Viewing transparencies through a hand-held dark tunnel improves visibility of shadow detail. It is particularly useful viewing medical radiographs where dark portions are commonly juxtaposed to bright areas. The dark tunnel improves visibility of the dark transilluminated areas by promoting darkness adaptation.

Background — Description of Prior Art

The retrieval of quality information from dark portions of medical radiographs can be life saving. Retrieval of information of microscopic detail is difficult also, especially in dark areas. These two problems are encountered during x-ray film analysis. They represent important parts of proper patient diagnosis. Contrarily, they are nuisance problems that interrupt the flow of work and require extra steps. Such conflict results in medico legal risk for physicians interpreting medical radiographs, especially mammograms.

Various styles of magnifying lenses have long been used to enhance viewing for fine detail in medical radiographs and other transilluminated materials. A magnifier lens is a prior-art component of the invention device described herein.

Dark portions of transparencies will appear black under normal lighting conditions, but often contain image forms which simply cannot be seen without special viewing conditions.

This paragraph reviews four approaches which have been used to deal with areas on film too dark to see under normal viewing conditions. 1. An extra film is taken with exposure altered to lighten the shadow areas; 2. A lower contrast him is produced, by using a different kind of film or by altering exposure and /or processing techniques. This enables a greater range of image contrast — light and dark areas — to be squeezed into the visible gray scale. With greater contrast scale, contrast resolution suffers, reducing the distinction of interfaces between nearby structures of similar shades of gray; 3. the intensity of light transmitted through

the dark areas of the film is increased. A "bright light" is the traditional and most commonly used device for examining dark areas on the films, but it requires time consuming manipulation of film and light. Intense heat associated with the bright light has damaged many a film; 4. Electronic image enhancements exist, using either night-viewing photo multiplier devices or by digitizing the images and making them amenable to manipulation of brightness, contrast, magnification and central gray level. Expensive, cumbersome and impractical for now, soon digitization will become the most common solution to the problems described.

A fifth solution to the problem, darkness adaptation, is presented as the basis of the invention herein.

By providing an environment where visual darkness adaptation is provoked, biochemically in the retina and by reflex dilation in the pupil, exceedingly weak light intensities can be detected by the human eye to distinguish form and detail. We have all experienced this phenomenon each time we step from a brightly lit room into what at first seems total darkness of night. We must wait a minute to see. Soon we dark adapt and can usually find enough light to see.

Another common experience reflects the opposite extreme. Bright headlights from on-coming traffic blind-us to the road and to roadside objects we could see easily before excess light was directed our way.

Physiologic darkness and brightness adaptation holds great influence over the accuracy of day to day medical image interpretation. X-ray illuminators blind radiologists in the same fashion as on-coming headlights. Dark areas in the film contain image information that is not visible under standard viewing conditions. Any easily employed viewing aid that enhances viewing conditions to promote darkness adaptation will be of great use to patients and radiologists alike.

Manufactured instruments have been produced over the years that take advantage of darkness adaptation and magnification for viewing transparencies. A few are binocular. One popular model of such an instrument exists for x-ray viewing, the Panascope Viewer (And over, CT). There exist at least two others with similar design (Tabar Viewer, GE Viewer).

The Panascope Viewer provides both magnification and darkness adaptation. It has a rectangular cross section. It is constructed from rigid durable plastic through-out. It is molded proximally only generally to conform to the face and nose to cover both eyes. Though quite helpful, the Panascope and the other similar viewers suffer from several deficiencies.

It is rigid. When in use, sudden contact against the x-ray illuminator or objects or people outside the field of view are common and can be painful to the face and nose.

Its rigid proximal end does not fit snugly against the face. Considerable light leaks in between the face and the proximal end of the Panascope. Such ambient light at least partially defeats darkness adaptation.

Also rigid, its distal opening cannot be made smaller or shaped to fit the dark portions on the transilluminated images. Thus it is usually impossible to exclude

any bright areas which also lie within the Panascope field of view near the dark area of interest. The forced inclusion of these bright areas blinds the eye and prevents optimal darkness adaptation.

Its rigid, one piece construction makes it difficult to reach inside to the deeply and permanently placed lens board to clean the magnifying lens or change it to a different magnification strength or lens type.

Its hard plastic is resistant to paint or multicolor dye decoration. It clatters when it falls. Though a very tough plastic, it could break on impact on a hard floor or produce damage to impact areas.

(At about $250, the Panascope is also very expensive.) Objects and Advantages

The invention of record replaces the rigid plastic with a soft, elastic flexible material for the viewing tunnel. Several objects and advantages of the present invention are;

(a) A new use of inexpensive a pliable welder's goggle to provide a soft, light- tight fit for effective light exclusion of ambient light where the proximal end of the viewing tunnel contacts the face. At the distal surface, the existing goggle has a slidable mount intended to hold dark safety glass and permit changing and cleaning of this glass. The slidable mount is suitable for easily attaching and detaching a simple custom manufactured opaque rigid oval lens board on which a magnification lens is mounted. Suitable binocular and monocular magnification lenses currently exist.

(b) Soft, elastic neoprene rubber-cloth laminate (wet suit material) is fabricated into an open ended opaque viewing cylinder. The neoprene laminate viewing cylinder uses its elastic properties to be stretch mounted over the perimeter of the oval lens board providing a continuous dark viewing tunnel formed by the goggle proximally and the neoprene cylinder distally, joined by the intermediate oval lens board;

Above (a) and (b) describe a four part design whereby:

(c) the opaque elastic neoprene laminate viewing cylinder can be attached and detached easily over the lens board perimeter. The alignment and length of said neoprene laminate viewing cylinder can be slidably adjusted over the lens board perimeter to match various magnification focal lengths and other desirable viewing conditions. Its distal opening can be folded into a cuff, to further expand its versatility;

(d) the distal end of said neoprene laminate viewing cylinder can be manually distorted from its baseline oval shape to conform to the shape of the dark area on the transparency, excluding nearby bright areas which detract from human darkness adaptation The magnitude of the viewing advantages provided by the distal aperture shaping means is difficult to perceive until personally experienced;

(e) said neoprene laminate viewing cylinder is supplied in many patterns and colors and can be easily dyed or painted with multi color designs,

(f) light in weight and imbued with a soft, non-slippery surface, said neoprene laminate viewing cylinder, lens board and welder's face goggle fall quietly and harmlessly onto hard surfaces. It is easy to pick up and easy to hold up. It can be hand held or mounted with a headband;

(g) removable neoprene laminate viewing cylinder and slidably removable lens board provide for ease in dismantling for lens cleaning or lens changing or for substitution of a special purpose high power lens described below;

(h) specialty high power lens combine with the light shielding properties of the welder's goggle to permit darkness adapted viewing of slides, microfilm and microfiche while they lie against a simple light box, bypassing the need for large microfilm projection viewers;

(i) one or several different lenses or special viewing devices, each mounted on a separate lens board, can be quickly changed using the slidable attachment indigenous to the welder's goggle as currently manufactured.

(j) advantages (a) through (f) and (i) and parts of (g) are maintained in a newer current preferred embodiment, wherein the welder's goggle have been deleted from the design. A lens cup slides in and out of a one-piece neoprene laminate viewing cylinder for easy lens change or cleaning, since the lens cup is held in place only by the elastic pressure inherent in a mildly stretched neoprene laminate cylinder.

(k) Advantages provided by the removable distal viewing cylinder of the parent device, such advantages expressed in parts of (g) and (h) above, are lost in the current preferred embodiment, but could be regained by providing two overlapping tunnels in place of the one-piece model.

Further objects and advantages will become apparent from a consideration of the ensuing description and drawings.

Drawings Figures

The current preferred embodiment is depicted in page two of drawings. The current preferred embodiment is a One-piece Neoprene Laminate Viewing Tunnel 14, cut to a face-fitting goggle shape at its proximal end. Said One-piece Neoprene Laminate Viewing Tunnel 14 is elastically stretched mildly over a central box-shaped lens board or lens-cup 16 onto which the binocular lens is mounted, where lens-cup 16 has sides that provide stability within the elastic tunnel. The distal end is oval and inherently elastic and flexible.

(The next five paragraphs contain important parent specification information that match with their drawing, but can be regarded briefly, since they are a complex embodiment that has since been simplified.)

Four figures are found on page one of drawings. They depict a design for a viewing tunnel used to examine dark forms and detail in transilluminated materials. The design is based a new use for existing manufactured welder's goggle and magnifier lenses and neoprene-cloth laminate (wet suit) material. These three components are connected together by a fourth component, an unbreakable opaque lens board. Together these components provide a darkened viewing tunnel which fits the face "light tight" on one end and has malleable and

conformable opening on the opposite end, the field-of-view end. The field-of- view end is positioned in contact with or very near to the surface of the transilluminated film or material.

Figure 1 shows the appearance of the assembled device as a perspective from the field-of-view end of the device.

Figure 2 shows a direct "en face" view into the face goggle end of the device. The obvious large oval structure is the lens board. The thin outline around the lens board is the neoprene rubber cylinder, stretch fitted over the perimeter of the lens board. Centrally one sees the magnifier lens in the opening of the welder's goggle.

Figure 3 shows a Top View of the disassembled device. To manufacture, the goggle window frame, the lens board and the magnifier lens are be fastened against one another (Fig 4). The distal goggle window is slidably attached to the goggle window frame-lens board. Finally, the neoprene rubber cylinder is stretched and drawn over the perimeter of the oval lens board.

Figure 4 shows a more detailed view of the Connector Parts, the welder's goggle window frame, the oval lens board and the magnifier lens.

Fig 5-10 begin on page 2 of 2. They depict a more current embodiment of the device, a simplification.

Fig 5 is a perspective of the new assembled device. It is quite comparable to Fig 1 on page 1. Fig 6 shows the same assembled device from a direct top view. These two figures depict One-piece Neoprene laminate Viewing Cylinder 14 as it stretches mildly over lens cup 16. It shows much more detail, using hidden lines to reveal the nose cut at the "goggle" end, the inner lens 2 and lens cup 16 and eye-glass accommodating wire restrainers 18. Restrainers 18 fit into holes in buttresses in the wall of lens cup 16 and can be bent by the user to accommodate for different size spectacles.

Fig 7, 8 and 9 show detail of lens cup 16 in various views. Fig 10 shows lens cup 16 in perspective similar to Fig 5.

Reference Numerals in the Drawings

1 Welder's Goggle 2 Binocular Magnifier Lens la Goggle Ventilators 10 Lens Board lb Goggle Window Carrier, 12 Neoprene Laminate with slidable connector Viewing Cylinder lc Goggle Window Frame, 14 One Piece Neoprene with mated connector. Laminate Viewing Cylinder

16 Lens Cup 18 Spectacle Accommodating

Wire Restrainers

Description — Figs 1-4

Four figures are found on page one of drawings. They depict the device of the parent specification, a small, hand-holdable device for viewing transilluminated materials. Said device provides magnification and a light-tight tunnel to provoke darkness adaptation. When viewing weakly illuminated areas, said viewing tunnel device provokes physiologic darkness adaptation, even in environments where bright sources of light exist nearby. The device is novel in its a.) proximal provision of a soft, light-tight-fitting face goggle as a means to completely exclude ambient light, a design principle formerly incorporated into diving masks and welding goggles, but not formerly incorporated into transparency viewers or x-ray viewers; and b.) distal provision of a flexible viewing opening as a means for closely shaping the field-of-view to match the shape of dark areas of viewing interest while excluding bright blinding sources of adjacent trans-illuminating light. The device is not obvious, since none like it exist after 100 years of radiology, 30 years of mammography and 5 or more years of the Panascope X-ray Viewer (Andover, CT).

The current preferred embodiment is depicted in page two of drawings. The current preferred embodiment is a One-piece Neoprene Laminate Viewing Tunnel 14, cut to a face-fitting goggle shape at its proximal end but open and oval at its distal end. Said One-piece Neoprene Laminate Viewing Tunnel 14 is elastically stretched mildly over a central box-shaped lens board or lens-cup 16 onto which the binocular lens 2 is mounted. Lens-cup 16 has sides that provide stability within the elastic tunnel. The distal end of One-piece Neoprene Laminate Viewing Tunnel 14 is an open oval, inherently elastic and flexible.

(The next six paragraphs contain important parent specification information to match the parent drawing, but can be regarded briefly, since they delineate a complex embodiment that has since been simplified to the above paragraph.)

The original parent design is based a new use an for existing manufactured welder's goggle 1 and plastic magnifier lens 2 . Neoprene rubber-cloth laminate (wet-suit) material is used to form the opaque viewing cylinder 12 , with the black, non reflective material on the inside and color or pattern of choice on the outside. These three components are connected by a fourth component, an unbreakable opaque lens board 14.

These components provide a dark viewing tunnel with light tight walls. The tunnel fits the face "light tight" on its proximal welder's goggle end. It has a malleable and conformable opening on the field-of-view end, because this distal end is made from said neoprene laminate (wet-suit) material.

Welder's Goggle 1 is made of a soft pliable rubber-plastic which is soft and molded to conform light-tight when pressed gently against a human face. Welder's Goggle 1 comes with light-defeating goggle ventilators la which are unimportant and would be deleted except for the expense of a building a new manufacturing mold. Welder's Goggle 1 has an attached distal window assembly which is made to contain dark safety glass seated in Goggle Window Carrier lb and prevented from falling out by a Goggle Window Frame lc which slidably mates with Goggle Window Carrier lb. Goggle Window Carrier lb is

manufactured fastened "light tight" to the body of Welder Goggle 1. The dark safety glass is removed from Welder Goggle Window Carrier lb and it is left empty. Manufactured lenses exist which fit in Welder Goggle Window Carrier lb that are a little too close to the eyes to yield a good working distance. However, this is a ramification alternative design for a magnifier holder.

The Welder Goggle Window Frame lc is attached to oval lens board 10 and existing manufactured lens 2 from Donegan Optical Company, Inc. (Lenexa Kansas), (see Fig 3 and 4). Since they are cheap, several pre-assembled window frame-lens board-lens combinations can be kept available, each with a different purpose lens on its lens board. The window frame-lens board-lens combination assemblies can be slidably mounted and dismounted from Welder Goggle 1.

Neoprene Rubber Viewing Cylinder 12 is fabricated with an oval cross sectional circumference slightly less than the outer circumference of lens board 10. Using only the strong elastic properties inherent in Neoprene Rubber Viewing Cylinder 12, its proximal opening is stretch-fitted over the perimeter of lens board 10, holding it firmly, but allowing easy detachment. This simple elastic mount allows adjustment of the viewing length of Neoprene Rubber Viewing Cylinder 12 to suit the user's preference or to adjust to the new focal length dictated by a change of lens. The soft Neoprene Rubber Viewing Cylinder 12 can be folded distally or proximally into a cuff to increase the range of possible adjustments to its length. Finally, if desired, the end-user can cut Neoprene Rubber Viewing Cylinder 12 to a different desired length with a pair of scissors.

Operation:

The viewing tunnel device is picked up by the hand of the user and pressed gently to the face so the eyes can view down the tunnel and the nose can breathe outside the face goggle. Light can only enter through the distal opening of the viewing tunnel. The distal opening of said viewing tunnel is brought close to the troublesome portion (dark or detailed or both) of the transilluminated material (x- ray, mammogram, photo, fabric, etc.) in order to: a. exclude ambient or nearby transilluminated bright light, and b. to enter the focal zone of the magnification lens.

If the desired area to view is troublesome due to inherent darkness and there is an interfering bright area of blinding light adjacent to it, the user's other hand temporarily shapes the distal opening so that the viewing tunnel's field-of-view matches the shape of the dark area, excluding the adjacent bright areas, permitting optimum physiologic darkness adapted viewing.

Lenses can be changed , allowing binocular magnification up to 3.5x. Monocular lenses can be used with magnification up to lOx for viewing transilluminated slides, microfilms or microfiche unaided by the usual projection equipment.

The device can be used for magnification without darkness adaptation by detaching said Neoprene Laminate Viewing Cylinder 12.

The same form and functions, except for the adjustable tunnel length and the detachable Viewing Cylinder 12 functions, exist in the current preferred

embodiment. The current preferred embodiment is a one piece Neoprene Laminate Viewing Tunnel 14, cut to a face-fitting goggle shape at its proximal end, elastically stretched over a central box-shaped lens board or lens-cup 16 onto which the binocular lens is mounted, where lens-cup 16 has sides that provide stability within the elastic tunnel. (By dividing Neoprene Laminate Viewing Tunnel 14 of the current preferred embodiment into two separate overlapping tunnels , the two lost functions may be regained. )

Summary:

The viewing tunnel device described herein is useful in viewing x-rays and other transilluminated materials, providing magnification and effective darkness adaptation. It is novel because a.) a soft, light-tight, face-fitting goggle formerly incorporated into diving masks and into welding goggles is being incorporated as a new use into a transillumination viewer; and b.) a flexibility means is incorporated into the distal viewing tunnel opening. The opening can be shaped to include the weakly illuminated area of interest and to exclude blinding bright areas. The device is not obvious, since none like it exists after 100 years of radiology and more than 5 years use of the "Tabar Viewer", the General Electric Viewer, and the Panascope Viewer (And over, CT).

The current preferred embodiment of viewing tunnel device consists of a goggle- shaped aperture proximally, a lens board for mounting a binocular lens centrally and a soft neoprene cylinder which is inherently flexible and conformable as the distal viewing aperture. The soft neoprene opening can be distorted, conformed and-or partially closed off in order to include only the dark or detailed target areas in the field-of-view, effectively excluding brighter parts of the image which would defeat darkness adaptation.

Ramifications:

Ramifications for adjusting the viewing tunnel's field of view to match the shape of the dark area to be viewed include: 1. flexible or rigid attachments to cover portions of an otherwise rigid field of view, such attachments fashioned with various sizes and shapes of holes to restrict the field of view; 2. an iris diaphragm type mechanism to adjustably restrict the field of view; and 3. sliding masks at the distal opening to shape or cone-down the field-of-view.

New use claims might include: light-weight, safe, unbreakable, stretchable, or use of composite materials with hard components but flexible distal aperture.

A ramification anticipated substitutes any suitable soft flexible, elastic material for the welder's goggle and neoprene used herein. Said ramification is, in fact, described herein as the new current preferred embodiment.

Scope

While the improvements claimed herein are primarily developed to solve problems while reading medical transparencies , the advantages conferred by the described improved viewing tunnel will transfer to any transilluminated material or scintillated material that needs to be viewed. Such materials include, but are not limited to, photo transparencies of various sizes, fabrics, windows, and video or CRT screens.