Abstract: A keyboard without ghost keys has a circuit which includes a microprocessor in which a plurality of I/O lines form a keyboard scanning matrix. Two of the I/O lines on the matrix cross to define a plurality of signal switches. The microprocessor is electrically connected to a primary level resistance and a reference potential to determine the ON condition of the signal switches. Each signal switch further is electrically connected to at least one secondary level switch which is electrically connected to the primary level switch in a serial manner. When a user depresses any three signal switches on the rectangular angles of the keyboard scanning matrix, the connecting primary level resistance and the secondary level resistance form a new level resistance. The new level resistance and the current flowing to the keyboard scanning matrix are processed to get a potential smaller than the reference potential, thereby to eliminate the phenomenon of ghost keys.

Abstract: A keyboard without ghost keys has a circuit which includes a microprocessor in which a plurality of I/O lines form a keyboard scanning matrix. Two of the I/O lines on the matrix cross to define a plurality of signal switches. The microprocessor is electrically connected to a primary level resistance and a reference potential to determine the ON condition of the signal switches. Each signal switch further is electrically connected to at least one secondary level switch which is electrically connected to the primary level switch in a serial manner. When a user depresses any three signal switches on the rectangular angles of the keyboard scanning matrix, the connecting primary level resistance and the secondary level resistance form a new level resistance. The new level resistance and the current flowing to the keyboard scanning matrix are processed to get a potential smaller than the reference potential, thereby to eliminate the phenomenon of ghost keys.

Abstract: A pushbutton mechanism for keyboards includes a bridge in a pushbutton that has an inner frame and an outer frame to make the pushbutton movable up and down. The inner frame and outer frame are intersected and coupled together, and have respectively inner side brackets and outer side brackets that have a stub shaft and a pivot portion to form a relative turning relationship. The inner and outer side brackets have respectively harness bosses and harness recesses corresponding to each other to allow the pushbutton to form a lifting position and a lower position in normal conditions. The bridge thus formed can generate a steadier relative turning and confine the stroke distance for the pushbutton.

Abstract: A method for configuring button keys on a membrane includes the steps of: mapping the membrane under the conditions of without jumping and without generating ghost keys; gathering adjacent button keys on a same cluster; defining a button key configuration chart according to each cluster; and linking circuits of each button key in each cluster to a flat cable of the membrane. Then defining total number of various composite keys; locating the composite keys to be not co-linear or cross co-linear on the X-axis or the Y-axis of the matrix scanning lines; and mapping other adjacent button keys without the jumping.

Abstract: A keyboard key capable of lowering its overall height, which comprises a key cap body and a key cap base being coupled to the keyboard and disposed at the areas of four corners correspondingly having a displacing pillar and elevating groove, and an accommodating section of an electrically conductive cap body disposed at the corresponding central position of the key cap base and the key cap body, and a fixing section and a positioning section coupled to the key cap body and the key cap base respectively, and the displacing pillar and elevating groove are disposed separately at the four corners to reduce the moment of any point of the key cap body pressing the electrically conductive cap body in order to achieve the purposes of effectively lowering the overall height of the key and making the keyboard thin.

Abstract: A waterproof structure is used with a printed circuit board, which is primarily composed of an upper layer membrane, a lower layer membrane, and an insulation layer, which are conjoined to one another. Besides, at least one first channel and second channel are provided on the upper layer membrane and the lower layer membrane respectively and correspondingly. Also, a pressure-adjusting hole, whose periphery is larger than that of the first channel and the second channel, is provided on the insulation layer corresponding to the positions of the first channel and the second channel. After the first channel, the second channel, and the pressure-adjusting hole of the insulation layer have been conjoined, a waterproof unit will be formed at a place where the contact points of the three are not connected to one another. The waterproof unit contains circulated air and prevents moisture from permeating into the circuit board thereby avoiding a short circuit of the circuit board.

Abstract: A method for manufacturing membranes after having defined the button key position circuit and matrix layout under the conditions of without jumping and without generating ghost keys includes the steps of: heating and pre-shrinking the PET of a membrane, printing a circuit made from silver paste on the membrane, printing an insulation layer on the printed silver paste circuit or printing carbon powders, folding the membrane and welding the membrane by supersonic wave, and finally punching structural holes on the membrane to complete the membrane production.

Abstract: The invention provides an improved waterproof structure of a printed circuit board. The printed circuit board is primarily composed of an upper layer membrane, a lower layer membrane, and an insulation layer, which are conjoined to one another. Besides, at least one first channel and second channel are provided on the upper layer membrane and the lower layer membrane respectively and correspondingly. Also, a pressure-adjusting hole, whose diameter is larger than that of the first channel and the second channel, is provided on the insulation layer corresponding to the positions of the first channel and the second channel. After the first channel, the second channel, and the pressure-adjusting hole of the insulation layer have been conjoined, a waterproof unit will be formed at a place where the contact points of the three are not connected to one another. The waterproof unit contains circulated air and prevents moisture from permeating into the circuit board to cause short circuit on the circuit board.

Abstract: A method for configuring button keys on a membrane includes the steps of: mapping the membrane under the conditions of without jumping and without generating ghost keys; gathering adjacent button keys on a same cluster; defining a button key configuration chart according to each cluster; and linking circuits of each button key in each cluster to a flat cable of the membrane. Then defining total number of various composite keys; locating the composite keys to be not co-linear or cross co-linear on the X-axis or the Y-axis of the matrix scanning lines; and mapping other adjacent button keys without the jumping.

Abstract: A method for manufacturing membranes after having defined the button key position circuit and matrix layout under the conditions of without jumping and without generating ghost keys includes the steps of: heating and pre-shrinking the PET of a membrane, printing a circuit made from silver paste on the membrane, printing an insulation layer on the printed silver paste circuit or printing carbon powders, folding the membrane and welding the membrane by supersonic wave, and finally punching structural holes on the membrane to complete the membrane production.