WO2013007814A2

WO2013007814A2 - Light-emitting diode lamp and lighting fixture

Info

Publication number: WO2013007814A2
Application number: PCT/EP2012/063776
Authority: WO
Inventors: Takahiro Akuta; Hiromi MURAMATSU; Keizo OISHI; Tatsuya Suzuki
Original assignee: Osram Ag
Priority date: 2011-07-14
Filing date: 2012-07-13
Publication date: 2013-01-17
Also published as: JP2013020911A; WO2013007814A3; JP5840406B2

Abstract

Problem. To provide a light-emitting diode lamp (20) with which it is possible to obtain a broader light distribution and light emission intensity in the length direction of the lamp, and with which heat can be dissipated efficiently and which therefore has a longer operating life. Means of overcoming the problems. A light-emitting diode lamp (20) is provided with a light-emitting diode unit (10) in which light-emitting diodes (11) are mounted on the side surfaces of a prismatic or cylindrical support member (13), and a housing (24) having a glass cover which envelops the light emitting surface of the abovementioned light-emitting diode unit (10) and which is arranged inside the light-emitting diode unit (10), and in which the height of the abovementioned light-emitting diode unit (10) in the axial direction of the support member (13) is a length which is between 1.5 times and 3.5 times the diameter of the circumcircle of the abovementioned support member (13).

Description

Light-emitting diode lamp and lighting fixture [Technical field]

[0001]

The present invention relates for example to LED (light- emitting diode element) bulbs for street lighting. In particular the present invention aims to obtain an LED bulb having a broad distribution of light similar to that of HID lamps (High Intensity Discharge lamps) used for street ligh^¬ ting and for security lighting.

[Background art]

[0002]

(1) Conventional HID lamp:

A. The emitted luminous flux is large and broad, and can illuminate a long distance, and these lamps are therefore used widely in outdoor applications such as street lighting and security lighting. Further, they are used in both base- down and base-up fixtures.

B. Power consumption is high and operating life is short (approximately 10,000 hours).

C. Light emission is through mercury discharge, and so it takes time for the mercury in the light-emitting tube to va- porize and for the brightness to stabilize.

[0003]

(2) Bulb-shaped LED:

A. Good light directionality, suitable for illuminating in a fixed direction, such as improving directly-downward illu- mination intensity in the downward direction (Patent litera^¬ ture article 1: Japanese Patent Kokai 2009-4130).

In this case, it is sufficient to install a few lamps, the amount of heat generated by the LED itself is low, and an operating life that is long compared with discharge lamps such as HID lamps, approximately 40,000 hours, can be main^¬ tained .

B. Lamps such as the following have been devised as LED lamps to replace conventional HID lamps for outdoor use.

Compatibility with conventional discharge lamps is achieved easily by filling a glass bulb with an inert gas and sealing it, and then fitting a screw-shaped cap, in the same way as with a conventional discharge lamp, while at the same time the radiation angle of the LED light is extended by provid^¬ ing a concave mirror behind the LED (Patent literature arti^¬ cle 2: Japanese Patent Kokai 1987-124781).

[Prior art literature]

[Patent literature]

[0004]

[Patent literature article 1] Japanese Patent Kokai

2009-4130

[Patent literature article 2] Japanese Patent Kokai 1987-124781

[Patent literature article 3] Japanese Patent Kokai

2010-55993

[Patent literature article 4] Japanese Patent Kokai 2010-182796

[Summary of the invention]

[Problems to be resolved by the invention]

[0005]

A. In street lighting and security lighting fixtures which are in widespread use, in order to illuminate outdoors broadly and for a long distance, as with conventional HID lamps, by exchanging only the lighting device and using the reflector plate and lamp holder without modification, the light distribution and light emission intensity must not in practical terms be inferior to those of an HID lamp.

B. If the light distribution is not oriented, but the light from the light-emitting diodes 11 is distributed in approxi- mately all directions then the lamp is not only applicable to street lights having substantially horizontal lights, which predominantly illuminate a lower surface, but also to base-down and base-up fixtures.

C. With the LED lamp in patent literature article 2 it is difficult to obtain a light distribution and light emission intensity that are comparable to an HID lamp, and it is nec^¬ essary to increase the number of LEDs significantly and to orient the LED light in all directions, as with an HID lamp. D. By grouping a large number of LEDs together the inside of the lamp becomes hot, the LEDs deteriorate rapidly, and it is difficult to maintain an operating life such as that of the LED lamp in Patent literature article 1. Further, if a metal heat dissipator such as that in Patent literature article 1 is installed on the lower surface of the LED sub^¬ strate in order to allow heat generated by the LEDs to es^¬ cape, then because there is a large number of LEDs and the LEDs are arranged along an elongated cylindrical bulb, not only is the heat dissipator heavy, but also the heat dissi- pation efficiency deteriorates as the length of the elon^¬ gated arrangement increases.

E. In order to orient the LED light in all directions as in an HID lamp, using a large number of LEDs, LEDs must be arranged so that they are distributed in the length direction and the circumferential direction of the lamp, and both the material cost and the manufacturing cost of manufacturing an LED substrate having such a shape are high.

[Means of overcoming the problems]

[0006]

The light-emitting diode lamp according to the present invention is a light-emitting diode lamp which is provided with a light-emitting diode unit in which light-emitting diodes are mounted on the side surfaces of a prismatic or cy^¬ lindrical support member, and a housing having a glass cover which envelops the light emitting surface of the abovementioned light-emitting diode unit and which is arranged inside the light-emitting diode unit,

and in which the height of the abovementioned light- emitting diode unit in the axial direction of the support member is a length which is between 1.5 times and 3.5 times the diameter of the circumcircle of the abovementioned sup^¬ port member,

characterized in that the inner surface of the abovemen^¬ tioned glass cover is in contact with light-emitting diodes mounted on the side surfaces of the prismatic or cylindrical support member of the abovementioned light-emitting diode unit, or in that the inner surface of the abovementioned glass cover is in close proximity to, namely 5mm or less from, the abovementioned light-emitting diodes.

[0007]

A characteristic is that a space between the light emitting surface of the abovementioned light-emitting diode unit and the inner surface of the glass cover is filled with a ther^¬ mally conductive medium which is transparent and electri^¬ cally insulating.

[0008]

A characteristic is that the abovementioned thermally con- ductive medium is a silicone resin.

[0009]

A characteristic is that the abovementioned thermally con^¬ ductive medium is a fluid of density 1.5 or more.

[0010]

A characteristic is that the abovementioned thermally con^¬ ductive medium is a perfluorocarbon liquid.

[0011]

A characteristic is that the abovementioned housing com^¬ prises a glass bulb, the inside of the abovementioned glass _n

5 bulb is filled with an inert gas, and the abovementioned glass bulb is closed and hermetically sealed by means of a glass bulb end portion through which the lead wires lead out to the outside of the glass bulb.

[0012]

The light-emitting diode lamp as claimed in claim 6, characterized in that the abovementioned light-emitting diode unit is provided at its bottom portion with a support strut, the abovementioned support strut is implanted in a sealing portion of the abovementioned glass bulb,

and the abovementioned light-emitting diode unit is re^¬ tained within the abovementioned glass bulb by means of the support strut implanted in the sealing portion of the above- mentioned glass bulb.

[0013]

A characteristic is that the abovementioned light-emitting diodes are mounted on substrates,

and the abovementioned substrates are installed on the side surfaces and the upper surface of the abovementioned support member.

[0014]

A characteristic is that the abovementioned light-emitting diodes are mounted directly on the side surfaces and the up^¬ per surface of the abovementioned support member.

[0015]

A characteristic is that fixed to the abovementioned hous^¬ ing is a cap, being a screw-shaped metallic cap which mates with the end portion, to which lead wires which lead out from the abovementioned light-emitting diode unit are wired.

[0016]

The lighting fixture according to the present invention is characterized by being provided with the abovementioned light-emitting diode lamp and a lighting device.

[Advantages of the invention] ,

b

[0017]

According to the present invention, by arranging that the light-emitting diode unit is longer than the diameter of the support member it is possible to obtain a broader light dis- tribution and light emission intensity in the length direc^¬ tion of the lamp in the same way as with an HID lamp, and by making it possible for heat to be dissipated efficiently from the side surfaces of the light-emitting diode unit it is possible to provide a light-emitting diode lamp having a longer operating life.

[Brief explanation of the figures]

[0018]

[Figure 1] Front side view of the light-emitting diode unit 10 of embodiment 1.

[Figure 2] Plan view of the light-emitting diode unit 10 of embodiment 1.

[Figure 3] Front side view of the light-emitting diode lamp 20 of embodiment 1.

[Figure 4] Plan view of the light-emitting diode lamp 20 of embodiment 1.

[Figure 5] Front side view of the light-emitting diode lamp 20 of embodiment 1 without the cap 23.

[Figure 6] Diagram illustrating the variation in color temperature of the light-emitting diode lamp 20 of embodiment 1.

[Figure 7] Illustration of the support member 13 of the light-emitting diode unit 10 of embodiment 3, in an unfolded state .

[Figure 8] Front side view of the support member 13 of the light-emitting diode unit 10 of embodiment 3.

[Figure 9] Plan view of the support member 13 of the light- emitting diode unit 10 of embodiment 3.

[Figure 10] Front side view of the light-emitting diode unit 10 of embodiment 3. [Figure 11] Plan view of the light-emitting diode unit 10 of embodiment 3.

[Figure 12] Front side view of the light-emitting diode lamp 20 of embodiment 3.

[Figure 13] Plan view of the light-emitting diode lamp 20 of embodiment 3.

[Figure 14] Dimensioned drawing of the light-emitting diode lamp 20 of embodiment 3.

[Figure 15] Diagram showing Table 1, Table 2 and Table 3 of embodiment 3.

[Figure 16] Diagram showing Table 4 of embodiment 3.

[Figure 17] Plan view of the light-emitting diode lamp 20 of embodiment 3 with a light-emitting diode unit 10 in the shape of a hexagonal prism.

[Figure 18] Diagram showing Table 5 of embodiment 3.

[Figure 19] Diagram showing tables of comparative examples in embodiment 3.

[Figure 20] Front side view of the light-emitting diode unit 10 of embodiment 4.

[Figure 21] Plan view of the light-emitting diode unit 10 of embodiment 4.

[Figure 22] Front side view of the light-emitting diode lamp 20 of embodiment 4.

[Figure 23] Plan view of the light-emitting diode lamp 20 of embodiment 4.

[Figure 24] Diagram showing Table 6 of embodiment 4.

[Figure 25] Diagram showing a graph of h/D against bulb surface temperature from Table 6 of embodiment 4.

[Figure 26] Diagram showing Table 7 of embodiment 4.

[Figure 27] Diagram showing a graph of h/D against bulb surface temperature from Table 7 of embodiment 4.

[Figure 28] Diagram showing Table 8 of embodiment 4.

[Figure 29] Diagram showing a graph of Ad against bulb sur^¬ face temperature from Table 8 of embodiment 4. [Figure 30] Diagram illustrating the light-emitting diode lamp 20 of embodiment 5 with an octagonal prismatic support member 13.

[Figure 31] Diagram illustrating the light-emitting diode lamp 20 of embodiment 5 with a hexagonal prismatic support member 13.

[Figure 32] Diagram illustrating a lighting fixture equipped with the light-emitting diode lamp 20 of embodiment 5.

[Figure 33] Diagram illustrating a lighting fixture equip- ped with the light-emitting diode lamp 20 of embodiment 5.

[Figure 34] Diagram illustrating a lighting fixture equipped with the light-emitting diode lamp 20 of embodiment 5.

[Modes of embodying the invention]

[0019]

Embodiment 1.

(1) First embodiment (Figure 1 to Figure 6)

Figure 1 shows a front side view of a light-emitting diode unit 10, and Figure 2 shows a plan view thereof.

Figure 3 shows a front side view of a light-emitting diode lamp 20, and Figure 4 shows a plan view thereof. Figure 5 shows a front side view without the cap 23.

A light-emitting diode unit 10 is provided with an aluminum octagonal prismatic support member 13. The support member 13 is a retaining member which retains light-emitting diodes 11. The light-emitting diode unit 10 is provided at the top portion of the support member 13 with a trapezoidal pyramid 18 having eight surfaces.

[0020]

Ribbon-shaped flexible substrates 12 (light-emitting diode substrates) each of which is equipped with one light- emitting diode 11 are affixed to the eight surfaces of the pyramid 18 using heat-resistant adhesive. Further, ribbon- shaped flexible substrates 12 (light-emitting diode sub^¬ strates) each of which are equipped with three light- _

y emitting diodes 11 are affixed to the eight side surfaces of the octagonal prism using heat-resistant adhesive.

[0021]

A pair of base portion support struts 14 are fitted in the axial direction of the octagonal prism to the base portions of one side surface of the octagonal prism and the opposing side surface thereof (the base portions on the cap 23 side of a pair of opposing side surfaces) .

Further, an axial support strut 15 is also fitted in the axial direction of the octagonal prismatic support member 13, at the center of the bottom surface of the octagonal prism.

[0022]

Lead wires 17 through which a direct current enters and leaves the light-emitting diodes 11 are led out from the bottom surface of the octagonal prismatic support member 13.

[0023]

These three support struts are linked to a separate linking support strut 16 that is oriented in a direction that is perpendicular to the axial direction of the octagonal pris^¬ matic support member 13.

Each of these support struts is made from stainless steel.

[0024]

For example, the diameter of the circumcircle of the bottom surface of the octagonal prismatic support member 13 is

50mm, and the height of the section of the octagonal pris^¬ matic support member 13 not including the cone section is 150mm.

The substrates equipped with light-emitting diodes 11 are the flexible substrates 12. The flexible substrates 12 are equipped with the light-emitting diodes 11, and the flexible substrates 12 are affixed to an aluminum substrate. A poly^¬ hedral structure in the shape of a prism is formed by link^¬ ing the oblong substrates. By arranging that the top portion of the polyhedral structure in the shape of a prism is in the shape of a pyramid, it can be made to conform to a hemi^¬ spherical or dome-shaped top portion of a glass bulb 21. A light-emitting diode 11 may be arranged on the pyramid- shaped section. The angle of bend of the pyramid-shaped sec^¬ tion is determined according to the radius R of the top por^¬ tion of the glass bulb 21.

[0025]

The light-emitting diode lamp 20 will be described with re- ference to Figure 3, Figure 4 and Figure 5.

The light-emitting diode lamp 20 is provided with a housing 24. The housing 24 is provided with a glass bulb 21 and a flare tube 22. All of the housing 24 is transparent. Alter^¬ natively, the lower portion of the housing 24 where light- emitting diodes 11 are not arranged may be non-transparent. The glass bulb 21 is in the shape of a cylinder having a he^¬ mispherical upper portion.

[0026]

The light-emitting diode unit 10 is inserted into the glass bulb 21. A transparent thermally conductive silicone resin (silicone rubber KE109 manufactured by Shin-Etsu Silicone; not shown in the diagrams) fills the space between the glass bulb 21 and the light-emitting diode unit 10 from the inner surface of the hemispherical top portion of the glass bulb 21 to the height of the bottom surface of the octagonal prismatic support member 13 of the light-emitting diode unit 10.

[0027]

The flare tube 22 is a glass sealing portion which is fu- sion bonded to the end portion of the glass bulb 21.

The axial support strut 15 which leads out from the center of the bottom surface of the octagonal prismatic support member 13 in the axial direction of the octagonal prismatic support member 13 is implanted in the flare tube 22 such that the end portion of the axial support strut 15 becomes embedded when the flare tube 22 is pinched. The lead wires 17 which lead out from the bottom surface of the octagonal prismatic support member 13 are implanted in the flare tube 22 such that the end portions of the lead wires 17 lead out from the end portion of the flare tube 22 when the glass flare tube 22 which is fusion bonded to the end portion of the glass bulb 21 is pinched.

[0028]

When the tip tube at the end portion of the glass bulb 21 is sealed, air inside the bulb is replaced by filling it with nitrogen gas.

[0029]

The two lead wires 17 are wired to an E39 cap 23 that is installed at the end portion of the glass bulb 21.

[0030]

As shown in Figure 6, lamps filled with thermally conduc^¬ tive silicone resin have a higher color temperature than those which are not filled (filled only with nitrogen) , and the lamp color is shifted in the blue direction and appears brighter. Also, because the color temperature of the lamp is raised it is possible to use a light-emitting diode 11 that has a lower color temperature. By this means it is possible to reduce the amount of yellow YAG phosphor used, this being a cause of deterioration in the most typical type of pseudo- white light-emitting diode 11 comprising a blue light- emitting diode 11 to which yellow YAG phosphor is applied.

[0031]

With regard to the reason why the color of the lamp shifts in the blue direction when the lamp is filled with thermally conductive silicone resin, it is thought that this is due to absorption of colors from infra-red to red by organic sub^¬ stances such as silicone resin, although this is not cer^¬ tain . [0032]

It should be noted that an E39 cap 23 is used for the cap 23, but an E26 cap 23 compatible with HID lamps may also be used .

[0033]

Embodiment 2.

(2) Second embodiment (no diagrams)

Instead of the transparent thermally conductive silicone resin used in the first embodiment, filling may be performed using a perfluorocarbon liquid, as a transparent thermally conductive liquid. Perfluorocarbon liquids have a high den^¬ sity and efficiently absorb heat generated by the light- emitting diodes 11 and transfer it to the glass bulb 21. Perfluorocarbon liquids are electrically insulating liquids, and so there is no danger of shorting even if the liquid co^¬ mes into contact with wiring such as the lead wires 17.

[0034]

As shown in Figure 6, lamps filled with a perfluorocarbon liquid have a higher color temperature than those which are not filled (filled only with nitrogen) , and the lamp color is shifted in the blue direction and appears brighter. Also, because the color temperature of the lamp is raised it is possible to use a light-emitting diode 11 that has a lower color temperature. By this means it is possible to reduce the amount of yellow YAG phosphor used, this being a cause of deterioration in the most typical type of pseudo-white light-emitting diode 11 comprising a blue light-emitting diode 11 to which yellow YAG phosphor is applied.

[0035]

With regard to the reason why the color of the lamp shifts in the blue direction when the lamp is filled with a per- fluorocarbon liquid, it is thought that this is due to ab^¬ sorption of colors from infra-red to red by the perfluoro- carbon liquid, although this is not certain. [0036]

The lamp is filled, for example, with ' Fluorinert ' ( ^xFluo- rinert ' is a registered trade mark) FC-3283 manufactured by Sumitomo 3M Ltd, which has a density of 1.83 (kg/m³ @25°C) , a specific heat of 1.050 (J/kgK @25°C) , a dielectric strength of 43kV(2.54mm Gap @25°C) , and a conductivity of 1.91kV (@25°C) [1kHz] C@25°C' means 'at 25°C).

[0037]

It should be noted that perfluorocarbon liquids are trans- parent and electrically insulating, and if the density is higher than that of water and the specific heat is similar to that of water then the liquid can directly cool the light-emitting diode substrate while electricity is being conducted, and also heat dissipation efficiency is better than with cooling water, and so a density of 1.5 (kg/m³@25°C) or more is sufficient.

[0038]

'Fluorinert' ('Fluorinert' is a registered trade mark) FC- 72 manufactured by Sumitomo 3M Ltd, which has a density of 1.68 (kg/m³ @25°C) , a specific heat of 1.050 (J/kgK @25°C) , a dielectric strength of 38kV (2.54mm Gap @25°C) , and a con^¬ ductivity of 1.76kV (@25°C) [1kHz] may for example also be used .

[0039]

Embodiment 3.

(3) Third embodiment (Figure 7 to Figure 13)

An explanation will now be given regarding the differences with embodiments 1 and 2.

Figure 7 shows an illustration of a support member 13 of a light-emitting diode unit 10 in an unfolded state.

Figure 8 and Figure 9 show a front side view and a plan view of a support member 30, formed by folding and assem^¬ bling the support member 13. Figure 7 shows the support mem^¬ ber 13 before light-emitting diodes have been mounted. Light-emitting diodes and circuitry are mounted onto the support member 13 shown in Figure 7, after which it is folded and assembled into the shape of the support member 30 shown in Figure 8 and Figure 9 after folding and assembly.

[0040]

As shown in Figure 7, Figure 8 and Figure 9, the support member 13 is formed into a three-dimensional shape by bend^¬ ing an integrated aluminum sheet, forming a plurality of surfaces. The thermal conductivity is improved by forming the support member by folding an integrated sheet.

[0041]

Figure 10 shows a front side view of the light-emitting di^¬ ode unit 10, and Figure 11 shows a plan view thereof.

[0042]

The aluminum octagonal prismatic support member 13 is pro^¬ vided at its top portion with an aluminum octagonal pyramid.

Four of the eight surfaces of the octagonal pyramid are each equipped with one light-emitting diode 11. Further, each of the eight surfaces of the octagonal prismatic sup- port member 13 is equipped with a row of three light- emitting diodes 11.

The abovementioned support member 13 is treated such that it is electrically insulating, and it also functions as the light-emitting diode substrate.

[0043]

Figure 12 shows a front side view of a light-emitting diode lamp 20, and Figure 13 shows a plan view thereof.

[0044]

The light-emitting diode unit 10 is inserted into a cylin- drical glass bulb 21 having a hemispherical upper portion, and a transparent thermally conductive medium (not shown in the diagrams) which fills the space between the glass bulb 21 and the light-emitting diode unit 10 is the same as in embodiments 1 and 2. [0045]

As shown by way of example in Figure 7 and Figure 17, the width w, in a direction perpendicular to the axis of the octagonal prismatic support member 13, of the side surfaces of the octagonal prismatic support member 13 of the abovemen- tioned lamp (the width w of one side surface of the octago^¬ nal prism) is 17.15mm.

The distance Ak from the point at which a line extending perpendicular to a side surface of the octagonal prismatic support member 13 from the center of a cross section through the cylindrical bulb intersects the side surface of the oc^¬ tagonal prismatic support member 13, to the point at which the perpendicularly extended line intersects the inner sur^¬ face of the bulb (the distance Ak from the center of one surface of the abovementioned support member 13 to the inner surface of the bulb) is 2.4mm.

The height h of the octagonal prismatic support member 13 is 110mm.

[0046]

The internal bulb diameter D of a glass bulb 21 having an

E39 cap 23 specification is 48mm.

The diameter d of the circumcircle of the octagon is

44.8mm.

[0047]

(Determining n for the polygon)

A polygon is selected which satisfies the following crite^¬ ria: the width w of a side surface of the polygonal prism in a direction perpendicular to the axis of the polygonal prism is 17.15mm;

the distance Ak from the point at which a line extending perpendicular to a side surface of the polygonal prism from the center of a cross section through the cylindrical bulb intersects the side surface of the polygonal prism, to the point at which the perpendicularly extended line intersects the inner surface of the bulb is 3.0mm;

and the internal diameter D of a glass bulb 21 which is compatible with an HID lamp having an E39 cap 23 specifica- tion is 48mm.

[0048]

The meaning of the symbols in the dimensioned drawing in Figure 14 are as follows.

D: Internal diameter of the glass bulb 21

d: Diameter of the circumcircle of the light-emitting diode unit 10

w: Width of one surface of the light-emitting diode unit 10 b: Distance from the center of the glass bulb 21 to the light-emitting diode 11

Ar : Difference between the inner diameter D of the glass bulb 21 and the diameter d of the circumcircle

Ak: Distance in the radial direction from the light- emitting diode 11 to the inner surface of the glass bulb 21

Ag: Distance in the radial direction from the light- emitting diode 11 to the circumcircle

The width w of one side surface of the light-emitting diode unit 10 is equal to or greater than the size in the width direction of the light-emitting diode 11, and is equal to or greater than a width that permits wiring of signal wires. Further, if a flexible substrate is to be affixed, the width w is equal to or greater than the width of the flexible sub^¬ strate and is equal to or greater than a width that permits wiring of signal wires.

[0049]

If the width w is increased then n decreases, with the fol^¬ lowing merits.

1. The number of folds of the support member 13 decreases.

2. Positioning the pyramid 18 at the top portion is simpler . [0050]

If the width w is decreased then n increases, with the fol^¬ lowing merits.

1. The light-emitting diodes 11 move closer to the inner surface of the glass bulb 21.

2. Heat dissipation effects are increased (embodiment 4 de^¬ scribed hereinbelow)

[0051]

The diameter d of the circumcircle of the n-sided polygon having sides of a length equal to the width w of a side sur^¬ face of the polygonal prism in a direction perpendicular to the axis of the polygonal prism can be expressed, based on the following equation,

Sin (180°/n) =w/d

as

d=w/Sin (180°/n)

[0052]

The difference Ag between (d/2) and the distance b between the center of the polygon and the point at which a line ex- tending from the center perpendicular to a side of the polygon intersects the side can be expressed, based on the fol^¬ lowing equations,

Ag=d/2-b

b=V( (d/2)²- (w/2)²)

as

Ag=(d/2)- ( (d/2)²- (w/2)²)

[0053]

The distance Ar between the inner circumference of the bulb and the circumference of the circumcircle of the polygon, arranged concentrically, can be expressed as

Ar=Ak-Ag

[0054]

For a given value of w, the internal diameter D of a bulb satisfying Ak can be expressed as follows D=d+2Ar

=d+2 (Ak-Ag)

=d+2 (Ak- (d/2) + ( (d/2) ²- (w/2) ²) )

=d+2Ak-d+2 ( (d/2) ²- (w/2) ²)

=2Ak+2 ( (w/2 Sin (180°/n) ) ²- (w/2) ²)

[0055]

This equation shows that the internal diameter D of the glass bulb 21 is a function of Ak, w and n. It also shows that if Ak and w are fixed then the internal diameter D of the glass bulb 21 is a function of n. Conversely, it also shows that if the values of Ak, w and the internal diameter D are prescribed, then n is determined.

[0056]

If w=17.15mm and Ak=3.0mm, then according to Table 1 in Figure 15, the closest value to the target value of D=48mm is D=47.40, obtained when n=8.

[0057]

If the target value is equal to or less than D=48mm then the largest value of n corresponding to the value equal to or less than D=48mm should be selected.

[0058]

As described above, it can be seen that if the width w of one side surface of the support member 13 is fixed at a pre- scribed width w=17.15mm, and the distance Ak from the center of one side surface of the abovementioned support member 13 to the inner surface of the bulb is fixed at a prescribed distance Ak=3.0mm, then the regular n-sided polygon whereby the abovementioned light-emitting diode unit 10 can be ar- ranged inside a cylindrical bulb having a prescribed bulb diameter D=48mm is a regular octagon. In other words, the optimal value of n for a regular n-sided polygon whereby the abovementioned light-emitting diode unit 10 can be arranged inside a cylindrical bulb having the prescribed bulb diame^¬ ter is 8.

[0059]

If w=17.15mm and Ak=4.0mm, then according to Table 2 in Fi- gure 15, the closest value to the target value of D=48mm is D=49.40, obtained when n=8.

[0060]

According to Table 4 in Figure 16, when in practice D=48mm is adopted, Ak becomes 3.3mm.

Further, a polygon that satisfies the 38.6mm internal di^¬ ameter criterion for a glass bulb 21 which is compatible with an HID lamp having an E26 cap 23 specification can be selected from the tables in Figure 15.

[0061]

According to Table 2 and Table 3 in Figure 15, the closest values to the target value of D=38.6mm are D=37.7 and

D=39.7, obtained when n=6 (Figure 17) .

[0062]

According to Table 4 in Figure 16, when in practice

D=38.6mm is adopted, Ak becomes 4.5mm.

[0063]

A value of w=17.15mm is preferred because a target value of D=48mm and a target value of D=38.6mm can be achieved using values of n of between 6 and 8.

[0064]

Ideally the abovementioned light-emitting diode unit 10 should preferably be in the shape of a circular prism, but flat surfaces are necessary in order to arrange the light- emitting diodes 11. It is thus formed in the shape of a po- lygon, but this polygon should ideally be similar to a cir^¬ cular prism. However, although n increases if the width w decreases, and so the shape approaches that of a circular prism, there is a concomitant complication of the manufac^¬ turing process due to an increase in the number of folds. [0065]

If the width w is increased then n decreases, and the light-emitting diode unit 10 becomes a triangular prism or a square prism, having a shape that is far from that of a cir- cular prism.

[0066]

Table 5 in Figure 18 describes cases in which w=5mm, 15mm and 20mm, and Ak=5.0mm.

[0067]

A value of w=5mm is not suitable to achieve a target value of D=48mm because D does not reach 40mm or more even if n=18 when w=5mm.

[0068]

A value of w=15mm is preferred because a target value of D=48mm and a target value of D=38.6mm can be achieved using values of n of between 6 and 8.

[0069]

A value of w=20mm is not suitable to achieve a target value of D=38.6mm because D does not reach 40mm or less even if n=6 when w=20mm.

[0070]

Figure 19 shows tables for cases in which Ak=1.5mm and Ak=2.0mm, where w=17.15mm. A negative value of Ar indicates that the light-emitting diode unit 10 cannot be housed within the glass bulb 21. Although the light-emitting diode unit 10 can theoretically be housed within the glass bulb 21 when Ar is less than 1mm, insertion of the light-emitting diode unit 10 into the glass bulb 21 during assembly is dif^¬ ficult due to dimensional variations in the glass bulb 21 (plus or minus 1 to 2mm) and the like.

[0071]

Figure 15, Figure 16, Figure 18 and Figure 19 show calcu^¬ lated values of w/d and w/D. As explained hereinabove, because Sin ( 180 ° /n) =w/d, accord^¬ ing to this equation if n is determined then the ratio be^¬ tween w and d can be found.

[0072]

When n= ^:4, Sin (18 0 °/n) =0 .71=w/d

When n= ^:5, Sin (18 0 °/n) =0 .59=w/d

When n= ^:6, Sin (18 0 °/n) =0 .50=w/d

When n= -Ί , Sin (18 0 °/n) =0 .43=w/d

When n= ^Q, Sin (18 0 °/n) =0 .38=w/d

When n= ^■9, Sin (18 0 °/n) =0 .34=w/d

When n= ^:10, Sin (1 8 0°/n ) = 0.31=w/d

Therefore, to obtain a value of n of between 4 and 10, w should be equal to d multiplied by between 0.71 and 0.31. To obtain a value of n of between 6 and 8, w should be equal to d multiplied by between 0.5 and 0.38.

[0073]

In practice, as shown in Figure 15, Figure 16, Figure 18 and Figure 19, if n and Ak are defined then the ratio be^¬ tween w and D can be obtained from the following equation D=2Ak+2 ( (w/2Sin (180°/n) ) ²- (w/2) ²) )

[0074]

According to Table 1 of Figure 15, to obtain a value of n of between 4 and 10 when Ak=3.0mm, w should be equal to D multiplied by between 0.74 and 0.29. To obtain a value of n of between 6 and 8, w should be equal to D multiplied by be^¬ tween 0.48 and 0.36.

[0075]

According to Table 2 of Figure 15, to obtain a value of n of between 4 and 10 when Ak=4.0mm, w should be equal to D multiplied by between 0.68 and 0.28. To obtain a value of n of between 6 and 8, w should be equal to D multiplied by be^¬ tween 0.45 and 0.35.

[0076] According to Table 3 of Figure 15, to obtain a value of n of between 4 and 10 when Ak=5.0mm, w should be equal to D multiplied by between 0.63 and 0.27. To obtain a value of n of between 6 and 8, w should be equal to D multiplied by be^¬ tween 0.43 and 0.33.

[0077]

According to Table 4 of Figure 16,

when D=48mm, w=17.15mm is 0.36 times the value of D;

when D=38.6mm, w=17.15mm is 0.44 times the value of D.

[0078]

As described above, w should be in the range of 0.27 to 0.74 multiplied by D. Preferably w should be in the range of 0.33 to 0.38 multiplied by D. Further, because it is prefer^¬ able for Ak to be small, w should be in the range of 0.48 to 0.36 multiplied by D.

[0079]

According to Figure 15 to Figure 19, preferred values of n to obtain values of D that are closest to the target D=48mm are as follows.

When w=17.15mm and Ak=3.0mm, n=8

When w=17.15mm and Ak=4.0mm, n=8

When w=15.00mm and Ak=5.0mm, n=8

When w=20.00mm and Ak=5.0mm, n=6

[0080]

Preferred values of n to obtain values of D that are clos^¬ est to the target D=36.8mm are as follows.

When w=17.15mm and Ak=3.0mm, n=6

When w=17.15mm and Ak=4.0mm, n=6

When w=15.00mm and Ak=5.0mm, n=6

When w=5.00mm and Ak=5.0mm, n=17

[0081]

It should be noted that n may be an odd number, but if it is an even number, the structure of the support struts is simplified, facilitating manufacture. [0082]

An advantage of employing a regular n-sided polygonal light-emitting diode unit 10, where a preferred value of n has been determined in this way, is that it is not necessary to alter the width w of the side surfaces of the light- emitting diode unit 10 even if the diameter of the glass bulb 21 is varied, and thus components of the light-emitting diode unit 10 can be standardized.

[0083]

A further advantage of employing a regular n-sided polygo^¬ nal light-emitting diode unit 10 having a preferred value of n is that the distance Ak between the light-emitting diodes 11 and the inner surface of the glass bulb 21 can be main^¬ tained at a fixed or substantially fixed value even if the diameter D of the glass bulb 21 is varied. If the distance Ak between the light-emitting diodes 11 and the inner surface of the glass bulb 21 is set such that it is a distance that allows heat from the light-emitting diodes 11 to escape efficiently to the glass bulb 21 (a distance described in embodiment 4 hereinbelow) , then a lamp having a high heat dissipation effect can be obtained. Lamps having the same or substantially the same heat dissipation effect can be ob^¬ tained even when lamps are manufactured using glass bulbs 21 of different diameters.

[0084]

Embodiment 4.

(4) Fourth embodiment (Figure 20 to Figure 29)

Preferred ratios between the height and the diameter of the light-emitting diode unit 10, and the distance between the light-emitting diodes 11 and the diametrically inner portion of the glass bulb 21 will now be discussed.

[0085]

(Test procedure)

(Figure 20 to Figure 23) ^• Light-emitting diode units 10 in which the diameter D of the circumcircle of the octagonal prismatic support member 13 and the height h of the octagonal prismatic support mem^¬ ber 13 were varied, were prepared using aluminum support members that also function as light-emitting diode sub^¬ strates, in the same way as in embodiment 3 (Figure 22, Fig^¬ ure 21).

^• The octagonal pyramid at the top portion was omitted. Each side surface of the octagonal prismatic support member 13 was equipped with a longitudinal row of three light- emitting diodes 11.

^• The light-emitting diode unit 10 was equipped in total with 24 light-emitting diodes 11, with one mounted at each of the following three locations:

A. The midpoint of each surface in the height direction

(point b)

B. The midpoint between the light-emitting diode 11 in the location mentioned in A hereinabove and the top edge of the side surface (point a)

C. The midpoint between the light-emitting diode 11 in the location mentioned in A hereinabove and the bottom edge of the side surface (point c) .

^• The end portion of the glass bulb 21 was sealed in the same way as in embodiment 1 and embodiment 3, and the lamp was prepared using a method whereby a screw-type cap 23 was fitted .

^• Two types of lamp were prepared (Figure 22), namely one filled only with nitrogen gas and sealed, and one in which substantially all of the space was filled with a perfluoro- carbon after which it was sealed while nitrogen gas was be^¬ ing injected.

[0086] In all cases the distance 1 between the upper surface of the light-emitting diode unit 10 and the inner surface of the top portion of the glass bulb 21 was 20mm.

^• The volume V defined by the diameter of the circumcircle of the light-emitting diode unit 10 and the height of the prism was unified such that it was possible to compare light-emitting diode units 10 having different D:h ratios. Although the ease with which a lamp is fitted to a fixture is also influenced greatly by the shape of the fixture, the conditions relating to the ease with which lamps employing light-emitting diode units 10 having different D:h ratios were fitted to a fixture were readily aligned by unifying the values of the abovementioned V.

^• The distance Ad between the light-emitting diodes 11 and the diametrically inner portion of the glass bulb 21 was va^¬ ried by altering the diameter of the glass bulb 21 (Figure 23) .

^• Conditions such as the power, voltage and current of each lamp were unified, and the lamps were lit with the cap 23 portion at the bottom. The temperature of the outer surface of the glass bulb 21 was measured at the following three points .

A point corresponding to the location of the upper portion light-emitting diode 11 (B. mentioned above) : point a

A point corresponding to the location of the middle portion light-emitting diode 11 (A. mentioned above) : point b

A point corresponding to the location of the lower portion light-emitting diode 11 (C. mentioned above) : point c

[0087]

(Results)

(Preferred h/D)

^• Figure 24, Table 6: Nitrogen gas filling, no transparent thermally conductive medium. As shown in Figure 25, the temperature decreases as h/D in^¬ creases. In the range in which h/D is approximately 1.5 and larger, even point a which has the highest temperature is lower than 100°C. Also, the gradient of temperature decrease becomes more gradual as h/D increases from approximately 1.5 to 2.0. This trend becomes more marked in the vicinity of the light-emitting diodes 11 and at point a which is in the upper portion of the lamp.

^• Figure 26, Table 7: Nitrogen gas filling, with transpar- ent thermally conductive medium (perfluorocarbon liquid) .

As shown in Figure 27, the overall temperature is lower than in Table 6. This is an effect of the transparent ther^¬ mally conductive medium (perfluorocarbon liquid) .

The temperature decreases as h/D increases. The gradient of temperature decrease becomes more gradual as h/D increases from approximately 1.5 to 2.0. This trend becomes more mark^¬ ed in the vicinity of the light-emitting diodes 11 and at point a which is in the upper portion of the lamp, and these and other effects show similar trends to those observed without the transparent thermally conductive medium, al^¬ though not so marked.

[0088]

It should be noted that although the temperature decreases as h/D increases, the trend is almost negligible for values of h/D above approximately 3.0.

[0089]

Also, when h/D exceeds 3.5, the lamp must be elongated in shape, and the dimensions are markedly different from those of HID lamps used in conventional street lights, and thus ease of fitting to a fixture deteriorates.

[0090]

The value of h/D is preferably in a range of between 1.5 and 3.5, and more preferably in a range of between 2.0 and 3.0. [0091]

(Preferred Ad and preferred Ak)

Preferred values of the distance between the light-emitting diodes 11 and the inner surface of the glass bulb 21 will now be discussed.

^• Figure 28, Table 8: Nitrogen gas filling, with transparent thermally conductive medium (perfluorocarbon liquid) .

^• The distance Ad in the diametrical direction between the outer surface of the light-emitting diodes 11 and the inner surface of the glass bulb 21 was varied by altering the di^¬ ameter of the glass bulb 21 (Figure 23) .

[0092]

As shown in Figure 29, the temperature increases as the light-emitting diodes 11 move away from the inner surface of the bulb.

[0093]

There is a difference of 20°C to 35°C between the cases in which the light-emitting diodes 11 are in contact with the inner surface of the bulb and the cases in which they are separated from the inner surface of the bulb by 20mm.

[0094]

It is advantageous in terms of temperature for the light- emitting diodes 11 to be in contact with the inner surface of the bulb or close to the inner surface of the bulb as heat dissipation effects are improved.

[0095]

When the light-emitting diodes 11 are separated from the inner surface of the bulb, either the bulb must be made fat^¬ ter or the light-emitting diode unit 10 made thinner. Making the bulb fatter is disadvantageous in terms of ease of fit^¬ ting to a fixture, and making the light-emitting diode unit 10 thinner is disadvantageous in terms of light distribu^¬ tion.

[0096] As shown in Figure 29, the temperature gradient in the ran^¬ ge in which Ad is 5mm or less is steeper than the tempera^¬ ture gradient in the range of 5mm and above, and it is thus preferable for Ad to be 5mm or less and as close as possible to Omm.

[0097]

Thus the preferred range of Ad is Omm or more and 5mm or less. Ad is preferably close to Omm.

[0098]

The thickness X of the light-emitting diodes 11 is at least lmm. Because Ak=Ad+X, the preferred range of Ak is 1mm or more and 6mm or less.

[0099]

There are, in practice, errors in manufacturing and design such as dimensional variations between the surfaces of the prismatic support member 13, variations in the height (di^¬ mension X) of the light-emitting diodes 11, variations in the height at which the light-emitting diodes 11 are ad^¬ hered, and variations in the dimensions of the glass bulb 21.

[0100]

Using a design specification whereby the light-emitting diodes 11 are in contact with the inner surface of the bulb, or a design specification whereby they are close to the in- ner surface of the bulb, insertion of the light-emitting di^¬ ode unit 10 into the glass bulb 21 during assembly is diffi^¬ cult because variations between the heights of the light- emitting diodes 11 are approximately lmm, due to the above- mentioned dimensional variations. In order to insert the light-emitting diode unit 10 into the glass bulb 21 during assembly it is necessary to have a minimum clearance (Ar) around the full 360° in the circumferential direction.

[0101] If the height (thickness X) of the light-emitting diodes 11 is Ag or less, then a clearance (ΔΓ) can be provided around the full 360° in the circumferential direction without the outer surface of the light-emitting diodes 11 protruding from the circumcircle .

[0102]

According to Figure 19 of embodiment 3, the clearance (Ar) is less than 1mm when Ak is 2mm or less, and this is not de^¬ sirable. Therefore a more preferred range of Ak is 2mm or more and 6mm or less. From the viewpoint of the heat dissi^¬ pation effect it is preferable for Ak to be 2mm or close to 2mm.

[0103]

Embodiment 5.

(5) Fifth embodiment (Figure 30 to Figure 34)

Figure 30 is a diagram illustrating a light-emitting diode lamp 20 with an octagonal prismatic support member 13.

Figure 31 is a diagram illustrating a light-emitting diode lamp 20 with a hexagonal prismatic support member 13.

Figure 32 to Figure 34 show a lighting fixture equipped with a light-emitting diode lamp 20. Because the light dis^¬ tribution is not oriented, but the light from the light- emitting diodes 11 is distributed in approximately all di^¬ rections, the lamp is not only applicable to street lights having substantially horizontal lights, which predominantly illuminate a lower surface (Figure 32) but also to base-down and base-up lighting fixtures (Figure 33, Figure 34) .

[0104]

The characteristics of the configurations of the light- emitting diode lamp 20 in the abovementioned embodiments 1 to 5 can be divided broadly into two groups, and the charac^¬ teristics and advantages will now be described.

[0105]

*** First characteristic group *** Characteristic 1.

In a light-emitting diode lamp 20, a light-emitting diode unit 10 comprising a prismatic or cylindrical support member 13 on which light-emitting diodes 11 are mounted is arranged inside a housing 24, and lead wires 17 which lead out from the abovementioned light-emitting diode unit 10 are wired to a cap 23 which mates with the end portion of the abovementioned housing 24.

In a light-emitting diode lamp 20, the light emitting sur- face of the abovementioned light-emitting diode unit 10 is enveloped by a glass cover comprising part of the abovemen^¬ tioned housing 24, and the inner surface of the abovemen^¬ tioned glass cover is in close proximity with or in contact with light-emitting diodes 11 mounted on the side surfaces of the prismatic or cylindrical support member 13 of the abovementioned light-emitting diode unit 10.

The light-emitting diode lamp 20 is characterized in that the height of the abovementioned light-emitting diode unit 10 in the axial direction of the prismatic or cylindrical support member 13 is longer than the diameter of the circum- circle of the bottom surface of the abovementioned prismatic support member 13 or the diameter of the bottom surface of the abovementioned cylindrical support member 13.

[0106]

Characteristic 2.

A characteristic is that the height in the axial direction of the prismatic or cylindrical support member 13 of the abovementioned light-emitting diode unit 10 is a length of between 1.5 times and 3.5 times the diameter of the circum- circle of the bottom surface of the abovementioned prismatic support member 13 or the diameter of the bottom surface of the abovementioned cylindrical support member 13.

[0107]

Characteristic 3. A characteristic is that the inner surface of the abovemen^¬ tioned glass cover is in close proximity to, namely 5mm or less from, light-emitting diodes 11 mounted on the side sur^¬ faces of the prismatic or cylindrical support member 13 of the abovementioned light-emitting diode unit 10.

[0108]

Characteristic 4.

A characteristic is that a space between the light emitting surface of the abovementioned light-emitting diode unit 10 and the inner surface of the glass cover is filled with a thermally conductive medium which is transparent and elec^¬ trically insulating.

[0109]

Characteristic 5.

A characteristic is that the abovementioned thermally con^¬ ductive medium which is transparent and electrically insu^¬ lating is a silicone resin.

[0110]

Characteristic 6.

A characteristic is that the abovementioned thermally con^¬ ductive medium which is transparent and electrically insu^¬ lating is a fluid of density 1.5 or more.

[0111]

Characteristic 7.

A characteristic is that the abovementioned thermally con^¬ ductive fluid of density 1.5 or more which is transparent and electrically insulating is a perfluorocarbon liquid.

[0112]

Characteristic 8.

A characteristic is that all of the abovementioned housing

24 including the abovementioned glass envelope comprises a glass bulb; the inside of the abovementioned glass bulb 21 is filled with an inert gas; and the end portion of the glass bulb 21 through which the lead wires 17 leading out from the abovementioned light-emitting diode unit 10 lead out to the outside of the glass bulb 21 is closed and her^¬ metically sealed.

[0113]

Characteristic 9.

A characteristic is that the abovementioned light-emitting diode unit 10 is retained by support struts which are im^¬ planted in the seal portion side of the abovementioned glass bulb 21.

[0114]

Characteristic 10.

A characteristic is that the abovementioned light-emitting diodes 11 are mounted on substrates, and in that the above- mentioned substrates are installed on the side surfaces and the upper surface of the abovementioned support member 13.

[0115]

Characteristic 11.

A characteristic is that the abovementioned light-emitting diodes 11 are mounted directly on the side surfaces and the upper surface of the abovementioned support member 13.

[0116]

Characteristic 12.

A characteristic is that a screw-type metallic cap 23 is fitted to the sealed end of the abovementioned glass bulb 21.

[0117]

Characteristic 13.

Also, a lighting fixture characterized in that the above- mentioned light-emitting diode lamp 20 and a lighting device are arranged therein.

[0118]

The advantages of each characteristic of the abovementioned light-emitting diode lamp 20 are as follows.

[0119] Advantages of characteristic 1

By arranging that the light-emitting diodes 11 on the light emitting surface of the side surfaces of the light-emitting diode unit 10 are enveloped in and are in close proximity to or are in contact with a glass cover having a larger thermal capacity than a resin cover, and arranging the light- emitting diode unit 10 such that the height in the axial di^¬ rection of the prismatic or cylindrical support member 13 is longer than the diameter of the circumcircle of the bottom surface of the prismatic support member 13 or the diameter of the bottom surface of the cylindrical support member 13, it is possible to obtain a broader light distribution and light emission intensity in the length direction of the lamp in the same way as with an HID lamp, and because heat can be dissipated efficiently from the side surfaces of the light- emitting diode unit 10 it is possible to provide a light- emitting diode lamp having a longer operating life.

[0120]

Advantages of characteristic 2

The height in the axial direction of the prismatic or cy^¬ lindrical portion of the prismatic or cylindrical support member 13 of the light-emitting diode unit 10 is set to be a length of between 1.5 times and 3.5 times the diameter of the circumcircle of the bottom surface of the prismatic sup- port member 13 or the diameter of the bottom surface of the cylindrical support member 13. In this way it is possible to obtain a broader light distribution and light emission intensity in the length direction of the lamp in the same way as with an HID lamp. Further, by making it possible for heat to be dissipated efficiently from the side surfaces of the light-emitting diode unit 10 it is possible to provide a light-emitting diode lamp having a longer operating life.

[0121]

Advantages of characteristic 3 By arranging that the inner surface of the glass cover is in close proximity of 5mm or less with light-emitting diodes 11 mounted on the side surfaces of the prismatic or cylin^¬ drical support member 13 of the light-emitting diode unit 10 it is possible for heat to be dissipated efficiently from the side surfaces of the light-emitting diode unit 10, and it is possible to provide a light-emitting diode lamp 20 ha^¬ ving a longer operating life.

[0122]

Advantages of characteristic 4

By arranging that the space between the light emitting surface of the light-emitting diode unit 10 and the inner sur^¬ face of the glass cover is filled with a thermally conduc^¬ tive medium which is transparent and electrically insulating it is possible for heat to be dissipated efficiently from the side surfaces of the light-emitting diode unit 10, and it is possible to provide a light-emitting diode lamp 20 ha^¬ ving a longer operating life.

[0123]

Advantages of characteristic 5

By arranging that the thermally conductive medium which is transparent and electrically insulating is a silicone resin it is possible to improve the electrical insulation proper^¬ ties and to ensure the electrical safety of the LEDs and wi- ring. Also, the color of the lamp is shifted towards the higher color temperature side and thus appears brighter.

[0124]

Advantages of characteristic 6

By arranging that the thermally conductive medium which is transparent and electrically insulating is a fluid of den^¬ sity 1.5 or more, heat can be transferred and released to low-temperature portions, namely the glass bulb 21 or the cap 23, by means of the convection of the high-thermal ca^¬ pacity fluid, and it is possible to provide a light-emitting diode lamp 20 having an improved heat dissipation effi^¬ ciency .

[0125]

Advantages of characteristic 7

By arranging that the thermally conductive fluid of density

1.5 or more which is transparent and electrically insulating is a perfluorocarbon liquid, it is possible to ensure the electrical safety of the LEDs and wiring, and to provide a light-emitting diode lamp 20 having an improved heat dissi- pation efficiency. Also, the color of the lamp is shifted towards the higher color temperature side and thus appears brighter .

[0126]

Advantages of characteristic 8

By arranging that all of the housing 24 including the glass envelope comprises a glass bulb; that the inside of the glass bulb 21 is filled with an inert gas;

and that the end portion of the glass bulb 21 through which the lead wires 17 leading out from the light-emitting diode unit 10 lead out to the outside of the glass bulb 21 is clo^¬ sed and hermetically sealed, there is no need to form the housing 24 by adhering a resin housing to the base portion of the glass bulb 21, and thus material costs can be reduced and the housing 24 can be produced using existing HID lamp equipment. Also, because the housing 24 is filled with an inert gas and is hermetically sealed, corrosion of metal parts therein such as the lead wires 17 can be prevented, and because the construction is water resistant, outdoor use is also possible. Further, filling with the thermally con- ductive liquid medium can be performed without the need for a special sealing structure that employs a non-metallic seal or the like.

[0127]

Advantages of characteristic 9 By arranging that the light-emitting diode unit 10 is retained by support struts which are implanted in the seal portion side of the glass bulb 21 it is possible to provide a light-emitting diode lamp 20 that is similar in shape to a conventional HID lamp.

[0128]

Advantages of characteristic 10

By arranging that the light-emitting diodes 11 are mounted on substrates, and that the substrates are installed on the side surfaces and the upper surface of the support member 13 it is possible for the shape of the light-emitting diode unit 10 to be similar to that of a cylindrical bulb, and it is possible to provide a light-emitting diode lamp 20 having a light distribution and shape that are similar to those of a conventional HID lamp.

[0129]

Advantages of characteristic 11

By arranging that the light-emitting diodes 11 are mounted directly on the side surfaces and the upper surface of the support member 13 it is possible to omit the light-emitting diode substrate, and is thus possible to produce the light- emitting diode lamp 20 more economically.

[0130]

Advantages of characteristic 12

By arranging that a screw-type metallic cap 23 is fitted to the sealed end of the glass bulb 21 it is possible provide a light-emitting diode lamp 20 which has substantially the sa^¬ me shape as a conventional HID lamp.

[0131]

Advantages of characteristic 13

In combination with a lighting device, the abovementioned light-emitting diode lamp 20 can readily be used as a re^¬ placement in lighting fixtures such as street lights and se^¬ curity lights in which conventional HID lamps have been used, and it is thus possible to provide a lighting fixture such as a street light or a security light having high en^¬ ergy efficiency.

[0132]

*** Second characteristic group ***

Characteristic 1.

In a light-emitting diode lamp 20, a light-emitting diode unit 10 configured by arranging light-emitting diodes 11 on a plurality of surfaces of a support member 13 that has been formed into a three-dimensional shape is installed in a hou^¬ sing 24 formed from a transparent cylindrical bulb and a cap 23 which conducts electricity to the abovementioned light- emitting diode unit 10, and wires leading from the abovementioned light-emitting diode unit 10 are led out to the out- side of the housing 24 via the cap 23.

The abovementioned support member 13 is in the shape of a polygonal prism the bottom surface of which is a regular po^¬ lygon .

The circumcircle of the abovementioned regular polygonal bottom surface is arranged concentrically with the abovemen^¬ tioned cylindrical bulb.

The light-emitting diode lamp 20 is provided with a polygo^¬ nal prismatic light-emitting diode unit 10 comprising a re^¬ gular polygon of which the value of n has been adjusted so as to obtain the desired bulb diameter, where the width w of a side surface of the abovementioned polygonal prism in a direction perpendicular to the axis of the abovementioned polygonal prism, and the distance Ak from the point at which a line extending perpendicular to a side surface of the abo- vementioned polygonal prism from the center of a cross sec^¬ tion through the abovementioned cylindrical bulb intersects the side surface of the abovementioned polygonal prism, to the point at which the abovementioned perpendicularly ex^¬ tended line intersects the inner surface of the abovemen- tioned bulb are fixed, and the regular polygon comprising the bottom surface of the abovementioned polygonal prism is a regular n-sided polygon.

[0133]

Characteristic 2.

A light-emitting diode lamp 20 in which a light-emitting diode unit 10 configured by arranging light-emitting diodes 11 on a plurality of surfaces of a support member 13 that has been formed into a three-dimensional shape is installed in a housing 24 formed from a transparent cylindrical bulb and a cap 23 which conducts electricity to the abovemen^¬ tioned light-emitting diode unit 10, and wires leading from the abovementioned light-emitting diode unit 10 are led out to the outside of the housing 24 via the cap 23, character- ized in that the abovementioned support member 13 is in the shape of a polygonal prism the bottom surface of which is a regular polygon, the circumcircle of the abovementioned regular polygonal bottom surface is arranged concentrically with the abovementioned cylindrical bulb, and light-emitting diodes 11 are arranged in a row in the axial direction of the abovementioned polygonal prism on the side surfaces of the abovementioned polygonal prism.

[0134]

Characteristic 3.

A characteristic is that the abovementioned support member

13 is formed into a three-dimensional shape by bending an integrated sheet, forming a plurality of surfaces.

[0135]

Characteristic 4.

A characteristic is that the width w of a side surface of the abovementioned polygonal prism in a direction perpen^¬ dicular to the axis of the abovementioned polygonal prism is between 5mm and 20mm.

[0136] Characteristic 5.

A characteristic is that the distance Ak from the point at which a line extending perpendicular to a side surface of the abovementioned polygonal prism from the center of a cross section through the abovementioned cylindrical bulb intersects the side surface of the abovementioned polygonal prism, to the point at which the abovementioned perpendicu^¬ larly extended line intersects the inner surface of the abo^¬ vementioned bulb is between 1mm and 6mm.

[0137]

Characteristic 6.

A characteristic is that the plurality of surfaces of the abovementioned support member 13 which has been formed into a three-dimensional shape also function as light-emitting diode element substrates, and the light-emitting diodes 11 are mounted directly on the outer surface of the support member 13.

[0138]

Characteristic 7.

A characteristic is that the light-emitting diode unit 10 is configured by affixing light-emitting diode element sub^¬ strates to the plurality of surfaces of the abovementioned support member 13.

[0139]

Characteristic 8.

A characteristic is that the width of the abovementioned light-emitting diode element substrates is approximately 10mm.

[0140]

Characteristic 9.

A characteristic is that the abovementioned light-emitting diode element substrates are ribbon-shaped flexible sub^¬ strates 12. Characteristic 10.

A characteristic is that the bottom surface of the above- mentioned polygonal prism is a polygon comprising a regular n-sided polygon of which a portion of the vertices has been omitted.

[0142]

Characteristic 11.

A characteristic is that the abovementioned support member 13 is made of metal.

[0143]

Characteristic 12.

A characteristic is that the height of the abovementioned polygonal prism is larger than the diameter of the abovementioned circumcircle .

[0144]

Characteristic 13.

A characteristic is that on the top surface of the above- mentioned heat dissipator there is a polygonal pyramid shape or a polygonal pyramid shape of which the longitudinal sec- tion in the direction of the central axis is trapezoidal, and light-emitting diodes 11 are arranged on each surface of the abovementioned polygonal pyramid shape.

[0145]

Characteristic 14.

A lighting fixture characterized in that the abovementioned light-emitting diode lamp 20 and a lighting device are arranged therein.

[0146]

[0147]

Advantages of characteristic 1

By arranging that the support member 13 is in the shape of a polygonal prism the bottom surface of which is a regular polygon; the circumcircle of the regular polygonal bottom surface is arranged concentrically with the abovementioned cylindrical bulb; and the light-emitting diode lamp 20 is provided with a polygonal prismatic light-emitting diode unit 10 comprising a regular polygon of which the value of n has been adjusted so as to obtain the desired bulb diameter, where the width w of a side surface of the polygonal prism in a direction perpendicular to the axis of the polygonal prism, and the distance Ak from the point at which a line extending perpendicular to a side surface of the polygonal prism from the center of a cross section through the cylindrical bulb intersects the side surface of the polygonal prism, to the point at which the perpendicularly extended line intersects the inner surface of the bulb are fixed, and the regular polygon comprising the bottom surface of the abovementioned polygonal prism is a regular n-sided polygon; it is possible to obtain a light-emitting diode lamp 20 with which components can be standardized and manufacturing proc^¬ esses can be standardized even if the diameter of the glass bulb 21 and the brightness of the light-emitting diode lamp 20 are varied while maintaining as fixed values the width of the side surfaces of the polygonal prism and the distance from the light-emitting diodes 11 arranged on the side sur^¬ faces to the inner surface of the glass bulb 21; with which heat from the light-emitting diodes 11 can be efficiently allowed to escape to the glass bulb 21; which is low-cost and is highly compatible with lighting fixtures; and which has a long operating life.

[0148]

Advantages of characteristic 2

By arranging that the support member 13 is in the shape of a polygonal prism the bottom surface of which is a regular polygon; the circumcircle of the regular polygonal bottom surface is arranged concentrically with the cylindrical bulb; and light-emitting diodes 11 are arranged in a row in the axial direction of the polygonal prism on the side sur^¬ faces of the polygonal prism; the number of side surfaces of the polygonal prism can be readily adjusted, and by obtain- ing a light-emitting diode lamp 20 having the desired bulb diameter it is possible to obtain a light-emitting diode lamp 20 with which components can be standardized and manu^¬ facturing processes can be standardized even if the diameter of the glass bulb 21 and the brightness of the light- emitting diode lamp 20 are varied while maintaining as fixed values the width of the side surfaces of the polygonal prism and the distance from the light-emitting diodes 11 arranged on the side surfaces to the inner surface of the glass bulb 21; with which heat from the light-emitting diodes 11 can be efficiently allowed to escape to the glass bulb 21; which is low-cost and is highly compatible with lighting fixtures; and which has a long operating life.

[0149]

Advantages of characteristic 3

By arranging that in the support member 13, a plurality of surfaces is formed by bending an integrated sheet, it is possible to obtain a light-emitting diode lamp 20 which enhances standardization of components, reduction in the number of components, and standardization of manufacturing pro- cesses.

[0150]

Advantages of characteristic 4

By arranging that the width w of a side surface of the po^¬ lygonal prism in a direction perpendicular to the axis of the polygonal prism is between 5mm and 20mm, the number of side surfaces of the polygonal prism can be readily adjusted in a state in which light-emitting diodes 11 are arranged in a row in the axial direction of the polygonal prism on the side surfaces of the polygonal prism, and by obtaining a light-emitting diode lamp 20 having the desired bulb diame^¬ ter it is possible to obtain a light-emitting diode lamp 20 with which components can be standardized and manufacturing processes can be standardized even if the diameter of the glass bulb 21 and the brightness of the light-emitting diode lamp 20 are varied while maintaining as fixed values the width of the side surfaces of the polygonal prism and the distance from the light-emitting diodes 11 arranged on the side surfaces to the inner surface of the glass bulb 21;

with which heat from the light-emitting diodes 11 can be efficiently allowed to escape to the glass bulb 21; which is low-cost and is highly compatible with lighting fixtures; and which has a long operating life.

[0151]

Advantages of characteristic 5

By arranging that the distance Ak from the point at which a line extending perpendicular to a side surface of the above- mentioned polygonal prism from the center of a cross section through the abovementioned cylindrical bulb intersects the side surface of the abovementioned polygonal prism, to the point at which the abovementioned perpendicularly extended line intersects the inner surface of the abovementioned bulb is between 1mm and 6mm, the light-emitting diode unit 10 can be readily inserted into the glass bulb 21 with a high yield, and it is possible to obtain a light-emitting diode lamp 20 with which heat from the light-emitting diodes 11 can be efficiently allowed to escape to the glass bulb 21, which is low-cost and is highly compatible with lighting fixtures, and which has a long operating life.

[0152]

Advantages of characteristic 6

By arranging that the plurality of surfaces of the support member 13 which has been formed into a three-dimensional shape also function as light-emitting diode element sub- strates, and that the light-emitting diodes 11 are mounted directly on the outer surface of the support member 13 it is possible to omit the light-emitting diode substrate, and is thus possible to produce the light-emitting diode lamp 20 more economically.

[0153]

Advantages of characteristic 7

By arranging that the light-emitting diode unit 10 is configured by affixing light-emitting diode element substrates to the plurality of surfaces of the support member 13 it is possible to make use of an existing generic light-emitting diode element substrate.

[0154]

Advantages of characteristic 8

By arranging that the width of the light-emitting diode element substrates is approximately 10mm it is possible to make use of a more generic light-emitting diode element sub^¬ strate that is already generally available.

[0155]

Advantages of characteristic 9

By arranging that the light-emitting diode element substrates are ribbon-shaped flexible substrates 12 it is pos^¬ sible to make use of a more generic light-emitting diode element substrate that is already generally available.

[0156]

Advantages of characteristic 10

By arranging that the bottom surface of the polygonal prism is a polygon comprising a regular n-sided polygon of which a portion of the vertices has been omitted it is possible to obtain a light-emitting diode unit 10 that is adapted to a particular shape of fixture or a particular light distribu^¬ tion.

[0157]

Advantages of characteristic 11 By arranging that the support member 13 is made of metal, heat generated by the light-emitting diodes 11 can be effi^¬ ciently absorbed and dissipated.

[0158]

Advantages of characteristic 12

By arranging that the height of the polygonal prism is lar^¬ ger than the diameter of the circumcircle heat generated by the light-emitting diodes 11 can be efficiently dissipated.

[0159]

Advantages of characteristic 13

By arranging that on the top surface of the heat dissipator there is a polygonal pyramid shape or a polygonal pyramid shape of which the longitudinal section in the direction of the central axis is trapezoidal, and light-emitting diodes 11 are arranged on each surface of the polygonal pyramid shape, light at the top portion of the lamp can be distrib^¬ uted in all directions.

[0160]

Advantages of characteristic 14

In combination with a lighting device, the abovementioned light-emitting diode lamp 20 can readily be used as a re^¬ placement in lighting fixtures such as street lights and se^¬ curity lights in which conventional HID lamps have been used, and it is thus possible to provide a street light or a security light having high energy efficiency.

[0161]

Also, because the light distribution is not oriented, but the light from the light-emitting diodes 11 is distributed in approximately all directions, the lamp is not only appli- cable to street lights having substantially horizontal lights, which predominantly illuminate a lower surface, but also to base-down and base-up fixtures.

[Explanation of the reference numbers]

[0162] 10 light-emitting diode unit, 11 light-emitting diode, 12 flexible substrate, 13 support member, 14 base portion sup^¬ port strut, 15 axial support strut, 16 linking support strut, 17 lead wire, 18 pyramid, 20 light-emitting diode lamp, 21 glass bulb, 22 flare tube, 23 cap, 24 housing.

Claims

Patent claims [Claim 1]

A light-emitting diode lamp which is provided with a light- emitting diode unit in which light-emitting diodes are mounted on the side surfaces of a prismatic or cylindrical sup^¬ port member,

and a housing having a glass cover which envelops the light emitting surface of the abovementioned light-emitting diode unit and which is arranged inside the light-emitting diode unit,

[Claim 2]

The light-emitting diode lamp as claimed in claim 1, characterized in that a space between the light emitting surface of the abovementioned light-emitting diode unit and the in^¬ ner surface of the glass cover is filled with a thermally conductive medium which is transparent and electrically in- sulating.

[Claim 3]

The light-emitting diode lamp as claimed in claim 2, characterized in that the abovementioned thermally conductive medium is a silicone resin.

[Claim 4]

The light-emitting diode lamp as claimed in claim 2, characterized in that the abovementioned thermally conductive medium is a fluid of density 1.5 or more.

[Claim 5]

The light-emitting diode lamp as claimed in claim 4, characterized in that the abovementioned thermally conductive medium is a perfluorocarbon liquid.

[Claim 6]

The light-emitting diode lamp as claimed in any of claims 1 to 5, characterized in that the abovementioned housing com^¬ prises a glass bulb, the inside of the abovementioned glass bulb is filled with an inert gas, and the abovementioned glass bulb is closed and hermetically sealed by means of a glass bulb end portion through which the lead wires lead out to the outside of the glass bulb.

[Claim 7]

[Claim 8]

The light-emitting diode lamp as claimed in any of claims 1 to 7, characterized in that the abovementioned light- emitting diodes are mounted on substrates,

and the abovementioned substrates are installed on the side surfaces and the upper surface of the abovementioned support member .

[Claim 9] The light-emitting diode lamp as claimed in any of claims 1 to 7, characterized in that the abovementioned light- emitting diodes are mounted directly on the side surfaces and the upper surface of the abovementioned support member.

[Claim 10]

The light-emitting diode lamp as claimed in any of claims 1 to 9, characterized in that fixed to the abovementioned hou^¬ sing is a cap, being a screw-shaped metallic cap, to which lead wires which lead out from the abovementioned light- emitting diode unit are wired.

[Claim 11]

A lighting fixture characterized in that it is provided with a lighting device and the light-emitting diode lamp as claimed in any of claims 1 to 10.