US3710375A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical encoder
Assignee: DH Baldwin Co
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Filing: 1971-10-20
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Granted: 1973-01-09
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Expires: 1991-10-20
Abstract
Abstract An optical encoder is disclosed utilizing a V-scan method of read-out which provides the output for each track of a code disc and the complementary output of that track. Each track, except the least significant track of the code disc, is provided with two pair of photocells, one to produce the leading and complementary leading output and the other to produce the lagging and complementary lagging output. A novel electrical circuit is utilized by the encoder to reduce the number of components required in obtaining a parallel output and parallel complementary output, the complementary output being obtained at the code disc.
Inventors
- 👤 J Brean
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:14
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/22; H03M1/24; H03M1/26
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
605 words
A device for digitally encoding the position of a movable element comprising, in combination: a code member adapted to be mechanically coupled to the movable element to be encoded and to move in response to movement of the element to be encoded, said code member defining a plurality of tracks consisting of alternate transparent and opaque sectors of equal length, each track defining a path parallel to the direction of movement of the code member, the transparent and opaque sectors of one of said tracks being one half the length along the path of the transparent and opaque sectors of a second track, a light source disposed on one side of the code member for illuminating at least a portion of the first and second tracks of the code member, a first photocell disposed on the side of the code member opposite the light source confronting the illuminated portion of said one track of the code member, said first photocell being disposed on a first fixed axis relative to the code member normal to the path of movement of the said one track, a first pair and a second pair of photocells mounted in fixed positions relative to the code member on the side of the code member opposite the light source confronting the illuminated portion of the second track of the code member, the photocells of the first pair being disposed on a first pair of axes normal to the path of the second track and spaced by a distance between one-half the length and one and onehalf times the length of the sectors of the second track, the first axis of said first pair confronting a portion of a sector of the second track higher in count than the portion of the second track confronted by the first axis, the photocells of the second pair being disposed on a second pair of axes normal to the path of the second track and spaced by a distance between onehalf the length and one and one-halF times the length of the sectors of the second track, the first axis of said second pair confronting a portion of a sector of the second track lower in count than the portion of the second track confronted by the first axis, and means electrically connected to the photocells for electrically reading the output of the photocells, said means having a first output terminal, a second output terminal and a third output terminal upon each of which a first electrical output is produced to indicate an illuminated photocell and a second electrical output is produced to indicate a photocell in the dark, the electrical output of the first photocell exciting the first output terminal, the electrical output of the photocell of each pair confronting the first axes thereof exciting the second output terminal, and the electrical output of the photocell of each pair confronting the second axes thereof exciting the third output terminal, and a selection device electrically connected between the first photocell and the first and second pairs of photocells, said selection device being responsive to an electrical output on the first output terminal of the first type to select the responses of the first pair of photocells and responsive to an output on the first terminal of the second type to select the second pair of photocells for the second and third output terminals, whereby the electrical output on the first and second output terminals represents the position of the code member in binary numbers and the electrical signal on the third output terminal represents the binary complement of the electrical signal on the second output terminal.
Claim 2
Independent Claim
605 words
A device for digitally encoding the position of a movable element comprising, in combination: a code member adapted to be mechanically coupled to the movable element to be encoded and to move in response to movement of the element to be encoded, said code member defining a plurality of tracks consisting of alternate transparent and opaque sectors of equal length, each track defining a path parallel to the direction of movement of the code member, the transparent and opaque sectors of one of said tracks being one half the length along the path of the transparent and opaque sectors of a second track, a light source disposed on one side of the code member for illuminating at least a portion of the first and second tracks of the code member, a first photocell disposed on the side of the code member opposite the light source confronting the illuminated portion of said one track of the code member, said first photocell being disposed on a first fixed axis relative to the code member normal to the path of movement of the said one track, a first pair and a second pair of photocells mounted in fixed positions relative to the code member on the side of the code member opposite the light source confronting the illuminated portion of the second track of the code member, the photocells of the first pair being disposed on a first pair of axes normal to the path of the second track and spaced by a distance between one-half the length and one and onehalf times the length of the sectors of the second track, the first axis of said first pair confronting a portion of a sector of the second track higher in count than the portion of the second track confronted by the first axis, the photocells of the second pair being disposed on a second pair of axes normal to the path of the second track and spaced by a distance between onehalf the length and one and one-halF times the length of the sectors of the second track, the first axis of said second pair confronting a portion of a sector of the second track lower in count than the portion of the second track confronted by the first axis, and means electrically connected to the photocells for electrically reading the output of the photocells, said means having a first output terminal, a second output terminal and a third output terminal upon each of which a first electrical output is produced to indicate an illuminated photocell and a second electrical output is produced to indicate a photocell in the dark, the electrical output of the first photocell exciting the first output terminal, the electrical output of the photocell of each pair confronting the first axes thereof exciting the second output terminal, and the electrical output of the photocell of each pair confronting the second axes thereof exciting the third output terminal, and a selection device electrically connected between the first photocell and the first and second pairs of photocells, said selection device being responsive to an electrical output on the first output terminal of the first type to select the responses of the first pair of photocells and responsive to an output on the first terminal of the second type to select the second pair of photocells for the second and third output terminals, whereby the electrical output on the first and second output terminals represents the position of the code member in binary numbers and the electrical signal on the third output terminal represents the binary complement of the electrical signal on the second output terminal.
Claim 3
Dependent Claim
331 words
A device for digitally encoding the position of a movable element comprising the combination of claim 1 wherein the code member has a third track with transparent and opaque sectors with lengths four times that of the first track, a portion of said third track being illuminated by the light source, and said device having a third pair and a fourth pair of photocells mounted in fixed positions relative to the code member on the side of the code member opposite the light source confronting the illuminated portion of the third track of the code member, the photocells of the third pair and fourth pair being disposed on a third pair and fourth pair of axes normal to the path of the third track and spaced by a distance approximately equal to the length of the sectors of the third track, respectively, the one axis of said third pair confronting a portion of a sector of the third track higher in count than the portion of the sector of the third track confronting the first axis, the one axis of said fourth pair confronting a portion of one of the sectors of the third track lower in count than the portion of the sector of the third track confronting the first axis, and the means for electrically reading the output of the cells electrically connected to the second and third output terminals including a fourth and a fifth output terminal, the photocell of the third and fourth pair confronting the first axes thereof electrically exciting the fourth output terminal, the photocell of the third and fourth pair confronting the second axes thereof electrically exciting the fifth output terminal, said selection device being responsive to an electrical output on the second output terminal of the first type to select the responses of the third pair, and said selection device being responsive to an electrical output on the third output terminal of the first type to select the responses of the fourth pair.
Claim 4
Dependent Claim
32 words
A device for digitally encoding the position of a movable element comprising the combination of claim 1 wherein the photocells comprise two spaced electrodes and a mass of photoresistive material disposed therebetween.
Claim 5
Dependent Claim
192 words
A device for digitally encoding the position of a movable element comprising the combination of claim 3 wherein the selection means comprises a source of potential and a first resistor connected in a series circuit with the first photocell; a first means for impressing a potential on the first pair of photocells responsive to a potential on the first resistor including a first series circuit comprising the first photocell of the first pair and a second resistor, and a second series circuit comprising the second photocell of the first pair, and a third resistor; a second means for impressing a potential on the second pair of photocells including an inverter and a third and fourth series circuit, said second means including a third series circuit comprising the first photocell of the second pair of photocells and the second resistor, and a fourth series circuit comprising the second photocell of the second pair of photocells and the third resistor; the first output terminal being electrically connected to the first resistor, the second output terminal being electrically connected to the second resistor, and the third output terminal being electrically connected to the third resistor.
Claim 6
Dependent Claim
36 words
A device for digitally encoding the position of a movable element comprising the combination of claim 4 in combination with a diode connected in series with each of the first, second, third and fourth series circuits.
Claim 7
Dependent Claim
22 words
A device for digitally encoding the position of a movable element comprising the combination of claim 1 wherein the photocells are photovoltaic.
Claim 8
Dependent Claim
88 words
A device for digitally encoding the position of a movable element comprising the combination of claim 6 wherein the selection means comprises a bias source connected to the emitter of each of the photocells, a plurality of amplifiers, the input of a separate amplifier being connected to the base of each of the photocells, the input of each of said amplifiers being at a potential to back bias the photocell connected thereto when said photocell is in the dark, but insufficient to back bias said photocell when illuminated.
Claim 9
Dependent Claim
65 words
A device for digitally encoding the position of a movable element comprising the combination of claim 7 wherein the selection means comprises a switching device controlled by the output of the first photocell and electrically connected to the amplifiers connected to the photocells of the first pair to activate said amplifiers only in response to an output from the first photocell of the first type.
Claim 10
Dependent Claim
74 words
A device for digitally encoding the position of a movable element comprising the combination of claim 8 wherein the selection means includes a second switching device coupled to the first photocell and being controlled by the first photocell, said second switching device being electrically connected to the amplifiers connected to the photocells of the second pair to actuate said amplifiers only in response to an output from the first photocell of the second type.
References Cited (Backward Citations)
US3618074A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |