JP6912737B2 - Optical parts and manufacturing method of optical parts - Google Patents

Description

The present invention relates to an optical component and a method for manufacturing the optical component.

In the optical component described in Patent Document 1, a light-transmitting member is fixed to a light-extracting member such as alumina via a metal film (see, for example, FIG. 2 of Patent Document 1).

JP 2015-019013

The brightness of such an optical component may decrease due to deterioration of the metal film.

An optical component according to an embodiment of the present invention includes a light-transmitting member having an upper surface, a lower surface, and a side surface, and a light-reflecting member provided on the side of the light-transmitting member so as to surround the light-transmitting member. The light-reflecting member is made of ceramics containing a plurality of voids, and the plurality of voids are unevenly distributed in the vicinity of the light-transmitting member in one cross section crossing the light-transmitting member and the light-reflecting member.

A method for manufacturing an optical component according to an embodiment of the present invention includes a step of preparing a light-transmitting member having an upper surface, a lower surface, and a side surface, and an inorganic material on the side of the light-transmitting member so as to surround the light-transmitting member. The step of forming a molded body containing the light-reflecting powder, and the light-reflecting member containing the sintered body of the light-reflecting powder and the light-transmitting member are integrally formed and cross the light-transmitting member and the light-reflecting member. In one cross section, the light reflecting member includes a step of sintering the molded body so that a plurality of voids are unevenly distributed in the vicinity of the light transmitting member.

According to the above-mentioned optical component, it is possible to obtain an optical component that reduces a decrease in brightness and secures strength.

Further, according to the above-mentioned method for manufacturing an optical component, it is possible to easily manufacture an optical component that reduces a decrease in brightness and secures strength.

FIG. 1A is a top view of the optical component according to the first embodiment. FIG. 1B is a cross-sectional view taken along the line 1B-1B of FIG. 1A. FIG. 2A is a diagram for explaining a method of manufacturing an optical component according to the first embodiment. FIG. 2B is a cross-sectional view taken along the line 2B-2B of FIG. 2A. FIG. 3A is a diagram for explaining a method of manufacturing an optical component according to the first embodiment. FIG. 3B is a cross-sectional view taken along the line 3B-3B of FIG. 3A. FIG. 4A is a diagram for explaining a method of manufacturing an optical component according to the first embodiment. FIG. 4B is a cross-sectional view taken along the line 4B-4B of FIG. 4A. FIG. 5A is a diagram for explaining a method of manufacturing an optical component according to the first embodiment. FIG. 5B is a cross-sectional view taken along the line 5B-5B of FIG. 5A. FIG. 6A is a diagram for explaining a method of manufacturing an optical component according to the first embodiment. FIG. 6B is a cross-sectional view taken along the line 6B-6B of FIG. 6A. FIG. 7A is a diagram for explaining a method of manufacturing an optical component according to the first embodiment. FIG. 7B is a cross-sectional view taken along the line 7B-7B of FIG. 7A. FIG. 8A is a secondary electron image of the optical component observed from the upper surface side. FIG. 8B is an SEM image in the A region of FIG. 8A. FIG. 8C is an SEM image in region B of FIG. 8A. FIG. 9 is a diagram of a light emitting device in which the optical component and the light emitting element according to the second embodiment are combined. FIG. 10A is a top view of a light emitting device in which the optical component and the light emitting element according to the third embodiment are combined. FIG. 10B is a cross-sectional view taken along the line 10B-10B of FIG. 10A. FIG. 11 is a photograph of the optical component according to the embodiment observed from the upper surface side.

A mode for carrying out the present invention will be described below with reference to the drawings. However, the forms shown below are for embodying the technical idea of the present invention and do not limit the present invention. The size and positional relationship of the members shown in each drawing may be exaggerated to clarify the explanation.

<First Embodiment>
FIG. 1A shows a top view of the optical component 10 according to the first embodiment. Further, FIG. 1B is a cross-sectional view taken along the line 1B-1B of FIG. 1A.

The optical component 10 includes a light-transmitting member 1 having an upper surface, a lower surface, and a side surface, and a light-reflecting member 2 provided on the side of the light-transmitting member 1 so as to surround the light-transmitting member 1. The light reflecting member 2 is made of ceramics containing a plurality of voids, and the plurality of voids are unevenly distributed in the vicinity of the light transmitting member 1 in one cross section crossing the light transmitting member 1 and the light reflecting member 2.

According to the optical component 10, the optical component 10 can reduce the transmittance of the light reflecting member 2 and secure the strength. This point will be described below.

In the conventional optical component, a metal film is provided between the light transmitting member and the light extraction member, and the light directed from the light transmitting member to the light extraction member is reflected by the metal film and extracted. However, for example, when the vehicle is mounted on a vehicle, the metal film may be deteriorated due to salt damage or the like due to the vehicle being arranged in the coastal area. In this case, the light extraction efficiency is reduced. Therefore, it is conceivable to provide a light reflecting member made of ceramics around the light transmitting member without using a metal film. In this case, in order to suppress the transmission of light from the light-transmitting member to the light-reflecting member and efficiently reflect the light, it is conceivable to increase the pore ratio of the light-reflecting member, but the overall pore ratio is high. Then, the strength of the light reflecting member decreases.

Therefore, the inventor of the present application uses ceramics as the light-reflecting member 2 in which a plurality of voids are unevenly distributed in the vicinity of the light-transmitting member 1 in one cross section that crosses the light-transmitting member 1 and the light-reflecting member 2. That is, as the light reflecting member 2, the first region 2a of the first porosity and the second region 2b of the second porosity having a porosity lower than the first porosity are arranged in this order from the side closer to the translucent member 1. Ceramics with As a result, it is possible to secure the strength of the optical component 10 in the second region 2b while reducing the transmission of light from the light transmitting member 1 in the first region 2a. Therefore, it is possible to obtain the optical component 10 which reduces the decrease in brightness and secures the strength.

Hereinafter, the components of the optical component 10 will be described.

(Translucent member 1)
The light transmitting member 1 is made of a material that transmits light from a light emitting element or the like. As the light transmitting member 1, a material that does not melt at the sintering temperature of the light reflecting member 2 can be used. In the present embodiment, ceramics containing a phosphor (hereinafter, referred to as “fluorescent ceramics”) are used as the translucent member 1. In fluorescent ceramics, light is likely to be scattered inside the ceramics, so that the light reflecting member 2 is easily exposed to light. Therefore, the effect of suppressing the transmission of light in the first region 2a becomes more remarkable. Further, among the light reflecting members 2, the second region 2b having a low porosity has excellent heat dissipation as compared with the first region 2a having a high porosity. Therefore, the heat generated by the phosphor can be effectively dissipated in the second region 2b via the first region 2a. Although the fluorescent ceramics are used as the translucent member 1 here, a single crystal of the fluorescent material may be used. Even in this case, according to the present embodiment, the heat from the phosphor can be efficiently dissipated to the second region 2b of the light reflecting member 2.

Although another light-transmitting member may be interposed between the light-transmitting member 1 and the light-reflecting member 2, in the present embodiment, the light-transmitting member 1 is in contact with the side surface of the light-reflecting member 2. .. That is, the light transmitting member 1 and the light reflecting member 2 are in direct contact with each other without interposing other members. As a result, the light is not absorbed by other members, so that the light extraction efficiency is improved. Further, when the translucent member 1 contains a phosphor, the heat generated by the phosphor can be easily dissipated as compared with the case where the translucent member 1 is used through the other members.

In the present embodiment, as the fluorescent ceramics, those containing a fluorescent material and a binder made of an inorganic material are used. Specifically, a YAG (Yttrium Aluminum Garnet) -based phosphor is used as the phosphor, and aluminum oxide is used as the binder. Further, as the light reflecting member 2, a material containing aluminum oxide as a main component is used.
As described above, when the binder contained in the light transmitting member 1 contains the same material as the light reflecting member 2, the adhesion between the light transmitting member 1 and the light reflecting member 2 can be increased.

As the phosphor, it is preferable to use a phosphor having a linear expansion coefficient close to the linear expansion coefficient of the light reflecting member 2 in order to increase the adhesion between the light transmitting member 1 and the light reflecting member 2. When a material containing aluminum oxide as a main component is used as the light reflecting member 2, a YAG-based phosphor can be mentioned as a phosphor having a linear expansion coefficient close to this. The YAG-based phosphor also includes, for example, one in which at least a part of Y is replaced with Tb and one in which at least a part of Y is replaced with Lu. Further, the YAG-based phosphor may contain Gd, Ga or the like in the composition. When a YAG-based phosphor is used as the phosphor and aluminum oxide is used as the light reflecting member 2, the binder contained in the light transmitting member 1 is preferably aluminum oxide for the same reason. As the binder, for example, YAG and yttrium oxide that do not contain an activator can be used. By including the binder, the content of the phosphor can be adjusted, so that the color of the light emitted from the translucent member 1 can be easily adjusted.

As the translucent member 1, sapphire, translucent alumina, quartz or the like that does not contain a phosphor can also be used. Even when the light transmitting member 1 does not contain a phosphor, the light scattered by the light transmitting member 1 can be efficiently reflected in the first region 2a of the light reflecting member 2, and the second light reflecting member 2 can be reflected. The strength of the optical component 10 can be secured in the region 2b.

In the present embodiment, the translucent member 1 is a quadrangular prism, and its upper surface is a rectangle long in one direction. In addition to this, a cylinder, a polygonal prism, a truncated cone, and a truncated cone can be used, and among them, a cylinder or a truncated cone is preferable. In the case of a cylinder or a truncated cone, the width of the first region 2a (the length of the portion where the straight line passing through the center of the translucent member 1 which is circular when viewed from the upper surface and the first region 2a overlap) is made constant. Since it can be brought closer, it is possible to easily reduce uneven light emission.

(Light reflecting member 2)
The light reflecting member 2 is provided on the side of the light transmitting member 1 so as to surround the light transmitting member 1. In other words, the light reflecting member 2 is provided with a through hole penetrating in the vertical direction, and the light transmitting member 1 is provided inside the through hole. The upper surface of the light transmitting member 1 and the lower surface of the light transmitting member 1 are exposed from the light reflecting member 2.

The light reflecting member 2 is made of ceramics containing a plurality of voids. In one cross section crossing the light transmitting member 1 and the light reflecting member 2, a plurality of voids are unevenly distributed in the vicinity of the light transmitting member 1. That is, it has a first region 2a having a first porosity and a second region 2b having a second porosity having a porosity lower than that of the first porosity, in order from the side closer to the translucent member 1. If the overall porosity of the light reflecting member is lowered, the intensity is increased but the transmittance is lowered. This is because the interface inside the light reflecting member 2 is reduced, so that the light incident on the inside of the light reflecting member 2 is easily propagated. Further, if the porosity of the entire light reflecting member is increased, the transmittance is lowered but the strength is lowered. On the other hand, in the present embodiment, the light is efficiently reflected in the vicinity of the translucent member 1 by providing the first region 2a having a relatively high porosity so as to be in contact with the translucent member 1. .. Further, on the outside of the first region 2a, the strength is improved and the heat dissipation is improved by providing the second region 2b having a relatively low porosity. In the present specification, the first region 2a and the second region 2b are in the same member and have the same composition. That is, what is joined to different members is not the first region 2a and the second region 2b in the present specification. As a result, peeling between the first region 2a and the second region 2b can be made less likely to occur than when different members are joined to each other.

In the entire circumference of the translucent member 1, the width of the first region 2a (the length of the portion where the straight line passing through the central portion of the optical component 10 and the first region 2a overlap when viewed from above) is the second region in the straight line. It is preferably narrower than the width of 2b (the length of the portion where the straight line passing through the central portion of the optical component 10 and the second region 2b overlap when viewed from above). Thereby, it is possible to easily secure the strength of the light reflecting member 2.

The width of the first region 2a is preferably set in the range of 50 μm or more and 300 μm or less, and more preferably set in the range of 100 μm or more and 250 μm or less. By setting the range in the range of 50 μm or more, it is possible to easily reduce the transmission of light directed to the light reflecting member 2. Further, by setting in the range of 300 μm or less, when a member containing a phosphor is used as the translucent member 1, the distance to the second region 2b having low porosity and high heat dissipation can be reduced. The heat from the phosphor can be easily dissipated.

It is preferable that the width of the first region 2a is constant over the entire circumference of the light transmitting member 1, but it may be different as in the present embodiment. As an example, when the optical component 10 is viewed from above, the outer shape of the light transmitting member 1 and the outer shape of the light reflecting member 2 are both rectangular, the central portions of both are coincident, and one constituent side of each is mutual. Assume that they are parallel. Here, the distance of the portion where the straight line (hereinafter referred to as “L1”) passing through the central portion of the translucent member 1 and perpendicular to one constituent side of the translucent member 1 and the first region 2a overlap is defined as “D1a”. , The distance of the portion where L1 and the second region 2b overlap is defined as "D1b", and the straight line (hereinafter referred to as "L2") passing through the central portion of the translucent member 1 and perpendicular to L1 and the first region 2a The distance between the overlapping portions is defined as "D2a", and the distance between the overlapping portions of L2 and the second region 2b is defined as "D2b". In this case, for example, if D1a is larger than D2a, it is preferable to make D1b larger than D2b. If the width of the first region 2a is large, the light is easily reflected in the first region 2a, but the intensity is likely to decrease. However, even in such a case, by increasing the width of the second region 2b located in the vicinity of the first region 2a having a large width, it is possible to suppress a decrease in the strength of the optical component 10.

As shown in FIG. 1B, it is preferable that the first region 2a is arranged from the upper end to the lower end of the side surface of the light transmitting member 1. As a result, it is possible to reduce the transmission of light over the entire side surface of the light transmitting member 1.

As the light reflecting member 2, for example, zirconium oxide or titanium oxide can be used in addition to aluminum oxide. Further, the light reflecting member 2 may contain an additive made of a material different from the main material. Additives include itrim oxide, zirconium oxide, boron nitride, lutetium oxide, and lanthanum oxide. According to these materials, the light transmittance of the light reflecting member 2 can be reduced.

As described above, the first region 2a has a high porosity, and the second region 2b has a low porosity. For example, by observing the optical component in a dark field using an epi-illumination microscope as described in Examples described later, a region having a high porosity (first region) and a region having a low porosity (second region) can be observed. You can tell. In addition, by observing the light reflecting member 2 with a scanning electron microscope, the difference in porosity can be grasped. In the light reflecting member 2, "a plurality of voids are unevenly distributed on the side close to the light transmitting member 1" means, for example, the surface of the light transmitting member 1 when observed with a scanning electron microscope (SEM). It means that the density of the voids in the region sandwiched by the line of 300 μm from the surface of the translucent member 1 is higher than the density of the voids in the region outside the region.

(others)
When a member containing a phosphor is used as the light transmitting member 1, it is transparent to at least one of the upper surface of the light transmitting member 1, the upper surface of the light reflecting member 2, the lower surface of the light transmitting member 1, and the lower surface of the light reflecting member 2. It is preferable that the light radiating member 3 is provided. In the first region 2a, the heat dissipation may be lowered due to the high porosity, but by providing the heat dissipation member 3, the heat generated by the light transmission member 1 can be dissipated by the heat dissipation member 3, and the light transmission member 1 can be dissipated. It is possible to improve the temperature characteristics of.
It is preferable that the heat radiating member 3 is directly provided on at least one of the light transmitting member 1 and the light reflecting member 2 in order to improve the heat exhaust property. However, when the heat radiating member 3 is provided with a filter 4 that reflects light from the light transmitting member 1 toward the heat radiating member 3, at least one of the light transmitting member 1 and the light reflecting member 2 is indirectly provided via the filter 4. It may be provided.

Next, a method of manufacturing the optical component 10 will be described with reference to FIGS. 2A to 7B.

The method for manufacturing the optical component 10 includes a step of preparing a light-transmitting member 1 having an upper surface, a lower surface, and a side surface, and a light-reflecting powder made of an inorganic material on the side of the light-transmitting member 1 so as to surround the light-transmitting member 1. The step of forming the molded body 2d including the light reflecting member, and the light reflecting member including the sintered body of the light reflecting powder and the light transmitting member are integrally formed, and light is reflected in one cross section that crosses the light transmitting member 1 and the light reflecting member 2. The member 2 includes a step of sintering the molded body 2d so that a plurality of voids are unevenly distributed in the vicinity of the translucent member 1.

As a result, it is possible to easily manufacture the optical component 10 that reduces the decrease in brightness and secures the strength.

Hereinafter, each step included in the manufacturing method of the optical component 10 will be described. Here, since the same names and symbols indicate members having the same or the same quality as those described above, duplicate description will be omitted as appropriate.

(Step of preparing the translucent member 1)
First, a translucent member 1 having an upper surface, a lower surface, and a side surface is prepared. In this embodiment, a plurality of translucent members 1 are prepared. As a result, the optical component 10 including the plurality of translucent members 1 can be obtained by one sintering, so that mass productivity can be improved.

(Step of temporarily fixing the translucent member 1 to the support member 40)
Next, as shown in FIGS. 2A and 2B, the translucent member 1 is temporarily fixed to the support member 40. As a result, it is possible to prevent the translucent member 1 from tipping over in the step of forming the molded body 2d containing the light-reflecting powder. In addition, the distance between adjacent translucent members 1 can be kept constant. In the present embodiment, resin is provided only between the translucent member 1 and the support member 40, and the translucent member 1 is temporarily fixed to the support member 40. Thereby, in the step of removing the support member 40 from the translucent member 1 and the molded body 2d, the support member 40 can be easily removed without applying excessive force. Although it is preferable to use the support member 40 in consideration of workability, it is not always necessary to use the support member 40.

The material of the support member 40 can be selected according to the method used in the step of forming the molded body 2d. In the present embodiment, since the molded body 2d is formed by the slip casting method (slurry casting molding method), gypsum is used as the support member 40.

When the slip cast method is used to form the molded body 2d, if an adhesive is applied to the entire upper surface of the gypsum, uneven suction may occur and cracks may occur when the water contained in the slurry is absorbed by the gypsum. be. Therefore, here, uneven suction is suppressed by providing the resin only between the translucent member 1 and the support member 40. As the resin, for example, an acrylic resin can be used. As a result, it is possible to prevent the components contained in the resin from entering the slurry due to the reaction between the binder contained in the slurry and the resin.

The light-transmitting member 1 adjacent to the light-transmitting member 1 is temporarily fixed to the upper surface of the support member 40 at a predetermined interval. The distance from the side surface of a certain translucent member 1 to the side surface of the adjacent translucent member 1 can be, for example, in the range of 1 mm or more and 10 mm or less. When the width is 1 mm or more, the width of the second region 2b can be easily secured, and when the width is 10 mm or less, the number of the translucent members 1 included in the optical component obtained by one sintering can be increased.

(Step of forming molded body 2d containing light-reflecting powder)
Next, as shown in FIGS. 3A, 3B, 4A, and 4B, a molded body 2d containing a light-reflecting powder made of an inorganic material is formed on the side of the light-transmitting member 1 so as to surround the light-transmitting member 1. do. In the present embodiment, the molded body 2d is formed on each side surface of the translucent member 1 so as to surround each of the plurality of translucent members 1.

The molded body 2d can be molded by using a slip casting method, a doctor blade method (sheet molding method), a dry molding method, or the like. When the doctor blade method is used, specifically, a slurry in which an additive is mixed so as to cover the translucent member is applied in a sheet form, and then a green sheet in which the slurry is applied in a sheet form is dried to form a molded product. Can be formed. When the dry molding method is used, specifically, a light-reflecting powder made of an inorganic material is filled in a container so as to cover the light-transmitting member, and the light-reflecting powder is pressed to form a molded body. can.

In the present embodiment, the molded body 2d is formed by the slip casting method. Specifically, first, as shown in FIGS. 3A and 3B, a frame body 50 surrounding the plurality of translucent members 1 is arranged on the upper surface of the support member 40. Next, the slurry 2c containing the light-reflecting powder is applied to the inside of the frame body 50. Next, the gypsum is made to absorb the water contained in the slurry 2c. Since gypsum is a material that absorbs water, it may be left at room temperature for several hours, for example. As a result, the molded body 2d containing the light-reflecting powder is formed. At this time, the translucent member 1 and the molded body 2d are not completely fixed to each other, but are molded into a constant shape (hereinafter, the translucent member 1 and the molded body 2d are formed into a constant shape). The molded product is called a "complex"). By using the slip casting method, molding can be performed without pressurization. In addition, the amount of organic substances contained in the slurry can be reduced as compared with the doctor blade method. As a result, the molding density can be increased, so that the possibility of cracks in the light reflecting member 2 during firing can be reduced.

As the frame body 50, one having releasability and water repellency can be used. As a result, it is possible to reduce the sticking of the molded body 2d to the inner surface of the frame body 50. Further, since it is possible to suppress the water contained in the slurry 2c from being absorbed by the frame body 50, it is possible to reduce the unevenness of the molding density of the molded body 2d in the vicinity of the frame body 50. In this embodiment, the frame body 50 made of fluororesin is used.

The slurry 2c of the present embodiment contains a light-reflecting powder containing aluminum oxide and yttrium oxide, a dispersant, a binder, and pure water. The thickness of the slurry 2c is preferably larger than the thickness of the translucent member 1. That is, it is preferable that the slurry 2c covers not only the side surface of the translucent member 1 but also the upper surface. Since it is difficult to make the thickness of the translucent member and the slurry the same, the thickness of the translucent member may be thicker than that of the slurry. In this case, in the step of removing a part of the obtained optical component 10 described later, a force is applied only to the translucent member during polishing or the like, so that the translucent member may be damaged. Therefore, in the present embodiment, the force is suppressed from being applied only to the translucent member 1 by increasing the thickness. The thickness of the slurry 2c is preferably 2 times or more and 4 times or less the thickness of the optical component 10. By setting the number to 2 times or more, it is possible to suppress the peeling between the translucent member 1 and the molded body 2d, so that the support member 40 can be easily removed from the translucent member 1 and the molded body 2d. Further, by setting the value to 4 times or less, the thickness of the optical component 10 to be removed can be reduced in the step of removing a part of the obtained optical component 10.

(Step of removing the support member 40)
Next, as shown in FIGS. 4A and 4B, the support member 40 is removed from the translucent member 1 and the molded body 2d. Although the translucent member 1 and the support member 40 are temporarily fixed with resin, the area of the lower surface of the translucent member 1 is relatively small. Further, the translucent member 1 and the molded body 2d are integrally molded to some extent. For these reasons, the translucent member 1 and the support member 40 can be separated without softening the resin by heating or pulling the resin with excessive force. In the present embodiment, the frame body 50 is removed from the upper surface of the support member 40, and then the composite is removed from the support member 40.

(Degreasing process)
Next, in order to remove the organic substances (dispersant and binder) contained in the composite, the molded product 2d is heated at a temperature lower than the temperature at which it is sintered. The degreasing step can be performed, for example, in a nitrogen atmosphere or an air atmosphere. Heating for degreasing is preferably performed for 3 hours or more in order to reliably remove organic substances. In the present embodiment, the degreasing step and the step of sintering the molded body 2d are performed in separate steps, but in the step of sintering the molded body 2d, degreasing is performed at a low temperature for a certain period of time, and the temperature is kept as it is. The molded product 2d may be sintered at a higher height. When the dry molding method is used in the step of forming the molded body 2d, this step is unnecessary.

(Step of sintering molded body 2d)
Next, the light-reflecting member including the sintered body of the light-reflecting powder and the light-transmitting member are integrally formed, and the light-transmitting member 1 in the light-reflecting member 2 has a cross section that crosses the light-transmitting member 1 and the light-reflecting member 2. The molded body 2d is sintered so that a plurality of voids are unevenly distributed in the vicinity of the above. Such a light reflecting member 2 can be adjusted by adjusting the sintering temperature and the degree of pressurization during sintering. Here, as shown in FIGS. 5A and 5B, by sintering the molded body 2d without pressing it, an optical component 10 in which the sintered body of the light-reflecting powder and the translucent member 1 are integrated is obtained. .. As a result, the optical component 10 including the light reflecting member 2 having the first region 2a and the second region 2b in order from the side of the light transmitting member 1 can be formed. It is considered that the first region 2a and the second region 2b are formed for the following reasons. When the molded product 2d is sintered, the light-reflecting powder shrinks while being combined with other light-reflecting powders nearby. At this time, since the light-reflecting powder is on the entire circumference in the region far from the translucent member 1, the light-reflecting powders are likely to bond with each other and it is difficult to form pores, but the light-reflecting powder is outside in the region near the translucent member 1. Since there is only one, the light-reflecting powders cannot bind to each other and pores are likely to be formed. By sintering without pressing, the sintering is completed while the light-reflecting powders are maintained apart from each other in this way, so that the porosity of the light-reflecting member 2 is high in the vicinity of the light-transmitting member 1. It is considered to be.

A molded body 2d having a light-reflecting powder containing 95.2% by weight of aluminum oxide and 4.8% by weight of yttrium oxide is formed around a translucent member 1 made of ceramics containing a phosphor by a slip casting method. A secondary electron image of the optical component 10 sintered without pressing is observed from the upper surface side, which is shown in FIG. 8A. When measuring the secondary electron image, a carbon film is formed by vapor deposition in order to measure the secondary electron image. The first region 2a of FIG. 8A is darker than the second region 2b due to the voids contained in the first region 2a. Further, FIG. 8B shows an SEM image of the A region of FIG. 8A, and FIG. 8C shows an SEM image of the B region of FIG. 8A. In FIG. 8B, many pores are present in the vicinity of the translucent member 1, whereas in FIG. 8C, the pores are almost eliminated. As can be seen from these results, it can be confirmed that the light reflecting member 2 having regions having different porosities can be formed by sintering the light reflecting powder without pressing to form the light reflecting member 2. rice field.

When aluminum oxide is used as the light-reflecting powder, the sintering temperature is preferably set to 1200 ° C. or higher and 1800 ° C. or lower, and more preferably 1400 ° C. or higher and 1500 ° C. or lower. By setting the temperature to 1200 ° C. or higher, the strength of the light reflecting member 2 can be ensured. Further, by setting the temperature to 1800 ° C. or lower, the possibility that the light transmissivity of the light reflecting member 2 becomes high can be reduced.

In this embodiment, it is sintered in an air atmosphere. The sintering time is preferably set in the range of, for example, 30 minutes or more and 5 hours or less, and more preferably set in the range of 2 hours or more and 4 hours or less. By setting the time to 30 minutes or more, it is possible to easily secure the strength of the light reflecting member 2. Further, by setting the time to 5 hours or less, it is possible to avoid taking more time for sintering than necessary.

(Step of removing a part of the optical component 10)
At this stage, the upper surface of the light transmitting member 1 is covered with the light reflecting member 2. Therefore, as shown in FIGS. 6A and 6B, a part of the optical component 10 is removed from the upper surface side of the optical component 10 until the translucent member 1 is exposed. Examples of the method for removing a part of the optical component 10 include polishing and the like. In the present embodiment, only one side is removed, but in order to remove the deposits on the lower surface of the light transmitting member 1 and the lower surface of the light reflecting member 2, a part of the optical component 10 is further removed from the lower surface side. You may. In the present embodiment, the translucent member 1 is in a polygonal column state, and there is no first region 2a in the portion in contact with the corner, or the width of the first region 2a in the portion in contact with the corner when viewed from above is other than that. It is narrower than the width of the first region 2a of the portion. This step is not always necessary. For example, if an optical component in which the upper surface of the light transmitting member 1 is exposed from the upper surface of the light reflecting member 2 is obtained in the step of sintering the molded body 2d, this step is omitted. You may.

(Individualization process)
Next, as shown in FIGS. 7A and 7B, one optical component 10 is fragmented into a plurality of optical components 10 so as to include one translucent member 1. For example, a blade can be used to separate the optical components 10 into individual pieces. In the present embodiment, one optical component 10 is fragmented so as to include one translucent member 1, but one optical component 10 is fragmented so as to include a plurality of translucent members 1. May be good. Further, this step is not always necessary. For example, when a desired optical component 10 can be obtained by a step of sintering the molded body 2d or a step of removing a part of the optical component 10, this step is performed. It may be omitted.

<Second Embodiment>
FIG. 9 shows a schematic view of a light emitting device 100 in which the optical component 20 and the light emitting element 60 according to the second embodiment are combined. The optical component 20 is substantially the same as the items described in the optical component 10 except for the items described below.

The optical component 20 is provided with a heat radiating member 3 on both the lower surface of the light transmitting member 1 and the lower surface of the light reflecting member 2 via an insulating film 5 and a filter 4 in this order from the light transmitting member 1 side. Although the heat radiating member 3 may be provided on one of the lower surface of the light transmitting member 1 and the lower surface of the light reflecting member 2, it is preferable to provide the heat radiating member 3 on both of them in consideration of heat dissipation as in the present embodiment. Although it is possible to provide a heat radiating member on at least one of the upper surface of the light transmitting member 1 and the upper surface of the light reflecting member 2, at least the lower surface of the light transmitting member 1 and the lower surface of the light reflecting member 2 as in the present embodiment. It is preferable that the light-transmitting heat-dissipating member 3 is provided on one side. When the heat radiating member 3 is joined to the light transmitting member 1, the surface of the light transmitting member 1 may be flattened by polishing or the like. In this case, the first region 2a of the light reflecting member 2 due to the rate difference such as polishing. However, it may be removed with priority over the light transmitting member 1 and the second region 2b, and as a result, the first region 2a may be partially recessed to form a groove. Therefore, if it is attempted to provide a heat radiating member on at least one of the upper surface of the light transmitting member and the upper surface of the light reflecting member, the brightness is lowered because the light escapes from the groove formed in the first region above the light extraction side. There is a risk of Therefore, as in the present embodiment, it is preferable to provide the heat radiating member 3 on at least one of the lower surface of the light transmitting member 1 and the lower surface of the light reflecting member 2.

In the optical component 20, since the heat generated by the translucent member 1 can be exhausted to the heat radiating member 3, deterioration of the translucent member 1 can be reduced.

In the present embodiment, as the filter 4, a filter 4 that easily transmits the light from the light emitting element 60 and easily reflects the fluorescence of the light transmitting member 1 is used. In the present embodiment, a light emitting element 60 that emits blue light is used, and a light transmitting member 1 that includes a phosphor that emits yellow light when irradiated with blue light is used. Therefore, the filter 4 that easily transmits blue light and easily reflects yellow light is used.

In the present embodiment, the filter 4 and the lower surface of the light transmitting member 1 and the lower surface of the light reflecting member 2 are joined via an insulating film 5. In the present embodiment, in order to join the filter 4 and the light transmitting member 1 and the like by the surface activation joining method, the lower surface of the light transmitting member 1 and the lower surface of the light reflecting member 2 are polished. At this time, a groove is formed in the vicinity of the boundary between the light transmitting member 1 and the light reflecting member 2 due to the difference in polishing rate between the light transmitting member 1 and the light reflecting member 2. If the surface activation joining method is performed with the grooves, a gap is formed between the light transmitting member 1 and the heat radiating member 3, so that the heat radiating property may be deteriorated. Therefore, the groove is filled with the insulating film 5 to reduce the decrease in heat dissipation.

In this embodiment, aluminum oxide is used as the insulating film 5. In addition to this, for example, silicon oxide and titanium oxide can be used. The insulating film 5 is preferably formed with a film thickness sufficient to fill the groove in order to suppress a decrease in heat dissipation. In the present embodiment, the filter 4 and the translucent member 1 are bonded by the surface activation bonding method, but the filter 4 and the translucent member 1 may be bonded by the atomic diffusion bonding method. In this case, a metal film is formed on the upper surface of the filter and the lower surface of the translucent member, respectively, and the metal films are bonded to each other to bond the filter and the translucent member.

In the light emitting device 100 shown in FIG. 9, a laser element (Laser Diode, LD) is used as the light emitting element 60. The LD is arranged apart from the optical component 20 so that the light from the LD passes through the translucent member 1 included in the optical component 20. When phosphor ceramics containing a phosphor are used as the light transmitting member 1 and LD is used as the light emitting element 60, the need for exhaust heat from the light transmitting member 1 increases. Therefore, the effect of improving the heat exhaust property by providing the heat radiating member 3 becomes more remarkable.

<Third Embodiment>
FIG. 10A shows a top view of a light emitting device 200 in which the optical component 30 and the light emitting element 60 according to the third embodiment are combined, and FIG. 10B shows a cross-sectional view taken along the line 10B-10B of FIG. 10A. The optical component 30 is substantially the same as the items described in the optical component 10 except for the items described below.

The optical component 30 includes a plurality of translucent members 1 in one optical component 30. The light reflecting member 2 has a first region 2a around each light transmitting member 1 and a second region 2b outside the first region 2a.

In the light emitting device 200 shown in FIGS. 10A and 10B, a plurality of light emitting elements 60 are provided on the upper surface of the substrate 70. In the light emitting device 200, a light emitting diode (Light Emitting Diode, LED) is used as the light emitting element 60. Then, one optical component 30 is arranged on the upper surface of the plurality of light emitting elements 60 so that one translucent member 1 is located on the upper surface of the one light emitting element 60. Further, a light reflecting resin 80 is arranged around the light emitting element 60.

In the light emitting device 200, the light from one light emitting element 60 is arranged so as to pass through one light transmitting member 1, but the light from two or more light emitting elements passes through one light transmitting member. Optical components and light emitting elements may be arranged.

<Example>
Optical parts were manufactured by the following manufacturing methods. First, as the translucent member 1, a rectangular parallelepiped fluorescent ceramic having a short side of 500 μm, a long side of 1000 μm, and a height of 600 μm was prepared.
As the phosphor ceramic, phosphor ceramic made of a sintered body containing a YAG phosphor and aluminum oxide was used.

Next, the molded body 2d was formed by the slip casting method. Specifically, the molded body 2d was formed by the following method. First, the phosphor ceramics were placed on an acrylic resin sheet, and the acrylic resin was transferred to the lower surface of the phosphor ceramics by applying pressure. Then, the lower surface of the phosphor ceramic was temporarily fixed to the upper surface of the gypsum which is the support member 40 via the resin. Then, a frame body 50 made of a Teflon (registered trademark) ring having an inner diameter of 30 mm was fixed to the upper surface of the support member 40 so as to surround the fluorescent ceramics. Next, the slurry 2c was filled inside the frame 50 until the upper surface of the translucent member 1 became invisible. As the slurry 2c, a slurry containing 76.4% of a light-reflecting powder, 0.7% of a dispersant, 2.4% of a binder, and 20.5% of pure water was used. The light-reflecting powder contains 95.2% by weight of aluminum oxide and 4.8% by weight of yttrium oxide. The dispersant contains an ammonium polycarboxylic acid-based material, and the binder includes an acrylic-based material. Then, it was left overnight to allow the gypsum to absorb the water contained in the slurry 2c to form the molded product 2d. That is, a composite in which the fluorescent ceramics and the molded body 2d were molded into a constant shape was formed.

Next, after removing the frame body 50, the composite body was removed from the support member 40. At this time, the lower surface of the fluorescent ceramics and the gypsum are temporarily fixed with an adhesive, but since the area of the lower surface of the phosphor ceramics is relatively small, the composite can be removed from the support member 40. Then, the complex was degreased by heating at 700 ° C. for 3 hours in a nitrogen atmosphere. Next, it was calcined at 1450 ° C. for 2 hours. As a result, the phosphor ceramic and the light reflecting member 2 are integrated, and an optical component in which the side surface and the upper surface of the phosphor ceramic are covered with the light reflecting member 2 is obtained. Next, the obtained optical component was polished from the upper surface side until the upper surface of the phosphor ceramic was exposed. As a result, when viewed from above, an optical component in which the fluorescent ceramics were surrounded by the light reflecting member 2 was obtained.

FIG. 11 shows a photograph of the obtained optical component obtained by dark-field observation using an epi-illumination microscope. In FIG. 11, the rectangular member at the center is the light transmitting member 1, and the light reflecting member 2 is outside the light transmitting member 1. In the light reflecting member 2, the black portion is the first region 2a, and the outer region thereof is the second region 2b. As shown in FIG. 11, in the first region 2a, since the porosity is high, there are many shadows due to the pores, so that the second region 2b looks black, and the second region 2b has a low porosity. It is considered that there are few shadows and there is no color.

The optical components described in each embodiment can be used for lighting, vehicle lamps, and the like.

1 ... Light-transmitting member 2 ... Light-reflecting member 2a ... 1st region 2b ... 2nd region 2c ... Slurry 2d ... Molded body 3 ... Heat-dissipating member 4 ... Filter 5 ... Insulating film 10, 20, 30 ... Optical component 40 ... Support member 50 ... Frame 60 ... Light emitting element 70 ... Substrate 80 ... Light reflective resin 100, 200 ... Light emitting device

Claims (17)

A translucent member having an upper surface, a lower surface and a side surface,
A light reflecting member provided on the side of the translucent member so as to surround the transmissive member is provided.
The light reflecting member is made of ceramics containing a plurality of voids.
The light reflecting member, Rukoto to Yusuke a first region of a first porosity and a second region of a second porosity porosity is lower than the first porosity from the side closer to the light transmitting member in this order An optical component characterized by. The optical component according to claim 1, wherein the light reflecting member is provided in contact with a side surface of the translucent member. The optical component according to claim 1 or 2, wherein the translucent member is made of a ceramic containing a phosphor or a single crystal of the phosphor. The optical component according to any one of claims 1 to 3, wherein the light reflecting member contains aluminum oxide. The optical component according to claim 4, wherein the translucent member is made of a fluorescent ceramics containing a YAG-based phosphor or a single crystal of the YAG-based phosphor. Any one of claims 1 to 5, wherein a light-transmitting heat-dissipating member is directly or indirectly provided on at least one of the lower surface of the light-transmitting member and the lower surface of the light-reflecting member. Optical components described in. The optical component according to any one of claims 1 to 6, wherein the width of the first region is narrower than the width of the second region. The optical component according to any one of claims 1 to 7, wherein the width of the first region is 50 μm or more and 300 μm or less. A light emitting device including the optical component according to any one of claims 1 to 8 and a light emitting element. The process of preparing a translucent member having an upper surface, a lower surface, and a side surface, and
A step of forming a molded body containing a light-reflecting powder made of an inorganic material on the side of the light-transmitting member so as to surround the light-transmitting member.
The light-reflecting member containing the sintered body of the light-reflecting powder and the light-transmitting member are integrally formed, and the light-reflecting member has a first region of a first porosity and a porosity higher than the first porosity. method of manufacturing an optical component and a step of sintering the shaped body to chromatic sequentially to the second region of the lower second porosity from the side closer to the light transmitting member. The method for manufacturing an optical component according to claim 10, wherein in the step of sintering the molded body, the molded body is sintered without pressing. The method for manufacturing an optical component according to claim 10 or 11, wherein in the step of forming the molded body, the molded body is formed by a slip casting method. The method according to any one of claims 10 to 12, wherein in the step of preparing the translucent member, a phosphor ceramic containing a phosphor or a single crystal of the phosphor is prepared as the translucent member. Manufacturing method of optical parts. In the step of preparing the translucent member, a plurality of translucent members are prepared.
10. The method for manufacturing an optical component according to. Between the step of preparing the translucent member and the step of forming the molded body, the step of temporarily fixing the transmissive member to the support member, only between the transmissive member and the support member. It has a step of providing a resin and temporarily fixing the translucent member to the support member.
10.14 of claims 10 to 14, wherein a step of removing the light-transmitting member and the support member from the molded body is provided between the step of forming the molded body and the step of sintering the molded body. The method for manufacturing an optical component according to any one item. The method for manufacturing an optical component according to any one of claims 10 to 15, wherein the width of the first region is narrower than the width of the second region. The method for manufacturing an optical component according to any one of claims 10 to 16, wherein the width of the first region is 50 μm or more and 300 μm or less.

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