| 摘要 |
PURPOSE:To eliminate distortions on the surface of a surface acoustic wave SAW caused by the difference of SAW speeds between an electrode part and a non-electrode part and therefore to improve daterioration of characteristics due to said SAW distortions with a SAW device, by using an electrode plate containing many small non-electrode gaps at an area equivalent to a conventional dummy electrode. CONSTITUTION:A mesh electrode part 5 is provided between a weighting electrode part 4 and a draw-out electrode part 6. The part 5 contains many non-electrode gaps 7 in a mesh form and these gaps 7 are formed so that the even value is secured among metallic parts serving as electrodes in the SAW transmitting direction. Thus the total SAW transmitting speed is kept at a constant level to eliminate distortions produced on the SAW surface and therefore no deterioration of characteristics is caused. In addition, the small holes 7 are periodically formed or the sizes of these holes 7 are set smaller enough that the SAW length. As a result, the SAW reflection is reduced and therefore the deterioration of characteristics due to the SAW reflection is extremely reduced. Furthermore the defects due to disconnections of electrodes are greatly reduced in comparison with a conventional case where both the electrode 4 and a dummy electrode are formed in the electrode pieces since the electrode 5 is formed in a mesh form. Then the production yield is improved with a SAW device.
|
