Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/46—Manufacturing multilayer circuits
  • H05K3/4644—Manufacturing multilayer circuits by building the multilayer layer by layer, i.e. build-up multilayer circuits
  • H05K3/4664—Adding a circuit layer by thick film methods, e.g. printing techniques or by other techniques for making conductive patterns by using pastes, inks or powders
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
  • H05K3/4038—Through-connections; Vertical interconnect access [VIA] connections
  • H05K3/4053—Through-connections; Vertical interconnect access [VIA] connections by thick-film techniques
  • H05K3/4069—Through-connections; Vertical interconnect access [VIA] connections by thick-film techniques for via connections in organic insulating substrates
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/03—Use of materials for the substrate
  • H05K1/0393—Flexible materials
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
  • H05K1/092—Dispersed materials, e.g. conductive pastes or inks
  • H05K1/095—Dispersed materials, e.g. conductive pastes or inks for polymer thick films, i.e. having a permanent organic polymeric binder
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
  • H05K2201/09—Shape and layout
  • H05K2201/09818—Shape or layout details not covered by a single group of H05K2201/09009 - H05K2201/09809
  • H05K2201/09981—Metallised walls
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
  • H05K2203/06—Lamination
  • H05K2203/063—Lamination of preperforated insulating layer
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
  • H05K3/12—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using thick film techniques, e.g. printing techniques to apply the conductive material or similar techniques for applying conductive paste or ink patterns
  • H05K3/1216—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using thick film techniques, e.g. printing techniques to apply the conductive material or similar techniques for applying conductive paste or ink patterns by screen printing or stencil printing
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/46—Manufacturing multilayer circuits
  • H05K3/4685—Manufacturing of cross-over conductors

Definitions

• the invention relates to a printed electrical circuit of the type with at least two crossed or superimposed conductive networks, separated by a dielectric.
• Printed circuits comprising two crossed or superimposed ⁇ -conducting networks, which feel electrically isolated from each other at certain connection points. They consist, in principle, of depositing by screen printing on the support a first layer of conductive ink to form a first network, of polymerizing this layer to dry and harden it, then of depositing by screen printing on certain parts of the first network a layer of insulating or dielectric ink and to polymerize it to harden and dry it, then to deposit by screen printing a second layer of conductive ink on the support and on certain parts of the first network and of the layer of dielectric ink, and to polymerize by heating this second layer of conductive ink.
• a second conductive network is thus obtained isolated from the first in certain areas by the intermediate layer of dielectric ink and connected to the first network by the areas where the second layer of conductive ink has been deposited directly on the first layer of conductive ink. It has been found that the circuits thus obtained have extremely significant drawbacks:
• conductive anchor layers migrate through the dielectric ink layer and establish short circuits between the two conductive networks;
• the dielectric ink layer becomes brittle by polymerization and breaks by bending or by significant bending, which leads to the rupture of the conductive tracks underlying the first network;
• the insulating inks exhibit a significant shrinkage on heating, which causes the upper conductive tracks to be cut off;
• the heating of the insulating ink for its polymerization is often accompanied by the formation of bubbles which make it impossible to deposit the second layer of conductive ink;
• the insulating inks adhere poorly to certain supports such as for example a polyester sheet; -
• the thickness of the insulating ink layer must be much greater than that of a conductive ink layer, hence the formation by the insulating ink of projections or protrusions on the support, and the first conductive network .
• the conductive tracks of the second network, deposited on these projections or projections, have cracks and / or micro-cracks and do not resist folding;
• the thickness of the insulating ink layer decreases during the polymerization heating and, in areas where it is not very large, reveals micro-points of the first layer of conductive ink, hence short circuits between the two conductive networks;
• It relates to a circuit, printed with at least two crossed or superimposed conductive networks formed by deposition by screen printing of conductive ink (s), this circuit being free of the aforementioned defects and able to be produced at cost price. which is three or four times lower than that of an equivalent circuit obtained by known screen printing methods.
• a printed circuit comprising a dielectric support and at least two electrically conductive networks carried by the support, these networks being crossed or superimposed and electrically isolated from each other with the exception of certain points of interconnection, characterized in that said networks each comprise tracks of polymerized conductive ink which are formed respectively on either side of the support so as to be electrically isolated from each other by said support, the connections between the networks being established through the support by conductive ink films.
• the two conductive networks of the printed circuit are perfectly separated from one another by the support of the circuit, which is of constant thickness, which has a flat surface and that the conductive particles of the inks do not can cross through migration.
• connections between the networks are holes passing through the support and the walls of which are at least partially covered with a uniform layer of conductive ink.
• the desired connections between the two conductive networks are thus very easily obtained by means of holes passing through the support and with walls covered at least partially with a film of conductive ink, which establish homogeneous connections between the networks. and reliable.
• This characteristic of the invention differs completely from what is known from this prior art relating to conventional printed circuits with copper tracks on both sides of a rigid and thick support made of epoxy glass.
• the two networks are interconnected by "metallized" holes in the support. These holes are drilled in the support in the desired places, after complete manufacture of the two conductive networks of the circuit, then their internal cylindrical wall is coated with a conductive metal film by electroplating, which is a long and expensive process, which further increases the cost price of such a printed circuit.
• the connections between the two networks are formed at the same time as the conductive networks, in a single operation and without repeating the circuit for further processing.
• the invention also relates to a multilayer printed circuit, comprising several crossed or superimposed conductive networks, electrically isolated from each other with the exception of certain interconnection points between certain zones of at least some of said networks, which is characterized in that '' it comprises a printed circuit, the support of which is provided on both sides with a conductive network formed by screen printing of conductive ink (s), and in that at least one face of this printed circuit is coated a sheet or film of dielectric material having an outer face which comprises a conductive network formed by screen printing deposit of conductive ink (s), and connection holes formed through said sheet or said film and of which the walls are at least partially covered with conductive ink.
• this multi-layer printed circuit comprises a stack of said sheets or films of dielectric material, each of which comprises on one face a conductive network of the type above and connecting holes with walls at least partially covered with conductive ink.
• Such a multi-layer printed circuit can have a thickness of between 1 and 2 mm for example, it can be perfectly flexible and include a large number of crossed or superimposed conductive networks, this number being for example between 3 and 15.
• the invention also provides a method of manufacturing a printed circuit, characterized in that it consists in forming holes in a flat support of dielectric material at predetermined points, to be deposited by screen printing conductive ink on said support. by forming on each of its faces a conductive network and at least partially coating the walls of said holes with conductive ink, and then polymerizing the ink by heating.
• the method consists in depositing by screen printing the conductive ink simultaneously on the two faces of the support, or else in depositing by screen printing a first network of conductive ink on a first face of the support, polymerize the ink by heating, then deposit by screen printing on the second face of the support a second network of conductive ink and polymerize by heating.
• the method then consists in fixing on a face of the circuit previously obtained a sheet or a film of dielectric material pierced with holes at predetermined points, so that these holes open onto conductive parts of said circuit, to deposit by screen printing on the outer face of said sheet or film a layer of conductive ink, so as to form on this face a conductive network and at least partially cover the walls of said holes of conductive ink, and to polymerize by heating the ink thus deposited.
• FIG. 1 is an enlarged perspective view of part of a printed circuit according to the prior art
• - Figure 2 is a sectional view of part of this circuit;
• - Figure 2A is an enlarged view of the detail circled in II - A in Figure 2;
• - Figure 3 is an enlarged schematic view, in perspective, of part of a printed circuit according to the invention;
• FIG. 4 is a sectional view of part of the circuit of Figure 3;
• FIG. 5 shows schematically, under. block form, the steps of a method of manufacturing a printed circuit according to the invention;
• - Figure 6 shows schematically, in the form of blocks, the additional steps of manufacturing a multi-layer printed circuit
• - Figure 7 is a sectional view of a multi-layer printed circuit according to the invention.
• This printed circuit 10 comprises a flat support 11 of dielectric material which may be rigid and thick, but which is advantageously thin and flexible, such as a polyester film with a thickness of approximately 0.1 mm for example.
• a polyester film with a thickness of approximately 0.1 mm for example.
• first conductive tracks 13, 14 and 15 by deposition by screen printing of a conductive ink which is in subsequently polymerized by heating.
• This insulating layer 16 has a greater thickness than that of the conductive tracks 13, 14 and 15.
• New conductive tracks 17 are then formed as previously on the face 12 of the support 11, on the layer 16 of insulating ink and also on certain parts of the. first conductive tracks 13, 14 or 15 at the places where it is desired to obtain electrical connections between the first conductive network formed by tracks 13, 14 and 15 and the second conductive network formed by conductive tracks 17.
• the conductive tracks have a width of approximately 1 mm, a thickness of between 20 and 30 microns and that the strips 16 of insulating ink have a thickness and a width which are several times greater than those of the conductive tracks.
• Figure 2 is a sectional view of the printed circuit 10 in the area where a conductive track 17 of the second network intersects a conductive track 15 of the first network being isolated therefrom by the strip 16 of dielectric ink.
• the edges of this strip 16 form, on the upper surface 12 of the support 11, projections or projections 18, and the thickness of the conductive track. 17 deposited on these projections is much weaker than at the places where it is deposited on a flat part, due to the fluidity of the conductive ink.
• the manufacturing process for such a printed circuit 10 is relatively long and requires four screen printing screens used respectively to deposit the conductive tracks 13, 14 and 15 of the first conductive network, to deposit the strips 16 of insulating ink, to deposit the conductive tracks 17 of the second conductive network, and for depositing a new layer of insulating ink 16 on certain parts of the tracks of the second network and of the first insulating layers.
• a new ink layer can only be deposited after polymerization of the previously deposited ink layer, which leads to a succession of screen printing and heating operations for polymerization.
• the essential object of the invention is to avoid all of these drawbacks and in addition to very significantly improve the quality of the printed circuits.
• FIGS. 3 and 4 show a printed circuit according to the invention.
• This printed circuit 30 comprises a flat support 31 of dielectric material, such as a polyester film with a thickness of between 15 and 1500 microns, for example between 80 and 100 microns.
• dielectric material such as a polyester film with a thickness of between 15 and 1500 microns, for example between 80 and 100 microns.
• MYLAR polyester film with a thickness of between 15 and 1500 microns, for example between 80 and 100 microns.
• 32 and 33 of the support 31 each comprise a conductive network formed by deposition by screen printing of conductive ink 10
• the conductive network formed on the upper face 32 of the support 31 comprises conductive tracks 34, 35, 36, 37, 38 ets.and contact pads 39 and 40 connected to tracks 37 e- 38 respectively.
• the conductive network formed on the underside 33 of the support 31 comprises conductive tracks 41, only one of which has been shown in FIG. 3.
• the desired connections between the two conductive networks are established by means of holes 42 in the support 31, which lead to their upper end on a conductive track of the first network and at their lower end on a conductive track of the second network.
• a hole 42 can be, for example, at least partially filled, with polymerized conductive ink. In the example shown in Figure 3, one end of track 41 of.
• a lower conductive network is connected by such a connection to track 35 of the upper conductive network, and the other end of track 41 is connected to track 38 of the upper conductive network by a film 43 of conductive ink at least partially coating the wall of the hole 42 and ending at each end of the hole with an annular area 44 on the corresponding face of the support 31, this area having an outside diameter greater than the diameter of the hole 42.
• An important characteristic of the invention is that the thickness of the film 43 of conductive ink coating the wall with a hole is equal to the thickness of the track 41 or 38 of conductive ink formed on the face 33 or 32 of the support.
• This quality of the connection through the support is due to the method according to the invention which consists in making the tracks and the connections through the support in a single surgery.
• the holes are filled with conductive ink, they contain a relatively large quantity of ink capable of producing shrinkage upon polymerization, hence the risk of cracks on the edges of the holes.
• the holes 42 can be of circular section as shown, in which case their cylindrical wall is completely covered with a conductive ink film, or else of square or rectangular section, in which case only one flat face of the hole is coated with ink or two opposite sides.
• a connection between two conductive tracks each formed on a different face of the support can also be made on the edge of the support, as indicated in 43a in FIG. 3.
• a tab projecting from the support such as that of FIG. 3 carrying the ends of the tracks 34, 35, 36, 37, can be used as the male part of a standard connector.
• this tab can be folded around a corresponding tab of a rigid support having the desired thickness.
• the pads or contact pads 39, 40, as well as the ends of the tracks 34 - 37 which end at the edge 43 of the support 41 and which serve as connecting tracks with a connector can be formed by ink.
• conductive different from the ink used for the conductive tracks and which exhibits, after polymerization, a hardness or a mechanical resistance greater than that of the conductive tracks.
• the pads or contact pads can be formed with the ink supplied by the company EPOTECNY under the reference H 20 F - 1, and that the conductive tracks can be formed with the ink. supplied by COMPTOIR LYON ALEMAND LOUYOT under the reference VF 5, or by the company DUPONT DE NEMOURS under reference 40 49.
• resistive, capacitive or inductive screen inks commercially available, to form a conductive network by serigraphy. printed with resistors, capacitors or inductors, respectively.
• solder components such as resistors,: capacitors, inductors, transistors, integrated circuits, etc.
• the flexible support 31 consisting of a polyester film for example, can be replaced by a thicker sheet of dielectric material, such as a sheet of epoxy glass for example.
• a rigid or semi-rigid printed circuit is thus obtained depending on the thickness of the support.
• the diameter of the connection holes 42 between the two conductive networks of the circuit must be determined so that the walls of the holes are partially or completely covered with conductive ink when the conductive networks are formed on the support by deposition by conductive ink screen printing. This diameter is a function of the viscosity of the ink used and the thickness of the support. It has been found that, for the most part from conductive inks, and when the support has a thickness of approximately 80 to 100 microns, the best results are obtained with holes with a diameter of approximately 0.8 mm at least.
• the first step 45 consists in drilling the support 31 so as to form holes therein of a predetermined size at the places where it is desired to provide connections between the two conductive networks.
• the next step vante 46 consists in depositing on each face 32, 33 of the support 31 a network of conductive ink, by means of
• the walls of the holes 42 drilled in the support are coated, at least partially, with a film of conductive ink at the same time as the conductive networks are formed on the two faces of the support 31.
• the next step 47 consists in subjecting the support, the two faces of which comprise a network of conductive ink, to a heater for polymerizing the ink. This heating is generally carried out in an oven, for example with infrared or ultraviolet radiation, at a temperature of 150 ° C. for a period of 5 to 10 minutes.
• the printed circuit is then finished and can be used.
• one and / or the other of the conductive networks can be covered with a film of dielectric material such as an insulating varnish, in a conventional manner.
• a network of conductive ink is deposited by screen printing on a single face of the support 31, then the circuit is subjected to heating to polymerize the ink, in the same way as previously Then, as indicated by the arrow in dotted lines 48, an deposits on the other face of the support another network of conductive ink which is then subjected, as indicated by the arrow in dotted lines 49 , to a new heating to polymerize this ink.
• the contact pads or pads 39, 40 can be formed at the same time as the conductive tracks of the corresponding conductive network, that is to say with the same conductive ink, or they can be formed separately by an additional deposit by screen printing of a conductive ink which, after polymerization, exhibits greater hardness or greater resistance this mechanical, as the inks of the conductive tracks.
• a flexible, semi-rigid or rigid support is used, the two faces of which already have a conductive network, for example made of copper.
• a conductive network for example made of copper.
• This technique can also be used to form pads or contact pads on conductive copper networks. This can be done by using a conductive ink containing particles. silver which, after polymerization of the ink, will form contact areas on the copper tracks or connected to the copper tracks.
• FIG. 6 schematically represents another variant of the method according to the invention, for the manufacture of a multi-layer printed circuit represented in FIG. 7.
• This circuit 50 is produced for example from a printed circuit 51 obtained by the method of FIG. 5.
• the circuit 51 therefore comprises a support 52, such as a polyester film with a thickness of 80 to 100 microns, the two faces of which each comprise a conductive network comprising conductive tracks 53 and 54 respectively and connections between the two networks formed by holes 55 passing through the support 52 and with walls coated, at least partially, with polymerized conductive ink.
• a support 56 such as a sheet or a polyester film, having a thickness between 15 and 100 microns and which is for example less than the thickness of the support 52 of the circuit 51.
• a conductive network comprising conductive tracks 57. Holes 58 formed through the. sheet 56 and provided with a film of polymerized ink, provide the desired connections between the conductive tracks 57 formed on the upper face of the film 56 and the conductive tracks 53 of the network formed on the upper face of the printed circuit 51.
• Holes 62 formed through the film 60 and provided with a film of polymerized conductive ink provide the desired connections between the conductive tracks 61 and the conductive tracks 57.
• a hole 62 of the film 60 can be vertically aligned with a hole 58 of the sheet 56, and in this case a connection is established between the tracks 61, 57 and 53.
• the method of manufacturing such a multi-layer printed circuit for example from a printed circuit 51 obtained by the method of FIG. 5, consists, as shown in FIG. 6, in a first step 65 of drilling the sheet or film 56 of dielectric material.
• the next step 66 consists in fixing this sheet of this film on one face of the printed circuit 51, for example by gluing or hot pressing.
• the next step 67 consists of forming, by deposition by screen printing of conductive ink, a conductive network 57 on the upper or free face of the sheet or film 56.
• the next step 68 is a heating operation to polymerize the deposited conductive ink. These operations are then repeated for the fault or the film 60.
• the cost of a printed circuit according to the invention is approximately 80 times lower than that of a conventional printed circuit with conductive copper tracks on an epoxy glass support, and three to four times lower than that of a circuit such as that of FIGS. 1 and 2.
• the rate of waste in the manufacture of printed circuits according to the invention is zero, due to the possibility of retouching the conductive networks formed by deposition by screen printing of conductive ink then polymerized, while the rate of waste in the manufacture of circuits printed such as those of Figures 1 and 2 is of the order of 25 to 30% minimum.
• the circuit is passed only once in an oven, for the polymerization of the ink, while the number of passages in an oven is three or four in the prior art.
• the reliability of a printed circuit according to the invention is much higher than that of a printed circuit of the type represented in FIGS. 1 and 2, because the tracks of conductive ink and the connections do not break, even at following a marked folding of support.
• the deposit simultaneous conductive inks on both sides of the support, or the two successive deposits of conductive ink first on one face, then on the other of the support, ensure: in all cases a good coating of the walls of the connection holes by a uniform layer of a single ink which is then polymerized by heating, which has the effect of achieving a homogeneous connection and devoid of internal mechanical tension (which avoids the expansion gradients, the appearance of microcracks, etc.).
• the thickness of the conductive ink film coating the walls of the connection holes is substantially equal to that of the conductive tracks formed on the two faces of the support, which avoids the risks of cracks due to cracks at the edges of the holes after polymerization.
• the invention makes it possible to produce printed circuits with at least two crossed or superimposed conductive networks, which are flexible, semi-rigid or rigid, depending on the nature and thickness of the dielectric material support.
• the invention also makes it possible to produce printed circuits from polyester sheets, the two faces of which are metallized, for example by a copper film, which are treated by photoengraving to form conductive networks on the two faces, and in which the connections between the two networks are established by means of holes passing through the support and the walls of which are coated, at least partially, with polymerized conductive ink.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Production Of Multi-Layered Print Wiring Board (AREA)
• Manufacturing Of Printed Wiring (AREA)
• Printing Elements For Providing Electric Connections Between Printed Circuits (AREA)
• Non-Metallic Protective Coatings For Printed Circuits (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9245779

Family Applications (1)

Country Status (11)

Cited By (5)

Families Citing this family (3)

Citations (5)

• 1980
  • 1980-09-09 FR FR8019462A patent/FR2490059A1/fr active Granted
• 1981
  • 1981-08-28 AU AU75379/81A patent/AU7537981A/en not_active Abandoned
  • 1981-08-28 EP EP81902466A patent/EP0059206B1/fr not_active Expired
  • 1981-08-28 WO PCT/FR1981/000109 patent/WO1982000938A1/fr not_active Ceased
  • 1981-08-28 JP JP56502909A patent/JPS57501353A/ja active Pending
  • 1981-09-08 BE BE0/205905A patent/BE890272A/fr not_active IP Right Cessation
  • 1981-09-08 ES ES505299A patent/ES505299A0/es active Granted
  • 1981-09-09 CA CA000385491A patent/CA1171549A/en not_active Expired
  • 1981-09-09 IT IT8123851A patent/IT1138586B/it active
• 1982
  • 1982-05-05 NO NO821481A patent/NO821481L/no unknown
  • 1982-05-06 DK DK204982A patent/DK204982A/da not_active Application Discontinuation

Patent Citations (5)

Also Published As

Similar Documents

Legal Events