Semiconductor forensic light kit

• US 7,283,230 B2
• Filed: 04/22/2005
• Issued: 10/16/2007
• Est. Priority Date: 09/24/1999
• Status: Expired due to Term

• Current Assignee: CAO Group, Inc.
• Original Assignee: CAO Group, Inc.
• Inventors: Cao, Densen, Li, Hongyan, Ostler, Calvin D., Lin, Zhaohui
• Primary Examiner(s): Toatley, Jr.; Gregory J.
• Assistant Examiner(s): Skovholt; Jonathan
• Application Number:
  US11/112,731
• Publication Number:
  US 20050231966A1
• Time in Patent Office: 907 Days
• Field of Search: None
• US Class Current: 356/317
• CPC Class Codes: F21V 29/54 using thermoelectric means, e.g. Peltier elements
• CPC Class Codes: F21V 29/67 characterised by the arrangement of fans
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 29/83 the elements having apertures, ducts or channels, e.g. heat radiation holes
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01N 2021/6471 Special filters, filter wheel
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems
• CPC Class Codes: G01N 21/29 using visual detection G01N21/31 takes precedence
• CPC Class Codes: G01N 21/6447 by visual observation
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: G01N 2201/0221 Portable; cableless; compact; hand-held

Abstract

A semiconductor forensic light kit is disclosed. The forensic light kit may use a variety of semiconductor light sources to produce light that contrasts forensic evidence against its background for viewing, photographing and collection. Example semiconductor light sources for the forensic light kit include light emitting diodes and laser chips. A heat sink, thermoelectric cooler and fan may be included to keep the forensic light cool. Removable light source heads may be included on the forensic light kit to provide for head swapping to give the user access to different wavelengths of light.

Claims

1. A semiconductor forensic light kit comprising:

a battery charger, said battery charger being capable of charging a battery pack,

an AC wall outlet cord for providing power to said battery charger,

a DC power adapter and cord,

a semiconductor forensic light that includes

a housing having a proximal end, a distal end, a top, a bottom and an interior,

control circuitry located in said housing interior,

said control circuitry being able to control on/off and power intensity selection functions of the forensic light,

an on/off button located on the top of said housing, said on/off button being in operable connection with said control circuitry,

a power level selection button located on the top of said housing, said power level selection button accommodating the increase and decrease of light output levels from the forensic light,

said power level selection button being in operable communication with said control circuitry,

a trigger said housing, said trigger serving to accommodate initiation and terminate of light emission from the forensic light,

said trigger being in operable communication with said control circuitry,

a power pack located at said housing proximal end for providing electrical power to the forensic light,

a plurality of light heads located at said housing distal end, each of said light heads emitting light centered on a different wavelength than each of said other heads,

a light source within one of said light heads,

said light source including

a semiconductor light emitting device that can emit light of a wavelength useful in detecting forensic evidence,

a primary heat sink to which said semiconductor light emitting device is affixed, said primary heat sink serving to draw heat away from said semiconductor light emitting device,

a secondary heat sink to which said primary heat sink is affixed, said secondary heat sink serving to dissipate heat produced by said semiconductor light emitting device,

a thermoelectric cooler located on said secondary heat sink, said thermoelectric cooler experiencing a drop in temperature when subjected to a voltage, and

a fan serving to move air past said thermoelectric cooler in order to cool the light source,

at least one ventilation aperture on said light head for permitting air to enter and exit the light head to facilitating heat dissipation, and

at least one light exit on said light head, said light exit being sized and shaped to permit light to exit said light head for use in detecting forensic evidence.

2. A forensic light kit as recited in claim 1 wherein said light heads are detachable from said housing distal end.

3. A forensic light kit as recited in claim 1 wherein at least one of said light heads emits light of a wavelength centered about 450 nm.

4. A forensic light kit as recited in claim 1 wherein said semiconductor light producing device is an LED module that include the primary heat sink, an LED chip located in a well on the primary heat sink, and a dome over said LED chip, the LED chip including a substrate and epitaxial layers.

5. A forensic light kit as recited in claim 1 further comprising:

a well in said primary heat sink, and

a plurality of semiconductor light producing devices located in said well.

6. A forensic light kit as recited in claim 1 wherein at least one of said heat sinks includes a material selected from the group consisting of copper, aluminum, silver, magnesium, steel, silicon carbide, boron nitride, tungsten, molybdenum, cobalt, chrome, Si, SiO₂, SiC, AlSi, AlSiC, and diamond.

7. A forensic light kit as recited in claim 1 wherein said semiconductor light producing device includes epitaxial layers located on a substrate and wherein said substrate is selected from the group consisting of Si, GaAs, GaN, ZnS, ZnSe, InP, Al₂O₃, SiC, GaSb, and InAs.

8. A forensic light kit as recited in claim 1 wherein said semiconductor light producing device includes epitaxial layers located on a substrate, and at least one of the epitaxial layers is selected from the group consisting of:

a buffer layer to reduce defects in the chip that may arise due to differences in material properties between the epitaxial layers and the substrate,

a contact layer,

a cladding layer serving to confine injected electrons, and

an active layer that emits the light when excited by electrons, the light emitted being useful in forensic detection of evidence.

9. A forensic light kit as recited in claim 1 wherein said thermoelectric cooler includes a material selected from the group consisting of Bi₂Te₃, PbTe, SiGe, BeO₂, BiTeSe, BiTeSb, AlO₃, AlN, and BaN.

10. A forensic light kit as recited in claim 1 wherein said light head is capable of emitting light that is selected from the group consisting of blue, green, yellow, red, infrared and ultraviolet.

11. A forensic light kit as recited in claim 1 wherein light emitted by the forensic light is useful in detecting forensic evidence selected from the group consisting of blood, saliva, other body fluids, hair, flesh, bone fragments, teeth, human skin damage such as bruises, bite marks, cuts, shoe prints, fingerprints, footprints, tire prints, gunpowder residue, bullets and portions thereof, paint, grease, oil, glass fragments, metal rubbings, fibers, dust patterns, alteration of documents, narcotics, and herbal evidence.

12. A semiconductor forensic light kit comprising:

a battery charger,

a battery charger cord,

a semiconductor forensic light that includes

a housing having a proximal end, a distal end, a top, a bottom and an interior,

a plurality of light heads located at said housing distal end, each of said light heads emitting light centered on a different wavelength than each of said other heads,

each of said light heads being installable at said housing distal end,

said light heads being quick detachable from said housing in order to accommodate removal of one light head and replacement of one of the light heads with another light head by a forensic technician working in the field,

a light source within said light head,

said light source including

a semiconductor light emitting device that emits light of a wavelength useful in detecting forensic evidence,

a primary heat sink to which said semiconductor light emitting device is affixed, said primary heat sink serving to draw heat away from said semiconductor light emitting device, and

at least one light exit on said light head, said light exit being sized and shaped to permit light to exit said light head for use in detecting forensic evidence.

13. A forensic light kit as recited in claim 12 wherein said semiconductor light producing device is an LED module that include the primary heat sink, an LED chip located in a well on the primary heat sink, and a dome over said LED chip, the LED chip including a substrate and epitaxial layers.

14. A forensic light kit as recited in claim 12 wherein said heat sink includes a material selected from the group consisting of copper, aluminum, silver, magnesium, steel, silicon carbide, boron nitride, tungsten, molybdenum, cobalt, chrome, Si, SiO₂, SiC, AlSi, AlSiC, and diamond.

15. A forensic light kit as recited in claim 12 wherein said semiconductor light producing device includes epitaxial layers located on a substrate and wherein said substrate is selected from the group consisting of Si, GaAs, GaN, ZnS, ZnSe, InP, Al₂O₃, SiC, GaSb, and InAs.

16. A semiconductor forensic light kit comprising:

a power cord,

a forensic light that includes

a handle,

a plurality of light heads locatable at said housing distal end, at least one of said light heads emitting light centered on a different wavelength than at least one of said other heads,

at least one of said light heads being attachable to and removable from said housing,

a light source within said light head,

said light source including

a semiconductor light emitting device that emits light of a wavelength useful in detecting forensic evidence,

a primary heat sink to which said semiconductor light emitting device is affixed, said primary heat sink serving to draw heat away from said semiconductor light emitting device, and

at least one light exit on said light head, said light exit being sized and shaped to permit light to exit said light head for use in detecting forensic evidence.