JP5221797B2 - Light source for illumination - Google Patents

Description

  The present invention relates to an illumination light source using a semiconductor light emitting element, and more particularly to a technique for improving light distribution characteristics.

In recent years, as an alternative to an incandescent bulb, a bulb-shaped illumination light source using a semiconductor light emitting element such as an LED (Light Emitting Diode) is becoming widespread.
Since such an illumination light source uses an LED having a narrow irradiation angle (light distribution angle) as a light source, it has a problem that light distribution characteristics are narrower than that of an incandescent bulb. Therefore, as illustrated in FIG. 7, in the illumination light source 900 described in Patent Document 1, the base 901 includes a first base portion 902 and a reverse cone from a part of the front surface of the first base portion 902. The first LED 904 is disposed on the front surface of the first base portion 902, and the second LED 905 is disposed on the front surface of the second base portion 903. When the second base portion 903 is projected from the front onto the first base portion 902, the light emitting surface of the first LED 904 exists within the projection area, and the side surface of the second base portion 903 is the light reflecting surface. The configuration of 906 is adopted. With this configuration, the light emitted from the first LED 904 is reflected obliquely backward by the light reflecting surface 906 to compensate for the narrow irradiation angle of the LED, thereby realizing relatively good light distribution characteristics.

JP 2010-86946 A Special table 2008-547175 gazette

  However, in the case of the illumination light source 900 described in Patent Document 1, the front surface of the first base portion 902 and the front surface of the second base portion 903 serve as LED mounting surfaces, and LEDs 904 and 905 are separately provided on these two mounting surfaces. Therefore, the assembly work is complicated compared to the case where there is only one LED mounting surface. Further, if the base 901 has a complicated shape including the first base portion 902 and the second base portion 903, the cost of the base 901 is increased.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an illumination light source having good light distribution characteristics and easy assembly work.

  In order to achieve the above object, an illumination light source according to the present invention includes a plurality of semiconductor light emitting elements arranged in a ring shape on a main surface of a base, and an incident surface facing a light emitting portion of each of the semiconductor light emitting elements. The light guide is formed so as to face the incident surface, and is formed to extend from an annular first boundary surface portion and an end of the first boundary surface portion. A second boundary surface portion, wherein the first boundary surface portion transmits a part of the light incident inside from the incident surface to the outside front and the other part to the second boundary. The second boundary surface portion reflects a part of the reflected light from the first boundary surface portion obliquely backward to avoid the main surface of the base.

  The plurality of semiconductor light emitting elements are arranged in an annular shape, and the light guide has a cylindrical portion and a flare portion extending radially outward from one end of the cylindrical portion. The other end portion of the cylindrical portion faces the light emitting portion of each semiconductor light emitting element to form the incident surface, and the flare portion is an outer periphery from the inner peripheral edge portion to the outer peripheral edge portion. A cross section of the surface cut by a plane passing through the axial center of the cylindrical portion has a mountain shape that is convexly curved toward an extension direction of the axial direction of the cylindrical portion, and the inner peripheral edge An outer surface portion extending from the top portion to the top of the chevron is configured as the first boundary surface, and an outer surface portion extending from the top portion to the outer peripheral edge portion is configured as the second boundary surface portion. To do.

  Further, the base, a circuit unit that converts power supplied through the base to power for causing the semiconductor light emitting element to emit light, and the circuit unit is included, and the base and the base are connected. And a globe having diffusion permeability and being attached to the housing in a state of covering the light guide, and being reflected at the second boundary surface portion, The glove inner peripheral surface portion where the light traveling obliquely rearward to avoid the main surface reaches is subjected to a diffusion treatment that makes the diffusivity higher than other inner peripheral surface portions.

In this case, the diffusion treatment is performed by forming a plurality of first hemispherical pits uniformly formed on the inner circumferential surface of the globe and a plurality of pits on the inner surfaces of the first dents. The second depression is smaller than the second depression.
Further, the casing has a tapered cylindrical shape, the base and the globe are attached to the large diameter side of the casing, and the base is attached to the small diameter side, respectively, in the central axis direction of the tapered cylinder The base end of the globe is closer to the base than the flare part of the light guide.

  Since the illumination light source according to the present invention has a configuration in which a plurality of semiconductor light emitting elements are arranged on the main surface of the base, it is easy to mount the semiconductor light emitting elements on the base, and the assembly work of the illumination light source is simple It is. In addition, a part of the light emitted from the semiconductor light emitting element arranged in an annular shape and incident from the incident surface to the inside is transmitted to the outside front and reflected to the oblique rear avoiding the main surface of the base. Since the body is provided, the light distribution characteristic of the illumination light source is good while using the semiconductor light emitting element having a narrow light distribution angle.

It is sectional drawing which shows schematic structure of the LED lamp which concerns on embodiment. It is a top view which shows the LED module which comprises the said LED lamp. It is the A section enlarged view in FIG. It is the A section enlarged view in Drawing 1, and is a figure for explaining an example of a course of light which entered a light guide from LED. It is a light distribution curve figure for demonstrating the light distribution characteristic of the light source for illumination. It is an expanded end view showing the diffusion processing part formed in the glove opening part vicinity. It is sectional drawing which shows the conventional light source for illumination.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an illumination light source according to the present invention will be described below with reference to the drawings, taking a bulb-shaped LED lamp as an example.
FIG. 1 is a cross-sectional view showing a schematic configuration of a light bulb-shaped LED lamp 10 (hereinafter simply referred to as “LED lamp 10”) having LEDs as semiconductor light emitting elements. Here, the “bulb shape” is an alternative light source to a general incandescent light bulb, which has a cap and a circuit unit for lighting a light source (LED) of the same standard as an incandescent light bulb, It can be attached to a lighting fixture for use.
<Overall configuration>
As shown in FIG. 1, the LED lamp 10 includes an LED module 12, a base 14 on which the LED module 12 is mounted, a globe 16 that covers the LED module 12, and a circuit unit 18 that lights the LED module 12. The circuit holder 20 that houses the circuit unit 18, the case 22 that is a casing that covers the circuit holder 20, the base 24 that is electrically connected to the circuit unit 18, and the light emitted from the LED module 12 is received and received. And a light guide 26 that guides and emits the light as described later.

Here, in FIG. 1, the alternate long and short dash line drawn in the vertical direction of the paper indicates the lamp axis J of the LED lamp 10, the upper side of the paper is the front of the LED lamp 10, and the lower side of the paper is the rear of the LED lamp 10. Suppose there is. Also, when a certain member constituting the LED lamp 10 or a certain portion of the member is used as a reference, the direction along the lamp axis J, the upper side of the paper or the lower side of the member or the site is the front, and the lower side of the paper is the rear.
<Configuration of each part>
(1) Semiconductor Light Emitting Module FIG. 2 is a plan view showing the LED module 12 that is a semiconductor light emitting module. As shown in FIG. 2, the LED module 12 is mounted so as to cover the mounting substrate 28, a plurality (16 in this example) of LEDs 30 as light sources mounted on the mounting substrate 28, and the LEDs 30. And a sealing body 32 provided on the substrate 28.

  The mounting substrate 28 includes a substantially annular element mounting portion 34 and a tongue piece portion 36 extending from one place on the inner periphery of the element mounting portion 34 toward the center of the ring. A connector 40 to which the wiring 38 (FIG. 1) of the circuit unit 18 is connected is provided on the rear surface of the tongue piece 36. By connecting the wiring 38 to the connector 40, the LED module 12 and the circuit unit 18 are connected. Electrically connected.

The plurality of LEDs 30 are mounted in an annular shape on the front surface of the element mounting portion 34.
Each of the LEDs 30 is individually sealed by a sealing body 32 having a substantially rectangular parallelepiped shape. Therefore, the number of the sealing bodies 32 is 16 in total.
The sealing body 32 is mainly made of a translucent material, but when it is necessary to convert the wavelength of the light emitted from the LED 30 to a predetermined wavelength, the wavelength of the light is converted into the translucent material. Wavelength conversion material is mixed. As the translucent material, for example, a silicone resin can be used, and as the wavelength conversion material, for example, phosphor particles can be used.

  In this Embodiment, LED30 which radiate | emits blue light, and the sealing body 32 formed with the translucent material with which the fluorescent substance particle | grains which wavelength-convert blue light into yellow light were mixed are employ | adopted. Part of the blue light emitted from the LED 30 is converted into yellow light by the sealing body 32, and white light generated by mixing the yellow light and the blue light that has not been converted is emitted from the LED module 12. .

Further, the LED module 12 may be, for example, a combination of ultraviolet light emitting semiconductor light emitting elements and respective color phosphor particles that emit light in three primary colors (red, green, and blue). Further, a material containing a substance that absorbs light of a certain wavelength and emits light of a wavelength different from the absorbed light, such as a semiconductor, a metal complex, an organic dye, or a pigment, may be used as the wavelength conversion material.
(2) Base Returning to FIG. 1, the base 14 has, for example, a substantially cylindrical shape, and is arranged in a posture in which the central axis (cylinder axis) coincides with the lamp axis J. Therefore, the hollow portion 42 of the base 14 penetrates in the front-rear direction, and the front surface 44 and the rear surface 46 of the base 14 are both substantially annular planes. And the LED module 12 is mounted in the front surface 44 of the base 14, and, as a result, each LED 30 is in a state of being arranged in a plane in an annular shape with its main emission direction facing forward. Thus, since all the LEDs 30 are arranged in a plane on the front surface 44 of the base 14, the LEDs 30 can be easily mounted on the base 14, and the assembly work of the illumination light source is simple. The LED module 12 can be mounted on the base 14 by, for example, screwing, bonding, engagement, or the like.

The front surface 44 is not limited to a substantially annular shape, and may have any shape. Further, the front surface 44 does not necessarily need to be entirely flat as long as the LEDs 30 can be arranged in a plane.
The base 14 is made of, for example, a metal material. As the metal material, for example, Al, Ag, Au, Ni, Rh, Pd, Cu, or an alloy made of two or more thereof, or an alloy of Cu, particularly Ag, is used. Alloys are conceivable. Since such a metal material has good thermal conductivity, heat generated in the LED module 12 can be efficiently conducted to the case 22.

The LED lamp 10 is lightweight because the base 14 has a hollow portion 42. Moreover, since a part of the circuit unit 18 is disposed in the hollow portion 42 and in the globe 16 through the hollow portion 42, the size is small.
(3) Globe In this embodiment, the globe 16 has a shape imitating a bulb of an A-type bulb that is a general bulb shape, and the opening side end of the globe 16 is fixed to the base 14 and the case 22. Yes. The envelope of the LED lamp 10 includes a globe 16 and a case 22. The shape of the globe 16 is not limited to the shape imitating a bulb of an A-type bulb, and may be any shape.

  The globe 16 is made of a translucent material such as a synthetic resin material or a glass material. The inner surface of the globe 16 is subjected to a diffusion treatment for diffusing the light emitted from the LED module 12, for example, a wiping coating of silica or other fine particles or a white pigment coating. That is, the globe 16 has diffuse permeability. Light incident on the inner surface of the globe 16 passes through the globe 16 and is extracted to the outside of the globe 16. In order to obtain diffuse permeability, the globe 16 itself may be formed of a milky white material.

(4) Circuit Unit The circuit unit 18 is for lighting the LED 30 and includes a circuit board 48 and various electronic components 50 and 52 mounted on the circuit board 48. In the drawings, only some electronic components are denoted by reference numerals. The circuit unit 18 is accommodated in the circuit holder 20 and is fixed to the circuit holder 20 by, for example, screwing, bonding, engagement, or the like.

  The circuit board 48 is arranged in a posture in which its main surface is parallel to the lamp axis J. In this way, the circuit unit 18 can be stored in the circuit holder 20 more compactly. The circuit unit 18 is arranged such that the heat-sensitive electronic component 50 is located on the rear side far from the LED module 12 and the heat-resistant electronic component 52 is located on the front side close to the LED module 12. In this way, the heat-sensitive electronic component 52 is unlikely to be thermally destroyed by the heat generated in the LED module 12.

The circuit unit 18 and the base 24 are electrically connected by electrical wires 54 and 56. The electrical wiring 54 is connected to the shell portion 60 of the base 24 through a through hole 58 provided in the circuit holder 20. Further, the electrical wiring 56 is connected to the eyelet part 62 of the base 24 through the rear side opening of the circuit holder 20.
A part of the circuit unit 18 is disposed in the hollow portion 42 of the base 14 and in the globe 16. By doing in this way, the space for accommodating the circuit unit 18 in the back side rather than the base 14 can be made small. Therefore, the distance between the base 14 and the base 24 can be reduced, and the diameter of the case 22 can be reduced, which is advantageous for downsizing the LED lamp 10.

(5) Circuit holder The circuit holder 20 has, for example, a substantially cylindrical shape that is open on both sides, and includes a large diameter portion 64 and a small diameter portion 66. Most of the circuit unit 18 is accommodated in the large-diameter portion 64 located on the front side. On the other hand, the base 24 is fitted on the small-diameter portion 66 located on the rear side, and thereby the rear-side opening of the circuit holder 20 is closed. The circuit holder 20 is preferably formed of an insulating material such as resin, for example.

  A part of the large diameter portion 64 of the circuit holder 20 enters the hollow portion 42 of the base 14, and a part of the circuit unit is accommodated in the hollow portion 42 of the base 14 while being accommodated in the circuit holder 20. Has been placed. The circuit holder 20 and the base 14 are not in contact with each other, and a gap is provided between them. In other words, a gap is provided between the outer surface (outer peripheral surface) of the circuit holder 20 and the inner surface of the hollow portion 42 of the base 14 (inner peripheral surface of the base 14). The width of the gap in the direction orthogonal to the lamp axis J is substantially uniform over the entire outer periphery of the circuit holder 20. Thus, by providing a gap between the circuit holder 20 and the base 14, it is difficult for heat to propagate from the base 14 to the circuit holder 20. Therefore, the circuit holder 20 is unlikely to become high temperature, and the circuit unit 18 is difficult to be thermally destroyed.

As described above, since a gap is provided between the circuit holder 20 and the base 14, air easily convects in the envelope configured by the globe 16 and the case 22. That is, since air can circulate through the gap between the space in the globe 16 and the space on the rear side of the base 14 in the case 22, there are local high-temperature locations in the envelope. Not likely to occur.
(6) Case The case 22 has, for example, a tapered cylindrical shape whose diameter is reduced from the front to the rear. The base 14 and the opening side end of the globe 16 are accommodated in the front side end (large diameter side end) 68 of the case 22, and the case 22, the base 14 and the globe 16 are, for example, The space 70 surrounded by is fixed integrally by pouring an adhesive or the like.

  The outer peripheral edge of the rear side end of the base 14 has a tapered shape in accordance with the shape of the inner peripheral surface of the case 22. Since the tapered surface is in surface contact with the inner peripheral surface of the case 22, the heat propagated from the LED module 12 to the base 14 is further easily conducted to the case 22. The heat generated in the LED 30 is conducted to the base 24 mainly through the base 14 and the case 22 and further through the small diameter portion 66 of the circuit holder 20 and is radiated from the base 24 to the lighting fixture (not shown). .

Further, since almost no gap is generated by the surface contact, it is possible to prevent the light propagating through the globe 16 from leaking into the case 22 through the gap as much as possible.
The case 22 is made of, for example, a metal material. As the metal material, for example, Al, Ag, Au, Ni, Rh, Pd, Cu, or an alloy composed of two or more thereof, or an alloy of Cu, particularly an alloy of Ag. And so on. Since such a metal material has good thermal conductivity, the heat transmitted to the case 22 can be efficiently transmitted to the base 24 side.

(7) Base The base 24 is a member for receiving electric power from the socket of the lighting fixture when the LED lamp 10 is attached to the lighting fixture and turned on. The type of the base 24 is not particularly limited, but an E26 base that is an Edison type is used in the present embodiment. The base 24 includes a shell portion 60 having a substantially cylindrical shape and an outer peripheral surface being a male screw, and an eyelet portion 62 attached to the shell portion 60 via an insulating portion 72. An insulating member 74 is interposed between the shell portion 60 and the case 22.

(8) Light Guide As shown in FIG. 1, the light guide 26 has a substantially “L” -shaped cross section (a cross section cut along a plane including the lamp axis J) and is generally annular (this In the example, it has an annular shape). The light guide 26 is made of polycarbonate. The light guide 26 is not limited to polycarbonate, and may be formed of other light transmissive materials. The light guide 26 includes a cylindrical portion 78 and a flare portion (flange portion) 82 extending outward in the radial direction from one end portion of the cylindrical portion 78.

  The light guide 26 is attached to the circuit holder 20 via a cap 76 (bottomed cylindrical shape) that is integrally formed with the light guide 26. In the attached state, the annular light guide 26 has an annular center located on the lamp axis J. A slit 77 is formed in a part of the cylindrical portion of the lid member 76, and the tongue piece 36 of the mounting board 28 extends in the direction of the lamp axis J through the slit 77.

FIG. 3 is an enlarged view of part A in FIG. 1 and shows the light guide 26 and the vicinity thereof.
As described above, the light guide 26 has the cylindrical portion 78 having the lamp shaft J (FIG. 1) and the shaft center in common. The other end portion 80 of the cylindrical portion 78 (a surface facing the light emitting surface of the LED 30) 80 is an incident surface 80 that receives the light emitted from the LED 30 into the light guide 26.
Since the LED 30 exhibits a Lambertian characteristic in which the angle dependency of the light intensity is about full width at half maximum of 120 °, the width of the incident surface 80 and the distance from the LED 30 are the light emitted from the LED 30 that spreads at a light distribution angle α = 120 °. It is preferable to set the relationship so that all of the light enters the incident surface 80.

As described above, the light guide 26 also has a flare portion (flange portion) 82 extending (projecting) from the opposite side of the incident surface (end surface) 80 of the cylindrical portion 78 to the outside of the cylinder. .
The flare portion 82 has an outer surface extending from the inner peripheral edge portion to the outer peripheral edge portion, and a cross section (cross section) cut along a plane passing through the axial center of the cylindrical portion 78 is an extension of the cylindrical portion 78 in the axial direction. It has a mountain shape that is curved in a convex shape toward the direction.

In the cross section, the flare portion 82 is divided into an inner portion 86 and an outer portion 88 in a direction perpendicular to the lamp axis J with the mountain-shaped top portion 84 as a boundary.
According to the light guide body 26 configured as described above, the light emitted from the LED 30 and incident from the incident surface 80 is emitted not only in front of the LED lamp 10 but also to the side and rear. This will be described with reference to FIG.

Light L1 emitted straight forward from the LED 30 (parallel to the lamp axis J) enters the light guide 26 from the incident surface 80, and proceeds forward as it is.
In accordance with Snell's law, the light that has traveled is a boundary surface with the outside of the light guide 26 in the inner portion 86 (in other words, the outer surface from the inner peripheral edge of the flare portion 82 to the peak 84 in the shape of a mountain, hereinafter “ 1 ”), a part of the light is transmitted and emitted to the outside of the light guide 26 (L2). The other part is reflected and travels in the direction away from the lamp axis J inside the light guide 26 (L3).

  The light (L3) traveling in the direction away from the lamp axis J passes through the boundary surface with the outside of the light guide 26 in the outer portion 88 (in other words, the outer peripheral edge portion from the mountain-shaped top portion 84 of the flare portion 82). (Hereinafter referred to as “second boundary surface 92”), a part thereof is transmitted to the outside of the annular light guide 26 according to Snell's law (L4). The other part is reflected backward and travels inside (L5), and is emitted obliquely behind the light guide 26 (L6).

Here, the first boundary surface 90 has an annular shape (in the present example, an annular shape) when viewed from the direction of the lamp axis J, and is formed extending from the outer peripheral edge of the first boundary surface 90. The second boundary surface 92 also has an annular shape (in this example, an annular shape).
Even if the light guide does not have the cylindrical portion 78 (that is, the light guide having only the flare portion 82), the light incident on the light guide is emitted obliquely behind the light guide. In this case, since the emission position is too close to the base 14, the emitted light (for example, light corresponding to L 6) is blocked by the base 14 and is not emitted to the rear of the LED lamp. That is, the cylindrical portion 78 is provided so as not to be blocked by the base as long as light emitted obliquely backward from the light guide is possible. On the other hand, when the overall length of the cylindrical portion 78 is made longer, the light blocked by the base among the light emitted obliquely rearward from the light guide is further reduced. The light is emitted from the cylindrical portion 78 to the outside of the light guide 26 before reaching the flare portion 82, and the amount of light entering the flare portion 82 is reduced. As a result, the light is obliquely rearward from the light guide. The amount of light emitted to the light source itself decreases. The total length of the cylindrical portion 78 is appropriately set in consideration of this point.

In order to emit light obliquely backward without being blocked by the base 14, the outer diameter of the flare portion 82 is preferably as large as possible, but in this example, an annular base The outer diameter is less than 14 (less than the opening diameter of the globe 16). This is because the globe 16 cannot be attached to the base 14 if the outer diameter of the base 14 is larger than the outer diameter.
And the light radiate | emitted from the light guide 26 will be radiate | emitted from the LED lamp 10, after being diffused by the glove | globe 16 which has transmission diffusivity.

  As described above, the light with the highest luminance (main emission light) emitted straight forward from the LED 30 is guided by the light guide 26, and is illustrated in three directions (L2, L4, L6) on the front, side, and diagonally rear sides. However, since the light is emitted from the LED 30 with a spread of a light distribution angle of 120 °, the light from the light guide 26 is not only in these three directions but also in the three directions. Needless to say, the light is emitted.

In the above example, the front surface of the flare portion 82 is a smoothly curved surface. However, the present invention is not limited to this, and it may be a continuous plane (preferably a continuous body of minute planes) along the curved surface. Alternatively, a combination of a curved surface and a plane may be used.
[Light distribution characteristics of illumination light source]
Next, the reason why the light distribution characteristic of the LED lamp 10 that is an illumination light source is good will be described in detail. FIG. 5 is a light distribution curve diagram for explaining the light distribution characteristics of the illumination light source. As shown in FIG. 5, the light distribution curve diagram shows the magnitude of the luminous intensity with respect to each direction of 360 ° including the front-rear direction of the LED lamp 10, and the front of the LED lamp 10 in the lamp axis J direction is 0 °. The scale is engraved at intervals of 10 ° clockwise and counterclockwise with the rear in the axis J direction being 180 °. A scale in the radial direction of the light distribution curve diagram represents the light intensity, and the light intensity is represented by a relative size with a maximum value of 1 in each light distribution curve.

In FIG. 5, the light distribution curve A of the incandescent light bulb is shown using a one-dot chain line, the light distribution curve B of the illumination light source 900 of Patent Document 1 is shown using a broken line, and the LED according to the present embodiment is shown using a solid line. A light distribution curve C of the lamp 10 is shown.
The light distribution characteristics were evaluated based on the light distribution angle. The light distribution angle refers to the size of an angle range in which a light intensity equal to or more than half of the maximum light intensity value in the illumination light source is emitted. In the case of the light distribution curve shown in FIG. 5, the magnitude of the angle range in which the luminous intensity is 0.5 or more.

  As can be seen from FIG. 5, the light distribution angle of the incandescent light bulb is about 315 °, the light distribution angle of the illumination light source 900 of Patent Document 1 is about 165 °, and the light distribution angle of the LED lamp 10 according to the present embodiment. The light angle is about 270 °. Thus, the LED lamp 10 has a light distribution angle wider than that of the illumination light source 900 and a light distribution angle closer to that of the incandescent light bulb. Therefore, it can be said that the LED lamp 10 has a light distribution characteristic better than that of the illumination light source 900 and has a light distribution characteristic approximate to an incandescent lamp.

As described above, the present invention has been described based on the embodiment. However, the present invention is not limited to the above-described form, and for example, the following form may be adopted.
(1) In the above-described embodiment, an LED is used as a semiconductor light emitting element. However, the present invention is not limited to this. For example, an LD (laser diode) or an EL element (electric luminescence element) may be used.
(2) In the above embodiment, the LEDs 30 are arranged in an annular shape. However, the present invention is not limited to this, and the LEDs 30 are arranged in another annular shape, for example, a triangular shape, a quadrangular shape, a pentagon or more polygonal shape, or an elliptical shape. It doesn't matter.
(3) In the above embodiment, the globe 16 has been subjected to the diffusion treatment as described above. Further, the inner peripheral surface portion near the opening of the globe 16 has an inner portion other than the inner peripheral surface portion. A diffusion process as shown in FIG. 6 in which the diffusibility is higher than that of the peripheral surface portion may be performed.

FIG. 6 is an end view of the vicinity of the inner peripheral surface in the vicinity of the opening of the globe 16, showing only the cut surface, and is an end view cut along a plane including the lamp axis J.
A hemispherical first recess 16B having a radius R (for example, R = 40 [μm]) is uniformly formed in the vicinity of the opening of the inner peripheral surface 16A of the globe 16 and the first recess 16B. A hemispherical second depression 16C having a radius r (for example, r = 5 [μm]) smaller than that of the first depression 16B is uniformly formed on each inner peripheral surface.

In this way, by forming the diffusion processing part 94 having a double recess structure in which a smaller recess (dimple) is uniformly formed in each uniformly formed minute recess (dimple). The light diffusibility is further improved as compared with the case of a single depression structure.
In the globe 16, the region where the diffusion processing unit 94 is formed is a range exposed from the case 22 that is a housing, and is preferably a range (region) where the reflected light from the second boundary surface portion 92 reaches. This is because the light emitted backward from the light guide 26 is diffused by the globe 16 (diffusion processing unit 94 thereof) to further expand the light distribution range backward.

Here, the radius of the first recess 16B is preferably in the range of R = 20 [μm] to 40 [μm], and the radius of the second recess is. The range of r = 2 [μm] to 8 [μm] is preferable.
The reason why the double recess structure is not diffused throughout the globe 16 is as follows. That is, the loss of light passing therethrough increases as the area having a higher diffusibility treatment is applied. Therefore, in consideration of the balance between diffusibility and light loss, especially in places where importance is placed on diffusivity, the diffusion process of the above double recess structure is performed, and it is not desired to cause light loss as much as possible. The reason for this is to perform a process that makes the diffusibility not excessive and appropriate.
(4) It is needless to say that the cap-shaped lid member 76 (FIG. 1) is not limited to the shape shown in the figure, and may be any shape that does not block the path of light emitted from the light guide 26 as much as possible. I do not care.
(5) In the above embodiment, the circuit holder 20 is provided in the case 22 and the circuit unit 18 is attached to the circuit holder 20. However, the circuit holder 20 is not limited to this, and the circuit unit is It may be attached to the base or the lid member 76.

  The present invention can be widely used in general lighting.

10 LED lamp 14 base 26 light guide 30 LED
44 Front 90 First interface 92 Second interface

Claims (1)

A base having a through-hole penetrating in a direction orthogonal to the main surface;
A plurality of semiconductor light emitting devices arranged in a ring shape on the main surface of the base, along the periphery of the through hole,
A circuit unit for causing the plurality of semiconductor light emitting elements to emit light;
An E-type base electrically connected to the circuit unit;
With
The circuit unit includes a circuit board and a plurality of electronic components mounted on one main surface of the circuit board,
A part of the circuit board of the circuit unit is disposed in the through hole,
When the axis of the base and the virtual axis formed by extending the same are used as the lamp axis,
The lamp shaft passes through the through hole, the main surface of the circuit board is parallel to the lamp shaft, and the circuit board has the other main surface on which no electronic component is mounted. It is arranged shifted from the lamp axis in a direction close to the inner peripheral surface of the hole,
An illumination light source, wherein one end of the circuit unit enters a hollow portion of the E-type base .

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