Multi-channel optical time-sharing apparatus having a rotating filter wheel with position-encoding means
First Claim
1. In a multi-wavelength optical instrument of the type including a plurality of optical channels provided with respective gain equalizer means and signal detection means, a rotating filter member having a plurality of wavelength filters spaced around its axis to define said optical channels and provided with a supporting shaft having a hollow portion, means to illuminate said hollow shaft portion internally, respective signal-generating photosensitive means associated with the gain equalizer means and the signal detection means mounted externally adjacent said hollow shaft portion, said hollow shaft portion having means formed to illuminate said respective photosensitive means so as to generate respective cyclic sets of long and short pulses, and means to decode said pulses to derive respective cyclic gating pulses for said gain equalizer means and signal detection means.
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Abstract
A multi-wavelength time-sharing apparatus usable in various different configurations of optical measuring equipment to provide a plurality of time-shared optical channels and including appropriate circuitry. The apparatus employs a turbine-driven filter wheel having a shaft position-encoding arrangement consisting of a hollow shaft portion which is internally illuminated. The hollow shaft portion has two sets of spaced apertures cyclically communicating with respective angularly spaced pairs of externally fixedly mounted phototransistors which are sequentially illuminated as the shaft portion rotates and which produce timing pulses which drive Schmitt triggers, which, in a typical embodiment, in turn produce pulses compatible with a logic circuit employed to decode the phototransistor signals into triggers for driving a 4-channel switched gain equalizer, a dark current clamp, and detector gates. Appropriate selection of the signals enables the instrument to function as a fluorometer or a spectrophotometer.
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Citations
17 Claims
- 1. In a multi-wavelength optical instrument of the type including a plurality of optical channels provided with respective gain equalizer means and signal detection means, a rotating filter member having a plurality of wavelength filters spaced around its axis to define said optical channels and provided with a supporting shaft having a hollow portion, means to illuminate said hollow shaft portion internally, respective signal-generating photosensitive means associated with the gain equalizer means and the signal detection means mounted externally adjacent said hollow shaft portion, said hollow shaft portion having means formed to illuminate said respective photosensitive means so as to generate respective cyclic sets of long and short pulses, and means to decode said pulses to derive respective cyclic gating pulses for said gain equalizer means and signal detection means.
- 4. In a multi-wave optical instrument of the type including a plurality of optical channels provided with respective gain equalizer means and respective measure signal detection means, a rotating filter member having a plurality of wavelength filters spaced around its axis to define said optical channels and provided with a supporting shaft having a hollow portion, means to illuminate said hollow shaft portion internally, first signal-generating photosensitive means mounted adjacent said hollow shaft portion, said hollow shaft portion having means formed to illuminate said first photosensitive means so as to generate cyclically relatively long pulses, second signal-generating photosensitive means mounted adjacent said hollow shaft portion, said hollow shaft portion having means formed to illuminate said second photosensitive means so as to generate cyclic sets of short pulses, and means to decode said long pulses and short pulses respectively to derive cyclic gating pulses for said gain equalizer means and cyclic gating pulses for said measure signal detection means.
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17. In a spectrofluorometer, a rotating filter member having a plurality of wavelength filters spaced around its axis, and respective excitation and fluorescent emission detection light path-defining means arranged to simultaneously transmit excitation light through one wavelength filter and fluorescence emission light through another wavelength filter, said light pathdefining means being at radial distances from the axis of rotation of said rotating filter member sufficiently different to prevent phosphorescence induced in said one filter from appearing in the fluorescence light path-defining means.
Specification