Light-transmitting member and manufacturing method thereof, optical member, and light-emitting device

Abstract

To provide a translucent member, light-emitting device, etc., which allow for emitting light of adjusted chromaticity.SOLUTION: A translucent member provided herein has a light transmissive section with an exit surface for allowing light to exit, and a film-like metal area having a thickness in a range of 1-10 nm, inclusive, or a metal area having particulate metal pieces with a maximum length in a range of 1-100 nm, inclusive, in a direction perpendicular to the exit surface dispersed therein.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a light-transmitting member, a method for manufacturing the same, an optical member, and a light-emitting device. [Background technology]

[0002] There is known a light-transmitting member in which a metal is formed in a part of a light-transmitting portion containing a phosphor. For example, Patent Document 1 discloses a technique of a fluorescent composite in which a metal is adhered to the surface of a phosphor in order to utilize the plasmon (near-field) effect of the metal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-209570 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a light-transmitting member, a light-emitting device, and the like that are capable of emitting light with adjusted chromaticity. [Means for solving the problem]

[0005] A light-transmitting member according to an embodiment of the present disclosure includes a light-transmitting portion having an exit surface from which light is emitted, and a metal region formed on the exit surface, the metal region being a film having a thickness of 1 nm or more and 10 nm or less, or a metal region having dispersed particulate metal having a maximum length of 1 nm or more and 100 nm or less in a direction perpendicular to the exit surface. death , The light-transmitting portion has a phosphor, and the phosphor is cerium-activated yttrium aluminum garnet. .

[0006] Moreover, an optical member according to an embodiment of the present disclosure includes a light-transmitting member according to an embodiment of the present disclosure and a light-transmitting plate-like member arranged on the incident surface side of the light transmitting portion.

[0007] Furthermore, a light emitting device according to an embodiment of the present disclosure includes a translucent member according to an embodiment of the present disclosure or an optical member according to an embodiment of the present disclosure, and the translucent member causes light emitted from the light emitting element to exit from the emission surface through the metal region.

[0008] Furthermore, a method for manufacturing a light-transmitting member according to one embodiment of the present disclosure includes the steps of preparing a light-transmitting portion having an exit surface from which light is emitted, providing a metal film having a thickness of 1 nm or more and 10 nm or less on the exit surface, and heating the metal film formed on the exit surface to form a metal region containing metal that has been particulated by heating. [Effects of the Invention]

[0009] According to an embodiment of the present disclosure, it is possible to provide a light-transmitting member, an optical member, or a light-emitting device capable of emitting light with adjusted chromaticity. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view illustrating a light-transmitting member according to the first embodiment. [Figure 2] 2 is a cross-sectional view taken along line II-II in FIG. 1, illustrating the light-transmissive member according to the first embodiment. [Figure 3] 4A to 4C are views (part 1) illustrating a method for manufacturing a light-transmitting member according to the first embodiment. [Figure 4] 5A and 5B are diagrams (part 2) illustrating the method for manufacturing the light-transmitting member according to the first embodiment. [Figure 5A] This is an SEM photograph of a metal film formed to a thickness of 1 nm before heating. [Figure 5B] This is another SEM photograph of a metal film formed to a thickness of 1 nm before heating. [Figure 6A] This is an SEM photograph of a metal film formed to a thickness of 1 nm after heating. [Figure 6B] This is another SEM photograph of a metal film formed to a thickness of 1 nm after heating. [Figure 7A] This is an SEM photograph of a metal film formed to a thickness of 2 nm after heating. [Figure 7B] This is another SEM photograph of a metal film formed to a thickness of 2 nm after heating. [Figure 8A] This is an SEM photograph of a metal film formed to a thickness of 3 nm after heating. [Figure 8B] This is another SEM photograph of a metal film formed to a thickness of 3 nm after heating. [Figure 9A] This is an SEM photograph of a metal film formed to a thickness of 5 nm after heating. [Figure 9B] This is another SEM photograph of a metal film formed to a thickness of 5 nm after heating. [Figure 10] FIG. 10 is a diagram illustrating the change in linear transmittance of a metal film with a film thickness of 1 nm before and after heating. [Figure 11] FIG. 10 is a diagram illustrating the change in in-line transmittance of a metal film with a film thickness of 2 [nm] before and after heating. [Figure 12] FIG. 10 is a diagram illustrating an example of the change in linear transmittance of a metal film with a film thickness of 3 nm before and after heating. [Figure 13] FIG. 10 is a diagram illustrating the change in linear transmittance of a metal film with a film thickness of 5 nm before and after heating. [Figure 14] 10 is a cross-sectional view illustrating a light-transmitting member according to a first modified example of the first embodiment. FIG. [Figure 15] FIG. 10 is a diagram illustrating the change in linear transmittance before and after heating when a protective film is formed on a metal film with a film thickness of 1 [nm]. [Figure 16] FIG. 10 is a diagram illustrating the change in linear transmittance before and after heating when a protective film is formed on a metal film with a film thickness of 2 [nm]. [Figure 17] 10 is a cross-sectional view illustrating a light-transmitting member according to a second modification of the first embodiment. FIG. [Figure 18] FIG. 10 is a perspective view illustrating an optical member according to a second embodiment. [Figure 19] 19 is a cross-sectional view taken along line XIX-XIX in FIG. 18, illustrating an optical member according to a second embodiment. [Figure 20] FIG. 10 is a perspective view illustrating a light emitting device according to a third embodiment. [Figure 21]21 is a cross-sectional view taken along line XXI-XXI in FIG. 20, illustrating the light-emitting device according to the third embodiment. [Figure 22] FIG. 11 is a perspective view of the light emitting device according to the third embodiment, from which optical members have been further removed. [Figure 23] FIG. 11 is a plan view of the light emitting device according to the third embodiment, from which optical members have been further removed. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a description will be given of an embodiment of the invention with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms including these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. Furthermore, parts that appear with the same reference numerals in multiple drawings indicate the same or equivalent parts or components.

[0012] Furthermore, in this disclosure, polygons such as triangles and quadrilaterals are referred to as polygons, including shapes in which the corners of the polygons have been processed, such as by rounding, chamfering, corner removal, or rounding. Shapes in which processing has been applied not only to the corners (edges of the sides) but also to the middle portions of the sides are also referred to as polygons. In other words, shapes in which partial processing has been applied while retaining the polygon as a base are included in the interpretation of "polygon" described in this disclosure.

[0013] The same applies to words that represent specific shapes, such as trapezoids, circles, and irregularities, not just polygons. The same also applies when dealing with the sides that form the shape. In other words, even if the corners or middle part of a side have been processed, the interpretation of "side" includes the processed part. Note that when distinguishing a "polygon" or "side" that has no processing from a processed shape, the word "strict" is added, for example, "strict quadrangle."

[0014] Furthermore, the embodiments described below are intended to exemplify translucent members and the like to embody the technical concepts of the present invention and are not intended to limit the scope of the present invention. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, and the like of the components described below are intended for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, part or all of the content described in one embodiment may also be applied to other embodiments or modifications. At least, when content described in one embodiment appears in drawings relating to other embodiments or modifications, this indicates that the content is also applicable to those other embodiments or modifications. Furthermore, the size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, to avoid overly complex drawings, schematic diagrams may be used in which some elements are omitted, or end views may be used as cross-sectional views showing only the cut surface.

[0015] First Embodiment Fig. 1 is a perspective view illustrating a light-transmitting member according to the first embodiment, and Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1 illustrating the light-transmitting member according to the first embodiment.

[0016] As shown in FIGS. 1 and 2, the light-transmitting member 10 includes a composite member 13 and a metal region 15.

[0017] Each component of the light-transmitting member 10 will be described.

[0018] (Composite material 13) The composite member 13 has a light-transmitting portion 11 and a light-reflecting portion 12. However, the light-reflecting portion 12 is not an essential component and is provided as needed. For example, in FIG. 1 , the portion where the light-reflecting portion 12 is provided may be a light-transmitting portion that is the same as the light-transmitting portion 11 or a light-transmitting portion separate from the light-transmitting portion 11.

[0019] The light-transmitting portion 11 has an upper surface 11a, a lower surface 11b opposite the upper surface 11a, and one or more side surfaces 11c intersecting with the upper surface 11a and the lower surface 11b. The one or more side surfaces 11c connect the outer edge of the upper surface 11a to the outer edge of the lower surface 11b. The light-transmitting portion 11 is, for example, a rectangular parallelepiped or a cube. In this case, the upper surface 11a and the lower surface 11b of the light-transmitting portion 11 are both rectangular, and the light-transmitting portion 11 has four rectangular side surfaces 11c. The rectangle referred to here means a rectangle or a square.

[0020] However, the light-transmitting portion 11 is not limited to a rectangular parallelepiped or a cube. For example, the planar shape of the light-transmitting portion 11 is not limited to a rectangle, and can be any shape such as a circle, an ellipse, or a polygon. In the case of a cylindrical light-transmitting portion 11, both the upper surface 11a and the lower surface 11b of the light-transmitting portion 11 are circular, and the light-transmitting portion 11 has one cylindrical side surface 11c along the circumference. Note that viewing an object from the normal direction of the upper surface 11a of the light-transmitting portion 11 may be referred to as a planar view, and the shape of the object viewed from the normal direction of the upper surface 11a of the light-transmitting portion 11 may be referred to as a planar shape.

[0021] The light transmitting portion 11 transmits light from the lower surface 11b to the upper surface 11a, for example. Light that enters from the lower surface 11b and travels upward can be emitted from the upper surface 11a. The lower surface 11b can be the incident surface where light enters, and the upper surface 11a can be the exit surface where light exits. Note that the upper surface 11a may be both the incident surface where light enters and the exit surface where light exits. The light transmitting portion 11 has translucency that transmits light. The light transmitting portion 11 may be translucent for light in a wavelength range of, for example, 400 nm or more and 760 nm or less. In this application, "translucent for light" means that the transmittance for the light is 80% or more. Furthermore, when the light is light over a certain wavelength range, it means that the transmittance for at least the peak wavelength of the light is 80% or more.

[0022] Because the light-transmitting portion 11 is irradiated with light, the base material of the light-transmitting portion 11 is preferably formed using an inorganic material that is not easily decomposed by light irradiation as the main material. The main material is, for example, ceramics. Examples of ceramics used as the main material include aluminum oxide, aluminum nitride, silicon oxide, yttrium oxide, zirconium oxide, and magnesium oxide. The main ceramic material is preferably a material with a melting point of 1300°C to 2500°C so that the light-transmitting portion 11 does not undergo deterioration such as deformation or discoloration due to heat. The light-transmitting portion 11 is, for example, a sintered body formed using ceramics as the main material. The main material is the material that accounts for the largest proportion of its constituent elements in terms of weight ratio or volume ratio. The main material may also include the case where no other materials are included, that is, the constituent element is formed solely from the main material.

[0023] The light transmitting section 11 may be a wavelength converting section having a phosphor. When the light transmitting section 11 is a wavelength converting section, the light transmitting section 11 can, for example, convert light incident from the incident surface into light of a different wavelength and emit the converted light from the emission surface. The light transmitting section 11 may emit a portion of the incident light. The light transmitting section 11 may also convert all of the incident light into light of a different wavelength. In this case, the light incident on the light transmitting section 11 is not emitted from the light transmitting section 11.

[0024] When the light transmitting section 11 is a wavelength conversion section, the light transmitting section 11 can be formed, for example, by sintering a phosphor and a light-transmitting material such as aluminum oxide. The content of the phosphor can be 0.05% by volume to 50% by volume with respect to the total volume of the ceramic. Alternatively, for example, ceramics consisting essentially of phosphor, obtained by sintering phosphor powder, may be used. Alternatively, the light transmitting section 11 may be formed of a single crystal of phosphor.

[0025] Examples of phosphors include cerium-activated yttrium aluminum garnet (YAG), cerium-activated lutetium aluminum garnet (LAG), europium-activated silicate ((Sr,Ba)2SiO4), α-sialon phosphor, β-sialon phosphor, etc. Among them, garnet-based phosphors such as YAG phosphor and LAG phosphor have good heat resistance.

[0026] For example, one possible application is that the light-transmitting portion 11 contains a YAG phosphor and blue light is made incident on the light-transmitting portion 11. In this case, when blue excitation light is incident, the blue excitation light and the fluorescent light are mixed together, and white light can be emitted.

[0027] The light reflecting portion 12 is, for example, a frame-shaped member having a rectangular opening. The light reflecting portion 12 has an upper surface 12a, a lower surface 12b opposite the upper surface 12a, one or more inner surfaces 12c connecting the inner edge of the upper surface 12a with the inner edge of the lower surface 12b, and one or more outer surfaces 12d connecting the outer edge of the upper surface 12a with the outer edge of the lower surface 12b. The outer and inner edges of the upper surface 12a and the outer and inner edges of the lower surface 12b are, for example, rectangular. In this case, the light reflecting portion 12 has four rectangular inner surfaces 12c and four rectangular outer surfaces 12d. Note that the outer and inner edges of the upper surface 12a and the outer and inner edges of the lower surface 12b are not limited to rectangular shapes and can be any shape, such as circular, elliptical, or polygonal.

[0028] The light reflecting portion 12 is, for example, a sintered body formed using ceramic as the main material. Examples of ceramics used as the main material include aluminum oxide, aluminum nitride, silicon oxide, yttrium oxide, zirconium oxide, and magnesium oxide. Aluminum oxide is one of the preferred materials in relation to the method of forming the light reflecting portion 12 described below. However, the light reflecting portion 12 does not have to be formed using ceramic as the main material. The light reflecting portion 12 may be formed using, for example, metal, a composite of ceramic and metal, or the like.

[0029] In the composite member 13, the inner surface 12c of the light reflecting portion 12 is connected to the side surface 11c of the light transmitting portion 11. The composite member 13 has a flat plate shape, for example, a rectangular parallelepiped. However, the shape of the composite member 13 is not limited to this, and may be, for example, a cylindrical flat plate shape, or may have a shape in which the light transmitting portion 11 is recessed more than the light reflecting portion 12.

[0030] The upper surface 11a of the light transmitting portion 11 and the upper surface 12a of the light reflecting portion 12 may form one continuous plane. The lower surface 11b of the light transmitting portion 11 and the lower surface 12b of the light reflecting portion 12 may form one continuous plane. Alternatively, the composite member 13 may have a shape in which the upper surface 11a and / or the lower surface 11b of the light transmitting portion 11 protrudes further than the upper surface 12a and / or the lower surface 12b of the light reflecting portion 12. In this case, part of the side surface 11c of the light transmitting portion 11 is connected to the inner surface 12c of the light reflecting portion 12.

[0031] The light transmitting portion 11 and the light reflecting portion 12 may be prepared as separate bodies and then joined together to form the light transmitting portion 11. Alternatively, the light transmitting portion 11 and the light reflecting portion 12 may be formed as a single body. The light transmitting portion 11 and the light reflecting portion 12 may be formed as a single sintered body, for example. It is also possible to adjust the porosity of the light transmitting portion 11 and the light reflecting portion 12. The porosity can be adjusted by the sintering conditions (sintering temperature, sintering time, heating rate), the particle size of the material, the concentration of the sintering aid, etc.

[0032] The light reflecting portion 12 has a two-dimensional or three-dimensional reflective region that reflects light on or near one or more inner surfaces 12c. For example, when forming the light reflecting portion 12 using ceramics as the main material, the light reflecting portion 12 can be formed to have voids near one or more inner surfaces 12c, thereby forming the light reflecting portion 12 with a reflective region. Note that it is not necessary to have voids only near one or more inner surfaces 12c, and the light reflecting portion 12 may be formed with voids throughout. The light reflecting portion 12 formed mainly from aluminum oxide can provide a reflective region with high reflectivity by having voids, and is therefore one of the preferred materials for the light reflecting portion 12.

[0033] In the composite member 13, the porosity of the light-reflecting portion 12 is greater than the porosity of the light-transmitting portion 11. In other words, the composite member 13 is formed so that the light-reflecting portion 12 contains more voids than the light-transmitting portion 11. It is preferable to adjust the sintering conditions so that the porosity of the light-reflecting portion 12 is approximately 10%. This forms a reflective area of ​​air at the boundary between the side surface 11c of the light-transmitting portion 11 and the inner surface 12c of the light-reflecting portion 12, allowing light that strikes the inner surface 12c of the light-reflecting portion 12 from the light-transmitting portion 11 side to be reflected back toward the light-transmitting portion 11 side. It is preferable to adjust the sintering conditions so that the porosity of the light-transmitting portion 11 is 20% or less. This allows the light-reflecting portion 12 to have sufficient strength.

[0034] (metal area 15) The metal region 15 is a metal film having a thickness of 1 nm to 10 nm. Alternatively, the metal region 15 is a region in which granular metal is dispersed, with the maximum length in the thickness direction being 1 nm to 100 nm. The granular metal constituting the metal region 15 can be formed, for example, by heat-treating a metal film formed to a thickness of 1 nm to 10 nm. A metal film can be formed if it is 1 nm or thicker, and if it is 10 nm or thinner, a certain level of transmittance or higher can be obtained in the wavelength range of 400 nm to 760 nm. Hereinafter, the metal region 15 in which granular metal is dispersed will be referred to as a granular metal distribution.

[0035] The metal region 15 has a transmittance bottom wavelength in the wavelength range of 400 nm to 760 nm. Here, the transmittance bottom wavelength is the wavelength at which the linear transmittance of the metal region 15 is minimum for light in the wavelength range of 400 nm to 760 nm that is incident on the metal region 15. The transmittance bottom wavelength of the metal region 15 coincides with the absorption peak wavelength of the metal region 15. Therefore, by measuring the linear transmittance of the metal region 15 in the wavelength range of 400 nm to 760 nm and determining the transmittance bottom wavelength at which the linear transmittance is minimum, the absorption peak wavelength of the metal region 15 in the wavelength range of 400 nm to 760 nm can be determined. Furthermore, the wavelength at which the linear transmittance of the metal region 15 is maximum for light in the wavelength range of 400 nm to 760 nm that is incident on the metal region 15 is defined as the transmittance peak wavelength.

[0036] In the present application, the linear transmittance of the metal region 15 was measured as follows. First, a plate-shaped sapphire (without the metal region 15) with a thickness of approximately 400 μm and mirror-finished on one side and the opposite side was prepared. The sapphire was a substrate on which a metal film was formed, and could also be referred to as a substrate on which the metal region 15 was formed. The ratio of light perpendicularly emitted from one side to light perpendicularly incident on the other side of the sapphire plate was measured, and the measurement result was designated as linear transmittance S (%). Next, a metal region 15 was formed on one side of the sapphire plate, and the ratio of light perpendicularly emitted from the metal region 15 to light perpendicularly incident on the other side of the sapphire plate was measured, and the measurement result was designated as linear transmittance M (%). The light incident on the other side of the sapphire plate included a wavelength range of at least 400 nm to 760 nm.

[0037] Here, the value of linear transmittance M / linear transmittance S is referred to as the linear transmittance (%) of the metal region 15. Furthermore, linear transmittance S - linear transmittance M is referred to as the transmittance reduction (%) of the metal region 15. The transmittance reduction is a parameter that indicates the extent to which light is less transmitted than when only the coated member is used, expressed as a percentage of incident light. Furthermore, the value of 100 - linear transmittance S + linear transmittance M is referred to as the pseudo-linear transmittance (%) of the metal region 15. The pseudo-linear transmittance is the value obtained by subtracting the transmittance reduction from 100%, and is referred to as a parameter that indicates the proportion of transmitted light, rather than the proportion of the transmitted light that is reduced.

[0038] The linear transmittance of the metal region 15 at the transmittance bottom wavelength is defined as the bottom transmittance (%). The transmittance at which the linear transmittance is (bottom transmittance (%) + 100(%)) / 2, that is, the transmittance at which the decrease in transmittance is half of the bottom transmittance, is used as a reference, and the width of two wavelengths at this transmittance is defined as the full width at half maximum of the bottom transmittance. One of the two wavelengths that form the reference transmittance is within a wavelength range where the transmittance monotonically increases from the bottom transmittance in the positive wavelength direction, and the other is within a wavelength range where the transmittance monotonically increases from the bottom transmittance in the negative wavelength direction. If there are no two wavelengths that satisfy this condition, the transmittance that is half the value based on the bottom transmittance and this reference transmittance is used as the reference transmittance. In other words, the width of two wavelengths that are within the wavelength range and at this transmittance is defined as the pseudo full width at half maximum of the bottom transmittance, based on the transmittance at (bottom transmittance (%) + ((bottom transmittance (%) + 100(%)) / 2)) / 2. Here, when distinguishing between the former reference transmittance and the latter reference transmittance, the former is called the primary reference transmittance and the latter is called the secondary reference transmittance. If there are no two wavelengths that satisfy the conditions for the secondary reference transmittance, the transmittance at half the value is similarly used as the reference. This transmittance is called the tertiary reference transmittance, and Nth-order reference transmittances from the tertiary onwards can be determined using the same regularity.

[0039] Hereinafter, we may refer to the full width at half maximum of the bottom transmittance of one metal region 15 produced under certain conditions. In this case, we will refer to the full width at half maximum of the bottom transmittance at the Nth-order reference transmittance where N is the smallest. In other words, we may refer to the full width at half maximum of a pseudo bottom transmittance. We may also compare the full width at half maximum of the bottom transmittance of two or more metal regions 15 produced under different conditions. In this case, we will refer to the full width at half maximum of the bottom transmittance when there are two wavelengths in both of the two metal regions 15 and when N is the smallest. Note that, depending on the object of comparison, such an N may not exist. Hereinafter, we will simply refer to this Nth-order reference transmittance as the "reference transmittance."

[0040] Similarly, the pseudo-linear transmittance of the metal region 15 at the transmittance bottom wavelength is defined as the pseudo-bottom transmittance (%). The full width at half maximum of the pseudo-bottom transmittance can also be calculated based on the pseudo-linear transmittance using the same calculation principle as for the full width at half maximum of the bottom transmittance. The Nth-order reference pseudo-transmittance can also be determined in the same way.

[0041] The bottom transmittance of the metal region 15 is 45% or more and 98% or less. In order to balance the amount of light and chromaticity adjustment, in one embodiment, the bottom transmittance of the metal region 15 is preferably 70% or more and 95% or less. In addition, the difference between the maximum transmittance and the bottom transmittance of the metal region 15 in the wavelength range of 400 nm or more and 760 nm or less (transmittance gap) is 5% or more and 30% or less. In order to effectively adjust the chromaticity, in one embodiment, the transmittance gap is preferably 5% or more and 20% or less.

[0042] Since the metal region 15 has at least one transmittance bottom wavelength (= absorption peak wavelength) in the wavelength range of 400 nm or more and 760 nm or less, the chromaticity point of the light emitted from the metal region 15 can be shifted relative to the chromaticity point of the light in the wavelength range of 400 nm or more and 760 nm or less that is incident on the metal region 15.

[0043] The pseudo-bottom transmittance of the metal region 15 is 50% or more and 95% or less. In order to balance the light amount and chromaticity adjustment, in one embodiment, the pseudo-bottom transmittance of the metal region 15 is preferably 80% or more and 95% or less. In addition, the difference between the maximum pseudo-transmittance and the pseudo-bottom transmittance of the metal region 15 in the wavelength range of 400 nm or more and 760 nm or less (pseudo-transmittance gap) is 5% or more and 30% or less. In order to effectively adjust the chromaticity, in one embodiment, the pseudo-transmittance gap is preferably 5% or more and 20% or less.

[0044] The metal region 15 can be formed containing particulate metal. Here, "particulate" does not mean that the metal is formed continuously, but refers to a state in which the metal contains independent particles. However, some particles may be connected to each other. The shape of the particles may be any shape, including spherical, flat, star-shaped, irregular, etc. The size of the particles does not need to be uniform, and large and small particles may be mixed. The metal region 15 may be formed only from particles.

[0045] Metal granulation can be achieved by forming a thin metal film on the order of nanometers and then heat-treating it. In this case, however, the size of the granulated metal differs from the film thickness when formed. Therefore, when a metal film is granulated, even if the film thickness of the metal film is 1 nm or more and 10 nm or less, the particle diameter of the granulated metal may be larger than the film thickness. Furthermore, the maximum length of the granulated metal in the same direction as the film thickness (in this case, the direction perpendicular to the film formation surface) may be larger than the film thickness of the metal film.

[0046] By adjusting the conditions for including particulate metal in the metal region 15, it is possible to adjust the transmittance bottom wavelength of the metal region 15 for light in the wavelength range of 400 nm to 760 nm that is incident on the metal region 15. Adjusting the conditions is not limited to adjusting whether or not to include particulate metal in the metal region 15, but may also include adjusting the formation state of the particulate metal, such as its distribution and size. By changing the conditions, it is possible to change the transmittance bottom wavelength of the metal region 15. Furthermore, by changing the conditions, it is possible to change the transmittance at the transmittance bottom wavelength of the metal region 15. Furthermore, by changing the conditions, it is possible to narrow the full width at half maximum of the bottom transmittance of the metal region 15 for light in the wavelength range of 400 nm to 760 nm that is incident on the metal region 15.

[0047] In a metal region 15 containing particulate metal, the transmittance bottom wavelength of the metal region 15 tends to be shifted to the shorter wavelength side compared to a metal region 15 (e.g., a metal film) that does not contain particulate metal. Also, the full width at half maximum of the bottom transmittance at the reference transmittance tends to be smaller in a metal region 15 containing particulate metal than in a metal region 15 that does not contain particulate metal. By being able to adjust the transmittance bottom wavelength and the full width at half maximum of the bottom transmittance, it is possible to prevent light in a specific wavelength range from being transmitted compared to light in other wavelength ranges.

[0048] When adjusting the full width at half maximum of the bottom transmittance to be narrow, it is preferable that the proportion of particulate metal in the area where the metal region 15 is formed be 10% or more and 60% or less of the area of ​​the region. By satisfying this proportion, the effect of narrowing the full width at half maximum of the bottom transmittance can be sufficiently achieved compared to a metal region 15 that does not contain particulate metal. Alternatively, the transmittance of wavelengths other than the transmittance bottom wavelength can be increased. Note that the proportion of particulate metal in the area where the metal region 15 is formed to the area of ​​the region can be measured by image processing an SEM photograph (scanning electron microscope photograph) of the metal region 15.

[0049] When the metal region 15 contains particulate metal, the particle diameter of the metal is preferably 200 nm or less, more preferably 50 nm or less. When the metal region 15 contains particulate metal, the particle diameter of the metal is preferably one-third or less, more preferably one-tenth or less, of the wavelength included in the wavelength range of the full width at half maximum of the bottom transmittance of the metal region 15. When the metal region 15 contains particulate metal, the particle diameter of the metal is preferably one-third or less, more preferably one-tenth or less, of the bottom wavelength of the transmittance of the metal region 15. By setting the particle diameter of the metal in this manner, it is possible to absorb light in a specific wavelength range and suppress absorption of light in other wavelength ranges. For example, it is possible to narrow the full width at half maximum of the bottom transmittance and increase the transmittance of wavelengths other than the bottom wavelength of the transmittance. As a result, it is possible to suppress a decrease in the amount of light (luminous efficiency) emitted from the metal region 15.

[0050] When the metal region 15 contains particulate metal, the particulate metal preferably has a maximum length in the direction perpendicular to the surface on which the metal region 15 is provided of 1 nm to 100 nm, and more preferably 40 nm to 60 nm. By setting the particle diameter of the metal in this manner, it is possible to absorb light in a specific wavelength range and suppress absorption of light in other wavelength ranges. For example, it is possible to narrow the full width at half maximum of the bottom transmittance and increase the transmittance of wavelengths other than the bottom transmittance wavelength. As a result, it is possible to suppress a decrease in the amount of light (luminous efficiency) emitted from the metal region 15.

[0051] The metal forming the metal region 15 can be appropriately selected taking into consideration the absorption peak wavelength specific to the metal. By selecting a material whose absorption peak wavelength is longer than the desired transmittance bottom wavelength, the proportion of particulate metal contained can be adjusted to match the absorption peak wavelength of the metal region 15 to the desired transmittance bottom wavelength.

[0052] For example, using gold as the material, it is possible to form a metal region 15 having a transmittance bottom wavelength in the wavelength range of 500 nm to 600 nm and a bottom transmittance full width at half maximum of 20 nm to 130 nm. Also, using gold as the material, it is possible to form a metal region 15 having a transmittance bottom wavelength in the wavelength range of 520 nm to 580 nm and a bottom transmittance full width at half maximum of 20 nm to 100 nm. Also, using gold as the material, it is possible to form a metal region 15 having a transmittance bottom wavelength in the wavelength range of 520 nm to 550 nm and a bottom transmittance full width at half maximum of 20 nm to 80 nm.

[0053] (Translucent member 10) The metal region 15 is formed at least on the upper surface 11a of the light transmitting portion 11, which is the light exit surface. The metal region 15 may extend from the upper surface 11a of the light transmitting portion 11 to the upper surface 12a of the light reflecting portion 12. The metal region 15 may be formed on the entire upper surface 11a of the light transmitting portion 11 and the upper surface 12a of the light reflecting portion 12 (i.e., the entire upper surface of the composite member 13).

[0054] In the light-transmitting member 10, the upper surface 11a of the light-transmitting portion 11 on which the metal region 15 is formed is the light exit side, and the lower surface 11b of the light-transmitting portion 11 is the light entrance side. That is, light that enters the light-transmitting portion 11 is emitted via the metal region 15. Note that some of the light may also be incident on the lower surface 12b of the light-reflecting portion 12.

[0055] The light reflecting portion 12 reflects light traveling from the light transmitting portion 11 toward the light reflecting portion 12 at its inner surface 12c. The light traveling from the light transmitting portion 11 toward the light reflecting portion 12 is light that has entered the light transmitting portion 11. When the light transmitting portion 11 is a wavelength converting portion having a phosphor, the light reflecting portion 12 reflects light that has entered the light transmitting portion 11 or light whose wavelength has been converted by the light transmitting portion 11 at its inner surface 12c. The light reflecting portion 12 is preferably formed from a material with high thermal conductivity that can dissipate heat generated by the light transmitting portion 11. The light reflecting portion 12 can be formed, for example, from aluminum oxide (Al2O3), a ceramic material with high thermal conductivity.

[0056] In the light-transmitting member 10, when light in the wavelength range of 400 nm or more and 760 nm or less is incident on the light-transmitting portion 11, the metal region 15 absorbs, for example, light with a wavelength of 500 nm or more and 600 nm or less of the incident light. That is, the light-transmitting portion 11 on which the metal region 15 is formed reduces the proportion of light in the wavelength range of 500 nm or more and 600 nm or less in the total light in the wavelength range of 400 nm or more and 760 nm or less, compared to when light containing at least a wavelength of 500 nm or more and 600 nm or less passes through the light-transmitting portion 11 from which the metal region 15 is removed.

[0057] The light-transmitting member 10 may have a film other than the metal region 15. For example, a light-shielding film made of metal or the like may be formed on the metal region 15 formed on the upper surface 12a of the light-reflecting portion 12. The light-shielding film may be formed to a thickness of, for example, 50 nm or more and 500 nm or less. By providing the light-shielding film, it is possible to suppress leakage of light from other than the metal region 15 formed on the upper surface 11a of the light-transmitting portion 11, which is the light-emitting surface. Alternatively, the metal region 15 may be provided on the light-shielding film.

[0058] (Method for manufacturing the light-transmitting member 10) 3 and 4 are diagrams illustrating a method for manufacturing a light-transmitting member according to the first embodiment. First, as shown in FIG. 3, a composite member 13 having a light-transmitting portion 11 and a light-reflecting portion 12 is prepared. The composite member 13 can be prepared, for example, by manufacturing the composite member 13 from the light-transmitting portion 11 and the light-reflecting portion 12. Alternatively, instead of manufacturing the composite member 13, the composite member 13 may be procured and prepared.

[0059] When manufacturing the composite member 13, the composite member 13 can be manufactured, for example, by bonding the side surface 11c of the light-transmitting portion 11 and the inner surface 12c of the light-reflecting portion 12 with an adhesive. Alternatively, the composite member 13 can be formed, for example, by integrally sintering the light-transmitting portion 11 and the light-reflecting portion 12. In this case, for example, the powder material that forms the sintered light-transmitting portion 11 and the light-reflecting portion 12 can be integrally molded and sintered to form the composite member 13. For sintering, for example, atmospheric sintering, spark plasma sintering (SPS), hot press sintering (HP), etc. can be used.

[0060] Next, as shown in FIG. 4, a metal region 15 is formed at least on the upper surface 11a of the light-transmitting portion 11. To form the metal region 15, a metal film having a thickness of 1 nm to 10 nm is formed. The metal region 15 can be a metal film or a granular metal. The metal forming the metal film is, for example, gold. The metal to be selected can be determined based on the transmittance characteristics of the metal and the wavelength range in which the transmittance is desired to be lower than other wavelength ranges. The transmittance characteristics of the metal here are not limited to the transmittance characteristics of a thin film of the metal alone, but also include the transmittance characteristics when the metal is subjected to a heat treatment. An appropriate metal can be selected. The metal film can be formed over the entire upper surface 11a of the light-transmitting portion 11 and the upper surface 12a of the light-reflecting portion 12. The metal film can be formed, for example, by sputtering. At this stage, the metal film is formed continuously, not in a granular form. After the metal film is formed, it is heated. The step of heating the metal film granulates the metal contained in the metal film. That is, the step of heating the metal film forms metal region 15 containing granulated metal. The step of heating the metal film granulates the metal contained in the metal film, so that, for example, in the region where metal region 15 is formed, the proportion of the granular material relative to the area of ​​the region is 10% or more and 60% or less. This completes light-transmitting member 10.

[0061] When the metal contained in the metal film is granulated, the metal film is heated at a temperature of 500°C or higher and 1100°C or lower. Furthermore, from the viewpoint of increasing the overall transmittance in the wavelength range of 400nm or higher and 760nm or lower, it is preferable to heat the metal film at a temperature of 900°C or higher and 1100°C or lower. Furthermore, the heat treatment is preferably carried out in an air atmosphere. Furthermore, the heat treatment is preferably carried out for about 1 hour. Furthermore, the heat treatment is preferably carried out for no more than 10 hours in an air atmosphere. This allows for a good granulation state to be achieved. Note that the heating temperatures listed here are temperature conditions at atmospheric pressure.

[0062] 3, only the light transmitting portion 11 may be prepared, and the metal film may be formed on the upper surface 11a of the light transmitting portion 11 and then heated in the step of Fig. 4. In this case, a light-transmitting member 10 having the light transmitting portion 11 and the metal region 15 but not the light reflecting portion 12 is produced.

[0063] (Light absorption of metal region 15) 5A to 9B are SEM photographs showing the graining of the metal forming the metal region. Here, an example is shown in which the metal forming the metal film is gold. FIGS. 5A and 5B are SEM photographs of a metal film formed to a thickness of 1 nm before heating. FIGS. 6A and 6B are SEM photographs of a metal film formed to a thickness of 1 nm after heating. FIGS. 7A and 7B are SEM photographs of a metal film formed to a thickness of 2 nm after heating. FIGS. 8A and 8B are SEM photographs of a metal film formed to a thickness of 3 nm after heating. FIGS. 9A and 9B are SEM photographs of a metal film formed to a thickness of 5 nm after heating. Note that FIGS. 5A, 6A, 7A, 8A, to 9A show the surface on which the film is formed, while FIGS. 5B, 6B, 7B, 8B, to 9B show cross-sectional views. The heating conditions for the metal films shown in FIGS. 6A to 9B are 1000° C. for 1 hour (1 hour) in an air atmosphere and at atmospheric pressure.

[0064] From Figure 5A, it can be seen that the metal film before heating is formed continuously, not in a particulate form. In other words, before heating, it is a film-like metal region. Furthermore, as shown in Figures 6A to 9A, by heating at 1000°C for 1 hour in an air atmosphere and at atmospheric pressure, the metal (gold in this case) that forms the metal film becomes particulate. Furthermore, the thicker the metal film is formed, the greater the number of particles. Furthermore, when the thickness of the metal film is 3 μm or more, the size of the particles tends to increase. Note that the heating temperature does not have to be 1000°C; the metal that forms the metal region can be particulate by heating the metal film at a temperature of 900°C to 1100°C.

[0065] 10 to 13 are diagrams illustrating the change in linear transmittance before and after heating of metal films with different film thicknesses. Here, an example is shown in which the metal forming the metal film is gold. FIG. 10 is a diagram illustrating the change in linear transmittance before and after heating of a metal film with a film thickness of 1 [nm]. FIG. 11 is a diagram illustrating the change in linear transmittance before and after heating of a metal film with a film thickness of 2 [nm]. FIG. 12 is a diagram illustrating the change in linear transmittance before and after heating of a metal film with a film thickness of 3 [nm]. FIG. 13 is a diagram illustrating the change in linear transmittance before and after heating of a metal film with a film thickness of 5 [nm].

[0066] 10 to 13, the measurement samples were made of a sapphire plate with a thickness of approximately 400 μm, mirror-finished on both sides, on one side of which a metal film (gold film) of a predetermined thickness (1 nm, 2 nm, 3 nm, 5 nm) was formed. The linear transmittance was measured before and after heating for each sample with a different metal film thickness, and the results are shown in FIGS. 10 to 13. In FIGS. 10 to 13, "Sapphire" indicates the linear transmittance of sapphire without a metal film formed thereon, and "After film formation" indicates the linear transmittance of the sample before heating. The heating conditions were 1000°C for 1 hour in an air atmosphere and at atmospheric pressure.

[0067] 10 to 13, for all film thicknesses of 1 nm, 2 nm, 3 nm, and 5 nm, the transmittance bottom wavelength of the metal region (particulate distribution metal) after heating is shifted to the short wavelength side compared to the metal region (film-like metal) before heating, and the transmittance bottom wavelength is in the wavelength range of 500 nm to 600 nm. The amount of shift to the short wavelength side of the transmittance bottom wavelength of the metal region before and after heating tends to increase as the film thickness of the metal film before heating increases.

[0068] For example, when the thickness of the metal film before heating is 1 nm, as shown in FIG. 10B, the transmittance bottom wavelength of the metal region before heating is approximately 580 nm. As shown in FIG. 10C, the transmittance bottom wavelength of the metal region after heating is approximately 530 nm, with a shift of approximately 50 nm toward the short wavelength side. Also, when the thickness of the metal film before heating is 2 nm, as shown in FIG. 11B, the transmittance bottom wavelength of the metal region before heating is approximately 620 nm. As shown in FIG. 11C, the transmittance bottom wavelength of the metal region after heating is approximately 530 nm, with a shift of approximately 90 nm toward the short wavelength side. Also, when the thickness of the metal film before heating is 3 nm, as shown in FIG. 12B, the transmittance bottom wavelength of the metal region before heating is approximately 700 nm. As shown in FIG. 12C, the transmittance bottom wavelength of the metal region after heating is approximately 540 nm, with a shift of approximately 160 nm toward the short wavelength side. Furthermore, when the thickness of the metal film before heating is 5 nm, as shown in FIG. 13B, the transmittance bottom wavelength of the metal region before heating is 800 nm or more, and as shown in FIG. 13C, the transmittance bottom wavelength of the metal region after heating is approximately 580 nm, and the amount of shift of the transmittance bottom wavelength to the short wavelength side is 220 nm or more.

[0069] Furthermore, the linear transmittance at the bottom wavelength of the metal region after heating, i.e., the bottom transmittance, tends to decrease as the thickness of the metal region before heating increases. For example, as shown in FIG. 10A, the linear transmittance of sapphire is approximately 85%. As shown in FIGS. 10A and 10C, when the thickness of the metal film before heating is 1 nm, the bottom transmittance of the sapphire on which the metal region is formed after heating is approximately 79%, so the bottom transmittance of the metal region after heating is approximately 93%, and the pseudo-bottom transmittance is approximately 94%. Also, as shown in FIGS. 11A and 11C, when the thickness of the metal film before heating is 2 nm, the bottom transmittance of the sapphire on which the metal region is formed after heating is approximately 73%, so the bottom transmittance of the metal region after heating is approximately 86%, and the pseudo-bottom transmittance is approximately 88%. 12A and 12C, when the thickness of the metal film before heating is 3 nm, the bottom transmittance of the sapphire on which the metal region is formed after heating is approximately 66%, so the bottom transmittance of the metal region after heating is approximately 78%, and the pseudo-bottom transmittance is approximately 81%. Also, when the thickness of the metal film before heating is 5 nm, the bottom transmittance of the sapphire on which the metal region is formed after heating is approximately 40%, so the bottom transmittance of the metal region after heating is approximately 47%, and the pseudo-bottom transmittance is approximately 55%.

[0070] Furthermore, the full width at half maximum of the bottom transmittance tends to increase as the thickness of the metal film before heating increases. For example, as shown in Figures 10A and 10C, when the thickness of the metal film before heating is 1 nm, the full width at half maximum of the bottom transmittance or pseudo-bottom transmittance of the metal region after heating is approximately 70 nm. As shown in Figures 11A and 11C, when the thickness of the metal film before heating is 2 nm, the full width at half maximum of the bottom transmittance or pseudo-bottom transmittance of the metal region after heating is approximately 70 nm. As shown in Figures 12A and 12C, when the thickness of the metal film before heating is 3 nm, the full width at half maximum of the bottom transmittance or pseudo-bottom transmittance of the metal region after heating is approximately 80 nm. As shown in Figures 13A and 13C, when the thickness of the metal film before heating is 5 nm, the full width at half maximum of the bottom transmittance or pseudo-bottom transmittance of the metal region after heating is approximately 140 nm.

[0071] In this way, by heating the metal film, the metal forming the metal region is granulated, and the transmittance bottom wavelength of the heated metal region is shifted to the short wavelength side compared to the metal region before heating, allowing the transmittance bottom wavelength of the heated metal region to fall within a predetermined wavelength range. Furthermore, the amount of shift in the transmittance bottom wavelength to the short wavelength side and the full width at half maximum of the bottom transmittance can be selected by the film thickness of the metal film before heating. By utilizing this characteristic, the chromaticity point of light emitted from the light-emitting surface of the light-transmitting member 10 can be shifted, as described below.

[0072] 1 etc., if the metal forming the metal region 15 is gold, the gold will be turned into particles through a heating process, and the transmittance bottom wavelength will fall within the wavelength range of 500 nm to 600 nm. In this case, when light in the wavelength range of 400 nm to 760 nm is incident from the lower surface 11b side of the light-transmitting portion 11, the light in the wavelength range of 500 nm to 600 nm contained in the incident light will mainly be absorbed.

[0073] This reduces the proportion of light in the wavelength range of 500 nm to 600 nm in the total light in the wavelength range of 400 nm to 760 nm. As a result, the chromaticity point of the light emitted from the light-emitting surface of the translucent member 10 can be shifted to the longer wavelength side compared to when the metal region 15 is not formed. In other words, the translucent member 10 can emit light with adjusted chromaticity.

[0074] 1 and other figures, the light-transmitting portion 11 may be a wavelength conversion portion having YAG as a phosphor, and laser light having an emission peak wavelength in the range of 420 nm to 480 nm may be incident on the lower surface 11b of the light-transmitting portion 11. In this case, white light is incident on the incident surface of the metal region 15 (or white light is emitted from the surface on which the metal region 15 is formed), and the metal region 15 mainly absorbs light in the wavelength range of 500 nm to 600 nm (green component) contained in the incident light. On the other hand, most of the blue and red components are transmitted through the metal region 15, so the green component of the white light is reduced, and the light emitted from the exit surface of the light-transmitting member 10 (or the exit surface of the metal region 15) can be adjusted to have a strong reddish tint.

[0075] In particular, when the thickness of the metal film is 1 nm or more and 3 nm or less, the amount of shift of the transmittance bottom wavelength to the short wavelength side due to heating is large, the full width at half maximum of the bottom transmittance also becomes an appropriate value, and much light in the wavelength range of 500 nm to 600 nm is absorbed. Therefore, a metal film thickness of 1 nm or more and 3 nm or less is suitable for obtaining white light with a strong reddish tint.

[0076] Furthermore, since the transmittance bottom wavelength and the full width at half maximum of the bottom transmittance change depending on the film thickness of the metal film before heating, the color of the light emitted from the exit surface of the light-transmitting member 10 (the exit surface of the metal region 15) can be changed by changing the film thickness of the metal film before heating.

[0077] When the light-transmitting section 11 is a wavelength conversion section having a phosphor and laser light is incident on the light-transmitting section 11, the chromaticity point of the light emitted from the light-transmitting member 10 can be adjusted on a straight line on a chromaticity diagram that connects the chromaticity point of the laser light and the chromaticity point of the emitted color of the phosphor. By adding the adjustment of the chromaticity point by the light absorption of the metal region 15 to this, chromaticity adjustment becomes possible even in areas that deviate from the straight line, thereby improving the degree of freedom in adjusting the chromaticity point.

[0078] When the light-transmitting portion 11 is formed from a sintered body, a heat treatment is required, so it is possible to form it without using a phosphor that is sensitive to heat. For example, if the light-transmitting portion 11 is formed solely from YAG phosphor, increasing the amount of Ce or Gd contained in the phosphor is one way to shift the chromaticity point toward the longer wavelength side. However, increasing the amount of Ce or Gd contained in the phosphor may impair the linearity of the temperature characteristics of the wavelength conversion portion. For example, a temperature characteristic that is linear in the low temperature range becomes nonlinear in the high temperature range. This change in characteristics makes it difficult to control the output. In contrast, a method of shifting the chromaticity point toward the longer wavelength side by utilizing the absorption of the metal region 15 makes it possible to adjust the chromaticity point without impairing the linearity of the temperature characteristics of the wavelength conversion portion.

[0079] Furthermore, when the metal forming the metal region 15 is particulate, the particulate metal scatters the incident laser light. As a result, in the light emitted from the emission surface of the light-transmitting member 10 (the emission surface of the metal region 15), the portion where the color of the laser light (for example, blue) is strong is weakened, and color unevenness and / or brightness unevenness in the light emitted from the emission surface is reduced.

[0080] Note that, in forming the metal region 15, it is not necessary to heat the metal film to granulate it. For example, in FIGS. 10 and 11, the metal film before heating also has a transmittance bottom wavelength at a predetermined wavelength and a predetermined full width at half maximum of the bottom transmittance. Therefore, even when using the metal film before heating shown in FIGS. 10 and 11, it is possible to reduce the proportion of light in a predetermined wavelength range and shift the chromaticity point of light emitted from the light-emitting surface of the light-transmitting member 10 compared to when no metal film is formed. When there is a demand to shift the transmittance bottom wavelength to a shorter wavelength or to narrow the full width at half maximum of the bottom transmittance, it is effective to heat the metal film to granulate it.

[0081] <Modification 1 of the First Embodiment> In Modification 1 of the first embodiment, an example of a light-transmitting member having a light-transmitting protective film that covers a metal film is shown. Note that in Modification 1 of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0082] Fig. 14 is a cross-sectional view illustrating a light-transmitting member according to Modification 1 of the first embodiment. As shown in Fig. 14, the light-transmitting member 10A has a composite member 13, a metal region 15, and a protective film 16. That is, the light-transmitting member 10A differs from the light-transmitting member 10 (see Figs. 1, 2, etc.) in that the protective film 16 is formed on the light-emitting surface side of the metal region 15.

[0083] (Protective film 16) The protective film 16 is a light-transmitting film. That is, the protective film 16 has a transmittance of 80% or more for incident light. The protective film 16 preferably has a transmittance of 90% or more for incident light, and more preferably has a transmittance of 95% or more. The protective film 16 has a thickness of, for example, 10 nm or more and 100 nm or less. If the protective film 16 has a thickness of 10 nm or more, the object can be sufficiently protected. If the protective film 16 has a thickness of 100 nm or less, the transmittance of incident light can be sufficiently high.

[0084] The protective film 16 is, for example, a silicon oxide film. Instead of a silicon oxide film, aluminum oxide, magnesium oxide, zirconium oxide, or the like may be used as the protective film 16.

[0085] (Translucent member 10A) In the light-transmitting member 10A, the protective film 16 is formed on the light-emitting surface of the metal region 15. The thickness of the protective film 16 is preferably thicker than the thickness of the metal region 15 or the maximum length in the direction perpendicular to the light-emitting surface. In the light-transmitting member 10A, the upper surface 11a of the light-transmitting portion 11 on which the metal region 15 and the protective film 16 are formed is the light-emitting side, and the lower surface 11b of the light-transmitting portion 11 is the light-incident side. In other words, light that enters the light-transmitting portion 11 is emitted via the metal region 15 and the protective film 16.

[0086] To form the protective film 16, for example, in the step of forming the metal film of the first embodiment, a protective film is further formed on the metal provided on the emission surface of the light transmitting portion 11 and then heated. If the protective film 16 is, for example, a silicon oxide film, a silicon film is formed as the protective film 16 and then heated in the step of forming the protective film 16. The silicon film reacts with oxygen in the air during heating and becomes a light-transmitting silicon oxide film.

[0087] 15 and 16 are diagrams illustrating the change in linear transmittance before and after heating for protective films with different film thicknesses. Here, an example is shown in which the metal forming the metal film is gold, and the protective film after heating is a silicon oxide film. FIG. 15 is a diagram illustrating the change in linear transmittance before and after heating when a protective film is formed on a metal film with a film thickness of 1 nm. FIG. 16 is a diagram illustrating the change in linear transmittance before and after heating when a protective film is formed on a metal film with a film thickness of 2 nm. In FIGS. 15 and 16, the protective film formed on the metal film before heating is silicon with a film thickness of 50 nm or 100 nm.

[0088] 15 and 16, the measurement samples were made by forming a metal film (gold film) of a predetermined thickness (1 nm, 2 nm) on one side of a sapphire plate with a thickness of approximately 400 μm and mirror-finished on both sides, and then forming a protective film (silicon film) of a predetermined thickness (50 nm, 100 nm) on the metal film. For each sample with different thicknesses of the metal film and protective film, the linear transmittance of the metal film and protective film was measured before and after heating, and the results are shown in FIGS. 15 and 16. The heating conditions were 1000°C for 1 hour in an air atmosphere and at atmospheric pressure.

[0089] As shown in Figures 15 and 16, regardless of the thickness of the metal film, the metal film and protective film have low linear transmittance before heating. However, after heating, the linear transmittance is almost the same as that without the protective film, as shown in Figures 10 and 11. This is because the silicon film that forms the protective film reacts with oxygen in the air during heating, turning into a translucent silicon oxide film, whose refractive index is lower than that of sapphire. Comparing Figures 15 and 16 with Figures 10 and 11, it can be seen that the linear transmittance of the silicon oxide protective film is 95% or higher.

[0090] It is possible to form a silicon oxide film as a protective film on the metal film before heating, but in this case, there is a risk that the silicon oxide film will crack or peel off due to heating. By forming a silicon film as a protective film on the metal film and then converting it into a silicon oxide film by heating, such problems can be avoided.

[0091] Furthermore, by forming a silicon film on a metal film and then heating it, it is possible to intentionally diffuse the metal into the silicon film, which has the effect of improving the uniformity of the grain size of the metal grained in the metal region.

[0092] In this way, the translucent member 10A has a translucent protective film 16 that covers the metal region 15, thereby protecting the metal region 15 without impairing the translucency of the translucent member 10A, and preventing the metal region 15 from peeling off from the composite member 13 or being damaged.

[0093] <Modification 2 of the First Embodiment> Modification 2 of the first embodiment shows an example of a light-transmitting member having a structure different from that of Embodiment 1. Note that in Modification 2 of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0094] 17 is a cross-sectional view illustrating a light-transmitting member according to Modification 2 of Embodiment 1. As shown in FIG. 17, a light-transmitting member 10B has a composite member 13B, a metal region 15, and a second light-transmitting portion 19.

[0095] (Composite member 13B) The composite member 13B has a light transmitting portion 17 and a light reflecting portion 18. However, the light reflecting portion 18 is not an essential component and is provided as needed.

[0096] The light transmitting portion 17 has the same material and function as the light transmitting portion 11, but has a different shape from the light transmitting portion 11. The light transmitting portion 17 has an upper surface 17a, a lower surface 17b opposite the upper surface 17a, and a side surface 17c intersecting with the upper surface 17a and the lower surface 17b. The side surface 17c connects the outer edge of the upper surface 17a to the outer edge of the lower surface 17b.

[0097] The light transmitting portion 17 has, for example, an inverted truncated cone shape. In this case, the upper surface 17a of the light transmitting portion 17 is circular, the lower surface 17b is circular with a smaller diameter than the upper surface 17a, and the side surface 17c is a single curved surface.

[0098] The light reflecting portion 18 is made of the same material and has the same function as the light reflecting portion 12, but has a different shape from the light reflecting portion 12. The light reflecting portion 18 is, for example, a frame-shaped member having an opening. The light reflecting portion 18 has an upper surface 18a, a lower surface 18b opposite the upper surface 18a, an inner side surface 18c connecting the inner edge of the upper surface 18a to the inner edge of the lower surface 18b, and an outer side surface 18d connecting the outer edge of the upper surface 18a to the outer edge of the lower surface 18b.

[0099] The opening of the light reflecting portion 18 is, for example, a through-hole in the shape of an inverted truncated cone. In this case, the inner edge of the upper surface 18a of the light reflecting portion 18 is circular, the inner edge of the lower surface 18b is circular with a smaller diameter than the inner edge of the upper surface 18a, and the inner surface 18c is a single curved surface. The outer edges of the upper surface 18a and the lower surface 18b of the light reflecting portion 18 are, for example, rectangular. In this case, the light reflecting portion 18 has four rectangular outer surfaces 18d.

[0100] In the composite member 13B, the light reflecting portion 18 is thicker than the light transmitting portion 17, and the light transmitting portion 17 is disposed near the center of the opening of the light reflecting portion 18 in the thickness direction. The light transmitting portion 17 is fixed to the inner surface 18c of the light reflecting portion 18 by, for example, a light-transmitting adhesive. For example, glass can be used as the light-transmitting adhesive. Within the opening of the light reflecting portion 18, a space 18x is formed below the light transmitting portion 17.

[0101] (Second light transmission section 19) The second light transmitting portion 19 has an upper surface 19a, a lower surface 19b opposite to the upper surface 19a, and a side surface 19c intersecting with the upper surface 19a and the lower surface 19b. The side surface 19c connects the outer edge of the upper surface 19a to the outer edge of the lower surface 19b.

[0102] The second light transmitting portion 19 has, for example, an inverted truncated cone shape. In this case, the upper surface 19a of the second light transmitting portion 19 is circular, the lower surface 19b is circular with a smaller diameter than the upper surface 19a, and the side surface 19c is a single curved surface. The second light transmitting portion is made of a light-transmitting material. The material of the second light transmitting portion is, for example, glass.

[0103] (Translucent member 10B) The light-transmitting member 10B has the same function as the light-transmitting member 10, but a different shape from the light-transmitting member 10. The metal region 15 is formed on the upper surface 17a of the light-transmitting portion 17 and on the inner surface 18c of the light-reflecting portion 18, in a portion located above the light-transmitting portion 17. The metal region 15 also contacts the lower surface 19b and side surface 19c of the second light-transmitting portion 19.

[0104] In the light-transmitting member 10B, the upper surface 17a of the light-transmitting portion 17 on which the metal region 15 is formed is the light exit side, and the lower surface 17b of the light-transmitting portion 17 is the light entrance side. Light that enters the light-transmitting portion 17 passes through the metal region 15 and then exits via the second light-transmitting portion 19. Note that some of the light may also enter the lower surface 18b of the light-reflecting portion 18. The second light-transmitting portion 19 has the function of improving the strength of the light-transmitting member 10B.

[0105] Light reflecting portion 18 reflects light traveling from light transmitting portion 17 toward light reflecting portion 18 at inner surface 18c. Light traveling from light transmitting portion 17 toward light reflecting portion 18 is light that has entered light transmitting portion 17. When light transmitting portion 17 is a wavelength converting portion having a phosphor, light reflecting portion 18 reflects light that has entered light transmitting portion 17 or light whose wavelength has been converted by light transmitting portion 17 at inner surface 18c.

[0106] (Method for manufacturing the light-transmitting member 10B) To manufacture the light-transmitting member 10B, first, a composite member 13B is prepared. The composite member 13B can be prepared, for example, by manufacturing the composite member 13B from a light-transmitting portion 11 and a light-reflecting portion 12. Specifically, for example, a light-reflecting portion 18 having a truncated cone-shaped opening is prepared, and the side surface 17c of the light-transmitting portion 17 is bonded to the inner surface 18c of the light-reflecting portion 18 via a light-transmitting adhesive. For example, glass is used as the light-transmitting adhesive, and the side surface 17c of the light-transmitting portion 17 is fused to the inner surface 18c of the light-reflecting portion 18. Alternatively, instead of manufacturing the composite member 13B, the composite member 13B may be procured and prepared.

[0107] Next, a metal film is formed on the upper surface 17a of the light-transmitting portion 17, on the portion of the inner surface 18c of the light-reflecting portion 18 that is located above the light-transmitting portion 17, and on the upper surface 18a of the light-reflecting portion 18. The metal that forms the metal film is, for example, gold. The metal film can be formed by, for example, a sputtering method. At this point, the metal film is formed continuously, not in a granular form.

[0108] After forming the metal film, the metal film is heated. The metal contained in the metal film is granulated by the process of heating the metal film. That is, the process of heating the metal film forms metal region 15 containing granulated metal. The process of heating the metal film granulates the metal contained in the metal film, and for example, in the region where metal region 15 is formed, the proportion of granular material relative to the area of ​​the region is 10% or more and 60% or less.

[0109] Next, a light-transmitting material (e.g., glass) that will become the second light-transmitting portion 19 is placed on the metal region 15 located within the opening of the light-reflecting portion 18. The light-transmitting material is then heated to melt it, and then hardened to form the second light-transmitting portion 19. At this point, the second light-transmitting portion 19 protrudes upward from the metal region 15 that covers the upper surface 18a of the light-reflecting portion 18.

[0110] Next, the second light transmitting portion 19 protruding upward from the metal region 15 covering the upper surface 18a of the light reflecting portion 18, and the metal region 15 covering the upper surface 18a of the light reflecting portion 18 are polished and removed to make the upper surface 18a side of the light reflecting portion 18 a flat. The upper surface 18a of the light reflecting portion 18 is, for example, flush with the upper surface of the second light transmitting portion 19. This completes the light-transmitting member 10B.

[0111] In the light-transmitting member 10B, heating the metal film also causes the metal forming the metal film to become particles. The transmittance bottom wavelength of the heated metal region shifts toward the shorter wavelength side compared to the metal region before heating, allowing the transmittance bottom wavelength of the heated metal region to fall within a predetermined wavelength range. The amount of the transmittance bottom wavelength shift toward the shorter wavelength side and the full width at half maximum of the bottom transmittance can be selected by adjusting the thickness of the metal film before heating. By utilizing this characteristic, the chromaticity point of light emitted from the light-emitting surface of the light-transmitting member 10B can be shifted, similar to the light-transmitting member 10. In the light-transmitting member 10B, the metal region 15 is not formed on the upper surface 18a of the light-reflecting portion 18, and thus light with a shifted chromaticity point can be emitted only from the second light-transmitting portion 19.

[0112] Second Embodiment The second embodiment shows an example of an optical member using the light-transmitting member according to the first embodiment. Note that in the second embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0113] Fig. 18 is a perspective view illustrating an optical member according to a second embodiment. Fig. 19 is a cross-sectional view taken along line XIX-XIX in Fig. 18, illustrating the optical member according to the second embodiment. As shown in Figs. 18 and 19, an optical member 20 includes a light-transmitting member 10 and a plate-shaped member 21.

[0114] Each component of the optical member 20 will be described.

[0115] (Plate-shaped member 21) The plate-shaped member 21 is a light-transmitting member. The plate-shaped member 21 has an upper surface 21a, a lower surface 21b opposite the upper surface 21a, and side surfaces 21c intersecting with the upper surface 21a and the lower surface 21b. The side surfaces 21c connect the outer edges of the upper surface 21a and the lower surface 21b. The plate-shaped member 21 is, for example, a rectangular parallelepiped or a cube. In this case, the upper surface 21a and the lower surface 21b of the plate-shaped member 21 are both rectangular, and the plate-shaped member 21 has four rectangular side surfaces 21c.

[0116] However, the plate-like member 21 is not limited to a rectangular parallelepiped or a cube. That is, the planar shape of the plate-like member 21 is not limited to a rectangle, and can be any shape such as a circle, an ellipse, or a polygon.

[0117] The plate-shaped member 21 can be formed using sapphire as the main material. Sapphire is a material with relatively high transmittance and strength. In addition to sapphire, the main material may be a light-transmitting material including, for example, quartz, silicon carbide, or glass.

[0118] (Optical member 20) In the optical member 20, the surface of the light-transmitting member 10 on which the metal region 15 is not formed is joined to the upper surface 21a of the plate-shaped member 21. That is, the plate-shaped member 21 is disposed on the lower surface 11b side of the light-transmitting portion 11 and the lower surface 12b side of the light-reflecting portion 12. When the base material of the plate-shaped member 21 is sapphire, sapphire is a material with relatively high thermal conductivity, and therefore can dissipate heat generated in the light-transmitting member 10.

[0119] Because the plate-shaped member 21 is translucent, light incident on the lower surface 21b side of the plate-shaped member 21 reaches the metal region 15 via the light-transmitting portion 11 and is emitted from the metal region 15 side. Therefore, by the metal region 15 absorbing light within a specific wavelength range, the chromaticity point of the light emitted from the optical member 20 can be shifted to the longer wavelength side compared to when the metal region 15 is not formed. In other words, the optical member 20 can emit light with adjusted chromaticity.

[0120] Third Embodiment The third embodiment shows an example of a light emitting device using the optical member according to the second embodiment. Note that in the third embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0121] Fig. 20 is a perspective view illustrating a light emitting device according to a third embodiment. Fig. 21 is a cross-sectional view taken along line XXI-XXI in Fig. 20 illustrating the light emitting device according to the third embodiment. Fig. 22 is a perspective view illustrating the light emitting device according to the third embodiment from which optical members have been further removed. Fig. 23 is a plan view illustrating the light emitting device according to the third embodiment from which optical members have been further removed.

[0122] 20 to 23, the light emitting device 200 has an optical member 20, a base 210, a light emitting element 220, a submount 230, a light reflecting member 240, a protective element 250, a temperature measuring element 260, wiring 270, and a light blocking member 280. The light emitting device 200 only needs to have at least the optical member 20, the base 210, and the light emitting element 220. The light emitting device 200 may also have a light-transmitting member 10 instead of the optical member 20.

[0123] Each component of the light emitting device 200 will be described.

[0124] (base 210) The base 210 has an upper surface 210a, a lower surface 210b, multiple inner surfaces 210c, one or multiple outer surfaces 210d, and a bottom surface 210e. The base 210 has a concave shape that is recessed from the upper surface 210a to the lower surface 210b. The base 210 has a rectangular outer shape in a plan view, and the recess is formed inside this outer shape.

[0125] In addition, in a plan view, a frame is formed by one or more inner surfaces 210c that intersect with the top surface 210a. That is, the base 210 has a bottom surface 210e and a frame that forms the inner surfaces 210c that reach above the bottom surface 210e. The recess including the bottom surface 210e of the base 210 is surrounded by this frame.

[0126] The base 210 also has one or more step portions 216 on the inside of the frame. The step portion 216 is composed only of an upper surface and a side surface that intersects with the upper surface and extends downward. The one or more inner side surfaces 210c include a side surface that intersects with the upper surface 210a of the base 210 and the side surface of the step portion 216.

[0127] The base 210 can be formed, for example, primarily from ceramics. For example, aluminum nitride, silicon nitride, aluminum oxide, or silicon carbide can be used as the ceramic. Note that the base 210 is not limited to being formed from ceramics, and may be formed primarily from other insulating materials.

[0128] Furthermore, one or more metal films are provided on the bottom surface 210e of the base 210. Furthermore, one or more metal films are provided on the top surface 210a of the base 210. Furthermore, the one or more metal films provided on the bottom surface 210e include a metal film that is electrically connected to the metal film provided on the top surface 210a.

[0129] The frame of the base 210 does not have to be provided on the same plane as the bottom surface 210e. For example, the frame of the base 210 may be provided on a plane that is recessed from the bottom surface 210e. Furthermore, the base 210 does not have to be formed as an integral unit, and may be, for example, a plate-like member to which the frame is joined.

[0130] (light-emitting element 220) The light-emitting element 220 is not particularly limited as long as it is an element that emits light, and for example, a semiconductor laser element, a light-emitting diode (LED), or an organic light-emitting diode (OLED) can be used. In this embodiment, as an example, a semiconductor laser element is used as the light-emitting element 220. That is, the light-emitting element 220 in the following description is a semiconductor laser element.

[0131] The light emitting element 220 has, for example, a rectangular outer shape in a plan view. A side surface intersecting one of the two short sides of the rectangle serves as an output end surface for light emitted from the light emitting element 220. The upper and lower surfaces of the light emitting element 220 have areas larger than the output end surface.

[0132] The light (laser light) emitted from the light emitting element 220 has a spreading property and forms an elliptical far-field pattern (hereinafter referred to as "FFP") on a plane parallel to the light output end face. Here, FFP refers to the shape and light intensity distribution of the output light at a position away from the output end face.

[0133] In a plane parallel to the light emitting end face, the light emitted from the light emitting element 220 forms an elliptical FFP with the layer direction of the multiple semiconductor layers including the active layer as the minor axis and the stacking direction perpendicular to the minor axis as the major axis. The layer direction corresponding to the minor axis is called the horizontal direction of the FFP, and the stacking direction corresponding to the major axis is called the vertical direction of the FFP.

[0134] Furthermore, based on the light intensity distribution of the FFP of the light emitting element 220, 1 / e 2 Light with an intensity above this level is called the main light. The angle corresponding to the full width at half maximum of this light intensity distribution is called the divergence angle. The divergence angle of the FFP in the vertical direction is called the vertical divergence angle, and the divergence angle of the FFP in the horizontal direction is called the horizontal divergence angle.

[0135] The light emitting element 220 may have a peak wavelength of light emitted from the light emitting element 220 in the range of 320 nm to 495 nm, typically in the range of 420 nm to 480 nm. An example of such a light emitting element 220 is a semiconductor laser element containing a nitride semiconductor. Examples of nitride semiconductors that can be used include GaN, InGaN, and AlGaN. The wavelength of the light emitted from the light emitting element 220 is not limited to these.

[0136] (Submount 230) The submount 230 is, for example, rectangular parallelepiped in shape and has a bottom surface, a top surface, and side surfaces. The width of the submount 230 in the vertical direction is the smallest. The shape is not limited to a rectangular parallelepiped. The submount 230 is formed using, for example, aluminum nitride or silicon carbide, but other materials may also be used. A metal film is provided on the top surface of the submount 230.

[0137] (Light reflecting member 240) The light reflecting member 240 has a light reflecting surface 241 that reflects light. The light reflecting surface is provided with a surface that has a light reflectance of 90% or more for the peak wavelength of the irradiated light. The light reflectance here may be 100% or less.

[0138] The light reflecting member 240 also has a plurality of light reflecting surfaces 241. The plurality of light reflecting surfaces 241 include two light reflecting surfaces 241 that are all planar and inclined relative to the lower surface, with the two light reflecting surfaces 241 having different inclination angles relative to the lower surface. Neither of the two light reflecting surfaces 241 is positioned perpendicularly or parallel to the lower surface. The two light reflecting surfaces 241 are continuously connected to form a single, integrated reflective area. The shape of the light reflecting surface 241 is not limited to a planar shape, and may be, for example, a curved shape.

[0139] It is preferable to select a heat-resistant material as the main material for the light reflecting member 240, and examples of such materials include glass such as quartz or BK7 (borosilicate glass), metal such as aluminum, or Si. The light reflecting surface can be formed using a metal such as Ag or Al, or a dielectric multilayer film of Ta2O5 / SiO2, TiO2 / SiO2, or Nb2O5 / SiO2. Note that A / B indicates a multilayer film in which a film of A and a film of B are stacked in order.

[0140] (protective element 250) The protective element 250 is intended to prevent a specific element such as a light emitting element from being destroyed by an excessive current flowing through it. As the protective element 250, for example, a Zener diode made of Si can be used.

[0141] (Temperature measuring element 260) The temperature measuring element 260 is an element used as a temperature sensor for measuring the ambient temperature. For example, a thermistor can be used as the temperature measuring element 260.

[0142] (Wiring 270) The wiring 270 is used for electrical connection between the two components. For example, a metal wire can be used as the wiring 270.

[0143] (Light blocking member 280) The light blocking member 280 can be formed, for example, from a resin having light blocking properties. Here, light blocking properties refer to the property of not transmitting light, and light blocking properties may be achieved by utilizing properties such as light absorption and reflection in addition to the light blocking property. The light blocking member 280 can be formed, for example, by incorporating fillers such as a light diffusing material and / or a light absorbing material into a resin.

[0144] Examples of the resin that forms the light-shielding member 280 include epoxy resin, silicone resin, acrylate resin, urethane resin, phenol resin, and BT resin. Examples of the light-absorbing filler contained in the light-shielding member 280 include dark-colored pigments such as carbon black.

[0145] (Light emitting device 200) In the light emitting device 200, two light reflecting members 240 are disposed on the bottom surface 210e of the base 210. The lower surfaces of the two light reflecting members 240 are joined to the bottom surface 210e of the base 210. The two light reflecting members 240 are disposed, for example, symmetrically with respect to point SP (see FIG. 23). In plan view, the upper ends of the light reflecting surfaces 241 of the two light reflecting members 240 are parallel or perpendicular to the inner surface 210c or the outer surface 210d of the base 210. Note that a difference of ±5 degrees or less is permitted between the parallel and perpendicular orientations here.

[0146] A protective element 250 and a temperature measuring element 260 are disposed on the bottom surface 210e of the base 210. The protective element 250 is disposed on and bonded to the metal film on which one of the two light reflecting members 240 is disposed. The temperature measuring element 260 is disposed on and bonded to a metal film different from the metal film on which the two light reflecting members 240 are disposed.

[0147] Two submounts 230 are disposed on the bottom surface 210e of the base 210. The two submounts 230 are disposed on different metal films, and their lower surfaces are bonded to the bottom surface 210e of the base 210.

[0148] The light emitting element 220 is disposed on the bottom surface 210e of the base 210. Specifically, the light emitting element 220 is disposed on a submount 230. In the illustrated example of the light emitting device 200, the two light emitting elements 220 are disposed on the upper surfaces of different submounts 230, and the lower surfaces of the submounts 230 are joined to the bottom surface 210e of the base 210. The two light emitting elements 220 are disposed symmetrically with respect to a point SP. In other words, the point at which the two light emitting elements 220 are symmetrical and the point at which the two light reflecting members 240 are symmetrical are located at the same position. In the following description, this point SP will be referred to as the symmetrical point.

[0149] In plan view, the light-emitting elements 220 have emitting end faces that are neither parallel nor perpendicular to the inner surface 210c or the outer surface 210d of the base 210. Therefore, the emitting end faces are also neither parallel nor perpendicular to the upper end of the light-reflecting surface 241. In other words, the light-emitting elements 220 are arranged such that the emitting end faces are oblique to the inner surface 210c and the outer surface 210d of the base 210 or the upper end of the light-reflecting surface 241 in plan view.

[0150] The light emitted from the output end surface of each of the two light emitting elements 220 is irradiated onto the corresponding light reflecting member 240. The light emitting elements 220 are arranged so that at least the main part of the light is irradiated onto the light reflecting surface 241.

[0151] Furthermore, between the corresponding light emitting element 220 and light reflecting member 240, the light emitting element 220 is located farther from the symmetric point than the light reflecting member 240. Therefore, the light emitted from the light emitting element 220 travels in a direction approaching the symmetric point.

[0152] The light emitting element 220, the protection element 250, and the temperature measuring element 260 are electrically connected to a metal film provided on the bottom surface 210e of the base 210 via corresponding wiring 270. The metal film provided on the bottom surface 210e of the base 210 is used to electrically connect these elements to an external power supply. This allows these elements to be electrically connected to an external power supply via the metal film on the top surface 210a of the base 210.

[0153] The plate-like member 21 of the optical member 20 is disposed on the upper surface side of the base 210. Specifically, the outer periphery of the lower surface 21b of the plate-like member 21 is joined to the upper surface of the stepped portion 216 of the base 210. By joining the plate-like member 21 to the base 210, a closed space in which the light-emitting element 220 is disposed is formed. In this way, in the light-emitting device 200, the plate-like member 21 can serve as a lid member. Furthermore, this closed space is formed in an airtight sealed state. By being airtight sealed, it is possible to prevent organic matter and the like from collecting on the light-emitting end surface of the light-emitting element 220.

[0154] In addition, when using a light-transmitting member 10 instead of the optical member 20, for example, the light-reflecting portion 12 of the light-transmitting member 10 may be made to have an appropriate size, and the outer periphery of the lower surface 12b of the light-reflecting portion 12 may be joined to the upper surface of the step portion 216 of the base 210.

[0155] A major portion of the light emitted by the light emitting element 220 is reflected by the light reflecting surface 241 of the light reflecting member 240 and enters the plate-shaped member 21. The plate-shaped member 21 is translucent to the light emitted by the light emitting element 220. After passing through the plate-shaped member 21, the major portion of the light enters the light transmitting portion 11 of the translucent member 10 that constitutes the optical member 20.

[0156] The light-transmitting member 10 has, on its lower surface, a light entrance region where a main portion of light enters, and a peripheral region. Furthermore, the light entrance region is formed by a light-transmitting portion 11 in the light-transmitting member 10. When the light-transmitting portion 11 in the light-transmitting member 10 is a wavelength conversion portion having a phosphor, the light-transmitting portion 11 emits second light obtained by converting the first light emitted from the light-emitting element 220 into light of a different wavelength.

[0157] The first light emitted from the light-emitting element 220 or the second light wavelength-converted by the light-transmitting section 11 is emitted to the outside of the light-emitting device 200 through the metal region 15 formed on the upper surface 11a of the light-transmitting section 11. That is, the upper surface of the metal region 15 formed on the upper surface 11a of the light-transmitting section 11 serves as the emission surface of the light-emitting device 200. In the light-transmitting member 10, when the light-transmitting section 11 is a wavelength conversion section having a phosphor, the metal region 15 reduces the amount of emitted first light and increases the amount of emitted second light compared to a state in which the metal region 15 is not formed.

[0158] The light blocking member 280 is formed inside the frame formed by the upper surface 210a of the base 210. The light blocking member 280 is formed so as to fill the gap between the base 210 and the light-transmitting member 10. The light blocking member 280 can be formed, for example, by pouring a thermosetting resin and hardening it with heat. Providing the light blocking member 280 suppresses light leakage.

[0159] In the light emitting device 200, for example, the light transmitting portion 11 of the light-transmitting member 10 may contain a YAG phosphor, and the light emitting element 220 may be a semiconductor laser element that emits blue light with an emission peak wavelength in the range of 420 nm to 480 nm.

[0160] Light-emitting device 200 is equipped with translucent member 10 having metal region 15 with a transmittance bottom wavelength in a specific wavelength range, and can absorb light in the specific wavelength range that reaches metal region 15, thereby changing the chromaticity point of light emitted from light-emitting device 200. For example, if metal region 15 mainly absorbs light in the wavelength range of 500 nm to 600 nm (green component) contained in the incident light, the green component of the fluorescence mainly due to the YAG phosphor is reduced, and the light emitted from light-emitting device 200 becomes light with a relatively increased reddish tinge. In this way, by partially absorbing light of a specific wavelength without significantly impairing the overall transmittance, it is possible to emit light adjusted to a desired chromaticity.

[0161] The light emitting device 200 can be used, for example, in an in-vehicle headlight, but is not limited to this, and can also be used as a light source for lighting, a projector, a head-mounted display, a backlight for other displays, and the like.

[0162] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims. [Explanation of symbols]

[0163] 10, 10A, 10B Translucent member 11, 17 Light transmission part 11a, 12a, 17a, 18a, 21a, 210a top 11b, 12b, 17b, 18b, 21b, 210b Bottom 11c, 17c, 21c side 12, 18 Light reflecting part 12c, 18c, 210c inner surface 12d, 18d, 210d outer surface 13, 13B Composite members 15 Metal area 16 Protective film 18x space 19 Second light transmitting part 20 Optical Components 21 Plate-shaped member 200 Light-emitting device 210 base 216 Step 220 Light-emitting element 230 Submount 240 Light-reflecting member 241 Light reflective surface 250 Protection element 260 Temperature measuring element 270 Wiring 280 Light-shielding material

Claims

1. a light transmitting portion having an exit surface through which light is emitted; a metal region in the form of a film having a film thickness of 1 nm or more and 10 nm or less, formed on the light emitting surface, or a metal region in which particulate metal is dispersed, the particulate metal having a maximum length of 1 nm or more and 100 nm or less in a direction perpendicular to the light emitting surface, the light-transmitting portion has a phosphor; The light-transmitting member, wherein the phosphor is cerium-activated yttrium aluminum garnet.

2. the light transmitting portion further includes an incident surface onto which light is incident, The light-transmitting member according to claim 1 , wherein the metal region is formed only on the light-emitting surface out of the light-incident surface and the light-emitting surface.

3. The light-transmitting member according to claim 2 , wherein the incident surface is a surface opposite to the exit surface.

4. the light-transmitting portion is translucent to light in a wavelength range of 400 nm or more and 760 nm or less, 4. The light-transmitting member according to claim 1, wherein the light-transmitting portion in which the metal region is formed reduces a proportion of light in the wavelength range of 500 nm or more and 600 nm or less in all light in the wavelength range of 400 nm or more and 760 nm or less, compared to a case in which light including at least a wavelength of 500 nm or more and 600 nm or less passes through the light-transmitting portion in which the metal region is removed.

5. The light-transmitting member according to claim 1 , wherein the metal forming the metal region is gold.

6. The light-transmitting member according to claim 1 , wherein the metal region is a metal region in which metal particles having a maximum length in a direction perpendicular to the light-emitting surface of 40 nm to 60 nm are dispersed.

7. The light-transmitting member according to claim 1 , further comprising a light-transmitting protective film that covers the metal region.

8. The light-transmitting member according to claim 7 , wherein the protective film has a thickness greater than a thickness of the metal region or a maximum length in a direction perpendicular to the light-emitting surface.

9. 9. The light-transmitting member according to claim 7, wherein the protective film is a silicon oxide film.

10. The light-transmitting member according to any one of claims 1 to 9; an optical member having a light-transmitting plate-like member disposed on the incident surface side of the light transmitting portion.

11. A light-emitting element; The optical element according to claim 10 includes the light-transmitting member according to any one of claims 1 to 9, The light-emitting device is configured such that the light-transmitting member allows the light emitted from the light-emitting element to exit from the light-emitting surface through the metal region.

12. The light emitting device according to claim 11 , wherein the light emitting element has an emission peak wavelength in the range of 320 nm to 495 nm.

13. preparing a light transmitting portion having an exit surface through which light is emitted; providing a metal film having a thickness of 1 nm to 10 nm on the light-emitting surface; and heating the metal film formed on the light-emitting surface to form a metal region containing metal that has been granulated by heating.

14. The method for manufacturing a light-transmitting member according to claim 13 , wherein the metal film is heated at a temperature of 900° C. or higher and 1100° C. or lower in the step of forming the metal region.

15. The method for manufacturing a light-transmitting member according to claim 13 or 14, wherein the metal is gold.

16. 16. The method for manufacturing a light-transmitting member according to claim 13, wherein in the step of providing the metal film, a protective film is further formed on the metal provided on the light-emitting surface, and then in the step of forming the metal region, the metal film is heated.

17. the protective film formed in the step of providing the metal film is a silicon film, The method for manufacturing a light-transmitting member according to claim 16 , wherein the step of forming the metal region causes the protective film to become a silicon oxide film obtained by oxidizing the silicon film through heating.

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