JP2014022489A - Semiconductor light-emitting device with optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device which can distribute light in a wide angle range while suppressing variations of illumination distribution on an irradiated surface by largely refracting a light flux in the vicinity of an optical axis of a semiconductor light-emitting element, in the light-emitting device including a light source with the semiconductor light-emitting element.SOLUTION: A light-emitting device includes: a light source having a semiconductor light-emitting element and a hemispherical transparent sealed body for sealing the semiconductor light-emitting element; and an optical member for controlling light distribution characteristics of light emitted by the semiconductor light-emitting element. The shape of the optical member includes: a concave inner contour for housing the hemispherical transparent sealed body, a bottom surface contour connected to the periphery of the inner contour, and an outer contour connected to the bottom surface contour. When a vertical axis with respect to a light-emitting surface in an emission center of the semiconductor light-emitting element is determined as an optical axis, an interval between a surface of the hemispherical transparent sealed body in an optical axis direction and the concave inner contour becomes the longest and an area forming an angle equal to or more than 45° from the emission center to the optical axis has a part with the shortest interval.

Description

  The present invention relates to a light emitting device including an optical member that distributes light at a wide light distribution angle while suppressing variation in illuminance distribution on an irradiation surface.

  In recent years, applications of semiconductor light-emitting devices (hereinafter also referred to as LED packages) using light-emitting diodes (LEDs) are expanding. Specifically, for example, it is used in general indoor lighting fixtures, spotlights such as interior lights, backlights used in flat-screen TVs and information terminal devices, advertising panels and sign panels, automobile tail lamps, street lights, traffic lights, etc. ing.

  Conventionally, as an LED package, for example, an LED package 300 that is a planar package as shown in FIG. 10 has been widely known. Such an LED package 300 has a concave light-emitting body accommodating member 302 whose upper surface that accommodates the LED element 301 is open. And the recessed part which accommodates LED element 301 is sealed by the transparent sealing body 303 which forms the outline where the surface is a plane or the center part was depressed a little. As described above, by mounting the LED element in a package, mounting on the circuit board is facilitated.

  In the LED package 300 as shown in FIG. 10, the light emitted from the LED element 301 is reflected or refracted inside and at the interface of the transparent sealing body 303 as indicated by the arrow in FIG. 10. The optical path is bent by this, so that the irradiation range of the light emitted to the outside is widened. As shown in FIG. 11, such a planar package has a Lambertian pattern in which the luminance of the light emitting surface is substantially constant in all directions with the optical axis perpendicular to the light emitting surface passing through the center of the LED element 301 as the center. Indicates light distribution. In Lambert light distribution, the luminous intensity distribution is proportional to cos α, where α is the angle formed with the optical axis. However, in such a flat type package, there is a problem that the amount of light is greatly lost because there is light that is diffusely reflected by repeated total reflection inside the transparent sealing body.

  As an LED package with high light extraction efficiency that solves the problem of light quantity loss of such a planar package, the LED element 1a mounted on the submount substrate 1b as shown in FIG. An LED package 1 formed by sealing with a sealing body 1c is known.

  The LED package 1 provided with the hemispherical transparent sealing body 1c radiates light emitted from the LED element 1a into the transparent sealing body 1c. The emitted light is incident on the hemispherical interface of the transparent encapsulant 1c at a substantially right angle, and is emitted from the transparent encapsulant 1c without being totally reflected. According to such an LED package 1, the loss of light amount that occurs in a planar package is suppressed.

  The LED package provided with the hemispherical transparent sealing body has the following problems although the loss of the light amount is suppressed as described above. As shown by the arrows in FIG. 12, the light emitted from the hemispherical transparent encapsulant 1c is emitted from the transparent encapsulant 1c to the outside which is an air layer. Due to the effect, the light tends to be condensed in the optical axis direction as compared with the flat type package. Specifically, as shown in FIG. 11, the LED package including the planar package emits light so as to have a Lambertian light distribution that completely diffuses. On the other hand, as shown in FIG. 13, the LED package having a hemispherical transparent encapsulant collapses the Lambert light distribution and condenses in the optical axis direction, and the amount of light near the optical axis increases relatively. The amount of ambient light is relatively small. As a result, there has been a problem that the variation in illuminance on the irradiated surface increases.

  For example, Patent Document 1 below discloses a wide angular range by arranging a wide-angle radiation angle lens 202 in combination with an LED device having a hemispherical transparent sealing body 198 as shown in FIG. Disclosed is a light-emitting device 188 that realizes the light distribution.

  Further, for example, as shown in FIG. 15, the following Patent Document 2 includes an LED element 201 disposed on a substrate having a light incident surface 202 a and a light emitting surface 202 b having a predetermined shape, and a light emitting surface 202 b. By covering with a lens 202 having a recess 202c at the center of the optical axis, the light emitted from the LED element 201 is refracted by the light incident surface 202a and the light emitting surface 202b of the lens 202, thereby distributing light in a wide angular range. It is proposed to be realized. Patent Document 2 is a technique related to an LED device that controls light distribution from the LED element itself.

Special table 2010-519757 gazette JP 2009-44016 A

  When a lens for largely refracting light is arranged in an LED package having a conventional hemispherical transparent sealing body as disclosed in Patent Document 1, as shown in FIG. In order to increase the incident angle when the light beam is incident on the surface of the concave portion, it is necessary to form an inner wall that rises close to the vertical. In order to form the rising inner wall surface, it is necessary to secure a sufficient lens height. In such a case, there is a problem that it is difficult to install in an area where there is little space in the height direction. That is, in the case of the light emitting device having the lens as shown in FIG. 14, a sufficient space in the height direction is necessary in the mounting region.

  The present invention provides a semiconductor light emitting device having a hemispherical transparent encapsulant, which refracts a light beam in the vicinity of the optical axis of the semiconductor light emitting element so as to suppress a variation in illuminance distribution on the irradiated surface, and in a wide angle range. An object of the present invention is to provide a light-emitting device including an optical member that can distribute light and has a reduced thickness.

One aspect of the present invention is a light-emitting device including a semiconductor light-emitting element, a hemispherical transparent sealing body that seals the semiconductor light-emitting element, and an optical device for controlling light distribution characteristics of light emitted from the semiconductor light-emitting element A layer having a smaller refractive index than the transparent sealing body and the optical member, and the shape of the optical member accommodates the transparent sealing body. And an outer contour that defines the contour of the light emitting surface, and the optical axis is the vertical axis with respect to the light emitting surface at the light emitting center of the semiconductor light emitting element, and the optical axis is an arbitrary section cut by a plane including the optical axis In the vertical cross section, the imaginary straight line forming an angle θ with respect to the optical axis drawn from the light emission center is taken as a reference line, and the angle formed between the optical axis and the normal at the intersection of the reference line and the surface of the inner contour is ψ And the normal line at the intersection of the reference line and the outer contour surface. When the angle is δ, 0 ≦ δ ≦ 30 ° in the range of 0 ° ≦ θ ≦ 45 °, and ψ / θ is in the range of 0 ° <θ ≦ 15 °, preferably 5 ° ≦ θ ≦ 15 °. It has a maximum value (ψ / θ) becomes max angle _{θ x, θ x> ψ /} θ increases as theta increases in the range of theta, at least theta = 70 ° range in the range of theta> theta _x Until θ increases, ψ / θ decreases, and the distance on the reference line between the surface of the hemispherical transparent encapsulant and the surface of the concave inner contour becomes maximum when θ = 0 °, and 45 ° < The light emitting device with an optical member has an angle θy that minimizes the distance in a region in a range of θ ≦ 70 °. 0 ° has a <theta ≦ 15 ranges [psi / theta is the maximum value of ° (ψ / θ) becomes _max angle theta _x, and the scope of the shape of the exit surface of the optical member of 0 ° ≦ θ ≦ 45 ° By defining so that 0 ≦ δ ≦ 30 °, the light beam near the optical axis can be largely refracted. Further, by having an angle θ _y that is maximized when the distance is θ = 0 ° and is minimized in an area in a range of 45 ° <θ ≦ 70 °, the hemispherical transparent seal having a relatively small amount of light. The light distribution angle of the light beam in the range of 45 ° <θ ≦ 70 ° emitted from the stationary body can be widened. As a result, variation in illuminance distribution on the irradiated surface can be suppressed in a wide light distribution range.

  In the light emitting device with an optical member, when the distance on the reference line between the surface of the hemispherical transparent sealing body and the surface of the concave inner contour at the angle θ is D (θ), D (θ) = Acos. (Bθ) + C (where 0 ≦ θ ≦ 70 °, 0 ≦ A ≦ 1, 0 ≦ B ≦ 5, −1 ≦ C ≦ 1), and D (θ) is plotted against θ. In the graph, A, B, and C on the larger θ side are smaller than A, B, and C on the smaller θ side, with a change point existing in the range of 20 <θ <45 ° as a boundary. preferable. In such a case, the inclination of the concave inner contour in the angle range smaller than the change point is larger than the inclination of the concave inner contour in the angle range larger than the change point. As a result, the luminous flux can be greatly bent.

  Further, the outer contour is formed of a smooth curved surface that is convex upward and includes a plane in the vicinity of the optical axis in the range of at least 0 ° ≦ θ ≦ 45 °, and has an angle δ with respect to the minute change amount Δθ of the angle θ. When the ratio of the minute change Δδ is Δδ / Δθ, 0 ≦ Δδ / Δθ ≦ 0.2 in the range of 0 ° ≦ θ ≦ 20 °, and 0.05 ≦ in the range of 20 ° <θ ≦ 45 °. Δδ / Δθ ≦ 1.2, and further preferably 0.5 ≦ Δδ / Δθ ≦ 1.8 in the range of 45 ° ≦ θ ≦ 60 °. In such a case, the luminous flux emitted from the vicinity of the optical axis is preferably refracted by the outer contour of the optical member, and the variation in illuminance can be suppressed more optimally.

  Further, when the maximum height of the hemispherical transparent encapsulant is H1 and the maximum height of the optical member is H2 based on the surface of the light emission center of the semiconductor light emitting element, and H2 / H1 ≦ 3, This is preferable because the light distribution in a wide angle range can be maintained while the thickness is sufficiently reduced.

  Moreover, when it has the maximum relative light quantity in the range of angle (theta) y ± 15 degrees, it is preferable from the point which can fully reduce light distribution variation.

  Further, in the vicinity of the intersection with the optical axis, when the curvature of the concave inner contour is larger than the curvature of the hemispherical transparent encapsulant, the hemispherical transparent encapsulant concentrated much near the optical axis. This is preferable because light can be diffused more.

  The objects, features, aspects and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

  According to the present invention, a light distribution in a wide angle range is realized using an LED device including a hemispherical transparent encapsulant with a high concentration tendency near the center of the optical axis while suppressing variation in light emission on the irradiated surface. Can do.

FIG. 1A is a schematic top view of the light emitting device with an optical member 10 of the present embodiment, and FIG. 1B is a schematic cross-sectional view of the A-A ′ cross section of FIG. FIG. 2 is an explanatory diagram for explaining the details of the shape of the light emitting device 10 with an optical member. FIG. 3 is an explanatory diagram for explaining an example of the light propagation direction of the light emitting device with an optical member 10. FIG. 4 shows a graph in which ψ / θ is plotted with respect to θ of the light emitting device 10 with an optical member. FIG. 5 shows a graph plotting δ against θ of the light emitting device 10 with an optical member. FIG. 6 shows a graph in which the distance D on the reference line between the surface of the hemispherical transparent encapsulant 1c and the concave inner contour 5a of the optical member 5 with respect to θ of the light emitting device 10 with the optical member is plotted. FIG. 7 shows an example of a light intensity distribution diagram of an irradiation pattern of the light emitting device 10 with an optical member. FIG. 8 is an explanatory view illustrating a specific example of the dimensions of the light emitting device with an optical member 10. FIG. 9 is a schematic diagram for explaining an example of the shape of the back surface of the light emitting device 10 with an optical member. FIG. 10 is an explanatory diagram for explaining the light distribution of the planar LED package. FIG. 11 shows an example of a light intensity distribution diagram of an irradiation pattern of a planar LED package. FIG. 12 is an explanatory diagram for explaining the light distribution of the hemispherical LED package. FIG. 13 shows an example of a light intensity distribution diagram of an irradiation pattern of a hemispherical LED package. FIG. 14 is an explanatory view illustrating light distribution of a conventional light emitting device. FIG. 15 is an explanatory view illustrating light distribution of a conventional light emitting device.

  Hereinafter, an embodiment of a light emitting device with an optical member according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a light emitting device 10 with an optical member according to the present embodiment. FIG. 1A is a top view, and FIG. 1B is a cross-sectional view taken along the line AA ′ in FIG. is there. The light emitting device with an optical member 10 includes an LED device 1 including a LED element 1a that is a semiconductor light emitting element and a hemispherical transparent sealing body 1c that seals the LED element 1a, and an arrangement of light emitted from the LED element 1a. And an optical member 5 for controlling light.

  The LED device 1 includes a submount substrate 1b, an LED element 1a mounted on the submount substrate 1b, and a hemispherical transparent sealing body 1c that seals the LED element 1a. The submount substrate 1b includes lead terminals (not shown) on the bottom surface. As the LED element 1a, conventionally known LED elements that emit light in a wavelength region such as ultraviolet light, near ultraviolet light, visible light indicating wavelengths in the blue to red region, near infrared light, infrared light, and the like are particularly preferable. Used without limitation. Moreover, the phosphor layer for wavelength-converting the wavelength of the light emitted from the LED element 1a may be provided on the surface of the LED element 1a or in the vicinity thereof.

  The transparent encapsulant 1c has a hemispherical shape, and emits light emitted from the LED element 1a from the outer surface. As a specific example of the LED device provided with such a hemispherical transparent encapsulant, for example, NVSW119B, NVSL119B manufactured by Nichia Corporation having a hemispherical transparent encapsulant with a diameter of 2 to 3 mm, NS9W383 manufactured by Nichia Corporation, which has a hemispherical transparent sealing body with a diameter of 3 to 5 mm.

  In the present embodiment, as the LED device 1, an example using a light emitting device in which a light emitting element is mounted on a submount substrate and sealed with a hemispherical transparent sealing body will be described as a representative example. Instead of the LED device 1 as described above, an LED array obtained by arranging a plurality of light emitting elements on a single substrate and sealing each light emitting element in a hemispherical shape by overlay molding is described above. Such an optical member may be mounted. In this case, the optical member may be mounted as an independent optical member or as a lens array formed by integrating a plurality of the optical members described above.

  The optical member is molded by, for example, cast molding, compression molding, injection molding, or the like. The transparent material for forming the transparent sealing body and the optical member is not particularly limited as long as it is a material excellent in light transmittance. Specifically, for example, transparent resin such as silicone gel, silicone elastomer, silicone rubber, hard silicone resin, silicone modified epoxy resin, epoxy resin, silicone modified acrylic resin, acrylic resin, organic glass, inorganic glass, etc. Can be mentioned. Among these, from the point that it is excellent in light transmissivity, and the stress due to heat shock etc. at the time of high temperature reflow mounting using lead-free solder is eased, and a lens excellent in deformation resistance and discoloration resistance can be obtained. Particularly preferred are silicone elastomers, silicone rubbers and silicone resins. In addition, the transparent resin diffuses the phosphor for converting the emission color and the light by converting the wavelength of the light emitted from the LED element as necessary within the range not impairing the effect of the present invention. A light diffusing agent or the like may be included.

  When the optical member is formed in a shape that is optically symmetric with respect to the optical axis of the light emitted from the semiconductor light emitting element, the optical member emits light from the semiconductor light emitting element from the optical axis center to its periphery. It is preferable from the point that it can distribute light uniformly. Depending on the application, if it is desired to distribute light in a specific direction in the plane direction, an elliptical shape or an asymmetric shape with respect to the optical axis or a left-right asymmetric shape may be used.

  As shown in FIG. 1B, the optical member 5 includes a concave inner contour 5a for accommodating the hemispherical transparent sealing body 1c, a bottom contour 5b connected to the periphery of the inner contour 5a, and a bottom contour 5b. And an outer contour 5c. Moreover, you may provide the fitting shape for fixing the LED apparatus 1 so that it may mention later in the opening part of the inner side outline 5a, and the bottom face outline 5b.

  FIG. 2 is an explanatory diagram for explaining the contour shape of the hemispherical transparent sealing body 1 c and the contour shape of the optical member 5 for explaining the shape of the light emitting device with an optical member 10. Moreover, FIG. 3 is explanatory drawing which shows an example of the propagation direction of the light light-emitted from the LED element 1a of the light-emitting device 10 with an optical member.

  As shown in FIG. 3, in the light emitting device with an optical member 10, the interface (I) formed by the outline of the transparent sealing body 1c, the interface (II) between the space S and the optical member 5, the optical member 5 and the outside And a total of three interfaces (III). At each interface, light is refracted according to Snell's law. The light emitted from the LED element 1a enters the transparent sealing body 1c and then exits from the interface (I) which is a hemispherical exit surface of the transparent sealing body 1c. At this time, the light beam is refracted so as to be condensed in the optical axis direction at the interface (I). The refracted light beam travels straight in the space S between the transparent sealing body 1c and the concave inner contour 5a, reaches the concave inner contour 5a, and the interface between the space S and the concave inner contour 5a. The light is refracted in (II) and enters the optical member 5. The light beam incident on the optical member 5 travels straight to the outer contour 5c of the optical member 5, and is refracted and emitted so that the angle formed with the optical axis is increased at the interface (III) formed by the outer contour 5c. The irradiated surface 6 is irradiated.

  As shown in FIG. 2, the light emitting device with an optical member 10 uses an imaginary straight line formed from the light emission center 1 a ′ that forms an angle θ with respect to the optical axis L as a reference line SD, and the optical axis L and the reference line SD. The angle formed by the normal line at the intersection A with the surface contour of the hemispherical transparent sealing body is φ, the angle formed by the normal line at the intersection B between the reference line SD and the surface of the inner contour is ψ, and the reference line SD and the outside When the angle formed with the normal line at the intersection C with the contour surface is δ, the following features are obtained.

As shown in FIG. 4, the concave inner contour 5a of the optical member 5 has a maximum value (ψ / θ) _max of ψ / θ within a range of 0 ° <θ ≦ 15 °, preferably 5 ° ≦ θ ≦ 15 °. has to become angle _{θ x, θ x> ψ /} θ increases as theta increases in the range of θ, θ> θ is theta = 70 ° in the range of _x, preferably 80 °, more preferably 90 ° Up to this range, ψ / θ decreases as θ increases. Here, ψ / θ is a parameter that defines an incident angle when light emitted from the LED element 1a at an angle θ is incident on the concave inner contour 5a, and the larger ψ / θ is, the larger the value is. This indicates that the refraction angle at the interface of the concave inner contour 5a is increased. In the light emitting device with an optical member 10, by having an angle θ _x where ψ / θ is a maximum value (ψ / θ) _max in a range of 0 ° <θ ≦ 15 °, as shown in E of FIG. The interface of the concave inner contour 5a can refract the light condensed in the vicinity of the optical axis so that the angle formed from the optical axis becomes large.

The value of (ψ / θ) _max is 1.2 to 8, more preferably 2 to 5, particularly 2.5 to 4, and most preferably about 3 to 3.5. Is preferable from the viewpoint of realizing a high illuminance distribution. When the value of (ψ / θ) _max is too small, the angle at which the light collected near the optical axis is refracted becomes small. As a result, the diffusion effect is reduced, and the illuminance near the optical axis is reduced. There is a tendency that the variation in illuminance distribution increases due to the increase. On the other hand, if it is too large, the light flux in the vicinity of the optical axis becomes too small and an excessive diffusion effect is obtained, and the illuminance in the vicinity of the optical axis tends to decrease and the variation in the illuminance distribution tends to increase. Further, the value of ψ / θ at 0 <θ <5 ° in the vicinity of the optical axis is about 1 to 5, more preferably about 2 to 3, and particularly about 2.5 to 3 near the optical axis on the irradiated surface. This is preferable from the viewpoint that the light distribution can be appropriately left.

FIG. 5 shows a graph plotting δ with respect to θ of the light emitting device 10 with an optical member. As shown in the graph of FIG. 5, the outer contour 5c of the optical member 5 is defined so as to satisfy 0 ≦ δ ≦ 30 ° in the range of 0 ° ≦ θ ≦ 45 °. As shown in E of FIG. 3, the concave inner contour 5a is, if it has a 0 ° <θ ≦ 15 ranges [psi / theta is the maximum value of ° (ψ / θ) becomes _max angle theta _x, concave inner Due to the interface of the contour 5a, the light beam near the optical axis is refracted so that the angle with respect to the optical axis becomes large. In this case, by defining the shape of the outer contour 5c of the optical member 5 so as to satisfy 0 ≦ δ ≦ 30 ° and further 0 ≦ δ ≦ 20 ° in the range of 0 ° ≦ θ ≦ 45 °, The incident angle of the light beam near the optical axis refracted by the inner contour 5a to the interface of the outer contour 5c can be increased, and as a result, the light is refracted so that the angle with respect to the optical axis is increased.

  The outer contour 5c of the optical member 5 has a flat surface in the vicinity of the optical axis, and is continuously convex upward in the range of 0 ° ≦ θ ≦ 45 °, and further in the range of 0 ° ≦ θ ≦ 60 °. In the range of 0 ° ≦ θ ≦ 5 °, 0 ° ≦ δ ≦ 5 °, and in the range of 5 ° <θ ≦ 30 °, 0 ° ≦ δ ≦ 10 ° In the range of 30 ° <θ ≦ 45 °, 2 ≦ δ ≦ 30 °, and in particular, in the range of 45 ° <θ ≦ 60 °, 5 ≦ δ ≦ 45 ° is preferable. . By defining the shape of the outer contour 5c that is the exit surface of the optical member 5 in this way, the incident angle of the light beam near the optical axis with respect to the exit surface of the optical member 5 can be sufficiently increased, and as a result, diffusion It can be refracted greatly in the direction.

  In particular, the outer contour 5c of the optical member 5 preferably has a range of θ where δ = 0 ° in a range of 0 ° ≦ θ <10 °. Further, in the range of 10 ° ≦ θ ≦ 45 °, it is preferable that δ continuously increases with an increase in θ. Furthermore, in the range of 0 ° ≦ θ ≦ 45 °, it is preferable that δ does not decrease when θ increases. In such a case, it is preferable from the viewpoint that variation in illuminance distribution can be effectively suppressed without excessively reducing the illuminance in the vicinity of the optical axis.

  Further, when the ratio of the minute change amount Δδ of the angle δ to the minute change amount Δθ of the angle θ is Δδ / Δθ, 0 ≦ Δδ / Δθ ≦ 0.2 in the range of 0 ° ≦ θ ≦ 20 °, and 20 It is specified that 0.05 ≦ Δδ / Δθ ≦ 1.2 in the range of ° <θ ≦ 45 ° and 0.5 ≦ Δδ / Δθ ≦ 1.8 in the range of 45 ° ≦ θ ≦ 60 °. It is preferable. In such a case, the light in the condensing direction can be refracted by the outer contour, and variation in illuminance can be further suppressed.

FIG. 6 is an example in which the distance D on the reference line between the surface of the hemispherical transparent sealing body 1c and the surface of the concave inner contour 5a is plotted with respect to the angle θ of the light emitting device with an optical member 10 of the present embodiment. is there. As shown in FIG. 6, the distance D between the surface of the hemispherical transparent sealing body 1c and the surface of the concave inner contour 5a is maximum when θ = 0 °, and is in a range of 45 ° <θ ≦ 70 °. The angle θ _y that minimizes the distance is preferably in a region in the range of 50 ° <θ ≦ 65 °. FIG. 6 shows an example when θ _y = 55 °. Note that the distance D changes within a range of θ> θ _y so that D gradually increases as θ increases in at least a range of θ <70 °.

  As shown in FIG. 13, in the LED package provided with the hemispherical transparent encapsulant, there is a tendency to condense in the optical axis direction, so that the light quantity is relative in the range of 45 ° <θ ≦ 70 °. Less. It is preferable to control the light distribution so that the light flux in such a range is not collected in the optical axis direction as much as possible. When the light emitted from the hemispherical transparent sealing body 1c enters the space S having a refractive index smaller than that of the transparent sealing body 1c, the light is refracted in the optical axis direction at the interface between the transparent sealing body 1c and the space S. . In this case, the longer the distance traveling straight through the space S, the easier it is to collect light in the optical axis direction. Therefore, as shown in FIG. 3F, the luminous flux emitted in the range of 45 ° <θ ≦ 70 ° passes through the space S at a short distance and enters the optical member 5, thereby distributing the luminous flux in this region. Can be widened.

  More specifically, the distance between the surface of the hemispherical transparent encapsulant and the surface of the concave inner contour is, for example, the surface of the hemispherical transparent encapsulant at the angle θ and the surface of the concave inner contour. When the distance on the reference line SD is D (θ), D (θ) = Acos (Bθ) + C (where 0 ≦ θ ≦ 70 °, 0 ≦ A ≦ 1, 0 ≦ B ≦ 5, − 1 ≦ C ≦ 1), and a graph in which D (θ) is plotted with respect to θ, A, B, Each C is preferably smaller than each of A, B, and C on the side where θ is small. In the graph of FIG. 6, the change point X exists at θ = 28.9 °, and D (θ) = 0.3 cos (3.8θ) +0.45 when 0 <θ <28.9 °. 28.9 ° ≦ θ ≦ 85 °, D (θ) = 0.23 cos (3.3θ) +0.37. In such a case, when the ratio of the minute change amount ΔD (θ) of D (θ) to the minute change amount Δθ of θ representing the inclination of the concave inner contour is ΔD (θ) / Δθ, the change point X The maximum value of ΔD (θ) / Δθ in the smaller angle range is larger than the maximum value of ΔD (θ) / Δθ in the angular range larger than the change point X.

Due to the presence of such a change point X, the distance becomes the shortest at an angle θ _y of θ> 45 °. According to such a shape, theta> 45 and ° angle theta surface _y hemispherical transparent encapsulant 1c and concave inner contour 5a of the surface of the optical member 5 is closest. In this region, as shown in FIG. 3F, the light emitted from the hemispherical transparent sealing body 1c is refracted in the direction of the optical axis and travels through the space S. The optical path is bent in the direction in which the angle formed with respect to the inner contour 5a and the angle formed with respect to the optical axis increases. Thereby angle light emitted from the transparent encapsulant 1c near the angle theta _y is to minimize the rectilinear length of the direction parallel to the optical axis enters by refraction in the optical element, straight through the optical member As a result, the outer contour 5c reaches a position away from the optical axis, and the angle formed with the optical axis is further increased due to refraction at the exit surface of the optical member 5. That is, the light refracted in the condensing direction emitted at θ> 45 ° can be refracted in the diffusing direction at the interface of the concave inner contour 5a before proceeding almost in the condensing direction.

The distance between the concave inner contour 5a and the outer surface of the transparent sealing body 1c is appropriately adjusted depending on the size of the transparent sealing body 1c. Specifically, for example, the bottom surface of the hemispherical sealing body Is about 2 to 3 mm, the distance between the surface of the hemispherical transparent sealing body 1c and the concave inner contour 5a at the angle θ _y that makes the shortest is 5 to 1000 μm, It is preferably about 500 μm, particularly about 50 to 300 μm. If the distance at the angle θ _y at which the interval is the shortest is too long, the overall shape of the optical member 5 tends to increase.

  Further, the distance D at θ = 0 °, which is the longest distance between the surface of the hemispherical transparent encapsulant 1c and the concave inner contour 5a, is appropriately adjusted depending on the size of the transparent encapsulant 1c. Specifically, for example, when the diameter of the bottom surface of the hemispherical sealing body is about 2 to 3 mm, it is preferably about 400 to 5000 μm, further about 400 to 2000 μm, and further about 500 to 1000 μm. When the distance at θ = 0 ° is too long, the height of the optical member 5 tends to increase. When the distance at θ = 0 ° is too short, the inclination of the interface (II) in the region that forms an angle within 45 ° from the emission center with respect to the optical axis becomes gentle, and as a result, the interface (II) There is a tendency that the incident angle of light with respect to becomes smaller.

Also, is adjusted appropriately depending on the size of theta = 0 the ratio of a distance in the distance and theta = theta _y in ° transparency encapsulant 1c, specifically, for example, the bottom surface of the hemispherical sealing member diameter When it is about 2 to 3 mm, D (0 °) / D (θ _y ) = 1.1 to 500, further 1.3 to 20, and more preferably about 2 to 10 On the other hand, since the inclination of the interface (II) in a region having an angle of 45 ° or more can be sufficiently increased, it is preferable from the viewpoint that the incident angle of light with respect to the interface (II) can be increased.

  As described above, in the light emitting device with an optical member 10, the interface (I) formed by the outline of the transparent sealing body 1c, the interface (II) between the space S and the optical member 5, and the interface between the optical member 5 and the outside. The light distribution is adjusted by correlating a total of three interfaces (III). Therefore, it is possible to perform light distribution with a wide light distribution angle while suppressing an increase in the height of the optical member 5 and suppressing variations in illuminance distribution on the irradiation surface. Specifically, for example, referring to FIG. 2, when the maximum height of the transparent sealing body 1c from the surface of the LED element 1a is H1, and the maximum height of the optical member 5 from the surface of the LED element 1a is H2. H2 / H1 ≦ 3, and even H2 / H1 ≦ 2.5, even if the height of the optical member 5 is not so high compared to the height of the transparent sealing body 1c, the transparent sealing body 1c Almost all the emitted light is well controlled.

  In order to prevent the height of the optical member 5 from increasing, the distance between the concave inner contour 5a and the outer contour 5c on the optical axis of the optical member 5, that is, the thickness of the optical member on the optical axis is set to t. And the diameter of the bottom surface of the hemispherical transparent encapsulant of the LED device 1 is preferably adjusted so that t / W ≦ 0.13 holds. By setting t / W to 0.13 or less, a desired outer contour shape can be maintained, and the passage distance of light propagating through the optical member can be minimized. For this reason, the thickness and diameter of the entire optical member can be reduced.

  In addition, as shown in FIG.1 (b), the light-emitting device 10 with an optical member is formed so that the curvature of the concave inner outline 5a is larger than the curvature of the hemispherical transparent sealing body 1c in the vicinity of the optical axis. Has been. By forming in this way, the amount of light in the vicinity of the optical axis can be diffused in a direction where the angle formed with the optical axis is larger.

  Each refractive index of the transparent sealing body 1c, the space S between the concave inner contour 5a and the outer surface of the transparent sealing body 1c, and the optical member 5 is appropriately set according to the required light distribution characteristics. The refractive index of the space S is the smallest. From such a viewpoint, as the space S, an air layer or a transparent material layer having a low refractive index is selected. More specifically, the refractive index of the space S is preferably smaller than the refractive index of the transparent encapsulant 1c and the optical member 5 by 0.2 or more, and more preferably by 0.3 or more.

  In FIG. 7, an example of the light intensity distribution figure of the irradiation pattern of the light-emitting device 10 with an optical member is shown. In addition, the irradiation pattern shown in FIG. 7 was obtained by the light emitting device 10 with an optical member having a dimension as shown in FIG.

That is, with reference to FIG. 8, the optical member 5 has a substantially circular lens shape when viewed from above, the diameter thereof is 8.0 mm, and the maximum height with respect to the upper surface of the LED element 1a is 2.4 mm. The inner diameter of the bottom surface is 3.5 mm. Further, the outer shape is specified by the graphs of FIGS. 4 to 6, the angle θ _x at which (ψ / θ) _max is 10 °, the change point X is 28.9 °, and a hemispherical transparent sealing body The angle θ at which the distance between the surface and the concave inner contour becomes the shortest was 55 °, and the distance at that time was 0.14 mm. The curvature radius R1 of the top surface of the concave inner contour was 0.654 mm. Furthermore, the refractive index of the optical member 5 was 1.41.

  On the other hand, the LED device 1 includes a square LED element having a side of 1 mm, a hemispherical transparent sealing body having a height of 1.44 mm, a bottom surface diameter of 2.54 mm, and a hemispherical radius of curvature R2 of 1.25 mm. In the optical axis direction, the distance from the top surface of the hemispherical transparent encapsulant to the concave inner contour was 0.75 mm, and the refractive index of the transparent encapsulant was 1.52.

  As shown in FIG. 7, in the light emitting device with an optical member 10, light distribution is controlled so that the maximum relative light amount exists in the vicinity of + 65 ° and −65 ° with respect to the optical axis. The relative intensity at θ = 0 ° is about 0.22 with respect to the maximum peak intensity 1 near −65 °. Further, the relative intensity in the vicinity of ± 30 ° is about 0.3. Moreover, it is about 0.4 at around ± 80 ° and about 0.6 at around ± 50 °, indicating that the light distribution is relatively small in a wide range. Compared with the light distribution of the LED package provided with the hemispherical sealing body shown in FIG. 13, in the light emitting device with an optical member, condensing in the optical axis direction is clearly suppressed, and a wide light distribution range is obtained. It can be seen that the illuminance is uniform.

  In FIG. 7, the light distribution is controlled so that the maximum relative light quantity exists in the vicinity of + 65 ° and −65 °. As an example, as shown in FIG. 6, in the light emitting device with an optical member 10, θy at which the distance between the surface of the hemispherical transparent sealing body 1 c and the surface 5 a of the concave inner contour is the shortest is 55 °. As described above, in the light emitting device with an optical member 10 of the present embodiment, the angle indicating the maximum relative light amount is preferably located in the vicinity of the angle of the absolute value of θy ± 15 °, further θy ± 10 °. In such a case, it is particularly preferable from the viewpoint that variation in light distribution can be sufficiently reduced.

  Note that a reflective film may be formed on the bottom surface of the optical member 5 including the bottom surface contour 5b. By forming such a reflection film, a slight light having a large angle with respect to the optical axis generated from the light emitting element or stray light generated inside the optical member 5 is reflected to the emission surface side to extract light. Efficiency can be improved. Examples of such a reflective film include a white reflective film made of a resin composition containing a white filler, and a metal reflective film.

  The basic configuration and the effect of the light emitting device with an optical member according to the present embodiment have been described above. In the light emitting device with an optical member of the present embodiment, the method for attaching the optical member to the semiconductor light emitting device such as the LED device is not particularly limited. For example, as described below, the submount substrate is fixed to the optical member. There is no particular limitation such as providing such a fitting shape, bonding with an adhesive, or providing an engaging portion such as a snap-fit shape. When the layer between the surface of the hemispherical transparent encapsulant 1c and the optical member 5 is a low refractive index transparent resin layer, the optical member and the low refractive index resin layer are formed simultaneously or individually. After the molding, they may be fitted together, and then the LED package may be bonded with an adhesive, or the optical member 5 and the LED package may be filled with a low refractive index and transparent adhesive.

  An example of providing a fitting shape for fixing the submount substrate to the optical member will be described with reference to FIG. FIG. 9A shows a state before the LED device 1 is mounted on the optical member 25 which is an example of the optical member of the present embodiment, and FIG. 9B shows a state after the mounting. Although this embodiment shows a case where the sub-mount substrate has one light emitting element, it can be similarly applied to a light source in which a plurality of light emitting elements are mounted on the same substrate.

  The optical member 25 includes a flange portion 26 for supporting the LED device 1 on the bottom surface thereof. As shown in FIG. 9A, the flange portion 26 has a digging groove 26a that is connected to the concave portion of the optical member 25 so that the hemispherical transparent sealing body 1c of the LED device 1 enters the concave portion of the optical member 25. Is formed. For example, when the submount substrate 1b is square, the digging groove 26a has a fitting shape 26b that fixes the substrate on four sides of the submount substrate. Moreover, when the shape of the anode mark or the cathode mark indicating the terminal polarity direction is formed on the submount substrate 1b, a notch shape for determination may be given to the corner portion of the flange portion 26. According to such a shape, the direction of the terminal polarity of the LED device 1 can be easily adjusted.

  Further, when the layer between the surface of the hemispherical transparent encapsulant 1c and the optical member 5 is an air layer, as shown in FIG. 9, as a part of the digging groove 26a, the optical member 25 You may provide the vent hole 26c which does not seal the inside of a recessed part, but communicates with the exterior. When the layer between the surface of the hemispherical transparent encapsulant 1c and the optical member 5 is an air layer, when the reflow process is passed when the light emitting device with an optical member is mounted on a circuit board, the heat applied during the reflow As a result, the air expands. When the air layer is sealed, the expanded air causes the position of the optical member 2 relative to the hemispherical transparent sealing body 1c of the LED device 1 to deviate from a predetermined position, and the optical member 25 is When bonded to the submount substrate 1b, the optical member may peel off due to expansion of the air layer. In the case where the vent hole 26c as described above is provided, the expanded air can be released to the outside, so that the positional displacement and peeling of the optical member 5 as described above can be suppressed.

  Moreover, when fixing a submount board | substrate to an optical member by the above fitting shapes, you may fix with an adhesive agent. The type of the adhesive is not particularly limited as long as it is a low refractive index adhesive, but for example, a transparent adhesive having heat resistance and discoloration resistance such as a silicone adhesive is preferable. In the case of fixing with an adhesive, in order to prevent the adhesive overflowing from the adhesive portion from adhering to the surface of the submount substrate, as shown in FIG. A recess 26d for accommodating the overflowing adhesive may be provided.

DESCRIPTION OF SYMBOLS 1 LED apparatus 1a LED element 1b Submount board | substrate 1c Hemispherical transparent sealing body 5,25 Optical member 5a Inner outline 5b Bottom outline 5c Outer outline 6 Irradiated surface 10 Light-emitting device with an optical member 26 Flange part 26a Digging groove 26b Fit Combined shape 26c Vent hole 26d Depression for accommodating adhesive A, B, C Intersection L Optical axis S Space SD Reference line X Change point

Claims (9)

A light emitting device including a semiconductor light emitting element and a hemispherical transparent sealing body that seals the semiconductor light emitting element, and an optical member for controlling the light distribution characteristics of light emitted from the semiconductor light emitting element,
Between the surface of the transparent encapsulant and the optical member, there is further a layer having a refractive index smaller than that of the transparent encapsulant and the optical member,
The shape of the optical member is
A concave inner contour for accommodating the hemispherical transparent sealing body, and an outer contour defining the contour of the light exit surface,
An imaginary straight line forming an angle θ with respect to the optical axis drawn from the light emission center in an arbitrary longitudinal section cut along a plane including the optical axis, with the vertical axis with respect to the light emission surface at the light emission center of the semiconductor light emitting element. Is the reference line, the angle between the optical axis and the normal line at the intersection of the reference line and the surface of the inner contour is ψ, and the normal line at the intersection of the reference line and the surface of the outer contour is If the angle formed is δ,
0 ≦ δ ≦ 30 ° in the range of 0 ° ≦ θ ≦ 45 °,
An angle θ _x where ψ / θ is a maximum value (ψ / θ) _max in a range of 0 ° <θ ≦ 15 °,
In the range of θ _x > θ, ψ / θ increases as θ increases, and in the range of θ> θ _x ψ / θ decreases as θ increases up to at least the range of θ = 70 °,
The distance on the reference line between the surface of the hemispherical transparent encapsulant and the surface of the concave inner contour is maximum when θ = 0 °, and the distance is within the range of 45 ° <θ ≦ 70 °. A light-emitting device with an optical member, characterized in that the angle θ _y has a minimum value. When the distance on the reference line between the surface of the hemispherical transparent sealing body and the surface of the concave inner contour at an angle θ is D (θ),
D (θ) = Acos (Bθ) + C (where 0 ≦ θ ≦ 70 °, 0 ≦ A ≦ 1, 0 ≦ B ≦ 5, −1 ≦ C ≦ 1),
In the graph in which D (θ) is plotted against θ, A, B, and C on the side where the θ is large, with the change point existing in the range of 20 <θ <45 ° as a boundary, the θ is small. The light emitting device with an optical member according to claim 1, which is smaller than each of A, B, and C on the side.   The outer contour is an upward convex smooth curved surface including a plane in a range of at least 0 ° ≦ θ ≦ 45 °, and the ratio of the minute change amount Δδ of the angle δ to the minute change amount Δθ of the angle θ. In the case of Δδ / Δθ, 0 ≦ Δδ / Δθ ≦ 0.2 in the range of 0 ° ≦ θ ≦ 20 °, and 0.05 ≦ Δδ / Δθ ≦ 1.2 in the range of 20 ° <θ ≦ 45 °. The light emitting device with an optical member according to claim 1 or 2.   2. When the maximum height of the hemispherical transparent encapsulant is H1 and the maximum height of the optical member is H2 with respect to the surface of the light emission center of the semiconductor light emitting element, H2 / H1 ≦ 3. The light emitting device with an optical member according to any one of? 5. The light emitting device with an optical member according to claim 1, wherein the light emitting device has a maximum relative light amount in a range of an angle θ _y ± 15 °.   The light emitting device with an optical member according to claim 1, wherein the layer having a low refractive index is an air layer.   The light emitting device with an optical member according to claim 1, wherein a refractive index of the layer having a small refractive index is 0.3 or more smaller than a refractive index of the hemispherical transparent encapsulant. 5 ° ≦ θ ≦ 15 ranges [psi / theta is the maximum value of ° (ψ / θ) optical element with the light-emitting device according to any one of claims 1 to 7 having an angle theta _x becomes _max.   The light emitting device with an optical member according to any one of claims 1 to 8, wherein a curvature of the concave inner contour is larger than a curvature of the hemispherical transparent sealing body in the vicinity of an intersection with the optical axis.

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