US2913584A - Microspectrographic system - Google Patents

Description

ums J. M. DILL MICROSPECTROGRAPHIC SYSTEM Nov. "17, 1959 Filed April 18, 1955 TOHICW 4MPL/F.

INVENTOR.

JIM/5 M 0/41.

United States Patent MICROSPECTROGRAPHIC. SYSTEM James M. Dill, Los Angeles, Calif., assignor to Leo T. Ratigan, Glendale, Calif.

Application April '18, 1955, Serial No. 501,768 22 Claims. 01. 250-205 f tion spectrum of a specimen, generally involves the im pingement on the specimen of a beam of radiant energy yielding either a continuous spectrum or a relatively re-.

stricted band of such spectrum, and the determination, in the case of the continuous spectrum, of those ,wave lengths which are absorbed by the specimen upon trans. mission of the beam through or reflection of the beam from the specimen. V g

It is frequently desirable, especially in biological research, to make local spectrographic analysis of a specimen, that is, to determine the elements present in the specimen in a particular relatively small section or area thereof. Existing spectrographic systems may be employed in making such local analyses where the specimen and the area thereof to be examined are relatively large. Thus, in the prior, systems the beam of radiant energy is impinged on a selected point or area of the specimen either by visually observing the point of impingement of a beam of visible light on the specimen and adjusting the position of the latter to place the selected point or area and the point of impingement in coincidence, or by positioning the selected point or area of the specimen directly in line with the exit aperture through which radiant energy is received.

In the alternative, the specimen may be dissected to provide a specimen which includes only the desired area of the original specimen and this used as the specimen to be analyzed.

The difiiculties encountered in making localized, e.g., microscopic, spectrographic analyses, by the foregoing methods, where the area of investigation and/ or the specimen are relatively small will be evident. Thus, frequently the size of the specimen is of microscopic order and, accordingly, the area of investigation may be so infinitesimally small to render it impossible to dissect the specimen to provide a specimen including only the desired area of investigation.

While the difficulty of dissection is not involved in making microspect'rographic analyses by impinging a beam of radiant energy on a desired point of a microspecimen, it will be apparent that in this latter method there is involved the equally difficult problem of accurately impinging, on a desired point on a specimen of microscopic size, a beam of radiant energy whose effective diameter may be several times smaller'than the dimensions of the specimen. V

Accordingly, it may be stated as a general object of this invention to provide an improved system for making spectrographic analyses.

\ 2,913,584 Patented Nov. 17, 1959 Another object of the invention is the provision of a system for making microspectrographic analyses.

And another object of the invention is the provision ofpingement of a beam of radiant energy on a desired locus of investigation of a microspecimen.

And a further object of the invention is the provision of a system as in the foregoing wherein the point of impingement of the beam on the specimen may be readily varied at will and accurately located on the specimen.

A further object of the invention is the provision of a microspectrographic system, as above, wherein there is presented to the operator an enlarged image of the microspecimen which image has accurately indicated thereon the point of impingement of the radiant energy beam on the specimen.

Still a further object of the invention is the provision of such a microspectrographic system wherein the light for illuminating the specimen to provide said enlarged image is in the ultraviolet range of the spectrum so as to provide an enlarged image of greater clarity and definition.

And still a further object of the invention is the provision of a microspectrographic system, as in the foregoing, wherein said enlarged image may be one in which the absorption of certain wave lengths of radiant energy radiant energy for impinging the specimen at a selected point, providing means for indicating on said enlarged image when the flying spot scans said point of impingement, providing means for varying the wave length of said radiant energy, and providing means for recording or otherwise indicating the absorption of the specimen for said radiant energy as the Wave length thereof is varied over a desired band of wave lengths.

A better understanding of the invention as well as a fuller appreciation of its objects, features, and advantages may be had by a reading .of the following detailed descrip tion of the invention wherein reference is had to the ac companying drawings in which:

Fig. 1 is a schematic showing, in perspective, of a preferred form of the present system for making microspectrographic analyses; and

Fig. 2 is a schematic showing, on reduced scale, of a portion of the system of Fig. 1 with the parts thereof modified to provide a color display of the enlarged image of the specimen.

Reference is now made to Fig. 1 of the drawings where in there is shown a schematic diagram of an embodiment of the invention.

Designated at 10 and 11 are a projection type kinescope and a monitoring kinescope, respectively, which are energized from voltage supplies, not shown, and scanned in synchronism from a common synchronizing generator 12 so that at any given instant of time, the flying spots, forming the rasters on the tubes, will occupy the same relative positions in their respective field scans.

The screen ofprojection tube 10 is preferably, though not necessarily, coated with a substance which will yield a raster in the ultra violet range of the spectrum and which has a relatively low persistence value. The screen of monitoring tube 11 is coated with a substance which wiH yield a visible raster.

forming the monitor tube raster.

Projection tube has its optical axis alined with the optical axis of a microscope 13, the beam of energy produced by the flying spot forming the raster on tube 10 being projected into the eyepiece end of the microscope and the latter being adjusted to form a reduced image of such raster on a specimen plate 14 disposed at the objective end of the microscope. This raster image, then, will be reduced in the order of the power of the microscope.

Disposed below specimen plate 14, and in a position to receive the ultra violet light transmitted through the plate, is a photo-multiplier tube 15. whose output is coupled to the control grid of monitor tube 11 through a video amplifier 16. This photocell has primary sensitivity to the wave lengths present in the projection tube raster.

The above described system constitutes a conventional flying spot microscope which operates as follows:

7 When a specimen 17 is mounted on specimen plate 14 and the latter is positioned so as to place the specimen on the optical axis of the microscope 13, the flying spot, resulting from the impingement of the beam of energy from the projection tube on the specimen, will scan the specimen, the cross sectional area of the beam being reduced by the microscope 13 to a value substantially less than the area of the specimen. The intensity of the ultra violet light transmitted through the specimen and received by photocell 15 will vary during a given field scan of the flying spot in accordance with the varying opacity of the specimen to ultra violet light along the sweeps constituting the field scan.

. The varying output of photocell 15, resulting from the varying intensity of the light received thereby, acts to modulate the intensity of the electron beam in the monitor tube and hence the intensity of the flying spot of light Since this latter tube is scanned in synchronism with the scanning of the specimen, there will be produced on the screen of the monitor tube a visual, enlarged, half-tone image or picture 18 of the specimen.

It is desirable that the specimen 17 be illuminated in the ultra violet band of the spectrum to produce the enlarged image 18 since, as is well known, such illumination will result in an image of maximum definition and clarity.

To enable microspectrographic analyses to be made of the specimen, there is provided a light source 19 including means 20 for producing a beam of light yielding a band of wave lengths with which a selected point of the specimen is to be progressively illuminated. The beam of light from means 20 is passed through a monochromator 21 of any conventional design and the emerging monochromatic beam of light is passed through a minute aperture or pin hole 22 in a mask 23 and impinged on a mirror 24. Monochromator 21 includes suitable means 25 for varying the wave length present in the beam emerging from exit aperture 22 over the aforementioned band of wave lengths.

On the opposite side of mirror 24 to light source 19 is a position detector 26 comprising a mask 27 having an entrance aperture 28 therein and a photomultiplier tube 29 positioned behind mask 27 for receiving light entering through aperture 28. The output of photocell 29 is coupled to the control grid of monitor tube 11 through video amplifier 16 and a switch 30.

The optical axis 0 of light source 19, namely, the path traversed by the beam of light emerging from exit aperture 22, and the optical axis 0 of position detector 26, namely, the axis passing through entrance aperture 28 normal to the plane thereof, are both disposed in planes normal to the optical axis 0 of the projection tube 10 and microscope 13. For facility of description, the optical axes O and 0 of the light source and position detector will be assumed to occupy horizontal planes and the optical axis 0 of .the projection tube and microscope will be assumed to occupy a vertical plane.

Light source 19 and position detector 26 are each horizontally and vertically adjustable on a support 31, as indicated by the arrows in Fig. l, for reasons to be presently seen. Suitable adjustable mountings, not shown, would, in practice, be provided for accommodating such vertical and horizontal adjustment of the position detector and light source. 7

Mirror 24, which comprises a semi-transmissive reflecting surface, is fixedly mounted on support 31 with its reflecting surface disposed in a plane inclined at a 45 angle to the vertical and horizontal planes and normal to vertical planes passing through optical axes O and 0 t of the position detector and light source, all as illustrated.

From the description thus far it will be seen that mirror 24 will reflect the beam of energy from the projection tube toward position detector mask 27, there being a suitable lens system 32 interposed between the mirror and mask 27 so as to form an image of projection tube raster on the mask. Owing to the semi-transmissive reflecting surface of the mirror, a portion of the beam from the projection tube will also be projected through microscope 13 so that the aforementioned reduced image of the projection tube raster will be formed on specimen plate 14.

It will also be apparent that if position detector 26 is so vertically and horizontally positioned as to place its aperture 28 within the raster image formed on its mask 27, the reflected beam producing this latter raster image will scan the aperture once during each complete frame scan, the diameter of the aperture being on the order of the diameter of the reflected beam. As will be obvious, this scanning of aperture 28 will occur at the instant the beam of energy from the projection tube 10 scans the point of intersection of the position detector optical axis 0 with the reflecting surface of the mirror. At each scanning of the aperture, position detector photocell 29 will generate an output pulse which, upon being applied to the control grid of the monitor tube 11, will modulate the electron beam intensity therein with the resultant formation of a bright spot or pip 33 in the monitor tube raster. By adjusting the position of the position detector in the, directions indicated it will be seen that aperture 28 will be scanned at diiferent points in the complete field scan of the projection tube and the position of pip 33 in the monitor tube raster will shift accordingly.

Assuming for the moment that the optical axes O and 0 of the position detector and light source 19 are in coincidence, their common optical axis will intersect the reflecting surface of mirror 24 at a given point and a portion of the beam of monochromatic light emerging from exit aperture 22 in light source mask 23 will be reflected downwardly from said point in a vertical plane through microscope 13, wherein it is reduced in diameter according to the power of the microscope to produce a beam cross sectional area substantially less than the area of the specimen, and will impinge specimen plate 14 at some point in the previously mentioned raster image formed thereon.

, Whenever the beam of energy projected from tube 10 scans the point of intersection of axes O and 0 with the reflecting surface of mirror 24, the portion of this projected beam transmitted through the semi-transmissive reflecting surface of the mirror and the. monochromatic light-beam reflected from such point will be in coincidence. It will be recalled, also, that whenever said projected beam scans the point of intersection of the optical axis 0 of the position detector with the reflecting surface, the detector photocell 29 will generate an output pulse to form a pip on the monitor tube raster. Thus, it will be apparent that when the position detector and light source are alined in a manner to place their optical axes in coincidence, position detector photocell 29 will generate an output pulse at the instant the flying spot forming the raster image on specimen plate 14 scans the point of impingernent of the monochromatic beam, from light source 19, on the plate. Since monitor tube 11 and projection tube 10 are scanned in synchronism, it will be obvious that the pip 33 will have the same relative position in the monitor tube raster as the aforesaid point of impingement occupies in the raster image formed on the specimen plate 14.

Thus, when a specimen 17 is mounted on the plate 14 and positioned to be scanned by the flying spot forming said latter raster image, the enlarged image or picture 18 of the specimen formed on the monitor tube screen will have indicated thereon, by said pip, the exact point of impingement on the specimen of the monochromatic beam from light source 19. In a preferred form of the invention, the position detector and light source are so positioned, as will presently be more fully explained, that the beam of monochromatic light from source 19 is reflected from mirror 24 along the optical axis of the projection tube and microscope. Under such conditions, of course, the pip 33 in the monitor tube raster will be at the geometric center of the latter.

Referring now again to Fig. 1 of the drawings, a second photo-multiplier tube 34 is disposed above the specimen plate 14 in a position to receive light, from source 19, reflected from the specimen and a third photo-multiplier tube 34 is disposed below the plate to receive such light transmitted through the specimen. Tubes 34 and 34 have primary sensitivity to the wave length present in the light from means 20. This light generally does not include the ultra violet range.

The outputs of photocells 34 and 34 are adapted to be selectively applied, through appropriate actuation of a switch 35, to a recorder amplifier 36, the output of which in turn is fed to a recording device 37. This recording device may, for example, be mechanically coupled to the wavelength adjusting means 25 of the monochromator 21, as indicated at 38, for feeding a strip of recording paper 39 in the direction of its length as the wave length of the monochromatic beam of light impinged on the specimen from source 19 is varied. The device may also comprise a stylus 40 and means 41, to which the output of the recorder amplifier is applied, for positioning the stylus 40 transversely of the strip of recording paper 39 as a function of the output of the recorder amplifier. Thus there may be obtained, as will presently be more fully appreciated, a graph or plot 42 of absorption of the specimen, at a selected point thereof, versus wave length.

A preliminary step in the operating procedure of the above described system involves the linearizing of the system and the centering of the tube rasters about the optical axis 0 of the tube, in the case of the projection tube, and about a mark C, indicating the center of the screen, in the case of the monitor tube.

Although this linearizing of the system and centering of the tube rasters may be accomplished in numerous ways, the preferred practice would be to impress on the control grid of the projection tube 10, from a source 43, and through a video amplifier 44, a dot linearity pattern signal such as a 630 kc. signal, where a second field scanning period is employed. This signal results in the formation of the well known dot linearity pattern in the projection-tube raster. The circuits associated with the projection tube are then adjusted, in the well known manner, to center this pattern about the optical axis 0 of the tube and render the pattern linear.

Photocell 15 will generate a pulsed output as a result of the dot linearity pattern in the projection tube raster, and the electron beam intensity in the monitor tube will be modulated by this pulsed output so there will be produced a corresponding dot linearity pattern in the raster of the monitor tube 11. The circuits associated with this latter tube are adjusted, in the well known manner, to center the pattern about the center mark C and to render the pattern linear. Source 43 is now disconnected from the projection tube, as by opening of a switch 45.

A second preliminary step in the operating procedure previous centering of the monitor tube raster, coincideswith the geometric center of that raster. It will be seen that when the position detector 26 is positioned to center the pip 33 in the monitor tube raster, the optical axis 0 of the detector will pass through the point of intersection of the optical axis 0 of the projection tube and microscope with the reflecting surface of mirror 24. Projection tube 10 is now shut oif by the actuation of suitable controls, not shown, in the synchronizing generator 12, or an opaque mask is inserted between that tube and mirror 24. Light source 19 is now energized whereupon a portion of the monochromatic beam of light emerging from light source aperture 22 will be transmitted through the semi-transmissive reflecting surface of mirror 24 and will impinge position detector mask 27. Light source 19 is vertically and horizontally adjusted to aline its optical axis with that of the position detector. When such condition of alinement exists, the transmitted beam will pass through position detector aperture 28 and impinge photocell 29 with a resultant increase in the intensity of the monitor tube raster.

When the optical axes O and 0 of the position detector and light source are thus alined, the monochromatic beam of light emerging from the exit aperture of the source will impinge the reflecting surface of the mirror at said point of intersection therewith of the optical axis 0 of the projection tube and microscope. The beam will, therefore, be reflected from the mirror along this latter axis.

It will be apparent, accordingly, in the light of previous discussion, that when the projection tube is reenergized to produce a raster image on the specimen plate 14 and the specimen 17 is positioned to be scanned by the flying spot of this image, the pip 33 in the enlarged specimen image on the monitor tube will indicate the point of impingement of the monochromatic beam on the specimen. However, since the position of the pip coincides with the center mark C on the monitor tube face, switch 30 may be opened to disconnect position detector photocell 29 from the monitor tube.

The monochromatic beam may be impinged on any selected point of the specimen by shifting the specimen plate 14 to place the selected point, as viewed on the enlarged image on the monitor tube, in coincidence with center mark C.

A selected one of the photocells 34 and 34' is now coupled to the recorder amplifier by actuation of switch 35 and monochromator 21 is operated to vary the Wave length, present in the monochromatic beam over a desired band of wave lengths.

The output generated by the selected one of the photocells 34 and 34' will comprise a DC. signal resulting from the transmission of the monochromatic beam through, or reflection of such beam from the specimen, depending on which photocell is employed.

It will be obvious, therefore, that the output applied to means 41 of the recording device 37 will be a function of the extent of transmission or reflection of the monochromatic beam by the selected point of the specimen and, accordingly, a function of the absorption of the specimen for the various wave lengths in the band of Wave lengths over which the latter beam is varied. Rec- This spectrographic analysis procedure may be repeated for each point of the specimens In a modified form of the system, support 31, which mounts the position detector and light source, is made adjustable in the horizontal plane. In operating this modified system, position detector 26 and light'source 19 are adjusted, as before, to bring their optical axes into coincidence.

In lieu, however, of adjusting the specimen plate 14 to vary the point of impingement of the monochromatic beam on the specimen, the latter may be positioned so that its enlarged image is centered on the monitor tube and support 31 is shifted in the horizontal plane to direct the reflected monochromatic beam onto a selected point of the specimen.

It will be obvious, in the light of previous discussion, that when position detector photocell 2.6 is coupled to the control grid of the monitor tube and'the detector and light source are alined, the position of the pip 33 in the enlarged specimen image will indicate the exact point of impingement of the beam on the specimen.

The remainder of the system and its operation are identical to that of the preferred embodiment and, therefore, no further description is deemed necessary.

Reference is now made to Fig. 2 wherein a modification to the basic system of Fig. 1 is illustrated, which modification yields a color display on the monitor tube wherein the differences in wave length absorption of the specimen are translated into color differences.

To provide such a color display, kinescope 11 in the basic system is replaced by a color kinescope 50, such as a conventional tri-color kinescope incorporating red, blue, and green electron guns 51, 52, and 53, respectively. Three photo-multiplier tubes 54-, $55, and 56 are disposed below the specimen plate 14 in position to receive the light transmitted through the specimen 17 when the latter is scanned by the flying spot forming the aforementioned raster image on the specimen.

Each of these three photocells is made sensitive to a particular band of the wave lengths present in the beam projected onto the specimen from the projection tube 1'1 as by interposing appropriate filters 54, 55, and 56' in front of each photocell. The output of each of the photocells is coupled to one of the electron guns S1, 52, and 53 through appropriate video amplifiers 57, 58, and

For example, photocell 54 may be sensitive to a band of wave lengths from 200 to 250m photocell 55 to a band of wave lengths from 250 to 300 m and photocell 56 to a band of wave lengths from 30 to 350 mg. Photocell 54 is coupled to the red electron gun 5i, photocell 55 to the blue electron gun 52, and photocell 56 to the green electron gun 53, as illustrated.

As the specimen 17 is scanned by the flying spot of the raster image, the outputs of photocells 54, 55 and 56 will vary in accordance with the varying opacity of the specimen, along the scan lines, to the particular band of wave lengths to which the respective photocells are made sensitive. These outputs, when applied to their respective electron guns 51, 52, and 53 will yield on the screen an enlarged color image of the specimen wherein the color at each point of the specimen image may be identified with each of the band of wave lengths with which the specimen is scanned. A color of a particular point of the specimen image will, of course, be indicative of the relative opacity of the specimen at that point to the bands of wave lengths with which the specimen is scanned.

As in the preferred embodiment of the system, a photocell 34 is disposed above the specimen plate 14 to receive the monochromatic light reflected from the specimen 17, and a photocell 3 3 is disposed below the plate to receive monochromatic light transmitted through the specimen. These photocells may be selectively coupled to the recorder amplifier 36 (Fig. 1), by the operation of switch means 35. The remainder of the system and its operation is. identical to that previously described. No further illustration of this latter modified system or its operation is, therefore, deemed necessary..

8. From the'foregoing description, it will be apparent that there has been described a system for making microspectrographic analyses of specimens and microspecimens which is fully capable of securing the advantages and achieving the objects heretofore set forth. It will be appreciated that many changes may be made in the system depending upon its intended application. Consequently, while certain forms of the invention have been illustrated and described, it should be understood that the invention is not to be restricted to such described and illustrated forms except as limited by the following claims.

I claim:

1. In a system of the class described, means for forming an image of an object on a viewing screen including means for scanning the object with a first beam of energy which is small in cross-section relative to the object, means for scanning the viewing screen with a second beam of energy in synchronism with the scanning movements of said first beam, and means for receiving energy of said first beam from the object and modulating the intensity of said second beam in accordance with variations in the intensity of the energy received from the object; means for impinging on a selected point of the object a third beam of energy which is small in cross-section relative to the object; and means for modulating the intensity of said second beam when said first beam scans said point to produce a visual indication of said point on said image.

2. In a system of the class described, means for form-- ing an image of an object on a viewing screen including means for scanning the objectwith a first beam of energy which is small in cross-section relative to the object, means for scanning the viewing screen with a second beam of energy in synchronism with the scanning movements of said first beam, and means for receiving energy of said first beam from the object and modulating the intensity of said second beam in accordance with variations in the intensity of the energy received from the object; means for impinging on the object a third beam of energy which is small in cross-section relative to the object; means for relatively shifting said third beam and the object to impinge said third beam on any selected point of the object; and means for modulating the intensity of said second beam when said first beam scans said point to produce a visual indication of said point on said image.

3. In a system of the class described, means for forming an image of an object on a viewing screen including means for scanning the object with a first beam of energy which is small in cross-section relative to the object, means for scanning the viewing screen with a second beam of energy in synchronism with the scanning movements of said first beam, and means for receiving energy of said first beam from the object and modulating the intensity of said second beam in accordance with variations in the intensity of the energy received from the object; means for impinging on a selected point of the object a third beam of energy which is small in cross-section relative to the object; means including energy sensitive means sensitive to the energy of said first beam for sensing scanning of said point by said first beam and modulating the intensity of said second beam when said first beam scans said point to produce a visual indication of said point on said image.

4. In a system of the class described, means for form ing an image of an object on a viewing screen including means for scanning the object with a first beam of energy which is small in cross-section relative to the object, means for scanning the viewing screen with a second beam of energy in synchronism with the scanning movements of said first beam, and means for receiving energy of said first beam from the object and modulating the intensity of said second beam in accordance with variations in the intensity of the energy received from the object; means for impinging on a selected point of the object a third beam of energy which is small in crosssection relative to the object; energy sensitive means sensitive to the energy of said first beam and connected to said first-mentioned means-for modulating the intensity of said second beam in response to said energy sensitive means receiving energy of said first beam; and means for directing a portion of said first beam to said energy sensitive means when the latter beam scans'through said point whereby to produce a visual indication of said point on said image.

5. In a system of the class described, means for forming an image of an object on a viewing screen including means for scanning the obiect with a first beam of energy which is small in cross-section relative to the object, means for scanning the viewing screen with a second beam of energy in synchronism with the scanning movements of said first beam, and means for receiving energy of said first beam from the object and modulating the intensity of said second beam in accordance with variations in the intensity of the energy received from the object; means for impinging on a selected point of the object a third beam of energy which is small in crosssection relative to the object; energy sensitive means sensitive to the energy of said first beam and connected to said first-mentioned means for modulating the intensity of said second beam in response to said energy sensitive means receiving energy of said first beam; and an element having a semi-reflecting surface disposed in the path or' said first beam and arranged to reflect a portion of the first beam to said energy sensitive means when the latter scans through said point whereby to produce a visual indication of said point on said image.

6. In a system of the class described, means for form ing an image of an object on a viewing screen including means for scanning the object with a first beam of energy which, is small in cross-section relative to the object, means for scanning the viewing screen with a second beam of energy in synchronism with the scanning move ments of said first beam, and means for receiving energy of said first beam from the object and modulating the intensity of said second beam in accordance with variations in the intensity of the energy received from the object; energy sensitive means sensitive to the energy of said first beam and connected to said first-mentioned means for modulating the intensity of said second beam in response to said energy sensitive means receiving energy of said first beam; an element having a semi-reflecting surface disposed in the path of and scanned by said first beam and arranged to reflect a portion of the latter beam to said energy sensitive means when said first beam impinges a predetermined point of said surface; and means for directing a third beam of energy whichis small in cross-section relative to said object onto said point of the surface in such a way that a portion of the latter beam is reflected to the object along a path coincident with the first beam when the latter impinges said point, whereby modulation of said second beam upon scanning of said first beam through said point of the surface produces on said image a visual indication of the point of impingement of the third beam on the object.

7. The subject matter of claim 6 including a common support means mounting said energy sensitive means, element, and source of the third beam for unitary adjustment thereof in a transverse plane of the first beam to impinge said third beam on different points of the object. I 8. In a system of the class described, means for frming an image of an object on a viewing screen including means for scanning the object with a first beam of energy which is small in cross-section relative to the object, means for scanning the viewing screen with a second beam of energy in synchronism with the scanning movements of said first beam, and means for receiving energy ofsaid first beam from the object and modulating the intensity of said second beam in accordance with variations in the intensity of the energy received from the object; means for impinging on a selected point of the object a third beam of energy which is small in cross-sec-' 10 tion relative to the object; means for varying the wavelength of the energy of said third beam; and means for modulating the intensity of said second beam when said first beam scans said point to produce a visual indication of said point on said image.

9. In a system of the class described, means for forming an image of an object on a viewing screen including means for scanning the object with a first beam of energy Which is small in cross-section relative to the object, means for scanning the viewing screen with a second beam of energy in synchronism with the scanning movements of said first beam, and means for receiving energy of said first beam from the object and modulating the intensity of said second beam in accordance with variations in the intensity of the energy received from the object; means for impinging on a selected point of the object a third beam of energy having a wavelength which is different from that of the energy of said first beam and which third beam is small in cross-section relative to the object; means for receiving and sensing the intensity of the energy of said third beam after impingement of the latter on the object; and means for modulating the intensity of said second beam when said first beam scans said point -to produce a visual indication of said point on said image.

10. In a system of the class described, means for forming an image of an object on a viewing screen including means for scanning the object with a first beam of energy which is small in cross-section relative to the object, means for scanning the viewing screen with a second beam of energy in synchronism with the scanning movements of said first beam, and means for receiving energy of said first beam from the object and modulating the intensity of said second beam in accordance with variations in the intensity of the energy received from the object; means,

for impinging on a selected point of the object a third beam of energy having a wavelength which is different from that of the energy of said first beam and which third beam is small in cross-section relative to the object; meansfor receiving and sensing the intensity of the energy of said third beam which is transmitted through the object; and means for modulating the intensity of said second beam when said first beam scans said point to produce a visual indication of said point on said image.

11. In a system of the class described, means for form ing an image of an object on a viewing screen including means for scanning the object with a first beam of energy which is small in cross-section relative to the object, means for scanning the viewing screen with a second beam of energy in synchronism with the scanning movements of said first beam, and means for receiving energy of said first beam from the object and modulating the intensity of said second beam in accordance with variations in the intensity of the energy received from the object; means for impinging on a selected point of the object a third beam of energy having a wavelength which is different from that of the energy of said first beam and which third beam is small in cross-section relative to the object; means for receiving and sensing the intensity of the energy of said third beam which is reflected from the object; and means for modulating the intensity of said second beam when said first beam scans said point' to produce a visual indication of said point on said image.

12. In a system of the class described, means for forming an image of an object on a viewing screen including means for scanning the object with a first beam of energy which is small in cross-section relative to the object, means for scanning the viewing screen with a second beam of energy in synchronism with the scanning movements of said first beam, and means for receiving energy of said first beam from the object and modulating the intensity of said second beam in accordance with variations in the intensity of the energy received from the object; means for impinging on a selected point of the object a third beam of energy which is small in cross-section relative to.

the object; said first-mentioned means and said means for impinging said third beam on the object comprising optical means located in the paths of said first and third beams for focusing the latter on the object whereby to reduce the cross-section of the latter beams at the object; and means for modulating the intensity of said second beam when said first beam scans said point to produce a visual indication of said point on said image.

13. In a system of the class described, means for forming an image of an object including means for scanning the object with a first beam of energy which is small in cross-section relative to the object, a viewing kinescope tube, means for scanning the electron beam of said tube in synchronism with the scanning movements of said first beam, and means for receiving energy of said first beam from the object and modulating the intensity of said electron beam in accordance with variations in the intensity of the energy received from the object whereby to form an image of said object on the face of said tube; means for impinging on a selected point of the object a third beam of energy which is small in cross-section relative to the object; and means for modulating the intensity of said electron beam when said first beam scans said point to produce a visual indication of said point on said image.

14. In a system of the class described, means for forming an image of an object including means for scanning the object with a first beam of energy which is small in cross-section relative to the object, a color viewing kinescope tube, means for scanning the electron beams of said tube in synchronism with the scanning movements of said first beam, said first beam comprising energy of three difierent predetermined wavelengths, three energy sensitive means each sensitive to one of said wavelengths and arranged to receive energy of said first beam after impingement of the latter on the object, and means connecting said energy sensitive means to the grid of said tube for modulating the electron beams of the tube in accordance with the variations in the intensity of the respective wavelengths of energy of the first beam received by said energy sensitive means whereby to produce a color image of the object on the face of said tube, the color of any particular portion of said image being indicative of the relative absorption of said three wavelengths of energy by the object; means for impinging on a selected point of the object a third beam of energy which is small in cross-section relative to the object; and means for modulating the intensity of said electron beams when said first beam scans said point to produce a visual indication of said point on said image.

15. The subject matter of claim 14 wherein the wavelength of said third beam is different from said predetermined wavelengths, and means for receiving energy of said third beam from the object and sensing the intensity of the latter energy.

16. Apparatus for making microspectrographic analyses of a specimen, comprising: means for producing on a viewing screen an image of the specimen including means for scanning the specimen with a first beam of energy, means for scanning said screen with a second beam of energy in synchronism with the scanning of the specimen by the first beam, means for modulating the intensity of said second beam in accordance with the variations in intensity of the first beam after impingement of the latter on the specimen, means for impinging on the specimen a third beam of energy, means for varying the wave length of said third beam over'a band of wave lengths differing from the wave length of the first beam, means for receiving and sensing the energy in the third beam after impingement of the latter on the specimen, and means for indicating on said image the point of impingement of the third beam on the specimen.

17. The subject matter of claim 16 including means for shifting said third beam to impinge the latter on'different points of the specimen.

18. In a system for making microspectrographic analyses of a specimen, means for forming an enlarged image of the specimen including means for scanning a given area of a specimen with a first beam of energy in a given region of the spectrum and having a cross sectional area substantially smaller than said given area, a viewing screen, means for scanning said screen over an area substantially greater than said given area with a second beam of energy and in synchronism with the scanning of the specimen by the first beam to produce on the screen a visible raster having an intensity determined by the intensity of said second beam, and means for modulating the intensity of said second beam in accordance with the variations in the intensity of said first beam after it has impinged the specimen whereby to form an enlarged image of the specimen; a semi-transmissive reflecting element disposed in the path of said first beam, said element having a semi-reflective surface transmitting a portion of said first beam to the specimen; means for producing a third beam of energy in a different region of the spectrum and having a cross sectional area substantially smaller than the specimen, said last mentioned means being adjustable to impinge said third beam on a point of said reflecting surface scanned by the first beam at an angle of incidence such that said third beam will be reflected onto the specimen in coincidence with the first beam when the latter scans said point; and means for modulating the intensity of said second beam when the first beam scans said point.

19. In a system of the class described, means for scanning a beam of energy through a given field scan, means for detecting scanning of said beam through a given position in its field of scan including an element having a semi-reflecting surface inclined to and arranged to be scanned by said beam, said surface transmitting a portion of said beam and reflecting a portion of said beam in a transverse direction of said transmitted portion, energy sensitive means sensitive to the energy of said beam and having a narrow energy sensitive zone located to be impinged by said reflected portion of the beam when the latter scans through a given point on said surface, and means for adjusting said element and energy sensitive means as a unit in a transverse direction of the beam to locate said point in diiferent positions in said field of scan whereby to vary the scanning position of the beam wherein said energy sensitive means receives the beam.

20. In a system of the class described, means for scanning a first beam of energy through a given field scan, means for generating a second beam of energy having a wave length different from the first beam, means for directing a portion of said second beam along a path such that said first beam scans through a position of coincidence with said portion of the second beam, means for scanning a third beam of energy in synchronism with scanning of the first beam, and means for modulating the intensity of the third beam in response to scanning of the first beam through said position.

21. The subject matter of claim 19 wherein said last mentioned means comprises sensing means sensitive to the energy in said first beam and means for directing a portion of the first beam to said sensing means when the first beam scans through said position.

22. In a system for making microspectrographic analyses of a specimen, means for scanning a given area of the specimen with a first beam of energy yielding predetermined wave lengths, three energy sensitive means arranged to receive said beam after it has impinged the specimen, each of said sensitive means being responsive to a different wave length in said beam, color kinescope means scanned in synchronism with the scanning of the specimen and having the outputs of said sensitive means applied thereto for producing a color image of the specimen, the color at any given point of the image being indicative of the relative absorptions of the specimen for the wave lengths to which said sensitive means are responsive.

References Cited in the file of this patent UNITED STATES PATENTS 1,648,058 Parker Nov. 8, 1927 1,709,762 Zworykin Apr. 16, 1929 2,423,254 Rettinger July 1, 1947

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