A virtual computer monitor is described which enables instantaneous and intuitive visual access to large amounts of visual data by providing the user with a large display projected virtually in front of the user. The user wears a head-mounted display containing a head-tracker, which together allow the user to position an instantaneous viewport provided by the head-mounted display at any position within the large virtual display by turning to look in the desired direction. The instantaneous viewport further includes a mouse pointer, which may be positioned by turning the user""s head, and which may be further positioned using a mouse or analogous control device. A particular advantage of the virtual computer monitor is intuitive access to enlarged computer output for visually-impaired individuals.

The invention relates to human/computer interfaces to visual data and more particularly to systems that must display a larger amount of visual data than may be conveniently displayed in a single conventional computer monitor. The present invention uses virtual reality techniques to provide instantaneous and intuitive access to large fields of visual data, and to provide visually-impaired users with enhanced access to enlarged visual data.
Among the visually-impaired population, the most common approach to computer access is specialized software. and/or hardware that enlarges the image displayed on the computer monitor. This is because simpler solutions such as moving closer to the monitor, using a larger monitor, adding an optical screen magnifier, or using a spectacle-mounted telescopic system provide either limited magnification or a very limited viewing field. Examples of commercially-available screen enlargers include LP-DOS by Optelec (Westford, Mass.), Zoomtext by Ai Squared (Manchester Center, Vt.), MAGic by Microsystems Software (Framingham, Mass.), and Magnum by Arctic Technologies (Troy, Mich.). In addition, simplistic screen enlargement modules are included in both the Microsoft Windows and Apple Macintosh operating systems.
These conventional computer display magnification solutions operate by magnifying the original image of a software application""s output to a xe2x80x9cvirtual pagexe2x80x9d whose size is much larger than the physical monitor. For example, with a magnification of 10, a standard 8.5xe2x80x3xc3x9711xe2x80x3 page would be approximately 7 feet wide by 9 feet tall. The visually-impaired user then operates the computer by using a mouse, joystick, or cursor keys to control which portion of the virtual page is shown on the monitor at any given point in time. Since the monitor is fixed, the user is in essence moving the virtual page across the monitor, in a manner analogous to that used in closed-circuit television (CCTV) systems for magnifying book pages.
In most cases, conventional screen magnification is performed completely in software running on the host computer""s central processing unit (CPU). While this provides a very low-cost solution, the data to be shown on the display must be rendered in its entirety whenever the user pans to a new location within the enlarged image. This can result in lags between commanding the computer to pan and seeing the new image. To overcome this problem, the entire virtual image can be rendered and stored in a video display buffer. Then, as the user selects a portion of the image for viewing, the required portion of the data can be quickly read out of the display buffer and sent to the display device. An example of such a hardware-accelerated screen magnifier is the Vista by Telesensory, Inc. (Mountain View, Calif.). This technique is a form of hardware acceleration known as image deflection.
Unfortunately, there are two basic shortcomings to the conventional approach, even with hardware acceleration. The first problem is spatial orientation, in that it is difficult to determine where on the page one""s view is directed at any given time. This occurs because the monitor does not move, and there are no other visual cues to indicate where on the virtual page one""s line of sight is facing. This spatial orientation problem is exacerbated for high magnifications and for portable systems employing small display monitors. For example, one study (Goodrich, et. al.) found mean magnifications of 15.48xc3x97for nearly 100 experienced users of closed-circuit television devices. At 15xc3x97, a 15xe2x80x3 monitor can only display about 1% of a standard 8.5xe2x80x3xc3x9711xe2x80x3 page, making most computer work essentially impossible for such users. The problem is further exacerbated by the emergence of graphically-intensive computing regimes such as Microsoft Windows and the Internet World Wide Web, where individual graphic elements may be magnified to become larger than an instantaneous viewing window, or may be automatically generated outside of the user""s instantaneous viewing window without the user""s awareness.
The second fundamental problem in the conventional approach is dynamic control, in that all of the various control schemes for navigating about the page are cumbersome, confusing, and slow. This is because the navigation methods are unintuitive, relying on such logic as xe2x80x9cuse joystick to move cursor around screen, and when cursor reaches the edge of the screen, the next portion of document in that direction will be displayed.xe2x80x9d Alternatively, some screen enlargers maintain the cursor at the center of the screen, and require the user to position a desired insertion point over the cursor by moving the entire virtual page with a mouse or joystick. In all cases, dynamic control is not only unintuitive, but requires use of at least one hand, which negatively impacts productivity, and may make use by physically-impaired users difficult or impossible.
Together, these spatial orientation and dynamic control problems were termed the xe2x80x9cfield navigationxe2x80x9d problem in the National Advisory Eye Council""s 1994-98 National Plan (Legge, et. al.), in which the Low Vision and its Rehabilitation Panel identified this area as a particularly promising opportunity for new technologies.
One promising new technology that is now maturing is virtual reality, which is typically defined as a computer-generated three-dimensional environment providing the ability to navigate about the environment, turn one""s head to look around the environment, and interact with simulated objects in the environment using a control peripheral.
In a virtual reality system, the user is xe2x80x9cimmersedxe2x80x9d in a synthetic environment, in which virtual objects can be located anywhere in the user""s physical space. The user views these objects by wearing a head-mounted display (HMD), which uses an optical system to cause a tiny display source such as a cathode ray tube or liquid crystal display to appear as a large display screen several feet in front of the user. Since the display source (or sources in the case of two eyes) is fixed to the user""s head, the display is viewable regardless of where the user points his line-of-sight. The user also wears a head-tracker, which senses the direction the user is facing, and sends this information to the host computer. The computer uses this data to generate graphics corresponding to the user""s line of sight in the virtual environment. This approach to human/computer interfaces was first conceived by Ivan Sutherland in 1966 for use in military simulators, and was first commercialized in the form of the Eyephone head-mounted display by VPL Research in the late 1980s.
Prior art in this area includes a wide range of relevant patents describing low-vision aids, improved virtual reality systems and components such as HMDs and head-trackers, but none which embody or anticipate the present invention.
In the field of low-vision aids, U.S. Pat. No. 4,227,209 issued Oct. 10, 1980 discloses an electronic sensory aid for visually-impaired users including an image sensor and a display array, wherein the degree of magnification provided in the display array may be adjusted by changing the number of display elements corresponding to each sensor array element. For use in electronic sensory aid applications requiring a large depth of focus, an improved image capture approach is disclosed in U.S. Pat. No. 5,325,123 issued Jun. 28, 1994, in which the imaging camera includes an opaque stop with a small aperture, thus allowing the magnification to be adjusted by moving the camera towards or away from the object to be magnified. A non-electronic sensory aid is disclosed in U.S. Pat. No. 4,548,485 issued Oct. 22, 1985, in which an XY stage is used to move textual material across an optical viewing system that captures a portion of the textual material for enlargement.
In U.S. Pat. No. 5,125,046 issued Jun. 23, 1992, and U.S. Pat. No. 5,267,331 issued Nov. 30, 1993, an improved imaging enhancer for visually-impaired users is disclosed in which an image is captured, digitized, and electronically enhanced to increase contrast before displaying the imagery. An improvement to this approach using a head-mounted display is disclosed in U.S. Pat. No. 5,359,675, issued Oct. 25, 1994.
In the field of virtual reality systems, U.S. Pat. No. 5,367,614 issued Nov. 22, 1994 to Bisey discloses a three-dimensional computer image display system using an ultrasonic transceiver head-tracking system to control a three-dimensional display to cause the image to change its perspective in response to head movements. In addition, U.S. Pat. No. 5,442,734 issued Aug. 15, 1995 to Murakami discloses a virtual reality system incorporating a head-mounted display, head-tracker, and image processing system in which predictive tracking algorithms are used to differentially update portions of the display field to provide more rapid updating of those portions of the display field corresponding to the center of the user""s visual field. In U.S. patent application No. 07/621,446 (pending) filed by VPL Research, Inc., a virtual reality system is disclosed in which spatialized audio cues are generated to provide real-time feedback to users upon successful completion of manual tasks such as grasping virtual objects using a sensor-laden glove input device.
In the head-mounted display field, U.S. Pat. No. 5,003,300 issued Mar. 26, 1991 to Wells discloses a raster-based head-mounted display that may be used to display an image to either eye. U.S. Pat. No. 5,151,722 issued Sep. 29, 1992 to Massof discloses a video-based head-mounted display featuring a unique folding optic configuration so that the device may be worn like a pair of glasses. U.S. Pat. No. 5,281,957 issued Jan. 25, 1994 to Schoolman discloses a portable computer system incorporating a head-mounted display that may be hinge-mounted to an eyeglass frame so that the display may be folded up out of the way for viewing the physical environment. A wide variety of additional patents in the area of specific design improvements for head-mounted display devices exists, however, the specific head-mounted display design approach employed to effect the present invention is not critical, so long as image quality, brightness, contrast, and comfort are maintained at high levels.
In recent years, there have been several attempts made to apply head-mounted displays to the problems of enhancing imagery for visually-impaired users. One such effort has resulted in the Low-Vision Enhancement System LVES) developed by Johns Hopkins University and marketed commercially by Visionics (Minneapolis, Minn.). The LVES device incorporates a head-mounted display with integrated cameras and an image processing system. The cameras generate an image of whatever is positioned directly in front of the user, and the image processing system enlarges the image and performs enhancement functions such as contrast enhancement. While the LVES device can provide magnified imagery of real-world objects to some visually-impaired users, it suffers from several shortcomings compared to the present invention. First, the LVES does not incorporate a head-tracker to provide a hands-free means for navigating within computer data. Further, the LVES suffers from a jitter problem exactly analogous to that experienced by users of binoculars or telescopes. In simple terms, any jitter in the user""s line-of-sight is magnified by the same factor as the imagery, which causes the image provided to the user to appear unsteady.
U.S. Pat. No. 5,109,282 issued Apr. 28, 1992 to Peli discloses a novel image processing method for converting continuous grey tone images into high resolution halftone images, and describes an embodiment of the method applicable to presentation of enlarged imagery to visually-impaired users via a head-mounted display. In this device, the imagery is generated by a conventional camera manually scanned across printed text as is common in closed-circuit television systems for the visually-impaired. The head-mounted display is a Private Eye by Reflection Technologies (Waltham, Mass.), which employs a linear array of light-emitting diodes converted to the impression of a rectangular array by means of a scanning mirror. In the disclosed device, benefits of using a head-mounted display for low-vision access to printed material in portable situations are discussed, including the larger visual field, higher visual contrast, lighter weight, and smaller physical size provided by an HMD compared to a portable conventional television monitor. However, no connection to a computer for viewing computer-generated imagery is disclosed or anticipated, and no incorporation of a head-tracking device is disclosed or anticipated.
In the tracker art, a variety of tracking approaches and applications have been conceived and constructed. U.S. Pat. No. 5,373,857 issued Dec. 12, 1994 to Travers, discloses a head-tracking approach for the yaw degree of freedom in virtual reality applications consisting of a magnetic sensor disposed on a headset to produce a displacement signal relative to angular displacement of the head set with respect to the earth""s magnetic field. A more sophisticated approach has been developed by the Massachusetts Institute of Technology (MIT), in which an analogous magnetic sensor is used to correct drift in a much faster differential sensor such as an accelerometer, which sensors together provide extremely rapid response and high accuracy within a single package. The MIT approach, believed to be patent-pending, additionally incorporates differential sensors to detect changes in the pitch and roll degrees of freedom, which sensors may also be corrected using slower absolute sensors such as liquid-filled capacitive tilt sensors.
Also within the tracker art, a number of devices have been disclosed which sense head movement for purposes of controlling positioning of a cursor or mouse pointer within the viewable portion of a conventional display monitor. U.S. Pat. No. 4,209,255 issued Jun. 24, 1980 to Heynau discloses a system for pilots employing a light-emitting diode mounted on the pilot""s head, with photodiodes located on the display to sense the tapered energy field from the light-emitting diode for purposes of determining the pilot""s aimpoint within the display.
U.S. Pat. No. 4,565,999 issued Jan. 21, 1986 to King discloses a cursor control system for use with a data terminal wherein a radiation source and a radiation sensor are used to determine changes in a user""s head position for purposes of controlling cursor position on the screen.
U.S. Pat. No. 4,567,479 issued Jan. 28, 1986 to Boyd discloses a directional controller for video or computer input by physically-impaired users consisting of a series of mercury switches disposed in proximity to a user""s head, wherein movements of the user""s head are sensed and converted into cursor control commands. This device also employs a pressure switch activated by the user""s mouth which can provide a further control signal such as that generated by clicking a mouse button.
U.S. Pat. No. 4,682,159 issued Jul. 27, 1987 to Davison discloses an apparatus and method for controlling a cursor on a computer display that consists of a headset worn by the user, and a stationary ultrasonic transmitter for emitting sound waves which are picked up by receivers in the headset. These sound waves are compared for phase changes, which are converted into positional change data for controlling the cursor.
U.S. Pat. No. 5,367,315 issued Nov. 22, 1994 to Pan discloses an infrared-light based system that indicates head and eye position in real time, so as to enable a computer user to control cursor movement on a display by moving his or her eyes or head. The device is intended to emulate a standard mouse, thereby allowing use of the presently available software and hardware.
While the above examples demonstrate a well-developed art for controlling computer cursors via head movement, none disclose or anticipate application of head-controlled cursor movement within a head-mounted display, and none anticipate an approach such as the present invention wherein the cursor remains fixed at a particular position within the display while the displayed data is moved instead of the cursor. Movement of displayed data within a head-mounted display in response to head movement has heretofore been used only within virtual reality systems designed for simulating sensory immersion within three-dimensional computer simulations. In such applications, cursors or mouse pointers are not controlled by head movement, but are generated when required through the use of a separate hand-controlled input device.
While virtual reality is still a developmental technology involving exotic graphics hardware, specialized software, and long integration cycles, the concept of closing a control loop between head-tracker data and HMD imagery can be implemented analogously for viewing arbitrary computer data instead of specially-constructed virtual environments. For normally sighted individuals, this could be beneficial by providing a large virtual computer desktop surrounding the user, which can provide simultaneous access to a larger amount of visual data than is possible using the small virtual desktops currently provided on common computing platforms such as Macintosh and Windows. For visually-impaired individuals, head-tracked HMD display techniques can be used to conveniently access a magnified virtual page, and thus enable productive computer use by nearly 1,000,000 new users.
It is therefore an object of the current invention to solve the field navigation problem by combining virtual reality display techniques originally developed for military flight simulators with screen magnification techniques, in order to create a novel and intuitive display interface for visually impaired users.
It is another object of the current invention to provide an intuitive computer display interface allowing the user to automatically achieve proper spatial orientation by directly coupling the user""s head orientation to the displayed portion of a magnified virtual page.
It is a further object of the current invention to provide an intuitive portable computer display interface allowing the user to automatically control the position of a cursor or mouse pointer on a computer-generated virtual page by directly coupling the user""s head movements to movements of a cursor across the virtual page, thus freeing the user""s hands for other tasks.
It is an additional object of the present invention to provide hands-free instantaneous selection from between many concurrently active computer applications by changing one""s line-of-sight from one application window""s virtual location to another.
It is yet another object of the present invention to provide and maintain a cursor at a user-selectable position within the user""s field-of-view, in order to support use of the virtual computer display by users with arbitrary, non-central preferred retinal loci.
It is still another object of the present invention to alert the user to events occurring outside of the user""s instantaneous field-of-view through the use of spatialized audio alerts perceived to originate from the direction of the event, thus causing the user to turn and look in the direction of the event.
It is yet a further object of the present invention to provide effective operation at magnifications much greater than those possible using fixed monitors, by using a novel technique known as spatial compression.
It is still another object of the present invention to provide improved scrolling of imagery across the user""s field-of-view, through application of smoothing, thresholding, prediction, and drift compensation algorithms to improve response to raw data representing the user""s instantaneous line of sight.
It is still a further object of the present invention to provide a computer display for visually-impaired users that is convenient, lightweight, low-cost, minimally power hungry, and capable of portable operation without degraded performance.
It is another object of the present invention to provide a means for visually-impaired users to view enlarged video imagery in real time over an expanded field-of-regard, thus reducing jitter compared to head-mounted closed-circuit television systems.
In accordance with the present invention, there has been devised a xe2x80x9cvirtual computer monitorxe2x80x9d (VCM) which is broadly comprised of a head-mounted display means worn by the user, a head-orientation sensing means worn by the user, and software means for interfacing these devices to a host computer such that the user""s head orientation data is processed to determine which portion of an arbitrary software application""s output imagery to display. By properly matching the angle of head rotation to the extent of scrolling across the magnified image, the image can be made to appear fixed in space. The particular location of the portion of the virtual image which is actually being seen by the user is dependent upon the direction in which the user looks. As the user looks to the right, the portion of the virtual image being seen by the user is to the right of the portion of the virtual image previously being seen by the user. Similarly, as the user looks up, the portion of the virtual image being seen by the user is above the portion of the virtual image previously seen by the user. Upon initialization of the VCM device, the user triggers calibration between the user""s straight-ahead line of sight and the center of the virtual page. From then on, the user can rotate her head left, right, up, and down to visually scan across the page in corresponding directions. The overall impression is analogous to a normally sighted person scanning across a newspaper page.
As applied to a computer interface device for the visually-impaired, the VCM software provides a magnification adjustment to allow each user to achieve adequate visual resolution without needlessly reducing his instantaneous viewing field. The software also provides a cursor, which nominally remains positioned at the center of the HMD physical field regardless of head movements so that the cursor can be positioned anywhere upon the virtual page by turning to face that location. A further adjustment allows setting the fixed cursor location to any arbitrary position in the HMD device""s physical field, so that users with unusable portions of their visual fields can select an alternative preferred retinal loci instead of the center. A software selection also provides an overview display, which shows a reduced-magnification image of the entire virtual page, with a bold black box highlighting the outline of the instantaneous field within the entire field.
An additional important feature is the ability to temporarily adjust the cursor position in real-time using a controller peripheral such as a joystick or mouse. This feature allows fine positioning of the cursor within the field by temporarily locking the head-tracking system to freeze a portion of the virtual page on the physical display, while the controller is used to move the cursor in small increments.
An additional important feature is the ability to display image components in addition to the cursor at fixed points in the physical display, which allows menus or other icons to remain in the user""s instantaneous viewing field at all times while scrolling across image content.
An additional important feature resides in the ability to reduce the lag between a head motion and display of the new direction""s image by using image deflection, thresholding, smoothing, prediction, and a novel drift compensation technique to reduce display xe2x80x9cswimmingxe2x80x9d, which is caused whenever imperfect head orientation sensing causes the displayed image to not appear fixed in real-space.
An additional important feature resides in the ability to magnify images by extremely large factors using spatial field compression, where the displayed image is scrolled across the physical display at a faster rate than the head is turned. This enables use by individuals with limited head motion, and allows magnification to levels that would otherwise require turning completely around to view edges of the image.
An additional important feature resides in the use of a partially immersive HMD, which avoids simulation sickness by allowing the user to maintain a constant frame of reference in the physical world since real objects can be seen around one or more edges of the display.
It is therefore an advantage of the current invention that it solves the field navigation problem by combining virtual reality display techniques originally developed for military flight simulators with screen magnification techniques, in order to provide a novel and intuitive display interface for visually impaired users.
It is another advantage of the current invention that it provides an intuitive computer display interface allowing the user to automatically achieve proper spatial orientation by directly coupling the user""s head orientation to the displayed portion of a magnified virtual page.
It is a further advantage of the current invention that it provides an intuitive computer display interface allowing the user to automatically control the position of a cursor or mouse pointer on a computer-generated virtual page by directly coupling the user""s head movements to movements of a cursor across the virtual page, thus freeing the user""s hands for other tasks.
It is an additional advantage of the present invention that it provides hands-free instantaneous selection from between many concurrently active computer applications by changing one""s line-of-sight from one application window""s virtual location to another.
It is yet another advantage of the present invention that it provides and maintains a cursor at a user-selectable position within the user""s field-of-view, in order to support use of the virtual computer display by users with arbitrary, non-central preferred retinal loci.
It is still another advantage of the present invention that it alerts the user to events occurring outside of the user""s instantaneous field-of-view through the use of spatialized audio alerts perceived to originate from the direction of the event, thus causing the user to turn and look in the direction of the event.
It is yet a further advantage of the present invention that it provides effective operation at magnifications much greater than those possible using fixed monitors, by using a novel technique known as spatial compression.
It is still another advantage of the present invention that it provides improved scrolling of imagery across the user""s field-of-view, through application of smoothing, thresholding, prediction, and drift compensation algorithms to improve response to raw data representing the user""s instantaneous line of sight.
It is still a further advantage of the present invention that it provides a computer display for visually-impaired users that is convenient, lightweight, low-cost, minimally power hungry, and capable of portable operation without degraded performance.
It is another advantage of the present invention that it provides a means for visually-impaired users to view enlarged video imagery in real time over an expanded field-of-regard, thus reducing jitter compared to head-mounted closed-circuit television systems.

Portable game display and method for controlling same


A connecting plate for connecting I-beams together. The connecting plate contains at least two plates that each have a series of holes drilled in them. These series of holes are drilled offset from each other in each plate. The connecting plate can be in the form of a flat face, an L-shaped plate or a partially H-shaped plate. The offset holes on these plates allow the plates to be connected to a first I-beam first, and then connected to a second I-beam. This design allows a user to forgo coupling the first I-beam, the coupling plate and the second I-beam together all at the same time which improves the safety and efficiency of coupling I-beams together.

The following references are known in the art: U.S. Pat. Nos. 6,076,325; 6,073,405; 4,095,912; 4,124,123; 2,619,687; 1,786,145; 1,258,408; 1,214,738 of which all are incorporated by reference.
Work in the construction industry can be quite dangerous. The joining of I-beams together is an especially dangerous act because connecting two I-beams together may result in injury if these I-beams start to shift during the connection process. Therefore, it is important to get these two I-beams connected together quickly and safely. To achieve this goal, the I-beams must be connected together in a preliminary manner, to hold the I-beams together so that they can be subsequently connected together in a more permanent manner.
The present state of the art suffers from the following problem in that none of the references cited describe an I-beam connector that connects two different I-beams together using two sets of holes offset from each other so that these I-beams can remain preliminarily connected before they are fully connected together.
The present invention was designed to overcome the problems of the art by presenting an I-beam connector that connects two or more I-beams together in both a preliminary manner and then subsequently in a more permanent manner. Essentially, there is an I-beam connector that is made from at least one plate that can have two different series of holes offset from each other. These holes are offset from each other so that two different I-Beams can be connected to at least one connecting plate individually and sequentially.
The present invention can take the form of up to two different embodiments. In the first embodiment, the connector is an L-shaped plate having two sets of holes offset from each other so that two different I-beams can be connected together at a right angle. In the second embodiment, the connector is a partially H-shaped plate that is designed to couple to both sides of an I-beam.
Regardless of the type of embodiment or plate used, the plate is used to fasten first to a first I-beam and then to a second I-beam. The process occurs by creating a plurality of holes in a first I-beam by drilling punching, or any other method known in the art. Next, a second set of holes are drilled into the second I-beam. The connector is fastened in an offset manner so that a first connector can be coupled to the I-beam and next, a second connector can be coupled to the I-beam. Next, The connector is then fastened to the first I-beam. Once the connector is fastened to the I-beam, the second I-beam is fastened to the connector. Finally, a third I-beam can be connected to a connecting plate, wherein this third I-beam joins with the first and the second I-beam in an offset manner. In that way, a user can connect the connector first to the first I-beam without the second I-beam being involved. This results in a safer process for coupling two or more different I-beams together because a user has a much greater chance of injuring herself when coupling two or more different I-beams and a connector all at once.

Process and device for connecting I-beams


A training system and method for use of simulated night vision goggles (NVG) which provides the full dynamic range of NVG simulation including low intensity, medium intensity and high intensity irradiance images of night-time terrain. Each of three 12-bit video signals are allocated to a preselected portion or all of the total irradiance range representing scene elements corresponding to low, medium and high light intensity and a video camera scans and converts the resultant generated image to preserve its resolution and dynamic range. The image is viewable in the simulated goggles.

This invention relates to a training system and method for implementing the system, and more particularly, a system and method for training aircrew pilots in the use of night vision goggles.
The training of aircrew pilots in the use of night vision goggles (NVG) is typically conducted in a classroom setting through the use of courseware and instructional videos, supplemented by ground-based training simulators. Training simulators equipped with NVG apparatus allow pilots to train in more realistic environments under task-loaded conditions. The available technology and associated costs limited the fidelity and application of such ground-based NVG simulation.
There are two traditional technical approaches to NVG training in a simulator. The first is known as the stimulated approach, in which the pilot wears actual NVG flight hardware in the training simulator and the goggles are stimulated using a visual display system and digital image generator. The second approach is known as simulation, in which the pilot wears a head-mounted display (HMD) driven by an image generator and digital post processing system.
In the stimulated approach, infrared (IR) projectors (or sometimes just red CRTs and appropriate filters) are used to stimulate actual NVG. The projectors must have sufficient power and dynamic range to provide the full range of irradiance at the entrance pupil of the NVG thus emulating actual environment radiant power reflecting diffusely off natural terrain under all phases of the moon. Sufficient dynamic range is provided through a combination of video gray scale quantization and a separate projector dynamic gain control and optical filters to reproduce dark overcast night to full moon and clear night. For multi-screen display systems, this complex projector system must be replicated for each screen. This approach does not however, provide sufficient irradiance to provide the additional dynamic range (on the order of 120 DB) needed to reproduce effects produced by the direct viewing of bright lights, explosions or flares, so some of these effects need to be simulated in the image generator. Furthermore, for high fidelity NVG terrain simulation it is necessary that the image generator render the night scene using a physics based, radiometrically correct reflectance model based on a high fidelity lunar and atmospheric model.
The display is viewed directly by the NVG through the green notch filter of the NVG in the same manner as in the aircraft. This provides a stable image which is not displaced from the aircraft boresight by even slight head movements and does not appear to xe2x80x9cswimxe2x80x9d or xe2x80x9cjitterxe2x80x9d as it does when the image is produced on helmet, e.g., in a HMD system, by mixing this video with simulated NVG imagery. The image produced by NVG stimulation through the display projector is also significantly more stable than when simulated NVGs are used. This is because the image is produced off the helmet, as it is in the real world.
A further significant disadvantage of this approach is that the entire environment must be xe2x80x9clight tightxe2x80x9d to prevent spurious light from reaching the goggles.
In the simulated approach, just as in the stimulated approach, a high-fidelity physics-based, NVG terrain simulation image generator and database are used to render the night scene using a physics-based, radiometrically correct lunar and atmospheric reflectance model. The principal difference between the simulated and stimulated approaches is that in the simulated approach actual NVGs are not used and the sensor effects are simulated in a video post processor for display on helmet-mounted CRTs constructed to resemble NVGs. The video post processor computes the average intensity value of the scene in the instantaneous field of view. It then uses this data, along with the information on lunar and atmospheric conditions, to set gain and to inject the appropriate level of scintillation noise into the video signal provided to the simulated NVG display. The gain and noise level appropriate to the simulated nighttime scene are calibrated according to empirical data gathered by observation of actual NVG as used in the real world. Halos around intense light sources must be simulated in size and other qualitative effects in the image generator in the same manner as described for the simulated approach.
The simulated NVG cannot view the direct or head up display (HUD) directly, so a simulated HUD model must be used to generate HUD video that is mixed with simulated NVG video for display on the simulated NVG display. This HUD presentation is subject to xe2x80x9cswimxe2x80x9d, which may be distracting. Also, the use of helmet-mounted displays has never been widely accepted by the training community due to complex human factors issues.
Accordingly, this invention relates to a training system for teaching the use of night vision goggles including a means for generating high fidelity, infrared, terrain simulation images, and means in communication with the image generation means for providing sufficient irradiance to increase the dynamic range needed to reproduce effects to simulate direct viewing of bright lights such as produced by explosions and flares, and more particularly to increase the dynamic range needed to reproduce effects to simulate direct viewing of bright lights.
In another aspect of the present invention, a method for simulating night vision as seen through a pair of goggles comprises the steps of: a. providing a pair of simulated goggles; b. generating a high fidelity, infrared, terrain simulation image viewable in the goggles; c. simulating the entire range of natural night time terrain irradiance, and d. scan converting the resultant image generated to video for display through the simulated goggles.
This invention relates specifically to a training system and method in the use of night vision goggles with a proposed hybrid of the simulation and stimulation approaches, which eliminates the need for the complex post processing hardware/software required by the stimulation approach and the complex projection system required by the simulation approach. The present approach is also unique in that it provides the full dynamic range of NVG simulation. The stimulation of actual NVG is performed off-helmet and the resulting image in the NVG eyepiece is scan-converted to video for on-helmet display on simulated goggles or projected on a display screen using an area of interest display system.
Multiple IR CRTs with combining optics and appropriately weighted neutral density filters provide the stimulation. Each CRT is driven by successively higher order bytes of digital video so that up to 200 DB dynamic range of irradiance (10xc3x97order of magnitude) is provided to an NVG image intensifier tube. The NVG and associated stimulation apparatus are packaged in a xe2x80x9clight tightxe2x80x9d package with appropriate light baffles and optical coatings to limit light scatter so as to maintain contrast. This is possible because the higher intensity sources, which must be imaged onto the light intensifier, are typically point sources, which, although very intense, do not add excessive amounts of radiance to the light path. Halos, scintillation, noise and automatic gain control (AGC) effects are produced in the goggle image intensifier and are 100% faithful to the NVG physics because actual NVGs are used. Each of three 12-bit video signals are allocated to the appropriate portion of the total irradiance range according to the scene elements which they represent, as follows:
Low Intensity: Natural terrain irradiance resulting from starlight, moonlight and other natural night sky irradiators
Medium Intensity: Distant and/or low intensity radiators such as aircraft lights, stars, moon, distant cultural lights
High Intensity: Close and/or high intensity radiators such as beacons, flares, missile firing, explosions
The entire range of natural night-time terrain irradiance is assigned to one of the three video signals, the other two are used to represent the full range of natural and artificial radiators when directly viewed by NVG and for light reflected from intense artificial sources. The image generator allocates point radiators and extended area reflectors of especially powerful irradiators to the proper video signal by a dynamic assignment process based on a computation of radiated power, distance from the simulated eyepoint and atmospheric attenuation. The output of the NVG image intensifier is scan converted by a high resolution 12 bit video camera to preserve its resolution and dynamic range.


A circuit for generating a digital noise signal characterized by an evenly distributed frequency content for a particular frequency bandwidth of the digital noise signal includes a word signal generator for generating a random sequence of N-bit digital word signals with each cycle of a system clock signal provided to the word signal generator, where N is a non-zero integer. The noise generating circuit further includes a shaping circuit which transforms the random sequence into a shaped sequence of N-bit digital word signals, and a frequency synthesizer which is responsive to the shaped sequence and which generates the digital noise signal.

1. Field of the Invention
This invention relates to a noise generation method and system, and more particularly to a shaped digital noise generation method and system.
2. Description of the Prior Art
Conventionally, digital noise generation is implemented by sampling an analog noise source, such as a noise diode, i.e., sampling white noise. However, digital noise generated by sampling white noise generally results in several undesirable effects. For example, analog noise sources display inconsistent unit-to-unit operation and relatively high failure rates, requiring frequent readjustments. In addition, thermal sensitivity inherent in analog noise sources may affect the consistency of the performance of the noise source rendering the quality of digital noise generated therefrom inconsistent over time.
Conventional digital noise generation also includes a method whereby multiple parallel taps off a single linear feedback shift register are used to develop a sequence of random digital word signals. The sequence of random digital word signals is provided to a frequency modulating synthesizer which translates the sequence to a digital noise signal. The frequency of the digital noise signal vary with each new word signal of the sequence. This approach, however, like the technique that consists of directly sampling white noise, has drawbacks. For example, varying the frequency of a digital noise signal in accordance with a generated sequence of digital word signals may produce an even frequency distribution with an uneven frequency rate distribution within the noise signal generated thereby. More specifically, the frequency rate distribution within the digital noise signal will reflect a gaussian rather than flat character for a particular frequency bandwidth mapped by the generated sequence. Thus, a desirable flat crossing rate distribution will not appear in the noise distribution and the power spectral density of the generated noise signal.

Shaped digital noise signal generator and method

AIL Systems, Inc., Subsidiary of Eaton Corp.


A process for producing an object which has optical layers comprising the steps of applying optical layers to a substrate of plastic material wherein the optical layers are applied by means of a chemical plasma-impulse vaporization process (PICVD).

The invention relates to an object, comprising a substrate of a plastic material, as well as a plurality of optical layers. Such objects can be optical components such as lenses, prisms, reflectors.
A reflector comprises an essentially funnel-like base body which is reflectingly coated on its inner surface. Reflectors of this type are components of lamps of every possible type, such as, for example, spotlights. They consist of the materials glass, metal or plastic. The metal and plastic reflectors used in the automobile sector are provided with a metallic reflecting surface, which also reflects heat radiation.
In the zone of such reflectors considerable amounts of heat occur, which lead locally to temperatures of up to 200xc2x0 C. If the reflectors are made of glass, then no problems arise with respect to the temperatures mentioned.
Cold-light coated reflectors of glass substrates are found today, inter alia, in the general illumination field or in the stage lighting field. The cold-light coating there reflects only the visible radiation and transmits the heat radiation.
By reason of today""s spotlight geometries in motor vehicles with metallically coated reflectors, the infrared radiation reflected in this way leads to locally high thermal loads on components that follow in the beam path, such as, for example, lenses, covering panes and others. By reason of this load today these components as a rule have to be used as glass substrates and/or be protected by special coatings against the heat radiation.
In the automobile industry it is increasingly a matter of the saving of weight, since a weight reduction contributes to the saving of fuel. For this reason attempts are made insofar as possible to use plastic as a substitute material for other materials, for example, for steel. In the case of the glass reflector, however, so far this was not possible. The reflecting surface, namely, would have to be provided with a cold-light mirror. So far this has failed because it was not possible to fix such a cold-light mirror lastingly on a plastic.
There are also known processes for the production of objects comprising plastic material substrates with layers located on them. Such a process is described in DE 195 23 444 A1. There a plastic is provided with a protective layerxe2x80x94by means of a plasma-supported CVD process (PICVD process)xe2x80x94by an electric high-frequency discharge at a reduced gas pressure. There it is a matter of achieving as high as possible a viscosity of this layer for the avoidance of embrittlement.
DE 197 03 538 A1 describes a process for modifying surfaces of PMMA substrates. Here the substrate surface is provided with a protective layer. Therewith it is supposedly possible to achieve an improved adhesion of function layers subsequently to be applied. The applying of the protective layer mentioned presents an additional process step and means, therefore, additional expenditure and costs.
Further processes for applying thin layers to plastic substrates are described in DE 34 13 019 A1, EP 0 422 323 A1, DE 04 116 A1 and others. There it is also a matter, inter alia, of the adhesion of the layer that is applied to the substrate and, namely, by means of the CVD or PICVD process. DE 100 10 766 shows and describes a process and a device for coating in particular curved substrates, for example, of eyeglasses.
The processes used hitherto have not been satisfactory. The necessary adhesive strength was not achieved. On the contrary, with objects produced in such manner there is the danger of the detaching of the intermediate layer mentioned, and therewith of the entire layer pack. This can lead to the result that the object will become prematurely unusable.
Underlying the invention is the problem of giving a process with which a substrate of plastic can be lastingly and dependably provided with optical layers. In particular there is to be achieved herewith a permanent bonding of the layers to the substrate as well as of the layers among one another.
This problem is solved by the features of the independent claims.
The inventors have perceived that a lasting and dependable fixing of the alternating layers to the plastic as well as of the alternating layers among one another is attainable if the alternating layers are applied to the plastic substrate with a quite definitive process, namely by means of the so-called PICVC process (chemical plasma impulse vaporization).
In the hitherto used PICVC processes for applying layers to a substrate the interface of the substrate is disturbed or destroyed in its structure by the associated energy burden. This results in a reduction of the adhesiveness between substrate and adjoining layer. The inventors have perceived, accordingly, that the energy load which is associated with the plasma discharge must be minimized in order to enhance the adhesion. There it is a matters both of the quantity of the applied energy as well as also of the manner of its application. The admissible limit value of the load for achieving an adhesion sufficient in practice can be determined by experiment.
By the invention there can be utilized the advantages known per se of plastic material, in particular the low weight and the easy deformability, which plays a special role in automobile manufacture, as well as the avoidance of the hazards that are associated with the splintering of glass. Furthermore, if need be, it is possible to forgo the use of grounding layers such as grounding lacquers.
As plastic material there come into consideration high-performance plastics which are stable if possible up to a temperature of 100 degrees Celsius or above. Here again the PICVC process works out favorably, since the substrate temperature is kept relatively low. The layers generated are themselves hard and lasting.
As especially good as plastic materials, there have proved the following substances:
Cycloolefin polymers (COP)
Cycloolefin copolymers (COC)
Polymethyl methacrylate (PMMA), or derivatives thereof.
Several properties of the COP and COC plastics make components of COP-COC plastics with optical interference layer systems especially well suited for their use as optical components with or without treatment or coating:
(i) High transparency with visible and near (nahmen) infrared spectral range, low double refraction
low light losses and low heating-up by heat absorption
(ii) High thermal form stability
(iii) Components made of COP/COC can be produced with a precision to that of glass
(iv) Barrier effect especially against water vapor
advantageous for good adhesion of layer systems
By reason of the properties mentioned COP and COC plastics can in many cases replace glass substrates and they therewith open up new possibilities in the design and layout of optical systems. In combination with specially adapted interference layer systems, high-quality optical components are producible.
With the PICVD process one has in hand a coating technology which, besides for the coating of glass and the like, is also excellently suited to the coating of plastic. An example of application for this is a plastic reflector with cold-light reflection, such as is of interest above all for the automobile industry. Cold-light coated reflectors of glass substrates are found today inter alia in the general illumination sector or in the stage-lighting sector. The cold-light coating there reflects only the visible radiation and transmits the heat radiation.
By reason of today""s headlight geometries in motor vehicles with metal coated reflectors the infrared radiation in this manner leads to high thermal loads on components that follow in the beam path, such as, for example, lenses, covering panes and the like. Because of this load, today these components must be installed as a rule as glass substrates and/or be protected against heat radiation by special coatings.
In the automobile industry it is increasingly a matter of the saving of weight, since a weight reduction contributes to the saving of fuel. For this reason attempts are made insofar as possible to use plastic material as a substitute for other materials, for example, for steel. In the case of the glass reflectors, however, this was hitherto not possible. The reflecting surface, namely, would have to be provided with a cold-light mirror. So far this has failed because it was not possible to fix such a cold-light mirror lastingly onto a plastic material.
According to the invention, therefore, the base body of the reflector is made of plastic material, with all its advantages which consist above all in a low specific weight and a low deformability. Also, the problem of splintering protection is eliminated.
Further, according to the invention the reflecting surface is constructed as a cold-light mirror. It consists suitably of a plurality of layers with different refraction coefficients. This coating reflects the visible radiation and lets the infrared radiation be transmitted (cold-light mirror principle).
According to the invention it has proved that the alternating layers are fixable dependably and durably to the plastic material, and, namely, if they are applied with quite definite processes to the plastic substrate, namely, by means of the plasma-impulse process or by means of chemical vaporization or by means of phase-impulse chemical vaporization. In a preferred form of the phase-impulse chemical vaporization process, the total duration of the plasma action amounts to at least {fraction (1/1000)} of the total action-free time span and is at most equal to this time span. The impulse action of the plasma lasts between 0.1 and 10 ms and preferably between 0.5 and 5 ms at a coating rate of the plasma action per time unit and per surface unit  greater than 10 nanometers/min. and preferably greater than 100 nanometers/min.
Because of the temperature load only high-performance plastics come into considerations that are stable at least up to 100xc2x0 C., and better higher. In order to apply hard lasting cold-light layer systems, as a rule high thermal loads on the substrate are required, which a plastic reflector does not endure without damage. Here the PICVD process offers itself, which as a pulsed process brings about only a slight energy charge into the substrate and thus keeps the substrate temperature low. On the other hand, in the pulses high plastic energy densities are generated that produce strong and durable layers. The coating is, as mentioned, a multiple coating. The individual layers are optical functional layers such as, for example, an anti-reflex layer, but also multi-function layers with special mechanical properties such as for example a hydrophobe cover layer, the so-called cleaning layer, which can easily be cleaned mechanically. Also layers with special optical and other properties come into consideration. Between the functional layers and the substrate there is generally applied a so-called bonding agent layer, here quite generally called xe2x80x9cinterlayerxe2x80x9d. This has a decisive importance for the usefulness of the entire product. It is responsible, namely, for the adhesion of the entire coating pack to the substrate. The interlayer can be a single homogeneous layer. It can also be a multiplex layer. There the individual layers form a gradient proceeding from a layer that follows immediately upon the substrate and, as an organicum, is identical or similar to a layer that is close to the next-following functional layer and is identical or similar to this as an inorganicum.
Further, the invention is usable with every type of coating. The coating properties can be controlled by the raw materials used as well as by the operating parameters of the installation. The layer properties can vary within wide limits. The interlayer will in general be a so-called gradient layer, which is composed of several layers, and in which the layer near the substrate is essentially identical to the substrate, and the layer remote from the substrate is essentially identical to the functional layers.
The invention can also be used with application of the so-called remote-PICVD process. Here, as is well known, plasma space and coating space are separate from one another. From the plasma space excited species are led into the coating space.


A surgical tool for use in implanting a heart pacer. The tool includes a handle from whose one end an Allen wrench extends and in whose other end an O-ring plug having a stem is removably held by the stem. The wrench serves to screw an Allen-head set screw into the pacer to secure the terminal of the catheter which connects the pacer to the heart electrically. The plug seals the hole in which the set screw is inserted preventing electrical leakage by reason of penetration of body fluids to the terminal. The stem is removed from the plug and may serve to seal the suture hole in the pacer when the pacer is not sutured in place.

This invention relates to the art of surgical tools and has particular relationship to tools for use in the implanting of a heart pacer. A typical heart pacer is described in Purdy, et al, U.S. Pat. No. 3,866,616. Such a pacer is implanted in the body of the host, in the case of a human being, in the chest or abdomen. The heart pacer includes an electrical circuit for producing electrical pulses. This circuit is electrically connected to the heart through a catheter which has a terminal (or, in the case of a bi-polar circuit, a pair of terminals) that is inserted into a socket which is connected to the electrical circuit. The terminal is secured by a set screw screwed into the heart pacer laterally of the socket.
Surgeons who implant the pacers have in general followed the practice of screwing the set screw tightly into the pacer so that its tip engages, and becomes cold welded to, the terminal. This practice alone has not proven entirely satisfactory. It has been found that there is electrical leakage through body fluids which contact the terminal directly and also through the set screw. To suppress this electrical leakage some surgeons have adopted the practice of plugging the opening in which the set screw is inserted, and which provides access to the body fluids, with a silicone-rubber cement during the implantation. This has not proven satisfactory. A preferred practice is to plug the opening with a silicone-rubber plug from whose periphery O-rings extend. The set screw is screwed in and the plug is plugged in during the implantation and this invention concerns itself with a tool for carrying out this operation.
In accordance with prior art practice, the surgeon carried out this operation with the aid of a hemostat or like instrument or with his fingers. With this practice the plug was not properly seated to produce an effective seal in the opening. At times the plug, being very small, was lost in the operating room or could even be left in the patient.
It is an object of this invention to overcome the difficulties and disadvantages of the prior art and to provide a tool both for screwing in the set screw of a heart pacer and for effectively sealing the set screw and the terminal of the pacer against penetration of body fluids during implantation.


The invention relates to a spray-dried composition comprising an active ingredient dispersed in a carrier comprising a combination of a wall-forming carbohydrate material with from 1 to 30% by weight of agar agar relative to the dried weight of the composition. The composition of the invention provides advantageous behavior in an aqueous environment wherein the mobility of the active agent is restricted in the gelled carrier, thus preventing the release of the agent unless shear of heat are applied. Another feature of the invention is a process for the preparation the spray-dried composition.

The present invention relates to compositions in an encapsulated form and to a method for the preparation of such compositions.
An encapsulation is a process by which one or more active ingredients are coated with, or entrapped within, another material or system. In the flavor industry, the encapsulation of flavor ingredients serves to retain the aroma in a food product during storage, protects the flavor from undesirable interactions with the food, minimizes flavor/flavor interactions, guards against either light induced reactions or oxidation, and provides a controlled release of the flavor.
In this industry, the most common processes for producing encapsulated products are spray-drying and, to a lesser extent, extrusion and coacervation.
Spray-drying is a well-known useful technique to stabilize flavors by encapsulating them in a solid form, suited to many applications. The spray-drying technology makes it possible to provide the same effect as extrusion, while providing very small particles.
In spray-dried powders, an active ingredient such as a flavor or a fragrance, usually hydrophobic, is entrapped as liquid droplets in a solidified matrix of a dehydrated carrier, generally consisting of carbohydrates, such as starches, hydrolyzed starches (maltodextrin), chemically modified starches, emulsifying polymers (gum arabic) and in certain instances monomers and dimers of simple aldohexoses, or any combination thereof. Conventional spray-drying techniques are perfectly well documented in the prior art. See for example Spray-Drying Handbook, 4th ed., K. Masters, (1985) or other reference books on the subject-matter.
The method for the preparation of a spray-dried powder typically first comprises the dispersion of a carrier in water, and then the mixture of this dispersion with a flavor before homogenization to form an oil-in-water emulsion. The emulsion is then spray-dried to produce a powdered flavor.
Flavors are traditionally spray-dried in water-soluble carbohydrate matrices. As these matrices dissolve in water readily, the most common applications of the corresponding powdered flavors are in dry beverage formulations. However, some applications in the flavor industry as well as in other fields such as the perfumery or the pharmaceutical domains require spray-dried products having a different behavior in an aqueous environment. In particular, powders which would not dissolve as quickly in water and which would even require another mechanical trigger for the release of the active ingredient encapsulated in the matrix, could be very useful for many applications.
Means to improve the dispersion of typical spray-dried powders have already been described in the prior art. Agglomeration constitutes such a means and finds applications for instance in instant coffee. However, this process does not suit all applications.
Now, we have been able to establish that a particular ingredient can be added to the carrier constituting the matrix of a spray-dried product, and, in combination with a wall-forming carbohydrate material, surprisingly improve the behavior of the powder in an aqueous environment. This ingredient is agar agar.
Agar agar is a hydrocolloid, the physical properties of which are well known in the art. More particularly, it has a widespread use in foods as a stabilizer, thickener, humectant and surface finisher.
Some patent literature discloses the spray-drying of agar itself to provide it in a solid form. On the other hand, agar is often cited as part of the list of encompassing materials susceptible of constituting carriers in an encapsulation system. As an example, one can cite WO 98/33394 which discloses the mixture of a bulking agent with a hydrocolloid in the form of a solid powder which is used as a stabilizing agent in a wide variety of products. However, no document from the prior art has ever pointed out or even suggested the possibility of using agar in a spray-dried composition for a specific purpose, when used in defined amounts and in combination with a carbohydrate material.
Yet, we have now been able to establish that, in combination with the main carrier material, namely a carbohydrate, and when used in specific amounts, agar agar is an advantageous co-carrier material for a composition intended to be spray-dried. In an unexpected manner, this novel composition proved to be responsible for a complete change in the product""s behavior, in an aqueous environment, and as regards the release characteristics of the active ingredient there-encapsulated, compared with conventional spray-dried powders.
The invention relates to a novel spray-dried composition, comprising one or more active ingredients dispersed in a carrier which comprises at least a wall-forming carbohydrate material and from 1 to 30% by weight of agar agar, relative to the dried weight of the composition.
What is meant here by xe2x80x9cactive ingredientxe2x80x9d is a liquid ingredient, preferably hydrophobic, which is sought to be protected by way of solid encapsulation. It may include volatile perfuming or flavoring ingredients as well as other kinds of ingredients such as pharmaceutical actives for instance.
The composition of the invention presents many advantages. While a typical spray-dried product dissolves instantly in water, the composition according to the present invention behaves in a totally different manner in such a medium and makes it possible to provide a controlled release of the encapsulated active ingredient.
Other embodiments of the invention include a method for the preparation of such a spray-dried composition, and its use for the flavoring or perfuming of consumer products such as foods, beverages, or perfuming compositions.
Finally, the spray-dried powder of the invention can also be advantageously used as an intermediate product or starting product for a double-encapsulation method, i.e., as a solid product susceptible of being subjected to a further encapsulation such as an extrusion in a glassy matrix to provide a granular delivery system, or to a second spray-drying operation in a distinct or similar matrix.
Further features, aspects and advantages of the invention will become apparent from the detailed description hereafter.
The present invention thus concerns a composition in the form of a spray-dried powder, comprising one or more active ingredients dispersed in a carrier, wherein said carrier comprises at least one wall-forming carbohydrate material and from 1 to 30% of agar agar, relative to the dried weight of the composition. In another embodiment, the proportion of agar agar in the composition can be limited to 1 to 20%, or even to 1 to 15% by weight, relative to the dried weight of the composition.
The spray-dried product of the invention is very useful in particular in an aqueous environment, where it provides a release of the active ingredient quite distinct from typical systems known in the prior art. More particularly, the addition of a certain amount of agar agar in the carrier matrix, in combination with a wall-forming carbohydrate material, provides a structure which swells upon hydration almost instantly and forms a gel wherein the mobility of the active ingredient in the form of oil droplets is restricted. As a consequence, even when excess water is present, the gel containing the oil droplets remains intact. Therefore, if the hydrated powder particles are left undisturbed, i.e., are not subjected to constant shear at room temperature, they can retain their integrity for at least 2 weeks, after which the release of the oil from the hydrated particles, when deformed under pressure, is observable. Thus, while typical spray-dried products dissolve instantaneously in an aqueous environment, providing an instant release of the encapsulated active ingredient, the system of the invention provides a controlled release of the active substance. Under another kind of trigger such as the application of shear force or heat, the active substance will be released from the dry powder.
The carrier of the spray-dried composition comprises at least one wall-forming carbohydrate material and from 1 to 30% of agar agar which may be in a partially hydrated form. This combination is responsible for the technical effect described herein.
Suitable wall-forming carbohydrate materials are substrates such as polyvinyl acetate, polyvinyl alcohol, dextrins, natural or modified starch, pectins, xanthans, alginates, or yet cellulose derivatives such as for example carboxymethyl cellulose, methyl cellulose or hydroxyethylcellulose. In one particular embodiment of the invention, the carbohydrate material is selected from the group consisting of a maltodextrin, or a corn syrup, a chemically modified starch, a hydrogenated starch hydrolysate, a succinylated or hydrolyzed starch.
The composition of the invention typically comprises from 70 to 99% by weight, relative to the dried weight of the composition, of wall-forming carbohydrate material. Preferably, it contains from 40 to 80% of carbohydrate material.
In a preferred embodiment, the matrix composition further comprises a plasticizer such as a sugar or sugar derivative, such as sucrose, glucose, lactose, levulose, fructose, maltose, ribose, dextrose, isomalt, sorbitol, mannitol, xylitol, lactitol, maltitol, pentatol, arabinose, pentose, xylose, galactose. Typically, the compositions of the invention may comprise from 0.1 to 50% by weight, relative to the weight of the dried product, of plasticizer.
An agar agar matrix, further comprising maltodextrin in admixture with one of the sugars mentioned above, in particular sucrose, is particularly appreciated.
In addition to carbohydrates and plasticizers, the composition of the invention may comprise an emulsifier intended to promote a homogeneous mix of the oil in the carbohydrate based mixture before spray-drying. The nature and proper amount of the emulsifier can be critically assessed by the process operator without undue experimentation. Typically, proportions form 1 to 30% by weight, relative to the dried weight of the composition, can be used.
Many suitable emulsifiers are known in the trade. Typical examples include soya lecithin, CAPSUL(copyright) (modified maize starch from National Starch), citric acid esters of fatty acids and emulsifying polymers such as gum arabic, but other suitable emulsifiers are cited in reference texts such as Food Emulsifiers and their Applications, 1997, edited by G. L. Hasenhuettl and R. W. Hartel, USA.
Finally, the composition of the invention, which is initially in the form of an aqueous emulsion, contains, before being spray-dried, from 50 to 90% of water, preferably from 60 to 85% by weight of water, relative to the total weight of the emulsion.
The active ingredient dispersed in the carrier of the spray-dried composition of the invention will preferably be a hydrophobic flavor or fragrance ingredient or composition of current use. However, the polarity or aqueous solubility of the active ingredient may be chosen as a function of the desired retardation of the release for a given application. In fact, more hydrophilic components will be released faster, as they are able to partition in the outer aqueous phase.
The terms xe2x80x9cflavor and fragrance ingredient or compositionxe2x80x9d as used herein are deemed to define a variety of flavor and fragrance materials of both natural and synthetic origin. They include single compounds and mixtures. The composition of the invention can encapsulate volatile or labile components in liquid form, preferably hydrophobic. Specific examples of such components may be found in the current literature, e.g., in Fenaroli""s Handbook of Flavor Ingredients, 1975, CRC Press; Synthetic Food Adjuncts, 1947 by M. B. Jacobs, edited by Van Nostrand; or Perfume and Flavor Chemicals by S. Arctander 1969, Montclair, N.J. (USA). These substances are well known to the person skilled in the art of perfuming, flavoring, and/or aromatizing consumer products, i.e., of imparting an odor and/or a flavor or taste to a consumer product traditionally perfumed or flavored, or of modifying the odor and/or taste of said consumer product.
Natural extracts can also be encapsulated into the system of the invention; these include e.g., citrus extracts such as lemon, orange, lime, grapefruit or mandarin oils, or coffee, tea, mint, cocoa, vanilla or essential oils of herbs and spices, among others.
The proportions of active ingredient in the composition are typically between 0.1 to 60% by weight, relative to the dried weight of the composition. In a particular embodiment, the proportion of the active ingredient is comprised between 20 and 50%.
The method for the preparation of a spray-dried powder comprises the steps of emulsifying the active ingredient with an aqueous solution of the matrix carrier comprising at least one wall-forming carbohydrate material and from 1 to 30%, preferably from 1 to 20% or more preferably from 1 to 15% of agar agar; homogenizing the emulsion and spray drying the latter to form a particulate product.
One particular advantage of the process according to the invention lies in the fact that the compositions comprising a combination of agar agar with a carbohydrate, as described herein, demonstrate a retention of the active ingredient (e.g., oil) which is advantageously not affected by a variation in the solid content of the starting aqueous emulsion. More particularly, in classical spray-drying processes, a high dilution rate, useful to provide monodispersity of the powder, must be balanced with the fact that the higher is the dilution rate, the lower will be the flavor retention. It is furthermore established that 10% lower solid content in the initial aqueous emulsion should result in noticeably decreasing the flavor retention after spray-drying. Now, it turned out in the present case that, as shown in the examples below, the flavor retention of the product of the invention is not affected by the dilution rate, or solid content in the aqueous emulsion introduced into the spray-drier. In other words, high dilution rates may be employed in order to get a good monodispersity of the powder without causing any drawbacks on flavor retention, a totally unexpected result for this kind of composition.
The spray-drying apparatus used in the process of the invention can be any of the various commercially available apparatus. Examples of spray-drying apparatuses are the Anhydro Dryers (origin: Anhydro Corp. of Attleboro Falls, Mass.), the Niro Dryer (manufactured by Niro Atomizer Ltd., Copenhagen, Denmark), or a Leaflash apparatus (origin: CCM Sulzer). A spray-drier with a pressure nozzle is preferred.
The process will be described below in a more detailed manner in Example 1. However, the parameters are not critical and the characteristics of a spray-drying process are well known in the art and can be easily adjusted by the skilled artisan.
The particulates of the invention typically have a size of between 50 and 70 xcexcm and a bulk density of between 0.4 and 0.6 g/cm3. However, a skilled person in the art knows well that the granulometry and the bulk density of the resulting dry powders can be adjusted by selecting the nozzle pressure until the powder having the desired flowability is obtained, so that other values are possible if desired.
The spray-dried powders prepared according to a process of the invention can be utilized as such in applications, for instance for the perfuming or flavoring of compositions wherein a release is induced by shear or heat. However, they also can be advantageously used as starting materials to be subjected to further processing, before being used as delivery systems in a variety of applications.
In particular, in one embodiment of the invention, the spray-dried particles obtained by the method described herein are further encapsulated in an extruded glassy matrix which may be formed from one or more carbohydrate materials or which may just comprise a plasticizer and an emulsifying agent, in order to produce a glassy matrix with an improved thermal stability. U.S. Pat. No. 5,087,461, the content of which is hereby expressly incorporated herein by reference, describes and exemplifies an encapsulation method of a spray-dried composition by way of extrusion. This process leads to narrow rods having a diameter in the range of 0.3 to 3 mm.
Apart from the extrusion, other kinds of encapsulation processing, following the spray-drying, are possible. The powder obtained can for instance be submitted to a second spray-drying, thus providing a two-stage spray-dried product. This technique in particular, as well as multi-stage spray-drying in general, are described by W. J. Coumans, P. J. A. M. Kerkhof and S. Bruin in Drying Technology, Vol. 12 (1 and 2), (1994), the teaching of which is also hereby included by reference.
These examples are not restrictive of the encapsulation techniques which can be used for further processing of the spray-dried powder obtained according to the present invention, notably with the aim of increasing the size of the particles, or improving a particular characteristic of the powder, in order to rend it suitable for specific applications.
The products of the invention, namely the spray-dried powder as such, as well as the spray-dried compositions further subjected to a second kind of encapsulation can be advantageously used for instance for the perfuming or flavoring of food compositions in particular.
Therefore, the delivery systems of the invention can be used in applications such as chewing gums or chewing sweets, savory food or baking in the field of flavors. Similarly the field of perfumery comprises many applications where this kind of encapsulation systems may be very useful. For instance all kinds of deodorants and antiperspirants constitute suitable applications for a perfuming delivery system with a controlled release of the perfuming ingredient and wherein the integrity of the latter is desirable until consumer use of for a certain period of time.
In those applications, the compositions of the invention provide a flavor or fragrance retention of up to 85% after the encapsulation process, at a fix level as high as 50%, and in an unexpected manner, the flavor retention being independent of the solid content of the aqueous emulsion introduced into the spray-drier. Moreover, the product hydrates very slowly in water and does not dissolve up to two weeks.

Spray-dried compositions and method for their preparation


A horizontally pivoted structurally rigid buoyant flood gate, in a housing for the gate arranged in front of an opening to a construction, is pivotally floated out of the housing by rising water entering a portal to the housing, and rotates buoyantly upward toward the opening, rising between two side walls longitudinal to the opening and separated from each other by little more than the side-to-side distance of the gate, allowing little water through any gap separating the gate from the side walls, which preferably is sealed by a compression seal, the hydrostatic pressure of water dammed behind the rising gate urging completed closure of the gate through at least the upper half of the closing arc, pressing the gate sealingly against the jambs.

This invention generally relates to method and apparatus for regulating the flow of water, more particularly, to water gates, and especially water gates in which the water gate turns about a pivot axis which is generally parallel to the horizon.
Major flooding too often happens in urban areas when runoff of surface water from sustained and heavy rains, or stream overflow, or cresting or penetration of water retention dikes, overwhelms water drainage and removal systems. At high risk in any such situation are buildings with subterranean areas including basements, subterranean tunnels and halls, parking garages and the like. Surface water invading through open entries of the buildings runs to lower levels. As lower levels fill, flooding can climb to higher subterranean floors and to adjacent buildings if buildings are connected by underground pedestrian or utility tunnels. If standby power generators and/or fuel powered water evacuation pumps are located below surface grade, such as in a basement, as all too often is the case, the power generators and water pumps can be disabled by water flooding into an area where they are located, removing often the last line of flood defense of the building.
Openings to buildings through which rising water can invade include entrances to covered receiving and loading docks, to underground parking areas and garages, to descending stairwells, and to vents, and potential entrances include grade-level and below grade windows or doors. Bottom-hinged xe2x80x9cflip-upxe2x80x9d flood gates, with inflatable gaskets, that are floor recessed when not in use, that have an exposed surface for traffic passage, and that are raised by hydraulic cylinders or winches, are commercially available. Other also not automatic building water barriers are shown in U.S. Pat. No. 5,943,832 for flood or storm resistant barriers for doorways or window opening; U.S. Pat. No. 5,283,979 for locking/opening system for watertight hatch, U.S. Pat. No. 4,582,451 for floodgate panel and sealing means therefor; and U.S. Pat. No. 4,355,000 for lightweight, removable gate seal.
Storms that produce locally heavy flooding occur only sporadically, so available flood gates of the art as described above remain in a retracted position for long periods of time. Because these flood gates are not automatic, on-site or on-call personnel are required to put them into barrier position when a high water inundation event is anticipated. When the event is a cresting river or the like, there is some advance notice. Unfortunately, nature sometimes comes calling torrentially, unexpectedly and inconveniently, when personnel are not on site, such as the middle of the night, and even if on-call, the personnel may be prevented by flooding of roadways from getting to the site in time to erect the flood gates before the structure meant to be protected is already inundated.
There have been efforts to automate erection of flood gates. One such example is U.S. Pat. No. 5,460,462, in which a vertically disposed flotation barrier elevates on guide tracks between channel posts when water rises within a vertical subterranean housing containing the flotation barrier. There are disadvantages, however, to such a vertical barrier. Hydrostatic forces generated by rising surface water press the barrier against its tracks, increasing friction and causing the barrier to resist the buoyancy forces working to raise the barrier vertically. Installation of the vertically disposed buoyant barrier requires evacuation of ground for the supporting structure to depth greater than the full height the barrier. Particularly in existing constructions such as parking garages and tunnels, the building structure itself or buried ancillary structure prevents excavations to a depth needed for placement of a vertical barrier. In addition, when a flood recedes, mud and flood debris from the water remain, and removal of debris from a tall, thin vertical slot in the ground, occluded with the flotation barrier, presents maintenance difficulties.
U.S. Pat. No. 4,377,352, issued Mar. 22, 1983 to Goodstein, describes a self-actuating water containment barrier for guarding open fields along flooding streams or rising lakes. The barrier comprises a plurality of stanchions which are mounted for pivotal movement from a normal dormant horizontal position, to an active vertical position. The stanchions are interconnected with water barrier-forming sheeting to form a barrier which can conform to a particular land mass or shoreline. Float members are mounted on the bottom of the outer ends of the stanchions. At low water levels, the float members rest on a shallow body of water or on the ground in a near horizontal position. As the level of the water rises, the float members cause the adjacent stanchions to pivot into a vertical position, thereby raising the sheeting between them to form a water barrier. This water barrier float system is unsuitable for guarding openings to constructions where cars or human beings must normally pass over the apparatus involved during the long times when the apparatus is retracted at rest.
This invention provides a flood guard method and apparatus for automatically refusing admission of rising surface water into a structural opening of a construction. By xe2x80x9cconstructionxe2x80x9d is meant any structure, building, erection, edifice or the like, and includes interior and exterior partitions and walls, in which openings such as doors or windows may occur, for passage from outside the construction to its interior, or within the construction from one room to another, or from one side of a partition to the other side, and this includes elongated passages such as tunnels and halls. The construction and the opening in the construction may be at ground level or below ground level, such as an underground parking garage, a basement, a subterranean tunnel or other subterranean space, so long as access to the construction or from one part of the construction to another is by an opening through which water can flow under the force of gravity. The essential factor is that the invention guards against flooding from surface water through an opening to the construction.
In general, the invention involves (i) pivoting a buoyant and structurally rigid flood gate from adjacent grade about an axis at the base of the gate arranged adjacent the bottom of a construction opening generally parallel to grade, such that, on rise of surface water sufficient to float the gate, the gate is buoyed and by force of rising water is rotated about the pivot axis in the direction of the opening, and (ii) as the gate buoyantly rotates upwardly, preventing the rising water from flowing around the sides of the gate sufficiently that enough hydraulic pressure is impressed on the gate by the rising water to push the gate into closing contact with stops or jambs adjacent the sides of the opening, thereby closing the opening and barring admission of flood water into the construction. The combination of an initial buoyant rotation of the gate upwardly about a horizontal axis followed by hydraulic force from water accumulated against the back of the up-rotated gate completes closure of the opening (with closure maintained by impress of hydraulic pressure). With a buoyant flood gate reposed at grade, the buoyant action of the gate in response to rising surface water is a rotational closing force for less than half the closing movement, when hydraulic pressure forces from water accumulating on the water side of the gate take over and complete the closing movement. Gate buoyancy, dependant on a variety of factors, including amount and kind of buoyant material, weight, and height verses width of the gate, affects the relative degree to which buoyancy closing forces surrender primacy to hydrostatic closing forces in a particular design.
Thus this invention provides a method for automatically refusing admission of rising surface water into a structural opening of a construction, the opening having opening-limiting margins, including a bottom, sides and usually a top. The method comprises (a) housing a buoyant gate of dimension occlusive to at least a lower portion of the opening adjacently in front of the opening, substantially parallel to grade, pivotingly arranged about a pivot axis parallel to the bottom of the opening and in a recess into which surface water can flow, (b) providing a portal for admitting surface water into the recess to cause the gate to pivotingly buoy upwardly from the recess in a rotation closing towards the opening, and (c) preventing rising surface water from flowing around sides of the upwardly buoyed gate, whereby rising surface water accumulates behind the gate and hydraulic pressure of the rising surface water exerts a continuing closing force rotating the gate toward, thence occlusively across, at least a lower portion of the opening.
Apparatus is provided in accordance with the invention to perform the function of the invention. A self actuating flood guard for refusing admission of rising surface water into a structural opening of a construction, the opening having opening-limiting margins, including a bottom, sides and usually a top, comprises (1) a buoyant gate having a base, sides, a front, a back and dimensions occlusive of at least a lower portion of the opening, the base being arranged for location adjacent the bottom of the opening, (2) pivotation members hinging the gate at the base about a pivot axis parallel to the bottom of the opening and allowing the gate to rest substantially parallel and adjacent grade proximately in front of the opening for pivotation upwardly toward and transversely to the opening, (3) a pair of upright walls reaching from grade and extending alongside the sides of the gate at rest, the walls having facing surfaces spaced apart sufficiently to allow the gate to pivot upwardly between them toward the opening with the sides of the gate close enough to the facing wall surfaces to permit hydrostatic pressure of surface water rising from the grade to develop against the back of the gate effective to impart a closing force on the gate after the gate buoyantly has pivoted from rest upwardly about the axis, and (4) jambs adjacent the sides of the opening for confronting and stopping rotation of the gate about the axis when the gate is rotated a predetermined extent under the closing force of the rising water hydrostatic pressure, thereby putting the gate in a closed position refusing admission of rising water into at least a lower portion of the opening. The predetermined extent suitably but not necessarily is an extent that places the jambs substantially upright but not in excess of 90 degrees relative to the grade.
The flood guard advantageously comprises a housing for the gate and pivotation members, the housing including a floor and sides for containing the gate above the floor such that with the gate resident in the housing the front of the gate substantially closes the gate housing. In many applications the gate is weight bearing, and when resident in the housing, it provides a passageway for traffic into the construction through the opening.
The gate housing further comprises a surface water portal into the housing giving access to the floor of the housing when the gate is resident in the housing, the housing and gate being configured to permit surface water entering through the portal to rise beneath the gate and pivotingly buoy the gate upwardly from the housing for rotation about the axis toward the opening. Optionally the portal is located in the housing at least adjacent the location in the housing remote from where the base of the gate is pivoted.
A drain is provided in the gate housing to remove waters flowing into the housing. Typically the removed water is emptied to a storm water collector tributary such as storm sewer, ditch, canal or other water collecting and removal system, including return to streets to discharge from the street to ditches or to storm sewers accessed by inlets along the sides of the streets. The purpose of the drain is to prevent the gate from floating up and out of its housing on the occasion of a heavy downpour which has not become a flooding situation. So long as the storm sewer or other water collector system is not full, water will not back up in the drain but will flow out and be removed by the water collector system. But in a condition where storm sewers are full and flowing at maximum rate, a limiting condition has been reached; street water no is longer accepted in the storm sewer, piles up, spreads and rises. This is the situation where the gate self-actuates, because the gate housing drain can no longer discharge its received water, and water entering the housing portal rises, elevating the gate. Thus the gate does not elevate during a mere heavy downpour but only when there is rising surface water in a flooding condition.
Seals affixed to the sides of the gate sealingly closing the gaps between the sides of the gate and the facing wall surfaces during rotation of the gate toward the opening of the construction. Suitably the seals are contact seals, preferably of a type that compress when brought into engagement with the walls during rotation toward the opening.
In one embodiment the jambs are affixed to the upright walls adjacent the opening and reach upwardly from adjacent grade. The jambs may reach an elevation proximate the height of the upright walls adjacent the opening, and may and preferably do include a resilient sealing surface arranged to cooperate with facing surfaces of the front of the gate in the closed position to seal against admission of water between the jamb and the gate.
The gate comprises buoyant material, for example, it may comprise a plurality of sealed tubes arranged side by side, or a honeycomb core structure sealingly arranged between two rigid panels. Alternatively the gate may have a bladder for a flotation material.
While the rotation of the gate about a pivot axis parallel to the bottom of the opening to be protected describes an arc, the rise of surface water is planar to horizontal, so more than a right angular shape of the upright walls between which the gate rotates upwardly is surplus structure, although structure may be provided above the hypotenuse to the right angle triangle for appearance or architecturally pleasing reasons. The walls are, of course, water impervious.
The jambs may be affixed to the construction on the sides of the opening. Alternatively the jambs may be freestanding from grade level or may project toward the opening from the upright walls, but the jambs are always spaced apart not more than the spacing of facing surfaces of the walls. Where the jambs are freestanding, the jambs are arranged with respect to the construction to act as a barrage to water between the jambs and the construction. Where the jambs are part of the walls, the walls are arranged relative to the construction to form a barrage to water between the walls and the construction. In an application of the invention, the upright walls extend from the construction and in cooperation with the jambs and the gate in the closed position provide a barrage to water between the walls and the construction.
The invention works either where the grade on which it is installed is horizontal or is angled relative to horizontal, either declined or inclined. Thus the construction may be a parking garage with underground parking accessed by a downwardly sloped ramp in which the flood guard may be installed.
The system of the invention is completely passive and automatic. There is no power or maintenance requirement and the gate normally rests out of the way so that once it is installed, most people passing or driving over it don""t even realize it is there. The method and apparatus of this invention have advantages over a vertical rising gate such as disclosed in U.S. Pat. No. 5,460,462, described above. For one thing, hydrostatic pressure of the rising water works to the advantage of the flood gate system of this invention, rather than against it. As mentioned, in the buoyant vertically rising barrier, any forces generated by dammed water to one side of the barrier serve to press the barrier against its tracks, increasing friction and making the barrier more resistant to floating upwards to full elevation. In the instant invention, the water pressure actually pushes the gate into fully elevated position. The gate will fully close when the water reaches between about one-third to about one-half, e.g., about 35-45%, of the overall height of a normally horizontally retracted gate.
Further, installation of the barrier is vastly simplified due to its horizontal packaging. The buoyant gate and its housing can be as little as only about four inches in height, whereas a buoyant vertically rising barrier must be the installed to a depth equal to the full height of the barrier plus some additions for structural support. Installation in roadways, and particularly in parking garages or tunnel systems, where other structures may lie closely beneath, is made possible by the present invention due to the minimized need to excavate material. Actually the design of this invention can be installed without any digging at all where necessary; it can be installed on top of the approach surface to the construction opening and would look like a flat speed bump lying on the surface of the pavement.
Also, maintenance of the flood gate of the instant invention is greatly eased due to its horizontal nature. In the case of a flood, mud, debris, and other detritus is carried in the water. When the flood recedes, much of this material will fall out of the water and remain behind. Cleaning the flood gate of the instant invention will require the washing of a broad, flat pan compared to cleaning a tall, thin slot in the ground.
These and other advantages of the instant invention will become more apparent to those in the art from the description of an embodiment which follows after an identification of the drawings used in connection with the description.