Microscope with infrared imaging

A microscope enables selective illumination using infrared or visible spectrum light. The image captured by a sensor array within the microscope may be displayed on a computer display. Some objects appear differently when exposed to infrared as opposed to visible radiation.

BACKGROUND 
This invention relates generally to microscopes with imaging capabilities. 
Such microscopes may be utilized in conjunction with computers to provide 
enlarged images of small objects. 
The X3 digital video microscope by Intel Corporation and Mattel uses a 
digital imaging device to provide a magnified color image of an object 
viewable on the display of a computer system. This product may be used by 
children to view enlarged images of objects and to transmit those images 
using electronic mail. Once the image is electronically captured, 
alteration of the image may also be possible using well known software. 
Thus, microscopes of this type provide an educational and entertaining toy 
for children. They allow children to learn more about computers and at the 
same time to learn more about the objects being imaged. 
In view of the entertainment and educational opportunities afforded by 
microscopes of this type, there is a continuing interest in more advanced 
devices which provide further educational and entertainment opportunities. 
SUMMARY 
In accordance with one aspect, a microscope may include an imaging array. A 
first light source for the microscope is adapted to selectively produce 
visible light and a second light source is adapted to selectively produce 
infrared light.

DETAILED DESCRIPTION 
Referring to FIG. 1, a computer system 10 may include an microscopic 
imaging device 12 and a computer 22 including a housing 24 and a display 
26. The microscope 12 may be coupled to the computer system 22 by a cable 
13 which may provide serial data from the microscope 12 to the computer 
system 22. In this way, data captured by the microscope 12 may be 
displayed on the display 26 of the computer 22. 
Turning now to FIG. 2, the microscope 12 may include an imaging sensor 28 
which may be a complementary metal oxide semiconductor (CMOS) imaging 
sensor in one embodiment of the present invention. The sensor 28 may also 
be a charge coupled device (CCD) imaging sensor in another embodiment of 
the present invention. In some embodiments, the imaging sensor 28 may 
capture a digital representation of an object 38 which may be positioned 
in the sample holder 16 of the microscope 12. A lens 30 may develop an 
image for capture by the imaging sensor 28. The microscope may be 
maintained in an upright orientation using a base 14. 
Some objects such as polymers and biological specimens such as leaves 
exhibit different optical properties in the infrared portion of the 
spectrum. Thus, the same object may have a different appearance as 
captured by the imaging array 28 and as displayed on the display 26 when 
viewed under infrared versus visible spectrum light. 
Typically, an imaging sensor 28 includes a color filter array (CFA) 
material. The inventor of the present invention has determined that such 
color filter array materials are readily transparent to both infrared and 
visible spectrum light. Thus, the imaging sensor 28 works with both light 
spectra. In particular, the quantum efficiency of silicon sensors is 
sufficient in both the infrared and visible spectrums. By providing a high 
efficiency infrared source, given high transmittance by the color filter 
array of the infrared light, a silicon imaging sensor is adequate for 
infrared imaging capabilities. Thus, the combined effect of the improved 
color filter array transmittance and the reduced quantum efficiency is 
such that infrared imaging by the same sensor used for visible imaging is 
feasible. 
A pair of separate light sources 40, 42 may be coupled to the computer 22 
through an interface 44. The light source 42 may be a relatively pure 
source of infrared light. The light source 40 may be a relatively pure 
white light source. The computer 22, under user command, may select one of 
the light sources 40 or 42 to illuminate the object 38 in the sample 
holder 16. 
The white light source 40 may illuminate the object 38 with white light. 
The white light is reflected off the object in the direction of the arrow 
A and is captured by the imaging array 28. The array 28 sends a digital 
representation of the information to the host computer 22. 
The user may provide an input signal to the host computer 22 to select a 
desired light source for illuminating the object. That selection may be 
passed from the computer 22 to the interface 44 to operate the appropriate 
light source 40 or 42. Alternatively, the light sources 40 or 42 may be 
selected by a switch 23 on the exterior of the microscope 12, as shown in 
FIG. 1. 
A white light emitting diode (LED) may be used as the white light source 
40. Suitable diodes include indium gallium nitride (InGaN) diodes 
available, for example, from Nichia America Corporation (Mountville, Pa. 
17554) including the Nichia NSPW500BS and NSPW300BS white light LEDs. See 
wwwla.meshnet.jp/nichia/lamp-e.htm. These devices show negligible emission 
in the infrared radiation spectrum (approximately 780 nanometers and 
higher). The chromaticity coordinates specified by the manufacturer for 
these diodes are X=0.310, Y=0.320 in the CIE (1931) standard calorimetric 
system (International Congress on Illumination, Proceedings, International 
Congress on Illumination, Cambridge, Cambridge University Press). 
For the infrared source 42, a gallium aluminum arsenide (GaAlAs) infrared 
light emitting diode may be utilized. These diodes may emit radiation at 
wavelengths of about 875 nanometers. Alternatively, gallium arsenide 
(GaAs) diodes may be used that emit radiation at wavelengths of about 940 
nanometers. Such diodes are available, for example, from Vishay 
Intertechnology Inc. (San Diego, Calif.). Examples of suitable diodes 
include the TSHA440 infrared light emitting GaAlAs diode from Vishay 
(www.vishay.de) emitting at 875 nanometers. 
Imaging optics 30, which may be a spherical lens of the type used for macro 
photography, may be positioned between the object 38 and the imaging 
sensor 28. Its position may be manually adjustable using the rotatable 
knobs 18 to allow for focusing. In some cases, the spherical lens 30 may 
be replaced with a flat lens, such as Fresnel lens, adapted for close up 
viewing. 
Since no infrared blocking filter is needed, optical efficiency and cost 
may be improved in some embodiments. Also, the reliability of LEDs is 
relatively high compared to filament lamps. 
One hardware implementation of the present invention, shown in FIG. 4, 
includes a processor-based system 10 having a processor 48 coupled to a 
bridge 50. The bridge 50 is coupled between system memory 56 and graphics 
accelerator 52. The display 26 may be coupled to the graphics accelerator 
52. 
The bridge 50 also couples a bus 58 in turn coupled to the microscope 12 
through the cable 13 to the imaging sensor 28 and its interface 60. The 
interface 60 may itself include a processor for conducting analyses on 
digital representations of the image detected by the microscope 12. 
Alternatively, as shown in FIG. 4, the interface 60 may simply interface 
the imaging array 28 with the processor 48. 
In one embodiment, a second bridge 62 couples a hard disk drive 64 or other 
non-volatile storage. The drive 64 may store image processing software 66 
for modifying and enhancing the captured images, for example using the 
graphical user interface shown in FIG. 3. 
The bridge 62 is also coupled to another bus 68 which couples conventional 
devices such as a keyboard 72 and a mouse 74 through a serial input/output 
(SIO) device 70. A binary input/output system (BIOS) 76 may also be 
coupled to the bus 68. The lamp interface 44 and lamp switch 23 may also 
be coupled through the SIO device 70. 
Referring to FIG. 3, a graphical user interface, developed by the processor 
48 under control of the software 66, may be displayed on the display 26 to 
assist the user of the host computer system 22 in utilizing the microscope 
12. For example, a pair of icons 78 and 80 may be displayed which the user 
may use to select either infrared or visible spectrum illumination. When 
the user operates the mouse cursor over the desired icon 78 or 80, the 
host computer 22 may select the appropriate illumination source 40 or 42. 
Similarly, the user can make other image modifications including brightness 
adjustments as indicated at 82, contrast as indicated at 84, hue as 
indicated at 86 and saturation as indicated at 88. Each of these input 
icons, as well as others, may operate on a simple sliding scale where 
moving the icon to the right using a mouse cursor increases the 
characteristic and moving to the left decreases the characteristic. After 
the user has made the desired adjustments, the user can return to 
displaying the captured image of the object 38 by selecting an icon 78 or 
80. 
While the present invention has been described with respect to a limited 
number of embodiments, those skilled in the art will appreciate numerous 
modifications and variations therefrom. It is intended that the appended 
claims cover all such modifications and variations as fall within the true 
spirit and scope of this present invention.