Title:
MULTILAYER PRINTED WIRING BOARD
Document Type and Number:
Japanese Patent JP3669219
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain a multilayer printed wiring board which suppresses unwanted electromagnetic waves.
SOLUTION: This wiring board has at least two signal wiring layers 1, 4, a ground layer 2 and a power source layer 3 and comprises a signal wiring 9 on the signal wiring layer 4 far from a ground layer 2 and a ground wiring 10 adjacent to the same layer, thereby forming the return path of a signal current flowing on the signal wiring 9. In this structure, the return current path is ensured adjacent to the signal current path, and the signal wiring provides a low impedance against the ground plane, thus enabling current return with a shorter closed loop. Thus loops traced by signal currents flowing to the ground over all the signal wirings on the printed wiring board and return currents thereof can be made small to suppress radiation of unwanted electromagnetic waves. Loops, traced by signal currents continuously flowing to the ground over all the signal wirings on two or more different layers connected via the through-holes and return currents thereof can also be made small.
More Like This:
Inventors:
Kenji Kamiya
Application Number:
JP22698699A
Publication Date:
July 06, 2005
Filing Date:
August 10, 1999
Export Citation:
Assignee:
NEC
International Classes:
H05K9/00; H05K1/02; H05K3/46; H05K1/00; H05K3/42; (IPC1-7): H05K3/46; H05K1/02; H05K9/00
Domestic Patent References:
| JP3205897A | ||||
| JP11163539A | ||||
| JP62259500A | ||||
| JP9321433A |
Attorney, Agent or Firm:
Takao Maruyama
Previous Patent: JOB SITE IMAGE MANAGING DEVICE
Next Patent: CLEANING DEVICE, IMAGE FORMING DEVICE AND ITS MANUFACTURE
Next Patent: CLEANING DEVICE, IMAGE FORMING DEVICE AND ITS MANUFACTURE