Abstract: A light emitting device includes a first active region, a second active region, and a tunnel junction. The tunnel junction includes a layer of first conductivity type and a layer of second conductivity type, both thinner than a layer of first conductivity type and a layer of second conductivity type surrounding the first active region. The tunnel junction permits vertical stacking of the active regions, which may increase the light generated by a device without increasing the size of the source.

Abstract: A method of forming a photoresist mask on a light emitting device is disclosed. A portion of the light emitting device is coated with photoresist. A portion of the photoresist is exposed by light impinging on the interface of the light emitting device and the photoresist from inside the light emitting device. The photoresist is developed, removing either the exposed photoresist or the unexposed photoresist. In one embodiment, the photoresist mask may be used to form a phosphor coating. After the photoresist is developed to remove the exposed photoresist, a phosphor layer is deposited overlying the light emitting device. The unexposed portion of photoresist is stripped. In some embodiments, the light exposing the photoresist is produced by electrically biasing the light emitting device, or by shining light into the light emitting device through an aperture or by a focussed laser.

Abstract: A light emitting diode printhead has a row of LED dice, with each die having one or more rows of LEDs. The LED die substrate forms a common cathode for the LEDs on that die. There is a time multiplex driver for a plurality of dice comprising a plurality of current sources. Each current source comprises a current driver FET and a data FET in series. Each data FET is connected in parallel to the anodes of corresponding LEDs on all of the dice. Switches selectively connect the substrate of each die to ground. A latching shift register is used for applying data for a selected die to the data FETs. The register is divided into the same number of blocks as the number of dice, and each block has the same number of bits as the LEDs on a die. At the same time a block of data for a selected die is connected to the data FETs, the substrate of the selected die is connected to ground, thereby enabling only the light emitting diodes on the selected die.

Abstract: An improved and more versatile, variable capotasto for multistringed instruments, such as guitars, banjos, mandolins and the like. This capotasto is attached to the neck of an instrument by a resilient strap, containing eyelets for adjustment expediently from fret to fret positions. Optionally, a spring loaded or thumb screw adjustable clamp can be made onto the capotasto in order to attach it to an instrument. The unit consists of a Mounting Block which contains 6 (for guitars) spring-tensioned Plungers with padded tips. The Mounting Block also supports a sub-system of 6 vertically installed Cam Levers, each of which respectively can cause any one of the 6 Plunger's tips to press upon an instrument's string behind a fret bar. Hence, this allows the musician to conveniently and quickly change the pitch of any or all strings with this capotasto. The 6 strings can be selectively changed to any combination of open or muted notes, as well as augmenting a multiplicity of open and bar chords.