A small, pocket size, direct current flat electroluminescent display panel ade of a single crystalline substrate having electroluminescent material on the front face and addressing circuitry on the back face. The addressing circuitry is conductively connected to the electroluminescent material through feedthrough holes in the substrate. The feedthrough holes are produced by electrons beams or laser beams, or by photo-etching techniques. The addressing circuitry may be, for example, metallic oxide semiconductors or thin film transistors. A large scale integrated thin film transistor circuit could be deposited into a matrix, from a multiple of evaporation sources, through a system of registered masks positioned on the back side of the substrate. The electroluminescent material may comprise a matrix of light emitting diodes, or alternatively a solid sheet of Group II-VI heterojunction sandwich structure. The matrix of light emitting diodes may be made of gallium arsenide phosphide materials that are in exact registration with the addressing circuitry and connected thereto by conductors connected through the feedthrough holes. Voltage pulses from shift registers in a predetermined pattern are applied to the matrix of addressing circuitry. Outputs from the addressing circuitry cause the electroluminescent material that is conductively connected thereto to conduct, providing a display in the predetermined pattern of the voltage pulses from the shift registers.

An alpha-numeric display panel with a matrix of amorphous semiconductors nted on a substrate. Each of the semiconductors comprises a vitreous material layer contiguous with an electroluminescent material layer. Metal electrodes with small metal islands positioned in the center of the electrodes and isolated therefrom are vapor deposited through a photoetched mask on each side of the vitreous material, or vitreous switching layer. The electrodes and islands are in exact registration on opposite sides of the vitreous switching layer. An electrically conductive layer is vapor deposited on one side of a glass substrate. The electroluminescent layer is contiguous with one side of the vitreous switching layer on one side and is contiguous with the electrically conductive layer on the opposite side. The matrix of amorphous semiconductors are connected to a voltage source, ground, and to bucket brigade shift registers, such that a display is generated according to video information transmitted to the read-out and matrix. The electrodes on the rear of the vitreous switching layer are connected to a positive direct current voltage source. The electrically conductive layer is connected to ground. The rear metal islands are connected to row shift registers, and the front metal islands are connected to the column shift registers. The column shift register has an overriding video signal thereon. The vitreous layer is biased close to, but less than, the amount required for conduction such that an increased voltage potential across the vitreous layer provided by the combination of the shift register and video signals causes the amorphous semiconductor to conduct and, therefore, the electroluminescent layer to luminesce providing a display at that element. Horizontal and vertical clock pulses, from the column and row shift registers, synchronously switch voltages to the rear and front metal islands until the entire panel has been scanned. The electroluminescent layers remain "on," thus displaying an alpha-numeric read-out, until the direct current voltage source is removed from the rear electrode.

In a printed circuit board, a safety means is provided to prevent the circuit elements such as semiconductor devices, resistors, and the like from suffering damage due to overcurrent flow. The safety means thus improved has a narrow gap provided within a metal foil pattern on the surface of the printed circuit board and a low-melting point metal such as solder bridges this gap to connect the metal foil.

An improved silicon building block is disclosed. In an embodiment, the silicon building block has at least two vias through it. The silicon building block is doped and the vias filled with a first material, and, optionally, selected ones of the vias filled instead with a second material. In an alternative embodiment, regions of the silicon building block have metal deposited on them.

An improved silicon building block is disclosed. In an embodiment, the silicon building block has at least two vias through it. The silicon building block is doped and the vias filled with a first material, and, optionally, selected ones of the vias filled instead with a second material. In an alternative embodiment, regions of the silicon building block have metal deposited on them.