CA2005352C - Graduated filter - Google Patents
Graduated filterInfo
- Publication number
- CA2005352C CA2005352C CA 2005352 CA2005352A CA2005352C CA 2005352 C CA2005352 C CA 2005352C CA 2005352 CA2005352 CA 2005352 CA 2005352 A CA2005352 A CA 2005352A CA 2005352 C CA2005352 C CA 2005352C
- Authority
- CA
- Canada
- Prior art keywords
- filter
- drive
- predetermined
- toothed
- rotation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/007—Optical devices or arrangements for the control of light using movable or deformable optical elements the movable or deformable optical element controlling the colour, i.e. a spectral characteristic, of the light
- G02B26/008—Optical devices or arrangements for the control of light using movable or deformable optical elements the movable or deformable optical element controlling the colour, i.e. a spectral characteristic, of the light in the form of devices for effecting sequential colour changes, e.g. colour wheels
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/20—Filters
- G02B5/205—Neutral density filters
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/006—Filter holders
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Astronomy & Astrophysics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Optical Filters (AREA)
- Blocking Light For Cameras (AREA)
- Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)
Abstract
A preferred embodiment of the graduated filter comprises two bearings for the rotary axles of the two filter discs. The rotary axles are driven by a motor via a belt drive. The belt drive comprises a double belt pulley at the drive shaft of the motor and two toothed belts which wrap around respective toothed-belt pulleys mounted at the rotary axles. Compared with known toothed-wheel gearing, the belt drive is less expensive, more practical, wear-resisting and lighter in weight. The plane of the intersecting axes of rotation of the rotary axles is slightly inclined with respect to the direction of the optical axis of the graduated filter. By virtue of the angular adjustment of the axes of rotation of the rotary axles of the two filter discs, it is rendered possible that the toothed belts snugly fit the running surfaces of the respective toothed-belt pulleys, so that the latter and the toothed belts are uniformly loaded, thus increasing service life thereof and ensuring constant transmission of force.
Description
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BACKGROUND OF THE INVENTION
The present invention broadly relates to optical systems and, more specifically, pertains to a new and improved construction of a graduated filter.
Generally speaking, the new and improved construction of graduated filter is provided with rotatable filter discs which are arranged in the optical axis and jointly driven by an individual or common motor via a gearing, the axes of rotation of the filter discs intersecting the optical axis at both sides.
Graduated filters are part of the continuously variable automatic control of light intensity or brightness in optical systems, especially in photo or motion-picture cameras. Graduated filters comprise plane-parallel transparent or translucent discs which project into the afocal path of a beam and possess a coating variable in the circumferential direction such that light transmission continuously varies upon rotation of the filter discs. In order to avoid reflections in the beam path, the orthogonal or perpendicular line to each filter disc should define with the optical axis an angle of approximately 5°.
BACKGROUND OF THE INVENTION
The present invention broadly relates to optical systems and, more specifically, pertains to a new and improved construction of a graduated filter.
Generally speaking, the new and improved construction of graduated filter is provided with rotatable filter discs which are arranged in the optical axis and jointly driven by an individual or common motor via a gearing, the axes of rotation of the filter discs intersecting the optical axis at both sides.
Graduated filters are part of the continuously variable automatic control of light intensity or brightness in optical systems, especially in photo or motion-picture cameras. Graduated filters comprise plane-parallel transparent or translucent discs which project into the afocal path of a beam and possess a coating variable in the circumferential direction such that light transmission continuously varies upon rotation of the filter discs. In order to avoid reflections in the beam path, the orthogonal or perpendicular line to each filter disc should define with the optical axis an angle of approximately 5°.
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In 3cnown graduated or graded filters of this type, the filter discs are driven by means of a toothed-wheel gearing. This has a number of concurrent disadvantages. One disadvantage is seen in the fact that the gear wheels are subject to wear or abrasion, because they have to be .frequently in motion and such occurs alternately in both directions of rotation. Moreover, the fabrication of such gear wheels is expensive, since a high degree of production accuracy is essential in order to avoid dead zones and vibration or shaking. When the graduated filter is used in aircraft, particularly in space-ships and systems which carry out rapid observation movements, the weight of the gearing is also a factor to be considered. However, the graduated filter is primarily part of an optical system, a normally indispensable lubrication of the gear wheels being a constant source of possible contamination of the sensitive optical parts and components and therefore quite problematic.
Moreover, the graduated filter should be usable at ambient temperatures of up to minus 40°C, so that the variety of suitable materials and lubricants is limited and, accordingly, such limited choice increases the cost for appropriate materials and lubricants.
In 3cnown graduated or graded filters of this type, the filter discs are driven by means of a toothed-wheel gearing. This has a number of concurrent disadvantages. One disadvantage is seen in the fact that the gear wheels are subject to wear or abrasion, because they have to be .frequently in motion and such occurs alternately in both directions of rotation. Moreover, the fabrication of such gear wheels is expensive, since a high degree of production accuracy is essential in order to avoid dead zones and vibration or shaking. When the graduated filter is used in aircraft, particularly in space-ships and systems which carry out rapid observation movements, the weight of the gearing is also a factor to be considered. However, the graduated filter is primarily part of an optical system, a normally indispensable lubrication of the gear wheels being a constant source of possible contamination of the sensitive optical parts and components and therefore quite problematic.
Moreover, the graduated filter should be usable at ambient temperatures of up to minus 40°C, so that the variety of suitable materials and lubricants is limited and, accordingly, such limited choice increases the cost for appropriate materials and lubricants.
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SUMMARY OF THE INVENTION
Therefore, with the foregoing in mind, it is a primary object of the present invention to provide a new and improved construction of a graduated filter of the type described and which does not comprise a toothed gearing and, accordingly does not exhibit the aforementioned drawbacks and shortcomings of prior art constructions.
Another and more specific object of the present invention aims at providing a new and improved construction of a graduated filter which is extremely economical to manufacture and yet affords highly reliable operation thereof without being subject to breakdown and malfunction.
Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the graduated filter of the present development is manifested, among other things, by the features that the gearing comprises a positive or form-locking endless traction-element drive for each filter disc, the traction element of which is highly or intensely deformable at least in the one transverse direction with respect to the direction of travel thereof and is at least partially deformable in the other transverse direction, and that the plane of the axes of rotation of the filter discs does not contain the optical axis.
SUMMARY OF THE INVENTION
Therefore, with the foregoing in mind, it is a primary object of the present invention to provide a new and improved construction of a graduated filter of the type described and which does not comprise a toothed gearing and, accordingly does not exhibit the aforementioned drawbacks and shortcomings of prior art constructions.
Another and more specific object of the present invention aims at providing a new and improved construction of a graduated filter which is extremely economical to manufacture and yet affords highly reliable operation thereof without being subject to breakdown and malfunction.
Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the graduated filter of the present development is manifested, among other things, by the features that the gearing comprises a positive or form-locking endless traction-element drive for each filter disc, the traction element of which is highly or intensely deformable at least in the one transverse direction with respect to the direction of travel thereof and is at least partially deformable in the other transverse direction, and that the plane of the axes of rotation of the filter discs does not contain the optical axis.
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The axes of rotation of the filter discs are advantageously inclined with respect to the axis of the drive shaft of the individual motor in such a manner that the points of the shortest distance between the axes of rotation of the filter discs and the axis of the drive shaft of the individual motor are substantially located in an orthogonal plane with respect to the axis of the drive shaft of the individual motor.
In a particularly preferred exemplary embodiment of the graduated filter constructed according to the invention, the endless traction element constitutes a toothed belt.
In a further exemplary embodiment of the present invention, the endless traction element advantageously constitutes a cord or string provided with equidistantly spaced form-locking bodies.
A practical embodiment of the endless cord or string provided with form-locking bodies can advantageously comprise a ball string provided with equidistantly spaced spherical bodies.
The axes of rotation of the filter discs are advantageously inclined with respect to the axis of the drive shaft of the individual motor in such a manner that the points of the shortest distance between the axes of rotation of the filter discs and the axis of the drive shaft of the individual motor are substantially located in an orthogonal plane with respect to the axis of the drive shaft of the individual motor.
In a particularly preferred exemplary embodiment of the graduated filter constructed according to the invention, the endless traction element constitutes a toothed belt.
In a further exemplary embodiment of the present invention, the endless traction element advantageously constitutes a cord or string provided with equidistantly spaced form-locking bodies.
A practical embodiment of the endless cord or string provided with form-locking bodies can advantageously comprise a ball string provided with equidistantly spaced spherical bodies.
e'~ ~ ~ ~~;:~;.i ~, BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein throughout the various figures of the drawings, there have been generally used the same reference characters to denote the same or analogous components and wherein:
Figure 1 is a top plan view of the graduated filter constructed according to the invention;
Figure 2 is a view of the graduated filter depicted in Figure 1 looking in the direction of the arrows II-II in Figure 1;
Figure 3 is a cross-section through a first filter disc taken substantially along the section line B-B in Figure 2;
Figure 4 is a cross-section through a second filter disc taken substantially along the section line A-A in Figure 2;
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein throughout the various figures of the drawings, there have been generally used the same reference characters to denote the same or analogous components and wherein:
Figure 1 is a top plan view of the graduated filter constructed according to the invention;
Figure 2 is a view of the graduated filter depicted in Figure 1 looking in the direction of the arrows II-II in Figure 1;
Figure 3 is a cross-section through a first filter disc taken substantially along the section line B-B in Figure 2;
Figure 4 is a cross-section through a second filter disc taken substantially along the section line A-A in Figure 2;
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Figure 5 is a view of the graduated filter depicted in Figure 1 looking in the direction of the arrows V-V in Figure l;
Figure 6 is a schematic and partially fragmentary view of a constructional detail illustrating an example of faulty operation;
Figure 7 is a schematic perspective illustration in an oblique view of the graduated filter depicted in Figure 1 looking substantially in the direction of the arrow VII in Figure 1; and Figure 8 is a perspective view of one of the two toothed-belt drives in an inclined illustration, the angles between the axes being excessively depicted for reasons of clarity.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Describing now the drawings, it is to be understood that to simplify the showing thereof, only enough of the graduated filter has been illustrated therein as is needed to enable one skilled in the art to readily understand the underlying principles and concepts of this invention.
Turning attention now specifically to Figures 1 through 5 of i~~~ iaa ~~:, the drawings, a graduated filter 1 illustrated therein by way of example and not limitation essentially comprises a base plate or bracket 2 which supports two filter discs 3 and 4 and a suitable common or individual drive motor or motor means 5 for both filter discs 3 and 4.
The filter discs 3 and 4, which are arranged in the optical axis 6 of the graduated filter l, are mounted at rotary axles 7 and 8, respectively. These rotary axles 7 and 8 are guided in respective bearings or bearing members 9 and which are provided in the base plate or bracket 2. The filter discs 3 and 4 comprise respective glass plates 11 and 12 which are coated on the one side with - in circumferential direction of the filter discs 3 and 4 - continuously decreasing partially transparent or translucent coats or layers 13 and 14, respectively, with the exception of respective sectors 15 and 16 which are not coated.
An optical beam 17, which arrives at the graduated filter 1 from an observed object located in the ambiency of the latter, passes through the filter discs 3 and 4 and reaches, through a bore or borehole 19 located in the base plate or bracket 2, a not particularly illustrated device, for instance a television camera, of the optical system. By rotating the filter discs 3 and 4, the incident light intensity is constantly diminished in a predetermined or _ g _ ~~)(l i: ~ 2 defined manner, so that the optical system is continuously adapted to the varying light conditions of the object and the surroundings thereof.
Toothed-belt pulleys 23 and 24 are mounted at the rotary axles 7 and 8 of the filter discs 3 and 4 by means of screws 21 and 22, respectively, or equivalent structure. The toothed-belt pulleys 23 and 24 possess respective running or bearing surfaces 25 and 26 which are suitably toothed or cogged. The drive shaft 28 of the common or individual drive motor 5 is provided with a double toothed-belt pulley 29 whose running or bearing surfaces are likewise toothed or cogged. The common flank of the double toothed-belt pulley 29 is designated by reference numeral 33. The inventive force transmission member provided between the common drive motor 5 and the respective filter discs 3 and 4 is an endless traction-element drive means. The endless traction-elements depicted in the drawings are toothed belts 35 and 36. The toothed belt 35 wraps around the partial belt pulley 29a of the double toothed-belt pulley 29 of the drive shaft 28 and around the toothed-belt pulley 23 which is mounted at the rotary axle 7 of the filter disc 3. The toothed belt 36 wraps around the partial belt pulley 29b of the double toothed-belt pulley 29 and around the toothed-belt pulley 24 which is mounted at the rotary axle 8 of the filter disc 4.
r ~ r-~, ~~r;w e~~~,~.:a~a ~., In connection with the part of the incident light which is reflected at the filter discs and is to be kept beyond or out of range of the optical system, the bearings or bearing members o.f the rotary axles of the filter discs of a graduated filter are always inclinedly mounted, so that the filter discs are not orthogonal or perpendicular with respect to the direction of incoming light. In other words, the filter discs are likewise inclined relative to the aforesaid direction of incoming light.
In view of the inclined mounting of the bearings or bearing members 9 and 10, the toothed belts 35 and 36 do not snugly fit the running or bearing surfaces 25 and 26 of the .respective toothed-belt pulleys 23 and 24, if no particular corrective measures are taken. In fact, there would be a gap at such locations between the toothed belts 35 and 36 and the toothed-belt pulleys 23 and 24. In Figure 6 there is depicted such a gap 40 between the running or bearing surface 25 of the toothed-belt pulley 23 and the toothed belt 35.
For reasons of clarity this gap 40 has been excessively illustrated. Such faulty traction of the toothed belts 35 and 36 would considerably impair trouble-free operation and cause a one-sided wear of such parts and components and, in particular, of the respective flanks 41 of the toothed-belt pulleys 23 and 24 which are subject to irregular and non-uniformly exerted load. In order to avoid this one-sided ii !--. n. ! c ;; 2~O,a~~,)~ , wear and non-uniform stress resulting from the inclination of the bearings or bearing members 9 and 10 with respect to the direction of incoming light, the axes of rotation 7' and 8' of the rotary axles 7 and 8 of the filter discs 3 and 4 are mutually angularly adjusted in accordance with the invention such that the toothed belts 35 and 36 snugly fit the respective running or bearing surfaces 25 and 26 of the toothed-belt pulleys 23 and 24, respectively.
This angular adjustment of the axes of rotation 7' and 8' of the rotary axles 7 and 8 of the filter discs 3 and 4 will be hereinafter described in conjunction with Figure 7 which is a schematic perspective illustration in an orthogonal coordinate system. For reasons of clarity and better representation all constructional details of the graduated filter 1 have been omitted in Figure 7.
The optical axis 6 of the graduated filter 1 and the axis 27 of the drive shaft 28 extending parallel thereto determine a first plane 51. Orthogonal to the latter and likewise containing the optical axis 6 is a second plane 52.
In view of the aimed-at or required compact type of construction, the toothed belts 35 and 36, schematically depicted in Figure 7 by broken lines conveniently designated by reference numerals 35' and 36' , must extend essentially parallel to the base plate or bracket 2 which, in turn, ~~)t)~~a5~
extends essentially perpendicular to the aforementioned planes 51 and 52.
In known prior art arrangements of filter discs, the axes of rotation of such filter discs, shown in Figure 7 in dash-dotted lines and generally indicated by reference numerals 70 and 80, lie in the second plane 52 and define with the optical axis 6 an angle 38 of, for example, approximately 5°. The points or locations of the shortest distance between the axis 27 of the drive shaft 28 and the prior art axes of rotation 70 and 80 are thereby located at these axes 70 and 80 but slightly forwardly displaced, i.e.
toward the intersection point of the prior art axes of rotation 70 and 80.
Correct guidance of the toothed belts 35' and 36' is ensured only when the toothed-belt pulleys 23 and 24 at their axes of rotation 7' and 8' of the rotary axles 7 and 8 as well as the double-toothed belt pulley 29 at the axis 27 of the drive shaft 28 are placed at respective points or locations of the shortest distance to the respective axes. A
displacement of the toothed-belt pulleys 23, 24 and 29 along axes of rotation 7' and 8' and the axis 27, respectively, is not possible, because they would then reach into the beam path. However, if the shortest distance or connecting line between the axis 27 of the drive shaft 28 and the axes of 2~0~;~~5~:
rotation 7' and 8' of the filter discs 3 and 4, respectively, should essentially extend within the plane which is substantially parallel to the base plate or bracket 2 and extends through the double toothed-belt pulley 29, then the axes of rotation 7' and 8' have to be additionally inclined downwardly in front by an angle 39 of, for example, approximately 0 .15 ° , such angle 39 ,thus being smaller than angle 38 by more than an order of magnitude. The thereby resulting beam offset is negligibly slight.
Figure 8 schematically shows and for reasons of clarity excessively illustrates that, by virtue of the inclination of the angularly adjusted axis of rotation 8' with respect to the axis 27 of the drive shaft 28, the toothed belt 36 again snugly fits the toothed-belt pulley 24 and the partial belt pulley 29b.
While there is shown and described the present preferred embodiment of the invention in which the toothed belts 35 and 36 constitute the endless traction elements, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced. Quite a different type of endless traction element may be used, for example, a ball-type or ball string or a chain and, in fact, any structure of endless traction-element drive which permits the required angular adjustment without being obstructed in its function as a means for force or load transmission.
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Figure 5 is a view of the graduated filter depicted in Figure 1 looking in the direction of the arrows V-V in Figure l;
Figure 6 is a schematic and partially fragmentary view of a constructional detail illustrating an example of faulty operation;
Figure 7 is a schematic perspective illustration in an oblique view of the graduated filter depicted in Figure 1 looking substantially in the direction of the arrow VII in Figure 1; and Figure 8 is a perspective view of one of the two toothed-belt drives in an inclined illustration, the angles between the axes being excessively depicted for reasons of clarity.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Describing now the drawings, it is to be understood that to simplify the showing thereof, only enough of the graduated filter has been illustrated therein as is needed to enable one skilled in the art to readily understand the underlying principles and concepts of this invention.
Turning attention now specifically to Figures 1 through 5 of i~~~ iaa ~~:, the drawings, a graduated filter 1 illustrated therein by way of example and not limitation essentially comprises a base plate or bracket 2 which supports two filter discs 3 and 4 and a suitable common or individual drive motor or motor means 5 for both filter discs 3 and 4.
The filter discs 3 and 4, which are arranged in the optical axis 6 of the graduated filter l, are mounted at rotary axles 7 and 8, respectively. These rotary axles 7 and 8 are guided in respective bearings or bearing members 9 and which are provided in the base plate or bracket 2. The filter discs 3 and 4 comprise respective glass plates 11 and 12 which are coated on the one side with - in circumferential direction of the filter discs 3 and 4 - continuously decreasing partially transparent or translucent coats or layers 13 and 14, respectively, with the exception of respective sectors 15 and 16 which are not coated.
An optical beam 17, which arrives at the graduated filter 1 from an observed object located in the ambiency of the latter, passes through the filter discs 3 and 4 and reaches, through a bore or borehole 19 located in the base plate or bracket 2, a not particularly illustrated device, for instance a television camera, of the optical system. By rotating the filter discs 3 and 4, the incident light intensity is constantly diminished in a predetermined or _ g _ ~~)(l i: ~ 2 defined manner, so that the optical system is continuously adapted to the varying light conditions of the object and the surroundings thereof.
Toothed-belt pulleys 23 and 24 are mounted at the rotary axles 7 and 8 of the filter discs 3 and 4 by means of screws 21 and 22, respectively, or equivalent structure. The toothed-belt pulleys 23 and 24 possess respective running or bearing surfaces 25 and 26 which are suitably toothed or cogged. The drive shaft 28 of the common or individual drive motor 5 is provided with a double toothed-belt pulley 29 whose running or bearing surfaces are likewise toothed or cogged. The common flank of the double toothed-belt pulley 29 is designated by reference numeral 33. The inventive force transmission member provided between the common drive motor 5 and the respective filter discs 3 and 4 is an endless traction-element drive means. The endless traction-elements depicted in the drawings are toothed belts 35 and 36. The toothed belt 35 wraps around the partial belt pulley 29a of the double toothed-belt pulley 29 of the drive shaft 28 and around the toothed-belt pulley 23 which is mounted at the rotary axle 7 of the filter disc 3. The toothed belt 36 wraps around the partial belt pulley 29b of the double toothed-belt pulley 29 and around the toothed-belt pulley 24 which is mounted at the rotary axle 8 of the filter disc 4.
r ~ r-~, ~~r;w e~~~,~.:a~a ~., In connection with the part of the incident light which is reflected at the filter discs and is to be kept beyond or out of range of the optical system, the bearings or bearing members o.f the rotary axles of the filter discs of a graduated filter are always inclinedly mounted, so that the filter discs are not orthogonal or perpendicular with respect to the direction of incoming light. In other words, the filter discs are likewise inclined relative to the aforesaid direction of incoming light.
In view of the inclined mounting of the bearings or bearing members 9 and 10, the toothed belts 35 and 36 do not snugly fit the running or bearing surfaces 25 and 26 of the .respective toothed-belt pulleys 23 and 24, if no particular corrective measures are taken. In fact, there would be a gap at such locations between the toothed belts 35 and 36 and the toothed-belt pulleys 23 and 24. In Figure 6 there is depicted such a gap 40 between the running or bearing surface 25 of the toothed-belt pulley 23 and the toothed belt 35.
For reasons of clarity this gap 40 has been excessively illustrated. Such faulty traction of the toothed belts 35 and 36 would considerably impair trouble-free operation and cause a one-sided wear of such parts and components and, in particular, of the respective flanks 41 of the toothed-belt pulleys 23 and 24 which are subject to irregular and non-uniformly exerted load. In order to avoid this one-sided ii !--. n. ! c ;; 2~O,a~~,)~ , wear and non-uniform stress resulting from the inclination of the bearings or bearing members 9 and 10 with respect to the direction of incoming light, the axes of rotation 7' and 8' of the rotary axles 7 and 8 of the filter discs 3 and 4 are mutually angularly adjusted in accordance with the invention such that the toothed belts 35 and 36 snugly fit the respective running or bearing surfaces 25 and 26 of the toothed-belt pulleys 23 and 24, respectively.
This angular adjustment of the axes of rotation 7' and 8' of the rotary axles 7 and 8 of the filter discs 3 and 4 will be hereinafter described in conjunction with Figure 7 which is a schematic perspective illustration in an orthogonal coordinate system. For reasons of clarity and better representation all constructional details of the graduated filter 1 have been omitted in Figure 7.
The optical axis 6 of the graduated filter 1 and the axis 27 of the drive shaft 28 extending parallel thereto determine a first plane 51. Orthogonal to the latter and likewise containing the optical axis 6 is a second plane 52.
In view of the aimed-at or required compact type of construction, the toothed belts 35 and 36, schematically depicted in Figure 7 by broken lines conveniently designated by reference numerals 35' and 36' , must extend essentially parallel to the base plate or bracket 2 which, in turn, ~~)t)~~a5~
extends essentially perpendicular to the aforementioned planes 51 and 52.
In known prior art arrangements of filter discs, the axes of rotation of such filter discs, shown in Figure 7 in dash-dotted lines and generally indicated by reference numerals 70 and 80, lie in the second plane 52 and define with the optical axis 6 an angle 38 of, for example, approximately 5°. The points or locations of the shortest distance between the axis 27 of the drive shaft 28 and the prior art axes of rotation 70 and 80 are thereby located at these axes 70 and 80 but slightly forwardly displaced, i.e.
toward the intersection point of the prior art axes of rotation 70 and 80.
Correct guidance of the toothed belts 35' and 36' is ensured only when the toothed-belt pulleys 23 and 24 at their axes of rotation 7' and 8' of the rotary axles 7 and 8 as well as the double-toothed belt pulley 29 at the axis 27 of the drive shaft 28 are placed at respective points or locations of the shortest distance to the respective axes. A
displacement of the toothed-belt pulleys 23, 24 and 29 along axes of rotation 7' and 8' and the axis 27, respectively, is not possible, because they would then reach into the beam path. However, if the shortest distance or connecting line between the axis 27 of the drive shaft 28 and the axes of 2~0~;~~5~:
rotation 7' and 8' of the filter discs 3 and 4, respectively, should essentially extend within the plane which is substantially parallel to the base plate or bracket 2 and extends through the double toothed-belt pulley 29, then the axes of rotation 7' and 8' have to be additionally inclined downwardly in front by an angle 39 of, for example, approximately 0 .15 ° , such angle 39 ,thus being smaller than angle 38 by more than an order of magnitude. The thereby resulting beam offset is negligibly slight.
Figure 8 schematically shows and for reasons of clarity excessively illustrates that, by virtue of the inclination of the angularly adjusted axis of rotation 8' with respect to the axis 27 of the drive shaft 28, the toothed belt 36 again snugly fits the toothed-belt pulley 24 and the partial belt pulley 29b.
While there is shown and described the present preferred embodiment of the invention in which the toothed belts 35 and 36 constitute the endless traction elements, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced. Quite a different type of endless traction element may be used, for example, a ball-type or ball string or a chain and, in fact, any structure of endless traction-element drive which permits the required angular adjustment without being obstructed in its function as a means for force or load transmission.
Claims (6)
1. A graduated filter for a beam of light centered on an optical axis, comprising:
rotatable filter discs arranged in the optical axis and interposed in the path of said beam of light;
individual drive means and gearing means;
said rotatable filter discs being driven by said individual drive means via said gearing means;
each rotatable filter disc having a predetermined axis of rotation;
said predetermined axes of rotation of said rotatable filter discs intersecting one another;
said gearing means constituting a form-locking endless traction-element drive provided for each rotatable filter disc and having a predetermined direction of travel;
each form-locking endless traction-element drive comprising a traction element;
said traction element of each said form-locking endless traction-element drive being deformable at least in one transverse direction relative to said predetermined direction of travel; and said predetermined axes of rotation of said rotatable filter discs defining a plane which does not contain the optical axis.
rotatable filter discs arranged in the optical axis and interposed in the path of said beam of light;
individual drive means and gearing means;
said rotatable filter discs being driven by said individual drive means via said gearing means;
each rotatable filter disc having a predetermined axis of rotation;
said predetermined axes of rotation of said rotatable filter discs intersecting one another;
said gearing means constituting a form-locking endless traction-element drive provided for each rotatable filter disc and having a predetermined direction of travel;
each form-locking endless traction-element drive comprising a traction element;
said traction element of each said form-locking endless traction-element drive being deformable at least in one transverse direction relative to said predetermined direction of travel; and said predetermined axes of rotation of said rotatable filter discs defining a plane which does not contain the optical axis.
2. The graduated filter as defined in claim 1, wherein said traction element of each said form-locking endless traction-element drive is further deformable in the other transverse direction relative to said predetermined direction of travel.
3. The graduated filter as defined in either claim 1 or 2, wherein:
said individual drive means comprises a drive shaft having a predetermined drive axis; and said predetermined axes of rotation of said filter discs being inclined relative to said predetermined drive axis such that points of shortest distance between said predetermined axes of rotation and said predetermined drive axis are located in a plane which is sufficiently orthogonal to said predetermined drive axis to make resulting beam offset negligible.
said individual drive means comprises a drive shaft having a predetermined drive axis; and said predetermined axes of rotation of said filter discs being inclined relative to said predetermined drive axis such that points of shortest distance between said predetermined axes of rotation and said predetermined drive axis are located in a plane which is sufficiently orthogonal to said predetermined drive axis to make resulting beam offset negligible.
4. The graduated filter as defined in any one of claims 1-3, wherein:
said traction element of each said form-locking endless traction-element drive constitutes a toothed belt.
said traction element of each said form-locking endless traction-element drive constitutes a toothed belt.
5. The graduated filter as defined in any one of claims 1-3, wherein:
said traction element of each said form-locking endless traction-element drive constitutes a cord provided with equidistantly spaced positive locking bodies.
said traction element of each said form-locking endless traction-element drive constitutes a cord provided with equidistantly spaced positive locking bodies.
6. The graduated filter as defined in claim 5, wherein:
said cord is provided with equidistantly spaced spherical bodies.
said cord is provided with equidistantly spaced spherical bodies.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH474688 | 1988-12-22 | ||
| CH04,746/88-1 | 1988-12-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2005352A1 CA2005352A1 (en) | 1990-06-22 |
| CA2005352C true CA2005352C (en) | 1999-09-07 |
Family
ID=4281801
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2005352 Expired - Fee Related CA2005352C (en) | 1988-12-22 | 1989-12-13 | Graduated filter |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0374565B1 (en) |
| BR (1) | BR8906425A (en) |
| CA (1) | CA2005352C (en) |
| DE (1) | DE58904732D1 (en) |
| EG (1) | EG18768A (en) |
| TR (1) | TR24004A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI258600B (en) * | 2005-02-16 | 2006-07-21 | Prodisc Technology Inc | Light splitter device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2246270A1 (en) * | 1971-09-23 | 1973-03-29 | Ferranti Ltd | DEVICE FOR FORMATION OF AN OPTICAL OPENING WITH VARIABLE AREA |
| GB2074339B (en) * | 1980-04-18 | 1984-01-18 | Ferranti Ltd | Optical attenuator |
| US4443696A (en) * | 1981-08-28 | 1984-04-17 | John Taboada | Optical beam intensity control system |
| US4778263A (en) * | 1987-05-29 | 1988-10-18 | The United States Of America As Respresented By The Department Of Energy | Variable laser attenuator |
-
1989
- 1989-12-04 EP EP19890122325 patent/EP0374565B1/en not_active Expired - Lifetime
- 1989-12-04 DE DE8989122325T patent/DE58904732D1/en not_active Expired - Fee Related
- 1989-12-09 EG EG60389A patent/EG18768A/en active
- 1989-12-13 CA CA 2005352 patent/CA2005352C/en not_active Expired - Fee Related
- 1989-12-13 BR BR8906425A patent/BR8906425A/en not_active IP Right Cessation
- 1989-12-18 TR TR390A patent/TR24004A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| BR8906425A (en) | 1990-08-28 |
| EP0374565A2 (en) | 1990-06-27 |
| CA2005352A1 (en) | 1990-06-22 |
| EG18768A (en) | 1994-01-30 |
| DE58904732D1 (en) | 1993-07-22 |
| EP0374565A3 (en) | 1990-10-31 |
| EP0374565B1 (en) | 1993-06-16 |
| TR24004A (en) | 1991-03-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |