Laser archery distance device

• US 4,753,528 A
• Filed: 08/30/1985
• Issued: 06/28/1988
• Est. Priority Date: 12/13/1983
• Status: Expired due to Fees

• Current Assignee: Quantime Incorporated (Time by Ping, Inc.)
• Original Assignee: Quantime Incorporated (Time by Ping, Inc.)
• Inventors: Plummer, Paul L., Hines, Robin H., Glasscock, Michael R., Johnson, D. Bruce
• Primary Examiner(s): Paschall, M. H.
• Application Number:
  US06/770,970
• Time in Patent Office: 1,033 Days
• Field of Search: 33/265, 356/1, 356/3, 356/4, 356/5, 356/400
• US Class Current: 356/3.04
• CPC Class Codes: G01C 3/10 using a parallactic triangle with variable angles and a base of fixed length in the observation station, e.g. in the instrument

Abstract

A method and apparatus for determining distance from a bow to a target at which the bow is aimed in which a beam of collimated light from a laser is directed to the target and reflected to a linear photosensitive element mounted on the bow. The element and laser are positioned on the bow so that the linear position of the incident reflected beam varies with the target distance and the element produces an output indicating the position. A circuit receives that output and produces a display of the target distance.

Claims

1. Apparatus for determining distance from a bow to a target comprising:

means for producing a beam of collimated light;

linear-shaped photosensitive means for producing an output signal indicating the linear position of an incident beam of reflected light;

means for mounting said light producing means and said photosensitive means adjacent to each other on a bow so that said beam is reflected from a target to said photosensitive means when the bow is aimed at said target and the linear position of the incident beam on the photosensitive means varies with the distance to said target; and

circuit means connected to said photosensitive means for receiving said output signal and producing an output indicating the distance to said target said circuit means including;

(a) means for producing a train of clock pulses;

(b) an automatic gain control amplifier;

(c) switching means controlled by said clock pulses for alternatively applying first and second current signals to said automatic gain control amplifier;

(d) a single hold circuit for receiving the output of said automatic gain control amplifier and controlled by said clock pulses to alternatively produce an output indicating the respective amplitudes of said first and second current signals;

(e) a summing circuit for receiving said hold circuit output and controlling said automatic gain control circuit in accordance with said first current signal;

(f) means for receiving said hold circuit output and producing an output indicative of said second current signal and therefore the position of the incident beam; and

(g) means for displaying said output indicative of the position of the incident beam.

2. Apparatus as in claim 1 wherein said photosensitive means is a linear photodiode producing first and second current signals the amplitudes of which vary with the position of the incident reflected beam;

and said circuit means includes means for producing an output which varies with the ratio of the difference of the amplitudes of said first and second current signals to the sum of the amplitudes of said first and second current signals.

3. Apparatus as in claim 1 wherein said beam producing means is a solid state laser.

4. An apparatus for determining distance from a bow to a target at which an arrow is aimed comprising:

means for directing a beam of collimated light to said target;

means for detecting the linear position of the reflected beam from said target on a photosensitive element;

means for mounting said beam directing means and detecting means on a bow; and

circuit means for determining the distance to said target from said linear position, said circuit means including;

(a) means for producing a train of clock pulses;

(b) an automatic gain control amplifier;

(c) switching means controlled by said clock pulses for alternatively applying first and second current signals to said automatic gain control amplifier;

(d) a single hold circuit for receiving the output of said automatic gain control amplifier and controlled by said clock pulses to alternatively produce an output indicating the respective amplitudes of said first and second current signals;

(e) a summing circuit for receiving said hold circuit output and controlling said gain control circuit in accordance with said first current signal;

(f) means for receiving said hold circuit output and producing an output indicative of said second current signal and therefore the position of the incident beam; and

(g) means for displaying said output indicative of the position of the incident beam.

5. A circuit for producing an output signal indicating the position of a beam of radiation incident on a linear photodiode producing first and second current signals with the means of maintaining the first current constant so that the amplitude of the second current varies directly and linearly with the distance to the incident radiation comprising:

means for producing a train of clock pulses;

an automatic gain control amplifier;

switching means controlled by said clock pulses for alternatively applying first and second current signals to said gain control amplifier;

a single hold circuit for receiving the output of said gain control amplifier and controlled by said clock pulses to alternately produce an output indicating the respective amplitudes of said first and second current signals;

a control citcuit for receiving said hold circuit output and controlling said gain control circuit in accordance with the first current amplitude;

a position circuit for receiving said hold circuit output and producing an output indicating the amplitude of said second current signal and therefore the position of the incident beam; and

means for displaying said position output indicative of the position of the incident beam.

6. A circuit as in claim 5 further including a laser driver circuit by said clock pulses.

7. A circuit as in claim 5, wherein said display means includes a digital display and an analog-to-digital converter connected to said digital display and to said position circuit.

8. A circuit as in claim 5 further including first and second peaking detecting means for each applying an output to said control circuit and to said position circuit and second switching means controlled by said clock pulse for alternately applying the output of said hold circuit to said peak detecting means.