Multiple function spectrophotometer having an automatically stabilized chopper disc

Claim 2

A spectrophotometer comprising two monochromators adapted to provide two respective monochromatic beams of radiation, a photosensitive device, means to direct said two beams toward said photosensitive device substantially along a first optical path, time-sharing chopper disc means in said first optical path and having means to alternately direct said two monochromatic beams toward said photosensitive device along said first optical path, whereby said monochromatic beams can alternately pass through a transparent container placed in said first optical path between said chopper disc means and said photosensitive device to provide a dual wavelength mode of operation, and means to at times direct a portion of one of said monochromatic beams reaching said chopper disc means along a second optical path toward said photosenSitive device, whereby said portion can pass through a transparent reference container placed in said second optical path, to provide a split beam mode of operation, and wherein said chopper disc means has a driving motor, said chopper disc means including a notched disc defining spaced chopper segments, neans to detect variations in the speed of movement of said spaced chopper segments, and means to adjust the speed of said motor in accordance with such variations.

Claim 3

A spectrophotometer comprising two monochromators adapted to provide two respective monochromatic beams of radiation, a photosensitive device, means to direct said two beams toward said photosensitive device substantially along a first optical path, time-sharing chopper disc means in said first optical path and having means to alternately direct said two monochromatic beams toward said photosensitive device along said first optical path, whereby said monochromatic beams can alternately pass through a transparent sample container placed in said first optical path between said chopper disc means and said photosensitive device to provide a dual wavelength mode of operation, and means to at times direct a portion of one of said monochromatic beams reaching said chopper disc means along a second optical path toward said photosensitive device, whereby said portion can pass through a transparent reference container placed in said second optical path, to provide a split beam mode of operation, and wherein at least one of the monochromators is provided with means to vary the wavelength of its output monochromatic beam, said first-named directing means including an axially movable focussing lens element, and means coupling said lens element to said wavelength varying means to move the lens element so as to substantially compensate for chromatic aberration.

Claim 4

A spectrophotometer comprising two monochromators adapted to provide two respective monochromatic beams of radiation, a photosensitive device, means to direct said two beams toward said photosensitive device substantially along a first optical path, time-sharing chopper disc means in said first optical path and having means to alternately direct said two monochromatic beams toward said photosensitive device along said first optical path, whereby said monochromatic beams can alternately pass through a transparent sample container placed in said first optical path between said chopper disc means and said photosensitive device to provide a dual wavelength mode of operation, and means to at times direct a portion of one of said monochromatic beams reaching said chopper disc means along a second optical path toward said photosensitive device, whereby said portion can pass through a transparent reference container placed in said second optical path, to provide a split beam mode of operation, and wherein at least one of the monochromators is provided with means to vary the wavelength of its output monochromatic beam, said first-named directing means including an axially movable focussing lens element, and means coupling said lens element to said wavelength varying means to move the lens element so as to substantially compensate for chromatic aberration.

Claim 5

A spectrophotometer comprising two monochromators adapted to provide two respective monochromatic beams of radiation, a photosensitive device, means to direct said two beams toward said photosensitive device substantially along a first optical path, time-sharing chopper disc means in said first optical path and having means to alternately direct said two monochromatic beams toward said photosensitive device along said first optical path, whereby said monochromatic beams can alternately pass through a transparent sample container placed in said first optical path between said chopper disc means and said photosensitive device to provide a dual wavelength mode of operation, and means to at times direct a portion of one of said monochromatic beams reaching said chopper disc means along a second optical path toward said photosensitive device, whereby said portion can pass through a transparent reference container placed in said second optical path to provide a split beam mode of operation, and wherein said chopper disc means has a driving motor, said chopper disc means including a notched disc defining chopper segments, means spaced angularly relative to the axis of the chopper disc to count said segments as they move therepast, means to add together the counts obtained by said spaced meaNs, and means to adjust the speed of said motor in accordance with variations in the total of the counts.

Claim 6

A spectrophotometer comprising two monochromators adapted to provide two respective monochromatic beams of radiation, a photosensitive device, means to direct said two beams toward said photosensitive device substantially along a first optical path, time-sharing chopper disc means in said first optical path and having means to alternately direct said two monochromatic beams toward said photosensitive device along said first optical path, whereby said monochromatic beams can alternately pass through a transparent sample container placed in said first optical path between said chopper disc means and said photosensitive device to provide a dual wavelength mode of operation, and means to at times direct a portion of one of said monochromatic beams reaching said chopper disc means along a second optical path toward said photosensitive device, whereby said portion can pass through a transparent reference container placed in said second optical path to provide a split beam mode of operation, and wherein said chopper disc means has a driving motor, said chopper disc means including a notched disc defining chopper segments, means spaced angularly relative to the axis of the chopper disc to count said segments as they move therepast, means to add together the counts obtained by said spaced meaNs, and means to adjust the speed of said motor in accordance with variations in the total of the counts.

Claim 7

The spectrophotometer of claim 3, and wherein said photosensitive device is of a type generating electrical output pulse signals, respective integrating circuits connected to the output of said photosensitive device and being of a type generating steady d.c. voltages in accordance with the amplitudes of said pulse signals, and means to gate said integrating circuits synchronously with the count of said moving segments.

Claim 8

The spectrophotometer of claim 4, and means to compare said steady d.c. voltages.

Claim 9

The spectrophotometer of claim 2, and wherein said one of the monochromators comprises a reflectance grating provided with rotary supporting shaft means, and wherein said coupling means comprises a lever member secured on said shaft means, rack and pinion means drivingly connected to said movable lens element, and interengaging cam and follower means drivingly coupling said rack and pinion means to said lever member.

Claim 10

The spectrophotometer of claim 6, and wherein said cam and follower means comprises a projection on said lever member and a cam element operatively connected to said rack and pinion means and engaging said projection.

Claim 11

The spectrophotometer of claim 7, and means biasing said cam element into continuous engagement with said projection.

Claim 12

The spectrophotometer of claim 8, and means to operate said rotary shaft means so as to angularly adjust said reflectance grating, said operating means comprising a rotary screw member and a travelling nut member threadedly engaged on said rotary screw member and drivingly engaging said lever member.

Claim 13

The spectrophotometer of claim 9, and wherein said lever member is provided with a second projection and said travelling nut member is located so that said biasing means urges said second projection toward continuous engagement with said travelling nut member.

Claim 14

The spectrophotometer of claim 3, and wherein said chopper disc segments have reflective surfaces and wherein said counting and adding means comprises spaced fiber optic systems located to receive light reflections from said reflective surfaces and having respective photosensitive transducers generating pulse signals responsive to said light reflections, and means to derive a voltage representing the sum of said pulse signals, and wherein said speed-adjusting means comprises means to compare said sum with a reference voltage and derive a difference signal, and means to energize said motor responsive to said difference signal.

Claim 15

The spectrophotometer of claim 11, and wherein said photosensitive device is of a type generating electrical output pulse signals in accordance with the intensity of the beams impinging thereon, respective integrating circuits connected to the output of said photosensitive device, said integrating circuits being of a type generating steady d.c. voltages in accordance with the amplitudes of said last-named pulse signals, and means to gate said integrating circuits synchronously with said light reflections.

Claim 16

The spectrophotometer of claim 12, and a differential amplifier, circuit means connecting the steady d.c. voltage outputs of said integrating circuits to the inputs of said differential amplifier, and indicating means connected to the output of said differential amplifier.

Claim 17

A spectrophotometer comprising monochromator means adapted to provide a beam of monochromatic radiation, a photosensitive device, means to direct the monochromatic beam along an optical path leading to said photosensitive device, time-sharing chopper disc means in said optical path, said chopper disc means having a driving motor, said chopper disc means including a notched disc defining spaced chopper segments, means spaced angularly relative to the axis of the chopper disc to count said segments as they move therepast, means to add together the counts obtained by said spaced means, and means to adjust the speed oF said motor in accordance with variations in the total of said counts.

Claim 18

A spectrophotometer comprising monochromator means adapted to provide a beam of monochromatic radiation, a photosensitive device, means to direct the monochromatic beam along an optical path leading to said photosensitive device, time-sharing chopper disc means in said optical path, said chopper disc means having a driving motor, said chopper disc means including a notched disc defining spaced chopper segments, means spaced angularly relative to the axis of the chopper disc to count said segments as they move therepast, means to add together the counts obtained by said spaced means, and means to adjust the speed oF said motor in accordance with variations in the total of said counts.

Claim 19

The spectrophotometer of claim 14, and wherein said spaced counting means comprises spaced fiber optic systems located to sequentially receive light reflections from said segments and having respective photosensitive transducers generating pulse signals responsive to said light reflections, said adding means comprising means to derive a voltage representing the sum of said pulse signals, and said speed-adjusting means comprising means to compare said sum voltage with a reference voltage and derive a difference signal and means to energize said motor responsive to said difference signal.

Claim 20

The spectrophotometer of claim 14, and wherein said photosensitive device is of a type generating electrical output pulse signals in accordance with the intensity of the beams impinging thereon, respective integrating circuits connected to the output of said photosensitive device, said integrating circuits being of a type generating steady d.c. voltages in accordance with the amplitudes of said last-named pulse signals, and means to gate said integrating circuits synchronously with said counts.

Claim 21

The spectrophotometer of claim 15, and wherein said photosensitive device is of a type generating electrical output pulse signals in accordance with the intensity of the beams impinging thereon, respective integrating circuits connected to the output of said photosensitive device, said integrating circuits being of a type generating steady d.c. voltages in accordance with the amplitudes of said last-named pulse signals, and means to gate said integrating circuits synchronously with said light reflections.

Claim 22

The spectrophotometer of claim 14, and wherein said monochromator means is provided with means to vary the wavelength of its output monochromatic beam, said directing means including an axially movable focussing lens element, and means coupling said lens element to said wavelength-varying means to move the lens element so as to substantially compensate for chromatic aberration.

Claim 23

A spectrophotometer comprising monochromator means adapted to provide an output monochromatic beam of radiation and provided with means to vary the wavelength of its output monochromatic beam, a photosensitive device, means to direct the output monochromatic beam toward said photosensitive device along an optical path leading to said photosensitive device, said directing means including an axially movable lens element, and means coupling said lens element to said wavelength-varying means to move the lens element so as to substantially compensate for chromatic aberration.

Claim 24

A spectrophotometer comprising monochromator means adapted to provide an output monochromatic beam of radiation and provided with means to vary the wavelength of its output monochromatic beam, a photosensitive device, means to direct the output monochromatic beam toward said photosensitive device along an optical path leading to said photosensitive device, said directing means including an axially movable lens element, and means coupling said lens element to said wavelength-varying means to move the lens element so as to substantially compensate for chromatic aberration.