Abstract Apparatus for sorting objects from a stream of objects moving through a sorting zone in accordance with light reflected from the objects, has a light source to direct light into the sorting zone across the width of the stream and a single line array of photodiodes each having a photosensitive semiconductor junction adapted for operation in a photon flux storage mode. An electronic switch arrangement which scans the photodiodes by connecting the output of each photodiode singly in and in succession through the array to a common output. The signal at the common output represents a succession of values of summed or integrated reflected light which impinged on each photodiode during a predetermined interval. The predetermined interval being the time period between a particular photodiode being connected to the common output on successive switching scans or sweeps. A plurality of deflection devices, such as air nozzles, is in the sorting zone downstream of the photodiodes and extending across the width of the path in side by side relationship so that each deflection device defines a channel. Timing means is provided to (a) cycle the switching arrangement and (b) provide a timing signal relating the signal at the common output to respective channnels. A control circuit is connected to receive the timing signals and the signal at the common output to actuate the deflection devices to deflect objects which reflected light of predetermined characteristics.
Apparatus for sorting in accordance with light reflected from a stream of objects moving through a sorting zone along a predetermined path having a predetermined width, comprising a single line array comprising a plurality of photodiodes integrated into a single monolithic chip, each having a photosensitive semiconductor junction and adapted for operation in a photon flux storage mode, illuminating means to direct a source of light into said sorting zone across said predetermined width of said path, a lens system to focus an image of said stream extending across the illuminated width of said path onto said array, a plurality of deflection means in said sorting zone extending across the width of said path in side by side relationship, each deflection means defining a channel, the number of photodiodes being of an order of magnitude greater than the number of channels, switch means compressing a semiconductor switch for each photodiode for connecting to a common output each photodiode singly and in succession through said array to provide at said common output a first signal representing a succession of values of reflected light impinging on each photodiode during a predetermined interval, timing means comprising a shift register having a unit for each said semiconductor switch, a source of clock pulses to step said shift register through successive cycles to actuate said semiconductor switches in sequence, and a counter to count a predetermined number of clock pulses corresponding to a channel and to provide a timing signal for each count relating portions of said first signal to respective channels, and control means including a demultiplexer having a section for each channel, each section being connected for actuation of a respective deflection means, said sections being enabled in sequence by said timing signal from said counter, and a signal treating means for processing said first signal and applying the processed signal to said demultiplexer for actuating enabled deflection means for the deflection of objects which reflected light of predetermined characteristics.
Claim 2
Dependent Claim
327 words
Apparatus for sorting in accordance with light reflected from a stream of objects moving through a sorting zone along a predetermined path having a predetermined width, comprising a single line array comprising a plurality of photodiodes integrated into a single monolithic chip, each having a photosensitive semiconductor junction and adapted for operation in a photon flux storage mode, illuminating means to direct a source of light into said sorting zone across said predetermined width of said path, a lens system to focus an image of said stream extending across the illuminated width of said path onto said array, a plurality of deflection means in said sorting zone extending across the width of said path in side by side relationship, each deflection means defining a channel, the number of photodiodes being of an order of magnitude greater than the number of channels, switch means compressing a semiconductor switch for each photodiode for connecting to a common output each photodiode singly and in succession through said array to provide at said common output a first signal representing a succession of values of reflected light impinging on each photodiode during a predetermined interval, timing means comprising a shift register having a unit for each said semiconductor switch, a source of clock pulses to step said shift register through successive cycles to actuate said semiconductor switches in sequence, and a counter to count a predetermined number of clock pulses corresponding to a channel and to provide a timing signal for each count relating portions of said first signal to respective channels, and control means including a demultiplexer having a section for each channel, each section being connected for actuation of a respective deflection means, said sections being enabled in sequence by said timing signal from said counter, and a signal treating means for processing said first signal and applying the processed signal to said demultiplexer for actuating enabled deflection means for the deflection of objects which reflected light of predetermined characteristics.