Position-to-digital encoder

• US 4,212,000 A
• Filed: 08/21/1978
• Issued: 07/08/1980
• Est. Priority Date: 08/20/1977
• Status: Expired due to Term

• Current Assignee: Minolta Camera Kabushiki Kaisha
• Original Assignee: Minolta Camera Kabushiki Kaisha
• Inventors: Yamada, Seiji
• Primary Examiner(s): Miller, Charles D.
• Application Number:
  US05/935,390
• Time in Patent Office: 687 Days
• Field of Search: 200/11 R, 200/11 DA, 200/11 G, 200/11 J, 340/347 P, 340/347 DD, 354/23 D, 354/24
• US Class Current: 396/258
• CPC Class Codes: H03M 1/287 using gradually changing slit width or pitch within one track; using plural tracks having slightly different pitches, e.g. of the Vernier or nonius type

Abstract

A position-to-digital encoder for generating digital signals in the form of binary code in accordance with the relative positions between a pair of brush contacts and a series of contacts arranged in order. The latter contacts are disposed in a row along the path of movement of the brush contacts, with equal pitches and gaps between adjacent contacts. The brush contacts are spaced from each other along their path of movement with such a distance that two brush contacts are in contact with a single one of the series of contacts or with an adjacent two of the series of contacts, respectively. One line extends from each contact to a decoder which generates signals in accordance with which contact or contacts of the contact series is engaged by the brush contacts. The decoder generates different signals in accordance with whether a single or double contact is engaged by the brush contacts so that (2n-1) different signals may be obtained as a function of the relative position between the brush, contacts and the series of contacts, where n is the number of the latter contacts.

Claims

1. A digital code signal generating device comprising:

at least one set of a plurality of conducting elements each arranged in a row with each of said conducting elements having the same pitch and the same length with respect to the direction of the row, and said conducting elements being spaced to have the same gap between adjacent conducting elements;

at least one pair of brush contacts slidable over said at least one set of conducting elements along the direction of said row, and being spaced from one another in the direction of the row such that said at least one pair of contacts are either both on a single conducting element or respectively on two adjacent conducting elements;

supply means for providing an electrical signal to said at least one pair of brush contacts; and

a decoder interconnected with each one of said conducting elements for generating two sets of different binary coded outputs in accordance with whether said at least one pair of brush contacts are contacting one or two of said conducting elements.

2. A digital code signal generating device as in claim 1, wherein said supply means includes a third brush contact electrically connected with said pair of brush contacts and a conducting strip disposed adjacent said at least one set of conducting elements, said third brush contact being in contact with said conducting strip;

and an electrical power source connected with said conducting strip to provide said electrical signal.

3. A digital code signal generating device as in claim 1 wherein said at least one pair of brush contacts is connected respectively through at least one diode to a common point through which said electric signal is applied.

4. A digital code signal generating device as in claim 1 further comprising a pair of conducting strips electrically separated from each other and disposed adjacent said at least one set of conducting elements, and wherein said one of said pair of brush contacts bridges said set of conducting elements and said one of said conducting strips and the other of said pair of brush contacts bridges said set of conducting elements and the other of said conducting strips, and each one of said pair of brush contacts is connected respectively through a diode to a common point through which said electrical signal is applied.

5. A digital code signal generating device as in claim 4 further comprising a third pair of brush contacts mounted to travel on said conducting elements, and said supply means further includes an additional pair of diodes connected with said third pair of brush contacts to provide a second electrical signal thereto.

6. A digital code signal generating device as in claim 1 wherein said decoder includes a first set of gate members for generating a first signal with said at least one pair of brush contacts contact one of said conducting elements, and a second set of gate members for generating a second signal with said at least one pair of brush contacts contact two of said adjacent conducting elements.

7. A digital code signal generating device as in claim 6 wherein said decoder further includes a diode matrix circuit connected to said first and second set of gate members for generating binary coded signals.

8. A camera control mechanism using the digital code signal generating device as defined in claim 1, the camera having a diaphragm presetting ring for setting the diaphragm aperture, and further comprising means interconnecting said at least one pair of brush contacts and said diaphragm presetting ring to generate input signals to said decoder representative of the diaphragm aperture setting;

means for generating an optimum diaphragm aperture setting signal;

means for comparing the outputs of said decoder with said optimum diaphragm aperture setting signal and providing a control signal output when said decoder output and said aperture setting signal are substantially the same; and

means for stopping the movement of said diaphragm presetting ring in response to said control signal output.

9. A camera control mechanism as in claim 8 wherein said interconnecting means includes a rotatable disc and said at least one pair of brush contacts being mounted in insulated relationship thereto, and linkage means connected to said disc and said diaphragm presetting means;

said means for stopping including a gear meshing with said rotatable disc, ratchet wheel means meshing with said gear, and electromagnetically actuated claw means energized to engage said ratchet wheel in accordance with said control signal.

10. A digital code signal generating device as in claim 1 wherein said decoder includes means for generating a series of signals as said two sets of binary coded outputs, said series of signals changing sequentially with the advancement of said at least one pair of brush contacts, wherein a signal generated with said at least one pair of brush contacts being respectively on two adjacent conducting elements represents a value between values represented by signals generated with said brush contacts being both on either of the adjacent conducting elements.

11. A digital code signal generating device as in claim 1 wherein 2n-1 different signals are generated by said brush contacts where n is the number of conducting elements.