HK1149182A - Optical device components - Google Patents

Description

Optical device assembly

Technical Field

This application claims priority from U.S. provisional patent application serial No. 60/972,121, filed on 13/9/2007, which is hereby incorporated by reference in its entirety.

Background

Whether the sample is a gas, liquid or solid, its basic property is that it is prone or not to absorb or scatter light of a particular wavelength. Characterization of the propensity of a sample to absorb, scatter or transmit is the basis for many optical measurements and instruments (e.g., spectrophotometry). The accuracy and repeatability of measurements made using optical means involves many factors, including the strength of the signal reaching one or more detectors. The optical device may be used to measure the presence and amount of a component in human or animal blood or interstitial fluid. In one example, a non-invasive optical device may use some form of spectroscopy to acquire a signal or spectrum from a target region of a user's body.

The american diabetes association reports that more than six percent (6%) of americans, i.e., more than 1,7000,000, have diabetes. According to scientists at the diabetes control center ("CDC"), one third of the children born in the united states in 2000 will be diabetic unless more people begin to eat less and exercise more. One CDC study revealed that there were approximately 1,100,000 diagnosed cases of diabetes in 2000, and the number of diagnosed cases would rise to 2,900,000 by year 2050.

An important element of diabetes management is the self-monitoring of blood glucose concentrations by diabetics in a home environment. However, current monitoring techniques prevent normal use due to the inconvenient and painful nature of drawing blood or interstitial fluid through the skin prior to analysis. As a result, beneficial development of noninvasive blood glucose concentration measurement and diabetes management is desired.

There are many non-invasive methods for blood glucose determination. A non-invasive blood chemistry detection technique involves the collection and analysis of spectral data. Since other components (e.g. skin, fat, muscle, bone, interstitial fluid) are present in addition to blood in the region being sensed, extracting information about blood characteristics (e.g. blood glucose concentration) from spectral or other data obtained from spectroscopy is a complicated problem. Such other components can affect these signals in such a way as to change the reading (reading). In particular, the amplitude of the resulting signal may be much greater than the amplitude of the portion of the signal corresponding to blood, thus limiting the ability to accurately extract blood characteristic information.

Disclosure of Invention

Embodiments of the present invention relate to a light illumination funnel (light illumination funnel). The funnel includes a first opening positioned to receive an incoming light source, a second opening positioned opposite the first opening and having a smaller diameter than the first opening, and a reflective inner wall in contact with the first opening and the second opening. The funnel has a half angle of less than 25 degrees.

Embodiments are directed to a light collection funnel comprising a first opening positioned to receive an incoming sample light source, a second opening positioned opposite the first opening and having a diameter smaller than the first opening, and a reflective inner wall in contact with the first opening and the second opening.

Embodiments are also directed to an apparatus comprising a light source configured to generate a plurality of light beams, each of the plurality of light beams having a different wavelength range, and an illumination funnel for collecting the plurality of light beams through an inlet having a first diameter and for focusing and directing the plurality of light beams to a target area through an outlet having a second diameter, wherein the second diameter is smaller than the first diameter. The apparatus also includes a light collection funnel for collecting the plurality of light beams emanating from the target area at a second entrance having a third diameter and for directing the plurality of light beams through a second exit having a fourth diameter, wherein the third diameter is smaller than the fourth diameter, a detector including a plurality of light sensing devices, each light sensing device configured to detect a light beam directed through the second exit and to generate an output signal indicative of the power of the detected light, and a processor for analyzing the output signal and generating measurement data.

Drawings

In the drawings, which are not necessarily drawn to scale, like reference numerals describe substantially similar components throughout the several views. Like reference numerals having different letter suffixes represent different instances of substantially similar components. The accompanying drawings illustrate, by way of example and not by way of limitation, various embodiments discussed herein.

Fig. 1A-B illustrate plots of pulse waves corresponding to light absorption by arterial blood, according to some embodiments.

FIG. 2 illustrates an optical construction according to some embodiments.

Fig. 3 illustrates an existing optical configuration for performing optical measurements of biological samples, according to some embodiments.

Fig. 4 illustrates an optical configuration for performing optical measurements of a biological sample, according to some embodiments.

Fig. 5 illustrates a cross-sectional view of a light funnel according to some embodiments.

FIG. 6 illustrates components of a light source according to some embodiments.

Fig. 7 illustrates a cross-sectional view of a light funnel having a matrix of infrared emitting diode (IRED) arrays disposed therein, according to some embodiments.

Detailed Description

The following detailed description includes a discussion of the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments, which are also referred to herein as "examples," are described in sufficient detail to enable those skilled in the art to practice the invention. These embodiments may be combined, other embodiments may be utilized, or structural and logical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.

As used herein, the terms "a" or "an" are intended to include one or more than one, and the term "or" is intended to mean a non-exclusive "or," unless otherwise indicated. Also, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Further, all publications, patents, and patent documents cited herein are incorporated by reference in their entirety. In the event of inconsistencies between the documents so incorporated by reference and used herein, the usage in the incorporated references shall be considered to be complementary to the usage in the present document; for inconsistent inconsistencies, the definitions are used in this document.

Embodiments of the present invention relate to optical assemblies, such as light funnels for illumination and measurement of optical properties of samples. Although illustrated with respect to spectroscopic samples of human or animal body regions, embodiments are directed to all types of optical instruments, including optical detectors, microscopes, spectrometers, and the like. Spectroscopy can be used to determine the amount of light absorbed by a biological sample (e.g., a human finger). By measuring the amount of light absorbed by the finger, the glucose, cholesterol and hemoglobin levels of a person can be determined non-invasively. Fingertip measurements are generally preferred because of the high concentration of capillaries in the fingertip and the conversion from arterial to venous blood that occurs in the fingertip.

When light is transmitted through a biological sample, such as a human finger, the light is absorbed and scattered by various components of the finger, including skin, muscle, bone, fat, interstitial fluid, and blood. However, it was observed that light absorption by a human finger exhibits a small range of cyclic patterns corresponding to the heartbeat. Fig. 1A depicts a plot 102 of a pulse wave corresponding to light absorption of arterial blood in a capillary due to a user's heartbeat. Although the amplitude of the cyclic pattern is small compared to the total current produced by the detector, considerable information can be extracted from the cyclic pattern of the plot 102. For example, assuming a person's heart rate is 60 beats per minute, the time between the start of any pulse beat and the end of that pulse beat is one second. During this one second period, the plot will have a maximum or peak 104 reading and a minimum or valley 106 reading. The peak 104 reading of the plot corresponds to when the blood in the capillary is at a minimum and the valley 106 reading corresponds to when the blood in the capillary is at a maximum. By using the optical information provided by the peaks and valleys of the circulation plot, light absorption and scattering by major finger components not in the capillaries (e.g. skin, fat, bone, muscle and interstitial fluid) is excluded. These main components that are not in the capillaries are excluded since they are unlikely to change during the one second interval. In other words, light absorbed by blood may be detected based on the peaks and valleys of the plot 102.

Assuming that the light sensing device generatesHas a peak value of circulating photocurrent of I_pAdjacent valley of circulating photocurrent is I_VThe photocurrent generated by the light sensing device under the condition of no finger of a person is I₀Then, the transmittance corresponding to the peak photocurrent and the valley photocurrent may be defined as follows:

the corresponding peak and valley absorbances (absorbances) are:

A_V＝-log(T_V) (3)

A_p＝-log(T_p) (4)

A_Vand A_pThe difference reflects the light absorption and scattering only by the blood in the finger:

the algorithm shown in equation (5) only requires monitoring the photocurrent variation to determine the optical power variation transmitted through the finger. As a result, it is not necessary to determine the photocurrent generated by the light sensing device in the absence of a human finger.

Unfortunately, since the cyclic mode is a very small signal, the amplitude of the cyclic mode (i.e., the difference between the peak and valley) is typically 1% to 3% of the total optical power transmitted through the finger. Fig. 1A shows a cyclic pattern on an enlarged scale. FIG. 1B depicts a more accurate reflection of a cyclic pattern in terms of signal amplitude. In order to obtain a 100: 1 signal-to-noise (S/N) ratio when determining Δ A, the absorbance (peak-to-peak) of the baseline noise (baseline noise) of the device used to measure light absorption by the finger should not be greater than 3.0 × 10 within a 10Hz bandwidth^-5。

However, it is difficult to obtain 3.0 x 10 within the 10Hz bandwidth with low optical power levels used by some batteries powering the handheld non-invasive blood chemistry measurement device^-5Absorbance (peak-to-peak) baseline noise level. One solution involves increasing the illumination power. However, due to size limitations of some devices, the illumination power may not be increased to achieve the desired baseline noise level (e.g., battery drain), or may not be increased enough to achieve the desired baseline noise level. Thus, the systems and methods described require an increase in the amount of optical power that can be detected by such devices without significantly increasing device size and battery power consumption.

Fig. 2 is a simplified block diagram illustrating components of a current optical measurement system 200, the optical measurement system 200 using the "pulsation" concept to determine the amount of light absorbed and scattered only by blood in a human finger. A power source 201, such as a battery, supplies power to a light source 202 that produces a plurality of light beams 204, 206, 208, 210 that are directed toward the top of the user's finger. According to one aspect of the optical measurement system 200, the beams 204, 206, 208, 210 each have a different wavelength or different wavelength range, typically within 800nm to 1800 nm. For example, first light beam 204 may have a wavelength range between 850 nanometers and 900 nanometers ("nm"), second light beam 206 may have a wavelength range between 875nm and 940nm, third light beam 208 may have a wavelength between 920nm and 980nm, and fourth light beam 210 may have a wavelength between 950nm and 1050 nm. Although the optical measurement system 200 is described herein as producing four (4) beams, in other embodiments, it is contemplated that the light source 202 may be modified to produce fewer beams or additional beams.

The first aperture 212 ensures that the beams 204, 206, 208, 210 are incident on the target area of the finger. The second aperture 214 ensures that the beam is transmitted through a portion of the finger to be incident on the lens 216. The components of the finger and optical measurement system 200 attenuate the beams 204, 206, 208, 210, and thus, the attenuated beams 218, 220, 222, 224 are emitted from the finger. The attenuated beams 218, 220, 222, 224 are incident on the lens 216, and the lens 216 collects the attenuated beams 218, 220, 222, 224 so that they are more efficiently incident on the detector block 226.

The detector block 226 is positioned directly below the lens 216 and includes a plurality of Light Sensing Devices (LSDs) 228, 230, 232, 234, such as photodiode arrays. In accordance with one aspect of the optical measurement system 200, each of the light sensing devices 228, 230, 232, 234 respectively detects a particular wavelength of light defined by the corresponding interference filter 236, 238, 240, 242. Interference filters transmit one or more spectral bands or light and block other spectral bands or light.

Each of the light sensing devices 228, 230, 232, 234 generates a corresponding current signal proportional to the power of light received by the particular light sensing device. The current signal generated by the photodiode may be converted to another form of signal, such as an analog voltage signal or a digital signal.

The processor 243 is coupled to the detector block 226 and is configured to calculate the change in the photocurrent signals 244, 246, 248, 250.

According to one aspect, the processor 243 executes an algorithm such as that shown in equation (5) to calculate the change in light absorption (Δ a) caused only by blood in the finger. This quantitative calculation of the light absorption of the blood can then be used to determine the properties of the blood. For example, by comparing the calculated optical absorption value to predetermined values corresponding to different glucose levels stored in a memory (not shown), the user's glucose level may be determined.

Referring now to fig. 3, a configuration of a conventional apparatus for measuring the amount of light absorbed by a human finger. An infrared light emitting diode ("IRED") block 302 includes multiple IRED that generate near infrared ("NIR") radiation or a 850nm to 1100nm beam. The generated NIR beam enters an entrance aperture (entry aperture)304 and passes through the finger. The NIR light beam transmitted through the finger passes through an exit aperture (exit aperture)306 onto a lens 308. The lens 308 collimates the beams and projects them onto a filter array 310 and then onto a detector array 312. The device further comprises a wall housing 314 for preventing stray light from reaching the light detector.

In this optical configuration, the light beams passing through the exit aperture 306 are thoroughly mixed in wavelength. More specifically, the entire optical power distribution of 850nm to 1100nm is transmitted to each detector in the detector array 312.

As described below, the problem with the device configuration depicted in fig. 3 is that the effectiveness of the device is hampered, resulting in potentially high baseline noise.

Low power of illumination

To accommodate the small finger size of a child, light should enter the finger through an entrance aperture 304 that is about 0.25(1/4) inches or less in diameter, and light transmitted through the finger should be collected through an exit aperture 306 that is about 0.25(1/4) inches or less in diameter. However, the number of IRED that can be placed into a 0.25 inch diameter region is limited. For example, only four 3 millimeter (mm) diameter IREDs may be effectively placed into a 0.25 inch diameter area of the entrance aperture 304. Since the average power from each IRED is about 2.5 milliwatts (mW) at half-power emission angles of fifteen (15) to twenty (20) degrees, the total available power from each IRED into the finger is about fifty percent (50%) or 1.25 mW. Thus, for four (4) IRED's, the total available power is about five (5) mW (e.g., 4 × 2.5mW x. 50) over the entire wavelength range covered by the four IRED's, typically 850nm to 1100 nm.

Absorption and scattering by human fingers

Typically, as mentioned above, skin, fat, muscle, blood and bone will attenuate the light entering the finger. For example, it was observed that absorption and scattering of light by a human finger can reduce the power of transmitted light in the NIR region of 850nm to 1100nm by a factor of about 200. As a result, the total IR power transmitted through the finger is only about 25 microwatts (μ W) (e.g., 5mW/200) over the entire wavelength region covered by the four IRED's, typically 850nm to 1100 nm.

Small collection cube corner for coupling optics

Light is emitted from the exit aperture 306 in all directions in a 2 pi solid angle under the finger. In conventional optical designs, it is difficult to collect most of the optical power transmitted through the finger, since the exit aperture 306 cannot be treated as a point source of light. Typically, the total optical power collected using the optical layout shown in fig. 3 is only about 10%, or the power decreases by a factor of 10, i.e. becomes 2.5 μ W, over the entire wavelength region covered by four IREDs, typically 850nm to 1100 nm. Note that this is the optical power sent to all detectors in fig. 3.

Number of detectors

Moreover, an optical system, such as that shown in fig. 3, may require twenty (20) to thirty (30) so many diode detectors to obtain accurate information about the chemical composition in the blood. Thus, the optical power entering each detector will be about 125nW or less.

Narrow band pass filter

The interference filter placed on top of each detector typically has a full width at half maximum (FWHM) bandwidth of 10nm, which reduces the optical power by a factor of 25, i.e. to 5nW, assuming a uniform power distribution over the entire wavelength region of 850nm to 1100 nm. Further, the peak transmittance of each interference filter is about 50% or less. Thus, the optical power received by each detector is reduced to about 2.5nW or less.

Photoelectric conversion efficiency

The photoelectric conversion efficiency of silicon diode detectors ranges from 0.1 ampere/watt (A/W) at 1100nm to about 0.5A/W at 900 nm. As a result, each detector generates a photocurrent in the range of 0.25 nano-amperes (nA) or less to 1.25nA or less, depending on the intermediate wavelength (central wavelength) of the corresponding interference filter, for each detector. The corresponding high-end shot noise within the 10Hz bandwidth is about 2.0 x 10^-4An absorbance (p-p) or more exceeding 6 times an absorbance required for accurately determining the value of Δ a defined by equation (5) at an S/N ratio of 100. In other words, to achieve the desired S/N ratio of 100: 1 for Δ A, the optical power received by the detector should be increased by more than 40 times.

Fig. 4 illustrates an optical configuration for performing optical detection of a biological sample in accordance with one aspect of the present optical measurement system 400. The light source 402 generates a plurality of light beams 404, 406, 408, 410. The light source 402 may be, for example, an incandescent light source or an infrared light emitting diode. According to one aspect of the optical measurement system 400, each of the beams 404, 406, 408, 410 has a different wavelength or a different range of wavelengths. For example, first light beam 404 may have a wavelength range between 850 and 920 nanometers ("nm"), second light beam 406 may have a wavelength range between 900nm and 980nm, third light beam 408 may have a wavelength between 970nm and 1050nm, and fourth light beam 410 may have a wavelength between 1030nm and 1100 nm. The total wavelength range may include, for example, from about 800nm to about 1200 nm. Although the optical measurement system 400 is described herein as producing four (4) beams, it is contemplated that the light source may be modified to produce fewer beams or additional beams in other embodiments.

Light beams 404, 406, 408, 410 from the light source 402 enter the illumination funnel 412 through an inlet 414 and exit the illumination funnel 412 through an outlet 416. The diameter of the outlet 416 of the illumination funnel 412 is less than or equal to the diameter of the inlet 414. For example, according to one embodiment, the diameter of the inlet 414 is about 0.625(5/8) inches and the diameter of the outlet 416 is about 0.25(1/4) inches. Thus, unlike the configuration depicted in FIG. 3, the illumination funnel 412 focuses the light beams 404, 406, 408, 410 in the same general direction toward the top of the user's finger. The illumination funnel can significantly increase the total optical power received by the target area compared to the configuration of fig. 3, thus greatly increasing the signal-to-noise ratio.

Fig. 5 depicts a cross-sectional view of the illumination assembly or funnel 412. According to one aspect, the illumination funnel 412 has a substantially cylindrical outer wall 502 with a diameter D1, a first opening 504 defined by an inner wall 506 that is frustoconical in shape, and two light inlet/outlets 508 and 504. Opening 508 (second opening) has a smaller diameter D3 and opening 504 (first opening) has a larger diameter D2. The separation distance between the two light openings is L and the half angle of the truncated cone of the inner surface is α. According to one embodiment of the invention, the value of the half angle α ranges from 10 to 15 degrees. The half angle may, for example, be less than about 25 degrees. The illumination funnel 412 may be formed from a plastic, metal, or other suitable material or compound/layer of materials having any desired index of refraction. According to one aspect, the illumination funnel 412 is formed of metal and may make the surface of the inner wall 506 highly reflective. When configured appropriately, the light intensity at the exit 508 may be increased by a factor of 50 to 100 relative to the light intensity at the entrance 510.

FIG. 6 depicts components of a light source 402 according to one aspect of an optical measurement system 400. The circuit board may be positioned adjacent to or in contact with the first opening of the funnel and may include a light source mounted on or in contact with the circuit board. In one example, multiple IREDs 602, 604, 606, and 608 are mounted to a Printed Circuit Board (PCB) 610. The PCB 610 receives power through a power line 612 connected to a power source (e.g., the power source 201) such as a battery. When power is supplied through power line 612, each of IREDs 602, 604, 606, and 608 receives power and generates multiple light beams (e.g., light beams 404, 406, 408, 410). It is apparent that IREDs with similar operating currents can be connected in series to increase battery life. The light source may be mounted in or above the funnel, for example by surrounding the light source with, for example, a housing.

According to one aspect, the light funnels 412 may be mounted to the PCB 610 by screws, posts, or other connection means. The frustoconical shape of the inner surface of the illumination funnel 412 serves to focus and focus the light beams 404, 406, 408, 410 from the IREDs 602, 604, 606, 608 into a generally conical light beam toward the finger.

FIG. 7 depicts a cross-sectional view of another embodiment of an illumination funnel 412 having a three-dimensional (3-D) IRED array matrix 702 disposed therein. Multiple light sources, such as IREDs, may be positioned in a three-dimensional layer and arranged to optimize light intensity. The light sources may be positioned in, for example, a horizontal layer and a vertical layer. According to this embodiment, there are a total of twenty-six (26) IREDs included in the 3-D array matrix. IRED is arranged in four (4) layers. The first row, as shown at 704, includes four (4) IRED's (two IRED's not shown), the second layer, as shown at 706, includes five (5) IRED's (two IRED's not shown), the third layer, as shown at 708, includes seven (7) IRED's (four IRED's not shown), and the fourth layer, as shown at 710, includes ten (10) IRED's (six IRED's not shown). Power line 712 supplies all IREDs. According to other embodiments, other IRED patterns (patterns) may also be utilized. Any number of light sources or layers may be utilized to optimize light intensity.

Since IRED is optically transparent to infrared light, the light loss due to blocking effects within the funnel cavity should be low, and the structure shown in fig. 7 is expected to collect more than 85% of the optical power emitted from the IRED 3-D array in the light funnel cavity. As a result, the total optical power of 0.25 inch diameter transmitted through the outlet 416 of the illumination funnel 412 should be about 55mW (e.g., 26X 2.5mW X0.85). Thus, the total optical power transmitted through the 0.25 inch opening above the finger in the present optical measurement system 400 is approximately eleven (11) times the corresponding power (e.g., 5mW) to reach the aperture 306 of the configuration described with reference to FIG. 3. Also, the increased optical power received at the finger will increase the amount of optical power that can be transmitted through the finger, thus increasing the optical power that is detectable at the detector block 432.

Referring back to fig. 4, the finger and components of the optical measuring system 400 attenuate the light beams 404, 406, 408, 410, and thus, the attenuated light beams 418, 420, 422, 424 are emitted from the finger. Attenuated light beams 418, 420, 422, 424 emitted from the fingers enter light-collecting funnel 426 through entrance 428 (first opening) and exit light-collecting funnel 426 through exit 430 (second opening). The diameter of the entrance 428 of the light collection funnel 426 is less than or equal to the diameter of the exit 430. For example, according to one embodiment, outlet 430 has a diameter of about 0.625(5/8) inches and inlet 428 has a diameter of about 0.25(1/4) inches. As a result, light collection funnel 426 more efficiently collects attenuated light beams 418, 420, 422, 424 and distributes them across detector block 432.

The structure of the light collection funnel 426 may be substantially similar to the structure of the illumination funnel 412 depicted in fig. 5. For example, the light collection funnel 426 has a substantially cylindrical outer wall 502 and a central opening (central opening)504 defined by an inner wall 506 that is frustoconical in shape. The light funnel collector 426 may also be formed of plastic, metal, or other suitable material or compound/layer of materials having any desired index of refraction. According to one aspect, the light collection funnel 426 is formed of metal and highly reflective to the surface of the frustoconical shaped inner wall. It was observed that the total collection efficiency of the light collection funnel 426 was over 80%, which is 8 times the total collection efficiency obtained using the conventional optical collection structure shown in fig. 3. The optical power received by the finger may be increased by a factor of about 40 to about 80 using the combination of illumination funnel 412 and light collection funnel 426, as compared to the optical configuration in fig. 3.

The detector block 432 is positioned below the outlet 430 of the light collection funnel 426 and includes a plurality of light sensing devices (e.g., light sensing devices 228, 230, 232, 234), such as a photodiode array. In accordance with one aspect of the optical measurement system 400, each light sensing device detects light of a particular wavelength defined by a corresponding interference filter placed on top of the detector.

A processor (e.g., processor 243) may be coupled to detector block 432 and configured to calculate a change in the current signal generated by the light sensing device. For example, as described above with reference to fig. 2, processor 232 executes an algorithm (e.g., shown in equation (5)) to calculate the change in light absorption (Δ a) caused only by blood in the finger. This quantitative calculation of the light absorption of the blood can then be used to determine the properties of the blood.

Embodiments of the invention may also include methods of using the illumination funnel, light collection funnel, or apparatus described herein. The light source may be in contact with the target through an illumination funnel sufficient to produce transmitted, transflective, or reflected light. For example, transmitted, transflective, or reflected light may enter a light collection funnel and be directed to one or more detectors.

Claims (17)

1. An illumination funnel, comprising:

a first opening positioned to receive an incoming light source;

a second opening positioned opposite the first opening and having a diameter smaller than the first opening; and

a reflective inner wall in contact with the first opening and the second opening;

wherein the funnel has a half angle of less than 25 degrees.

2. The illumination funnel of claim 1, wherein the funnel has a half angle of about 10 degrees to about 15 degrees.

3. The illumination funnel of any one of claims 1 or 2, further comprising a printed circuit board positioned adjacent to or in contact with the first opening.

4. The illumination funnel of any of claims 1-3, further comprising a plurality of light sources positioned proximate to the first opening.

5. The illumination funnel of claim 4, wherein the light source is in contact with a printed circuit board.

6. The illumination funnel of claim 4, wherein the light source comprises an infrared light emitting diode.

7. The illumination funnel of claim 4, wherein the light sources are positioned in a three-dimensional arrangement.

8. The illumination funnel of claim 6, wherein the three-dimensional arrangement comprises light sources positioned in horizontal and vertical layers.

9. The illumination funnel of claim 4, wherein the light source comprises an incandescent light source.

10. A light collection funnel, comprising:

a first opening positioned to receive an incoming sample light source;

a second opening positioned opposite the first opening and having a diameter greater than the first opening; and

and a reflective inner wall contacting the first opening and the second opening.

11. The light collection funnel of claim 10, further comprising one or more detectors positioned near or in contact with the second opening.

12. The light collection funnel of claim 11, wherein the one or more detectors comprise a detector array.

13. The light collection funnel of claim 11, further comprising one or more filters, gratings, or lenses positioned between the funnel and the one or more detectors.

14. An apparatus, comprising:

a light source configured to generate a plurality of light beams, each of the plurality of light beams having a different wavelength range;

an illumination funnel for collecting the plurality of light beams through an inlet having a first diameter and for focusing and directing the plurality of light beams to a target area through an outlet having a second diameter, wherein the second diameter is smaller than the first diameter;

a light collection funnel for collecting the plurality of light beams emanating from the target area at a second entrance having a third diameter and for directing the plurality of light beams through a second exit having a fourth diameter, wherein the third diameter is smaller than the fourth diameter;

a detector comprising a plurality of light sensing devices, each light sensing device configured to detect a light beam directed through the second outlet and to generate an output signal indicative of the power of the detected light; and

a processor for analyzing the output signal and generating measurement data.

15. The apparatus of claim 14, wherein the light source comprises one or more light emitting diodes.

16. The apparatus of any of claims 14 or 15, wherein the wavelength ranges comprise different wavelength ranges between about 800nm to 1200 nm.

17. The apparatus of any one of claims 14-16, wherein the light source is positioned at an entrance of an illumination funnel.