DE2837119A1 - OPTICAL SYSTEM FOR OBSERVING A CHAMBER WITH THICK WALLS - Google Patents

Description

2837118

Legal file : l · 34-1 - tf- - Daniel Louis LEGRaND

Password: "Safe Monitoring" Saint-Torre (Allier),

France

Optical, system
for observing a chamber with thick walls

The Jiri connection belongs to the field of optics and concerns one Device or an optical system for observing a chamber with thick «find, in particular a vault, with practical total visibility.

Devices are known which are generally referred to as "Optical viewing hole" are known, and with which an observer located behind a door is practically the entirety can see all objects on the landing, provided that these objects are adequately lit. are. Such devices generally consist of a double optical line with either a pair of lenses with a thick rim or a meniscus and a lens with a thick rim. This double line forms an optical system that is strong scatters and according to different arrangements of diopters an apparent picture of the totality of the stairs existing objects. In general, this becomes apparent Image viewed with the help of a converging lens, which at the same time allows some enlargement of the image and adjustment allowed to the eye. Such a system cannot of course be of great length in order to avoid a very dark picture. The aforementioned system of the optical viewing hole cannot be used across walls that are thicker than more than ten or a few inches.

The security of some walls, such as those of reinforced rooms or vaults in a bank, makes it necessary to that an inconspicuous, practically complete monitoring on a regular basis Distances from the outside through the wall

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can. In order to make such observation possible, the use of television cameras has already been proposed which are arranged at any point on the wall and allow the camera field to be monitored on the screen. Such a system, while effective, is very expensive.

It has also been suggested that a wall be enclosed Space with the help of a medical endoscope or periscope to monitor. A disadvantage of one or the other of these devices is that their field of view is greatly reduced is (for example at a fixed angle of between 30 and 60) and that such systems must accordingly pivot about their own axis in order to cover the entirety of the field to be monitored paint over. This means that the observation is no longer inconspicuous. The inconspicuousness is further made necessary by a certain Exceeding the wall boundary into the interior of the film is impaired. Another disadvantage is the not inconsiderable cost of such a device.

The invention is based on the object of creating a device with which the entirety of the objects present can be observed from one point in a room with very thick walls and with such an observation quality that corresponds to that which an optical viewing hole would allow if the wall of the room to be monitored were of a correspondingly small thickness. This object is achieved by the device or the optical system proposed by the present invention.

According to the invention, an optical system is specified which is centered on an optical axis, which is used to observe objects in a room across a wall and which has the following elements cooperating on the axis of the system: a first, diverging, optical system , which gives an initial, apparent and in front of it an image of the totality of the at least objects lying in front of it, a second optical system with an input end and an output

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end of the gear whose length along the optical axis is essentially is equal to the thickness of the wall, this second system converging in its entirety and serving the purpose of initial image to provide an end image in the area of its exit end, and a third system serving for accommodation, the it allows the eye behind him to see the previous image under an apparent diameter that is essentially is equal to that under which the initial image is seen at the input end of said second system, so that viewing objects across the optical system is essentially equivalent to the observation in terms of image quality and in particular in terms of light intensity, which could be made from an initial image directly with the optical accommodation system, where $ e, however, corresponding to that of the Invention underlying task, an extension of the optical System takes place, which is at least equal to the JJicke der vi / and is.

In particular and preferably, the first, diverging, optical system consists of two lenses, namely a meniscus with a thick rim, the front surface of which has a large radius of curvature in relation to the radius of curvature of its rear surface, the curvature of the rear surface being essentially hemispherical , and further comprising a biconcave lens, which is attached to the rear surface of the meniscus or bonded, and having two substantially mutually symmetrical surfaces whose radius and diameter is substantially similar mutually the same and significantly greater than that. ^he rear face of the meniscus are. The second optical system preferably consists of five identical lenses, which are arranged one behind the other on the optical axis, with the same mutual spacing, which is slightly less than twice their focal length. It follows from this that the linear enlargement of the system is significantly greater than one and in the range of two. The third optical system, the so-called accommodation system _9, preferably consists of a plano-convex lens with a visor, these two elements being at a mutual distance from one another, the

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between a quarter and half the focal length of the said Lens is. Has second optical system that the Image transmission is preferably arranged at such a distance from the first system that the initial apparent Image lies in a zone between the front focal point of the objefct of the first lens or lens with the input surface of this second system and in the vicinity of this focal point lies. It follows that the final image given by the second system of the initial image will be in the vicinity of the output end formed from the fifth lens. -Furthermore, it is expedient to place the named third system at a distance in this way to the second system is adjustable, is approximately equal to half the focal length of said plano-convex lens, which is part of the third system is. It follows from this that the image viewed through this third system is an apparent image that is accessible to the eye, due to the possibility of adjustment, that allows accommodation.

As can be seen, the above-mentioned inventive features make it possible to design optical systems of any length, which are practically adjustable to any thickness of a wall of a chamber within practically reasonable limits. One thus obtains a constant spatial expansion in which the distance between the first lens of the second system and the first is diverging at the same time System and the distance between the accommodation lens and the fifth and last lens of the system, as well as the thickness of this five lenses of the second system can be, for example, 10 cm per lens, so that one obtains the ratio that is the focal length of the five lenses of the second system depending on the thickness of the wall to be penetrated gives: 3? ^ (e-1O) / 8. In addition, the above-mentioned features must be taken into account, which affect the position of the lenses of the second system with respect to one another result. For example, assuming a negative optical interval equal to one third of the focal length, then the distance (ensured for example by spacer sleeves) between two lenses of the second system could advantageously can be given by the following relationship:

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d = 2 f - Δ
what gives d = 2 f - f / 3

and finally

leads to d = 5 f / 3.

The invention is explained in more detail with reference to the drawing. The following is shown in detail:

Figure 1 illustrates in a schematic representation the functions that make up the system according to the invention Device consists.

Figure 2 is a view of a section through the optical axis of an embodiment of the invention.

In FIG. 1 one recognizes a device or an optical system which initially has a diverging optical system 1 or a wide angle system in its entire structure. With this one can detect sufficiently illuminated objects that lie within a fixed angle O ( of over 180 °. This creates an apparent image that is located slightly in front of the object. Furthermore, an image transmission device 3 is provided, dei $ at the input end 4 and has an exit end 5, and with which a significantly larger image is given of the entrance image 2, which is located in the area of the exit area 5 of an accommodation system 6 can be seen under essentially the same apparent diameter as the image 2 is seen at the input surface of the transmission device 3. The optical systems 1, 3 and 6 are centered on the optical axis 8 2B.

In the particular embodiment of the optical device according to the invention shown in FIG. 2, the observation is carried out through a thick wall; * this device consists of the same elements 1, 3 and 6, ^w 4? e in figure 1 schematically represented device.

The optical system 1, which is defined above, consists of an optical double line (doublet), which consists of a

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Meniscus 11 with a thick rim and a biconcave lens 12 is composed. The heniskus 11 has a conveying surface with a radius of curvature R 11 which is relatively large in relation to the radius of curvature r 11 of its rear surface. The latter surface is practically hemispherical. The biconcave lens 12 has two mutually symmetrical surfaces with identiscnen radii of curvature R 12. The diameter R 12 is essential, so that the totality of passing through the hemisphere light beams are collected by the biconcave lens larger than the diameter of the ^ri albkugel of the meniscus 11, which benefits the light intensity.

The image transmission system previously described in the second place is composed of five plano-convex lenses L1, L2, L3, L4 and L5, which are identical to one another and have the same mutual spacing. The lenses are separated from one another by spacer sleeves of the same length. The length of a spacer sleeve 31 is chosen such that the front focal point of a lens such as the front focal point F 2 of the lens L 2 on the axis in front of the rear focal point such as the rear focal point Ji "1 of the preceding lens. The distance between two adjacent focal points is called the "optical interval". In Figure 2, only the lenses L 1 and L 2 are shown in their real distance; however, it will be understood that the same spacing exists between lenses L 3, L 4 and L 5. The array of lens L 1 in relation to the Z _we iersatz of the first system is selected such that its front lens focal point F 1 (not shown in the figure) is located slightly in front of the two-substitute; this distance is defined by the spacer sleeve I3. In order to increase the light intensity and reduce the chromatic aberration, it is advisable to choose the arrangement indicated in the figure, namely the alignment of the first flat-biconcave lens with its flat surface in seal on the system, while the other four lenses with their flat Face backwards.

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Jas accommodation system 6 consists of a plano-convex lens L 6 and a visor 61. The lens L 6 has a focal length which is preferably greater than the focal length of the lenses L 1 and L 5, for example, double these focal lengths, which is located behind the lens L 5 at a distance 62 which is approximately equal to the Is half of its focal length. The visor is in one Distance 63 from lens L 6 of approximately three centimeters.

As you can see, the distances between the spacer sleeves 13, 62 and 63 together a few tens of centimeters. These distances can be change slightly, depending on the total length of the invention Contraption. In that i''alle it is about the length 32, the all four sleeves 31 plus the thickness of the lenses combined, and which one has available to measure the length of the device in To reduce dependence on the emergency thickness of the wall to be crossed.

The following examples show how each of these Lengths to be determined:

First example;

The wall thickness is fifty centimeters. Accordingly, the length of the second system is forty centimeters. With a length of JJ spacer sleeve 3 'results in the following:

d = 4-0 / 4- = 10 centimeters. If one takes into account the ratio given here, one obtains:

f = 3 x 10/5 = 6 centimeters.

In this way one chooses for the lenses L 1, L 2, L 3, L 4- and L 5 plano-convex lenses with a radius of curvature of approximately thirty millimeters and possibly also with a display glass 1.53 a focal length of six centimeters. The diameter of the lens is 14 millimeters and the thickness at the strongest point is 5 millimeters.

In the two-lens oval shape 11, 12, R 11 is equal to 25 millimeters, r 11 = 4 millimeters, the diameter D 11 of the meniscus 11 = 18 millimeters, the diameter D 12 of the meniscus 12 = 10 millimeters and the radius R 12 = 7 millimeters; the accommodation lens L 6

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has a diameter of 14 millimeters, a thickness of 5 millimeters and a radius of curvature of the front surface of 63 millimeters. It is located at a distance of 7 to 10 centimeters behind the lens L 5 and by 3 centimeters in front of the visor 61,

Second example;

The thickness of the wall is one meter, here the first and the third system identical to those of the first embodiment be. Accordingly, the length of the second system or transmission system can be 90 centimeters. Man then receives:

d = 90 / 4- = 22.5 cm and f = 3 x 22.5 / 5 = 13.4 cm. There are thus plano-convex for the lenses L 1, L 2, L 3, L4 and L 5 Lenses chosen that have a focal length of 13.4 centimeters to have.

It should be added that the general arrangements of the invention are applicable to the optical treatment of infrared rays emanating from observed objects. It is assumed that that the optics are suitable for the treatment of these rays. A device according to the invention that works with infrared light works, has the advantage that monitoring is possible even in the event of a power failure, which is possible, for example, when monitoring of vaults is very important. Finally, it should be noted that the device according to the invention in cameras for photographic Recordings can be applied, namely by the simple selection of the last lens L 6, which in this one! must be that it can produce an image taken using such devices.

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L e r s e i t e

Claims (4)

28 '113 P a ΐ E li ΐ Α γ ■, j χ κ υ O η Ίο Optical .Jy 3 system arranged on an axis for .öeobachtun ;; of a room through a 'Jand, with the following, along the optical axis successively arranged and interacting elements: a) A first, optical, diverging o.system, aas von der The entirety of the objects at least in front of him there is an initial, apparent image in front of him; b) a second, optical system, the one - ^ ingangsende and one Output end and the length of which is substantially equal to the thickness of the wall and which works converging and is intended to deliver a .nind image of the initial image to the region of its output end; c) a third optical accommodation system that allows a viewer's eye located behind him to see the image can be seen under an apparent diameter substantially equal to that under which the initial image is is sent at the lC input end of said second system, so that the viewing of the entire object across the entire optical system with regard to the image quality is essentially equivalent to the observation that could be made of the initial image directly with the accommodation optical system, but with an extension of the optical system, which is at least equal to the thickness of the wall. 2. Optical system according to claim 1, characterized in that the first optical, diverging system from the following two - ^ elements consists of: a) - ^ inem meniscus with a thick margin, the anterior surface of which has an in With respect to the radius of curvature of its rear surface has a relatively large radius of curvature and its rear, curved surface is approximately hemispherical; b) a biconcave lens attached to the posterior portion of the meniscus is glued (pressed on), and their radii of curvature 909813/0734 - 10 - ORIGINAL INSPECTED much larger than the radius of curvature of the rear are the surface of the meniscus. 3. Optical system according to claim 1 or 2, characterized in that that the third optical system of accommodation consists of a plano-convex lens and a visor, both in one mutual distance are kept between a quarter and half of the focal length of said lens = 4. Optical system according to one of claims 1 to 3 »characterized in that that the second optical system consists of five identical lenses, which are arranged one behind the other and have an equal mutual distance that is slightly smaller than twice their focal length. Optical system according to claims 2 and 4, characterized in that that said second system is arranged at such a distance from the first ay.ütem that the initial image lies in an area which is between the front focal point the first lens of the second system and in the vicinity this lens focal point is located so that the initial image is near the exit end. ü. Optical system according to Claims 2, 3 and 5, characterized in that that said third system can be adjusted in such a way is that it can be brought to a distance from the second system approximately equal to half the focal length of the aforesaid plano-convex lens, so that the observed image is an easily accessible apparent one because of the adjustability Image is. 7 · Optical system according to claim 6, characterized in that each of the five lenses of the second optical system has a plano-convex meniscus with a focal length of about six centimeters is that the mutual distance between two adjacent ones Lentils is ten centimeters and the thickness of the wall to be penetrated is about fifty centimeters. - 11 909813/0734 Optical system olfactory claim b, characterized in that Each of the five lenses of the zv / eiton optic o ^ -stenis is a plano-convex ^ eniskus kit a focal length about equal to 'Lo, 5 Centimeters is the distance between two adjacent ones Lenses is about 24.8 centimeters, and that the jj ic te egg to be penetrated ivand is about one i-; eter. BATH ORIGINAL