High throughput optical scanner

• US 6,384,951 B1
• Filed: 04/18/2000
• Issued: 05/07/2002
• Est. Priority Date: 11/19/1997
• Status: Expired due to Fees

• Current Assignee: Washington University In St Louis
• Original Assignee: University of Washington
• Inventors: van den Engh, Gerrit J., Esposito, Richard J., Basiji, David A.
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): BOUTSIKARIS, LEONIDAS
• Application Number:
  US09/551,088
• Time in Patent Office: 749 Days
• Field of Search: 359/216, 359/196-215, 359/217-227, 356/417, 250/584, 250/585, 250/586, 250/591, 250/234
• US Class Current: 359/212.1
• CPC Class Codes: G01J 3/443 Emission spectrometry
• CPC Class Codes: G01J 3/45 Interferometric spectrometry
• CPC Class Codes: G06K 7/10801 Multidistance reading

Abstract

A scanning apparatus is provided to obtain automated, rapid and sensitive scanning of substrate fluorescence, optical density or phosphorescence. The scanner uses a constant path length optical train, which enables the combination of a moving beam for high speed scanning with phase-sensitive detection for noise reduction, comprising a light source, a scanning mirror to receive light from the light source and sweep it across a steering mirror, a steering mirror to receive light from the scanning mirror and reflect it to the substrate, whereby it is swept across the substrate along a scan arc, and a photodetector to receive emitted or scattered light from the substrate, wherein the optical path length from the light source to the photodetector is substantially constant throughout the sweep across the substrate. The optical train can further include a waveguide or mirror to collect emitted or scattered light from the substrate and direct it to the photodetector. For phase-sensitive detection the light source is intensity modulated and the detector is connected to phase-sensitive detection electronics. A scanner using a substrate translator is also provided. For two dimensional imaging the substrate is translated in one dimension while the scanning mirror scans the beam in a second dimension. For a high throughput scanner, stacks of substrates are loaded onto a conveyor belt from a tray feeder.

Claims

1. A constant pathlength optical train for coupling light to a substrate and for coupling scattered or emitted light from the substrate to a photodetector, comprising:

a light source for providing a light beam;

a scanning mirror assembly positioned to receive said light beam from said light source and sweep it across a steering mirror;

a steering mirror positioned to receive said light beam from said scanning mirror assembly and reflect it to the substrate, whereby it is swept across the substrate along a scan arc; and

a photodetector positioned to receive emitted or scattered light from the substrate;

phase-sensitive detection electronics coupled with said photodetector;

said optical train being constructed and arranged such that a substantially constant optical pathlength from the light source to the photodetector is maintained throughout the sweep of said beam across the substrate.

2. A phase-nulling scanner, comprising:

an intensity modulated light source for providing a light beam;

means for scanning said beam across a substrate;

a photodetector positioned to receive emitted or scattered light from the substrate; and

phase-sensitive detection electronics, including phase-nulling electronics, coupled with said photodetector.

3. The phase-nulling scanner of claim 2 wherein said means for scanning comprises a moving optic system.

4. The phase-nulling scanner of claim 2 wherein said means for scanning comprises a moving beam system.

5. The phase-nulling scanner of claim 4 wherein said moving beam system comprises a scanning mirror assembly positioned to receive said light beam from such light source and sweep it across said substrate.

6. The phase-nulling scanner of claim 4 wherein said moving beam system is a constant path length moving beam system.

7. The phase-nulling scanner of claim 4 wherein said moving beam detection system is a non-constant path length moving beam detection system.

8. The phase-nulling scanner of claim 2 wherein said phase-nulling electronics include a computer for mathematical phase nulling.

9. A method for removing a non-random component from a scanned optical signal, comprising:

scanning an intensity modulated light beam across a substrate;

phase sensitively detecting emitted or scattered light from said substrate, whereby a detected signal is produced having both a desired component and an undesired non-random component;

phase nulling said undesired non-random component from said detected signal.

10. The method of claim 9 wherein said undesired non-random component is a baseline signal.

11. The method of claim 9 wherein said desired component is a first luminescence signal from said substrate and said undesired non-random component is a second luminescence signal from said substrate, whereby said phase nulling removes said second luminescence signal from said first luminescence signal.