Patent EP0588040A2 successfully refreshed from Google Patents.
EP0588040A2
Expired / Lapsed
EP
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Light source and technique for mounting light emitting diodes
Assignee: Agilent Technologies Inc
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Filing: 1993-08-02
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Granted: —
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Expires: 2013-08-02
Abstract
Abstract A light emitting diode has both end faces metallized and is mounted on a substrate with the light emitting junction perpendicular to the substrate. The electrically conductive ends are electrically bonded to conductive areas on the substrate by solder or conductive adhesive. LED dice can be placed on the substrate by temporarily attaching the dice to a tape which has been wrapped around a knife edge. The dice tilt as the tape wraps around the edge and are picked off one at a time by a vacuum collet while temporarily supported by a movable finger, and then transferred by the vacuum collet to a substrate. A similar method may be used for placing semiconductor dice on a substrate without the tilting of dice around the edge. In another embodiment, an array of LEDs can be assembled in windows through a metallized plastic tape which is bonded to a foundation with additional metallized leads.
Inventors
- 👤 Shane Harrah
- 👤 Trevor J. Smith
- 👤 John Uebbing
- 👤 Thomas Fajardo
- 👤 Jerry D. Kreger
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 19:46
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/83; H10H20/831; H10H20/8314; H10H20/01; H10H20/832; H10H20/84; H10H20/841; H10H20/85; H10H20/8506; H10H29/00; H10H29/10; H10H29/14; H10H29/142; H10W; H10W90/00; Y; Y10; Y10T; Y10T156/00; Y10T156/17; Y10T156/1702; Y10T156/1744; Y10T156/1768; Y10T29/00; Y10T29/53; Y10T29/5313; Y10T29/53191; Y10T29/53261
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
135 words
A light source comprising: a substrate (17); a light emitting diode (10) having a light emitting junction (113;213;313) perpendicular to the substrate (17) and having an electrically conductive layer (114,151;214,251;314) at each end of the light emitting diode (10) perpendicular to the substrate (17), each of said electrically conductive layers (114,151;214,251;314) comprising at least one metal layer, at least one of the metal layers (151; 251) on an end of the light emitting diode (10) covering less than the entire end of the light emitting diode (10) for emission of light through the end face; and means (25) for mounting the light emitting diode (10) on the substrate (17) with the junction (113;213;313) perpendicular to the substrate (17) and the electrically conductive layers (114,151;214,251;314) in electrical contact with conductive areas (19,21,22) on the substrate (17).
Claim 2
Dependent Claim
121 words
A light source as recited in claim 1 wherein the light emitting diode (10) comprises: a layer (111;211;311) of p-type material; and a layer (112;212;312) of n-type material adjacent to the p-type material for forming a light emmitting junction (113; 213;313) between the p- and n-type materials; and wherein the electrically conductive layers (114,151;214,251;314) comprise: a layer (114;214;314) of metal on the opposite face of the n-type material from the junction (113;213;313); and a layer (151;251) of metal on the opposite face of the p-type material from the junction (113;213;313); and wherein the means (25) for mounting comprises an electrically conductive material (16) adhering to each metal layer (114, 151;214,251;314) and to an adjacent conductive area (19) on the substrate (17).
Claim 3
Dependent Claim
42 words
A light source as recited in claim 1 wherein such a metal layer comprises a metal pad (151) on the end of the light emitting diode (10) and having an edge adjacent to a side face of the light emitting diode (10).
Claim 4
Dependent Claim
33 words
A light source as recited in claim 3 wherein the metal pad (251) comprises a stripe extending between opposite side faces of the light emitting diode (10) and perpendicular to the substrate (17).
Claim 5
Dependent Claim
67 words
A light source as recited in claim 1 wherein the substrate (17) comprises a plurality of conductive areas (19,21,22) for electrical connection between the light emitting diode (10) and an external circuit, an insulating layer (23) over at least a portion of the conductive areas (19), and a hole through the insulating layer (23) adjacent to each end of the light emitting diode (10) for electrical contact.
Claim 6
Dependent Claim
37 words
A light source as recited in claim 5 wherein the hole is sufficiently large for receiving the entire light emitting diode (10) and a center portion of the light emitting diode (10) spans between conductive areas (19).
Claim 7
Dependent Claim
39 words
A light source as recited in claim 5 wherein a center portion of the light emitting diode (10) overlies a portion of the insulating layer (23) and each conductive layer (114,151;214,251;314) overlies a hole through the insulating layer (23).
Claim 8
Dependent Claim
39 words
A light source as recited in claim 1 wherein the width of the light emitting diode (10) parallel to the junction (113; 213;313) is less than the height of the light emitting diode (10) perpendicular to the junction (113;213;313).
Claim 9
Dependent Claim
51 words
A light source as recited in claim 1 further comprising a non-conductive layer for reflection between an end of the light emmitting diode (10) and a metal layer and at least one hole (354) through the non-conductive layer for electrical contact between the metal layer and the light emitting diode (10).
Claim 10
Dependent Claim
180 words
A light source comprising: a substrate (17); and a light emitting diode (10) mounted on the substrate (17), the light emitting diode (10) comprising: a layer (111;211;311) of p-type material; a layer (112;212;312) of n-type material adjacent to the p-type material forming a light emitting junction (113;213;313) between the p- and n-type materials; a layer (114;214;314) of conductive material on the opposite face of the n-type material from the junction (113;213;313); and a layer (151;251) of conductive material on the opposite face of the p-type material from the junction (113;213;313); and means for mounting (25) the light emitting diode (10) on the substrate (17) with the junction (113;213;313) perpendicular to the substrate (17) and the electrically conductive layers (114,151;214,251;314) in electrical contact with conductive areas (19,21,22) on the substrate (17), each of said electrically conductive layers (114,151;214,251;314) comprising at least one metal layer, at least one of the metal layers (114,151;214,251;314) on an end of the light emitting diode (10) covering less than the entire end of the light emitting diode (10) for emission of light through the end face.
Claim 11
Dependent Claim
47 words
A light source as recited in claim 10 wherein such a metal layer comprises a metal pad (151) on the end of the light emitting diode (10) and having an edge adjacent to a side face of the light emitting diode (10) adjacent to the substrate (17).
Claim 12
Dependent Claim
33 words
A light source as recited in claim 11 wherein the metal pad (251) comprises a stripe extending between opposite side faces of the light emitting diode (10) and perpendicular to the substrate (17).
Claim 13
Dependent Claim
85 words
A light source comprising: a layer (11) of p-type material; a layer (12) of n-type material adjacent to the p-type material forming a light emitting junction (13) between the p- and n-type materials; a layer (14) of metal on the n-type material on the opposite face from the junction (13); a layer (14) of metal on the p-type material on the opposite face from the junction (13); and a layer (16) of heat flowable conductive material on the outside face of each metal layer (14).
Claim 14
Dependent Claim
20 words
A light source as recited in claim 13 wherein the layer (16) of heat flowable conductive material comprises a solder.
Claim 15
Independent Claim
75 words
A method for mounting light emitting diode dice (10,29) on a substrate (17) comprising the steps of: temporarily attaching the dice (10,29) to an adhesive on a flexible tape (26) in a column extending along the tape (26); bending the tape (26) for successively tilting each die (29) relative to a successive die (10) in the column; removing a tilted die (29) from the adhesive; and advancing the removed die (29) toward the substrate (17).
Claim 16
Dependent Claim
27 words
A method as recited in claim 15 comprising engaging at least one side face of the tilted die (29) for removing the die (29) from the adhesive.
Claim 17
Dependent Claim
25 words
A method as recited in claim 16 comprising engaging opposite side faces of the tilted die (29) for removing the die (29) from the adhesive.
Claim 18
Dependent Claim
40 words
A method as recited in claim 15 comprising the preliminary step of transferring a plurality of dice (10) from a first stretchable tape to a second non-stretchable tape (26), and wherein the bending step comprise bending the second tape (26).
Claim 19
Independent Claim
106 words
A method for mounting light emitting diode dice (10,29) on a substrate (17) comprising the steps of: temporarily attaching the dice (10,29) to adhesive on a flexible tape (26) in a column extending along the tape (26); passing the tape (26) around an edge (28) which bends the tape (26) and successively tilts each die (29) relative to a successive die (10) in the column; engaging a side face of a tilted die (29) with a vacuum collet (31) for supporting the die (29) and removing it from the adhesive; and advancing the die (29) toward the substrate (17) by means of the vacuum collet (31).
Claim 20
Dependent Claim
45 words
A method as recited in claim 19 further comprising the steps of temporarily supporting the tilted die (29) from the opposite face while being engaged by the vacuum collet (31), and removing the temporary support (33) before advancing the die (29) to the substrate (17).
Claim 21
Dependent Claim
59 words
A method as recited in claim 20 comprising the steps of sensing the position of each die (29) in the space between the vacuum collet (31) and the temporary support (33), and moving the tape (26) forward or backwards as required for positioning the die (29) in a selected location between the vacuum collet (31) and temporary support (33).
Claim 22
Dependent Claim
34 words
A method as recited in claim 19 wherein the passing step comprises wrapping the tape (26) around an edge (28) for bending the tape (26) through an angle of at least 150 o .
Claim 23
Dependent Claim
64 words
A method as recited in claim 19 further comprising the steps of: mounting a semiconductor wafer on a stretchable adhesive substrate; sawing the wafer for separating individual light emitting diode dice (10); stretching the adhesive substrate for separating the dice (10) from each other; transferring the dice to adhesive on a non-stretchable tape (26); and using the non-stretchable tape (26) in the passing step.
Claim 24
Dependent Claim
63 words
A method as recited in claim 19 wherein the dice (10,29) are arrayed on the tape (26) in a plurality of columns perpendicular to the edge and rows parallel to the edge, and comprising the step of moving the tape (26) and edge transverse to the vacuum collet (31) for placing individual dice in a row in front of the vacuum collet (31).
Claim 25
Dependent Claim
33 words
A method as recited in claim 24 comprising the step of advancing the tape (26) to a new row of dice after each row of dice has been placed on the substrate (17).
Claim 26
Independent Claim
108 words
A method for mounting semiconductor dice (64) on a substrate (63) comprising the steps of: temporarily attaching the dice (64) to adhesive on a flexible tape (61) in a column extending along the tape (61); bending the tape (61) around an edge (62) adjacent to a location on a substrate (63) where a die (64) is to be placed, for successively bringing each die (64) to the bent edge of the tape (61); removing a die (64) from the adhesive adjacent to the bent edge of the tape (61); and advancing the removed die (64) beyond the bent edge of the tape (61) and toward the substrate (63).
Claim 27
Dependent Claim
37 words
A method as recited in claim 26 comprising engaging a face of the die (64) with a vacuum collet (67) for removing the die (64) from the adhesive and advancing the die (64) toward the substrate (63).
Claim 28
Dependent Claim
30 words
A method as recited in claim 27 comprising engaging the opposite side face of the die (64) with a temporay support (68) for removing the die (64) from the adhesive.
Claim 29
Dependent Claim
34 words
A method as recited in claim 26 wherein the passing step comprises wrapping the tape (61) around an edge (62) for bending the tape (61) through an angle of at least 150 o .
Claim 30
Dependent Claim
33 words
A method as recited in claim 26 comprising placing the die (64) on the substrate (63) with the face of the die (64) previously adhered to the adhesive being on the substrate (63).
Claim 31
Dependent Claim
51 words
A method as recited in claim 26 wherein each die (64) comprises a light emitting diode having a light emitting junction (66) parallel to the adhesive on the tape (61), and comprising placing the die (64) on the substrate (63) with the light emitting junction (66) parallel to the substrate (63).
Claim 32
Dependent Claim
76 words
A method as recited in claim 26 wherein each die (64) comprises a light emitting diode having a light emitting junction (66) parallel to the adhesive on the tape (61), and comprising: removing the die (64) from the adhesive after the die (64) has moved past the edge (62) and tilted relative to the substrate (63), and placing the die (64) on the substrate (63) with the light emitting junction (66) perpendicular to the substrate (63).
Claim 33
Dependent Claim
64 words
A method as recited in claim 26 wherein the dice (64) are arrayed on the tape (61) in a plurality of columns perpendicular to the edge and rows parallel to the edge, and comprising the step of moving the tape (61) and edge transverse to the vacuum collet (67) for placing individual dice (64) in a row in front of the vacuum collet (67).
Claim 34
Dependent Claim
76 words
A method as recited in claim 26 comprising the steps of: advancing the tape (61) so that the face of a die (64) adjacent to the adhesive engages a temporary support (68) beyond the edge (62); engaging the opposite face of the die (64) with a vacuum collet (67) for removing the die (64) from the tape; retracting the temporary support (68); and advancing the die (64) toward the substrate (63) with the vacuum collet (67).
References Cited (Backward Citations)
No citation records indexed.
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