JP2007180339A - Light emitting device and its process for fabrication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device which can irradiate uniform light in an irradiation surface. <P>SOLUTION: The light emitting device contains a base mount having a recess with a bottom and side faces, a light emitting element laid in the bottom of the recess of the base mount, a first member covering the light emitting element and arranged in the recess of the base mount, and a second member which covers the first member, is arranged in the recess of the base mount and the light from the light emitting element, contains an optical diffusion member which diffuses the light from the emitting element, and contains many optical diffusion members in this volume rather than the near side of the base mount in the upper part of the light emitting element adjacent to the light emitting element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting device, and particularly to a light emitting device having a light emitting element.

A light-emitting device using a light-emitting element emits light with a small color, high power efficiency, and vivid colors. In addition, since the light-emitting element is a semiconductor element, there is no fear of a broken ball. Further, it has excellent initial driving characteristics and is strong against vibration and repeated on / off lighting. Because of such excellent characteristics, light-emitting devices using light-emitting elements such as light-emitting diodes (LEDs) and laser diodes (LDs) are used as various light sources.
Some conventional semiconductor light emitting devices have the following configuration. FIG. 12 is a schematic cross-sectional view showing a conventional light emitting device. FIG. 13 is a schematic view showing an image of an irradiation surface when a conventional light emitting device emits light. A conventional light emitting device includes a light emitting element 201, a lead 202 on which the light emitting element 201 is placed, a coating resin 203 provided on the light emitting element 201, and a mold member 206 that protects the coating resin 203. As the light emitting element 201, a light emitting element capable of emitting blue light having a light emitting layer made of a gallium nitride compound semiconductor is used. The light emitting element 201 is disposed on the bottom surface in the recess of the lead 202. The upper part of the light emitting element 3 and the periphery thereof are covered with a coating resin 203 made of a transparent epoxy resin containing particles of yttrium / aluminum oxide (hereinafter referred to as YAG) phosphor 207 activated by cerium, for example. . The coating resin 203 includes a yellow photoluminescence phosphor 207 that absorbs at least part of blue light from the light emitting element 201 and converts the wavelength to emit fluorescence. In the light emitting device, white light is obtained by mixing blue light from the light emitting element 201 and yellow light of the phosphor 207.
However, the light emitted from the light emitting device has a donut-shaped yellow ring on the light irradiation surface. That is, blue light is strongly emitted from the upper surface of the light emitting element 201, and white light 211 having a slightly blue tint is formed in the center of the donut shape. On the other hand, the light emitted from the side surface of the light emitting element 201 is strongly irradiated on the phosphor 207 and is also irradiated on the side surface of the concave portion, and white light 212 having a slightly yellowish shape is formed in a donut shape. This is considered to be due to the concave portion of the lead 202 that reflects the light from the light emitting element 201.

  Moreover, there exists a light-emitting device containing the diffusion material which makes a mold member milky white (for example, refer patent document 1). However, in this light emitting device, since the diffusing material is uniformly contained in the entire mold member, the function of the mold member originally provided for condensing light becomes insufficient.

Furthermore, a light emitting device is known in which a fluorescent material 227 is disposed on the upper part of the diffusion resin 224 (see, for example, Patent Document 2). FIG. 14 is a schematic cross-sectional view showing a conventional light emitting device.
In this light emitting device, a light emitting element 221 is disposed in a recess of one lead frame 222, and the other lead frame and the light emitting element 221 are connected by a bonding wire. The periphery of the portion below the light emitting layer in the concave portion of the light emitting element 221 is sealed with a transparent resin or a diffusion resin 224, and the fluorescent material 227 is applied only on the upper surface of the light emitting layer. A diffusion member 225 is included in the diffusion resin 224. The fluorescent material 227 is contained in the resin 223. The resin 223 is covered with a mold member 226. Accordingly, it is described that the distance that the light from the light emitting element 221 passes through the fluorescent material 227 is substantially the same regardless of the route, and the color mixing property is improved.
However, since a recess is formed in the lead frame 222 in which the light emitting element 221 is arranged, it is difficult to make light transmission paths from the light emitting element 201 substantially the same. That is, the light emitted from the light emitting element 221 is irradiated onto the side surface of the concave portion to form a donut-shaped yellow ring on the irradiated surface. On the other hand, light emitted from the upper surface of the light emitting element 221 forms a donut-shaped central portion on the irradiation surface. Therefore, it has not yet reached the suppression of the occurrence of yellow rings. Even if the light paths can be made substantially the same, the fluorescent material 227 needs to be uniformly dispersed in the resin 223, and it is difficult to completely control the fluorescent material 227. Therefore, in a portion where the amount of the phosphor 227 is small, sufficient excitation light emission cannot be obtained, and thus bluish light is emitted, which is insufficient to obtain uniform mixed light.

JP 2000-208815 A JP 2002-222996 A

  Accordingly, an object of the present invention is to provide a light emitting device capable of irradiating uniform light on an irradiation surface.

  According to the present invention, the above problem is solved by the following means.

  The present invention provides a base having a concave portion having a bottom surface and a side surface, a light emitting element placed on the bottom surface of the concave portion of the base, and covers the light emitting element, and is disposed in the concave portion of the base. A first member; a light diffusing member that covers the first member, is disposed in the recess of the base, and diffuses light from the light emitting element; and includes a side surface of the base The present invention relates to a light emitting device having a second member in the vicinity of the upper part of the light emitting element rather than the vicinity thereof and containing a large amount of the light diffusing member in the same volume. Accordingly, a light emitting device that can irradiate uniform light on the irradiation surface can be provided.

  The present invention provides a base having a concave portion having a bottom surface and a side surface, a light emitting element placed on the bottom surface of the concave portion of the base, and covers the light emitting element, and is disposed in the concave portion of the base. A first member; a light diffusing member that covers the first member, is disposed in the recess of the base, and diffuses light from the light emitting element; and includes a side surface of the base And a second member having a thickness near the upper portion of the light emitting element that is thicker than a thickness near the light emitting device. Accordingly, a light emitting device that can irradiate uniform light on the irradiation surface can be provided.

The thickness of the second member above the light emitting element is preferably thicker than the thickness of the first member above the light emitting element. This is for diffusing light emitted from above the light emitting element. Moreover, it is for diffusing the light reflected by the side surface of the recessed part of a base.
It is preferable that the first member is filled to a position lower than the upper end of the recess. This is because it is easy to arrange the second member.
As the concave portion, a step having a step on the side surface and the first member disposed on the lower portion can be used. This is because it is easy to arrange the first member, and it is also easy to arrange the second member. In addition, a certain amount of the second member is secured to further promote light diffusion.
As the first member and the second member, those fixed without any interface can be used. Thereby, the fall of the light extraction efficiency by a refractive index difference can be suppressed. However, even if an interface is generated when the second member is disposed in a state where the first member is semi-cured, it is not an interface in the present specification. The interface in this specification refers to what occurs when the second member is disposed in a state where the first member is fully cured.
The first member may include a fluorescent material that absorbs light from the light emitting element and emits light having a wavelength different from that of the light from the light emitting element. Thereby, when the light from the light emitting element and the light wavelength-converted by the first member pass through the second member and are extracted to the outside, light with high color mixing property can be extracted.
The first member is preferably formed in a concave shape. Since the second member can be disposed in the concave portion of the first member, light diffusion can be improved.
The second member is preferably formed in a convex shape protruding from the concave portion of the base. Since the light diffusing member is included in the second member, the light-diffusing action is easily improved in the portion having a thick convex shape than in the portion having a small thickness.
The light emitting device may further include a third member on the second member. Thereby, the second member can be protected. Moreover, the light extraction efficiency can be improved by using a third member having a lower refractive index than the second member. The third member preferably has a small or no amount of the light diffusing member in order to enhance the effect of condensing light.

  The present invention includes a base having a recess having a bottom surface and side surfaces, a light emitting element placed on the bottom surface of the recess of the base, a first member covering the light emitting element, and a light diffusion member And a second member that covers the first member, the first step of placing the light emitting element on the bottom surface of the base, and the inside of the recess And a second step of disposing the first member on the first member such that the thickness near the upper side of the light emitting element is thicker than the thickness near the side surface of the base. And a third step of disposing the substrate. Thereby, a light emitting device having a high light diffusion effect can be easily manufactured. The third step can be manufactured by using a resin having a high viscosity or by providing a member having high water repellency at a predetermined position.

  In the second step, it is preferable that the first member is hardened and arranged to be concave. Thereby, the thickness of the second member can be easily changed.

  In the third step, the second member is preferably disposed before the first member is fully cured. As a result, the interface between the first member and the second member can be eliminated, and a decrease in light extraction efficiency associated with light reflection at the interface can be suppressed. Moreover, the adhesiveness of the 1st member and the 2nd member can be improved.

  In the third step, it is preferable that a second member is dropped from above the light emitting element to form a convex shape protruding from the concave portion. Thereby, the second member having a predetermined thickness can be easily formed.

  ADVANTAGE OF THE INVENTION According to this invention, the light-diffusion effect | action can be improved and the light-emitting device which can irradiate the uniform light in an irradiation surface can be provided.

  Hereinafter, a light-emitting device and a manufacturing method thereof according to the present invention will be described with reference to embodiments and examples. However, the present invention is not limited to this embodiment and examples.

<First Embodiment>
The light emitting device according to the first embodiment has the following configuration. FIG. 1 is a schematic cross-sectional view showing the light emitting device according to the first embodiment. FIG. 2 is a schematic diagram illustrating an image of an irradiation surface when the light emitting device according to the first embodiment emits light.
The light emitting device according to the first embodiment is a so-called bullet-type light emitting device including the light emitting element 1, the base 2, the first member 3, and the second member 4. The base 2 on the side on which the light emitting element 1 is placed has a recess 2a having a bottom surface 2b and a side surface 2c. The light emitting element 1 is placed on the bottom surface 2 b of the recess 2 a of the base 2. The first member 3 is disposed in the recess 2 a of the base 2 and covers the light emitting element 1. The center of the first member 3 is recessed. The second member 4 can be disposed in the recess 2 a of the base 2 by denting the central portion. The second member 4 contains a light diffusing member 5. The second member 4 is disposed in the recess 2 a or in the vicinity of the recess 2 a and covers the first member 3. The center part of the second member 4 is formed in a convex shape. That is, the thickness near the upper side of the light emitting element 1 is thicker than the thickness near the side surface 2 c of the base 2. When the light diffusing member 5 is contained almost uniformly in the second member 4, the light diffusing member 5 in the upper part of the light emitting element 1 is larger than the total amount of the light diffusing member 5 in the vicinity of the side surface 2 c of the base 2. Since the total amount of is large, the light diffusion effect is large. The second member 4 is further covered with a third member 6. The third member 6 fixes the base 2.
(Function)
The light emitted from above the light emitting element 1 is irradiated and reflected on the light diffusion member 5 included in the second member 4, and the light is diffused. Since the total amount of the light diffusing member 5 in the upper part of the light emitting element 1 is larger than the total amount of the light diffusing member 5 in the vicinity of the side surface 2c of the base 2, the light diffusing action is large. The light emitted from the side surface of the light emitting element 1 is reflected by the side surface 2 c of the recess 2 a of the base 2 and passes through the upper part of the light emitting element 1. Also at this time, since the total amount of the light diffusing member 5 in the upper part of the light emitting element 1 is larger than the total amount of the light diffusing member 5 in the vicinity of the side surface 2c of the base 2, the light diffusing action is large. The first light 101 emitted from above the light emitting element 1 and diffused by the light diffusing member 5 and the second light 102 emitted from the side surface of the light emitting element 1 and diffused by the light diffusing member 5 Mix. As a result, light can be diffused by arranging a large number of light diffusing members 5 in a portion where the amount of light transmitted is large, so that a light emission color that is more uniform than the conventional one can be copied on the irradiated surface. In addition, since the portion where the light is diffused is limited, it is possible to suppress a decrease in light emission output.

<Second Embodiment>
A second embodiment will be described with reference to the drawings. FIG. 3 is a schematic cross-sectional view showing a light emitting device according to the second embodiment.
The second embodiment employs substantially the same configuration as that of the first embodiment except that the fluorescent material 17 is contained in the first member 13. There is also a part which omits description about the part which takes about the same composition. The light emitting device according to the second embodiment is a so-called bullet-type light emitting device including the light emitting element 11, the base 12, the first member 13, and the second member 14. The first member 13 contains a fluorescent material 17 and settles in the recess of the base 12. The first member 13 is disposed in the recess of the base 12 and covers the light emitting element 11. The fluorescent material 17 is disposed on the upper surface or side surface of the light emitting element 11. The center part of the first member 13 is recessed. The second member 14 contains a light diffusing member 15. The second member 14 is disposed in the recess or in the vicinity of the recess and covers the first member 13. The center part of the second member 14 is formed in a convex shape. That is, the thickness near the upper side of the light emitting element 11 is thicker than the thickness near the side surface of the base 12. When the light diffusing member 15 is contained almost uniformly in the second member 14, the light diffusing member 15 in the upper part of the light emitting element 11 is larger than the total amount of the light diffusing member 15 in the vicinity of the side surface of the base 12. Since the total amount is large, the light diffusion effect is large. The second member 14 is further covered with a third member 16. The third member 16 fixes the base 12.
(Function)
At least a part of the light emitted from the light emitting element 11 is irradiated to the fluorescent material 17 and emits light having a wavelength different from that of the light from the light emitting element 11. The light emitted from above the light emitting element 11 (the light from the light emitting element 11 and the light from the fluorescent material 17) is irradiated and reflected on the light diffusion member 15 included in the second member 14, and the light is diffused. To do. Since the total amount of the light diffusing member 15 in the upper part of the light emitting element 11 is larger than the total amount of the light diffusing member 15 in the vicinity of the side surface of the base 12, the light diffusing action is large. In addition, light emitted from the side surface of the light emitting element 11 (light from the light emitting element 11 and light from the fluorescent material 17) is reflected by the side surface of the recess of the base 12 and passes through the upper part of the light emitting element 11. . Also at this time, since the total amount of the light diffusing member 15 in the upper part of the light emitting element 11 is larger than the total amount of the light diffusing member 15 in the vicinity of the side surface of the base 12, the light diffusing action is large. Accordingly, since the light diffusion member 15 can be arranged in a large amount to diffuse the light in the portion where the amount of light transmission is large, it is possible to emit a light emission color that is more uniform than in the past. And since the part to which light is diffused is limited, the fall of light emission output can also be suppressed. For example, a gallium nitride compound semiconductor that emits blue light is used for the light emitting element 11, and an yttrium, aluminum, and oxide phosphor that emits yellow light is used for the fluorescent material 17. In the first member 13, when the light emitted from above the light emitting element 11 is blue light, and the light emitted from the vicinity of the side surface of the base 12 is mainly yellow light, the second light as described above. Since light is diffused by the member 14, uniform white light is projected on the irradiated surface. Thereby, generation | occurrence | production of donut-shaped yellow ring can be suppressed.

<Third Embodiment>
A third embodiment will be described with reference to the drawings. FIG. 4 is a schematic cross-sectional view showing a light emitting device according to the third embodiment. FIG. 5 is a schematic diagram showing an image of an irradiation surface when the light emitting device according to the third embodiment is caused to emit light.
The third embodiment is different from the first embodiment except that the first member 23 contains the fluorescent material 27 and the concentration of the light diffusion member 25 contained in the second member 24 is changed. The configuration is almost the same as that of the embodiment. There is also a part which omits description about the part which takes about the same composition. The light emitting device according to the third embodiment is a so-called bullet-type light emitting device including the light emitting element 21, the base 22, the first member 23, and the second member 24. The first member 23 contains a fluorescent material 27 and settles in the recess of the base 22. The first member 23 is disposed in the recess of the base 22 and covers the light emitting element 21. The fluorescent material 27 is disposed on the upper surface or side surface of the light emitting element 21. The central portion of the first member 23 is recessed. The second member 24 contains a light diffusing member 25. The second member 24 is disposed in the recess or in the vicinity of the recess and covers the first member 23. More light diffusion members 25 are contained in the same volume in the vicinity of the upper side of the light emitting element 21 than in the vicinity of the side surface of the base 22. As a result, the light diffusing action is greater near the upper side of the light emitting element 21 than near the side surface of the base 22. As long as the light diffusion member 25 is contained in the same volume in the vicinity of the upper side of the light emitting element 21 than in the vicinity of the side surface of the base 22, the second member 24 may have a flat plate shape or a central portion may have a convex shape. . Here, the central portion of the second member 24 is formed in a convex shape. The second member 24 is further covered with a third member 26. The third member 26 fixes the base 22.
The first light 111 emitted from above the light emitting element 21 and diffused by the light diffusing member 25 and the second light 112 emitted from the side surface of the light emitting element 21 and diffused by the light diffusing member 25 Mix. Also by this, since light is diffused by the second member 24, uniform white light is projected on the irradiated surface. In addition, the occurrence of a donut-shaped yellow ring can be suppressed.

<Fourth embodiment>
A fourth embodiment will be described with reference to the drawings. FIG. 6 is a schematic cross-sectional view showing a light emitting device according to the fourth embodiment.
The fourth embodiment is the same as that of the first embodiment except that the first member 33 contains the fluorescent material 37 and that the surface of the second member 34 is substantially the same as the upper end of the recess. The configuration is almost the same as the form. There is also a part which omits description about the part which takes about the same composition. The light emitting device according to the fourth embodiment is a so-called bullet-type light emitting device including a light emitting element 31, a base 32, a first member 33, and a second member 34. The first member 33 contains a fluorescent material 37 and settles in the recess of the base 32. The first member 33 is disposed in the recess of the base 32 and covers the light emitting element 31. The fluorescent material 37 is disposed on the upper surface or side surface of the light emitting element 31. The central portion of the first member 33 is recessed. The second member 34 includes a light diffusing member 35. The second member 34 is disposed in the recess or in the vicinity of the recess and covers the first member 33. The surface of the second member 34 is formed flat. As for the thickness of the second member 34, the thickness near the upper side of the light emitting element 31 is thicker than the thickness near the side surface of the base 32. When the light diffusing member 35 is contained almost uniformly in the second member 34, the light diffusing member 35 in the upper part of the light emitting element 31 is larger than the total amount of the light diffusing member 35 in the vicinity of the side surface of the base 32. Since the total amount is large, the light diffusion effect is large. The second member 34 is further covered with a third member 36. The third member 36 fixes the base 12.
Thus, although not shown in the drawing, the light emitted from above the light emitting element 31 and diffused by the light diffusing member 35, the light emitted from the side surface of the light emitting element 31, etc., and diffused by the light diffusing member 35. Light can be mixed, and a more uniform emission color than before can be emitted. Also by this, since light is diffused by the second member 34, uniform white light is projected on the irradiated surface. Also, the occurrence of a donut-shaped yellow ring can be suppressed. Furthermore, since the flat surface of the second member 34 limits the portion where the light is diffused, it is possible to further suppress the decrease in the light emission output. In addition, manufacturing is easier than making the surface of the second member 34 convex, and the burden on the wire can also be reduced.

<Fifth embodiment>
A fifth embodiment will be described with reference to the drawings. FIG. 7 is a schematic cross-sectional view showing a light emitting device according to a fifth embodiment.
In the fifth embodiment, the fluorescent material 47 is dispersed substantially uniformly in the first member 43, the surface of the first member 43 is flat, and the surface of the second member 44 is The configuration is almost the same as that of the first embodiment except that it is convex. There is also a part which omits description about the part which takes about the same composition. The light emitting device according to the fifth embodiment is a so-called bullet-type light emitting device including a light emitting element 41, a base 42, a first member 43 and a second member 44. The first member 43 contains a fluorescent material 47 and is distributed substantially uniformly in the recesses of the base 42. The first member 43 is disposed in the recess of the base 42 and covers the light emitting element 41. The first member 43 has a flat surface. The second member 44 includes a light diffusing member 45. The second member 44 is disposed above or near the recess than the recess, and covers the first member 43. The surface of the second member 44 is formed in a convex shape. The thickness of the second member 44 is thicker in the vicinity of the upper side of the light emitting element 41 than in the vicinity of the side surface of the base 42. When the light diffusing member 45 is contained substantially uniformly in the second member 44, the light diffusing member 45 in the upper part of the light emitting element 41 is larger than the total amount of the light diffusing member 45 in the vicinity of the side surface of the base 42. Since the total amount is large, the light diffusion effect is large. The second member 44 is further covered with a third member 46. The third member 46 fixes the base 42.
Thereby, although not shown in the drawing, the light emitted from above the light emitting element 41 and diffused by the light diffusion member 45 and the light emitted from the side surface of the light emitting element 31 and the like and diffused by the light diffusion member 45 And can emit a light emission color that is more uniform than in the prior art as in the second embodiment. Further, by dispersing the fluorescent material 47 substantially uniformly in the first member 43, the light from the light emitting element 41 and the light converted into the wavelength of the fluorescent material 47 can be easily mixed, and more uniform light emission. A color can be emitted.
Also by this, since light is diffused by the second member 34, more uniform white light is projected on the irradiated surface. Also, the occurrence of a donut-shaped yellow ring can be suppressed.

<Sixth Embodiment>
A sixth embodiment will be described with reference to the drawings. FIG. 8 is a schematic cross-sectional view showing a light emitting device according to a sixth embodiment.
In the sixth embodiment, a fluorescent material 57 is contained in the first member 53, and the surface of the first member 53 and the surface of the second member 54 are convex. In addition, a member that repels resin is applied to the upper end of the concave portion of the base 52, and the wire is not applied to the depressed portion. Other than that, the configuration is almost the same as that of the first embodiment. There is also a part which omits description about the part which takes about the same composition. The light emitting device according to the sixth embodiment is a so-called bullet-type light emitting device including a light emitting element 51, a base 52, a first member 53, and a second member 54. The first member 53 contains a fluorescent material 57 and has settled in the recess of the base 52. The first member 53 is disposed in the recess of the base 52 and covers the light emitting element 51. The fluorescent material 57 is disposed on the upper surface or side surface of the light emitting element 51. The surface of the first member 53 has a convex shape. The second member 54 includes a light diffusing member 55. The second member 54 is disposed above or near the recess, and covers the first member 53. The second member 54 prevents the resin from flowing to the portion where the wire is bonded by the member that repels the resin applied to the upper end of the recess. Thereby, the surface of the second member 54 can be formed in a convex shape. The thickness of the second member 54 is thicker in the vicinity of the upper part of the light emitting element 51 than in the vicinity of the side surface of the base 52. When the light diffusing member 55 is contained almost uniformly in the second member 54, the light diffusing member 55 in the upper part of the light emitting element 51 is larger than the total amount of the light diffusing member 55 in the vicinity of the side surface of the base 52. Since the total amount is large, the light diffusion effect is large. The second member 54 is further covered with a third member 56. The third member 56 fixes the base 52.
As a result, although not shown in the drawing, the light emitted from above the light emitting element 51 and diffused by the light diffusing member 55, the light emitted from the side surface of the light emitting element 51, etc., and diffused by the light diffusing member 55. Light can be mixed, and a more uniform emission color than before can be emitted. Furthermore, since the convex surfaces of the first and second members limit the portion where light is diffused, it is possible to further suppress a decrease in light emission output, and in particular, the light is emitted from the vicinity of the end of the concave portion. A decrease in light output can be suppressed.
Also by this, since light is diffused by the second member 54, uniform white light is projected on the irradiated surface. Also, the occurrence of a donut-shaped yellow ring can be suppressed.

<Seventh embodiment>
A seventh embodiment will be described with reference to the drawings. FIG. 9 is a schematic cross-sectional view showing a light emitting device according to a seventh embodiment.
The seventh embodiment is substantially the same as the fifth embodiment except that the second member 64 is slightly thin and the concentration of the light diffusing member 65 contained in the second member 64 is changed. The configuration of There is also a part which omits description about the part which takes about the same composition. The light emitting device according to the seventh embodiment is a so-called bullet-type light emitting device including a light emitting element 61, a base 62, a first member 63, and a second member 64. The first member 63 contains a fluorescent material 67 and is dispersed substantially uniformly in the recesses of the base 62. The first member 63 is disposed in the recess of the base 62 and covers the light emitting element 61. The first member 63 has a flat surface. The second member 64 includes a light diffusing member 65 and is disposed above or near the recess than the recess and covers the first member 63. In addition, the second member 64 contains more light diffusing members 65 in the same volume near the upper side of the light emitting element 61 than near the side surface of the base 62. Therefore, the light diffusion action is greater near the upper side of the light emitting element 61 than near the side surface of the base 62. Therefore, even if the thickness of the second member 64 is relatively thin, light can be diffused sufficiently uniformly. The second member 64 has a convex central portion and is covered with a third member 66. The third member 66 fixes the base 62.
Thereby, although not shown in the drawing, the first light emitted from above the light emitting element 61 and diffused by the light diffusing member 65 and the side surface of the light emitting element 61 are emitted as in the fifth embodiment. Then, the second light diffused by the light diffusion member 25 is mixed. Further, by dispersing the fluorescent material 47 substantially uniformly in the first member 43, the light from the light emitting element 41 and the light converted into the wavelength of the fluorescent material 47 can be easily mixed, and more uniform light emission. A color can be emitted. Furthermore, reducing the thickness of the second member 64 limits the portion where the light is diffused, so that a decrease in light emission output can be further suppressed, and the burden on the wire can be reduced. Become.
Also by this, since the light is diffused by the second member 64, uniform white light is projected on the irradiated surface. In addition, the occurrence of a donut-shaped yellow ring can be suppressed.

<Eighth Embodiment>
The eighth embodiment will be described with reference to the drawings. FIG. 10 is a schematic cross-sectional view showing a light emitting device according to the eighth embodiment.
In the eighth embodiment, a second step is provided except that a step is provided in the recess of the base 72, the first member 73 is disposed in the lower step portion, and the second member 74 is disposed in the upper step portion. The configuration is almost the same as that of the embodiment. There is also a part which omits description about the part which takes about the same composition. The light emitting device according to the eighth embodiment is a so-called bullet type light emitting device including a light emitting element 71, a base 72, a first member 73, and a second member 74. A fluorescent material 77 is contained in the first member 73, and settles in the lower part of the base 72. The first member 73 is disposed on the lower stage portion of the base 72 and covers the light emitting element 71. The fluorescent material 77 is disposed on the upper surface or side surface of the light emitting element 71. The central portion of the first member 73 is recessed. The second member 74 contains a light diffusing member 75. The second member 74 is disposed in the upper step portion of the recess or in the vicinity of the upper step portion of the recess, and covers the first member 73. The center part of the second member 74 is formed in a convex shape. That is, the thickness near the upper side of the light emitting element 71 is thicker than the thickness near the side surface of the base 72. When the light diffusing member 75 is contained almost uniformly in the second member 74, the light diffusing member 75 in the upper part of the light emitting element 71 is larger than the total amount of the light diffusing member 75 in the vicinity of the side surface of the base 72. Since the total amount is large, the light diffusion effect is large. The second member 74 is further covered with a third member 76. The third member 76 fixes the base 72.
Thereby, although not shown in the drawing, the first light emitted from above the light emitting element 71 and diffused by the light diffusing member 75 and the side surface of the light emitting element 71 and the like, as in the second embodiment. Then, the second light diffused by the light diffusing member 75 is uniformly mixed. Also by this, since light is diffused by the second member 74, uniform white light is projected on the irradiated surface, and the occurrence of a donut-shaped yellow ring can also be suppressed.
Further, in the eighth embodiment, even when a low-viscosity member is used as the second member 74, the second member 74 is reliably disposed in the recess by the step provided on the base 72. Can do. The steps provided on the base 72 can be easily manufactured because the steps may be arranged using the step portions as a guideline in the manufacturing process in which the first and second members are poured. Further, the second member 74 can be poured into the first member 73 in a semi-cured state so that an interface is not formed. The level difference of the base 72 suppresses the light from the semiconductor element from hitting the contact portion between the second member 74 and the base 72 in order to suppress the deterioration of the second member 74. Further, the level difference of the base 72 increases the surface area of the portion where the second member 74 and the base 72 are in contact. As a result, the second member 74 can also be prevented from peeling from the base 72.

<Ninth embodiment>
A ninth embodiment will be described with reference to the drawings. FIG. 11 is a schematic cross-sectional view showing a light emitting device according to the ninth embodiment.
In the ninth embodiment, the surfaces of the first and second members are flat, the fluorescent material 87 is substantially uniformly dispersed in the first member 83, and the second member 84. Except that the concentration of the light diffusing member 85 contained in is changed, the configuration almost the same as that of the eighth embodiment is adopted. There is also a part which omits description about the part which takes about the same composition. The light emitting device according to the ninth embodiment is a so-called bullet-type light emitting device including a light emitting element 81, a base 82, a first member 83, and a second member 84. The first member 83 contains a fluorescent material 87 and settles in the lower part of the base 82. The first member 83 is disposed at the lower part of the base 82 and covers the light emitting element 81. The surface of the first member 83 is flat. The second member 84 includes a light diffusing member 85. The second member 84 is disposed in the upper step of the recess or in the vicinity of the upper step of the recess and covers the first member 83. In addition, the second member 84 has the same volume in the vicinity of the upper side of the light emitting element 81 than the vicinity of the side surface of the base 82, and contains more light diffusion members 65. Therefore, the light diffusion action is greater near the upper side of the light emitting element 81 than near the side surface of the base 82. Therefore, even if the thickness of the second member 84 is relatively thin, light can be diffused sufficiently uniformly. The second member 84 has a central portion formed in a convex shape, and is further covered with a third member 86. The third member 86 fixes the base 82.
As a result, although not shown in the drawing, as in the eighth embodiment, the first light emitted from above the light emitting element 81 and diffused by the light diffusing member 85 and the side surface of the light emitting element 81 are emitted. Then, the second light diffused by the light diffusing member 85 is uniformly mixed. Further, flattening the surface of the first and second members 84 and reducing the thickness limits the portion where the light is diffused, and thus can further suppress the decrease in the light emission output, and the burden on the wire. Can also be reduced. Also by this, since the light is diffused by the second member 84, uniform white light is projected on the irradiated surface, and the occurrence of a donut-shaped yellow ring can be suppressed.
In the ninth embodiment, even if a low-viscosity member is used as the second member 84, the second member 84 is reliably disposed in the recess by the step provided on the base 82. Can do. The steps provided on the base 82 can be easily manufactured because the steps may be arranged with reference to the steps in the manufacturing process in which the first and second members are poured. Further, the manufacturing of the first and second members is further facilitated by flattening the surfaces. The second member 84 can be poured into the first member 83 in a semi-cured state so that no interface can be formed. The level difference of the base 72 suppresses the light from the semiconductor element from hitting the contact portion between the second member 84 and the base 82 in order to suppress the deterioration of the second member 84. Further, the level difference of the base 82 increases the surface area of the portion where the second member 84 and the base 82 are in contact. As a result, the second member 84 can also be prevented from peeling off from the base 82.

  Hereinafter, what is used by the said structural member is demonstrated in detail. However, the following member is an example, and the present invention is not limited to this.

(Light emitting element)
As the light-emitting element, a substrate in which a semiconductor such as GaAlN, ZnS, ZnSe, SiC, GaP, GaAlAs, AlN, InN, AlInGaP, InGaN, GaN, or AlInGaN is formed as a light-emitting layer can be used. Examples of the semiconductor structure include a homo structure having a MIS junction, a PIN junction, and a PN junction, a hetero structure, and a double hetero structure. Various emission wavelengths can be selected from ultraviolet light to infrared light depending on the material of the semiconductor layer and the degree of mixed crystal. The light emitting layer may have a single quantum well structure or a multiple quantum well structure which is a thin film in which a quantum effect is generated. A light emitting element having an electrode on the same surface side is used, but a light emitting element having electrodes on the upper and lower surfaces can also be used. Further, the light emitting element can be mounted face-down on the base without using a wire.
The number of light emitting elements is not limited to one, and a plurality of light emitting elements can be used. By combining a plurality of light emitting elements, color mixing in white display can be improved.
A light emitting element that emits light from ultraviolet to infrared light can be used, but a light emitting element that emits visible light is preferable. The light-emitting element is appropriately changed depending on the absorption spectrum, emission spectrum, emission color of the light-emitting device, and the like, but the emission peak wavelength is preferably 360 nm to 470 nm. This is because when the emission peak wavelength is 300 nm or less, the first member and the second member that hold the fluorescent material are deteriorated.

(Base)
The base has a recess. The base is not limited to a lead used in a bullet-type light emitting device, but can be applied to a package using resin or ceramics. For the lead, a member having good electrical conductivity is used. A light emitting element is placed on the bottom surface of the recess of the base. The side surface of the recess of the base reflects light from the light emitting element and emits light upward. A reflection angle is provided so that the light reflected by the side surface of the recess of the base passes above the light emitting element. The depth of the concave portion of the base has such a depth that the first member can be covered on the light emitting element. A member that repels the first member or the second member can be disposed at the upper end of the recess of the base.
The base can also form a recess having one or more steps. This is because the first member and the second member are disposed in the recess. In addition, the second member can be disposed in a state where the first recess is semi-cured. The plurality of recesses are preferably formed in a step shape so as to expand in the opening direction.
(First member)
The first member is formed in the recess of the base and covers the light emitting element. The first member can also contain a fluorescent material. As a specific material constituting the first member, an epoxy resin, a silicone resin, a modified silicone resin, an acrylic resin, an imide resin, a urea resin, or the like can be used. Among these, an epoxy resin and a silicone resin are preferable. It is because it is excellent in heat resistance and light resistance. The first member can be formed into a concave shape, a convex shape, a flat shape, or the like by adjusting, for example, the viscosity or volatility of the resin, dropping conditions, and the like. The first member preferably has a higher refractive index than the second member. This is because the light extraction efficiency can be increased.

(Fluorescent substance)
The fluorescent substance may be any substance that absorbs light from the light emitting element and converts the wavelength into light of a different wavelength. For example, it is mainly activated by nitride-based phosphors / oxynitride-based phosphors mainly activated by lanthanoid elements such as Eu and Ce, lanthanoid-based phosphors such as Eu, and transition metal elements such as Mn. Alkaline earth halogen apatite phosphor, alkaline earth metal borate phosphor, alkaline earth metal aluminate phosphor, alkaline earth silicate, alkaline earth sulfide, alkaline earth thiogallate, alkaline earth nitriding Selected from silicon, germanate, or rare earth aluminate mainly activated by lanthanoid elements such as Ce, organic and organic complexes mainly activated by lanthanoid elements such as rare earth silicate or Eu It is preferable that it is at least any one or more. Of these, description will be made using yttrium aluminum oxide activated by Ce, but is not limited thereto.

(Second member)
The second member covers the first member. The second member contains a light diffusing member. As a specific material constituting the second member, an epoxy resin, a silicone resin, a modified silicone resin, an acrylic resin, an imide resin, a urea resin, or the like can be used, and it is particularly preferable to use an epoxy resin or a silicone resin. . Moreover, it is preferable to use the same kind of member for the first member and the second member. By using the same type of member, the adhesion between the first member and the second member can be improved, or the interface can be eliminated. The second member can change the light diffusion state by adjusting the thickness of the second member and the content of the light diffusion member. Further, the shape of the second member can be changed by adjusting, for example, the viscosity and volatility of the resin, dropping conditions, and the like. Further, the second member can also be formed in a convex shape protruding from the concave portion of the base. The second member is preferably disposed in the recess of the base, but may protrude from the recess of the base. It is preferable that the second member is uniformly dispersed before being dropped into the recess of the base. This is because the total amount of the light diffusing member contained in the second member can always be made uniform, and color variation for each product can be reduced. In addition, as the second member, two or more members containing light diffusing members having different concentrations can be used. The concentration of the second member can be changed by disposing a resin having a high concentration of the light diffusing member above the light emitting element and disposing a resin having a low concentration of the light diffusing member on the side surface of the recess of the base. A third member can be further disposed on the second member. Furthermore, when arrange | positioning a 3rd member, the one where a refractive index is lower than a 2nd member is preferable. This is because the light extraction efficiency can be increased.

(Light diffusion member)
The light diffusing member is contained in the second member. As specific materials constituting the light diffusing member, inorganic diffusing materials such as silicon dioxide, titanium oxide, aluminum oxide, calcium carbonate, zinc oxide, and barium titanate are desirable. Organic diffusion materials such as epoxy resin, phenol formalin resin, benzoguanamine resin, melamine resin, acrylic resin, polycarbonate resin, polyethylene resin, polypropylene resin, and guanamine resin may be used. Glass or the like can also be used. Of these, silicon dioxide and titanium oxide having high reflectivity are preferable. The light diffusion effect can be adjusted by the content of the light diffusion member.

(Third member)
The third member protects the first member, the light emitting element, and the like from external force and moisture from the external environment. Therefore, it is desirable that it is harder than the second member. In addition, light from the light emitting element can be efficiently collected and emitted to the outside. Such a specific material constituting the third member is produced by a sol-gel method using a transparent resin having excellent weather resistance such as an epoxy resin, a urea resin, a silicone resin, or a metal alkoxide as a starting material. A translucent inorganic member, glass or the like is preferably used. Among these, an epoxy resin is preferable from the viewpoint of strength and ease of molding. Further, organic or inorganic coloring dyes or coloring pigments may be included for the purpose of cutting a predetermined wavelength. Moreover, in order to further diffuse light, a light diffusing member can be contained.

(Method for manufacturing light emitting device)
A method for manufacturing the light emitting device according to the embodiment will be described. A light emitting device according to the second embodiment will be described.
The light emitting device according to the second embodiment includes a base 12 having a recess having a bottom surface and a side surface, a light emitting element 11 placed on the bottom surface of the recess of the base 12, and a first covering the light emitting element 11. 1 member 13 and a second member 14 containing the light diffusion member 15 and covering the first member 13.
The light emitting element 11 is placed on the bottom surface of the base 12 having a recess having a bottom surface and a side surface (first step). The light emitting element 11 is fixed via an epoxy resin or a metal member. Then, the light emitting element 11 and the base 12 are electrically connected through a wire.
Next, the 1st member 13 is arrange | positioned in the recessed part of the base 12 (2nd process). The first member 13 contains a fluorescent material 17 uniformly dispersed in advance. When the first member 13 is placed in the recess of the base 12 and then placed, the fluorescent material 17 settles. It is preferable to perform the next step after semi-curing or main-curing the first member 13. As the first member 13 is cured, the organic component is volatilized, the central portion is recessed, and a concave shape is formed. In particular, it is possible to easily form a concave shape by using the first member 13 having high volatility. Alternatively, the first member 13 can be formed in a concave shape by dropping a small amount.
Next, the second member 14 is disposed on the first member 13 so that the thickness near the upper side of the light emitting element 11 is thicker than the thickness near the side surface of the base 12 (third step). . By using the second member 14 having a high viscosity, it can be easily formed. Further, a resin repelling member can be applied to the upper end of the recess of the base 12. The second member 14 is preferably dropped from above the light emitting element 11. The second member 14 contains a light diffusing member 15 uniformly dispersed in advance.
The second member 14 can be disposed before the first member 13 is fully cured. Thereby, it can harden | cure without forming an interface between the 1st member 13 and the 2nd member 14, and it can raise the extraction efficiency of light. Moreover, after inject | pouring the 1st member 13, the 2nd member 14 is dripped and the 1st member 13 and the 2nd member 14 are also hardened by hardening the 1st member 13 and the 2nd member 14 simultaneously. It is possible to cure without forming an interface with the member 14. On the other hand, after the first member 13 is fully cured, the second member 14 can be cured. The first member 13 and the second member 14 having different refractive indexes can be used, or members of different materials can be used. Furthermore, a third member 16 is provided. The resin related to the third member 16 is injected into a jig having a predetermined opening. Thereafter, a part of the base 12 is immersed in the opening of the jig so that the second member 14 is covered. After the third member 16 is temporarily cured, the base 12 is taken out from the healing portion, and the third member 16 is fully cured.
A light emitting device can be manufactured through the above steps.

Example 1
Example 1 takes substantially the same form as the second embodiment. There is also a part which abbreviate | omits description about the part which takes the same structure. Example 1 will be described with reference to FIG. Example 1 includes a light emitting element 11, a base 12, a first member 13, a second member 14, a light diffusing member 15, a third member 16, and a fluorescent material 17.
The light emitting element 11 is placed in a recess (cup part) of a base (lead frame) 12. The light emitting element 11 uses a gallium nitride compound semiconductor. The recess of the base 12 has a depth of about 0.3 mm.
The first member 13 is disposed in the recess of the base 12 and covers the light emitting element 11. The first member 13 is formed in a concave shape from the upper end in the concave portion of the base 12 to the vicinity of the upper side of the light emitting element 11. The first member 13 is approximately 0.1 mm lower in the vicinity of the upper side of the light emitting element 11 than the upper end of the concave portion of the base 12. The first member 13 is made of an epoxy resin and contains a fluorescent material 17.
The fluorescent material 17 is disposed on the upper surface or side surface of the light emitting element 11. The fluorescent substance 17 uses a YAG-based phosphor.
The second member 14 covers the first member 13 and is disposed in the recess of the base 12 or in the vicinity of the recess. The surface of the second member 14 is formed in a convex shape, and is about 0.2 mm higher in the vicinity of the upper side of the light emitting element 11 than the upper end of the concave portion of the base 12. Therefore, the thickness of the second member 14 near the upper side of the light emitting element 11 is about 0.3 mm. As a result, the thickness of the second member 14 near the upper side of the light emitting element 11 is thicker than the thickness near the side surface of the base 12. The second member 14 uses an epoxy resin, and the light diffusion member 15 is contained substantially uniformly.
The third member 16 covers the second member 14 so as to fix the base 12. An epoxy resin is used for the third member 16. The third member 16 is formed so as to have a shape of a commercially available bullet-type light emitting device.
The light emitting device manufactured as described above can emit uniform white light.

It is a schematic sectional drawing which shows the light-emitting device which concerns on 1st Embodiment. It is the schematic which shows the image of the irradiation surface at the time of making the light-emitting device which concerns on 1st Embodiment light-emit. It is a schematic sectional drawing which shows the light-emitting device which concerns on 2nd Embodiment. It is a schematic sectional drawing which shows the light-emitting device which concerns on 3rd Embodiment. It is the schematic which shows the image of the irradiation surface at the time of making the light-emitting device which concerns on 3rd Embodiment light-emit. It is a schematic sectional drawing which shows the light-emitting device which concerns on 4th Embodiment. It is a schematic sectional drawing which shows the light-emitting device which concerns on 5th Embodiment. It is a schematic sectional drawing which shows the light-emitting device which concerns on 6th Embodiment. It is a schematic sectional drawing which shows the light-emitting device concerning 7th Embodiment. It is a schematic sectional drawing which shows the light-emitting device concerning 8th Embodiment. It is a schematic sectional drawing which shows the light-emitting device concerning 9th Embodiment. It is a schematic sectional drawing which shows the conventional light-emitting device. It is the schematic which shows the image of the irradiation surface at the time of making the conventional light-emitting device light-emit. It is a schematic sectional drawing which shows the conventional light-emitting device.

Explanation of symbols

1, 11, 21, 31, 41, 51, 61, 71, 81 Light-emitting element 2, 12, 22, 32, 42, 52, 62, 72, 82 Base 3, 13, 23, 33, 43, 53, 63, 73, 83 First member 4, 14, 24, 34, 44, 54, 64, 74, 84 Second member 5, 15, 25, 35, 45, 55, 65, 75, 85 Light diffusing member 6, 16, 26, 36, 46, 56, 66, 76, 86 Third member 17, 27, 37, 47, 57, 67, 77, 87 Fluorescent substance 101, 111 First light 102, 112 Second light 201, 221 Light emitting element 202, 222 Lead frame 203 Coating resin 206, 226 Mold member 207, 227 Phosphor 211 Blueish white light 212 Yellowish white light 223 Resin 224 Diffusion resin 2 5 diffusion member

Claims (14)

A base having a recess having a bottom surface and a side surface;
A light emitting element placed on the bottom surface of the recess of the base;
A first member covering the light emitting element and disposed in a recess of the base;
A light diffusing member that covers the first member, is disposed in the recess of the base, and diffuses light from the light emitting element; And a second member containing a large amount of the light diffusing member in the same volume. A base having a recess having a bottom surface and a side surface;
A light emitting element placed on the bottom surface of the recess of the base;
A first member covering the light emitting element and disposed in a recess of the base;
A light diffusing member that covers the first member, is disposed in the recess of the base, and diffuses light from the light emitting element is contained, and the thickness is greater than the thickness near the side surface of the base. And a second member having a larger thickness in the vicinity of the upper portion of the light emitting element.   3. The light emitting device according to claim 1, wherein a thickness of the second member above the light emitting element is thicker than a thickness of the first member above the light emitting element.   The light emitting device according to claim 1, wherein the first member is filled up to a position lower than an upper end of the concave portion.   3. The light emitting device according to claim 1, wherein the concave portion has a step on a side surface, and the first member is disposed on a lower portion.   The light emitting device according to claim 1, wherein the first member and the second member are fixed without an interface.   The said 1st member contains the fluorescent material which absorbs the light from the said light emitting element, and discharge | releases the light of a wavelength different from the light from the said light emitting element, The Claim 1 or Claim characterized by the above-mentioned. 2. The light emitting device according to 2.   The light emitting device according to claim 1, wherein the first member is formed in a concave shape.   The light emitting device according to claim 1, wherein the second member is formed in a convex shape protruding from a concave portion of the base.   The light emitting device according to claim 1, wherein a third member is further provided on the second member. A base including a concave portion having a bottom surface and a side surface; a light emitting element placed on the bottom surface of the concave portion of the base; a first member covering the light emitting element; and a light diffusing member, A second member that covers the first member, and a method for manufacturing the light emitting device,
A first step of placing a light emitting element on the bottom surface of the base;
A second step of disposing a first member in the recess;
And a third step of disposing the second member on the first member so that the thickness near the upper side of the light emitting element is thicker than the thickness near the side surface of the base. A method for manufacturing a light emitting device.   The method of manufacturing a light emitting device according to claim 11, wherein the second step is arranged such that the first member is cured and has a concave shape.   The method of manufacturing a light emitting device according to claim 11, wherein in the third step, the second member is disposed before the first member is fully cured. The method of manufacturing a light emitting device according to claim 11, wherein the third step includes dropping a second member from above the light emitting element to form a convex shape protruding from the concave portion.

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