JP2008021973A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device with high power and long life. <P>SOLUTION: The light emitting device is made up of a light source for emitting excitation light and a wavelength converter for absorbing at least a part of the excitation light and emitting a different wavelength. The wavelength converter has a plurality of layers/areas arranged at least on a cross section intersecting the introduction direction of the excitation light, and at least two of the plurality of layers/areas are made of a material having a different tolerance to the excitation light. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention mainly relates to a light emitting device having a light source and a wavelength conversion member.

  Conventionally, there has been a demand for a light emitting device capable of accurately reproducing color information with high output. Today, it has been proposed to use a light emitting element such as a light emitting diode (hereinafter also referred to as “LED”) or a laser diode (hereinafter also referred to as “LD”) as the light source (for example, Patent Document 1).

  LEDs and LDs are small and power efficient, emit light in vivid colors, and do not have to worry about running out of balls. In particular, since the LD has a higher light density than the LED, a light-emitting device with higher brightness can be realized.

Special table 2003-515899 gazette

  However, for example, in the LED and LD described in Patent Document 1, when the light from the LED or LD is emitted to the outside via the wavelength conversion member, the wavelength conversion member deteriorates due to heat caused by the light, There has been a problem that light from the light emitting element cannot be sufficiently emitted to the outside, or in some cases, the wavelength conversion member is discolored and cannot be used as a light emitting device.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a light-emitting device with high output and long life.

  The light-emitting device of the present invention includes a light source that emits excitation light and a wavelength conversion member that absorbs at least a part of the excitation light and emits different wavelengths, and the wavelength conversion member includes at least the excitation light. A plurality of layers / regions are arranged in a cross section crossing the introduction direction, and at least two layers / regions of the plurality of layers / regions are formed of materials having different resistance to excitation light. And

In this light emitting device, it is suitable that the tolerance to the excitation light is expressed as the linearity of the output of the emitted light with respect to the output of the introduced excitation light.
Further, the wavelength conversion member is disposed so that the outer layer / region surrounds the inner layer / region in all directions orthogonal to the introduction direction of the excitation light, and the inner layer / region is the outer layer / region. It may be made of a material that is more resistant to excitation light than the region, and the wavelength converting member is arranged in all directions so that the outer layer / region surrounds the inner layer / region, and the outer The layer / region may be made of a material having higher resistance to excitation light than the inner layer / region.

Furthermore, you may provide the light guide member which guides excitation light to the wavelength conversion member from a light source.
It is preferable that the light guide member and the wavelength conversion member are optically coupled so that excitation light is incident on a layer / region inside the wavelength conversion member.
The wavelength conversion member is preferably configured to include a phosphor and a translucent material.
Furthermore, you may provide the coating | coated member which coat | covers at least one part of the side surface of a light guide member.
The light source is preferably a laser diode, and the light guide member is preferably an optical fiber.

  Moreover, the manufacturing method of the light-emitting device of this invention prepares 2 or more types of the mixture which mixed (1) at least 1 sort (s) selected from the group which consists of a fluorescent substance, a diffusing agent, and a filler in translucent material, predetermined | prescribed, The other mixture is sequentially coated so as to surround the mixture, and stretched at a temperature equal to or higher than the softening temperature of the translucent material to form a linear member having a desired diameter. Forming a wavelength conversion member by cutting at intersecting cut surfaces, or (2) a mixture in which at least one selected from the group consisting of a phosphor, a diffusing agent and a filler is mixed with a translucent material 2 or more types are prepared, a predetermined mixture is divided, polished and formed into a spherical shape, the surface of the obtained spherical product is coated with another mixture, and then the coated product is polished into a spherical shape By repeating the process to do more than once, it is almost spherical Characterized in that it comprises forming a wavelength conversion member.

  According to the light emitting device of the present invention, the wavelength conversion member and the light source can be accurately and easily arranged by laminating a plurality of layers / regions in a specific direction. Wavelength conversion weak against strong excitation due to heat from the light source and high-intensity light by placing a wavelength conversion member weak against strong excitation by the light source away from the light source or placing a wavelength conversion member strong against strong excitation close to the light source. Without directly exposing the member, deterioration of the wavelength conversion member can be prevented, and good quality light can be obtained over a long period of time without change.

  Further, according to the method for manufacturing a light emitting device of the present invention, the wavelength conversion member can be manufactured with very high accuracy, simply and efficiently.

  The light emitting device of the present invention includes at least a light source 10 and a wavelength conversion member 30, for example, mainly includes a light source 10, a light guide member 20, and a wavelength conversion member 30 as illustrated in FIG. 1. It may be.

The light source is a light source for emitting excitation light, and is not particularly limited as long as it emits light capable of exciting a phosphor described later. For example, a semiconductor light emitting element, a lamp, Examples include a device using an electron beam, plasma, EL or the like as an energy source. Especially, it is preferable that it is a light emitting element which discharge | releases the light which has a light emission peak in a 300-500 nm wavelength range, and LD and LED are used suitably. By using these, it is possible to provide a light emitting device that is excellent in initial driving characteristics, strong against vibration and repeated on / off lighting, small in size, and high in light output. In particular, since the LD has a higher light density than the LED, the luminance can be easily improved. On the other hand, since the LD has a high light density, the wavelength conversion member tends to generate heat, causing deterioration and discoloration. The present invention is particularly effective when an LD is used as the light source because the adverse effect on the wavelength conversion member due to heat can be greatly reduced.

For example, when an LD is used as a light source, as shown in FIG. 7A, a columnar stem column body 12 is placed on a disc-shaped stem bottom portion 11 and a side surface is connected to a sub light source. A light-emitting element having a light emission surface as an upper surface side, in which an LD is mounted as an optical semiconductor element 14 via a mount 13 via an adhesive member such as Au-Sn, may be used. The cap main body 15 that accommodates these LDs and the like is covered with the LDs and the like, and is welded in the vicinity of the periphery of the stem bottom 11 by resistance welding or the like. A through hole is formed in the center of the upper surface of the cap body 15 at a position corresponding to the light emitting portion of the LD. The outgoing optical axis of the semiconductor light emitting element 14 substantially overlaps the central axis of the upper surface of the cap body 15. In the through hole, a translucent material 17 or the like is fixed by an adhesive member such as silicone resin, ceramic, low melting point glass, or solder so that the light of the LD can be transmitted. It will be in the state.
A lead 16 for electrically connecting to the external electrode extends from the bottom surface of the stem bottom portion 11 in the vertical direction. Although not shown, the semiconductor light emitting element 14 is electrically connected to the lead 16 via a wire or the like. The shapes of the stem bottom 11, the stem column 12, the cap body 15, and the like are not limited as long as the semiconductor light emitting element 14 can be sealed. The stem bottom 11 is substantially cylindrical and the cap body 15 that closes the stem body 11 It is good also as a substantially disk shape.

Further, as shown in FIG. 8A, a side view type light emitting element having a light emitting surface in the side surface direction in which a through hole is formed in the side surface of the cap body 15 may be used.
Note that the stem constituting the light emitting element may be any one having good adhesion to the cap body and good heat dissipation, for example, copper, an alloy containing at least W or Mo in copper, iron, or a dissimilar material. The clad material etc. which were match | combined are mentioned. The stem bottom and the stem column are preferably a combination of materials having similar expansion coefficients. Thereby, both bondability can be improved.

The cap body is a material that can hermetically seal the internal space in which the semiconductor light emitting element is placed, and may be any material that has excellent adhesion to the stem or the like, or that has excellent thermal conductivity. Cu, Al, Ni, an alloy of Ni and Fe, Fe, iron-nickel-cobalt alloy (Kovar), stainless steel (SUS), and the like can be given.
For fixing stems and caps, for example, low melting point glass fixing, organic adhesive fixing (silicone, epoxy, etc.), inorganic adhesive fixing (ceramics: including Al ₂ O ₃ , ZrO ₂ , SiO ₂ etc.), Soldering (Au / Sn etc.) etc. are mentioned. Alternatively, a translucent material or the like may be directly dissolved in the cap body, or a transparent conductive film may be formed on one of the cap bodies, and then fixed by electrodeposition.

Wavelength conversion member The wavelength conversion member absorbs part or all of the excitation light emitted from the light source, and converts the wavelength to light in a predetermined wavelength range, for example, red, green, blue, and yellow that is an intermediate color thereof. , Blue-green, orange and the like can emit light having an emission spectrum.
Further, the wavelength conversion member has a plurality of layers / regions arranged in a cross section intersecting with the excitation light introduction direction. Therefore, the type of the wavelength conversion member is not limited as long as it is made of a material capable of realizing such a function. Here, the intersecting cross section means a cross section that intersects at less than ± 90 ° with respect to the introduction direction of the excitation light, but preferably a cross section orthogonal to the introduction direction of the excitation light and ± The range up to about 45 ° is appropriate. Also, the arrangement of a plurality of layers / regions means that the constituent materials are different for each layer (that is, the boundaries are clearly defined), and the constituent materials of the regions are gradually different ( That is, it includes both of those that are arranged (as if the boundary is not clear or there is a concentration distribution).

A plurality of layers / regions may be randomly, unevenly or evenly arranged in a cross section intersecting with the direction of excitation light introduction, but the outer layers / regions sequentially surround the inner layers / regions. It is preferable that they are arranged.
Furthermore, at least two layers / regions of the plurality of layers / regions are formed of materials having different resistance to excitation light. Here, the tolerance to the excitation light is expressed as the linearity of the output of the emitted light with respect to the output of the introduced excitation light. In general, at the same excitation wavelength, the output of the excitation light and the output of the emitted light have a linear relationship. However, in the present invention, the output of the excitation light is not affected by the magnitude of the output of the emitted light. Those that tend to deviate from the relationship can be judged to have low tolerance. The resistance to excitation light is different in at least two layers / regions of the plurality of layers / regions, but when there are three or more layers / regions, they may be different in all of them. It may be the same in the part. In addition, the resistance to the excitation light is such that the emission temperature of the wavelength conversion member that has been irradiated with the excitation light has a lower emission intensity than the one that has a large heat generation temperature, or linearity of the emission intensity, rather than a smaller one. In other words, there is a case where the resistance is small, but the light emission intensity of the emitted light is small or the linearity of the light emission intensity is low regardless of the heat generation temperature, and usually the resistance to the excitation light is small. Become.

  The material constituting the wavelength conversion member may be composed of layers / regions in which at least one layer / region of the plurality of layers / regions transmits and / or scatters light. These layers / regions are composed only of a phosphor, a translucent material containing a phosphor, a translucent material only, a diffusing agent for light diffusion, etc. And those containing a filler.

Examples of the phosphor include (i) alkaline earth metal halogen apatite, (ii) alkaline earth metal borate, (iii) alkaline earth metal aluminate, (iv) oxynitride or nitride, v) alkaline earth silicate, alkaline earth silicon nitride, (vi) sulfide, (vii) alkaline earth thiogallate, (viii) germanate, (ix) rare earth aluminate, (x) rare earth silicic acid Examples thereof include various compounds such as salts and organic and organic complexes mainly activated with lanthanoid elements such as (xi) Eu. These can be used alone or in combination of two or more. For example, a combination of (Sr, Ca) ₅ (PO ₄ ) ₃ Cl: Eu (blue light emission B), LAG or BaSi ₂ O ₂ N ₂ : Eu (green to yellow light emission), and SCESN (red light emission R) A combination of CCA, CCB, BAM (blue light emission B) and YAG (yellow light emission Y); CCA, CCB or BAM, etc. (blue light emission B), LAG (green light emission G), and SCESN (red light emission R); And the combination. Thereby, when combined with a light source having an emission peak wavelength in the range of 360 to 470 nm in the short wavelength region of visible light, white-color mixed light with good color rendering can be obtained. Further, LAG and (green emission G), SESN, SCESN or CaAlSiN _3: combination of Eu (red emitting R) and the like. Thereby, luminous efficiency can be further improved by combining with the light source which has a luminescence peak wavelength in 450 nm vicinity (for example, 400-460 nm).

  The translucent material is not particularly limited as long as it can transmit light from the light source, and organic materials such as epoxy resin and silicone resin, inorganic materials such as low-melting glass and crystallized glass, etc. Can be mentioned. Moreover, you may contain the filler mentioned later in these materials. Thereby, the light obtained from the light source can be used without wavelength conversion as it is, and the directivity of the light can be controlled.

In general, a translucent material of an organic material is easily deteriorated by light, but the configuration of the present invention is particularly effective when the translucent material is an organic member.
In order to obtain good color rendering properties, it is preferable to select a material such that the irradiation light after passing through the wavelength conversion member has an average color rendering index (Ra) of 70 or more, and further 80 or more.

  As described above, by using the wavelength conversion member, it is possible to synthesize light of a plurality of wavelengths and obtain white-color mixed light. However, the light of each color for adjusting the color tone does not necessarily have to be wavelength-converted by the wavelength conversion member, and the excitation light obtained from the light source may be used as it is. For example, a combination of light from a light source and light from one or more phosphors, or a combination of light from two or more phosphors.

As described above, the wavelength conversion member may contain a filler such as SiO ₂ . The filler is for reflecting and scattering irradiated light. Thereby, light can be scattered and taken out. In addition, color mixing can be improved and color unevenness can be reduced. Furthermore, since the viscosity can be adjusted by mixing a filler with the wavelength conversion member, it can be easily placed in any shape and in any part. The filler can be used by appropriately adjusting an arbitrary particle size, particle shape, and amount of use depending on the material constituting the wavelength conversion member.

  A plurality of layers / regions (for example, n types of layers / regions, where n is an integer of 2 or more, preferably about 2 to 5) are arranged from the center to the outer side in a cross section that intersects the introduction direction of the excitation light. As a mode in which the first layer / region is arranged so that the excitation light is first introduced into the layer / region containing the specific phosphor or not containing the phosphor, in a cross section orthogonal to the introduction direction The second layer / region to the n-th layer / region are arranged so that light emitted from the center to the outside is sequentially introduced into the second layer / region to the n-th layer / region. Here, the light introduced into the first layer / region may be emitted not only in the direction orthogonal to the introduction direction but also in the introduction direction. In addition, here, the “perpendicular cross section” is not limited to a cross section intersecting at 90 °, and a deviation of about ± 10 ° is allowed.

  For example, as shown in FIGS. 2 (a) and 2 (b), when the wavelength conversion member has a cylindrical shape, the first layer 40A having a cylindrical shape at the portion where the excitation light is first introduced, for example, the central portion. The cylindrical second layer 40B to n-th layer (40C when n is 3) are arranged concentrically on the outer periphery of the first layer 40A, and the section is Baumkuchen-shaped. An embodiment is mentioned. Accordingly, since excitation light is directly introduced, a layer that is resistant to strong excitation is disposed in a portion that is relatively easily deteriorated to reduce deterioration of the first layer, and as a result, the lifetime of the light emitting device. Can be improved.

  Further, as shown in FIGS. 3A and 3B, when the wavelength conversion member is spherical, the first layer 40A is formed at the center of the sphere, and the second layer 40B˜ An embodiment in which the nth layer (40C when n is 3) is arranged is exemplified. In particular, when the wavelength conversion member is spherical, it is introduced into the inner wavelength conversion member (phosphor) by disposing a layer resistant to strong excitation light or a layer not containing phosphor on the outer layer of the sphere. Since the light density of the excitation light to be reduced decreases, the deterioration of the wavelength conversion member can be reduced. In addition, a phosphor that is not excited at the wavelength of the excitation light is disposed on the outer layer of the sphere, and a phosphor that emits light at a wavelength that can receive the excitation light and excite the phosphor on the outer layer is disposed on the inner layer. The light density of the excitation light introduced into the light can be lowered, and deterioration of the wavelength conversion member can be effectively prevented.

  Furthermore, as shown in FIGS. 4A and 4B, when the wavelength conversion member is in a dome shape, the first layer 40A is provided at the portion where excitation light is first introduced, for example, the central portion, and the outer periphery thereof. The second layer 40B to the n-th layer (40C when n is 3) are arranged so as to surround a substantially similar dome shape. As a result, the excitation light is directly introduced into the layer resistant to strong excitation, and all the light emitted therefrom can be introduced into the second to n-th layers, thereby further improving the luminous efficiency. it can. In the case of a dome shape, since the distance from the excitation light introducing portion to the outer periphery is the same, the amount of the phosphor existing on the optical path through which the excitation light passes is the same, and color unevenness is further reduced. be able to.

  As described above, the shape of the wavelength conversion member can be a columnar shape, a dome shape, a spherical shape, a polygonal column, or a shape approximating these shapes. The size is not particularly limited and can be appropriately adjusted depending on the size of the light source to be used, the structure and size of a light guide member to be described later, and the like. For example, the diameter (or width) of the wavelength conversion member is preferably at least equal to or greater than the diameter of the light guide member. In particular, it is preferable that the diameter of the layer / region where the excitation light is first introduced or the innermost layer / region is equal to or larger than the diameter of the core of the light guide member. From another viewpoint, in the case of a spherical wavelength conversion member, the diameter of the central layer / region is preferably equal to or larger than the diameter of the core of the light guide member. The inner layer / region and the outer layer / region do not necessarily have the same shape (similarity), the inner layer / region is a cylinder, the outer layer / region is a combination of polygonal columns, and the inner layer The combination may be an oval / region, an outer layer / region having a spherical shape, an inner layer / region having a spherical shape, and an outer layer / region having a dome shape. The film thickness of the wavelength conversion member is not particularly limited, and can be appropriately adjusted depending on the material used, the amount of phosphor, and the like. For example, when the wavelength conversion member is formed with a thick film, the conversion efficiency is improved, and as a result, the light emission efficiency can be increased. On the other hand, the light emission efficiency may be impaired due to light absorption or the like. It is preferable to select an appropriate film thickness in consideration of these. In addition, the film thickness of each layer may differ.

  From such a point of view, it is preferable that the wavelength conversion member is formed of a material having a higher resistance to the excitation light than the other parts where the excitation light is first introduced. That is, for example, in FIGS. 2A and 2B and FIGS. 4A and 4B, the innermost first layer 40A is more than the outer second layer 40B. ), The outermost second layer B is preferably made of a material having higher resistance to excitation light than the inner first layer 40A. In other words, it is made of a heat-resistant translucent material, the phosphor content is small, the phosphor is not excited by the wavelength of the excitation light, or is resistant to the excitation light For example, it may be formed of a phosphor.

  From another point of view, the layer / region closer to the light source may not contain the phosphor, but only the translucent material may be arranged, and the layer / region on the far side may contain the phosphor or the like. Thereby, since the light density can be reduced at the end of the wavelength conversion member, the deterioration of the far layer / area can be reduced, and the light emission efficiency and the light output can be improved.

  Furthermore, the layer / region near the light source may contain a phosphor and / or filler that is not excited by the excitation light and easily reflects the excitation light, and the phosphor / etc. May be contained in the layer / region on the far side. Good. Thereby, the excitation light can be scattered on the incident side of the wavelength conversion member and reflected on the emission side, and all of the wavelength-converted excitation light can be efficiently extracted. Furthermore, since the light density of the excitation light can be further reduced in the near layer / region, deterioration of the near layer / region can be reduced.

  Further, a layer / region closer to the light source may contain a phosphor highly resistant to heat and light, and a layer / region farther away may contain a phosphor regardless of heat or light resistance. That is, the layer / region having the first phosphor and the layer / region having the second phosphor may be sequentially arranged from the side close to the light source. Here, the first phosphor preferably has a lower heat generated by excitation light or a higher resistance than the second phosphor. Thereby, deterioration as the whole wavelength conversion member can be reduced. The heat generated in the first phosphor and the second phosphor, for example, irradiates the first phosphor and the second phosphor of the same volume with excitation light, and compares the heat generation temperatures of the phosphors. Can be measured. The tolerance can be measured by comparing the emission intensity of each emitted light with respect to the output of the excitation light.

  The wavelength conversion member is, for example, the above-described phosphor or the like, optionally mixed with a light-transmitting material together with a filler, and if necessary, using a suitable solvent, potting method, spray method, screen printing method, stencil printing In addition, casting method, compression method, transfer method, injection method, extrusion method, lamination method, calendar method, injection mold method, etc. plus chip molding method, vacuum coating method, powder spray coating method, electrostatic The desired shape can be formed by using a deposition method, an electrophoretic deposition method, or the like. Further, without using a light-transmitting material, for example, a method of mixing with a phosphor or the like, optionally with a filler and a suitable solvent, and optionally molding while heating, electrodeposition, etc. may be used. Good.

  In particular, in the case of a disk shape as shown in FIGS. 2A and 2B, a phosphor and / or a filler is optionally contained in the light-transmitting material according to the number of n layers stacked. The innermost one is formed into a rod shape, and the other ones are sequentially coated so as to surround it, and then stretched (heated) at a predetermined temperature to obtain a wire having a desired diameter. A cylindrical member can be obtained by forming a cylindrical member and cutting the linear member. The stretching temperature is preferably equal to or higher than the softening temperature of the translucent material, and can be appropriately determined depending on the translucent material used. The diameter of the linear member can be appropriately determined according to the core diameter of the light guide member.

  In addition, in the case of a spherical shape as shown in FIGS. 3 (a) and 3 (b), a light-transmitting material arbitrarily containing phosphors and / or fillers is prepared and divided into appropriate sizes. Then, for example, it is molded into a spherical shape by using polishing or a method according thereto, and then the obtained spherical product optionally contains a phosphor and / or a filler in another translucent material. A spherical member can be obtained by covering the coated material and similarly repeating the step of forming into a spherical shape using polishing or the like once or more. The polishing method can be appropriately selected depending on the material to be used, the amount to be processed, the size of the spherical object to be obtained, etc. For example, barrel polishing is suitable.

  As shown in FIG. 1, when the light guide member for deriving excitation light is provided, the wavelength conversion member may be attached to the tip of the wavelength conversion member, or the connection portion between the light source and the light guide member It may be attached to the light source itself without using the light guide member. When attaching to the connection part of a light source and a light guide member, it can be used also in the location where the front-end | tip of a light guide member gets dirty. In addition, the wavelength conversion member can be easily replaced. Furthermore, productivity can be improved by providing the wavelength conversion member at various positions. In these cases, it is suitable to optically connect the light guide member and the wavelength conversion member so that the excitation light is incident on the inner layer of the wavelength conversion member. Here, optically connected means that the state where light is transmitted is maintained, and a light-transmitting member or the like may be interposed therebetween.

  The wavelength conversion member may be formed so as to cover only the end portion (end surface) of the light guide member, but if the light emitting device includes a cover member described later, the wavelength conversion member may be formed only at the end portion of the light guide member. Instead, it is preferable that the end face of the covering member is covered over a part of the end face and further the entire end face. Thereby, a wavelength conversion member will be formed in a wide area | region, while improving heat dissipation, adhesiveness will improve and peeling of a wavelength conversion member etc. can be prevented. Moreover, the density of the light irradiated to a wavelength conversion member can be reduced, and it becomes possible to prevent deterioration of a wavelength conversion member. Furthermore, the light extraction efficiency is improved, and a light-emitting device with high luminance can be obtained. This effect improves as the covering area of the end of the covering member with the wavelength conversion member increases.

  In addition, when the wavelength conversion member is attached to the light source itself, for example, as shown in FIG. 7B, an adhesive member such as silicone resin, ceramic, low-melting glass, solder, or the like is placed in the through hole of the cap body 15. The wavelength conversion member 40 may be fixedly provided. Further, the wavelength conversion member 40 may be directly melted on the cap body 15. Thereby, the wavelength of the light from the semiconductor light emitting element 14 can be converted, and the heat from the wavelength conversion member 40 generated along with the conversion can be released to the outside through the cap body 15. Therefore, deterioration of the wavelength conversion member 40 can be suppressed.

  Further, as shown in FIG. 7C, the translucent material 17 may be fixed in the through hole of the cap body 15, and the wavelength conversion member 40 may be provided on the upper surface thereof. Thereby, the material with higher adhesiveness with the cap main body 15 than the wavelength conversion member 40 can be used as the translucent material 17, and the airtightness inside a cap can further be maintained. In addition, since the light from the semiconductor light emitting element 14 is irradiated to the wavelength conversion member 40 through the translucent material 17, deterioration of the wavelength conversion member 40 can be suppressed.

  As shown in FIGS. 7D and 7E, the cap body 15 to which the translucent material 17 is fixed is further covered with the second cap body 18 having the wavelength conversion member 40 on the upper surface. Also good. At this time, the translucent material 17 and the wavelength conversion member 40 fixed to the cap bodies 15 and 18 are provided at positions where light emitted from the semiconductor light emitting element is irradiated. Thereby, it can be set as the structure which included the semiconductor light emitting element twice, and can further improve airtightness. Moreover, since the light from the semiconductor light emitting element is irradiated to the wavelength conversion member 40 through the translucent material 17, the deterioration of the wavelength conversion member 40 can be suppressed. Particularly in the latter case, since the cap bodies 15 and 18 are exposed to the outside, the heat dissipation effect can be enhanced. This structure can be realized, for example, by connecting the stem bottom 11 and the cap body 15 by resistance welding and connecting the cap body 15 and the second cap body 18 by YAG laser welding. .

  Further, as shown in FIG. 8B, a wavelength conversion member 40 may be provided in place of the translucent member 17, and as shown in FIG. 11 may be provided. In this case, the reflection member 19 reflects the light of the semiconductor light emitting element 14 emitted in the side surface direction of the cap body 15, and the reflected light is irradiated to the wavelength conversion member 40 provided on the upper surface of the cap body. It is injected outside. On the surface of the reflecting member 19, a reflecting film (such as a material having high reflectance such as Ag, Al, Au, Pt, Rh, Pd, In, Ni, or an alloy thereof) can be provided. Further, as shown in FIG. 8D, the reflection member 19 may be provided on the stem bottom 11, and the wavelength conversion member 40 may be disposed between the reflection member 19 and the semiconductor light emitting element 14.

The light guide member is a translucent member for guiding light from the light source to the wavelength conversion member. The light guide member preferably extends in the longitudinal direction and is configured to be bendable. By providing this light guide member, light can be easily led to a desired position. In addition, although the cross section of a light guide member is preferable circular, it is not limited to this. Although the diameter of the light guide member 20 is not specifically limited, For example, the thing of 3000 micrometers or less, 1000 micrometers or less, 400 micrometers or less, and also 200 micrometers or less can be used. Specific examples include core / cladding = 114/125 (μm), 72/80 (μm), and the like. The diameter of the light guide member 20 is the average length in the cross section when the cross section is not circular.

  One end of the light guide member is disposed on the light source side, and the other end is disposed on the wavelength conversion member side described later. Any light guide member may be used as long as it guides light from the light emitting element to the wavelength conversion member. For example, an optical fiber can be used. Thereby, the light from a light source can be derived | led-out efficiently. An optical fiber is usually configured such that a core having a high refractive index is disposed on the inside and a cladding having a low refractive index is disposed on the outside. The shape of the end of the light guide member on the light source side and / or the end of the wavelength conversion member side is not particularly limited, and includes various shapes such as a flat surface, a convex lens, a concave lens, and a partially uneven shape. can do. For example, when an optical fiber is used as the light guide member, the core and / or the clad can be formed in these shapes at each end.

The light guide member may be either a single wire fiber or a multi-wire fiber. Moreover, either a single mode fiber or a multimode fiber may be used, but a multimode fiber is preferable.
The material of the light guide member is not particularly limited, and examples thereof include quartz glass and plastic. Among these, the core material is preferably composed of pure silica (pure quartz). Thereby, transmission loss can be suppressed.
In addition, you may make the fluorescent substance mentioned above contain in a part in a light guide member, for example, a core material.

Covering member In the light emitting device of the present invention, it is preferable that the tip of the light guide member, that is, the end not connected to the light source, is supported by the covering member. With such a covering member, it becomes easy to fix light emitted from the light guide member. Further, the light emission efficiency can be improved according to the material and shape, and the assembly as a light emitting device is facilitated. Therefore, the covering member may be made of any material and shape as long as it can support the light guide member.

The covering member is a material that reflects the excitation light and / or wavelength-converted light, that is, a material that has high reflectivity for these lights, high thermal conductivity, or a material that has two or more of these properties. It is preferable that it is formed. For example, a material having a reflectance of 80% or more and a thermal conductivity of 0.1 W / m · ° C. or more with respect to excitation light and / or wavelength-converted light is preferable. Specific examples include Ag, Al, Al ₂ O ₃ , ZrO ₂ , SiC, SiO ₂ , stainless steel (SUS), carbon, copper, and barium sulfate. Of these, Ag is preferable because of its high reflectance.

  Further, in order to increase the reflectivity, a mirror may be attached to the end face of the covering member to perform specular reflection, or irregular reflection may be performed, or irregularities may be processed. Thus, once the excitation light or wavelength-converted light emitted from the light guide member returns to the light guide member side by reflection, the excitation light and the wavelength are converted by reflecting again by the covering member. Light can be effectively extracted outside, and the output can be improved. Moreover, when the unevenness | corrugation is formed, while the adhesiveness to the coating | coated member of a wavelength conversion member improves, while being able to increase the heat dissipation of a wavelength conversion member, peeling and deterioration of a wavelength conversion member can be prevented. . In addition, it is preferable that the surface having specular reflection and / or unevenness is formed not only on the covering member but also on the end surface of the light guide member.

  For example, the covering member may have a cylindrical shape that surrounds the outer periphery of the light guide member, or various functional films / members may be integrated with each other in order to provide various functions to the end surface of the light guide member. It may be attached separately, or a cover or cap for covering the end face of the light guide member, various functional films / members or the like may be attached integrally or separately.

A lens may be provided on the emission side of the other member light sources.
The lens may have any shape as long as the light emitted from the light source is collected on the light guide member, and a plurality of lenses may be arranged side by side between the light source and the light guide member. The lens can be formed of inorganic glass, resin, or the like, and among them, inorganic glass is preferable. A lens is provided between the light source and the light guide member, and excitation light emitted from the light source via the lens can be introduced into the light guide member, so that the light output of the excitation light emitted from the light source is maintained. The light can be efficiently guided into the light guide member.

  Further, the lens provided in the light source may contain a phosphor or the like. Thereby, the lens itself can function as a wavelength conversion member. Since the excitation light that has been wavelength-converted by the lens function is surely collected on the emission part, color variation can be eliminated, and the wavelength conversion member can also be manufactured by manufacturing the lens. The manufacturing cost of the conversion member can be suppressed.

  It is preferable to attach various functional films / members at appropriate positions in the light-emitting device of the present invention, not limited to the case of attaching to the covering member described above. Examples of the functional film / member here include a wavelength conversion light reflection film, an excitation light reflection film, a diffusion prevention member, a diffusion member, and a blocking member.

  The wavelength-converted light reflecting film prevents the light converted in wavelength by the wavelength conversion member from returning to the excitation light incident side, and extracts the light returned to the excitation light incident side as light by reflecting it outside. Can be used. Therefore, the wavelength conversion reflection film is preferably formed of a material that allows only light having a specific wavelength to pass therethrough and reflects the specific wavelength, that is, the wavelength-converted light. Thereby, the light which returned to the excitation light incident side can be reflected, and the luminous efficiency can be improved.

  The excitation light reflecting film can be used for preventing excitation light from being directly irradiated to the outside, leakage of excitation light from an unintended portion, and the like. Thereby, for example, the luminous efficiency can be improved by returning the excitation light that has passed through the wavelength conversion member but was not wavelength-converted by a phosphor or the like into the wavelength conversion member again. Therefore, the excitation light reflecting film is preferably formed of a material that allows only the wavelength-converted light having a specific wavelength to pass therethrough and reflects the excitation light.

  The diffusion preventing member can be used to prevent the excitation light and / or the wavelength-converted light from diffusing in an unintended direction. Therefore, it is preferable that the diffusion preventing member is made of a material and a shape that block excitation light or wavelength-converted light by 90% or more. For example, the light guide member and the wavelength conversion member may be disposed so as to be sandwiched between the light guide member and the wavelength conversion member at a joint, or a boundary portion between the light guide member and the wavelength conversion member. May be disposed so as to surround the outer surface, or may be disposed so as to cover the outer surface of the wavelength conversion member other than the wavelength-converted light irradiation portion.

  The diffusing member can be used to improve the luminous efficiency by diffusing mainly the excitation light, in particular, irradiating more excitation light to the phosphor or the like of the wavelength conversion member. Accordingly, the diffusing member is preferably disposed between the light exit of the light guide member and the wavelength conversion member. As the diffusion member, for example, among the above-described resins, it is preferable to use a resin having a relatively high refractive index, a resin containing the above-described filler in the above-described resin, or the like. Especially, what contains a filler in a silicone resin is preferable. Thereby, since the density of the light irradiated to a wavelength conversion member can be reduced and the burden of the wavelength conversion member per unit area can be reduced, deterioration and discoloration of the coating member which comprises a wavelength conversion member can be reduced. Therefore, the light emission efficiency, linearity, and the maximum value of light emission output can be improved.

  The blocking member preferably blocks 90% or more of light from the light source. Thereby, only light of a predetermined wavelength can be extracted. For example, in the case of using a light emitting element that emits ultraviolet rays harmful to the human body, in order to block the ultraviolet rays, an ultraviolet absorber or a reflective agent or the like may be used as a blocking member and included in the wavelength conversion member in the light outlet portion. it can. Especially, it is preferable to use a reflective agent from a viewpoint which can improve luminous efficiency more. Since the blocking member also has a function as the above-described excitation light reflecting film, diffusion preventing film, and the like, it does not have to be strictly distinguished from these.

Embodiment of Light Emitting Device As shown in FIG. 1, the light emitting device of the present invention may be composed of one light source, one light guide member, and one wavelength conversion member, or one light source. And a single wavelength conversion member built in the light source and a single light guide member, or a light emitting device on which a plurality of such light emitting devices of one unit are mounted.
Moreover, you may comprise so that one light source may be equipped with the several light guide member and the wavelength conversion member corresponding to it. Moreover, you may have the structure which wavelength-converts the light from several light guide members in one light source, and the light from these light guide members with one wavelength conversion member. Furthermore, you may have the structure which wavelength-converts the light from these light guide members, the light guide member corresponding to it, and the light from these light guide members with one wavelength conversion member. You may have the structure which wavelength-converts the light from the some light source, one light guide member, and the light from the light guide member with one wavelength conversion member. Further, these light emitting devices may be combined and used as one light emitting device.

Application of light-emitting device The light-emitting device of the present invention includes, for example, ordinary lighting fixtures, vehicle-mounted lighting (specifically, light sources for headlights, tail lamps, etc.), endoscope devices, fiberscopes, current leakage It can be used as a light-emitting device used in a place where a light source, a point light source, or a place where it is difficult to replace the light source.

  Therefore, this light emitting device uses an imaging member (that is, an electronic component (light receiving element) that converts an optical image into an electrical signal), specifically, a charge-coupled device (CCD), a CMOS image sensor (CMOS), or the like. Used with image sensors, image signal processing devices that convert electrical signals into image signals, indicators that display electrical signals or measured values, displays that output image signals and display images, computers that perform various processes and calculations, etc. can do. In particular, when an imaging element is used as the imaging member, the optical image of the subject can be handled easily.

  For example, the light receiving element (for example, a photodiode) may be provided separately from the light emitting device, but may be provided near the light emitting element in the light source, around the light guide, or in the light guide tip member. Good. Thereby, the light quantity emitted from the light emitting element by the light receiving element can be observed, and when the light quantity is less than the constant light quantity, the constant light quantity can be maintained by adjusting the current supplied to the light emitting element.

  The light-emitting device of the present invention has little color tone variation, very rich color reproducibility, and very high color rendering, so it is extremely suitable for use with devices that require clear imaging, such as endoscopic devices. Exhibits excellent effects.

  Furthermore, the light emitting device of the present invention can also be used for visible light communication. That is, it is possible to construct a wireless environment by using visible light obtained by the light emitting device described above and adding a communication function to the light emitting device, for example. Thereby, since a laser element is used as the light source, a modulation speed of several hundred MHz can be realized.

Hereinafter, specific examples of the light-emitting device of the present invention will be described in detail with reference to the drawings.
Example 1
As shown in FIG. 1, the light emitting device includes a light source 10, a light guide member 20, a covering member 30, and a wavelength conversion member 40.
As the light source 10, a laser diode, which is the light emitting element 10 made of a GaN-based semiconductor having an emission peak wavelength near 445 nm, was used. A lens 2 for condensing the excitation light 1 from the laser diode is disposed in front of the laser diode.

  One end of the light guide member 20 is connected to the light emitting portion of the light source 10, and the other end is connected to a covering member 30 made of alumina and having a diameter of 0.7 mm. For example, SI type 114 (μm: core diameter) / 125 (μm: clad diameter) made of quartz was used as the light guide member.

  As shown in Table 1, the wavelength conversion member 40 is mixed in a silicone resin so that various phosphors are uniformly dispersed, and the second layer is formed on the outer periphery of the first layer 40A which is an inner layer. It was molded into a disk shape of a double structure in which 40B is disposed, and attached to the tip of the light guide member 20 as shown in FIG.

In Table 1, the phosphors are Lu ₃ Al ₅ O ₁₂ : Ce (LAG: G) that emits green light, Ca _0.99 AlSiB _0.10 N _3.1 : Eu _0.01 (CASBN: R) that emits red light, and blue. Ca ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu (CCA: B) that emits light and YAG (Y) that emits yellow light were used. These phosphors are kneaded in the silicone resin until uniform. At this time, the ratio between the phosphor and the resin was appropriately adjusted at a weight ratio of about 2 to 40:98 to 60.

The wavelength conversion member 40 was mixed with a diffusing agent (for example, SiO ₂ filler) for diffusing light emitted from the laser diode. In this case, the film thickness of the wavelength conversion member 40 is, for example, about 500 μm.

In particular, in No. 2 in Table 1, the ratio of Lu ₃ Al ₅ O ₁₂ : Ce (LAG: G) to the resin is 33:67 by weight ratio, Ca _0.99 AlSiB _0.10 N _3.1 : Eu _0.01 (CASBN: When light was emitted using a wavelength conversion member in which the ratio of R) to the resin was 4:96 by weight, light output characteristics as shown by the solid line in FIG. 6 were exhibited. Further, as a comparative example, a wavelength conversion member having a single-layer structure and using LAG: CASBN: resin (32: 1: 67) was produced, and light was emitted in the same manner. The characteristics are shown. That is, it was confirmed that the linearity was improved and the maximum luminous flux was increased by using the structure of multiple layers / regions. In any of these, the same phosphor was used, and thus the spectral distribution was almost the same.

  In this light emitting device, the excitation light 1 emitted from the laser diode passes through the lens 2 and is condensed on the emission portion, and the condensed excitation light 1 passes through the light guide member 20 and is fluorescence of the wavelength conversion member 40. By irradiating the body and converting the wavelength, the average color rendering index (Ra) was 80 or more, and a good white color mixture was emitted.

  In the obtained light-emitting device, the first phosphor highly resistant to excitation light is disposed on the side closer to the light source (inner first layer, A layer), and the side farther from the light source (outer second layer, B). It is possible to effectively reduce the deterioration of the wavelength conversion member due to heat or the like by disposing the second phosphors having low resistance to excitation light in the layer). In addition, since light is scattered by the first phosphor included in the first layer and the light density is lowered, heat generation of the second phosphor in the second layer can be further reduced.

Alternatively, a translucent material that transmits excitation light is disposed on the side closer to the light source (inner first layer, A layer) or the first phosphor that is not excited at the wavelength of the light source, and the side far from the light source ( By disposing the second phosphors for wavelength conversion by excitation light in the outer second layer (B layer), the deterioration of the wavelength conversion member due to heat or the like can be effectively reduced. In particular, since the light contained in the first layer is scattered and the light density is lowered, the heat generation of the second phosphor in the second layer can be further reduced.
As a result, a reliable light-emitting device with high light-emission output can be obtained.

Example 2
In this light emitting device, as shown in Table 2, the wavelength conversion member 40 is mixed in a translucent material so that various phosphors are uniformly dispersed, and the first layer 40A, which is an inner layer, is mixed. Formed in the shape of a triple-layered disc having the second layer 40B on the outer periphery and the third layer 40C on the outer side, and attached to the tip of the light guide member 20 as shown in FIG. Except for this, the configuration is the same as that of the first embodiment.

  The obtained light emitting device can greatly reduce the deterioration of the wavelength conversion member 40 due to heat or the like, as in the first embodiment. As a result, a reliable light-emitting device with high light-emission output can be obtained.

Example 3
In this light emitting device, as shown in Table 3, the wavelength conversion member 40 is mixed in a translucent material so that various phosphors are uniformly dispersed, and the wavelength conversion member 40 is placed on the outer periphery of the inner first layer 40A. 2 except that the second layer 40B is molded into a double spherical shape and attached to the tip of the light guide member 20 as shown in FIG. 5C.

The obtained light emitting device can greatly reduce the deterioration of the wavelength conversion member 40 due to heat or the like, as in the first embodiment. As a result, a reliable light-emitting device with high light-emission output can be obtained.
In particular, since the wavelength conversion member is formed into a spherical shape, the contact area at the interface between the wavelength conversion member and the light guide member, which is generally most susceptible to deterioration, is minimized while efficiently converting the wavelength of the excitation light introduced inside. Because the portion of the wavelength conversion member closest to the light guide member can be made of a material with low heat generated by excitation light or a material with high resistance, deterioration due to heat of the wavelength conversion member is further reduced. Can be made.

Example 4
In this light emitting device, as shown in Table 4, the wavelength conversion member 40 is mixed in the translucent material so that various phosphors are uniformly dispersed, and the wavelength conversion member 40 is placed on the outer periphery of the inner first layer 40A. Example 2 except that the second layer 40B and the third layer 40C on the outer side thereof are molded into a triple spherical shape and attached to the tip of the light guide member 20 as shown in FIG. 1 has the same configuration.

  The obtained light emitting device can significantly reduce the deterioration of the wavelength conversion member 40 due to heat or the like, similar to the third embodiment. As a result, a reliable light-emitting device with high light-emission output can be obtained.

  The light-emitting device of the present invention can be used for lighting fixtures, on-vehicle lighting, displays, indicators, and the like. It can also be used for endoscope devices that image the inside of living bodies, fiberscopes that can illuminate narrow gaps and dark spaces, and various industrial devices that require illumination without current leakage or heat generation. it can.

It is a schematic block diagram which shows embodiment of the light-emitting device of this invention. It is a schematic block diagram for demonstrating the structure of the wavelength conversion member in the light-emitting device of this invention. It is a schematic block diagram for demonstrating another structure of the wavelength conversion member in the light-emitting device of this invention. It is a schematic block diagram for demonstrating another structure of the wavelength conversion member in the light-emitting device of this invention. It is a schematic block diagram which shows the structure of the front-end | tip part in the light-emitting device of this invention. 6 is a graph showing an emission spectrum of the light emitting device of Example 1. FIG. It is a schematic block diagram for demonstrating the structure of another light source and / or wavelength conversion member in the light-emitting device of this invention. It is a schematic block diagram for demonstrating the structure of another light source and / or wavelength conversion member in the light-emitting device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Excitation light 2 Light 10 Light source 11 Stem bottom part 12 Stem pillar 13 Submount 14 Semiconductor light emitting element 15 Cap main body 16 Lead 17 Translucent material 18 Second cap main body 19 Reflective member 20 Light guide member 30 Cover member 40 Wavelength conversion Member 40A first layer 40B second layer 40C third layer

Claims (12)

A light source that emits excitation light, and a wavelength conversion member that absorbs at least part of the excitation light and emits different wavelengths,
The wavelength conversion member has a plurality of layers / regions arranged at least in a cross section intersecting the introduction direction of the excitation light,
At least two layers / regions among the plurality of layers / regions are formed of materials having different resistances to excitation light.   The light-emitting device according to claim 1, wherein the resistance to the excitation light is expressed as linearity of the output of the emitted light with respect to the output of the introduced excitation light.   The wavelength conversion member is disposed so that the outer layer / region surrounds the inner layer / region in all directions orthogonal to the direction of introduction of the excitation light, and the inner layer / region is more than the outer layer / region. The light emitting device according to claim 1, wherein the light emitting device is made of a material having high resistance to excitation light.   The wavelength converting member is arranged so that the outer layer / region surrounds the inner layer / region in all directions, and the outer layer / region is more resistant to excitation light than the inner layer / region. The light emitting device according to claim 1 or 2, wherein the light emitting device is made of a material.   Furthermore, the light-emitting device as described in any one of Claims 1-4 provided with the light guide member which guides excitation light to a wavelength conversion member from a light source.   The light-emitting device according to claim 5, wherein the light guide member and the wavelength conversion member are optically coupled such that excitation light is incident on a layer / region inside the wavelength conversion member.   The light-emitting device according to claim 1, wherein the wavelength conversion member includes a phosphor and a translucent material.   Furthermore, the light-emitting device as described in any one of Claims 1-7 provided with the coating | coated member which coat | covers at least one part of the side surface of a light guide member.   The light emitting device according to any one of claims 1 to 8, wherein the light source emits light having an emission peak in a wavelength range of 300 nm to 500 nm.   The light emitting device according to any one of claims 1 to 9, wherein the light source is a laser diode, and the light guide member is an optical fiber. Two or more mixtures prepared by mixing at least one selected from the group consisting of a phosphor, a diffusing agent, and a filler into a translucent material,
Coating other mixtures in order to surround a given mixture,
At a temperature equal to or higher than the softening temperature of the translucent material, a linear member having a desired diameter is formed by stretching,
The method for manufacturing a light-emitting device according to claim 1, comprising forming a wavelength conversion member by cutting the linear member at a cut surface that intersects the extending direction. Two or more mixtures prepared by mixing at least one selected from the group consisting of a phosphor, a diffusing agent, and a filler into a translucent material,
Divide a given mixture, polish and shape it into a sphere,
Forming a substantially spherical wavelength conversion member by coating the surface of the obtained spherical product with another mixture and then polishing the coated product to form a spherical shape one or more times. The manufacturing method of the light-emitting device as described in any one of Claims 1-10.