JP2007005733A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently take out light from a light-emitting device while realizing miniaturization. <P>SOLUTION: The light-emitting device 2 is a light-emitting element radiating light from its upper surface 20 to an optical component 3. The optical part 3 is connected with the light-emitting device 2, so that light from the light-emitting device 2 is made incident from an incident surface 30, and the light which is made incident from the incident surface 30 outgoes from an outgoing surface 31 to the atmosphere. The outgoing surface 31 is a nearly elliptically spherical surface whose focal points are endpoints A and B maximizing a distance therebetween at the periphery of the light-emitting area of the light-emitting device 2. At the outgoing surface 31, an angle θ2 is made to be not larger than double of a critical angle θc decided based on the ratio of the refractive index n1 of the optical component 3 to the refractive index n2 of the atmosphere, so that a maximum incident angle θimax is not larger than the critical angle θc. The light radiated from the upper surface 20 of the light-emitting device 2 is incident from the incident surface 30 of the optical component 3, passes through the inside of the optical component 3, and reaches the outgoing surface 31 with an incident angle θi. The incident angle θi is not larger than the critical angle θc, most of the light having reached the outgoing surface 31 outgoes to the atmosphere without being reflected entirely. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting device for emitting light.

  Conventionally, as this type of light emitting device, for example, there is a gallium nitride compound semiconductor light emitting element (light emitting device) as disclosed in Patent Document 1. As shown in FIG. 14, the conventional light emitting device 4 includes a sapphire substrate (optical component) 40 and a light emitting unit 41. The light emitting unit 41 is formed by stacking an n-type GaN layer (n-type semiconductor layer) 410 and a p-type GaN layer (p-type semiconductor layer) 411 and is joined to the sapphire substrate 40. Each of the n-type GaN layer 410 and the p-type GaN layer 411 is provided with an electrode 412. In such a conventional light emitting device 4, the light emitted from the light emitting unit 41 passes through the sapphire substrate 40 and is emitted to the outside atmosphere.

Non-Patent Document 1 describes that when a large hemisphere is used as an optical component, light can be extracted.
JP-A-6-291368 (pages 3 and 4 and FIG. 1) W. N. Carr, “PHOTOMETRIC FIGURES OF MERIT FOR SEMICONDUCTOR LUMINESCENT SOURCES OPERATING IN SPONTANEOUS MODE”, Infrared Physics, 1966, Vol. 6 pp. 1-19

  However, in the conventional light emitting device described above, since the refractive index of the optical component is larger than the refractive index of the atmosphere, the light from the light emitting unit repeatedly undergoes total reflection and multiple reflections at many portions of the interface between the optical component and the atmosphere. There is a problem that the light extraction efficiency is lowered. Here, a light-emitting device that directly emits light from the light-emitting unit to the atmosphere without an optical component is conceivable. However, since the refractive index of the light-emitting unit is also larger than the refractive index of the air, The problem that multiple reflection occurs due to repeated total reflection and the light extraction efficiency decreases cannot be solved. Further, even when an optical component such as Non-Patent Document 1 is used, it is unclear how large a hemisphere is necessary, and there is a problem that the size becomes large.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a light emitting device capable of extracting light from the light emitting portion with high efficiency while achieving downsizing. .

  The invention according to claim 1 includes a light emitting unit that emits light from one surface, an incident surface that is bonded to one surface of the light emitting unit and receives light from the light emitting unit, and the incident surface. An optical component having an exit surface from which incident light from the light emitting section exits, wherein the exit surface is located at a peripheral edge of the light emitting region of the light emitting section and has a maximum distance as a focal point; And an approximately ellipsoidal surface in which an angle formed by two straight lines connecting each of the above and a point on the exit surface is not more than twice a critical angle based on a refractive index ratio inside and outside the exit surface.

  With this configuration, it is possible to reduce the total reflection of the light from the light emitting unit with the minimum required size in the optical component, so that the light from the light emitting unit can be extracted with high efficiency while reducing the size. Can do.

  The invention according to claim 2 includes a light emitting portion that emits light from one surface, an incident surface that is joined to one surface of the light emitting portion and receives light from the light emitting portion, and the incident surface. An optical component having an exit surface from which incident light from the light emitting section exits, wherein the exit surface is located at a peripheral edge of the light emitting region of the light emitting section and has a maximum distance as a focal point; The major axis a is defined as a ≧ (n1 / n2) by the distance 2L between them, the refractive index n1 in the exit surface, the refractive index n2 outside the exit surface, and the critical angle θc based on the refractive index ratio inside and outside the exit surface. It is characterized by including a substantially ellipsoidal surface where xL and the minor axis b are b ≧ (n1 / n2) × L × cos θc.

  With this configuration, it is possible to reduce the total reflection of the light from the light emitting unit with the minimum required size in the optical component, so that the light from the light emitting unit can be extracted with high efficiency while reducing the size. Can do.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the light emitting section is composed of one or more light emitting elements, and each light emitting region of the one or more light emitting elements is planar. It is characterized by arranging. With this configuration, even when the light emitting unit is composed of one or more light emitting elements, light from the light emitting unit can be efficiently extracted.

  Invention of Claim 4 is invention in any one of Claims 1-3, Comprising: While providing the said light emission part in multiple connection, the said optical component corresponding to each of the said light emission part is said, A substantially elliptic spherical surface is provided so as to be connected. With this configuration, the size of the incident surface in the vertical direction can be reduced in the optical component.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, characterized in that the optical component has a minute uneven portion on the exit surface. In this configuration, since the Fresnel loss at the exit surface of the optical component can be reduced, the light from the light emitting unit can be extracted more efficiently.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, characterized in that the optical component has a recess for accommodating the light emitting part on the incident surface. In this configuration, the side surface of the light emitting unit can be covered with the optical component, so that light from the side surface of the light emitting unit can also be extracted efficiently.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, characterized in that the substantially elliptic spherical surface is provided by being approximated by a combination of a plurality of planes. With this configuration, the emission surface of the optical component can be easily formed.

  The invention according to an eighth aspect is the invention according to any one of the first to seventh aspects, wherein the optical component is inclined and extended outward from a peripheral edge of the incident surface in a direction perpendicular to the incident surface. It has the side which has. In this configuration, light in a direction substantially parallel to one surface of the light emitting unit can be totally reflected and converted into the vertical direction of the one surface to be extracted, so that the brightness in the vertical direction can be improved. it can.

  The invention according to claim 9 is the invention according to claim 8, wherein the side surface is inclined outward at an angle equal to or greater than the critical angle with respect to a perpendicular perpendicular to the incident surface. In this configuration, light in a direction substantially parallel to one surface of the light emitting unit can be totally reflected by the side surface of the optical component, so that light from the light emitting unit can be extracted more efficiently.

  The invention according to claim 10 is the invention according to claim 9, wherein the angle is 45 degrees or more. In this configuration, light in a direction substantially parallel to one surface of the light emitting unit can be further totally reflected by the side surface of the optical component, so that light from the light emitting unit can be extracted more efficiently.

  The invention according to claim 11 is the invention according to any one of claims 1 to 10, wherein the light reflected by the emission surface is on a portion of the incident surface where the optical component is not joined to the light emitting portion. It has a reflecting part that reflects. In this configuration, since the light reflected by the Fresnel at the exit surface of the optical component can be reflected by the reflecting portion and emitted from the exit surface, the light from the light emitting portion can be extracted more efficiently.

  The invention according to claim 12 is the invention according to any one of claims 1 to 11, wherein the light emitting part is a semiconductor, and the optical component is a growth substrate of the light emitting part. . With this configuration, it is possible to reduce the component that is totally reflected at the interface between the light emitting unit and the optical component, so that light can be extracted more efficiently.

  The invention according to claim 13 is the invention according to any one of claims 1 to 11, wherein the optical component is a semiconductor. In this configuration, when the light emitting unit is a semiconductor, it is possible to reduce the components that are totally reflected at the interface between the light emitting unit and the optical component, and thus it is possible to extract light more efficiently. Further, the light emitting portion and the optical component can be easily formed integrally.

  The invention according to claim 14 is the invention according to any one of claims 1 to 11, wherein the optical component is at least one of resin, glass, and sapphire glass. With this configuration, the optical component can be easily formed.

  The invention according to claim 15 is the invention according to claim 14, wherein the optical component is a resin and is formed by a nanoimprint method. With this configuration, the optical component can be formed with high accuracy.

  According to the present invention, light from the light emitting unit can be extracted with high efficiency while achieving downsizing.

(Embodiment 1)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view illustrating a configuration of the light emitting device according to the first embodiment. FIG. 2 is an external perspective view showing the configuration of the light emitting unit of the first embodiment.

  First, the basic configuration of the first embodiment will be described. The light-emitting device 1 of Embodiment 1 is provided with the light emission part 2 and the optical component 3, as shown in FIG.

  As shown in FIG. 2, the light emitting unit 2 is a light emitting element that is formed in a substantially rectangular shape and has a refractive index larger than that of the atmosphere. The n type semiconductor layer and the p type semiconductor layer are sequentially formed from the upper surface 20 side to the lower surface 21 side. (Not shown) are stacked. Each of the n-type semiconductor layer and the p-type semiconductor layer is provided with an electrode (not shown) on the lower surface 21 side. The light emitting unit 2 emits light from the upper surface 20 to the optical component 3 (see FIG. 1) by generating light from the interface between the n-type semiconductor layer and the p-type semiconductor layer. At the same time, the light emitting unit 2 also emits light from the side surfaces 22, 22, 23, and 23 to the outside which is the atmosphere. Here, it is the pair of end points A and B that are located at the periphery of the light emitting region of the light emitting unit 2 and have a maximum distance, and the distance connecting the end points A and B is 2L. In addition, the light emission part 2 is not limited to what is formed in a substantially rectangular shape, For example, you may form in a substantially square shape or a substantially circular shape.

As shown in FIG. 1, the optical component 3 is a substrate having transparency, and includes an entrance surface 30 and an exit surface 31, and is joined to the upper surface 20 of the light emitting unit 2 at the entrance surface 30. The optical component 3 is formed of a growth substrate material for the light emitting section 2 such as sapphire (Al ₂ O ₃ ), glass (SiO ₂ ), silicon carbide (SiC), or the like. In such an optical component 3, light from the light emitting unit 2 is incident from the incident surface 30, and light incident from the incident surface 30 is emitted from the emission surface 31 to the atmosphere.

  The exit surface 31 is a substantially elliptic spherical surface with the end points A and B of the light emitting unit 2 joined to the entrance surface 30 as focal points. When an angle formed by two straight lines AP and BP connecting each of the end points A and B and an arbitrary point P on the exit surface 31 is an angle θ1, the normal PN divides the angle θ1 into approximately equal halves. That is, the incident angle θi of the light emitted from the end points A and B of the light emitting unit 2 is one half of the angle θ1. Here, the maximum incident angle θimax in which the magnitude of the incident angle θi is the maximum is a case where light from the end points A and B of the light emitting unit 2 reaches the point Q. The exit surface 31 has an angle θ2 formed by two straight lines AQ and BQ connecting each of the end points A and B and the point Q to be not more than twice the critical angle θc. The critical angle θc is an angle determined based on the ratio of the refractive index n1 of the optical component 3 (inside the emission surface 31) and the refractive index n2 of the atmosphere (outside the emission surface 31), and θc = arcsin (n2 / n1). ). The refractive index n1 of the optical component 3 is 1.768 in the case of sapphire and 1.47 to 1.8 in the case of glass. On the other hand, the refractive index n2 of the atmosphere is 1. From the above, since the maximum incident angle θimax is one half of the angle θ2, the maximum incident angle θimax can be made equal to or less than the critical angle θc. Therefore, the incident angle of all the light radiated from the upper surface 20 of the light emitting unit 2 to the optical component 3 can be made equal to or less than the critical angle θc.

In addition, on the exit surface 31, the minor axis b is b ≧ L / tan θc = (n1 / n2) × L due to the distance 2L between the end points A and B (see FIG. 2), the refractive indexes n1 and n2, and the critical angle θc. X cos θc. Further, since the sum of the distances between the point Q on the emission surface 31 and the two end points A and B is AQ + QB = 2AQ = 2a, the major axis a is a = (L ² + b ² ) ^1/2 ≧ L × ( 1 + 1 / tan ² θc) ^1/2 = (n1 / n2) × L. From the above, the emission surface 31 is a substantially elliptical spherical surface having the major axis a and the minor axis b. Further, since the minor axis b is equal to or less than the major axis a, the optical component 3 can reduce the size of the incident surface 30 in the vertical direction.

  Next, an example of a manufacturing method in the case where the optical component 3 of Embodiment 1 is the inorganic insulator will be described. First, the light emitting unit 2 is laminated on the sapphire substrate. Subsequently, the sapphire substrate is formed in an approximately elliptical sphere as the optical component 3.

  Next, an optical path of light emitted from the light emitting unit 2 in the light emitting device 1 of Embodiment 1 will be described. First, the light emitted from the upper surface 20 of the light emitting unit 2 enters the optical component 3 from the incident surface 30. Subsequently, the light incident on the optical component 3 passes through the optical component 3 and reaches the emission surface 31 at an incident angle θi. Since the incident angle θi is equal to or smaller than the critical angle θc, most of the light reaching the emission surface 31 is emitted to the atmosphere without being totally reflected. As described above, total reflection and Fresnel loss can be reduced with respect to light from the upper surface 20 of the light emitting unit 2.

  As described above, according to the first embodiment, in the optical component 3, it is possible to reduce the total reflection of the light from the light emitting unit 2 with the minimum necessary size. Can be extracted with high efficiency. Further, the light emitting portion 2 is a semiconductor layer, and the optical component 3 is a transparent growth substrate (however, this is not the case when the refractive index difference between the transparent growth substrate of the optical component 3 and the semiconductor layer of the light emitting portion 2 is small). Therefore, the total reflection component at the interface between the light emitting unit 2 and the optical component 3 can be reduced, and light can be extracted more efficiently.

  As a modification of the first embodiment, an angle at which the transmittance of the light emitted from the emission surface of the optical component is 80 to 90% at the time of vertical incidence (θi = 0) is set as a pseudo-critical angle, and the critical angle is substituted. It may be used. If it does in this way, the light from a light emission part can be taken out still more efficiently.

  Further, the exit surface is not limited to a substantially elliptical spherical surface, and may be a substantially spherical surface having a major axis and a minor axis that are substantially equal. Even if it does in this way, the effect similar to Embodiment 1 can be acquired.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a cross-sectional view illustrating a configuration of the light emitting device according to the second embodiment. FIG. 4 is an external perspective view showing the configuration of the light emitting unit of the second embodiment.

  As shown in FIG. 3, the light emitting device 1a of the second embodiment includes the optical component 3 in the same manner as the light emitting device 1 of the first embodiment (see FIG. 1). There are no features described below.

  The light emitting device 1a includes a light emitting unit 2a as shown in FIG. 4 instead of the light emitting unit 2 of the first embodiment. The light emitting unit 2a includes a plurality of (for example, six) light emitting elements 24, 25, 26,. The plurality of light emitting elements 24, 25, 26,... Are separated from each other by a predetermined distance, and the respective light emitting areas are arranged in a plane. Here, it is the end point C of the light emitting element 24 and the end point D of the light emitting element 25 that has the maximum distance in the periphery of the light emitting region of the plurality of light emitting elements 24, 25, 26. The distance connecting the end points C and D is 2L. In addition, the light emission part 2a is the same as that of the light emission part 2 (refer FIG. 2) of Embodiment 1 in points other than the above.

  As shown in FIG. 3, the exit surface 31 of the optical component 3 of Embodiment 2 is a substantially elliptical spherical surface with the end points C and D as focal points. The optical component 3 of the second embodiment is the same as the optical component of the first embodiment (see FIG. 1) except for the points described above.

  As described above, even when the light emitting unit 2a includes the plurality of light emitting elements 24, 25, 26,... As in the second embodiment, the light from the light emitting unit 2a can be efficiently extracted.

(Embodiment 3)
Embodiment 3 of the present invention will be described with reference to FIG. FIG. 5A is a cross-sectional view showing the overall configuration of the light emitting device of the third embodiment. FIG. 5B is a cross-sectional view illustrating a main configuration of the light emitting device according to the third embodiment.

  As shown in FIG. 5A, the light emitting device 1b of Embodiment 3 includes a plurality of light emitting units 2b... Connected together, and a plurality of optical components 3a corresponding to each of the light emitting units 2b. .. are provided so that substantially elliptical spherical surfaces are connected.

  Each light emitting section 2b is the same as the light emitting section 2 of Embodiment 1 (see FIG. 1), as shown in FIG. 5B. Here, it is the pair of end points E and F that have the maximum distance in the periphery of the light emitting region of the light emitting unit 2b.

  On the other hand, each optical component 3a is the same as the optical component 3 of Embodiment 1 (see FIG. 1). The exit surface 31a of each optical component 3a is a substantially elliptical spherical surface with the end points E and F of the light emitting portion 2b joined to the entrance surface 30a as a focal point.

  As described above, according to the third embodiment, the same effect as that of the first embodiment can be obtained, and the optical component 3a is configured to be incident on each optical component 3a because it is configured as a substantially elliptical spherical surface with the end point of each light emitting unit 2b as a focal point. The size of the surface 30a in the vertical direction (the vertical direction in FIG. 5A) can be reduced. Further, even if the thickness of each optical component 3a before processing is thin in the direction perpendicular to the incident surface 30a, it can be processed. Furthermore, since a large shape process is not performed, even when each optical component 3a is a semiconductor or sapphire, it can be processed easily.

(Embodiment 4)
Embodiment 4 of the present invention will be described with reference to FIG. FIG. 6A is a cross-sectional view showing the configuration of the light emitting device of the fourth embodiment.

  As shown in FIG. 6A, the light emitting device 1c according to the fourth embodiment includes the light emitting unit 2 in the same manner as the light emitting device 1 according to the first embodiment (see FIG. 1), but the light emitting device according to the first embodiment. There are the following features that are not included in 1.

  The light emitting device 1c includes an optical component 3b as shown in FIG. 6A in place of the optical component 3 of the first embodiment. The emission surface 31b of the optical component 3b has a plurality of minute irregularities 310... On a substantially elliptical spherical surface (dotted line in FIG. 6A), and is less than about one quarter of the wavelength of light emitted from the light emitting unit 2. It is what has at intervals. The optical component 3b is the same as the optical component 3 of Embodiment 1 (see FIG. 1) except for the points described above.

  As described above, according to the fourth embodiment, the same effect as that of the first embodiment can be obtained, and the Fresnel loss at the emission surface 31b of the optical component 3b can be reduced. Can be taken out well.

  As a modification of the fourth embodiment, as shown in FIG. 6B, a plurality of light emitting units 2b... Are connected and a plurality of optical components 3c corresponding to each of the light emitting units 2b. In the light emitting device 1d provided with the emission surfaces 31c connected to each other, the emission surfaces 31c of the optical components 3c have a plurality of minute uneven portions 310a on a substantially elliptic spherical surface (dotted line in FIG. 6B). May be provided at intervals of about one quarter or less of the wavelength of the light emitted from the light emitting section 2b. Even if it is such a structure, the effect similar to Embodiment 4 can be acquired.

(Embodiment 5)
Embodiment 5 of the present invention will be described.

  The light emitting device of Embodiment 5 has the same configuration as the light emitting device 1c of Embodiment 4 (see FIG. 6A). The optical component of Embodiment 5 is formed by a nanoimprint method using a resin such as PMMA or methacrylic resin. The nanoimprint method is a method of transferring the shape of a mold to a resin by pressing a mold (mold) having nano-level micro unevenness onto the resin. In the fifth embodiment, the mold (not shown) has a contact surface with the resin that is a substantially elliptical spherical surface on which a plurality of minute irregularities are formed.

  Next, a method for forming the optical component of Embodiment 5 by a thermal nanoimprint method will be described. First, a resin and a mold (not shown) are heated above the glass transition temperature of the resin to soften the resin. Subsequently, the mold is brought into contact with the resin and pressed at a high pressure for a certain time. Finally, the resin and mold are cooled below the glass transition temperature, and after the resin has hardened, the mold is detached from the resin. As described above, it is possible to form an optical component having a minute uneven portion on the exit surface. The optical component is not limited to being formed by a thermal nanoimprint method, and may be formed by a UV-nanoimprint method or a room temperature nanoimprint method.

  As described above, according to the fifth embodiment, the same effect as that of the fourth embodiment can be obtained, and the optical component can be formed with high accuracy by the nanoimprint method.

  In addition, as a modification of Embodiment 5, it is not limited to the shape of the optical component of Embodiment 5, but may be the shape of the optical component in other embodiments. Even in such a shape of the optical component, the optical component can be formed with high accuracy as in the fifth embodiment.

(Embodiment 6)
Embodiment 6 of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view illustrating a configuration of the light emitting device according to the sixth embodiment.

  As shown in FIG. 7, the light emitting device 1e of the sixth embodiment includes the light emitting unit 2 in the same manner as the light emitting device 1 of the first embodiment (see FIG. 1). There are no features described below.

  The light emitting device 1e includes an optical component 3d as shown in FIG. 7 instead of the optical component 3 of the first embodiment. In the optical component 3d, the vertical length of the incident surface 30d is longer than the optical component 3 of Embodiment 1 (see FIG. 1) by the thickness d of the light emitting unit 2. The optical component 3d has a concave portion 300 having the same depth as the thickness d of the light emitting portion 2 near the center of the incident surface 30d. The light emitting unit 2 is accommodated in the recess 300. The optical component 3d is the same as the optical component 3 of Embodiment 1 (see FIG. 1) except for the points described above.

  Next, an optical path of light emitted from the light emitting unit 2 in the light emitting device 1e of Embodiment 6 will be described. The light emitted from the upper surface 20 of the light emitting unit 2 has the same optical path as in the first embodiment. Further, the light emitted from the side surfaces 22, 22, and 23 of the light emitting unit 2 also passes through the optical component 3d and is emitted from the emission surface 31d to the atmosphere. From the above, total reflection and Fresnel loss can be reduced even for light from the side surfaces 22, 22, and 23 of the light emitting unit 2.

  As described above, according to the sixth embodiment, the same effects as those of the first embodiment can be obtained, and the side surfaces 22, 22, and 23 of the light emitting unit 2 can be covered with the optical component 3, and thus the side surface 22 of the light emitting unit 2. , 22 and 23 can also be extracted efficiently.

(Embodiment 7)
Embodiment 7 of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view illustrating a configuration of the light emitting device according to the seventh embodiment.

  As shown in FIG. 8, the light emitting device 1 f of the seventh embodiment includes the light emitting unit 2 in the same manner as the light emitting device 1 of the first embodiment (see FIG. 1). There are no features described below.

  The light-emitting device 1f includes an optical component 3e as shown in FIG. 8 instead of the optical component 3 of the first embodiment. The exit surface 31e of the optical component 3e is provided by approximating a substantially elliptic spherical surface to a polygon by a combination of a plurality of planes 311. The optical component 3e is the same as the optical component 3 according to the first embodiment (see FIG. 1) except for the points described above.

  As described above, according to the seventh embodiment, the same effects as those of the first embodiment can be obtained, and the emission surface 31e of the optical component 3e can be easily formed.

(Embodiment 8)
Embodiment 8 of the present invention will be described with reference to FIG. FIG. 9A is a cross-sectional view illustrating a configuration of the light emitting device of the eighth embodiment.

  As shown in FIG. 9A, the light emitting device 1g according to the eighth embodiment includes the light emitting unit 2 in the same manner as the light emitting device 1 according to the first embodiment (see FIG. 1), but the light emitting device according to the first embodiment. There are the following features that are not included in 1.

  The light emitting device 1g includes an optical component 3f as shown in FIG. 9A instead of the optical component 3 of the first embodiment. The optical component 3f has side surfaces 32 and 32 extending from the peripheral edges 301 and 301 of the incident surface 30f so as to incline outward (in the left-right direction in FIG. 9A) in the vertical direction of the incident surface 30f. . Further, the emission surface 31 f of the optical component 3 f includes parallel surfaces 313 and 313 extending from the side surfaces 32 and 32 around the substantially elliptic spherical surface 312. The parallel surfaces 313 and 313 are parallel to the incident surface 30f. The optical component 3f according to the eighth embodiment is the same as the optical component 3 according to the first embodiment (see FIG. 1) except for the points described above.

  Next, an optical path of light emitted from the light emitting unit 2 in the light emitting device 1g of the eighth embodiment will be described. First, the light emitted from the upper surface 20 of the light emitting unit 2 enters the optical component 3 from the incident surface 30f. Subsequently, the light incident on the optical component 3 passes through the optical component 3 and reaches the exit surface 31 f or the side surfaces 32 and 32. The light reaching the side surfaces 32 and 32 is totally reflected, and the direction is changed from the substantially parallel direction (left-right direction in FIG. 9A) of the incident surface 30f to the substantially vertical direction (up-down direction in FIG. 9A). The The light whose direction has been changed is emitted from the parallel surfaces 313 and 313 of the emission surface 31f to the atmosphere. From the above, light in a direction substantially parallel to the upper surface 20 of the light emitting unit 2 can be totally reflected by the side surfaces 32 and 32 to change the direction in a substantially vertical direction of the upper surface 20. In addition, the light which reached | attained the output surface 31f is radiate | emitted to air | atmosphere similarly to Embodiment 1. FIG.

  As described above, according to the eighth embodiment, the same effect as that of the first embodiment can be obtained, and light in a direction substantially parallel to the upper surface 20 of the light emitting unit 2 (the left-right direction in FIG. 9A) is totally reflected. Therefore, the brightness in the vertical direction can be improved because the upper surface 20 can be converted into a substantially vertical direction (the vertical direction in FIG. 9A) and taken out.

  As a modification of the eighth embodiment, a light emitting device 1h including an optical component 3g as shown in FIG. 9B may be used. Even if it does in this way, the effect similar to Embodiment 8 can be acquired.

(Embodiment 9)
A ninth embodiment of the present invention will be described with reference to FIG. FIG. 10 is a cross-sectional view illustrating a configuration of the light emitting device according to the ninth embodiment.

  As shown in FIG. 10, the light emitting device 1 i of the ninth embodiment includes the light emitting unit 2 in the same manner as the light emitting device 1 g of the eighth embodiment (see FIG. 9A), but the light emitting device of the eighth embodiment. There are the following characteristic parts which are not in 1g.

  The light emitting device 1i includes an optical component 3h as shown in FIG. 10 instead of the optical component 3f of the eighth embodiment. The side surface 32a of the optical component 3h is inclined outward at an angle θ3 that is greater than or equal to the critical angle θc with respect to a perpendicular (dotted line in FIG. 10) perpendicular to the incident surface 30h. The angle θ3 is preferably 45 degrees or more. The angle θ4 formed by the optical path of the light emitted from the end point A of the light emitting unit 2 and the side surface 32a is equal to or greater than (π / 2−θc). The optical component 3h is the same as the optical component 3f of the eighth embodiment (see FIG. 9A) except for the points described above.

  As described above, according to the ninth embodiment, the light substantially parallel to the upper surface 20 of the light emitting unit 2 can be further totally reflected by the side surface 32a of the optical component 3h, so that the light from the light emitting unit 2 can be extracted more efficiently. be able to.

(Embodiment 10)
A tenth embodiment of the present invention will be described with reference to FIG. FIG. 11A is a cross-sectional view showing the configuration of the light emitting device of the tenth embodiment.

  As shown in FIG. 11A, the light emitting device 1j according to the tenth embodiment includes the light emitting unit 2 in the same manner as the light emitting device 1g according to the eighth embodiment (see FIG. 9A). The light emitting device 1g has the following characteristic portions that are not included in the light emitting device 1g.

  The light emitting device 1j includes an optical component 3i as shown in FIG. 11A instead of the optical component 3f of the eighth embodiment. The side surface 32a of the optical component 3i is inclined outward at an angle θ3 having a size of 45 degrees or more with respect to a perpendicular (dotted line in FIG. 10) perpendicular to the incident surface 30i. Further, the emission surface 31i of the optical component 3i includes flat surfaces 314 and 314 extending from the side surfaces 32b and 32b around the substantially elliptical spherical surface 312. The planes 314 and 314 are provided in the tangential direction of the substantially elliptic spherical surface 312 at the boundary point M with the substantially elliptic spherical surface 312. The optical component 3i is the same as the optical component 3f of the eighth embodiment (see FIG. 9A) except for the points described above.

  As described above, according to the tenth embodiment, light substantially parallel to the upper surface 20 of the light emitting unit 2 can be further totally reflected by the side surface 32b of the optical component 3i. In addition, the planes 314 and 314 can reduce the downward total reflection component occurring on the parallel surfaces 313 and 313 (see FIG. 9A) of the eighth embodiment. , The upper luminous flux can be improved.

  As a modification of the tenth embodiment, the angle θ5 may be controlled instead of controlling the angle θ3. Even if it does in this way, the effect similar to Embodiment 10 can be acquired.

  Further, as another modification of the embodiment 10, a light emitting device 1m as shown in FIG. The optical component 3l of the light emitting device 1m has a concave portion 300 having the same depth as the thickness d of the light emitting unit 2 near the center of the incident surface 30l. Even if it is such a structure, the effect similar to Embodiment 10 can be acquired.

(Embodiment 11)
An eleventh embodiment of the present invention will be described with reference to FIG. FIG. 12 is a cross-sectional view illustrating a configuration of the light emitting device according to the eleventh embodiment.

  As shown in FIG. 12, the light emitting device 1k according to the eleventh embodiment includes the light emitting unit 2 in the same manner as the light emitting device 1 according to the first embodiment (see FIG. 1). There are no features described below.

  The light emitting device 1k includes an optical component 31j as shown in FIG. 12 instead of the optical component 3 of the first embodiment. The optical component 3j has reflecting portions 33 and 33 in portions 303 and 303 that are not joined to the light emitting portion 2 in the incident surface 30j. The reflecting portion 33 is made of, for example, gold by vapor deposition or the like, has a high reflectivity, and reflects light that has been Fresnel-reflected by the emission surface 31j. The optical component 3j according to the eleventh embodiment is the same as the optical component 3 according to the first embodiment (see FIG. 1) except for the points described above.

  As described above, according to the eleventh embodiment, the same effect as in the first embodiment can be obtained, and the light reflected by the Fresnel at the emission surface 31j of the optical component 3j is reflected by the reflecting portion 33 and emitted from the emission surface 31j. Therefore, the light from the light emitting unit 2 can be extracted more efficiently.

Embodiment 12
A twelfth embodiment of the present invention will be described with reference to FIG. FIG. 13 is a cross-sectional view illustrating a configuration of the light emitting device according to the twelfth embodiment.

  As shown in FIG. 13, the light emitting device 11 according to the twelfth embodiment includes the light emitting unit 2 in the same manner as the light emitting device 1 according to the first embodiment (see FIG. 1). There are no features described below.

  The light emitting device 11 includes an optical component 3k as shown in FIG. 13 instead of the optical component 3 of the first embodiment. The incident surface 30k of the optical component 3k has the same size as the light emitting unit 2. Further, the emission surface 31k of the optical component 3k includes a substantially elliptic spherical surface 315 and a flat surface 316. In the optical component 3k, the incident angle θi of light emitted from the end points A and B of the light emitting unit 2 to the emission surface 31k from the one formed in a substantially rectangular parallelepiped shape (see the dotted line in FIG. 13) exceeds the critical angle θc. Only the portion is shaved so that the surface becomes a substantially elliptical spherical surface 315. On the other hand, a portion where the incident angle θi is equal to or smaller than the critical angle θc is a plane 316. As described above, the incident angle θi is equal to the critical angle θc at the boundary between the substantially elliptic spherical surface 315 and the plane 316. The optical component 3k is the same as the optical component 3 according to the first embodiment (see FIG. 1) except for the points described above.

  As described above, according to the twelfth embodiment, the same effects as those of the first embodiment can be obtained, and since the processing of the optical component 3k can be reduced, it can be easily formed. Moreover, since the width of the optical component 3k in the left-right direction can be made equal to that of the light emitting unit 2, the size can be further reduced.

(Embodiment 13)
A thirteenth embodiment of the present invention will be described.

  As shown in FIG. 1, the light emitting device 1 according to the thirteenth embodiment includes the light emitting unit 2 and the optical component 3 in the same manner as the light emitting device according to the first embodiment, but is not included in the light emitting device according to the first embodiment. There are the following features.

  In the light emitting device 1 according to the thirteenth embodiment, the optical component 3 is formed of the same semiconductor as the light emitting unit 2, such as GaN, GaAs, GaP, or SiC. The refractive index n1 of the optical component 3 is 2.5 in the case of GaN, 3.3 to 3.8 in the case of GaAs, 3.31 in the case of GaP, and 2.7 to 4.1 in the case of SiC. . The optical component 3 of the thirteenth embodiment is the same as the optical component of the first embodiment except for the points described above.

  Next, an example of a method for producing the optical component 3 according to Embodiment 13 will be described. First, a semiconductor layer corresponding to the optical component 3 and a semiconductor layer corresponding to the light emitting unit 2 are sequentially stacked on the sapphire substrate. Subsequently, the semiconductor layer is peeled from the sapphire substrate. Finally, a semiconductor layer corresponding to the optical component 3 is processed to form a substantially elliptical emission surface 31.

  As described above, according to the thirteenth embodiment, since both the light emitting unit 2 and the optical component 3 are semiconductor layers, a component that is totally reflected at the interface between the light emitting unit 2 and the optical component 3 can be reduced, and more efficiently. Light can be extracted. Further, the light emitting unit 2 and the optical component 3 can be easily formed integrally.

(Embodiment 14)
A fourteenth embodiment of the present invention will be described.

  As shown in FIG. 1, the light-emitting device 1 according to the fourteenth embodiment includes the light-emitting unit 2 and the optical component 3 in the same manner as the light-emitting device according to the first embodiment. There are the following features.

  In the light emitting device 1 according to the fourteenth embodiment, the optical component 3 includes a base (not shown) and a peripheral part (not shown) provided around the base. The base is, for example, a growth substrate of the light emitting unit 2 such as sapphire or glass, or a semiconductor such as GaN, GaAs, GaP, or SiC. On the other hand, the peripheral portion is, for example, resin, glass or the like, and the emission surface 31 of the optical component 3 is made into a substantially elliptic spherical surface. The optical component 3 according to the fourteenth embodiment is the same as the optical component according to the first embodiment except for the points described above.

  Next, an example of a method for producing the optical component 3 of Embodiment 14 will be described. First, the light emitting unit 2 is stacked on the sapphire or semiconductor base (not shown). Subsequently, a resin is provided on the base as a peripheral portion (not shown), and a substantially elliptical light emitting surface 31 is formed from the resin.

  As described above, according to the fourteenth embodiment, even in the case where the optical component 3 cannot be processed on a base (not shown) such as a growth substrate or a semiconductor, a peripheral portion (not shown) such as resin or glass. ), A light exit surface having a substantially elliptical spherical shape can be formed, and light can be extracted efficiently as in the first embodiment.

(Embodiment 15)
Embodiment 15 of the present invention will be described.

  As shown in FIG. 1, the light emitting device 1 according to the fifteenth embodiment includes the light emitting unit 2 and the optical component 3 in the same manner as the light emitting device according to the first embodiment, but is not included in the light emitting device according to the first embodiment. There are the following features.

  In the light emitting device 1 of the fifteenth embodiment, the light emitting section 2 is a semiconductor laminated on a growth substrate, and the optical component 3 is a high refractive index material (refractive index n = 1.5) such as resin, glass, or sapphire glass. ˜1.8) and is provided after the light emitting portion 2 is formed. In addition, the optical component 3 of Embodiment 15 is not limited to the said material, You may select suitably according to a use. The optical component 3 according to the fifteenth embodiment is the same as the optical component according to the first embodiment except for the points described above.

  As described above, according to the fifteenth embodiment, the optical component 3 can be easily formed.

  As a modification of any of Embodiments 1 to 4, 6 to 12, 14, and 15, the light emitting unit may be an organic EL. Even if it is such a structure, the effect similar to any of Embodiment 1-4, 6-12, 14, 15 can be acquired.

It is sectional drawing which shows the structure of the light-emitting device of Embodiment 1, 13-15 by this invention. It is an external appearance perspective view which shows the structure of a light emission part same as the above. It is sectional drawing which shows the structure of the light-emitting device of Embodiment 2 by this invention. It is an external appearance perspective view which shows the structure of a light emission part same as the above. It is the light-emitting device of Embodiment 3 by this invention, Comprising: (a) is sectional drawing which shows the whole structure, (b) is sectional drawing which shows a principal part structure. It is a light-emitting device of Embodiment 4 by this invention, Comprising: (a) is sectional drawing which shows a structure of an example, (b) is sectional drawing which shows the structure of another example. It is sectional drawing which shows the structure of the light-emitting device of Embodiment 6 by this invention. It is sectional drawing which shows the structure of the light-emitting device of Embodiment 7 by this invention. It is a light-emitting device of Embodiment 8 by this invention, Comprising: (a) is sectional drawing which shows a structure of an example, (b) is sectional drawing which shows the structure of another example. It is sectional drawing which shows the structure of the light-emitting device of Embodiment 9 by this invention. It is a light-emitting device of Embodiment 10 by this invention, Comprising: (a) is sectional drawing which shows a structure of an example, (b) is sectional drawing which shows another example. It is sectional drawing which shows the structure of the light-emitting device of Embodiment 11 by this invention. It is sectional drawing which shows the structure of the light-emitting device of Embodiment 12 by this invention. It is sectional drawing which shows the structure of the conventional light-emitting device.

Explanation of symbols

2 Light emitting unit 20 Upper surface 3 Optical component 30 Incident surface 31 Outgoing surfaces A and B End point θ2 Angle θi Incident angle θimax Maximum incident angle

Claims (15)

With a light emitting part that emits light from one surface,
An optical component having an incident surface that is bonded to one surface of the light emitting unit and receives light from the light emitting unit, and an output surface from which light from the light emitting unit incident from the incident surface is emitted,
The exit surface is located at the periphery of the light emitting region of the light emitting section and has a pair of end points where the distance is the maximum, and an angle formed by two straight lines connecting each of the focal points and the point on the exit surface, A light emitting device comprising: a substantially elliptical spherical surface having a critical angle that is not more than twice the critical angle based on the refractive index ratio inside and outside the emitting surface. With a light emitting part that emits light from one surface,
An optical component having an incident surface that is bonded to one surface of the light emitting unit and receives light from the light emitting unit, and an output surface from which light from the light emitting unit incident from the incident surface is emitted,
The exit surface is located at the periphery of the light emitting region of the light emitting section and has a pair of end points with the maximum distance as a focal point. The distance 2L between the focal points, the refractive index n1 within the exit surface, and the refraction outside the exit surface. The major axis a is set as a ≧ (n1 / n2) × L and the minor axis b is set as b ≧ (n1 / n2) × L × cos θc based on the refractive index n2 and the critical angle θc based on the refractive index ratio inside and outside the exit surface. A light emitting device characterized by including a substantially elliptic spherical surface.   The light-emitting device according to claim 1, wherein the light-emitting portion includes one or more light-emitting elements, and each light-emitting region of the one or more light-emitting elements is arranged in a planar shape. A plurality of the light emitting units are connected and provided,
The light-emitting device according to claim 1, wherein the optical component corresponding to each of the light-emitting portions is provided so that the substantially elliptic spherical surfaces are connected.   The light-emitting device according to claim 1, wherein the optical component has a minute uneven portion on the emission surface.   The light-emitting device according to claim 1, wherein the optical component has a concave portion that accommodates the light-emitting portion on the incident surface.   The light emitting device according to claim 1, wherein the substantially elliptic spherical surface is provided by being approximated by a combination of a plurality of planes.   The light-emitting device according to claim 1, wherein the optical component has a side surface that is inclined and extended outward from a peripheral edge of the incident surface in a direction perpendicular to the incident surface.   9. The light emitting device according to claim 8, wherein the side surface is inclined outward at an angle equal to or greater than the critical angle with respect to a perpendicular perpendicular to the incident surface.   The light emitting device according to claim 9, wherein the angle is 45 degrees or more.   The light-emitting device according to claim 1, wherein the optical component has a reflection part that reflects light reflected by the emission surface at a part of the incident surface that is not bonded to the light-emitting part. . The light emitting unit is a semiconductor;
The light emitting device according to claim 1, wherein the optical component is a growth substrate of the light emitting unit.   The light-emitting device according to claim 1, wherein the optical component is a semiconductor.   The light-emitting device according to claim 1, wherein the optical component is at least one of resin, glass, and sapphire glass.   The light-emitting device according to claim 14, wherein the optical component is a resin and is formed by a nanoimprint method.

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