Patent Publication Number: US-8537343-B2

Title: Spectrometer miniaturized for working with cellular phones and other portable electronic devices

Description:
This is a Continuation of application Ser. No. 12/734,607, filed May 12, 2010, which is a nonprovisional of U.S. Provisional Patent Application No. 61/004,959 filed in the U.S. Patent and Trademark Office on Nov. 30, 2007. The disclosures of the prior applications are hereby incorporated by reference herein in their entirety. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to the domains of optical spectroscopy and cellular phones or other portable electronic devices. In one particular aspect, this invention relates to spectrometers miniaturized for working with cellular phones and other portable electronic devices. In another particular aspect, this invention relates to a cellular phone or other portable electronic device that has a miniaturized spectrometer being built-in or attached. 
     2. Description of the Related Prior Art, Compact Spectrometers 
     Instruments used for spectroscopic measurements and applications belong to one family of spectrometers. A spectrometer is an optical instrument for measuring and examining the spectral characteristics of the input light over some portion of the electromagnetic spectrum, where the measured variable is often the light intensity. 
     A typical optical system of a spectrometer basically comprises an element(s) for collimating, an element(s) for dispersing and an element(s) for focusing to form spectral images. The entrance slit of a spectrometer functions as the input interface, where an optional input optics exists, and divergent input optical beams are fed into the spectrometer. In order to maximize the throughput efficiency, apertures of all optical elements within the spectrometer have to be large enough to accept full optical beams without truncation, which in return, leads to a three-dimensional propagation path. Its detector, usually a (linear) CCD mounted at its spectral image plane, converts optical signals to electronic signals, allowing an instant full spectrum of the input light being acquired since a spectrometer does not have a moving parts for scanning. All of these make a spectrometer, as a useful spectroscopic instrument, cumbersome (i.e. complex in construction), large in body volume and heavy in weight. Moreover, there exist a couple of technical problems inherently associated with this kind of spectrometer: astigmatism over the spectrum on the detector plane, and field curvature from the spectrum focused onto the detector plane, as reviewed by U.S. Pat. No. 5,880,834 (1999) to Chrisp. 
     As a result, it has become challenge to design and build a spectrometer with innovative features to overcome the drawbacks and technical problems identified above, to which, substantial efforts have been directed and numerous improvements have been published for the purposes of simplifying its optics, minimizing its body volume, reducing its weight, and eliminating optical aberrations, mainly astigmatism and field curvature. Among those areas of concerns, constructing compact spectrometers has generated manifold attentions since the trend in modern spectrometer systems is towards a compact one. A compact spectrometer has the potential to open up for more applications in many industries, as discussed below. 
     Representatives of the art can be categorized in accordance with their construction features associated with compact spectrometers: spectrometers of simple optics, spectrometers of a monolithic career body, and spectrometer constructed with a waveguide substrate. 
     A representative of the art for spectrometers of simple optics is U.S. Pat. No. 4,568,187 (1986) to Kita et la, which discloses a compact spectrometer comprising a single concave grating. The concave grating is manufactured with curved grooves of varied spacing for optimum performance, and functions for both dispersing and imaging. It has become a known art that a concave grating sets the minimum number of optical elements needed in a spectrometer, leading to a simplest structure form. 
     Another representative of the art for spectrometers of simple optics is U.S. Pat. No. 6,606,156 (2003) to Ehbets et la., which discloses a compact spectrometer comprising a concave grating, mounted on one side of the housing. The input port and the detector array are positioned opposite the concave grating, leaving a hollow cavity where the input optical beams propagate. 
     Another representative of the art for spectrometers of simple optics is U.S. Pat. No. 7,081,955 (2006) to Teichmann et la, which discloses a compact spectrometer comprising two parts: the main body with grating and the focusing element being formed on the top of the housing, and the bottom substrate of detector array with light entrance means. The integrated spectrometer has a hollow cavity where the input optical beams propagate. 
     Other representatives of the art for spectrometers of simple optics are U.S. Pat. No. 5,424,826 (1995) to Kinney, which discloses an optical micro-spectrometer system, and U.S. Pat. No. 5,550,375 (1996) to Peters et la, which discloses a compact spectrometer designed as infrared spectrometric sensor. Features in common for these two disclosures are that they are constructed for specific applications. 
     Among the representatives of the art for spectrometers of simple optics, one that has to be referenced is the Japanese Patent Application Publication JP 55-093030 A (1980) to Hasumi Ritsuo, which discloses a cylindrical-lens type spectrometer. Features for this publicized disclosure are that individual cylindrical lenses are used, which manipulate light beams in the vertical and horizontal directions separately, to construct a spectrometer with a compact volume profile. 
     A representative of the art for spectrometers of a monolithic career body is U.S. Pat. No. 5,026,160 (1991) to Dorain et la, which discloses a such solid monolithic spectrometer that utilizes the Czerny-Turner configuration on a base constructed of BK7 optical glass, to which all components are affixed with optical epoxy, leading to a compact spectrometer with a robust body of thick slab form. Its light entrance means and light detecting means are both placed on the same side of the spectrometer. Another representative of the art for a spectrometer built in a similar approach is disclosed in U.S. Pat. No. 5,754,290 (1998) to Rajic et la, which has an appearance of a solid, rectangular, three-dimensional body of translucent material with defined surfaces. 
     Another representative of the art for spectrometers of a monolithic career body is U.S. Pat. No. 5,159,404 (1992) to Bittner, which discloses a spectrometer where the concave grating and focusing mirror are combined together on one side of a single glass carrier, and the light entrance means and light detecting means are both placed on the other side of the spectrometer, resulting in a compact spectrometer with a robust body of spherical form. 
     Another representative of the art for spectrometers of a monolithic career body is U.S. Pat. No. 6,081,331 (2000) to Teichmann, which discloses a spectrometer that utilizes the Fastie-Ebert geometry on a cylinder body of glass, on which a concave mirror surface for collimating and focusing is formed at one end, the light entrance means and light detecting means, as well as the planar reflective grating, are placed on the other end of the career body. 
     A representative of the art for spectrometers constructed with a waveguide substrate is U.S. Pat. No. 4,744,618 (1988) to Mahlein, which discloses a device designed as multiplexer/demultiplexer for fiber communication systems. It is constructed on a very thin piece of solid monolithic glass. In principle, it works like a compact spectrometer since its input light propagates laterally along the Fastie-Ebert geometry. Meanwhile, its light propagation path is confined vertically based on total internal reflection between two interfaces of glass and the air. A waveguide substrate of sandwich structure is also reported as an alternative embodiment. 
     There exist a few other representatives of the art for spectrometers constructed with a waveguide substrate, including: U.S. Pat. No. 4,999,489 (1991) to Huggins, and U.S. Pat. No. 5,493,393 (1996) to Beranek et la for optical fiber application. Both of them disclose waveguide based WDM sensing systems. Their optics comprise a thin layer of waveguide as the light propagation media, and a single concave grating formed at the end of the device opposite to the input and output fiber ports. 
     Another representative of the art for spectrometers constructed with a waveguide substrate is U.S. Pat. No. 4,938,553 (1990) to Maerz et la, which discloses an integrated optical spectrometer having an arrangement of either a film waveguide plus a curved, ribbed waveguide, or only a film waveguide, wherein waveguide structure and ribbed grating are manufactured by etching. The dispersed spectral signals are preferably coupled into output fibers. 
     Another representative of the art for spectrometers constructed with a waveguide substrate is U.S. Pat. No. 5,812,262 (1998) to Ridyard et la, which discloses a spectrometer for UV radiation. Constructed by a single piece of waveguide carrier, its optics comprises a concave mirror and a reflective planar grating for focusing light from the entrance aperture means onto the radiation detector means. This configuration relies on a fixed order of the optical elements of focusing and then dispersing the light, which makes it difficult to compensate or avoid aberrations. 
     Another representative of the art for spectrometers constructed with a waveguide substrate is U.S. Pat. No. 7,034,935 (2006) to Kruzelecky, which discloses an infrared spectrometer comprising: a slab waveguide structure having a front input face, a rear concave face, and an output face, a diffraction grating provided on the rear concave face for diffracting the optical signal and directing spectral components onto the output face towards a detector array that is optically coupled to a slab waveguide structure. 
     As discussed above, most of the related art of compact spectrometers, including those classical spectrometers of simple optics and a monolithic career body, are still considered “cumbersome” and large in volumes for being integrated into a cellular phone to form a standalone system. Exceptions are: (1) the cylindrical-lens type spectrometer, and (2) waveguide based spectrometers, whose volumes are the smallest. Therein the volume difference is caused by the fact that a classical spectrometer is constructed with optical elements of finite two-dimensional apertures and has a light propagation path that is three-dimensional, leading to a larger three-dimensional volume, while in a cylindrical-lens type spectrometer light propagation paths are basically two-dimensional, and for a waveguide based spectrometer it is constructed from a thin monolithic glass substrate where exists a light propagation path in a thin layer (˜tens of micrometers) of glass media that are two-dimensional too, or unilateral. A cylindrical-lens type spectrometer or waveguide based technology may be utilized for integrating a compact spectrometer into a cellular phone or other portable electronic device. 
     However, in practice, there exist other issues that raise extra concerns in consideration of implementing those two candidate techniques. On one hand, a cylindrical-lens type spectrometer comprises more individual optical elements than its existing counterparts, leading to increases in both manufacturing cost and volume of the integrated package. On the other hand, the manufacturing process of waveguide products is expensive, and there are other technical concerned drawbacks associated with waveguide performance, including high propagation loss, stray light caused by scattering at waveguide boundary, etc. Besides, coupling efficiency of waveguide devices are very susceptible to misalignment at input ends. All of these factors have negative implications when considering whether to apply waveguide based spectrometers in more applications. 
     In general, existing spectrometers have not been an object of miniaturization as has been other technological machines and equipment because of the lack of technology in making it so. Thus, wider applications of spectrometers have not been possible for areas where miniaturization has become increasingly necessary or preferable. These disadvantages of existing spectrometers have been overcome with the present invention, both in the invention itself and the method with which it is made. 
     3. Description of the Related Prior Art, Cellular Phone 
     A cellular phone is a wireless and mobile phone. For the simplicity of discussion in the following sections, the term “cellular phone” and “mobile phone” are used equally in an exchangeable way. The earliest representative of the art of wireless telephone is U.S. Pat. No. 887,357 (1908) to Stubblefield, which discloses an invention applied to “cave radio” telephones between a vehicle to a vehicle, and a vehicle to a station. Since then, radiophones have gone through a long and varied history. 
     The introduction of cells for mobile phone base stations was invented in 1947 by Bell Labs engineers at AT&amp;T. Memo by Douglas H. Ring proposing hexagonal cells, Nov. 11, 1947, Bell Telephone Laborlatries Incorporated. One of representatives for practically implementing cellular phone technology is U.S. Pat. No. 3,663,762 (1972) to Joel, Jr., which discloses an automatic “call handoff” system to allow mobile phones to move through several cell areas during a single conversation without loss of conversation. In general, Motorola is widely considered to be the inventor of the first practical mobile phone for handheld use in a non-vehicle setting. A representative of the art of cellular phone from Motorola is U.S. Pat. No. 3,906,166 (1975) to Cooper et la, a Motorola manager who made the first call on a handheld mobile phone on Apr. 3, 1973. 
     Other representatives of the art of historical significance include: U.S. Pat. No. 4,399,555 (1983) to MacDonald et la, U.S. Pat. No. 5,265,158 (1993) to Tattari, U.S. Pat. No. 5,722,067 (1998) to Fougnies, and U.S. Pat. No. 5,841,856 (1998) to Yoshiyuki Ide. Throughout the period covered by these representatives listed above, cellular phones are commercially introduced to civilians through three generations: 1G (1980˜1990) of an analog signal transmission technique supporting basic voice communication only, 2G (1990˜2000) of digital signal transmission technique, and 3G (2000˜2007) that offers increasing wideband transmission capability. 
     As technologies applied to cellular phone advance, more new features are being incorporated into cellular phones, resulting in new types of cellular phones being introduced with different names, like camera phones, PDA (personal digital assistant) phone or smartphone, and GPS phone, etc. . . . . 
     A camera phone is a mobile phone that has a camera built-in and is coupled with a server-based infrastructure or protocol, which allows the user to instantly share pictures and video with someone that has a device adapted to receive pictures and video. A representative of the art of camera phone is U.S. Pat. No. D405,457 (1999) to Kawashima, which discloses an ornamental design for a digital camera with cellular phone. Other typical representatives of the art of camera phone include: U.S. Pat. No. 6,823,198 (2004) to Kobayashi, U.S. Pat. No. 7,003,318 (2006) to Kota, et al, U.S. Pat. No. 7,117,011 (2006) to Makino, and U.S. Pat. No. 7,228,151 (2007) to Kota, et al, etc. 
     A PDA phone is a PDA and cell phone combination. PDA phones predominantly have data capabilities, multiple data input methods, wireless email functions, security and device management features, organizer functions, USB connection, charging from PC and extensive third party application support, supported by window based operating system. A smartphone on the other hand, is mainly a phone with some PDA phone features like organizer function, data viewing capabilities without editing functions. A representative of the art of PDA phone is U.S. Pat. No. D441,733 (2001) to Do, et al., which discloses a ornamental design for a multiple wireless PDA phone. There exist a few other representatives of the art of PDA phone, including U.S. Pat. No. D498,736 (2004) to Lee, U.S. Pat. No. D502,159 (2005) to Chan, et al., U.S. Pat. No. 7,043,284 (2006) to Tornaghi, U.S. Pat. No. D520,976 (2006) to LaDelfa, and U.S. Pat. No. D526,983 (2006) to Gong, et al. 
     Another representative of the art of cellular phone is: U.S. Pat. No. 6,993,573 (2006) Hunter, which discloses a camera cellular phone that is adapted to image a machine-readable code such as a bar code. It decodes the bar code and sends the bar code data over the Internet to a resolution server that will return an associated URL that will link the camera phone to content on an information server. 
     Another representative of the art of cellular phone is: U.S. Pat. No. 7,164,921 (2007) Owens, et al, which discloses a mobile phone having an internal GPS-receiver. It accommodates any applications in which a wireless communications device such as a cell phone can be caused to report location, with the phone initially in an off condition. 
     From above reviews of related prior art, it can be seen that a cellular phone has become so powerful that it have a numerous advanced capabilities, including: onboard CPU for data processing, LCD for real-time display, USB port for connection, operating system for supporting working environment, and the wireless communication capability to connect to other cellular phones or onto the internet. All of these considerations make a cellular phone an ideal platform for supporting real-time applications associated with a spectrometer. 
     On the other hand, it will not be physically possible to integrate a spectrometer into or with a cellular phone together, unless a spectrometer&#39;s size/volume is significantly reduced with a footprint compatible to that of a cellular phone. Thus, it is the intention of this invention to provide compact spectrometers miniaturized for working with cellular phones or other portable electronic device without scarifying their performances. 
     SUMMARY 
     Definition and Explanation of the Coordinate System 
     A Cartesian co-ordinate system denoted by XYZO is to be referenced in the discussions to follow, where the optical system of a spectrometer resides and light propagates. The co-ordinate system has three axes: X, Y, Z and an origin O. Two important planes are defined here: XOZ represents the horizontal plane, or the sagittal plane; YOZ represents the vertical plane, or the tangential plane. Z represents the propagation direction of light. A beam of light is considered to have a three-dimensional path, if it converges, or diverges, or maintains a finite collimated size in both the tangential and sagittal planes as it propagates in Z direction. A beam of light is considered having a substantially two-dimensional (substantially unilateralized) path, if it converges, or diverges, or maintains a finite collimated size in either the tangential or the sagittal planes, but is confined within a thin layer in or parallel to the other plane, as it propagates in Z direction. 
     The main object of the embodiments is to provide an optical technique that makes the propagation path, either in transparent media or in free space, of the optical beams emitting from a small input aperture/slit of a spectrometer, substantially two-dimensional or substantially unilateralized, enabling physical sizes of any optical elements needed thereafter to construct a spectrometer being reduced significantly in one dimension. As a result, a significant reduction of device volume will be achieved, which is applicable and beneficial to a compact spectrometer, and thus such a compact spectrometer can be integrated into a cellular phone or other portable electronic device. 
     The above description sets forth, rather broadly, a summary of the present invention so that the detailed description that follows may be better understood and contributions of the present invention to the art may be better appreciated. Some of the embodiments to follow of the present invention may not include all of the features or characteristics listed in the above summary. There are, of course, additional features of the invention that will be described below and will form the subject matter of claims. In this respect, before explaining any embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangement of the components set forth in the following description or as illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
     In one aspect, it is an object of the present invention to provide a means to manipulate the propagation properties of the optical beams separately in two independent directions, i.e. in the tangential plane and the sagittal plane, at any intersecting locations between optical beams and optical elements/surfaces inside a spectrometer. The said means calls for usage of optical elements, which have cylindrical or toroidal surfaces with main optical powers only in one direction, i.e. either in the tangential plane or in the sagittal plane. The said optical elements include all types of cylindrical and toroidal lenses; all types of cylindrical and toroidal mirrors; one-dimensional, reflective gratings of planar, or concave cylindrical substrates; herein “all types” represents properties of positive and negative optical power, spherical and aspherical shapes for cross-section. 
     One aspect of the present invention is to provide an entrance aperture of small size at the entrance slit position of spectrometers, where the said entrance aperture can be the core of a single mode fiber, or the core of a multi-mode fiber, or pinholes of diameters similar to those of fibers&#39; cores, or a slit of fiber core widths whose preferred height is less than a few millimeters. The optical outputs of the said entrance aperture may have symmetrical or asymmetrical cone shapes, whose propagation paths are three-dimensional. 
     Another aspect of the present invention is to provide a collimating means to collimate the optical beams emitting from the said entrance aperture in the tangential plane only, making the output beams of the said collimating means anamorphic, which is substantially collimated in the tangential plane, but propagates in divergence freely in the sagittal plane. The said collimating means can be a cylindrical or toroidal lens, or a concave cylindrical or toroidal mirror, or a concave conic cylindrical or toroidal mirror, all of which have main optical power in the tangential plane, but have no or little optical power in the sagittal plane. The said collimating means is properly positioned behind the entrance aperture in the optical train of the spectrometer&#39;s optics, closely enough that its outputs of partially collimated anamorphic beams maintain a small and finite collimated size (no more than a few millimeters) in the tangential plane, whose propagation paths are substantially two-dimensional. 
     Another aspect of the present invention is to provide a dispersing-focusing means, which resides at certain distance behind the collimating means in the optical train of the spectrometer&#39;s optics. The said dispersing-focusing means is capable of performing two tasks in the sagittal plane only: (1) dispersing the input optical beams received from the said collimating means; (2) forming spectral images of the said entrance aperture onto a detector surface. The said dispersing-focusing means can be any one of that of embodiments to be explained below. The outputs of the said dispersing-focusing means remain partially collimated with a small and finite collimated size in the tangential plane, but are focused into spectral images at the said detector surface in the sagittal plane. The said outputs have propagation paths that are substantially two-dimensional. 
     Another aspect of the present invention is to provide a focusing means to focus the optical beams received from the said dispersing-focusing means onto the said detector surface in the tangential plane only. The said focusing means can be a cylindrical or toroidal lens, or a concave cylindrical or toroidal mirror, or a concave conic cylindrical or toroidal mirror, all of which have main optical power in the tangential plane, but have no or little optical power in the sagittal plane. As a result, the output of the said focusing means form a linear spectral image at the said detector surface. The said detector is a linear array of detector pixels residing behind the said focusing means, at the end of the optical train of the spectrometer&#39;s optics. 
     One embodiment of the present invention is directed to a spectrometer comprising: (1) the said entrance aperture, (2) the said collimating means, the said dispersing-focusing means, (6) the said focusing means and (7) the said detector, where the said dispersing-focusing means is a reflectance sub-system comprising: (3) a cylindrical/toroidal mirror for collimating in the sagittal plane, (4) a reflective grating for dispersing in the sagittal plane and (5) a cylindrical/toroidal mirror for focusing in the sagittal plane. Optical means from (2) to (6) can be fabricated by a thin piece of monolithic transparent material. The propagation paths within the spectrometer from (1) to (7) are substantially two-dimensional. 
     Another embodiment of the present invention is directed to a spectrometer with Fastie-Ebert configuration comprising: (1) the said entrance aperture, (2) the said collimating means, the said dispersing-focusing means, (5) the said focusing means and (6) the said detector, where the said dispersing-focusing means is a reflectance sub-system comprising: (3) a cylindrical/toroidal mirror for both collimating and focusing in the sagittal plane, and (4) a reflective grating for dispersing in the sagittal plane. Optical means from (2) to (5) can be fabricated by a thin piece of monolithic transparent material. The propagation paths within the spectrometer from (1) to (6) are substantially two-dimensional. 
     Another embodiment of the present invention is directed to a spectrometer with Czerny-Turner configuration comprising: (1) the said entrance aperture, (2) the said collimating means, the said dispersing-focusing means, (6) the said focusing means and (7) the said detector, where the said dispersing-focusing means is a reflectance sub-system comprising: (3) a cylindrical/toroidal mirror for collimating in the sagittal plane, (4) a reflective grating for dispersing in the sagittal plane and (5) a cylindrical/toroidal mirror for focusing in the sagittal plane. Optical means from (2) to (6) can be fabricated by a thin piece of monolithic transparent material. The propagation paths within the spectrometer from (1) to (7) are substantially two-dimensional. 
     Another embodiment of the present invention is directed to a spectrometer comprising (1) the said entrance aperture, (2) the said collimating means, the said dispersing-focusing means, (5) the said focusing means and (6) the said detector, wherein the said dispersing-focusing means is a hybrid sub-system comprising: (3) a cylindrical/toroidal lens for collimating and focusing in the sagittal plane, and (4) a reflective grating for dispersing in the sagittal plane. The propagation paths within the spectrometer from (1) to (6) are substantially two-dimensional. 
     Another embodiment of the present invention is directed to a spectrometer comprising: (1) the said entrance aperture, (2) the said collimating means, (3) the said dispersing-focusing means, (4) the said focusing means and (5) the said detector, where the said dispersing-focusing means is a concave (cylindrical or toroidal) reflective grating for dispersing and focusing in the sagittal plane. Optical means from (2) to (4) can be fabricated by a thin piece of monolithic transparent material. The propagation paths within the spectrometer from (1) to (5) are substantially two-dimensional. 
     One important aspect of the present invention is directed to build a spectrometer based on one of above embodiments or their modified configurations, in which the said collimating means and the said focusing means fulfill tasks of (1) generating images of the said entrance aperture onto the said detector surface in the tangential plane, and (2) making the propagation paths of optical beams within the spectrometer substantially two-dimensional. Meanwhile, the said dispersing-focusing means of the said spectrometer fulfills tasks of (i) dispersing the received optical beams into spectra in the sagittal plane, and (ii) generating spectral images of the said entrance aperture onto the said detector surface in the sagittal plane. In this way, significant improvements are achieved in two aspect: (a) sizes and dimensions of all optical elements used inside the said spectrometer are significantly reduced in Y direction, i.e. in the vertical plane or the tangential plane; as a result, the instrument/device volume is significantly reduce; (b) optical aberration of astigmatism and curvature of spectral images are well compensated. 
     It is an object of the present invention to physically integrate a compact spectrometer, preferably based on one of those embodiments specified above, into a cellular phone, or other portable electronic device, to form a standalone system for spectroscopic applications. Such a combined system will take optical inputs, through an optical fiber or direct coupling optics via the entrance aperture, into its built-in spectrometer for spectral measurements. The cellular phone or other portable electronic device is able to process the data, or display measurement results, or send the measurement data to a remote receiver via wireless communication. 
     It is another object of the present invention to physically attach a compact spectrometer, preferably based on one of those embodiments specified above, to a cellular phone to form a standalone system for spectroscopic applications. The said spectrometer is electronically linked with the cellular phone or other portable electronic device via USB connections. Such a combined system will take optical inputs, through an optical fiber or direct coupling optics via the entrance aperture, into the attached spectrometer for spectral measurements. The cellular phone is able to process the data, or display measurement results, or send the measurement data to a remote receiver via wireless communication. 
     It is another object of the present invention to physically integrate or attach a compact spectrometer, which is built with a monolithic substrate based on waveguide technology, to a cellular phone or other electronic device to form a standalone system for spectroscopic applications. The said spectrometer comprise: (1) the entrance aperture, (2) the optical coupling means, (3) the said dispersing-focusing means, and (4) the said detector, wherein the said dispersing-focusing means is fabricated on a thin piece of monolithic transparent waveguide substrate, whose optics comprise one of the following approaches: optics of a concave mirror, reflective grating and another concave mirror; optics of Czerny-Turner configuration; optics of Fastie-Ebert configuration; or optics of a concave reflective grating. The propagation paths of (3) within the spectrometer are substantially two-dimensional. Using the combined system, the cellular phone or other portable electronic device is able to process the data, or display measurement results, or send the measurement data to a remote receiver via wireless communication. 
     It is another objective to use the said standalone system mentioned above, i.e. “spectrometer phone”, with a laser as a Raman spectrometer system. Such a portable Raman system can be used to identify materials in many applications. One example is that it makes it possible for civilians to fulfill daily routine health monitoring easily, for example, non-invasive blood glucose monitoring by diabetes patients at home, or non-invasive blood cholesterols&#39; monitoring by a user. 
     It is another objective to use the said standalone system mentioned above, i.e. “spectrometer phone”, with a NIR source as a NIR spectrometer system. Such a portable NIR system can be used to identify materials in many applications. One example is that it makes it possible for civilians to fulfill daily routine health monitoring easily, for example, non-invasive blood glucose monitoring by diabetes patients at home, or non-invasive blood cholesterols&#39; monitoring by a user. 
     It is another objective to use the said standalone system mentioned above, i.e. “spectrometer phone”, to measure colors or spectra of input light signals over at least one of the spectral bands: ultra-violet, visible, near infrared and infrared. The said input light signals fall into at least one kind of electro-magnetic waves: radiating from a source, reflected from an object or materials, transmitting through an object or materials, excited fluorescent radiation by a UV light or a laser from an object or materials, or excited Raman radiation by a laser from an object or materials. 
     The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures and the detailed description, which follow more particularly, exemplify these embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows perspective views of a compact spectrometer comprising a concave grating only, where  FIG. 1(   a ) represents a prior art, and  FIG. 1(   b ), ( c ) and ( d ) represent three preferred embodiments of the same spectrometer based on the present invention. 
         FIG. 2  shows perspective views of a compact spectrometer comprising a lens and a reflective grating, where  FIG. 2(   a ) represents a prior art, and  FIG. 2(   b ) represents one embodiment of the same spectrometer based on the present invention. 
         FIG. 3  shows perspective views of a mirror spectrometer of Czerny-Turner or Fastie-Ebert configuration, where  FIG. 3(   a ) represents a prior art, and  FIG. 3(   b ) represents one embodiment of the same spectrometer based on the present invention. 
         FIG. 4  shows perspective views of a mirror spectrometer of crossed Czerny-Turner configuration, where  FIG. 4(   a ) represents a prior art, and  FIG. 4(   b ) represents one embodiment of the same spectrometer based on the present invention. 
         FIG. 5(   a ) and  FIG. 5(   b ) are two embodiments of compact spectrometers based on waveguide technology, which represent qualified candidates of compact spectrometers capable of being integrated into a spectrometer in the present invention. 
         FIG. 6(   a ) shows an embodiment of a cellular phone integrated with a built-in miniature spectrometer in a process of real-time spectroscopic measurements, and  FIG. 6(   b ) shows an embodiment of a cellular phone integrated with a built-in miniature spectrometer in a process of Raman spectroscopic measurements in medical application. 
         FIG. 7(   a ) represents a cellular phone capable of functioning as a platform,  FIG. 7(   b ) represents a compact spectrometer with a thin package,  FIG. 7(   c ) shows a cellular phone attached with such a compact spectrometer in a process of real-time spectroscopic measurements, and  FIG. 7(   d ) shows a cellular phone attached with such a compact spectrometer in a process of Raman spectroscopic measurements in medical application. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Referring now to the drawings, to the following detailed description, and to the incorporated materials, detailed information about the invention is provided including the description of specific embodiments. The detailed description serves to explain the principles of the invention. The invention is susceptible to modifications and alternative forms. The invention is not limited to the particular forms and embodiments disclosed. The invention covers all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the claims. 
     Referring to  FIG. 1(   a ), a prior art of a compact spectrometer is illustrated in ray-trace form, which is designated by the general reference numeral  100 . Its optics comprises an entrance aperture  102  that is the core of the optical fiber  101  for input signal delivery, and a concave diffraction grating  106 . For the spectrometer  100 , the input light  105  emits from the entrance aperture  102  and propagates in divergence towards the concave grating  106 , which disperses, in a reflective manner, the divergent light  105  and focuses it into the convergent light  107  to form spectral images  110  on the detector  111 . As shown in  FIG. 1(   a ), the propagation paths for the divergent light  105  and the convergent light  107  are all three-dimensional. The single key optical element within the spectrometer  100 , i.e. the concave grating  106 , must have finite working apertures large enough to accept and manipulate the light  105  and  107  without truncating them at any locations. As a result, the overall dimensional volume necessitated to construct the spectrometer  100  is three-dimensional, which is too large for being integrated into a cellular phone package, or other portable electronic device package, and very difficult or impossible to be reduced without sacrificing its performance characteristics. 
     In  FIG. 1(   b ), one preferred embodiment of the same compact spectrometer as shown in  FIG. 1(   a ) in ray-trace form is illustrated based on the present invention, which is designated by the general reference numeral  140 . The spectrometer  140  is constructed by combining its three key optical elements together with a single piece of monolithic transparent carrier. Its optics comprises an entrance aperture  142  that is the core of the optical fiber  141  for input signal delivery, a first cylindrical surface  144 , a concave cylindrical grating  146 , and a second cylindrical surface  148 . For the spectrometer  140 , the input light  143  emits from the entrance aperture  142  and propagates in divergence over a very short distance, then is intercepted by the first cylindrical surface  144 , which collimates the divergent light  143  only in the tangential plane, converting it into a partially collimated light, i.e. the anamorphic light  145 , which is collimated in the tangential plane, but remains divergent in the sagittal plane. The light  145  propagates in the transparent medium and is intercepted by the concave cylindrical grating  146 , which disperses, in a reflective manner, the light  145  and focuses it only in the sagittal plane into the anamorphic light  147 , which remains collimated in the tangential plane, but is dispersed and convergent in the sagittal plane. Upon being intercepted by the second cylindrical surface  148 , the light  147  is focused in the tangential plane into the fully convergent light  149  to form spectral images  150  on the detector  151 . As shown in  FIG. 1(   b ), the propagation paths for the anamorphic light  145  and the anamorphic light  147  are all substantially two-dimensional. The three key optical surfaces within the spectrometer  140 , i.e. the first cylindrical surface  144 , the concave cylindrical grating  146  and the second cylindrical surface  148 , must have finite working aperture dimensions large enough only in the sagittal direction (horizontal), but very small aperture dimensions needed in the tangential direction (vertical), in order to accept and manipulate light  143 ,  145 ,  147  and  149  without truncating them at any locations. In practice, the tangential dimensions (vertical) of those key optical surfaces needed become a small fractions of their original values in the same prior art, for example, around ⅕˜ 1/10 (i.e., an approximate reduction in size of 80% to 90% may be achieved) or even better. As a result, the overall dimensional volume necessitated to construct the spectrometer  140  is substantially two-dimensional, or substantially unilateral, which is significantly reduced compared with that of its prior art spectrometer without sacrificing its performance characteristics. Thus it is possible, based on the present invention, to easily construct a spectrometer fabricated with a single piece of thin transparent carrier, which is robust and of very compact volume, and can be integrated into a cellular phone package, or other portable electronic device, to form a complete standalone spectroscopic system for many application, for example, real-time spectroscopic measurements. 
     In  FIG. 1(   c ), another embodiment of the same compact spectrometer as shown in  FIG. 1(   b ) in ray-trace form is illustrated based on the present invention, which is designated by the general reference numeral  160 . It only differentiates from  140  of  FIG. 1(   b ) by its input coupling optics, where the illuminating light  161  transmits through the object or material under test  162 , and is then focused by the input coupling lens  163  onto the input aperture, here a slit  164 . After propagating through the slit  164 , the input light  165  enters the spectrometer  160 , which forms spectral images  169  on the detector  170 . 
     In  FIG. 1(   d ), another embodiment of the same compact spectrometer as shown in  FIG. 1(   a ) and ( b ) in ray-trace form is illustrated based on the present invention, which is designated by the general reference numeral  180 . It is similar to that of the embodiment of  FIG. 1(   b ) with even simpler structure: the two cylindrical surfaces  144  and  148  of spectrometer  140  in  FIG. 1(   b ) are combined into a single cylindrical surface  184  of spectrometer  180  in  FIG. 1(   d ). Similarly, this spectrometer is also robust and of very compact volume, and can be integrated into a cellular phone package, or other portable electronic device package, to form a complete standalone spectroscopic system for many application, for example, real-time spectroscopic measurements. 
     Next referring to  FIG. 2(   a ), a prior art of a compact spectrometer is illustrated in ray-trace form, which is designated by the general reference numeral  200 . Its optics comprises an entrance aperture  204  that is the core of the optical fiber  202  for input signal delivery, a lens  208  for both collimating and focusing, and a reflective diffraction grating  212 . For the spectrometer  200 , the input light  206  emits from the entrance aperture  204  and propagates in divergence towards the lens  208 , which collimates the divergent light  206  into the collimated light  210 . The collimated light  210  propagates and is incident upon the grating  212 , which disperses, in a reflective manner, the light  210  into the dispersive collimated light  214 , and then the same lens  208  focuses the light  214  into the convergent light  218  to form spectral images  220  on the detector  222 . As shown in  FIG. 2(   a ), the propagation paths for the divergent light  206 , the collimated light  210 , the dispersive light  214 , and the convergent light  218  are all three-dimensional. The two key optical elements within the spectrometer  200 , i.e. the lens  208  and the grating  212 , must have finite working apertures large enough to accept and manipulate the light  206 ,  210 ,  214  and  218  without truncating them at any locations. As a result, the overall dimensional volume necessitated to construct the spectrometer  200  is three-dimensional, which is too large for being integrated into a cellular phone package, or other portable electronic device, and very difficult or impossible to be reduced without sacrificing its performance characteristics. 
     In  FIG. 2(   b ), one embodiment of the same compact spectrometer as shown in  FIG. 2(   a ) is illustrated in ray-trace form based on the present invention, which is designated by the general reference numeral  280 . The spectrometer  280  is constructed by combining its three key optical surfaces necessitated to build a compact spectrometer together with a single piece of monolithic transparent carrier. Its optics comprises an entrance aperture  283  that is the core of the optical fiber  282  for input signal delivery, a first cylindrical surface  286 , a second cylindrical surface  288 , a reflective diffraction grating  291  and a third cylindrical surface  295 . For the spectrometer  280 , the input light  284  emits from the entrance aperture  283  and propagates in divergence over a very short distance, then is intercepted by the first cylindrical surface  286 , which collimates the divergent light  284  only in the tangential plane, converting it into a partially collimated light, i.e. the anamorphic light  287 , which is collimated in the tangential plane, but remains divergent in the sagittal plane. The light  287  propagates and is intercepted by the second cylindrical surface  288 , which collimates it only in the sagittal plane, converting it into the fully collimated light  290 . The light  290  continues to propagate and is incident upon the grating  291 , which disperses, in a reflective manner, the light  290  into dispersive collimated light  292 . Upon being intercepted by the same cylindrical surface  288 , the light  292  is partially focused in the sagittal plane into the light  294 , which is further partially focused by the third cylindrical surface  295  in the tangential plane into the fully convergent light  296  to form spectral images  298  on the detector  299 . As shown in  FIG. 2(   b ), the propagation paths for the anamorphic light  287 , collimated light  290 , dispersive light  292 , and the anamorphic light  294  are all substantially two-dimensional. The four key optical elements/surfaces within the spectrometer  280 , i.e. the first cylindrical surface  286 , the second cylindrical surface  288 , the grating  291  and the third cylindrical surface  295 , must have finite working aperture dimensions large enough only in the sagittal direction (horizontal), but very small aperture dimensions needed in the tangential direction (vertical), in order to accept and manipulate light  284 ,  287 ,  290 ,  292 ,  294  and  296  without truncating them at any locations. In practice, the tangential dimensions (vertical) of those key optical surfaces needed become a small fractions of their original values in the same prior art, for example, around ⅕˜ 1/10 (i.e., an approximate reduction in size of 80% to 90% may be achieved) or even better. As a result, the overall dimensional volume necessitated to construct the spectrometer  280  is two-dimensional, or unilateral, which is significantly reduced compared with that of its prior art spectrometer without sacrificing its performance characteristics. Thus it is possible, based on the present invention, to easily construct a spectrometer fabricated with a single piece of thin transparent carrier, which is robust and of very compact volume, and can be integrated into a cellular phone package, or other portable electronic device package, to form a complete standalone spectroscopic system for many application, for example, real-time spectroscopic measurements. 
     Next, referring to  FIG. 3(   a ), a prior art of a mirror spectrometer of Czerny-Turner geometry is illustrated in ray-trace form, which is designated by the general reference numeral  300 . Its optics comprises an entrance aperture  304  that is the core of the optical fiber  302  for input signal delivery, a collimating mirror  308 , a reflective diffraction grating  312  and a focusing mirror  316  (its optics becomes a Fastie-Ebert geometry when mirror  308  and mirror  316  are two areas of the same single mirror). For the spectrometer  300 , the input light  306  emits from the entrance aperture  304  and propagates in divergence towards the collimating mirror  308 , which collimates the divergent light  306  into the collimated light  310 . The collimated light  310  propagates and is incident upon the grating  312 , which disperses, in a reflective manner, the light  310  into the dispersive collimated light  314 , and then the focusing mirror  316  focuses the light  314  into the convergent light  318  to form spectral images  320  on the detector  322 . As shown in  FIG. 3(   a ), the propagation paths for the divergent light  306 , the collimated light  310 , the dispersive light  314 , and the convergent light  318  are all three-dimensional. The three key optical elements within the spectrometer  300 , i.e. the collimating mirror  308 , the grating  312  and the focusing mirror  316 , must have finite working apertures large enough to accept and manipulate the light  306 ,  310 ,  314  and  318  without truncating them at any locations. As a result, the overall dimensional volume necessitated to construct the spectrometer  300  is three-dimensional, which is too large for being integrated into a cellular phone package, and very difficult or impossible to be reduced without sacrificing its performance characteristics. 
     In  FIG. 3(   b ), one embodiment of the same mirror spectrometer of Czerny-Turner geometry as shown in  FIG. 3(   a ) is illustrated in ray-trace form based on the present invention, which is designated by the general reference numeral  360 . The spectrometer  360  is constructed by combining the five key optical surfaces necessitated to build a compact spectrometer together with a single piece of monolithic transparent carrier. Its optics comprises an entrance aperture  363  that is the core of the optical fiber  362  for input signal delivery, a first cylindrical surface  365 , a first cylindrical mirror  367 , a reflective diffraction grating  370 , a second cylindrical mirror  373  and a second cylindrical surface  376 . For the spectrometer  360 , the input light  364  emits from the entrance aperture  363  and propagates in divergence over a very short distance, then is intercepted by the first cylindrical surface  365 , which collimates the divergent light  364  only in the tangential plane, converting it into a partially collimated light, i.e. the anamorphic light  366 , which is collimated in the tangential plane, but remains divergent in the sagittal plane. The light  366  propagates and is intercepted by the first cylindrical mirror  367 , which collimates it only in the sagittal plane, converting it into the fully collimated light  368 . The light  368  continues to propagate and is incident upon the grating  370 , which disperses, in a reflective manner, the light  368  into the dispersive collimated light  372 . Upon being intercepted by the second cylindrical mirror  373 , the light  372  is partially focused in the sagittal plane into the light  374 , which is further partially focused by the second cylindrical surface  376  in the tangential plane into the fully convergent light  377  to form spectral images  378  on the detector  379 . As shown in  FIG. 3(   b ), the propagation paths for the anamorphic light  366 , the collimated light  368 , the dispersive light  372 , and the anamorphic light  374  are all substantially two-dimensional. The five key optical surfaces within the spectrometer  360 , i.e. the first cylindrical surface  365 , the first cylindrical mirror  367 , the grating  370 , the second cylindrical mirror  373  and the second cylindrical surface  376 , must have finite working aperture dimensions large enough only in the sagittal direction (horizontal), but very small aperture dimensions needed in the tangential direction (vertical), in order to accept and manipulate light  364 ,  366 ,  368 ,  372 ,  374  and  377  without truncating them at any locations. In practice, the tangential dimensions (vertical) of those key optical surfaces needed become a small fractions of their original values in the same prior art, for example, around ⅕˜ 1/10 (i.e., an approximate reduction in size of 80% to 90% may be achieved) or even better. As a result, the overall dimensional volume necessitated to construct the spectrometer  360  is substantially two-dimensional, or substantially unilateral, which is significantly reduced compared with that of its prior art spectrometer without sacrificing its performance characteristics. Thus it is possible, based on the present invention, to easily construct a spectrometer fabricated with a single piece of thin transparent carrier, which is robust and of very compact volume, and can be integrated into a cellular phone package, or other portable electronic device package, to form a complete standalone spectroscopic system for many application, for example, real-time spectroscopic measurements. 
     Next, referring to  FIG. 4(   a ), another prior art of a mirror spectrometer of crossed Czerny-Turner geometry is illustrated in ray-trace form, which is designated by the general reference numeral  400 . The spectrometer  400  is modified from the spectrometer  300  in  FIG. 3(   a ), where the incident beam and the reflected beam from the diffraction grating cross. Its optics comprises an entrance aperture  404  that is the core of the optical fiber  402  for input signal delivery, a collimating mirror  408 , a reflective diffraction grating  412  and a focusing mirror  416 . For the spectrometer  400 , the input light  406  emits from the entrance aperture  404  and propagates in divergence towards the collimating mirror  408 , which collimates the divergent light  406  into the collimated light  410 . The collimated light  410  propagates and is incident upon the grating  412 , which disperses, in a reflective manner, the light  410  into the dispersive collimated light  414 , and then the focusing mirror  416  focuses the light  414  into the convergent light  418  to form spectral images  420  on the detector  422 . As shown in  FIG. 4(   a ), the propagation paths for the divergent light  406 , the collimated light  410 , the dispersive light  414 , and the convergent light  418  are all three-dimensional. The three key optical elements within the spectrometer  400 , i.e. the collimating mirror  408 , the grating  412  and the focusing mirror  416 , must have finite working apertures large enough to accept and manipulate the light  406 ,  410 ,  414  and  418  without truncating them at any locations. As a result, the overall dimensional volume necessitated to construct the spectrometer  400  is three-dimensional, which is too large for being integrated into a cellular phone package, and very difficult or impossible to be reduced without sacrificing its performance characteristics. 
     In  FIG. 4(   b ), one embodiment of the same mirror spectrometer of crossed Czerny-Turner geometry as shown in  FIG. 4(   a ) is illustrated in ray-trace form based on the present invention, which is designated by the general reference numeral  480 . The spectrometer  480  is constructed by combining its five key optical surfaces necessitated to build a compact spectrometer together with a single piece of monolithic transparent carrier. Its optics comprises an entrance aperture  483  that is the core of the optical fiber  482  for input signal delivery, a first cylindrical surface  486 , a first cylindrical mirror  488 , a reflective diffraction grating  491 , a second cylindrical mirror  494  and a second cylindrical surface  496 . For the spectrometer  480 , the input light  484  emits from the entrance aperture  483  and propagates in divergence over a very short distance, then is intercepted by the first cylindrical surface  486 , which collimates the divergent light  484  only in the tangential plane, converting it into a partially collimated light, i.e. the anamorphic light  487 , which is collimated in the tangential plane, but remains divergent in the sagittal plane. The light  487  propagates and is intercepted by the first cylindrical mirror  488 , which collimates it only in the sagittal plane, converting it into the fully collimated light  490 . The light  490  continues to propagate and is incident upon the grating  491 , which disperses, in a reflective manner, the light  490  into the dispersive collimated light  492 . Upon being intercepted by the second cylindrical mirror  494 , the light  492  is partially focused in the sagittal plane into the light  495 , which is further partially focused by the second cylindrical surface  496  in the tangential plane into the fully convergent light  497  to form spectral images  498  on the detector  499 . As shown in  FIG. 4(   b ), the propagation paths for the anamorphic light  487 , the collimated light  490 , the dispersive light  492 , and the anamorphic light  495  are all substantially two-dimensional. The five key optical surfaces within the spectrometer  480 , i.e. the first cylindrical surface  486 , the first cylindrical mirror  488 , the grating  491 , the second cylindrical mirror  494  and the second cylindrical surface  496 , must have finite working aperture dimensions large enough only in the sagittal direction (horizontal), but very small aperture dimensions needed in the tangential direction (vertical), in order to accept and manipulate light  484 ,  487 ,  490 ,  492 ,  495  and  497  without truncating them at any locations. In practice, the tangential dimensions (vertical) of those key optical surfaces needed become a small fractions of their original values in the same prior art, for example, around ⅕˜ 1/10 (i.e., an approximate reduction in size of 80% to 90% may be achieved) or even better. As a result, the overall dimensional volume necessitated to construct the spectrometer  480  is two-dimensional, or unilateral, which is significantly reduced compared with that of its prior art spectrometer without sacrificing its performance characteristics. Thus it is possible, based on the present invention, to easily construct a spectrometer fabricated with a single piece of thin transparent carrier, which is robust and of very compact volume, and can be integrated into a cellular phone package to form a complete standalone spectroscopic system for many application, for example, real-time spectroscopic measurements. 
     Next, referring to  FIG. 5(   a ), where one embodiment of the candidate spectrometer based on waveguide technology is illustrated in the present invention, which is designated by the general reference numeral  500 . It is constructed in a “sandwich” structure of three layers of glass: upper layer  502 , middle layer  504  (very thin thickness of a ten to tens of microns) and lower layer  506 , where  502  and  506  have refractive index lower than that of  504 , all of which are combined together to form a single piece of monolithic transparent carrier. Its optics comprises an entrance aperture  514  that is the core of the optical fiber  512  (or a pinhole here) for input signal delivery, an input coupling lens  518 , an upper waveguide interface between layer  502  and layer  504 , a lower waveguide interface between layer  504  and layer  506 , and a cylindrical reflective diffraction grating  526 . For the spectrometer  500 , the input light  516  emits from the entrance aperture  514  and propagates in divergence over a very short distance, then is intercepted by the coupling lens  518 , which converts the divergent light  516  into the convergent light  520  and forms a 1:1 image of the entrance aperture  514  onto the input surface  522 . After being coupled into the middle layer  504 , the light  520  becomes an anamorphic divergent light  524 , because its propagation path is confined in the tangential plane (vertical) by the total internal reflections occurring at the upper and lower waveguide interfaces, but unconfined divergent in the sagittal plane (horizontal). The light  524  continues to propagate and is incident upon the cylindrical grating  526 , which disperses, in a reflective manner, the light  524  into the dispersive focused light  528 , which forms the spectral images  530  upon arriving at the exiting and the detector surface  532 , where the spectral images  530  have plural images laterally spread representing different wavelengths; vertically, each image point has a size equal to the thickness of the middle layer  504 . As shown in  FIG. 5(   a ), the propagation paths for the anamorphic light  524 , the dispersive anamorphic light  528  are all substantially two-dimensional. The associated waveguide structure must have finite working aperture dimensions large enough only in the sagittal direction (horizontal), but very small aperture dimensions needed in the tangential direction (vertical), in order to accept and manipulate light  520 ,  524  and  528  to form spectral images. In practice, a few millimeters as the total tangential dimensions (vertical) of the “sandwich structure”, i.e. the three optical glass layers, will be enough to provide a waveguide carrier body of the desired strength. As a result, the overall dimensional volume necessitated to construct the spectrometer  500  is substantially two-dimensional, or substantially unilateral. Thus it is possible, based on the present invention, to easily construct such a spectrometer fabricated with a waveguide substrate, which is robust and of very compact volume, and can be integrated into a cellular phone package, other portable electronic device package, to form a complete standalone spectroscopic system for many application, for example, real-time spectroscopic measurements. 
       FIG. 5(   b ) represents another embodiment similar to that of  FIG. 5(   a ), where a spectrometer  550  is built with a waveguide structure of two layers: a thin middle layer  554  of higher refractive index and a thick lower layer  556  of lower refractive index. Here an upper waveguide interface exists between the air and layer  554 , and a lower waveguide interface exists between layer  554  and layer  556 . Its optics works in the same way as that of  FIG. 5(   a ) and its propagation path is confined vertically in the tangential plane by the total internal reflections. This embodiment differentiates itself from that of  FIG. 5(   a ) by the waveguide structure, herein the thin layer  554  is the light propagation layer fabricated by an approach different from that used for the spectrometer  500  in  FIG. 5(   a ). The layer  556  is the main structure supporting substrate, and as long as it is strong enough for providing the desired strength, then it is possible, based on the present invention, to easily construct such a spectrometer fabricated with a waveguide substrate, which is robust and of very compact volume, and can be integrated into a cellular phone package, or other portable electronic device package, to form a complete standalone spectroscopic system for many application, for example, real-time spectroscopic measurements. 
     Next, referring to  FIG. 6(   a ), an embodiment of a cellular phone integrated with a built-in miniature spectrometer is illustrated, which is designated by the general reference numeral  600 . As a complete “spectrometer phone”, it may have at least the following working modes: (1) wireless communication mode for making phone calls, browsing internet, sending/retrieving e-mails, transferring data, etc., (2) camera mode (if a digital camera is built in) for taking pictures, (3) PDA mode for functions of a computer, and (4) spectrometer mode for spectroscopic measurement. When the device is switched to the spectrometer mode, it is able to function as a truly standalone system for real-time spectroscopic measurements. In a typical such measurement, for example, the illuminating light  602  is shone on the sample  604 , which reflects or radiates excited light  606  (depending on the nature of the incident light  602 ). The light  606  can be reflected light, or transmitted light, or excited fluorescent or Raman radiations in UV, or visible, or infrared spectral range (depending on applications). The fiber head  608  collects a portion of the light  606  and its focusing optics couples the input optical signals into the optical fiber  610 . The fiber  610  is connected with the device  614  through the fiber connector  612 , delivering input optical signals into the built-in spectrometer. Properly pressing buttons  616  to input different functioning commands by the operator, tasks of measurements like taking a spectrum, saving a spectrum, displaying a spectrum on the LCD window  618 , etc., can be fulfilled accordingly. This “spectrometer phone” is a compact, standalone device and provides convenience of usage: the operator can hold the device  614  with one hand and use the other hand to handle and point the fiber head  608  to collect input optical signals  606 . At any time after a spectrum is measured, it can be sent out in wireless communication to a remote station or another cellular phone user to share the measurement results right away, allowing instant data analyzing or information processing to be fulfilled, which is very critical in a wide range of applications. 
     Referring to  FIG. 6(   b ), another embodiment of the same “spectrometer phone” used in a medical application is illustrated, which is designated by the general reference numeral  650 . This health care monitoring system is used as a Raman spectrometer and can be used at a civilian&#39;s home. It comprises: the laser  654 , the Raman fiber cable  658  and the “spectrometer phone”  672 . The laser  654  can be a compact laser like a laser diode, which can be integrated in the “spectrometer phone”  672 . The Raman cable  658  is a commercially available product from InPhotonics based on U.S. Pat. No. 5,122,127. When the phone  672  is switched to the spectrometer mode, it is able to function as a truly standalone system for health monitoring measurements. In a non-invasive blood glucose measurement, for example, the excitation light comes from the laser  654 , which is delivered through the laser fiber channel  656  and the main fiber cable  658  to the optical head  660 , where the output laser  664  is focused on the sample  652  through the lens in tube  662 . Herein the sample  652  is a patient&#39;s ear and the laser spot  664  is focused on the earlobe, where more blood may generate stronger Raman signals. As the result of laser excitation, Raman signal light  666  from blood is excited. The lens in tube  662  collects a portion of the light  666 , which is re-directed by the built-in dichroic filter inside optical head  660  and coupled into the signal channel inside cable  658 , which is branched to signal fiber  668 . The fiber  668  is connected with the device  672  through the fiber connector  670 , delivering input Raman signals into the built-in spectrometer. Properly pressing buttons  674  to input different functioning commands by the operator, tasks of measurements like taking a spectrum, processing the spectrum, saving a spectrum, displaying a spectrum on the LCD window  676 , etc., can be fulfilled accordingly. This “spectrometer phone” based Raman system is a compact, standalone device and provides convenience of usage for diabetes patients to carry out daily routine measurements of the blood glucose at home in a non-invasive manner. It offers significant advantages in reducing the cost and health risk, compared with other methods for fulfilling the same task. It can also be used to monitor other blood components like cholesterol in a non-invasive manner. 
     Next, referring to  FIG. 7(   a ), a cellular phone at its slide out position with its keyboard exposed is illustrated, which is designated by the general reference numeral  700 . As a “camera PDA phone” supporting multi functions, it may have at least the following working modes: (1) wireless communication mode for making phone calls, browsing internet, sending/retrieving e-mails, transferring data, etc., (2) camera mode for taking pictures, and (3) PDA mode for functions of a computer. It comprises: the top portion  702  which has LCD display window  704 , function buttons  706 , and bottom portion  708  which has keyboard  710  and I/O port  712  including an USB port. 
     Referring to  FIG. 7(   b ), a compact spectrometer in the package based on the present invention is illustrated, which is designated by the general reference numeral  720 . As a complete independent subsystem, its main body  722  has two ports to communicate with outside world: the USB port  724  where a USB cable  726  is connected, and fiber connection port  728  for optical inputs. The mechanical package of this compact spectrometer is very thin and has the same footprint of that of the “PDA phone”  700  shown in  FIG. 7(   a ). There are three stripes of Velcro tapes  730  on the top surface of its main body  722  for attaching with the cellular phone  700 . 
     Referring to  FIG. 7(   c ), an embodiment of the same cellular phone  700  attached with the same compact spectrometer  720  by Velcro tapes is illustrated, which is designated by the general reference numeral  740 . As a combined standalone system of “spectrometer plus phone”, it has all those three working modes listed above plus a new mode: spectrometer mode for spectroscopic measurement, which is implemented by entering into PDA mode for functions of a computer and running an associated software to allow the phone  700  and the spectrometer  720  to communicate with each other via USB connection. USB connection is easily fulfilled via cable  762  connecting USB port  764  and USB port  766  at each end. When the device is switched to the spectrometer mode, the spectrometer  720  gets electrical power via USB connection from the phone  700 , and will send measured electronic signals back to the phone  700  via USB connection as well. In a typical such measurement, for example, the incident light  742  is shone on the sample  744 , which reflects or radiates excited light  746  (depending on the nature of the incident light  742 ). The fiber head  748  collects a portion of the light  746  and its focusing optics couples the input optical signals into the optical fiber  750 . The fiber  750  is connected with the spectrometer  754  through the fiber connector  752 , delivering input optical signals into the spectrometer. Properly pressing buttons  756  and keyboard  758  to input different functioning commands by the operator, tasks of measurements like taking a spectrum, saving a spectrum, displaying a spectrum on the LCD window  760 , etc., can be fulfilled accordingly. This “spectrometer plus phone” becomes a compact, standalone device and provides convenience of usage: the operator can hold the unit  740  with one hand and use the other hand to handle and point the fiber head  748  to collect input optical signals  746 . At any time after a spectrum is measured, it can be sent out in wireless communication to a remote station or another cellular phone user to share the measurement results right away, allowing instant data analyzing or information processing to be fulfilled, which is very critical in a wide range of applications. 
     Referring to  FIG. 7(   d ), another embodiment of the same “spectrometer plus phone” shown in  FIG. 7(   c ) used in a medical application is illustrated, which is designated by the general reference numeral  770 . It comprises: the laser  776 , the Raman fiber cable  778 , the spectrometer  774  and the phone  772 . The laser  776  can be a compact laser like a laser diode, which can be integrated in the spectrometer  774 . The Raman cable  778  is a commercially available product from InPhotonics based on U.S. Pat. No. 5,122,127. This Raman spectrometer is used as a health care monitoring system and can be used at a civilian&#39;s home for non-invasive glucose monitoring in the same way as described in  FIG. 6(   b ). This “spectrometer plus phone” based Raman system is a compact, standalone device and provides convenience of usage for diabetes patients to carry out daily routine measurements of the blood glucose at home in a non-invasive manner. It offers significant advantages in reducing the cost and health risk, compared with other methods for fulfilling the same task. It can also be used to monitor other blood components like cholesterol in a non-invasive manner.