|Title of Invention||
"AN OPTICAL DEVICE FOR VIEWING DISTANT OBJECTS"
|Abstract||The invention of Vertical Image Magnifier of Distant Objects is basically a terrestrial telescope with an unusual arrangement of optical components in which the telescope tube is in a vertical position when the object being viewed is straight ahead. The viewing eyepiece near the top end of the tube points towards the object. This makes it possible to turn the telescope around in a very limited space as in a small cabin. The telescope can also be held in hand more steadily in this design with much less discomfort as compared to the existing design. The tripod for this design is much shorter and lighter. Two such telescopes, when joined in a crossed position, can be made into a binoculars.|
|Full Text||DESCRIPTION OF THE INVENTION
The invention of Vertical Reflecting (mirror type) Terrestrial Telescope consists of an arrangement . optical components (namely, mirrors and lenses) that can show a highly magnified and clear image distant objects in the correct orientation and direction.
It is characterised by the use of only mirrors for forming and erecting the image instead of lenses at prisms as used in the conventional terrestrial telescopes. It is also characterised by the feet that the ma telescope tube is perpendicular to the direction of the object being viewed as against the conventioi telescopes, where the tube points towards the object being viewed.
The function and use of the above invention is the same as that of a terrestrial telescope or binocular the new optical principle employed here has many advantages over the conventional instruments.
The shortcomings of the existing conventional terrestrial telescopes and large binoculars and advantages of this invention over the existing ones are described below.
It may be noted here that the conventional terrestrial telescope which is more commonly known a-spotting scope and large binoculars use a pair of right angle prisms to erect the image formed by front lens. One of the prisms inverts the image upside down by two total internal reflections while other reversed the image left to right in the same manner. A telescope may also use a couple of lenses erect the image but this makes it extremely long.
Both, the terrestrial telescope and binoculars are longish in shape and when pointed towards the tarr are horizontal or nearly so depending upon the height of the target. These have some shortcomit which have been overcome in the new optical arrangement of this invention as described below:
1. The conventional instruments, being horizontal, require more space to turn around and cannot
installed in a small telephone booth like cabin. To move the telescope through 360 degn
horizontally, a circular space with diameter equal to the length of the telescope tube and
space occupied by the observer is required, whereas in the new design, a space only slightly
the diameter of the tube (not the length) is required for complete rotation of the telescope (
length of the tube is roughly 6 to 7 times its diameter in most telescopes). Therefore, it can
used in a very small space like a trench and is of particular use to the Army.
2. In the conventional instruments, the tripod must be as high as the level of the eye of a stand
person which is around 5 feet. In the new design, the telescope (or binocular) tube is vertical,
the eyepiece is near the top end of the tube, so the stand has to be only as high so as to reach
bottom of the tube. Thus being shorter, lighter, sturdier and compact.
3. The conventional instruments cannot be used without a tripod stand owing to their weight
excessive shaking of the image by hand vibrations if the magnification power is more than
The vertical tube design allows one to use the telescope/binocular even without a tripod s1
with much less fatigue and discomfort and with reasonably steady image even at 20x po
since the body of the telescope/binocular rests on the viewer's lap and the eyepiece is just at the eye level so one does not have to bend down or stretch up.
4. Unlike conventional terrestrial telescopes and binoculars, this design uses only mirrors for
forming and erecting the image instead of the usual lenses and prisms. The image is therefore,
better colour corrected than in many ordinary instruments.
5. The eyepiece being near the centre of gravity of the tube in the new design, the change in its
height and hence the level of the eye of the viewer is much less than that in normal instruments
while observing objects much above or below the horizon.
6. This telescope can be used as a telephoto lens by attaching a camera at the eyepiece, again a very
compact design compared to normal telephoto lenses.
7. The process of manufacture is simple, cheap and requires little initial investment compared to
that required in the manufacture of the existing ones.
8. The individual mechanical components need not be made with as high precision as is required in
conventional instruments in order to make the instrument work with the required precision. This
will shorten the time required for finishing of the components and assembling of the unit.
In spite of its economy, it does not compromise on the quality as offered by existing instruments. It can have the full range of features like central focusing, individual focusing for the right eye, and adjustable eye distance in case of binoculars.
The utility of instruments of this design is the same as that for the conventional large binoculars, terrestrial telescopes, telephoto lenses and all instruments where a magnified image of a distant object is required.
OPTICAL DESIGN DETAILS OF VERTICAL REFLECTING TERRESTRIAL TELESCOPE.
In the accompanying drawings, fig. 1 is the side view of the vertical reflecting telescope. Fig. 2 is the front view of the same. Fig. 3 is the front view of binocular telescope made by joining two such telescopes. Fig. 4 is the side view of the binocular telescope. Fig. 5 is the side view of the possible variation in design of the telescope.
The working principle of the telescope is described below:
Referring fig.l, light rays from a distant object coming as a parallel beam (1) pass through a plane glass plate (2) and strike a large rectangular or elliptical plane mirror (3) placed in a vertical tube (7) at 45 degrees to the beam. After reflection from this mirror, the beam is deflected downwards at 90 degrees on to a circular concave mirror (4) placed at the bottom of the telescope tube. The concave mirror (4) reflects the light again upwards as a convergent beam which is intercepted by a pair of small 'roof mirrors (or a 90 degree roof prism) (5) placed at 45 degrees to the axis of the beam and is reflected outward of the tube through a hole opposite in direction to the incoming beam (1). 'Roof mirrors are a pair of two rectangular plane mirrors placed edge to edge exactly at 90 degrees to each other. These reflect the light as a plane mirror but reverse the image left to right. A roof prism serves the same purpose. The convergent beam is focused just outside the tube where it forms an image
which is magnified by an eyepiece (6). The image when viewed through the eyepiece is correctly oriented (right side up and non-reversed left to right). The magnification of the system depends, as in any telescope, upon the focal lengths of the concave mirror (4) and the eyepiece (6). The purpose of the plane glass plate (2) is only to close the window in the tube to prevent the optics inside from dust and moisture. Fig. 2 shows the front view of the telescope shown in fig. 1.
The above instrument can either be used singly as a telescope or in conjunction with another such instrument as a binocular as shown in fig. 3.
The binoculars is simply a combination of two telescopes shown in fig. 1 and 2 placed in a crisscross position in a rectangular box (7) as shown in fig. 3. At the cross is a hinge (9) which allows the two telescopes (or one of them if the other is fixed) to rotate about the hinge so that the inter-ocular distance (the distance between the two eyepieces 6 and 6a) can be varied to suit jlhe viewer. Advantage is taken of the fact that the image remains correctly oriented no matter what the orientation of the telescope is (none of them is vertical in this case). Optics of the two telescopes is mounted on metal strips (8) instead of in tubes to make criss-crossing possible, the strips being housed in the rectangular box (7) with a glass window (2) (fig. 4) at the top to allow incoming light. Alignment of the two images is achieved by adjusting one of the two large plane mirrors (3 or 3a). Focusing of the eyepieces can be done either individually or by a common focusing knob.
A possible variation in design (refer fig. 5)
This design is similar to the one shown in fig. 1 except that the convergent beam after reflection from mirror (4) passes through a hole (10) in the plane mirror (3) where it is picked up and deflected by the 'roof mirrors (or prism) (5) towards the eyepiece (6). The advantage here is that the overall tube length is reduced considerably.
The whole instrument (either the single telescope or the binocular telescope) can be mounted on a fork type tripod stand which allows it to move in vertical and horizontal planes to point it in the desired direction.
1 . A terrestrial telescope which is characterised by the use of only mirrors for forming and completely erecting the image (upside down and left to right) in the same direction as the direction of the object which is being viewed. It is also characterised by the feet that the telescope tube is perpendicular to the direction of the object being viewed. It comprises of a vertical cylindrical tube or box with square cross section, near the top end of which is a glass window through which light rays from a distant object enter and are reflected downwards through 90 degrees by a plane mirror which is held at 45 degrees to the direction of the light rays from the object and is placed behind the glass window. The rays travelling downwards are reflected back upwards by a circular concave mirror as a convergent beam which is intercepted by a pair of small roof mirrors held below the plane mirror such that the rays after reflection from these roof mirrors are thrown out of the tube (or box) through a hole in the
said tube or box in a direction opposite the glass window, where they form an image of the object outside the tube or box which is correctly oriented. The large plane mirror, the concave mirror and the pair of roof mirrors are responsible for turning the image upside down while the pair of roof mirrors alone is responsible for reversing the image left to right, thus completely erecting the image. This image is then magnified by an eyepiece for a close up view of the object.
2. A terrestrial telescope as claimed in claim 1 that is used as a telephoto lens in conjunction
with a camera.
3. A terrestrial telescope that is a modification of the telescope claimed in claim 1 and 2 by
introduction of a roof prism or a pair of roof mirrors above the first large flat mirror with a
hole in its centre to allow the convergent beam to pass through it.
4. A terrestrial telescope as claimed in claim 1, 2 and 3 which uses a roof prism instead of roof
5. A binocular with fixed or variable inter-ocular distance made by joining two telescopes as
claimed in claims 1 and. 4.
6. A binocular with central focusing system with individual focus for the right or left eye or
individual focus for both eyes made from two telescopes as claimed in claims 1, 4 and 5.
|Indian Patent Application Number||183/DEL/2003|
|PG Journal Number||41/2007|
|Date of Filing||27-Feb-2003|
|Name of Patentee||VIRESH CHANDRA MATHUR|
|Applicant Address||M-7A, SHALIMAR APTTS., SHALIMAR GARDEN, SAHIBABAD, DIST. GHAZIABAD, U.P.-201005, INDIA.|
|PCT International Classification Number||G02B 23/00|
|PCT International Application Number||N/A|
|PCT International Filing date|