Lens inspection system

• US 5,805,276 A
• Filed: 11/27/1996
• Issued: 09/08/1998
• Est. Priority Date: 12/21/1992
• Status: Expired due to Term

• Current Assignee: Johnson & Johnson Vision Products, Inc.
• Original Assignee: Johnson & Johnson Vision Products, Inc.
• Inventors: Wilder, Joseph, Davis, Thomas G., Dreyfuss, David
• Primary Examiner(s): Pham, Hoa Q.
• Application Number:
  US08/757,334
• Time in Patent Office: 650 Days
• Field of Search: 356/124-127, 356/237, 356/239, 356/240, 356/430, 356/244, 356/246, 264/2.6, 250/572, 250/233 B, 250/562, 358/101, 358/106, 358/107, 382/8, 382/65
• US Class Current: 356/124
• CPC Class Codes: G01M 11/0207 Details of measuring devices
• CPC Class Codes: G01M 11/0214 Details of devices holding the object to be tested
• CPC Class Codes: G01M 11/0235 by measuring multiple properties of lenses, automatic lens meters
• CPC Class Codes: G01M 11/0278 Detecting defects of the object to be tested, e.g. scratches or dust investigating the presence of flaws or contamination on materials by optical means G01N21/88

Abstract

A system for inspecting ophthalmic lenses and including transport, illumination, imaging and image processing subsystems. The transport system moves a multitude of ophthalmic lenses along a predetermined path to move each of those lenses, one at a time, into a lens inspection position, and the illumination subsystem generates a series of light pulses and directs a respective one light pulse through each ophthalmic lens. The imaging subsystem generates a set of signals representing selected portions of the light pulses transmitted through the ophthalmic lenses, and the image processing subsystem receives those signals from the imaging subsystem and processes those signals according to a predetermined program to identify at least one condition of each of the lenses.

Claims

1. An automatic lens inspection system, said automatic system comprising:

a transport subsystem to continuously move a plurality of ophthalmic lenses along a predetermined path to move each of the plurality of lenses, one at a time, into a lens inspection position, the transport subsystem including a lens carrier to hold each of the lenses substantially level in a fluid solution as the lens moves along said path and into said lens inspection position;

an illumination subsystem to generate a series of light pulses and to direct a respective one light pulse through each ophthalmic lens when the lens in the fluid solution is in the lens inspection position;

an imaging subsystem, said imaging subsystem having a pixel array to generate a set of signals representing selected portions of the light pulses transmitted through the ophthalmic lenses;

an opaque stop positioned between the pixel array and the lens inspection position;

an imaging lens positioned between the opaque stop and the lens inspection position to focus onto the stop a first portion of the light transmitted through the lens inspection position, and to focus on the pixel array a second portion of the light transmitted through the lens inspection position; and

an image processing subsystem to receive said signals from the imaging subsystem and to process said signals according to a predetermined program to identify at least one condition of each said lenses.

2. A lens inspection system according to claim 1, wherein the transport subsystem further includes

a support assembly supporting the lens carrier and adapted to move the lens carrier to move each of the lenses therein, one at a time, into the lens inspection position.

3. A lens inspection system according to claim 2, wherein:

the support assembly includes

i) a translation table including a base, a first frame supported by the base for movement in a first direction, and a second frame supported by the first frame for movement in a second direction, perpendicular to said first direction, and

ii) means to move the first frame in said first direction, and to move the second frame in said second direction; and

the lens carrier is supported by the second frame for movement therewith.

4. A lens inspection system according to claim 1, wherein the illumination subsystem includes:

a flash lamp to generate the light pulses;

a lamp controller to actuate the flash lamp at selected times; and

means to direct the light pulses from the flash lamp, along a predetermined path, and through the ophthalmic lenses moving through the lens inspection position.

5. A lens inspection system according to claim 4, wherein the illumination subsystem further includes an adjustable diaphragm located on said predetermined path to adjust the size of a cross-sectional area of the light pulses.

6. A lens inspection system according to claim 1, wherein:

the illumination subsystem directs the light pulses through the lens inspection position and onto the imaging subsystem along a given axis; and

the pixel array, the opaque stop and the imaging lens are positioned on said given axis.

7. A lens inspection system according to claim 1, further comprising a control subsystem to actuate the illumination subsystem to generate a respective one of the light pulses each time one of the ophthalmic lenses moves through the lens inspection position.

9. A lens inspection system according to claim 1, wherein:

the transport subsystem includes means to generate a trigger signal each time one of the ophthalmic lenses moves through the lens inspection position;

the illumination subsystem includes

i) a flash lamp to generate the light pulses, and

ii) a lamp controller to actuate the flash lamp at selected times;

the imaging subsystem includes

i) a housing, and

ii) a pixel array disposed in the housing to generate said set of signals,

the housing including a shutter having a closed position, and an open position to expose the pixel array to the light pulses directed through the ophthalmic lenses; and

wherein the lens inspection system further includes a control subsystem to receive the trigger signal from the transport subsystem and to transmit the trigger signal (i) to the lamp controller to actuate the flash lamp to generate one of the light pulses, and (ii) to said shutter to move the shutter to the open position to expose the pixel array to said one of the light pulses.

10. A lens inspection system according to claim 1, wherein:

the imaging subsystem generates a respective one set of signals representing selected portions of the light pulse transmitted through each of the ophthalmic lenses; and

the image processing sub-system processes each of said sets of signals to determine if any one of a plurality of predetermined conditions are present in each of the ophthalmic lenses; and

if any one of said predetermined conditions is found in one of the ophthalmic lenses, the data processing subsystem generates a signal indicating the presence of said one of said predetermined conditions in said one ophthalmic lens.

11. The lens inspection system according to claim 10, further comprising a control subsystem to actuate the illumination subsystem to generate a respective one of the light pulses each time one of the ophthalmic lenses moves through the lens inspection position, and wherein the transport subsystem includes means to generate a trigger signal each time one of the ophthalmic lenses moves through the lens inspection position, and the control subsystem receives the trigger signal from the transport subsystem and transmits the trigger signal from the transport subsystem and transmits the trigger signal to the illumination subsystem to generate said respective one of the light pulses.

8. A lens inspection system according to claim 8, wherein:

the transport subsystem includes means to generate a trigger signal each time one of the ophthalmic lenses moves through the lens inspection position; and

the control subsystem receives the trigger signal from the transport subsystem and transmits the trigger signal to the illumination subsystem to generate said respective one of the light pulses.

12. A method of automatically inspecting ophthalmic lenses, comprising the steps of:

continuously moving a plurality of ophthalmic lenses in a lens carrier along a predetermined path to move each of those lenses into a lens inspection position;

generating a series of light pulses;

directing a respective one light pulse through each ophthalmic lens moving through the lens inspection position;

holding each of the lenses in said carrier substantially level in a fluid solution as the lens moves along said predetermined path and into said lens inspection position as one of the light pulses is directed through the lens;

focusing a first portion of each light pulse directed through the ophthalmic lens on an opaque stop, and focusing a second portion of each light pulse directed through the ophthalmic lens on a pixel array;

generating a set of signals representing selected portions of the second portion of the light pulses transmitted through the ophthalmic lenses; and

processing said signals according to a predetermined program to identify at least one condition of each of said lenses.

13. A method according to claim 12, wherein the processing step includes the steps of:

processing said signals to determine if any one of a plurality of predetermined conditions are present in each of the ophthalmic lenses; and

if any one of said predetermined conditions is found in one of the ophthalmic lenses, generating a signal indicating the presence of said one of said conditions in said one ophthalmic lens.

14. A method according to claim 12, wherein:

the moving step includes the step of generating a trigger signal each time one of the lenses moves into the lens inspection position;

the step of generating the light pulses includes the step of generating one of the light pulses each time the trigger signal is generated.

15. An automatic lens inspection system, said automatic system comprising:

a transport subsystem to move a plurality of ophthalmic lenses along a predetermined path to move each of the lenses, one at a time, into a lens inspection position;

an illumination subsystem to generate a series of light pulses and to direct a respective one light pulse through each ophthalmic lens moving through the lens inspection position;

an opaque stop positioned between the pixel array and the lens inspection position;

an imaging lens positioned between the opaque stop and the lens inspection position to focus onto the stop a first portion of the light transmitted through the lens inspection position, and to focus on the pixel array a second portion of the light transmitted through the lens inspection position; and

an imaging subsystem to generate a set of signals representing selected second portions of the light pulses transmitted through the ophthalmic lenses and to process said signals according to a predetermined program to identify at least one condition of each said lens;

wherein the transport subsystem includes

i) a lens carrier to hold the plurality of ophthalmic lenses, and

ii) a support assembly supporting the lens carrier and to move the lens carrier continuously to move each of the lenses therein, one at a time, smoothly into and through the lens inspection position.

16. A lens inspection system according to claim 15, further comprising a control subsystem to operate the illumination subsystem to generate one of the light pulses when one of the ophthalmic lenses is in the lens inspection position, and wherein the illumination subsystem includes a diaphragm to control the size of the cross-sectional area of the light pulses.

17. A lens inspection system according to claim 16, wherein:

the transport subsystem includes means to generate a trigger signal each time one of the ophthalmic lenses moves into the lens inspection position;

the imaging subsystem includes

i) a housing,

ii) a pixel array disposed in the housing, and

iii) a shutter having open and closed positions; and

the control subsystem receives the trigger signal from the transport subsystem and, in response to receiving said signal, the control subsystem

i) opens the shutter to expose the pixel array, and

ii) a predetermined length of time after opening the shutter, actuates the illumination subsystem to generate one of the light pulses.

18. A lens inspection system according to claim 17, wherein said predetermined length of time is adjustable.