Abstract: An optical transmission system includes: a WDM transmission device configured to output WDM signal light including rays of a plurality of wavelengths; a wavelength converter configured to convert the WDM signal light into converted light in a different wavelength band; and a processor configured to control a signal level of the WDM signal light incident on the wavelength converter, wherein the processor controls the signal level of the WDM signal light so as to make the signal level of the WDM signal light decrease in a direction away from a wavelength of pump light used in the wavelength converter.

Abstract: A flux for soldering used when soldering is performed to a board subjected to electroless nickel plating, the flux containing resin having film forming ability, activator, and solvent, and further containing metallic salt in an amount of 0.1 to 20% by weight of the total amount of flux. The use of this flux suppresses diffusion of nickel solder in soldering portions, and prevents concentration of phosphorous, thereby improving the bonding strength of soldering.

Abstract: The present invention is a method to manufacture the SnZnNiCu solder powder through liquid quenching atomizing method, and an atomizing temperature is not less than 500° C., in particular, not less than 900° C. The raw material metal used as raw material of the solder powder comprises 3 to 12% by weight of Zn, 1.0 to 15% by weight of the sum of Cu and Ni, and Sn and inevitable impurities for the rest, to the total amount of raw material. Thereby, high joint strength is achieved and the SnZnNiCu solder powder which can improve joint reliability of solder joint part is provided.

Abstract: A flux for soldering used when soldering is performed to a board subjected to electroless nickel plating, the flux containing resin having film forming ability, activator, and solvent, and further containing metallic salt in an amount of 0.1 to 20% by weight of the total amount of flux. The use of this flux suppresses diffusion of nickel solder in soldering portions, and prevents concentration of phosphorous, thereby improving the bonding strength of soldering.

Abstract: The present invention is a method to manufacture the SnZnNiCu solder powder through liquid quenching atomizing method, and an atomizing temperature is not less than 500° C., in particular, not less than 900° C. The raw material metal used as raw material of the solder powder comprises 3 to 12% by weight of Zn, 1.0 to 15% by weight of the sum of Cu and Ni, and Sn and inevitable impurities for the rest, to the total amount of raw material. Thereby, high joint strength is achieved and the SnZnNiCu solder powder which can improve joint reliability of solder joint part is provided.

Abstract: A flux for soldering used when soldering is performed to a board subjected to electroless nickel plating, the flux containing resin having film forming ability, activator, and solvent, and further containing metallic salt in an amount of 0.1 to 20% by weight of the total amount of flux. The use of this flux suppresses diffusion of nickel solder in soldering portions, and prevents concentration of phosphorous, thereby improving the bonding strength of soldering.

Abstract: According to present invention, there is provided a lead-free solder precipitating composition comprising a tin powder, and a complex of silver ions and/or copper ions and aryl phosphines, alkyl phosphine, phosphines or azoles. The solder precipitating composition can form proper lead-free solder on lands of a circuit board, without forming silver and/or copper film on the circuit board.

Abstract: According to present invention, there is provided a lead-free solder precipitating composition comprising a tin powder, and a complex of silver ions and/or copper ions and aryl phosphines, alkyl phosphine, phosphines or azoles. The solder precipitating composition can form proper lead-free solder on lands of a circuit board, without forming silver and/or copper film on the circuit board.

Abstract: A plurality of pads are formed on a circuit board body at a pitch of 0.5 mm or less. The pads are formed such that a projecting height H of a pad from the board body surface and a width W of the pad satisfy a relation 2H<W, that a pad array is formed in which a width of each of the pads located at two ends of the pad array is larger than that of a pad located therebetween, and that the pad width W and a pad-to-pad distance D satisfy a relation W>D. A solder layer, obtained by a substitution reaction between a powder of a metal having the highest ionization tendency among metals constituting the solder layer or a powder of an alloy thereof and a salt formed by bonding the other metal or metals in the solder layer to an organic acid, is formed on each pad.

Abstract: A solder precipitating composition comprises a powder of a metal having the highest ionization level among metals constituting a solder alloy to be prepared, and a salt between a carboxylic acid and a remaining metal of the solder alloy. The composition is applied to a surface on which the solder is to be precipitated, and the solder is precipitated, thereby performing soldering.

Abstract: A paste-like composition containing a lead salt of an organic acid and tin powder is applied on a pad array portion of a circuit board. Then, the paste-like compsition is heated so as to cause precipitation, thereby forming a solder layer formed of a Sn-Pb alloy substantially only on the pads. This precipitation is performed in a state that a liquid pool is formed on the pad array portion when the paste-like composition is liquefied by heating, and the tin powder is settled in the liquid pool. When an electronic part is mounted on the pads, first, preparatory solder layers are formed on the pads by the above-mentioned precipitation process. After a paste-like composition is applied on the preparatory solder layers, the electronic part is put on the paste-like composition. Then, the paste-like composition is heated, thereby soldering leads of the electronic part to the pads.

Abstract: A method for forming a metal film on the surface of a substrate metal, which comprises soaking a substrate metal or a non-metal support carrying the substrate metal thereon in a solution of a metal salt in a high boiling point solvent under heating conditions, characterized in that the metal salt is a salt of the metal to be formed on the surface of the substrate metal with an acidic substance selected from an organic carboxylic acid, a rosin and a rosin derivative. The metal is precipitated from the solution exclusively on the surface of the substrate metal without forming any solid metal particle in the solution or on the substrate metal. Thus, the method is applicable to the formation of a soldering alloy as a film on the surface of a substrate metal without leaving thereon any free metal particle which may cause short circuits in electronic circuits.