GB2495702A

GB2495702A - Lamp holder

Info

Publication number: GB2495702A
Application number: GB1117527.0A
Authority: GB
Inventors: Lewis Andrew Smith
Original assignee: Cooper Technologies Co
Current assignee: Cooper Technologies Co
Priority date: 2011-10-11
Filing date: 2011-10-11
Publication date: 2013-04-24
Also published as: GB201117527D0

Abstract

A lamp holder 7, 24 for a solid state e.g. LED, lamp 1 has a surface against which a lamp 1 is retained, means, e.g. angled barbs, 22, 23 for locating connection wires 15, 16 from an external device and means, e.g. biasing tabs, 26, 27 for urging stripped parts 21 of the wires 15, 16 into electrical connection with electrodes 3,4 of the solid state lamp 1. The use of biasing tabs 26, 27 mean no soldering is required. An additional invention relates to the lamp holder 7, 24 having an orifice 25 through which lights is emitted, the orifice 25 being surrounded by a number of facets (42, fig 4).

Description

INTELLECTUAL

. . PROPERTY OFFICE Applicalion No. GBI1I.7527.0 RTIIVI Rae:6 February 2012 The following term is a registered trademark and should be read as such wherever it occurs in this document: Citizen Intellectual Property Office is an operaling name of Ihe Patent Office www.ipo.gov.uk

I

Lamp Holders This invention relates to lamp holders. In particular, it relates to a lamp holder for retaining a solid state light source, such as an LED light source, within lighting equipment.

LED and other solid state light sources are becoming more and more common for use in lighting installation, including emergency lighting and other lighting applications.

Solid state lighting is very efficient and has long life. A lamp holder is used to locate an LED lamp in the correct position in a fighting installation and to provide connections to an electronic driver unit via wire conductors. The lamp holder securely retains an LED source, or lamp, in such a way that heat transfer to a heal sink is assured.

Conventional lamp holders include terminal parts, typically of metal, which are located such that wires from an electronic driver make connection with the terminal and the terminal makes connection with the in-built terminals on a solid state light source device.

Alternatively, the wires from the driver can be directly soldered to the terminals on the solid state light source. This adds a considerable cost to the electrical connection to the solid state light source and can also lead to failures and increased manufacturing lead times.

A standard lamp or LED, without any optical control, generally emits light in a Lambertian distnbution (equal light emitted in a 360 degree radius). By putting a lamp holder in front of the LED array, the body will act upon the distribution in a negative manner. Presently-available lamp holder designs offer little in the way of optical control (ie control of the distribution of light rays) to improve this.

The present invention arose in an attempt to provide an improved lamp holder for LED lamp devices.

According to the present invention in a first aspect there is provided a lamp holder for a solid state lamp, comprising a surface against which a lamp is retained, means for locating a connection wire from an external device and means for urging a bare part of the wire into electrical connection with an electrode of the solid state lamp.

The solid state lamp is preferably an LED lamp.

The lamp holder may comprise a first part having a first surface against which the LED lamp is retained, one or more through holes, means for locating one or more wires such that a bare part of the or each wire Hes generally in register with the or each through-hole, which is in turn generally in register with an electrode on the lamp, and a second part adapted for affixing with the first part and having means for urging at least part of the located stripped part of the wire into contact with the lamp electrode.

Preferably, the holder comprises a base part to which a lamp is attachable, and a cover part, the cover part having protruding means positioned to urge a bare part of the wire 1 5 into direct electrical connection with an electrode of the solid state lamp. The cover part is most preferably made as one complete moulding with no metal terminals.

The locating means is preferably arranged such that a bared end part of the wire can be located in an appropriate position.

The means for urging the stripped part of the wire against the terminal may be one or more tabs.

The tabs may be formed by pushing apart of the second part outwardly from the surface thereof.

The location means may comprise one or more channels. These may be. at least, partly formed by upturned walls.

Usually, but not necessarily, two sets of location means. wire connections and urging means will be used.

Barb means may be provided to retain the wires.

lii a further aspect. the invention provides a method of securing and electrically connecting an LED lamp, having one or more LEDs and electrode means, to a lamp holder, comprising mounting the LED lamp to the lamp holder and causing part of the lamp holder to urge exposed conductive parts of connection wires from external device into electncal contact with the electrode means.

In a yet further aspect, the invention provides a lamp holder for a solid state lamp, having an orifice for receiving the light emitting part of the lamp, the orifice having a peripheral surface which is shaped to control the light distnbution from the lamp to obtain a substantially Lambertian distribution.

The surface may be sloped and/or be faceted.

This serves to reflect the rays in a controlled fashion, preferably to maintain a Lambertian distribution and facilitates control of the emitted light.

Embodiments of the invention will now be described, by way of example only. with reference to the accompanying schematic drawings, in which: Figure 1 shows an exploded view of a lamp holder and lamp; Figure 2 shows parts of Figure 1 partially assembled; Figure 3 shows an assembled structure; Figure 4 shows a perspective cross-section along IV-1Y of the cover of Figure 3; Figure 5 shows a cross-section along P'/-fV; Figure 6 shows the cross-section of an assembled structure; and Figure 7 shows a smaller scale view of Figure 6.

Referring to Figure 1. a lamp holder assembly for holding an LED lamp is shown.

The LED lamp in this case comprises an array of individual LEDs mounted on a substrate.

For example, the Citizen CL330-MC26LI-C LED lamp has one hundred and forty four LEDs and the Citizen CL-L350-MC31L1-E5 has one hundred and sixty eight LEDs arranged in a 12 x 14 array. These are arranged on an LED iarnp body 1 within a generally central region thereof and are covered by a resin layer 2. The LEDs can then illuminate though the resin layer 2. The LED body includes two electrodes 3, 4 which are electrically connected to the LED array and mounting holes 5, 6 for connecting to a lamp holder or to other apparatus.

The lamp holder is provided in two pails, each made from a plastics material. Any convenient plastics material may be used for this.

A lamp holder base part 7 includes a lower surface to which the LED i can be attached by means of separate fasteners 8, 9 mounted through respective through holes 10 and 11 in the lamp holder base 7 which are positioned in register with holes S and 6 in the LED. Many different types of fasteners may be used such as screws, bolts, pins and so on.

These clamp the LED to the bottom face of the lamp holder base 7. The lamp holder base 7 includes a central orifice 12 which receives the resin part 2 and therefore the LED array of the lamp I and allows the array of individual LEDs to illuminate through it.

The LED base includes two guide channels 13 and 14 for receiving respective wire conductors 15 and 16 for connecting the LED to an electronic driver unit (not shown).

These guide channels are formed by walls such as wall 17 which, in this embodiment, are generally perpendicular to the plane of the lamp holder base 7 and protrude outwardly from the surface of the base part 7. At an end portion of each of the guides 13 and i4 there is an end wall 18, 19 and at least the end portion, in this embodiment, is open at the top and bottom, thus this is in effect a through hole. In other embodiments, only the bottom may be open. for example. This end part leading up to end wall 18, 19 is for receiving a stripped (bare) end part of the wire conductor 15 and 16. As is shown most clearly in Figure 2, where the bared portions are shown are 20 and 21. These pails are located such that, when the LED is in position against the lower face of the lamp holder base, they are in register with the electrodes (3 and 4) of the electrode. In this way, the stripped parts 20 and 21 overlie, and can be pushed into electrical contact with, the electrodes of the LED.

In many embodiments, the whole of each guide channel is open at the top and bottom (ie the top and bottom surfaces of the lamp holder base) but in others it may only be open in the region where a stripped (bare) part of wire conduction is to lie.

Although it is preferable to have the bared portion of the wires at their ends, they could of course be in a position anywhere along the wire and the wire will then be located by the guide means in such a position that wherever the bared por ion is, this portion is generally in register with the electrodes of the LED to be attached to the connector, such that the bared portions can make electrical contact with the electrodes.

The guides therefore serve to secure and locate the bare wire in a region generally in register with the electrodes of the LED (when it is attached in its norma' position) such that they can be urged into electrical contact with the respective electrodes.

Each guide channel also includes one or more opposed pairs of angled barbs 22, 23 which serve to securely hold a conductor wire in place. More sets of barbs may be provided in each channel or alternative means may be used to securely locate a conductor.

Alternatively, the guide channels may be sized to hold the conductor (with dadding) securely in place without the need of any barbs, although most embodiments will use barbs or similar mechanisms.

The lamp holder includes a second part in the form of a cover 24. This includes a central orifice 25 of similar bottom diameter to the orifice 12 in lamp holder base 7 and intended to overlie the resin part 2 and therefore LED array of the LED lamp to illuminate a room or other location. This orifice does not have a circular inner peripheral surface but instead the surface is formed of a plurality of flat facets, and is sloped such that the orifice is wider at its edge 40 which is to be proximal to the LED, and narrower to its distal edges 41 as is shown dearest iii Figure 5. In one example there are 24 facets. Other numbers may be used.

The lamp holder cover also includes two tabs 26 and 27 which are pre-moulded to depend downwardly from the surface of the cover (when in the disposition shown in Figure 1). This is, in use, they have a free end which extends towards the lamp holder base 7 and therefore towards the LED 1 when this is mounted to the base 7. These are provided at locations such that when the cover 24 is affixed to the base 7 the tabs 26 and 27 overlie the end regions of the guides 13 and 14 such that they can directly act upon the bed end portions of the wired conductors 15 and 16.

The cover includes a clip arrangement, which may take many forms, and in this case includes clip parts 28 and 29 (and 30, 31 not shown in Figure 1) which cooperate with clips 32. 33. 34 and 35 on the base 7 in order to clip and retain the cover in place. There may of course be more or less clips that this and alternative means maybe used to securely attach the cover to the base. It is preferably that a simple clip-type mechanism is used such that the cover can easily be removed when necessary, although more permanent fasteners may be used if desired.

Assembly of the structure with an LED lamp will now be described.

Firstly, the LED 1 lamp is retained in place by the lamp holder base by means of the fasteners 8 and 9. A positive multi-strand conductor 15 is then fed through the guide channel 13 starting at a stripped or bare end 20. It is fed through the guide channel until the stripped ends abuts up against the end wall 19. The conductor may then be pushed down into the guide channel to ensure that the angled barbs 22 are securely holding the conductor in place.

A negative multi-strand conductor 16 is then fed through guide channel 14 starting at the stripped end 20. This stripped end is placed against the end wall 18. The conductor is then pushed down into the guide channel to ensure that the angled barbs 23 are way off said angled barbs.

With both conductors securely and correctly located, the lamp holder cover is clipped in place using clips/catches 28 to 34.

This causes the moulded spring tabs 26 and 27 to force and retain the stripped or bare end of the conductor securely against the respective electrodes of the LED (3 and 4).

Thus, the tabs 26 and 27 urge the bare ends of the conductor into electrical contact with the terminals or electrodes on the LED. No other action is necessary and in particular no soldering is necessary and no additional metal or other conductive terminals need be provided on the lamp holder parts themselves. The lamp holders can therefore simply be made of moulded plastics materials.

In the embodiment shown, both wiles are shown as entering base I from the same direction and the same side. Channel 13 is therefore of significantly less length than guide channel 40 in order that the respective end parts of channels 13 and 14 lie in the correct position with respect to the electrodes of an LED assembly. However, the guide channels maybe otherwise disposed and in one embodiment, not shown, the guide channels may start at generally diametrically opposite regions of the base and be generally symmetrically arranged. Many other configurations will be apparent.

The tabs 26 and 27 will be pre-moulded to have a distal end which depends away from plane of the cover. In other embodiments, those may be separate parts which are attached to a lamp holder cover but the simplest and most effective method is considered to be one in which they are moulded integrally with the rest of the cover.

A heat sink (not shown) will generally be used with an LED lamp and this will be mounted to sit on the other side of the LED lamp ito the side which faces the lamp holder assembly. Thus, the LED lamp will be effectively urged towards the heat sink and to make good contact made with it for the most efficient heat transfer. The LED lamp is urged towards this by virtue of the two retaining screws which hold the LED to the heatsink.

The conductors are most preferably multi-strand conductors.

Figure 3 shows an assembled construction in which the cover 24 is mounted and clipped over the base 7. The LED itself is not shown in this figure because it is obscured but the multi-strand conductors 15 and 16 leading to it are shown.

As described, the internal surface of the orifice 25 of the lamp holder cover 24 comprises a plurality of planar facets, as is shown in the figures, particularly Figures 4 and 5. Figure 4 shows a cross-sectional perspective view obtained by nominally cutting the cover along line tv-tv of Figure 3 and Figure 5 shows a cross-sectional view. As shown most clearly in Figure 5, the internal surface is also stoped such that it increases in diameter from a first edge 40 which is proximal to an LED or when the cover is assembled, and is in fact formed by an inner flange which abuts against the top surface of the LED substrate, to a distal edge 41. Typically, this slope angle is 10 degrees from the plane which is normal to the plane of the top surface 43 of the cover. The planar facets 42 are part of the single element moulded cover, although in other embodiments they may be formed of separate planar elements which are affixed or adhered to an inner surface of the orifice.

Figure 4 shows in more detail the structure of parts of the lamp holder including the flange part 44 forming the orifice 25 and the walls of the lamp holder part. Figures 4 and 5 also show, partly obscured, one of the tab mechanisms 26 which acts to directly push the wires against the electrodes of the LED, without any accompanying metal contacts or solder.

The angle of 10 degrees is not essential and other angles may be used. They may be at angles from 0 degrees (vertical) to 90 deRrees.

Figures 6 and 7 show schematically some light traces of light rays emitted by the LED assembly I when the cover is assembled. Note that Figures 6 and? are inverted compared to the remaining figures. Figure 6 is a larger scale representation than Figure 7.

The figures show cross-sections of the lamp holder and LED assembly showing ray trace calculations R1. Each of these elements R is a calculated ray of light which has been emitted from LED which either emits straight out the front of the assembly (such as RI) or which is reflected off one of the faceted surfaces 42, such as ray R2. The angle and number of faces can be chosen in order to try to maintain a Lambertian (distribution of rays). This makes it much easier to control light from the device. An external reflector may be used for example but this receives light substantially equally over a 360 degree angle the light emissions is easy to control. figure 7 is a smaller scale view of Figure 6 showing the rays extending outwardly more and illustrating the generally substantially equal distribution of the rays over 360 degrees.

Claims

<claim-text>Claims 1. A lamp holder for a solid state lamp, comprising a surface against which a lamp is retained, means for locating a connection wire from an external device and means for urging a bare part of the wire into electrical connection with an electrode of the solid state lamp.</claim-text> <claim-text>2. A lamp holder as claimed in Claim 1, comprising a base part to which a lamp is attachable, and a cover part, the cover part having protruding means positioned to urge a bare part of the wire into electrical connection with an electrode of the solid state lamp.</claim-text> <claim-text>3. A lamp holder as claimed in Claim 1 or Claim 2, wherein the locating means comprises one or more guide channels adapted to confine bare pails of wires to a specific region where they can be urged into electrical connection with one or more electrodes of an 1 5 attached solid state lamp.</claim-text> <claim-text>4. A lamp holder as claimed in Claim 3, wherein the or each guide channel is provided on a base part of the holder.</claim-text> <claim-text>5. A lamp holder as claimed in Claim 3 or 4, wherein each guide channel is open at at least the face to which a lamp is retained, and at least in said specific region, to enable the bare part of the wire to make direct electncal connection with an electrode of a lamp.</claim-text> <claim-text>6. A lamp holder as claimed in Claim 3, 4 or 5, wherein two channels are provided, for connection of two respective connection wires to two respective dectrodes.</claim-text> <claim-text>7, A lamp holder as claimed in any of claim 2 to 6, wherein the protruding means comprise tabs moulded to have a distal portion which protrudes toward the base pail when the cover is attached thereto. ii</claim-text> <claim-text>8. A lamp holder as claimed in any of Claims 2 to 7, where the or each guide channel is formed by protruding walls.</claim-text> <claim-text>9. A lamp holder as claimed in any preceding claim, including a pair of guide channels, both beginning the same side of the lamp holder.</claim-text> <claim-text>10. A lamp holder as claimed in any of Claims I to 9, including a pair of guide channels each beginning at respective opposite sides of the lamp holder.</claim-text> <claim-text>11. A lamp holder as claimed in any preceding claim, having a cover part, the cover part having an orifice through which light from the lamp is emitted, wherein the orifice is shaped to optical control the emitted light.</claim-text> <claim-text>12. A lamp holder as claimed in any preceding claim, wherein the orifice has an inner surface which is faceted, each facet being at a predetermined angle relative to the normal axis of the lamp.</claim-text> <claim-text>13. A lamp holder as claimed in Claim 12, wherein the angle is 10 degrees.</claim-text> <claim-text>14. An LED lamp assembly comprising an LED lamp mounted to a lamp holder as claimed in any preceding claim, wherein the LED lamp comprises electrodes located relating to the or any lamp holder such that the electrodes are positioned in places where a bared wired is urged into electrical contact with them by part of the holder.</claim-text> <claim-text>15. An LED lamp holder or lamp holder assembly as claimed in ally preceding claim, wherein no soldering is provided.</claim-text> <claim-text>16. A method of securing and electrically connecting an LED lamp, having one or more LEDs and electrode means, to a lamp holder, comprising mounting the LED lamp to the lamp holder and causing part of the lamp holder to urge exposed conductive parts of connection wires from external device into electrical contact with the electrode means.</claim-text> <claim-text>17. A method as claimed in Claim 13, wherein the urging means comprises tabs formed on a cover part of the lamp holder which, when attached to a base part, act upon parts of connection wires which are located at a specific position to urge these into electrical contact with the electrode means.</claim-text> <claim-text>18. A method as claimed in Claim 16, wherein the cover includes an onfice, through which light from the lamp is emitted, and which is shaped to optically control the light to a substantially Lambertian distribution.</claim-text> <claim-text>19. A method as claimed in Claim 18, wherein the orifice comprises a wall having a plurality of planar facets at a predetermined angle to the normal axis of the lamp.</claim-text> <claim-text>20. A lamp holder for a solid state lamp, having an orifice for receiving the light emitting part of the lamp, the orifice having a peripheral surface which is shaped to control the light distribution from the lamp to obtain a substantially Lambertian distribution.</claim-text> <claim-text>21. A lamp holder as claimed in Claim 20, wherein the orifice comprises a wall having a plurality of planar facets at a predetermined angle to the normal axis of the lamp.</claim-text> <claim-text>22. A lamp holder substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.</claim-text> <claim-text>23. An LED lamp assembly mounted to a lamp holder substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.</claim-text> <claim-text>24. A method of securing a solid state lamp to a lamp holder substantially as hereinbefore described, with reference to the accompanying drawings.</claim-text>