JP2013092796A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device that converts excitation light to long wavelength light having longer wavelength than the excitation light and radiates the converted light, and that can radiate light having a desired wavelength with high efficiency.SOLUTION: The light source device comprises: an excitation light source (10) for radiating excitation light (L1); a wavelength conversion member (20) that is composed by forming on a translucent plate (22) a wavelength conversion layer (21) receiving excitation light (L1) from the excitation light source (10) and radiating long wavelength light (L2) having longer wavelength than the excitation light (L1), and has one surface to which the excitation light (L1) from the excitation light source (10) is incident; a light reflection member (30) that is provided on the one surface side where the excitation light (L1) is incident in the wavelength conversion member (20), and has an excitation light transmitting window (31) for transmitting the excitation light (L1); and a filter member (40) that is provided on the other surface side of the wavelength conversion member (20), and reflects the excitation light (L1) and transmits the long wavelength light (L2).

Description

  The present invention relates to a light source device that can be suitably used as a light source of a projector device, for example.

Conventionally, a short arc type high-pressure discharge lamp has been used as a light source of a projector apparatus. Thus, in recent years, a projector apparatus using a solid light emitting element such as a light emitting diode or a laser diode as a light source has been proposed (see Patent Document 1). The projector device using such a solid light emitting element does not require a high voltage power source, has a long service life of the solid light emitting element as a light source, and has excellent impact resistance, so that high voltage discharge is possible. This is advantageous compared to a projector apparatus using a lamp.
However, in the projector apparatus described above, it is necessary to use three types of solid light emitting elements that emit red, green, and blue light, respectively. Therefore, it is difficult to reduce the cost, and the amount of emitted light is low. Since there is no solid light emitting element that emits high green light, there is a problem that a sufficient amount of light emission as a projector device cannot be obtained.

In order to solve such a problem, a wavelength conversion member formed on a glass plate by an excitation light source that emits excitation light and a wavelength conversion layer made of a phosphor that converts the excitation light from the excitation light source into visible light Has been proposed (see Patent Document 2).
According to such a light source device, the excitation light from the excitation light source can be converted into red, green, and blue visible light by selecting the type of phosphor constituting the wavelength conversion layer. It is not necessary to use a kind of solid light-emitting element, and green light with a high light emission amount can be obtained.

However, such a light source device has the following problems.
The wavelength conversion layer in the wavelength conversion member is obtained by (1) a method in which a mixed liquid containing a binder and a phosphor is applied to the surface of a glass plate and dried, and then sintered at a temperature of 650 to 700 ° C., for example. 2) A sol-gel method in which a gel film is formed by applying a sol containing a metal alkoxide and a phosphor to the surface of a glass plate, followed by hydrolysis and polycondensation reaction, and firing this gel film. (3) Fluorescence Vapor deposition method in which a body is deposited on the surface of a glass plate, (4) A molded body for a wavelength conversion layer in which a phosphor is contained in a transparent resin such as a silicone resin, and the molded body is adhered to the glass plate Formed by methods, etc.

However, when the wavelength conversion layer is formed by any one of the above methods (1) to (3), since the obtained wavelength conversion layer has a small thickness, a part of the excitation light from the excitation light source. Is transmitted through the wavelength conversion layer, and as a result, it is difficult to emit light of a required wavelength with high efficiency.
On the other hand, when the wavelength conversion layer is formed by the method of (4) above, it is possible to obtain a wavelength conversion layer having a large thickness. However, the transparent resin forming the wavelength conversion layer receives excitation light. Or, since it is likely to be decomposed or deteriorated by heat due to excitation light, it is not suitable as a wavelength conversion layer used in a light source device of a projector device that requires a higher light emission amount.

JP 2002-268140 A JP 2004-341105 A

  The present invention has been made on the basis of the circumstances as described above, and an object thereof is to convert a pumping light into a long wavelength light having a wavelength longer than that of the pumping light. An object of the present invention is to provide a light source device that can emit light with high efficiency.

The light source device of the present invention includes an excitation light source that emits excitation light,
A wavelength conversion layer that receives excitation light from the excitation light source and emits long-wavelength light having a wavelength longer than that of the excitation light is formed on the translucent plate, and the excitation light from the excitation light source is incident on one surface thereof. A wavelength converting member,
A light reflection member having an excitation light transmission window that transmits the excitation light, provided on one surface side where the excitation light is incident on the wavelength conversion member;
And a filter member that is provided on the other surface side of the wavelength conversion member and reflects the excitation light and transmits the long wavelength light.

The light source device of the present invention includes an excitation light source that emits excitation light,
A wavelength conversion layer that receives excitation light from the excitation light source and emits long-wavelength light having a wavelength longer than that of the excitation light is formed on the translucent plate, and the excitation light from the excitation light source is incident on one surface thereof. A wavelength converting member,
A filter member that is provided on one side of the wavelength conversion member on which the excitation light is incident, has an excitation light transmission window that transmits the excitation light, reflects the excitation light, and transmits the long wavelength light;
And a light reflecting member provided on the other surface side of the wavelength converting member.

In the light source device according to the aspect of the invention, it is preferable that the wavelength conversion layer has long-wavelength light emitted by receiving the excitation light as green light.
The wavelength conversion layer is preferably formed by a solkel method or a vapor deposition method.

  According to the light source device of the present invention, even if a part of the excitation light emitted from the excitation light source passes through the wavelength conversion layer, the excitation light is reflected by the filter member or the light reflection member, so that the wavelength conversion layer In this case, the excitation light from the excitation light source can be converted into long wavelength light with high efficiency, and therefore light with a required wavelength can be emitted with high efficiency.

It is explanatory drawing which shows the structure of the light source device which concerns on the 1st Embodiment of this invention. It is sectional drawing for description which shows the structure in an example of a light reflection member. It is explanatory drawing which shows the state of the excitation light and long wavelength light in the light source device which concerns on 1st Embodiment. It is explanatory drawing which shows the structure of the light source device which concerns on the 2nd Embodiment of this invention. It is explanatory drawing which shows the state of the excitation light and long wavelength light in the light source device which concerns on 2nd Embodiment. It is explanatory drawing which shows the structure of the light source device which concerns on the 3rd Embodiment of this invention. It is explanatory drawing which shows the structure of the modification of the light source device which concerns on 1st Embodiment. It is explanatory drawing which shows the structure of the modification of the light source device which concerns on 2nd Embodiment. It is explanatory drawing which shows the structure of the light source device which concerns on other embodiment. It is explanatory drawing which shows the structure of the light source device which concerns on an Example.

Hereinafter, embodiments of the light source device of the present invention will be described.
[First Embodiment]
FIG. 1 is an explanatory diagram showing a configuration of a light source device according to the first embodiment of the present invention. This light source device has an excitation light source 10 that emits excitation light L1, and in front of the excitation light source 10, a plate-like shape in which the excitation light L1 from the excitation light source 10 is incident on one surface (left surface in the figure). A wavelength conversion member 20 is provided. In this example, the excitation light source 10 is arranged so that the direction of the optical axis of the excitation light L1 incident on the wavelength conversion member 20 from the excitation light source 10 is perpendicular to one surface of the wavelength conversion member 20. .

  In the wavelength conversion member 20, a wavelength conversion layer 21 made of a phosphor that receives the excitation light L1 from the excitation light source 10 and emits long-wavelength light L2 having a longer wavelength than the excitation light L1 is formed on the translucent plate 22. Has been configured. A protective layer (not shown) made of glass, for example, may be provided on the surface of the wavelength conversion layer 21. Further, in the illustrated example, the wavelength conversion member 20 is disposed such that the wavelength conversion layer 21 faces the side opposite to the excitation light source 10 side, and thus, the translucent plate 22 on which the wavelength conversion layer 21 is not formed. Is a surface on which the excitation light L1 from the excitation light source 10 in the wavelength conversion member 20 is incident.

A plate-like or film-like light reflecting member 30 having an excitation light transmission window 31 that transmits the excitation light L1 from the excitation light source 10 is provided on one side of the wavelength conversion member 20 where the excitation light L1 from the excitation light source 10 is incident. Is provided. On the other hand, a plate-like or film-like filter member 40 is provided on the other surface side of the wavelength conversion member 20.
In the illustrated example, a collimator lens 15 that focuses the excitation light L <b> 1 emitted from the excitation light source 10 is provided between the excitation light source 10 and the light reflecting member 30.

  As the excitation light source 10, a solid light emitting element such as a light emitting diode or a laser diode can be used. For example, a blue laser diode can be preferably used.

The long wavelength light L2 emitted from the wavelength conversion layer 21 in the wavelength conversion member 20 may be any of red light, green light, and blue light, but is preferably green light.
The phosphor constituting the wavelength conversion layer 21 can be appropriately selected according to the wavelength of the excitation light L1 emitted from the excitation light source 10 and the wavelength of the light emitted from the wavelength conversion layer 21, for example, blue When the wavelength conversion layer 21 that receives the excitation light L1 from the excitation light source 10 made of a light emitting diode and emits green light is formed, the chemical and thermal stability is high, and the humidity environment and the temperature environment change. However, it is preferable to use a β sialon green phosphor because the change in the fluorescence characteristics is small and the deterioration is difficult.

  Moreover, it is preferable that the thickness of the wavelength conversion layer 21 is 50-100 micrometers. When this thickness is too small, when the excitation light source 10 passes through the wavelength conversion layer 21, the probability of absorption / wavelength conversion is reduced, and the excitation light L <b> 1 is between the filter member 40 and the light reflection member 30. Since the mutual reflection is repeated, the radiation region from the wavelength conversion layer 21 is expanded, the luminance as the light source is lowered, and a sufficient amount of light as the projector device cannot be obtained. On the other hand, when this thickness is excessive, when the wavelength conversion member 20 receives a thermal history due to the excitation light L1, the thermal expansion of the material constituting the light transmitting plate 22 and the material constituting the wavelength conversion layer 21 is achieved. When stress due to the difference in rate occurs, a crack is generated in the wavelength conversion layer 21, and the wavelength conversion layer 21 may absorb water due to the crack and the light emission characteristics may be deteriorated. Further, in the case of the transmission type configuration as shown in FIG. 1, since the light transmitted through the wavelength conversion member 20 is reduced, the long-wavelength light L2 emitted from the wavelength conversion layer 21 is the wavelength of the light reflection member 30. The amount of repeated mutual reflection with the conversion member 20 increases, the amount of absorption by the light reflection member 30 and the wavelength conversion member 20 increases, and the luminance as a light source also decreases.

  As a method of forming the wavelength conversion layer 21, a method of applying a mixed liquid containing a binder and a phosphor to the surface of the light-transmitting plate 22 and drying it, and then sintering it at a temperature of 650 to 700 ° C., for example. In general, the phosphor particles are exposed on the surface, resulting in an uneven scattering surface. Also, it is difficult to obtain an optically flat surface by a method of dispersing in silicon resin or the like. For this reason, as a method of forming the wavelength conversion layer 21, after applying a sol containing a metal alkoxide and a phosphor to the surface of the light transmitting plate 22, a gel film is formed by performing a hydrolysis / polycondensation reaction. A sol-gel method for firing the gel film, a vapor deposition method for vapor-depositing a phosphor on the surface of the light-transmitting plate 22, and the like are suitable. The wavelength conversion layer 21 formed by these methods is preferable because it has an optically flat surface and the filter member 40 can be formed directly on the surface. Thereby, the wavelength conversion layer 21 having a uniform thickness can be obtained, and another optical layer can be formed on the wavelength conversion layer 21.

As the translucent plate 22, one that transmits both the excitation light L <b> 1 emitted from the excitation light source 10 and the long wavelength light L <b> 2 emitted from the wavelength conversion layer 21, for example, made of glass such as quartz glass is used. it can.
Moreover, although the thickness of the translucent board 22 is based also on a size, it is 0.6-1.5 mm, for example. Basically, in order to suppress the spread of light due to mutual reflection of the excitation light L1 and the long wavelength light L2, it is preferable that the thickness of the translucent plate 22 is thin.

The light reflecting member 30 is not particularly limited as long as it reflects both the excitation light L1 emitted from the excitation light source 10 and the long wavelength light L2 emitted from the wavelength conversion layer 21. Although a material made of a highly light reflective metal can be used, when a blue laser diode is used as the excitation light source 10 and a phosphor that emits green light is used as the wavelength conversion layer 21, as shown in FIG. ₂ and SiO ₂ , for example, a dielectric multilayer film 30a that reflects blue light in a wavelength range of 420 to 470 nm, and green light that is configured of TiO ₂ and SiO _{2 in} a wavelength range of 490 to 560 nm, for example. What consists of a laminated body with the dielectric multilayer film 30b to reflect can be used.
Such a light reflecting member 30 can be formed by, for example, a vapor deposition method.
The light reflecting member 30 may be provided integrally with the wavelength conversion member 20 or may be provided separately from the wavelength conversion member 20.

  The excitation light transmission window 31 of the light reflecting member 30 is not particularly limited as long as it transmits the excitation light L1. For example, the excitation light transmission window 31 may be formed of an opening or a material that transmits the excitation light L1. However, it is preferable to reflect the long wavelength light L2 emitted from the wavelength conversion layer 21. To give a specific example, for example, when the light reflecting member 30 is constituted by a laminate of the dielectric multilayer film 30a that reflects blue light and the dielectric multilayer film 30b that reflects green light, FIG. As shown in FIG. 2, when an excitation light transmitting window opening K is formed in the dielectric multilayer film 30a that reflects blue light, and a dielectric multilayer film 30b that reflects green light is used that transmits blue light. Good. According to such a configuration, since the long wavelength light L2 emitted from the wavelength conversion layer 21 is reflected by the dielectric multilayer film 30b in the excitation light transmission window 31, the long wavelength light L2 is transmitted from the excitation light transmission window 31. Leakage is prevented, and thus higher luminous efficiency can be obtained for the long wavelength light L2 emitted from the wavelength conversion layer 21.

The filter member 40 reflects the excitation light L1 emitted from the excitation light source 10 and transmits the long wavelength light L2 emitted from the wavelength conversion layer 21.
As the filter member 40, a member made of a dielectric multilayer film composed of TiO ₂ and SiO ₂ can be used.
Such a filter member 40 can be formed by, for example, a vapor deposition method. The filter member 40 may be provided integrally with the wavelength conversion member 20 or may be provided separately from the wavelength conversion member 20.

In the light source device described above, the excitation light L1 emitted from the excitation light source 10 is focused on the collimator lens 15 and then passed through the excitation light transmission window 31 of the light reflecting member 30 as shown in FIG. Thus, the light is incident on one surface of the wavelength conversion member 20 (one surface of the translucent plate 22 in the illustrated example). Then, when the excitation light L1 is incident on the wavelength conversion layer 21 in the wavelength conversion member 20, the long wavelength light L2 having a longer wavelength than the excitation light L1 is emitted from the wavelength conversion layer 21. Of the long wavelength light L2, the light traveling toward the filter member 40 is emitted to the outside through the filter member 40, and the light traveling toward the light reflecting member 30 is reflected by the light reflecting member 30. Thereafter, the light is radiated to the outside through the wavelength conversion member 20 and the filter member 40.
On the other hand, the excitation light L1 transmitted through the wavelength conversion layer 21 is reflected by the filter member 40 and then incident on the wavelength conversion layer 21 as shown in FIG. The excitation light L1 radiated from the long wavelength light and further transmitted through the wavelength conversion layer 21 is reflected by the light reflecting member 30, and then enters the wavelength conversion layer 21. As a result, the long wavelength light is emitted from the wavelength conversion layer 21. Light is emitted.

  According to such a light source device, even if a part of the excitation light L1 emitted from the excitation light source 10 passes through the wavelength conversion layer 21, the excitation light L1 is reflected by the filter member 40 or the light reflecting member 30. Thus, since the light is incident again on the wavelength conversion layer 21, the excitation light L1 can be converted into the long-wavelength light L2 with high efficiency, and therefore light of a required wavelength can be emitted with high efficiency.

[Second Embodiment]
FIG. 4 is an explanatory diagram showing the configuration of the light source device according to the second embodiment of the present invention. This light source device has an excitation light source 10 that emits excitation light L1, and in front of the excitation light source 10, a plate-like shape in which the excitation light L1 from the excitation light source 10 is incident on one surface (left surface in the figure). A wavelength conversion member 20 is provided. The excitation light source 10 is arranged such that the direction of the optical axis of the excitation light L1 incident on the wavelength conversion member 20 from the excitation light source 10 is perpendicular to one surface of the wavelength conversion member 20.

  In the wavelength conversion member 20, a wavelength conversion layer 21 made of a phosphor that receives the excitation light L1 from the excitation light source 10 and emits long-wavelength light L2 having a longer wavelength than the excitation light L1 is formed on the translucent plate 22. Has been configured. A protective layer (not shown) made of glass, for example, may be provided on the surface of the wavelength conversion layer 21. Further, in the illustrated example, the wavelength conversion member 20 is arranged such that the wavelength conversion layer 21 faces the side opposite to the excitation light source 10 side, and thus the light transmitting plate on which the wavelength conversion layer 21 is not formed. The surface 22 is a surface on which the excitation light L1 from the excitation light source 10 in the wavelength conversion member 20 is incident.

Excitation light emitted from the excitation light source 10 having an excitation light transmission window 41 that transmits the excitation light L1 from the excitation light source 10 on one surface side where the excitation light L1 from the excitation light source 10 is incident on the wavelength conversion member 20. A plate-like or film-like filter member 40 that reflects L1 and transmits the long-wavelength light L2 emitted from the wavelength conversion layer 21 is provided. On the other hand, a plate-like or film-like light reflecting member 30 is provided on the other surface side of the wavelength conversion member 20.
In the illustrated example, a collimator lens 15 that focuses the excitation light L <b> 1 emitted from the excitation light source 10 is provided between the excitation light source 10 and the filter member 40. Further, the collimator lens 15 and the filter member 40 are provided. The plate-like wavelength-selective mirror 45 that transmits the excitation light L1 from the excitation light source 10 and reflects the long-wavelength light L2 emitted from the wavelength conversion layer 21 is disposed between the wavelength conversion member 20 and For example, it is arranged in a state inclined at 45 degrees.

As the excitation light source 10 and the wavelength conversion member 20, the thing of the structure similar to the light source device which concerns on 1st Embodiment can be used. Moreover, as a material which comprises the light reflection member 30 and the filter member 40, the thing similar to the light source device which concerns on 1st Embodiment can be used.
The excitation light transmission window 41 of the filter member 40 is not particularly limited as long as it transmits the excitation light L1. However, it is preferable to use one that transmits the long wavelength light L2 emitted from the wavelength conversion layer 21. For example, it can be formed by an opening or a material that transmits both the excitation light L1 and the long wavelength light L2.
As the wavelength selective mirror 45, a mirror made of a dielectric multilayer film made of TiO ₂ and SiO ₂ can be used.

In the above light source device, the excitation light L1 emitted from the excitation light source 10 is focused on the collimator lens 15 and further transmitted through the wavelength selective mirror 45, and then, as shown in FIG. The light is incident on one surface of the wavelength conversion member 20 (one surface of the light transmitting plate 22 in the illustrated example) through the excitation light transmitting window 41.
Then, when the excitation light L1 is incident on the wavelength conversion layer 21 in the wavelength conversion member 20, the long wavelength light L2 having a longer wavelength than the excitation light L1 is emitted from the wavelength conversion layer 21. Of the long wavelength light L 2, the light traveling toward the filter member 40 is transmitted through the filter member 40, and further radiated to the outside by being reflected by the wavelength selective mirror 45, toward the light reflecting member 30. The light traveling forward is reflected by the light reflecting member 30, then passes through the wavelength conversion member 20 and the filter member 40, and is further reflected by the wavelength selective mirror 45 to be emitted to the outside.
On the other hand, the excitation light L1 transmitted through the wavelength conversion layer 21 is reflected by the light reflecting member 30 and then incident on the wavelength conversion layer 21 as shown in FIG. Then, after the long wavelength light is emitted from the excitation light L1 transmitted through the wavelength conversion layer 21 and reflected by the filter member 40, the excitation light L1 is incident on the wavelength conversion layer 21. Light is emitted.

  According to such a light source device, even if a part of the excitation light L1 emitted from the excitation light source 10 passes through the wavelength conversion layer 21, the excitation light L1 is reflected by the light reflecting member 30 or the filter member 40. As a result, the light is again incident on the wavelength conversion layer 21, so that the excitation light L1 from the excitation light source 10 can be converted into the long wavelength light L2 with high efficiency, and therefore light of a required wavelength is emitted with high efficiency. be able to.

[Third Embodiment]
FIG. 6 is an explanatory diagram showing a configuration of a light source device according to the third embodiment of the present invention. In this light source device, the excitation light source is arranged so that the optical axis of the excitation light L1 from the excitation light source 10 is incident on one surface of the wavelength conversion member 20 from a direction inclined with respect to the normal direction of the one surface of the wavelength conversion member 20. In other respects, the light source device according to the third embodiment has the same configuration as the light source device according to the first embodiment.
In the light source device having such a configuration, the angle formed by the optical axis of the excitation light L1 incident on one surface of the wavelength conversion member 20 and the normal line on one surface of the wavelength conversion member 20 is 3 to 10 °. Is preferred.

According to such a light source device, the same effect as the light source device according to the first embodiment can be obtained, and the following effect can be obtained.
That is, the excitation light L1 that has passed through the excitation light transmission window 31 of the light reflecting member 30 is incident on one surface of the wavelength conversion member 20 from the direction in which the optical axis is inclined with respect to the normal direction of the one surface of the wavelength conversion member 20. As a result, when the excitation light L1 transmitted through the wavelength conversion layer 21 is reflected by the filter member 40, the reflection angle becomes larger than 0 °, so that the excitation light L1 reflected by the filter member 40 is again transmitted. Since leakage from the excitation light transmission window 31 of the light reflecting member 30 when transmitted through the wavelength conversion layer 21 is prevented or suppressed, higher luminous efficiency can be obtained.

[Other Embodiments]
The optical devices according to the first to third embodiments of the present invention have been described above. However, the present invention is not limited to these embodiments, and various modifications as described below are possible. It is possible to add.
For example, in the first embodiment and the second embodiment, as shown in FIGS. 7 and 8, the wavelength conversion member 20 has the wavelength conversion layer 20 with the wavelength conversion layer 21 facing the excitation light source 10 side. Thus, the surface of the wavelength conversion layer 21 may be a surface on which the excitation light L1 from the excitation light source is incident.

In the second embodiment, the excitation light source 10 includes the wavelength conversion member 20 from a direction in which the optical axis of the excitation light L1 from the excitation light source 10 is inclined with respect to the normal direction of one surface of the wavelength conversion member 20. It may be arranged to be incident on one surface.
According to such a configuration, the same effect as that of the light source device according to the third embodiment, that is, when the excitation light L1 transmitted through the wavelength conversion layer 21 is reflected by the light reflecting member 30, the reflection angle thereof is Since it is greater than 0 °, the excitation light L1 reflected by the light reflecting member 30 is prevented or suppressed from leaking from the excitation light transmitting window 41 of the filter member 40 when the excitation light L1 is transmitted through the wavelength conversion layer 21 again. Therefore, higher luminous efficiency can be obtained.

  As shown in FIG. 9, in the light source device of the present invention, a plurality of excitation light sources 10 may be provided, and the excitation light source 10 emits light from the excitation light source L <b> 1 emitted from the excitation light source 10. The axis is arranged so as to intersect the normal direction of one surface of the wavelength conversion member 20 at, for example, 90 °, and is emitted from the excitation light source 10 on the optical path of the excitation light L1 from the excitation light source 10 to the wavelength conversion layer 20. A light reflection plate 16 that reflects the excitation light L1 toward the wavelength conversion member 20 and a focusing lens 17 that focuses the excitation light L1 reflected by the light reflection plate 16 may be provided.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

<Example 1>
In accordance with the configuration shown in FIG. 10, a light source device was manufactured under the following conditions.
Excitation light source (10):
A total of 12 1 W class blue laser diodes (with a peak wavelength of 445 nm) were arranged as the excitation light source (10).
Wavelength conversion member (20):
Using a sol in which β sialon particles with a median diameter D ₅₀ of 18 μm are dispersed as a phosphor, wavelength conversion with a thickness of 55 μm is performed on a translucent plate (22) made of quartz glass with a thickness of 0.8 mm by a sol-gel method. After forming the layer (21), the wavelength conversion member (20) was produced by performing mirror polishing on the surface of the wavelength conversion layer (21).
Light reflecting member (30):
By depositing silver on one surface of the wavelength conversion member (20) where the wavelength conversion layer (21) is not formed, the thickness of the excitation light transmission window (31) made of a circular opening having a diameter of 1 mm is 1 μm. A light reflecting member (30) was formed.
Filter member (40):
On the surface of the wavelength conversion layer (21) of the wavelength conversion member (20), a filter member (40) having a thickness of 2 μm made of several tens of dielectric multilayer films composed of TiO ₂ and SiO _{2 is} formed by vapor deposition. Formed. The filter member (40) has a wavelength region of 420 to 480 nm of light reflected by the filter member (40).

<Example 2>
A light source device having the same configuration as that of the light source device according to Example 1 was manufactured except that the thickness of the wavelength conversion layer (21) was 95 μm.

<Comparative example 1>
A light source device having the same configuration as that of the light source device according to Example 1 was produced except that the filter member (40) was not formed.

<Comparative example 2>
A light source device having the same configuration as that of the light source device according to Example 2 was produced except that the filter member (40) was not formed.

[Illuminance measurement of light source device]
About each of the light source device which concerns on Examples 1-2 and Comparative Examples 1-2, as shown in FIG. 10, the illuminance meter (P) is arrange | positioned in the front of a light source device, and the light radiate | emitted from the said light source device is shown. The illuminance was measured. Here, the distance from the wavelength conversion member (20) to the illuminance meter is 30 cm. The above results are shown in Table 1 below as relative illuminance when the illuminance by the light source device according to Comparative Example 1 is taken as 100.

  As is clear from the results in Table 1, according to the light source devices according to Example 1 and Example 2, the excitation light is converted into long wavelength light with higher efficiency than the light source devices according to Comparative Example 1 and Comparative Example 2. It was confirmed that light of a required wavelength can be emitted with high efficiency.

DESCRIPTION OF SYMBOLS 10 Excitation light source 15 Collimator lens 16 Light reflection plate 17 Focusing lens 20 Wavelength conversion member 21 Wavelength conversion layer 22 Light transmission plate 30 Light reflection member 30a, 30b Dielectric multilayer film 31 Excitation light transmission window 40 Filter member 41 Excitation light transmission window 45 Wavelength selective mirror K Aperture L1 Excitation light L2 Long wavelength light P Illuminometer

Claims (4)

An excitation light source that emits excitation light;
A wavelength conversion layer that receives excitation light from the excitation light source and emits long-wavelength light having a wavelength longer than that of the excitation light is formed on the translucent plate, and the excitation light from the excitation light source is incident on one surface thereof. A wavelength converting member,
A light reflection member having an excitation light transmission window that transmits the excitation light, provided on one surface side where the excitation light is incident on the wavelength conversion member;
A light source device comprising: a filter member provided on the other surface side of the wavelength conversion member that reflects the excitation light and transmits the long wavelength light. An excitation light source that emits excitation light;
A wavelength conversion layer that receives excitation light from the excitation light source and emits long-wavelength light having a wavelength longer than that of the excitation light is formed on the translucent plate, and the excitation light from the excitation light source is incident on one surface thereof. A wavelength converting member,
A filter member that is provided on one side of the wavelength conversion member on which the excitation light is incident, has an excitation light transmission window that transmits the excitation light, reflects the excitation light, and transmits the long wavelength light;
A light source device comprising: a light reflecting member provided on the other surface side of the wavelength conversion member.   3. The light source device according to claim 1, wherein the wavelength conversion layer has long-wavelength light emitted upon receiving the excitation light, which is green light. 4.   The light source device according to claim 1, wherein the wavelength conversion layer is formed by a sol-gel method or a vapor deposition method.

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