Light sensitive thyristor

Claim 2

In a light-sensitive thyristor comprising: a semiconductor wafer, having a light receiving plane, and consisting of first, second, third and fourth successive adjacent regions, each having a conductivity opposite to that of an adjacent region; a metallic base member for electro-conductively supporting said wafer; a pair of leads, each being electro-conductively connected to said first region and said second region, and a lead being electro-conductively connected to said fourth region; and a case member isolating said wafer from the atmosphere and having a transparent window through which an ignition light signal is projected by a light source onto the light receiving plane of said wafer, so as to turn on the thyristor; the improvement wherein: at least said second and third regions of said semiconductor wafer are co-planar with the outer surface of said first region forming said light receiving plane, at least the two junctions between said first and second regions and between said second and third regions extend to said light receiving plane, and the area of the surface of said first region is about 10 to 25 percent of the total area of the surfaces of said second and third regions exposed at said light receiving plane.

Claim 3

In a light-sensitive thyristor comprising: a semiconductor wafer, having a light receiving plane, and consisting of first, second, third and fourth successive adjacent regions, each having a conductivity opposite to that of an adjacent region; a metallic base member for electro-conductively supporting said wafer; a pair of leads, each being electro-conductively connected to said first region and said second region, and a lead being electro-conductively connected to said fourth region; and a case member isolating said wafer from the atmosphere and having a transparent window through which an ignition light signal is projected by a light source onto the light receiving plane of said wafer, so as to turn on the thyristor; the improvement wherein: at least said second and third regions of said semiconductor wafer are co-planar with the outer surface of said first region forming said light receiving plane, at least the two junctions between said first and second regions and between said second and third regions extend to said light receiving plane, and the area of the surface of said first region is about 10 to 25 percent of the total area of the surfaces of said second and third regions exposed at said light receiving plane.

Claim 4

In a light-sensitive thyristor comprising: a semiconductor wafer, having a light receiving plane, and consisting of first, second, third and fourth successive adjacent regions, each having a conductivity opposite to that of an adjacent region; a metallic base member for electro-conductively supporting said wafer; a pair of leads, each being electro-conductively connected to said first region and said second region, and a lead being electro-conductively connected to said fourth region; and a case member isolating said wafer from the atmosphere and having a transparent window through which an ignition light signal is projected by a light source onto the light receiving plane of said wafer, so as to turn on the thyristor; the improvement wherein: at least said second and third regions of said semiconductor wafer are co-planar with the outer surface of said first region forming said light receiving plane, at least the two junctions between said first and second regions and between said second and third regions extend to said light receiving plane, and the area of the surface of said first region is about 10 to 25 percent of the total area of the surfaces of said second and third regions exposed at said light receiving plane.

Claim 5

The improvement in a light-sensitive thyristor according to claim 1, wherein a free surface of said light receiving plane is coated with a film for preventing light scattering.

Claim 6

The improvement in a light-sensitive thyristor according to claim 1, wherein a surface of said first region is coated with a metallic film to which said lead to be connected to said first region is connected.

Claim 7

In a light-sensitive thyristor comprising: a semiconductor wafer, having a light receiving plane, and consisting of first, second, third and fourth successive adjacent regions, each having a conductivity opposite to that of an adjacent region, thereby forming a first junction between said first and second regions, a second junction between said second and third regions, and a third junction between said third and fourth regions; a metallic base member for electro-conductively supporting said wafer; a pair of leads, each being electro-conductively connected to said first region and said second region, and a lead being electro-conductively connected to said fourth region; and a case member isolating said wafer from the atmosphere and having a transparent window through which an ignition light signal is projected by a light source onto the light receiving plane of said wafer, so as to turn on the thyristor; the improvement wherein: each edge of said junctions extends to the light receiving plane and the area defined by the edge of the first junction is about 10-25 percent of the total area defined by edges of said second and third junctions.

Claim 8

In a light-sensitive thyristor comprising: a semiconductor wafer, having a light receiving plane, and consisting of first, second, third and fourth successive adjacent regions, each having a conductivity opposite to that of an adjacent region, thereby forming a first junction between said first and second regions, a second junction between said second and third regions, and a third junction between said third and fourth regions; a metallic base member for electro-conductively supporting said wafer; a pair of leads, each being electro-conductively connected to said first region and said second region, and a lead being electro-conductively connected to said fourth region; and a case member isolating said wafer from the atmosphere and having a transparent window through which an ignition light signal is projected by a light source onto the light receiving plane of said wafer, so as to turn on the thyristor; the improvement wherein: each edge of said junctions extends to the light receiving plane and the area defined by the edge of the first junction is about 10-25 percent of the total area defined by edges of said second and third junctions.

Claim 9

In a light sensitive thyristor device comprising: a light source for directing a beam of light onto a surface of a semiconductor wafer; a semiconductor wafer having a light receiving plane, and consisting of first, second, third and fourth successive regions, each region having a conductivity opposite to that of an adjacent region, forming a first junction between said first and second regions, a second junction between said second and third regions, and a third junction between said third and fourth regions in the wafer; a metallic base member for electro-conductively supporting said wafer; a pair of leads each being electro-conductively connected to said first region and said second region, and a lead being electro-conductively connected to said fourth region; and a case member isolating said wafer from the atmosphere and having a transparent window through which said light beam is projected by said light source to said light receiving plane; the improvement wherein: each edge of said junctions extends to said light receiving plane, and the area defined by the edge of said first junction is about 10 to 25 percent of the total area defined by the edges of said second and third junctions.

Claim 10

In a light sensitive thyristor device comprising: a light source for directing a beam of light onto a surface of a semiconductor wafer; a semiconductor wafer having a light receiving plane, and consisting of first, second, third and fourth successive regions, each region having a conductivity opposite to that of an adjacent region, forming a first junction between said first and second regions, a second junction between said second and third regions, and a third junction between said third and fourth regions in the wafer; a metallic base member for electro-conductively supporting said wafer; a pair of leads each being electro-conductively connected to said first region and said second region, and a lead being electro-conductively connected to said fourth region; and a case member isolating said wafer from the atmosphere and having a transparent window through which said light beam is projected by said light source to said light receiving plane; the improvement wherein: each edge of said junctions extends to said light receiving plane, and the area defined by the edge of said first junction is about 10 to 25 percent of the total area defined by the edges of said second and third junctions.

Claim 11

In a light-sensitive thyristor comprising: a semiconductor wafer including means, responsive to the impingement of light thereon, for triggering a current conductivity path through said semiconductor wafer, said means comprising a predetermined portion of a light receiving plane of said wafer, said wafer consisting of first, second, third and fourth successive adjacent regions, each hAving a conductivity opposite to that of an adjacent region; a metallic base member for electro-conductively supporting said wafer; a pair of leads, each being electro-conductively connected to said first region and said second region, and a lead being electro-conductively connected to said fourth region; and a case member isolating said wafer from the atmosphere and having a transparent window through which an ignition light signal is projected by a light source onto said predetermined portion of the light receiving plane of said wafer, so as to turn-on said thyristor by the provision of said current conducting path through said wafer; the improvement wherein: at least said second and third regions of said semiconductor wafer are co-planar with the outer surface of said first region forming said predetermined portion of the light receiving plane of said wafer, onto which light for triggering said thyristor is to be directed, at least the two junctions between said first and second regions and between said second and third regions extend to said predetermined portion of the light receiving plane, and the area of the surface of said first region is about 10 to 25 percent of the total area of the surfaces of said second and third regions exposed in said predetermined portion of said light receiving plane.

Claim 12

In a light-sensitive thyristor comprising: a semiconductor wafer including means, responsive to the impingement of light thereon, for triggering a current conductivity path through said semiconductor wafer, said means comprising a predetermined portion of a light receiving plane of said wafer, said wafer consisting of first, second, third and fourth successive adjacent regions, each hAving a conductivity opposite to that of an adjacent region; a metallic base member for electro-conductively supporting said wafer; a pair of leads, each being electro-conductively connected to said first region and said second region, and a lead being electro-conductively connected to said fourth region; and a case member isolating said wafer from the atmosphere and having a transparent window through which an ignition light signal is projected by a light source onto said predetermined portion of the light receiving plane of said wafer, so as to turn-on said thyristor by the provision of said current conducting path through said wafer; the improvement wherein: at least said second and third regions of said semiconductor wafer are co-planar with the outer surface of said first region forming said predetermined portion of the light receiving plane of said wafer, onto which light for triggering said thyristor is to be directed, at least the two junctions between said first and second regions and between said second and third regions extend to said predetermined portion of the light receiving plane, and the area of the surface of said first region is about 10 to 25 percent of the total area of the surfaces of said second and third regions exposed in said predetermined portion of said light receiving plane.

Claim 13

The improvement in a light-sensitive thyristor according to claim 6, wherein a free surface of said light receiving plane is coated with a film for preventing light scattering.

Claim 14

The improvement in a light-sensitive thyristor according to claim 6, wherein a surface of said first region is coated with a metallic film to which said lead to be connected to said first region is connected.

Claim 15

The improvement in a light-sensitive thyristor according to claim 7, wherein a surface of said first region is coated with a metallic film to which said lead to be connected to said first region is connected.