Spectrometer assembly

• US 6,362,888 B1
• Filed: 06/13/2001
• Issued: 03/26/2002
• Est. Priority Date: 12/23/1999
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: LJ Laboratories L.L.C.
• Inventors: Loudermilk, Alan R., Jung, Wayne D., Jung, Russell W.
• Primary Examiner(s): EVANS, FANNIE L
• Application Number:
  US09/881,371
• Publication Number:
  US 20010043330A1
• Time in Patent Office: 286 Days
• Field of Search: 356/416, 356/417, 356/419, 356/414, 250/226
• US Class Current: 356/419
• CPC Class Codes: G01J 1/0407 Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
• CPC Class Codes: G01J 1/0433 using notch filters
• CPC Class Codes: G01J 1/0437 using masks, aperture plates, spatial light modulators, spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 1/0474 Diffusers cavities G01J2001/0481
• CPC Class Codes: G01J 1/06 Restricting the angle of incident light
• CPC Class Codes: G01J 2001/0481 Preset integrating sphere or cavity
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0205 Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/021 using plane or convex mirrors, parallel phase plates, or particular reflectors
• CPC Class Codes: G01J 3/0216 using light concentrators or collectors or condensers
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0227 using notch filters
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0251 Colorimeters making use of an integrating sphere
• CPC Class Codes: G01J 3/0259 Monolithic
• CPC Class Codes: G01J 3/0264 Electrical interface; User interface
• CPC Class Codes: G01J 3/0278 Control or determination of height or angle information for sensors or receivers
• CPC Class Codes: G01J 3/0283 using a charging unit
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/10 : Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/2803 : using photoelectric array detector
• CPC Class Codes: G01J 3/508 : measuring the colour of teeth
• CPC Class Codes: G01J 3/51 : using colour filters
• CPC Class Codes: G01J 3/513 : having fixed filter-detector pairs

Abstract

Optical characteristic measuring systems and methods such as for determining the color or other optical characteristics of teeth are disclosed. Perimeter receiver fiber optics preferably are spaced apart from a source fiber optic and receive light from the surface of the object/tooth being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object/tooth being measured. Under processor control, the optical characteristics measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence, gloss and/or surface texture data also may be obtained. Such methods and implements may be desirably utilized for purposes of detecting and preventing counterfeiting. Low cost and small form factor spectrometers, and methods for manufacturing the same, also are disclosed.

Claims

1. A spectrometer assembly comprising;

a plurality of optical sensors, wherein the plural of optical sensors include an array of sensors each of which generates a signal having a frequency proportional to the light intensity received by the particular sensor;

a plurality of interference filter elements, wherein a plurality of interference filter elements are positioned correspondingly to a plurality of the optical sensors, wherein the plurality of interface filters each substantially pass light in a predetermined spectral band or bands and reflect light outside of the predetermined band or bands, wherein collectively the plurality of interference filter elements positioned correspondingly to a plurality of the optical sensors span a predetermined spectral band or bands,

a light input;

wherein light that is input to the light input is directed to a first one of the plurality of interference filter elements positioned correspondingly to a plurality of the optical sensors, wherein a portion of the light passes through the first one of the plurality of interference filter elements and is sensed by a first one of the plurality of optical sensors, wherein light that does not pass through the first one of the plurality of interference filters is substantially reflected and propagated to a second one of the plurality of interference filter elements positioned correspondingly to a plurality of the optical sensors, wherein a portion of the light passes through the second one of the plurality of interference filter elements and is sensed by a second one of the plurality of optical sensors, wherein light that does not pass through the second one of the plurality of interference filters is substantially reflected and propagated to one or more subsequent ones of the plurality of interference filter elements positioned correspondingly to a plurality of the optical sensors and sensed by corresponding optical sensors;

wherein a plurality of the optical sensors sense light that is propagated through the spectrometer assembly, wherein a processing element receives a plurality of signals each having a frequency proportional to the light intensity received by the particular sensor, wherein the processing element generates data indicative of the spectral characteristics of the light that is input to the light input based on the plurality of signals.

2. The assembly of claim 1, wherein the light input comprises a fiber optic input.

3. The assembly of claim 2, wherein light entering the light input is collimated by a collimating element.

4. The assembly of claim 3, wherein the collimating element comprises a GRIN or aspherical lens.

5. The assembly of claim 4, wherein a collimating element is positioned in an optical path preceding each of the interference filter elements.

6. The assembly of claim 1, wherein the plurality of optical sensors and the plurality of interference elements are provided in at least two opposing arrays.

7. The assembly of claim 6, wherein light selectively is either sensed or propagated through the spectrometer assembly in a zigzag pattern.

8. The assembly of claim 1, wherein a fiber optic element is positioned in an optical path preceding each of the interference filter elements.

9. The assembly of claim 1, further comprising a plurality of mirror elements, wherein the plurality of mirror elements are positioned in an opposite and corresponding manner from the plurality of optical sensors and the plurality of interference elements.

10. The assembly of claim 9, wherein light that is input to the light input is reflected from a first one of the plurality of mirror elements and propagated to a first one of the plurality of interference filter elements positioned correspondingly to a plurality of the optical sensors, wherein a portion of the light passes through the first one of the plurality of interference filter elements and is sensed by a first one of the plurality of optical sensors, wherein light that does not pass through the first one of the plurality of interference filters is substantially reflected and propagated to a second one of the plurality of elements and propagated to a second one of the plurality of interference filters elements positioned correspondingly to a plurality of the optical sensors, wherein a portion of the light passes through the second one of the plurality of interference filter elements and is sensed by a second one of the plurality of optical sensors, wherein light that does not pass through the second one of the plurality of interference filters is substantially reflected and propagated to one or more subsequent ones of the plurality of mirror elements and to one or more subsequent ones of the plurality of interference filter elements positioned correspondingly to a plurality of the optical sensor and sensed by corresponding optical sensor.

11. The assembly of claim 9, wherein one of the mirror elements is in the optical path of each of a plurality of the optical sensors interference filter elements.

12. The assembly of claim 11, wherein the mirror elements collimate light received by the mirror elements.

13. The assembly of claim 12, wherein the mirror elements are of a nominally parabolic shape.

14. The assembly of claim 13, wherein the mirror elements are of a nominal but distorted parabolic shape.

15. The assembly of claim 1, wherein each of the signals having a frequency proportional to the light intensity received by the particular sensor comprises a digital signal.

16. The assembly of claim 15, wherein the digital signals comprises TTL or CMOS digital signal.

17. The assembly of claim 15, wherein the data indicative of the spectral characteristics of the light that is input to the light input is generated based on measuring a period of a plurality of digital signals produced by a plurality of sensors.

18. The assembly of claim 1, wherein each of the signals having a frequency proportional to the light intensity received by the particular sensor comprises an asynchronous signal of a frequency dependent upon the intensity of light received by the particular sensor.

19. The assembly of claim 1, wherein the array of sensors comprise a plurality of light to frequency converter sensing elements.

20. The assembly of claim 1, wherein the plurality of interference filter elements comprise a color gradient filter or a filter grid.

21. The assembly of claim 1, wherein light received by the light input is spectrally analyzed without using a diffraction grating.

22. The assembly of claim 1, wherein the processing element comprises a microprocessor, logic, a logic array or a programmable logic array.