Abstract:
The invention provides an improved process for fabricating devices containing metallized magnetic ceramic material, such as inductors, transformers, and magnetic substrates. In particular, the unique vias utilized in the process of the invention allow fabrication of devices from multiple unfired ferrite layers with only a single via-coating step, thereby avoiding the need numerous punching steps. Moreover, there is no need for expanding the dimensions of the vias and thus no need for internal metallization. The invention therefore provides for green tape-type fabrication of devices such as inductors, transformers, and magnetic substrates in a manner faster, less complex, and more reliable than current methods. The invention also relates to use of an improved conductive material in such a process, the conductive material containing silver/palladium particles, ferrite particles, a cellulose-based or other organic binder, and a solvent. After firing of the substrate onto which the ink has been coated, and plating of copper thereon by a copper pyrophosphate bath, the plated copper exhibits a pull strength greater than about 4 kpsi, advantageously greater than about 5 kpsi. Use of a copper pyrophosphate bath also allow uniform plating within long, narrow vias.
Abstract:
Conventional optical gratings are relatively temperature sensitive. This sensitivity is generally undesirable but can be reduced or eliminated by attaching the grating to a support member (11) having a negative coefficient of thermal expansion. Exemplarily the member comprises Zr-tungstate and/or Hf-tungstate. The thermal expansion can be tailored by admixture of positive expansion coefficient material (e.g., Al 2 O 3 , SiO 2 ) to the negative expansion coefficient material (e.g., ZrW 2 O 8 ), or by a variety of other techniques.
Abstract translation:常规光栅相对温度敏感。 这种灵敏度通常是不希望的,但可以通过将光栅附着到具有负热膨胀系数的支撑构件(11)来减小或消除。 示例性地,该构件包含Zr钨酸盐和/或Hf钨酸盐。 热膨胀可以通过将正膨胀系数材料(例如,Al 2 O 3,SiO 2)与负膨胀系数材料(例如ZrW 2 O 8)混合或通过各种其他技术来调整。
Abstract:
The invention provides an improved process for fabricating devices containing metallized magnetic ceramic material, such as inductors, transformers, and magnetic substrates. In particular, the unique vias utilized in the process of the invention allow fabrication of devices from multiple unfired ferrite layers with only a single via-coating step, thereby avoiding the need numerous punching steps. Moreover, there is no need for expanding the dimensions of the vias and thus no need for internal metallization. The invention therefore provides for green tape-type fabrication of devices such as inductors, transformers, and magnetic substrates in a manner faster, less complex, and more reliable than current methods. The invention also relates to use of an improved conductive material in such a process, the conductive material containing silver/palladium particles, ferrite particles, a cellulose-based or other organic binder, and a solvent. After firing of the substrate onto which the ink has been coated, and plating of copper thereon by a copper pyrophosphate bath, the plated copper exhibits a pull strength greater than about 4 kpsi, advantageously greater than about 5 kpsi. Use of a copper pyrophosphate bath also allow uniform plating within long, narrow vias.
Abstract:
A transformer (FIG. 1) optimized for surface-mount vacuum-pickup automated circuit assembly eliminates the expense of a transformer housing. The transformer has a ferrite body (100) that defines a pair of wells (208, 209) each opening onto an opposite face (108, 109) of the ferrite body. Transformer primary and secondary windings are wound in a coil (103) through slots (210, 211) around a transformer core (204) at the bottom of the wells. The windings do not protrude from the wells beyond the faces, resulting in flat faces. A first plurality of conductive vias (104-106), one pair for each winding, are completely embedded in the ferrite body and extend to both of the faces. Each pair of vias serves at one face to attach to the winding and at the other face to attach to solder pods of a PC board. The embedded vias also serve as EMI filters. A plate (107) covers the one face and provides a surface for vacuum pickup and for labeling of the transformer. The ferrite body (500) of a first transformer (FIG. 5) adapted for stacked mounting of transformers dispenses with the flat plate and further defines a second plurality of pairs of conductive vias (104-106). These vias are not connected to the first transformer's windings, but rather are positioned for connection to the winding-connected first pairs of vias of a second transformer that is positioned orthogonally to and mounted on the first transformer at the one of the faces.
Abstract:
Conventional optical gratings are relatively temperature sensitive. This sensitivity is generally undesirable but can be reduced or eliminated by attaching the grating to a support member (11) having a negative coefficient of thermal expansion. Exemplarily the member comprises Zr-tungstate and/or Hf-tungstate. The thermal expansion can be tailored by admixture of positive expansion coefficient material (e.g., Al 2 O 3 , SiO 2 ) to the negative expansion coefficient material (e.g., ZrW 2 O 8 ), or by a variety of other techniques.