An optically activated keyboard provides inputs to a digital computer or the like. The keyboard includes a key housing having formed therein a wave guide matrix of intersecting columns and rows with light emitting diodes (LED's) installed in one end of each column and photo transistors installed in one end of each row. A plurality of keys are mounted at the top surface of the housing, each key having a plunger which projects through a corresponding aperture in the housing, when the key is depressed. The intersections of the columns and rows are located directly beneath the apertures so that when a key is depressed, its plunger intrudes into the volume at the intersection. Each plunger, in concert with the wave guide intersection, forms a light polarizing system. In the preferred embodiment, each plunger has a reflecting face that is angled to reflect light from the LED in the corresponding column into the corresponding row, finally impinging against the appropriate photo transistor. In this preferred embodiment, when the button is fully depressed, the plunger provides space between the bottom of the plunger and the bottom of the wave guide so that light traveling in the column or row is permitted to pass and thereby to detect any other keys that have been depressed in the particular column or row.
A manually operable touch pad for generating steering signals and enable signals for manipulating an image on a CRT display or for controlling the operation of plural motors whereby the image or object being driven can be positioned using appropriate hand/eye coordination. The touch pad comprises a box-like mounting base supporting a rectangular printed circuit board on which are mounted four opto-switches centered on the respective edges thereof. The printed circuit board also supports other circuit components and the necessary interconnecting conductors. Overlaying the base in covering relation with respect to the printed circuit board is a molded plastic top having a center post which depends downwardly from the underside thereof, passing through an apertrue in the printed circuit card and adaptive to be secured to the center of the base by a flexible coupling. Depending downwardly from the underside of the cover are four opaque projections positioned to selectively interrupt the passage of light energy in the four opto-switches. By manipulating the top member, it can be rocked in such a way that the trigger tabs can appropriately actuate the opto-switches and thereby produce the desired control signals.
A keyboard connectable to scanning means and constituted by an optical block comprising: a top face, a bottom face, and at least one edge interconnecting said faces; a plurality of light injection inlets (2) and a plurality of detection outlets (3) disposed so as to define optimum paths passing through said block between said top and bottom faces and establishing a logical matrix having intersections each of which associates one of said inlets and with one of said outlets; and reflectors (5) disposed at said intersections in order to couple the associated inlet/outlet paris; the keyboard being characterized in that said reflectors are fixed, in that said reflectors and the said optical paths going from the light injection inlets and arriving at said detection outlets are all at the same level; in that at least some of said optical paths cross one another physically at said level, and in that key-operatable shutters (4) are provided in order to allow, to limit, or to prevent at will the coupling established by each of said reflectors without obstructing the coupling established via other reflectors.
A method and apparatus for use with a keypad for an electronic device including at least one plunger associated with a key, wherein the plunger is moveable between a first position and a second position relative to the electronic device. The apparatus is an electrical assembly including a light guide, and at least one electrical component carried by the light guide and positioned to underlie the key for at least one of a) illuminating the key, and b) changing between a first electrical state and a second electrical state in response to the plunger being moved between the first and second positions to indicate that the key has been operated by a user.
To detect a faulty operation in a non-contact switch, a pulse signal is applied to the light emitting element of non-contact switch. The thus input pulse signal is compared with an output signal generated by a light receiving element of the non-contact switch. The faulty operation of the non-contact switch is discriminated in accordance with the thus compared input and output signals. Also to detect a faulty operation of the non-contact switch, a switch assembly includes a main push-button and an auxiliary push-button concentrically located over and within the main push-button. When the main push-button operates properly, the blocking members associated with the main push-button and the auxiliary push-button are displaced together. On the other hand, when the main push-button malfunctions, the light blocking member of the auxiliary push-button blocks the passage of light within the non-contact switch. Thus, an erroneous operation resulting from jamming of the main push-button is prevented.
To detect a faulty operation in a non-contact switch, a pulse signal is applied to the light emitting element of the non-contact switch. The input pulse signal is compared with an output signal generated by a light receiving element of the non-contact switch. The faulty operation of the non-contact switch is discriminated in accordance with the thus compared input and output signals.
