by an arrow C. And the light which passed the fluorescent substance is radiate | emitted as white light like the arrow B from the output side end surface 4b.

  The lighting device shown in FIG. 12 is similar to that of FIG. However, in the light source module 55 </ b> A shown in FIG. 12, a plurality of light sources 11 are installed on the support substrate 37. Each emission surface of each light source 11 faces the incident surface 4a of the optical waveguide 4, and light emitted from each light source enters the optical waveguide 4, propagates as indicated by an arrow C, and then proceeds from the emission surface 4b to an arrow B. As shown, white light is emitted.

  The lighting device shown in FIG. 13 is similar to that in FIG. However, in the example of FIG. 13, a pair of ridge grooves 26 are formed in the single crystal phosphor layer 20, and a ridge type optical waveguide 25 is provided between the pair of ridge grooves 26. The optical waveguide 25 includes an entrance surface 25a and an exit surface 25b.

  In this example, the light emitted from the active layer 13 of the light source 11 enters the incident surface 25a of the ridge-type optical waveguide 25 made of a phosphor, and propagates through the optical waveguide. And the light which passed the fluorescent substance is radiate | emitted as white light like the arrow B from the output side end surface 25b.

In a preferred embodiment, a reflective film that reflects the emitted light from the optical waveguide is provided between the lower clad of the optical waveguide and the support substrate. As a result, the amount of radiated light emitted outside the element can be increased. Such a reflective film may be a metal film such as gold, aluminum, copper, silver, or a dielectric multilayer film.
When a metal film is used as the reflective film, a metal layer such as Cr, Ni, Ti, etc. can be formed as a buffer layer of the metal film so that the clad layer formed thereon is not peeled off. .

  In addition, an antireflection (AR) coat or a moth-eye structure is provided between the upper clad layer and the phosphor layer, so that reflection between the upper clad layer and the phosphor layer is achieved. Can be reduced.

The material of the lower clad layer and the upper clad layer may be a material having a refractive index smaller than that of the phosphor layer, and may be an adhesive layer. The upper cladding layer may be air, which is equivalent to the case without the upper cladding layer.
The material of such a cladding layer is preferably SiO ₂ , Al ₂ O ₃ , MgF ₂ , CaF ₂ , MgO or the like. Further, from the viewpoint of dissipating heat generated in the phosphor substrate through the support substrate, it is better to make the thermal conductivity higher than that of the phosphor, and Al ₂ O ₃ and MgO are particularly preferable as such materials.

  When the support substrate has a refractive index larger than that of the phosphor constituting the optical waveguide, the lower cladding layer is essential, so that the light is confined in the optical waveguide and the propagation loss of the waveguide is reduced. It is preferable from the viewpoint.

  A reflection film (not shown) can be provided on the outer end surface of the light source opposite to the phosphor element. A film can be provided on the end surface of the active layer on the phosphor element side so that the light source independently oscillates. Furthermore, low reflection films (not shown) can be provided on the entrance surface and the exit surface of the optical waveguide of the phosphor element.

The reflectance of these low reflection films is preferably 0.1% or less. However, if the reflectance at the end face is 0.1% or less, the low reflection film may not be provided.
Examples of the film material formed on the low reflection film include oxides such as silicon dioxide, tantalum pentoxide, and magnesium fluoride, or films laminated with fluorides such as magnesium fluoride and calcium fluoride.

  As the light source, a semiconductor laser made of a GaN material having high reliability is preferable for exciting an illumination phosphor. A light source such as a laser array arranged in a one-dimensional manner can also be realized. It may be a super luminescence diode or a semiconductor optical amplifier (SOA).

  The ridge-type optical waveguide can be obtained by, for example, physically processing and molding by cutting with an outer peripheral blade or laser ablation processing. Alternatively, the ridge type optical waveguide can be formed by dry etching.

The method for generating white light from the semiconductor laser and the phosphor is not particularly limited, but the following methods are conceivable.
Method of obtaining white light by generating yellow fluorescence with blue laser and phosphor Method of obtaining white light by generating red and green fluorescence with blue laser and phosphor Also, red and blue with phosphor from blue laser or ultraviolet laser Method of generating white fluorescence by generating green fluorescence Method of obtaining white light by generating blue and yellow fluorescence with a phosphor from a blue laser or ultraviolet laser

As the phosphor single crystal, Y ₃ Al ₅ O ₁₂ , Ba ₅ Si ₁₁ A ₁₇ N ₂₅ , and Tb ₃ Al ₅ O ₁₂ are preferable. Further, as a doping component to be doped in the phosphor, rare earth element ions such as Tb, Eu, Ce, and Nd are used.

  The specific material of the support substrate is not particularly limited, and may be glass such as lithium niobate, lithium tantalate, quartz glass, or quartz. However, in order to suppress the heat of the light source from being transmitted to the phosphor, or the wavelength conversion and the phosphor itself being heated from the outside, a support substrate having good heat dissipation characteristics can be used. In this case, alumina, aluminum nitride, silicon carbide, Si and the like can be exemplified.

  Further, each end face of the light source element and the phosphor element may be cut obliquely in order to suppress end face reflection. Further, the phosphor element and the support substrate may be bonded together by adhesion or direct bonding. The phosphor element may be formed on the support substrate by a film formation method such as sputtering or CVD.

In a preferred embodiment, an AR coat made of a dielectric multilayer film is formed on at least one of the entrance surface and the exit surface of the optical waveguide.
In another preferred embodiment, a single layer film made of a material having a refractive index lower than that of the material constituting the phosphor layer is formed. The thickness of such a single layer film does not need to be determined exactly as in the AR coating, and end face reflection can be reduced simply by forming a single layer film. Here, when a multilayer film is used, the degree of reflection suppression may be reduced or eliminated depending on the relationship between the refractive index and the thickness between the multilayer films, and it is necessary to control the thickness of each layer of the multilayer film. Therefore, the single layer film is superior. Thereby, the end surface reflectance of the phosphor element can be surely reduced as compared with the case where there is no single layer film. The thickness of the single layer film is preferably 1 μm or less.

  When the channel type optical waveguide is a ridge type optical waveguide, the width W of the channel type optical waveguide is an optical waveguide width in a cross section perpendicular to the longitudinal direction of the optical waveguide. The width of the optical waveguide is the width of the narrowest portion of the width in the cross section of the optical waveguide.

From the viewpoint of the present invention, the total length Lwg (see FIGS. 1 and 5) of the optical element is preferably 100 μm or more, and more preferably 200 μm or more. Further, from the viewpoint of obtaining white light from blue light and yellow light and reducing light attenuation, it is preferably 1 mm or less, and more preferably 500 μm or less.
The width W of the ridge type optical waveguide is preferably 10 μm to 100 μm from the viewpoint of the present invention.

  By arranging a plurality of light source elements in parallel on the array and inputting them to the phosphor, it is possible to realize a miniaturized and high output lighting device. Furthermore, it is possible to realize an illuminating device in which excitation light is propagated throughout the entire area of the fluorescent glass by generating a single light source element and the end surface of the fluorescent glass is folded back to generate white light from the entire area.

(Experiment 1)
Laser illumination modules as shown in FIGS. 1, 2 and 11 were produced.
Specifically, the lower cladding layer 3 made of SiO ₂ by a sputtering apparatus on the support substrate 2 made of aluminum nitride and a thickness of 1.0μm deposition, YAG (yttrium aluminum doped with Ce thereon Garnet) A phosphor plate made of a single crystal and having a thickness of 500 μm was directly bonded. Next, the phosphor plate was polished until the thickness shown in Table 1 was reached. Next, an upper clad layer 5 made of SiO ₂ was formed into a thickness of 1.0 μm on this single crystal phosphor layer by a sputtering apparatus, and a slab type optical waveguide 4 was formed.

  Then, it cut | disconnected to bar shape with the dicing apparatus, optically polished both end surfaces, formed a 0.1% AR coat in both end surfaces, and finally cut the chip | tip, and produced the waveguide type phosphor element 1. . The element 1 had a width of 1 mm and a length Lwg of 200 μm.

A module was manufactured by optically coupling a GaN-based blue laser light source 11 having an output of 30 mW to the waveguide type phosphor element 1 formed into a chip. Table 1 shows the evaluation of each example. However, each item was measured as follows.
(Average output)
The average output represents the time average of the total luminous flux. To measure the total luminous flux, an integrating sphere (spherical photometer) is used to turn on the light source to be measured and the standard light source for which the total luminous flux is priced, and compare them. In detail, it measured using the method prescribed | regulated by JISC7801.
(Color unevenness)
The light output from the end face 4b of the waveguide type phosphor element was evaluated with a chromaticity diagram using a luminance distribution measuring device. In the chromaticity diagram, when the median value is in the range of x: 0.3447 ± 0.005 and y: 0.3553 ± 0.005, “no color unevenness” is assumed. "There is unevenness".
(Coherence length)
The spectral line width was measured by an optical spectrum analyzer using a Michelson interferometer, and obtained from the following calculation formula.

Coherence length (Lc) = C / ΔV

C: Speed of light = 2.79979258 × 108 m / sec
ΔV: Line width (Hz)

  Thus, it has been found that color unevenness is not observed when the thickness of the optical waveguide is 80 μm or less. Moreover, the average output is increased by setting the thickness of the optical waveguide to 3 μm or more. Furthermore, when the thickness of the optical waveguide is 50 μm or less, the coherence length is further shortened.

(Experiment 2)
A laser illumination module was produced in the same manner as in Experiment 1.
However, in this example, the single crystal phosphor plate and the support substrate were bonded together by resin bonding. Next, the single crystal phosphor plate was polished in the same manner as in Example 1, and a clad layer having a thickness of 1.0 μm was formed on the upper side to obtain a slab type optical waveguide 4. The obtained device was subjected to the same test as in Experiment 1, and the same result as in Experiment 1 was obtained.

(Experiment 3)
Laser illumination modules as shown in FIGS. 5, 6, and 13 were produced.
Specifically, a thickness of 1.0μm deposited the lower cladding layer 3 made of SiO ₂ by a sputtering device to a supporting substrate 2 made of aluminum nitride, phosphor plate directly consisting of YAG single crystal doped with Ce After bonding, the phosphor plate was polished to a thickness T of 3 μm. Next, a ridge groove 26 having a width W of 3 μm and a depth of Tr 2 μm was formed by reactive ion etching, and a cladding layer 22 having a thickness of 1.0 μm was formed on the upper side to form a ridge type optical waveguide 25.

  Thereafter, it was cut into a bar shape with a dicing apparatus, both end surfaces were optically polished, 0.1% AR coating was formed on both end surfaces, and finally chip cutting was performed to produce a waveguide phosphor element 21A. . The element size was a width of 1 mm and a length Lwg of 200 μm.

  The waveguide type phosphor element 21A formed into a chip was optically coupled to a 30 mW GaN-based blue laser light source 11 to produce a module. As a result, white light having an average of 3 lm and a coherence length of 2 mm could be observed from the output side of the module. Further, it was confirmed that the color unevenness was in the range of the median x: 0.3447 ± 0.005 and y: 0.3553 ± 0.005 in the chromaticity diagram.

(Experiment 4)
An illumination module similar to that in Example 6 of Experiment 1 was produced. However, after processing the phosphor plate to a thickness of 50 μm, as shown in FIG. 12, an array module was manufactured by facing 10 laser light sources 11 arranged at intervals of 80 μm. When laser light was oscillated from each laser light source, white light with an average of 30 lm could be observed from the output side of the module. Further, it was confirmed that the color unevenness was in the range of the median x: 0.3447 ± 0.005 and y: 0.3553 ± 0.005 in the chromaticity diagram.

(Experiment 5)
A module was produced in the same manner as in Experiment 4. However, as shown in FIG. 14, the phosphor element 1 of the example of the present invention was used. The thickness of the optical waveguide made of the single crystal phosphor was set to 50 μm. As a result, white light with an average of 3 lm could be observed from the output side of the module. Further, it was confirmed that the color unevenness was in the range of the median x: 0.3447 ± 0.005 and y: 0.3553 ± 0.005 in the chromaticity diagram.

Claims (8)

A support substrate, and an optical waveguide made of a phosphor provided on the support substrate;
An incident surface is provided at one end in the longitudinal direction of the optical waveguide, an exit surface is provided at the other end in the longitudinal direction of the optical waveguide, and the phosphor contains rare earth element ions. A phosphor element comprising a doped single crystal, wherein the optical waveguide has a thickness of 3 μm or more and 80 μm or less.   The device according to claim 1, wherein the optical waveguide is a slab type optical waveguide.   The device according to claim 1, wherein the optical waveguide is a ridge-type optical waveguide.   4. The device according to claim 3, wherein a plurality of the ridge type optical waveguides are provided.   5. The device according to claim 4, wherein the plurality of ridge type optical waveguides confine light in each optical waveguide by ridge grooves.   5. The element according to claim 4, wherein the ridge-type optical waveguide comprises a core made of the phosphor, and a cross-sectional shape of the core forms a convex figure. An illumination device including a light source that oscillates laser light and a phosphor element,
The said fluorescent element is a fluorescent element as described in any one of Claims 1-6, and white light radiates | emits from the said optical waveguide, The illuminating device characterized by the above-mentioned. The apparatus according to claim 7, wherein a plurality of the light sources are provided.

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