WO2013175706A1

WO2013175706A1 - Optical element, light-emitting device, and projection device

Info

Publication number: WO2013175706A1
Application number: PCT/JP2013/002682
Authority: WO
Inventors: 瑞穂冨山; 鈴木　尚文
Original assignee: 日本電気株式会社
Priority date: 2012-05-25
Filing date: 2013-04-22
Publication date: 2013-11-28

Abstract

This optical element is provided with: a wavelength conversion member comprising a first region and a second region that have differing concentrations of a wavelength conversion material; and at least one heat dissipation member that is in contact with the wavelength conversion member. The concentration in the first region is higher than the concentration in the second region, and the heat dissipation member is in contact with the first region of the wavelength conversion member.

Description

Optical element, light emitting device, and projection device

The present invention relates to an optical element, a light emitting device, and a projection device, and particularly to an optical element having a wavelength conversion member, a light emitting device, and a projection device.

In lighting and projectors, light emitting devices with high brightness, low power consumption, and long life are required. Currently, there are light emitting devices that use light emitting diodes (Light Emitting Diodes; LEDs) or semiconductor lasers (Laser Diodes; LDs) as light emitting devices that satisfy this requirement.

LEDs and LDs are made of semiconductor materials. When an InGaN-based semiconductor material is used, the LED and the LD can generate blue light. When an AlGaInP-based semiconductor material is used, the LED and the LD can generate red light. However, LEDs and LDs using InGaN-based and AlGaInP-based materials have low green light emission efficiency. For this reason, many light-emitting devices which combined LED, LD, and the wavelength conversion member are proposed.

For example, in Patent Document 1, in response to a problem that the light extraction rate is reduced, an LED chip is mounted, and a wiring board for supplying power to the LED chip is formed around the LED chip mounting portion. There is disclosed a light emitting device having a concave opening formed and a wavelength conversion member in which a wavelength conversion material is contained in a translucent material.

In Patent Document 1, as the wavelength conversion member, a member in which the concentration of the wavelength conversion material increases toward the central portion, or a member in which the wavelength conversion material is settled on the side of the wavelength conversion member facing the LED chip is used. ing.

JP 2005-166733 A (paragraphs “0007”, “0024”, “0035” to “0038”, FIGS. 1, 8, and 9)

In the wavelength conversion member, generally, the more the wavelength conversion material is, the more light is wavelength-converted. Therefore, it is desirable that the concentration of the wavelength conversion material is higher. However, when light is wavelength-converted by the wavelength conversion material, heat is generated and the temperature of the wavelength conversion member rises. As in the wavelength conversion member described in Patent Document 1, when the concentration of the wavelength conversion material in the center of the wavelength conversion member and the region on the surface facing the LED chip is increased, the temperature of the wavelength conversion member starts from these regions. Rises.

When the temperature of the wavelength conversion member increases, the vibration energy of the wavelength conversion material increases, the proportion of excitation light that is not wavelength-converted by the wavelength conversion material increases, and the fluorescence intensity may decrease (temperature quenching). For this reason, it is desirable to prevent the temperature of the wavelength conversion member from rising as much as possible.

An object of the present invention is to provide an optical element, a light emitting device, and a projection device that solve the above-described problem that the temperature of the wavelength conversion member increases.

In order to achieve the above object, an optical element according to the present invention includes a wavelength conversion member having a first region and a second region having different concentrations of the wavelength conversion material, and at least one heat radiating member in contact with the wavelength conversion member. The concentration of the first region is higher than that of the second region, and the heat dissipation member is in contact with the first region of the wavelength conversion member.

The light-emitting device of the present invention includes the optical element of the present invention and a light source that emits light incident on the wavelength conversion member.

The projection device of the present invention includes the light emitting device of the present invention and a projection optical system that projects light emitted from the light emitting device.

According to the present invention, an increase in the temperature of the wavelength conversion member can be suppressed.

It is a perspective view which shows the optical element of the 1st Embodiment of this invention. 1A is a plan view and FIG. 2B is a cross-sectional view of 2B-2B showing an optical element according to a first embodiment of the present invention. FIG. 2B is a cross-sectional view of the optical element according to the first embodiment of the present invention, taken along the line (A) 2B-2B, showing the concentration distribution in the xz direction of the wavelength conversion material of the wavelength conversion member, and (B) 3B. FIG. 3C is a cross-sectional view of −3B, showing a concentration distribution in the yz direction. It is a figure and graph which show the density distribution in the xz direction of the wavelength conversion material which another example of the wavelength conversion member which the optical element of the 1st Embodiment of this invention has has. It is sectional drawing which shows another example of the optical element of the 1st Embodiment of this invention. The example in which the wavelength conversion member and the heat dissipation member of the optical element of the first embodiment of the present invention are (A) fitted, (B) another example to be fitted, and (C) yet another example to be fitted. FIG. It is a graph which shows the relationship between the density | concentration of a wavelength conversion material, and the light quantity of the fluorescence radiate | emitted from a wavelength conversion member. It is a graph which shows the relationship between the density | concentration of a wavelength conversion material, and the transmittance | permeability with respect to fluorescence. It is a perspective view which shows the optical element of the 2nd Embodiment of this invention. FIG. 6A is a plan view, FIG. 10B-10B sectional view, and FIG. 11C-11B-11B sectional view showing an optical element according to a second embodiment of the present invention. (A) 10B-10B cross-sectional view of the optical element of the second embodiment of the present invention, a diagram and graph showing the concentration distribution in the xz direction of the wavelength conversion material possessed by the wavelength conversion member, and (B) 11B FIG. 11B is a cross-sectional view taken along the line -11B and shows a concentration distribution in the yz direction. It is a perspective view which shows the optical element of the 3rd Embodiment of this invention. It is (A) top view, (B) 13B-13B sectional view, and (C) 13C-13C sectional view showing an optical element of a third embodiment of the present invention. (A) 13B-13B cross-sectional view of the optical element of the third embodiment of the present invention, a diagram and graph showing the concentration distribution in the xz direction of the wavelength conversion material possessed by the wavelength conversion member, and (B) 13C FIGS. 13A and 13B are cross-sectional views and graphs showing concentration distribution in the yz direction. It is sectional drawing which shows another example of the optical element of the 3rd Embodiment of this invention. It is a figure which shows another example of the optical element of the 3rd Embodiment of this invention. It is sectional drawing which shows the optical element of the 4th Embodiment of this invention. It is sectional drawing which shows another example of the optical element of the 4th Embodiment of this invention. It is sectional drawing which shows the optical element of the 5th Embodiment of this invention. It is sectional drawing which shows the optical element of the 6th Embodiment of this invention. It is sectional drawing which shows the optical element of the 7th Embodiment of this invention. It is sectional drawing which shows the optical element of the 8th Embodiment of this invention. It is sectional drawing which shows the optical element of the 9th Embodiment of this invention. It is (A) perspective view and (B) top view which show the light-emitting device of the 10th Embodiment of this invention. It is 24B-24B sectional drawing of the light-emitting device of the 10th Embodiment of this invention. It is a figure which shows the projection apparatus of the 11th Embodiment of this invention.

(First embodiment)
FIG. 1 is a perspective view showing an optical element according to the first embodiment. As shown in FIG. 1, the optical element 108 includes a wavelength conversion member 104 and at least one heat radiating member 105 in contact with the wavelength conversion member 104. Details of the optical element 108 will be described with reference to FIGS. FIG. 2A is a plan view of the optical element 108. FIG. 2B is a cross-sectional view of the optical element 108. In FIG. 2B, the concentration of the wavelength conversion material in the wavelength conversion member 104 is represented by the darkness of the filled color. The darker the color, the higher the concentration, and the lighter the color, the lower the concentration. .

As shown in FIG. 2B, the wavelength conversion member 104 has at least a first region 114 and a second region 113 having different concentrations of the wavelength conversion material, and the concentration of the first region 114 is the second concentration. The density of the region 113 is higher. One end side of the wavelength conversion member 104 is in contact with the heat dissipation member 105, and the other end side of the wavelength conversion member 104 is exposed. The first region 114 is disposed on the side of the wavelength conversion member 104 that contacts the heat dissipation member 105.

Next, the function of the optical element 108 will be described with reference to FIG. In the following description, light incident on the wavelength conversion member 104 is referred to as excitation light. In addition, the light whose wavelength is converted by the wavelength conversion member 104 is called fluorescence.

In the optical element 108, the wavelength conversion member 104 has a first region 114 and a second region 113 in which the concentration of the wavelength conversion material is different. The optical element 108 has an incident surface on which light is incident, and the first region and the second region are arranged in parallel in parallel to the surface direction of the incident surface. In FIG. 2B, the incident surface is a flat surface extending in the xy direction, and the first region and the second region are arranged in parallel in the x direction.

The concentration of the first region 114 is higher than the concentration of the second region 113. For this reason, the amount of light that is wavelength-converted in the first region 114 is larger than the amount of light that is wavelength-converted in the second region 113, and when the light is wavelength-converted in the first region 114. The heat that is generated increases. However, since the first region 114 is in contact with the heat dissipation member 105, the heat generated in the first region 114 is transmitted to the heat dissipation member 105 and is dissipated from the heat dissipation member 105. Therefore, in the optical element 108, it can suppress that the temperature of wavelength conversion member 104 itself raises, and can prevent that temperature quenching occurs.

In the present embodiment, an example of an optical element having one heat radiating member in contact with the wavelength conversion member is shown, but the number of heat radiating members is not limited to this.

Here, as illustrated in FIG. 2B, the wavelength conversion member 104 has a concentration of the wavelength conversion material lower than that of the first region 114 and a concentration of the wavelength conversion material higher than that of the second region 113. The region 115 may be provided. The third region 115 is disposed between the first region 114 and the second region of the wavelength conversion member 104.

FIG. 3A shows the concentration distribution of the wavelength conversion material in the x direction of the wavelength conversion member 104, and FIG. 3B shows the concentration distribution of the wavelength conversion material in the y direction of the wavelength conversion member 104. As shown in FIG. 3A, the concentration of the wavelength conversion material in the wavelength conversion member 104 continuously changes in the x direction, and the concentration is higher as it is closer to the heat dissipation member 105, and the concentration is higher as it is farther from the heat dissipation member 105. Is thin. On the other hand, as shown in FIG. 3B, the concentration of the wavelength conversion material in the y direction in the wavelength conversion member 104 is constant.

Thus, by changing the concentration in the wavelength conversion member 104, the concentration of the wavelength conversion material can be increased while preventing the temperature of the wavelength conversion member from rising.

The concentration distribution of the wavelength conversion material in the wavelength conversion member is not limited to that shown in FIGS. 3 (A) and 3 (B). For example, as shown in FIG. 4, the concentration of the wavelength conversion material in the wavelength conversion member 104a may change stepwise.

Here, the concentration of the wavelength conversion material is expressed in wt% and is obtained by (weight of wavelength conversion material) / (weight of wavelength conversion member). When the wavelength conversion member is composed of a wavelength conversion material and a binder, the concentration of the wavelength conversion material is obtained by (weight of wavelength conversion material) / (weight of binder + weight of wavelength conversion material).

The concentration of the wavelength conversion material is preferably 5 wt% or more, particularly 20 wt% or more. The concentration of the wavelength conversion material is desirably 50 wt% or less, particularly 40 wt% or less. For example, the concentration of the first region can be 30 wt% or more and 50 wt% or less, and the concentration of the second region can be 5 wt% or more and less than 30 wt%. The concentration of the wavelength conversion material is desirably determined in consideration of the excitation light absorption rate of the wavelength conversion material, the thickness of the wavelength conversion member, and the like. Moreover, when the wavelength conversion member has a binder, it is desirable to determine in consideration of the thermal conductivity of the binder.

The wavelength conversion member 104 may have a binder that maintains a state in which the wavelength conversion material is dispersed. The binder is preferably made of glass or transparent resin.

In addition, when the temperature of the wavelength conversion member 104 rises, not only the temperature quenching but also the structural stability of the wavelength conversion member 104 is lowered. For example, when glass is used for the binder of the wavelength conversion member 104, the wavelength conversion member 104 may be cracked due to melting of the glass or heat-induced mechanical stress. Further, when a resin is used for the binder, a decrease in transmittance due to the modification of the resin, a thermal deformation of the resin, or the like occurs. On the other hand, in the optical element 108 of this embodiment, since the temperature rise of the wavelength conversion member 104 can be suppressed, these problems can be prevented from occurring.

Fluorescent material is used for the wavelength conversion material used in this embodiment. The heat radiating member used in the present embodiment has a thermal conductivity higher than that of air.

Further, in order to release the heat generated in the wavelength conversion member through the heat dissipation member, it is desirable that the heat conductivity of the heat dissipation member is large, and in particular, it is desirable that it is larger than the binder of the wavelength conversion member. For example, the heat dissipation member desirably contains a metal material such as copper or aluminum. The thermal conductivity of metal materials is large. For this reason, the heat generated in the wavelength conversion member can be efficiently released by including a metal material in the heat dissipation member.

The heat dissipation member may contain a resin material. When the heat radiating member contains the resin material, the adhesion between the heat radiating member and the wavelength conversion member is improved, and heat generated by the wavelength conversion member is easily transmitted to the heat radiating member. Therefore, for example, as shown in FIG. 5, a heat radiating member 105e containing a resin material may be provided in contact with the wavelength conversion member 104e. In this case, since the thermal conductivity of the resin material is not generally high, it is desirable to further provide another heat radiating member 106e having a high thermal conductivity in contact with the heat radiating member 105e.

Further, the heat radiating member may be either a heat sink or a heat pipe. Since heat sinks and heat pipes have high thermal conductivity and a large heat dissipation effect, it is possible to dissipate heat generated by the wavelength conversion member.

It is desirable that the heat dissipating member has a reflecting surface that reflects light on the surface in contact with the wavelength converting member. By making the surface of the heat radiating member in contact with the wavelength conversion member a reflective surface, light emitted from the surface of the wavelength conversion member in contact with the heat radiating member can be returned to the wavelength conversion member, and light absorption loss in the heat radiating member occurs. Can be prevented.

The method for contacting the wavelength conversion member and the heat dissipation member is not particularly limited. For example, as shown in FIG. 6A, a convex structure and a concave structure may be provided on each of the wavelength conversion member 104b and the heat dissipation member 105b, and the convex structure and the concave structure may be fitted. As described above, by providing the concave-convex structure and fitting, the area where the wavelength conversion member 104b and the heat dissipation member 105b are in contact with each other is increased. As a result, heat generated in the wavelength conversion member 104b is easily transmitted to the heat dissipation member 105b. 6A shows an example in which the wavelength conversion member 104b has a convex structure and the heat dissipation member 105b has a concave structure. However, the wavelength conversion member has a concave structure and the heat dissipation member has a convex structure. It may have.

FIG. 6B shows another example in which the wavelength conversion member and the heat dissipation member are fitted. The thickness of the heat radiating member 105c is thicker than the thickness of the wavelength conversion member 104c. Furthermore, only the heat radiating member 105c has a concave structure. Thus, by providing the heat dissipation member 105c with a concave structure and fitting the concave structure with the wavelength conversion member 104c, the area where the wavelength conversion member 104c and the heat dissipation member 105c are in contact with each other increases. As a result, heat generated in the wavelength conversion member 104c is easily transmitted to the heat dissipation member 105c. FIG. 6B shows an example in which only the heat radiating member 105c has a concave structure, but only the wavelength conversion member may have a concave structure.

FIG. 6C shows still another example in which the wavelength conversion member and the heat dissipation member are fitted. Here, the heat radiating member 105d is provided with counterbore, and the end of the heat radiating member 105d has a step structure. As described above, by providing the heat dissipation member 105d with a step structure and fitting the step structure with the wavelength conversion member 104d, the area where the wavelength conversion member 104d and the heat dissipation member 105d are in contact with each other increases. As a result, heat generated in the wavelength conversion member 104d is easily transmitted to the heat dissipation member 105d. FIG. 6C shows an example in which only the heat radiating member 105d has a stepped structure, but only the wavelength conversion member may have a stepped structure.

As shown in FIGS. 6A to 6C, by fitting the wavelength conversion member and the heat dissipation member, the contact surface between the wavelength conversion member and the heat dissipation member is less likely to be displaced. And a more stable structure. For this reason, the assembly of the optical element and the light emitting device is facilitated, and the reliability of the optical element as a vibration is improved.

The concentration of the wavelength conversion material in the wavelength conversion member is preferably determined in consideration of the amount of fluorescence extracted from the emission surface of the wavelength conversion member and the ratio (transmittance) of the fluorescence transmitted through the wavelength conversion member. Hereinafter, the relationship between the concentration of the wavelength conversion material and the amount of fluorescence extracted from the emission surface, and the relationship between the concentration of the wavelength conversion material and the transmittance for fluorescence will be described.

As shown in FIG. 2B, the excitation light 110 that has entered the wavelength conversion member 104 is absorbed by the wavelength conversion material included in the wavelength conversion member 104, and is emitted from the wavelength conversion member 104 as

fluorescence

111 and 112. . The fluorescence includes fluorescence 112 emitted from the incident surface on the side where the excitation light 110 is incident and fluorescence 111 emitted from the emission surface opposite to the incident side. Since the fluorescence 111 is usually used in the projection apparatus, it is preferable that the amount of the fluorescence 111 is large. Here, the surface of the wavelength conversion member 104 on which the excitation light 110 is incident is referred to as an incident surface, and the side opposite to the incident side is referred to as an emission surface.

FIG. 7 is a graph showing the relationship between the concentration of the wavelength conversion material and the amount of fluorescence. The dotted line in the graph indicates the total amount of fluorescence when the amount of excitation light 110 is constant. On the other hand, the solid line indicates the amount of fluorescence 111 emitted from the emission surface of the wavelength conversion member 104 out of the total amount of fluorescence.

As shown in FIG. 7, the total amount of fluorescent light increases as the concentration of the wavelength conversion material increases. On the other hand, the light quantity of the fluorescence 111 emitted from the wavelength conversion member 104 becomes maximum at a certain concentration Do. This is because, as shown in FIG. 8, when the concentration of the wavelength conversion material is increased, the ratio of the fluorescence transmitted through the wavelength conversion member 104 is reduced.

Therefore, in order to maximize the amount of fluorescence 111 emitted from the emission surface of the wavelength conversion member 104, it is desirable to set the concentration of the wavelength conversion material to the concentration Do.

In the case of the optical element of the present embodiment, the amount of the fluorescence 111 emitted from the wavelength conversion member 104 can be maximized by setting the concentration of the first region of the wavelength conversion member 104 in contact with the heat dissipation member 105 to the concentration Do.

On the other hand, the concentration of the second region 113 of the wavelength conversion member 104 that is not in contact with the heat dissipation member 105 is set lower than the concentration Do in order to prevent the temperature from rising.

Next, a method for manufacturing the wavelength conversion member will be described. For example, when glass is used as the binder, the wavelength conversion member can be produced by mixing glass powder and wavelength conversion material powder and sintering the mixed powder. When a resin is used as the binder, the wavelength conversion member can be produced by mixing the powder of the wavelength conversion material with the resin softened by heating.

The concentration distribution of the wavelength conversion material in the wavelength conversion member is provided by adjusting the ratio of mixing the wavelength conversion member and the binder. The wavelength conversion member can also be produced by laminating or arranging layers having a constant concentration of the wavelength conversion material.

(Second Embodiment)
An optical element according to the second embodiment of the present invention will be described. FIG. 9 is a perspective view showing an optical element 208 according to the second embodiment of the present invention. The optical element 208 has a wavelength conversion member 204 and two heat radiating members 205 in contact therewith. The optical element 208 differs from the optical element 108 of the first embodiment in that it has two heat radiating members 205.

Details of the optical element 208 will be described with reference to FIGS. FIG. 10A is a plan view of the optical element 208. FIG. 10B is a cross-sectional view of the optical element 208.

As shown in FIG. 10B, the heat dissipating member 205 is provided at both ends of the wavelength converting member 204. The heat dissipating member 205 has first regions 214 at both ends thereof and a second region 213 at the center.

In the optical element 208, the heat radiating member 205 is provided at both ends of the wavelength conversion member 204. Further, the wavelength conversion member 204 has first regions 214 at both ends thereof and a second region 213 at the center. For this reason, while the amount of heat generated at the center of the wavelength conversion member 204 is reduced, the amount of heat generated at the end of the wavelength conversion member 204 is increased. However, the heat generated at the end of the wavelength conversion member 204 can be dissipated through the heat dissipation member 205 in contact with both ends of the wavelength conversion member. As a result, it is possible to prevent the temperature of the wavelength conversion member from rising while increasing the concentration of the wavelength conversion material contained in the wavelength conversion member 204 to increase the amount of fluorescence.

The concentration distribution of the wavelength conversion material in the x direction of the wavelength conversion member 204 is shown in FIG. 11A, and the concentration distribution of the wavelength conversion material in the y direction of the wavelength conversion member 204 is shown in FIG. As shown in FIG. 11A, the concentration of the wavelength conversion material in the wavelength conversion member 204 continuously changes in the x direction, and the concentration is higher as it is closer to the heat dissipation member 205, and the concentration is closer to the heat dissipation member 205. Is thinner. On the other hand, as shown in FIG. 11B, the concentration of the wavelength conversion material in the y direction in the wavelength conversion member 204 is constant. This is because the heat dissipation member 205 is not in contact with the y direction of the wavelength conversion member 204.

(Third embodiment)
An optical element according to the third embodiment of the present invention will be described. FIG. 12 is a perspective view showing an optical element 308 according to the third embodiment of the present invention. The optical element 308 includes a wavelength conversion member 304 and four heat radiating members 305 in contact therewith. The optical element 308 is different from the optical elements of the first and second embodiments in that it has four heat dissipating members 305.

Details of the optical element 308 will be described with reference to FIGS. FIG. 13A is a plan view showing the optical element 308. FIGS. 13B and 13C are cross-sectional views showing the optical element 308.

In the optical element 308, the heat dissipation member 305 is provided at the four ends of the wavelength conversion member. Further, as shown in FIGS. 13B and 13C, the wavelength conversion member 304 has a first region 314 at its four ends and a second region 313 at the center. For this reason, the amount of heat generated at the center of the wavelength conversion member 304 is reduced, while the amount of heat generated at the end of the wavelength conversion member 304 is increased. However, the heat generated at the ends of the wavelength conversion member 304 can be dissipated through the heat dissipating member 305 in contact with the four ends of the wavelength conversion member. As a result, it is possible to prevent the temperature of the wavelength conversion member from rising while increasing the concentration of the wavelength conversion material.

FIG. 14A shows the concentration distribution of the wavelength conversion material in the x direction of the wavelength conversion member 304, and FIG. 14B shows the concentration distribution of the wavelength conversion material in the y direction of the wavelength conversion member 304. As shown in FIG. 14A, the concentration of the wavelength conversion material in the wavelength conversion member 304 continuously changes in the x direction, and the concentration is higher as it is closer to the heat dissipation member 305 and the concentration is further away from the heat dissipation member 305. Is thinner. Similarly, as shown in FIG. 14B, the concentration of the wavelength conversion material in the wavelength conversion member 304 continuously changes in the y direction. The closer to the heat dissipation member 305, the higher the concentration. The farther away, the lower the concentration.

The shape of the heat dissipation member is not limited to that shown in FIG. For example, like the optical element 308a shown in FIG. 15, the single heat radiating member 305a may be contacted with four ends of the wavelength conversion member 304a. When the heat dissipating member 305a has such a structure, the number of parts for manufacturing the optical element can be reduced, and the manufacturing becomes easy.

Further, the shapes of the wavelength conversion member and the heat dissipation member are not limited to those shown in FIGS. For example, like the optical element 308b shown in FIG. 16, the wavelength conversion member 304b may have a disk shape. Further, the heat radiation member 305b may have a shape surrounding the wavelength conversion member 304b.

(Fourth embodiment)
The optical element of the 4th Embodiment of this invention is demonstrated. FIG. 17 is a sectional view showing an optical element 408 according to the fourth embodiment of the present invention. The optical element 408 has a wavelength conversion member 404 and two heat radiating members 405 in contact therewith. Furthermore, it has a transparent member 422 that faces the wavelength conversion member 404 and is provided in contact with the wavelength conversion member 404. The optical element 408 differs from the first to third embodiments in that it includes a transparent member 422.

The transparent member 422 is disposed in contact with each of the upper surface and the lower surface of the wavelength conversion member 404. By arranging the transparent member 422 in this way, the mechanical strength of the wavelength conversion member 404 can be increased. For this reason, for example, the wavelength conversion member can be thinned to increase the efficiency of wavelength conversion of the excitation light incident on the wavelength conversion member and output as fluorescence. For example, the thickness of the wavelength conversion member can be 1 mm or less. It becomes.

The thickness of the wavelength conversion member is desirably determined in consideration of the absorption rate of excitation light, the emission efficiency of fluorescence, the transmittance for fluorescence, and the like.

As the material of the transparent member 422, it is desirable to use a material having a high transmittance with respect to excitation light or fluorescence. As a material of the transparent member 422, for example, glass or transparent resin can be used.

FIG. 18 is a cross-sectional view of the optical element 408a when a material having a high thermal conductivity is used as the material of the transparent member 422. In the optical element 408a, the concentration of the wavelength conversion material increases from the center of the wavelength conversion member 404a toward the surface in contact with the heat dissipation member 405 and the surface in contact with the transparent member 422 of the wavelength conversion member 404a. Examples of the material of the transparent member 422 include sapphire and crystal having a higher thermal conductivity than glass or resin of a binder material.

In the optical element 408a, not only the heat radiating member 405 but also the transparent member 422 has a function of radiating heat generated by the wavelength converting member 404a. For this reason, it becomes possible to realize a larger heat dissipation effect.

17 and 18 show the optical element 408 in which the transparent member 422 is in contact with the upper surface and the lower surface of the wavelength conversion member, but the optical element of the present embodiment is not limited to this. For example, the optical element may include a transparent member that is in contact with only one of the upper surface and the lower surface of the wavelength conversion member.

(Fifth embodiment)
An optical element according to the fifth embodiment of the present invention will be described. FIG. 19 is a sectional view showing an optical element 508 according to the fifth embodiment of the present invention. The optical element 508 includes a wavelength conversion member 504 and two heat radiating members 505 in contact therewith. The heat dissipation member 505 is made of a transparent member. Further, in order to dissipate heat generated in the wavelength conversion member 504, a material having a higher thermal conductivity than the binder material included in the wavelength conversion member 504 is used as the material of the heat dissipation member 505. Examples of such materials include sapphire and quartz.

In the optical element 508, the heat radiating member 505 made of a transparent member is in contact with the upper surface and the lower surface of the wavelength conversion member 504. The upper and lower surfaces of the wavelength conversion member 504 have a larger area than the side surfaces. For this reason, in the optical element 508, the contact area between the heat dissipation member 505 and the wavelength conversion member 504 can be increased compared to the case where the heat dissipation member is in contact with the side surface, and the heat generated by the wavelength conversion member 504 can be generated faster. Can tell.

FIG. 19 shows the optical element 508 in which the heat dissipation member 505 is in contact with the upper surface and the lower surface of the wavelength conversion member 504, but the optical element of the present embodiment is not limited to this. For example, the optical element may have a heat radiating member that contacts only one of the upper surface and the lower surface of the wavelength conversion member.

(Sixth embodiment)
An optical element according to a sixth embodiment of the present invention will be described. FIG. 20 is a cross-sectional view showing an optical element 608 according to the sixth embodiment of the present invention. The optical element 608 has a wavelength conversion member 604 and two heat radiating members 605 in contact therewith. Furthermore, it has the wavelength selection filter 623 arrange | positioned facing the wavelength conversion member 604. FIG. The optical element 608 differs from the first to fifth embodiments in that it includes a wavelength selection filter 623.

The wavelength selection filter 623 has a characteristic of reflecting or absorbing the excitation light 610 and transmitting the fluorescence 611 generated by the wavelength conversion member 604.

Since the concentration of the wavelength conversion material of the wavelength conversion member 604 varies depending on the position, the light spectrum varies depending on the position of the light emitted from the wavelength conversion member 604. In addition, since the optical path length of the excitation light in the wavelength conversion member 604 varies depending on the incident angle to the wavelength conversion member 604, the light spectrum varies depending on the emission angle of the light transmitted through the wavelength conversion member 604. For this reason, color unevenness is likely to occur in the light emitted from the wavelength conversion member 604. However, by providing the wavelength selection filter 623 so as to face the wavelength conversion member 604, the light emitted from the optical element 608 can be only the fluorescence 611, and color unevenness can be reduced.

Also, the wavelength conversion member 604 has a region where the concentration of the wavelength conversion material is thin. Since the absorption rate of the excitation light 610 is low in this region, the proportion of the excitation light incident on the wavelength conversion member that is transmitted without being wavelength-converted increases. When the wavelength selection filter 623 having the characteristic of reflecting light in the wavelength band of the excitation light 610 is disposed, the excitation light 610 that has passed through the wavelength conversion member 604 is reflected by the wavelength selection filter 623 and is again converted into wavelength. Incident on the member 604. And since the excitation light 610 which entered again into the wavelength conversion member 604 is converted into the fluorescence 611, as a result, the light quantity of the fluorescence 611 can be enlarged.

The wavelength selection filter 623 has a characteristic of transmitting a specific wavelength band using a glass substrate containing a material that absorbs light in the wavelength band of excitation light, a dielectric multilayer film, a holographic element, a photonic crystal, or the like. Things can be used.

The wavelength selection filter 623 may be separated from the wavelength conversion member 604 or may be in contact with the wavelength conversion member 604.

(Seventh embodiment)
An optical element according to a seventh embodiment of the present invention will be described. FIG. 21 is a sectional view showing an optical element 708 according to the seventh embodiment of the present invention. The optical element 708 includes a wavelength conversion member 704 and two heat radiating members 705 in contact therewith. Furthermore, it has the wavelength selection filter 724 arrange | positioned facing the wavelength conversion member 704. FIG. The optical element 708 is different from the first to fifth embodiments in that it includes a wavelength selection filter 724.

The wavelength selection filter 724 has a characteristic of transmitting light in the wavelength band of the excitation light 710 and reflecting light in the wavelength band of the fluorescence 711 generated by the wavelength conversion member 704.

Since the fluorescence 711 emits isotropically in the wavelength conversion member 704, a part of the fluorescence 711 is emitted to the side on which the excitation light 710 is incident. In the optical element 708, the fluorescence 711 emitted to the incident side of the excitation light 710 is reflected by the wavelength selection filter 724 and emitted from the emission side of the wavelength conversion member 704. Thereby, the light quantity of the fluorescence 711 emitted from the emission surface of the wavelength conversion member 704 can be increased.

As the wavelength selection filter 724, a dielectric multilayer film, a holographic element, a photonic crystal, or the like that has a characteristic of transmitting a specific wavelength band and reflecting other light can be used.

(Eighth embodiment)
An optical element according to an eighth embodiment of the present invention will be described. FIG. 22 is a sectional view showing an optical element 808 according to the eighth embodiment of the present invention. The optical element 808 has a wavelength conversion member 804 and two heat radiating members 805 in contact therewith. Further, a polarizer 825 disposed to face the wavelength conversion member 804 is provided. The optical element 808 differs from the first to seventh embodiments in that it includes a polarizer 825.

The polarizer 825 transmits light having a polarization component parallel to the transmission axis of the polarizer 825 in the fluorescence 811 and reflects light having a polarization component parallel to the direction orthogonal to the transmission axis. For this reason, part of light having a polarization component parallel to the direction orthogonal to the transmission axis can be reflected by the polarizer 825, reflected by the wavelength conversion member 804, and incident again on the polarizer 825. As a result, light having a polarization component parallel to the transmission axis of the polarizer 825 can be efficiently extracted.

As the polarizer 825, a wire grid polarizer, a multilayer film using an organic material, or the like can be used.

The optical element 808 can be used for a projector using a liquid crystal panel as a display element. The liquid crystal panel has polarization dependency. Therefore, the projector spatially modulates only the light of the polarization component in a specific direction, and the light of the polarization component in the direction orthogonal to the specific direction is not modulated and used. Since the light emitted from the optical element 808 is linearly polarized light having a polarization component in a specific direction, the amount of light not used in the optical system as described above can be reduced, and the amount of light emitted from the projector can be improved.

(Ninth embodiment)
An optical element according to the ninth embodiment of the present invention will be described. FIG. 23 is a sectional view showing an optical element 908 according to the ninth embodiment of the present invention. The optical element 908 includes a wavelength conversion member 904 and two heat radiating members 905 in contact therewith. Further, the optical unit 926 is disposed to face the wavelength conversion member 904. The optical element 908 is different from the first to eighth embodiments in that it includes an optical unit 926.

As the optical unit 926, a rod integrator made of a columnar transparent material, a light pipe having a cylindrical shape and having a specular reflection inside the cylinder, a lens array in which a plurality of lenses are arranged in a plane, and the like are used. Can do.

The intensity distribution of the fluorescence 911 can be made uniform by the optical unit 926. For this reason, for example, when the optical element 908 is used in a projector, the intensity distribution of light emitted from the projector is made uniform. As a result, when light is projected from a projector onto a screen or the like, illuminance unevenness on the screen can be made uniform.

(Tenth embodiment)
A light emitting device according to a tenth embodiment of the present invention will be described. FIG. 24A is a perspective view showing a light emitting device 1001 according to the tenth embodiment of the present invention. The light emitting device 1001 includes an optical element 1008 and a light source 1002. The light source 1002 is disposed so that the light emitting surface thereof faces the wavelength conversion member 1004 of the optical element 1008 and light from the light source enters the wavelength conversion member 1004. The optical element 1008 is the same as that described in the third embodiment.

Details of the light-emitting device 1001 will be described with reference to FIGS. FIG. 24B is a plan view illustrating the light-emitting device 1001. FIG. 25 is a cross-sectional view illustrating the light emitting device 1001.

In the light emitting device 1001, it is possible to take out the fluorescence 1011 by making the light from the light source 1002 incident on the wavelength conversion member 1004 as the excitation light 1010 while preventing the temperature of the wavelength conversion member 1004 from rising.

As the light source, for example, an LED or a semiconductor laser can be used, but it is not particularly limited thereto. Further, the shape of the light source is not limited. For example, the light source may be a surface-emitting solid-state light source or a surface-emitting device including a light source and a light guide plate.

In the light emitting device 1001, the optical element 1008 is described in the third embodiment, but the optical element 1008 is not limited to this. Any of the optical elements shown in the first to ninth embodiments can be used in the light emitting device. Further, the light-emitting device includes the wavelength selection filter 623 shown in the sixth embodiment, the wavelength selection filter 724 shown in the seventh embodiment, the polarizer 825 shown in the eighth embodiment, and the ninth embodiment. In addition, any two or more of the four elements of the optical unit 926 may be included. Further, an optical element such as a lens or a folding mirror may be provided in front of or behind each element.

Further, in a light emitting device having any two or more of the three elements of the wavelength selection filter 623, the polarizer 825, and the optical unit 926, basically, the three elements may be arranged in any order. . When the wavelength selection filter 623 shown in the sixth embodiment and the wavelength selection filter 724 shown in the seventh embodiment are provided, each wavelength selection filter may be arranged so as to sandwich the wavelength conversion member. desirable.

(Eleventh embodiment)
An embodiment in which the light emitting device of the present invention is applied to a projection device will be described. FIG. 26 shows a configuration diagram of a projector as the projection apparatus of this embodiment. The projector 1129 includes light emitting

devices

1101a, 1101b, and 1101c,

liquid crystal panels

1127a, 1127b, and 1127c, a cross dichroic prism 1128, and a projection optical system 1130b. Here, the

light emitting devices

1101a, 1101b, and 1101c may be any of the light emitting devices described in the tenth embodiment.

Each of the

light emitting devices

1101a, 1101b, and 1101c emits light having different wavelengths. For example, red light is emitted from the light emitting device 1101a, green light is emitted from the light emitting device 1101b, and blue light is emitted from the light emitting device 1101c.

Light emitted from each of the

light emitting devices

1101a, 1101b, and 1101c is incident on each of the

liquid crystal panels

1127a, 1127b, and 1127c. The

liquid crystal panels

1127a, 1127b, and 1127c two-dimensionally modulate each incident color light according to a video signal so that each color light carries an image, and spatial light that emits each color light carrying the image. It is a modulation element. Although a liquid crystal panel is used as the spatial light modulation element here, the spatial light modulation element may be a digital micromirror device.

The cross dichroic prism 1128 synthesizes and outputs the modulated lights emitted from the

liquid crystal panels

1127a, 1127b, and 1127c.

The projection optical system 1130b projects the combined light emitted from the cross dichroic prism 1128 onto the screen 1130a, and displays an image corresponding to the video signal on the screen 1130a.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and it is also included within the scope of the present invention. Not too long.

Some or all of the above embodiments can be described as in the following supplementary notes, but are not limited thereto.

(Additional remark 1) It has a wavelength conversion member and at least 1 heat dissipation member which touches the said wavelength conversion member, and the said wavelength conversion member is a 1st area | region from which the density | concentration of the wavelength conversion material contained in the said wavelength conversion member differs. An optical element having a second region, wherein the concentration of the first region is higher than that of the second region, and a surface of the wavelength conversion member in contact with the heat dissipation member is formed of the first region.

(Supplementary note 2) The optical element according to supplementary note 1, wherein the heat dissipation member is disposed in contact with one end of the wavelength conversion member, and the other end of the wavelength conversion member is exposed.

(Supplementary note 3) The optical element according to supplementary note 1, wherein the heat radiation member has two heat radiation members, and the heat radiation member is provided at both ends of the wavelength conversion member.

(Supplementary note 4) The optical element according to supplementary note 1, wherein the heat dissipation member has four, and the heat dissipation member is provided at four ends of the wavelength conversion member.

(Supplementary Note 5) The wavelength conversion member has the third region where the concentration of the wavelength conversion material is lower than that of the first region, and the concentration of the wavelength conversion material is higher than that of the second region. The optical element according to any one of appendices 1 to 4, wherein the third region is disposed between the first region and the second region.

(Additional remark 6) The density | concentration of the said wavelength conversion material of the said 1st area | region and the density | concentration of the said wavelength conversion material of the said 2nd area | region are 5 wt% or more and 50 wt% or less in any one of Additional remarks 1-5 Optical element.

(Supplementary note 7) The concentration of the wavelength conversion material in the first region is 30 wt% or more and 50 wt% or less, and the concentration of the wavelength conversion material in the second region is 5 wt% or more and less than 30 wt%. 7. The optical element according to 6.

(Appendix 8) The optical element according to any one of appendices 1 to 7, wherein the wavelength conversion member includes a binder that maintains a state in which the wavelength conversion material is dispersed.

(Supplementary note 9) The optical element according to any one of supplementary note 8, wherein the thermal conductivity of the heat radiating member is larger than the thermal conductivity of the binder.

(Appendix 10) The optical element according to any one of appendices 1 to 9, wherein the wavelength conversion material is a phosphor.

(Additional remark 11) The said heat radiating member contains the area | region with high adhesiveness with the said wavelength conversion member, and the area | region with high heat conductivity, and the high adhesiveness area | region contacts the said wavelength conversion member. An optical element according to any one of the above.

(Supplementary note 12) The optical element according to supplementary note 11, wherein a resin material is contained in the region having high adhesion, and a metal material is contained in the region having high thermal conductivity.

(Appendix 13) The optical element according to any one of appendices 1 to 12, wherein the heat dissipating member is either a heat sink or a heat pipe.

(Appendix 14) The optical element according to any one of appendices 1 to 13, wherein the heat radiating member has a reflective surface that reflects light on a surface in contact with the wavelength conversion member.

(Supplementary note 15) The optical element according to any one of supplementary notes 1 to 14, wherein the heat dissipation member is made of a transparent material.

(Appendix 16) The optical element according to any one of appendices 1 to 15, wherein a concave structure is provided in at least one of the portions where the wavelength conversion member and the heat dissipation member are in contact with each other.

(Supplementary note 17) The optical element according to any one of supplementary notes 1 to 15, wherein a step structure is provided in at least one of the portions where the wavelength conversion member and the heat dissipation member are in contact with each other.

(Appendix 18) The wavelength conversion material has a function of emitting light in the second wavelength band when light in the first wavelength band is incident, and further reflects the light in the first wavelength band. An optical element according to any one of appendices 1 to 17, further comprising a first wavelength selection filter that transmits light in the wavelength band of the first wavelength selection filter, wherein the first wavelength selection filter is disposed to face the wavelength conversion member. .

(Additional remark 19) Furthermore, it has the 2nd wavelength selection filter which reflects the light of the said 2nd wavelength band, and permeate | transmits the light of the 1st wavelength band, The said 2nd wavelength selection filter is the said wavelength conversion The optical element according to appendix 18, wherein the optical element is disposed so as to face the member and to position the wavelength conversion member between the first wavelength selection filter and the second wavelength selection filter.

(Supplementary note 20) The wavelength conversion material has a function of emitting light in the second wavelength band when light in the first wavelength band is incident, and further reflects light in the second wavelength band. The optical device according to any one of appendices 1 to 17, further comprising: a second wavelength selection filter that transmits light in one wavelength band, wherein the second wavelength selection filter is disposed to face the wavelength conversion member. element.

(Additional remark 21) Furthermore, it has the polarizer which permeate | transmits the light of the polarization component of a specific direction, and reflects the polarization component of the direction different from the said specific direction, The said polarizer is arrange | positioned facing the said wavelength conversion member 21. The optical element according to any one of appendices 1 to 20.

(Supplementary note 22) The optical element according to any one of supplementary notes 1 to 21, further comprising an optical unit that uniformizes an intensity distribution of incident light, wherein the optical unit is disposed to face the wavelength conversion member.

(Supplementary note 23) A light-emitting device comprising the optical element according to any one of supplementary notes 1 to 22 and a light source that emits light incident on the wavelength conversion member.

(Appendix 24) The light emitting device according to appendix 23, wherein the light source is disposed to face the wavelength conversion member.

(Supplementary note 25) A projection device comprising the light emitting device according to supplementary note 23 or 24 and a projection optical system that projects light emitted from the light emitting device.

The invention of the present application is not limited to the above-described embodiment, and any design change or the like within a range not departing from the gist of the invention is included in the invention. In addition, this application claims priority based on Japanese Patent Application No. 2012-199979 filed on May 25, 2012, the entire disclosure of which is incorporated herein.

It can be widely applied to a projection device using a light emitting device.

1001, 1101a, 1101b, 1101c Light emitting device 1002

Light source

104, 104a, 104b, 104c, 104d, 104e, 204, 304, 304a, 304b, 404, 404a, 504, 604, 704, 804, 904, 1004 Wavelength conversion member 105 105a, 105b, 105c, 105d, 105e, 205, 305, 305a, 305b, 405, 505, 605, 705, 805, 905, 1005 Heat dissipation member 106e

Heat dissipation member

108, 208, 308, 308a, 308b, 408, 408a , 608, 708

Optical element

110, 610, 710, 810, 910, 1010

Excitation light

111, 611, 711, 811, 911, 1011

Fluorescence

112, 1012

Fluorescence

113, 213, 313

Second Region

114, 214, 314 First region 115 Third region 422 Transparent member 623 Wavelength selection filter 724 Wavelength selection filter 825 Polarizer 926

Optical unit

1127a, 1127b, 1127c Liquid crystal panel 1128 Cross dichroic prism 1129 Projector 1130a Screen 1130b Projection optical system

Claims

A wavelength conversion member having a first region and a second region having different concentrations of the wavelength conversion material;
At least one heat dissipating member in contact with the wavelength converting member;
With
The concentration of the first region is higher than that of the second region,
The optical element, wherein the heat dissipation member is in contact with the first region of the wavelength conversion member.
The optical element according to claim 1, wherein a side of the wavelength conversion member on which the second region is disposed is exposed.
The first region is disposed in an end region of the wavelength conversion member, and the second region is disposed in a central region;
The optical element according to claim 1, wherein the heat dissipation member is in contact with an end region of the wavelength conversion member.
Having two heat dissipating members,
The wavelength conversion member is a long body in which two first regions are disposed at both ends, and the second region is disposed between the two first regions,
The optical element according to claim 3, wherein the two heat radiating members are in contact with two first regions of the wavelength conversion member, respectively.
The wavelength conversion member has an incident surface on which light is incident,
The first region and the second region are arranged in parallel in the plane direction of the incident surface,
The optical element according to claim 1.
6. The optical element according to claim 1, wherein the concentration of the wavelength conversion material in the first region continuously decreases from the side in contact with the heat radiating member toward the second region.
7. The optical element according to claim 1, wherein a concentration of the wavelength conversion material in the first region and a concentration of the wavelength conversion material in the second region are 5 wt% or more and 50 wt% or less.
8. The optical element according to claim 1, wherein one of the wavelength conversion member and the heat dissipation member has a recess, and the wavelength conversion member and the heat dissipation member are fitted by the recess.
An optical element according to any one of claims 1 to 8,
A light source that emits light incident on the wavelength conversion member;
A light emitting device.
A light emitting device according to claim 9;
A projection optical system for projecting light emitted from the light emitting device;
A projection apparatus.