JP4665832B2 - Light emitting device and white light source and lighting device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase a light deriving efficiency and suppress a color shift in a light emitting device wherein, to achieve such a light emitting device as a white light source, its light emitting element of a light emitting diode, etc. is contained in a dome-form wavelength converting member, and the light radiated from the light emitting element is made outgoing by converting it into a desired-wavelength light. <P>SOLUTION: In the light emitting device, the cross-sectional shape of the outer surface of a transparent member 5 to become a light outgoing surface to air is so formed as to be a semi-ellipse R. The focuses F1, F2 of the semi-ellipse R are the two intersections where the outer tangential circle of a light emitting element 2 intersects a surface to perform the luminous-intensity control of the device. Further, the gap angle &theta; between the normal V at each point P and the line segment of the point P and the focus F1 (F2) is so set as to be smaller than the total-reflection angle of the transparent member 5. That is, the semi-ellipse R is so set as to fall within the scope between a semicircle R2 and a semi-ellipse R1 whose gap angle is smaller than the total-reflection angle of the transparent member 5. Therefore, while preventing the total reflection in the light outgoing surface of the transparent member 5 in comparison with a shell type shape, etc., a wavelength converting member 7 is so made to approximate closely to the light emitting element 2 that the light having a high center luminance and a few color shift can be obtained, that the light radiated from the side surface of the device is reduced, further, that the light deriving efficiency to the front-surface direction of the device can be increased. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a light-emitting device that includes a light-emitting element in a dome-shaped wavelength conversion member, converts the light emitted from the light-emitting element to a desired wavelength, and emits the light, and a white light source and an illumination device using the same. .

A typical example in which a light emitting element is included in a dome-shaped wavelength conversion member as described above so that the light emitted from the light emitting element is converted into a desired wavelength and emitted so that it can be used in an illumination device or the like. Such a prior art light-emitting device is disclosed in Patent Document 1, for example. According to the prior art, a light emitting diode light emitting diode is covered with a translucent coating material containing a fluorescent material, thereby converting the light emitting color of the light emitting diode into a desired color.
Japanese Patent Laid-Open No. 11-87784

  In the above-described prior art, since the light emitting diode has a bullet-shaped shape, it is large and has a large amount of radiation from the side surface (many normals of the light emitting surface face sideways and the radiation component in the front direction). There is a problem that the light extraction efficiency is low. Further, since the distance between the wavelength conversion member and the light emitting element is increased, the density of the excitation light applied to the wavelength conversion member is low, and as a result, the emitted light becomes light with low color intensity and high color shift. .

  An object of the present invention is to encapsulate a light emitting element in a dome-shaped wavelength conversion member, improve the light extraction efficiency in converting the light emitted from the light emitting element into a desired wavelength and emitting it, To provide a white light source and an illuminating device with little deviation.

The light-emitting device of the present invention is a light-emitting device that includes a light-emitting element between a substrate and a dome-shaped wavelength conversion member , converts light emitted from the light-emitting element into a desired wavelength, and emits the light. The light emission surface to the dome-shaped air is cut in a plane perpendicular to the substrate and the light emitted from the light-emitting element is to be light-distributed, and the cross-sectional shape is light emission from the cut surface. A semi-ellipse having a focal point at two intersections with a circle circumscribing the element, and the angle formed between the normal line at each point on the semi-ellipse and each focal point is the total reflection of the member forming the light emitting surface It is a range from a semi-ellipse to a semi-circle having an angle less than an angle.

According to said structure, in order to implement | achieve light-emitting devices, such as a white light source, light emitting elements, such as a light emitting diode, are included in a dome-shaped wavelength conversion member, and the light radiated | emitted from the said light emitting element is converted into a desired wavelength. In the light emitting device that emits light, the light emitting surface to the dome-shaped air, such as the outer surface of the wavelength conversion member or the outer surface of the transparent member when the light emitting element is covered with the transparent member, A cross-sectional shape cut by a surface perpendicular to the substrate to be subjected to light distribution control is a semi-elliptical shape having a focal point at two intersections between the cut surface and a circle circumscribing the light emitting element. Therefore, the two focal points are corners on a diagonal line when the light emitting surface of the light emitting element is a square or a regular hexagon. However, when the angle formed between the normal line at each point on the semi-ellipse and each focal point is the total reflection angle of the member forming the light exit surface, for example, the resin having a refractive index of 1.53, 40. If it is not less than 8 °, it will be totally reflected, so that a semi-ellipse having an angle less than that angle, that is, the semi-ellipse is not flattened in the plane direction of the light emitting element, so that it does not become a flat shape. The semi-elliptical shape is defined.

  Therefore, even if the light exit surface is a flat semi-elliptical shape to a semi-circular shape, while preventing total reflection due to a difference in refractive index between the wavelength conversion member or the transparent member and air on the light exit surface, more than a semicircle Compared with, for example, a bullet-shaped shape, the size can be reduced and radiation from the side surface can be reduced (radiation in the front direction can be achieved by directing most of the normals of the light exit surface to the front direction). The light extraction efficiency can be increased. Furthermore, since the distance between the wavelength conversion member and the light emitting element is close, it is possible to increase the density of the excitation light irradiated to the wavelength conversion member. The light can be emitted from the conversion member.

The light emitting device of the present invention, the light emitting element is enclosed in a transparent member of the high have refractive index than air having a property of transmitting light, further to the wavelength converting member of the dome-shaped at a gap of predetermined distance It is included.

  According to the above configuration, the light emitted from the light emitting element can be taken out efficiently by enclosing the light emitting element with a transparent member having a high refractive index such as silicone having a property of transmitting light. Can also be protected.

  Furthermore, in the light emitting device of the present invention, the light emitting element is mounted on a substrate and is sealed by the substrate and the transparent member, and the transparent member is formed so that a peripheral portion is separated from the substrate. It is characterized by having a slope.

  According to the above configuration, by cutting (chamfering) the peripheral edge portion of the transparent member having a high refractive index into a slope, the slope becomes a reflective surface that reflects light emitted from the light-emitting element sideward, and The light utilization efficiency can be improved and the beam angle can be reduced.

  In the light emitting device of the present invention, the transparent member is constituted by a dome-shaped outer shell and an inner member filled between the outer shell and the light emitting element, and the inner member is compared with the outer shell. It is characterized by being made of a material having a relatively low refractive index.

  According to said structure, as said transparent member, the two-layer structure of the outer shell which has a dome shape, and the inner member with which it fills between the outer shell and a light emitting element is used, Furthermore, the said inner member is outer shell It is formed from a material having a relatively low refractive index compared to the above.

  Accordingly, the light emitted from the light emitting element to the side (peripheral edge direction of the dome-shaped transparent member) due to the difference in refractive index is also directed to the front direction (ceiling of the dome) at the interface between the inner member and the outer shell. Direction) and incident at an angle close to perpendicular to the ceiling portion of the dome-shaped wavelength conversion member, and the color shift can be further reduced, and the interface from the air layer to the wavelength conversion member in the gap Can be prevented, and the light extraction efficiency can be further increased. In addition, the light-emitting element can be protected by employing an elastic gel or rubber for the inner member.

  Furthermore, the light emitting device of the present invention is characterized in that the thickness of the outer shell is uniform.

  According to said structure, since the optical path length when the light radiate | emitted from the light emitting element permeate | transmits an outer shell becomes substantially equal, the brightness nonuniformity in the light-projection surface of the said transparent member can be reduced.

  In the light emitting device of the present invention, the wavelength conversion member has a convex portion that protrudes in a direction in which light is emitted at least in a region overlapping with the light emitting element.

  According to said structure, a convex lens is formed in the light extraction surface of a wavelength conversion member when it sees on the surface which should perform the said light distribution control. The convex lens may be formed only in the central portion overlapping the light emitting element, or may be formed entirely.

  Therefore, light with higher central luminance can be emitted by the light condensing effect of the convex lens.

  Furthermore, in the light emitting device of the present invention, the concentration of the phosphor that converts the wavelength of incident light in the wavelength conversion member is relatively high on the light emitting element side and thin on the emission surface side of the wavelength conversion member. It is characterized by being distributed continuously or stepwise.

  According to said structure, even if the convex lens is formed in the wavelength conversion member as mentioned above, the wavelength conversion in the convex lens part is slight, and most of wavelength conversion is inside the said dome-shaped wavelength conversion member. It is performed over the entire surface (on the light emitting element side).

  Therefore, even if the convex lens portion is provided, the color shift between the light emitted from the peripheral portion of the dome-shaped wavelength conversion member and the light emitted from the ceiling portion (convex lens portion) can be reduced.

  In the light emitting device of the present invention, the wavelength conversion member transmits the light from the light emitting element to the inner surface facing the transparent member, and reflects the light generated by wavelength conversion by the wavelength conversion member. It is characterized by providing.

According to the above configuration, for example, the wavelength filter formed by alternately laminating SiO ₂ and TiO ₂ allows light incident on the wavelength conversion member from the light emitting element to pass through as it is, and is wavelength-converted by the wavelength conversion member to be the light emitting element. Since the light returning to the side is reflected in the wavelength conversion member, the light extraction efficiency can be further increased. In addition, the wavelength filter can selectively transmit only the light in the wavelength band that is efficiently converted by the phosphor, and the uniformity of the color of the converted light can be improved. Furthermore, in general, light emitted from a light emitting element is in a short wavelength band, and when the wavelength filter transmits the component, light in a long wavelength band that causes a temperature rise enters from the outside of the light emitting device and emits light. Reaching the element can be prevented and deterioration of the light emitting element can also be prevented.

  Furthermore, the light-emitting device of the present invention is characterized in that an antireflection structure is provided on at least one light incident / exit surface of the wavelength converting member and the transparent member.

According to the above configuration, for example, an antireflection film formed by alternately laminating SiO ₂ and TiO _{2 on} at least one light incident / exit surface of the wavelength conversion member and the transparent member, or more than the desired wavelength. By providing a concave-convex structure with a short interval, for example, a reflection loss occurring about 4% can be suppressed to about 1% or less, and the light extraction efficiency can be further improved.

  The white light source of the present invention is characterized by using the above light emitting device.

  According to said structure, by using said light-emitting device, while being able to improve light extraction efficiency, the white light source which cannot produce color unevenness easily is realizable.

  Furthermore, in the illumination device of the present invention, the white light source is provided with an optical member for controlling light distribution from the light exit surface on the light exit surface side of the wavelength conversion member. It is characterized by that.

  According to the above configuration, since the light emitted from the white light source is diffused light, the use of the illumination device can be expanded by controlling the light distribution at a narrow angle in combination with an optical member such as a lens or a prism. it can.

  As described above, the light-emitting device of the present invention includes a light-emitting element such as a light-emitting diode in a dome-shaped wavelength conversion member in order to realize a light-emitting device such as a white light source, and emits light emitted from the light-emitting element. In a light emitting device that converts to a desired wavelength and emits light, light is emitted to the air such as the outer surface of the wavelength converting member or the outer surface of the transparent member when the light emitting element is covered with a transparent member. A cross-sectional shape obtained by cutting a surface by a surface to be light-distributed is a semi-elliptical shape having a focal point at two intersections between the surface and a circle circumscribing the light-emitting element, and normal lines at points on the semi-ellipse. And an angle formed by each of the focal points is in a range from a semi-ellipse to a semi-circle having an angle less than the total reflection angle of the member forming the light emitting surface.

  Therefore, even if the light emitting surface is a flat semi-elliptical to semicircular shape, while preventing total reflection due to a difference in refractive index between the wavelength conversion member and the transparent member and air on the light emitting surface, Compared with, for example, the above-mentioned bullet-shaped shape, the size can be reduced and the amount of radiation from the side surface can be reduced (by directing many of the normals of the light exit surface to the front direction, The amount of radiation increases) and the light extraction efficiency can be increased. Furthermore, since the distance between the wavelength conversion member and the light emitting element is close, it is possible to increase the density of the excitation light irradiated to the wavelength conversion member. The light can be emitted from the conversion member.

  In addition, as described above, the light-emitting device of the present invention includes the light-emitting element in a high-refractive-index transparent member having a property of transmitting light, and further forms a dome-shaped wavelength conversion member with a predetermined gap therebetween. Enclose.

  Therefore, by enclosing with a transparent member having a high refractive index, light emitted from the light emitting element can be taken out efficiently and the light emitting element can be protected.

  Furthermore, in the light emitting device of the present invention, as described above, the light emitting element is mounted on a substrate and sealed by the substrate and the transparent member, and the peripheral portion of the transparent member having a high refractive index is inclined. Cut (chamfer).

  Therefore, the inclined surface serves as a reflecting surface that reflects light emitted from the light emitting element to the side in the forward direction, so that the light use efficiency can be improved and the beam angle can be reduced.

  In the light-emitting device of the present invention, as described above, the transparent member has a two-layer structure including a dome-shaped outer shell and an inner member filled between the outer shell and the light-emitting element. The material is formed from a material having a relatively low refractive index compared to the outer shell.

  Therefore, due to the difference in refractive index, the light emitted from the light emitting element to the side (in the direction of the peripheral edge of the dome-shaped transparent member) is also front-facing (at the dome) at the interface between the inner member and the outer shell. Refracted in the direction of the ceiling), and enters the dome-shaped wavelength conversion member at an angle close to the vertical, so that the color shift can be further reduced, and the air layer in the gap from the air layer to the wavelength conversion member Total reflection at the interface can be prevented, and the light extraction efficiency can be further increased. In addition, the light-emitting element can be protected by employing an elastic gel or rubber for the inner member.

  Furthermore, the light emitting device of the present invention makes the thickness of the outer shell uniform as described above.

  Therefore, since the light path lengths when the light emitted from the light emitting element passes through the outer shell are substantially equal, the unevenness in luminance on the light emitting surface of the transparent member can be reduced.

  In addition, as described above, the light emitting device of the present invention forms a convex lens on the light extraction surface of the wavelength conversion member when viewed from the surface on which the light distribution is to be controlled.

  Therefore, light with higher center luminance can be emitted by the light condensing effect of the convex lens.

  Furthermore, in the light emitting device of the present invention, as described above, the phosphor concentration in the wavelength conversion member is relatively high on the light emitting element side and thin on the emission surface side of the wavelength conversion member. .

  Therefore, even if a convex lens is formed on the wavelength conversion member as described above, the wavelength conversion at the convex lens portion is slight, and most of the wavelength conversion is performed on the inner side of the dome-shaped wavelength conversion member (on the light emitting element side). ), Even if the convex lens portion is provided, the color of the light emitted from the peripheral portion of the dome-shaped wavelength conversion member and the light emitted from the ceiling portion (convex lens portion) The deviation can be reduced.

  Further, as described above, the light emitting device of the present invention transmits light from the light emitting element to the inner surface of the wavelength conversion member facing the transparent member, and reflects light generated by wavelength conversion by the wavelength conversion member. A wavelength filter is provided.

  Therefore, the light extraction efficiency can be further increased. In addition, the wavelength filter can selectively transmit only the light in the wavelength band that is efficiently converted by the phosphor, and the uniformity of the color of the converted light can be improved. Furthermore, in general, light emitted from a light emitting element is in a short wavelength band, and when the wavelength filter transmits the component, light in a long wavelength band that causes a temperature rise enters from the outside of the light emitting device and emits light. Reaching the element can be prevented and deterioration of the light emitting element can also be prevented.

  Furthermore, as described above, the light emitting device of the present invention has an antireflection film or a concavo-convex structure with a shorter interval than the desired wavelength on at least one light incident / exit surface of the wavelength conversion member and the transparent member. Provide.

  Therefore, the light extraction efficiency can be further improved.

  The white light source of the present invention uses the light emitting device as described above.

  Therefore, it is possible to improve the light extraction efficiency and realize a white light source that hardly causes color unevenness.

  Furthermore, in the illumination device of the present invention, as described above, since the light emitted from the white light source is diffused light, the light emitted from the light emitting surface is arranged on the light emitting surface side of the wavelength conversion member. An optical member for light control is provided.

  Therefore, by combining with an optical member such as a lens or a prism to control the light distribution at a narrow angle, the application of the lighting device can be expanded.

[Embodiment 1]
FIG. 1 is a cross-sectional view of a white light source 1 which is a light emitting device according to a first embodiment of the present invention, and FIG. 2 is a perspective view thereof. The white light source 1 is generally composed of a light emitting diode or the like, and emits light of a short wavelength such as blue or ultraviolet, a substrate 3 on which the light emitting element 2 is mounted, and the light emitting element 2. A sub-substrate 4 appropriately interposed between the light-emitting element 2 and the substrate 3 in accordance with the routing of the electrode pattern, the bonding method to the substrate 3, etc. The transparent member 5 that is hermetically sealed with, and is covered with a predetermined gap 6 outside the transparent member 5, and the light emitted from the light-emitting element 2 is converted into a desired wavelength of each white component. And a dome-shaped wavelength conversion member 7 that radiates.

  It should be noted that in the present embodiment, a transparent surface serving as a light emission surface to the air at a cut surface at a surface where the light emitted from the light emitting element 2 as shown in FIG. As shown in FIG. 2, the cross-sectional shape of the outer surface of the member 5 is formed into a semi-ellipse R having the focal points F1 and F2 at the two intersections between the circle L1 circumscribing the light-emitting element 2 and the surface to be controlled for light distribution. Further, the angle θ formed between the normal V at each point P on the semi-ellipse R and each of the focal points F1 and F2, as shown in FIG. 1, is the total reflection of the transparent member 5 that forms the light emitting surface. It is to be set in a range from the semi-ellipse R1 to the semi-circle R2 having an angle less than the angle. When the gap 6 is not provided (the transparent member 5 and the wavelength conversion member 7 are in close contact with each other), the outer surface of the wavelength conversion member 7 becomes a light emitting surface for air, and has the same shape. What is necessary is just to form.

  Here, the two focal points F1 and F2 have a light emitting surface 2a of the light emitting element 2 having a square shape as shown in FIG. 3A or a regular hexagon as shown in FIG. It becomes a corner portion on the diagonal line L2. On the other hand, when the light emitting element 2 is circular as shown in FIG. 3C, the two focal points F1 and F2 are on one diameter line L3. In the case of an irregular shape, it is on the cutting line L4 at the surface where the light distribution should be controlled.

  The transparent member 5 is made of a material having a high refractive index, such as silicone, that is transparent to the wavelength of light emitted from the light emitting element 2. When the refractive index n of the transparent member 5 is 1.53, for example, the angle θ becomes θ = 40.8 ° from sin θ = 1 / n. Therefore, the shape of the semi-ellipse R is defined in a range from the flat semi-ellipse R1 in a range where the outer surface of the transparent member 5 does not satisfy θ ≧ 40.8 ° to the semi-circle R2.

  FIG. 4 is a diagram for explaining how to obtain the locus of the semi-ellipse R1. First, as shown in FIG. 3, a radius X of the circumscribed circle L1 with respect to the light emitting element 2 is obtained. Next, a surface to be subjected to light distribution control is set, and an extension line (for example, an extension line of the diagonal line L2) of the light emitting surface of the light-emitting element 2 (upper surface in FIGS. If the distance to the intersection P2 with the semi-ellipse R1, that is, the major axis of the semi-ellipse R1, is 2A, the major axis 2A is obtained from A = X / sin θ. Subsequently, assuming that the distance to the intersection P between the normal V and the semi-ellipse R1 with respect to the center P0 of the circumscribed circle L1 where the angle θ is the largest, that is, the minor axis of the semi-ellipse R1 is 2B, B = X / tan θ From that, the minor axis 2B is obtained. For example, when X = 0.767 (mm), 2A = 2.164 (mm) and 2B = 1.664 (mm).

  Therefore, if the outer surface (semi-ellipse R) of the transparent member 5 is outside the semi-ellipse R1 composed of the major axis 2A and the minor axis 2B, total reflection does not occur. The locus of the semi-ellipse R may be set in the range from the semi-ellipse R1 to the semi-circle R2 so that the clearance can be satisfied. For example, in FIG. 2, the counter electrode of the light emitting element 2 is drawn on the sub-substrate 4, the major axis 2 </ b> A is set so as to be included up to the outer periphery of the bonding pad 3 a on the substrate 3 side, and the minor axis 2 </ b> B is the bonding wire 8. Set higher than the highest point.

  Note that the shape of the semi-ellipse R of the transparent member 5 determined in this way corresponds to the light emission direction 1a (in FIG. 1) with respect to the extension line of the light emission surface of the light emitting element 2 (upper surface in FIGS. 1 and 2). The tip of the semi-ellipse R may hang vertically with respect to the substrate 3 or may have an increased diameter as shown in FIG. It is preferable that the diameter is not reduced.

  In this way, the outer surface of the transparent member 5 serving as a light emitting surface for air is set in the range of the shape of the flat semi-ellipse R1 to the shape of the semi-circle R2, and the cross-sectional shape of the wavelength conversion member 7 is also set to the transparent member 5. The shape of the white light source compared to, for example, a shell-shaped shape of a semicircle R2 or more, while preventing total reflection due to the difference in refractive index between the transparent member 5 and air on the outer surface. 1 can be reduced in size, and the amount of radiation from the side surface is reduced (the amount of radiation in the front direction is increased by directing many of the normals of the light emitting surface in the front direction), and light is extracted. Efficiency can be increased and light distribution control can be performed. Furthermore, since the distance between the wavelength conversion member 7 and the light emitting element 2 is reduced, it is possible to increase the density of the excitation light irradiated to the wavelength conversion member 7, and as a result, there is little color shift with high central luminance. Light can be emitted from the wavelength conversion member 7.

  In addition, by encapsulating the light emitting element 2 with a transparent member 5 having a high refractive index that transmits light, the light emitted from the light emitting element 2 can be efficiently extracted and the light emitting element 2 can be protected. You can also.

[Embodiment 2]
FIG. 5 is a cross-sectional view of a white light source 11 which is a light emitting device according to the second embodiment of the present invention. The white light source 11 is similar to the white light source 1 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that in this white light source 11, the transparent member 15 is constituted by a dome-shaped outer shell 15 a and an inner member 15 b filled between the outer shell 15 a and the light emitting element 2. 15b is made of a material having a relatively low refractive index compared to the outer shell 15a and having elasticity, such as gel or rubber.

  In the white light source 11, the inner member 15 b is filled in the dome of the outer shell 15 a that is molded in advance, and the inner member 15 b is applied to the substrate 3 on which the light emitting element 2 is mounted. In the state in which the film is formed, they are combined, the peripheral edge of the outer shell 15a and the substrate 3 are bonded, and the inner member 15b is solidified, so that the light emitting element 2 is hermetically sealed in the outer shell 15a. It will be sealed.

  Thus, the transparent member 15 has a two-layer structure of the outer shell 15a having a dome shape and the inner member 15b filled between the outer shell 15a and the light emitting element 2, and the difference in refractive index between the two members is different. As shown in FIG. 5, the light emitted from the light emitting element 2 to the side (periphery of the dome-shaped transparent member 15) is also front-facing at the interface between the inner member 15b and the outer shell 15a. Is refracted in the direction (the ceiling direction of the dome) and is incident on the ceiling portion of the dome-shaped wavelength conversion member 7 at an angle close to the vertical, so that the color shift can be further reduced and the air layer in the gap 6 Therefore, it is possible to prevent total reflection at the interface from the light to the wavelength converting member 7 and to further increase the light extraction efficiency. Further, by employing the gel or rubber having elasticity for the inner member 15b, stress due to a difference in linear expansion coefficient between the light emitting element 2 and the transparent member 15 when repeating thermal expansion due to lighting and reduction due to extinction is repeated. Therefore, the light emitting element 2, the bonding wire 8, and the like can be protected.

[Embodiment 3]
FIG. 6 is a cross-sectional view of a white light source 21 that is a light emitting device according to a third embodiment of the present invention. The white light source 21 is similar to the white light source 11 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that in the white light source 21, the thickness of the outer shell 25a of the transparent member 25 is formed uniformly. The materials of the outer shell 25a and the inner member 25b are, for example, the same as those of the outer shell 15a and the inner member 15b of the transparent member 15, respectively.

  Accordingly, the light path lengths when the light emitted from the light emitting element 2 passes through the outer shell 25a having a high refractive index are substantially equal, so that uneven brightness on the light emitting surface of the transparent member 25 can be reduced.

[Embodiment 4]
FIG. 7 is a cross-sectional view of a white light source 31 which is a light emitting device according to the fourth embodiment of the present invention. The white light source 31 is similar to the white light source 11 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that in the white light source 31, the outer shell 35 a of the transparent member 35 has an inclined surface 35 c formed so that the peripheral edge is separated from the substrate 3. Further, in the white light source 31, a reflection increasing film 38 is formed on the inclined surface 35c. The inclination angle of the inclined surface 35 c is set to an angle that totally reflects light incident on the peripheral edge of the transparent member 35. The outer shell 35a can be molded by, for example, molds 39a and 39b as shown in FIG. 8, and the molded dome is filled with the inner member 35b and integrated with the substrate 3 on which the light emitting element 2 is mounted. The

  By thus cutting (chamfering) the peripheral edge of the high refractive index outer shell 35a into a slope, as shown in FIG. 7, the light emitted in the direction of the peripheral edge and cannot be used effectively is the slope 35c. Further, the reflection increasing film 38 is reflected forward, so that the light use efficiency can be improved and the beam angle can be reduced.

[Embodiment 5]
FIG. 9 is a cross-sectional view of white light sources 41a, 41b and 41c which are light emitting devices according to the fifth embodiment of the present invention. These white light sources 41a, 41b, and 41c are similar to the above-described white light source 1, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that in these white light sources 41a, 41b, and 41c, regions that overlap at least the light emitting element 2 on the light extraction surfaces of the wavelength conversion members 47a, 47b, and 47c when viewed from the surface on which the light distribution is to be controlled. Has protrusions 48a, 48b, and 48c protruding in the light emitting direction.

  In the white light source 41a of FIG. 9A, the convex portion 48a serving as a convex lens is formed only in the central portion overlapping the light emitting element 2. Moreover, in the white light source 41b of FIG.9 (b), the whole wavelength conversion member 47b is formed in the said convex part 48b used as a convex lens. On the other hand, in the white light source 41c shown in FIG. 9C, a convex portion 48c serving as a convex lens is formed at the central portion, and an uneven portion 48d for reducing Fresnel reflection is formed at the peripheral portion.

  Further, in the wavelength conversion members 47a, 47b, and 47c, the phosphor that converts the wavelength of incident light has a relatively high concentration on the light emitting element 2 side as shown in FIG. 47a, 47b, and 47c are dispersed continuously or stepwise so as to be thin on the exit surface side. FIG. 10A shows that the concentration of the phosphor is changed continuously, in FIG. 10B in a plurality of steps, and in FIG. 10C, in a single step. . For example, the wavelength conversion member of FIG. 10C can be formed by two-color molding, and the wavelength conversion member of FIG. 10B can be formed by multistage molding.

  With this configuration, the light from the light-emitting element 2 and the converted light generated by the wavelength conversion members 47a, 47b, and 47c are collected, and the center light intensity is particularly increased compared to the light intensity at the peripheral portion. It becomes possible. Further, when the light condensing is performed on the outer surfaces of the wavelength conversion members 47a, 47b, 47c in this way, the surface for controlling the light distribution is a light source as compared with the case where the light condensing is performed on the outer shell 15a of the transparent member 15. The light source is closer to the point light source when viewed from the surface where the light distribution is controlled, and it is easy to control. Moreover, the thickness of the whole wavelength conversion member 47c can be made thin by using a shape like FIG.9 (c).

  Furthermore, the wavelength conversion members 47a, 47b, and 47c are changed as described above by changing the phosphor concentration in the wavelength conversion members 47a, 47b, and 47c so that it is darker on the light emitting element 2 side and thinner on the emission surface side. Even if a convex lens is formed, the wavelength conversion at the convex lens portion is slight, and most of the wavelength conversion is performed uniformly over the entire inner surface (on the light emitting element 2 side) of the dome-shaped wavelength conversion member. It will be. Therefore, even if the convex lens portion is provided, light emitted from a thin peripheral portion where the convex lens is not provided in the dome-shaped wavelength conversion members 47a, 47b and 47c, and a thick ceiling where the convex lens is provided. The color shift from the light emitted from the portion can be reduced. More specifically, for example, when wavelength conversion is performed with a green + red phosphor or a yellow phosphor that is excited with a blue light emitting element and is uniformly dispersed, the thick portion is close to yellow. By providing the concentration distribution in the thickness direction as described above, it is possible to obtain a similar ratio of converted light even in portions having different thicknesses. In the most extreme example, if a wavelength conversion member made of a convex lens layer that does not include a phosphor is formed on the light-emitting element side, a constant-thickness layer in which the phosphor is uniformly dispersed is formed on the light-emitting element side. It is possible to eliminate color unevenness and efficiently collect the converted light and the light from the light emitting element 2 with the convex lens on the light extraction surface of the wavelength conversion member, and obtain a white light source with high central luminance. Is possible.

  In addition, since the light converted by the phosphor is emitted in the entire circumferential direction of the phosphor, the light from the phosphor located on the light extraction surface side is incident on the light extraction surface at a steep angle, While the amount of reflected light components increases, the light emitted from the phosphors can be obtained by dispersing many phosphors away from the light extraction surface on the light emitting element 2 side as described above. The light component incident in the direction perpendicular to the light extraction surface increases, the light component confined in the wavelength conversion members 47a, 47b, and 47c is reduced, and the light extraction of the wavelength conversion members 47a, 47b, and 47c is performed. It is also possible to improve efficiency.

[Embodiment 6]
FIG. 11 is a cross-sectional view of a white light source 51 that is a light emitting device according to a sixth embodiment of the present invention. The white light source 51 is similar to the white light source 11 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that in this white light source 51, the light incident on the wavelength conversion member 7 from the light emitting element 2 is transmitted as it is on the inner surface of the wavelength conversion member 7 facing the transparent member 15 as shown in FIG. In addition, a wavelength filter 58 that reflects the light that has been wavelength-converted by the wavelength conversion member 7 and returned to the light emitting element 2 side is formed.

The wavelength filter 58 is formed by alternately laminating SiO ₂ and TiO ₂ , for example, and the light-emitting element 2 such as the light-emitting diode has a wavelength band of a certain width as indicated by reference numeral α1 in FIG. When the light wavelength-converted by the wavelength conversion member 7 is separated from the wavelength band as indicated by reference numeral α2, the wavelength thereof is indicated by reference numeral α3. By setting the transmission characteristics of the wavelength filter 58 between the bands, the light from the light emitting element 2 can be transmitted as it is and the light returned to the light emitting element 2 side can be reflected as described above. .

  By comprising in this way, the said light extraction efficiency can be made still higher. In addition, the wavelength filter 58 can selectively transmit only light in the wavelength band that is efficiently converted by the phosphor, and can improve the uniformity of the color of the light after conversion. Furthermore, light emitted from the light emitting element 2 is generally in a short wavelength band, and when the wavelength filter 58 transmits the component, light in a long wavelength band that causes a temperature rise enters from the outside of the white light source 51. In addition, it is possible to prevent the light emitting element 2 from reaching the light emitting element 2 and to prevent the light emitting element 2 from deteriorating.

[Embodiment 7]
FIG. 14 is a cross-sectional view of a white light source 61 that is a light emitting device according to a seventh embodiment of the present invention. The white light source 61 is similar to the white light sources 51 and 31 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that in this white light source 61, at least one of the wavelength conversion member 7 and the transparent member 15 (the wavelength conversion member 7 in the example of FIG. 14) has a light incident / exit surface (light emission surface in FIG. 14). The antireflection structure 68 is provided.

Examples of the antireflection structure 68 include an antireflection film shown in FIG. 14 formed by alternately laminating SiO ₂ and TiO _2, and an uneven structure with an interval shorter than the conversion wavelength in the wavelength conversion member 7. When the antireflection structure 68 is not provided, a reflection loss of about 4% occurs at the interface between the wavelength conversion member 7 and the air. On the other hand, for example, in the case of an antireflection film, it is possible to suppress the internal reflectance to 1% or less in the visible region by appropriately designing the film. Further, by forming such an antireflection film at three interfaces including the outer surface of the transparent member 15 and the inner surface of the wavelength conversion member 7, it is possible to increase the light extraction efficiency by about 10% in total. become.

  On the other hand, when an uneven structure having an interval shorter than the wavelength of the transmitted light is used as the antireflection structure 68, the transmittance (light extraction efficiency) is reduced by reducing Fresnel reflection on the surface of the transmitted light. It becomes possible to improve. For example, when blue, green, and red visible light is used as the desired extraction light, these wavelengths include a visible light component of 400 to 700 nm, so that the unevenness interval is about 100 nm to 400 nm. At this time, the depth of the unevenness is preferably as deep as possible, but at least 100 nm or more is desirable.

This is equivalent to a gradual decrease in the refractive index on the surface side for the photons heading to the surface, making it difficult to reflect on the surface and improving the light extraction efficiency. For example, when the irregularities are formed by triangular tapered grooves as shown in FIG. 15 so that the periodic structure interval is sufficiently smaller than the wavelength, the irregularities are transmitted from the member having the refractive index n _{2 to} the member having the refractive index n _1. Then, the effective refractive index is the TE wave,

And for TM waves,

It becomes. However, a, b, as shown in Figure 15, the width of the member of the refractive index n ₁ and member of refractive index n ₂ at an arbitrary cutting plane in the range W1 to peak-to-valley of the uneven.

  By gradually changing the effective refractive index in this way, it becomes equivalent to the presence of a thin film layer having a refractive index intermediate between the respective refractive indexes on the surface, and reflection can be reduced.

[Embodiment 8]
FIG. 16 is a cross-sectional view of a lighting device 71 according to an eighth embodiment of the present invention. The illuminating device 71 can employ the white light sources 1, 11, 21, 31, 41a, 41b, 41c, 51, 61 described above (illustrated as the white light source 1 in FIG. 16). It should be noted that in this illumination device 71, the light emitted from the light emitting surface is distributed to the light emitting surface side of each of the white light sources 1, 11, 21, 31, 41a, 41b, 41c, 51, 61. The optical member 72 for controlling is arranged. Each white light source 1, 11, 21, 31, 41 a, 41 b, 41 c, 51, 61 is covered with an optical member 72 as shown in FIG. 16, and one or more are used in combination. Used as the lighting device 71.

  The optical member 72 is composed of a lens or a prism using a light-transmitting material such as acrylic or polycarbonate, for example, and instead of the optical member 72, a reflection plate 73 as shown in FIG. Light distribution control can be performed. The light emitted from each of the white light sources 1, 11, 21, 31, 41a, 41b, 41c, 51, 61 is diffused light, and its use range is limited as it is. The light sources 1, 11, 21, 31, 41 a, 41 b, 41 c, 51, 61 are combined with these optical members 71 and the reflecting plate 73, and are used by being controlled by a narrow-angle light distribution.

  Here, basically, the smaller the light source and the higher the concentration of light source brightness, the narrower light distribution can be achieved with a smaller optical member. On the other hand, wide-angle light distribution can often be realized relatively easily by appropriately setting the shape of the optical member. Therefore, as described above, the smaller the light source and the higher the concentration of the luminance of the light source, the better the light source from the viewpoint of light distribution control. By the way, in the case of each above-mentioned embodiment, each white light source 1,11,21,31,41a, 41b, 41c, 51,61 is flattened compared with the prior art etc. of Unexamined-Japanese-Patent No. 2005-57266, for example. Therefore, the distance between the light emitting surface of the apex portion P11 and the light emitting element 2 is small, and the luminance concentration of the light source is high, and the angle is narrower than that of a lens of the same size. Light distribution can be controlled, and the application of the lighting device 71 can be expanded.

  Further, in order to realize narrow-angle light distribution, it is necessary to design by providing a design reference point at a position with the maximum luminance (for example, the vertex portion P11). In each of the embodiments, the height H1 of the white light source 1, 11, 21, 31, 41a, 41b, 41c, 51, 61 is lower than the height H2 in the Japanese Patent Application Laid-Open No. 2005-57266. The overall height H3 of the optical system can be reduced, and the optical system, and hence the illumination device 71 can be reduced in thickness.

It is sectional drawing of the white light source which is the light-emitting device which concerns on the 1st Embodiment of this invention. FIG. 2 is a perspective view of FIG. 1. It is a figure for demonstrating the shape of a light emitting element. It is a figure for demonstrating the design method of the light-projection surface in this invention. It is sectional drawing of the white light source which is the light-emitting device which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the white light source which is a light-emitting device which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the white light source which is a light-emitting device which concerns on the 4th Embodiment of this invention. FIG. 8 is a cross-sectional view for explaining a method of molding a transparent member that includes a light emitting element in the white light source shown in FIG. 7. It is sectional drawing of the white light source which is a light-emitting device concerning the 5th Embodiment of this invention. In the white light source shown in FIG. 9, it is sectional drawing for demonstrating the structural example of a wavelength conversion member. It is sectional drawing of the white light source which is a light-emitting device concerning the 6th Embodiment of this invention. It is a figure for demonstrating the function of a wavelength filter in the white light source shown in FIG. 10 is a graph for explaining the characteristics of a wavelength filter in the white light source shown in FIG. 9. It is sectional drawing of the white light source which is a light-emitting device based on the 7th Embodiment of this invention. It is a figure for demonstrating the function of the fine unevenness | corrugation which is an antireflection structure in the white light source shown in FIG. It is sectional drawing of the illuminating device which concerns on the 8th Embodiment of this invention. It is sectional drawing of the illuminating device which concerns on the 8th Embodiment of this invention.

Explanation of symbols

1, 11, 21, 31, 41a, 41b, 41c, 51, 61 White light source 2 Light emitting element 3 Substrate 4 Sub-substrate 5, 15, 25, 35 Transparent member 6 Gap 7, 47a, 47b, 47c Wavelength converting member 15a, 25a, 35a Outer shells 15b, 25b, 35b Inner member 35c Slope 38 Reflection increasing films 39a, 39b Molds 48a, 48b, 48c Convex portion 58 Filter 68 Antireflection structure 71 Illumination device 72 Optical member 73 Reflector

Claims (11)

In a light-emitting device that includes a light-emitting element between a substrate and a dome-shaped wavelength conversion member , converts light emitted from the light-emitting element into a desired wavelength, and emits the light.
The light emission surface to the dome-shaped air is cut in a plane perpendicular to the substrate and the light emitted from the light-emitting element is to be light-distributed, and the cross-sectional shape is light emission from the cut surface. A semi-ellipse having a focal point at two intersections with a circle circumscribing the element, and the angle formed between the normal line at each point on the semi-ellipse and each focal point is the total reflection of the member forming the light emitting surface A light emitting device having a range from a semi-ellipse to a semi-circle having an angle less than an angle. The light emitting element is enclosed in a transparent member of the high have refractive index than air having a property of transmitting light, characterized in that it is further included in the wavelength converting member of the dome-shaped at a gap of predetermined distance The light emitting device according to claim 1.   The light-emitting element is mounted on a substrate and is sealed by the substrate and the transparent member, and the transparent member has an inclined surface formed so that a peripheral portion is separated from the substrate. Item 3. A light emitting device according to Item 2.   The transparent member includes a dome-shaped outer shell and an inner member filled between the outer shell and the light emitting element, and the inner member is a material having a relatively low refractive index compared to the outer shell. The light-emitting device according to claim 2 or 3, characterized by comprising:   The light emitting device according to claim 4, wherein the outer shell has a uniform thickness.   The light emitting device according to any one of claims 1 to 5, wherein the wavelength conversion member has a convex portion protruding at least in a region overlapping with the light emitting element in a light emitting direction.   The phosphor that converts the wavelength of incident light in the wavelength conversion member is continuously or stepwise so that the concentration thereof is relatively high on the light emitting element side and thin on the emission surface side of the wavelength conversion member. The light emitting device according to claim 6, wherein the light emitting device is dispersed.   The wavelength conversion member includes a wavelength filter that transmits light from a light emitting element and reflects light generated by wavelength conversion by the wavelength conversion member on an inner surface facing the transparent member. The light-emitting device of any one of 2-7.   The light emitting device according to claim 1, further comprising an antireflection structure on at least one light incident / exit surface of the wavelength conversion member and the transparent member.   A white light source using the light-emitting device according to claim 1.   The white light source according to claim 10, wherein an optical member for controlling light distribution of the light emitted from the light emitting surface is disposed on the light emitting surface side of the wavelength conversion member. apparatus.