Laser beam delivery path and target proximity sensor

• US 5,382,785 A
• Filed: 11/15/1993
• Issued: 01/17/1995
• Est. Priority Date: 05/04/1992
• Status: Expired due to Fees

• Current Assignee: Diolase Corporation
• Original Assignee: Diolase Corporation
• Inventors: Rink, John L.
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): Allen, Stephone B.
• Application Number:
  US08/153,310
• Time in Patent Office: 428 Days
• Field of Search: 250/561, 250/221, 250/205, 250/214 A, 606/12, 219/121.62
• US Class Current: 250/205
• CPC Class Codes: G01V 8/12 using one transmitter and one receiver
• CPC Class Codes: H03K 17/941 using an optical detector H03K17/968 takes precedence

Abstract

A laser diode operating system utilizes the photodiode mounted in the housing of the laser diode, and monitors the photodiode signal to check for a clear laser beam delivery path and a target proximate to the output of the beam path. Upon initial power-up of the system, a brief laser pulse is emitted, and laser light reflected retrograde in the delivery path is received by the photodiode. If the photodiode signal exceeds a first threshold level, due to occlusion of the delivery path, further operation of the system is prevented until the delivery path is cleared. During operator use, the photodiode signal is compared with a second threshold level, and operation is interrupted if the signal fails to exceed the second threshold level. During interruption of operation mode, the laser diode is pulsed briefly and reiteratively to ascertain if a target object is proximate to the laser diode output. If the reflected light level indicates that a target object is proximate, the system will restore continuous operating mode while continuing to monitor the photodiode current.

Claims

1. An operating system for a laser diode device, including;

a laser diode for emitting a laser beam along a beam delivery path;

photosensor means disposed proximate to said laser diode to receive laser diode light reflected retrograde in said beam delivery path and generate a photodiode signal;

sampling pulse means for driving said laser diode to emit a brief sampling pulse upon power-up of said operating system;

means for comparing said photodiode signal during said brief sampling pulse to a predetermined beam path threshold level; and

,

means for warning of an occluded beam delivery path if said photodiode signal exceeds said predetermined beam path threshold level.

2. The operating system of claim 1, further including means for comparing said photodiode signal during said brief sampling pulse to a plurality of nominal value ranges, each range corresponding to a differing beam delivery path configuration.

3. The operating system of claim 2, further including a plurality of predetermined beam path threshold levels, each of said predetermined beam path threshold levels associated with one of said nominal value ranges, and means for selecting a beam path threshold level associated with a nominal value range of said photodiode signal.

4. The operating system of claim 1, further including operating control means for actuating said laser diode for treatment purposes, and means for comparing said photodiode signal to a predetermined target threshold level during actuation of said laser diode for treatment purposes to determine if a target is proximate to the output of said beam delivery path.

5. The operating system of claim 4, further including means for interrupting operation of said laser diode if said photodiode signal fails to exceed said target threshold level.

6. The operating system of claim 5, further including means for reiteratively actuating said laser diode to emit brief sampling pulses when operation of said laser diode is interrupted, and means for comparing said photodiode signal to said target threshold level during said brief sampling pulses.

7. A method for operating a laser system employing a laser diode device having a monitor photodiode, including the steps of:

actuating said laser diode to emit a brief sampling pulse upon power-up of said laser system and prior to operator use of said laser system to check the beam delivery path of said laser diode;

comparing the output signal of said monitor photodiode to a beam path threshold level; and

blocking further operation of said laser diode when said output signal of said monitor photodiode exceeds said beam path threshold level, indicative of at least partial occlusion in said beam delivery path of said laser diode.

8. A method for operating a laser system employing a laser diode device having a monitor photodiode, including the steps of:

actuating said laser diode to emit a brief sampling pule upon power-up of said laser system and prior to operator use of said laser system;

comparing the output signal of said monitor photodiode to a first threshold level;

blocking further operation of said laser system when said output signal of said monitor photodiode exceeds said first threshold level, indicative of at least partial occlusion in the beam delivery path of said laser diode;

comparing said output signal of said monitor photodiode to a second threshold level during operator use of said laser system to determine if a target is proximate to the output of the laser beam delivery path; and

interrupting operation of said laser diode when said output signal of said monitor photodiode fails to exceed said second threshold level.

9. The method of claim 8, further including the step of operating said laser diode to emit brief sampling pulses after interruption of operation of said laser diode, and resuming continuous operator use of said laser diode when said output signal of said monitor photodiode exceeds said second threshold level during any of said brief sampling pulses.