FR2756381A3 - Protective filter for fixing to objectives on cameras - Google Patents

Abstract

The filter is fixed to the front edge of the objective on a camera using adhesive rings (1) which are arranged on both sides. A number of such rings are arranged concentrically in layers on a first continuous supporting film (2) beneath a covering sheet (3), in order to accommodate different objective diameters.The filter also has a second supporting film (4) with rings (5,6) which only differ from those on the first film, through being of intermediate sizes. All the rings are continuous, and a piece of black foil can be cut to size and fastened to the objective using a matching adhesive ring

Description

i Protective filters for cameras and cameras,

  so-called UV filters, for example, to protect from UV rays, generally consist of glass,

  sometimes also a plastic screen. They present

  also try for their attachment to the objectives an outer ring provided with a fine thread or a connection to

  bayonet. This implies that the part corresponding to the thread or the bayonet fitting has been provided on the fittings.

  jective. Since the special black filters on the-

  What is the basis of this invention are only intended for one use?

  single reading, manufacturing according to this model would not

  profitable from an economic point of view, in front of the great

  sity of objectives and variants of fittings. In addition, the familiar model of binoculars and spotting scopes is in use.

  principle unsuitable since these generally do not have a threaded connection or a bayonet connection.

  The present invention relates very particularly to black filters with strong attenuation of light and thermal radiation capable of offering the eyes and the devices protection against the extreme conditions of light and thermal radiation during the observation and filming of the partial phase d a solar eclipse (In Central Europe a total solar eclipse is expected in August 1999, a

  event as it happens only one per century). That means

  practically relies on an application that will remain unique since the spectacle of a total solar eclipse can only be observed, most of the time depending on the regions,

  times a century. The filter according to the invention solves the pro-

  problem of individual adaptation to the numerous variety of objectives using the principle of a solution for use

  unique "to throw away" remaining inexpensive while being reliable

  corn. The fixing is indeed carried out not by thread

  or by bayonet fitting but by a self-adhesive ring ad-

  heroic on both sides. The performance of the adhesive material used for this purpose has very often been revealed in use in the form of adhesive discs or tapes for fixing objects to the wall. These self-adhesive rings are presented in different staggered sizes and juxtaposed with each other, the black screen in the form of a cutting film.

  Universality represents one of the advantages of this in-

  vention, that is to say the property of adapting to all the variants of usual objectives, regardless of whether these have a screw or bayonet connection or that they have no possibility of connection, therefore especially in the case of binoculars and spotting scopes. Another advantage is also related to its low cost and the reliability of the filter in the perspective

single use.

  An advantageous embodiment of this invention halves the necessary number of support films allowing the availability of self-adhesive rings. The link

  self-adhesive is no longer carried out around the entire periphery but

part on several sectors.

  Another embodiment has the advantage during manufacture that the cutting of the rings for the three layers which are the cover paper, the self-adhesive ring and the support film can be carried out in a single operation while

  continuing to guarantee the good cohesion of the different bat-

  thanks to several narrow uncut fillets. These last-

  will then be cut inside and out

on the ring in question.

  It is finally possible to also give up these threads and thus the cohesion of the rings, which leads to a

  lot of rings with three layers, of different size and width

  annuities, from which one will choose the desired size.

  Three variants to illustrate this invention are shown in FIGS. 1 to 3: FIG. 1 represents the film

  support (2) cut in the middle and fitted with auto-

  concentric (1) adhesive (covered) covered with their

che (3).

  Fig. 2 shows the support film (4) also cut in

  its middle and provided with self-adhesive rings (5) staggered each

  one half of a ring width and their cover (6) placed in such a way as to allow comparison with the

fig. 1.

  Fig. 3 represents the support film (7) represented by this

  times whole and fitted with dry offset self-adhesive rings

  sector by sector, taking the example of eight sectors.

  Fig. 4 represents the support film (8) and the uncovered rings

  simultaneously weighed presenting the threads (9) spared

  cutting, taking the example of 4 fillets.

  According to a variant not illustrated, the black screen respects

  tif simply consisting of a rectangle cut out of this

  material and having the effect of the required attenuation of the

  light and thermal diation. Its size is provided in function

  tion of the maximum size of the objectives. The fact that spotting scopes have a double optical system, and in this case require two filters, may also be

  taken into account for the calculation of the screen size.

  In this case, the number of additional films should be doubled.

  ports fitted with self-adhesive rings.

  Filters are set up on the objectives in such a way that it is first necessary to take the measures; the staggered execution of the different sizes of self-adhesive rings guarantees, however, that an appropriate size of rings for usual purposes is always available. This operation is favored by the marking of the rings. Once the cover paper has been removed from the selected ring (or from the selected ring section),

  the lens should be pressed against the self-adhesive rings

  hesitating (or the sections of self-adhesive rings) and removing

  the support film with the other rings (the sections of

  selected gues). Only the self-adhesive ring (the sections of self-adhesive rings) on which the black screen will now be pressed remains on the optical system. This will then be cut all around the optical system. First of all, for safety reasons, cleaning the lens edges

  using petrol or alcohol is necessary to remove any traces of fat.

Claims (4)

  1. Protective filter with plastic screen for attachment to telescope and camera lenses   photo and cameras, characterized in that auto-   adhesive on both sides (1) are used for fixing on the front rim of the objectives ;: that a selection of such self-adhesive rings is arranged,   to take into account the various diameters of the ob-   jectives, staggered according to size and width concentrically on a first continuous support film (2) and provided on the upper part with a cover paper (3); a second support film (4) is provided, the rings (5), (6) of which differ from the first support film only in that they are each offset by half their size, that all the rings are characterized by   distinct and clear and end-to-end and that final-   a piece of black film is used to be fixed with the respective self-adhesive ring on the lens and then to be cut out   according to the distinct size of this one.   2. Protective filter according to claim 1 and charac-   terized in that only one support film (7) is provided provided with sections of rings shifted by half a width sector by sector alternately according to the size and this being the reason   for which an even number of sectors has been chosen.   3. Protective filter according to claim 1 and charac-   characterized in that the support film (8) is cut in the form of rings simultaneously with the cover paper and the self-adhesive rings, that, however, when cutting, threads   narrow (9) are spared between all rings for guarantor   pull the cohesion of the rings, and that these fi-   lets are distributed evenly over the entire circumference rings.   4. Protective filter according to claim 3 and charac-   terrified in that we give up the threads and that the rings   three layers composed of cover paper, self-adhesive ring   adhesive and backing film no longer consistent are presented together as an assortment allowing   a selection of rings in the desired size.