Capacitor and method of manufacturing the same
A capacitor element includes a pair of conductive layer, a plurality of first electrodes and second electrodes, and insulation caps for insulating these electrodes from the conductive layers. By anodizing a metal substrate in two stages, holes filled with the first electrodes and holes filled with the second electrodes are randomly distributed.
1. A capacitor comprising:
a pair of conductive layers that are opposed to each other at a determinable interval;
a dielectric layer that is an anodic metal oxide interposed between the pair of conductive layers;
a plurality of first electrodes that are disposed in some of a plurality of holes passing through the dielectric layer in a direction substantially or nearly perpendicular to the pair of conductive layers, and have respective one end portions which are electrically connected to one of the conductive layers and respective another end portions which are insulated from another of the conductive layers;
and a plurality of second electrodes that are disposed in substantially all other of the plurality of holes other than the some of the plurality of holes, and have respective one end portions which are electrically connected to the another of the conductive layers and respective another end portions which are insulated from the one of the conductive layers,
wherein the individual first electrodes and the individual second electrodes have a diameter of several 10 nm to several 100 nm and are randomly distributed throughout the entire dielectric layer as viewed in the direction substantially or nearly perpendicular to the pair of conductive layers.
2. The capacitor according to claim 1 , wherein the dielectric layer is made of a material selected from the group consisting of oxides of valve metals, composite oxides, and resins.
3. The capacitor according to claim 2 , wherein at least the first or second electrodes are insulated from the respective conductive layers by cleavages provided between ends of the first and/or second electrodes and the respective conductive layers.
4. The capacitor according to claim 2 , wherein at least the first or second electrodes are insulated from the respective conductive layers by insulators provided between ends of the first and/or second electrodes and the respective conductive layers.
5. The capacitor according to claim 4 , wherein the insulators are made of a material selected from the group consisting of metal oxides, resins, and SiO 2 .
6. The capacitor according to claim 1 , wherein at least the first or second electrodes are insulated from the respective conductive layers by cleavages provided between ends of the first and/or second electrodes and the respective conductive layers.
7. The capacitor according to claim 1 , wherein at least the first or second electrodes are insulated from the respective conductive layers by insulators provided between ends of the first and/or second electrodes and the respective conductive layers.
8. The capacitor according to claim 7 , wherein the insulators are made of a material selected from the group consisting of metal oxides, resins, and SiO 2 .
9. The capacitor element according to claim 1 , wherein the first and second electrodes have a thickness of several 100 nm to several 100 μm.
10. The capacitor element according to claim 1 , further comprising lead wires connected to the pair of the conductive layers, respectively, wherein the capacitor element is entirely coated with an insulating film.