WO2003088421A1

WO2003088421A1 - Mounting of led devices to circuit board or ribbon

Info

Publication number: WO2003088421A1
Application number: PCT/AU2003/000414
Authority: WO
Inventors: David Field Showers; Malcolm Wesley Oldis; Kenneth Robert Goddard
Original assignee: Showers International Pty Ltd
Priority date: 2002-04-05
Filing date: 2003-04-07
Publication date: 2003-10-23

Abstract

An assembly of an electronic circuit device (30) and an electrical circuit board or ribbon (40) wherein the electronic circuit device has at least two contact pins (33) depending therefrom and is mounted at an edge of the circuit board or ribbon. The at least two contact pins are bent in towards each other, then outwardly with respect to the electronic circuit device so as to define end portions (134) that are separated by the circuit board or ribbon. At least one of the end portions is conductively attached to the circuit board or ribbon.

Description

Mounting of LED Devices to Circuit Board or Ribbon

Field of the invention

This invention relates generally to the mounting of electronic circuit devices such as light emitting diodes to circuit boards and ribbons.

Background Art

In recent times, a new light source has emerged in the field of illumination, ie solid state lamp devices, most commonly light emitting diodes (LEDs). These have been widely employed for many years for small scale indicator and display purposes but their development for illumination applications has become feasible as the light output and uniformity of LEDs has been progressively enhanced. For these applications LEDs have become commercially available in a variety of packages or sets in which rigid substrates mount different numbers and types of LEDs in varied arrays, as well as in individual packages of single LEDs.

International patent publication WO99/06759 discloses a modular strip lighting system in which linear arrays of LEDs are mounted on printed circuit board (pcb) substrates within elongate part tubular housings. These housings are attached in turn to backing rails and thereby employed to highlight commercial or building features such as sign boards and external ridges or edges. The housings are formed in a material which disperses the LED light so that the housings glow as a strip or line of light.

The present applicant's international patent publication WO 01/91090 extends the use of solid state lamp devices to illuminated signs. In this arrangement, an array of solid state lamp devices such as LEDs backlight an overlying translucent sheet and thereby cause illumination of sign content provided on, or in conjunction with, the sheet.

International patent publication WO 03/019506 discloses an illuminated sign or display apparatus that includes support structure, an elongate opening in the support structure, and an elongate translucent body mounted in the opening. Means is provided for retaining a plurality of spaced light sources at a first side of the support structure in proximity to the elongate body, whereby the body and the light sources are mutually arranged so that the light sources when activated cause the body to glow and to appear, at a second side of the support structure, as a strip or line of light. In a preferred arrangement, the light sources are an array of light emitting diode devices, commercially known as LED packages, mounted at the edge of a circuit board or ribbon.

Japanese patent publication 09-330049 discloses a decorator, printed circuit board (PCB) strip with LED devices mounted at spaced intervals along an edge of the strip. The respective contacts of those LED devices extend along opposite sides of the strip and are electrically connected to circuit components printed on the strip.

A known wedge "globe" has a single LED projecting from the short edge of a rectangular wafer of PCB with its contacts extending along one side of the PCB and soldered to the printed circuit. The wafer of PCB also had electrical contact pads to allow the item to be substituted for conventional wedge-fitted incandescent globes.

In these prior arrangements in which LED devices or packages project from an edge of a circuit board or ribbon, contact pins projecting from the devices are typically not bent or deflected in any way for fear of damaging the LED encapsulation or breaking electrical contact paths. It is an object of this invention to provide a pin configuration that facilitates edge mounting, and apparatus for achieving the configuration without compromising the integrity of the LED device.

In particular aspects, it is an object of the invention to provide improved arrangements for mounting and positioning electronic circuit devices that, when adapted to the mounting and positioning of solid state lamp devices, facilitate their application to illuminated signs and displays and to lamp assemblies. Summary of the Invention

In a first aspect, the invention proposes edge mounting of electronic circuit devices by arranging their contact pins to be bent in towards each other, then outwardly with respect to the electronic circuit device so as to define end portions that are separated by the circuit board or ribbon, at least one of the end portions being conductively attached to the board or ribbon.

The invention accordingly provides, in its first aspect, an assembly of an electronic circuit device and a circuit board or ribbon, wherein the electronic circuit device has at least two contact pins depending therefrom and is mounted at an edge of the circuit board or ribbon with said at least two contact pins bent in towards each other, then outwardly with respect to said electronic circuit device so as to define end portions that are separated by the circuit board or ribbon, at least one end portion being conductively attached to the board or ribbon.

Preferably, the end portions of the contact pins include respective first segments that engage the circuit board or ribbon, and respective second segments that are splayed away from each other and that each lie between the first segment and the tip of the respective pin.

In an advantageous application, the electronic circuit device is a solid state light source, eg. a light emitting diode device. There may advantageously be an array of the devices arranged along the edge of the board or ribbon.

In one application, the electronic circuit device is a single light emitting diode device, and said circuit board or ribbon includes a pair of electrical contacts disposed to engage respective corresponding electrical contacts when the mount is pushed between opposed formations defining a socket for receiving the circuit board or ribbon.

The circuit board or ribbon may be a rectangular wafer, in which case the circuit device may be mounted at a shorter edge of the wafer. In the first aspect of the invention, there is also provided an array of solid state light devices, for example light emitting diode devices, in which the light devices are fixed along and project laterally from an edge of a circuit board or ribbon with their central axes generally parallel to the plane of the board or ribbon and at least two electrical contact pins, of each light device in operative contact with the circuit on the board or ribbon, wherein said contact pins are bent in towards each other, then outwardly with respect to said light device so as to define end portions that are separated by the circuit board or ribbon, at least one of the end portions being conductively attached to the circuit board or ribbon.

In a second aspect, the invention provides apparatus for bending a pair of contact pins of an electronic circuit device, eg a solid state light device, to facilitate mounting of the device, including:

a seat for stably holding the electronic circuit device with the pins protruding therefrom;

means for clamping the electronic circuit device at the points where the pins protrude from a body portion of the device;

separation structure locatable between the pins; and

respective bending jaws moveable to bend the pins towards the separation structure and co-operable with the separation structure to form the pins in a configuration in which the pins are bent in towards each other, then outwardly with respect to said body portion so as to define end portions between which a circuit board or ribbon may be disposed.

Brief Description of the Drawings

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic representation of a simple sign apparatus incorporating LEDs and displaying the letter "A"; being apparatus disclosed and claimed in international patent publication WO 03/019506;

Figure 2 is a fragmentary isometric sectioned view of part of the apparatus of Figure 1 ;

Figure 3 illustrates a modified embodiment and also shows, in a fragmentary fashion, the mounting of the LEDs to a flexible circuit ribbon;

Figure 4 is another view of an array of LEDs along an edge of a flexible circuit ribbon;

Figure 5 is a fragmentary cross-section showing an alternative pin configuration for fixing each LED to a side edge of a circuit ribbon in accordance with the first aspect of the present invention;

Figure 6 is a fragmentary cross-section of an embodiment of solid state lamp device according to the first aspect of the invention, depicted in situ serving as a "plug-in" replacement element in an electrical light socket;

Figure 7 is a front view of the device illustrated in Figure 6;

Figure 8 is a diagrammatic isometric view of apparatus comprising a tool for bending the pins of an LED package into the configurations shown in Figures 5 and 6, which apparatus is an embodiment of the second aspect of the invention;

Figures 9A, 9B and 9C are corresponding schematic cross-sections depicting stages in the operation of the tool of Figure 8; and

Figure 10 is a fragmentary view of a portion of the tool including the LED package after its pins have been configured by the tool. Description of Preferred Embodiments

The sign apparatus illustrated in Figure 1 , disclosed in applicant's co- pending international patent publication WO 03/019506, is diagrammatically represented as a simple sign displaying an upper case "A" on a plain background. The plain background is provided by a cover panel 12 for an open-topped housing 14 in the form of a generally rectangular box. Although not shown in Figure 1 , this housing would typically also include one or more fluorescent tubes, or possibly suitable incandescent lamps, for backlighting panel 12. Panel 12 would typically be a translucent or partially transparent polycarbonate sheet of a selected colour.

The character "A" is provided as an exemplary embodiment. It is defined by three elongate, transverse, translucent and preferably light dispersive solid bodies 16 (separately indicated in Figure 1 as 16a, 16b, 16c) mounted in matching elongate openings 18 in the support structure provided by panel 12. Bodies 16 comprise extrusions of a selected polyvinyl chloride material of uniform cross section of the form shown in Figure 2. The principal components of this cross section are an outer portion 20 of generally cylindrical appearance, mid-portion 22 which lies in opening 18, and inner portion 24. Portion 24 defines, along the rear face of the extrusion, a longitudinally extending recess 26 that snugly receives, at spaced intervals, LED packages 30. Packages 30 are retained by return lips 25, which may typically be resiliently deflectable to allow packages 30 to be snapped into place.

Inner portion 24 is also dimensioned to fit through opening 18 and the extrusion is held in place in the opening by the co-operation with panel 12 of respective flared ribs 28 that engage the outer surface of the panel and deflectable flanges 29 that are inclined so as to each deflect into a respective matching depression 27 in the sides of the extrusion as it is pushed through the opening 18 from the outside of panel 12. These flanges 29 snap back under panel 12 when the extrusion reaches its desired location and the panel 12 is gripped between ribs 28 and flanges 29. LED packages 30 are commercially available packages comprising a body or base 32, four depending contact leads 33 arranged in a square array, and the actual light emitting diode 34. Suitable LEDs include the Super Flux, High Flux or 5mm LEDs supplied by LumiLeds or Agilent Technologies, but any other appropriate LED may be employed. LEDs 34 seat snugly in a longitudinally extending groove or channel 36 in the surface of recess 26.

Electrical power for activating LEDs 34, eg 5 volts DC, is delivered from a power pack 42 to the array of LEDs along extrusion 16 via a printed circuit board (pcb) or circuit ribbon 40. A preferred arrangement that utilises edge mounting of the LEDs to a flexible circuit ribbon, is detailed in Figures 3 to 5. The packages 30 are fixed along and project laterally from an edge of the ribbon, rather than being surface mounted as is the conventional arrangement, with their central axes generally parallel to the plane of the ribbon and their pins conductively attached to respective faces of the ribbon. In one arrangement, depicted in Figures 3 and 4, the electrical contacts or legs 33 of the LED packages are soldered to contact pins 96 projecting from the ribbon surface and are thereby in operative electrical contact with the circuit 94 on ribbon 40.

A pin configuration in accordance with the present invention is shown in Figure 6: the pins of each opposed pair of pins 33" are bent in towards each other, then outwardly with respect to body or base 32. The pins include aligned intermediate portions 133 generally parallel to but spaced from body or base 32, curving into end portions 134. These end portions 134 are overturned and lie over intermediate portions 133. End portions 134 include first segments 136 that contact or almost contact but are separable to receive and grip the circuit ribbon to which they are then soldered, and second segments 137 that are splayed or divergent away from each other. Segments 137 each lie between the first segment 136 and the tip 138 of the respective pin. The splaying facilitates location relative to the ribbon in automatic assembly equipment.

The solid state lamp device 20 illustrated in Figures 6 and 7 comprises an assembly of LED package 230 fixed at the edge 241 of a mount for the LED package in the form of a rectangular circuit board wafer 240. Wafer 240 is shaped and dimensioned to be pushed into a wedge socket 250 of a kind conventionally adapted to receive an incandescent globe. Socket 250 has two pairs 252 of opposed spring metal contact legs 253, 254 for delivering electrical current to the globe: in this case, wafer 240 has, on one of its faces, respective deposits 242 of electrically conductive material that are positioned to serve as electrical contacts for engaging the respective socket contact legs 253, 254 when the wafer is pushed into socket 250.

As before, LED package 230 is a commercially available package comprising a body or base 32, four depending contact legs or pins 33 arranged in a square array when viewed in plan, and the actual light emitting diode 34. Suitable LEDs may typically be the Super Flux, High Flux or 5mm LEDs supplied by LumiLeds or Agilent Technologies, but any other appropriate LED may be employed.

Wafer 240 carries an electrical circuit 245 for delivering electrical current to

LED 34. This current includes, as well as contact deposits 242, an inductive and a single chip switch mode regulator 244 for converting an AC or DC input at contacts 242 over a range of voltages, eg 0-24, to the correct voltage (eg 5 volts) and polarity for LED 34. Alternatively or additionally the circuit may include a bridge rectifier and one or more appropriate resistances and/or capacitances.

LED package 230 is fixed to circuit board wafer 240 in an edge mounted configuration as illustrated, rather than being surface mounted as is the conventional arrangement, with its central axis generally parallel to the plane of the wafer and its pins 33 in pairs 35 for the respective terminals of LED 34. Pins 33 extend over the respective faces of the wafer. The pins of each opposed pair 35 of pins 33 are bent in towards each other, then outwardly with respect to body or base 32. The pins include aligned intermediate portions 133 generally parallel to but spaced from body or base 32, curving into end portions 134. These end portions include first segments 136 that contact or almost contact but are separable to receive and grip wafer 40, and second segments 137 that are splayed or divergent away from each other. Segments 137 each lie between the first segment 136 and the tip 138 of the respective pin.

On the one face of the wafer, both pins engage and are electrically connected to electrically conductive seats 246 by solder 247. Wafer 240 is effectively sandwiched between the respective pairs of LED pins while the splaying facilitates location relative to the wafer in automatic assembly equipment.

A particularly advantageous field of application of the embodiment of Figures 6 and 7 is the low voltage lamps that are used to illuminate push-buttons or indicator elements on a wide variety of equipment including by way of example only, gaming machines, elevator user interfaces or interactive consoles. The need to promptly replace failed incandescent globes is a major maintenance issue with such equipment: the invention allows the provision or in situ substitution of an LED "globe" of much longer life, with consequent savings in maintenance costs.

An apparatus 500 comprising a tool suitable for forming the pin configuration of Figures 6 and 7 is illustrated in Figures 8 to 10 and constitutes an embodiment of the second aspect of the invention. This apparatus is shown as a manually operable tool for processing the LED packages one-by-one but it will of course be understood that the principles of the apparatus can be readily incorporated into an automated apparatus with continuous indexed feed and recovery.

The apparatus 500 includes base structure 502 that houses a seat 510 for stably holding an LED package with the pins protruding upwardly. Base structure 502 also defines tracks 504 for respective reciprocably moveable bending jaws 520 to opposite sides of seat 510, a gudgeon 530 for pivotally mounting an upstanding lever 532 having a cantilevered clamp plate 534, a separation structure 536 in the form of a vertical aligned partition 538, and an ejection ring 540.

Seat 510 has a square recess 512 dimensioned as to side length and depth to snugly and firmly receive the body or base 32 of an LED package 30. At the centre of recess 512 is a circular hole to locate the protruding LED 34 itself. When lever 532 is brought down from the withdrawn position shown in Figure 8 to the operational position shown in Figure 9A, (in which its outer end is guided between uprights 533) clamp plate 534 firmly contacts the rear surface of package body or base 32 and in particular, by having a width that is a close tolerance between the two pairs of pins 33, clamps the LED package at the points 535 where the pins protrude from the body or base 32. This clamping action protects the pins 33, the body or base 32 and their interface region from damage during the subsequent bending operation.

In the operational position of lever 532, separation partition 538 locates midway between the pins 33 but with its lower edge spaced from clamp plate 534

(Figure. 9A). Bending jaws 520 may now be moved inwardly (eg. by operating crank drives 522) to move the jaws inwardly as shown in Figures 9B and 9C. The bottom surfaces 521 of the jaws are just above the plane of the top face of clamp plate 534. Pins 33 are bent over the side edges of the clamp plate towards contact with separation partition 538 (Figure 9B). Further inward movement of the jaws causes the pins to return bend in end portions 134. By virtue of the back angled forward surfaces 524 of jaws 520, the pins 33 are then configured to include straight intermediate portions 133 parallel to but spaced from body or base 32 by the width of clamp plate 534, curving around the nose edges 526 of jaws 520 into splayed out-turned end portions 134: these end portions contact or almost contact in their curved region and the splaying is encouraged by the intrusion of partition

538.

Crank drives 522 may be operated by rotating base structure 502 without translating pivot points 508.

The formed package is recovered by raising lever 532: during this action, ejection ring 540 pushes the package off the end of the cantilevered clamp plate 534 by reason of the ring's eccentric mounting with respect to the hinge axis of the lever. The apparatus illustrated in Figures 8 to 10 allows the pin configuration of Figures 5 and 6 to be formed without damaging the pins or the body of the LED package, and especially protects the body region where the pins exit the package.

Claims

An assembly of an electronic circuit device and an electrical circuit board or ribbon, wherein the electronic circuit device has at least two contact pins depending therefrom and is mounted at an edge of the circuit board or ribbon with said at least two contact pins bent in towards each other, then outwardly with respect to said electronic circuit device so as to define end portions that are separated by the circuit board or ribbon, at least one of the end portions being conductively attached to the circuit board or ribbon.

An assembly according to claim 1 wherein said end portions of the contact pins include respective first segments that engage the circuit board or ribbon, and respective second segments that are splayed away from each other and that each lie between the first segment and the tip of the respective pin.

An assembly according to claim 1 or 2 wherein said electronic circuit device is a solid state light device.

An assembly according to claim 3 wherein said solid state light device is a light emitting diode device.

An assembly according to any one of claims 1 to 4 wherein there is an array of said electronic circuit devices arranged along said edge of the board or ribbon.

An assembly according to any one of claims 1 to 4 wherein said electronic circuit device is a single light emitting diode device, and said circuit board or ribbon includes a pair of electrical contacts disposed to engage respective corresponding electrical contacts when the mount is pushed between opposed formations defining a socket for receiving the circuit board, or ribbon. An assembly according to any one of claims 1 to 4 and 6, wherein said circuit board or ribbon is a rectangular wafer.

An assembly according to claim 7, wherein said circuit device is mounted at a shorter edge of said wafer.

A lamp assembly comprising;

means having opposed formations defining a socket, said means further including respective electrical contacts associated with said socket; and

a complementary lamp component configured to be received into said socket, which lamp component comprises a circuit board or ribbon having an edge at which is mounted a solid state lamp device;

wherein said lamp device has at least two contact pins bent in towards each other, then outwardly with respect to said solid state lamp device so as to define end portions that are separated by the circuit board or ribbon, at least one of the end portions being conductively attached to the circuit board or ribbon; and

wherein said circuit board or ribbon includes a pair of electrical contacts disposed to engage said electrical contacts associated with said socket when the lamp component is received into said socket.

An array of solid state light devices in which the light devices are fixed along and project laterally from an edge of a circuit board or ribbon with their central axes generally parallel to the plane of the board or ribbon and at least two electrical contact pins of each light device in operative contact with the circuit on the board or ribbon, wherein said contact pins are bent in towards each other, then outwardly with respect to said solid state light device so as to define end portions that are separated by the circuit board or ribbon, at least one end portion being conductively attached to the circuit board or ribbon.

An array according to claim 10 wherein said end portions of the contact pins include respective first segments that engage the circuit board or ribbon, and respective second segments that are splayed away from each other and that each lie between the first segment and the tip of the respective pin.

An array according to claim 10 or 11 wherein said solid state light devices are light emitting diode devices.

Apparatus for bending a pair of contact pins of an electronic circuit device, eg a solid state light device, to facilitate mounting of the device, including:

separation structure locatable between the pins; and