MICRO DISPLAY MONITOR

Abstract: A photomicrographic camera system in which a mirror system (26, 30) is utilized to deflect the light beam emanating from the eyepiece (20) of a properly illuminated, compound optical microscope (10) horizontally outward to another mirror which then deflects the beam vertically downward to a film holder (36) containing a sensitized photographic film of paper material. An appropriate housing (32) confines the optical path and protects the film from stray light, while at the same time providing structural support for the mirrors and auxiliary photographic components, such as baffles (57), shutter (48), filters (46), etc. Since the projection distance is more than doubled, very large format images can be achieved easily with a system sitting on top a desk in a room of conventional ceiling height. By reversing the optical path through the system, high resolution microphotographs, microdots, or images for microelectronic component fabrication can be obtained utilizing the same structure. The invention may also be configured as a micro display monitor (100) having a rear projection screen (108), which may be displaced by a film holder (114), so as to provide the functions of both a real time monitor and a photomicrographic camera.

Description: MICRO DISPLAY MONITOR Cross Reference to Related Application This application is a continuation-in-part of co- pending U.S. patent application serial number 481,455, filed April 1, 1983. Field of the Invention This invention relates to photomicrographic camera systems, and more particularly is concerned with camera systems capable of producing direct first generation photomicrographic images of large format on photographic film and paper materials. Specifically, it relates to a photomicrographic/macrophotographic camera system employing a folded optical system which allows direct images of high resolution to be displayed in real time on a large screen in full color, and photographed when desired. The Micro Display Monitor works with most conventional optical microscopes. Background of the Invention In U»S. Pat. No. 1,161,556 there is described a vertical photomicrographic camera system in which the image from the microscope is projected vertically upward to the photographic film which is located at the top of a telescoping, light tight box. This patent discloses structure connecting the microscope to the photographic plate holder with a bellows and holding the camera aloft by means of adjustable rod stands. Also disclosed is structure for housing this camera in a physician's desk. To operate this camera, the observer looks down on the top of the ground glass screen upon which the image from the microscope is projected, while he reaches down to adjust the focus control of the microscope. Because of this, the projection distance is essentially limited to the length of the human arm, and therefore film formats larger than 4"X5" could not be conveniently used with this device. In U.S. Pat. No. 2,077,809 is described a camera mounted on a vertical stand and connected to a microscope by means of a bellows. This device physically resembles a reflex camera, but it is nonfunctional as described and illustrated. As described in the claims there is "a horizontal negative holder on said camera upon which the picture taken by the camera of the object under observation by the microscope is directly reflected to display same to an observer simultaneously with the developing of the picture in the camera." If the microscope image falls upon an opaque plate as claimed so that the observer can see it, then the image will not reach the film to expose it. As we are not told to remove the plate prior to exposure, and as there is no means shown for tilting it out of the beam or sliding it out of the camera, the camera will not function as described. This patent also describes a drawing apparatus which employs a mirror to reflect the light to a drawing plane, the beam of light being received from the tube of the microscope which has been "laterally swung" for the purpose of making drawings of the object. However, this tube is now at a sharp angle with respect to the microscope optical axis. Light received by the microscope objective will not enter this tube, unless special reflecting optics are included in the body of the microscope. Since no such optical elements are shown or described in this patent, it must be concluded that this aspect of the invention is also incapable of operating as described. In U.S. Pat. No. 2,351,753, Flint et al. describe a vertical photomicrographic camera with a bellows connecting the microscope to the camera head. Height of the camera head is adjustable by means of rack and pinion method and a counterbalance system is provided to offset the weight of the camera. The camera head is provided with a pivotable mirror, which can reflect the image to a ground glass screen at the front to be used for focussing, and then pivoted out of the optical beam as the film is exposed. A hood is provided around the ground glass screen to cut down on the undesirable effects of overhead lighting during focussing. The concepts and methods set forth in this patent have dominated the field of large format photomicrography for the past four decades. These same methods are employed in the recently marketed enro MP 812 photomicrographic camera system. This is an 8"X10" camera system which is capable of providing images on the recently released 8"X10" Polaroid Print Film and Transparency material. This camera also consists of a large vertical stand which holds the camera head above the microscope. Focussing is accomplished by means of deviating the image to a large ground glass screen which is partially shielded from room lights by a hood. The camera head is connected to the microscope by means of a bellows system. This is indeed a large format photomicrographic camera system based upon the art and structure of the Flint et al. patent. Reflex cameras of slightly smaller format (e.g. 4"X5") have also been coupled to microscopes by means of solid, plastic or metal, conical tubes that, serve both as the structural support for the camera, and also as the light tight bellows. Devices such as this are currently available as photomicrographic cameras for the Olympus, Nikon, and other microscope systems. These devices are also provided with reflex view focussing means. Other devices are available that allow a worker to connect a single lens reflex camera (such as a modern 35 mm camera) to the microscope. Some of these, such as the Nikon F adapter, were designed with the correct realization of the importance of a small, positive correcting lens when the microscope image must be focussed at a very short (4"-6") projection distance. Others are now marketed without a correcting lens, and the worker achieves focus by focussing the microscope, which results in the objective lens being significantly away from the position at which it was designed to operate. This results in degradation of the quality of the resultant picture. These adapters simply constitute light tight tubes that link the 35 mm camera to the microscope and support it above the microscope with the film plane centered on the optical axis of the microscope. Focussing is accomplished by looking in the camera reflex view port. In the case of the Nikon system, a specially configured ground glass screen may be mounted in the camera to facilitate focussing at low light levels as is encountered at high magnifications and in dark field photomicroscopy. It is therefore an object of the present invention to provide a new and improved method and means of producing large format real time displays and photo¬ micrographs of images from conventional optical microscopes. Summary of the Invention According -to the present invention large format photomicrographs may be -produced by means of a camera employing a folded optical system that allows the beam from the microscope to travel first vertically upward to a flat mirror. This mirror deflects it horizontally across to another mirror which deviates the beam vertically downward toward the film plane. The camera that is configured in this manner may be used with any conventional optical microscope which is illuminated with a high intensity light source used in accordance with the proper teachings of microscopy (e.g. Koehler illumination, critical illumination, Dark Field Illumination, Phase Contrast Illumination, etc.). The camera in the preferred embodiment of the present invention involves a structural housing of three components. There is a neck that provides optical and structural coupling with the microscope eyepiece and protrudes vertically upward, thus affording a light tight pathway through which the diverging beam from the microscope eyepiece propagates. This neck is connected to a horizontal arm which also provides a light tight path for propagation of the microscope beam, after it has been reflected in this direction by means of a mirror situated at the top of the neck and oriented at substantially a 45 degree angle with respect to the vertical. The arm is connected to a tall vertical box which houses a large mirror that deviates the expanding beam downward to the bottom of the box, upon which rests the easel or film plate holder which holds the photographic sensitive medium. In the neck are located necessary or desirable photographic accessories, such as the shutter, baffles, filter holder, and polarizer or polarizing analyzer. Provisions are made to allow covers to be slid into place over the mirrors to protect them from particulate contamination when the microscope camera is not in use. Focussing is accomplished by direct examination of the image as it falls upon a white focussing slide that lies immediately on top of the photographic film or paper and is removed just prior to exposure. A door in the " front of the camera is provided to facilitate focussing the image and framing and composing the picture. Alteration of image size is controlled primarily by varying the microscope magnification at the microscope itself, i.e. altering the eyepiece and objective element combination. A properly machined spacer is inserted around each eyepiece to insure that the microscope objective is at the precise position at which it was designed to operate when optimum focus of the image is achieved on the photographic film. Since the projection distance is the sum of the distance from the eyepiece to the mirror vertically overhead, plus the length of the horizontal arm, plus the vertical downward distance from the large mirror to the film plane at the base of the housing, very great projection distances can be achieved in a camera that can easily sit on top of a desk or a standard laboratory work table. With the film holder lying flat on the camera base it has no tendency to creep downward under its own weight or be unduly sensitive to vibrations. Gravity helps flatten out large sheets of film or paper, rather than trying to pull them out of their holder. Moreover, the large • ■ image displayed on the focus sheet immediately beside the microscope may be directly viewed without holding the head rigidly fixed, as is necessary when looking into an eyepiece. This freedom reduces strain and fatigue. Also, the worker can easily reach all ςontrols to adjust focus, specimen position, etc. Direct viewing of the large image on the focus sheet by two or more persons at once also facilitates communication about specific features of the image, i.e., the worker can simply point to a particular feature rather than trying to describe the location of that feature in words so that a second person can see it in the microscope. The present invention also allows the worker to readily alter film format and framing. For example, prior to recording- an image on a 20"X24" sheet of film, the photomicroscopist may de"δire to lay a 4"X5" film holder on the base to photograph a small piece of his large image, for an inexpensive measurement of focus, color balance, " exposure time, etc. The present invention also allows the photomicroscopist to record images on small format systems, such as video cameras and 35 mm cameras. When utilized in an appropriate manner, the present invention can also be employed in the production of microscopic images such as is desired for the fabrication of graticles, microdots and images which may be useful in the construction of microcircuit components. Brief Description of the Drawings A presently preferred embodiment of the invention will now be described in detail in connection with the accompanying drawings, wherein: Figure 1 is a diagramatic view of one embodiment of the invention. Figure 2 is a perspective view of one embodiment of the invention, showing the interior parts. Figure 3 is a diagram illustrating a portion of the present invention when it is used in conjunction with a small format device, such as a 35 mm camera or video camera. Figure 4 is a diagram showing the path of light rays in a simple embodiment of the camera employing only 2 mirrors. Figure 5 shows the ray path in the camera when the additional mirror is used to correct right to left orientation of the image, with mirrors 26 and 60 pivoted to proper positions for use in this mode of operation. Figure 6 shows an alternative embodiment of the invention which is completely enclosed in a modified housing. Figure 7 is a perspective view of an alternative embodiment of the invention shown in Fig. 2, with the optical path through the camera reversed, so as to make it capable of producing microphotographs, microdots or microelectronic circuits. Figure 8 is a perspective view of the micro display monitor. Figure 9 is a diagrammatic plan view of the micro display monitor, showing ho the image is reflected onto the rear projection screen. Figure 10 is a diagrammatic side view of an alternative arrangement of the micro display monitor, showing how the image may be reflected downward to a film holder mounted in the base of the monitor. Figure 11 is a side elevation of the holder frame which contains both the rear projection screen and the film holder . Figure 12 is an end view of the holder frame shown in Fig. 11, showing the rear projection screen and the film holder. Figure 13 shows a diagrammatic side view of an alternative arrangement of the micro display monitor, which allows selective use of either a primary mirror with one reflecting surface or a primary mirror with two reflecting surfaces. Figure 14 is a plan view of the micro display monitor of Figure 13 showing how the primary mirror having one reflecting surface may be moved laterally to allow use of the primary mirror having two reflecting surf ces. Figure 15 is a perspective view of an alternative embodiment of the invention shown in Figure 7 wherein the light table and original copy of Figure 7 are replaced by a video display monitor and screen, thus making it possible for the invention to produce a microphotograph of an image displayed on the screen of the monitor. Detailed Description oϊ) the Invention As may be seen in Figure 1, the camera housing 32 is a large box two to four feet high with an arm section 28 projecting out from the side of the box. A neck section 24 projects downward to cover the eyepiece 20 of the microscope 10. A rubber sleeve 22 may be used to make a light tight connection to the microscope 10. The optical section comprises an eyepiece spacer 18 (to correct for short projection distance, since the microscope is focused at infinity), a primary mirror 26, and a secondary mirror 30. If desired a tertiary mirror 60 is placed between the primary and secondary mirrors. The tertiary mirror 60 is used to get the proper and correct orientation on standard photo paper and film. If a mirror image is satisfactory, or if Polaroid film is being used, then the tertiary mirror folds back out of th " e way and is not used. Several additional optical components which may be included with the system are a shutter 48, a baffle system 57, a rotating polarizer 52, filter and holder 46, and film holder 36. The device may be equipped with an attachment for small format still, motion picture, or video cameras (Figure 3). Referring now to Figure 2, reference numeral 10 designates a standard, compound optical microscope with mirror 11 and substage condenser 17. The specimen is on microscope slide 15 with a stage 13a capable of moving the slide by adjustment of the XY controls 13. The specimen is illuminated by proper methods in accordance with the teachings of good microscopic technique (e.g. Koehler illumination, Critical illumination, etc.). When the specimen is properly focussed by means of the coarse fo.cus 16 and the fine focus 14, the light entering objective 12 is focussed to the appropriate focal point of eyepiece 20. The image of the specimen is then refocussed by eyepiece 20 to a point at infinity, because modern compound microscopes are designed such that the optical system is properly corrected for infinity focus, since this has long been known to result in the least eye strain upon the observer. However, in he present invention, we desire to sharply focus this image upon a film plane that is not at infinity, but rather is situated at a distance of several feet from the eyepiece. For this reason, a spacer 18 is provided for each eyepiece. The precise thickness of this spacer is determined by the magnification of the eyepiece and the distance of the projection required to properly record the image of the size dictated by the film size that has been selected. For any given eyepiece and projection distance combination, the exact spacer width required can be determined experimentally, by first focussing the specimen sharply while looking through the eyepiece with the unaided eye, and then putting the microsope into the camera apparatus and focussing the image upon the film plane by simply extending the draw tube 19. The distance that the draw tube had to be extended to achieve sharp focus is the correct width for spacer 18, when that particular eyepiece and objective system is used at that projection distance. Failure to use the spacer will mean that the objective must be de-focussed to achieve a sharp image on the film plane. For short projection distances (less than 1 foot) this is critical and image degradation that is noticeable will result.. Fortunately, the effect becomes less severe for the long projection distances that are important for large format photomicrography, and the spacer can be eliminated in making large images, except for the most critical and demanding work, where the highest resolution obtainable is of the utmost importance. The image from eyepiece 20 then propagates vertically upward in the light tight camera neck 24. A light tight seal 22, which may be made of overlapping spirals of black rubber or other suitable material optically isolates the eyepiece and prevents stray light from entering the camera, and couples the eyepiece 20 to the camera neck 24 and insures that the microscope is essentially centered on neck 24 " and therefore is situated essentially on the optical exis of the camera. The spiral rubber seal 22 may be easily parted to facilitate interchange of eyepiece ,20 and spacer 18, which allows magnification adjustment to be accomplished without changing the objective 12 being used and without altering the length of the horizontal arm 28. The beam which exits the eyepiece then propagates vertically upward in camera neck 24 until it reaches mirror 26 that is oriented at a nominal 45 degree angle with respect to the neck. For certain reasons that shall be described later, it is desirable that this mirror be movable between two fixed positions, and this is accomplished by mounting the mirror on a pivot 23 and rotating it between the top and bottom positions of the curved slot 25. The mirror is locked into each desired position by means of the lock screw 27. With this primary mirror in its uppermost position, and with the tertiary mirror 60 lying flat and out of the optical path, the optical beam is deflected horizontally toward secondary mirror 30 and it propagates along the light tight arm 28. When the diverging beam reaches the large mirror 30, which is nominally oriented at a 45 degree angle with respect to the vertical, it is deflected vertically downward toward the base 35 of camera housing main body 32. Resting on the base of camera housing 32 there is a photographic film holder 36 equipped with a dark slide and focus sheet 34. Camera housing 32 may be equipped with a sliding opaque door 38, that can travel up and down in rails 40 and be held in place when in the elevated position by means of lock screws 42. In this embodiment, the photomicroscopist is able to move the film plate holder (or photographic paper easel) 36 around in the projected image so as to frame and crop the picture as he wishes, in much the same manner that the darkroom technician works with the photographic enlarger. The dark slide and focus sheet 34 is painted black on the downward surface and white on the top, and the corners and center of this focus sheet are appropriately marked to aid the photomicroscopist in achieving the best possible large format photomicrograph. In this embodiment, when the door 38 is raised, the operator may insert his head through the door to closely examine the image as it is projected on the focus sheet 34. Simultaneously he may adjust the microscope stage controls 13 and the course focus 16 or the fine focus 14. Since these adjustments are made while viewing the direct projected image on a focus sheet that lies in the same plane the film or paper will occupy when the focus sheet is removed, extremely critical focus may be achieved. Also, it should be mentioned that, in this embodiment, a small format film holder, such as a 4"X5" Polaroid film holder, may be inserted in place of the large film holder 36. This allows a sample of the image to be photographed before the large expensive piece of color paper or film is exposed. This ability to do exact small format test exposure of a small piece of the large format film should result in considerable savings of cost, as very large format color film is quite expensive. Other embodiments may also be constructed in which the camera is entirely sealed, with the film holder rigidly mounted in the camera base with film and focus sheet access through a slot in the side of housing 32 and a view port (not shown) provided in the side of housing 32 could be provided to replace door 38. By properly canting mirror 30, excellent images will still be projected on the white face of focus sheet 34, with the rear of film holder 36 elevated to allow comfortable viewing of the image by a worker sitting in front of the camera. This is of value for in-process high resolution monitoring of microelectronic components. Whenever desired, high quality large format pictures of the microcircuit can be taken by simply removing the focus sheet and activating the shutter. Since the worker is looking at a large image projected on the focus sheet, it is not necessary to hold * the head rigidly above a microscope eyepiece, thereby reducing eye strain, neck strain, and muscle fatigue as experienced now by microcircuit workers. In th,e preferred embodiment there are also certain desirable features built into the camera neck 24. These include a small format camera (or video camera) adapter, referring now to Figure 3, we see a camera adapter tube 79 with bayonet mount 78 and camera 77. This tube 79 is mounted on the port for camera adapter 70. This adapter 70 is of the bayonet mount configuration, and couples to a tube structure 79 that accepts either a standard 35 mm camera, video camera, 2 1/4 X3 1/4 camera, or small format movie camera. The adapter port 70 is equipped with a small positive doublet correcting lens 72 that is precisely contoured to correct for the short projection distance required by the small format devices that will be employed at this port. This adapter port is normally covered by an appropriate opaque cover (not shown) when it is not is use. To use the small format camera port 70 with correcting lens 72, the desired small format photographic camera or video camera is affixed to the port by means of the adapter tube 79 bayonet mount 78. The small mirror 64 is flipped into position by means of lever 67 and it stops at the furthermost position allowed by curved groove 66. Mirror 64 then intercepts the primary beam emanating from eyepiece 20 and reflects it horizontally outward to correcting lens 72 in port 70. Shuttering is accomplished either by means of .the built in focal plane shutters included in small format cameras or it is accomplished electronically in the video camera system. In order to use the camera for large format photomicroscopy, lever 67 is moved to a position that removes mirror (or prism) 64 from the optical beam. With mirror (or prism) 64 removed, the beam propagates vertically upward. It passes through a hole in filter drawer 46, which may be slid out of the neck 24 to be l ' oaded with neutral density filters, color correcting filters, etc. If no filtration is desirable, drawer 46 is simply left empty. The beam then p opagates to shutter 48, which in the preferred embodiment is a conventional iris diaphram type shutter, of which many types are now commercially available. It should be pointed out that in the simplest embodiment, the shutter 48 is simply a sheet of opaque plastic or cardboard that can be slid in and out of the optical beam. In more sophisticated embodiments the shutter 48 used may be a more complex electro-optical device. However, when a simple iris diaphram type shutter is used, it may be activated by a device such as the traditional shutter cable release device 50 illustrated in Figure 2. Above the shutter 48 is a removeable drawer 56 that contains a polarizer 52. When the drawer is slid to the fully "out" position, it is still held by the camera neck 24 but the polarizer 52 is out of the optical beam. When polarization studies are desirable the drawer 56 is slid closed such that the polarizing element 52 is in the optical beam. Of course, for this to be meaningful in accordance with the teachings of modern microscopy, it must be used to analyze the beam of polarized radiation emanating from the spcimen held on slide 13. This is accomplished by mounting a polarizing screen below slide 13 and above condenser 17. To properly analyze the polarized beam emanating from the microscope, provisions must be made to rotate the polarizing element 52. In the preferred embodiment this is accomplished by means of a rotary knob 54 that turns a gear that engages a toothed wheel at the base of the holder for the polarizer 52. In this manner, by simply turning knob 54, detailed analysis of the degree of rotation of the polarization axis of the light that enters the specimen on slide 15 can be realized. Also in neck 24 is a sliding baffle system 57, which can be controlled by means of handles 58 that are external to the neck. These baffles can be used to eliminate any extraneous and unwanted radiation from reaching the film plane in holder 36. Since most photographic formats utilized today are rectangular, these baffles are movable straight edges, constructed of an opaque, plastic or metal material painted flat black. Indeed, to minimize unwanted reflection, the interior of camera neck 24, horizontal arm 28, and camera housing 32 are all painted flat black, although the exterior may be of any color or nature desired. In the preferred embodiment, the structural elements of the camera, comprising the neck 24, arm 28, and housing 32, are constructed of solid opaque plastic, sheet metal, or other suitable fabrication material. The housing 32 must be sufficiently massive and strong to support the weight of the counterbalanced (although smaller) arm and neck along with the required optical elements and desirable photographic components that are housed in the neck, which may even include a beam splitter 68 which deviates a portion of the beam to exposure meter 69. At the top of the neck 24 is mounted a flat mirror 26, which deviates the vertically ascending beam into a horizontal path along the arm 28. Mirror 26 is pivotable in the preferred embodiment, as is mirror 60. When mirror 26 is in its uppermost position and mirror 60 is lying flat against the horizontal base of arm 28, the beam reflected by mirror 26 is deviated into a horizontal path. It propagates directly to mirror 30, which may be protected from dust and particulates when not is use by a sliding dust cover 44. Since both mirrors 26 and 30 are situated at a nominal angle of 45 degrees with respect to the vertical, the beam which strikes mirror 30 is deflected vertically downward by mirror 30 toward the film plane 36 beneath focus sheet 34. If this image is recorded on black and white film, or- reversing media such as is now used in the Polaroid Polacolor ER 8X10 Land Film Type 809, a proper left or right orientation wil be realized in the finished photomicrograph. For most work, such as photomicroscopy of mineral and chemical specimens and most biological specimens, the finished orientation is of no great importance. In other areas, such as photomicroscopy of electronic microcircuitry components, the orientation of the image can be of great importance. If orientation is not important to the photomicroscopist, the preferred embodiment is one in which mirror 26 is rigidly mounted at a 45 degree angle with respect to the vertical and mirror 60 is not included in the camera at all. Operation of this system involves deviation of the beam from the eyepiece onto a horizontal path by mirror 26 until it is intercepted by mirror 30. The beam is then reflected vertically downward until it strikes the film in holder 36 to record a sharply focussed large format image. If left to right orientation is important and it is desired to record the image on standard black and white or colored paper, then it is necessary to use reversing mirror 60 to correct for the number of reflections employed. It is to be noted that an odd number of mirror reflections will give a proper image when viewed directly on the focus sheet or recorded on normal paper, whereas an even number of reflections will give a properly oriented image on reversing media such as that used in the Polaroid film. Hence, in order to obtain a properly oriented image with a standard photographic easel at film holder 36, holding paper such as Ektachrome RC or Cibachrome print material, mirror 60 is rotated into its proper functioning position by moving it counterclockwise until it reaches the end of slot 62. It is locked into place by means of lock screw 61. Mirror 26 is moved by rotating it as far clockwise as is allowed by curved slot 25 and it is locked into position by means of lock screw 27. In this configuration, reversing of the optical path occurs, as is illustrated in Figure 5. The simpler two mirror embodiment is illustrated in Figure 4. It should be pointed out that correct orientation of the image for nonreversing materials can also be achieved by only one reflection as well as by three. Hence an alternate embodiment is envisioned in which the large mirror 30 is removeable (or pivotable) and the image from mirror 26 is projected to the vertical wall of camera housing 32 that may contain an intermediate size (e.g. 8"X10" ground glass or translucent rear projection screen 65). Such an embodiment may have applications in classrooms and microelectronic plants, where it may be desirable to show a high quality image of a particular microscopic specimen or chip to one or more people simultaneously without taking the effort to photograph it. Direct images can easily be taken with a film holder slid into an appropriate mounting position on the interior vertical wall of housing 32 in the same place as was occupied by the ground glass or rear projection screen of the preceding discussion. Although this holder is not shown, the new 8"X10" device for the large format Polaroid sheet film functions well in this embodiment. It is also noted that the entire housing 32 may be mounted on grooved wheels (not shown) that sit on triangular ways 37. This will allow the housing to be adjusted horizontally, provided the camera arm 28 is appropriately configured such that it is capable of telescoping at junction 29. This allows the camera to be moved closer to or farther away from the microscope as is dictated by needs of convenience and the desire to have the ability to make minor adjustments in the resultant magnification without altering either the microscope objective or eyepiece being used. The entire camera and microscope may sit upon a solid common base 74, that is isolated from room vibrations by means of rubber pads 76 on support 75. It should also be mentioned that camera neck 24 may be vertically adjusted by telescoping it at junction 71 and locking it into place by means of lock screw 73. This adjustment allows for variations in height of the microscope 10 and also facilitates interchange of eyepiece 20 and spacer elements 18. The camera structural components, neck 24, arm 28, and housing main body 3"2, are constructed out of a suitable opaque material that is both strong and lightweight, such as modern plastics, and/or sheet metal type materials. The primary optical components of the camera, mirrors 26, 30, and 60, are made out of flat glass suitable polished, silvered, and front surface coated with an appropriate overcoat such as MgF or SiO for protection. However, experience has shown that only slight imperfections can be perceived in the image as a result of ghosting from front surface reflections if the mirrors used are conventional rear surface 1/4" float glass mirrors such as are readily available. Therefore, it is considered acceptable in accordance with the aims and desires of this present invention that mirrors of this type may be utilized in this Folded Optical Large Format Camera System in a low cost configuration. Mirrors 26 and 30 are ideally trapezoidal, although they may be made oval, rectangular or any other shape as long as the full and complete diverging beam is intercepted by the mirror and reflected along the path wherein it ultimately falls upon the film plane in sharp focus. The present camera system may also be embodied in other forms which still retain the spirit and concept of the invention. This includes, but is not limited to, techniques and methods such as the one illustrated in Figure 6. In this embodiment, the microscope, folded optical system and photographic recording medium are all housed in a single structure, rather than employing a camera based upon the concepts of the main body housing, camera arm, and camera neck configuration as has been described. Referring now to Figure 6, microscope 10 with illumination means 83 is sitting on the base of a large housing 85 that is constructed of opaque sheet metal, plastic, or other suitable construction material. Guide ways 82 of appropriaate width to receive the base of the microscope enable the microscope to easily be positioned and repositioned in exactly the same place with respect to the base 90 of the housing. A baffle sytem 81 is erected around the microscope to prevent stray light emanating from source 83 from -reaching either mirror 30 or film plane 34. The baffle 81 is constructed of suitable structural material to be opaque to visible light and to afford adequate mechanical support for any or all of the optical components which have been previously described as being housed in the ' neck of the camera in the preferred embodiment. Shown in Figure 6 is only the shutter 48, connected to a long shutter cable release 50 which allows the shutter to be activated from outside housing 85. Baffle system 81 consists of three vertical panels joined at the seams and a top (with hole 97, through which the beam may pass) so as to form a box without a front panel. With sliding door 38 in the up position, the operator can make necessary changes of specimen, focus or lighting conditions as he desires to the microscope through the open front of baffle 81. When door 38 is closed by means of handle 80 the inner surface of door 38 forms the front panel of baffle 92. Baffle 92 now has the form of a completely enclosed box with a hole 97 in its top through which the light beam from microscope 10 propagates vertically upward toward mirror 26. This mirror is mounted to structural elements within the interior of housing 38. The light beam is then deflected horizontally outward to mirror 30 which then deviates it vertically downward to focus sheet 34. Sheet 34 covers the film in film holder 36 except during times of exposure. Door panel 38 may be closed by means of handle 80 during exposure of the image. The purpose and function of door panel 38 is of course to keep unwanted external radiation from fogging the film or degrading the picture. Panel 38 can be omitted if the camera is to be used in a darkened room. Also, any number of other reasonable methods may be employed to accomplish its intended purpose. The Folded Optical Large Format Photomicrographic Camera System may be modified so that it may be used as a device for producing mfcrophotographs , microdots, or microscopic images on photoresist material for the fabrication of microelectronic components. In this alternative embodiment, the optical path through the camera is totally reversed. Looking now at Figure 7, the subject to be photographed (original copy) 84 is placed in the position normally occupied by the focus sheet 34 (Fig 2) and uniformly illuminated by an extended internal light source 86. If the originals are in the form of transparencies or photographic negatives, good uniform illumination may be achieved by replacing film holder 36 with a light table 86. Such an extended internal light source may be produced by mounting a sheet of ground glass or translucent plexiglass above fluorescent light tubes. The light from a diffusely illuminated transparency placed upon the top surface of such a light table will then travel upward in the main body housing until it is reflected by secondary mirror 30 toward primary mirror 26. Thence the beam is deflected downward to eyepiece 20 and thence to microscope objective 12 which focusses it to a sharp image in the focal plane of the objective 12. In this embodiment, instead of microscope slide 15 we utilize high resolution photographic plate 85 with its emulsion side upward. If no precautions are taken to protect the photographic plate (by means such as a baffle around the plate connecting it with the objective), the microphotographs should be recorded in a darkened room to prevent undesirable fogging of plate 85. The objective is sharply focussed on the emulsion surface of the photographic plate and an image is recorded whenever the shutter 48 is activated. By moving the photographic plate by means of stage control 13, a great many microphotographs can be recorded on the same photographic plate 85. After normal photographic development, minute images on the plate 85 may be viewed by means of the camera used in its normal "way. Full size hard copies may be obtained at any time by simply producing a large format photomicrograph utilizing the earlier-described embodiments of the invention. A microphotO'graph of a positive print may also be produced by placing the print on the camera base and providing uniform illumination from an external source. This can take the form of a beam projected through doorway 38, or by reflecting the light . beam from beamsplitter 68, introduced through a port " (not shown) in camera neck 24 opposite light meter 69. This light beam then travels upward to mirror 26 which then deviates the beam horizontally along camera arm 28 to secondary mirror 30 which deflelcts the light downward to illuminate the print held in the film holder or easel 36. This light reflected by the positive print travels backward through the optical train to form a microphotograph in the focal plane of objective 12 on the photographic plate 85 held by the stage. It is also possible to replace the film holder 36 with a video monitor and produce a microphotograph of an image displayed on the monitor. In Figure 15, the embodiment of the invention shown in Figure 7 has been modified to show a video display monitor 96 with screen 94 in the position occupied in Figure 7 by light table 86 covered by original copy 84. Any image displayed on screen 94 of video display monitor 96 can now produce a microscopic image (microphotograph) onto the sensitized material on the stage of the microscope. Since the microscopic image can be recorded on any light sensitive medium placed in the focal plane of objective 12, this may take the form of photoresist materials such as are used in the production of microelectronic components. Microphotographs can also be produced with a camera in the small format camera port 72. This is accomplished by mounting a transparency or negative in the film plane of the camera 77 and mounting a ground glass or translucent sheet of material behind the transparency. A flood light, flash, or other suitable light source is then used to produce the microphotograph when the shutter of the camera is activated. As described before, the photographic film, photographic plate, photoresist or other light sensitive medium is mounted with its emulsion side up in the focal plane of objective 12 for the particular system used. Figure 8 shows a perspective view of an additional embodiment of the photomicrographic camera system, a modification to a Micro " Display Monitor 100. The monitor 100 provides a large format, high resolution real time display of microscopic specimens of excellent color fidelity. It is envisioned that the primary use of this invention will be in the on-line inspection of wafers, chips, and other micro-electronic components at various stages in their fabrication and QC monitoring processes, as well as a valuable tool in the classroom, laboratory or hospital environment. Although the primary mode of operation of the device is for the provision of real time displays of photomicrographic specimens, it is also possible to produce high resolution, large format photomicrographs in color or black and white at any time. In an alternate embodiment, the large photomicrographic image can be digitized for immediate computer processing and enhancement of the photomicrographic image or for transmission via telecommunication links to distantly located experts. Fig. 2 disclosed that mirror 30 (which is normally configured at 45 degrees with respect to the front face of the camera) can be pivoted or removed so that the large image could be viewed on a ground glass or other suitable rear projection screen. This has the disadvantage of placing the image away from the microscope and in a position so that it can not be easily viewed by an inspector or by a group in front of the camera. Micro Display Monitor 100 overcomes this disadvantage of the camera system shown in Fig. 2. For the micro display monitor 100 shown in Fig. 8, the secondary mirror 102 held by brackets 103 is situated at a nominal angle of 45 degrees (see Fig. 9) with respect to the top surface 104 of the camera housing 106, such that the image is formed by light rays 107 on a high resolution screen 108, which is situated in the front face 110 of the camera housing. The screen 108 is mounted in a spring loaded holder frame 112 to permit a film holder 114 (Fig. 12) to be inserted when it is desired to take a high resolution photomicrograph of the image. A light guard 116 is provided to protect the screen 108 from overhead illumination and to provide greater visibility for viewing in a lighted room. In an alternative embodiment shown in Fig. 10, mirror 102 is rotated 45 degrees about a vertical axis, tilted forward 45 degrees about a horizontal axis and held in this position by brackets 105. Light rays 107 are thus directed downward to produce the image at the base when larger format photomicrographs are desired. Film holder 117 is held in brackets 118 mounted in the base of this embodiment. Film holder 117 may be installed and removed through light-tight access port 120 in the front face 110 of the camera housing. When film is being exposed in the base of monitor 100, an opaque sheet 115 is placed in holder frame 112 in the normal place of film holder 114 behind the translucent screen 108 to produce a light-tight configuration (see Fig. 12). Fig. 11 is a side elevation of the holder frame 112 showing rear projection screen 108 within frame 112. Fig. 12 is an end view of holder frame 112 showing both screen 108 and film holder 114 biased tightly in position against the back of frame 112 by springs 120. When film holder 114 is removed, springs 120 push screen 108 tightly against the back of holder frame 112. Also, film holder 114 may be replaced with an apaque screen 115, particularly when the film holder 117 is being used to expose film at the base of camera housing 106 and a light-tight configuration is desired. Screen 108 is a high resolution, rear projection screen. It may be a fine ground glass screen, frosted mylar on glass, or other commercially available rear projection' material. The image produced is not only of high spatial resolution but it has true color fidelity. This is of tremendous importance in the semiconductor industry, where the subtle variations in color constitute quantitative evidence of the thickness of oxide and nitride layers on the wafer, metallization layers, etc. Since video systems are subject to color drift and their colors are alterable at will, the Micro Display Monitor is superior to this type of prior art. The large heads-up display allows the worker to view a large real image of the specimen, rather than a virtual image as is seen when one looks in the eyepiece of a microscope. This makes it possible to view the image from many positions, and it is not required that the head and eyes be maintained in any one position as is required by the prior art. This avoids many problems of neck and back strain, eye strain, headaches, fatigue, etc. It should allow workers to perform their tasks over much longer periods of time with far greater comfort and higher efficiency. This also allows many people to view the same image simultaneously. Hence, the supervisor can easily verify if the technician is inspecting the proper area of the wafer. Also, since the image is large and real, one can simply point to an area of interest while discussing it with others. The Micro Display Monitor is also superior to another aspect of the prior-art which is embodied in the technology of the "conference microscopes". The conference microscope uses an array of beam splitters and tubes to connect several separated microscope heads with binocular eyepieces to the objectives on a single master microscope. The person using the master microscope moves and focusses the specimen for his eyes, while everyone views the image. He has available a small illuminated pointer that can be used to point to a desirable feature on the specimen, and the others see the pointer as well. Typically only 4 to 8 additional viewers can look at once. Since individual eyes differ, there is • no way of knowing for certain that any particular individual is seeing the same image plane in sharp focus. With the Micro Display Monitor, it is possible to use a screen large enough that it could be viewed by a group or an entire classroom at once. There are also applications envisioned for the large format camera-micro display monitor in which it will be desirable to digitize the photomicrographic image. Since the initial image is large, the resolution will not be limited by the pixel size of currently available solid state detectors, such as Charge Coupled Devices (CCD's) or Multi-Anode MicroChannel Arrays. The primary uses of this technology may lie in the medical and petroleum geology fields as well as microelectronics. The optics of the system remain unchanged, but the film holder is replaced with a similar plate which holds the solid state detector. The image is viewed on a TV monitor. The large group image that is produced by the camera system is not degraded by the size of the pixels as is normally encountered when a video camera is simply adapted to a microscope. It is already possible to manufacture 5 inch diameter Multi-Anode MicroChannel Array devices of 30 micron pixel size. This should permit images with sub- micron features of the original specimen to be recorded with a VCR or transmitted via telecommunications links to distant localities. This would allow physicians and surgeons and pathologists to confer with distantly located experts while all view the same microscopic image of a tissue section, bacteria, etc. Changes in the focus and specimen position would instantly be observed by all. This would also allow petroleum geologists at distant field locations to confer in real time with bistratigraphers and micropaleontologists. This would avoid the delay of transmitting the specimens by 'mail and eliminate the danger of possible loss of valuable time and materials. It is also possible to adjust the configuration and placement . of the transfer mirrors so as to render a large-format display that is slightly tilted inward or outward, as desired. It has already been noted that it may be necessary to alter the number of reflections to achieve the proper right or left orientation depending upon whether the viewer is observing the image on a rear projection screen or on positive or negative film material. In an alternative embodiment shown in the diagrammatic side view of Figure 13, Mirror 26 is configured and arranged to slide laterally so as to intercept light rays 107 when in a first position and to retract to a second position out of the line of light rays 107. When mirror 26 is retracted to the second position, light rays 107 hit mirror 122 which is configured as a 45 V-shaped wedge having reflecting surfaces 124 and 126, which are located directly behind the first position of mirror 26. In this case, light rays 107 hit first reflecting surface 124, are reflected to second reflecting surface 126 and are then reflected to secondary mirror 102. Fig. 14 is a plan view of the micro display monitor of Fig. 13, showing how the primary mirror 26 having one reflecting surface may be moved laterally to allow use of the primary mirror 122 having two reflecting surfaces 124 and 126 (shown in Fig. 13). Knob 128 may be pulled to move mirror 26 to its second (inactive) position, as shown in Fig. 14, thus causing the proper orientation for direct imagery or photomicroscopy on positive or negative films. With mirrors 26 and 122 in this configuration, no shift in image position will occur when knob 128 is used to change mirrors. If we desire the image size to undergo no change when we alter the left to right orientation of the image, mirror 124 is mounted below mirror 26 so that the path length of the light ray 107 is constant when mirror 124 is removed from the beam. As herein described, the present invention is a photomicrographic camera system and real time display monitor which is simpler, less expensive to manufacture, easier to adjust, and which provides greater mechanical stability than the commercially available vertical cameras which have been state of the art for the industry. Moreover, this invention conveniently provides the capability of handling very large format film sizes of the order of 16"X20" or larger. Ordinary vertical cameras could not handle these formats in a room with eight foot ceilings. Moreover, one person could not focus the image since to do so, he would have to be up on a stepladder to see the image closely and thus would be out of reach of the microscope focussing controls. Since the image falls onto the photographic material or rear projection display screen immediately beside the microscope, it is very easy for the worker to achieve critical focus by looking directly at the projected image while his hand controls the focus knobs 14 and 16 and/or stage translation knobs 13 of his microscope. None of the many possible embodiments obviate the basic concept and purpose of this invention, namely the use of a folded optical system employing flat mirrors, or prism and flat mirror combinations to deviate the light beam emanating from a microscope in such a manner that it propagates vertically downward to the film plane. This enables the forces of gravity to work for the large format camera rather than against it. The film holder is rigidly held in place on the supporting base rather than vibrating and creeping downward and the film or paper material is flattened out rather than bulging downward and trying to fall out of the easel or film holder. Also the folding of the light beam allows a very compact camera to produce images of vastly greater sizes than could be accomplished with devices based upon the art and invention of Flint et al. As explained in detail above, the preferred embodiment of this invention can be modified slightly so that is may be used to produce microphotographs, microdots,, or microscopic images on photoresist material to produce microelectronic components. To do so, the optical path through the device is reversed. As shown in Fig. 7, the item to be photographed 84 is placed in the position of focus sheet 34 (Figure 2) and illuminuated by a light table 86 or other external light source. Microscope slide 15 is replaced by a high resolution photographic plate 85 with its emulsion side upward. After sharply focussing the image with the objective, the image is recorded by the shutter 48. Thus, the device may be utilized as a simple and highly effective method and apparatus for producing microdots or microelectronic circuits. What is claimed is:

Claims: CLAIMS 1. A micro display monitor system comprising: a microscope having an objective, a stage and an eyepiece; a camera housing comprising: a main body, said main body comprising an enclosure having a flat base, a flat top and four lateral faces, including a front face, a horizontal arm section connected to the top side of said main body and extending laterally therefrom, a vertical neck section attached to said horizontal arm section and suspended over said microscope and covering said microscope eyepiece; a primary mirror located in the junction of said neck section and said arm section, directly above said microscope, said mirror being oriented . at substantially a 45 angle with respect to the vertical, said mirror being arranged to be able to receive a vertically ascending and diverging light beam amanating from said eyepiece of said microscope and deflect it horizontally along the long axis of said arm; a secondary mirror located in the top of said camera housing main body, said mirror being oriented at substantially a 45 angle with respect to said front face, so as to receive said light beam from said primary mirror and deflect it toward said front face; a shutter arranged to interrupt said light beam; a rear projection screen mounted on the front face of said camera housing main body, said screen being positioned to receive light rays from said secondary mirror. 2. The micro display monitor system of claim 1 wherein said rear projection screen is mounted in a spring-loaded holder frame. 3. The micro display monitor system of claim 2 wherein said holder frame is arranged with an opening on its side for receiving a film holder behind said rear projection screen, whereby a film holder may be inserted behind said screen, thus pushing said screen forward, in order to expose film in the viewing plane of said screen. 4. The micro display monitor system of claim 3 comprising a light guard attached to said holder frame for protecting said screen from overhead illumination so as to provide greater visability for viewing in a lighted room. 5. The micro display monitor system of claim 4 comprising: auxiliary holders for said secondary mirror, said auxiliary holders being mounted in said camera housing, said holders being positioned so as to orient said mirror at substantially a 45 angle with respect to the surface of said flat top, so as to receive said light beam from said primary mirror and deflect it downward; a film holder resting on said base of said camera housing main body below said secondary mirror and positioned to receive an image carried by said light beam; a film mounted in said film holder. 6. The micro display monitor system of claim 5 wherein said primary mirror is arranged to retract to a second position out of the line of light rays from said microscope. 7. The micro display monitor system of claim 6 comprising a second primary mirror mounted in the junction of said neck section and said arm section, immediately behind said primary mirror, said second primary mirror being configured as a V-shaped wedge having two reflecting surfaces mounted at a 45 degree angle to each other, whereby selective use of said second primary mirror will cause the proper orientation for direct imagery or photomicroscopy on positive or negative films. 8. A method of producing microphotographs or microdots by use of a microphotographic camera system with shutter, primary and secondary mirrors, and an extended internal light source, and including a microscope equipped with an eyepiece, stage, and objective comprising: positioning a transparent original copy onto the top surface of said extended internal light source; illuminating said original copy by said extended internal light source such that the light which passes through said original copy is reflected from said secondary mirror to said primary mirror and enters said eyepice of said microscope to form an image in the focal plane of said objective; ■ placing a high resolution photographic sensitized material on tire stage of said microscope; focussing the objective of said microscope onto said photographic sensitized material; and operating said shutter of said camera system to record an image of said original copy on said photographic sensitized material. 9. The method of producing microdots of claim 8 wherein said original copy is a pattern generated on the face of a video display monitor which is mounted in place of said original copy illuminated by said extended internal light source. 10. The method of producing microdots of claim 8 wherein said original copy is translucent rather than transparent.

Inventors: HOOVER RICHARD BRICE, HOOVER, RICHARD, BRICE
Applicants: MICROMEGA CORP, MICROMEGA CORPORATION
Application year: 1986
Main classification: G03B15
IPC codes: G03B15, G03B17