Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/66—Circuits
  • H05B6/666—Safety circuits
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F27/00—Details of transformers or inductances, in general
  • H01F27/06—Mounting, supporting or suspending transformers, reactors or choke coils not being of the signal type
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F27/00—Details of transformers or inductances, in general
  • H01F27/40—Structural association with built-in electric component, e.g. fuse
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F5/00—Coils
  • H01F5/02—Coils wound on non-magnetic supports, e.g. formers
• • 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
  • H05K1/18—Printed circuits structurally associated with non-printed electric components
• • 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
  • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
  • H05K3/301—Assembling printed circuits with electric components, e.g. with resistor by means of a mounting structure
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F27/00—Details of transformers or inductances, in general
  • H01F27/06—Mounting, supporting or suspending transformers, reactors or choke coils not being of the signal type
  • H01F2027/065—Mounting on printed circuit boards
• • 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
  • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
  • H05K2201/10007—Types of components
  • H05K2201/1003—Non-printed inductor
• • 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
  • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
  • H05K2201/10227—Other objects, e.g. metallic pieces
  • H05K2201/10424—Frame holders
• • 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
  • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
  • H05K2201/10431—Details of mounted components
  • H05K2201/10507—Involving several components
  • H05K2201/10515—Stacked components
• • 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
  • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
  • H05K2201/10613—Details of electrical connections of non-printed components, e.g. special leads
  • H05K2201/10621—Components characterised by their electrical contacts
  • H05K2201/10651—Component having two leads, e.g. resistor, capacitor
• • 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
  • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
  • H05K2201/10613—Details of electrical connections of non-printed components, e.g. special leads
  • H05K2201/10742—Details of leads
  • H05K2201/1075—Shape details
  • H05K2201/10757—Bent leads
• • 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
  • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
  • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
  • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
  • H05K3/3447—Lead-in-hole components

Definitions

• the present invention relates to a high-frequency heating device, especially, a high-frequency heating device having a printed circuit board on which a transformer unit is mounted, wherein said printed circuit board is used in inverter-type high-frequency heating devices or the like.
• An inverter-type high-frequency heating device as shown in FIG. 5, contains a transformer unit 73 in which a transformer 72 is mounted on a printed circuit board 71.
• the circuit of the transformer unit will be explained hereinbelow with reference to FIG. 6.
• the output of a commercial power source 74 is transmission-wave rectified with a rectification circuit 75 such as a diode bridge or the like, converted into a high- frequency voltage by an inverter 76, and applied to a primary winding 77 of the transformer 72.
• a high- frequency high voltage of several kV is generated in a secondary winding 78 of the transformer 72.
• This high- frequency high voltage is rectified by a voltage-double rectification circuit 81 composed of a capacitor 79 and a diode 80.
• a high voltage is applied to a magnetron 82 which is a microwave generator.
• a heater winding 83 of the transformer 72 is connected to a filament 84 of the magnetron 82 for heating the filament 84.
• the magnetron 82 generates microwaves under the effect of heating of the filament 84 and high voltage application.
• the transformer with the configuration shown in FIG. 7 is well known (for example, Patent Reference 1: JP-A-2001- 189221) . Referring to FIG.
• the transformer 72 used in the aforementioned transformer unit 73 comprises a bobbin 85 having a primary winding 77, a secondary winding 78, and a heater winding 83 concentrically wound thereon, and has a structure in which cores 86 are inserted from both sides into the center of the bobbin 85.
• this transformer 72 as shown in FIG. 8, comprises in the bottom portion thereof a primary winding connection pin 87, a secondary winding connection pin 88, a heater winding connection pin 89, and a ground connection pin 90. Those pins are inserted in the through holes of a printed circuit board 71 prior to mounting and connected to the circuit pattern of the printed circuit board 71 by soldering.
• high-frequency heating devices are required to be compact and highly functional, the size of components thereof has been decreased and components with a higher additional value have been used.
• high-voltage components such as the capacitor 79 or diode 80 constituting the voltage-double rectification circuit 81 are much larger than the components constituting the control circuit, and a region for high- voltage components on the printed circuit board 71 was increased in size to ensure the required space for mounting those high-voltage components.
• the spacing of the circuit pattern had to be enlarged to ensure the required insulating distance from the high-voltage components.
• the high-voltage component region in the printed circuit board had to be enlarged.
• FIGs. 9A and 9B show a cross-sectional view and a side view of a transformer according to the prior invention.
• FIG. 10 is a perspective view of the transformer
• FIG. 11 is a perspective view of the transformer unit.
• a transformer 11 mounted on the transformer unit of the prior invention which served as a premise for the present invention is composed of a resin bobbin 13, a primary winding 15, a secondary winding 17, and a heater winding 19 wound around the bobbin 13, and a core 21.
• the core 21 is composed of a I-shaped core 21a with a rectangular cross section which is inserted in the center of the bobbin 13 and a U-shaped core 21b of a U-like shape in the side view thereof which is connected to both ends of the I-shaped core 21a.
• the transformer 11 is mounted on the printed circuit board 23 so that the U-shaped core 21b faces down.
• the bobbin 13 comprises a plurality (a total of four in the related art) component holding portions composed of respective pairs of clamping pieces 25, 27.
• a capacitor 31 which is a high- voltage component constituting the voltage-double rectification circuit 81 is sandwiched by a pair of clamping pieces 27, and the diode 33 is sandwiched by a pair of clamping pieces 25.
• the component holding portions of the present embodiment are formed by providing the respective pairs of clamping pieces 25, 27 in a vertical condition at the side surface of the bobbin 13, with a spacing therebetween being about the thickness of the high-voltage components.
• the component holding portions are not limited to the clamping pieces 25, 27 and may have any structure, provided that they can hold the high-voltage components.
• connection terminals of the secondary winding 17 or heater winding 19 are mutually connected to those lead wires based on respective circuits. Therefore, in the outer peripheral region, except the mounting side on the printed circuit board 33 of the transformer 11, the connection cords from the magnetron or the like are connected directly, rather than via the printed circuit board 23.
• the component holding portions for holding the high-voltage components such as the capacitor 31 and diode 33 are provided at the side surface of the bobbin 13.
• connection terminals of the secondary winding 17 and heater winding 19 are connected to the outer peripheral region, except the side where the transformer 11 is mounted on the printed circuit board 23, the connection cord from the magnetron or the like can be directly connected to the transformer 11, rather than via the printed circuit board 23.
• the circuit pattern in the printed circuit board 23 can be decreased in size.
• the circuit pattern in the printed circuit board 23 can be further reduced in size or simplified.
• the holding place for the high-voltage component is not limited to the side surface of the bobbin 13 and can be any location, provided it is in the outer peripheral region of the transformer 11.
• the primary winding connection pin 87, secondary winding connection pin 88, heater winding connection pin 89, and ground connection pin 90 have been conventionally provided at the bottom of the transformer 72, as shown in FIG. 8, the pins were inserted into the through holes of the printed circuit board 71 prior to mounting, and connected to the circuit pattern of the printed circuit board 71 by soldering.
• FIGs. 2A and 2B are schematic drawings illustrating the attachment of the transformer unit to the printed circuit board by using the lead terminals of the components
• FIG. 2A is the perspective view thereof
• FIG. 2B is an enlarged cross-sectional view of the zone in the vicinity of a slit portion.
• FIGs. 3A and 3B are perspective views illustrating a drop test of the printed circuit board.
• the ⁇ reference numeral 1 stands for a printed circuit board carrying a transformer unit of the prior invention, 2 - a bobbin of a transformer unit comprising the transformer shown in FIG. 11, the bobbin being schematically shown as a rectangular parallelepiped.
• Locking protrusions 2a for locking the component lead terminals are formed in a plurality of locations in the lower part of the side surface of the bobbin 2, and the below-described longitudinal slits 2b are formed in the locking protrusions 2a.
• the reference numeral 3 stands for an electric component (diode, capacitor, or the like) held in the outer peripheral region of the bobbin and/or transformer.
• the reference numeral 3a stands for a lead terminal of the component 3.
• the component lead terminals 3a are inserted into the through hole of the printed circuit board 4 through a slit 2b of the locking protrusion 2a, reach the soldering side, and are fixedly connected to the circuit pattern of the printed circuit board 4 with a solder 5. Accordingly, in this configuration, the bobbin 2 is eventually fixed to the printed circuit board 4 by using the component lead terminals 3a and fixing the bobbin to the component lead terminals 3a.
• a resin locking protrusion 2a is formed in the lower part of the side surface of the bobbin 2, and the locking protrusion 2a and the lead terminal 3a located inside the slit 2b are thermally fused under a pressure applied in the direction shown by an arrow so as to press them together.
• the component lead terminal 3a was fixed to the printed circuit board 4 with the solder 5, and the locking protrusion 2a is thermally fused to the component lead terminal 3a.
• the bobbin 2 comprising the transformer was eventually fixed to the printed circuit board 4 in a simple manner, it was not necessary to provide the primary winding connection pin 87, secondary winding connection pin 88, heater winding connection pin 89, and ground connection pin 90 separately at the bottom of the transformer 72, such as shown in FIG. 8, and operability was improved.
• the printed circuit board 4 was thereafter subjected to a drop test, it was found that certain improvements have to be made.
• the locking protrusion 2a of the bobbin 2 was thermally fused by sandwiching the lead terminal 3a, the locking protrusion 2a was pressed in the direction of simple sandwiching of the lead terminal 3a and could be easily moved in the longitudinal direction of the lead terminal 3a.
• the lead terminal 3a was fixed to the printed circuit board 4 by soldering to the printed circuit board 4 with the solder 5. Further, because the bobbin 2 comprising the core is the heaviest load on the printed circuit board 4, if the printed circuit board 4 is subjected to a drop test, a force trying to separate the bobbin from the printed circuit board 4 acts between the bobbin 2 and the printed circuit board 4. Further, because the bobbin 2 could move easily in the longitudinal direction of the lead terminal 3a, the bobbin 2 moved upward in the longitudinal direction of the lead terminal 3a and the place with weak joining, for example, the electric wiring between the bobbin 2 and component lead terminal 3a was broken. Further, when the heavy bobbin 2 again fell on the printed circuit board 4, the printed circuit board was fractured.
• ⁇ Disclosure of Invention> it is an object of the present invention to provide a printed circuit board carrying a transformer unit in which fracture of the printed circuit board can be prevented by making sure that the bobbin 2 cannot move in the longitudinal direction of the lead terminal 3a and that the electric wiring between the bobbin 2 and the component lead terminal 3a is not broken even when the printed circuit board 4 is subjected to a drop test.
• the present invention provides a printed circuit board carrying a transformer unit, in which a transformer unit comprising a transformer composed of a bobbin having wound thereon at least a primary winding and a secondary winding and a core inserted into the center of the bobbin and an electric component held in the outer peripheral region of the bobbin and/or the transformer is placed on a printed circuit board, lead terminals of the electric component are soldered to the printed circuit board, and the lead terminals are sandwiched in a slit formed in the bobbin and fixedly attached thereto, wherein a bent portion for preventing the bobbin from sliding, while sandwiching the lead terminal, with respect to at least one lead terminal in the longitudinal direction thereof is formed in the terminal.
• the invention according to claim 2 provides the printed circuit board carrying a transformer unit, according to claim 1, wherein the portion of the lead terminal which is sandwiched in the slit or portions at the side opposite the printed circuit board from the slit are formed to have an S-, V-, or U-like shape. Because the bobbin is thus reliably fixed to the printed circuit board, the bobbin does not move even if the drop test is conducted. Therefore, the printed circuit board is prevented from fracture.
• providing the component holding portion for holding the component in the outer peripheral region of the transformer and holding the high-voltage component in this component holding portion makes it possible to avoid mounting the high-voltage components on the printed circuit board.
• the transformer unit is fixed to the printed circuit board by using the lead terminals of the component and a bent portion for preventing the bobbin from sliding, while sandwiching the lead terminal, in the longitudinal direction of the lead terminal is formed at the lead terminal, the transformer unit is reliably fixed to the printed circuit board.
• the transformer unit does not move even if the drop test is implemented. Therefore, the printed circuit board is prevented from fracture.
• FIGs. 1A to 1C are schematic views of the printed circuit board carrying a transformer unit of the first embodiment of the present invention, FIG. 1A is a perspective view, FIG. IB is an enlarged cross-sectional view illustrating the process of fixing the bent portion by thermal fusion, and FIG. 1C is an enlarged perspective view illustrating the process of fixing the bent portion by upsetting;
• FIGs. 2A and 2B are schematic drawings illustrating the printed circuit board carrying a transformer unit of the prior invention, FIG. 2A is the perspective view thereof, and
• FIG. 2B is an enlarged cross-sectional view of the zone in the vicinity of a slit portion;
• FIGs. 3A and 3B are perspective views illustrating a drop test of the printed circuit board,
• FIG. 3A is a perspective view illustrating a drop test of the printed circuit board carrying a transformer unit of the present invention and
• FIG. 3B is a perspective view illustrating a drop test of the printed circuit board carrying a transformer unit of the prior invention;
• FIGs. 4A and 4B illustrate a component lead terminal of the second and third embodiment of the present invention
• FIG. 4A illustrates the second embodiment, and FIG. 4B illustrates the third embodiment
• FIG. 5 is a perspective view illustrating the conventional transformer unit disposed in a high-frequency heating device
• FIG. 6 is a circuit diagram illustrating the circuit configuration of a transformer unit
• FIG. 7 is a schematic cross-sectional view illustrating the structure of a transformer mounted on a transformer unit
• FIG. 8 is a perspective view illustrating the structure of a transformer, as viewed from the bottom surface thereof
• FIGs. 9A and 9B are a cross-sectional view and a side view of a transformer illustrating the structure of the transformer in accordance with the present invention
• FIG. 10 is a perspective view of the transformer illustrating the transformer structure
• FIG. 11 is a perspective view of a transformer unit illustrating the structure of a transformer unit having a transformer mounted thereon.
• a reference numeral 1 refers to a printed circuit board carrying a transformer unit of the first embodiment of the present invention
• 2 to a bobbin comprising a transformer
• 2a to a locking protrusion
• 2a_l to a V-shaped locking protrusion
• 2a_2 to a V-shaped recess
• 2b to a V-shaped slit
• 3 to an electric component held in the outer peripheral region of the bobbin and/or transformer
• 3a, 3d to a component lead terminal 4 to a printed circuit board; and 5 to a solder.
• FIGs. 1A to 1C are schematic views of the printed circuit board carrying a transformer unit of the first embodiment of the present invention
• FIG. 1A is a perspective view
• FIG. is an enlarged cross-sectional view illustrating the process of fixing the bent portion by thermal fusion
• FIG. 1C is an enlarged perspective view illustrating the process of fixing the bent portion by upsetting.
• the reference numeral 1 stands for a printed circuit board carrying a transformer unit of the first embodiment of the present invention
• 2 - a bobbin of the transformer unit comprising a transformer this bobbin being schematically shown as a rectangular parallelepiped.
• Locking protrusions 2a for locking the component lead terminals are formed in a plurality of locations in the lower part of the side surface of the bobbin 2, and the below- described V-shaped slits 2b are formed in the locking protrusions 2a.
• the reference numeral 3 stands for an electric component (diode, capacitor, or the like) held in the outer peripheral region of the bobbin and/or transformer.
• the reference numeral 3a stands for a lead terminal of the component 3.
• the component lead terminals 3a themselves can be formed in advance to have a V-like shape such that matches the V-like shape of the V-shaped slit 2b. Further, the strength is increased by thermally fusing the resin locking protrusion 2a and the lead terminal 3a located inside the V-shaped slit 2b in this state under a pressure applied in the direction shown by an arrow so as to press them together.
• FIG. 1C illustrates a simple fixing method employed instead of the method shown in FIG. IB.
• a V-shaped locking protrusion 2a_l made from a hard insulating material and a V- shaped recess 2a 2 also made from a hard insulating material for accommodating the V-shaped locking protrusion 2a_l are disposed opposite each other via a slit spacing in the lower part of bobbin 2, the slit portion of the component lead terminal 3a is inserted in this slit 2b and the V-shaped locking protrusion 2a_l is upset toward the V-shaped recess 2a_2 from the direction shown by an arrow, thereby reliably fixing the bobbin 2 to the printed circuit board 4 and operability is further improved.
• FIGs. 4A and 4B illustrates a component lead terminal of the second and third embodiment of the present invention
• FIG. 4A illustrates the second embodiment
• FIG. 4B illustrates the third embodiment
• the reference numeral 2a stands for a locking protrusion
• 3a refers to a lead terminal
• 4 refers to a printed circuit board
• 5 refers to a solder.
• the lead terminal 3a has a U-like shape.
• a recess is formed in the locking protrusion 2a located opposite the lead terminal.
• the bobbin 2 is prevented from even slightly moving in the longitudinal direction of the lead terminal 3a, the electric wiring between the bobbin 2 and component lead terminal 3a is prevented from breaking, and the printed circuit board 4 is fully protected from fracture if a heavy bobbin 2 falls again on the printed circuit board 4.
• the reference numeral 2a stands for a locking protrusion
• 3d refers to a lead terminal
• 4 refers to a printed circuit board
• 5 refers to a solder.
• the lead terminal 3d has a S-like shape, and a slit identical to that of the prior invention is formed in the locking protrusion 2a. As a result, production is simplified with respect to that of the first and second embodiments, because the V-like or U-like shape of the locking protrusion 2a are not required.
• the S-like shape of the lead terminal 3d provides for a resistance function preventing the bobbin 2 (therefore, 2a) from sliding in the longitudinal direction of the lead terminal 3d.
• the transformer in accordance with the present invention and the transformer unit equipped therewith providing the component holding portion for holding the component in the outer peripheral region of the transformer and holding the high-voltage component in this component holding portion makes it possible to avoid mounting the high-voltage components on the printed circuit board. Furthermore, because the transformer unit is fixed to the printed circuit board by using the lead terminals of the component and a bent portion for preventing the bobbin from sliding, while sandwiching the lead terminal, in the longitudinal direction of the lead terminal is formed at the lead terminal, the transformer unit is reliably fixed to the printed circuit board. The transformer unit does not move even if the drop test is implemented. Therefore, the printed circuit board is prevented from fracture.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Manufacturing & Machinery (AREA)
• Coils Of Transformers For General Uses (AREA)
• Control Of High-Frequency Heating Circuits (AREA)
• Housings And Mounting Of Transformers (AREA)
• Structures For Mounting Electric Components On Printed Circuit Boards (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=33562636

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (4)

Family Cites Families (1)

• 2003
  • 2003-07-04 JP JP2003271009A patent/JP3901669B2/ja not_active Expired - Fee Related
• 2004
  • 2004-06-29 WO PCT/JP2004/009499 patent/WO2005004176A1/en active Application Filing
  • 2004-06-29 CN CN200480016711.2A patent/CN1806301B/zh not_active Expired - Lifetime

Patent Citations (4)

Non-Patent Citations (1)

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